Search

Abstract: A new tar destruction technology has been developed by integrating in-situ catalytic gasification and a hot-gas cleaning system in the catalytic gasification of paper-reject sludge. Experimental results indicated that the tar yield in syngas decreased significantly from 13.64 to 10.76 g/m3, when increasing the zeolite addition during in-situ catalytic gasification. When the syngas passed through the hot-gas cleaning system, the tar concentration measured from downstream was approximately 0.22 g/m3. The hot-gas cleaning system used in this research seems to have played a significant role in reducing tar concentration of the syngas. The major tar speciation identified after hot-gas cleaning system was 1-ring or 2-ring hydrocarbons, which included benzene, toluene, xylene, styrene and naphthalene. In summary, the energy yield efficiency of syngas will be enhanced due to the tar reduction and transformation. The syngas seems to be appropriate to use as a fuel in gas engines for electricity generation. [Copyright &y& Elsevier]

Abstract: An efficient AcO− sensor L which contains 1,10-phenanthroline-based and nitrophenylhydrazine-based groups, and its water-soluble Ru(II) complex were synthesized, characterized and studied in this Letter. Via UV–vis experiments and 1H NMR titration in DMSO solution, it was found that there were potential hydrogen bonds between the NO− after the deprotanation of two –NH during the reaction of L or its Ru complex with anions. Furthermore, an easy-to-prepare test paper was developed to detect AcO− at 10mg/L in pure aqueous solution. [Copyright &y& Elsevier]

• Dynamic responses of auxetic DAHSPs under paper tube-guided air blasts is experimentally conducted. • Large-scale metallic DAHSPs with diverse core configurations are designed and fabricated via folding and vacuum brazing. • Fair comparisons on the blast resistance among different design strategies to vary the core relative density is performed. • Optimal thickness allocation within each layer/among various layers and foam filling for performance promotion are pursued. • Numerical simulations reveal the shock focusing effect and indicate reasonable agreement with the experimental data. Auxetic double arrowhead honeycombs (DAHs) featured by negative Poisson's ratio is attracting increasing attention owing to their tailorable mechanical properties and outstanding energy absorption capability. In this paper, the two-dimensional metallic DAHs were produced and used as the sandwich cores to construct the large-size double arrowhead honeycomb sandwich panels (DAHSPs). A comprehensive experimental investigation on their dynamic responses under the paper tube-guided air blasts was conducted. It majorly focused on the influence of core configurations induced by the variation of core wall thickness, horizontal distance, inclined angles, thickness allocations and foam filling on the deformation/failure modes, associated mechanisms and blast resistance of the target panels. Fair comparisons among different design strategies were performed to evaluate their relative performance. Experimental results show that relative to increasing the core wall thickness, the decrease of horizontal distance is more remarkable to reduce the back face deflection upon the similar weight expense, whereas the effect of inclined angles is limited due to the competition between enhanced bending stiffness and deteriorated transmitted load. A more efficient approach to decrease the back face deformation is to enlarge the inclined angles when the core relative density is relatively low but to decrease the horizontal distance at a high level of relative density. A further improvement of blast resistance can be achieved by allocating more mass to the stuffer wall rather than the tendon one, or by introducing a gradient DAH core instead of the homogeneous one. Compared to adjusting the metallic DAH core itself, the lightweight polyurethane (PU) foam filling is a more competitive manner to promote the blast performance. The preliminary numerical simulations confirmed the shock focusing effect of the paper tube support and indicated reasonable agreement with the experimental results. The present study is supposed to shed light on the design, manufacturing and optimization of auxetic sandwich structures for protection applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper is to describe a simple dynamic crack propagation experiment which reproduces two phenomena: mixed-mode propagation and crack stop and restart. This experiment is explained and interpreted using X-FEM simulations. We show that a simple fracture theory which consists in using a dynamic crack initiation toughness, a crack orientation along the maximum principal stress and a simple equation for the calculation of the crack speed is sufficient to explain what is observed experimentally. [Copyright &y& Elsevier]

Abstract: In many settings, individuals are confronted with decision problems that involve information relevant to their self-image. This paper uses an experiment to explore whether the self-relevance of information influences information processing. The experiment implements two information processing tasks that are identical from a theoretical perspective, but differ in the type of information provided: performance feedback versus information within the context of a purely statistical updating problem. The results suggest that information processing differs significantly across self-relevant and self-irrelevant contexts. In the self-relevant context, except in cases where initial self-confidence is high, subjects overweigh unfavorable performance feedback, leading to overly pessimistic beliefs. This is in contrast to the corresponding self-irrelevant setup, where departures from Bayes’ rule do not follow a consistent pattern in terms of direction, and are smaller in magnitude. In addition, I find that women may interpret positive feedback more conservatively than men, leading to more pessimistic posteriors. [Copyright &y& Elsevier]

A growing literature in philosophy of science focuses on the role of aesthetics in scientific practice, with the experiment recently recognized for its aesthetic value. However, the literature on aesthetics in experimentation grows out of case studies from the history of science, leaving open the question as to how contemporary scientists experience aesthetics in their experimental work. In this paper we offer the first qualitative, empirical analysis of aesthetic experiences regarding experimental practice, drawing from in-depth interviews with 215 scientists in four countries. We identify six categories of aesthetic experience we find in experimentation, their function, and new questions emerging from our study. [ABSTRACT FROM AUTHOR]

This paper systematizes the experimental evidence on gender differences in competition preferences with a meta-analysis of 110 studies and 409 effect sizes on observed or residual gender gaps in experimental tournament entry. Our meta-summary confirms that, across all studies, men choose a tournament scheme 13 percentage points more often than women, which is only about a third of the gap found in Niederle and Vesterlund's (2007) seminal paper. Our meta-regression analysis reveals that larger gender differences are indeed prevalent in studies that most closely apply the Niederle-Vesterlund design, i.e., differences are largest in lab experiments with student subject pools and when math tasks are involved, but almost negligible for other age groups, verbal tasks, and in field-like environments. Experimental interventions such as information treatments or affirmative action measures prove very effective in reducing or even eliminating the gender gap. Although some measures of risk preferences and confidence are systematically related to the estimated residual gender gap in tournament entry, they do not eradicate competitiveness as a distinct trait. Finally, higher gender equality at the country level seems to go along with larger differences in women's and men's competition preferences. [ABSTRACT FROM AUTHOR]

• Twelve rack-to-spine-bracing shear connections were experimentally investigated. • Comprehensive test data were generated using digital image correlation technique. • A component-based analytical model is established for the shear connections. • Three-dimensional behavior of individual components are analytically determined. • Design and construction recommendations for the shear connections are provided. High-rise steel storage racks are cold-formed thin-walled steel frames, which achieve their lateral strength and stiffness by the use of a spine bracing system in the down-aisle direction commonly located at a short horizontal distance away from the main rack frames. The shear connections between the main rack frame and the spine bracing system play a dominant role in the effectiveness of the spine bracing system. This paper experimentally investigates the behavior of the shear connections used in industrial practice between a steel storage rack and the spine bracing system with posts using four groups of three nominally identical connection specimens. By employing a digital image correlation (DIC) system, the tests generate comprehensive data and establish the real-time deformation fields of individual components of such shear connections. Based on the component-based approach, a linear-elastic analytical model is developed for the type of shear connections under consideration. The proposed analytical model explicitly captures the behavior of the individual connection components, including the three-dimensional flexural bending of endplates, as well as the distortions of the open sections of the upright and the bracing post. Based on the proposed model, this paper quantifies the contribution of each component towards the total deformation of the shear connections. The investigation establishes that the cross-sectional distortion of the bracing post and the out-of-plane bending of the upright web are the most flexible components of such shear connections. Recommendations associated with the shear connections under consideration are proposed for the rack designers and manufacturers. [ABSTRACT FROM AUTHOR]

Through searching the literature on the mechanism of acupuncture for primary dysmenorrhea in the last 15 years, this paper summarizes systematically the current study progress on the analgesic mechanism of acupuncture for primary dysmenorrhea, from the perspectives of animal experiment and human trials. In terms of research methods, the behavioral observation, evaluation of central and peripheral biochemical indexes, and molecular biological techniques were mainly used in the animal experiments; whilst the clinical symptoms and evaluation of peripheral serum biochemical indexes were focused on in human trials. As for the research results, the animal experiments showed that acupuncture may play an analgesic role by regulating endocrine, promoting the release of central and peripheral neurotransmitters, regulating immune function, and relieving uterine smooth muscle spasm. However, the human trials have found that acupuncture can produce analgesic effects by regulating serum prostaglandin and ovarian hormone levels, promoting the release of peripheral β-endorphin, improving the uterine artery flow status, and relieving uterine smooth muscle spasm. Although different research methods were used in animal and human studies, the similar results were obtained in acupuncture regulating endocrine levels, promoting release of peripheral neurotransmitters, and alleviating uterine smooth muscle spasms. In addition, at present stage, animal experiments are more than human trials in numbers, and there are relatively few studies on the central mechanism of acupuncture analgesia in human trials. Therefore, in view of this phenomenon, this paper proposes to use functional magnetic resonance imaging (fMRI) technology to explore the central mechanism of acupuncture analgesia in human body, so as to provide a new idea for further exploring the mechanism of acupuncture analgesia in treating primary dysmenorrhea. [ABSTRACT FROM AUTHOR]

This paper delivers a comprehensive analysis of the thermomechanical behavior of steel–concrete (SC) composite elements under elevated temperatures, up to 200 °C, as these can be encountered in accidental scenarios within nuclear power plant operations. The focus lies on the thermal buckling of external thin steel plates. We undertake an integrated approach, combining an experimental campaign and numerical simulations, to investigate thermal buckling phenomena. Using these findings, along with principles from thermoelasticity and thin plate theory, we establish an analytical model to guide preliminary SC element design. The efficacy of this model is ascertained through rigorous comparisons with experimental and numerical results. The paper concludes by demonstrating the model's practical utility for thermal buckling verification through a relevant case study. • Local thermal buckling in SC elements was studied via experiments and simulations. • Database expansion and key buckling factor identification conducted numerically. • Analytical formulas for SC design were derived from thermoelasticity and plate theory. • Formulas were validated against numerical and experimental data for reliability. • Significance of diagonal connector spacing in SC walls was demonstrated. [ABSTRACT FROM AUTHOR]

As basic units of oil tankers and bulk carriers, corrugated bulkheads are usually subjected to lateral loads such as liquid cargo pressure. In this paper, the experiments have been designed and carried out to investigate the collapse modes and ultimate strength of corrugated bulkheads and plane bulkheads under lateral pressure. In the experiment, pure air pressure was used to apply uniformly distributed lateral pressure. The results show that ultimate capacity of corrugated bulkhead is significantly larger than that of traditional T-shaped stiffened plane bulkhead under the same weight of materials. The corrugated bulkhead reaches the ultimate limit state after three plastic hinges formed on the corrugation, and experimental results agree well with the nonlinear finite element analysis. In addition, through numerical analysis, it is found that the boundary conditions considered in this paper have little effect on the ultimate strength of corrugated bulkheads when in-plane displacements are restrained, and the stress and displacement distributions of the mid-span corrugation are similar with five bays of corrugations and above, and can well reflect the corrugated bulkheads in real ships. The results of this paper are helpful to understand the mechanism of corrugated bulkheads collapse and provide references for ultimate strength experimental designs of corrugated bulkhead structures. • Experiments have been designed and carried out for both corrugated and plane bulkhead structures under lateral pressure, by using the test method of pure air pressure loading without any intermediate medium between the tank and the air. This experimental setup can be further extended to such experiments with combined axial and lateral loads. •Numerical analyses are carried out, and both the ultimate strengths and collapse modes match well with the experiments. Collapse behavior has been carefully discussed based on experimental and numerical results. • The design advantages of the corrugated bulkhead are verified by the comparative experimental and numerical analysis of the corrugated bulkhead and the plane T-shaped stiffened plate bulkhead. • The elastic behavior, inelastic behavior and ultimate limit state of corrugated bulkhead under lateral pressure are obtained by comprehensive experimental test and finite element analysis. Also, it has reference value for the evaluation of the ultimate capacity of the corrugated bulkhead model in the actual ship. • The collapse mode of corrugated bulkheads has similarity with that of fixed/simply supported beams at both ends. It is found that when three plastic hinges are generated in middle and ends of the center corrugation, the corrugated bulkhead has reached ultimate limit state. • The results by NFEM show that the discrepancy on the ultimate pressure of corrugated bulkhead under clamped and simply supported boundary conditions is small only when the in-plane displacement is fully restrained at the boundaries, and the clamped supported boundary conditions have better robustness and matches well with the experimental results. • It is found that when the number of corrugations is small (e.g., three in this study), the distribution of stress and displacements of the central corrugations changes obviously compared with original case, indicating that it is greatly affected by boundary constraints. [ABSTRACT FROM AUTHOR]

Rephrase is a pragmatically complex and persuasively appealing, yet still not systematically explored communication phenomenon. Evidence from corpus data indicates that speakers rephrase frequently in argumentative settings. In light of this empirical evidence, it is a tenable assumption that speakers (are perceived to) gain rhetorical advantages by rephrasing their own or someone else's contribution. In this paper, we present three experimental studies that seek to shed light on the potential persuasive appeal of rephrase. In our set of experiments, we exploit examples taken from the corpora of rephrased arguments annotated with OVA+ (Online Visualisation of Argument) software as material for the design of experiments that seek to test the rhetorical effectiveness of two sub-types of rephrase, namely rephrase specification and rephrase generalization. In particular, we observe whether judgements on persuasiveness are related to judgements on the perceived trustworthiness of the speaker. Our results suggest that rephrasing a contribution can impact both the perceived persuasiveness of a message and the perceived trustworthiness of the speaker. Moreover, our findings indicate that speakers perceive the segments connected through a rephrase relation as being very similar in content, which in turn suggests that rephrase is not perceived as providing a separate argument. • Experimentally investigates rhetorical effectiveness of rephrase strategies in argumentation. • Considers both perceived persuasiveness and ethotic effects. • Provides evidence that rephrase behaves like an argument but is not perceived as one. • Explains how experimental methods can inform corpus methods in the study of argumentation. [ABSTRACT FROM AUTHOR]

• Combination of the absorption and vapor compression heat pump. • Maximum performance enhancements for heating is 45.8%. • Maximum performance enhancements for cooling is 18.9%. • Power savings for heating and cooling are 16.0% and 31.4%, respectively. • Lower the heat-driven temperature for absorption to 60 °C. Decarbonizing the energy sector becomes a key topic to solving man-made climate change. For achieving indoor thermal comfort conditions, conventional heating, ventilating, and air-conditioning systems consume so much energy in both residential and public buildings. In this paper, a novel solar-assisted absorption-compression system for both heating and cooling is proposed to utilize solar thermal energy throughout the year for the heating/cooling supply. The experimental prototype was built and operational modes including solar-assisted heating/cooling mode and vapor compression individual heating/cooling mode. The performance enhanced by assisted heat input of the proposed system is evaluated by comparing it with air-source heat pumps operated under the same ambient conditions. Performance indices consisting of COP ele increment, power-saving ratio (PSR) and energy-saving ratio (ESR) are presented. The results indicate that the combination of the absorption heat pump subsystem and the vapor compression subsystem lowers the heat-driven temperature to 60 °C and thus makes higher solar collection efficiency possible. The maximum of the COP ele increment and the PSR under solar-assisted heating mode are achieved at conditions with 80 °C hot water temperature, of 45.8% and 31.4%, respectively, and the corresponding value for solar-assisted cooling mode are 18.9% and 16.0%. The speed of compressor as well as fan frequency of terminal has a greater influence on heating performance that on cooling performance due to the different coupling mechanisms. [ABSTRACT FROM AUTHOR]

The paper aims to examine the possibility of improving the manufacturing process for MCFC cathodes. using noble, semi-precious, and rare earth metals sourced from waste electric and electronic equipment (WEEE). As MCFC components are not particularly sensitive to ceramic and metal impurities. The addition of noble metals recovered from WEEE as catalysts are economically justifiable. The reported experimental research revealed the positive impact of MCFC cathode fabricated with 20% recycled electronic scrap. Especially the cell with powder marked as 4/1 enjoyed much better performance operating at 550 °C than the reference cell. During the operation at a temperature of 650 °C, the cell with powder marked as 4/1 has almost the same performance as the reference cell, i.e., 1.01 V OCV and power density of 0.13 A/cm2. The cell with cathode with 4/2 powder has the worst performance – current density of 0.09 A/cm2 and OCV of 0.97 V. [Display omitted] • Rare earth elements separated by positive charge contains less cerium than separated by negative charge. • The maximum current densities and Open Circuit Values are similar as reference case for maximum gas flows. • The maximum current densities and Oper Circuit Voltages are better with additives for lower operational temperature. [ABSTRACT FROM AUTHOR]

Many daylight metrics are developed to assess different aspects of visual comfort in recent years. However, there are still some doubts about the robustness of these metrics. This paper presents a comprehensive and thorough analysis of 58 field studies and lab experiments (2012–2020), focusing on metrics used to predict occupants' acceptance and visual preference in indoor environments. The review first covers the methodology of studies. Second, the results are discussed in four main categories: 1) confounding parameters in visual comfort studies; 2) metrics' accuracy; 3) newly defined metrics or modified versions of the existing ones, and 4) metric thresholds. Finally, the lessons learned and limitations of the existing studies and recommendations for future studies on visual comfort are presented. Going through the results of those studies focusing on finding a proper metric for visual comfort evaluations revealed some of the previous studies had limitations in the experimental, statistical, and equipment. Ignoring these issues may have biased the studies' findings. According to results, there is still a lack of consensus on adequate illuminance thresholds. Moreover, due to the complexity of the visual comfort concept and occupants' perception dependency on diverse factors, there is no global glare metric that could be applied to various conditions. To address these gaps, this study presents future researches trends, including the development of comprehensive study protocols, long-term glare assessment, and refining metrics thresholds. The findings of this paper could help researchers facilitate the application of filed and lab studies in visual comfort studies. [ABSTRACT FROM AUTHOR]

The prediction of the fire hazard of a tank during burning of leaking contents is significant during the emergency response to tank fire accidents. A detailed investigation was conducted in small-scale tank fire experiments with different filling levels and tray sizes. The liquid (n-heptane) leaked from the tank and burned in the containment structure (the tray) below, heating the tank and emitting radiative heat flux to the surroundings. The temperature of the leaking contents increased as the heating progressed and eventually reached its boiling point. When the leaking contents boiled and burned, the fire hazard was the greatest because the internal pressure increased rapidly, and the mass burning rate and thermal radiation reached a maximum. Modifying the previous models, this paper proposed a virtual tray modeling approach for predicting the mass burning rate and thermal radiation during the burning of boiling leaking contents. The maximum relative error between measurement and prediction was approximately 20%, indicating the availability of the modified models. A three-dimensional transient simulation was set up using the computational fluid dynamics (CFD) technique to predict the temperature response of the leaking contents, and thus, the elapsed time before boiling and burning of the contents was well predicted. These results can provide scientific support for emergency response teams to control similar tank fire accidents. [ABSTRACT FROM AUTHOR]

Lifeboats have been serving as an essential maritime life-saving equipment in the case of emergency situations. In recent decades, much effort has been devoted to investigating water entry/exit behaviors of lifeboats as well as occupant safety. However, there exist very few review papers related to such an important topic. In light of this, the purpose of the current work is to present a comprehensive literature review to fill the gap. This is achieved by firstly summarizing the existing studies concerned with water entry/exit of lifeboats from the perspective of numerical simulations and experimental investigations. To be specific, numerical approaches for fluids, structures, and fluid-lifeboat interactions, are categorized, followed by two major experimental methods for water entry/exit of lifeboats. We then present common evaluation criteria, numerical approaches, and experimental methods for occupant safety during water entry/exit process. Finally, the performance of numerical approaches and experimental methods for water entry/exit of lifeboats and occupant safety is discussed, and some future directions are pointed out. The present review can serve as a useful guidance for researchers who are interested in this topic. • A comprehensive review for water entry/exit of lifeboats and occupant safety • Numerical and experimental approaches for water entry/exit of lifeboats • Evaluation criteria, numerical approaches, and experimental methods for occupant safety • Thorough discussion of performance of numerical approaches and experimental methods • Future research directions for numerical and experimental methods [ABSTRACT FROM AUTHOR]

The fire resistance of building assemblies can be determined through testing or by numerical modelling. As testing of building assemblies is expensive and time-consuming, the development of numerical modelling methods is gaining momentum. One of the challenges in modelling assemblies' thermal performance is insulation dimensional shrinkage at elevated temperatures. To address this challenge, this paper presents a comprehensive experimental investigation into the shrinkage of glass and mineral fibre insulation materials under elevated temperature conditions. Initially, a series of tests was conducted to establish the temperature range within which significant shrinkage occurs for both types of insulation. Then, visual observations and measurements were recorded to assess the physical and dimensional changes of the insulation materials within the identified temperature range for shrinkage, indicating distinct responses of glass and mineral fibre insulation to thermal exposure. Compared to width and length variations, thickness reduction in insulation was more significant. Overall, the insulation thickness decreased as the exposed temperature increased. The glass fibre insulation completely melted at 710 °C, while mineral fibre insulation disintegrated at 1000 °C. In addition, empirical equations were derived to assess the thickness variations of these insulations at elevated temperatures, which can greatly enhance the accuracy of future thermal models under fire scenarios. Lastly, potential areas for future research are identified. • Glass fibre shrinks notably between 600 °C and 710 °C; mineral fibre, 700 °C to 1000 °C. • Glass fibre melts at 710 °C; mineral forms shell at 850 °C, disintegrates at 1000 °C. • Proposed equations to predict insulation thickness changes at high temperatures. • Comparative analysis with full-scale tests confirms the study's findings. [ABSTRACT FROM AUTHOR]

• A new track vehicle model over rigid horizontal and inclined surfaces. • A model that accounts for the distribution of the normal forces along the track. • Pure turning over inclines can cause substantial sliding. • Analytical modeling is validated with experimental results. This paper studies the locomotion of a robot fitted with flexible rubber tracks while driving and climbing over rigid horizontal and inclined surfaces. We developed a model that accounts for sliding during rotation and the distribution of the normal forces along the track. On horizontal surfaces, we found that the size of the robot (width and length) and the normal force distribution along the track had a substantial influence on its turning speed and radius, whereas the coefficient of friction (COF), the robot's mass and inertia had a much lesser influence. The model shows that on inclined surfaces, even on relatively small slopes, the robot substantially slides downwards as it tries to rotate. The results of the model and the simulations were validated using a tracked vehicle that was built and tested on a solar panel. The experimental results of the turning radius and rotational speed were within 2% of the model (see video). [ABSTRACT FROM AUTHOR]

• We provide an experimental test of the causal role of asymmetric information for sustaining relational contracts. • We study the role of asymmetric information in both trust contract and bonus contract settings. • We find that asymmetric information has strong consequences for the distribution of rents. • However, it does not reduce efficiency of relational contracts. • Our paper therefore contributes to the understanding of the formation of relational contracts and how they are affected by variations in information. Work and trade relationships are often governed by relational contracts, in which incentives for cooperative action today stem from the prospective future benefits of the relationship. In this paper, we study how a lack of hard information about the costs of providing quality, and therefore about the financial consequences of actions, affects relational contracts in buyer-seller relationships. The absence of verifiable information can impede the joint understanding of what constitutes cooperative behavior, and may thus inject mistrust into relationships. Comparing seller-buyer relationships with hard (verifiable) and soft (non-verifiable) information about seller costs in the laboratory, we find that soft information affects the terms of relational contracts. However, the party negatively affected by these adjustments does not reciprocate with efficiency-reducing actions. We therefore find that asymmetric information only affects the distribution of rents, and not efficiency. [ABSTRACT FROM AUTHOR]

• Damaged RC slabs strengthened with UHPC layer were tested in laboratory and applied in field. • Two different load patterns: negative bending moment and positive bending moment. • Two different curing conditions: normal temperature curing and high temperature steam curing. • Calculated flexure capacity by analytical models developed theoretically agreed well with experimental values. Based on strengthening a damaged bridge deck in the field, this paper conducted flexural experiments on a scaled damaged bridge deck strengthened by reinforced ultrahigh performance concrete (UHPC) layer with high temperature steam and normal temperature curing; this paper investigates cracking capacity, ultimate capacity, deformation features and failure mode of RC-UHPC composites under positive bending moment and negative bending moment, respectively. Experimental results indicate that cracking and ultimate capacity of composites increased by about 2.5 and 2 times respectively with UHPC located at tension face comparing with intact RC slab; while for UHPC at compression face, no change in cracking capacity was observed and ultimate capacity was 30% higher than that of intact RC slab. Meanwhile, stiffness also obviously increased with tensile stress in steel reinforcement in RC slabs, decreasing after strengthening for all strengthened slabs; and propagation of cracks in RC slabs was restrained and delayed due to ultrahigh ductility and behavior of strain hardening of UHPC. Based on experimental results and failure mode, analytical equations for cracking and ultimate flexure capacity of UHPC-RC slabs were constructed, and applicability of equations was validated by some experimental results in this paper and other literature with good accuracy by predicted equations. Finally, the research achievements of this paper were effectively applied on the reinforcement design of damaged deck of main girder in a cable-stayed bridge. [ABSTRACT FROM AUTHOR]

Abstract Determining time-dependent mechanical properties of soft materials is essential in understanding their deformation behaviors under various stimuli. This paper investigates the use of indentation creep tests to measure the viscoelastic properties of soft materials at local areas. A simple scaling law between the reduced creep function and the creep displacement of the indenter is revealed in this paper based on a theoretical analysis. We show that the scaling relation can be used to interpret indentation creep tests of viscoelastic soft solids with arbitrary surface profile provided that the contact area does not change. Both numerical and practical experiments have been performed to validate the theory and the analytical solution. In our experiments, a low-cost portable indentation system is proposed to measure the reduced creep function. Our results show that the low-cost instrument and the analytical solution to interpret the experimental data reported here represent a useful testing method to deduce the intrinsic viscoelastic properties of soft materials in a non-destructive manner. Highlights • A simple scaling law between the reduced creep function and the creep displacement of the indenter is derived and validated with finite element analysis. • A low-cost portable indentation system is presented to measure the reduced creep function. • Experiments on phantom gels demonstrate the usefulness of the method and instrument. [ABSTRACT FROM AUTHOR]

Abstract The local cross-section behaviour of stainless steel channel sections under the combined actions of axial compression and minor axis bending moment is investigated in the present paper and its companion paper, based on a comprehensive experimental and numerical study. Two channel section sizes were considered in the experimental programme, with the test specimens laser-welded at the two flange-to-web junctions from hot-rolled EN 1.4307 and EN 1.4404 austenitic stainless steel plates. The experiments involved initial local geometric imperfection measurements and 15 eccentrically loaded stub column (combined loading) tests. The loading eccentricity was varied to achieve a range of ratios of axial compression to minor axis bending moment; both orientations of bending (web in compression and web in tension) were considered. The test setup and procedures, together with the key experimental observations, including the load-carrying and deformation capacities, load-end rotation histories and failure modes, are fully reported. A finite element simulation study is then presented, in which the models were first validated against the obtained test results and then employed, in the companion paper, for parametric investigations and the assessment of design provisions. Highlights • Laser-welded stainless steel channel sections under combined compression and minor axis bending moment has been studied. • An experimental programme including 15 combined loading tests has been carried out. • Finite element models have been developed and validated against experimental results. [ABSTRACT FROM AUTHOR]

Abstract The paper numerically investigates the structural response of log-house (or log-haus, Blockhaus , etc.) timber buildings under seismic loads. The typical log-house system consists of a series of timber members, stacked horizontally one upon another. There, the mechanical interaction is given by traditional timber joints with carvings, multiple contact surfaces, friction phenomena. Even though log-house systems are widely used for the construction of wooden houses or commercial buildings in earthquake-prone regions, no design provisions are currently given in design standards. In this paper, a Finite Element (FE) numerical investigation is performed in ABAQUS on full three-dimensional (3D) log-house buildings subjected to seismic loads, as an extension of past studies focused on single components and walls only. In the typical FE model, the cyclic behaviour of carpentry joints at the interception between multiple logs and walls is properly accounted, including frictional effects and possible tolerance gaps due to the construction process. Nonlinear dynamic analyses are carried out on a set of selected building configurations of technical interest for design, giving evidence of their structural performance. Based on the so collected parametric FE results, estimations of the q-behaviour factor are hence discussed. As shown, the FE data suggests that - compared to other timber structures - a larger inter-storey drift should be considered for the seismic design of log-house buildings. In addition, the same FE results show that a q-behaviour factor up to 2.8 can be accounted. Highlights • The structural response of log-house timber buildings under seismic loads is numerically investigated. • Full 3D buildings are described in their key features, via simplified but accurate FE models. • Validation of the FE modelling approach is carried out towards past shake table experiments. • FE parametric seismic analyses are carried out on selected 3D buildings constructed in Italy. • Key aspects and influencing parameters are emphasized, including q-factor estimations for log-house buildings. [ABSTRACT FROM AUTHOR]

Highlights • Captured multi-view images by integral imaging are low-resolution images since image sensors are divided and used by lenslet arrays. • Conventional 3D reconstruction techniques cannot provide high-resolution 3D images from low-resolution multi-view images. • Pixel-to-pixel mapping technique can provide accurate pixel positions on reconstruction planes. • Our proposed method (CPERTS) reconstructs visual quality enhanced 3D images by considering the diffraction pattern of the virtual pinhole using convolution operator. Abstract In this paper, we propose a new visual quality enhancement of a three-dimensional (3D) computational reconstruction algorithm in integral imaging. Integral imaging can record 3D images easily using a lenslet array. However, the elemental images may have low resolution, because each image cannot use full resolution of an image sensor. To solve this problem, a computational reconstruction technique can be used to reconstruct visual-quality-enhanced 3D images from low-resolution elemental images. Our method is based on the pixel of elemental images rearrangement technique (PERT), which can provide enhanced visual quality of the reconstructed 3D image compared with that of conventional computational reconstruction algorithms. However, it has a problem in which the size of 3D scenes is different from the optical reconstruction results. Therefore, in this paper, we propose a solution considering empty spaces between back-projected pixels on the reconstruction planes and enhance the extensibility using the convolution operator. Our experimental results show the enhancement of the visual quality and resolution of the reconstructed 3D images using the point-spread function filter. [ABSTRACT FROM AUTHOR]

• Twelve connections between high-rise racks and the spine bracing were experimentally investigated. • Comprehensive test data were generated using digital image correlation technique. • A component-based model is established for the rack-to-spine-bracing connections. • Component deformation patterns are explicitly considered in the analytical model. • Design recommendations are provided by performing analytical studies. The primary lateral load resisting system of the high-rise braced steel storage racks is the spine bracing located at a short distance away from the rear rack frames. The connections between the rack frames and spine bracing, which transmit the horizontal stabilizing forces, dictate the effectiveness of the spine bracing and the global performance of the entire high-rise racking system. The first part of this paper experimentally establishes the behavior of the connections between the racks and the spine bracing under lateral loads, utilizing four groups of three nominally identical test specimens. A digital image correlation (DIC) measurement system is employed to generate comprehensive data associated with the behavior of individual components of such connections. The behavior of the connection components is quantified and discussed based on the three-dimensional deformation field recorded by the DIC system. The second part of this paper develops a component-based elastic analytical model for the connections between the racks and the spine bracing under consideration. The endplate spatial flexural bending mechanism, as well as the upright cross-section distortional behavior, are explicitly considered by the analytical model. The contributions of each individual component towards the total deformation of the connections are quantified. The paper concludes with design and construction recommendations for the enhancement of the connections between the racks and the spine bracing, while recognizing the limitations of this research. [ABSTRACT FROM AUTHOR]

Composite materials have been widely used in the field of pressure shells for underwater vehicles due to their great potential. This paper presents an experimental study of composite cylindrical shells with and without the circular hole subjected to external hydrostatic pressure. The mechanical response of the composite cylindrical shells under external hydrostatic pressure is recorded by the strain acquisition system, and the buckling deformation process of the shells is also captured by the high-speed camera system. According to the experimental results, the entire compression process of the shell can be divided into three stages based on variations in strain. Based on the findings that buckling starts very early and accounts for about 35 % of the entire process, the concept of initial buckling pressure is proposed to distinguish the critical point of the shell transition from a stable state to an unstable state. It is found that the damage positions of the three shells all correspond to the troughs in the buckling waveform, and the final fiber breakage of the perforated shells with the reinforcements both occur near the reinforcement component. Finally, a comparative analysis of the strain response of the shell with the hole and the complete shell is carried out to explore their similarities and differences. The experimental results in this paper provide valuable information for the design of perforated composite pressure shells for underwater vehicles. [ABSTRACT FROM AUTHOR]

Highlights • Conducted an experimental investigation on short SHS columns strengthened with different CFRP wrapping systems. • Developed and validated FE models to simulate CFRP strengthened short SHS columns. • Conducted a parametric study on the effect of steel section, CFRP orientation and steel grade on the capacity. • Developed new design equations for the compression capacity of CFRP strengthened short SHS columns. Abstract This paper presents the details of experimental and numerical investigations on the behaviour and axial compression capacity of Carbon Fibre Reinforced Polymer (CFRP) strengthened cold-formed, short Square Hollow Section (SHS) steel columns. Initially, an experimental investigation consisting of seven test columns was conducted to investigate the influence of CFRP strengthening layout on the axial compression capacity of short SHS steel columns. In addition, the effect of CFRP wrapping end condition was also investigated. Experimental results showed that CFRPs are very effective in strengthening short SHS columns, where axial compression capacity enhancements up to 2.6 times were observed. Then a numerical simulation was implemented using ABAQUS by which CFRP and adhesive were modelled using continuum and cohesive elements deploying Hashin and cohesive law criteria. The finite element models were validated using experimental results and then used in a detailed parametric study. Using the finite element analysis results suitable improvements were proposed to the existing design equations available in the literature. Finally, a new set of design equations based on Direct Strength Method (DSM) is proposed in this paper to determine the axial compression capacity of CFRP strengthened SHS columns subjected to local buckling. [ABSTRACT FROM AUTHOR]

The majority of shear tests reported in the literature has been performed on simply supported reinforced concrete beams under point loads. In contrast, this paper focuses on the shear behaviour of post-tensioned T-beams with no or a minimum amount of transverse reinforcement under various loading conditions. Several test setups were used to investigate the influence of different distributions of the internal forces (due to uniformly distributed load and point loads, respectively) and of the shear slenderness on the shear resistance of the beams. Furthermore, the difference in the shear responses at the end support and the intermediate support of the beams was analysed using the experimental results. The experimental programme consisted of eight shear tests carried out on four specimens. With the aid of close-range photogrammetry, detailed measurements of the kinematics of the critical flexural shear cracks were taken. Linking well-known constitutive laws for concrete and steel with the relationship between the opening and sliding of critical cracks (determined using digital image correlation of experimental results) allowed the contributions of several shear transfer actions to the shear resistance to be estimated. In this paper, it is demonstrated that this approach leads to a better mechanical understanding of the actual shear behaviour of post-tensioned beams. The analysis illustrates that arching action plays a major role regarding the shear resistance of slender post-tensioned beams. [ABSTRACT FROM AUTHOR]

The Romanian territory has an important seismic potential in Europe, with the Vrancea source. The most destructive seismic events that occurred in Romania in the 20th century (November 10, 1940 and March 4, 1977) have revealed a high level of seismic vulnerability of the built environment. An important part of this built environment is represented by historical buildings, including the traditional ones (timber frame and infills from various materials as brick, stone, adobe, etc.). The investigations after seismic events from November 10, 1940 and March 4, 1977, revealed that the traditional buildings did not suffer any or important damages, thus showed their particular seismic behavior. Both the experience after similar seismic events from other countries as Turkey, Haiti, China, Myanmar, etc. and research studies from countries like Portugal, France and Japan, revealed an unexpected good behavior of such of buildings. Therefore, in this paper the results of the static cyclic tests on walls are presented. The test specimens were built according to the findings of the field investigations done on traditional buildings from Romania which are briefly presented hereby. The typology on which this paper focuses is the one found as predominant in the investigated areas (around the Vrancea seismic source). [ABSTRACT FROM AUTHOR]

To apply the Direct Strength Method (DSM) to web crippling of lipped channel sections, experiments were recently conducted under EOF and IOF loading conditions. In the research presented here, finite element models were first developed to predict the elastic buckling loads and the elasto-plastic behaviour, both of the experiments and an extended data set. New first- and second-order elasto-plastic theoretical models describing the plastic mechanism initiation of a 2D cross-sectional strip of the lipped channel sections were then developed. Subsequently these 2D cross-sectional models were transformed to full 3D models by using modelled yield line patterns as observed in the finite element simulations. Both the first- and second-order 3D models correlate well with the full section simulations. DSM equations were calibrated based on the results from the simulations, using several alternatives for the yield load as needed in the DSM: a first yield load from the finite element simulations; a rigid-plastic mechanism initiation load as used by other researchers; and a first-order elasto-plastic mechanism initiation load via the above theoretical models. Finally, these calibrated DSM equations were compared with the theoretical models, design codes, and a basic Merchant-Rankine approach. For the DSM, the first order rigid-plastic yield load, most appropriate for the DSM and used by other researchers also, performs best for IOF load cases. For EOF load cases, however, using the first-order elasto-plastic load in the DSM gives best results. Taking these different yield loads for the different cases then, the DSM outperforms Eurocode, AISI S100, and the basic Merchant Rankine predictions. The DSM is intuitively and relatively easy to use, and this paper shows that widening its scope to web crippling of lipped channel sections is possible. Importantly, this paper steps into the discussion for a certain type of yield load to be used in the DSM for web crippling, and gives several arguments to consider the rigid-plastic mechanism initiation load. [ABSTRACT FROM AUTHOR]

The importance of private sector engagement on risk reduction is increasingly mentioned over the last years. The Sendai Framework for Disaster Risk Reduction 2015-2030 stresses that the private sector should be a crucial partner in achieving disaster resilience. However, the contribution by the private sector is still rare and mostly undertaken by large multinational firms with just a few positive impacts on the local level. Particularly manufacturing firms are heavily exposed to floods in Indonesia; Jakarta and Semarang are prominent examples. Broader flood risk reduction measures are still insufficiently developed. Therefore, it is argued that firms can reduce the flood risk through collective adaptation measures. We understand collective adaptation as collaborative activities to reduce risks that firms are either initiating or participating together with other firms, the community, NGOs and authorities. Our own research has revealed that particularly small and medium-sized enterprises (SMEs) rarely engage in collective flood adaptation. Based on our findings, this paper examines which circumstances determine the willingness of SMEs to contribute to flood risk reduction. Instruments in order to increase the willingness to collective adaptation are also discussed. Scenario-based experiments with 120 SMEs have been conducted in Jakarta and Semarang. These scenarios contain different risk reduction measures (polder system, river expansion and sensitization program), each with different actors’ constellation of contribution. Comparative logistic regressions have been applied to determine context-specific factors, e.g. risk behavior, firm-specific characteristics or level of flood-proneness that influence the willingness to contribute to flood risk reduction. Overall, the paper provides deeper insights in understanding firms’ engagement in flood risk reduction and gives answers of how firms can be motivated to become an active player on building resilience. [ABSTRACT FROM AUTHOR]

• Commercial PV modules are experimentally and numerically investigated in mechanical terms. • A non-destructive diagnostic strategy based on vibration frequency analysis is proposed. • The attention is given to encapsulants consisting of thin interlayers made of Ethylene-Vinyl Acetate (EVA) • The effect of ageing, ambient conditions, humidity on EVA films is emphasized. • Results show that the frequency analysis can capture the encapsulant deterioration and prevent major faults. In engineering applications, the frequency analysis represents a first and practical step to collect relevant parameters for structural and mechanical diagnostics. Any possible material / component degradation and deterioration can be prematurely detected by frequency modifications that exceed a certain alert value. In this paper, the attention is given to the dynamic mechanical analysis of commercial photovoltaic (PV) modules, in which the solar cells are typically encapsulated in thin viscoelastic interlayers made of Ethylene-Vinyl Acetate (EVA), which are primarily responsible for the load-bearing capacity of the sandwich PV system. As a major effect of ageing, ambient conditions, non-uniform / cyclic thermal gradients, humidity and even extreme mechanical / thermal loads, the rigidity of these films can largely modify and decrease, thus possibly affecting the mechanical capacity of the PV module, and even exposing the solar cells to fault. Knowledge of the effective bonding level is an important step for diagnostic purposes. In this regard, the present study is based on a preliminary non-destructive experimental analysis, and on an extensive parametric Finite Element (FE) numerical investigation of full-scale commercial PV modules of typical use in buildings. The attention is given – for PV module arrangements of technical interest – to the effect of EVA stiffness in terms of vibration modes and frequency sensitivity. As shown, especially compared to newly installed PV modules, any kind of stiffness decrease is associated to major frequency modifications for the composite system, and in the worst configuration, such a frequency scatter can decrease down to −40% the original condition. Such a marked stiffness decrease would be implicitly associated to a weak mechanical performance of the sandwich section, with major stress peaks and deflections in the PV system, even under ordinary loads. The presented results, in this sense, suggest that major consequences can be prevented and minimized by monitoring the vibration frequency of PV modules. [ABSTRACT FROM AUTHOR]

Energy extraction from ocean or wind currents through flow-induced vibration (FIV) of cylindrical structures is an important means of generating clean and renewable energy in nature. In this paper, we focus on investigating the response and energy harvesting performance of a semi-circular cylinder subjected to low- and high- Re (Reynolds number) cross-flow. Irrespective of Re , we observe six different types of FIV responses within the angle of attack (α) range of 0°–180°. Based on the characteristics of the vibration amplitudes and frequencies, these responses are categorized as typical VIV, extended VIV, narrowed VIV, galloping, combined response, and transition response. To assess the energy harvesting performance of these responses, we analyze the harvested power (P h) and efficiency (η h). Our findings indicate that in the VIV regimes, P h and η h are strongly dependent on the amplitude. However, an exception is noticed in the third branch of the extended VIV, where the amplitude is significantly large but P h and η h are small. In the galloping regime, the dependence of P h and η h on the amplitude becomes weak. Amongst all the response regimes, the galloping at α = 180° exhibits the best energy harvesting performance, with the highest η h reaching 46.5%. In the combined response, P h and η h are significantly small, regardless of whether it occurs in the VIV or galloping (or large-amplitude vibration) region. Further, we confirm the significant influences of the damping coefficient and mass ratio on the energy harvesting performance. By selecting the optimal damping coefficient and mass ratio, both P h and η h are significantly improved. [ABSTRACT FROM AUTHOR]

• Helical buckling of stranded wire ropes was extensively studied experimentally. • Numerical modelling was undertaken in Abaqus using an experimentally calibrated beam element. • Robust FE model of helical buckling of a non-homogenous slender shaft was developed. Helical buckling is very common in slender structures and it is characterized by the development of helical deformation patterns along their length. This phenomenon is particularly acute in very slender drill-strings as associated high stresses decrease drilling efficiency and shorten life expectancy of expensive drilling assemblies. Hence, understanding and predicting buckling behaviour is of paramount importance. In this paper, we investigated buckling phenomena of slender flexible shafts in forms of stranded wire ropes mimicking drill-strings, by experimental and numerical means. From experiments we obtained the loading curves for the flexible shafts and developed governing buckling equations using dimensional analysis. Based on these equations, we calculated the effective material properties of the stranded ropes and carried out FE modelling and analysis in Abaqus. Finally, we developed a robust method to predict the helical buckling behaviour, which matches well with experiment results. [Display omitted] [ABSTRACT FROM AUTHOR]

• The research conducted experiments on Condensation-Induced Water Hammer in WASIF. • In experiments, subcooled water injected radially into steam filled horizontal pipe. • Experimental results enhance CIWH triggering understanding in horizontal pipes. • A correlation predicts the necessary minimum feed water flow for CIWH initiation. • The study presents a regime map as a reference to prevent CIWH. Condensation-Induced Water Hammer (CIWH) phenomenon involves dynamic pressure changes caused by rapid condensation of steam in subcooled water. The magnitude of pressure spike is often large and can cause damage to the pipes and components in steam-water systems. Understanding the phenomena is vital for obtaining a safe and reliable design. This paper describes experimental investigations carried out in a specially designed facility called Water and Steam Interaction Facility (WASIF-I), that offers control over water and steam flow rates, can operate in co–, cross-, or counter-current flow mode and contains multiple injection locations. The occurrence of CIWH in horizontally oriented pipes filled with saturated steam is studied for the case where subcooled water is injected in cross-flow mode. The effect of geometrical and operating variables on the initiation of CIWH as well as peak pressure are brought out in this experimental work. A correlation to predict the critical minimum feed water flowrate necessary for triggering CIWH is developed based on multiple, nonlinear regression analysis of data from around 150 experiments. A regime map is presented that can be used as a guideline to preclude occurrence of CIWH. [ABSTRACT FROM AUTHOR]

Understanding the expansion mechanism of polyurethane polymer grout can supply guidance for accurate grouting. However, most of the polymer grout expansion calculations were defined simplistically by the polymer density-expansion pressure empirical relationship expression, which failed to meet the time history of the expansion pressure during the polymer reaction process. The objective of this paper was to investigate the expansion mechanism of polyurethane foam in various constraint conditions during the whole polymer reaction process. A model describing the expansion mechanism of polyurethane foam was established based on the energy conservation principle, the chemical reaction kinetic equation solved by the Runge-Kutta method, and the ideal gas state equation. The model was proved applicable compared to the experiments under fixed volume and fixed confining pressure boundaries. In addition, the effects of grouting quantity, confining pressure, initial temperature, and physical foaming agent content on the grout expansion pressure, density, and components conversions were discussed. The results showed that the expansion pressure of polymer grout gradually increased with time under the fixed volume conditions, and the grout expansion pressure increased as the density increased. The final grout expansion pressure will increase with the increase of initial temperature or the content of physical blowing agent. Under the fixed confining pressure condition, the polymer grout density gradually decreased with time, the grout density increased as the confining pressure increased while the conversions of the two components alcohol and isocyanate increased. The final density decreases with the increase of initial temperature or the content of physical blowing agent. [Display omitted] • Established a model describing the expansion mechanism of polyurethane foam. • Confirmed the model's applicability through experiments under fixed volume and pressure conditions. • Revealed the laws of grout expansion pressure, temperature, density, and component conversion. • Studied the effects of grouting quantity, confining pressure, initial temperature, and foaming agent content on expansion. [ABSTRACT FROM AUTHOR]

Progressive collapse can be triggered by impact loading from vehicles or other objects and propagated by impact loading from falling debris. Therefore, the correct modeling of impact loading is necessary to assess the resistance of a structure against progressive collapse. As the number of timber buildings increases, the importance of adequate considerations of impact loading is growing. Previous research on impact loading of wood or timber was carried out on small clearwood specimens or on single boards. However, modern timber buildings use advanced wood-based composites, such as glued laminated timber and laminated veneer lumber. The characteristics of these materials are widely different from clearwood and single boards. In this paper, energy-based equations are derived for the peak impact force and the dynamic strength increase factor. These are quantified by pendulum impact hammer tests on 95 full-size glued laminated timber beams. The results are applied in a calculation example to demonstrate their potential use in practice. • Energy-based models for impact loading of timber beams are presented. • Results from 95 impact tests on full-size timber beams are discussed. • High-speed imagery reveals the impact process and five distinct failure modes. • The energy-release properties of timber beams are found to be strength class independent. • The dynamic increase or load duration factor is found for impact loading of timber beams. [ABSTRACT FROM AUTHOR]

We show by extensive Monte Carlo simulations that we need a multi-spin interaction in addition to pairwise interactions in order to reproduce the temperature dependence of the experimental magnetization observed in the perovskite compound Pr 0.67 Sr 0.33 MnO 3. The multi-spin interaction is introduced in the Hamiltonian as follows: each spin interacts simultaneously with its four nearest-neighbors. It does not have the reversal invariance as in a pairwise interaction where reversing the directions of two spins leaves the interaction energy invariant. As a consequence, it competes with the pairwise interactions between magnetic ions. The multi-spin interaction allows the sample magnetization M to increase, to decrease or to have a plateau with increasing T. In this paper we show that M increases with increasing T before making a vertical fall at the transition temperature T C , in contrast to the usual decrease of M with increasing T in most of magnetic systems. This result is in an excellent agreement with the experimental data observed in Pr 0.67 Sr 0.33 MnO 3. Furthermore, we show by the energy histogram taken at T C that the transition is clearly of first order. We also calculate the magnetic entropy change | Δ S m | and the Relative Cooling Power (RCP) by using the set of curves of M obtained under an applied magnetic field H varying from 0 to 5 T across the transition temperature region. We obtain a good agreement with experiments on | Δ S m | and the values of RCP. This perovskite compound has a good potential in refrigeration application due to its high RCP. • Modeling using a multi-spin Interaction for Pr 0.67 Sr 0.33 MnO 3. • Unusual temperature dependence of the magnetization. • First-order phase transition using Monte Carlo energy histogram technique. • Large magnetic entropy change and high RCP. • Good agreement between modeling and experiments on above-mentioned properties. [ABSTRACT FROM AUTHOR]

The continuous decrease in feature size in the production of electronic chips has two major consequences for silicon wafers: (i) processing conditions for slicing and grinding operations need to be optimized and (ii) surface damage imposed by wafer handling and transport needs to be minimized. Cultivating a deeper understanding of the subsurface implications of contact, in particular during scratching, is necessary to achieve these goals. The active subsurface micro-deformation mechanisms, including phase transformations and crack formation, can only be measured post-scratch. On the other hand, numerical models are free of experimental constraints and can therefore serve an instrumental role in uncovering the active deformation mechanisms during scratching. However, model identification and validation with experimental data is essential for reliable simulation results. Therefore, in this paper, a numerical scratch model consisting of a continuum particle methodology combined with a large strain inelastic constitutive model is exploited, whereby the parameters are identified from indentation data. The numerical–experimental results are next compared for a range of micro-scratch tests. The experimental micro-scratch device was mounted inside a scanning electron microscope to perform in situ scratch experiments. The real-time observations at the scratched surface allowed to assess and exclude possible experimental artifacts. The simulations demonstrate the ability to investigate the evolution of the phase transformations underneath the scratched surface and relate this to the hydrostatic pressure. Notably, at the simulated subsurface phase boundary, hydrostatic tension was found which is expected to play an important role in median crack formation, as often reported in the literature. For the simulation and experiments, the steady-state segments are compared and it was found that the model accurately reproduces the substantial surface recovery due to the Si-II → Si-a phase transformation. Additionally, the simulated and experimental surface cross-sectional profiles for normal scratching loads of 30, 40 and 50 mN are in adequate agreement. • Newly developed silicon micro-scratch model used for scratch simulations with a blunt tip. • In situ imaging of micro-scratch tests to identify experimental artifacts. • Quantitative comparison between simulated and measured post-scratch surface topologies. • Close resemblance between experiments and simulations for the cross-sectional profiles for scratches at 30 and 40 mN normal load. • Modeled Si-II to Si-a transformation is crucial for accurate simulation results. [ABSTRACT FROM AUTHOR]

Low carbon urban transition experiments are emerging across cities globally. These experiments are socio-technical innovations with a high potential to contribute to a low carbon. Through the Global Intelligence Corps knowledge of these experiments is being disseminated across a variety of spatial contexts. Foreign cities are keen to replicate these examples of best practice; whilst technical experts, technology providers and governments are keen to export their expertise and technologies. However, the factors influencing the successful translation - movement, transformation and adaptation - of these experiments across spatial contexts requires deeper investigation. This paper explores the process using a mobile transitions conceptualisation. In this paper we develop a theoretical conceptualisation of the mobile transition process and test it using two low carbon experiments - Hammarby Sjostad (Stockholm) and BedZed (London). We identify the type of knowledge that is translatable (in the global form), and how this is modified both by the global and local assemblages throughout the process. The implication of our findings is that greater clarity is needed throughout the translation process if outcomes are to improve. Firstly, in order to determine the potential for an urban experiment to translate into a new spatial context the practitioner must understand the context from which it emerged and the context into which it will be translated. Secondly practitioners need to clearly define the translatable global form emerging from an experiment. It must be possible to decontextualise and re-contextualise the global form if it is to translate successfully. In some cases it may be impossible to decontextualise the global form without undermining the fundamental principles underlying the experiment. Thirdly, practitioners need to be aware of how the global form can be manipulated and re-represented by the global and local assemblages during the translation process. The global form is not fixed. Finally practitioners should be aware that new socio-technical systems (adopting the fundamental principles developed in the experiment) will emerge from the translation process. [ABSTRACT FROM AUTHOR]

In the frame analysis, the local analysis model of the joint must follow the behavior of the joint. When completing the elastic global analysis, the initial rotational stiffness of the joints should be known to obtain the reliable moment distribution between the members of the frame. This paper evaluates the existing calculation approach for the initial rotational stiffness of welded rectangular hollow section T joints. Validation with the experiments shows that the current calculation approach significantly underestimates their initial rotational stiffness. Based on the existing experimental data, the paper proposes the improvement for determining the initial stiffness. The second part of the article investigates the effect of the axial force in the main member on the initial rotational stiffness of the joint. The conducted numerical study on square hollow section T joints shows that the reduction of their initial stiffness can reach 50%, when the main member experiences the normal stresses close to yielding. Using the curve fitting approach, the paper proposes and validates a corresponding chord stress function, similar to the existing ones for the moment resistance. [ABSTRACT FROM AUTHOR]

A select number of scientific communities have been quite successful in evolving the culture within their community to encourage publishing and to provide resources for re-using well-documented data. These data have great potential for analysis and knowledge generation beyond the purposes for which they were collected and intended. However, there are still barriers in this process. To explore this problem, we have developed a prototype tool: the Experiment Dashboard (ED), with the objective of demonstrating the ability and potential of enabling automated data ingestion from typical research laboratories. This innovative prototype was developed to create a novel system and artifact to explore the possibilities of allowing researchers in laboratories across the nation to link their data acquisition systems directly to structured data repositories for data and metadata ingestion. The prototype functions with commonly used data acquisition software at the data source and the HUBzero scientific gateway at the data sink. ED can be set up with minimal effort and expertise. In this paper, we describe the motivation and purposes for the prototype, the architecture we devised and functionality of this tool, and provide a demonstration of the tool for optical measurements in a structural engineering laboratory. The goal of this paper is to articulate and show through our prototype a vision for future cyberinfrastructure for empirical disciplines that rely on the rapid collection, analysis, and dissemination of valuable experimental data. We also discuss lessons learned that may be useful for others seeking to solve similar problems. [ABSTRACT FROM AUTHOR]

Brittle fracture of asphalt binder is studied in this paper at low temperatures and under mixed mode crack tip deformation. A set of fracture tests are conducted by two new laboratory specimens made of a type of asphalt binder. The suggested specimens can provide pure mode I (opening), mixed mode I/II, and pure mode II (sliding) crack propagation conditions. The crack propagation angles and fracture toughness values were measured from experiments under pure mode I, pure mode II and mixed mode I/II conditions. The experimental results were then evaluated using different fracture criteria: strain energy density (SED), maximum tangential stress (MTS), and maximum tangential strain (MTSN). The role of the first non-singular term of the elastic stress and strain field (generally called T-term) on the predictions provided by each criterion is discussed. It was found that both specimens are significantly affected by the T-term, and adding T-term significantly improves the predictions provided by each criterion. It was shown that for the mixed mode conditions, the strain-based criteria provide better predictions for the fracture toughness than stress-based and energy-based criteria. The results of this paper will help researchers to understand the mechanism of mixed mode crack propagation in asphalt binders, and as a result in pavement structures, at low temperatures. [ABSTRACT FROM AUTHOR]

Models help us understand, assess, predict; but they are limited, uncertain. To better understand limitations and uncertainties due to scale effects in model test experiments of wave energy converters (WECs), we conducted a series of experiments at three model scales of a case study oscillating-water-column (OWC) WEC. This paper reports incident waves, power, and loads results across scales, and evaluates the causes and effects of identified scale-dependent parameters. Incident wave profiles varied significantly across scales as they became more nonlinear. These nonlinear wave variations caused and interacted with scale effects associated with capture width ratio and loads, which showed moderate-significant differences across scales (10–30%+). Larger models tended to show relatively higher power performance and loads. Key scale-dependent parameters likely contributing most to differences in results across scales were associated with the test environment (incident wave generation and nonlinear waves), the model (deployment position relative to the wavemaker and PTO modelling), and instrumentation and apparatus (force balance). Interacting nonlinearities between waves, OWC hydrodynamics, and power take-off damping exacerbated observed scale effects. Thus, scale effects can be significant and should be accounted for in model test experiments of WECs. Doing so will likely improve experimental outcomes and, hence, a WEC's commercial viability. [ABSTRACT FROM AUTHOR]

The laboratory for renewable energy sources of the Higher Education Technical School of Professional Studies in Novi Sad (Serbia) contains the equipment regarding solar and thermal techniques, based on the implementation of solar panels, heat pumps and a pellet stove. Photovoltaic systems include the implementation of static photovoltaic panels, trackers and inverters for power supply of autonomous consumers. In addition, the laboratory is equipped with modern systems of internal and external lighting, a wind generator with accompanying inverter, elements of smart installations and fuel cell systems for laboratory measurements. This paper presents experiences in the implementation of the photovoltaic systems in the educational process through laboratory exercises. The specification of the laboratory equipment, the methodology of work, as well as the electrical schemes of experiments of open circuits and short circuit, recording of electricity-voltage characteristics, tracking the maximum power point, serial and parallel connection and shading of photovoltaic cell are presented. The second group of the trial is performed on the "off grid" photovoltaic system set in the schoolyard and connected to the appropriate inverter with the autonomous group of consumers. The paper presents the results of laboratory measurements, issues for discussion, evaluation of the performance and conclusions. [ABSTRACT FROM AUTHOR]

A fraction-order total variation blind image restoration algorithm based on L1-norm was proposed for restoring the images blurred by unknown point spread function (PSF) during imaging. According to the form of total variation, this paper introduced an arithmetic operator of fraction-order total variation and generated a mathematical model of cost. Semi-quadratic regularization was used to solve the model iteratively so that the solution of this algorithm became easier. This paper also analyzed the convergence of this algorithm and then testified its feasibility in theory. The experimental results showed the proposed algorithm can increase the PSNR of the restored image by 1 dB in relation to the first order total variation blind restoration method and Bayesian blind restoration method. The details in real blurred image were also pretty well restored. The effectiveness of the proposed algorithm revealed that it was practical in the blind image restoration. [ABSTRACT FROM AUTHOR]

In the part I of the paper, a temperature effect was experimentally observed for the relative humidity measurement. This effect was correlated to the temperature dependence of the sorption isotherm. In this part II of the paper, the influence of this temperature dependence is investigated on the simulated hygrothermal behavior of hemp concrete. Sorption isotherm was modeled through three approaches: a unique curve (like in WUFI), a temperature-dependent GAB model or the Clapeyron equation associated to the isosteric heat of sorption evaluated in the part I of the paper. Comparison between simulation and experiment is performed for the sample presented the part I of the paper and for a wall subjected either to a slow temperature decrease toward 0 °C or to a fast temperature increase due to solar radiation. Whatever the investigated case, results underline that accounting for the temperature dependence improve the relative humidity prediction. Nevertheless, a great sensitivity to the modeling approach and to the input parameter was observed. [ABSTRACT FROM AUTHOR]

This paper is dedicated to creep buckling predictions. Thin walled cylinders having an aspect ratio of one are subjected to an uniform external pressure. The material is a special type of nickel which “creeps” at ambient temperature. The material parameters for the creep law are identified from experimental results. The creep failure experiments are described and corresponding failure times are given. The paper then compares three alternatives of finite element modeling of the experiments (3D Shell with integration through the thickness with a periodic or non periodic initial imperfection are compared with COMU quasi axi-symmetric imperfect shell element). These 3 modeling show consistent predictions. The simulation time is a hundred times faster with the COMU model. It is shown that the prediction of failure time of these experiments is extremely sensitive to the initial imperfection amplitude. The effect of creep law modeling is also important. Finally a parametric analysis on different types of cylinders is given: some general trends are proposed for this type of delicate predictions. [ABSTRACT FROM AUTHOR]