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Abstract: In this paper, we present an experimental study on measurement of the thermal conductivity and heat pipe effect in both hydrophilic and hydrophobic (Toray TGP-H60) carbon papers (around 200μm thickness) with/out liquid water. An experimental setup is developed for measuring thermal conductance at different liquid water contents and temperatures without dissembling the testing device for water addition. Theoretical analysis is also performed to evaluate the apparent conductance of heat pipe effect. We found that liquid water presence inside these materials increases the overall thermal conductivity. At high temperature around 80°C, the heat pipe effect is evident for the hydrophilic paper; while for the hydrophobic one, the heat pipe effect is found to be smaller. The distinction is likely due to the different patterns of the capillary liquid flow in the two media. For the hydrophobic paper, liquid water flows back to the evaporation side when the breakthrough pressure is reached and flow is through preferred routes of small flow resistance. As a result, heat pipe effect is active only in part of the medium, therefore smaller than that in the hydrophilic one. The results are important for understanding the heat transfer phenomena occurring in porous media and effects of material surface property. [Copyright &y& Elsevier]

The Rentier State Hypothesis states that taxation promotes government accountability. The argument is that citizens demand more accountability for spending of tax revenue than for spending of windfall revenue (e.g., natural resource revenue and aid). This paper presents causal evidence from a between-subject experiment that tests the effect of taxation on demand for accountability. To investigate the underlying mechanisms of the effect, the design focuses on two main features that distinguish tax from windfall revenue: Tax revenue is produced by citizens' work and has been in their possession before it is collected as tax. The main finding is that taxation causes a higher demand for accountability when both features of taxation are present, consistent with the Rentier State Hypothesis. The paper sheds light on the political economy of government revenues, and contributes to our understanding of how features of the tax system shape behavior. [ABSTRACT FROM AUTHOR]

Over the past century, the scientific conception of the protein has evolved significantly. This paper focuses on the most recent stage of this evolution, namely, the origin of the dynamic view of proteins and the challenge it posed to the static view of classical molecular biology. Philosophers and scientists have offered two hypotheses to explain the origin of the dynamic view and its slow reception by structural biologists. Some have argued that the shift from the static to the dynamic view was a Kuhnian revolution, driven by the accumulation of dynamic anomalies, while others have argued that the shift was caused by new empirical findings made possible by technological advances. I analyze this scientific episode and ultimately reject both of these empiricist accounts. I argue that focusing primarily on technological advances and empirical discoveries overlooks the important role of theory in driving this scientific change. I show how the application of general thermodynamic principles to proteins gave rise to the dynamic view, and a commitment to these principles then led early adopters to seek out the empirical examples of protein dynamics, which would eventually convince their peers. My analysis of this historical case shows that empiricist accounts of modern scientific progress—at least those that aim to explain developments in the molecular life sciences—need to be tempered in order to capture the interplay between theory and experiment. [ABSTRACT FROM AUTHOR]

• Different configurations of TEM were tested in this research. • 6-Jointed TEM provided around 100% higher COP in the same power input. • A comprehensive sensitivity analysis was carried out for 6-jointed mode. • Perforation technique was employed to further enhance the COP. • Spring wire was used to further improve the COP of the cooler. Although individual commercial thermoelectric module has been widely investigated and its cooling behavior is clear, jointed thermoelectric modules show completely different cooling behavior and higher coefficient of performance (without the change of input electrical power) which requires further study. At the first step of this research, cooling characteristics of 2-jointed, 4-jointed and 6-jointed thermoelectric modules are experimentally evaluated and discussed under the same range of input electrical power. In the same total input electrical power, 6-jointed TEM (thermoelectric module) provided around 100% higher COP (coefficient of performance) than the 2-jointed TEM which was significant. Cooling behavior of different-number jointed TEM (in the same input power) are analyzed and discussed in this paper. In the second step of this research, the COP of 6-jointed TEM cooler (selected from the first step) has been increased again by proposition of two new techniques based on the modification of the popular rectangular-fin heat sink. Attempts are made to further enhance the COP of the system by two methods including "perforating technique" and "spring wire technique" through a Peltier air cooler which have not been proposed before. In the same electrical power input, perforating technique enhanced the thermal performance of the Peltier air cooler around 50% (totally 150% compared to the 2-jointed TEM with simple heat-sink) and the use of spring-wire between the fins of heat-sink improved the COP around 130% (totally 230% compared to the 2-jointed TEM with simple heat-sink). Exact explanation of the quality/quantity and improvement reasons of each technique are described in this paper for different working conditions of the cooler. [ABSTRACT FROM AUTHOR]

The impact of culture on non-kin cooperation has been singled out as critical for economic activity. However, causal evidence of culture's influence on cooperation remains scant. In this paper we provide such evidence, focusing on two key components of culture: preferences and beliefs. Adopting the view that culture is one aspect of an individual's multi-faceted self-concept (identity) we conduct a Prisoner's Dilemma experiment with first- and second-generation Chinese immigrants at a large US public university. In a two-by-two design, we exogenously vary: i) the salience of participants' American or Chinese cultural identities; and ii) the capacity for culture to affect beliefs by randomly providing previous-session cooperation-rate information. Comparing behavior across cultures and information conditions, our results suggest a prominent role for both preferences and beliefs. [ABSTRACT FROM AUTHOR]

• We propose a new estimator of the Democracy Effect that overcomes selection effects. • It weighs the behavior of each type of voter by its prevalence in the whole population. • We derive the distribution of this new weights-based estimator of the democracy effect. • Applications to two experiments find a significant effect in one but not the other. Dal Bó et al. (2010) show experimentally that the effect of a policy may be greater when it is democratically selected than when it is exogenously imposed. In this paper we propose a new and simpler estimation strategy that does not require information on the vote of subjects in the exogenous treatment. The new estimation strategy is based on calculating the average behavior under democracy by weighting the behavior of each type of voter by its prevalence in the whole population (and not conditional on the vote outcome). We derive the distribution of this new weights-based estimator of the democracy effect and show it eliminates selection effects under certain conditions. We apply the new estimation strategy to the data in Dal Bó et al. (2010) and to the data from a new experiment for which we cannot use the previous estimation strategy as we do not have information on how subjects would have voted in the exogenous treatment. We find a significant democracy effect in the former but not on the latter application. [ABSTRACT FROM AUTHOR]

• The positive pressure condensation dehumidification method for humid air is proposed. • The heat and mass transfer model of the new dehumidification process is developed. • Condensation dehumidification experiments with different pressures are carried out. • Heat and mass transfer rate is about 3 times higher than that at atmospheric pressure. • Air humidity after dehumidification is less than half of that at atmospheric pressure. Air condensation dehumidification is the main dehumidification method, which dehumidifies by cooling the air temperature below its dew point temperature. The process of atmospheric condensation dehumidification requires chillers to obtain lower temperature cooling sources, which leads to reheat loss. In this paper, the positive pressure condensation dehumidification method for humid air is proposed, as the dew point temperature of air is increased with the pressure. By this way, natural cooling sources or evaporative cooling towers can be used instead of refrigeration systems for cooling and dehumidification. The heat and mass transfer model of the positive pressure condensation dehumidification process for humid air is developed, which has three parts: single droplet part, droplet growth part, and single tube condensation part. Positive pressure condensation dehumidification experiments with different pressures are carried out, and experimental results show that the model accuracy is within ± 10 %. Additionally, theoretical results indicate that the heat and mass transfer rate within the pressure range of 160–290 kPa is about 2.5–3.4 times higher than that at atmospheric pressure, and the humidity of the air after dehumidification is 15.6–10.9 g/kg, which is less than half of that at atmospheric pressure. [ABSTRACT FROM AUTHOR]

• An effective mathematical model for bolted flange joints is proposed. • The proposed model is applicable for both bolt looseness and no-looseness conditions. • Experimental results validate the proposed model. • The soft nonlinearity characteristics of bolted flange joint multi-plate structure under base excitation are revealed. Bolted flange joints are widely used in various engineering structures to combine two or more substructures together. However, the understanding of mechanical mechanism of bolted flange joints is still insufficient due to the lack of efficient mathematical models. This paper proposes an effective mathematical model for bolted flange joints, which is then employed to conduct vibration analysis on bolted flange joint multiple-plate structures. During the modeling process, the flange is modeled by the Kirchhoff plate theory, and the bolted joints are modeled by the two-dimensional face constraint in bolted joint affected region (BJAR). The artificial spring technique is adopted to simulate the face constraint. The friction contact model and equivalent linearization technique are adopted to analyze the stick and slip states of bolted joints. By adopting the Chebyshev orthogonal polynomials as admissible functions, governing equations are derived. Then, the Rayleigh-Ritz method is applied to study the free vibration characteristics, and the Newmark-beta method is employed to study the vibration response under base excitation. The experimental studies are performed on the bolted flange joint two-plate structure (BFJTPS) to illustrate the effectiveness of the proposed theoretical model. The results indicate that the proposed mathematical model can well predict the vibration characteristics of multiple-plate structures under both bolt looseness and no-looseness conditions. The soft nonlinearity phenomenon under bolt looseness condition can be successfully revealed by the model. [ABSTRACT FROM AUTHOR]

• The dynamic model of the two-span rotor-bearing-pedestal system is established. • A fault characterization model of raceway extension defects is proposed. • The influence of misalignment on bearing defect fault is further discussed. • The system dynamic characteristics during bearing defect extension are analyzed. When the rolling bearing raceway is tilted, the contact load of the raceway increases, which may greatly increase the occurrence of raceway defects. However, the evolution law of the raceway defect extension process on the system dynamic characteristics is not clear when the bearing is tilted. In this paper, considering the influence of rough surface caused by the extension of bearing defects, a mathematical model of raceway extension defects which is more consistent with the actual morphology is proposed. The model can be used to evaluate the damage degree of the bearing raceway of rotating machinery. Taking the two-span rotor-bearing-pedestal system of the test rig as the research object, a nonlinear dynamic model of the system is established considering the nonlinear supporting force of bearings and pedestal, shaft coupling looseness and other nonlinear factors. The effectiveness of the bearing fault characterization model and the system dynamics model is verified by experiments. On this basis, the influence of tilt on bearing fault and the change rule of raceway defect extension on bearing contact characteristics and system dynamic characteristics are discussed. The results indicate that raceway tilt aggravates system vibration caused by the bearing defect. With the increase of the defect range, the impact vibration characteristics weaken, and the roughness of the raceway surface in the defect area has a great influence. However, with the increase of defect depth, the influence law is just the opposite. The research results are expected to provide theoretical support for bearing fault diagnosis of rotating machinery systems. [ABSTRACT FROM AUTHOR]

The hydrogen and oxygen bubbles covering the electrode surface will reduce the reaction rate of water electrolysis and increase energy consumption. Adding ultrasonic to the electrolytic cell can improve the escape velocity of bubbles on the electrode surface by oscillation and cavitation effect. In this paper, the effects of ultrasound on the performance of water electrolysis under different working conditions are studied by experiment and numerical simulation. Firstly, the polarization curves and bubble flow patterns under different positions of the ultrasonic vibrator and electrode were obtained through experiments. And then, the flow model of the electrolytic cell with ultrasonic is constructed, which considers the mass transfer between the gas and liquid phases and the acoustic flow phenomenon caused by cavitation. The results revealed that, due to the reflection of the wall and the transmission process of the ultrasonic in the electrolyte, the electrode position has a significant impact on the current density when the ultrasonic vibrator is located on the right side of the electrolytic cell, which can be increased by 2.40%–22.70% at different electrode positions compared with that without ultrasound. The influence of operating parameters on the flow field inside the electrolyzer was obtained through numerical simulation. As a result, appropriate loading methods and operating conditions can maximize the effectiveness of ultrasound. [Display omitted] • Improper ultrasonic loading method increases energy consumption. • Wall conditions have a significant impact on the performance of water electrolysis. • The bubble flow morphology on the electrode surface was observed. • A flow field model of electrolyzer with ultrasonic was constructed. [ABSTRACT FROM AUTHOR]

Agglomeration of fine particles is an essential procedure to improve separation efficiency of dust-removal devices. This paper focuses on the treatment of biomass Micro-Nano particles using cascade electrostatic and magnetic fields. A carefully designed wind tunnel is built to investigate the agglomeration performance of pre-charged Micron-Nano particles (0.016–9.84 µm) in uniform magnetic field. The influence of supply voltage (10–30 kV) in the electrostatic unit and the bulk flow velocity (1–5 m/s) across the device upon agglomeration is studied. The results indicated noticeable agglomeration behavior because of reduced submicron particles and increased larger particles. Strengthening Supply voltage input has a positive yet minimum effect on the overall agglomeration efficiency. Effect of bulk flow velocity on agglomeration is remarkable due to magnetic field. Therefore, agglomeration of pre-charged particles in uniform magnetic field is dominated by Lorentz effect and stream-wise spacing of the device. This work provides a reference for further computational attempt in the future. [Display omitted] • Agglomeration of biomass Micro-Nano particles can be realized with proposed method. • Supply voltage of the electrostatic unit has minimum influence upon agglomeration. • Effect of bulk flow velocity on agglomeration is remarkable due to magnetic field. [ABSTRACT FROM AUTHOR]

The development of the relay protection based on open architecture is a relevant direction of electrical and electronic engineering. The paper presents the problem of the modern microprocessor-based relay protection that consists in the impossibility of the element replacement with alternatives from other manufacturers. The literature review on the reed switches application for relay protection, traditional and open-source solutions are given. Τhe structural scheme of the processes and relay protection device with different modules and the use of open-source communication and Industrial Internet of Things is demonstrated. The goal of the further research of sensibility, selectivity and reliability is set. [ABSTRACT FROM AUTHOR]

• Energy-based formulation of delamination by a quasi-static evolutionary process. • Enhanced formulation of the delamination model using an interface damage variable. • Experimental verification by the interlaminar stiffness test for Mode I delamination – DCB Test. • Providing the best experimental estimate to the stress–strain relation in the computational model. The paper presents methods and procedures of computational and experimental approach of modeling and analysis of problems with Mode I delamination. One of the main goals of the work is to focus on the interface between anisotropic materials in a computational model and its consideration under stress. The paper presents a numerical method for the prediction of a damaged interface based on a variational formulation that is implemented using the symmetric Galerkin boundary element method. The calculation part consists of interface analysis considering the cohesive type of contact. The damaged interface between anisotropic domains is analyzed under loading in Mode I. Stress, deformation quantities and damage are calculated using methods of nonlinear programming. The experimental evaluation of the Mode I delamination is presented in a comparison with the values obtained from the computations. The experience and recommendations related to the use of carbon fiber reinforced polymer composite materials are presented. [ABSTRACT FROM AUTHOR]

The Near-Space Plasma Electromagnetic Science Experimental Research Apparatus is designed for ground-based simulation of plasma sheath and is capable of providing pure, high-enthalpy, and high-density plasma jets. The high enthalpy implies a high plasma state, which can achieve high Mach equivalent simulation in flight conditions. This paper takes this device as the research object and establishes a multi-physics coupling magnetohydrodynamics model to simulate the heat transfer process under high-power conditions. Through numerical simulation, the distribution rules of plasma temperature and enthalpy value under different power states considering the radiation source are obtained. By combining numerical simulation with experimental verification, the simulated enthalpy and energy conversion efficiency results are compared with experimental data, showing good consistency. The study finds that the enthalpy at the center of the jet outlet is higher, increasing from 5.4 MJ/kg to 9.5 MJ/kg when the high-frequency power increases from 150 kW to 426 kW, with an increase of 4.0 MJ/kg. The overall distribution of plasma jet enthalpy exhibits a central peak, gradually decreasing radially from the center to both sides. Meanwhile, during the axial jet injection process, there is a transition in the radial distribution of temperature and enthalpy, shifting from a saddle-shaped distribution at the coil position to an arch-shaped distribution at the nozzle outlet. In this power range, the energy conversion efficiency of the high-frequency power source ranges from 53% to 30%, with both calculated and measured efficiencies decreasing with increasing power. Additionally, the paper discusses the impact of radiation source terms on the distribution of enthalpy in high-power inductive-coupled plasma. In conclusion, the model proposed in this paper can be used to estimate the outlet enthalpy distribution and energy conversion efficiency of the Near-Space Plasma Electromagnetic Science Experimental Research Apparatus, providing data support for the design, control, and application of the device. • Develops model for simulating plasma heat transfer in high-power settings. • Enthalpy & efficiency simulation aligns well with experiments. • Model predicts device's outlet enthalpy distribution, aiding control and application. [ABSTRACT FROM AUTHOR]

• The values of the recovery heat flux at superfluid helium boiling is differ from immersion depth and liquid temperature. • There is no influence permeability on the recovery heat flux at backfill particles diameters greater than 240 µm. • The calculated results are in satisfactory agreement with the experiment. • Porous insert has a significant effect on the interface dynamics\ (amplitude, frequency, stationary vapor film). The paper presents experimental data on the recovery heat flux during the boiling of superfluid helium (He II) on a flat heater located inside a U-shaped channel. The lower part of the channel is filled with monodisperse porous backfill. The paper includes information on the experimental cell, the data processing and synchronization technique, and the results of experiments conducted at different heater immersion depths and liquid temperatures. The paper presents also a mathematical description of heat transfer processes in superfluid helium for confined conditions. The calculated values are compared with experimental data. The effect of the porous backfill permeability on the recovery heat flux, including the case of a free channel is discussed. It is demonstrated that the increase in the heat flux in the channel initiates oscillations of the phase interface. [ABSTRACT FROM AUTHOR]

This paper presents a novel strategy to download higher data volumes from space stations. To demonstrate this approach, the communication link between the international space station (ISS) and the U.S. tracking and data relay satellite (TDRS) system is considered. The proposed solution relies on multiple-antenna technology, so-called multiple-input multiple-output, that can provide added capacity gain if the antenna elements match a precise geometry. The analysis shows that two colocated TDRSs can lead to a capacity increase by a factor of 1.8 per polarization per satellite. We compare this approach to other enhancement strategies. This study shows that the proposed solution presents the best trade-off in terms of capacity increase, link availability, redundancy and system changes. Thus, this paper provides a novel perspective on potential future space data relay, which leads to high benefits in the near term to customers like the ISS and the high data volume required from the on-board scientific experiments. • A data-relay solution based on multiple-antenna space communications is proposed. • The proposed system is thoroughly studied for the international space station. • A colocated satellites system leads to the best trade off compared to other systems. • The data volume can be increased by nearly a factor 4 with minimal system changes. [ABSTRACT FROM AUTHOR]

Following paper presents an experimental study on eight potential plate materials for evaporative air coolers. There are three groups of materials: currently used plate materials (kraft papers), new natural origin plate materials (cotton fibers), and new synthetic plate materials (synthetic fibers). Proposed materials were examined in terms of different properties such as upward and downward distribution height, water capacity, durability and diffusivity. The results were compared with data presented by other authors. It was established that, synthetic materials are characterized by superior water distribution qualities in comparison to the materials of natural origin. Basalt paper-like synthetic fiber allowed to rise water vertically to 40 cm during 120 min tests. The highest water rise obtained in other studies was 18 cm, hence basalt paper-like fiber is visibly superior in comparison with the currently known materials. In terms of downward water distribution, two new synthetic surfactant non-wovens show better performance than the existing materials by quickly and evenly distributing water over the entire length of the sample. The durability of synthetic fibers and non-wovens is higher comparing with the materials of natural origin. The results show that synthetic materials are better suited to the role of plate materials in evaporative air coolers. • Experimental tests of eight potential plate materials for evaporative coolers • The tests include upward and downward water distribution, diffusivity and durability. • New materials show visibly higher performance in terms of most effectiveness factors. • Synthetic materials are confirmed to be most promising for evaporative coolers. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of the seismic performance of austenitic stainless steel full-scale frames using the pseudo-static test method. The bottom single-span, two-storey substructure of the designed prototype frame was chosen as the test frame. Two full-scale frames were tested, one with a bolt-welded joint and the other with an extended end-plate joint. This paper is the first of two accompanying papers to this experimental study and focuses on the specimen design, testing details and global response of the stainless steel frame under cyclic loading. The test results were utilized to analyse the global response of the frames, encompassing failure mode, bearing capacity, deformation capacity, energy dissipation capacity, the overstrength factor, ductility factor and seismic response modification factor. The experimental findings suggest that the stainless steel frames with two joint types demonstrate consistent ability to dissipate energy during cyclic loading. The structure also performs well in terms of deformation, with uniform inter-storey deformation and no soft-storey detected. The maximum storey drift ratio of the frame is 7%. Prior to reaching a storey drift ratio of 2%, the frames with both joint types exhibit similar cumulative plastic deformation, stiffness degradation, and cumulative energy dissipation. • Two stainless steel full-scale frames were tested under two loading protocols. • Global seismic response of the tested frames was analyzed. • Acoustic emission monitoring technique was attempted for overall damage detection. • Overstrength, ductility and seismic response modification factors were calculated. [ABSTRACT FROM AUTHOR]

This study proposed a procedure to optimize the mixture proportion of geopolymer using machine learning (ML) and multi-objective optimization (MOO) model, which enhances the compressive strength and minimizes the carbon emission and costs. The experiment was preliminary carried out to analyze the workability, compressive strength, microstructure, and pore characteristics of fly ash/slag-based geopolymer. The results showed that the higher replacement ratio of slag established positive effects on the hardening as well as porosity improvement due to the coexistence of C-S-H and NASH-type binders, especially for a ratio was no more than 60%. Considering the performance of geopolymers is often influenced by multiple factors such as material composition and curing conditions, which could not be solved by traditional methods. A database containing 836 samples was established to analyze the prediction performance of 7 ML models by using Bayesian optimization. The GPR model has good generalization ability, with R 2 being 0.99 (0.99) on the testing set (training set). Furthermore, the reliability of the ML models was evaluated by the tests conducted in this paper. The feature importance analysis utilizing SHAP method indicates that Age, HM, and SS are key parameters influencing the compressive strength of geopolymer. The proposed MOO model can effectively evaluate the trade-offs between compressive strength, carbon emission, and costs, and all Pareto solutions for bi-objective and three-objective provided the optimal mixture schemes. On this basis, the design procedure proposed in this paper can give the scheme of geopolymer materials with different requirements (given mixture scheme and given design strength). [Display omitted] • Working mechanism of different matrix on geopolymer are revealed. • SHAP method can explain the physical mechanism of parameter on the output variable. • Reliability of the intelligent prediction model is validated by experiment. • MOO model can evaluate the relationship between CS, CO 2 and costs of geopolymer. • Procedure of geopolymer mixture schemes with different design strength are proposed. [ABSTRACT FROM AUTHOR]

Large waves used to cause a lot of ship collapse accidents, resulting in the loss of many lives and property. The response of ships to collapse, including plasticity and buckling, has aroused focused concern among researchers. This paper carries out a hydroelasto-plastic experiment and numerical investigation of a three-cabin ship model to study its structural collapsed response. Firstly, a hydroelasto-plastic model experiment is conducted in a wave tank. A three-cabin experimental model which is made of stiffened plate, has been designed and manufactured. Then the model is forced to collapse in tank waves with measuring wave elevation, wave pressures, structural stress and rotational deformation of model. Secondly, a hydroelasto-plastic numerical approach coupling of CFD (Computational Fluid Dynamics) and nonlinear FEM (Finite Element Method) is used to co-calculate the wave loads and structural collapsed response of a ship model. A hydrodynamic model is constructed and utilized to solve wave loads in the CFD platform, while a nonlinear FEM model of the three-cabin structure is also constructed and solved using a nonlinear FEM solver to obtain the structural collapse response. Finally, hydroelasto-plastic experimental results and numerical results are compared and analysed, the structural collapsed characteristics of the three-cabin structure, which is very similar to a ship structure, are analysed. The numerical approach of two-way coupling of CFD and nonlinear FEM is verified for the hydroelasto-plastic problem. In this paper, the water elastic-plastic test of stiffened cabin structure under wave action is carried out, which provides a new perspective for ship structural design. [ABSTRACT FROM AUTHOR]

This paper studies the empirical properties and identification for a broad class of adaptive learning models in games (e.g., experience-weighted attraction (EWA), payoff assessment, and impulse-matching models). I first show that adding a constant c ≠ 0 to the utility function could affect players' choices during the learning periods. This property is different from standard theories, such as expected utility theory and discrete choice models, where adding c ≠ 0 preserves the same choice. This result has two further implications. First, the constant c added to the utility function could have a structural interpretation, and this paper discusses how to interpret it. Second, the estimation of learning models usually normalizes the utility of one action profile to be zero (i.e., c = 0); for instance, the utility of zero dollars is zero, as commonly imposed in experimental economics. This normalization is innocuous in most applications of discrete choice models but could be misspecified in the context of learning. To deal with the above issue, this paper proposes to specify a player's utility as an unknown function of the action profile, without imposing the above normalization. Equivalently, c is specified as an unknown parameter to be estimated. Under weak conditions, I obtain the joint identification of both utility and learning parameters. Finally, I illustrate the importance of c in the estimation of learning models by conducting a Monte Carlo experiment and revisiting the experimental study by Feri et al. (2010). [ABSTRACT FROM AUTHOR]

Hydraulic experiments using physical scale models of monopile scour protections typically have high experimental uncertainties and data scattering. These uncertainties may severely affect the accuracy of the experimental results and need to be analysed quantitatively. This paper presents a study on the quantification of experimental uncertainties in monopile scour protection damage tests following the Guide to the expression of Uncertainty in Measurement (GUM) (ISO, 2008). The uncertainty analysis is performed using the three-dimensional damage number S 3 D and the widely applied S T A B number. Through the analysis of the S 3 D number from individual test and repeated tests, it is found that the uncertainty analysis method for an individual test can be efficiently applied to predict the experimental uncertainty. The wave peak period and the current velocity are identified as the two major sources of uncertainties for the S 3 D number. The flow turbulence and correlations between input parameters can be neglected when estimating the uncertainty. The uncertainty analysis of the S T A B number shows that the experimental uncertainty due to measurement can be up to 5% to 7% of the obtained S T A B result. This uncertainty range is wide in comparison with the narrow margin of a dynamic scour protection design in DNV's recent recommended practice (DNV-RP-0618). The uncertainty of the S T A B number is more affected by the armour stone density, wave peak period and significant wave height. • Uncertainty analysis performed for monopile scour protection experiments. • Uncertainty analysis based on S 3D and STAB numbers. • Individual test and repeated tests yield similar S 3D uncertainty level. • Influences from various test parameters investigated. • Wide STAB parameter uncertainty range observed. [ABSTRACT FROM AUTHOR]

This paper reports a laboratory experiment that provides insights on cooperation in R&D investment when knowledge sharing decisions are endogenous. Specifically, there are two types of treatments: one in which participants decide on whether to share knowledge before they make their investment decisions and one where the knowledge sharing constellation is exogenously given, both with and without non-binding communication. The results show that there are behavioral spillovers between the decisions on knowledge sharing and investment. When exogenously set, the degree of symmetric knowledge sharing does not affect cooperation. Communication increases cooperation more when participants can decide on knowledge sharing. [ABSTRACT FROM AUTHOR]

Based on the self-deforming blade model and the related wind tunnel test platform, the experiments with synchronous deformation and pitch of the blade were carried out to simulate the operating condition of the blade on the vertical axis wind turbine (VAWT). Taking NACA0012 as the reference blade, the unsteady aerodynamic characteristics of the blade deformation at different deformation frequencies and amplitudes were investigated at low Reynolds number of 2.5 × 105. It is found that the maximum lift force of the blade with deformation amplitude of 0.06 c is raised by nearly 60% compared with that of the rigid blade. Secondly, by applying the same deceleration frequency, same pitch amplitude and different initial angles of attack to the blade, it is observed that the flow hysteresis phenomena are obviously different from that of applying various synchronous pitch and deformation amplitudes, and the special aerodynamic characteristic curves are obtained. The lift force increases significantly with the rise of deformation amplitude and drag force, while the lift-drag ratio increases in one cycle. The study in this paper proves the applicability of the blade with this deformation law in the VAWT, and provides a reference for its application on the design of VAWT. • Simultaneous deformation and pitch experiments of blade were carried out. • Unsteady aerodynamic characteristics of blade deformation were investigated. • The maximum lift of the blade was increased by nearly 60%. • This paper proves the applicability of blade with certain deformation law in VAWT. [ABSTRACT FROM AUTHOR]

A number of papers document that rules governing social dilemmas work better when implemented democratically than when imposed from above (the "effect of democracy"). This paper presents a theoretical model of the effect of democracy and uses laboratory experiments to test a key prediction emerging from the model, namely that the effect of democracy is stronger in small than in large communities. Results from a prisoner's dilemma experiment show that an effect of democracy is present in groups of all sizes but decreases strongly and becomes less persistent as the number of group members increases. In some respects, therefore, democracy appears to work best in small groups. [ABSTRACT FROM AUTHOR]

• The theories and defects of wax deposition mechanisms are comparatively analyzed. • The technology and main conclusions for inhibiting wax deposition are outlined. • Problems and future directions in wax deposition research are pointed out. This paper reviews research on wax deposition in recent years in an attempt to develop an in-depth understanding of the wax deposition phenomenon during pipeline transportation of waxy crude oil. It provides a comparative analysis of the current theories and shortcomings of the wax deposition mechanism and describes the effects of different influencing factors on wax deposition. The predictive models for wax deposition are summarized in both thermodynamic and kinetic models, and the current technical means and main conclusions for inhibiting wax deposition are outlined in detail. In addition, the paper also sums up the experimental methods commonly used in studying wax deposition. Future research directions are proposed: an in-depth study of the role of non-Newtonian features and Phase transition (heat transfer) in wax deposition and the microscopic mechanisms of wax deposition phenomena such as gelation and nucleation are needed. Moreover, the intrinsic mechanisms and action law of influencing factors such as asphalt, resin, electric field, magnetic field, and velocity should also be studied, and research about chemical inhibitors is supposed to be based on the green economy. Multiphase flow prediction models using intelligent algorithms should be established, and more accurate experimental methods and devices that meet actual pipeline flow conditions. [ABSTRACT FROM AUTHOR]

Interest in space robotic free-flyers for orbital tasks such as fabrication, observation, and on-obit servicing has led to research with Astrobee, a cuboid free-flying spacecraft-manipulator system on-board the International Space Station (ISS). Astrobee is equipped with a three degree-of-freedom robotic arm composed of a two-revolute-joint, two-link perching arm, with a three-finger gripper end effector. Astrobatics is a campaign of experiments designed to explore the use of Astrobee's robotic arm for orbital self-toss hopping maneuvers. This paper provides an overview of the Astrobee vehicle, followed by a description of the Astrobatics experiments in ground test facilities and on the ISS. Equations of motion for robotic self-toss maneuvers are developed. The results from the first Astrobatics experimental session are then compared against simulation, and the results from the second Astrobatics experimental session are provided, with a discussion of experimental observations and limitations, and followed by a description of future Astrobatics research. • Orbital hopping maneuvers aboard the International Space Station with Astrobee. • Proximal and distal self-toss maneuvers with a three degree of freedom robotic arm. • Comparison of flight data sets to a simulation self-toss model. • Self-toss hopping maneuvers as a method of initial locomotion in space operations. [ABSTRACT FROM AUTHOR]

Social comparisons are known to increase individual work morale, but because they could foster competition, they may also negatively impact how well co-workers work together. This paper uses a novel experiment to explore this potential tradeoff. The experiment varies whether members of a reference group receive relative performance information on a knowledge task and measures how this affects the willingness to subsequently help the productivity of others by sharing knowledge with them. The findings reveal that relative performance information spurs competition between members of a reference group when compared to the baseline with no such information. Yet, there is no evidence that relative performance information substantially lowers group morale, that is, the willingness to help the productivity of others in the group. These findings advance our understanding of how relative performance concerns among co-workers affect the way they work together. [ABSTRACT FROM AUTHOR]

• First experimental demonstration of a variable-stage open absorption heat pump utilizing KCOOH/H 2 O. • Effective optimization of the system performance by the solution distribution regulation. • Achieving wider operation conditions by adding new degrees of freedom into the system and by avoiding crystallization. • Performance maps in the form of psychrometric chart were obtained for VS-OAHP. Open absorption technology is a potential alternative for the heat recovery of flue gas, which is one of the main carriers for the low-grade waste heat. A variable-stage open absorption heat pump was proposed to work on wide working condition ranges by adjusting its equivalent stage through a low-pressure generator-absorber assembly. We have demonstrated that with LiBr/H 2 O as absorbent, the system could achieve COP of 1.2–2, corresponding to an equivalent stage of 1–4.6. In this paper, an experimental prototype was established, including a solution distribution regulation, which aimed to optimize the solution distribution ratio between the spraying solution in the absorber and circulation solution in the cycle and further to enhance the system performance. KCOOH/H 2 O was selected as the absorbent to overcome the challenges of crystallization and corrosion. Experimental results showed a COP of 1.17–1.85 and heat recovery rate of 48.7–89% with heat source temperature varied from 86 to110 °C and hot water delivery temperature varied from 55 to 70 °C. A simulation model based on the thermophysical properties of KCOOH/H 2 O had also been established to supplement experimental results with a wider range of external sources. Results showed that compared to LiBr/H 2 O system, KCOOH/H 2 O system had a larger working temperature range and higher heat recovery rate at the expense of a lower COP, i.e., 6–11% and 12–15% lower than that of LiBr/H 2 O system under SDR of 0.2 and 0.5 respectively. A wider concentration working range of KCOOH/H 2 O (56.4%-79.8%), temperature range of 50–95 ° C , and relative humidity range of 10–100% had been simulated to obtain performance maps of VS-OAHP system in the form of psychrometric chart. This work provided guidance for the practical operation and efficiency improvement for low-grade waste heat recovery. [ABSTRACT FROM AUTHOR]

• When the decision maker (DM) chooses a group of low income, the relative income hypothesis supposes only positive utility outcome. • The paper argues that the DM experiences also a countervailing negative utility, called the "aspirational income effect". • The countervailing effect is the result of aspiration, the desire to be associated with a high income group. • The paper runs an experiment that confirms the aspirational income effect, which cannot be explained by expected income. • The experiment shows that the aspirational income effect is much stronger than the much-touted relative income effect. According to the "relative income hypothesis," decision makers derive positive utility from identifying with a group that performs more poorly than they do. We hypothesize that decision makers simultaneously derive negative utility from identifying with such a group. The reason is that decision makers aspire toward status, and thus prefer to identify with a group that is more successful than they are. We call such proposed reason the "aspirational income hypothesis." If the aspirational income effect dominates the relative income effect, decision makers would prefer to join groups with higher rank than their own. We report data from an experiment that supports the aspirational income hypothesis. It shows that the hypothesis holds (at a weaker intensity) even when it is costly to join a higher ranking group. [ABSTRACT FROM AUTHOR]

Transport scenario building is often used to examine alternative future narratives when there is considerable uncertainty or when business-as-usual is no longer appropriate. However, the potential of scenario-building narratives to achieve a more-effective integration of land use and transport in policymaking remains understudied. This paper analyses groups of factors that influence the effectiveness of scenario-building narratives to trigger interaction processes between planning actors and thus facilitate land use and transport integration. The research uses an experimental approach based on three parallel academically constructed cases -co-creation environments with planning actors tightly controlled by researchers to explore causality. The Henares Corridor in the Madrid Metropolitan Area, Spain serves as case study. The results indicate that higher degrees of land use and transport integration are achieved when the use of scenario-building narratives facilitates complex interactions among planning actors, who employ factors from various deliberation layers (internal, individual, and global). However, the degree of land use and transport integration decreases when scenario-building narratives are paired with simpler interactions, where factors from one or two deliberation layers dominate. The paper closes by examining the implications of the obtained findings for policymaking, including a reflection on the research design validity, its limitations, and potential for application in real-life experiments. • It explores the effectiveness of 2050 narratives to facilitate land use and transport integration. • Three academically constructed cases are used, involving several planning actors. • A multi-layer framework is used to identify factors affecting to the narratives' effectiveness. [ABSTRACT FROM AUTHOR]

This paper proposed a feasible method for estimating the turbulent burning velocity of gasoline/hydrogen blends in a spark-ignited (SI) engine based on the cumulative heat release fraction, engine speed and engine geometry. The experiment was conducted on a naturally-aspirated port-injection gasoline engine equipped with a hydrogen injection system. The engine was run at 1400 rpm with different loads and hydrogen volume fractions in the intake gas. The test results showed that the addition of hydrogen benefited increasing the burning velocity and advancing the relevant crank angle for the peak burning velocity, due to the high burning and diffusion velocities of hydrogen. At 1400 rpm, a manifolds absolute pressure of 61.5 kPa and stoichiometric conditions, the peak burning velocity was raised from 11.6 to 12.3 and 14.6 m/s, and the relevant crank angle for the peak burning velocity was advanced from 21.0 to 14.0 and 8.6 oCA when the hydrogen volume fraction in the intake increased from 0% to 3% and 6%, respectively. Moreover, the effect of hydrogen addition on enhancing the burning velocity of a gasoline engine was more pronounced at low loads than that at high loads. • The charge burning velocity of H2-enriched engine is studied. • A way for estimating burning volicty in non-optical engine is proposed. • The H2-enriched engine acquired higher turbulent burning velocity. • The H2 is more effective for enhancing burning velocity at low loads. [ABSTRACT FROM AUTHOR]

Non-stationary modes of gaseous fuel combustion are of paramount importance for their efficient and safe usage in the space industry. The paper analyzes experimental and numerical data on the early stages of flame propagation in channels of different widths. It is demonstrated that there is a self-similar behavior of flame development at least at the considered stages. Qualitatively flame acceleration proceeds exponentially in channels of different widths, though the particular acceleration increment is inversely proportional to the width of the channel. Exponential acceleration is related to the positive feedback between the flame and flow dynamics, while the previous stage is associated mainly with the flame propagation induced by the expansion of combustion products. Based on the analysis of experimental data, one can estimate both the time instant at which the exponential stage starts and the increment of exponential acceleration, which in turn depends unambiguously on the normal burning rate. As a result, a novel technique for normal burning rate determination with the use of a channel reactor can be proposed. • Flame evolution in a channel goes from spherically expanding to finger flame modes. • Channel width defines exponential increment of finger flame velocity increase. • Flame acceleration process proceeds similarly in channels of different widths. • Transition point between flame modes can be used to estimate laminar burning velocity. [ABSTRACT FROM AUTHOR]

• Punishment intensity per third party decreases only mildly as the number of third party punishers increases in a group where a prisoner's dilemma interaction takes place. • Having a sufficiently large number of third parties is helpful in preventing players from selecting defection because of third party punishment. • Having too many third party players is harmful because aggregate punishment becomes too strong and even cooperators might be punished severely. • Third parties' punishment intensity is positively correlated with their beliefs on peers' punishment behaviors. • Third parties prohibit punishment of cooperators and limit over-punishment targeted at norm violators when they are given a chance to democratically decide on the levels of punishment through voting. One of the important topics in public choice is how people's free-riding behavior could differ by group size in collective action dilemmas. This paper experimentally studies how the strength of third party punishment in a prisoner's dilemma could differ by the number of third parties in a group. Our data indicate that as the number of third party punishers increases in a group, the average punishment intensity per third party punisher decreases. However, the decrease rate is very mild and therefore the size of total punishment in a group substantially increases with an increase in group size. As a result, third party punishment becomes a sufficient deterrent against a player selecting defection in the prisoner's dilemma when the number of third party punishers is sufficiently large. Nevertheless, when there are too many third party punishers in a group, a defector's expected payoff is far lower than that of a cooperator due to strong aggregate punishment, while some cooperators are even hurt through punishment. Therefore, the group incurs a huge efficiency loss. Such over-punishment results from third party punishers' conditional punishment behaviors: their punishment intensity is positively correlated with their beliefs on the peers' punitive actions. Some possible ways to coordinate punishment among peers even when group size is very large, thus enabling the efficiency loss to be mitigated, are also discussed in the paper. [ABSTRACT FROM AUTHOR]

• State of the art on experimental and numerical results on Mirrored Light-Pipe (MLP) • New experimental observations on MLP in high solar potential climates. • Various scenarios studied (impact of the reflection coefficient of the area to be illuminated, presence of an anticyclonic dome, type of sky or the ideal position of a sub-dome deflector). This paper focuses on the part of Tubular Daylight Guide Systems (TDGS): the Mirrored Light-Pipe (MLP). MLP is part of the multiple specular reflection conveyors. They allow daylight to be transported and distributed in dark rooms far from traditional openings while limiting heat transmission. It involves collecting, concentrating, and diffusing sunlight using a dome placed on the roof. It is then conveyed through a highly reflective tube and diffused into a building's room using a diffuser. Previous work (Malet-Damour et al., 2017, 2016) has shown that it was necessary to identify and study the climate in which the light pipe will be installed. A state-of-the-art of experimental and numerical results was conducted over the period from1990 to 2019. It revealed that the behavior of the light pipe depends strongly on the indoor (area to be illuminated) and outdoor (meteorology) environment. This paper presents the experimental observations of studies conducted from 2013 to 2015 on Mirrored Light-Pipe in Reunion Island. The climate in which the experiment was undertaken is presented with a focus on illuminance. In 2019, this study is the only one analyzing the performance of the light pipe in extreme situations of extreme sunlight conditions (maximum global illuminance of around 200 Klux). Experimental results based on various scenarios quantified the impact of the reflection coefficient of the area to be illuminated, the presence of an anticyclonic dome, the type of sky or the ideal position of a sub-dome deflector. The results are very encouraging. [ABSTRACT FROM AUTHOR]

• Discretion is affected by individual, relational and organisational factors. • In an experimental design, we study what affects discretion. • The use of interpreters is dependent on relation to the child. • Interpreter services are less likely to be used in acute situations. • The use of interpreter services is less dependent on the children's language skills. This paper focuses on child welfare workers' discretionary decision making. They can rely on routines, procedures and manuals as part of their work, but in the end, they still have to make a choice, based on the available information at the time. Discretionary decision making is a way of reasoning when facing uncertainty in professional work and when laws, rules and systematic knowledge must be applied in specific cases. A larger body of research on discretion and discretionary decision making in social work has developed, but there remains much ground to cover in terms of empirical analyses of how discretionary processes play out in real-life contexts. The two main research questions ask how the characteristics of each child and context and of social workers and their work situation affect the latter's decision to use interpreter services in their work with unaccompanied minors and children from minority backgrounds. The decision to use or not to use interpreter services in different situations, as an act of discretionary decision making by child welfare workers, is analysed in this paper. To study discretionary decision making among child welfare workers, a combination of a traditional survey and a vignette experiment has been used, bringing together organisational features, individual traits and situational characteristics. The findings indicate that interpreter services are less likely to be used in acute situations and more likely to be used with the children whom the child welfare staff members know better, irrespective of the children's language skills. The analyses also show varying effects of the staff's training and educational backgrounds, and surprisingly, the negative effects of institutional guidelines. One possible interpretation of this is that the guidelines are perceived as rigid constraints, instead of positive recommendations for actions. [ABSTRACT FROM AUTHOR]

• A bolted reinforced honeycomb was experimentally and numerically studied. • Both Poisson's ratio and in-plane mechanical properties were researched. • The study characterizes the effects of the relative thickness of the corrugated plate and reinforced plate. • Three design strategies - layered, internal and external, and space filling - were adopted to further regulate Poisson's ratio. The use of large honeycomb structures is becoming increasingly widespread, with many specialized honeycomb structures being produced through additive manufacturing and laser cutting technologies. However, the high manufacturing costs and low efficiency associated with these methods limit their applicability. In this paper, reinforced honeycombs with a total length of nearly 1 m were assembled using bolts. The effects of relative thickness and corrugated plate angle on Poisson's ratio and mechanical properties were investigated both experimentally and numerically. Additionally, three design strategies - layered, internal and external, and space filling - were adopted to further regulate Poisson's ratio. The results show that relative thickness, angle, and the aforementioned design strategies can all be used to regulate Poisson's ratio. As the thickness of the reinforced plate increases, energy absorption (EA) increases, but specific energy absorption (SEA) decreases. The reinforced honeycomb structure (RHC) exhibits the best energy absorption and SEA at a 60° angle. Through hierarchical, internal, and external designs, this paper shows that the reinforced honeycomb structure with one layer of reinforcement plus one layer of non-reinforcement (1+1-RHC) has the largest negative Poisson's ratio effect. Furthermore, the transition structure between RHC and 1+1-RHC is studied through unreinforced space filling design. The fabrication method presented here promises low-cost and large-scale fabrication with the ability to program Poisson's ratio, making it suitable for applications in protective gear and smart energy absorbing devices. [ABSTRACT FROM AUTHOR]

This paper presents the first experimental validation of the hybrid seismic analysis, previously developed by the authors, by simulating the structural behavior of a full-scale base-isolated building specimen tested at the E-Defense. The two-dimensional structural behavior of the lead rubber bearings (LRBs) is predicted by a machine learning model (MLM) previously developed by the authors, whereas analytical models describe the response of the superstructure. A Python script has been developed to incorporate both analytical models and MLMs into an explicit time integration method to perform three-dimensional hybrid seismic analyses. Moreover, conventional time history analyses have been carried out using a bilinear model for the isolation devices. Experimental, ML-based, and conventional analysis responses of 14 shake table motions are processed and compared in terms of hysteresis curves of the isolation layer, roof displacement and peak floor acceleration. Overall, hybrid seismic analysis showed better results than conventional one in terms of capturing the energy dissipation capacity of the isolation layer (maximum a20-index of 0.859 for the drift and 0.720 for the shear with respect to experiment). Similarly, roof displacement was predicted with a maximum a20-index value of 0.832. Besides, the maximum average computation time of hybrid seismic analysis was 1.78 s per integration time-step. Therefore, the efficiency of the hybrid seismic analysis is experimentally proven in this paper in terms of both accuracy and applicability. This machine learning-based analysis method is strongly recommended to simulate time-history response of complex structures. • Hybrid seismic analysis experimentally validated on a full-scale base-isolated building. • Integration of analytical models and machine learning models to simulate responses. • Accurate predictions of responses compared to conventional analysis. • Applicability and efficiency demonstrated for complex structures. [ABSTRACT FROM AUTHOR]

• An experimental rig of a novel bubble pump with diffusion gas has been built. • The refrigerant generating and pumping performance of bubble pump were tested. • The influences of 5 independent variables on bubble pump performance were studied. • The diffusion gas affected significantly on the performance of bubble pump. A closed experimental system has been built to explore the performance of refrigerant generating bubble pump (used in diffusion absorption heat transformer), in which the refrigerant generation is based on a diffusion generation process and the absorbent solution is lifted by vapor mixture of diffusion gas and refrigerant. In experiments, R134a, H 2 O and HCOOK solution were employed as diffusion gas, refrigerant and absorbent for refrigerant, respectively. The influences of concentrations (the mass fraction of HCOOK), system pressures, motive heads, generating temperatures and diffusion gas flow rates on the refrigerant generating and solution pumping performance were investigated. The refrigerant flow rate was used to evaluate the refrigerant generating performance, while the solution flow rate and pumping ratio were used to evaluate the solution pumping performance. The experimental results showed that: (1) the increase of generating temperature and diffusion gas flow rate or the decrease of concentration and system pressure led to the increase of refrigerant flow rate; (2) the solution flow rate and pumping ratio were remarkably impacted by the motive head and diffusion gas flow rate; (3) the solution flow rate and pumping ratio increased with the increase of motive head or the decrease of diffusion gas flow rate. The results obtained in the paper will helpful to the design and optimization of the refrigerant generating bubble pump in the diffusion absorption heat transformer. [ABSTRACT FROM AUTHOR]

Shale reservoirs have complex mineral types and are highly sensitive to external fluids. In this paper, a method to determine the wettability of shale reservoirs is firstly established based on the nuclear magnetic resonance method. Then, sensitivity evaluation experiments were conducted to evaluate the wettability of typical lithologic shales to acid, alkali, slick water, guar gum gel-breaking solution, CO 2 and 0.5% concentration composite system. Finally, the sensitivity characteristics of the wettability of different shale types to external fluids were revealed. Results show that: (a) the pores of shale are more hydrophilic than lipophilic, while the wettability of clay microscale pores and small pores is mainly hydrophilic and neutral. (b) After reacting with acid solution, the wettability changes from hydrophilic to neutral and hydrophilic. (c) Acid solution has a strong improvement effect on the porosity of Jiaolige argillaceous sandstone. Alkaline solution and CO 2 have weak improvement effect on porosity. Two dimensional nuclear magnetic resonance of core 13–33 (SH) -2 saturated with water and immersed in external fluids. [Display omitted] • Sensitivity evaluation experiments of external fluids on matrix permeability is conducted. • The mechanism of external fluid influence on matrix permeability is quantitatively analyzed. • Sensitivity evaluation experiments were conducted on the matrix/bedding permeability. [ABSTRACT FROM AUTHOR]

Tip cavitation remains a complex and critical concern for waterjet pumps, affecting the safety and efficiency of pump operation. This paper aims to explore the cavitation scale's evolution law, the cavitation structure's evolution characteristics and mechanisms, and how these factors affect pump performance. A synchronous experimental system consisting of a test pump, a high-speed camera, and pressure transducers has been established. Results show that the tip cavitation mainly consists of primary leakage vortex cavitation (PLTVC), secondary leakage vortex cavitation (STLVC), and suction surface attached cavitation near the blade tip (SSAC). The gray level-based image processing method is used to reveal the law of cavitation scale growth rate and vapor fraction distribution. The tip cavitation scale's growth rate increased as the cavitation number decreased. The rapid expansion of the attached cavitation promotes the formation of a re-entrant jet, cavity shedding, and the formation of perpendicular cavitating vortices (PCVs). It was then found that for every 0.1 decrease in cavitation number, the PCV scale in the blade overlap region increased by about 14.1 % during σ =0.256–0.206, which severely blocked the tip passage flow and accelerated the degradation of pump performance. The spatial-temporal evolution of the PCVs is classified into three stages: the shedding stage of the attached cavity, the stage that the shedding cavities change the migrating direction and form the PCVs, and the collage stage of the PCVs. With cavitation numbers of 0.256 and 0.223, the PCV evolves at roughly 194 Hz and 144 Hz, which results in pressure fluctuations of approximate frequency. [ABSTRACT FROM AUTHOR]

Solar air Brayton cycle is a promising option to adjust the renewable power fluctuation due to its quick load regulation capacity. For the successful design and deployment of the solar air Brayton cycle system, the dynamic operation performance of solar collectors under real operating conditions are of great importance. In this study, experiments of a solar collector consisting of the heliostat field and the air receiver are carried out. Based on the experimental investigation of the operating characteristics for the solar collector, a dynamic model is further developed and well-validated to couple the heliostat field and air receiver. The dynamic performance of the air receiver is studied with various factors, including the DNI change and the receiver heat capacity. The results show that the receiver outlet temperature can reach up to 882 °C with a pressure loss of 7.10 kPa and a thermal power of 132 kW during the experiment. Two operation strategies of the air receiver are compared by carrying out the intraday simulation and the constant-outlet-temperature control strategy is more suitable for fast start-up. The method developed in this paper can serve as an efficient tool for the understanding, design and optimization of solar collectors. • Pressured air is heated over 880 °C by a solar receiver. • The operation performance of solar air receiver is explored. • Dynamic model coupling heliostat field and receiver is developed. • The dynamic model is validated by the experimental data. • Two operation strategies of the solar air receiver are compared. [ABSTRACT FROM AUTHOR]

• A new multiple tube bubble pump setup with pressure difference has been studied. • The vapor generating and liquid pumping performance of bubble pump were tested. • The influences of 4 independent variables on bubble pump performance were studied. • The multiple tube bubble pump had little limitation to vapor and liquid flow rate. A closed multiple lifting tube bubble pump setup with pressure difference has been built to explore the vapor generating and liquid pumping performance of diffusion gas generating bubble pump, which is used in diffusion absorption heat transformer. In all the experiments, R134a and TEGDME were employed as diffusion gas and absorbent. The influences of concentration (the mass fraction of R134a in the solution), motive head, lifting tube number and heat input on the performance of bubble pump were investigated. The R134a mass flow rate was used to evaluate vapor generating performance, while the dilute solution mass flow rate and pumping ratio were used to evaluate liquid pumping performance. The experimental results showed that: (1) the increase of concentration was beneficial to generation of R134a which resulted in larger R134a flow rate and lower generating temperature, and it also led to larger dilute solution flow rate; (2) larger motive head led to larger R134a flow rate and smaller pumping ratio, but resulted in higher pressure and generating temperature; (3) the variations of R134a flow rate, dilute solution flow rate and pumping ratio were not varied when lifting tube number changed, but the upper limit of R134a and dilute solution flow rate increased significant with the increase of lifting tube number. It was concluded that the bubble pump with multiple lifting tube had little limitation to the fluid flow rate. The results obtained in the paper will be helpful to the further study of diffusion gas generating bubble pump. [ABSTRACT FROM AUTHOR]

In social and economic interactions, individuals often exploit informational asymmetries and behave dishonestly to pursue private ends. In many of these situations, the costs and benefits from dishonest behavior do not accrue immediately and at the same time. In this paper, we experimentally investigate the role of time on dishonesty. Contrary to our predictions, we find that neither delaying the gains from cheating nor increasing temporal engagement with one's own unethical behavior reduces the likelihood of cheating. Furthermore, providing individuals with an excuse to lie by inserting a delay between the time when private information is obtained and when it is reported does not affect cheating. [ABSTRACT FROM AUTHOR]

Bistable structures, a class of highly geometrically nonlinear morphing structures, have two stable configurations that remain in their respective equilibrium positions without the continuous application of an external force. This paper aims to summarise, review, and assess the literature about the theoretical studies, driving methods, numerical simulations, experimental investigations, and fields of application of the structures. The theoretical models are separated into anisotropic and isotropic composites based on the properties of the material. The generalised methods to study the bistability of structures with various properties are presented. The driving methods used to trigger the snap of one equilibrium structure to the other include mechanical force, piezoelectric actuation, shape memory alloy actuation, thermal actuation, and magnetic actuation. Numerical simulations of the curing process during manufacture and of the morphing process, which includes the snap-through and snap-back of the bistable structure, are reviewed. Moreover, the experimental investigations of structures with unsymmetric and antisymmetric layups are also presented. Bistable composite laminates and their structures have been used in aerospace, bionics, energy harvesting, and other fields due to their unusual behaviour and morphing potential. This paper also highlights the remaining challenges and possible future work on bistable composite transition, from phenomenon to potential applications. • Summarise, review, and assess the literatures of the bistable morphing composite structures. • References are divided into theoretical studies, driving methods, numerical simulations, experiments and application fields. • The remaining challenges and possible future work on bistable composite transition. [ABSTRACT FROM AUTHOR]

In this paper, a new type of blade model driven by single input for vertical axis wind turbine was developed, and it could achieve synchronous active deformation for both of blade leading edge and trailing edge. Firstly, by taking the concept of ribs and by taking NACA0012 airfoil as an example, the mechanical structure and skin with adhesion mechanism of pre-tightening force was adopted based on the continuous deflection and deformation mode of the blade leading and trailing edges with constant thickness. In this way, the adaptive blade could achieve reciprocating smooth deformation with different cambers. Secondly, the experimental platform for measurement of wind tunnel force and flow visualization was built up, where the smoke wire instrument, seven-hole probe, two-component balance were applied for measuring of quasi steady force and flow visualization under different deformation quantities. Finally, the aerodynamic performance of adaptive blade under different deformation factors was revealed. It is found that within an appropriate range of deformation factor, the blade aerodynamic performance can be improved by deforming. When exceeding the critical camber, the friction resistance becomes a dominant factor effecting blade aerodynamic performance. In all, the experimental results in this paper could provide reference for subsequent unsteady experiments. • A novel type of blade model driven by single input for VAWT is developed. • A new adhesion scheme for blade surface skins is proposed. • Aerodynamic performance can be improved by deformation blade. • Test results could provide reference for future subsequent unsteady experiments. [ABSTRACT FROM AUTHOR]

Abstract Winter road maintenance is costly but it is necessary in order to keep roads accessible and safe during winter. Current winter road maintenance methods use 600,000 tons of salt annually, in the Nordic countries. The salt ends up in the environment along the roads and results in environmental challenges. Alternative winter maintenance methods that use heat instead of salt are in use today. However, those systems are designed to use high temperature of about 20–35 °C. This paper presents a numerical model for designing low temperature (4–8 °C) hydronic heated pavements (HHP). The model is validated against an experimental setup and different control strategies are evaluated. The validation indicated that the developed model can predict the behavior of the HHP with a root mean square error (RMSE) <1.4 °C for surface temperatures and <0.4 °C for the return fluid. In this paper the model is used with two different control strategies. A basic strategy controlling the system based on air temperature and one strategy based on dew point temperature. With dew point regulation the energy consumption can be reduced by 62%. However, the energy consumption is still in the range of 125–180kWh/m2 for the location of Östersund, Sweden. We found that the HHP system can utilize low temperature sources like waste energy or geothermal energy that is freely available. By using renewable energy for winter road maintenance, the environmental impact from winter road maintenance can be reduced. Highligths • Dewpoint control reduces the energy demand for heated pavements. • Low supply temperatures of 2-8 °C makes it possible to use renewable energy sources. • Presents a 3-D numerical model including the fluid domain for heated pavements. • Snow ploughing strategies affects the energy usage more a low temperature. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a conceptual design of Passive Containment Cooling System with Closed-Loop Heat Pipe Technology (PCSHP) is studied using both experimental and computational methods. By studying on the thermal-hydraulic parameters in system running, such as temperature, pressure and flow rate, the paper mainly focuses on the start-up characteristics, the steady-state operating characteristics, the heat transfer capacity and the natural circulation capacity of the system. Hence, the principle experiment and GOTHIC simulation were carried out under start-up conditions, steady-state conditions and decay heat simulation conditions. The applicability and conservatism of the GOTHIC model is evaluated by comparing the simulating results with the experimental results. The rationality of the system design is validated by both the principle experiment and GOTHIC simulation. It is preliminarily judged that the heat pipe technology is feasible to apply to the Passive Containment Cooling System (PCCS) of nuclear power plant. [ABSTRACT FROM AUTHOR]

Highlights • Abrasive supercritical CO 2 jet is a new type of jet that can be used into reservoir fracturing. • The effects of influencing parameters on rock perforation performance using abrasive supercritical CO 2 jet were revealed in this paper. • An experimental system was set up to conduct the rock perforation experiment using the abrasive supercritical CO 2 jet. Abstract abrasive supercritical CO 2 (SC-CO 2) jet perforation is the key procedure in the SC-CO 2 fracturing, which will directly affect the exploitation of oil and gas. The properties of the SC-CO 2 fluid, such as density, viscosity, diffusivity and so on, change greatly with the variation of temperature and pressure, which directly affect the particle-carrying ability and perforation performance. This paper investigates the influence of key parameters, such as ambient pressure, fluid temperature, jet standoff distance and jet pressure, on the perforation ability of abrasive SC-CO 2 jet. The results indicate that the ambient pressure has no significant effect on perforation under the condition of a fixed jet differential pressure. When the confining pressure increases from 5 to 15 MPa, the hole depth and diameter decrease by 5.7% and 18.6% respectively. The hole depth increases slightly with the rising of jet temperature. In addition, with the jet temperature rising per 20℃ within the range from 40 to 100℃ and the standoff distances being 4 to 10 mm, the hole depths increase by 3.8% and 12.0% in average, respectively. Furthermore, the hole depths keep unchanged at first and then decrease rapidly with the increasing standoff distance. However, the hole diameters and effectively impinged areas increase with the standoff distance. The influences of SC-CO 2 jet pressure on the perforation performance are similar to that of the conventional jet. Additonally, both effective hole depths and volumes increase linearly in general with the increasing of jet pressure. The hole depths averagely increase by 36.6% when the SC-CO 2 jet pressure rising by 5 MPa. Furthermore, the research also shows that perforation performance of pre-mixed jet is better than the post-mixed jet, the volume ratio of the two kinds of perforating holes is 12.02 under these experimental conditions. All the above merits have provided a theoretical foundation and experimental proven for the field application of SC-CO 2 jet perforation technology. [ABSTRACT FROM AUTHOR]

Highlights • The paper examines the long-run effects of conflict resolution mechanisms on cooperation in contests. • Communication reduces conflict expenditure dramatically. • Third party interventions do not have an additional effect • Once communication is not possible anymore, expenditure increases occasionally. • This increase is stronger if the parties contest a single large prize rather than multiple small ones. Abstract The paper studies an experimental conflict in a repeated game and tests the robustness of communication as an intermediate conflict resolution instrument. The results show a strong and persistent impact of communication. Most conflict parties refrain from conflict expenditures even after the opportunity for communication has expired. Third party involvement with punishment options does not enhance this effect while contesting one prize rather than multiple prizes reduces it. Conflict resolution is less successful even in the long term if initial conflict intensity is rather high. [ABSTRACT FROM AUTHOR]