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The production of pulp and paper from recycled paper generates significant quantities of deinking paper sludge (DPS). This sludge contains a significant amount of organic matter (36%) as well as heavy metals such as Pb, Zn, and Cr. In this work, the incorporation of DPS (0%, 8%, 10%, and 12%) in the manufacture of clay bricks leads to valorization of this waste by showing that two of its contents considered problematic (organic matter and heavy metals) have several positive effects. It was found that the organic parts were transformed into pores after brick firing (850°C), which improved thermal insulation while keeping mechanical resistance in conformity with usual standards. For the heavy metals, which make DPS a hazardous waste, a leaching test was employed. The results show that these metals were trapped in the ceramic matrix after the firing of bricks at a high temperature, resulting in a final product that was not dangerous. Other tests were carried out on bricks with DPS to evaluate density, water absorption, shrinkage, loss on ignition, porosity, and microstructure in order to characterize this new product. It was concluded that DPS can be used in clay bricks as an asset for the formation of pores to enhance thermal insulation. The addition of DPS can be optimized at 10% to comply with the standard and not exceed the required values for shrinkage, water absorption, and loss on ignition. [ABSTRACT FROM AUTHOR]

The filter paper (FP) method, a cost-effective, versatile, and convenient approach, has found extensive application in analyzing fine-grained soils, enabling the successful measurement of a broad spectrum of total and matric suctions. However, using the FP method in sand with a limited range of suction profiles has been notably underrepresented in the existing literature. Therefore, this study investigated the applicability of the contact FP method in establishing soil water retention curves (SWRCs) using five distinct FP calibration curves for 10 poorly graded sands. Among these calibration curves, the one presented by Chandler yielded the highest suction values, which were followed by those of ASTM. Furthermore, the FP results were subjected to fitting with a mathmatical model, which led to the observation that the overall trends in the obtained SWRCs displayed smooth sigmoidal shapes, resulting in a complete and coherent SWRCs. The SWRC results of five sand samples were assessed through validation against the hanging column technique (HCT) results, indicating a high degree of concordance and affirming the suitability of the FP method for sands characterized by a limited suction profile. Notably, the entire range of suction values fell within the 0.01–20 kPa range based on the calibration curves presented by Chandler and ASTM for all the examined sand samples, except sands 9 and 10. Furthermore, the suction values were unobtainable using the two aforementioned calibration curves within the ranges of 0.01–1.47 kPa and 0.01–0.172 kPa. [ABSTRACT FROM AUTHOR]

Cement stabilization is a widely applied technique in improving the workability and geotechnical properties of soft clay. This paper investigated the influence of cement stabilization on the soil–water characteristic curve (SWCC) and the deformation behavior of unsaturated cement–stabilized soft clay. The combined effect of cementation and partial saturation on the hydromechanical behavior of cement-stabilized soils was discussed. The SWCC of stabilized soil was measured in the full suction range under drying and wetting paths using the pressure plate method, the filter paper method, and the vapor equilibrium technique. The deformation behaviors of cement-stabilized soft soil were investigated by conducting suction-controlled oedometer tests. Furthermore, scanning electron microscope micrographs and mercury intrusion porosimetry tests were performed to investigate the effects of cement content on the evolution of soil pore structures. The test results showed that the water retention capacity of the stabilized soft clay increased with increasing cement content. The SWCC showed a significant hysteretic behavior in the boundary effect zone and transition zone, whereas the hysteretic effect was unapparent in the residual zone. The increased cement content had a more significant hysteretic effect on the SWCC. The deformation resistance capacity increased as the cement content and matric suction increased. However, the effect of matric suction on deformation resistance capacity decreased as the cement content increased. With the increase in cement content, the macropores were converted to small interaggregate pores, the pore spaces were distributed more uniformly, and the particle surface became rougher, resulting in higher water retention capacity and significant hysteresis of the SWCC. [ABSTRACT FROM AUTHOR]

The article discusses the importance of reproducibility in academic research, particularly in the field of structural engineering. It acknowledges the challenges in achieving reproducibility, such as data storage and computing requirements, as well as proprietary issues. The authors argue for the development of a reproducibility policy in the Journal of Structural Engineering and the Journal of Bridge Engineering, taking into account the nature and culture of research in these subdisciplines. They propose a classification system that emphasizes the availability of data and metadata, and encourage authors to go beyond data availability by making models and other materials accessible. To incentivize research and data availability, the journals will provide a visible recognition badge for papers with open data/models/codes and may consider special recognition for these papers. The authors also outline the review process for data-verified papers, which involves three associate editors verifying the availability and representativeness of the data. [Extracted from the article]

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. [ABSTRACT FROM AUTHOR]

Biological and abiotic sorptions as well as kinetic experiments were performed to elucidate the mechanism by which color was being removed from paper mill effluents using anaerobic composting. Experiments were performed using pulp mill upset tank wastewater (color=5,500 PCU) and E stage filtrate (color=10,300 PCU). Color removal experiments using active and gamma sterilized compost showed that the color removal capacity for both wastewaters was nine times higher when using active compost than for those reactors using gamma sterilized compost. Final decolorization for pulp mill upset tank and E stage filtrate was 91 and 83%, respectively, while only 33% decolorization was achieved with gamma sterilized compost. Kinetic tests also showed higher color degradation rates when using active compost compared to sterilized compost. Additional experiments demonstrated that biological color removal appears to be robust with respect to pH and is largely unaffected by pH over a range from pH 5 to 10, typical values for the effluents in paper mills. The effect of aging in sorption were tested and results showed that virgin compost could establish a microbial population in less than 50 days which resulted in a compost with sorption capacity similar to the aged compost. DOI: 10.1061/(ASCE)EE.1943-7870.0000204 CE Database subject headings: Color; Anaerobic treatment; Biological processes; Paper mills; Effluents; Wastewater management. Author keywords: Decolorization; Anaerobic compost; Paper mill effluent.

This article discusses the importance of reproducibility in academic research, specifically in the field of bridge engineering. The authors argue that reproducibility is challenging due to factors such as paper documentation, technology constraints, and proprietary issues. They propose implementing a policy that encourages researchers to make their data and models available to others, although they acknowledge that full reproducibility may not always be practical. To incentivize this practice, the Journal of Bridge Engineering plans to introduce a visible recognition badge for papers that provide open data, models, and codes. The authors also outline the review process for papers seeking the "Data Verified Paper" designation. [Extracted from the article]

The aim of this paper is to propose a step by step method to establish and validate a relevant, dynamical model of the activated sludge process for the paper mill industry. The model is established by considering the specificities of the effluent to be treated. It uses the biochemical oxygen demand (BOD) measurement, which allows a direct correlation between the state variables of the model and the measurements. This model is validated on a pilot plant of semi-industrial size fed with industrial paper mill effluents. The parameter estimation is based on an analysis of the sensitivities. The results are compared with a model based on chemical oxygen demand (COD) partitioning which is issued from the simplification of the activated sludge model number 1 (ASM1) model. Finally, the model dealing with BOD measurements not only shows the best performances, but is also the easiest to implement, overcoming one main obstacle to efficient monitoring and control in paper mill wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Distributed solar generation (DSG) has been growing over the previous years because of its numerous advantages of being sustainable, flexible, reliable, and increasingly affordable. DSG is a broad and multidisciplinary research field because it relates to various fields in engineering, social sciences, economics, public policy, and others. Developing a holistic understanding of the state of research related to DSG can be difficult. Motivated to provide that understanding, the goal of this paper is to explore current and emerging multidisciplinary research trends associated with DSG. To achieve that, (1) a large data set of approximately 66,000 publications was collected; (2) the papers were labeled using keywords for topics including "Batteries and Storage," "Solar," "Complex Modeling," "Machine Learning (ML) and Artificial Intelligence (AI)," "Resilience, Vulnerability, and Disasters," "Policies and Incentives," "Social Aspects," "Economics," "Smart Grid," "Finance," "Social Equity," "Microgrid," and "Virtual Power Plant"; and (3) the data set was analyzed using scientometric and social network analysis (SNA) in respect to publication counts, citation counts, and interconnectivity between the topics. Notable findings were analyzed to describe current and emerging trends. It was found that social equity has high citation counts contrasted by few publications, indicating a possible strong need for research. There is also rapidly growing research in ML and AI in the context of DSG during recent years. Other research topics, such as smart grids, have been attracting fewer publications. The results also highlight the need for multidisciplinary research connecting the topics. To conclude, future research is suggested to explore research needs in the areas of social aspects, social justice and equity, public policy and incentives, and ML/AI. The findings should benefit researchers and stakeholders with a holistic understanding of multidisciplinary DSG-related research and provide insight for planning new research and funding opportunities. [ABSTRACT FROM AUTHOR]

The problem of corrosion in oil and gas pipelines is one of the major factors affecting the process safety and efficient sustainability development of the oil and gas industry. To gain a better understanding of global research trends and dynamics in the field of oil and gas pipeline corrosion and to advance the development of corrosion control technology, we conducted a literature review using a sample of 1,745 papers from the Web of Science (WOS) database published from 2002 to 2022. We employed a bibliometric analysis approach employed to investigate the distribution of publications over time, geographic regions, major organizations, major authors, journal cocitation, and literature cocitation, and to identify research hotspots and frontiers. The results revealed an exponential growth in the overall number of papers, with the most rapid increase occurring in the last 4 years. China, the US, Canada, the United Kingdom, and Brazil emerged as the most active countries in oil and natural gas pipeline corrosion research, and Mexico, Canada, and Australia also exhibited significant influence in the field. The journals Engineering Failure Analysis, Corrosion, and Corrosion Science had the highest number of publications and impact in this domain. Notably, Corrosion Science stood out as the most influential and highly regarded journal in the corrosion field. The fundamental theories and research framework in the realm of oil and natural gas pipeline corrosion have been primarily established, and a large number of research directions and frontier branches are emerging. The impact of flow parameters on corrosion, pipeline reliability assessment, and analysis of corrosion defects and failures are identified as the three main development paths in this field. In terms of research methodologies, machine learning techniques are becoming increasingly prevalent, with a growing number of studies adopting various machine learning methods. Among these methods, explainable deep learning is at the forefront of development in the field of oil and natural gas pipeline corrosion. [ABSTRACT FROM AUTHOR]

Sidewalks represent a fundamental part of the infrastructure in cities, allowing equal and barrier-free access for everyone. However, while pedestrian accessibility is a frequent concern in developed countries, it receives little attention in developing regions. Regarding studies on pedestrian infrastructure, the characteristics of the sidewalk that are considered are also varied, as well as the aspects mainly focused on by such research. Moreover, the perception of the target user group, especially of people with disabilities, can be an important topic in this area. In this context, this paper presents a systematic literature review of sidewalk assessments, focusing on accessibility, to answer the following research questions. In which contexts are sidewalk assessments carried out? Which aspects and elements are usually considered? Are people with disabilities included? We noticed that sidewalk assessments have been a recent study topic, but with less focus on the Global South. Besides accessibility, walkability stands out as a research focus, and the sidewalk elements most addressed are surface conditions and width. Finally, the perceptions of people, especially with disabilities, are scarcely considered, demonstrating an important research gap. The sidewalk is a very important element of the city. It should allow walking, with accessibility for everyone. However, there are three things to consider: (i) sometimes the importance of an accessible sidewalk is not recognized in developing countries; (ii) the different characteristics and aspects of the sidewalk are considered differently between different studies; and (iii) the opinions of pedestrians, especially of people with disabilities, are not always present in evaluations of sidewalks. Thus, the aim of this study is to develop a systematic literature review to better understand how the sidewalks are evaluated in different studies, especially considering accessibility. In the study, the previous three findings were confirmed, with the conclusion that (i) evaluation of sidewalks is a recent topic of study, but mostly in developed countries; (ii) accessibility, walkability, and safety are frequent topics in sidewalk assessments, with surface conditions and width being the most evaluated characteristics; and (iii) few studies consider the opinions of pedestrians with disabilities. These three findings indicate topics that need to be better studied and focused on in urban planning. [ABSTRACT FROM AUTHOR]

The Journal of Construction Engineering & Management has announced the recipients of the 2023 Best Paper Award. The winning paper, titled "Deep Learning Image Captioning in Construction Management: A Feasibility Study," explores the automation of deep learning for image captioning in the construction management field. The authors present a systematic approach that includes developing a linguistic schema, creating a dataset of manually captioned images, and evaluating six deep-learning methods using eight metrics. The paper concludes that a method combining two advanced deep learning processes performed the best, and that automatic captioning in construction management is feasible. The article provides valuable insights and suggestions for future development in this area. [Extracted from the article]

This study deals with the recovery of deinking sludge (DS) generated during waste paper recycling. The aim is to integrate this sludge in the fired-bricks formulation with different percentages. These mixtures are fired, and the study of the general aspect, loss on fire, and water absorption enables characterization of this material. Different compression tests are carried out on studied samples to characterize the strength and compare its performance to the standard. The mixtures' optimization and the elaboration conditions are the main objectives to obtain a new construction material with competitive performances conforming to the standards. [ABSTRACT FROM AUTHOR]

In this study, the energy, economic, and environmental (3E) analysis on two waste-to-energy (WtE) technologies, for example, anaerobic digestion (AD) and incineration, for the treatment of municipal solid waste in Surat (Gujarat, India) was conducted. For energy criteria, the potential for energy recovery from municipal solid wastes (MSW) through AD and incineration was considered. The economic analysis that was carried out considered preprocessing, transportation, land, capital investment, and operational and maintenance costs that were incurred. The revenue that was generated by selling the electricity and compost was considered along with the recycling value of the paper waste. For environmental analysis, the global warming and acidification potentials (APs) were considered from the emissions that were produced during the treatment, transport, and disposal along with the displaced emissions. The results indicated that the average daily solid waste generation from Surat was 0.33 kg/person and the average total solid waste generation was 2080 t/day. Organic waste was the largest fraction (35.6%) followed by inert waste (13.5%), construction and demolition waste (12.4%), and recyclable waste, such as glass, rubber, and metal (11.2%). AD had less energy generation potential (9.89 MW) compared with incineration (16.99 MW). From an economic perspective, incineration had a higher profit (INR 1.48 million/day) than AD (INR 1.38 million/day). The environmental analysis showed that incineration had greater potential to reduce global warming and acidification compared with AD. The 3E analysis revealed that incineration was the superior technology choice. [ABSTRACT FROM AUTHOR]

The paper recycling process generates a sludge characterized by a high content of cellulose fiber. To understand the behavior of this fibrous material, this article presents an interpretation of the geotechnical behavior of a waste sludge from a paper recycling plant situated in southern Brazil using data from laboratory tests. Engineering properties of compacted paper mill sludges are similar to those of most fibrous organic soils: low hydraulic conductivity upon compression and high compressibility. The waste studied has a water content of approximately 250%, organic content of 48%, mineral charges, and water. The one-dimensional compressibility parameters are indicative of high compressibility. For the determination of the strength parameters of the material, undrained triaxial tests were carried out. An incredibly high effective friction angle ([lowercase_phi_synonym]′=53°) was found, probably because of the fibrous nature of the paper sludge. In addition, hydraulic conductivity tests were performed on a flexible wall permeameter. The hydraulic conductivity of the fibrous paper sludge reached values near10-9 m/s. The results showed that the paper mill sludge is a ductile material with reduced hydraulic conductivity and elevated shear strength that could have multiple applications, such as in the construction of bottom liners, cover liners, and steep side-slope liners for solid-waste landfills. [ABSTRACT FROM AUTHOR]

The Journal of Management in Engineering (JME) is celebrating its 40th anniversary as a premier academic journal in the project engineering and construction management field. The journal initially focused on the importance of managerial issues in the engineering and construction industry and has since evolved to cover a wide range of topics. The journal has achieved a commendable impact factor and continues to attract diverse papers from academia and industry. JME has added new associate editors and editorial board members to enhance its expertise and has introduced special collections on important and emerging topics. The journal also utilizes social media platforms to engage with a wider audience. The editor in chief expresses gratitude to all contributors and welcomes feedback and suggestions for future research. [Extracted from the article]

Paper mill sludge is often incinerated for heat recovery and volume reduction. In Italy, about 600,000 t of paper mill sludge is produced yearly. About 6 kg of sludge is produced per ton of paper produced. The paper mill sludge is recovered from a primary mechanical separation process. When it is combusted as a single fuel source, it produces paper mill sludge ash (PA). In this project, PA was studied to evaluate its use as a supplementary cementitious material in mortars and concrete manufacturing. On the basis of the data collected, it was concluded that PA, if used to replace up to 10% of the portland cement, shows a positive effect on the mechanical performance of mortars. On the other hand, because of its high fineness and consequently high water absorption, it required a higher amount of water. It was concluded that the use of PA should not be higher than 10% by weight of the cement replaced, unless mortar mixtures are judiciously proportioned. [ABSTRACT FROM AUTHOR]

Biological hydrogen production from the anaerobic fermentation of ultrasonic-pretreated paper mill sludge started at a pH of 5.5 and a temperature of 36.5°C. When the sludge reaction time (SRT) was 32 h, the organic loading rate (OLR) was 3,000 mg chennai oxygen demand (COD)·L-1·d-1, and the hydrogen production yield was 620.8 mL H2/g COD. The Gompertz equation was used for regression analysis of accumulated hydrogen yield, which indicated that R2 was 0.99. Hydrogen was produced by typical ethanol-type fermentation and the utilization of organic material was 31.8%. [ABSTRACT FROM AUTHOR]

Paper clay has several properties that make its use in vertical barriers very promising. In this paper the characteristics of two paper sludges (which will also be referred to as paper clays) one from the Erving Paper Company and one from the International Paper Company are considered. To determine the feasibility of paper clay for heavy metal attenuation, batch tests, column tests, hydraulic conductivity tests, and pressure filtration tests were performed. Batch testing showed that the metal, the distribution coefficient (Kd) ranged from as low as 0.002 L/g for manganese to as high as 6.7 L/g for lead in International paper clay. In the Erving paper clay the Kd ranged from 0.007 L/g for manganese to 1.9 L/g for cadmium, while the International paper clay Kd ranged from 0.002 L/g for manganese to 6.7 L/g for lead. Chemisorption was established as the predominant metal binding mechanism in both clays with the only exceptions being manganese adsorption on International paper clay that indicated a constant partitioning, and copper and lead on Erving paper clay that indicated constant partitioning and cooperative adsorption, respectively. Both hydraulic conductivity and pressure filtration tests revealed permeabilities ranging from 10-5 to 10-7 cm/s. Chloride testing showed that the coefficient of hydrodynamic dispersion (D) within paper clay is on the order of 10-7 cm2/s. [ABSTRACT FROM AUTHOR]

Two investigative stages are presented in this study, which aim to establish basic standards for the use of calcined paper sludge (CPS) in the stabilization of soils. The soils were stabilized with CPS and with mixtures of CPS and cement (C). The total percentage of binder was between 3 and 6% by weight. The blending ratios (by weight) of the CPS:C mixtures were 50∶50 and 25∶75. The first stage took place in the laboratory, and the second stage, in the field, involved in situ stabilization of 250 m of subgrade using dry-mix methods. The bearing capacity of the stabilized soils was determined in the laboratory. In the second stage, the densities of the subgrade were measured in the field following compaction and deflections at 7 days. Furthermore, the evolution of its unconfined compressive strength (UCS) was measured over 90 days. The results reveal optimal mechanical behavior of the stabilized soil at CPS:C ratios of approximately 25∶75. [ABSTRACT FROM AUTHOR]

The emphasis of the current study was on the calcination of lime sludge, performed at different temperatures from 650°C to 750°C, which consumes less energy as compared to the industrial process of calcination. Different proportions of calcined lime sludge and raw lime sludge were used with cement to form cementitious binders. M25 grade concrete was prepared with the application of the prepared binders and tested for strength properties at 7 and 28 days of curing. The binder consisted of 10% substitution of cement with as-received lime sludge and 30% substitution with calcined lime sludge and produced a compressive strength of concrete approximately similar to the control concrete. Reactive lime and metakaolinite performed an active role after the calcination of lime sludge at 650°C, which worked as pozzolana. This effect is also confirmed with isothermal calorimetry of the prepared binder. The prepared binder was sustainable with approximately 20% less production cost and 55% less emission of greenhouse gases as compared to ordinary portland cement. [ABSTRACT FROM AUTHOR]

Reactor experiments were conducted to study aerobic sulfide oxidation in pulp and paper wastewaters under typical operating conditions. Data produced from these experiments were used to develop a set of sequential rate equations that describe the significant sulfide and oxygen processes in the reactors. Model parameters were estimated for three different pulp and paper wastewaters using a multiresponse procedure. The sulfide oxidation rate coefficients for the wastewaters ranged from 0.108 to 0.155 [min.sup.-1] at 35[degrees]C and approximately neutral pH. The reaction order with respect to oxygen could not be precisely estimated but appeared to be near the lower boundary for the fitting procedure (essentially zero order). Modeling of the oxygen depletion data provided evidence that the first sulfide oxidation reaction product consumed 0.5 mg of oxygen per mg of sulfide oxidized, suggesting polysulfides and elemental sulfur as the initial reaction products. The oxygen depletion modeling also suggested oxidation of the initial reaction product to a more stable intermediate which is postulated to be thiosulfate. DOI: 10.1061/(ASCE)EE.1943-7870.0000248 CE Database subject headings: Models; Hydrogen sulfides; Estimation; Paper mills; Waste stabilization ponds; Oxidation. Author keywords: Models; Hydrogen sulfides; Estimation; Paper mills; Waste stabilization ponds.

Investigates the geotechnical properties of seven paper mill sludges for landfill cover use. Method of sludge production; Water, organic content and specific gravity of paper mill sludges; Determination of the Atterberg limits of the sludge; Result of the compaction tests; Relationship between remolded permeability and water content.

Implications of conventional activated sludge (CAS) process modification to a low sludge production (LSP) process have been studied for treating pulp and paper wastewaters. The activated sludge process is modified to a two-stage design to establish a microbial food chain that would result in reduced sludge production. The return activated sludge in the LSP process bypasses the first (dispersed growth) stage to be received only by the second (predatory) stage. The resulting once-through operation of the dispersed growth (DG) stage makes it potentially susceptible to bacterial washout under hydraulic shock conditions. A sensitivity analysis of the DG stage operation was performed by varying its hydraulic residence time. The experimental data revealed that the optimal DG stage hydraulic residence is between 3 and 5 h, with bacterial washout likely to be initiated within 2 h. Based on laboratory results, it appears that a well-designed LSP system is likely to be able to handle day-to-day variations in hydraulic and organic loading rates. The LSP process produced 36% less sludge than the CAS process while consuming approximately 25% more oxygen. The treatment performance of the two systems was comparable except that the LSP sludge had much better settling and dewatering properties. DOI: 10.1061/(ASCE)0733-9372(2006)132:9(1019) CE Database subject headings: Activated sludge; Nutrients; Water management; Wastewater management; Paper mills.

This paper reports on a controlled experiment carried out to investigate the differences between novices and experts during the review of papers for engineering journals. A total of 17 young faculty members with PhD degrees were given instruction on the peer review process, and then had to review a short paper, for which the actual reviews were available. The quality of the reviews was assessed using criteria developed by editors of medical journals. The evidence obtained from this study helps to identify the critical areas in which reviewers fail to perform a good review, and then to develop strategies to overcome such limitations. CE Database subject headings: Engineering education; Publications; Faculty; Peer review.

The Le Chatelier-Anstett test was used to study the sulfate resistance of cement pastes containing calcined paper sludge waste (MC). MC was blended with two types of portland cement (PC): P1 with and P2 without C3A (ordinary portland cement, OPC, and sulfateresistant portland cement, SRPC, respectively). The study of thaumasite formation required the utilization of a third PC, P3. The results showed that sulfate resistance always decreased at higher ratios of PC replacement by MC. This behavior was attributable to the expansive synergic effect (ESE), originated by the coprecipitation of ettringite from two resources in a gypsum and water medium. Part of the ettringite formed rapidly from the Al2O3r- in MC, and rapidly or slowly from the C3A in P1, depending on whether its early pozzolanic activity was sufficient or not. Rapid-forming ettringite of both origins was induced by the sufficient specific, fast, and early pozzolanic activity resulting in the indirect stimulation of sulfate-mediated P1 hydration (its C3A content especially) by the metakaolin present in the MC. Where such activity was insufficient, however, slow-forming ettringite was generated, reducing the ESE. The substantial calcite content in MC also played a very significant role in ESE, the result of the stimulation of such hydration, concomitant sulfate attack, and thaumasite formation. Stimulation was both direct (due to initial particle moistening by the mixing water) and nondirect (due, at the very outset, to the positive and negative electrostatic charge acquired by their particles during grinding and/or mixing, and subsequently, to the zeta potential originated as PC hydration progressed). Lastly, calcite (natural or synthesized in portlandite carbonation) was shown to be needed for thaumasite to form, a process not confined solely to low-temperature environments. [ABSTRACT FROM AUTHOR]

Accurate identification of structural displacements is important for structural state assessment and performance evaluation. This paper proposes a real-time structural displacement detection model based on computer vision and deep learning. The model consists of three stages: identification, tracking, and displacement resolution. First, the displacement target is identified and tracked by the improved YOLO v7 algorithm and the improved DeepSORT algorithm. Then, the Euclidean distance method based on inverse perspective mapping (IPM-ED) is proposed for the analytical conversion of the displacement. Next, the accuracy and effectiveness of this displacement detection model are evaluated through four groups of bamboo axial compression tests. A comparative analysis is conducted between the IPM-ED displacement analysis method and the commonly used ED displacement analysis method. Finally, the robustness of this method is tested by using a cable breakage test of a cable dome structure as an application case. The research results demonstrate that the maximum average error of the four groups of bamboo displacement tests is only 3.10 mm, and the maximum relative error of peak displacement is only 6.54 mm. The RMSE basically stays around 3.5 mm. The maximum displacement error in the application case is only 4.91 mm, with a maximum MAPE of 4.94%. In addition, the error percentage under the IPM-ED algorithm is basically within 5%, while the error percentage of the ED algorithm is more than 10%. The method in this paper achieves efficient and intelligent identification of structural displacements in a non-contact manner. The proposed method is suitable for environments where the contact displacement sensor is easily affected by vibration, the site is complex and requires additional displacement sensor fixing equipment, the displacement sensor with super-high structure is unsafe to deploy, and the contact displacement sensor in narrow space is inconvenient to deploy, so it has broad application prospects. [ABSTRACT FROM AUTHOR]

The researchers at Arizona State University's Center for Alternative Building Studies (CABS) revealed the advantages of using environmental friendly papercrete, used in construction of buildings. Paperecrete is created from waste paper, cement and other ingredients.

Natural pozzolans are defined as either raw (volcanic material, limestone) or calcined natural materials (burnt shale, calcined kaolinite) with pozzolanic properties. Historically, they are among the oldest materials that have been used in combination with lime for construction purposes. For example, Santorin earth is a natural pozzolan from a volcanic eruption around 1500 BCE on an island of the same name in Greece. Over the last decades, research into cement matrices has been changing direction, owing to deeper environmental concerns over the impact of the cement industry and its consequences for climate change. Global environmental policies are increasingly strict, prioritizing the re-use rather than the disposal of industrial wastes. In this context, one of the biggest challenges is the search for strategies that promote the industrial rotation of high volumes of wastes in their productive cycles. The main purpose of this research is to widen the existing knowledge base on the behavior of new mineral pozzolans of high added value in the cement sector, lending special attention to paper sludge wastes generated in the process of paper manufacture, in which recycled paper is used as a raw material. The results to date show that, once thermally activated (in the range of 650-700°C), paper sludge turns out to be an alternative source of recycled metakaolin. This product is characterized by its high pozzolanic activity and improved performance with regard to the benefits of certain binary cements. The possibility of incorporating this industrial waste in cements along with other already standard pozzolans focuses, as mentioned, on the notable increase in the production of these types of cements. This is due, at present, to the extensive constructive applications for type-II cements (single additive) and to their lower economic and energetic costs that also makes them more suitable in times of economic crisis. In the present paper, the influence that pozzolan blends (activated paper sludge and fly ash) have on the reaction kinetics of ternary blended cements (6 and 21% of replacement) is evaluated, paying special attention to the identification and evolution of hydrated phases with increasing reaction times. The results obtained represent a pioneering research line at a global level and represent a starting point for future investigations because in the case of using paper sludge, release of CO2 from organic matter is very low and is listed as zero release. [ABSTRACT FROM AUTHOR]

A simple analytical model for calculating the nonlinear deformations of a corrugated core (fluting) during out-of-plane compression is developed. The results from the analytical model are compared to a more comprehensive finite-element model and to experiments. A connection between the boundary conditions and the damage state of the corrugated board is discussed. Including a modified set of boundary conditions gives an almost perfect match of the initial stiffness to the experimental results, indicating that the core might be significantly damaged as a result of the manufacturing process. Possibly, the strength of corrugated boards might be increased about 20% if one could avoid damaging the fluting during the manufacturing process. DOI: 10.1061/(ASCE)0733-9399(2007)133:11(1171) CE Database subject headings: Structural analysis; Finite element method; Deformation; Corrugating.

This paper aims at proposing a calculation model to deal with the face stability of shield tunnels in unsaturated soil. Based on the existing results of centrifugal test and numerical simulation, a new failure mechanism is proposed, which combines the logarithmic spiral with upper loosening arch mechanisms. The failure mechanism considers the influence of the soil arching effect and the logarithmic spiral height coefficient. Formulas for calculating the loosening earth pressure of unsaturated soil are deduced. Subsequently, this model of loosening earth pressure is introduced into an analytical model to compute the limit support pressure on the tunnel face. Compared with other height coefficients and the degree of soil arching effect, when the height coefficient is 0.95 and the degree of soil arching effect is 10%–30%, the limit support pressure proposed in this paper is in good agreement with the centrifugal test results. Finally, comparisons are performed with the proposed model and classical models as well as typical centrifuge model tests. The comparative analysis shows that the proposed theoretical model is in good agreement with the numerical simulation. The outline of the failure zone by the theoretical model in this paper is in good agreement with the centrifuge results. [ABSTRACT FROM AUTHOR]

She holds a B.Eng. in building engineering from Tongji University (2001), a M.S. in civil engineering from the University of Massachusetts (2005), and a Ph.D. in geotechnical engineering from the Georgia Institute of Technology (2010). Dr. Tan's areas of specialization include deep excavation and tunnelling, foundation engineering, forensic geotechnical engineering, and engineering failures associated with climate change. He received his B.Eng. in building engineering from Tongji University (1999), M.Eng. in Geotechnical Engineering from Tongji University (2002), and Ph.D. in civil engineering from the University of Massachusetts (2005). [Extracted from the article]

Because the original paper is not about the Millennium Tower case history, this argument has no direct relevance to the subject of the paper. We made no such inferences in the paper and refer interested readers to the case history paper for analysis of the degree to which consolidation was completed at different points in time in the Millennium Tower case study. While the Millennium Tower case history analysis provided the motivation and financial support for the broader study within which the testing program was undertaken, the paper under discussion does not present the case study, which was explained in its introduction. Both discussions lament that the paper did not present analyses of the Millennium Tower case history. [Extracted from the article]

This document discusses a research paper that explores the effects of relative density and particle morphology on the bearing capacity and collapse mechanism of strip footings in sand. The authors observe the development of shear zones during loading and question the behavior of two different sands tested in the study. They also discuss the combined effects of relative density and particle morphology on shear resistance. The document provides valuable insights and suggests further areas of investigation. The article concludes that relative density is not the primary factor influencing performance and suggests using laboratory strength tests to evaluate the effects of various factors on effective friction angles. The data from the study and previous research indicate that correlations between relative density and bearing capacity are not reliable for sands other than those studied. Instead, a more fundamental approach involves correlating foundation performance with mobilized effective friction angles. [Extracted from the article]

Soil reinforcement using synthetic fibers is a proven technique for enhancing engineering properties to meet the requirements of subgrade materials for pavement projects. The safe and economical design of fiber-reinforced pavement layers requires better insights into their unsaturated behavior. The soil–water characteristic curve (SWCC) is a measure of the water content inside soil pores at a given suction and is considered an essential property to better understand or predict the behavior of unsaturated fiber-reinforced soils. This paper centers on investigating the soil–water characteristic curves for typical expansive clay reinforced with two different types of polypropylene fibers having different surface morphological properties. The effect of an increase in the fiber dosage (0.2% and 0.6% by dry weight of soil) and fiber lengths (6 and 12 mm) on the resultant SWCC patterns is investigated. The addition of lime is considered to enhance the bonding between clay particles and fiber elements to ensure better friction mobilization levels. SWCCs were determined for all experimental mixtures using a combination of axis translation and filter paper techniques that cover the entire matric suction range during measurements. Volume changes undergone during suction measurements have been duly highlighted and discussed. Furthermore, the one-dimensional deformation (swelling/consolidation) characteristics of these lime-blended fiber-reinforced mixtures at different levels of initial matric suction are studied, and the correlations between initial matric suction with both compression index (Cc) and swell index (Cs) are established. The results indicate a significant change in the shape of the SWCC for lime-blended fiber-reinforced mixtures compared with the shape of the SWCC for natural clay. The contribution of fiber inclination to altering the shape of the SWCC curve is observed as slight regardless of the type, length, and dosage of fiber. Compression and swell indices for tested mixtures increased proportionately with an increase in initial matric suction levels. Doubling the length of the fiber also induced an increase in the compression index. Under no stress conditions did both fiber type and fiber length have a marginal effect on the swell potential and SWCCs. [ABSTRACT FROM AUTHOR]

Fine grid management is one of the important development directions of transportation planning that has not been fully considered in previous literature. This paper explores the application of the fine grid management method in transportation planning. Based on a case study of Chuanhui, China, this paper proposes a data-driven fine grid partitioning method for determining traffic analysis zones (TAZs). The TAZs are partitioned based on quadrilateral and hexagonal grids. This paper also summarizes a set of criteria for evaluating the impact of different fine grid partitioning methods based on the geographically and temporally weighted regression (GTWR) model. The results show that our fine grid partitioning method for determining TAZs based on quadrilateral grids can achieve a relatively low level of predicted value bias and variable correlation degree bias when the number of TAZs is larger, and it has obvious advantages. Finally, policy implications are proposed to promote the refinement of transportation planning. [ABSTRACT FROM AUTHOR]

This document is a closure to a previous paper titled "Foundation Settlement and Tilt of Millennium Tower in San Francisco, California." The authors respond to comments and questions raised by discussers regarding the design, construction, and analysis of the tower's foundation movements. They emphasize that their goal was to objectively document the data and provide interpretations of the soil deformation mechanisms that caused the settlements. They encourage further investigation and analysis of the case history to advance foundation engineering practices in dense urban environments. [Extracted from the article]

Studies the physical, economic and environmental feasibility of recovering energy from paper sludge in an institutional boiler. Emission rates measured during trial burns; Measurement of air emissions; Comparison of criteria pollutant emissions to wood chip emissions.

The pyrolysis kinetics of cellulosic uncoated printing and writing paper, which is one of the principal materials contributing to the municipal solid waste (MSW) of Taiwan, was investigated with a thermal gravimetric analysis (TGA) reaction system. The experiments were carried out in a nitrogen environment in the 450–850 K temperature range at various constant heating rates of 1, 2, and 5 K/min. The results indicated that there were two principal reactions in TGA curves as distinguished by the two significant and distinct mass changes over the experimental conditions. The pyrolysis of uncoated printing and writing paper can be adequately described by a two-reaction model. The corresponding activation energies, preexponential factors, and reaction orders were determined. The experimental results were satisfactorily fitted by the proposed chemical reaction model. [ABSTRACT FROM AUTHOR]

Citation data is increasingly being used to assess quality and importance. By this criterion, a paper that is not cited is automatically assumed to lack both quality and significance. This paper examines the validity of this hypothesis by reviewing citation rates of award-winning ASCE papers over a 25-year period from 1978-2002. In the study, citation data for seven civil engineering subdisciplines were obtained from the Science Citation Index developed by the Thomson Institute for Scientific Information (ISI). The analysis showed that nearly 25% of the award-winning papers were never cited with over 30% cited just once. Citations were higher in subdisciplines that are science based and lower in those that are more applied or specialist. These findings indicate that although citations provide a quantitative measure of use, they are imperfect indicators of quality and significance. [ABSTRACT FROM AUTHOR]

Energy saving has become a key concern of metro systems to reduce operating costs and meet the requirements of sustainable development. Energy-efficient timetabling, an effective way to reduce traction energy consumption, has gotten much attention in recent decades. However, limited research about energy-efficient timetabling simultaneously considered realistic speed profiles and the influence of train loads, which change greatly in different sections and significantly affect energy consumption. Therefore, this paper proposes an energy-efficient timetabling approach to improve regenerative energy utilization based on varying train loads and realistic speed profiles for bidirectional metro lines. First, based on the operational and safety constraints, this paper constructs an integer energy-efficient timetabling model where dwell times and nonuniform headways are taken as decision variables. Besides, the turnaround process is also considered to ensure rolling stock circulation efficiency. Sectional passenger volumes are employed to determine the varying train loads. Energy consumption is calculated based on realistic speed profiles. Owing to the complexity of the model, an improved adaptive large neighborhood search (ALNS) algorithm is designed to solve this model according to its characteristics. Finally, numerical examples are conducted based on the practical data from Shanghai Metro Line 17. The results indicate that the proposed approach effectively solves the energy-efficient timetabling problem with varying train loads and realistic speed profiles for bi-directional metro lines. The approach is suitable for off peak hours and can reduce energy consumption effectively, and the reduction is up to 11.9% for the presented cases. The improved ALNS algorithm can find good solutions within reasonable times in different cases. Moreover, compared with the widely used genetic algorithm in the literature, the improved ALNS algorithm is more efficient in solving the proposed energy-efficient timetabling problem in different cases. [ABSTRACT FROM AUTHOR]

Academics have been devoting a growing attention to different matters involving public-private partnerships (PPPs), and, as the use of PPPs for delivering infrastructure evolves worldwide, so does the number and type of papers addressing this procurement model. The objective of this paper is to undertake a comprehensive literature review of papers relating to PPPs and private finance initiatives (PFIs), using a bibliometric analysis. More than 600 papers published between 1990 and 2014 were examined. None of the previously existing studies analyzed such a large sample of papers. The research found that PPP studies appear to have a steady momentum toward growth. Engineering journals (and engineering as a research area) have been particularly active in this field. Authors based in Europe and Asia had written almost two-thirds of the papers, with transportation and health sectors at the top of sector-based papers. Most of the existing work is focused on aspects of contract design, risk sharing, and analyzing the contract performance and benefits, and neglects areas such as contract termination and renegotiation. The management of PPPs will be the next big challenge for PPP scholars and professionals. [ABSTRACT FROM AUTHOR]

One-layer (0.15-mm-thick) and 15-layer (5.43-mm-thick) graphene composites have been fabricated through the impregnation of epoxy resin into porous graphene nanoplatelet (GnP) paper. Three different flake sizes of GnPs were used for the 1-layer graphene com- posites: 5 μm, mixed 5 μm and 25 μm, and 25 μm. The largest graphene flakes showed the best material properties in terms of tensile strength and elongation at break. Both tensile and dynamic mechanical analysis (DMA) test results demonstrated that the 15-layer graphene composite had better material properties than the 1-layer graphene composites. The storage modulus of 15-layer graphene composite was 170% higher than that of neat epoxy. The transverse surface of 15-layer graphene composite exhibited a higher elastic modulus but lower hardness than the top surface. Ballistic limit test results showed that the combination of polyurea (PU) and a 15-layer graphene composite coating can increase the ballistic limit of TC-128 steel plate slightly. [ABSTRACT FROM AUTHOR]

The article offers tips on how to write an award-winning paper about engineering. According to the article, a prerequisite to writing a good paper is an in-depth understanding of the subject. This understanding should be beyond words and deep into concepts. To do this, one must have first-hand experience on the research that you are conducting.