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We numerically investigate the mechanisms that resulted in induced seismicity occurrence associated withCO2 injection at the Illinois Basin-Decatur Project (IBDP). We build a geologically consistent model that honors key stratigraphic horizons and 3D fault surfaces interpreted using surface seismic data and microseismicity locations. We populate our model with reservoir and geomechanical properties estimated using well-log and core data. We then performed coupled multiphase flow and geomechanics modeling to investigate the impact of CO2 injection on fault stability using the Coulomb failure criteria. We calibrate our flow model using measured reservoir pressure during the CO2 injection phase. Our model results show that pore-pressure diffusion along faults connecting the injection interval to the basement is essential to explain the destabilization of the regions where microseismicity occurred, and that poroelastic stresses alone would result in stabilization of those regions. Slip tendency analysis indicates that, due to their orientations with respect to the maximum horizontal stress direction, the faults where the microseismicity occurred were very close to failure prior to injection. These model results highlight the importance of accurate subsurface fault characterization for CO2 sequestration operations. [ABSTRACT FROM AUTHOR]

Constellations of satellites, in particular using small satellites, are very popular nowadays, because they give reduced costs and flexibility to missions. This paper considers the problem of designing a constellation of small satellites for data communication, which means getting data from platforms fixed on the surface of the Earth and sending them to ground stations using satellites. The goal is to maximize the observation times and minimize the interval between passages by these platforms and ground stations. The time evolution of the constellation under the effects of perturbation forces is also studied, and estimates of the number of new satellites that need to be added to the constellation to keep a constraint of maximum revisit time below one hour are made. After that, simulations of satellite failures allow verification of the new values for the observation times and the time between visits when the constellation loses some satellites, looking for the possibility of using this constellation even in case of failures. [ABSTRACT FROM AUTHOR]

In the contemporary landscape characterized by heightened competitive pressures, adept maintenance management assumes a pivotal and strategic role in cost mitigation and profit augmentation. This paper applies the risk-based maintenance (RBM) methodology to the hydraulic system of a remotely operated vehicle (ROV) owned by an oil and gas services company. To achieve this, it was necessary to gather information on the system failures, followed by determining the critical subsystems. By analyzing the frequency and severity of identified failures, a risk matrix could be constructed. Using the '5 Whys' technique, an analytical framework was used to uncover the root causes of the failures observed in the handlers and propellant subsystems. Subsequently, a risk matrix is formulated again after the implementation of the RBM and the mitigation measures adopted by the authors to elucidate the discernible impact of the maintenance methodology on improving the availability of the ROV and the incidence of failures outlined in the study.

The aim of this study was to investigate the causes of building failures in a part of Ilorin. Vertical electrical sounding (VES) was conducted, and 1D inverted resistivity indicates four distinct layers. The first layer is top soil with resistivity values of 16.1 Ωm to 81.1 Ωm and a depth of 0.1 m to 0.3 m. The second layer is clay/silty clay with resistivity values between 12.6 Ωm and 59.6 Ωm and a depth of 1.1 m to 2.8 m. The third geoelectric layer is weathered basement with resistivity values between 5.9 Ωm and 38.4 Ωm and a depth of 1.3 m to 6.2 m, and the fourth layer is fresh basement layer. Four pits were dug to a depth of 1.5 m, and undisturbed soils were collected for geotechnical test. Maximum dry density of the soils falls between 1.73 and 1.84 with an average of 1.90 Mg/m. Dynamic cone penetration test (DCPT) was conducted, and the quantity of blows to achieve 1000 mm (1 m) penetration depth (n) was recorded. DCPT of the soils varies between 89.8 kN/m2 and 314.3 kN/m2, with low bearing capacity of 89.8 kN/m2 to 134.7 kN/m2 at a depth of 0.1 m to 0.3 m, which is below the recommended minimum value of 150 kN/m2, and this contributed to the building failures in the study area.

This research presents the design and implementation of the preventive and predictive maintenance plan developed for the seven polishing machines of the Swedish multinational SKF, of the LSB (Large Size Bearing) line. Based on Reliability Centered Maintenance (RCM), which allows identifying the most relevant equipment for the process through a criticality analysis adopting strategies in order to eliminate the occurrence of failures. The methodology implemented in this research allowed the generation of maintenance tasks that facilitated the management and visualization of the information of each asset. The company provides maintenance services for large bearings used in cement plants, foundries and industrial material transport machines, seeking to optimize production methods and the application of this theoretical and analytical procedure allowed verifying that the conditioning services offered by the company are more efficient, demonstrating with figures the retribution of the plan. [ABSTRACT FROM AUTHOR]

In the contemporary landscape characterized by heightened competitive pressures, adept maintenance management assumes a pivotal and strategic role in cost mitigation and profit augmentation. This paper applies the risk-based maintenance (RBM) methodology to the hydraulic system of a remotely operated vehicle (ROV) owned by an oil and gas services company. To achieve this, it was necessary to gather information on the system failures, followed by determining the critical subsystems. By analyzing the frequency and severity of identified failures, a risk matrix could be constructed. Using the "5 Whys" technique, an analytical framework was used to uncover the root causes of the failures observed in the handlers and propellant subsystems. Subsequently, a risk matrix is formulated again after the implementation of the RBM and the mitigation measures adopted by the authors to elucidate the discernible impact of the maintenance methodology on improving the availability of the ROV and the incidence of failures outlined in the study. [ABSTRACT FROM AUTHOR]

This article delves into the techniques employed for identifying failures in hard disks through the utilization of machine learning algorithms. Hard disks serve as essential components within computer systems, and as they age and undergo repetitive usage, they may manifest indications of failure or inadequate performance, culminating in data loss and system malfunction. Consequently, the early detection and anticipation of hard disk failures are of utmost significance. Recent advancements in machine learning methods have enabled the precise detection of hard disk failures within a short timeframe. Within this investigation, we explore the foundational concepts pertaining to hard disks and their failures. We scrutinize various machine learning algorithms employed for the detection of hard disk failures. Furthermore, we introduce performance evaluation metrics for failure detection models. The challenges and limitations in the detection of hard disk failures are discussed, along with potential strategies for enhancing system performance and accuracy. [ABSTRACT FROM AUTHOR]

This research focuses on the dynamic landscape of today’s competitive market, where production management must meet clients’ expectations for high-quality products and shorter lead times while managing internal disruptions due to inevitable defects and unpredictable equipment failures. Achieving these operational goals without compromising product quality, missing deadlines, or experiencing production disruptions is essential for minimizing operational expenses. The study examines the dynamics of the system’s operating costs through the development of models, mathematical formulations, optimization techniques, and algorithm proposals. It demonstrates the system’s convexity and establishes the optimal batch time for implementing the proposed methodologies. The research results show relevant failure costs of 3.51 %, overtime added costs of 4.57 %, outsourcing setup costs of 0.73 %, outsourcing variable costs of 41.82 %, quality-related costs of 2.98 %, in-house variable costs of 40.42 %, and in-house holding costs of 3.55 %. The study develops strategies for optimal overtime use to meet production targets without excessive labor costs and provides a structured framework for making informed outsourcing decisions that balance cost savings with quality and reliability considerations. Overall, the research provides a robust framework for reducing operational costs while maintaining or improving the quality and reliability of manufacturing processes [ABSTRACT FROM AUTHOR]

This paper presents a risk assessment approach for analyzing the causes of malfunction-related main engine slowdowns. A fuzzy Bayesian Network-based methodology is used to assess the factors contributing to the engine's slow-down processes. The model addresses the complexity and uncertainty inherent in maritime operations with fuzzy sets where numerous interrelated factors can affect engine performance, and the Bayesian network to capture probabilistic dependencies. It considers various potential causes of the slow-down of ship engines that the manufacturer provides. Results demonstrate the model's ability to identify the influential factors leading to engine slow-down events and quantify the overall risk. Integrating fuzzy logic and Bayesian Networks comprehensively assesses relevant risk factors. It enables maritime stakeholders to manage engine performance and improves operational safety proactively. Findings can inform decision-makers, enabling the implementation of targeted maintenance strategies, fuel quality control measures, and crew training programs in the maritime industry. [ABSTRACT FROM AUTHOR]

Summary: After a machine failure, batch schedulers typically re‐schedule the job that failed with a high priority. This is fair for the failed job but still requires that job to re‐enter the submission queue and to wait for enough resources to become available. The waiting time can be very long when the job is large and the platform highly loaded, as is the case with typical HPC platforms. We propose another strategy: when a job J$$ J $$ fails, if no platform node is available, we steal one node from another job J′$$ {J}^{\prime } $$, and use it to continue the execution of J$$ J $$ despite the failure. In this work, we give a detailed assessment of this node stealing strategy using traces from the Mira supercomputer at Argonne National Laboratory. The main conclusion is that node stealing improves the utilization of the platform and dramatically reduces the flow of large jobs, at the price of slightly increasing the flow of small jobs. [ABSTRACT FROM AUTHOR]

Introduction Upper respiratory tract infections (URTI) are common and a common cause of sick-leave for healthcare workers, and furthermore pose a threat especially for patients susceptible to other diseases. Sufficient use of respiratory protective equipment (RPE) may protect both the workers and the patients. The COVID-19 pandemic provided a unique opportunity to study the association between use of RPE and URTI in a real-life setting. The aim of this study was to examine if failure of RPE or non-compliance with RPE guidelines increases the risk of non-COVID-19 URTI symptoms among healthcare workers. Methods In a longitudinal cohort study, we collected self-reported data daily on work tasks, use of RPE, and URTI symptoms among healthcare workers with patient contact in 2 Danish Regions in 2 time periods during the COVID-19 pandemic. The association between failure of RPE or non-compliance with RPE guidelines and URTI symptoms was analyzed separately by generalized linear models. Persons tested positive for severe acute respiratory syndrome coronavirus 2 were censored from the analyses. The 2 waves of data collection were analyzed separately, as there were differences in recommendations of RPE during the 2 waves. Results We found that for healthcare workers performing work tasks with a risk of transmission of viruses or bacteria, failure of RPE was associated with an increased risk of URTI symptoms, RR: 1.65[0.53–5.14] in wave 1 and RR: 1.30[0.56–3.03] in wave 2. Also non-compliance with RPE guidelines was associated with an increased risk of URTI symptoms compared to the use of RPE in wave 1, RR: 1.28[0.87–1.87] and wave 2, RR: 1.39[1.01–1.91]. Stratifying on high- versus low-risk tasks showed that the risk related to failure and non-compliance was primarily associated with high-risk tasks, although not statistically significant. Discussion The study was conducted during the COVID-19 pandemic and thus may be affected by other preventive measures in society. However, this gave the opportunity to study the use of RPE in a real-life setting, also in departments that did not previously use RPE. The circumstances in the 2 time periods of data collection differed and were analyzed separately and thus the sample size was limited and affected the precision of the estimates. Conclusion Failures of RPE and non-compliance with RPE guidelines may increase the risk of URTI, compared to those who reported use of RPE as recommended. The implications of these findings are that the use of RPE to prevent URTI could be considered, especially while performing high-risk tasks where other prevention strategies are not achievable. [ABSTRACT FROM AUTHOR]

In an internal combustion (IC) engine, the failure of engine parts due to friction and wear is a serious issue. This can be reduced by employing suitable surface modification techniques such as thermal barrier coatings, laser-assisted surface engineering techniques, carbon nanotubes, etc. These techniques help to decrease the frictional forces and improve the tribological, mechanical and corrosion-resistant properties of the engine components. This paper highlights the distinct causes of the failure of engine parts and the role of different surface modification techniques in improving the tribological and mechanical properties of the engine parts. After that, the preventive measures for engine parts failure including online condition monitoring and maintenance strategies are presented. Finally, the future scope and challenges are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Zeszyty Naukowe KUL is the property of John Paul II Catholic University of Lublin, Wydawnictwo KUL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a reliability modelling of a two-unit ammonia/urea plant. Real maintenance data of the production plant have been used for this purpose. Four types of failure were noted: process, electrical, mechanical and instrumental failures. Both ammonia/urea formation units work in parallel and do not fail simultaneously. Various reliability indices of the plant, such as availability, busy period for repair, and expected number of repairs for each type of failure, have been obtained. Markov processes and regenerative point techniques are used for analysis. Profit analysis for the plant is also done, along with a graphical representation of various parameters. Finally, sensitivity analysis is carried out to see the impact of varied parameters on the profit function of the plant. [ABSTRACT FROM AUTHOR]

This research presents the design and implementation of the preventive and predictive maintenance plan developed for the seven polishing machines of the Swedish multinational SKF, of the LSB (Large Size Bearing) line. Based on Reliability Centered Maintenance (RCM), which allows identifying the most relevant equipment for the process through a criticality analysis adopting strategies in order to eliminate the occurrence of failures. The methodology implemented in this research allowed the generation of maintenance tasks that facilitated the management and visualization of the information of each asset. The company provides maintenance services for large bearings used in cement plants, foundries and industrial material transport machines, seeking to optimize production methods and the application of this theoretical and analytical procedure allowed verifying that the conditioning services offered by the company are more efficient, demonstrating with figures the retribution of the plan.

This paper attempts to solve the problem of identifying the critical factors of road design on human driver (HD) accidents and automated vehicle (AV) failures. This study is of immediate importance for the safety of the road, which must facilitate the wide emergence of commercialized vehicle automation technologies. We overcome the weakness of the current literature that relies on simulation to capture the safety of the road for AVs, by using real-world field data. We drive commercially available vehicles with driving automation technologies and collect data on their driving failures on the real road network of South Korea over a span of 6,730 kilometers. We additionally gather data on detailed road geometry like road curvature and road width, traffic operation, and HD accidents for the same roads. We implement a machine learning method to predict if a given road link has had any HD accidents and AV failures. A cross-validation experiment shows high prediction accuracy for HD accidents around 94% and for AV accidents around 82%, despite the unbalanced dataset on safe and unsafe road links. Moreover, the machine learning results are interpreted with Shapley Additive exPlanation method, and we identify critical safety factors of road geometry and operation that are common and distinct for the HDs and AVs. We find that the safety of human-driven and AVs are both affected by the traffic operation variables, such as the traffic speed and volume during peak and non-peak hours. However, AV failures are affected by road geometry, such as road curvature, road width, and spacing between streetlights, more than the HD accidents. AVs are safer in road links with higher speed limits than HDs. Also, AV failures are affected differently by structures, such as shock absorbers and junctions, to the HD accidents. From these findings, we provide policy recommendations on the safe road design for both HDs and AVs.

The bending behavior of one-war reinforced concrete (RC) slabs with polypropylene fibers (PF) was examined in this study under the effect of different opening ratios using the nonlinear finite element analysis (NLFEA) method. The investigated parameters include the effect of different square opening ratios between 0 and 24% and PF volume percentages between 0 and 1% with 0.1% increments. The objectives of this study were fulfilled using 88 NLFEA models with different combinations of the studied parameters, including 11 control slabs without openings. The slab's behavior was studied focusing on different structural performance characteristics, such as ductility, using energy-based and deflection-based approaches, stiffness (initial and yielding), cracking, and ultimate load strength. In addition, other structural performance parameters were considered, such as the crack opening, failure modes, and strain values, which were recorded for all specimens during the loading history. Moreover, the load-carrying capacity of the slabs was compared, looking at the NLFEA method's results and the theoretical prediction results based on the sectional analysis method. However, it was observed that the inclusion of PFs of different percentages has a superior effect on the behavior of RC slabs with small openings (less than 2% opening ratio) compared to the acceptable improvements obtained for sabs with larger opening sizes. Consequently, PF could be utilized as a replacement for conventional steel rebars for RC slabs with small openings. In addition, increasing the PF percentage increases the resulting crack-opening value at failure due to the provided stabilization effect, in addition to increasing the system's ability to sustain loads. [ABSTRACT FROM AUTHOR]

Concentrating solar power plants use sensible thermal energy storage, a mature technology based on molten salts, due to the high storage efficiency (up to 99%). Both parabolic trough collectors and the central receiver system for concentrating solar power technologies use molten salts tanks, either in direct storage systems or in indirect ones. But even though this is a mature technology, it still shows challenges in its implementation and operation. This paper underscores the critical importance of stringent design criteria for molten salt tanks in thermal storage technology. Focusing on the potential ramifications of design failures, the study explores various dimensions where an inadequate design can lead to severe consequences, even jeopardizing the viability of the entire technology. Key areas discussed include structural integrity, corrosion, thermal shock, thermal expansions, and others. By elucidating the multifaceted risks associated with design shortcomings, this paper aims to emphasize the necessity of thorough reviews and adherence to robust design principles for ensuring the success, safety, and sustainability of thermal storage technology. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Serious damage to near-fault structures is caused mainly by velocity pulses in a ground motion, hence, the necessity to develop a pulse-related definition of strong-motion duration to adequately describe the intensity of near-fault ground motion. For a multipulse record, an ideal-pulse-based strong-motion duration, which is defined as the time interval between the beginning of the first pulse and the end of the last pulse in an ideal-pulse signal, is proposed. This strong-motion duration corresponds with the time interval of the occurrence of strong vibrations and energy accumulations in the original record. For near-fault records, pulselike characteristics can be completely presented within this duration. Meanwhile, the ideal-pulse-based strong-motion duration shows good performance in the estimation of structural responses. The elastic and inelastic displacement spectra of the original records agree well with those of the records shortened according to the proposed duration. The validity of applying the proposed duration to structural analysis is further verified by the nonlinear time history analyses of 3-, 9-, and 20-story steel moment-resisting frame structures. The proposed strong-motion duration accurately estimates nonlinear structural responses. It is proven that the ideal-pulse-based strong-motion duration can adequately describe the intensity of near-fault ground motions, both from the perspective of the energy accumulation process in a ground-motion record and that of the structural analyses subjected to these ground motions. [ABSTRACT FROM AUTHOR]

How does an earthquake affect buried pipeline networks? It is well known that the seismic performance of buried pipelines depends on ground failures (GFs) as well as strong ground shaking (SGS), but it is unclear how the various types of earthquake hazards should be collectively combined, as existing methodologies tend to examine each of the earthquake hazards separately. In this article, we develop a probability-based methodology to consistently combine SGS with three types of GF (surface faulting, liquefaction, and landslide) for forecasting seismic damage in buried pipeline networks from a given earthquake rupture scenario. Using a gas transmission pipeline example, we illustrate how the proposed methodology enables others (e.g., researchers, pipeline operators who manage distribution lines, and consultants) to modularly combine various models such as those for estimating probability of GF, permanent ground displacements, and pipeline fragility. Finally, we compare the proposed methodology against the Hazus methodology to explore implications from considering each hazard one at a time. [ABSTRACT FROM AUTHOR]

Objectives: To examine the impact of bisphosphonates (BPs) on dental implant treatment and alveolar bone in post-menopausal ladies. Materials and Methods: Twenty post-menopausal ladies who had at least one dental implant within the previous 5 years participated in the current study. Ten subjects were categorized into two groups: Group A had BP medication for 1.5 years, and group B received parathyroid hormone (PTH). Both groups' bone thickness and bone mineral density (BMD) were measured. Result: Group A had 5%, and group B had 5% of dental implants failures. BMD of cortical bone was 1468 ± 136 mg/mL and 1008 ± 84 mg/mL in groups A and B, correspondingly. The cortical and cancellous bone densities in both the groups were statically significant. Cortical bone thickness was insignificant in comparison. Conclusion: Both cortical and cancellous bones' bone mineral density decreased in both groups. With continued usage of BPs, the cortical bone thickness increased.

Abstract Slopes are built for the purpose of extracting ore, in the case of mining, or access roads in civil works. The excavation of slopes in tropical countries is facilitated by the thick layer of soil formed from the more intense weathering when compared to other countries. However, the residence time of water in the soil is relatively longer and consequently allows the accumulation and percolation of water through rock fractures even in the dry period. These factors induce a greater probability of occurrence of ruptures. Mines in the decommissioning phase must guarantee slope stability conditions even after closure in order to comply with legislation and environmental safety. In this work, the slopes of a decommissioning mine were investigated using geophysical methods (GPR) and structural analysis of the rock mass. The results were presented in the form of radargrams that correlate distance and depth of investigation. Structural data served as the basis for the execution of kinematic analyzes for planar and wedge ruptures. The analysis of the results allowed the correlation between electromagnetic signal attenuation zones, with the presence of water and the occurrence of ruptures. Thus, the GPR results allowed the recognition of structural discontinuities, accumulation zones and water flow.

The use of batteries in electric cars comes with inherent risks. As the crucial component of these vehicles, batteries must possess a highly dependable safety system to ensure the safety of users. To establish such a reliable safety system, a comprehensive analysis of potential battery failures is carried out. This research examines various failure modes and their effects, investigates the causes behind them, and quantifies the associated risks. The failure modes and effect analysis (FMEA) method is employed to classify these failures based on priority numbers. By studying 28 accident reports involving electric vehicles, data is collected to identify potential failure modes and evaluate their risks. The results obtained from the FMEA assessment are used to propose safety measures, considering the importance of the potential failure modes as indicated by their risk priority number (RPN). The design incorporates safeguards against mechanical stress, external short circuits, and thermal runaway incidents. The findings of this study enhance our understanding of electric vehicle (EV) battery safety and offer valuable insights to EV manufacturers, regulators, and policymakers, aiding them in the development of safer and more reliable electric vehicles.

The efficiency of a mining and processing plant depends on the level of complex mechanization of the production process. In mineral extraction, haulage is a major cost category, with haul trucks being the key component of the mining transportation system. To improve production performance, mining operations can increase their haulage turnover and reduce transportation costs, which necessitates making haul trucks more reliable. This can be done by improving their mean time to first failure (MTFF) indicators. This article analyzes the reliability status of the traction drive system inhaul trucks operating in the mineral resources sector. It provides a quantitative assessment of traction drive system failures resulting from part defects and discusses the associated repair costs. By examining failure data from 2018 to 2022 and the results of vibration tests performed on a diesel generator, the study reveals that the most expensive failures are associated with defects in the synchronous generator, which are primarily caused by elevated external vibrations. Based on basic vibration tests and vibration spectra tests at different operating modes, recommendations have been formulated concerning the generator’s robustness to external mechanical forces and the ways to increase the generator’s protection grade to prevent dust intrusion. The study also identifies the frequency range that poses the greatest risk of damage to the windings.

Abstract Backgrounds Long-span dental bridges may cause excessive load on abutment teeth and the periodontal area, which may lead to bridge fractures or periodontal problems. However, some reports have revealed that short- and long-span bridges can provide a similar prognosis. This clinical study aimed to investigate the technical complications associated with fixed dental prostheses (FDPs) of different span lengths. Methods All patients with previously cemented FDPs were clinically examined during their follow-up visits. Several data related to FDPs were registered, such as design, material type, location, and type of complication. The main clinical factors analyzed were technical complications. Life table survival analyses were performed to calculate the cumulative survival rate of FDPs when technical complications were detected. Results The study examined 229 patients with a total number of 258 prostheses and an average of 98 months of follow-up. Seventy-four prostheses suffered from technical complications, and the most common complication was ceramic fracture or chipping (n = 66), while loss of retention occurred in 11 prostheses. The long-term evaluation of long-span prostheses revealed a significantly higher technical complication rate compared to short-span prostheses (P = ,003). The cumulative survival rate for short-span FDPs was 91% in year 5, 68% in year 10, and 34% in year 15. For long-span FDPs, the cumulative survival rate was 85% in year 5, 50% in year 10, and 18% in year 15. Conclusion Long-span prostheses (5 units or more) can be associated with a higher technical complication rate compared to short-span prostheses after long-term evaluation.

Nowadays, additive manufacturing (AM) has surpassed traditional machining in the realm of emerging manufacturing. In the case of conventional machining, where the material is removed by different processes (subtractive manufacturing), there is a possibility of warping and internal stress development. Rapid prototyping is another option to avoid all the drawbacks of conventional machining in terms of manufacturing cost, time, accuracy, and quality. Rapid prototyping of a product by adding material (additive manufacturing) is gaining commercial traction. Additive manufacturing is frequently employed for the fabrication and bulk customization of all kinds of intricate geometrical designs those are absurd by traditional manufacturing techniques. Additive manufacturing techniques are broadly divided into four categories: (a) material extrusion, (b) chain polymerization, (c) laser or electron beam assisted sintering, and (d) direct writing-based processes. This article is a cutting-edge review that focuses on additive manufacturing processes and materials used in additive manufacturing. The process parameters for experimentation are chosen based on the application for which the part is designed. Some input process factors influence others for a specific response, and these critical process parameters are identified and optimized. This paper also gives a synopsis of failures associated with some additive manufacturing methods and their preventive actions.

Over the past few decades, Lab-on-a-chip (LoC) devices have made health diagnostics easier and cheaper by enabling rapid, hassle-free, and inexpensive measurements of different biochemical markers, properties of epidermally retrievable biofluids (e.g., sweat and interstitial fluids), etc. The miniaturization of these sensing technologies along with the integration of flexible frameworks (microfluidic assemblies and electronics) and user-friendly software have paved the way for autonomous and continuous tracking of human health parameters. However, with emerging new technologies, there are new and complex challenges, especially in the case of these miniature LoC devices. Although microfluidics-specific challenges such as analyte contamination, flow rate variability, improving detection specificity, etc. are being worked upon, the bigger question is: how reliable are these wearable devices in the long run? This perspective piece initially talks about the state-of-the-art LoC technologies that have been incorporated into wearable devices. Next, the perspective identifies some of the reliability studies conducted (as well as overlooked) on the integrated wearable electronics used. Finally, the paper discusses the challenges and future directions of research in the field of reliability of LoCbased wearable electronics. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Production Engineering / Revista Brasileira de Engenharia de Produção is the property of Brazilian Journal of Production Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tailings dams have relatively high failure rates throughout the world and the consequences of these failures often result in significant loss of life and damage to the environment and property. However, the triggers and failure mechanisms are typically hypothesized and not well understood. To investigate potential triggers and the corresponding failure mechanisms, two centrifuge model tests were conducted on loose slopes made of gold tailings using a scaled viscous fluid to induce instability in flight. A numerical back-analysis was also carried out to investigate and verify the associated mechanisms. Two failure mechanisms were observed in the centrifuge tests. In the first test, large seepage forces caused sloughing at the toe. The initially drained instability at the toe induced significant positive excess pore pressures due to the loose state, as well as to the initially higher degree of saturation in the toe region, triggering localized liquefaction at the toe (undrained response). Due to the localized liquefaction, the tailings at the toe could not support the tailings upstream of the toe, triggering a retrogressive flowslide failure. In the second test, a slope failure occurred due to drained instability, i.e., failure occurred once the drained factor of safety approached unity. No liquefaction was evident, due to the initially lower degree of saturation in the toe region, as well as to the slower rate of shearing compared to the first test. As revealed by both physical and numerical simulations, the structural collapse of the soil resulted in the drained instability of the slope, which triggered a slide-to-flow failure. [ABSTRACT FROM AUTHOR]

Slopes are built for the purpose of extracting ore, in the case of mining, or access roads in civil works. The excavation of slopes in tropical countries is facilitated by the thick layer of soil formed from the more intense weathering when compared to other countries. However, the residence time of water in the soil is relatively longer and consequently allows the accumulation and percolation of water through rock fractures even in the dry period. These factors induce a greater probability of occurrence of ruptures. Mines in the decommissioning phase must guarantee slope stability conditions even after closure in order to comply with legislation and environmental safety. In this work, the slopes of a decommissioning mine were investigated using geophysical methods (GPR) and structural analysis of the rock mass. The results were presented in the form of radargrams that correlate distance and depth of investigation. Structural data served as the basis for the execution of kinematic analyzes for planar and wedge ruptures. The analysis of the results allowed the correlation between electromagnetic signal attenuation zones, with the presence of water and the occurrence of ruptures. Thus, the GPR results allowed the recognition of structural discontinuities, accumulation zones and water flow.Article Highlights: The radargrams obtained with the GPR clearly identified saturated and unsaturated zones of the rock mass; The radargrams identified existing fractures inside the rock mass consistent with those verified on the face of the slope. GPR has proven to be a subsurface analysis tool to be used in both mining and civil works. [ABSTRACT FROM AUTHOR]