Search Results (40)

This article presents the issue of energy waste in manufacturing processes, focusing on reducing unnecessary energy consumption and CO₂ emissions. A significant challenge in modern production is identifying and minimizing energy waste, which not only increases operational costs but also contributes to environmental degradation. An improvement methodology referred to as 2E-DAmIcS is proposed. A distinguishing feature of the methodology is a risk map of energy waste in the production process. Application of the methodology is demonstrated using the example of a lead–acid battery production process. It is shown that even small but well-diagnosed changes to the process make it possible to significantly reduce energy consumption. The proposed methodology offers practical tools for managers and decision-makers in various industries to systematically identify and minimize energy waste. It highlights the importance of cross-disciplinary collaboration among specialists in technology, energy consumption, and statistical analysis to optimize energy use. By applying this approach, companies can achieve both financial savings and environmental benefits, contributing to more sustainable production practices. Full article

The reliability and durability of integrated circuits (ICs), present in almost every electronic system, from consumer electronics to the automotive or aerospace industries, have been and will continue to be critical concerns for IC chip makers, especially in scaled nanometer technologies. In this context, ICs are expected to deliver optimal performance and reliability throughout their projected lifetime. However, real-time reliability assessment and remaining lifetime projections during in-field IC operation remain unknown due to the absence of trustworthy on-chip reliability monitors. The integration of such on-chip monitors has recently gained significant importance because they can provide real-time IC reliability extraction by exploiting the fundamental physics of two of the major reliability degradation phenomena: bias temperature instability (BTI) and hot carrier degradation (HCD). In this work, we present an extensive study of ring oscillator (RO)-based degradation and annealing monitors designed on our latest 28 nm versatile array chip. This test vehicle, along with a dedicated test setup, enabled the reliable statistical characterization of BTI- and HCD-stressed as well as annealed RO monitor circuits. The versatility of the test vehicle presented in this work permits the execution of accelerated degradation tests together with annealing experiments conducted on RO-based reliability monitor circuits. From these experiments, we have constructed precise annealing maps that provide detailed insights into the annealing behavior of our monitors as a function of temperature and time, ultimately revealing the usage history of the IC. Full article

Over the past two decades, rapid climate change has severely impacted people’s lives globally, affecting their safety and sustainability. Water, a vital human resource, has been severely affected, with drought and high temperatures leading to desertification, the drying up of rivers and lakes, spontaneous fires in forests, and massive floods and torrents due to melting ice and rising sea and ocean surface water levels. The expected impacts of climate change on the Nile, Egypt’s primary water source, are significant. These impacts can vary across regions, depending on factors like local climate, socio-economic dynamics, topography, and environmental nature. Upper Egypt, characterized by arid and semi-arid regions, faces water scarcity and socio-economic development challenges. Climate change exacerbates these issues, posing significant threats to the region’s ecological sustainability and socio-economic development. Therefore, it is crucial to address these impacts to ensure the Nile’s continued vitality and sustainability. The study aims to analyze the climate change data over the past few decades, analyze its characteristics, and model its effects on Upper Egypt’s water sources. The study expected a big decrease in the water resources of the Nile. While what is currently occurring in terms of fluctuating rainfall rates between scarcity and severity contradicts the results of those studies, that is the best evidence of the need for further research and studies to obtain more reliable and consistent results with the reality that it may help decision-makers to develop scenarios to manage climate change effectively, preventing or reducing negative effects, and finding suitable alternatives. Studies predict a 10% decrease in Nile revenue at Aswan High Dam Lake by 2095, with some predicting a 30% increase. This lack of credibility underscores the need for more comprehensive studies. Full article

Ice consumption has widely increased over the last decade. Cases of ice contamination by various microorganisms (bacteria, viruses and fungi) have been documented in the literature. In this review, we summarize the findings of selected articles on the hygienic and sanitary quality of food ice from 1 January 2013 to 31 December 2023. A total of 14 articles found via the PubMed search engine during the study period were reviewed. From the comparison between the ice produced on an industrial scale and the ice produced on a local scale in food businesses, the latter was found to be more contaminated by microorganisms. The most detected bacteria included Escherichia coli, coliforms, Pseudomonas spp., Staphylococcus aureus; three studies evaluated the presence of Vibrio cholerae and Vibrio parahaemolyticus; two studies highlighted the presence of viruses (Rotavirus and Norovirus). Finally, two studies detected the presence of fungi (molds and yeasts). Almost all authors of the studies argued that ice contamination also depends on the hygienic–sanitary quality of the ice-making machines. The results show that the information currently available in the literature on the hygienic–sanitary quality of ice is incomplete and that future national and international scientific studies need to be carried out. Full article

This study investigates the interconnected dynamics among the Dow Jones Sustainability World Index and two volatility indexes, the Cboe Volatility Index and ICE BofA MOVE Index. It examines their relationships and causalities within daily data spanning from January 2014 to July 2023. The research employs wavelet power spectrum (WPS) and wavelet coherence analyses (WCA) to delve into these interconnections. The wavelet power spectrum reveals noteworthy volatility spikes in the indexes during specific periods linked to geopolitical occurrences, the COVID-19 pandemic, and global uncertainties. A wavelet coherence analysis unveils how the DJ Sustainability World Index significantly influences the Cboe Volatility Index and ICE BofA MOVE Index across short, medium, and long-term perspectives, albeit with variations in certain periods. The empirical findings underscore the intricate relationships between sustainability and volatility indexes, shedding light on their nuanced causal interplay over time. The insights from this study hold paramount implications for policy-makers, investors, and financial institutions navigating a complex and uncertain landscape. The identified relationships between sustainability and market volatility can aid in making informed decisions. This research adds original value by uncovering the time-varying relationships between sustainability and volatility indexes, revealing their interdependencies across diverse temporal scales. Given the observed causal relationships, policy-makers and investors are recommended to consider sustainability-related developments when assessing market volatility. This proactive approach can lead to more informed decision making and effective risk management strategies. Full article

During curling sports, the movement of the stone is affected by the quality of the ice. Therefore, the delivery team led by the ice maker hopes that the quality of the ice surface will be stable and that the athletes will always ‘read the ice’ and pay attention to the small changes in the ice surface. This phenomenon is the charm of curling. Many friction models have been proposed to describe the regularity of the curling motion. In the curling competitions of the 2022 Beijing Winter Olympic Games, the 2021 World Wheelchair Curling Championships, and the warm-up competition before, the research team installed a video image capture system in the arena to capture and record the data of the curling motion by using the depth neural network and object tracking algorithm. Further motion data research verifies the relationship between the friction coefficient and the speed. The quality control parameter of ice rink α is proposed, which is related to the influencing factors of the ice surface temperature, the ice hardness, the size of the pebble point, and the width of the curling friction band. The quality of the curling ice rink can be evaluated accurately and comprehensively by using parameter α. Based on the relationship between the friction coefficient and the speed, a physical model of horizontal sliding of the curling stone is established, which agrees well with the results of data obtained from video acquisition. Therefore, the movement distance along the rink can be accurately predicted. This paper analyzes the relationship between the long-time (the time it takes for the curling stone to travel between the two hog lines) and the stop position and that between the long-time and the split-time (the time it takes for the curling stone to travel from the back line to the hog line). Based on this result, a ruler can be established to assist athletes in estimating the sliding distance of the stone before curling throwing. This research also studies the relationship between three factors (the sliding speed in the x-direction, the angular speed, and a tiny lateral deflection speed in the y-direction) and the deviation of the stone. At the same time, there are also some interesting phenomena of the lateral deflection of the stone, such as the relationship between the lateral deflection angle tanθ and the initial lateral speed. As a result, the prediction of the curling stone’s exact final location can be realized. In summary, this article proposes an indicator for evaluating the quality of ice rinks and a physical model of curling based on the curling friction model, which is validated by data obtained from a video capture system of the 2022 Beijing Winter Olympics. The results described above have been applied in the post-match operation of the National Aquatics Center to guide the production of Olympic-grade ice surfaces and to guide athletes to “read ice” accurately during training. Full article

The lack of an EV charging infrastructure is of the top five barriers preventing the adoption of EVs on a large scale. A long charging time is also one of the five barriers, according to the latest survey published by the IEA in 2021. The estimated increase in demand for EVs is a big challenge in many countries all around the world. This challenge exists in many EU and Middle East countries. The main reason for this problem is the requirement of huge funds to install enough public charging points that result in satisfactory charging services. Hence, the phase-out plans of internal combustion engine (ICE) vehicles can be carried out successfully and smoothly. Unfortunately, there is a trade-off between the cost of installing charging points and EV charging time. Therefore, it is important to optimize both factors simultaneously. This way, the charging services can be provided at the minimum possible cost and at a satisfactory level of quality. This study determines the optimum ratio of the number of chargers to the number of EVs in a certain province. The optimal number of chargers that are necessary to optimally serve a certain number of EVs has been determined. Two well-known evolutionary search techniques have solved the optimization problem: particle swarm optimization (PSO) and genetic algorithms (GA). Both algorithms have succeeded in providing many optimal charging infrastructure scenarios. Hence, the decision maker can select the most convenient scenario from several alternatives based on the available budgets and the most convenient charging time. Full article

This paper evaluates the effect of intellectual capital (IC) on firm financial performance in the service sector in an emerging country, Vietnam. This research is dissimilar from earlier ones for the following reasons: (i) this is the first study of IC’s impact on service firms at different knowledge intensity levels, sizes, and ownerships in an emerging country, Vietnam; (ii) it expresses empirical evidence in details of service activities, particularly the research and development, financial, and technology services that play significant roles for the development of emerging countries; (iii) it examines the effects of the gender issue, firms’ responsiveness to the government and employees, and market concentration. Applying the two-step system GMM model for the period 2005–2014, the results express that IC components generally had significant impacts on firm performance. Human capital efficiency had the strongest positive impact while capital employed efficiency had the second strongest impact. The impact of structural capital efficiency was inconsistent, depending on the knowledge intensity levels and the types of service activities. IC is more efficient for knowledge-intensive sub-sectors than the less knowledge-intensive ones. IC efficiencies differ among knowledge intensity levels, sizes, and ownerships, suggesting that policy makers and firm leaders should implement corresponding solutions. Full article

To prolong the fatigue life of a product handled by machines such as refrigerators and agricultural machinery, parametric accelerated life testing (ALT) is recommended as a systemized approach to detect design inadequacies and reduce fatigue. It demands (1) an ALT strategy, (2) a fatigue type, (3) parametric ALTs with change, and (4) an estimate of whether the present product completes the BX lifetime. The utilization of a quantum-transported life-stress type and a sample size are advocated. The enhancements in the lifetime of a refrigerator ice-maker, containing an auger motor with bearings, were employed as a case study. In the 1st ALT, a steel rolling bearing cracked due to repeated loading under cold conditions (below −20 °C) in the freezer compartment. The bearing material was changed from an AISI 52100 Alloy Steel with 1.30–1.60% chromium to a lubricated sliding bearing with sintered and hardened steel (FLC 4608-110HT) because of its high fatigue strength at lower temperatures. In the 2nd ALT, a helix made of polycarbonates (PCs) fractured. In the redesign, a reinforced rib of the helix was thickened. Because no troubles in the 3rd ALT happened, the life of an ice-maker was proven to have a B1 life 10 years. Full article

The ice-making process is an important factor that affects the ice quality and the energy consumption of ice rinks. An unsteady heat transfer model is established and validated for the ice-making process. The transient temperature variation and ice thickness growing characteristics during the ice-making process are analyzed. The freezing time of a water layer and the final temperature of the stabilized ice layer are quantified. The effects of ice rink structural parameters on the ice-making process are studied. The results show that the water temperature variations during the process go through three stages. The ice-growing process mainly occurs in the second stage. The ice-making process takes about 305 min–420 min for a water layer of 5 mm thickness. The reduction in the ice-making time and the decrease in the final temperature of the stabilized ice layer can be attained by reducing the water layer thickness, the surface heat flux, the cooling pipe spacing, the fluid temperature in the cooling pipe, or the top concrete thickness. Among them, the influences of the thickness of the water layer, the surface heat flux, and the fluid temperature in the cooling pipe are more significant. As the thickness of the water layer decreases from 7 mm to 3 mm, the total ice-making time decreases by about 37.6%. The ice-making time is reduced by 17.1% with the surface heat flux decreasing from 330 W/m² to 250 W/m². The ice-making time is reduced by 21.4% with the cooling pipe temperature decreasing from −15.5 °C to −19.5 °C. Full article

Adsorption refrigeration systems are one of the emerging decarbonization technologies that can use eco-friendly heating sources and working fluids. However, the highly porous adsorbent materials used in these systems have a low thermal conductivity that hinders their system performance enhancement. Graphene nanoplatelets are proposed in the literature to improve the conductive heat transfer through the adsorbent field and the resulting composite adsorbents were favorably testified at the material level. In this study, the impact of employing a composite adsorbent that comprises of 50% activated carbon type Maxsorb III, 40% graphene nanoplatelets, and 10% binder was numerically investigated at a system level. The contradictory effects of heat and mass transfer mechanisms within the composite adsorbent on the performance of an adsorption ice production system were explored for three cases of composite layer thicknesses at different cycle times. The results showed that the maximum specific daily ice production and coefficient of performance of 33.27 kg_ice·kg_ads⁻¹·day⁻¹ and 0.3046 were attained at composite thicknesses of 2 and 5 mm and cycle times of 430 and 1230 s, respectively. The higher composite thickness of 10 mm increased the mass transfer resistances, which overlooked the enhancement in the heat transfer and reduced the overall performance. Full article

This investigation practically explains the implementation of parametric accelerated life testing (ALT) as an algorithm to recognize design imperfection and rectify it in creating a reliable quantitative (RQ) statement by sample size equation. It covers: (1) a module BX life that X% of a collection of system items is unsuccessful with an ALT plan, (2) design for fatigue, (3) ALTs with alterations, and (4) discernment as to if the final design(s) obtains the targeted BX lifetime. A (generalized) life–stress formulation by the linear transport process is recommended for the mathematical work of the parametric model. As a case study, an ice-maker including gear system in a refrigerator was utilized. The gear teeth made of cast iron (carbon, 3 wt% and silicon, 2 wt%) was fracturing in a refrigerator ice-maker. To reproduce the field failure and rectify the problematic designs in the marketplace, a parametric ALT was carried out. At the first ALT, the gear teeth made of cast iron partly cracked and fractured under severe cold conditions (below −20 °C) in the freezer. It was modified by changing the material from cast iron to a sinter-hardened powder metallurgy nickel steel because high fatigue strength in the low temperature was required. At the second ALT, we discovered the fractured helix made of polycarbonates (PC). As a modification, strengthened rib on the front and side of the helix the thickness of gear teeth was attached. At the third ALT, there was no concern, and the life of the auger motor including gear system was manifested to have a B1 life 10 years. Full article

A well-known landslide dam that collapsed and generated a large outburst flood is used to show the importance of forensic geology analysis, which is the on-site multidisciplinary study of geohazards carries out as soon as possible after their occurrence; this study is focused on understanding the complete spectrum of all mechanisms that caused the disaster. Diagnostic elements of all natural processes fade with time, allowing for progressively divergent interpretations that may impact the appropriateness of potential mitigation actions, as we demonstrate. The multidisciplinary field control of the abrupt rupture of a natural dam on the Santa Cruz River on 12 November 2005, that released c. 37 million m³ of water and sediment, can radically change the interpretation of how this dam collapsed. In situ sedimentological, geomorphological and topographical analyses of the remains of the collapsed natural dam suggest it was built in two mass-wasting episodes instead of one, as previously interpreted, involving different slide materials. The first episode matches previous interpretations; a landslide that evolved into a rock avalanche, generating an initial dam of high stability due to its density, and observed angles of repose. This dam was not removed completely during the rupture, but rather suffered minor erosion at its top by the flood drag effect. The second episode is interpreted as a snow-dominated mixed avalanche, reaching much greater heights on the opposite side of the valley. This avalanche is estimated to be 85% snow, 8% debris and 7% ice-cemented permafrost fragments, and is evidenced by a thin residual deposit draping the valley sides, as most of this deposit melted out before any field control was undertaken. The growth of the lake level, along with the dam weight loss due to ablation, generated the hydrostatic instability that caused the floating of the central sector of this second dam and the violent evacuation of the water, similar to a jökulhlaup. This analysis explains the partial dam collapse, sudden water release and the preserved field evidence. This different interpretation suggests that the mitigation actions already taken can be improved and that monitoring systems are urgently needed. A rapid and professional assessment of any large-scale geohazard site would be the way to avoid interpretation discrepancies, and to guarantee that mitigation actions taken are adequate. Learning from this event may help decision makers to take better mitigation measures and potentially save lives. Full article

Producing ice using adsorption systems can represent a sustainable solution and meet the recent global environmental regulations as they use natural refrigerants and can be driven by solar energy. However, the beds used in these systems still have low thermal and adsorption characteristics. This study investigates numerically the use of an emerging aluminum foamed bed packed with advanced Maxsorb adsorbent in a two-bed adsorption system and reports cases of performance improvements compared to the classical finned-tube based system used to produce ice. A comprehensive 2-D transient pressure distribution model for the two beds was developed and validated. The model considers the temporal and spatial variations of the two beds’ parameters, while the effect of the thermal mass and heat transfer effectiveness of the condenser and evaporator components are imitated at the boundary conditions for bed openings using two zero-dimensional models. The results show the interrelated effects of varying the cycle times from 400 s to 1200 s with 2, 5, and 10 mm foam thicknesses/fin heights on the overall performance of both systems. The Al-foam based system demonstrated the performance superiority at a 2 mm foam thickness with maximum ice production of 49 kg_ice/kg_ads in 8 h, an increase of 26.6% over the counterpart finned-tube based system at a 400 s cycle time. The best COP of 0.366 was attained at a 5 mm foam thickness and 1200 s with an increase of 26.7%. The effective uptake of the Al-foam based system was reduced dramatically at a 10 mm foam thickness, which deteriorated the system performance. Full article

The potential impacts of sea level in the study region are presented using the Integrated Procedure for Estimate Sea Level Impacts (IPESLI), made up of Landsat images, official databases, and design software for geographic information systems. IPESLI is useful in areas with little georeferenced and validated information. The sea level projections are based on the climate projections, which incorporate the possible attenuation of the ice sheet near the upper end of Antarctica. Flood risk statistics were used to simulate the frequency of extreme flooding across the planet. The IPESLI was calibrated using seven field visits to compare the height values generated by the digital elevation model against the in situ data. The inundation maps generated in the study can be used to find the most vulnerable areas and initiate decision making for coastal adaptation. The IPESLI procedure has the potential to contribute to the formation of a communication bridge between climate change science and policy makers. The projection is profound for all scenarios, but it is particularly devastating for the Acapulco Diamante area if we start with the worst future climate scenario (SSP5-RCP8.5). Full article