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Abstract The accurate information of the thermal stresses and temperature in isotropic elastic solids is the key for many engineering applications. At present the classical linear coupled theory of thermoelasticity deduced with the assumptions of small temperature changes is widely used to solve the thermoelastic problems in engineering. In this paper, to describe the thermoelastic behavior in isotropic solids undergoing large temperature changes more accurately, the novel coupled models of thermoelasticity and the corresponding finite element models have been presented explicitly and validated by experimental measurement. The effect of large temperature changes on the solutions of thermoelastic problems is discussed. For the heat transfer process, if the isotropic elastic solids will expand when heated and contract when cooled and the condition d E E d T · σ i j E − δ i j 1 − 2 ν α 0 can be met in the context of small deformations, the effect of large temperature changes can be regarded as increasing the specific heat. The proposed models are applied to solve two thermoelastic problems. From the obtained numerical results, the effect of large temperature changes will increase with the amplitude of temperature change and may be considerably even when the temperature changes slowly.

Abstract Date biomass is a carbon-rich renewable resource that can be considered a potential carbon-rich substrate for energy generation over anaerobic digestion (AD). However, due to its complex nature, appropriate pretreatment is necessary to achieve a higher methane yield. Hence, the current study was envisioned to evaluate the influence of three different pretreatment strategies, namely acid, alkali, and hydrothermal pretreatment on biochemical methane potential (BMP) of seven diverse sorts of Algerian date biomass, namely Pedicels, Fibrilium, Petiole, Fruit bunch, Spath, Palm, and its mixture. Among all the pretreatment conditions, alkaline pretreatment highly influenced the lignin composition of date biomass and showed higher BMP. Among all sorts of biomass, higher BMP was detected through Palm as 295.9 mL CH4/g-TS, whereas the lowest BMP values were recorded with Petiole as 226.74 mL CH4/g-TS. Among all the experimental variations, ammonium pretreated Palm biomass documented the highest substrate conversion efficiency (63.80%), which correlates well with the observed higher BMP values. Nevertheless, there was a very marginal improvement in BMP detected in the case of other pretreatment strategies compared to alkaline pretreatment. This might be due to the efficacy of the applied pretreatment method on delignification of date biomass.

In the backdrop of COVID19 recovery, Pakistan is still struggling to cope with the economic challenges and disruptions caused in the energy supply chain. On one hand where COVID has brought serious socio-economic costs and prolonged delays, it has also provided opportunity for developing countries such as Pakistan to “build-forward-better” their economies in a more sustainable and climate friendly manner. This study particularly highlights the impact of COVID on energy supply and demand sectors of Pakistan, its near- and long-term impacts, and what policy interventions can be adopted to put Pakistan on-track to achieve its Nationally Determined Contributions (NDCs). The economic focus in on “Green Recovery” and what key interventions will foster a rapid transition towards decarbonization in Pakistan. Low Emission Analysis Platform (LEAP) model is used to provide energy sector outlook (2020-2040) of Pakistan under different scenario i.e., Pre COVID growth, Business-as-Usual, Slow Recovery, and Green Recovery from COVID. The results obtained from the model depicts that following a green recovery scenario, Pakistan can reduce around 10 Mtoe (9%) of its total energy use, 53 TWh of electricity, 19 Mt of emissions from demand sectors, and 11 Mt of emissions from the power sector by 2030. For total levelized cost of the power sector, the green recovery scenario represents a generation cost of $13 billion by 2030 which further highlights that energy efficiency could lead to cost savings of approximately $3 billion each year by 2030. Green recovery is however still a daunting task as it would require economic stimulus of $8 billion only to recover to its pre COVID scenario and total investments of $120 billion by 2030.

Exterior insulation finishing systems (EIFSs) can efficiently promote energy efficiency of buildings. In this study, an EIFS with high thermal efficiency is presented to improve the insulation behavior of building enclosure. Based on heat transfer analysis results, energy simulations of buildings with fire spread prevention structures were performed. Results revealed that heat flow through the wall increased by 10.3 % when using a metal rail to fix the insulation; in contrast, using non-combustible phenolic foam reduces heat flow by 37.4 %, satisfying the requirement for fire spread prevention structures. Additionally, the energy consumption decreased by 8.8 % when both mineral wool and phenolic foam were applied. Fire spread prevention structures are essential to improve the fire safety performance of buildings. This external insulation system efficiently promote energy saving in building; additionally, leveraging a phase change material to improve the thermal storage performance of the building can reduce energy consumption by up to 11.9 %.

Renewable energy has become more popular since it is cost-effective and more efficient than conventional energy sources. Biomass-based renewable energy is primarily used in emerging economies to ensure environmental sustainability. This study examines the asymmetric correlation between biomass energy consumption and CO2 emissions in the top-10 biomass energy consumer countries (Brazil, Canada, Thailand, China, Italy, India, Germany, USA, UK, and Japan). A new approach "Quantile-onQuantile (QQ)" is employed by utilizing the data from 1991 to 2018. Biomass energy consumption, with the exception of Thailand, significantly mitigates CO2 emissions at various quantiles in selected countries. As a robustness check, we used the quantile regression test, whose findings are consistent with the outcomes from the quantile-on-quantile method. However, the degree of asymmetry in the biomass energy-CO2 nexus varies by country, necessitating extra attention and government vigilance when developing biomass energy and environmental policies.

Reactive ion etching of silicon oxide and silicon nitride was conducted by the injection of nitrogen trifluoride (NF3) and nitrogen oxide trifluoride gas (F3NO). The etching process was studied using a residual gas analyzer (RGA) and optical emission spectroscopy (OES); this included confirming and comparing the characteristics of the F3NO plasma to that of the NF3 plasma by discharging and measuring the pure NF3 plasma and F3NO plasma. Furthermore, silicon oxide and silicon nitride etching were performed using a process gas (NF3, F3NO) and an argon mixture. The plasma etching process was similarly diagnosed by RGA and OES, and the etch rate was calculated by measuring the reflection. The etch rate of silicon oxide during F3NO/Ar plasma etching is approximately 94% of that for NF3/Ar plasma etching and the etch rate of silicon nitride is approximately 76% of that for NF3/Ar plasma etching under the same conditions. The RGA and OES measurements confirmed that more O+, NO+, and O2+ ions were generated in the F3NO plasma than in the NF3 plasma. This difference makes it possible to confirm the variation in etch rates between silicon oxide and silicon nitride.

Cette étude examine les caractéristiques des profils de vitesse, de champ thermique et d'entropie pour l'écoulement de nanofluides hybrides traversant une feuille d'amidonnage avec un rayonnement thermique. Les nanotubes de carbone (SWCNT et MWCNT) sont utilisés comme nanoparticules avec flux de chaleur Cattaneo-Christov (CC). L'éthylène glycol est utilisé comme fluide de base dans ce cas. Pour obtenir une solution améliorée, l'écoulement de fluide sur les propriétés géométriques est conçu en utilisant des PDE hautement non linéaires, et les équations gouvernantes doivent être converties en systèmes d'équations non similaires sans dimension en utilisant le schéma de Keller-box bien connu et très efficace dans le logiciel de calcul Matlab. La faisabilité pratique de ces solutions est déterminée par la plage des paramètres de contrôle. La distribution de vitesse diminue à mesure que l'estimation des paramètres magnétiques augmente, cependant, le champ de température et la production d'entropie augmentent à mesure que la fluctuation des paramètres magnétiques diminue. Au fur et à mesure que le paramètre de glissement augmente, le champ de vitesse diminue. Le champ thermique est amélioré pour augmenter le paramètre de rayonnement, et le profil d'entropie est renforcé pour augmenter les valeurs des paramètres de Brinkman. Les résultats de cette recherche pourraient avoir un impact significatif sur les industries où le refroidissement et le chauffage locaux par jets d'impact sont nécessaires dans les appareils électroniques, les dissipateurs thermiques, les technologies de séchage, etc. À la connaissance des auteurs, il s'agit du premier effort visant à utiliser un nanofluide hybride pour analyser la formation d'entropie due au flux magnétohydrodynamique sur une feuille d'amidonnage. Este estudio examina las características de los perfiles de velocidad, campo térmico y entropía para el flujo híbrido de nanofluidos que pasa a través de una lámina de almidón con radiación térmica. Los nanotubos de carbono (SWCNT y MWCNT) se utilizan como nanopartículas con flujo de calor Cattaneo-Christov (CC). El etilenglicol se utiliza como fluido base en este caso. Para lograr una solución mejorada, el flujo de fluido sobre las propiedades geométricas se diseña utilizando PDE altamente no lineales, y las ecuaciones gobernantes deben convertirse en sistemas de ecuaciones no similares adimensionales utilizando el conocido esquema de Keller-box altamente eficiente en el software computacional MATLAB. La viabilidad práctica de estas soluciones está determinada por el rango de los parámetros de control. La distribución de velocidad se reduce a medida que aumenta la estimación del parámetro magnético, sin embargo, el campo de temperatura y la producción de entropía aumentan a medida que la fluctuación del parámetro magnético se aclara. A medida que aumenta el parámetro de deslizamiento, el campo de velocidad disminuye. El campo térmico se mejora para aumentar el parámetro de radiación, y el perfil de entropía se aumenta para aumentar los valores de los parámetros de Brinkman. Los hallazgos de esta investigación podrían tener un impacto significativo en las industrias donde se necesita refrigeración local y calefacción a través de chorros de choque en dispositivos electrónicos, disipadores de calor, tecnologías de secado, etc. Según el conocimiento de los autores, este es el primer esfuerzo para emplear un nanofluido híbrido para analizar la formación de entropía debido al flujo magnetohidrodinámico sobre una lámina de almidón. This study examines the characteristics of the velocity, thermal field and entropy profiles for hybrid nanofluid flow passing through a starching sheet with thermal radiation. The carbon nanotube (SWCNT and MWCNT) are used as a nanoparticles with Cattaneo-Christov (CC) heat flux. Ethylene glycol is utilized as a base fluid in this case. To achieve an improved solution, the fluid flow over the geometric properties is designed using highly non-linear PDEs, and the governing equations must be converted into dimensionless non-similar equation systems using the highly efficient well-known Keller-box scheme in computational software MATLAB. The practical feasibility of these solutions is determined by the range of the controlling parameters. The velocity distribution reduces as the magnetic parameter estimate increases, however, the temperature field and entropy production increase as the magnetic parameter fluctuation esclates. As the slip parameter is increased, the velocity field diminish. The thermal field is enhanced for rising the radiation parameter, and the entropy profile is boosted for increasing Brinkman parameter values. The findings of this research might have a significant impact on industries where local cooling and heating via impingement jets are needed in electronic devices, heat sinks, drying technologies, and so on. To the best of the authors' knowledge, this is the first effort to employ a hybrid nanofluid to analyze entropy formation due to magnetohydrodynamics flow over a starching sheet. تبحث هذه الدراسة في خصائص ملامح السرعة والحقل الحراري والانتروبيا لتدفق السوائل النانوية الهجينة التي تمر عبر ورقة النشا مع الإشعاع الحراري. يتم استخدام الأنبوب النانوي الكربوني (SWCNT و MWCNT) كجسيمات نانوية مع تدفق حراري Cattaneo - Christov (CC). يستخدم جلايكول الإيثيلين كسائل أساسي في هذه الحالة. لتحقيق حل محسّن، تم تصميم تدفق المائع عبر الخصائص الهندسية باستخدام PDEs غير خطية للغاية، ويجب تحويل المعادلات الحاكمة إلى أنظمة معادلات غير متشابهة بلا أبعاد باستخدام مخطط Keller - box المعروف عالي الكفاءة في البرنامج الحاسوبي MATLAB. يتم تحديد الجدوى العملية لهذه الحلول من خلال نطاق معلمات التحكم. ينخفض توزيع السرعة مع زيادة تقدير المعلمة المغناطيسية، ومع ذلك، يزداد مجال درجة الحرارة وإنتاج الإنتروبيا مع تذبذب المعلمة المغناطيسية. مع زيادة معامل الانزلاق، يتناقص مجال السرعة. يتم تعزيز المجال الحراري لرفع معلمة الإشعاع، ويتم تعزيز ملف تعريف الإنتروبيا لزيادة قيم معلمة برينكمان. قد يكون لنتائج هذا البحث تأثير كبير على الصناعات التي تحتاج إلى التبريد والتدفئة المحليين عبر نفاثات الاصطدام في الأجهزة الإلكترونية وأحواض الحرارة وتقنيات التجفيف وما إلى ذلك. على حد علم المؤلفين، هذا هو أول جهد لتوظيف مائع نانوي هجين لتحليل تكوين الإنتروبيا بسبب تدفق الديناميكا المائية المغناطيسية على ورقة النشا.

Abstract Hydrogen is considered a potential game changer for world energy systems and a solution to climate change concerns, as it generates zero waste and it is suited for power generation and transportation. Despite its several advantages, there are significant technical challenges in deploying a stable hydrogen economy including improving its process efficiencies, lowering production costs, maintaining cost-effective transmission and distribution, and exploiting inexpensive and sustainable feedstocks. In this context, a detailed study was conducted to analyze the production sources, technologies, storage and transport systems, and global potential exportable feedstocks to produce hydrogen. A comprehensive analysis of current hydrogen production technologies with their energy efficiencies and hydrogen selling prices was reported in this study. Various hydrogen production technologies with their capital investments and CO2 emissions were also presented. Potential feedstocks for hydrogen production were identified and analyzed through a product space model, which characterizes a network of global exportable products based on their similarities and productive knowledge. It was established that the hydrogen production feedstocks and sources currently used are primarily available in six countries: the United States of America, France, Russia, Sweden, the Netherlands, and Spain. Broadly, the results revealed that the United States of America and Russia shared the highest hydrogen feedstock exports, indicating a higher probability of hydrogen production in these countries. Except for Russia, all the studied countries fell in the most desired quadrant, indicating that they can move in all product space directions to exploit unexplored hydrogen feedstocks for better sustainable economic growth.