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Biodiesel production processes using coconut oil containing a relatively high content of free fatty acids (4.5% w/v and higher) have been characterized using alkali, acid and enzymatic- based catalysts. The use of ethanol (molar ratio of 3:1 of ethanol:triglycerides) instead of methanol was evaluated in all processes. An alkali-based process resulted in rapid conversion of the triglycerides in the coconut oil to esters with an 80% conversion in 5-10 min. However pre-treatment with 0.7% H2SO4 v/v at 50oC for 3 h was required before alkali addition to avoid saponification of the free fatty acids. By comparison, a longer reaction time (50 h) was required for the acid process which also resulted in a lower conversion (67% at 50oC). The use of an acid overcomes the limitations of the alkali process of saponification when high FFA content oils are used, and gave a higher conversion 70% at 75oC after 300 min. By comparison use of an enzymatic (lipase) catalyst (1% w/v) at 50oC resulted in a conversion of 80% in 50 h. The enzyme based process under similar conditions was significantly improved by the use of high frequency sonication which reduced the reaction time to 3 h and achieved a 92% conversion of triglycerides to esters. To further improve the economics of the enzyme process, an initial study showed that the enzyme catalyst was able to be recycled with only a 20% decrease in conversion. The use of the glycerol by-product from the enzyme process as a carbon source for yeast growth resulted in improved kinetics to that for yeast growth on pure glycerol indicating that no inhibitory by-products were produced during the enzyme process. The overall economics of the process, and its sensitivity to key process variables was further analysed using a computer-based model of biodiesel production. It showed that an internal rate of return (IRR) of 30% for a commercial size plant of 4 million litre per annual.

AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

Abstract: After the implementation of a biofuel target in 2017, China, the second largest consumer of oil in the world, accelerated the development of lignocellulosic biomass technology to produce ethanol and minimized food security risks commonly associated with first generation biofuel production. In this study, Life Cycle Assessment (LCA) is used to investigate three new lignocellulosic biomass refinery systems based on corncob which co-produce ethanol with chemicals and energy. The bioethanol is used in E10 and E85 biofuel mixes and these are compared with a fossil gasoline reference system. Using 1 km distance driven by a compact size flexible fuel passenger vehicle as the functional unit and a exergy allocation approach to the raw material inputs and to the co-products in the simulated multifunctional biorefinery processes, the results indicate that regardless of the configuration of the ethanol-biorefinery, ethanol-blended fuels performed better than gasoline in terms of fossil fuels depletion (E10 6% lower; E85 64–70% lower), global warming potential (E10 1–10% lower; E85 5–113% lower) and human toxicity potential (E10 6–7% lower; E85 72–75% lower), but worst in terms of ozone layer depletion (E10 4.5–6.8 times higher; E85 51.9–78.2 times higher), acidification (E10 30–50% higher; E85 3.3–5.5 times higher) and eutrophication potential (E10 5.2–7.0 times higher; E85 42.4–64.0 times higher) than gasoline.

While different in emphasis, spirituality and sustainable development are intertwined concepts that cannot be meaningfully discussed in isolation from each other. This is especially pertinent in Pacific Island countries that are characterised by both high degrees of vulnerability to climate change and high degrees of religious engagement. There is a paucity of research that examines the relationship between spirituality and sustainable development in contemporary human development discourse. To address this gap in the literature, this research employs an inductive and exploratory methodological approach to the study of major development organisations in Australia. It investigates what significance contemporary NGOs ascribe to matters of spirituality in the design and implementation of their community aid and development programming in the Pacific and beyond. To achieve its goal, the study conducts a systematic term frequency analysis in the annual reports of government-funded and independently funded NGOs, both faith-based and secular. It extends previous research by focusing expressly on the intersectionality of sustainable development and spirituality as a fertile space for interdisciplinary inquiry. The findings link development policy and practice more closely to the needs and worldviews of Pacific peoples. A better understanding of the spirituality–sustainability nexus will enable more effective, sustainable, equitable, ethical, and culturally acceptable development programming. Crucially, integrated approaches promise to make ongoing community development programmes and adaptation responses to climate-driven environmental change more effective and sustainable. Finally, it is an important aim of this study to conceptualise various opportunities for future research, thus laying the foundation for an important emergent research agenda.

Abstract Herein, we report the dual functionality of a single n-type gallium nitride (n-GaN) layer as an electron transporter and transparent conductor, which has applications in reusable organic solar cells. After silicon doping with an optimized electron concentration, thin-film layer of GaN showed exceptional electrical properties including charge carrier mobility of 161 cm2 V−1s−1, electrical conductivity of 1.4ⅹ106 S cm−1, and sheet resistance of 11.1 Ω cm−2. Organic solar cells based on n-GaN exhibited power conversion efficiency comparable to those based on a conventional ITO/ZnO bilayered cathode. Furthermore, the n-GaN substrates exhibited reusability; due to excellent chemical stability of n-GaN, the reconstructed organic solar cells maintained their initial performance after the substrates were recycled. We suggest a new type of reusable n-GaN cathode layer featuring an integrated electron transporting layer and transparent electrode.

Abstract The study quantifies the benefits of expanding electric cooking in the residential sector in terms of kerosene and fuel wood saved from the perspective of long term optimal energy system development of Bhutan. It also investigates the reductions in the emissions of CO2 and the indoor pollutants, SO2 and NOx due to fuel switching in the cooking enduse. This study method is based on the first ever integrated long-term energy system modeling in Bhutan, which was undertaken previously by the lead author as a master thesis work but not published. The energy system model for Bhutan was developed under the MARKAL model framework. In Bhutan electricity generation is pre-dominantly hydropower based on run-of-the-river schemes. The model results indicate that a sectoral level policy to promote electric cooking reduces the use of kerosene by 1832 kiloliters and fuelwood by 55 kilotonnes per annum which consequently leads to reductions in the emissions of CO2, SO2 and NOx by 17%, 12% and 8% respectively. The electric cooking scenario also complements the vision of Bhutan to reduce deforestation and to remain carbon neutral for all times to come.

Les bâtiments représentent une quantité importante de consommation d'énergie, ce qui entraîne des problèmes d'émissions mondiales et de changement climatique. Ainsi, la gestion de l'énergie dans un bâtiment est de plus en plus explorée en raison de son potentiel important de réduction des dépenses globales d'électricité pour les consommateurs et d'atténuation des émissions de carbone. En ligne avec cela, un plus grand contrôle et une optimisation de la gestion de l'énergie intégrée aux ressources énergétiques renouvelables sont nécessaires pour améliorer l'efficacité énergétique des bâtiments tout en satisfaisant le confort de l'environnement intérieur. Même si des mesures sont prises pour réduire la consommation d'énergie dans les bâtiments avec plusieurs techniques d'optimisation et de contrôle, certains problèmes restent non résolus. Par conséquent, ce travail fournit un examen complet des méthodes de contrôle conventionnelles et intelligentes en mettant l'accent sur leur classification, leurs caractéristiques, leur configuration, leurs avantages et leurs inconvénients. Cet examen examine de manière critique les différents objectifs et contraintes d'optimisation en ce qui concerne la gestion du confort, la consommation d'énergie et la planification. En outre, la revue décrit les différentes approches méthodologiques des algorithmes d'optimisation utilisés dans la gestion de l'énergie des bâtiments. Les contributions du contrôleur et de l'optimisation dans la gestion de l'énergie des bâtiments avec la relation des objectifs de développement durable (ODD) sont expliquées rigoureusement. Des discussions sur les principaux défis des méthodes existantes sont présentées afin d'identifier les lacunes pour les recherches futures. L'examen fournit des orientations futures efficaces qui seraient bénéfiques pour les chercheurs et les industriels afin de concevoir un contrôleur optimisé efficacement pour la gestion de l'énergie du bâtiment en vue de cibler les ODD. Los edificios representan una cantidad significativa de consumo de energía que conduce a los problemas de las emisiones globales y el cambio climático. Por lo tanto, la gestión de la energía en un edificio se explora cada vez más debido a su importante potencial para reducir los gastos generales de electricidad para los consumidores y mitigar las emisiones de carbono. En línea con ello, se requiere un mayor control y optimización de la gestión energética integrada con los recursos energéticos renovables para mejorar la eficiencia energética del edificio a la vez que se satisface el confort del entorno interior. A pesar de que se están tomando medidas para reducir el consumo de energía en edificios con varias técnicas de optimización y control, algunos problemas siguen sin resolverse. Por lo tanto, este trabajo proporciona una revisión exhaustiva de los métodos de control convencionales e inteligentes con énfasis en su clasificación, características, configuración, beneficios e inconvenientes. Esta revisión investiga críticamente los diferentes objetivos y restricciones de optimización con respecto a la gestión del confort, el consumo de energía y la programación. Además, la revisión describe los diferentes enfoques metodológicos de los algoritmos de optimización utilizados en la gestión energética de los edificios. Se explican de forma rigurosa los aportes del controlador y la optimización en la gestión energética del edificio con la relación de los objetivos de desarrollo sostenible (ODS). Se presentan discusiones sobre los desafíos clave de los métodos existentes para identificar las brechas para futuras investigaciones. La revisión ofrece algunas direcciones futuras efectivas que serían beneficiosas para los investigadores e industriales para diseñar un controlador optimizado de manera eficiente para la gestión de la energía de los edificios hacia la consecución de los ODS. Buildings account for a significant amount of energy consumption leading to the issues of global emissions and climate change. Thus, energy management in a building is increasingly explored due to its significant potential in reducing the overall electricity expenses for the consumers and mitigating carbon emissions. In line with that, the greater control and optimization of energy management integrated with renewable energy resources is required to improve building energy efficiency while satisfying indoor environment comfort. Even though actions are being taken to reduce the energy consumption in buildings with several optimization and controller techniques, yet some issues remain unsolved. Therefore, this work provides a comprehensive review of the conventional and intelligent control methods with emphasis on their classification, features, configuration, benefits, and drawbacks. This review critically investigates the different optimization objectives and constraints with respect to comfort management, energy consumption, and scheduling. Furthermore, the review outlines the different methodological approaches to optimization algorithms used in building energy management. The contributions of controller and optimization in building energy management with the relation of sustainable development goals (SDGs) are explained rigorously. Discussions on the key challenges of the existing methods are presented to identify the gaps for future research. The review delivers some effective future directions that would be beneficial to the researchers and industrialists to design an efficiently optimized controller for building energy management toward targeting SDGs. تمثل المباني كمية كبيرة من استهلاك الطاقة مما يؤدي إلى قضايا الانبعاثات العالمية وتغير المناخ. وبالتالي، يتم استكشاف إدارة الطاقة في المبنى بشكل متزايد بسبب إمكاناته الكبيرة في تقليل نفقات الكهرباء الإجمالية للمستهلكين والتخفيف من انبعاثات الكربون. وتماشياً مع ذلك، يلزم زيادة التحكم في إدارة الطاقة المتكاملة مع موارد الطاقة المتجددة وتحسينها لتحسين كفاءة استخدام الطاقة في المباني مع إرضاء راحة البيئة الداخلية. على الرغم من اتخاذ إجراءات لتقليل استهلاك الطاقة في المباني باستخدام العديد من تقنيات التحسين والتحكم، إلا أن بعض المشكلات لا تزال دون حل. لذلك، يوفر هذا العمل مراجعة شاملة لأساليب التحكم التقليدية والذكية مع التركيز على تصنيفها وميزاتها وتكوينها وفوائدها وعيوبها. تبحث هذه المراجعة بشكل نقدي في أهداف وقيود التحسين المختلفة فيما يتعلق بإدارة الراحة واستهلاك الطاقة والجدولة. علاوة على ذلك، تحدد المراجعة الأساليب المنهجية المختلفة لخوارزميات التحسين المستخدمة في بناء إدارة الطاقة. يتم شرح مساهمات المراقب والتحسين في بناء إدارة الطاقة مع العلاقة بين أهداف التنمية المستدامة (SDGs) بدقة. يتم تقديم مناقشات حول التحديات الرئيسية للطرق الحالية لتحديد الثغرات للبحث في المستقبل. تقدم المراجعة بعض الاتجاهات المستقبلية الفعالة التي ستكون مفيدة للباحثين والصناعيين لتصميم وحدة تحكم محسنة بكفاءة لبناء إدارة الطاقة نحو استهداف أهداف التنمية المستدامة.

Metal use and modern society are intrinsically linked and it is no surprise that global processes of industrialization and urbanization have led to ever increasing amounts of metal use. In recent decades, global supply and demand networks for metals have become increasingly complex. Industrial Ecology research is well placed to unpack this complexity and to explore potential resource efficiencies for metals. This is especially important during the current period of rising ore prices. We examine patterns of supply and demand for iron ore and bauxite, and recent trends in resource productivity of these two important metal ores. We introduce a consumption perspective and compare the material footprint of metal ores to the GDP of countries to look at how much economic benefit countries achieve per unit of metal footprint. We find that for the past two decades global amounts of iron ore and bauxite extractions have risen faster than global GDP, that both supply and demand of iron ore and bauxite have been concentrated in a handful of countries and that resource productivity from a consumption perspective has fallen in developed nations, as well as globally. The research shows no saturation of metal ore consumption at any level of income. Policies will be required to enhance both the productivity of metal production and the economic productivity of consumption (GDP per metal footprint) through more efficient mining, product design, reuse and recycling.