Abstract: In view of the insufficient heating capacity of a supercritical 600 WM unit, it is necessary to determine whether the equipment of the extraction and return heat pipe system can operate normally after the transformation, so as to check the adaptability of the extraction and return heat pipe system equipment of the heating unit. Based on the actual situation and heat balance before and after the transformation of the heating system, this study selects the extracting steam and heat return pipe system of the heating units at all levels, and makes adaptive accounting from the design parameters of the pipeline, and the calculations of steam flow rates or pipe diameters of the pipeline, which provide scientific basis and evaluation for the feasibility of the retrofit scheme. PubDate: Tue, 16 Nov 2021 03:24:12 +000
Abstract: In Payment for Environmental Services (PES) systems, environmental service providers receive compensation for a conservationist action that implies the preservation of natural resources. The objective of this systematic mapping was to identify and discuss scientific articles that address the theme 'Payment for Environmental Services - PES for Waste Pickers Organizations', to understand the state of art of hiring these workers as environmental service providers. The study was developed using the method of systematic mapping of literature, from 2009 to 2019, considering qualitative and quantitative aspects. Results indicated that the countries that most investigate this theme are Brazil, China, India, and Indonesia. The articles portray the informal work of waste pickers, working conditions and the transition from informal systems to waste management in public services. The relationship between payment for environmental services and the work of waste pickers is not yet evident. Furthermore, research on PES and recycling are developed along distinct lines, without interdisciplinarity. However, PES shows itself as an important socio-environmental management tool that has the potential to solve relevant problems of recyclable waste management, because it presents congruent characteristics with the public procurement systems for waste pickers. PubDate: Mon, 15 Nov 2021 01:07:55 +000
Abstract: Bipolar plates play a major role in the overall performance of fuel cells, hence their proper design and optimization are essential. In this regard, pressure drop across bipolar plates has a major impact on the efficiency. Therefore, it is crucial to minimize the friction between the plate walls and the working fluid, with a proper flow configuration, to eliminate pressure drops. The study, involved the simulation of various modified pin-flow bipolar plate configurations where a comparative analysis was carried out. A parametric study was performed to optimize various designs and operating parameters such as fluid flow, velocity and pressure. Computational fluid dynamics (CFD) was employed for the numerical simulation to ensure the optimum uniformity of fluid distribution. Results showed that the pressure drop is proportional to the velocity magnitude in the laminar region. Moreover, the pressure drop was minimized by eliminating the sharp edges in the flow channels. PubDate: Fri, 22 Oct 2021 03:08:54 +000
Abstract: Latest innovations in Internet of Things (IoT) technologies as well as the new paradigms in Artificial Intelligence systems are opening up opportunities to create smart computing infrastructures for the Healthcare Facility Management. However, the current scenario of hospital buildings maintenance management is strongly characterized by slow, redundant, and not integrated processes, which lead to loss of money, resources, and time. On the other hand, lack of data and information in as-built digital models considerably limits the potential of Building Information Modelling in Facility Maintenance Management. Consequently, optimization of data collection process and management is required. In this light, this paper presents a review of embedding AI (Artificial Intelligence) in BIM-IoT integration for the process of healthcare Facility Maintenance Management (FMM) in order to conquer the current challenges. The first challenge in front of integrating IoT– BIM, is the lack of information; the second challenge is BIM’s sematic information that has not been able to display indoor conditions’ elements which should be reconsidered; and the third challenge is the data size which is stored in systems as well as the eligibility of individuals to apply the related data. Additionally, some emerging trends in IoT are reviewed such as the combination of Machine Learning and Artificial Intelligence in order to exploit their advantages and complement their limitations, which enable new promising IoT applications. PubDate: Mon, 06 Sep 2021 07:34:08 +000
Abstract: The energy and exergy analysis of an indirect-mode natural convection solar dryer for maize grain is presented. Two different sizes of maize grain bed depths of 0.04 m and 0.02 m translating into grain loads of 10 kg and 5 kg respectively, are used in the study to determine their effects on the collector energy and exergy efficiencies and the drying chamber exergy efficiency. Experiments were carried out using an indirect-mode laboratory solar dryer under a solar simulator with a radiation setting of 634.78 W/m2. The analysis gave average collector energy efficiencies of 33.3 % and 46.2 % for the 10 kg and 5 kg loads, respectively, which are higher than the collector exergy efficiencies of 2.4 % and 2.6 % for the 10 kg and 5 kg loads, respectively. The drying chamber exergy efficiencies are 45.2 % and 28.4 % for the 10 kg and 5 kg loads, respectively. In view of this, the 5 kg load is considered to be more efficient at extracting energy from the collector due to higher air flow resulting from its relatively thin grain bed depth of 0.02 m, but less efficient in utilising the extracted energy to evaporate moisture from the grain which has resulted in a lower drying chamber exergy efficiency. Further, the exergy loss in the drying chamber for the 5 kg load is higher than that in the 10 kg load as 72.3 % of the exergy entering the drying chamber is lost through emissions as well as destroyed through internal irreversibility compared to 57.0 % for the 10 kg load. PubDate: Thu, 15 Jul 2021 02:18:05 +000
Abstract: This paper examines how residential sector gas demand in gas exporting countries response to changes by taking into consideration the economic variables. For this purpose, the short and long-run price and income elasticities of residential sector gas demand in the GECF countries for 2000 and 2019 are measured. Using Cobb-Douglas functional form, this paper applies the bounds testing approach to co-integrate within the framework of ARDL (Autoregressive Distributed Lag). Findings of this research show that there is a significant long-run relationship in nine GECF countries, including Algeria, Egypt, Iran, Malaysia, Norway, Peru, Russia, Trinidad and Tobago and Venezuela, that use gas as a source of energy in their residential sector. On average, long-rung income elasticity for underlying countries is 2.65, while long-run price elasticity is negative and calculated at 0.79. This shows that in considered gas exporting countries, residential sector gas demand is very sensitive to income policies, while the price policies impact on demand is more limited. Furthermore, short-run income and price elasticities are estimated at 6.99 and -0.02 (near zero) respectively, which implies that natural gas is very inelastic to price, as a result,price policies are unable to make significant changes in demand over the short-term. Meanwhile, as expected short-run price elasticity is lower than long-run elasticities, indicating that gas exporting countries are more responsive to price in the long-term than in the short-term. Finally, it was found that most of the preferred models have empirical constancy over the sample period. PubDate: Thu, 15 Jul 2021 01:44:22 +000
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