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Fagorite, Victor Inumidun, Damian Ifeanyi Njoku, Henry Olumayowa Oluwasola, Samuel Okechukwu Onyekuru et Emeka Emmanuel Oguzie. « Review of Solar Energy Applications for Water Treatment ; a Global and African Perspective ». Geoinformatica Polonica 21 (30 décembre 2022) : 57–82. http://dx.doi.org/10.4467/21995923gp.22.005.17083.
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Solar energy is energy derived from the sun’s radiation. The sun’s energy can be exploited using a variety of technologies, including (a) photovoltaic (PV)/concentrator photovoltaics (CPV) systems that convert photons to electricity; and (b) solar thermal technologies that capture thermal energy from the sun’s radiation using solar collectors or concentrated solar power systems (CSP). Due to the quest for power supply from renewable, cheap, and non-gaseous emission sources coupled with the attempts to combat the shortage of potable water in rural areas, much research on the interface of solar energy power systems with water treatment plants has been reported. However, the greater part of the existing reports are based on theoretical modelling, with only minimal experimental, cost analysis, pilot projects and strategic studies. Also, even though solar-powered water treatment technologies are still in the early stages of research, and very rare studies based on real plants have been conducted, existing publications are mostly focused on single principles, making it impossible to assess and compare several technologies. Globally, this review has particularly highlighted the recent advances in the application of solar energy technologies in desalination and wastewater treatments. It likewise highlighted the key research findings and the critical gaps in the existing achievements. It further highlighted the attempts made on hybrid techniques with other renewable energy sources such as wind and geothermal energies which are paramount for scaling up and commercialization uses. However, the findings revealed that most of these studies were restricted to particular parts of the globe without candid evidence from the African perspective, especially Sub-Saharan Africa. Thus, due to the paucity of information concerning this topic within the region, there is a need for further studies on the application of solar energy for water treatment, especially on a pilot scale level for sustainable development. PRZEGLĄD ZASTOSOWAŃ ENERGII SŁONECZNEJ DO OCZYSZCZANIA ŚCIEKÓW; PERSPEKTYWA GLOBALNA I AFRYKAŃSKA Energia pochodząca z promieniowania słońca może być eksploatowana przy użyciu różnorodnych technologii, w tym (a) fotowoltaiki (PV)/skoncentrowanej fotowoltaiki (CPV), systemów, które przekształcają fotony w energię elektryczną; i (b) słoneczne technologie cieplne, które wychwytują energię cieplną z promieniowania słonecznego przy pomocy kolektorów słonecznych lub skoncentrowanych systemów energii słonecznej (CSP). Z powodu poszukiwań dostaw energii ze źródeł odnawialnych, tanich i nie emitujących zanieczyszczeń gazowych, a także wysiłków na rzecz walki z niedoborem wody pitnej w obszarach wiejskich, opublikowano wiele badań na temat systemów pozyskiwania energii słonecznej dla obsługi oczyszczalni ścieków. Jednakże większość istniejących opracowań oparta jest o modelowanie teoretyczne, jedynie z minimalną częścią eksperymentalną, analizą kosztów, projektami pilotażowymi i studiami strategicznymi. Co więcej, technologie oczyszczania wody zasilane energią słoneczną wciąż są na wczesnym etapie, a prace dotyczące badań w prawdziwych oczyszczalniach są rzadkie, publikacje w większości skupiają się na pojedynczych przypadkach, uniemożliwiając porównywanie kilku technologii wykorzystujących energię słoneczną do odsalania wody i oczyszczania ścieków. Wskazuje również kluczowe wyniki badań oraz istotne braki w istniejącym stanie zaawansowania. Ponadto przedstawia próby z technikami hybrydowymi, wykorzystującymi inne odnawialne źródła energii, takie jak wiatr i energia geotermalna, które są kluczowe w zwiększaniu skali produkcji i komercjalizacji. Jednakże wyniki badań wskazują, że większość prac ograniczona jest do innych kontynentów; brak jest jasnej afrykańskiej perspektywy, szczególnie dotyczącej Afryki subsaharyjskiej. Tak więc, z powodu skąpych informacji na ten temat, które dotyczą tego regionu, istnieje potrzeba dalszych badań nad zastosowaniem energii słonecznej do oczyszczania ścieków, szczególnie w skali pilotażowej, które przyczynią się do zrównoważonego rozwoju.
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Chen, Lihao, et Kunio Yoshikawa. « Bio-oil upgrading by cracking in two-stage heated reactors ». AIMS Energy 6, no 1 (2018) : 203–315. http://dx.doi.org/10.3934/energy.2018.1.203.
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Park, Sung-Ho, Won-Tae Kim et Ji-Hwan Jeong. « Analysis of Component Parts of OPR1000 Nuclear Power Plants Demanded at the Operation Stage ». Journal of Energy Engineering 30, no 2 (30 juin 2021) : 20–29. http://dx.doi.org/10.5855/energy.2021.30.2.020.
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Imran, Rasool M., et Kadhim Hamzah Chalok. « Innovative mode selective control and parameterization for charging Li-ion batteries in a PV system ». AIMS Energy 12, no 4 (2024) : 822–39. http://dx.doi.org/10.3934/energy.2024039.
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<p>Li-ion batteries can be charged with different techniques according to the charging time and required capacity usage. Most charging techniques face difficulties when implemented in PV systems due to the intermittent and unpredictable nature of the power supply. This paper addresses the issue of determining the appropriate charging technique for Li-ion batteries in a PV system. We have developed a mode-selective control approach that determines the optimal charging mode according to the given SOC and solar irradiation, aiming to maximize the utilization of the generated PV power. The developed control approach has been implemented using a dual-switched buck converter in the MATLAB/Simulink environment. The key control algorithm focused on regulating current, with different references being used based on the selected charging mode. Three references for charging current were set: the maximum current, the required current assigned based on the given SOC, and the pulsed current. The pulsed current reference was employed during a stage of the charging process to accelerate charging and prevent dissipation of PV power. Furthermore, a gain-scheduled controller with carefully picked control parameters was used to ensure stable operation across different modes. The results proved the effectiveness of the proposed control in reducing charging time and minimizing PV power dissipation without resorting to the use of harmful charging currents.</p>
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Zhao, Xianhui, Lin Wei et James Julson. « First stage of bio-jet fuel production : non-food sunflower oil extraction using cold press method ». AIMS Energy 2, no 2 (2014) : 193–209. http://dx.doi.org/10.3934/energy.2014.02.193.
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Tsai, Ming-Tang, et Chih-Jung Huang. « Integration of the radial basis functional network and sliding mode control for the sunshine radiation forecast ». AIMS Energy 12, no 1 (2023) : 31–44. http://dx.doi.org/10.3934/energy.2024002.
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<abstract> <p>In this paper, we propose a forecasting system of sunshine radiation for planners to quickly and accurately predict the output of solar power. The field data, including observation time, temperature, relational humidity, wind speed and global radiation, were collected, and the data clusters were embedded in the Excel Database. To improve the computational performance, the data selection technique was used in the stage of data cleaning, data integration and data reduction. Using the Integration of the Radial Basis Function Network (RBFN) and Sliding Mode Control (SMC), a Sliding Mode Radial Basis Function Network (SMRBFN) was proposed to solve this forecasting problem. Since the Sliding Mode Control has the design's sense of optimal parameters, three parameters in the SMRBFN were dynamically adjusted to promote the accurate and reliability of forecasting system. Linking the SMRBFN and Excel database, the learning stage and testing stage of SMRBFN retrieved the input data from Excel Database to perform and analyze the forecasting system. The proposed algorithm was tested on Kaohsiung district in summer and winter. The average prediction error of MAPE and RMSE obtained from the forecasting results are about 9% and 0.223, respectively. It can be proved that SMRBFN can efficiently forecast the sunshine radiation and accurately provide the output of solar power in an uncertainty environment.</p> </abstract>
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Tsuzuki, Yuto, Yutaro Akimoto et Keiichi Okajima. « Preventive control method for stable operation of proton exchange membrane fuel-cell stacks ». AIMS Energy 11, no 1 (2023) : 64–78. http://dx.doi.org/10.3934/energy.2023004.
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<abstract> <p>Flooding and dry-out are major drawback issues in proton exchange membrane fuel cells (PEMFC), which necessitate adequate prevention control techniques. In a fuel-cell stack, as flooding and dry-out occur on the inlet and outlet sides, respectively, both faults can exist simultaneously. Therefore, the timely detection of these two contradictory faults is crucial for implementing timely control measures. In this study, we propose a preventive control method that detects the fault signs early for more effective prevention. The proposed method uses a curve-fitting method, which uses overpotential as the control index. As the control index can be obtained by measuring the current, voltage, and temperature, the evaluation can be performed quickly, making it easy to implement in a PEMFC system. Under a single fault, the stack output power, hydrogen consumption, and power efficiency of the proposed preventive control method and the previous study on flooding were compared. The results showed that our preventive control method could detect flooding sooner and was superior in stack output power, hydrogen consumption, and power generation compared to the fault control method. Under conditions of mixed flooding and dry-out, both flooding and dry-out were detected using the overpotential as the control index. Thus, because the proposed method initiates control measures before the fault progresses, it is possible to ensure the continued stable operation of the fuel cells.</p> </abstract>
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Cheng, Shouyun, Lin Wei, Xianhui Zhao, Yinbin Huang, Douglas Raynie, Changling Qiu, John Kiratu et Yong Yu. « Directly catalytic upgrading bio-oil vapor produced by prairie cordgrass pyrolysis over Ni/HZSM-5 using a two stage reactor ». AIMS Energy 3, no 2 (2015) : 227–40. http://dx.doi.org/10.3934/energy.2015.2.227.
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Ferreira Costa, Levy, et René Pastor Torrico Bascopé. « Stand-alone Photovoltaic System With Three Energy Processing Stages ». Eletrônica de Potência 16, no 4 (1 novembre 2011) : 348–56. http://dx.doi.org/10.18618/rep.20114.348356.
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Harapan, M.T., Andi. « KAJIAN PENGARUH DAUR HIDUP BANGUNAN TERHADAP MENINGKATNYA PEMAKAIAN ENERGI DI DALAM BANGUNAN ». Jurnal Arsitektur ARCADE 5, no 2 (2 août 2021) : 135. http://dx.doi.org/10.31848/arcade.v5i2.758.
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Abstract: The increased of energy used on building operational is impacted by many factors, specially impacted by building delivering process. Delivering process is starting from design stage, construction stage until operational (occupacion) stage. If one of this staging is worst, would be affecting to the other staging (bad or good). Design stage is the crutial process on building delivering process, because on this stage the building criterias are setted and inputted to the drawing and specification documents. One of the example is energy used of the building, which should be setted on the design process and applied on the drawing and construction processes. This research is conducted with literature study and coparing with some datas about energy used of building in general about energy used of buildings.Abstrak: Meningkatnya pemakaian energi pada tahap operasional (pemakaian) tidak terlepas dari pengaruh tahap-tahap sebelumnya dari bangunan tersebut. Tahap desain, tahap konstruksi, dan tahap operasional dan maintenance merupakan suatu rangkaian kegiatan yang saling mempengaruhi yang sering diistilahkan sebagai daur hidup bangunan. Jika satu tahapan buruk maka akan memberikan dampak bagi tahapan berikutnya. Salah satu dampak negatif dari tidak baiknya daur hidup bangunan adalah meningkatnya pemakaian energi, yang dapat disebabkan oleh tahap desain yang tidak mempertimbangkan desain hemat energi, atau tahap konstruksi yang tidak baik sehingga menyebabkan pemakaian energi meningkat. Makalah ini merupakan studi kajian pustaka dari berbagai sumber terkait berbagai faktor yang mempengaruhi meningkatnya pemakaian energi pada tahap operasional di dalam bangunan yang dikaitkan dengan daur hidup bangunan.
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Nisha K.C.R, Nisha K. C. R., et T. N. Basavaraj T. N. Basavaraj. « Three Stage Cascaded Quasi-Z-Source Inverter System for Renewable Energy Applications ». Indian Journal of Applied Research 3, no 5 (1 octobre 2011) : 269–73. http://dx.doi.org/10.15373/2249555x/may2013/81.
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Al-Abdali, Akthem Mohi, et Handri Ammari. « Thermal energy storage using phase-change material in evacuated-tubes solar collector ». AIMS Energy 10, no 3 (2022) : 486–505. http://dx.doi.org/10.3934/energy.2022024.
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<abstract> <p>The use of phase change materials in solar thermal collectors improves their thermal performance significantly. In this paper, a comparative study is conducted systematically between two solar receivers. The first receiver contains paraffin wax, while the other does not. The goal was to find out to which degree paraffin wax can enhance the energy storage and thermal efficiency of evacuated tubes solar collectors. Measurements of water temperature and solar radiation were recorded on a few days during August of 2021. The experimental analysis depended on two stages. The first stage had a flow rate of 7 L/hr, and the second stage had no flow rate. A flow rate of 7 L/hr gave an efficiency of 47.7% of the first receiver with phase-change material, while the second conventional receiver had an efficiency rate of 40.6%. The thermal efficiency of the first receiver during the day at which no flow rate was applied was 41.6%, while the second one had an efficiency rate of 35.2%. The study's significant results indicated that using paraffin wax in solar evacuated tube water-in-glass thermal collectors can enhance their thermal energy storage by about 8.6% and efficiency by about 7%. Moreover, the results revealed that the solar thermal collector containing paraffin wax had an annual cost of 211 USD/year. At the same time, the receiver's yearly fuel cost was 45 USD. Compared to an electrical geyser, the annual cost reached 327 USD, with an annual fuel cost equaled 269 USD. The first receiver's payback period was 5.35 years.</p> </abstract>
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Jarid, Saad, et Manohar Das. « An Electro-Thermal Model based fast optimal charging strategy for Li-ion batteries ». AIMS Energy 9, no 5 (2021) : 915–33. http://dx.doi.org/10.3934/energy.2021043.
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<abstract> <p>This paper utilizes an integrated electro-thermal model of a lithium-ion battery to search for an optimal multistage constant current charge pattern that will minimize the total charging time of the battery, while restricting its temperature rise in each stage within safe limits. The model consists of two interlinked components, an electrical equivalent circuit model to continuously predict the battery's terminal voltage and a thermal model to continuously predict its temperature rise as charging progresses. The proposed optimization algorithm is based on a novel stepwise single-variable search technique that is very easy to implement and converges quickly. The results of our extensive simulation studies clearly indicate that the proposed charging strategy offers a fast, safe and easy-to-implement alternative to many of the existing computationally intensive optimal charging strategies.</p> </abstract>
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Živanović, Srđan, Veselinka Kulić, Natalija Hadživuković, Jelena Pavlović et Sandra Matović. « Dietary habits and nutritional status of adolescents ». Биомедицинска истраживања 11, no 2 (2020) : 167–75. http://dx.doi.org/10.5937/bii2002167z.
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The concept of proper nutrition implies meeting the needs of the body concerning daily energy intake and a sufficient amount of nutrients and protective substances necessary to maintain the physiological functions of the body and its health. Nutrients are divided into macronutrients (proteins, carbohydrates and fats) and micronutrients (vitamins and minerals). Accelerated growth and development during adolescence increase nutrient requirements. Therefore, energy and nutrition requirements must meet the needs of adolescents. During their growth and development, there is an increased need for vitamins and minerals, especially for calcium, iron, zinc and vitamin D. During intensive growth, adolescents require more vitamins, especially B-complex vitamins and vitamin C, the intake of calcium and phosphorus is necessary as well, and the insufficient needs for proteins affect the development of muscles and energy levels. Proper nutrition and eating habits during the period of growth are of the utmost importance for the appropriate physical, psychosocial and cognitive growth and development of a child. Eating disorders usually occur as a result of low or high energy intake, and the most common types of these disorders are anemia, anorexia and bulimia, obesity and comorbidities, and poor eating habits. When it comes to the implementation of various programs concerning the prevention of bad eating habits and eating disorders, the school management, expert teams and student parents should bear the overall responsibility. Once or twice a year, preventive check-ups and BMI measurements are recommended to identify eating disorders.
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Majdi Nasab, Navid, Jeff Kilby et Leila Bakhtiaryfard. « Integration of wind and tidal turbines using spar buoy floating foundations ». AIMS Energy 10, no 6 (2022) : 1165–89. http://dx.doi.org/10.3934/energy.2022055.
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<abstract> <p>Floating platforms are complex structures used in deep water and high wind speeds. However, a methodology should be defined to have a stable offshore structure and not fail dynamically in severe environmental conditions. This paper aims to provide a method for estimating failure load or ultimate load on the anchors of floating systems in integrating wind and tidal turbines in New Zealand. Using either wind or tidal turbines in areas with harsh water currents is not cost-effective. Also, tidal energy, as a predictable source of energy, can be an alternative for wind energy when cut-in speed is not enough to generate wind power. The most expensive component after the turbine is the foundation. Using the same foundation for wind and tidal turbines may reduce the cost of electricity. Different environment scenarios as load cases have been set up to test the proposed system's performance, capacity and efficiency. Available tidal records from the national institute of Water and Atmospheric Research (NIWA) have been used to find the region suitable for offshore energy generation and to conduct simulation model runs. Based on the scenarios, Terawhiti in Cook Strait with 110 m water height was found as the optimized site. It can be seen that the proposed floating hybrid system is stable in the presence of severe environmental conditions of wind and wave loadings in Cook Strait and gives a procedure for sizing suction caisson anchors.</p> </abstract>
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CHEN, Ching-Feng. « Offshore floating photovoltaic system energy returns assessment—A life cycle energy analysis-based perspective ». AIMS Energy 11, no 3 (2023) : 540–54. http://dx.doi.org/10.3934/energy.2023028.
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<abstract> <p>Researchers have long regarded photovoltaics (PV) as a poor energy return (ER) compared to fossil fuels. Although the latter's energy-return-on-investment (EROI), like oil, coal, and gas, are above 25:1 at the primary, they are about 6:1 at the final stage. Following the technology creation, it is essential to investigate whether the solar module technology innovation affects the ER. Much literature delivers the ERs of fossil fuels and PV. However, it does not address the life cycle analysis or life cycle energy analysis (LCEA) assessments. This paper, employing time-series and LCEA analyses, performs an ER evaluation of the 181-MWp global most extensive offshore floating PV (OFPV) in a 30-year life cycle at Changhua Coastal Industrial Park, Taiwan. The results show that the energy payback time (EPBT) is about one year. The EROI is about 29.8, which is superior or complies with the upper limits of previous studies under the same insolation. The approach proposed in this study should help future PV stations' ER analysis and clarify whether the innovation benefits from improving the system's performance. The results also assist in investors' decision-making regarding deploying PV projects in the future.</p> </abstract>
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Bertoncini, Martina, Adele Boggio, Federico Dell'Anna, Cristina Becchio et Marta Bottero. « An application of the PROMETHEE II method for the comparison of energy requalification strategies to design Post-Carbon Cities ». AIMS Energy 10, no 4 (2022) : 553–81. http://dx.doi.org/10.3934/energy.2022028.
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<abstract> <p>A resilient, diversified, and efficient energy system, comprising multiple energy carriers and high-efficiency infrastructure, is the way to decarbonise the European economy in line with the Paris Agreement, the UN 2030 Agenda for Sustainable Development, and the various recovery plans after the COVID-19 pandemic period. To achieve these goals, a key role is played by the private construction sector, which can reduce economic and environmental impacts and accelerate the green transition. Nevertheless, while traditionally decision-making problems in large urban transformations were supported by economic assessment based on Life Cycle Thinking and Cost-Benefit Analysis (CBA) approaches, these are now obsolete. Indeed, the sustainable neighbourhood paradigm requires the assessment of different aspects, considering both economic and extra-economic criteria, as well as different points of view, involving all stakeholders. In this context, the paper proposes a multi-stage assessment procedure that first investigates the energy performance, through a dynamic simulation model, and then the socio-economic performance of regeneration operations at the neighbourhood scale, through a Multi-Criteria Decision Analysis (MCDA). The model based on the proposed Preference Ranking Organisation Method for Enrichment Evaluations II (PROMETHEE II) aims to support local decision makers (DMs) in choosing which retrofit operations to implement and finance. The methodology was applied to a real-world case study in Turin (Italy), where various sustainable measures were ranked using multiple criteria to determine the best transformation scenario.</p> </abstract>
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Ortiz, Daniel J., et Diana J. Silva. « Consumo calórico de la dieta y requerimiento energético del personal militar en la etapa de reclutamiento, Chorrillos – 2022 ». Revista de Investigaciones de la Universidad Le Cordon Bleu 11, no 1 (janvier 2024) : 72–81. http://dx.doi.org/10.36955/riulcb.2024v11n1.007.
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El ejército del Perú es una institución castrense cuyo objetivo es controlar, vigilar, defender el territorio nacional y, de igual manera, participar en el desarrollo económico y social. Por consiguiente, los militares requieren una dieta adecuada para realizar estas vitales actividades. El objetivo de la investigación fue determinar la relación entre el consumo calórico de la dieta y el requerimiento energético del personal militar en su etapa de reclutamiento en Lima. Se cuenta con una muestra de 80 soldados en su etapa de reclutamiento de la compañía de construcción y vivienda N° 512 del Ejercito del Perú ubicada en Chorrillos, Lima. El 100 % de la muestra evaluada fue de sexo masculino y tienen una edad entre 18 a 30 años. El 95 % de la muestra tiene un consumo calórico alto (3 400 kcal a 2 900 kcal). El 100 % de la muestra presentó un gasto energético total (GET) promedio en el rango de (2 756,92 kcal a 2 928,2 kcal). Con relación al GET de la ecuación predictiva de Harris Benedict presentó el 50% un gasto energético alto (3 400 kcal a 2 900 kcal), con respecto a Miffling 85 % un gasto energético medio (2 899 kcal a 2 400 kcal) y con Cunningham un gasto energético medio (2 899 kcal a 2 400 kcal), presentando en todos estos un nivel de significancia (p<0,05) realizado por la prueba de chi cuadrado para ambas variables evaluadas. Se concluye que el consumo energético total presenta una relación con las tres fórmulas de ecuaciones predictivas, pero en el caso de HB sobreestima el GET. Mientras que para este grupo etario se recomendaría las fórmulas de Miffling y Cunningham para su estimación del gasto energético total (GET).
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Ramdhani, Rizky, Oleh Oleh et Aripin Aripin. « Pengujian Lapangan Bilah Airfoil Naca 5415 Dengan Turbin Angin The Sky Dancer 500 Watt ». Jurnal METTEK 8, no 1 (26 juillet 2022) : 9. http://dx.doi.org/10.24843/mettek.2022.v08.i01.p02.
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Energi merupakan sektor primer untuk kebutuhan hidup manusia, namun ironi negeri ini sektor energi masih dipasok oleh waste energy, dimana negeri-negeri tetangga sudah mulai memanfaatkan green energy. Indonesia dilimpahkan sumber daya energi baru-terbarukan sangat berlimpah, mulai dari panas matahari, panas bumi, angin, air, gelombang laut. Namun, kita belum mampu untuk memaksimalkan potensi yang diberikan. Contohnya, kecepatan rata-rata angin di Indonesia berkisar 2 m/s sampai dengan 11 m/s. Masuk dalam kecepatan angin rendah. Hampir mustahil memanfaatkan energi angin ini untuk skala besar. Akan tetapi, potensi angin ini tersedia hampir sepanjang tahun, maka dari itu, pengembangan teknologi turbin angin ini memungkinkan untuk skala mikro. Terdapat berbagai opsi untuk memaksimalkan energi angin dalam kecepatan rendah. Ada banyak opsi untuk menggunakan airfoil, parameter yang dicari adalah nilai Cl/Cd yang tinggi untuk mengekstrak energi angin pada kecepatan 2 m/s sampai 11 m/s. Pada penelitian ini dilakukan 3 tahapan, tahapan pertama perhitungan untuk menentukan jari-jari, chord, dan twist pada bilah. Tahapan kedua menggunakan bantuan software Q-blade untuk mengetahui Coefficient Performance dari airfoil yang digunakan dan 3D CAD Modelling. Tahapan ketiga yaitu proses manufaktur dan pengujian lapangan. Berdasarkan hasil perancangan, bilah yang dipilih adalah airfoil NACA tipe 5415 jenis taperless dengan jari-jari 0.875 m.
Energy is the primary sector for the needs of human life, but the irony of this country is that the energy sector is still supplied by waste energy, where neighboring countries have started to use green energy. Indonesia is bestowed with abundant new-renewable energy resources, ranging from solar heat, geothermal, wind, water, ocean waves. However, we have not been able to maximize the potential given. For example, the average wind speed in Indonesia ranges from 2 m/s to 11 m/s. Enter in low wind speed. It is almost impossible to harness this wind energy on a large scale. However, this wind potential is available almost all year round, therefore, the development of this wind turbine technology allows for micro-scale. There are various options for maximizing wind energy at low speeds. There are many options for using airfoils, the parameter to look for is a high Cl/Cd value to extract wind energy at speeds of 2 m/s to 11 m/s. In this study, 3 stages were carried out, the first stage was the calculation to determine the radius, chord, and twist on the blade. The second stage uses the help of Q-blade software to find out the Coefficient Performance of the airfoil used and 3D CAD Modeling. The third stage is the manufacturing process and field testing.
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Dewi, Marmelia P., Andri D. Setiawan, Yusuf Latief et Widodo Wahyu Purwanto. « Investment decisions under uncertainties in geothermal power generation ». AIMS Energy 10, no 4 (2022) : 844–57. http://dx.doi.org/10.3934/energy.2022038.
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<abstract> <p>Geothermal energy is one of the strategies employed by the Indonesian government to meet rising electricity demand. Developing geothermal energy is often characterized by uncertainties and requires sequential decision-making which is divided into four development phases: 1) identification, 2) exploration, 3) exploitation, and 4) engineering, procurement, construction, and commissioning (EPPC) before it can be commercialized. Traditional valuation techniques often produce a negative net present value (NPV), suggesting decision to reject the project's investment plan. This paper investigates the economic viability of a geothermal power generation project using both NPV and real options analysis (ROA). Costs and uncertainties associated with the various development phases as well as the investment structure of geothermal projects are studied. We develop a framework for assessing the impact of four uncertainties using a binomial lattice: capacity factor, electricity price, make-up well-drilling costs, and operation and maintenance (O&M) costs. Secondary data from an Indonesian context geothermal power plant was used. Positive option values were found for the lattice approach compared to negative values found for the common NPV calculation. The result of this study showed the successful outcome of the exploration stage is very critical to determining the continuation of the project. The framework supports decision-makers in evaluating the impact of geothermal power generation projects in the face of uncertainty by providing a rigorous analysis. The movement of the underlying asset's value in the whole project's lifetime will assist the management in deciding on whether to exit or continue.</p> </abstract>
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EISENBRAND, FRIEDRICH, STEFAN FUNKE, ANDREAS KARRENBAUER et DOMAGOJ MATIJEVIC. « ENERGY-AWARE STAGE ILLUMINATION ». International Journal of Computational Geometry & ; Applications 18, no 01n02 (avril 2008) : 107–29. http://dx.doi.org/10.1142/s0218195908002556.
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Consider the following illumination problem: given a stage represented by a line segment L and a set of light sources represented by a set of points S in the plane, assign powers to the light sources such that every point on the stage receives a sufficient amount – e.g. one unit – of light while minimizing the overall power consumption. Under the assumption that the amount of light arriving from a fixed light source decreases rapidly with the distance from the light source, this becomes an interesting optimization problem. We propose to reconsider the classical illumination problems as known from computational geometry literature under this light attenuation model. This paper examines the simple problem introduced above and presents different solutions, based on convex optimization, discretization and linear programming, as well as a purely combinatorial approximation algorithm. Some experimental results are also provided.
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Babqi, Abdulrahman J., NasimUllah, Ahmed Althobaiti, Hend I. Alkhammash et Asier Ibeas. « Current model predictive fault-tolerant control for grid-connected photovoltaic system ». AIMS Energy 10, no 2 (2022) : 273–91. http://dx.doi.org/10.3934/energy.2022015.
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<abstract><p>This paper investigates the performance of the current model predictive control (CMPC) for controlling a two-stage transformerless grid-connected photovoltaic (PV) system under grid fault conditions. A maximum power point tracking (MPPT) controller was used to extract the maximum power of the PV panel. To stabilize the DC link and generate the reference current values, a proportional-integral (PI) controller was used. The CMPC strategy was implemented to control the output current of the inverter that connects the PV system to the utility grid. The system and control strategy were simulated via a MATLAB/Simulink environment. The performance of the proposed control strategy was investigated under fault conditions between the three-phase two-level inverter and the grid. Moreover, to validate the capability of the CMPC, comparative case studies were conducted between CMPC, PI, and sliding mode control (SMC) under grid fault. Case studies' results showed that under grid fault, CMPC did not introduce any overshoot or undershoot in the PV output DC current and power. However, PI and SMC produced undershoots of almost 15 kW for the output power and 45 A for the output current. Under the fault conditions, the active output power and three-phase current recovery time of the inverter was 50 ms using CMPC, compared to PI and SMC with recovery times of 80 ms and 60 ms, respectively. Moreover, a voltage dip of 75 V at the DC link voltage was recorded with CMPC under faulty conditions, while the voltage dips for PI and SMC were around 180 V.</p></abstract>
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Elweddad, Mohamed, Muhammet Güneşer et Ziyodulla Yusupov. « Designing an energy management system for household consumptions with an off-grid hybrid power system ». AIMS Energy 10, no 4 (2022) : 801–30. http://dx.doi.org/10.3934/energy.2022036.
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<abstract> <p>This paper analyzes the effect of meteorological variables such as solar irradiance and ambient temperature in addition to cultural factors such as consumer behavior levels on energy consumption in buildings. Reducing demand peaks to achieve a stable daily load and hence lowering electricity bills is the goal of this work. Renewable generation sources, including wind and Photovoltaics systems (PV) as well as battery storage are integrated to supply the managed home load. The simulation model was conducted using Matlab R2019b on a personal laptop with an Intel Core i7 with 16 GB memory. The model considered two seasonal scenarios (summer and winter) to account for the variable available energy sources and end-user electric demand which is classified into three demand periods, peak-demand, mid-demand, and low-demand, to evaluate the modeled supply-demand management strategy. The obtained results showed that the surrounding temperature and the number of family members significantly impact the rate of electricity consumption. The study was designed to optimize and manage electricity consumption in a building fed by a standalone hybrid energy system.</p> </abstract>
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Daniel, Mburamatare, William K. Gboney, Hakizimana Jean de Dieu, Akumuntu Joseph et Fidele Mutemberezi. « Empirical assessment of drivers of electricity prices in East Africa : Panel data experience of Rwanda, Uganda, Tanzania, Burundi, and Kenya ». AIMS Energy 11, no 1 (2023) : 1–30. http://dx.doi.org/10.3934/energy.2023001.
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<abstract> <p>Sustainable electricity supply plays a key role in economic development. Cost recovery, profitability and affordability of electricity through power tariff regulation, have become a subject of conflict between private providers and regulators. Consequently, regulators need to balance the interests of all stakeholders. The objective of this study, is to measure to which extent, Electricity Net Consumption (EC), Electricity Net Generation (EG), electricity transmission and distribution losses (Losses), International Average Crude oil prices (FP), Consumer Price Index (CPI), Industry Value Added (IVA) could influence the Average Electricity Prices (EP) in East Africa, especially in Rwanda, Uganda, Tanzania, Burundi, and Kenya. The data are from World Bank Indicators and cover the period from 2000 to 2019. This study adopts a three-stage approach, consisting of panel unit root tests, panel cointegration tests and estimating the long run cointegration relationship of the variables in a panel context. We applied four different panel unit root tests including ADF-Fisher Chi-square, Levin, Lin and Chu (LLC); PP-Fisher Chi-square, and Im, Pesaran, and Shin, (IPS). The results reveal that the variables are non-stationary at "level", stationary at first-differences and integrated with order one denoted as I(1). The Pedroni, Kao and Johansen Fisher co-integration tests were performed. This study uses full modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DOLS) to estimate the long run relationship among the variables. We find that the increase in EG, FP, and CPI increase the Average Electricity Prices (EP); while the increase in Losses, EC, and IVA decreases EP. Therefore, we recommend the promotion of long-term investment policies in renewable sources and efficient policies to reduce technical and commercial losses. In addition, this study suggests that appropriate policies related to subsidized electricity prices would, however, prevent adverse effects related to inefficient over-consumption of electricity.</p> </abstract>
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Almihat, Mohamed G. Moh. « An overview of AC and DC microgrid energy management systems ». AIMS Energy 11, no 6 (2023) : 1031–69. http://dx.doi.org/10.3934/energy.2023049.
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<abstract> <p>In 2022, the global electricity consumption was 4,027 billion kWh, steadily increasing over the previous fifty years. Microgrids are required to integrate distributed energy sources (DES) into the utility power grid. They support renewable and nonrenewable distributed generation technologies and provide alternating current (AC) and direct current (DC) power through separate power connections. This paper presents a unified energy management system (EMS) paradigm with protection and control mechanisms, reactive power compensation, and frequency regulation for AC/DC microgrids. Microgrids link local loads to geographically dispersed power sources, allowing them to operate with or without the utility grid. Between 2021 and 2028, the expansion of the world's leading manufacturers will be driven by their commitment to technological advancements, infrastructure improvements, and a stable and secure global power supply. This article discusses iterative, linear, mixed integer linear, stochastic, and predictive microgrid EMS programming techniques. Iterative algorithms minimize the footprints of standalone systems, whereas linear programming optimizes energy management in freestanding hybrid systems with photovoltaic (PV). Mixed-integers linear programming (MILP) is useful for energy management modeling. Management of microgrid energy employs stochastic and robust optimization. Control and predictive modeling (MPC) generates energy management plans for microgrids. Future microgrids may use several AC/DC voltage standards to reduce power conversion stages and improve efficiency. Research into EMS interaction may be intriguing.</p> </abstract>
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Siregar, Heny Mahrani Rizkiyah, Rita Khathir et Kiman Siregar. « Life Cycle Inventory Mass Balance dan Energy Balance pada Proses Produksi CPO di PTPN IV PKS Bah Jambi Sumatera Utara ». Jurnal Ilmiah Mahasiswa Pertanian 7, no 2 (1 mai 2022) : 563–71. http://dx.doi.org/10.17969/jimfp.v7i2.19988.
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Abstrak. Indonesia merupakan produsen minyak sawit terbesar di dunia berperan penting dalam kegiatan ekonomi karena dapat menghasilkan minyak nabati dalam jumlah besar yang dibutuhkan oleh sektor industri sawit. Industri merupakan salah satu pengguna energi yang cukup besar. Dalam pelaksanaan proses produksi, industri menggunakan berbagai macam sumber energi baik yang berasal dari bahan bakar maupun yang berasal dari listrik. Pada proses pengolahan CPO (crude palm oil), terjadi beberapa tahapan proses yang memerlukan masukan-masukan material dan energi. Penelitian ini dilakukan di Pabrik Kelapa Sawit (PKS) Bah Jambi di Sumatera Utara. Hasil penelitian bahwa perusahaan menggunakan 4 sumber energi yaitu energi listrik, energi uap, energi BBM solar, dan energi biomassa. Rendemen hasil analisis sebesar 22,7% lebih kecil dari informasi rendemen perusahaan sebesar 24%. Pada tahapan pengolahan TBS menjadi CPO, sumber utama energi adalah energi uap sebesar 97,09%, di mana unit proses yang paling banyak mengonsumsi energi adalah unit proses pengempaan sebesar 30,85% dan unit penerimaan buah sebesar 25,32%. Sedangkan pada sarana pendukung, sumber energi utama juga energi uap sebesar 69,85%, di mana energi terbesar dibutuhkan untuk pengoperasian boiler sebesar 97,17%. Secara total, input energi berasal dari pembakaran biomassa sebesar 75%, energi uap 23%, energi BBM solar dan energi listrik sebesar 1%. Adapun efesiensi riil penggunaan boiler adalah 31,53%, efesiensi turbin dan generator dalam menghasilkan energi listrik 2,64%, dan efesiensi total penggunaan listrik sebesar 98,65%. Strategi peningkatan efisiensi ada beberapa cara yaitu pemanfaatan bahan bakar pada stasiun boiler dan pemanfaatan produksi limbah cair.Life Cycle Inventory Mass Balance And Energy Balance In CPO Production Process In PTPN IV PKS Bah Jambi North SumateraAbstract. Indonesia is the world's largest producer of palm oil and plays an important role in economic activity because it can produce large amounts of vegetable oil needed by the palm industry sector. Industry is one of the largest energy users. In carrying out the production process, the industry uses various sources of energy, both from fuel and from electricity. In the CPO processing, there are several process stages that require material and energy inputs. This research was conducted at the Bah Jambi Palm Oil Mill (PKS) in North Sumatra. The results showed that the company uses 4 energy sources, namely electrical energy, steam energy, diesel fuel energy, and biomass energy. The yield of the analysis results is 22.7% smaller than the company's yield information of 24%. At the processing stage of FFB into CPO, the main source of energy is steam energy of 97.09%, where the processing unit that consumes the most energy is the pressing process unit at 30.85% and the fruit receiving unit at 25.32%. While for supporting facilities, the main energy source is also steam energy of 69.85%, where the largest energy required for boiler operation is 97.17%. In total, energy input comes from biomass burning by 75%, steam energy 23%, diesel fuel energy and electricity energy by 1%. The real efficiency of the use of boilers is 31.53%, the efficiency of turbines and generators in generating electrical energy is 2.64%, and the total efficiency of electricity use is 98.65%. There are several strategies to increase efficiency, namely the use of fuel at the boiler station and the use of liquid waste production.
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Saligkaras, Dimitrios, et Vasileios E. Papageorgiou. « On the detection of patterns in electricity prices across European countries : An unsupervised machine learning approach ». AIMS Energy 10, no 6 (2022) : 1146–64. http://dx.doi.org/10.3934/energy.2022054.
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<abstract> <p>The year 2022 is characterized by a generalized energy crisis, which leads to steadily increasing electricity prices around the world, while the corresponding salaries remain stable. Therefore, examining trends in electricity prices relative to existing income levels can provide valuable insights into the overpricing/underpricing of energy consumption. In this article, we examine the tendencies of 35 European countries according to their national kWh prices and the average household incomes. We use a series of established clustering methods that leverage available information to reveal price and income patterns across Europe. We obtain important information on the balance between family earnings and electricity prices in each European country and are able to identify countries and regions that offer the most and least favorable economic conditions based on these two characteristics studied. Our analysis reveals the existence of four price and income patterns that reflect geographical differences across Europe. Countries such as Iceland, Norway, and Luxembourg exhibit the most favorable balance between prices and earnings. Conversely, electricity prices appear to be overpriced in many southern and eastern countries, with Portugal being the most prominent example of this phenomenon. In general, average household incomes become more satisfactory for European citizens as we move from east to west and south to north. In contrast, the respective national electricity prices do not follow this geographical pattern, leading to notable imbalances. After identifying significant cases of inflated prices, we investigate the respective causes of the observed situation with the aim of explaining this extreme behavior with exogenous factors. Finally, it becomes clear that the recent increase in energy prices should not be considered as a completely unexpected event, but rather as a phenomenon that has occurred and developed gradually over the years.</p> </abstract>
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Rum, Muhammad, et Bangkit Aditya Wirawan. « Energy Diplomacy : Proposed Strategic Roles For State-Owned Enterprises ». JURNAL ILMU SOSIAL 18, no 2 (3 avril 2020) : 164–80. http://dx.doi.org/10.14710/jis.18.2.2019.164-180.
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Natural resources endowment has always been a critical factor in supporting a country‟s development, particularly in the early stage, where firm productivity in industry and service sectors are still low. Such is the case with Indonesia, one of the largest oil-producing countries in the East Asia region, where the oil boom period in the 1970s has been able to fund many development projects. Although oil resource is waning over the last decade, the country is still among the largest producer in the Southeast Asian region, with an also growing demand for the burgeoning industry. This unique role should be able to strengthen Indonesia‟s position at the international level. That is why through this article, we try to propose a better picture of what could be done by scholars to help in formulating Indonesia‟s energy diplomacy. The purpose of this article is to have a look the role of Pertamina, a State-Owned Enterprise, in supporting international diplomacy while also executing their role in strengthening national energy security. Taking examples from other influential oil-seeking countries such as Japan and China and also from oil-producing „petrodollar‟ country such as Saudi Arabia, then Pertamina should actively engage in promoting development in targetted countries and maintaining bilateral ties. The conclusion of this research article is strong correlations between energy, diplomacy, and development assistance among those countries. Those nexuses will help Indonesia in exercising its “free and active” diplomatic stance in resolving various international issues such as the Freedom of Palestine and The Rohingya issue in Myanmar.
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JOHNSON, JEFF. « ENERGY ISSUES TAKE CENTER STAGE ». Chemical & ; Engineering News Archive 79, no 11 (12 mars 2001) : 45–48. http://dx.doi.org/10.1021/cen-v079n011.p045.
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Savchuk, Ramilya, Alexandr Cherkasov, Pavel Kondratiev et Semen Matskepladze. « About the state and problems of standardization of energy management in Russian enterprises ». Polityka Energetyczna – Energy Policy Journal 24, no 3 (22 septembre 2021) : 93–102. http://dx.doi.org/10.33223/epj/141096.
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Ikegami, Yasuyuki. « New Stage of Ocean Thermal Energy Conversion towards a Stable Renewable Energy Source - OTEC Grid Connection at Kumejima in Okinawa ». Journal of The Japan Institute of Marine Engineering 50, no 1 (2015) : 54–58. http://dx.doi.org/10.5988/jime.50.54.
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Viktoriia, Lovynska, Sytnyk Svitlana et Gritsan Yurii. « Energy potential of main forest-forming species of stands in the Northern Steppe, Ukraine ». Journal of Forest Science 64, No. 1 (29 janvier 2018) : 25–32. http://dx.doi.org/10.17221/33/2017-jfs.
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The study evaluated the energy potential of Scots pine and black locust stands within the Northern Steppe of Ukraine, in forest plantations subordinated to the State Agency of Forest Resources (Ukraine). This study defined general values of aboveground biomass components per age-class structure in the forest stands. Allocated carbon was calculated using the biomass components by age groups as follows: stem, branches and leaves (needles). Contribution of different age groups to carbon allocation was investigated. A key role of stem wood in the process of carbon allocation in the forest stands was shown. It was found that the maximum carbon budget was accumulated in stands of both forest-forming species aged 41–60 years. The models are made on a dependence of carbon allocation in the different components of aboveground biomass by age. Results of energy content in the aboveground biomass were presented in Scots pine and black locust stands within the surveyed area. The study has shown that the energy potential of carbon accumulated in the biomass of Scots pine stands amounted to 40.31 PJ, and that of black locust stands was 32.04 PJ. Development of forest ecosystems in the Steppe zone of Ukraine can result in the optimization of abiotic conditions on a local level under the influence of the global climate changes.
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Yuelong Gu, Chunyang Gong, Hui Chen, Jun Zhang et Zhixin Wang. « Series DC Arc Characteristic and Diagnosis Strategy for Distributed PV Power Generation ». Electrotehnica, Electronica, Automatica 70, no 4 (15 novembre 2022) : 1–10. http://dx.doi.org/10.46904/eea.22.70.4.1108001.
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In order to realize the nation’s goal of achieving carbon peaking before year 2030 and the carbon neutrality by year 2060, the installed capacity of distributed PV power generation system has increased year by year in China, which increases the probability of DC arc fault. The features of DC arc may be very weak under some conditions. When the current of DC arc is large and the voltage level of photovoltaic array is high, DC arc will be very stable, and it is hard to be detected. Besides, if there are many high-power devices around DC arc detector, the output signal of current sensor will be seriously interfered, and it will be more difficult to distinguish between normal state and arc fault state. DC arc can be divided into unstable combustion stage and stable combustion stage. When in stable combustion stage, DC arc is also hard to be detected. Fortunately, the features of DC arc are obvious when in unstable combustion stage and the value of current spectrum energy will significantly increase. When the spectrum energy exceeds the set threshold in five consecutive time windows, it is preliminarily determined that there is a suspected arc. If the spectrum energy still exceeds the set threshold within five consecutive time windows, it is finally determined that there is an arc fault, otherwise, short PV array for further diagnosis. If there is an arc fault, the fluctuation characteristics of DC arc will be enhanced and the loop current will go fluctuating intensely again, then spectrum energy calculated will exceed the set threshold and an arc fault alarm can be sent out. Taking into consideration the different features of DC arc’s unstable combustion stage and stable combustion stage, a Series DC arc diagnosis method based on current spectrum energy is proposed, which amplifies the fluctuation characteristics of arc current and keeps arc current fluctuating strongly for a long time by shorting the PV array. The spectrum energy is calculated through FFT analysis of each PV string’s current, compared to the calculated spectrum energy with the set threshold, and then decided whether DC arc fault exists. The results to an experimental platform verify the effectiveness of the arc detection method, which has advantages of low calculation cost and high accuracy.
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YOSHIDA, Shu, Koichi ITO, Yoshiharu AMANO, Keigo MATSUO, Takumi HASHIZUME et Kenji UETA. « C307 A MULTI-STAGE OPTIMAL RENEWAL PLANNING FOR AN ENERGY SUPPLY SYSTEM FROM ECONOMIC VIEWPOINT(Heat Pump-3) ». Proceedings of the International Conference on Power Engineering (ICOPE) 2009.3 (2009) : _3–173_—_3–178_. http://dx.doi.org/10.1299/jsmeicope.2009.3._3-173_.
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Kong, Jing Yi. « Ups and Downs and Nirvana : Three Decades of China's Nuclear Power ». Advanced Materials Research 962-965 (juin 2014) : 1827–29. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.1827.
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China’s development on nuclear power can be categorized into four stages, namely, difficult starting stage, stable developing stage, positive developing stage and rational developing stage. Presenting the three decades of ups and downs associated with China’s pursuit for such new energy as nuclear power, and further introduces the state of play and major characteristics of each period.
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SETO, EMANNUEL BAYU, et LEONARDUS HERU PRATOMO. « Integrasi PMSG dan DC-DC Buck-Boost Converter untuk Meregulasi Tegangan Keluaran menggunakan STM32VET407 ». ELKOMIKA : Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & ; Teknik Elektronika 12, no 2 (23 avril 2024) : 394. http://dx.doi.org/10.26760/elkomika.v12i2.394.
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ABSTRAKEnergi terbarukan saat ini banyak digunakan sebagai sumber energi baru ramah lingkungan. Imbasnya, sumber energi terbarukan dikembangkan secara signifikan seperti mikrohidro. Mikrohidro adalah alat yang mengkonversikan energi air menjadi energi listrik. Dalam sistem ini, mikrohidro terhubung dengan permanent magnet synchronous generator (PMSG) dan menghasilkan energi listrik tiga fasa dengan skala kecil. Untuk menghasilkan energi listrik yang stabil dan memiliki efisiensi tinggi, diperlukan penyearah dioda tiga fasa dan konverter DC-DC. Penelitian ini mengusulkan DC-DC Buck-Boost Converter dengan peregulasi tegangan keluaran. Dari hasil uji coba simulasi dan implementasi perangkat keras menggunakan microcontroller STM32VET407 sistem dapat berjalan baik, dimana tegangan keluaran selalu sesuai dengan referensi yang diinginkan.Kata kunci: Mikrohidro, Permanent Magnet Synchronous Generator (PMSG), Konverter DC-DC, DC-DC Buck-Boost converter ABSTRACTRenewable energy is currently widely used as a new source of environmentally friendly energy. As a result, renewable energy sources are significantly developed such as micro hydro. Micro hydro is a device that converts water energy into electrical energy. In this system, the microhydro is connected to a permanent magnet synchronous generator (PMSG) and produces three-phase electrical energy on a small scale. To produce stable and high-efficiency electrical energy, a three-phase diode rectifier and a DC-DC converter are required. This research proposes a DC-DC Buck-Boost Converter equipped with output voltage regulation. From the results of simulation trials and hardware implementation using the STM32VET407 microcontroller, the system can run well, it is evident that the output voltage is always in accordance with the desired reference.Keywords: Micro hydro; Permanent Magnet Synchronous Generator (PMSG), DCDC converter, DC-DC Buck-Boost converter
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Sari, Dany Perwita, et Pradhana Jati Budhi Laksana. « OPTIMIZATION BUILDING PERFORMANCE IN EARLY DESIGN STAGE USING INTEGRATED DYNAMIC MODEL ». MODUL 20, no 2 (15 décembre 2020) : 151–56. http://dx.doi.org/10.14710/mdl.20.2.2020.151-156.
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Considering the magnitude of energy loss in building, development of energy saving methods appears to be essential. Daylight plays a significant role in designing energy efficient buildings and improving visual comfort for the occupants. Many daylight analysis methods have been developed in this area. Most of these methods focus on opening maximization. These methods unfortunately might reduce comfort since it causes direct solar glare. There is a need for a reliable lighting simulation model to control the lighting strategy in early stage design. This study proposes a strategy for visualizing daylight analysis of buildings by using Integrated Dynamic Model (IDM). IDM is a combination of design tools used during the conceptual phase for holistic classroom that considers the building’s energy usage, daylight distribution, and thermal indoor environment. The optimization focus is related maximize the performance of the building envelope design. The purpose of this paper are; firstly, providing a new strategy for visualizing the predicting daylight while respecting architectural integrity. The second purpose is to facilitate the designer for choosing window and envelope design alternatives during early stages. The third is to maximize the positive impacts of daylight. Lastly, hopefully IDM could present a simplified simulation and analyze method with the timely, accurate and efficient process.
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Hovorukha, V. M. « TWO-STAGE DEGRADATION OF SOLID ORGANIC WASTE AND LIQUID FILTRATE ». Biotechnologia Acta 14, no 4 (août 2021) : 70–79. http://dx.doi.org/10.15407/biotech14.04.070.
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The accumulation of solid and liquid organic waste requires their treatment to develop energy biotechnologies and prevent environment pollution. Aim. The goal of the work was to study the efficiency of the purification of the filtrate from dissolved organic compounds by aerobic oxidation and methane fermentation. Methods. The standard methods were used to determine рН and redox potential (Eh), the gas composition, the content of short-chain fatty acids, the concentration of dissolved organic compounds counting to the total сarbon. The efficiency of two types of microbial metabolism for the degradation of soluble organic compounds of filtrate was compared. Results. The aerobic oxidation was established to provide 1.9 times more efficient removal of dissolved organic compounds, compared with the anaerobic methane fermentation. However, it provided CH4 yield 1 L/dm3 of filtrate (сarbon concentration — 1071 mg/L). The necessity to optimize the methods for purifying filtrate to increase the efficiency of the process was determined. Conclusions. The obtained results will be the basis to develop complex biotechnology providing not only the production of environmentally friendly energy H2 via the fermentation of solid food waste, but also the purification of filtrate to solve the ecological and energy (CH4 production) problem of society.
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Goswami, Yogi. « Renewable energy on the world stage ». Refocus 5, no 3 (mai 2004) : 60. http://dx.doi.org/10.1016/s1471-0846(04)00149-0.
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Liang, T. J., Y. C. Kuo et J. F. Chen. « Single-stage photovoltaic energy conversion system ». IEE Proceedings - Electric Power Applications 148, no 4 (2001) : 339. http://dx.doi.org/10.1049/ip-epa:20010436.
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Jeníček, V., et V. Krepl. « Energy and the European Union ». Agricultural Economics (Zemědělská ekonomika) 55, No. 1 (11 février 2009) : 1–11. http://dx.doi.org/10.17221/2501-agricecon.
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There exists no energy policy in the European Union, but rather a whole series of long-term goals setting its strategic orientation. Until 2000, when the Green Book named “Towards the European Strategy of Energy Supplies Securing“ was accepted, no real debate on the strategy of energy was held in the EU. The Green Book represents a key document of the European energy policy and it originated as a consequence of the fears of the European Committee regarding the growing energy dependence on the energy resources imports, from the politically not stable parts of the world. Among the three key points of the energy strategy, there belong stable supply of energy, acceptable energy prices and environment protection. With regard to the deepening European integration and interconnection of the individual member states economies, the decisions of one country also have an energy impact on the other states. Therefore, the cooperation among the individual members is necessary.
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Raue, C., H. M. Strehle, J. Stoldt, A. Schlegel, M. Richter et T. Langer. « Mehrstufiges multikriterielles Job-Shop-Scheduling*/Multi-Stage and Multi-Criterial Job-Shop-Scheduling ». wt Werkstattstechnik online 108, no 04 (2018) : 210–16. http://dx.doi.org/10.37544/1436-4980-2018-04-16.
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Energiepolitische Veränderungen erhöhen den Druck auf Produktionsunternehmen, erneuerbare Energiequellen zu nutzen. Deren Einbindung erfordert die Entwicklung neuer Ansätze zur Produktionsplanung und -steuerung (PPS). Dazu wird ein mehrstufiges simulationsbasiertes Verfahren für ein reales Job-Shop-Problem vorgeschlagen, welches die Shifting-Bottleneck-Heuristik zur Findung einer kundenorientierten Ausgangslösung auf Basis des prognostizierten Energieangebots nutzt. Vom resultierenden Lastprofil ausgehend wird eine Feinterminierung zur Optimierung von Lastspitzen unter Beachtung der Ergebnisse der Vorplanung durchgeführt. Auswirkungen kurzfristiger stochastischer Einflüsse werden überdies durch intelligente Produktionssteuerung, aber auch durch aktives Energie- und Lastmanagement kompensiert. Im vorliegenden Beitrag werden für das Anwendungsszenario Flexibilitätspotentiale abgeleitet und das Konzept des „ZIEL“-Systems erläutert. Darüber hinaus wird der aktuelle Bearbeitungsstand abgegrenzt und weiterführende Arbeiten vorgestellt. Taking responsibility for a sustained energy policy the industry is more and more forced to enhance their engagement in the use of renewable energy. To go beyond energy efficient equipment new approaches in production planning and control tailored to meet both economic and ecological goals are needed. Hence, a multistage simulation based procedure for a real-life oriented job shop production scenario is proposed. It combines a modified version of the Shifting Bottleneck Heuristic for gaining a production plan with energy supply constraints and a sophisticated energy simulation with Matlab Simulink. Short-term and stochastic effects are tackled with suited production control strategies as well as active energy- and load-management. In this paper flexibility options for the use case are derived and the concept of the „ZIEL“ system explained. The current work and the ongoing research are shown.
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Lobo, Francisco S. N. « Stable dark energy stars ». Classical and Quantum Gravity 23, no 5 (14 février 2006) : 1525–41. http://dx.doi.org/10.1088/0264-9381/23/5/006.
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Liu, Dan, et Wei Bing Guan. « Research on Energy Value of Dynamic Energy Budget ». Applied Mechanics and Materials 686 (octobre 2014) : 683–88. http://dx.doi.org/10.4028/www.scientific.net/amm.686.683.
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Dynamic Energy Budget software aims to identify simple quantitative rules for the organization of metabolism of individual organisms. It is always used to delineate reserves, as separate from structure. The energy density of Eriocheir sinensis was studied through DEB software in this paper. The results showed that Hepatopancreas energy density (32.17±3.77 KJ/g) was higher than gonad (23.19±2.86KJ/g), muscle (24.41±1.41 KJ/g) and carapace energy density (14.42±1.76 KJ/g). The difference between gonad (23.19±2.86KJ/g) and muscle energy density (4.41±1.41 KJ/g) of females and males was significant (P < 0.01), but not between muscle and carapace energy density (P > 0.05), and no difference between female and male individual in total energy (P = 0.887) at the stable stage. The linear relation between volume and weight of Eriocheir sinensis was gained by using regression analysis, V=6.104+1.117WW (R2=0.973, n=98), and the linear relation between total energy and dry weight was also gained, E=18.12DW-28.05 (R2=0.962 ,n=24).
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Sadre, Maxime. « Control of a legged robot ». Journal of the Mechanical Behavior of Materials 24, no 1-2 (1 mai 2015) : 53–57. http://dx.doi.org/10.1515/jmbm-2015-0006.
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AbstractThis paper deals with the control of hopping and running systems that interact intermittently with the environment. The control, based on a nonlinear energy reference model, has the main task of conferring to the system, a periodic stable behavior. This approach may be used for gait generation, nominal stance stabilization, energy shaping, and optimization.
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İsmət oğlu Cəfərov, İmran. « SOLUTIONS TO ENERGY SAVING PROBLEMS IN BUILDING HEATING ». SCIENTIFIC RESEARCH 08, no 4 (27 avril 2022) : 207–10. http://dx.doi.org/10.36719/2789-6919/08/207-210.
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Binaların isidilməsi zamanı enerji xərclərinin minimuma endirilməsi imkanlarının təhlili artıq şəhərsalma sənədlərinin, qəsəbələrin, ayrı-ayrı rayonların və müəssisələrin inkişafı və planlaşdırılması üzrə baş planların işlənib hazırlanması mərhələsində başlamalıdır. Layihələndirmə mövcud bina və tikililərin, eləcə də təbii obyektlərin təsirini nəzərə almaqla binaların yerə yerləşdirilməsi variantlarının qiymətləndirilməsi ilə aparılmalıdır. Açar sözlər: enerjiyə qənaət, binaların isidilməsi, istilik enerjisi, günəş enerjisi, bərpa olunan enerji. Imran Ismat Jafarov SOLUTIONS TO ENERGY SAVING PROBLEMS IN BUILDING HEATING Abstract The analysis of the possibilities of minimizing energy costs during the heating of buildings should begin at the stage of development of master plans for the development and planning of urban planning documents, settlements, individual districts and enterprises. The design should be based on an assessment of the location of the buildings, taking into account the impact of existing buildings and structures, as well as natural objects. Key words: energy saving, heating of buildings, thermal energy, solar energy, renewable energy.
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Sakimura, Koichiro, Shinichi Nakahara, Kohei Kawaguchi et Masao Eto. « Staged Management of High-Energy Tibia Fractures ». Orthopedics & ; Traumatology 61, no 1 (2012) : 5–8. http://dx.doi.org/10.5035/nishiseisai.61.5.
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Nazarenko, Ivan, Oleg Dedov, Anatoly Svidersky et Nicolay Ruchinsky. « Research of energy-saving vibration machines with account of the stress-strain state of technological environment ». IMK-14 - Istrazivanje i razvoj 26, no 4 (2020) : 123–26. http://dx.doi.org/10.5937/imk2004123n.
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An analytical method for determining the influence of a process medium on the dynamics of the working bodies of vibrating machines is considered. The results of the research are presented, which made it possible to identify the zones of effective action of parameters and characteristics of the "machine - environment" system to ensure the high quality of the compaction process, which is based on the idea of purposeful use of the elastic characteristics of a common vibration system. The scientific idea is put forward, which consists in the fact that during the study of a particular process the mathematical model of the vibration system "machine-environment" should be determined on the basis of taking into account the internal structure of these subsystems as a single one, despite their different physical nature and structure. The theoretical substantiation of the possibility of creating bulk molding Vibration Machines with highly effective parameters of energy intensity and material consumption for various conditions for the formation of concrete and reinforced concrete products is given in the paper. This is due to the creation and rational use of the regularities of changes in the internal (elastic-inertial and dissipative) properties of the "machine-environment" system in the regime, which is approximate to the mode of its free oscillations.
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Ramayani, Dewi, Yanuar Hamzah, Erman Taer, Novi Yanti et Afriwandi Apriwandi. « Analysis of Activated Carbon Monolith Derived from Carrot Juice Waste for Supercapacitor Electrode Application ». Journal of Aceh Physics Society 10, no 2 (14 avril 2021) : 26–31. http://dx.doi.org/10.24815/jacps.v10i2.18392.
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Abstrak. Pengembangan sistem penyimpanan energi elektrokimia yang efektif dan efisien menjadi sangat penting pada era evolusi teknologi dan industri modern saat ini. Penelitian ini mengemukakan karbon aktif sebagai bahan dasar material elektroda untuk diaplikasikan pada piranti penyimpan energi, khsusunya superkapasitor melalui analisa densitas, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) dan Cyclic Voltammetry (CV). Karbon aktif berbentuk monolit disiapkan dari ampas jus wortel melalui pendekatan pirolisis satu tahap terintegrasi dan aktivasi kimia KOH. Proses pirolisis satu tahap terintegrasi dilakukan melalui penggabungan karbonisasi dan aktivasi fisika dalam atmosfer gas N2/CO2. Berdasarkan analisis data, karbon aktif menunjukkan sifat amorf yang normal dan sifat porositas terkonfirmasi. Lebih lanjut, sifat elekrokimia dievaluasi menggunakan metode Cyclic Voltammetry (CV) pada sistem dua elektroda. Kapasitansi spesifik yang dihasilkan sebesar 155 F/g dalam elektrolit 1 M H2SO4 dengan energi spesifik dan daya spesifik adalah 21,52 Wh/kg dan 77,57 W/kg. Berdasarkan analisa ini maka ampas jus wortel terkonfirmasi berpotensi sebagai karbon aktif untuk elektroda yang diaplikasikan dalam piranti penyimpan energi superkapasitor.Abstract. The development of an effective and efficient electrochemical energy storage system is very important in today's era of technological evolution and the modern industry. This research suggests that activated carbon is the raw material for electrode materials to be applied to energy storage devices, especially supercapacitors through density analysis, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), and Cyclic Voltammetry (CV). Activated carbon in the monolith form derived from carrot juice waste was prepared through a one-stage integrated pyrolysis approach and chemical activation of KOH. An integrated one-stage pyrolysis process was carried out by combining carbonization and physical activation in an N2/CO2 gas atmosphere. Based on data analysis, activated carbon performed normal amorphous behavior with confirmed porosity features. Furthermore, the electrochemical properties were evaluated using the Cyclic Voltammetry (CV) method at the two-electrode system. The specific capacitance was found as high as 155 F/g in the 1 M H2SO4 aqueous electrolyte with specific energy and specific power as high as 21.52 Wh/kg and 77.57 W/kg, respectively. Based on this analysis, the carrot juice waste has been confirmed to have the potential as activated carbon for the electrodes applied in supercapacitor energy storage technology.Keywords: Carrot Juice Waste, Activated Carbon, Electrode Materials, Supercapacitor
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Kompanichenko, V. N. « Three stages of the origin of life process : bifurcation, stabilization and inversion ». International Journal of Astrobiology 7, no 1 (janvier 2008) : 27–46. http://dx.doi.org/10.1017/s1473550407003953.
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AbstractThe principal succession of transformations of a prebiotic microsystem leading to its transition into the primary living state is theoretically substantiated. For the first stage of the succession, a significant change in the external conditions constrains an organic microsystem to leave the current stable state with the following transition into a new stable state through the unstable critical (bifurcation) point. At the bifurcation point the microsystem acquires the original properties without which life cannot exist (self-maintaining heterogeneous structure, incessant fluctuations and rearrangement of molecules, exchange with the surroundings by matter and energy, etc.). During the second stage its unstable state stabilizes relatively by means of the balanced oscillations around the bifurcation point (the paradoxical state of ‘stabilized instability’ appears). The third stage is characterized with the radical turn in the network of chemical reactions: the free energy contribution begins to prevail over the entropy contribution. As a result, constructive transformations proceed faster than destructive transformations. At this stage the key properties of biological organization appear: the ability to concentrate free energy and information, intensified counteraction to external influences, expedient behaviour and persistent self-renovation. On the early Earth, such successive transformation of organic matter occurred in the changeable conditions of a hydrothermal medium. Some new methods for experimental and theoretical research in the origin of life field are suggested.