Journal articles on the topic 'Isolated power converts'
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Sachdev, Hira Singh, and Ashok Kumar Akella. "Small Hydro Power Schemes: Technical Aspects." International Journal of Advances in Applied Sciences 6, no. 1 (March 1, 2017): 55. http://dx.doi.org/10.11591/ijaas.v6.i1.pp55-63.
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<p>Small hydro systems play a major role in meeting power requirements of remote, isolated, hilly areas in a decentralized manner by tapping water streams, rivulets and canals of small discharge. Small hydroelectric system captures the energy in flowing water and converts it to electricity.</p>Of all the non-conventional renewable energy sources, small hydro stands first as it is more resourceful, reduces system losses, environment friendly, non-consumptive and source is renewable due to their enormous advantages over large hydro and other power plants, lot of small hydro-power plants have come up across the world to meet the ever increasing demand of electrical energy. Lowering the high initial cost of the small hydro-power plants and its popularization is today’s challenges. This paper describes basic techniques design of the small hydro-power development.
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Ma, Runzhuo. "Analysis and Design Based on the Operation Mode of Power Electronic Transformer in Smart Grid." Journal of Physics: Conference Series 2108, no. 1 (November 1, 2021): 012073. http://dx.doi.org/10.1088/1742-6596/2108/1/012073.
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Abstract Power electronic transformers(PET) are the key energy conversion equipment in the operation of modern smart grids, the main function of PET is to achieve the conversion of AC voltage to AC voltage, while taking into account the DC ports. This article mainly studies three-stage power electronic transformers based on three-phase uncontrolled rectifier, full-bridge isolated DC-DC converter and three-phase inverter. The operation mechanism and actual working process of the three parts of the PET are analyzed respectively, and the transformer is simulated and analyzed based on the Matlab/Simulink simulation platform. The rectifier converts the AC voltage on the grid side into a rippled DC voltage; the DC-DC converter transforms the obtained DC voltage, taking into account the access of the DC ports; the inverter converts the obtained DC voltage into AC voltage through unipolar modulation and connects to the grid. The experimental results show that the PET constructed in this way can operate safely and stably, which has good voltage conversion and electrical isolation functions, and can be connected to DC loads.
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Adnan, Muhammad, Rashid Mehmood, Muhammad Waseem Imtiaz, Sajjad Ahmed, Muhammad Shahmeel, Muhammad Okash ur Rehman, Saira Zahoor, and Muhammad Mujahid Iqbal. "Efficient Physical and Multidisciplinary Approaches in Combinations of Nanoparticles towards Power Generations, Energies Production Methods and Photocatalysis Mechanism." Scholars Bulletin 8, no. 3 (March 10, 2022): 84–88. http://dx.doi.org/10.36348/sb.2022.v08i03.002.
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To progress toward sustainable growth, future hydro-power development must pay a bit more attention towards how changing climate may impact hydropower output, as well as make massive action to limit the environmental costs borne by people who live near dams. Long term projections help in providing data for power network risk analysis as well as identifying wind power generation potential in particular places, delivering important data for electricity planners. Hydro-electric power system is an enhanced energy process because it effectively converts mechanical power into grid power, but both are high-energy methods. The utilization of wind turbines for renewable power source has turned out to be one of the greatest viable alternate wells-prings of electricity age because of the little recompense, for instance, being profitable and efficient and environment friendly. Many foundations, organizations, associations, and experts have demonstrated that wind turbines are presumed to comprehend the imperativeness order. In compared to conventional power plants, although wind-power plants have little impact on the environment, concern exists over the noise produced by the turbine blades and visual impacts to the landscape and turbine blade. While wind turbines are connected to the small scale or isolated network, the power product from another source should be varied in reply to these variant and change in sequence to retain system density and voltage with in pre-set limit.
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Nik Azmi, Nik Mahmood, Nazlee Faisal Ghazali, Ahmad Fikri, and Md Abbas Ali. "Studies on Power Generation and Wastewater Treatment Using Modified Single Chamber Microbial Fuel Cell." Advanced Materials Research 1113 (July 2015): 823–27. http://dx.doi.org/10.4028/www.scientific.net/amr.1113.823.
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A membrane-less and mediator-less system was designed and tested with wastewater sample as fuel to generate electricity. Microorganisms were first isolated from the wastewater sample to pure culture and were used as the ‘machinery’ that converts wastewater into energy. The wastewater samples were treated either by sterilization or non-sterilization methods. These tests were run using a modified air-cathode single chamber microbial fuel cell (MFC). By sterilizing the wastewater, the calculated power density was much lower compared to non-sterilized wastewater indicating a significant role of microbial activity in the SCMFC system and substrate availability. Furthermore, mixed culture was observed to give larger power density compared to an individual microbe (18.42 ± 5.84 mW/m2 for mixed culture and 8.82 ± 4.56 mW/m2 to 9.46 ± 4.87 mW/m2 for individual microbe, Bukholderi capecia and Acidovorax sp. respectively) to prove that larger power value could be achieved with a mixed microbial system. In addition, the system proved to remove 68.57% of chemical oxygen demand (COD) of the wastewater sample tested. In conclusion, the designed SCMFC has been proven capable of power generation and wastewater treatment comparable to other SCMFCs to date.
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Bustos, María, Humberto Ibarra, and Jenny Dussán. "The Golden Activity of Lysinibacillus sphaericus: New Insights on Gold Accumulation and Possible Nanoparticles Biosynthesis." Materials 11, no. 9 (September 2, 2018): 1587. http://dx.doi.org/10.3390/ma11091587.
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Power struggles surrounding the increasing economic development of gold mining give rise to severe environmental and social problems. Two new strains of Lysinibacillus sphaericus were isolated from an area of active alluvial gold mining exploitation at El Bagre, Antioquia. The absorption capacity of these strains and some of the L. sphaericus Microbiological Research Center (CIMIC) collection (CBAM5, OT4b.31, III(3)7) were evaluated by spectrophotometry according to a calibration gold curve of HAuCl4− with concentrations between 0 µg/mL and 100 µg/mL. Bioassays with living biomass were carried out with an initial gold concentration of 60 µg/mL. Their sorption capacity was evident, reaching percentages of gold removal between 25% and 85% in the first 2 h and 75% to 95% after 48 h. Biosynthesis of possible gold nanoparticles (AuNPs) in assays with living biomass was also observed. Metal sorption was evaluated using scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) analysis. The sorption and fabrication capacity exhibited by the evaluated strains of L. sphaericus converts this microorganism into a potential alternative for biomining processes, especially those related to gold extraction.
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HANAMOTO, T., H. YAMADA, S. TOOSI, N. F. MAILAH, and M. NORHISAM. "DDPWM-Based Power Conversion System Using a Matrix Converter for an Isolated Power Supply." Journal of the Japan Society of Applied Electromagnetics and Mechanics 23, no. 3 (2015): 573–78. http://dx.doi.org/10.14243/jsaem.23.573.
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Malyarchuk, Boris A., Miroslava V. Derenko, and Galina A. Denisova. "R577X polymorphism of alpha-actinin-3 in human populations of North-Eastern Asia." Ecological genetics 15, no. 1 (March 15, 2017): 50. http://dx.doi.org/10.17816/ecogen15150-56.
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Background. In polymorphism rs1815739, a C → T transition converts arginine to a premature stop-codon at residue 577 of the alpha-actinin-3 (ACTN3) protein (R577X polymorphism). This polymorphism may affect muscle performance, and the derived 577X allele has been found to be under-represented in sprint/power athletes. In addition, loss of alpha-actinin-3 results in a shift in muscle metabolism toward the more efficient aerobic pathway, thus pointing that this polymorphism may have been involved in enhancing the capability for hunting and for cold adaptation. Here, we study rs1815739 polymorphism in native populations (Chukchi, Koryaks and Evens) and newcomers (Russians) of North-Eastern Asia. Materials and methods. Genomic DNA was isolated from peripheral blood. ACTN3 genotypes for rs1815739 locus were established by enzymatic digestion of amplicons with DdeI. Heterozygotes TT were confirmed by DNA sequencing. In addition, data on exome variation in Siberian populations were analyzed. Results. Lowered frequencies (less than 40%) of “mutant” allele rs1815739-T were found in studied populations of North-Eastern Asia. Analysis of exome data has shown that haplotype comprising the rs1815739-T allele reaches the highest frequencies in populations of Southern and Central Siberia, while it is rather rare in the north-east of Siberia. Conclusion. The results obtained contradict the hypothesis that the rs1815739 polymorphism may have been involved in cold adaptation of North-East Siberians.
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Yao, Yunpeng, Shen Xu, Shengli Lu, and Weifeng Sun. "Closed-Form Second-Order Power Transmission Characteristic Model of the Isolated Dual Active Bridge Converter." Journal of Clean Energy Technologies 4, no. 6 (2016): 384–88. http://dx.doi.org/10.18178/jocet.2016.4.6.318.
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Dorneles Callegaro, Alan, Denizar Cruz Martins, and Ivo Barbi. "Isolated Single-phase High Power Factor Rectifier Using Zeta Converter Operating In Dcm With Non-dissipative Snubber." Eletrônica de Potência 19, no. 4 (November 1, 2014): 423–29. http://dx.doi.org/10.18618/rep.2014.4.423429.
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Murdianto, Farid Dwi, Indhana Sudiharto, and Eni Wulandari. "Performance Evaluation Zeta Converter Using PI Controller for Energy Management in DC Nanogrid Isolated System." INTEK: Jurnal Penelitian 8, no. 1 (July 25, 2021): 37. http://dx.doi.org/10.31963/intek.v8i1.2651.
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Renewable energy is needed as an alternative energy source. One of the implementations of renewable energy is the Solar Power Plant (PLTS). PLTS is a component that uses solar cells to convert solar energy into electrical energy. Unfortunately, the output power of this solar cell depends on the intensity of the light which causes the output power to enter the load to be unstable. Sometimes the PV power decrease because of the shading effect. From this problem a converter is needed to keep the system output voltage. The converter used in this research is the zeta converter. This Zeta converter can operate like a buck boost converter. The output of the system used is not stable. So that to stabilize it requires good control. In this paper using PI controller to control this system in order to keep the output system stable. 3. The error generated using the PI Control on the system is only 0.34%.
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Johar, Harminder Singh, Abhijit Bhattacharyya, and Srinivas Rao S. "Fault Tolerant Power Supply for Aircraft Store Interface." Defence Science Journal 72, no. 5 (November 1, 2022): 679–86. http://dx.doi.org/10.14429/dsj.72.17737.
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This paper brings out the design of a fault-tolerant power supply unit for the aircraft-store interface. This switched mode power supply provides multiple 30 V regulated and isolated DC outputs required for pre-launch preparations and auto-launch operations of avionic sub-systems in a store. 3Ø-115V-400Hz-AC supply as well as 27V-DC supply are available from a fighter aircraft for powering up of any store. Power (wattage) output from 27V/10A DC is inadequate to power up various onboard avionic sub-systems in guided stores involving seekers and other avionics. Hence, it is planned to convert available high power 3Ø-115V-400Hz-AC supply for applications requiring higher wattages (of the order of 500 watts or more). This power supply provides multiple output options of 30V regulated and isolated DC supply with multiple input supplies from Aircraft, viz. 3Ø-115V-400Hz-AC, 1Ø-115V-400Hz-AC and 27V DC. One of the outputs provided is with hold-up capacitors, to cater for any input power interruptions as per requirements of MIL-STD-704F and GOST-19705-89 standards. This power supply is a ready-to-connect device and essentially consists of housing, components of DC to DC conversions, EMI/EMC filters, solid state power controllers, control switches, and control circuitry for monitoring signals.
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Song, Jia Mei, Dong Ping Sun, Lei Zhao, Hong Ju Jiang, and Chun Lin Zhu. "High Power Generation by a Strain of Facultative Anaerobe in Double-Chamber Microbial Fuel Cell." Advanced Materials Research 347-353 (October 2011): 2616–21. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.2616.
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Microbial Fuel Cells (MFCs) are systems that can convert chemical energy into electrical energy by biological oxidation, current effort to improve the power output is limited by the lack of knowledge about the electrochemical activity bacteria and researches on the power generation mechanisms of pure strains are rare. In this study, the exoelectrogenic (”exo” for exocellular) bacterium staphylococcus SJ-1 was directly isolated from the MFC, which was stably run for 90 days. Cyclic Voltammetry (CV) indicated that temporary mediator produced by SJ-1 may take the work of transferring electron. A new built double-chamber MFC was inoculated with pure SJ-1, and after 40 days enrichment, the system produced 520mW/m2 power density and the highest open circuit voltage (OCV) reached to 616mV, the power output was higher than most of the single-strain MFCs reported.
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Foley, Michael, Rory Smead, Patrick Forber, and Christoph Riedl. "Avoiding the bullies: The resilience of cooperation among unequals." PLOS Computational Biology 17, no. 4 (April 7, 2021): e1008847. http://dx.doi.org/10.1371/journal.pcbi.1008847.
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Can egalitarian norms or conventions survive the presence of dominant individuals who are ensured of victory in conflicts? We investigate the interaction of power asymmetry and partner choice in games of conflict over a contested resource. Previous models of cooperation do not include both power inequality and partner choice. Furthermore, models that do include power inequalities assume a static game where a bully’s advantage does not change. They have therefore not attempted to model complex and realistic properties of social interaction. Here, we introduce three models to study the emergence and resilience of cooperation among unequals when interaction is random, when individuals can choose their partners, and where power asymmetries dynamically depend on accumulated payoffs. We find that the ability to avoid bullies with higher competitive ability afforded by partner choice mostly restores cooperative conventions and that the competitive hierarchy never forms. Partner choice counteracts the hyper dominance of bullies who are isolated in the network and eliminates the need for others to coordinate in a coalition. When competitive ability dynamically depends on cumulative payoffs, complex cycles of coupled network-strategy-rank changes emerge. Effective collaborators gain popularity (and thus power), adopt aggressive behavior, get isolated, and ultimately lose power. Neither the network nor behavior converge to a stable equilibrium. Despite the instability of power dynamics, the cooperative convention in the population remains stable overall and long-term inequality is completely eliminated. The interaction between partner choice and dynamic power asymmetry is crucial for these results: without partner choice, bullies cannot be isolated, and without dynamic power asymmetry, bullies do not lose their power even when isolated. We analytically identify a single critical point that marks a phase transition in all three iterations of our models. This critical point is where the first individual breaks from the convention and cycles start to emerge.
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Javadpoor, S., and D. Nazarpour. "Modeling a PV-FC-Hydrogen Hybrid Power Generation System." Engineering, Technology & Applied Science Research 7, no. 2 (April 24, 2017): 1455–59. http://dx.doi.org/10.48084/etasr.760.
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Electrical grid expansion onto remote areas is often not cost-effective and/or technologically feasible. Thus, isolated electrical systems are preferred in such cases. This paper focuses on a hybrid photovoltaic (PV)-hydrogen/fuel cell (FC) system which basic components include a PV, a FC, alkaline water electrolysis and a hydrogen gas tank. To increase the response rate, supercapacitors or small batteries are usually employed in such systems. This study focuses on the dynamics of the system. In the suggested structure, the PV is used as the main source of power. The FC is connected to the load in parallel with the PV by a transducer in order to inject the differential power while reducing power generation in relation to power consumption. An electrolyzer is used to convert the surplus power to hydrogen. This study studies a conventional hybrid photovoltaic-hydrogen/fuel cell system to evaluate different loading behaviors. Software modeling is done for the suggested hybrid system using MATLAB/SIMULINK.
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Dhungana, Pradip, and Jarina Rajbhandari. "Integrated Method of Pretreatment, Saccharification and Electro-Fermentation of Saccharum Spontaneum to Produce Bioethanol Using Microbial Consortium." ECS Meeting Abstracts MA2022-02, no. 64 (October 9, 2022): 2383. http://dx.doi.org/10.1149/ma2022-02642383mtgabs.
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Production of lignocellulosic ethanol using microbial consortium can be an economical strategy. Consortium of ligninolytic and cellulolytic microbe(s) that can depolymerize lignin and hydrolyze cellulose along with fermenting yeast (CDBT-2) can replace the separate techniques used for biomass pretreatment and hydrolysis prior to fermentation. So, the aim of this study was to screen fungi capable of producing laccase (lignin depolymerizing enzyme) and cellulase (converts cellulose to fermentable sugars), and use the strains along with Saccharomyces cerevisiae (CDBT-2) to develop an integrated method of simultaneous pretreatment saccharification and electro-fermentation of Saccharum spontaneum powder to produce ethanol. 18-s rRNA sequencing and BLAST analysis of screened isolates confirmed, cellulolytic isolate (F1) resembled as Aspergillus niger and, ligninocellulolytic isolate (F2) resembled to Ganoderma sessile. These fungi were used along with CDBT2 for ethanol production. Different consortiums sets of these isolates were tested for fermentation efficiency. All the analysis were done using crude untreated as well as hot water pretreated S. spontaneum powder to compare the ethanol production efficiency. In controlled environment of 28oC, shaking at 80 rpm and 5.0 pH, culture with consortium of G. sessile and CDBT2 produced higher ethanol with yield 57 mg/g biomass powder followed by consortium of G. sessile, A. niger and CDBT2 with yield of 44±0.18 mg/g biomass. Monoculture of G. sessile produced higher amount of phenol ie 292.48±17.74 µg/mL. Similarly, G. sessile, A. niger and CDBT2 consortium produced higher furfural of 58.48±3.86 µg/mL. However, the amount of phenol and furfural generated were very low in both cases. The ethanol yield was higher in crude biomass compared to hot water pretreated S. spontaneum powder. In addition, electro-fermentation of crude S. spontaneum enhanced ethanol production by 12% with G. sessile and CDBT2 consortium while 18% with the set of G. sessile, A. niger and CDBT2 consortium. This monophasic method of integrated pretreatment saccharification and electro-fermentation can be an alternative approach for lignocellulosic bioethanol production as it does not require separate pretreatment and fermentation approach. Keywords: Bioethanol, Saccharum spontaneum, microbial consortium, simultaneous saccharification and fermentation, and electro-fermentation Figure 1
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Wu, Li Chun, Chi Huang, Hsin Hui Wang, and Ying Chien Chung. "High Bioelectricity Generation by Microbial Fuel Cells (MFCs) Inoculated Enterococcus faecium YC 201." Advanced Materials Research 838-841 (November 2013): 2461–65. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.2461.
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Microbial fuel cells, also known as biological fuel cells, use bacteria to convert biodegradable materials such as wastewater pollutants into electricity. However, limited studies revealed the high bioelectricity generation using a mediator-less MFC. This study isolated an exoelectrogen E. faecium YC 201, inoculated to a mediator-less MFC and obtained a high power density. Results show that the power generation reached a maximum of 121.3 ± 4.2 mW/m2 that was higher than those of other similar MFCs reported in the past literature. Substrate types significantly affected electricity generation and the optimal substrate for electricity generation was glucose. The riboflavin was identified as possible mediator for the mediator-less MFC that was self-excreted by E. faecium YC 201. To our knowledge, this is the first time to clearly reveal the electricity characteristics of exoelectrogen E. faecium YC 210.
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To, Duyen T. M., Ngoc Pham, and Hoa T. Pham. "Evaluating the effects of chloride on the performance of microbial fuel cells for wastewater treatment." Ministry of Science and Technology, Vietnam 64, no. 2 (June 15, 2022): 99–104. http://dx.doi.org/10.31276/vjste.64(2).99-104.
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Up to 5% of wastewater generated worldwide is highly saline effluent. Microbial fuel cells (MFCs) have been considered as a promising saline wastewater treatment, which uses microorganisms to convert organic compounds into electrical energy. This study investigated lab-scale MFCs to evaluate the effect of chloride at different concentrations (0, 5, 10 and 20 g/l NaCl) on the performance of the MFC by examining its electrical generation and wastewater treatment efficiency. Increasing NaCl concentration led to a decrease in power generation with maximum power at 30, 18.7, 18.8, and 5.2 mW/m2 corresponding to 0, 5, 10, and 20 g/l of NaCl, respectively. The COD removal efficiency of the four treatments did not significantly vary (p>0.05) and reached 65.9% to 78.7%. Acidovorax spp. was isolated from the treatment without NaCl while Pseudomonas citronellolis was isolated from the treatments containing 10 and 20 g/l NaCl. Pseudomonas citronellolis can be used as a potential inoculum for MFCs treating highly saline wastewater based on its high electrical generation ability (606.8 mW/m2) based on inoculation of this pure strain into the mini MFC.
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Wu, Jinn-Chang, Hurng-Liahng Jou, Fu-Zen Chen, and Jung-Peng Li. "Cascaded AC-DC Power Conversion Interface for Charging Battery." Electronics 12, no. 5 (March 1, 2023): 1192. http://dx.doi.org/10.3390/electronics12051192.
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This paper develops a cascaded AC-DC power conversion interface (CADPCI) to convert AC power to charge the battery set. The proposed CADPCI is composed of a cascaded converter (CC) and a dual-input buck converter (DIBC). The CC is formed by connecting a full-bridge converter (FBC) and a bridgeless rectifier (BLR) in series. The CADPCI generates an 11-level input voltage and performs unity power factor correction. The switching loss is reduced because only the FBC with a lower DC port voltage is switched at a high frequency. The DIBC uses a buck converter and a selection switch set to generate a two-level DC voltage on the DC port of the BLR. By controlling the DC input voltage of the buck converter, the injected power of the BLR can match the input power of the utility. Therefore, the FBC does not require to handle the real power, saving an isolated converter for regulating the DC port voltage of the FBC, thus simplifying the power circuit of the CC. The buck converter also acts as a DC active filter to filter out low-frequency ripples of the charging current. A prototype is constructed to verify the performance of the proposed CADPCI.
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Kumrey, G. R., and S. K. Mahobia. "STUDY AND DESIGN OF SINGLE PHASE CONVERTER USING OF SINGLE PHASE TRANSFORMER." International Journal of Research -GRANTHAALAYAH 4, no. 8 (August 31, 2016): 46–51. http://dx.doi.org/10.29121/granthaalayah.v4.i8.2016.2562.
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The field of electrical transformer are most important equipment which is use to convert ac voltage or current like lower to higher , higher to lower without change in the frequency . its primary side and secondary side are isolate from each other and it can higher or lower voltage level the apparent value of electrical passive element like inductive , resistive . It use to transfer electrical energy for long distance with higher voltage level .the electrical power transmission,distribution through transformer for factories and home . AC supply can easily generated by a convenient voltage and transformed into much higher voltage for transmission and distribution purpose.
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A. Anu Priya and Dr. S. Senthil Kumar. "Review on Converters used in Electric Vehicle Drive System." International Journal for Modern Trends in Science and Technology 9, no. 01 (January 24, 2023): 1–9. http://dx.doi.org/10.46501/ijmtst0901001.
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Electric vehicles (EVs) are gaining popularity due to their improved performance and environmentally friendly nature. The effectiveness of EVs depends on the successful interface between their energy storage systems and propulsion motor. One of the key components of an EV is the motor converter, which converts the electrical energy stored in the battery into mechanical energy that powers the vehicle's propulsion system. The motor converter used in EV drive system is reviewed. Non- isolated converter for DC/DC conversion and DC/AC converter to drive the motor are stated. Despite their usefulness, EV converters have some drawbacks, large number of components, high current stress, high switching loss, slow dynamic response, and computational complexity. This review examines various EV converter configurations, highlighting their topology, features, components, operation, strengths, and weaknesses.
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Su, Jung-Jeng, Yen-Jung Chen, Yuan-Chih Chang, and Szu-Ching Tang. "Isolation of sulfide oxidisers for desulfurising biogas produced from anaerobic piggery wastewater treatment in Taiwan." Australian Journal of Experimental Agriculture 48, no. 2 (2008): 193. http://dx.doi.org/10.1071/ea07248.
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This study aimed to improve the utilisation of biogas in pig farms, the promotion of biogas use and the reduction of greenhouse gas (i.e. methane, carbon dioxide, and nitrous oxide) emissions to the atmosphere. Sulfur oxidisers can convert sulfide (S2–) to sulfur (S0) and even sulfate (SO42–). Strains of CYAS-1, CYAS-2, SW-1, SW-2, and SW-3 were isolated from environmental samples and proven to have capabilities of sulfide oxidation by growing them in 150 mL liquid media with 1.5 g sulfur powder. An increase in sulfate concentration was used to select sulfide oxidisers. Strains CYAS-1 and CYAS-2, which both had significant sulfide oxidation capability, were isolated from the sludge of piggery wastewater treatment facilities. Moreover, strains SW-1, SW-2, and SW-3 were isolated from a pilot-scale biogas bio-filter (BBF) reactor. The experimental results showed that strain CYAS-1 (identified as Acinetobacter spp.), grown in diluted trypticase soy broth (TSB) with sulfur powder, increased the concentrations of SO42– from 17.2 ± 0.5 to 23.8 ± 1.0 mg/L (38.4% increase). Strain CYAS-2 (identified as Corynebacterium spp.), grown in diluted TSB with sulfur powder, increased concentrations of SO42– from 17.7 ± 0.1 to 25.9 ± 0.9 mg/L (47.0% increase). Concentrations of SO42– were increased 40.5, 33.6, and 29.7% in the presence of strains SW-1 (Candida kruse/inconspicua; 96.2% identity), SW-2 (Candida parapsilosis; 93.2% identity), and SW-3 (Trichosporon mucoides; 95.7% identity), respectively.
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Arboleda Avilés, Daniel Gonzalo, Oscar Fernando Núñez Barrionuevo, Omar Fernando Sánchez Olmedo, Billy Daniel Chinchin Piñan, Daniel Alexander Arboleda Briones, and Raúl Alfonso Bahamonde Soria. "Application of a direct current circuit to pick up and to store bioelectricity produced by microbial fuel cells." Revista Colombiana de Química 48, no. 3 (September 1, 2019): 26–35. http://dx.doi.org/10.15446/rev.colomb.quim.v48n3.77011.
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Every year the demand for energy worldwide is increasing. There are some alternatives to reduce these problems, such as clean energy or renewable energy. A particular alternative is the microbial fuel cells. These cells are biochemical reactors that convert chemical energy into electricity. The present research evaluated the dairy serum to produce bioelectricity from micro fuel cells (MFC) that were constructed with low-cost materials and with isolated bacteria in anaerobic sediments, located in Ecuadorian national territory, producing maximum voltages of 0.830 V in the circuit and a maximum power density of 30mW / m2. This low voltage was worked with 50 mL MFCs and with an output voltage of 300 mV. Under these conditions, a FLYBACK lift circuit isolated by the transformer was designed. This new circuit could increase the voltage from 30 mV to enough voltage to light a 2.5 V LED. Therefore, the energy produced by the MFC can be directly used to light a LED and to charge capacitors. This study shows that these MFCs, together with the designed circuit, could be used potentially to generate clean energy.
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Obaid, Waleed, Abdul-Kadir Hamid, and Chaouki Ghenai. "Hybrid solar/wind/diesel water pumping system in Dubai, United Arab Emirates." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 3 (June 1, 2021): 2062. http://dx.doi.org/10.11591/ijece.v11i3.pp2062-2067.
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This paper proposes a hybrid power system design for water pumping system in Dubai (Latitude 25.25 °N and Longitude 55 °E), United Arab Emirates using solar photovoltaic (PV) panels, wind turbines, and diesel generator. The proposed design considers the changes in weather conditions (humidity percentage, temperature in celsius, and wind speed in m/s) that directly affect solar irradiance values which alter the performance of the hybrid system. The proposed design deals with the problem of rare rainy days in Dubai between December and March and the high temperature throughout the year since that makes providing water to rural and isolated zones essential. The proposed system uses voltage regulator to maintain stable DC voltage from the solar power system, battery bank to store the voltage from solar PV panels, three-phase rectifier to convert the AC voltage from wind power system to DC, three-phase step-down transformers to reduce the AC voltage of the wind turbine and diesel generator, and DC electric motor for water pumping output. The system used neural network for solar irradiance forecasting over an interval of 10 years (from 2009 to 2019). The proposed system will be demonstrated using Simulink to show the stability and performance under different weather conditions.
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Nagraju, B., J. Suresh, B. Mohan Kumar, G. Suresh, G. Ravi Varma, M. Murali, K. SowjanKumar, G. V. K. Murthy, and K. Srinivasa Rao. "Integration of Renewable Energy Generating Sources with Micro-Grid." International Journal of Innovative Research in Engineering & Management 9, no. 2 (2022): 628–34. http://dx.doi.org/10.55524/ijirem.2022.9.2.99.
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This paper shows the control of microgrids at isolated sites powered by hybrid wind and solar energy sources. The machine used for wind energy conversion is a double fed induction generator (DFIG) and the battery bank is connected to a common DC bus from them. Photovoltaic (PV) arrays are used to convert solar energy. Solar energy is consumed in a cost-effective manner with a DC-DC boost converter on DFIG's common DC bus. The voltage and frequency are adjusted by the indirect vector control of the line-side converter with drooping characteristics. It changes the frequency reference based on the energy level of the battery, slowing the overcharging or discharging of the battery. This system can be operated without wind power. Control algorithms for wind and solar systems include maximum power point tracking (MPPT). This system is designed for fully automated operation, taking into account all the actual conditions of the system also has external power support to charge the battery without additional requirements. The simulation model of the system is developed in the MATLAB environment, and the simulation results are displayed under various conditions. wind or sun impermeable, unbalanced load is equally non-linear, low battery charge state. Finally, the prototype of the system is implemented using a 5kW photovoltaic array simulator and a 3.7kW wound rotor asynchronous machine to generate experimental results to validate the theoretical model and design.
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Xie, Xing-Huan, Xin Fu, Xing-Yu Yan, Wen-Fang Peng, and Li-Xin Kang. "A Broad-Specificity Chitinase from Penicillium oxalicum k10 Exhibits Antifungal Activity and Biodegradation Properties of Chitin." Marine Drugs 19, no. 7 (June 23, 2021): 356. http://dx.doi.org/10.3390/md19070356.
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Penicillium oxalicum k10 isolated from soil revealed the hydrolyzing ability of shrimp chitin and antifungal activity against Sclerotinia sclerotiorum. The k10 chitinase was produced from a powder chitin-containing medium and purified by ammonium sulfate precipitation and column chromatography. The purified chitinase showed maximal activity toward colloidal chitin at pH 5 and 40 °C. The enzymatic activity was enhanced by potassium and zinc, and it was inhibited by silver, iron, and copper. The chitinase could convert colloidal chitin to N-acetylglucosamine (GlcNAc), (GlcNAc)2, and (GlcNAc)3, showing that this enzyme had endocleavage and exocleavage activities. In addition, the chitinase prevented the mycelial growth of the phytopathogenic fungi S. sclerotiorum and Mucor circinelloides. These results indicate that k10 is a potential candidate for producing chitinase that could be useful for generating chitooligosaccharides from chitinous waste and functions as a fungicide.
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Gülkaç, Vildan. "The New Approximate Analytic Solution for Oxygen Diffusion Problem with Time-Fractional Derivative." Mathematical Problems in Engineering 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/8409839.
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Oxygen diffusion into the cells with simultaneous absorption is an important problem and it is of great importance in medical applications. The problem is mathematically formulated in two different stages. At the first stage, the stable case having no oxygen transition in the isolated cell is investigated, whereas at the second stage the moving boundary problem of oxygen absorbed by the tissues in the cell is investigated. In oxygen diffusion problem, a moving boundary is essential feature of the problem. This paper extends a homotopy perturbation method with time-fractional derivatives to obtain solution for oxygen diffusion problem. The method used in dealing with the solution is considered as a power series expansion that rapidly converges to the nonlinear problem. The new approximate analytical process is based on two-iterative levels. The modified method allows approximate solutions in the form of convergent series with simply computable components.
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Bucci, Frédéric, Michael Benzaquen, Fabrizio Lillo, and Jean-Philippe Bouchaud. "Slow Decay of Impact in Equity Markets: Insights from the ANcerno Database." Market Microstructure and Liquidity 04, no. 03n04 (September 2018): 1950006. http://dx.doi.org/10.1142/s2382626619500060.
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We present an empirical study of price reversion after the executed metaorders. We use a dataset with more than 8 million metaorders executed by institutional investors in the US equity market. We show that relaxation takes place as soon as the metaorder ends: while at the end of the same day, it is on average [Formula: see text] of the peak impact, the decay continues for the next few days, following a power-law function at short-time scales, and converges to a non-zero asymptotic value at long-time scales ([Formula: see text] days) equal to [Formula: see text] of the impact at the end of the first day, that is [Formula: see text] of peak impact. Due to a significant, multiday correlation of the sign of executed metaorders, a careful deconvolution of the observed impact must be performed to extract the estimate of the impact decay of isolated metaorders.
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Jiayu, Liu, Xia Xiaomao, and Song Yuxi. "Turning Knife Health Monitoring Based on Vibration Signal with Machine Learning Algorithms." Journal of Physics: Conference Series 2281, no. 1 (June 1, 2022): 012021. http://dx.doi.org/10.1088/1742-6596/2281/1/012021.
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Abstract The wear of the turning tool has a great impact on product quality. With the development of sensor technology and increasing computing power, more and more research focuses on online monitoring and prediction of tool condition using machine learning methods. Nevertheless, most research has been conducted in laboratories, making it difficult to apply the results to the shop floor under complex production conditions. The research is based on vibration data measured in a real production environment of a turning machine. Machine learning models such as Random Forest, XGBoost, etc. were trained to predict the wear condition of the turning tool after features were extracted using digital signal processing techniques such as wavelet decomposition and empirical mode decomposition. A moving average-based method was proposed to convert the binary classification results into the probability of tool failure. On a real manufacturing data set, the online real-time monitoring is realized with an accuracy of 93.8%. It proves to be a good approach for managing spare parts in a real-time industrial environment with limited and isolated data sources.
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Zhang, Yue, and Ruixing Li. "A Study of Intermediate for Synthesis of Cs0.3WO3 with Near-Infrared Photothermal Response." Energies 15, no. 22 (November 15, 2022): 8542. http://dx.doi.org/10.3390/en15228542.
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Nanoscale tungsten bronze can convert near-infrared light into thermal energy. For a chemical synthesis, intermediate products and processes are potentially positive or negative to an end product. In this study, (NH4)2SO4 was added into the hydrothermal system of WO3, CsCl, CH3CH2CHO, and NH3·H2O to increase the Cs/W ratio in solution. An intermediate, Cs1.1W1.65O5.5, was isolated. Subsequently, it was confirmed via a kinetics experiment conducted for different times. The results of the NH3·H2O and NH4COOCH3 system indicate there are two influence factors that influence the formation of Cs1.1W1.65O5.5: the leaching out of W and imine reactions. A low leaching out rate induces a high Cs/W ratio and low-concentration W in solution, leading to the formation of Cs1.1W1.65O5.5. The imine reaction decreasing CH3CH2CHO restrains the reduction in Cs1.1W1.65O5.5. The increase in CH3CH2COO− with the reduction reaction results in both the micron-size sticks and nano-size equiaxial particles in powder.
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Purwanti, Endah, and Sarah Dampang. "Pengaruh Perbedaan Kondisi Hidrolisis Terhadap Hasil Isolasi Nanokristalin Selulosa Dari Bonggol Jagung." Indo. J. Chem. Res. 5, no. 1 (July 31, 2017): 12–16. http://dx.doi.org/10.30598//ijcr.2017.5-end.
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Cellulose is one of the largest components in corncobs. Cellulose was obtained from corncob in this research that has a yield of 19.6% of 20 grams of corncob powder. The isolated cellulose was characterized by using FTIR and SEM. Cellulose has crystalline chain and insoluble in water or organic solvents. The molecular chain of cellulose is linear and has intra- and inter-molecular hydrogen bonds. One way for cellulose to be easy in the treatment of applications, is to convert microcrystalline cellulose into nanocrystalline cellulose. Nanocrystalline cellulose can be obtained by several methods, one of them by acid hydrolysis. Hydrolysis of cellulose by using sulfuric acid produces nanocrystalline cellulose. Nanocrystalline cellulose can be characterized by using TEM and PSA analysis. CNC 60 has a particle size distribution with a diameter range of 14.3 nm - 45.0 nm and an average diameter of 17.4 nm. Whereas cellulose with CNC 90 has a smaller particle size distribution with a diameter range of 10.0 nm - 17.1 nm and an average diameter of 11.9 nm.
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Mahdisoozani, Hojat, Mehrdad Mohsenizadeh, Mehdi Bahiraei, Alibakhsh Kasaeian, Armin Daneshvar, Marjan Goodarzi, and Mohammad Reza Safaei. "Performance Enhancement of Internal Combustion Engines through Vibration Control: State of the Art and Challenges." Applied Sciences 9, no. 3 (January 25, 2019): 406. http://dx.doi.org/10.3390/app9030406.
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Internal combustion engines (ICEs) are the primary source of power generation in today’s driving vehicles. They convert the chemical energy of the fuel into the mechanical energy which is used to drive the vehicle. In this process of energy conversion, several parameters cause the engine to vibrate, which significantly deteriorate the efficiency and service life of the engine. The present study aims to gather all the recent works conducted to reduce and isolate engine vibration, before transmitting to other vehicle parts such as drive shafts and chassis. For this purpose, a background history of the ICEs, as well as the parameters associated with their vibration, will be introduced. The body of the paper is divided into three main parts: First, a brief summary of the vibration theory in fault detection of ICEs is provided. Then, vibration reduction using various mechanisms and engine modifications is reviewed. Next, the effect of using different biofuels and fuel additives, such as alcohols and hydrogen, is discussed. Finally, the paper ends with a conclusion, summarizing the most recent methods and approaches that studied the vibration and noise in the ICEs.
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Yuan, Yan. "Casting an ‘Outsider’ in the ritual centre: Two decades of performances of ‘Rural Migrants’ in CCTV’s Spring Festival Gala." Global Media and China 2, no. 2 (May 29, 2017): 169–82. http://dx.doi.org/10.1177/2059436417707325.
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Recent years have seen the rise of the ‘processual approach’ in media ritual studies, which focuses on the making of media rituals through various ‘ritualised actions’ rather than assuming them as isolated events distinctive to ordinary broadcasting. This article advances this line of argument by shedding light on a previously less-discussed form of ritualised action: the ritualised casting. It examines how the character of ‘rural migrant’ has been staged in the 28-year history of China Central Television’s Spring Festival Gala and how the casting of this ‘social outsider’ served as a dynamical strategy in the process of ritualisation of the Gala. The case study demonstrates a persistently central position of the image of ‘rural migrants’ in the Gala in the past 21 years, yet the scripting of this ritual subject varied as the agendas and crises of ritualisation shifted. This ritualised casting not only delivered a self-replicating effect that made the success of the Gala as natural and desired, but also, it exhibited a power to converge the media’s categories with other social categories, which further legitimised the ritual authority of the Gala as a mediated centre in the festival space of the Chinese New Year.
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Duputel, Zacharie, Michel Cara, Luis Rivera, and Georges Herquel. "Improving the analysis and inversion of multimode Rayleigh-wave dispersion by using group-delay time information observed on arrays of high-frequency sensors." GEOPHYSICS 75, no. 2 (March 2010): R13—R20. http://dx.doi.org/10.1190/1.3341172.
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Near-surface shear-velocity structure can be inferred from multimode dispersion data. Several methods have been developed to isolate the different modes from seismic signals observed on linear arrays of sensors. Most techniques analyze the wavefield through a frequency-wavenumber [Formula: see text] transform, paying little attention to group-delay-time information. Moreover, classical analyses are generally restricted to fundamental-mode dispersion, limiting the resolution power at depth. We have overcome the limitations of classical [Formula: see text] analysis by using a wavefield representation in the group-velocity/phase-velocity [Formula: see text] domain. We have then set up a nonlinear inversion procedure, easily tractable on a common field computer, to constrain the 1D vertical profile of shear velocities. Applications to synthetic data and to a set of actual records show that [Formula: see text] diagrams greatly help to separate dispersion information between different modes, even when they are not detectable on usual [Formula: see text] diagrams. Tests on synthetic and actual data confirm that the inversion procedure quickly converges to the expected model.
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Biswas, Mohua, Shuvra Prokash Biswas, Md Rabiul Islam, Md Ashib Rahman, Kashem M. Muttaqi, and S. M. Muyeen. "A New Transformer-Less Single-Phase Photovoltaic Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems." Energies 15, no. 22 (November 10, 2022): 8398. http://dx.doi.org/10.3390/en15228398.
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Photovoltaic (PV) energy systems have found diverse applications in fulfilling the increasing energy demand worldwide. Transformer-less PV inverters convert the DC energy from PV systems to AC energy and deliver it to the grid through a non-isolated connection. This paper proposes a new transformer-less grid-connected PV inverter. A closed-loop control scheme is presented for the proposed transformer-less inverter to connect it with the power grid. The proposed transformer-less inverter reduces extra leakage current and holds the common-mode voltage at a constant point. To eliminate extra leakage current, as well as achieve constant common-mode voltage, a midpoint clamping method is utilized to operate the inverter. The proposed transformer-less inverter is formed of seven insulated gate bipolar transistors (IGBTs) employing a unipolar sinusoidal pulse width modulation (SPWM) technique for switching purposes. An LCL filter is employed to reshape the two-level inverter output voltage and current to obtain closer sinusoidal waveforms. The output voltage and current total harmonic distortion (THD) of the proposed transformer-less inverter were found to be 1.25% and 0.94%, respectively, in the grid-connected mode. The leakage current elimination mechanism with the proposed transformer-less inverter is deeply analyzed in this paper. The performances of the proposed transformer-less inverter were evaluated with MATLAB/Simulink simulation and validated in a laboratory scale experiment.
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GUIVARC’H, Y., and EMILE LE PAGE. "On spectral properties of a family of transfer operators and convergence to stable laws for affine random walks." Ergodic Theory and Dynamical Systems 28, no. 2 (April 2008): 423–46. http://dx.doi.org/10.1017/s0143385707001010.
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AbstractWe consider a random walk on the affine group of the real line, we denote by P the corresponding Markov operator on $\mathbb {R}$, and we study the Birkhoff sums associated with its trajectories. We show that, depending on the parameters of the random walk, the normalized Birkhoff sums converge in law to a stable law of exponent α∈ ]0,2[ or to a normal law. The corresponding analysis is based on the spectral properties of two families of associated transfer operators Pt,Tt. The operator Pt is a Fourier operator and is considered here as a perturbation of the Markov operator P=P0 of the random walk. The operator Tt is related to Pt by a symmetry of Heisenberg type and is also considered as a perturbation of the Markov operator T0=T. We prove that these operators have an isolated dominant eigenvalue which has an asymptotic expansion involving fractional powers of t. The parameters of this expansion have simple expressions in terms of tails and moments of the stationary measures of P and T.
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Doan, Chien Thang, Thi Ngoc Tran, and San-Lang Wang. "Production of Thermophilic Chitinase by Paenibacillus sp. TKU052 by Bioprocessing of Chitinous Fishery Wastes and Its Application in N-acetyl-D-glucosamine Production." Polymers 13, no. 18 (September 9, 2021): 3048. http://dx.doi.org/10.3390/polym13183048.
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The bioprocessing of chitinous fishery wastes (CFWs) to chitinases through fermentation approaches has gained importance owing to its great benefits in reducing the enzyme production cost, and utilizing chitin waste. In this work, our study of the chitinase production of Paenibacillus sp. TKU052 in the presence of different kinds of CFWs revealed a preference for demineralized crab shells powder (deCSP); furthermore, a 72 kDa chitinase was isolated from the 0.5% deCSP-containing medium. The Paenibacillus sp. TKU052 chitinase displayed maximum activity at 70 °C and pH 4–5, while Zn2+, Fe3+, Triton X-100, Tween 40, and SDS exerted a negative effect on its activity, whereas Mn2+ and 2-mercaptoethanol were found to potentially enhance the activity. Among various kinds of polysaccharide, Paenibacillus sp. TKU052 chitinase exhibited the best catalytic activity on colloidal chitin (CC) with Km = 9.75 mg/mL and Vmax = 2.43 μmol/min. The assessment of the hydrolysis of CC and N-acetyl chitooligosaccharides revealed that Paenibacillus sp. TKU052 chitinase possesses multiple catalytic functions, including exochitinase, endochitinase, and N-acetyl-β-D-glucosaminidase activities. Finally, the combination of Paenibacillus sp. TKU052 chitinase and Streptomyces speibonae TKU048 N-acetyl-β-D-glucosaminidase could efficiently convert CC to N-acetyl-D-glucosamine (GlcNAc) with a production yield of 94.35–98.60% in 12–24 h.
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Sun, Chein-Chung, Chun-Hung Chou, Yu-Liang Lin, and Yu-Hua Huang. "A Cost-Effective Passive/Active Hybrid Equalizer Circuit Design." Energies 15, no. 6 (March 9, 2022): 2000. http://dx.doi.org/10.3390/en15062000.
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This paper proposes a novel hybrid equalizer circuit (HEC) for a battery management system (BMS) to implement the passive HEC (P-HEC), active HEC (A-HEC), or active/passive (AP-HEC) with the same equalizer circuit architecture. The advantages of an HEC are that it is simple, cost-effective, highly energy efficient, and fail safe. The P-HEC can further use a cooling fan or heater instead of a conventional resistor as a power dissipation element to convert the energy of the waste heat generated by the resistor to adjust the battery temperature. Even if the P-HEC uses the resistor to consume energy as in conventional methods, the P-HEC still dramatically improves the component lifetime and reliability of the BMS because the waste heat generated by the equalizer resistor is outside of the BMS board. Three significant advantages of an A-HEC are its (1) low cost, (2) small volume, and (3) higher energy efficiency than the conventional active equalizer circuits (AECs). In the HEC design, the MOSFETs of the switch array do not need high-speed switching to transfer energy as conventional AECs with DC/DC converter architecture because the A-HEC uses an isolated battery charger to charge the string cell. Therefore, the switch array is equal to a cell selector with a simple ON/OFF function. In summary, the HEC provides a small volume, cost-effective, high efficiency, and fail-safe equalizer circuit design to satisfy cell balancing demands for all kinds of electric vehicles (EVs) and energy storage systems (ESSs).
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N, Kanagaraj, Morteza Mollajafari, Farzam Mohammadiazar, Ehsan Akbari, Ebrahim Sheykhi, and Hicham Chaoui. "A New Voltage-Multiplier-Based Power Converter Configuration Suitable for Renewable Energy Sources and Sustainability Applications." Sustainability 14, no. 24 (December 13, 2022): 16698. http://dx.doi.org/10.3390/su142416698.
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The sustainability of new-generation energy sources has become one of the most critical challenges in recent years as renewable energy sources (RESs) rapidly replace old fossil sources. Integration between RESs and the grid should be completed through power electronics converters and optimized control techniques. RESs have many advantages, such as having increased reliability and sustainability, being environmentally friendly, and having cheaper maintenance costs and more reasonable energy prices. Photovoltaic (PV) panels are among the most popular RESs. A PV array’s generated voltage level is unsuitable for direct load or grid connection and has to be enhanced via a DC-DC boost converter. After that, an inverter should be used to change the generated DC voltage to AC voltage for the grid or loads. In order to reach higher voltage gains, different structures have been proposed in the literature, such as cascaded converters, non-isolated converters (including transformers), and positive- and negative-voltage-lift Luo converters. These converters have some disadvantages, such as including a large number of semiconductor devices and inductors, heavy and bulky structures, and the need for intermediate converters to convert DC to AC voltage and vice versa. Besides the efficiency and high DC voltage gain feature, to achieve more reliability and sustainability and a longer lifetime of the PV source, the current drawn from these sources should be as ripple-free as possible. This study considers all these details by presenting a novel DC-DC power boost converter. The steady-state analysis, simulation, and test results are presented. The most important features of the proposed converter include the lack of need for a transformer, intermediate inverter, rectifier converters, and bulky and heavy components, while still ensuring that high voltage gains and high efficiencies are possible. Simulation results showed that for duty ratios from D = 0.05 to D = 0.15 for the switch S3, the gain of the converter was 22, 35, and 70 times greater than the input voltage, respectively. The desired 200 VDC and 400 VDC voltages for the output nodes were obtained using 12 VDC as the input voltage with and without the switched-capacitor cell, respectively. A limited number of the voltages between −47 and 12 V dropped across the inductors, and a reversed voltage from −12 to −48 V was reported for the power diodes. Additionally, an efficiency close to 96.88% was obtained for the proposed converter. According to the experimental results, a voltage close to 198 VDC was obtained with a 12 VDC input voltage source without using the switched-capacitor cell. A current with a maximum of 7 A was reported for the output diode, and more than 96% efficiency was reported. The results showed that the primary source of the power losses was the semiconductors, and the switching losses made up around 69% and 88% of the total losses for the switches and diodes, respectively. The present topology has three power switches. Two of the switches are activated and deactivated simultaneously. The third switch is activated or deactivated in reverse with the other switches. The results showed that for short-duty ratios such as 0.5 for switches S1 and S2 and 0.35 for switch S3, DC voltage gains close to 35 were obtained theoretically. The generated voltage could be doubled by applying fourth and fifth power switches by making a switched-capacitor-based topology. All of these details are illustrated in this study in detail. The proposed circuit was set up and tested in a laboratory environment. The test results confirm the simulation and theoretical analysis.
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Gunawan, Sulistyo, and I. Setiawan. "Preparation and characterization of RHA based ceramic membrane for gas leak testing in SOFC seals." IOP Conference Series: Earth and Environmental Science 969, no. 1 (January 1, 2022): 012052. http://dx.doi.org/10.1088/1755-1315/969/1/012052.
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Abstract Solid Oxide Fuel Cell (SOFC) systems show great potential in future power generation applications. SOFC has many advantages, including high efficiency, low emission, and flexible modular structure. SOFC is an electrochemical device that converts fuel into electricity directly. If hydrogen gas is used, it will produce electricity and waste products in the form of heat and water vapor. The complete SOFC module system consists of a furnace, cell stack, fuel and oxygen. Several parameters that affect SOFC performance are fuel flow rate, furnace temperature, cell material, and collector current. SOFC consists of anode, electrolyte, cathode, and current collector. These parameters have a correlation with each other in building a SOFC system, resulting in a good cell and optimal output voltage. SOFC based on electrolyte material yttria stabilized zirconia (YSZ) operates at working temperatures between 600 to 1,000°C, so all materials used must be able to withstand these temperatures. In the empirical case to separate each function of the components in the fuel cell, a sealant is needed. The sealant function prevents fuel and oxidant leakage in the stack and electrically isolates the cells in the stack. So the other sealant material requirements are to have thermal and chemical compatibility with other cell components, chemically and physically stable at high temperatures and have good mechanical strength. The composition of the material (RHA, CaO, Al2O3, MgO and BaO) with six formulations (F1-F6) which was determined as a gas leak test specimen through a synthesis process using the ball mill method for 12 hours resulted in a grain variation between 3.808 um – 19.631 um. The production of gas leak test specimens was successfully carried out by molding which was designed to be effective using a material weight of 1.5 grams with a 96% PVA binder as much as 20% by weight. The size of the specimen obtained in the form of a membrane with a thickness of 1-1.1mm. The preparation of the test material can be continued in the next gas leak test process.
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Bliznjuk, Olga, Nataliia Masalitina, Liliia Myronenko, Oksana Zhulinska, Tatyana Denisenko, Serhii Nekrasov, Serhii Stankevych, Oleksandr Bragin, Oleksii Romanov, and Tetiana Romanova. "Determination of rational conditions for oil extraction from oil hydration waste." Eastern-European Journal of Enterprise Technologies 1, no. 6(115) (February 28, 2022): 17–23. http://dx.doi.org/10.15587/1729-4061.2022.251034.
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As a result of oil hydration, waste is formed – phosphatide concentrate, which is a multicomponent system. Valuable components of the concentrate are vegetable oil and phosphatides, the separation of which is an urgent task for the industry. The process of treatment of sunflower phosphatide concentrate with citric acid (hydration) in order to more completely convert non-hydrated forms of phosphatides into hydrated ones and separate the oil from the concentrate was studied. A feature of the work is the study of the dependence of the yield and mass fraction of moisture in the extracted oil on the hydration process parameters. A sample of phosphatide concentrate with non-standard quality indicators according to SOU 15.4-37-212:2004 (CAS 3436-44-0) was studied: the mass fraction of moisture and volatile substances was 4.0 %, the mass fraction of phosphatides was 37.0 %. The concentrate was treated with citric acid solution at a temperature of 45 °C (10 % solution). Rational conditions for concentrate treatment were determined: duration (25 min) and citric acid concentration in relation to the mass of phosphatide concentrate (25 %). Under these conditions, the oil yield was 76.1 %, the mass fraction of moisture in the oil was 18.6 %. The indicators characterizing the suitability of the oil for consumption and its safety for the body are within the limits (acid value 3.7 mg KOH/g, peroxide value 5.1 ½ O mmol/kg) for the first-grade unrefined unwinterized sunflower oil according to DSTU 4492. Such oil can be used for refining, fatty acids and biodiesel production, and after additional purification – for processing into food products. The results of the study make it possible to use resources rationally and predict the yield and quality of the oil isolated from the phosphatide concentrate. The resulting oil can be an affordable raw material for various industries.
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Okezue, Mercy, Daniel Smith, Matthias Zeller, Stephen R. Byrn, Pamela Smith, Susan Bogandowich-Knipp, Dale K. Purcell, and Kari L. Clase. "Crystal structures of salts of bedaquiline." Acta Crystallographica Section C Structural Chemistry 76, no. 11 (October 19, 2020): 1010–23. http://dx.doi.org/10.1107/s2053229620013455.
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Bedaquiline [systematic name: 1-(6-bromo-2-methoxyquinolin-3-yl)-4-(dimethylamino)-2-(naphthalen-1-yl)-1-phenylbutan-2-ol, C32H31BrN2O2] is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). It is marketed in the US as its fumarate salt {systematic name: [4-(6-bromo-2-methoxyquinolin-3-yl)-3-hydroxy-3-(naphthalen-1-yl)-4-phenylbutyl]dimethylazanium 3-carboxyprop-2-enoate, C32H32BrN2O2 +·C4H3O4 −}, and about a dozen other salts of bedaquiline have been described in patent literature, but none have so far been structurally described. In a first communication, we present the crystal structure of bedaquilinium fumarate and of two new benzoate salts, as well as that of a degradation product of the reaction of bedaquilinium fumarate with sodium ethoxide, 3-benzyl-6-bromo-2-methoxyquinoline, C17H14BrNO. The fumarate and benzoate salts both feature cations monoprotonated at the dimethylamino group. The much less basic quinoline N atom remains unprotonated. Both salts feature a 1:1 cation-to-anion ratio, with the fumarate being present as monoanionic hydrofumarate. The conformations of the cations are compared to that of free base bedaquiline and with each other. The flexible backbone of the bedaquiline structure leads to a landscape of conformations with little commonalities between the bedaquiline entities in the various structures. The conformations are distinctively different for the two independent molecules of the free base, the two independent molecules of the hydrofumarate salt, and the one unique cation of the benzoate salt. Packing of the salts is dominated by hydrogen bonding. Hydrogen-bonding motifs, as well as the larger hydrogen-bonded entities within the salts, are quite similar for the salts, despite the vastly differing conformations of the cations, and both the hydrofumarate and the benzoate structure feature chains of hydrogen-bonded anions that are surrounded by and hydrogen bonded to the larger bedaquilinium cations, leading to infinite broad ribbons of anions, cations, and (for the benzoate salt) water molecules. The benzoate salt was isolated in two forms: as a 1.17-hydrate (C32H32BrN2O2 +·C7H5O2 −·1.166H2O), obtained from acetone or propanol solution, with one fully occupied water molecule tightly integrated into the hydrogen-bonding network of anions and cations, and one partially occupied water molecule [refined occupancy 16.6 (7)%], only loosely hydrogen bonded to the quinoline N atom. The second form is an acetonitrile solvate (C32H32BrN2O2 +·C7H5O2 −·0.742CH3CN·H2O), in which the partially occupied water molecule is replaced by a 74.2 (7)%-occupied acetonitrile molecule. The partial occupancy induces disorder for the benzoate phenyl ring. The acetonitrile solvate is unstable in atmosphere and converts into a form not distinguishable by powder XRD from the 1.17-hydrate.
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Pribyl, Barbara, and Greg Horton. "Technology Focus: Reserves Management (December 2022)." Journal of Petroleum Technology 74, no. 12 (December 1, 2022): 42–43. http://dx.doi.org/10.2118/1222-0042-jpt.
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We continue to live in volatile times. While there has been an easing of the global pandemic, geopolitical issues and conflicts have been increasing. There is also ever-increasing pressure to sanction and maintain oil and gas projects in a socially and environmentally sustainable manner. These projects can no longer be considered part of an isolated or independent petroleum sector but as part of the whole resource base of an area, country, or region. There needs to be visibility of the linkages among company vision; national, regional, and global targets; and the project attributes in meeting sustainable development goals and maintaining good governance. Paper SPE 205603 is a good example of a systematic approach to managing oil and gas reserves and resources data that has been assessed using the SPE Petroleum Resources Management System (PRMS). It is important for entities to accurately capture the information gathered during resource evaluation to use for strategic planning and sound resource management. We have been encouraged with the ongoing adaption of PRMS and many of the recommendations of the system, including the use of project-maturity subclasses. We would like to provide a cautionary note that several papers in the 2021–22 cycle highlight the need to ensure that management of resources complies with the requirements of PRMS when they say they do—for example, that when modifications are made to the system, the project still meets the requirements for inclusion in a particular class, such as discovery for contingent resources; and that discovered unrecoverable resources are not contingent resources. Paper SPE 207801 is a case study in trying to apply the principles of sustainable resource management by repurposing oil and gas wells for geothermal production. The paper follows a systems approach to testing the principles of the circular economy (though this term is not used in the paper). A circular economy is a systems approach that enables the resource to maintain its highest value for as long as possible. Critical considerations in implementing circularity are reducing and rethinking resource use and pursuing longevity, renewability, reusability, reparability, replaceability, and upgradability for resources and value-added products. Paper SPE 208483 discusses the challenge of decommissioning oil and gas equipment in Australia. The paper is a comprehensive discussion that highlights the importance of good regulation and the development of visible and robust decommissioning plans by industry titleholders. This important issue will resonate at a global scale and underlines the importance of a lifecycle focus on decommissioning rather than a just-in-time approach, which may not optimize costs or engender safe and environmentally responsible practices. Finally, we encourage you to seek out the additional reading material. Topics include good governance in exploration planning, testing pathways to decarbonization for remote offshore gas fields, an integrated subsurface study, and an example of the complementary use of PRMS and the United Nations Framework Classification. Recommended additional reading at OnePetro: www.onepetro.org. IPTC 21458 The Dusk of the Minimum Economic Field Size in the Digital Era of Exploration Value Creation by Dmitry Surovtsev, Schlumberger, et al. OTC 30941 Pathway to Decarbonization and Maximum Value Recovery for Remote Offshore Gas Fields by Lee Thomas, Intecsea, et al. SPE 205688 Integrated Subsurface Study To Convert Upside Intrabeta Subzone Stakes Into Additional Main Targets in Tunu Gas Field, Mahakam Delta, Indonesia by Dwiki Drajat Gumilar, Pertamina Hulu Mahakam, et al. SPE 207055 The United Nations Framework Classification Concept and the Possibility of Its Application in Azerbaijan by Narmina Garayeva, Baku Higher Oil School, et al.
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Nasir, Bilal Abdullah. "Generating Electricity from Micro-hydro Power Stations to Feed the Isolated Areas of the National Network." Journal of Energy Research and Reviews, September 25, 2021, 17–20. http://dx.doi.org/10.9734/jenrr/2021/v8i430217.
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The construction of small-hydro power stations does not require high technologies, but needs to provide a river or stream water is smooth. Through the establishment of small dams on the stream can control the amount of water necessary to rotate the water turbine, which in turn converts the potential energy of water into kinetic energy. Through the transfer of kinetic energy of rotation of the turbine to the generator can convert this energy into electrical energy. The idea of our plan of research for electrical energy from the power of water using small- hydroelectric plants, which can be built on small rivers, streams, and through the construction of small dams to control the amount of water. Electrical energy derived from small- hydroelectric plants could help feed the electrical loads to areas isolated from the national grid and can be linked with the national grid to add additional electric power.
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Gupta, Swati, and Annapurna Bhargava. "A Novel Isolated AC to DC Power Factor Corrector Rectifier with Higher Switching Frequency." INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 06, no. 04 (April 17, 2022). http://dx.doi.org/10.55041/ijsrem12333.
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The primary aim of this research paper is to design a novel low-cost ac-dc power rectifier for improving power factor and total harmonic distortion with higher switching frequency topology using fewer switches on its secondary side. This modified topology converts ac to dc power maintaining the criteria of international power conversion standards. Due to high currents on the low-voltage side and expensive prices, conventional rectifiers have considerable conduction losses, especially when multiple active devices are used in any form either in series, parallel or in combination to attain high voltage and high power levels. The suggested methodology substitutes traditional three-level converters on the secondary side with only two switches and four diodes while retaining its core converter operation. The simulation is performed in the MATLAB2019b environment. Keywords- Isolated AC-DC rectifier, lossless switching, ZVS and ZCS, solid-state transformer converter.
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Jolhe, Sachin P., Gunwant A. Dhomane, and Minal D. Karalkar. "Design of protection and control scheme for hybrid nanogrid." Protection and Control of Modern Power Systems 6, no. 1 (December 2021). http://dx.doi.org/10.1186/s41601-021-00213-y.
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AbstractNanogrid is “The new ray of hope” for people living in remote isolated locations as well as where power supply reliability is poor. A nanogrid is a small power capacity distribution system with the ability to operate standalone or with a utility grid. It consists of local power production supplying local loads and energy storage systems. In this paper, an innovative inverter design is presented, which converts the power in a single stage. It is superior to the traditional two-stage inverter system and can supply hybrid loads (AC and DC loads) with a single input. System AC and DC bus voltages are regulated under both steady-state and dynamic load variation conditions in the nanogrid. Simulation results are presented which confirm the suitability of the inverter and its control strategy for a hybrid nanogrid system.
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NUGRAHA, HADI WISA, GUNAWAN DJAJAKIRANA, SYAIFUL ANWAR, and DWI ANDREAS SANTOSA. "Producing renewable electric energy through a microbial fuel cell in the rice field." Biodiversitas Journal of Biological Diversity 21, no. 9 (August 18, 2020). http://dx.doi.org/10.13057/biodiv/d210927.
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Abstract. Nugraha HW, Djajakirana G, Anwar S, Santosa DA. 2020. Producing renewable electric energy through a microbial fuel cell in the rice field. Biodiversitas 21: 4139-4146. Microbial Fuel Cell (MFC) is an alternative technology that converts chemical energy into electrical energy using microbes. This study aimed to apply MFC technology in the rice field to produce renewable electricity by utilizing microbes that have been previously isolated. The study was conducted in two experiments. The first experiment was carried out to select MFC prototypes with different in the oxygen circulation system (anode and cathode holes) that capable of producing the highest Voltage. The second experiment was performed to test the selected MFC prototype for electricity production in 12 combination treatments of microbes, organic matter, and fertilization (mixed NPK fertilizer) with three replications on rice cultivation in a greenhouse. The results showed that the best MFC prototype was a prototype that has two holes, each at anode and cathode (MFC 2). The highest electrical Voltage was generated by the treatment with microbes and organic matter, without fertilizer. The treatments produced the highest electrical current was the addition of microbes, organic matter, without and with 50% fertilizer. The highest power density was generated by the treatment with microbes and organic matter, without fertilization. The addition of ex-situ isolated microbes significantly increased the production of electricity.
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"A LIBERAL FEMINIST APPROACH TO CHARLOTTE PERKINS GILMAN’S THE YELLOW WALLPAPER." Ulakbilge Dergisi 9, no. 65 (October 30, 2021). http://dx.doi.org/10.7816/ulakbilge-09-65-02.
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Patriarchal society gives legal rights and economic power to men only so that women are subject to men and imprisoned in private sphere. When women who are given only the role of a wife and mother begin to demand freedom and legal rights, the basis of feminism appears. This study applies liberal feminist approach to Charlotte Perkins Gilman’s The Yellow Wallpaper (1892) in order to analyse the gender roles in terms of patriarchal ideology of separate spheres. After giving birth to a baby, the narrator is diagnosed with hysteria by her husband John who is a physician. She is also prescribed a ‘rest cure’ for three months in the attic of an isolated house. The ‘rest cure’ causes her obsession with the yellow wallpaper and slowly drives her mad due to the limitation of thinking and of raising the consciousness of female in private sphere. To be imprisoned in a room may have enormous risks of disappointment, madness, and suicide. In order to limit a woman’s participation in the intellectual and public sphere, masculine science of nineteenth century’s patriarchal society converts ‘an angel in the house’ into ‘the madwoman in the attic’ under the name of ‘rest cure’. Gilman suggests that a woman can only free herself if her financial conditions are radically changed through finally installing a dialectical movement between private sphere and public sphere.
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Inbasakaran, S., Mahesh K, and Lithesh J. "Design of Single Inductor and Two Output DC - DC Converter." International Journal of Scientific Research in Science, Engineering and Technology, November 5, 2020, 54–59. http://dx.doi.org/10.32628/ijsrset207611.
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<p>A DC-DC converter is used to convert from one DC voltage level to another DC voltage level. The output voltage may be increased or decreased when compare to the input voltage based on the circuit topology. DC – DC converters are mainly used as a regulated and isolated power supplies in many applications. Regulated dc power supplies are needed for most analog and digital electronic systems. Most power supplies are designed to meet some or all of the following requirements:</p> <p><strong>Regulated output: </strong>The output voltage must be kept constant with respect to the change in output loading.</p> <p><strong>Isolation: </strong>The output may be required to be electrically isolated from the input.</p> <p>In addition to these requirements, common goals are to reduce power supply size and weight and improve their efficiency. A few applications of DC-DC converters are where 5V DC on a personal computer motherboard must be stepped down to 3V, 2V or less for one of the latest CPU chips; where 1.5V from a single cell must be stepped up to 5V or more, to operate electronic circuitry. The main focus in this paper is to generate dc voltage from a one level to other level with minimum loss. The need for such converters has risen due to the fact that transformers are unable to function on dc.</p>
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Inbasakaran, S., Mahesh K, and Lithesh J. "Design of Single Inductor and Two Output DC - DC Converter." International Journal of Scientific Research in Science, Engineering and Technology, November 5, 2020, 54–59. http://dx.doi.org/10.32628/ijsrset207611.
Full textAbstract:
<p>A DC-DC converter is used to convert from one DC voltage level to another DC voltage level. The output voltage may be increased or decreased when compare to the input voltage based on the circuit topology. DC – DC converters are mainly used as a regulated and isolated power supplies in many applications. Regulated dc power supplies are needed for most analog and digital electronic systems. Most power supplies are designed to meet some or all of the following requirements:</p> <p><strong>Regulated output: </strong>The output voltage must be kept constant with respect to the change in output loading.</p> <p><strong>Isolation: </strong>The output may be required to be electrically isolated from the input.</p> <p>In addition to these requirements, common goals are to reduce power supply size and weight and improve their efficiency. A few applications of DC-DC converters are where 5V DC on a personal computer motherboard must be stepped down to 3V, 2V or less for one of the latest CPU chips; where 1.5V from a single cell must be stepped up to 5V or more, to operate electronic circuitry. The main focus in this paper is to generate dc voltage from a one level to other level with minimum loss. The need for such converters has risen due to the fact that transformers are unable to function on dc.</p>
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Dr. Veeru, P. Prabhakar, E. Renuka, Md. Amzad, M. Srilekha, and B. Sandhya. "Design and Control of Micro-Grid fed by Renewable Energy Generating Sources." International Journal of Advanced Research in Science, Communication and Technology, April 30, 2021, 10–15. http://dx.doi.org/10.48175/ijetir-6238.
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This paper presents a control of a micro-grid at an isolated location fed from wind and solar based hybrid energy sources. The machine used for wind energy conversion is doubly fed induction generator (DFIG) and a battery bank is connected to a common DC bus of them. A solar photovoltaic (PV) array is used to convert solar power, which is evacuated at the common DC bus of DFIG using a DC-DC boost converter in a cost effective way. The voltage and frequency are controlled through an indirect vector control of the line side converter, which is incorporated with droop characteristics. It alters the frequency set point based on the energy level of the battery, which slows down over charging or discharging of the battery. The system is also able to work when wind power source is unavailable. Both wind and solar energy blocks, have maximum power point tracking (MPPT) in their control algorithm. The system is designed for complete automatic operation taking consideration of all the practical conditions. The system is also provided with a provision of external power support for the battery charging without any additional requirement. A simulation model of system is developed in Matlab environment and simulation results are presented for various conditions e.g. unviability of wind or solar energies, unbalanced and nonlinear loads, low state of charge of the battery. Finally a prototype of the system is implemented using a 5 kW solar PV array simulator and a 3.7 kW wound rotor induction machine and experimental results are produced to reaffirm the theoretical model and design.