Maximum Power Generation Research Articles

Design optimization and experimental evaluation of photovoltaic double skin facade

This study proposed the introduction of a photovoltaic double skin façade (PV-DSF) as a way to economically and easily improve the performance of building envelopes. This system has been designed to be installed not only in new buildings but also in remodeling or renovation projects of existing buildings even in a state where occupants are present inside. For the PV-DSF system suggested, this study aimed to perform experimental evaluation of 1) the optimal operation method to maximize electric energy production of the PV vent window and to reduce the heating and cooling energy consumption of buildings and 2) the thermal behavior and energy performance of the building when the proposed PV-DSF is applied.Analysis results using simulation have shown that the monthly optimal operating angles of the PV vent window to minimize heating and cooling energy demand were the same as the operating angles to maximize power generation. It has also been proven through experiments that the proper operation of the PV vent window can significantly reduce the energy demand of buildings. In particular, the difference between the DSF and outdoor temperatures was 12 °C in winter, showing that it is possible to achieve a significant reduction of heating energy demand. Lastly, when the PV-DSF was applied, air and wall temperatures were decreased by 0.5 °C and 2 °C in summer, respectively, and cooling energy consumption was also at least 10% reduced on average.

The relationship between supination resistance and the kinetics and kinematics of the foot and ankle during gait

BackgroundClinical tests of foot posture and mobility are not strongly related to the dynamic kinematics of the foot during gait. These measures may be more directly related to foot and ankle kinetics. The supination resistance test (SRT) is a clinical test that may more directly measure forces acting on the weightbearing foot to provide clinicians with insight about the loading of foot structures. Research QuestionWhat is the relationship between the SRT in relaxed calcaneal stance and in single-leg-stance and the kinetics and kinematics of the foot and ankle during gait? Methods10 healthy adults between the ages of 18 and 65 were recruited to participate in this study. Three-dimensional motion analysis was performed using the Oxford Foot Model during gait. The results of the SRT were compared with peak midfoot and ankle joint moments, power generation and absorption, joint angles, and peak angular velocities and accelerations. Correlation coefficients were calculated to assess the strength of relationships between these variables and the SRT. ResultsThe SRT demonstrated significant relationships with several variables. In relaxed calcaneal stance, the SRT was inversely related to maximum midfoot pronation moments (r = −0.51), maximum midfoot plantarflexion moments (rho = −0.71), and peak midfoot power generation (r = −0.61). In single-leg-stance, the SRT was significantly related to maximum midfoot plantarflexion moments (rho = −0.55) and peak midfoot power generation (r = −0.47). SignificanceThe SRT is significantly associated to several kinetic variables that quantify midfoot loading during gait. Interventions that decrease supination resistance may have the potential to increase midfoot power generation.

Optimisation in operating strategies for concentrating solar power plants

This research paper emanates from a directive of Eskom, South Africa’s power utility, to acquire a more full understanding of the technical, financial, and operational aspects of running a plant that is built on concentrating solar central receiver technology. Eskom owns the supply chain of electricity, this includes generation, transmission, distribution and management of the electric grid. The power utility identified the need to understand the operating capabilities of such plants within the South African electric grid. Therefore, to demonstrate the role and value Concentrated Solar Power (CSP) with storage offers to the electric grid, an array of operating strategies was identified during the design phase of Eskom’s Solar-1 project. These operating strategies explored in this paper are; Maximising Power Generation, Maximise Plant Revenue, Minimise Energy Dumping and Optimise Electric Grid (base load, peaking and auxiliary services). A Typical Meteorological Year (TMY) data set for the case study plant situated in Upington, South Africa is used to obtain the annual performance of the plant. In the ‘Maximise Power Generation’ operating strategy the developed model increases the power block efficiency by 1.8% utilising part-load operational optimisation instead of running the turbine at full load until depletion of the hot storage tank. This is achieved by reducing the total annual turbine stops by 50% to only 176 stops. The thermal energy saved from start-up of the power block is utilised for power generation instead. Results from the ‘Base Load’ operating strategy reduces the turbine stops by 85% to only 52 stops annually. Therefore, increasing the turbine online hours to 94.5%. The results from the ‘Minimise Energy Dumping’ operating strategy shows that it is possible to reduce energy dumping from 4.0% to 2.7% by effectively optimising the dispatch from the hot storage tank at selected times and increasing the power block output to 110%. As a result, an additional 7.4% of electric energy is generated from this saving. Under the ‘Optimise Electric Grid’ operating strategies, the complementary services of CSP to other non-dispatchable power generation technologies such as wind and photovoltaics are investigated. CSP with storage has the potential to increase the utilisation factor of distribution substations in grid constrained areas within the grid. This opportunity greatly increases the market of CSP and emphasises the value of thermal storage. However, plant design optimisation is required for this operating strategy as it greatly affects the plant performance of the case study plant. Although CSP with storage demonstrates continuous reliable power delivery to the electric grid it also provides complementary services to non-dispatchable generating technologies.

Power dispatching tracking control of wind turbine considering maximum and limited power generation below rated wind speed

Wind turbines should respond to power dispatching of power grid at all times. According to this demand, this paper puts forward a set of feasible power control strategies below rated wind speed. Firstly, the operation state of wind turbine is divided into two working modes: maximum power generation and wind power curtailment generation. Different control strategies are adopted in different working conditions. Under the mode of maximum power generation, the model predictive control (MPC) algorithm is used to give a torque compensation gain. The MPC controller not only improves the utilization efficiency of wind energy, but also reduces the mechanical load. Under the mode of wind curtailment, a hybrid tracking control strategy of giving priority to torque control than pitch regulation is adopted. It reduces the frequency and amplitude of the pitch mechanism greatly. By comparing the simulation results under various wind speeds, it is found that the proposed power control strategy can adapt to different power dispatching scenes, and can respond to power dispatching with greater performance. It is very significant for the improvement of wind power generation system.

Economic optimization of stacked microbial fuel cells to maximize power generation and treatment of wastewater with minimal operating costs

This study proposes an optimization-based strategy to select the best electrical stacking configuration of microbial fuel cells to achieve the highest power output and chemical oxygen demand removal under the lowest operating costs. Three similar wastewater-fed continuous flow microbial fuel cells are electrically connected in four different modes and concentrations of fuel substrate and buffer in anolyte, as main operating cost items, are optimized using two-level factorial design with the dual objective of maximizing power density and minimizing operating costs. In series connection the lowest ratio of operating costs to maximum power $0.048.mW−1.d−1 is achieved that is comparable to the ratio of $0.046.mW−1.d−1 for an individual unit as control. Optimization reduces operating costs 61% with only 37% reduction in maximum power compared to maximum attainable power. At the optimized concentrations, the lowest operating costs to chemical oxygen demand removal ratio $2.01.COD−1 is observed in series connection. This suggests that the cheapest way to stack microbial fuel cells to gain the highest power output and chemical oxygen demand removal is serial electrical connection.

Expert Control Systems for Maximum Power Point Tracking in a Wind Turbine with PMSG: State of the Art

Wind power is a renewable energy source that has been developed in recent years. Large turbines are increasingly seen. The advantage of generating electrical power in this way is that it can be connected to the grid, making it an economical and easily available source of energy. The fundamental problem of a wind turbine is the randomness in a wide range of wind speeds that determine the electrical energy generated, as well as abrupt changes in wind speed that make the system unstable and unsafe. A conventional control system based on a mathematical model is effective with moderate disturbances, but slow with very large oscillations such as those produced by turbulence. To solve this problem, expert control systems (ECS) are proposed, which are based on human experience and an adequate management of stored information of each of its variables, providing a way to determine solutions. This revision of recent years, mentions the expert systems developed to obtain the point of maximum power generation in a wind turbine with permanent magnet synchronous generator (PMSG) and, therefore, offers a control solution that adapts to the specifications of any wind turbine.

Thermodynamic analyses and optimization of a novel CCHP system integrated organic Rankine cycle and solar thermal utilization

Combined cooling, heating and power systems (CCHP) have received wide attention recently because of its prominent role in energy utilization. It could both decrease the energy consumption and improve the overall energy efficiency. In this paper, a novel coupled CCHP system was proposed which is composed of a conventional CCHP system, a solar thermal utilization (ST) subsystem and an organic Rankine cycle (ORC) subsystem. The CCHP-ST-ORC system has been evaluated thermodynamically, and compared with CCHP system and CCHP-ST system, which is based on the GICE (rated internal combustion engine capacity) of 100 kW. Further, through the parametric study for CCHP-ST-ORC system, the effect of several operating parameters on the system thermodynamic performance is explored. Finally, a new operation strategy for CCHP-ST-ORC system was proposed and adopted in a residential building, which presents a better thermodynamic economy than CCHP-ST system. As the result, CCHP-ST-ORC system could generate an additional electricity of 5.1 kW compared with other two systems, which is at the expense of 39.3 kW heat. Further, it could expand the maximum power generation to 108 kW. The case study shows that the primary energy ratio of CCHP-ST-ORC system is 60.2% that is much higher than the 37.6% of CCHP-ST system. The results also indicate that the CCHP-ST-ORC system consumes 9.81 × 104 m3/year of natural gas, with a 12.4% reduction in energy consumption than CCHP-ST system. Therefore, these findings can promote the sustainable development of new energy utilization models, especially the coupling CCHP system.

Parallel general purpose multiobjective optimization framework with application to electron beam dynamics

Particle accelerators are invaluable tools for research in the basic and applied sciences, such as materials science, chemistry, the biosciences, particle physics, nuclear physics and medicine. The design, commissioning, and operation of accelerator facilities is a nontrivial task, due to the large number of control parameters and the complex interplay of several conflicting design goals. The Argonne Wakefield Accelerator facility has some unique challenges resulting from its purpose to carry out advanced accelerator R Individual experiments often have challenging beam requirements, and the physical configuration of the beam lines is often changed to accommodate the variety of supported experiments. The need for rapid deployment of different operational settings further complicates the optimization work that must be done for multiple constraints and challenging operational regimes. One example of this is an independently staged two-beam acceleration experiment which requires the construction of an additional beam line (this is now in progress). The high charge drive beam, well into the space charge regime, must be threaded through small aperture (17.6 mm) decelerating structures. In addition, the bunch length must be sufficiently short to maximize power generation in the decelerator. We propose to tackle this problem by means of multiobjective optimization algorithms which also facilitate a parallel deployment. In order to compute solutions in a meaningful time frame, a fast and scalable software framework is required. In this paper, we present a general-purpose framework for simulation-based multiobjective optimization methods that allows the automatic investigation of optimal sets of machine parameters. Using evolutionary algorithms as the optimizer and opal as the forward solver, validation experiments and results of multiobjective optimization problems in the domain of beam dynamics are presented. Optimized solutions for the new high charge drive beam line found by the framework were used to finish the design of a two beam acceleration experiment. The selected solution along with the associated beam parameters is presented.

Stochastic modelling and availability analysis of a critical engineering system

Purpose The purpose of this paper is to present the technique for evaluating the performance of a condensate system of a coal-based thermal power plant situated in the northern part of India. The data which used for system availability evaluation are not precise and are uncertain and, further, collected from concerned power plant history sheets and from discussion through plant personnel. Design/methodology/approach In the proposed model, traditional Markov birth-death process using a probabilistic approach is used to analyze the performance of a complex repairable condensate system of power plant up to a desired degree of accuracy. This approach has been demonstrated by breaking the condensate system into six subsystems arranged in series with two feasible states, namely, working and failed, labeled in a transition diagram and modeled as a Markov process, using Chapman–Kolmogorov equations, which are used for development of a probabilistic stochastic model for availability analysis in a more effecting manner, considering some suitable assumptions. Findings This study of analysis of reliability and availability can help in increasing the plant production and performance. The analysis is done with the help of availability matrices, which are developed using different combinations of failures and repair rates of all subsystems. To achieve the goal of maximum power generation, it is required to run the various subsystem of the concerned system of plant, failure free for a long duration. Therefore, the present approach may be a more powerful analysis tool to access the performance of all subsystems of a condensate system in terms of availability level achieved in availability matrices. The results of present study are found to be highly beneficial to the plant management for making maintenance decisions. Originality/value The present paper suggests a suitable technique for stochastic modeling and availability evaluation of an industrial system using Markovian approach and drawing a transition diagram to represent the operational behavior of the system. The present methodology includes the advantage of the ability to model and develop a more complex industrial system and helps in improving the performance and handling the uncertainties and possibilities of an industrial system.

Solar chimney power plants – Dimension matching for optimum performance

Solar chimney power plants are very large structures with the potential to generate significant amounts of electricity. Plant dimensions such as the collector diameter and chimney height and radius are important in determining system performance. The objective of this study is to identify the key parameters that drive performance. Performance was assessed in terms of power output and power output per cost. Using a detailed thermodynamic model, the plant power output was predicted for a wide range of design and operational parameters. It was found that the optimum pressure drop ratio depends on the collector and chimney radius, but not on chimney height, ambient temperature or insolation. The dimensions of the main components must be well matched to achieve best performance. Chimney radii of up to 200 m are essential to achieve maximum power generation up to 900 MW. Optimum power output exists for variation of the collector and chimney radius. However, increasing the chimney height always results in increased power generation. The physical phenomena underpinning high-performing configurations were highlighted. Power and efficiency increase with increased plant dimensions, but technological limits exist for the chimney height. A simple but robust cost model was introduced to identify optimum configurations in terms of power output per cost. Different relative costs between collector and chimney the optimum dimensions were selected. It was concluded that several smaller plants with collector radius about 3000 m are advantageous over one larger plant. Taller chimneys are economically beneficial until the specific chimney costs increase more than quadratically with height.

Optimization Techniques and Multi-Objective Analysis in Hybrid Solar-Wind Power Systems for Grid-Connected Supply

Renewable energy has become a vital source for generating electricity, mitigating greenhouse gas emissions, and eliminating the reliance on non-renewable forms of energy. This work highlights on the urgent need for clean, efficient, and resilient energy sources through the development of advanced optimization methods. The hybrid solar-wind systems are meant to maximize power generation. Complexity arises when determining the optimum design, size, functionality, materials, distribution, and mechanism of each system as they are combined to ensure system reliability and optimal outcomes. The development of the new optimization methods (such as genetic algorithms, heuristic approaches, and particle swarm techniques) was generated to overcome the encountered barriers in traditional or classical approaches; such as in iterative techniques and linear programming methods. Additionally, the multi-objective analysis has been involved in various studies where vectors, criteria, and alternatives are applied with respect to the main objectives. However, further research efforts are encouraged to innovatively optimize hybrid solar-wind systems; including the optimization of hybrid solar-wind sizing (HSWS), design, capacity, battery storage, energy distribution systems and techno-economical considerations.

Performance of an air-cathode microbial fuel cell under varied relative humidity conditions in the cathode chamber.

The performance of an air-cathode microbial fuel cell (MFC) with a cap arrangement was significantly affected by humidity conditions in the cathode. An MFC at a relative humidity (RH) of 88% produced a highest cell voltage of 0.42V (600Ω) compared to other operations at 50% (0.34V) and 30% (0.29V) RHs. During polarization analysis, MFC operation at 88% RH produced a maximum power density of 0.377W/m2 (a current density of 1.5A/m2), which was 1.8 and 2.9 times higher than with 50% and 30% RHs, respectively. Cyclic voltammogram analysis revealed a higher reduction current of -0.073 A with 88% RH. Furthermore, no increase in dissolved oxygen concentration in the anode chamber was observed with 88% RH. This result suggests that control of humidity conditions in cathode chamber could maximize power generation from an air-cathode MFC.

Evaluation of Basalt Fibers on Wind Turbine Blades through Finite Element Analysis

Here we use finite element analysis to determine the suitability of basalt fiber as a substitute for E-glass in structural applications, which would improve the cost effectiveness of small wind turbine blades. Five NACA (National Advisory Committee for Aeronautics) profiles were evaluated to select the optimum shape for the wind operation conditions. To obtain the wind load pressure distribution over the blade, a computational aerodynamic analysis by CFD (computational fluid dynamics) was performed based on the blade’s design and operating conditions. Material properties and mechanical tests were carried out to obtain the fiber volume fraction, density, Young’s modulus, shear modulus, and Poisson relation of polymeric matrix composites made using basalt and fiberglass. The obtained wind loads and material properties were used on a FEM (finite element model) analysis to evaluate the structural behavior of the blade under normal and critical operating conditions. Both fibers meet the structural requirements under normal operating conditions. We detected a reduction of 4% in the blade stress when basalt fibers are used instead of glass fibers, and a reduction of 68% in the total deformation for a critical load case of 40 m/s was obtained when using basalt fibers, which met the structural requirements and maximum power generation required for this wind turbine design.

Power and mismatch losses mitigation by a fixed electrical reconfiguration technique for partially shaded photovoltaic arrays

Abstract Partial shading is the most commonly occurring scenario among the modules of the photovoltaic arrays invoking power and mismatch losses. To attenuate these losses, various interconnection topologies for partial shading mitigation have been proposed in the literatures. This paper proposes a fixed electrical reconfiguration technique for the modules that facilitates distribution of the effect of shading in the entire array thereby reducing the losses caused by partial shading. The technique proceeds with renumbering of the modules according to the proposed algorithm followed by electrical rewiring. The entire study has been accomplished by using MATLAB/Simulink environment and field experiment for the arrays of different sizes. The validity of the proposed technique has been critically evaluated using various artificially created shadings and compared with the hitherto known conventional and hybrid topologies. The response of the array having various topologies for every shade condition has been analysed using the characteristics curves and various performance parameters. From the study, it has been found that the proposed technique excels in performance in terms of reducing the number of peaks in the characteristics curves and maximizing power generation during all shade scenarios as compared to other topologies.

ИМПУЛЬСНЫЙ СТАБИЛИЗАТОР НАПРЯЖЕНИЯ С ЦИФРОВЫМ УПРАВЛЕНИЕМ ДЛЯ АВТОНОМНОЙ СИСТЕМЫ ЭЛЕКТРОПИТАНИЯ

Актуальность. Результативность геофизических, геологоразведочных, метеорологических работ и работ по мониторингу окружающей среды во многом определяется системами электропитания испытательной и исследовательской аппаратуры. Специфика таких работ зачастую подразумевает использование полевых автономных систем. Первичными источниками энергии в таких системах, как правило, являются возобновляемые источники энергии, например солнечные батареи, ветро- или гидроэлектроустановки, а вторичными источниками энергии – аккумуляторные батареи. Источники энергии объединяются в систему электропитания посредством импульсных преобразователей энергии, которые выполняют функции по передаче энергии от её источников к потребителям, стабилизации напряжения на выходных шинах, предназначенных для питания потребителей и по повышению энергетической эффективности первичных источников энергии за счёт обеспечения их работы в режиме генерации максимальной мощности. Потребителем электроэнергии таких систем электропитания является сложная и разнородная аппаратура, часто имеющая импульсный характер энергопотребления, что приводит к значительным отклонениям напряжения на выходных шинах системы электропитания от стабильного уровня и, как следствие, к взаимному влиянию отдельных потребителей, приводящему к сбоям в их работе. Таким образом, импульсные преобразователи энергии должны обладать как способностью обеспечения работы первичных источников энергии в режиме генерации максимальной мощности, так и способностью обеспечивать режим стабилизации напряжения на выходных шинах. В режиме генерации максимальной мощности устройство управления импульсным преобразователем обеспечивает перевод и удержание рабочей точки на мощностной характеристике первичного источника в окрестности максимума мощности. В таком устройстве управления реализуется достаточно сложный алгоритм экстремального регулирования и на современном уровне развития техники устройство управления выполняется на основе программируемого цифрового устройства. Решение вопросов по применению этого же программируемого цифрового устройства и для цели управления импульсным преобразователем в режиме стабилизации напряжения на выходных шинах является актуальной задачей, поскольку позволит уменьшить количество элементов в устройстве управления преобразователем, что снизит его собственное энергопотребление и повысит надёжность функционирования. Цель работы: решение теоретических и практических задач по обеспечению цифрового управления импульсным преобразователем в режиме стабилизации выходного напряжения с обеспечением малой длительности переходных процессов, вызванных приращениями тока нагрузки и астатизма выходного напряжения. Методы: теория импульсных систем автоматического управления, математическое моделирование процессов в импульсных стабилизаторах напряжения и физическое макетирование. Результаты. Проведен анализ особенностей автономных систем электропитания, синтезирован закон управления и разработана модель импульсного стабилизатора напряжения. Предложен метод и найдены способы управления импульсными стабилизаторами напряжения, которые обеспечивают малую длительность переходных процессов и астатизм выходного напряжения. Разработаны алгоритмы микропрограммного управления, реализующие найденные способы управления. Разработана архитектура и встроенное программное обеспечение для микропроцессорной системы управления стабилизатором. Изготовлен однокристальный вычислительный модуль устройства управления на базе программируемой интегральной схемы. Разработан и изготовлен макет импульсного стабилизатора с цифровым управлением на основе однокристального вычислительного модуля. Результаты экспериментального исследования макета подтверждают эффективность разработанного устройства управления, а именно достижение минимальной конечной длительности переходных процессов, вызванных ступенчатым изменением тока нагрузки, близкой к двум периодам преобразования и астатизма выходного напряжения. Показано, что применение импульсного стабилизатора, использующего полностью цифровой контур управления и реализуемого при помощи высокоскоростных микропроцессорных средств, имеет значительные преимущества по сравнению с аналоговыми вариантами.

Particle Swarm Optimization-Based Power and Temperature Control Scheme for Grid-Connected DFIG-Based Dish-Stirling Solar-Thermal System

Variable-speed operation of a dish-Stirling (DS) concentrated solar-thermal power generating system can achieve higher energy conversion efficiency compared to the conventional fixed-speed operation system. However, tuning of the controllers for the existing control schemes is cumbersome due to the presence of a large number of control parameters. This paper proposes a new control system design approach for the doubly-fed induction generator (DFIG)-based DS system to achieve maximum power point tracking and constant receiver temperature regulation. Based on a developed thermo-electro-pneumatic model, a coordinated torque and mean pressure control scheme is proposed. Through steady-state analysis, the optimal torque is calculated using the measured insolation and it serves as the tracking reference for direct torque control of the DFIG. To minimize the tracking error due to temperature variation and the compressor loss of the hydrogen supply system, four optimal control parameters are determined using particle swarm optimization (PSO). Model-order reduction and the process of the pre-examination of system stability are incorporated into the PSO algorithm, and it effectively reduces the search effort for the best solution to achieve maximum power point tracking and maintain the temperature around the set-point. The results from computational simulations are presented to show the efficacy of the proposed scheme in supplying the grid system with smoothened maximum power generation as the solar irradiance varies.

The R249Q hypertrophic cardiomyopathy myosin mutation decreases contractility in Drosophila by impeding force production.

Hypertrophic cardiomyopathy (HCM) is a genetic disease that causes thickening of the heart's ventricular walls and is a leading cause of sudden cardiac death. HCM is caused by missense mutations in muscle proteins including myosin, but how these mutations alter muscle mechanical performance in largely unknown. We investigated the disease mechanism for HCM myosin mutation R249Q by expressing it in the indirect flight muscle of Drosophila melanogaster and measuring alterations to muscle and flight performance. Muscle mechanical analysis revealed R249Q decreased muscle power production due to slower muscle kinetics and decreased force production; force production was reduced because fewer mutant myosin cross-bridges were bound simultaneously to actin. This work does not support the commonly proposed hypothesis that myosin HCM mutations increase muscle contractility, or causes a gain in function; instead, it suggests that for some myosin HCM mutations, hypertrophy is a compensation for decreased contractility. Hypertrophic cardiomyopathy (HCM) is an inherited disease that causes thickening of the heart's ventricular walls. A generally accepted hypothesis for this phenotype is that myosin heavy chain HCM mutations increase muscle contractility. To test this hypothesis, we expressed an HCM myosin mutation, R249Q, in Drosophila indirect flight muscle (IFM) and assessed myofibril structure, skinned fibre mechanical properties, and flight ability. Mechanics experiments were performed on fibres dissected from 2-h-old adult flies, prior to degradation of IFM myofilament structure, which started at 2days old and increased with age. Homozygous and heterozygous R249Q fibres showed decreased maximum power generation by 67% and 44%, respectively. Decreases in force and work and slower overall muscle kinetics caused homozygous fibres to produce less power. While heterozygous fibres showed no overall slowing of muscle kinetics, active force and work production dropped by 68% and 47%, respectively, which hindered power production. The muscle apparent rate constant 2πb decreased 33% for homozygous but increased for heterozygous fibres. The apparent rate constant 2πc was greater for homozygous fibres. This indicates that R249Q myosin is slowing attachment while speeding up detachment from actin, resulting in less time bound. Decreased IFM power output caused 43% and 33% decreases in Drosophila flight ability and 19% and 6% drops in wing beat frequency for homozygous and heterozygous flies, respectively. Overall, our results do not support the increased contractility hypothesis. Instead, our results suggest the ventricular hypertrophy for human R249Q mutation is a compensatory response to decreases in heart muscle power output.

A photon source based on the quantum well/dot structure in a microcavity

A scheme for the photon generation induced by the electron optical transition in a semiconductor structure consisting of a quantum dot and two quantum wells is proposed. A nanobeam photonic crystal microcavity is used as a source of the driving field and for concentrating the electromagnetic energy emitted during the cascade transport of electrons. We calculate the population dependences of the electron and microcavity Fock states as well as the average number of photons (a radiation power) on time, a mode decay rate and electron tunneling rates between the quantum dot and metal contacts. The generation power is shown to be root-dependent on the tunneling rates, and the maximum generation power is limited by the photon dissipation rate.

Equilibrium Core Design of Reaktor Daya Eksperimental

A prototype of a high temperature gas-cooled reactor for electric and cogeneration application, called Reaktor Daya Eksperimental (RDE) is being developed at BATAN. RDE is developed to fulfill the huge yet distributed Indonesian energy demand, in particular for the eastern part of Indonesia. As a moving fuel core, analysis of the fuel management of PBR can be divided into the analysis of the start-up phase where the core composition, neutron flux, and power density profile still changing and equilibrium core. Equilibrium core design usually represent the general performance over the entire range of reactor operation. As part of the design development, current paper presents the equilibrium core design of RDE and depressurized-loss-of-forced-cooling (DLOFC) accident analysis. PEBBED code is utilized for the equilibrium core analysis. Results of this study include several possible equilibrium designs for RDE which then the design with 123 fuel pebble recirculated per day with equilibrium keff 1.02571, discharge burnup of 79.36 and maximum power generation 0.66kW per pebble fuel is chosen. Maximum fuel temperature of this design under the DLOFC accident is 1015.9°C which occurred 8.5h after the initiation of the accident. Results of DLOFC accident shows the strong passive safety features of RDE.

Preliminary design study of wellbore heat exchanger in binary optimization for low – medium enthalpy to utilize non-self discharge wells in Indonesia

Indonesia has a large potential in geothermal energy resources. However, the development of the geothermal industry in Indonesia is still focused on high-temperature or high-enthalpy fields. There are 246 geothermal areas in Indonesia which classified into low to medium enthalpy, which is potentially able to be developed with binary system. In this paper, an experimental design was studied by modifying the Organic Rankine Cycle at the wellhead generating unit. This design utilizes non-self-discharge wells to be used as “heat exchanger” where the working fluid is pumped into the well through a U-pipe and heated by the geothermal fluid. The outflow of the working fluid from the U-pipe is expected to be steam-phased and directly flowed into the turbine. Several working fluids have been studied to determine maximum power generation at a certain reservoir temperature. In this study, pressure and temperature profile of well XX-02 is used for case study. XX-02 is non-self discharge well and medium temperature-water dominated reservoir.The working fluids evaluated were Isobutane, Propane, Isopentane, and Butane. The maximum generation output was found in Isobutane and Butane with generation output 294 kW and 241 kW respectively, and flow rate needed was 5 kg/s. This un-significant generation give flexibility in working fluid selection. Sensitivity analysis of the temperature decline from near wellbore was conducted to evaluate the feasibility of the design for 30 years project lifetime. Economics analysis was also have been done to study the feasibility of the design and electric price produced. ORC (Organic Rankine Cycle) price used in economic analysis is the average price of ORC (3,000 USD/kWh), resulting electricity price produced is 7.76 USD cents/kWh. This result conclude that Wellbore Heat Exchanger design is feasible to improve non-self discharge well to be economically developed.