Tài liệu miễn phí Năng lượng
Download Tài liệu học tập miễn phí Năng lượng
Ảnh hưởng của nhiệt độ đến tính chất quang điện của môđun pin mặt trời
Các đặc điểm thuận nghịch của cường độ dòng điện - điện áp (I-V) và điện dung - điện áp (C-V) của các môđun pin mặt trời silicon vô định hình đã được đo đạc nhằm nghiên cứu hiệu suất của chúng dưới ảnh hưởng của sự thay đổi nhiệt độ do tiếp xúc trực tiếp với nguồn nhiệt hoặc bị che khuất.
9/15/2019 7:58:45 AM +00:00
A review of renewable energy sources, sustainability issues and climate change mitigation.
The need for energy and its related services to satisfy human social and economic development, welfare and health is increasing. Returning to renewables to help mitigate climate change is an excellent approach which needs to be sustainable in order to meet energy demand of future generations. The study reviewed the opportunities associated with renewable energy sources which includes: Energy Security, Energy Access, Social and Economic development, Climate change mitigation, and reduction of environmental and health impacts. Despite these opportunities, there are challenges that hinder the sustainability of renewable energy sources towards climate change mitigation. These challenges include market failures, lack of information, access to raw materials for future renewable resource deployment, and our daily carbon footprint.
9/14/2019 11:16:42 AM +00:00
Giải pháp thu thập, xử lý số liệu phóng xạ trên tàu biển dùng máy tính
Để tăng độ chính xác của phép đo và nâng cấp, cải tiến hiệu năng làm việc của thiết bị, bài báo này trình bày một giải pháp dùng máy tính nhúng thu thập, xử lý số liệu phóng xạ cho các thiết bị đo phóng xạ đường biển trang bị trên các tàu hải quân, cảnh sát biển.
8/15/2019 3:10:18 PM +00:00
Cải thiện chất lượng nguồn điện mặt trời trong vi lưới
Hệ thống bánh đà lưu trữ năng lượng (FESS) là một công nghệ lưu trữ mới và có nhiều ưu điểm so với các phương pháp lưu trữ năng lượng truyền thống. Trong bài báo này chúng tôi trình bày một giải pháp tích hợp FESS với hệ thống điện mặt trời làm việc trong vi lưới nhằm cải thiện chất lượng nguồn điện mặt trời cung cấp cho lưới.
8/15/2019 3:04:49 PM +00:00
Nghiên cứu ảnh hưởng của nguồn năng lượng điện có công suất hạn chế đến chất lượng làm việc của hệ truyền động bám trên tàu hải quân
Bài báo trình bày kết quả nghiên cứu xây dựng mô hình hệ truyền động bám vị trí với hệ truyền động máy phát - động cơ (ЭМУ–Д) và đánh giá sự ảnh hưởng của giới hạn công suất nguồn năng lượng điện đến chất lượng động học hệ truyền động bám. Ngoài ra, bài báo trình bày các kết quả mô phỏng mô hình hệ truyền động bám pháo AK-725 trên tàu Hải quân khi tính đến ảnh hưởng của giới hạn công suất nguồn năng lượng điện.
8/15/2019 12:37:28 PM +00:00
Ảnh hưởng của kết cấu và vật liệu tạo tấm hấp phụ đến thông số nhiệt của bộ thu năng lượng mặt trời
Nghiên cứu khả năng nâng nhiệt của bộ thu nhiệt năng lượng mặt trời với kết cấu và vật liệu khác nhau là hết sức quan trọng để có cơ sở khoa học tính toán lựa chọn vật liệu và kết cấu bộ thu hợp lý cho các thiết bị ứng dụng nhiệt năng lượng mặt trời.
8/15/2019 12:12:10 PM +00:00
Nghiên cứu điều khiển hệ thống lai của nguồn pin mặt trời và pin nhiên liệu trong lưới điện nhỏ
Bài viết đã đưa ra được kết quả mô phỏng điều khiển hệ thống lai cho nguồn pin mặt trời và pin nhiên liệu sử dụng các bộ biến đổi điện tử công suất, nhằm duy trì công suất phát tối đa của hệ thống bất chấp tải nối với hệ thống.
7/16/2019 12:23:05 PM +00:00
Void fraction prediction for separated flows in the nearly horizontal tubes
The void fraction is calculated without any discontinuity at flow regime transitions by considering continuous changes of the interfacial geometric characteristics and interfacial friction factors across three typical separated flows, namely stratifiedesmooth, stratifiedewavy, and annular flows. An evaluation of the proposed model against available experimental data covering various types of fluids and flow regimes showed a satisfactory agreement.
7/15/2019 9:47:43 PM +00:00
Vibration signal analysis of main coolant pump flywheel based on hilbertehuang transform
In this paper, we present a HilberteHuang transform (HHT) algorithm for flywheel vibration analysis. The simulation indicated that the proposed flywheel vibration signal analysis method performs well, which means that the method can lay the foundation for the detection and diagnosis in a reactor main coolant pump.
7/4/2019 6:37:00 AM +00:00
Vibration displacement measurement technology for cylindrical structures using camera images
In this paper, a method is proposed to measure vibration displacements remotely using a camera without having to approach the structure. Furthermore, an estimation method for the measurement resolution and measurement error is proposed for the vibration displacement of a cylindrical structure measured using the proposed measurement method. The proposed methods are described, along with experimental results that verify their accuracy.
7/4/2019 6:36:43 AM +00:00
Verification of electromagnetic effects from wireless devices in operating nuclear power plants
This design change can improve the ability of the operators and personnel to respond to an emergency situation by using important equipment for a safe shutdown. IEEE 802.11 smartphones (Wi-Fi standard), Internet Protocol (IP) phones, personal digital assistant (PDA) for field work, notebooks used with web cameras, and remote site monitoring tablet PCs for on-site testing may be considered as wireless devices that can be used in domestic operating NPPs.
7/4/2019 6:36:28 AM +00:00
Variation of local pool boiling heat transfer coefficient on 3-degree inclined tube surface
The maximum and minimum local coefficients were observed at the azimuthal angles of 0° and 180°, respectively, in saturated water. The locations of the maxima and the minima were dependent on the inclination angle of the tube as well as the degree of subcooling. The major heat transfer mechanisms were considered to be liquid agitation generated by the sliding bubbles and the creation of big size bubbles through bubble coalescence. As a way of quantifying the heat transfer coefficients, an empirical correlation was suggested.
7/4/2019 6:36:12 AM +00:00
Validation of numerical methods to calculate bypass flow in a prismatic gas cooled reactor core
One of the important requirements for GAMMA+ and AGREE is an accurate modeling capability of a bypass flow in a prismatic core. Recently, a series of air experiments were performed at Seoul National University (SNU) in order to understand bypass flow behavior and generate an experimental database for the validation of computer codes. The main objective of the present work is to validate the GAMMA+ and AGREE codes using the experimental data published by SNU.
7/4/2019 6:35:48 AM +00:00
Validation of computational fluid dynamics calculation using rossendorf coolant mixing model flow measurements in primary loop of coolant in a pressurized water reactor model
The aim of this work is to simulate the thermohydraulic consequences of a main steam line break and to compare the obtained results with Rossendorf Coolant Mixing Model (ROCOM) 1.1 experimental results. The objective is to utilize data from steady-state mixing experiments and computational fluid dynamics (CFD) calculations to determine the flow distribution and the effect of thermal mixing phenomena in the primary loops for the improvement of normal operation conditions and structural integrity assessment of pressurized water reactors. The numerical model of ROCOM was developed using the FLUENT code.
7/4/2019 6:35:29 AM +00:00
Validation of a new design of tellurium dioxide irradiated target
The results show that the tightness of the targets is ensured up to 600C with the appearance of deformations on lids beyond 450C. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modesdconvection, conduction, and radiation.
7/4/2019 6:35:12 AM +00:00
Uv induced polymerization of size controlled platinum poly[styrene divinylbenzenetri(propylene glycol) diacrylate] hydrophobic catalyst beads in microfluidics
The catalytic exchange of hydrogen isotopes between hydrogen and water has been known to be a very useful process for the separation of tritium from tritiated water. For the process, a highly active hydrophobic catalyst is needed. This study provides an effective fabrication method of size-controlled platinum/poly[styrene-divinylbenzene-tri(propylene glycol) diacrylate] [Pt/poly(SDB-TPGDA)] hydrophobic catalyst beads with a narrow size distribution. Platinum nanoparticles were prepared by g-ray-induced reduction in the aqueous phase first, and then uniformly dispersed in SDB-TPGDA comonomer after the hydrophobization of platinum nanoparticles with alkylamine stabilizers.
7/4/2019 6:34:57 AM +00:00
U.s. fuel cycle technologies R&D program for next generation nuclear materials management
The U.S. Department of Energy’s Fuel Cycle Technologies R&D program under the Office of Nuclear Energy is working to advance technologies to enhance both the existing and future fuel cycles. One thrust area is in developing enabling technologies for next generation nuclear materials management under the Materials Protection, Accounting and Control Technologies (MPACT) Campaign where advanced instrumentation, analysis and assessment methods, and security approaches are being developed under a framework of Safeguards and Security by Design. An overview of the MPACT campaign’s activities and recent accomplishments is presented along with future plans.
7/4/2019 6:34:36 AM +00:00
Uranium Enrichment determination using a New Analysis code for the U XKa Region: HyperGam-U
To describe the X-ray peaks, a Lorentzian broadened shape function was used, and methods were developed to reduce the number of fitting parameters for decomposing the strongly overlapping peaks using channel-energy, energy-width, and energy-efficiency calibration functions
7/4/2019 6:34:23 AM +00:00
Uncertainty propagation analysis for yonggwang nuclear unit 4 by mccard master core analysis system
This paper concerns estimating uncertainties of the core neutronics design parameters of power reactors by direct sampling method (DSM) calculations based on the two-step McCARD/MASTER design system in which McCARD is used to generate the fuel assembly (FA) homogenized few group constants (FGCs) while MASTER is used to conduct the core neutronics design computation. It presents an extended application of the uncertainty propagation analysis method originally designed for uncertainty quantification of the FA FGCs as a way to produce the covariances between the FGCs of any pair of FAs comprising the core, or the covariance matrix of the FA FGCs required for random sampling of the FA FGCs input sets into direct sampling core calculations by MASTER.
7/4/2019 6:34:08 AM +00:00
Two dimensional simulation of hydrogen iodide decomposition reaction using fluent code for hydrogen production using nuclear technology
The operating characteristics of hydrogen iodide (HI) decomposition for hydrogen production were investigated using the commercial computational fluid dynamics code, and various factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare device performance with that expected for device development. Hydrogen production increased with an increase of the surface-to-volume (STV) ratio.
7/4/2019 6:33:50 AM +00:00
Turbulence modulation of the upward turbulent bubbly flow in vertical ducts
The present paper aims at improving the modeling of turbulence for the upward turbulent bubbly flow through the use of experimental databases that contain data on small and large vertical ducts. First, the role of bubble-induced turbulence was analyzed, which indicated the dominant role of the bubble-induced turbulence in the duct center for relatively high void fraction cases. Therefore, the turbulence therein was mainly focused on, which indicated that the stronger turbulence could be induced by bubbles in large ducts with similar void fractions as compared to that in small ducts.
7/4/2019 6:33:34 AM +00:00
Treating uncertainties in a nuclear seismic probabilistic risk assessment by means of the dempster shafer theory of evidence
In this paper, a Dempster-Shafer Theory (DST) framework for handling uncertainties in NPP SPRAs is proposed and applied to an example case study. The main contributions of this paper are two: (i) applying the complete DST framework to SPRA models, showing how to build the Dempster-Shafer structures of the uncertainty parameters based on industry generic data, and (ii) embedding Bayesian updating based on plant specific data into the framework.
7/4/2019 6:33:13 AM +00:00
Transient diagnosis and prognosis for secondary system in nuclear power plants
This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips.
7/4/2019 6:32:57 AM +00:00
Three dimensional flow phenomena in a wire wrapped 37-pin fuel bundle for sfr
The main purpose of the current study is to understand the three-dimensional complex flow phenomena in a wire-wrapped fuel assembly to support the license issue for the core design. Computational fluid dynamics results show good agreement with friction factor correlation models. The secondary flow in the corner and edge subchannels is much stronger than that in an interior subchannel. The axial velocity averaged in the corner and edge subchannels is higher than that averaged in the interior subchannels.
7/4/2019 6:32:40 AM +00:00
Thin plate type embedded ultrasonic transducer based on magnetostriction for the thickness monitoring of the secondary piping system of a nuclear power plant
Pipe wall thinning in the secondary piping system of a nuclear power plant is currently a major problem that typically affects the safety and reliability of the nuclear power plant directly. Regular in-service inspections are carried out to manage the piping system only during the overhaul. Online thickness monitoring is necessary to avoid abrupt breakage due to wall thinning.
7/4/2019 6:32:24 AM +00:00
The studies of irradiation hardening of stainless steel reactor internals under proton and xenon irradiation
Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth.
7/4/2019 6:32:09 AM +00:00
Thermal shock fracture of silicon carbide and its application to lwr fuel cladding performance during reflood
In this study, an experimental assessment of thermal shock performance of a monolithic alpha phase SiC tube was conducted by quenching the material from high temperature (up to 1200ºC) into room temperature water. Post-quenching assessment was carried out by a Scanning Electron Microscopy (SEM) image analysis to characterize fractures in the material. This paper assesses the effects of pre-existing pores on SiC cladding brittle fracture and crack development/propagation during the reflood phase. Proper extension of these guidelines to an SiC/SiC ceramic matrix composite (CMC) cladding design is discussed.
7/4/2019 6:31:51 AM +00:00
Thermale - hydraulic characteristics for canflex fuel channel using burnable poison in candu reactor
The thermalehydraulic characteristics for the CANadian Deuterium Uranium Flexible (CANFLEX)-burnable poison (BP) fuel channel, which is loaded with a BP at the center ring based on the CANFLEX-RU (recycled uranium) fuel channel, are evaluated and compared with that of standard 37-element and CANFLEX-NU (natural uranium) fuel channels. The distributions of fuel temperature and critical channel power for the CANFLEX-BP fuel channel are calculated using the NUclear Heat Transport.
7/4/2019 6:31:35 AM +00:00
The investigation of burnup characteristics using the serpent monte carlo code for a sodium cooled fast reactor
In this research, we investigated the burnup characteristics and the conversion of fertile 232Th into fissile 233U in the core of a Sodium-Cooled Fast Reactor (SFR). The SFR fuel assemblies were designed for burning 232Th fuel (fuel pin 1) and 233U fuel (fuel pin 2) and include mixed minor actinide compositions. Monte Carlo simulations were performed using Serpent Code1.1.19 to compare with CRAM (Chebyshev Rational Approximation Method) and TTA (Transmutation Trajectory Analysis) method in the burnup calculation mode.
7/4/2019 6:31:22 AM +00:00
The impact of power coefficient of reactivity on candu 6 reactors
In particular, CANDU reactors have always taken advantage of the small value of the PCR associated with their design characteristics, such that the overall design and safety characteristics of the reactor are not sensitive to the value of the PCR. For other reactor design concepts a PCR which is both large and negative is an important aspect in the design of their engineered systems for controlling reactivity.
7/4/2019 6:31:05 AM +00:00