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The scattering coefficient, extinction coefficient and single scattering albedo of water-soluble in the radiative forcing of urban aerosols

In this paper, the optical depths, scattering coefficient, absorption coefficient, extinction coefficient and single scattering albedo were modeled using Optical Properties of Aerosols and Clouds (OPAC) by slightly altering the number densities of water soluble at spectral range of 0.25 – 1.00 µm for eight different relative humidities (RHs) (0, 50, 70, 80, 90, 95, 98 and 99 %). The data was used to calculate the radiative forcing (RF). The RF was observed to decrease at all RHs given rise to negative RF when compared, as we moved from the first model to the fifth model reflecting the dominance of cooling effect. The scattering coefficient as well as the extinction coefficients and single scattering albedo increases with RHs attributing to a more scattering aerosol. The regression analysis of the Ångstrom exponents and curvatures which helps in determining the sizes of atmospheric particles was done using SPSS 16.0 software. The analysis reveals that fine mode particles are dominant.


Albedo

The fraction of the incident radiation that is reflected from the surface is called the albedo. Albedo plays a major role in the energy balance of the earth’s surface, as it defines the rate of the absorbed portion of the incident solar radiation. Soil albedo is a complex feature, which is determined by many soil dependent and independent (environmental) characteristics. The process that results in the reflected radiation is called reflectance, whereby the energy of radiation is reradiated by the chemical constituents (e.g., atoms or molecules) of the surface layer approximately half the thickness of wavelength.


Absorption, scattering and single scattering albedo of aerosols obtained from in situ measurements in the subarctic coastal region of Norway

In situ measurements of aerosol optical properties were made in summer 2008 at the ALOMAR station facility (69◦ 16 N, 16◦ 00 E), located at a rural site in the North of the island of Andøya (Vesteralen archipelago), about 300 km north of the Arctic Circle. The extended three months campaign was part of the POLAR-CAT Project of the International Polar Year (IPY-2007-2008), and its goal was to characterize the aerosols of this sub-Arctic area which frequently transporte to the Arctic region. The ambient lightscattering coefficient, σs (550 nm), at ALOMAR had a hourly mean value of 5.412 Mm−1 (StD = 3.545 Mm−1) and the light-absorption coefficient, σa (550 nm), had an hourly mean value of 0.400 Mm−1 (StD = 0.273 Mm−1 10).


Nhiên liệu sinh học tại Việt Nam: Để phát triển nhanh, cần giải pháp đồng bộ

Các doanh nghiệp sản xuất phân phối nhiên liệu sinh học vẫn đang chờ đợi Chính phủ sớm ban hành lộ trình bắt buộc sử dụng nhiên liệu xanh tại Việt Nam và xây dựng cơ chế nhằm tạo sự gắn kết lâu dài, hài hòa lợi ích giữa nhà sản xuất, người thu mua và nông dân; trong đó ban hành các quy hoạch cứng về vùng trồng sắn nguyên liệu để nông dân yên tâm đầu tư trồng trọt.


Giải pháp hoạt động hỗn hợp gió - Diesel đảo Phú Quý

Hệ thống cung cấp điện độc lập từ các nguồn phân tán cho các vùng không có lưới điện Quốc gia đang được quan tâm. Trong bài viết này, nhóm tác giả giới thiệu một số vấn đề cần giải quyết trong quá trình vận hành hệ thống lai ghép 3 Turbine gió và 6 tổ máy phát Diesel trên đảo Phú Quý. Từ đó, nhóm tác giả đề xuất giải pháp nhằm nâng cao khả năng huy động công suất của các Turbine gió, đảm bảo sự ổn định của hệ thống điện trên đảo và giảm giá thành sản xuất điện.


Vibrational effect on unidirectional timedependent angular momentum in low-symmetry aromatic ring molecule induced by two linearly polarized UV laser

In this study, we present the results of a theoretical study of the time-dependent angular momentum equation for low-symmetry aromatic ring molecule combine with vibrational effect using two linearly polarized UV laser.


Nghiên cứu và phân tích nguồn gốc ô nhiễm không khí ở thành phố Huế thông qua rêu Barbular bằng phần mềm Statistica 8.0

Bài viết này tiến hành nghiên cứu đo nồng độ nguyên tố trong mười sáu mẫu rêu Barbular thu thập tại thành phố Huế, được phân tích bằng phương pháp phân tích kích hoạt neutron (Neutron Activation Analysis) tại Viện Nghiên cứu Hạt nhân Dubna – Nga.


Bài dự thi Hội thi sáng tạo kỹ thuật Trần Đại Nghĩa: Giải pháp tái sử dụng nguồn năng lượng dư thừa làm đèn tiết kiệm năng lượng góp phần bảo vệ môi trường

Nội dung bài dự thi trình bày nhằm góp phần trong việc bảo vệ môi trường, sử dụng năng lượng một cách tiết kiệm, tác giả đã có ý tưởng tái sử dụng các nguồn năng lượng dư thừa và rác thải để chế tạo các sản phẩm phục vụ đời sống con người mà chủ yếu là chế tạo các loại đèn Led. Sự kết hợp này vừa mang lại lợi ích về kinh tế, vừa phát huy được khả năng sáng tạo trong việc thiết kế đèn, vừa góp phần bảo vệ môi trường đồng thời có thể triển khai mở rộng cho học sinh bậc trung học.


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.


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.


Structural assessment of reactor pressure vessel under multi layered corium formation conditions

In the present study, several key factors related to molten corium behaviors and thermal characteristics were examined under multi-layered corium formation conditions. Thereafter, systematic finite element analyses and subsequent damage evaluation with varying parameters were performed on a representative reactor pressure vessel (RPV) to figure out the possibility of high temperature induced failures.


Status of the astrid core at the end of the preconceptual design phase 1

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth).


Severe accident issues raised by the fukushima accident and improvements suggested

This paper revisits the Fukushima accident to draw lessons in the aspect of nuclear safety considering the fact that the Fukushima accident resulted in core damage for three nuclear power plants simultaneously and that there is a high possibility of a failure of the integrity of reactor vessel and primary containment vessel.


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.


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.


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.


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.


Study on the recycling of nuclear graphite after micro-oxidation

In this paper, a feasible strategy for the recycling of nuclear graphite is reported, based on the formation mechanism and the removal of carbon-14 by micro-oxidation. We investigated whether ground micro-oxidation graphite could be used as a filler to make new recycled graphite and which graphite/pitch coke ratio will give the recycled graphite outstanding properties (e.g., apparent density, flexural strength, compressive strength, and tensile strength).


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.


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.


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.


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.


Sensitivity analyses of the use of different neutron absorbers on the main safety core parameters in mtr type research reactor

In this paper, three types of operational and industrial absorbers used at research reactors, including Ag-In-Cd alloy, B4C, and Hf are selected for sensitivity analyses. Their integral effects on the main neutronic core parameters important to safety issues are investigated. These parameters are core excess reactivity, shutdown margin, total reactivity worth of control rods, thermal neutron flux, power density distribution, and Power Peaking Factor (PPF). The IAEA 10 MW benchmark core is selected as the case study to verify calculations. A two-dimensional, three-group diffusion model is selected for core calculations.


Sensitivity analysis of core neutronic parameters in electron accelerator driven subcritical advanced liquid metal reactor

In addition, sensitivity of the core neutronic parameters in accelerator-driven subcritical advanced liquid metal reactors, such as electron beam energy (Ee) and source multiplication coefficient (ks), has been investigated. A Monte Carlo code (MCNPX_2.6) has been used to calculate neutronic parameters such as effective multiplication coefficient (keff), net neutron multiplication (M), neutron yield (Yn/ e), energy constant gain (G0), energy gain (G), importance of neutron source (4* ), axial and radial distributions of neutron flux.


Terrapower, LLC traveling wave reactor development program overview

The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel.


The effect of hydrogen and oxygen contents on hydride reorientations of zirconium alloy cladding tubes

The lower hydrogen contents and the slower cooling rate generated a larger fraction of radial hydrides, a longer radial hydride length, and a lower ultimate tensile strength and plastic elongation. In addition, the oxidized specimens generated a smaller fraction of radial hydrides and a lower ultimate tensile strength and plastic elongation than the nonoxidized specimens.


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.


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


Study of a betavoltaic battery using electroplated nickel 63 on nickel foil as a power source

A betavoltaic battery was prepared using radioactive 63Ni attached to a three-dimensional single trenched PeN absorber. The optimum thickness of a 63Ni layer was determined to be approximately 2 mm, considering the minimum self-shielding effect of beta particles. Electroplating of radioactive 63Ni on a nickel (Ni) foil was carried out at a current density of 20 mA/cm2 .


Study of core support barrel vibration monitoring using ex core neutron noise analysis and fuzzy logic algorithm

A distinct pattern of phase differences was observed for each of the vibration models. The developed fuzzy logic module demonstrated successful recognition of the vibration frequencies, modes, orders, directions, and phase differences within 0.4 ms for the beam and shell mode vibrations


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  • 19/07/2011
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