Numerical investigation on the flow and power of small-sized multi-bladed straight Darrieus wind turbine

Straight Darrieus wind turbine has attractive characteristics such as the ability to accept wind from random direction and easy installation and maintenance. But its aerodynamic performance is very complicated,especially for the existence of dynamic stall. How to get better aerodynamic performance arouses lots of interests in the design procedure of a straight Darrieus wind turbine. In this paper,mainly the effects of number of blades and tip speed ratio are discussed. Based on the numerical investigation,an assumed asymmetric straight Darrieus wind turbine is proposed to improve the averaged power coefficient. As to the numerical method,the flow around the turbine is simulated by solving the 2D unsteady Navier-Stokes equation combined with continuous equation. The time marching method on a body-fitted coordinate system based on MAC (Marker-and-Cell) method is used. O-type grid is generated for the whole calculation domain. The characteristics of tangential and normal force are discussed related with dynamic stall of the blade. Averaged power coefficient per period of rotating is calculated to evaluate the eligibility of the turbine.

k_(eff)uncertainty quantification and analysis due to nuclear data during the full lifetime burnup calculation for a small-sized prismatic high temperature gas-cooled reactor

To benefit from recent advances in modeling and computational algorithms,as well as the availability of new covariance data,sensitivity and uncertainty analyses are needed to quantify the impact of uncertain sources on the design parameters of small prismatic high-temperature gascooled reactors(HTGRs).In particular,the contribution of nuclear data to the k_(eff)uncertainty is an important part of the uncertainty analysis of small-sized HTGR physical calculations.In this study,a small-sized HTGR designed by China Nuclear Power Engineering Co.,Ltd.was selected for k_(eff)uncertainty analysis during full lifetime burnup calculations.Models of the cold zero power(CZP)condition and full lifetime burnup process were constructed using the Reactor Monte Carlo Code RMC for neutron transport calculation,depletion calculation,and sensitivity and uncertainty analysis.For the sensitivity analysis,the Contribution-Linked eigenvalue sensitivity/Uncertainty estimation via Track length importance Characterization(CLUTCH)method was applied to obtain sensitive information,and the "sandwich" method was used to quantify the k_(eff)uncertainty.We also compared the k_(eff)uncertainties to other typical reactors.Our results show that ^(235)U is the largest contributor to k_(eff)uncertainty for both the CZP and depletion conditions,while the contribution of ^(239)Pu is not very significant because of the design of low discharge burnup.It is worth noting that the radioactive capture reaction of ^(28)Si significantly contributes to the k_(eff)uncertainty owing to its specific fuel design.However,the k_(eff)uncertainty during the full lifetime depletion process was relatively stable,only increasing by 1.12%owing to the low discharge burnup design of small-sized HTGRs.These numerical results are beneficial for neutronics design and core parameters optimization in further uncertainty propagation and quantification study for small-sized HTGR.

Influence of decorative materials on cooling load of residential apartments

The influence of a polyvinyl chloride（PVC）-panel on the cooling load of a residential apartment in Mashad,Iran,is analyzed by the DeST-h software.And the summer natural ventilation of the residential apartment is investigated to determine the wind speed into the apartment through the computational fluid dynamics software.The evaluation results of the indoor wind velocity show that most parts of the apartment are comfortable.The cooling load of the penthouse can be decreased about 10.5% or 6.5% when an air layer exists or does not exist between the ceiling and the PVC-panel,respectively,indicating that the existence of the air layer can decrease the cooling load.However,the effect of the increase in the air layer＇s thickness on the decrease in the cooling load is obvious.Adding a thin layer of air between the ceiling and the PVC-panel is a good step toward sustainable buildings.

Assessment for Production and Operation Ability of Medium and Small-sized Enterprises Based on Neural Network

In order to improve production and operation ability of medium and small-sized enterprises, an assessment-index system of production and operation ability was proposed, and a corresponding assessment model was established based on BP neural network. The conjunction weights of the neural network were continuously modified from output layer to input layer in the process of neural network training to reduce the errors between the anticipated and actual outputs. The results from an example show that this method is reliable and feasible. The production and operation abilitv of an enterorise with assessed result of 0.833 is fairly oowerful, and that with assessed result of 0.644 is average.

Study on Contra-Rotating Small-Sized Axial Flow Hydro Turbine

It is thought that small hydropower generation is alternative energy, and the energy potential of small hydropower is large. The efficiency of small hydro turbines is lower than that of large one, and these small hydro turbine’s common problems are out of operation by foreign materials. Then, there are demands for small hydro turbines to keep high per- formance and wide flow passage. Therefore, we adopted contra-rotating rotors which can be expected to achieve high performance and low-solidity rotors with wide flow passage in order to accomplish high performance and stable opera- tion. Final goal on this study is development of an electric appliance type small hydro turbine which has high portability and makes an effective use of the unused small hydro power energy source. In the present paper, the performance and the internal flow conditions in detail of contra-rotating small-sized axial flow hydro turbine are shown as a first step of the research with the numerical flow analysis. Then, a capability adopting contra-rotating rotors to an electric appliance type small hydro turbine was discussed. Furthermore, the high performance design for it was considered by the numeri- cal analysis results.

A New Design of Student Apartment Bed Based on Kansei Engineering and Ergonomics

Aiming at the defects of the products available on the market at present and basing on the Kansei Engineering and Ergonomics, a new kind of student apartment bed which can prove its humanity more clearly is designed, and its design direction is gotten through the questionnaire and the design starts from the real actual needs of students. After the original design was finished, the later investigation on the students was engaged with and made the engineering analysis. The conclusion is that the sum of ＂perfect＂ and ＂good＂ membership rates is up to 64%, hence the comprehensive assessment of the design is perfect. That is to say, this design is able to realize and meet the needs of users, and there is no doubt that it will have a good business prospects.

Effect of Organic and Chemical Fertilizer Application on Growth, Yield, and Quality of Small-Sized Tomatoes

Tomatoes in Japan are generally cultivated under management systems that use chemical fertilizers and synthetic chemical pesticides. However, the continuous use of these fertilizers and pesticides damages the soil environment and reduces the number of soil microorganisms. Organic farming has a relatively low environmental impact compared to conventional farming techniques, but typically has lower and more unstable yields. In this study, we investigated the effect of organic and chemical fertilizer application on growth, yield, and quality of small-sized (cherry) tomatoes. Cherry tomatoes were cultivated using organic and chemical organic fertilizers. Average weight and lateral diameter were significantly higher under organic fertilizer than under chemical fertilizer. In addition, shoot dry weight was significantly higher under organic fertilizer than chemical fertilizer. Lycopene content was significantly higher under organic fertilizer than chemical fertilizer. The total carbon (TC), total phosphorus (TP), total potassium (TK), available phosphoric (SP) and exchangeable potassium (SK) contents, C/N ratio, and pH were significantly higher under organic fertilizer than chemical fertilizer. Bacterial biomass, nitrite (NO? 2-N) oxidation activity, nitrification (N) circulation activity, and phosphoric (P) circulation were higher under organic fertilizer than chemical fertilizer. From these results, the study indicates that appropriate controls such as TC, total nitrogen (TN), and C/N ratio of organic fertilizer increased microbial biomass and enhanced nutrient circulation such as N circulation activity and P circulation activity. These results can be used to improve current organic farming practices and promote soil conservation.

Electricity consumption propensity of different household members in apartment house

South Korea is an energy-guzzling country.Economic reasons in the country force its households to save more energy.Household energy consumption in South Korea has grown slow compared to other sectors and household energy consumption per capita is lower than the OECD (Organization for Economic Co-operation and Development) average.However,its per capita electricity use soared and expected to keep climbing mainly due to the increasing number of one-person household.To establish effective strategy against a possible electricity shortage,the amount of electricity energy consumption needs to be understood clearly first.We adopted both general survey and detailed survey for people living in apartment housings and collected data on electrical instrument use according to individual schedule.Based on these data,we tried to analyze electricity consumption patterns resulting from energy using activities at home and find out electricity using tendency according to each family member's characteristics in apartment housings.

The Profit Model of Long-Term Lease Apartments Under Multi-Agent Supply

The acceleration of urbanization has led to an increase in the number of urban floating population, which leads to more demands for the housing rental market. With the support of policies, long-term lease apartments have begun to emerge. However, under the multi-subject supply, longterm lease apartments have encountered problems such as small profits in their development. Starting from the background of the development of long-term lease apartments, this study classified the main types of long-term lease apartments, analyzed the four profit models of comprehensive profit, expansion of rent difference, REITs and value-added services based on their business models, and proposed corresponding suggestions on the profitability of long-term lease apartments according to the current situation of profit difficulty of long-term lease apartments and the lack of profit models.

Outdoor Environmental Landscape Design of the Apartment for the Elderly in Southern Cities of China

On the basis of environmental psychology and environment-behavior science, this paper took Beijing Oriental Sun City Elderly Apartment for example to explore outdoor environmental landscape design schemes of the elderly apartment suitable for geomorphologic features, climatic conditions, and humanistic background of southern cities against the background of population aging in China, so as to provide references for the outdoor environment construction for the elderly apartment.

The role of furniture in exposure to non-ionizing radiation in a residential apartment

This article concerns the sources of non-ionizing radiation in a normal inhabited environment. Measurements show that residents are exposed to non-ionizing radiation in levels both below and above the European normative. Excess is present due to the fact that, producers of electronic equipment and appliances, those who use them, as well as those involved in the construction of housing, have insufficient acquaintance with non-ionizing radiation. Producers are advised to increase the coefficient of safety towards non-ionizing radiation by renewing technology. Users are advised to operate apparatus with the lowest possible power, to minimise time exposed to sources, to maximise the distance from them and to renew their appliances. Construction workers should take non-ionizing radiation more into consideration when furnishing of houses.

Horizontal Fire Spread in a Contemporary Apartment Based on a Real Fire

The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully instrumented with thermocouples, video cameras and gas extraction probes. The apartments were ignited successively whereupon the fire in the second apartment developed freely to post-flashover conditions and got the main focus in this report. The apartment was completely furnished with contemporary furniture and objects, and had an average fire load density for residential occupancy. A full description of the fire load, ventilation conditions and instrumentation are provided. The focus of this report is primarily to obtain conclusions on the horizontal spread of smoke throughout the apartment during the fire growth period. Velocities of smoke spreading were measured to be in the range below 0.05 m/s which means that the smoke migrated over the longest distance throughout the apartment for about 3 to 4 minutes while the flame did not leave the initial fire room. The main aim of the experiments was to collect a comprehensive set of data from a realistic and contemporary fire scenario to validate numerical simulations.

Ventilation of Apartment Buildings and Nursing Homes

The paper presents the results of the investigations into the indoor climate and energy efficiency of ventilation devices in residential buildings and nursing homes. The indoor climate studies discussed in the article were conducted in a nursing home where room ventilation is based on Meltem Air Handling Units (AHU). Similar studies have been carried out in apartment buildings where CO2 levels in bedrooms were compared before and after renovating the ventilation with Meltem AHU and installing exhaust fans in the bathroom/WC and kitchen. Tenants evaluate the use of Meltem AHU in apartments very positively. The article presents the efficiency results of Meltem AHU with different external air temperatures conducted in apartments in real-life situations. The study shows that skilful renovation of ventilation in old apartment buildings enables to achieve good indoor climate and energy saving at the same time.

Performance and Internal Flow of Contra-Rotating Small-Sized Cooling Fan

High pressure and large flow rate small-sized cooling fans are used for servers in data centers and there is a strong demand to increase its performance because of increase of quantity of heat from servers. Contra-rotating rotors have been adopted for some of high pressure and large flow rate cooling fans to meet the demand. The performance curve of the contra-rotating small-sized cooling fan with 40 mm square casing was investigated by an experimental apparatus and its internal flow condition was clarified by the numerical analysis. The fan static pressure of the front rotor was extremely low and it increased significantly at the rear rotor. The uniform flow was achieved at the inlet of the rear rotor because of the special shape of the casing between the front and rear rotors. On the other hand, the tip leakage flow was large enough to influence on the main flow of the test cooling fan by the design specification of high pressure with compact rotor diameter.

Internal Flow Condition between Front and Rear Rotor of Contra-Rotating Small-Sized Axial Fan at Low Flow Rate

Contra-rotating small-sized fans are used as cooling fans for electric equipment. The internal flow condition between the front and rear rotors of the contra-rotating small-sized fan is not known well especially at the low flow rate. Furthermore, the blade row distance between the front and rear rotors is an important parameter for the contra-rotating small-sized fan and its influence on the internal flow condition is not clarified at the low flow rate. Therefore, the internal flow condition of the contra-rotating small-sized fan at the low flow rate is investigated by the numerical analysis in this research. The numerical analysis results are validated by comparing the fan static pressure curves of the numerical results to the experimental results. The internal flow condition at the low flow rate is clarified using the numerical models of the different blade row distance L = 10 mm and 30 mm. In the present paper, pressure fluctuations phase locked each front and rear rotor’s rotation are shown and the influences of the wake and the potential interference are discussed by the unsteady numerical analysis results at the low flow rate.

Evaluation of Embodied Energy and Construction Costs for the Design of Low-Rise Apartments for Low-Income Residents in Surabaya, Indonesia

Low-rise apartments for low-income residents have been built in Surabaya in recent years. They have four stories and many rooms, and the dwellers are all small traders. Because these projects are built with funds from the government, the buildings are designed to consider the cost of construction, without consideration of embodied energy material. As a result, the buildings are not optimal in terms of embodied energy and construction cost. At present, because there are both concerns over global warning and a worldwide energy crisis, the embodied energy in a building is a very important concept for building design, because it can determine usage of energy in relation to natural sources, especially fossil fuels. This is part of the sustainable design concept. This paper describes research regarding： differences in embodied energy and construction cost between different wall materials, including brick, corn block and lightweight concrete in low rise apartments; the optimal relationship between embodied energy and building cost; and which factors determine these differences. The findings of this research show that lightweight concrete is the best material for the building walls; apartments for low-income in Surabaya still do not represent optimal construction design; and that sustainable buildings are cheaper than those that do not use this concept.

Study on Construction and Countermeasures of Technological Innovation Environment within Medium and Small-sized Enterprises in Hubei Province

Based on the application of the latest technological innovation theory and the successful experience generated by the domestic and overseas medium and small-sized enterprises, this thesis proposes a theoretical framework, strategic proposition and some secure measures for the regional technological innovation to promote the technological innovation within medium and small-sized enterprises in Hubei Province. In addition, the author also provides some tactics concerning the original motivation, technological market, innovation talents and innovation system, which aim at offering some consultation for the government decision, optimize industrial structure, implement the innovation strategy and propel to the medium and small-sized enterprises＇ development.

Space-to-Ground Quantum Key Distribution Using a Small-Sized Payload on Tiangong-2 Space Lab

Quantum technology establishes a foundation for secure communication via quantum key distribution （QKD）. In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum＋weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.

An Evaluation Method for the Potential of Old Apartment Buildings＇ Rehabilitation in Brazil

The rehabilitation of older buildings for residential use that started in the last few decades of the 20th century has become recurrent in some Brazilian cities. In Sao Paulo, for instance, this subject is within the context of the revitalization of its downtown area with the reintroduction of residential occupancy in the region as a consequence of actions taken by public and private groups. However, older buildings were designed based on the technologies and regulations available in the past and applied to meet the lifestyles of the time of their construction. This paper presents a method for the analysis of older apartment buildings, diagnosing their strengths and limitations in adapting to both the new Brazilian regulatory and legislative requirements, and the contemporary domestic demands. Requirements, criteria and methods for evaluation were studied, and defined as well as procedures for the application of a method which allows for a physical and systematic analysis of old apartment buildings. It was found that the proposed method can be an important support tool at the moment of studying the feasibility of rehabilitation processes, guiding and providing grounds for the design and building decisions of the professionals involved in these processes.

Study on Virtual Training Management in Small-sized Enterprises

This paper firstly analyses the necessity of virtual management in small-sized enterprises, then presents two main modes to implement virtual training management in small-sized enterprises. The paper also points out the best mode for the small-sized enterprises＇ training to implement virtual management.