共查询到20条相似文献,搜索用时 31 毫秒
1.
Paweena Jariyathitipong ;Kazuyoshi Hosotani ;Takashi Fujii ;Toshiki Ayano 《土木工程与建筑:英文版》2014,(11):1403-1413
The deterioration of concrete by sulfuric acid attack in sewage environments has become a serious problem for many existing sewage structures. In this study, the properties of concrete using the blast furnace slag have been examined. It was shown that by using the blast furnace slag fine aggregate and blast furnace slag fine powder, it is possible to enhance the resistance of mortar and concrete to sulfuric acid. The resistance to sulfuric acid of mortar and concrete can be improved by using a blast-furnace slag fine aggregate in the total amount of fine aggregate. When mortar or concrete reacts to sulfuric acid, dihydrated gypsum film is formed around the particulate of the fine aggregate. This dihydrated gypsum film could retard the penetration of sulfuric acid, thus, improving the resistance to sulfuric acid. Furthermore, it has been proved that the relationship between the erosion depth by sulfuric acid attack and the product of immersion period and concentration of sulfuric acid can be expressed linearly. However, this relationship is dependent on the type of materials of concrete. 相似文献
2.
Aamer Najim Abbas 《土木工程与建筑:英文版》2014,(12):1556-1566
This paper investigates the strength and deformation characteristics of reinforced normal and high-strength concrete rectangular beams which failed in shear and repaired by external bonding of carbon fiber and steel plate. Five simply supported reinforced concrete beams with shear reinforcement are tested, three of which are made with NSC (normal-strength concrete) and the other two with HSC (high-strength concrete). The span of the simply supported beams is 0.9 m with 100 mm wide by 200 mm deep cross section. All five beams are tested under four-point bending. Careful repair process is adopted and proved successful. The aim is to restore or increase shear strength of these beams and to monitor their post-repair load-deflection behavior. The effect of concrete compressive strength on the behavior and strength of beams before and after repair is also investigated. Shear cracks patterns and their evolution are observed and discussed. 相似文献
3.
The overall problem with PV (photovoltaic) systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal (PV/T) collector show the potential of obtaining high total energy efficiency. 相似文献
4.
Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of solar technology in terms of global availability using PV (photovoltaic) technology and actual energy production. Solar energy is widely under-used and one way to reduce this is to improve production in low-energy places with high demand: large cities. According to this option, about 40% of the electricity consumption in the built environment could be produced by solar PV systems and energy storage systems. This paper discusses conditions in the built environment and functional and design qualities enabling an increased diffusion of the technologies In a comparative analysis of PV technologies, the criteria taken into account encompass efficiency of the type of solar cell and commercial availability. Special attention is paid to the design features of different PV systems, like flexibility, colour and transparency that might help in their utilization as integrated in building material and ornaments in modem architecture. The same procedure is followed for electricity storage devices. The preliminary conclusion is that at present the freedom of design is largest for a combination of crystalline silicon PV cells and Li-ion batteries. 相似文献
5.
This paper describes procedure for estimation of travel time on signalized arterial roads based on multiple data sources with application of dimensionality reduction. Travel time estimation approach incorporates forecast of transportation nodes impendence and travel time on network links. Forecasting period is two hours and the estimation is based on historical data and real time data on traffic conditions. Travel time estimation combines multivariate regression, principal component analysis, KNN (k-nearest neighbours), cross validation and EWMA (exponentially weighted moving average) methods. When comparing estimation methodologies, relevantly better results were achieved by KNN method than with EWMA method. This is true for every time interval considered except for evening time interval when signalized arterial roads were uncongested. 相似文献
6.
Commonly proposed concepts, like KBS-3V, for disposal of highly radioactive waste imply construction at medium depth (400-600 m) in granitic rock, which is excellent for constructing a stable repository. VDH (very deep boreholes) represent an altemative concept with the advantage that the rock is much less permeable and that the very salt, heavy groundwater is stagnant. Both require engineered barriers in the form of canisters and waste-embedding clay but for somewhat different purposes. Canisters are the most important waste-isolating barriers for KBS-3V but are less important for VDH. The waste-embedding clay is needed for preserving the KBS-3V canisters by being tight and ductile, but plays a minor role for the VDH. The backfilled deposition tunnels in a KBS-3V repository provide very limited hindrance of radionuclides to move to the biosphere while the clay seals of VDH effectively prevent possibly released radionuclides to reach up to the biosphere. Comparison of the KBS-3V and VDH concepts indicates that the last mentioned one has several advantages but that certain issues remain to be worked on for becoming a number one candidate. 相似文献
7.
Aydin Tabrizi Paola Sanguinetti 《土木工程与建筑:英文版》2014,(8):963-972
In the United States, university buildings use 17% of total non-residential building energy per year. According to the NREL (National Renewable Energy Laboratory), the average lifecycle of a building in a university is 42 years with an EUI (energy use intensity) of 23 kWh/m^2/y. Current building and energy codes limit the EUI to 16 kWh/m^2/y for new school buildings; this benchmark can vary depending on climate, occupancy, and other contextual factors. Although the LEED (leadership in energy and environmental design) system provides a set of guidelines to rate sustainable buildings, studies have shown that 28%-35% of the educational LEED-rated buildings use more energy than their conventional counterparts. This paper examines the issues specific to a LEED-rated design addition to an existing university building. The forum, a lecture hall expansion of to an existing building at the University of Kansas, has been proposed as environmentally friendly and energy-efficient building addition. Comfort and health aspects have been considered in the design in order to obtain LEED platinum certificate. The forum's energy performance strategies include a double-skin facade to reduce energy consumption and PV (photovoltaic) panels to generate onsite energy. This study considers various scenarios to meet NZEB (net-zero energy building) criteria and maximize energy savings. The feasibility of NZE criteria is evaluated for: (a) seasonal comparison; (b) facility occupancy; (c) PV panels' addition in relation to double skin facade. The results of NZEB approach are compared to LEED platinum requirements, based on Rol (return on investment) and PV panel's efficiency for this specific educational building. 相似文献
8.
The new architecture may provide unusual opportunities for the abandoned areas involved by former industrial processes, both in the city centers and in the landscape. In fact, it may create new centralities and give new collective function for deprived areas. The case study of the architectural and educational project for a new museum park devoted to the technique and the science in the Apennine' s landscape near Parma (Italy) may give an interesting point of view about the role of the teaching and the research of the architecture in the former industrial heritage, and to avoid the abandonment and the pauperization of the territory around. 相似文献
9.
The goal of this study is to determine specific guidelines for Iraqi architects to contribute to the design and composition of energy-efficient housing units within the limits of a normal budget, locally available materials and technologies. These units can provide comfort despite the current energy situation in Iraq. The study is based on a computer simulation for a reference building in Baghdad, which has been selected according to the urban conditions, building legislations, housing market and statistics. The final results displayed the main recommendations and the possibility to achieve up to 50% energy reduction with a pay-back period not exceeding two years in some cases. There are some measures that have big energy saving potential. Yet, some of the measures may require big investment or have some bad environmental impacts. Some other good measures are already being implemented. 相似文献
10.
Ulrike Heine 《土木工程与建筑:英文版》2014,(4):395-404
Teaching design incorporating a sense of sustainability to architecture students is a challenge today, primarily because of the trend to label every design as sustainable or green even though it is no different from a more traditional one. The result is a "green-washed" education in architecture. To address this issue, this paper describes a teaching methodology of architectural design with a special focus on sustainability implemented in the Graduate School of Architecture in Clemson. This method includes an analysis of the location, the climate conditions, the materials needed and the construction process. Knowing that sustainable design is generally perceived as being expensive, there is a special focus on simplicity and affordability. Rather than relying on expensive technical solutions, students are encouraged to design for the given environment and apply passive strategies. In the approach discussed in this paper, the design process is a number of logical scientific decisions rather than an intuitive draft. The goal of this pedagogy is to raise awareness about how to handle global resources carefully and to show the importance of the later performance of the project as a key to design. The teaching strategy is described here along with the successful participation by our graduate students in a number of refereed competitions. 相似文献
11.
Up to now, reuse and recycling of existing buildings have not been examined widely. This paper discusses the theories, methods and practicalities of buildings' end of life with a main focus on planning and managing reuse and recycling of existing buildings. Our aim is the realistic modelling of theoretical scenarios for end of life based on a case study. The methods of building survey, material classification and documentation for reuse, recycling and disposal of existing constructions are presented. Investigations and calculations were done on an existing cottage in the Alps. The ecologically most beneficial disposal phase of the old wooden hut is our main objective. Critical questions arise from the quality of the material and how it can be extracted, separated and balanced in an appropriate way. A systematic survey of the building by inspection of constructions and materials in iterative steps allows a detailed material balance with condition and property information. This information is crucial for scenarios and material flow analysis of demolished and rebuilt building in environmental system analysis. For future planning, the reuse and recycling of existing buildings should be integrated quite early in the planning process so that we can use the materials in the best way. 相似文献
12.
Mahasti Tafahomi 《土木工程与建筑:英文版》2014,(11):1380-1388
In post-disaster emergency shelter aid, various relief agencies and other actors with different backgrounds need to cooperate in a tremendously short amount of time and under very different circumstances. In this article, we describe a research project that develops and tests a new approach in which the demands for shelters in a specific situation are methodically connected with available, innovative and sustainable shelter solutions, a DSS (decision support system). The DSS is a digital tool that translates the gathered evidence on needs, solutions and location including long-term effects of shelter provision into advice for the provision of sustainable, integral broader shelter solutions and designs. The outcome is a set of characteristics for a DSS for the provision of on-demand emergency shelters. A DSS that meets these characteristics leads to the provision of sustainable shelters that meet the needs of the users and, therefore, have higher performance in long term. 相似文献
13.
Energy is one of the most important resources in the economy of developing countries. Jordan depends mainly on imported oil and gas at international prices. This creates a heavy burden upon Jordanian national economy, which is reflected in the same time on other sectors of the Jordanian society. The ever increasing fuel prices make it very necessary to look for new renewable energy resources. Jordan as a developing country with its fast growing urban development and construction projects will be studied. It is worthy to study the dynamic relationship between end user, fuel and comfort in the residential sector. Energy is a chronic problem in Jordan, due to lack of non renewable energy resources, the end consumer is influenced by this fact, in achieving his basic energy needs. This study tries to shed light on the fuel poverty line, definitions and parameters of fuel poverty. And to study what has been done in this regard on both international and local level. No studies have been identified in Jordan which, explore the problem of fuel poverty, especially after the vast and recent increase in fuel prices internationally and locally. This study will follow theoretical and field survey to understand the relationship between comfort, energy and building fabric. Method will depend mainly on field survey and statistical data, and necessary measurements, questionnaires will be adopted when necessary to explore comfort levels related to fuel consumption. Summary and recommendations will be concerned with how thermal comfort could be achieved within the ranges of fuel accessibility, building fabric, minimum pollution and cost. 相似文献
14.
Andrea Immendoerfer Volker Stelzer Klaus-Rainer Braiutigam Juliane Joerissen 《土木工程与建筑:英文版》2014,(10):1253-1259
If Europe is to achieve the planned transition to a low carbon economy by 2050, succeeding in improving the energy efficiency of the largely inefficient existing building stock will be pivotal. Certain energy efficiency retrofitting obligations have now emerged as part of the EU's Energy Performance in Buildings Directive and the Energy Efficiency Directive. Challenges for retrofitting currently include gaps in technical skills both amongst building trades and professionals, a lack of awareness of building owners and users, concerns about compromising cultural heritage as well as a lack of viable business models, comparatively high cost and resulting long pay-back periods currently hamper the progress. Lessons can be drawn here form the EU-funded initiative CONCERTO, which helped 58 communities in 23 countries to reduce their dependence on conventional energy supply by implementing energy efficiency measures and integrating renewable energy sources not at single building scale but community scale. Almost all of these entailed retrofitting activities bad to find solutions to the issues mentioned. This paper presents a selection of conclusions regarding retrofitting to be drawn from the analysis undertaken under the project CONCERTO premium, which analysed outcomes across the 58 projects on behalf of the European Commission and focuses in particular on the political relevance of outcomes. 相似文献
15.
Raffaele Pernice 《土木工程与建筑:英文版》2014,(6):761-771
During the 1960s, many changes reshaped the economy, the society and the arts. The Cold War, the Space Race, the construction of a new middle class in most western societies led by the postwar economic prosperity with unprecedented urban growth followed by severe environmental problems fostered the design of spectacular urban utopian cities and mega-architectures. In those years, Japan was the source of highly influential bold and visionary urban and architectural ideas which relied on advanced technology. These ideas were conceived on the thought that cities could be seen as gigantic but impermanent entities able to transform itself according to an organic process of adaptation of its elementary components. This paper briefly revisits and critically discusses the legacy of the iconic mega-strnctural projects of Japanese Metabolist Movement and other visionary architects and planners of the 1960s, such as Paolo Soleri, Buckminster Fuller, Archigram. It attempts to enlighten the continuity with contemporary innovative and experimental urban models and ideas for the society and the city of the future, such as the Smart Cities, Eco-Cities, Green Urbanism, whose design is led by concerns related to climate change, the necessity of energy efficiency, the improvement of urban landscape and the valorization of depleted natural resources. 相似文献
16.
17.
The partial substitution of clinker by mineral additions offers very significant, both economical and environmental benefits. This adds value to industrial waste, and contributes also in the preservation of natural resources, like clay and limestone, as well as the reduction of greenhouse gas emissions (CO2). This study is interested in the simultaneous effect of BFS (blast furnace slag) and SF (silica fume) on setting time and water requirement of cement paste. The volumetric variations are tested in mortars, prepared in the same mixture of pastes, and the tests indicate that the addition of slag increase the fluidity, reduce the water demand, shrinkage and expansion, compared to the mortar, containing ten percent (10%) of Silica Fume only. The images of pastes obtained by SEM (scanning electron microscopy), are indicated an improvement of the microstructure of the paste with a large amount of slag, which leads to improve durability. 相似文献
18.
Sebastian Toplak 《土木工程与建筑:英文版》2014,(3):332-338
Combination of a bus system and cable car system can reduce the overall congestion of traffic in urban areas, where surrounding hills or mountains hold larger settlements or tourist and recreational infrastructure. With this kind of integration number of individual car trips can be significantly reduced. In this paper, the authors present an analysis of the pilot project implementation, which was held in Maribor. The authors conducted a limited test trial of two means of transportation, combining them into a single operating transport offer for inhabitants and tourists. Combined transport option proved to be a good starting point for reduction of traffic and parking congestion during winter tourist season and beyond. Method used in the research, in order to gain actual potential of integrating two systems and improving public transport offer, was establishment and implementation of the pilot project in Maribor during January 2011. Data was gathered through interviews of two interest groups. The first covered the users who were brought to the foothills of Pohorje's ski center by bus. The second covered the cable car users that were traveling to the top of Pohorje. For a limited time period, a trial principle of a single ticket was established, which gave ski-pass holders free bus ride on bus line No. 6. With the aim of reducing CO2, test drives of hybrid bus and compressed natural gas bus were conducted alongside many promotional activities with which users were informed of importance of environmentally friendly mobility options. 相似文献
19.
Nadhir Al-Ansari ;Mawada Abdellati ;Mohammad Ezeelden ;Salahalddin S. Ali ;Sven Knutsson 《土木工程与建筑:英文版》2014,(6):790-805
Iraq is facing water shortage problem despite the presence of the Tigris and Euphrates Rivers. In this research, long rainfall trends up to the year 2099 were studied in Sulaimani city northeast Iraq to give an idea about future prospects. The medium high (A2) and medium low B2 scenarios have been used for purpose of this study as they are more likely than others scenarios, that beside the fact that no climate modeling canter has performed GCM (global climate model) simulations for more than a few emissions scenarios (HadCM3 has only these two scenarios) otherwise pattern scaling can be used for generating different scenarios which entail a huge uncertainty. The results indicate that the average annual rainfall shows a significant downward trend for both A2 and B2 scenarios. In addition, winter projects increase/decrease in the daily rainfall statistics of wet days, the spring season show very slight drop and no change for both scenarios. However, both summer and autumn shows a significant reduction in maximum rainfall value especially in 2080s while the other statistics remain nearly the same. The extremes events are to decrease slightly in 2080s with highest decrease associated with A2 scenario. This is due to the fact that rainfall under scenario A2 is more significant than under scenario B2. The return period of a certain rainfall will increase in the future when a present storm of 20 year could occur once every 43 year in the 2080s. An increase in the frequency of extreme rainfall depends on several factors such as the return period, season of the year, the period considered as well as the emission scenario used. 相似文献
20.
The theory of constraints thinking process, created by Israeli physicist Eliyahu M. Goldratt, has emerged as a tool for achieving competitive advantage. Many researches also focused on the application of lean thinking developed by Toyota and proposed by Ohno. This philosophy has been proven to be effective in several production processes. This paper aims to propose a method of problem solving through the integration of theory of constraints thinking process and the principles of lean production. As a tool for problem identification, the method defends the use of current reality tree and, to solve problems, the lean thinking tools, proposed by Picchi. The developed method was implemented in a contractor. The research methodology was research-action. Among the results, there was a realistic diagnosis about the core problems in company. According to this, the core problem of the contractor is “the lack of commitment of manpower” that results in the main problem “the financial loss”. The principle of perfection was verbalized as a proposal to solve the problems and the tools to be implemented for solving problems were “commitment of senior management to employees” and “simplicity in communication”. 相似文献