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Sample records for external floating roof

  1. 40 CFR 65.45 - External floating roof converted into an internal floating roof.

    Science.gov (United States)

    2010-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Storage Vessels § 65.45... control storage vessel regulated material emissions by using an external floating roof converted into an...

  2. 40 CFR 65.44 - External floating roof (EFR).

    Science.gov (United States)

    2010-07-01

    ... Section 65.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Storage Vessels § 65.44 External floating roof (EFR). (a) EFR design requirements. The owner or operator who elects to control storage vessel regulated material...

  3. The Design of Drainage System for External Floating Roof Tank in International Stockpile Project%浅谈国际储备库浮顶排水系统的设计选用

    Institute of Scientific and Technical Information of China (English)

    谭可昕

    2012-01-01

    Large external floating roof storage tank is widely used in petroleum,chemical,civil construction,transportation,metallurgy,national defense and other important fields.Central drainage system is the main accessory for external floating roof tank,its analysis and comparison of structure and type are important for the tank design.The paper summarized the design of central drainage system for external floating roof tank in international stockpile project.%大型外浮顶储罐广泛应用于石油、化工、市政建设、交通、冶金、国防等领域。中央排水系统是外浮顶罐的主要附件,其结构类型的分析和比较是储罐设计中的重要问题。文章综述了在国内一国际储备库项目中,外浮顶罐中央排水系统的设计选用。

  4. Lightning Protection of Floating Roof Tanks

    Directory of Open Access Journals (Sweden)

    Adekitan,

    2013-10-01

    Full Text Available Prior to export, processed crude oil is stored in Floating Roof Tanks (FRT to further allow any trapped gas within the crude oil to escape, as this stabilises the crude oil. In the oil and gas industry, FRT’s are vital in the processing of crude oil to the acceptable export specification.In the tropics and other lightning prone regions, lightning induced floating roof tank fire constitutes a major threat to crude oil production. Among others, a single lightning incident could result in the loss of life, product and production time, avoidable incident review time, damaged equipment, wasted repair cost, bad publicity and loss of income.This paper therefore, is aimed at providing an effective solution to the menace of lightning induced tank fire by focussing on the starting process of the lightning induced fire and proposing alternative concepts for breaking the fire triangle before fire ensues

  5. 用于外浮顶油罐的BSMF型二次密封%BSMF TYPE SECONDARY SEAL FOR USE IN EXTERNAL FLOATING ROOF OIL TANK

    Institute of Scientific and Technical Information of China (English)

    方小芳; 姚定湘; 刘宗良

    2001-01-01

    石油及其产品在储存过程中的蒸发损耗,不仅造成油品数量的损失和环境污染,还导致油品质量的下降和增加不安全因素,因此对储油罐的密封是人们一直关注的问题。用于外浮顶油罐的二次密封,可以弥补一次密封的不足而使油品蒸发降低,大大减轻油气对环境造成的污染和减小不安全因素,并可保护一次密封免受阳光、雨雪、风沙的影响,从而保证储存油品的质量。%During the process of storage for petroleum and itsproduction,the evaporation loss not only makes the oil quanlity loss and envoriment pollution,but also makes the oil quality decrease and increase the unsafe factors.So the seal of oil tank is a problem with general great interesting.The secondary seal for the use of external floating roof oil tank may remedy the defect of fist seal,and makes oil evaporation decrease,So the envoroment pollution,caused by oil gas,reduces and the unsafe factors decrease.It can protects the first seal against the enfluence of sun light,rain and snow,wind and sand,and secure the quality of storage oil.

  6. 40 CFR 63.1043 - Standards-Separator floating roof.

    Science.gov (United States)

    2010-07-01

    ...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1043 Standards... controlling air emissions from an oil-water separator or organic-water separator using a floating roof. (b... floating roof shall be equipped with two continuous seals, one above the other, between the wall of...

  7. Calculus of evaporation losses in oil products in fixed and floating roof tanks after API examples

    Energy Technology Data Exchange (ETDEWEB)

    Barus, D.

    1971-06-01

    From vapor pressure diagrams for products between 1 and 20 psi Reid vapor pressure and for crude oil, the author calculates the evaporation losses through daily breathing, due to temperature fluctuations and through variations in liquid level due to filling and emptying the reservoir, both for fixed roof and for floating roof tanks. The necessary tables, graphs, and nomograms are given. It is concluded that floating roof tanks have a much lower rate of loss through evaporation than fixed roof tanks. The data are based on API publications.

  8. Externalities, Floating Population and Spatial Agglomeration

    Institute of Scientific and Technical Information of China (English)

    Du Yu; Wang Chuansheng; Fan Jie

    2007-01-01

    With the further development of socialist market economy,the mobility of factor markets in China,especially the labor market.is strengthened.Extemalities interacts with the agglomeration of productive factors.Under the framework of new economic geographg this article presents a theoretical model involving the endogenous population density affected by urban externalities.Results show that the population density is more concentrated around the center because the degree and extent of interaction between individuals intensifies when the distance from the center decreases.When there are several extemalifies resonurces,the aggregation of externalities changes the configuration of spatial factor allocation.These results fit well with the empirical facts about the decreasing density of floating population along the cities of Guangzhou,Dongguan and Shenzhen in Guangdong Province which is situat d in the eastern coast of the Pearl River Delta.We find that under the impacts of externalities released from Hong Kong into the coast,floating population Was more concentrated around Shenzhen and Dongguan,which are more adjacent to Hong Kong compared with Guangzhou City.

  9. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... specific information is available, these factors can be assumed to represent the most common bolted...

  10. Floating-roof steel tanks under harmonic settlement: FE parametric study and design criterion

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Large vertical steel tanks for fluid storage are usually constructed on soft foundations, so it is not surprising that the tank wall will settle unevenly with the settlement of the foundation, thus inducing deformations and stresses in the tank. This work investigates the linear static behavior of floating-roof tanks under harmonic settlement through finite element (FE) analyses. The influences of the radius-to-thickness ratio, the height-to-radius ratio and the wind girder stiffness on the structural behavior are first analyzed. Comparisons between the circumferential stresses in the wind girder and the vertical stresses in the tank bottom are then made. The displacement and the stress along the tank height are also discussed, and the concept of tank division along its height is presented. Finally, a design approximation for the radial displacement at the tank top is developed based on FE results, and a settlement criterion based on the top radial displacement is proposed which can be used in practical design.

  11. Total heat loss coefficient of flat roof constructions with external insulation in tapered layers including the effects of thermal bridges

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    and insulation has to be fulfilled. Based on a given design of the tapered insulation the total heat loss coefficient of the roof can be calculated using formulae in EN ISO 6946 for typical segments of the tapered insulation. Performing design and calculations for large roofs with numerous different segments can...... for design of flat roofs and a pc-program that can be used for calculating the total heat loss coefficient of externally insulated roofs with insulation in tapered layers, taking into account thermal bridges in the roof construction.......In order to achieve durability of flat roofs with external insulation, it is necessary to secure proper drainage of the roof, i.e. to avoid water leaking into the insulation. The design of the tapered insulation of the roof is quite difficult as requirements with respect to both drainage...

  12. A novel method to design water spray cooling system to protect floating roof atmospheric storage tanks against fires

    Directory of Open Access Journals (Sweden)

    Iraj Alimohammadi

    2015-01-01

    Full Text Available Hydrocarbon bulk storage tank fires are not very common, but their protection is essential due to severe consequences of such fires. Water spray cooling system is one of the most effective ways to reduce damages to a tank from a fire. Many codes and standards set requirements and recommendations to maximize the efficiency of water spray cooling systems, but these are widely different and still various interpretations and methods are employed to design such systems. This article provides a brief introduction to some possible design methods of cooling systems for protection of storage tanks against external non-contacting fires and introduces a new method namely “Linear Density Method” and compares the results from this method to the “Average Method” which is currently in common practice. The average Method determines the flow rate for each spray nozzle by dividing the total water demand by the number of spray nozzles while the Linear Density Method determines the nozzle flow rate based on the actual flow over the surface to be protected. The configuration of the system includes a one million barrel crude oil floating roof tank to be protected and which is placed one half tank diameter from a similar adjacent tank with a full surface fire. Thermal radiation and hydraulics are modeled using DNV PHAST Version 6.53 and Sunrise PIPENET Version 1.5.0.2722 software respectively. Spray nozzles used in design are manufactured by Angus Fire and PNR Nozzles companies. Schedule 40 carbon steel pipe is used for piping. The results show that the cooling system using the Linear Density Method consumes 3.55% more water than the design using the average method assuming a uniform application rate of 4.1 liters per minute. Despite higher water consumption the design based on Linear Density Method alleviates the problems associated with the Average Method and provides better protection.

  13. Total heat loss coefficient of flat roof constructions with external insulation in tapered layers including the effects of thermal bridges

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    be quite tedious, and therefore a method to generate and optimize solutions has been developed and implemented in a program that also takes into account the effects of different types of thermal bridges, i.e. roof windows, insulation fasteners, roof/wall joints etc. This paper describes a new method...... for design of flat roofs and a pc-program that can be used for calculating the total heat loss coefficient of externally insulated roofs with insulation in tapered layers, taking into account thermal bridges in the roof construction....

  14. Mechanical Cleaning Technology Application in Inner Floating Roof Tank%机械清洗在内浮顶油罐中的应用

    Institute of Scientific and Technical Information of China (English)

    冯杰; 王延昌; 李志国; 程曦; 邱冬

    2013-01-01

    Mechanical cleaning technique of storage tank is relatively advanced one in recent years .It is suitable for floating roof ,vault ,horizontal ,spherical tank cleaning ,with advantages of safety ,environmental protection ,and high efficiency . The mechanical cleaning of the con-struction process and key parameters control are introduced , the risk and control measures in cleaning process are listed .Combined with the cleaning of the floating roof tank of a loading sta-tion south 1# ,the inner floating roof tank mechanical cleaning of the deficiencies and improve-ment measures are analyzed .%  储油罐的机械清洗技术是目前比较先进的储罐清洗技术,适用于浮顶、拱顶、卧式、球形罐的清洗,具有安全、环保、高效等优点。介绍了机械清洗的施工过程及关键参数控制,列举出清洗过程中存在的风险及控制措施,结合某装车站南区1#内浮顶罐的清洗情况,分析了内浮顶罐机械清洗存在的不足及改进措施。

  15. 内浮顶储罐雷击电位分布及危险性%Lightning potential distribution for internal floating roof tanks and its hazards

    Institute of Scientific and Technical Information of China (English)

    高鑫; 刘全桢; 刘宝全; 胡海燕; 毕晓蕾; 姜辉

    2013-01-01

    为了研究内浮顶储罐各金属部件间的电位分布及影响因素,进而明确雷击时储罐的放电部位及预防措施,建立了内浮顶储罐模型,开展了内浮顶储罐雷击模拟试验,获得了储罐各部位电压分布、导静电线电流流向等试验数据.结果表明:在雷电冲击时,无雷电流通过导静电线,浮盘与罐顶连接处电位相同,储罐整体电位可达上百千伏,易对储罐未进行等电位连接的金属部件放电,并引发事故.基于此,可以通过降低储罐的接地电阻降低储罐雷击时的电位,做好等电位连接可消除雷击储罐火灾事故的发生.研究结果对内浮顶储罐雷电防护措施的改进具有一定的指导意义.%In this paper, a model for internal floating roof tank is established to study the potential distribution on various metal components of internal floating roof tank and its influencing factors, and thus discharge locations of the tank and preventive measures are determined in case of lightning, and the experimental data of potential distribution on different locations of the storage tank and the current flow direction of discharge cable through performing lightning simulation test of internal floating roof tank are obtained. The results show that in the case of a lightning surge, there is no current passing through the static electricity discharge cable, thus the potentials of floating disc and tank top are the same, the overall potential of the tank can be up to hundreds of kilovolts, which will easily cause discharging to metal components that are not in equipotential connection and thus led to accidents. Based on this conclusion, the reduction of earthing resistance can decrease the potential of storage tank in case of lightning, and equipotential connection can eliminate the occurrence of fire accidents of the tank due to lightning. These research results have certain instructive significance for improving lightning protection measures of internal

  16. Determination of hydrocarbonemissions from floating roof tanks/follow up. Measurements after 5 years of operation; Ermittlung von Kohlenwasserstoffemissionen aus Schwimmdachtanks/Fortschreibung. Messungen nach 5 Jahren Betriebszeit

    Energy Technology Data Exchange (ETDEWEB)

    Altmann, B.R. [Deutsche Wissenschaftliche Gesellschaft fuer Erdoel, Erdgas und Kohle e.V., Hamburg (Germany); Biernath-Wuepping, S. [IGU - Institut fuer Gewaesserschutz und Umgebungsueberwachung Dr. Biernath-Wuepping GmbH, Kiel (Germany); Weitzel, T. [MERO Pipeline GmbH, Vohburg (Germany)

    2002-03-01

    In addition to the calculation of emissions, it had been decided in the process of the approval for the MERO tank depot in Vohburg (Germany), that measurements of total hydrocarbons and benzene emissions had to be carried out on one of the four floating roof tanks, directly after commissioning as well as after about five years of operation. Following commissioning the measurements and calculations of emissions were carried out in 1996 and published in the DGMK research report 515 'Determination of hydrocarbon emissions from floating roof tanks'. In September 2001, the measurements were repeated after 5 years of operation. As determined in 2001 the concentrations of hydrocarbons contained in the air which moves to or from the tank proved to be close to the limit of evidence of the measuring devices or insignificantly increased (1 ppm). They were in the same order of magnitude as those of 1996. Thus the results show that the emission behaviour did not deteriorate during the time of operation, provided the floating roof seals are well maintained. (orig.) [German] Im Zuge des Genehmigungsverfahrens fuer das MERO-Tanklager in Vohburg wurde festgelegt, zusaetzlich zu den Emissionsberechnungen Emissionsmessungen (Gesamt-Kohlenwasserstoffe, Benzol) an einem der vier Schwimmdachtanks nach Inbetriebnahme und nach etwa fuenf Jahren Betriebszeit durchzufuehren. Die Emissionsmessungen und Emissionsberechnungen nach Inbetriebnahme wurden 1996 durchgefuehrt und im DGMK-Forschungsbericht 515 'Ermittlung der Kohlenwasserstoffemissionen aus Schwimmdachtanks' veroeffentlicht. Im September 2001 fanden die Wiederholungsmessungen nach 5 Jahren Betriebszeit statt. Im Vergleich zu den 1996 ermittelten geringen Kohlenwasserstoffgehalten in der den Tank an - und vom Tank wegstroemenden Luft wurden in 2001 wiederum nur Gehalte um die Messgeraetenachweisgrenze oder geringfuegig erhoeht (1 ppm) gemessen. Die Ergebnisse zeigen, dass bei gut gewarteten Schwimmdach

  17. SEAL AND SEAL DEVICE OF FLOATING ROOF OIL TANK%浮顶油罐的密封及密封装置

    Institute of Scientific and Technical Information of China (English)

    张晓东; 陈建平

    2001-01-01

    During the process of oil storage and transport,not only made thequantity loss,but also made the quality decreasing. Many methods were adopted,among them the most effective method was the application of floating roof.The floating roof roller frame seal thchnology developed at home realized dual seal and had the advantages of good adaptability,large sealing force,small friction force and multi-function combination etc.after put into operation,relative good economic benifit and social effect wew achieved.%油品在储存和转运过程中,不仅造成数量的损失,还会导致油品质量的下降。为此,人们采取了许多方法,其中最有效的方法是浮顶的应用。国内开发的浮顶滚轮骨架密封技术,实现了双重密封且具备适应性强、密封力大、摩擦力小及多功能组合等优点。投用后,获得了较好的经济效益和社会效益。

  18. Time Domain Simulation of Transient Responses of Very Large Floating Structures Under Unsteady External Loads

    Institute of Scientific and Technical Information of China (English)

    QIU Liu-chao; LIU Hua

    2005-01-01

    A time domain finite element method (FEM) for the analysis of transient elastic response of a very large floating structure (VLFS) subjected to arbitrary time-dependent external loads is presented. This method is developed directly in time domain and the hydrodynamic problem is formulated based on linear, inviscid and slightly compressible fluid theory and the structural response is analyzed on the thin plate assumption. The time domain finite element procedure herein is validated by comparing numerical results with available experimental data. Finally, the transient elastic response of a pontoon-type VLFS under the landing of an airplane is computed by the proposed time domain FEM. The time histories of the applied force and the position and velocity of an airplane during landing are modeled with data from a Boeing 747-400 jumbo jet.

  19. 三向地震激励下立式浮顶储罐隔震数值分析%Base isolation numerical analysis of vertical storage tanks with floating roof under three dimensional excitation

    Institute of Scientific and Technical Information of China (English)

    孙颖; 崔利富; 孙建刚; 赵颖华

    2011-01-01

    To reduce seismic response of vertical storage tanks under three dimensional excitation,a 15×104 m3 storage tank was selected as research object,the base isolation system was introduced,allowing the impact of floating roof.Considering the liquid-solid coupling,the finite element analysis model of floating roof storage tank was established by using ADINA.The seismic response of vertical storage tank was analyzed by using Newmark numerical method.Results show that as the inertia mass,the floating roof can effectively control the sloshing wave height,but the base isolation can not effectively control the sloshing wave height.The sloshing wave height is not affected by bi-dimensional and three-dimensional excitation,thus it can be calculated as single dimensional seismic action.The three-dimensional earthquake action should be considered in vertical storage tank earthquake resistance design because of its maximum response under three-dimensional excitation.The base isolation has not significant control effect on the aspects of dynamic pressure and stress of floating roof.%为降低立式浮顶储罐三维地震激励下的地震响应,以15万m3立式浮顶储罐为研究对象,引入基础隔震措施,考虑液固耦合和浮顶参与振动,应用ADINA建立浮顶储罐有限元分析模型,采用Newmak数值方法进行地震响应分析.结果表明:浮顶作为惯性质量具有控制晃动波高的作用,基础隔震不能有效控制储罐晃动波高;双向与三向地震激励对晃动波高影响不大,晃动波高可按单向地震作用计算;三向地震激励作用下储罐地震响应最大,储罐抗震减震设计时应考虑三向地震作用;基底隔震对浮顶的动液压力及应力无很好的控制作用.

  20. 大型立式浮顶储罐基础隔震数值研究%Numerical research on large base isolation vertical storage tanks with floating roof

    Institute of Scientific and Technical Information of China (English)

    孙颖; 孙建刚; 崔利富

    2011-01-01

    The vertical storage tanks with floating roof are usually badly damaged in the strong earthquake. In order to reduce seismic response of vertical storage tanks, selecting 15 x 104m3 storage tank, the base isolation system was introduced and allowing for the impact of floating roof. Based on potential fluid theory, the finite element models were established by using ADINA. The seismic response of base isolation vertical storage tank with different factors such as isolation layer damping ratio, isolation periods, different site conditions and seismic intensity were calculated and comparativey analyzed. The results indicate that when isolation layer damping ratio close to 0.2 ~0. 3 the effect of seismic isolation is best and there is a reasonable range of damping ratio optimization . The vibration reduction rate of base isolation vertical storage tanks with floating roof increases with the increase of isolation period and seismic intensity. Site conditions have a big influence on the vibration neduction effect of base isolation vertical storage tanks with floating roof. Isolation measures can not effectively control the sloshing wave height. Isolation earthquake design of storage tanks with floating roof must consider a variety of factors and select the best isolation design parameters.%强震作用下,立式浮顶储罐破坏严重.为了降低浮顶储罐的地震响应,选取15×104m3大型立式浮顶储罐,引入基础隔震措施,并考虑浮顶的影响,应用势流体理论,采用ADINA建立有限元模型.研究在不同隔震层阻尼比、不同隔震周期、不同烈度及不同场地条件影响下,基础隔震浮顶储罐的地震响应并进行对比分析.结果表明:当隔震层阻尼比为0.2 ~0.3时减震效果较好,阻尼比存在合理优化区间;随着隔震周期、地震烈度的增加,基础隔震浮顶储罐的减震率增加;基础隔震浮顶储罐的减震效应受场地条件影响较大;基础隔震措施不能有效控制浮顶

  1. Pitch Angle Regulation of Floating Wind Turbines with Dynamic Uncertainty and External Disturbances

    Directory of Open Access Journals (Sweden)

    Najah F. Jasim

    2015-06-01

    Full Text Available This paper addresses the problem of pitch angle regulation of floating wind turbines with the presence of dynamic uncertainty and unknown disturbances usually encountered in offshore wind turbines, where two control laws are derived for two different cases to continuously achieve zero pitch angle for the floating turbine. In the first case, the timevarying unknown coefficients that characterize the turbine's dynamics are assumed reasonably bounded by known functions, where robust controller is designed in terms of these known functions to achieve zero pitch angle for the turbine with exponential rate of convergence. While in the second case, the turbine's dynamics are considered to be characterized by unknown coefficients of unknown bounds. In this case, a slidingmode adaptive controller is constructed in terms of estimated values for the unknown coefficients, where these values are continuously updated by adaptive laws associated with the proposed controller to ensure asymptotic convergence to zero for the turbine's pitch angle. Simulations are performed to demonstrate the validity of the proposed controllers to achieve the required regulation objective.

  2. Green roofs

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2010-04-01

    Full Text Available Green roofs are roofs that have been covered with a growing medium, creating a habitat on what would otherwise be a bland, lifeless surface. It is for this reason that green roofs are sometimes call 'vegetated' or 'living' roofs (Cantor 2008). A...

  3. Analysis on Second Sealing Oil and Gas Space Discharge in Floating Roof Tank%浮顶储罐二次密封油气空间放电分析

    Institute of Scientific and Technical Information of China (English)

    胡海燕; 刘宝全; 刘全桢; 张婷婷; 高鑫

    2011-01-01

    In order to avoid floating roof tank sealing ring fire caused by shunts discharge in the second sealing oil and gas space due to lightning, this paper established a 2 m diameter tank model and carried out a shunts spark discharge experiment and an air gap breakdown discharge experiment, so as to systematically research shunts discharge risk in the second sealing oil and gas space.Experimental results show that Shunts attached to the shell by its own flexibility can generate sparks when the lighting current flow reaches a peak of about 400 Amperes; If there are gaps between shunts and the shell during lightning high voltage stock, potential difference between the roof and shell may break down the gaps and cause sparks,when the gap between 20 -30 mm, discharging voltage is about 26 -40 kV.Therefore, shunts spark discharge is inevitable as tank suffering from lightning.Finally, combined with the actual operation of the storage tanks, improvement measures were put forward, such as canceling shunts on the second seal and submerged paraffin scraper device reliable electrical connection with floating roof and avoiding shunts discharge in the second sealing oil and gas space, so as to greatly reduce floating roof tank lightning fire accident.%为避免浮顶储罐在遭受雷击时由于导电片设施在二次密封油气空间中放电引起密封圈火灾,在实验室建立了2 m直径油罐模型,开展导电片火花放电起始电流试验、导电片与罐壁形成空气间隙击穿放电初始电压试验,系统研究导电片在二次密封油气空间中的放电危险性.试验结果表明:导电片靠自身弹性与罐壁贴合时,雷电流大约在400 A时导电片开始产生点燃性火花放电;如导电片与罐壁贴合不良形成空气间隙,雷击情况下雷电流泄放瞬时浮顶与罐壁之间的电位差足以使一定大小的间隙击穿放电,当间隙大小为20~30 mm时,放电电压为26~40 kV.因此,储罐在遭受雷击时,导电片火

  4. 周期性边界条件对浮顶储罐原油传热过程的影响规律%Effect of periodic boundary conditions on heat transfer process of crude oil in floating roof storage tank

    Institute of Scientific and Technical Information of China (English)

    孙巍; 成庆林; 王沛迪; 李玉春; 孙海英

    2016-01-01

    application of a 10×104 m3 floating roof storage tank in Daqing has shown that the temperature drop rate increases with the decrease of the solar radiation intensity and the atmospheric temperature. The effect of solar radiation on temperature drop rate of tank shell is small, which increases with the decrease of atmospheric temperature. The tank bottom is approximate to adiabatic state and the effect of the external environment on temperature drop rate is small. The results can provide theoretical support to optimize the storage process design and manufacturing management of large floating roof tanks.

  5. Roof assembly

    CSIR Research Space (South Africa)

    De Villiers, A

    2010-01-01

    Full Text Available The objective of this chapter is to provide sustainability criteria for roof system design that can be used by planners, designers and developers as a planning, design and development guide for sustainable building projects....

  6. Green Roofs

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-08-01

    A New Technology Demonstration Publication Green roofs can improve the energy performance of federal buildings, help manage stormwater, reduce airborne emissions, and mitigate the effects of urban heat islands.

  7. Understanding Roofing Systems.

    Science.gov (United States)

    Michelsen, Ted

    2001-01-01

    Reviews the various types of multi- and single-ply roofing commonly used today in educational facilities. Roofing types described involve built-up systems, modified bitumen systems; ethylene propylene diene terpolymer roofs; and roofs of thermoplastic, metal, and foam. A description of the Roofing Industry Educational Institute is included. (GR)

  8. New roof element system

    DEFF Research Database (Denmark)

    Ditlev, Jesper; Rudbeck, Claus Christian

    1997-01-01

    The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs.......The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs....

  9. Renovation of Roof Structure

    DEFF Research Database (Denmark)

    Kjærbye, Per Oluf H

    1997-01-01

    A 30 year old not-watertight roof based on wooden boards with roofing felt have been changed to a pitched structure with cementos plates. At the same time more thermal insulation has been placed.......A 30 year old not-watertight roof based on wooden boards with roofing felt have been changed to a pitched structure with cementos plates. At the same time more thermal insulation has been placed....

  10. New roof element system

    DEFF Research Database (Denmark)

    Ditlev, Jesper; Rudbeck, Claus Christian

    1997-01-01

    The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs.......The aim of the project has been to develop an element system for warm deck roofs which, from a thermal and economical point of view, can deal with the future demands for heat loss coefficients for low slope roofs....

  11. Green roof Malta

    OpenAIRE

    2015-01-01

    In Malta, buildings cover one third of the Island, leaving greenery in the dirt track. Green roofs are one way to bring plants back to urban areas with loads of benefits. Antoine Gatt, who manages the LifeMedGreenRoof project at the University of Malta, tells us more. http://www.um.edu.mt/think/green-roof-malta/

  12. EPA's Green Roof Research

    Science.gov (United States)

    This is a presentation on the basics of green roof technology. The presentation highlights some of the recent ORD research projects on green roofs and provices insight for the end user as to the benefits for green roof technology. It provides links to currently available EPA re...

  13. FLOAT Project

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Aarup, Bendt

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach a commercial breakthrough, wave energy converters need to achieve a lower price...... of energy produced, comparable to prices currently obtained from offshore wind power, and this can be done by the use of more suitable materials. The flotation device is a key part of converters, as it accounts for a considerable share of initial investment, up to 27% depending on the converter. CRC floats...

  14. IMPROVED ROOF STABILIZATION TECHNOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    M.A. Ebadian, Ph.D.

    1999-01-01

    Many U.S. Department of Energy (DOE) remediation sites have performed roof repair and roof replacement to stabilize facilities prior to performing deactivation and decommissioning (D&D) activities. This project will review the decision criteria used by these DOE sites, along with the type of repair system used for each different roof type. Based on this information, along with that compiled from roofing experts, a decision-making tool will be generated to aid in selecting the proper roof repair systems. Where appropriate, innovative technologies will be reviewed and applied to the decision-making tool to determine their applicability. Based on the results, applied research and development will be conducted to develop a method to repair these existing roofing systems, while providing protection for the D and D worker in a cost-efficient manner.

  15. Floating Life

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ One in six people in China have left their hometown in search of a better life and the number continues to grow,creating a challenge for host cities,according to a government report.The floating population,or people who live and work outside their permanent home,reached 211 million last year and the number could reach 350 million by 2050 if govemment policies remain unchanged,said the Report on the Development of China's Floating Population issued on June 26 by the National Population and Family Planning Commission (NPFPC).

  16. Collaborative active roof design

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.

    2008-01-01

    Roofs play an essential role in buildings. Their value and impact often significantly surpass the cost ratio they represent in the total investment cost of the building. Traditionally, roofs have a protecting function and their basic design has changed little over hundreds of years. Nowadays

  17. Simulation for the Thermal Response of Crude Oil in Large Floating Roof Tank Subjected to Fire Environmen%火灾环境下大型浮顶罐内原油热响应行为的仿真模拟

    Institute of Scientific and Technical Information of China (English)

    宋文华; 李庆功; 冯莉莉; 陈阵

    2012-01-01

    采用FLUENT软件对设定罐壁接受辐射值为25 kW/m2情况下的原油储罐进行模拟.模拟的主要结果包括油罐受热后罐内流体的温度、流速、压力的分布情况.在火灾作用下,罐内原油由于热量传递的不均匀而发生对流,靠近罐壁的流体流速较大,最大流速为0.026 439 17 m/s;油罐内罐壁附近处油温最高,可达150℃,并随指向轴线的方向逐渐降低.罐内原油受热挥发迅速,罐内压力增大,会导致罐体浮盘掀开或罐体坍塌,形成蒸气云爆炸事故与防火堤内池火灾事故,同时还伴随着发生原油沸扬事故的危险.%The safety of large floating roof tank is always the focus of safety work. Once the tank area occurs fire accident, the main way of the disaster spread is heat radiation and heat shock, so the thermal response of crude oil tank which near the accident site is very important. FLUENT software was used to simulate crude oil storage tank, setting thermal radiation strength value to 25 kW/m2. The main simulation results include the temperature, flow rate and pressure distribution of the fluid in the heating oil tank. Under the action of the fire, the crude oil in tank occurs convection because of the uneven heat transfer, the fluid near the tank wall has a larger flow rate, the maximum flow rate is 0. 026 439 17 m/s. The oil near the inner wall has the highest temperature which can reach about 150 ℃ , and gradually decreases with the pointing direction of the axis. The crude oil in tank volatilize quickly and the pressure in tank increases. This can cause the tank floating tray open or tank collapse and it maybe form vapor cloud explosion and pool fire accident in fire embankment, and it also has a crude oil sweeping accident risk.

  18. Mine roof supports

    Energy Technology Data Exchange (ETDEWEB)

    Dettmers, M.; Peters, B.; Weirich, W.

    1983-12-27

    A mine roof support has hydraulic props mounted between a floor sill and a roof bar which can be raised and lowered by extension and retraction of the props. A goaf shield is pivotably connected to the rear of the roof bar and is linked via levers to the floor sill. A hydraulic piston and cylinder unit is connected between the roof bar and the goaf shield. Apparatus serves to prevent damage to the support components, and especially to the unit which could be extended beyond its full stroke when the props are retracted to bring the goaf shield and the roof bar more or less into alignment. The protective apparatus is composed of a compact valve device operated by a member, such as a cam, to block the props from hydraulic pressure when the goaf shield and the roof bar assume a pre-determined angular disposition. Both the valve device and its operating member are disposed in a protected position within chambers formed inside the roof bar and the goaf shield adjacent the pivot connection therebetween.

  19. Norwegian Pitched Roof Defects

    Directory of Open Access Journals (Sweden)

    Lars Gullbrekken

    2016-06-01

    Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

  20. Adaptable typologies for active roofs

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.; Zeiler, W.

    2006-01-01

    The main objective of this part of the 6th framework Pan-European EUR-ACTIVE ROOF-er project is to improve the interaction between design participants of dynamic adaptable Active Roofs in product development and Active Roofs from an architects/ customers perspective. Improvements in Active Roof desi

  1. Green Roofs for Stormwater Management

    Science.gov (United States)

    This project evaluated green roofs as a stormwater management tool. Results indicate that the green roofs are capable of removing 40% of the annual rainfall volume from a roof through retention and evapotranspiration. Rainfall not retained by green roofs is detained, effectively...

  2. Green roofs; Les toitures vegetalisees

    Energy Technology Data Exchange (ETDEWEB)

    Seghier, C.

    2006-03-15

    Impervious surface coverage keeps spreading in cities. Streets, sidewalks, parking lots and roofs are waterproof, meaning greater amounts of water to channel and treat and higher flood risks during heavy rainfalls. Green roofing can play a key part in addressing this alarming issue. There are three types of green roofs: extensive, semi-intensive and intensive. The extensive green roof technique uses a thin soil covering with a variety of species providing year-round plant coverage. The plants are not necessarily horticultural in which case routine maintenance is minimal. No watering is needed. Usually extensive green roofs create an ecosystem. The semi-intensive green roof technique uses a soil covering of average thickness and serves to create decorative roofing. Although maintenance is moderate, watering is essential. The intensive green roof technique produces a terrace roof garden. Another advantage of green roofs is they increase the life cycle of the sealing. Roof sealing protection may see the span of its life cycle, now at about fifteen years, doubled if the building has a green roof. planning professionals still know very little about green roofing solutions. Yet, green roofing provides unquestionable ecological qualities and thermal and acoustic performance that have proven to be environmentally friendly. Yet France lags behind northern European countries in green roofing. The Germans, Swiss, Austrians, Scandinavians and Dutch have been using the technique for more than twenty years. (A.L.B.)

  3. Floating shoulder

    OpenAIRE

    B. de Pablo Márquez; P. Castillón Bernal; I. Fuentes López

    2014-01-01

    La fractura concomitante de clavícula y escápula es una entidad poco frecuente que puede ser una de las causas de afectación del complejo suspensorio del hombro también denominado hombro flotante (floating shoulder). Se relaciona frecuentemente con traumatismos de alta energía. Presentamos un caso de esta patología en un paciente varón de 28 años que consultó por caída en bicicleta con contusión sobre hombro izquierdo. Se describen las diferentes opciones terapéuticas planteadas, las imágenes...

  4. Green Roofs for Stormwater Runoff Control - Abstract

    Science.gov (United States)

    This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

  5. Floating shoulder

    Directory of Open Access Journals (Sweden)

    B. de Pablo Márquez

    2014-09-01

    Full Text Available La fractura concomitante de clavícula y escápula es una entidad poco frecuente que puede ser una de las causas de afectación del complejo suspensorio del hombro también denominado hombro flotante (floating shoulder. Se relaciona frecuentemente con traumatismos de alta energía. Presentamos un caso de esta patología en un paciente varón de 28 años que consultó por caída en bicicleta con contusión sobre hombro izquierdo. Se describen las diferentes opciones terapéuticas planteadas, las imágenes radiológicas y una revisión de la literatura.

  6. Evolution of Flat Roofs

    Directory of Open Access Journals (Sweden)

    Şt. Vasiliu

    2009-01-01

    Full Text Available Roofs are constructive subassembles that are located at the top of buildings, which toghether with perimetral walls and some elements of the infrastructure belongs to the subsystem elements that close the building. Roofs must meet resistance requirements to mechanical action, thermal insulating, waterproofing and acoustic, fire resistance, durability, economy and aesthetics. The man saw the need to build roofs from the oldest ancient times. Even if the design of buildings has an empirical character, are known and are preserved until today constructions that are made in antiquity, by the Egyptians, Greeks and Romans with architectural achievements, worthy of admiration and in present time. General composition of civil construction has been influenced throughout the evolution of construction history by the level of production forces and properties of building materials available in every historical epoch. For over five millennia, building materials were stone, wood and ceramic products (concrete was used by theRomans only as filling material.

  7. Design methodology for innovative roofs

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.; Zeiler, W.; Trum, H.M.G.J.

    2006-01-01

    Traditional roofs have primary, passive, functions such as protection against rain, wind, snow etc.. Nowadays, roofs are increasingly used as preferred location for additional functions such as photovoltaic systems, roof lights and safety devices. New approaches, on designing as well as assembling t

  8. Summer Thermal Performance of Ventilated Roofs with Tiled Coverings

    Science.gov (United States)

    Bortoloni, M.; Bottarelli, M.; Piva, S.

    2017-01-01

    The thermal performance of a ventilated pitched roof with tiled coverings is analysed and compared with unventilated roofs. The analysis is carried out by means of a finite element numerical code, by solving both the fluid and thermal problems in steady-state. A whole one-floor building with a pitched roof is schematized as a 2D computational domain including the air-permeability of tiled covering. Realistic data sets for wind, temperature and solar radiation are used to simulate summer conditions at different times of the day. The results demonstrate that the batten space in pitched roofs is an effective solution for reducing the solar heat gain in summer and thus for achieving better indoor comfort conditions. The efficiency of the ventilation is strictly linked to the external wind conditions and to buoyancy forces occurring due to the heating of the tiles.

  9. Producing superhydrophobic roof tiles

    Science.gov (United States)

    Carrascosa, Luis A. M.; Facio, Dario S.; Mosquera, Maria J.

    2016-03-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  10. "Floating shoulder" injuries.

    Science.gov (United States)

    Heng, Kenneth

    2016-12-01

    "Floating shoulder" is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.

  11. Stormwater Attenuation by Green Roofs

    Science.gov (United States)

    Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.

    2014-12-01

    Innovative municipal stormwater management technologies are urgently required in urban centers. Inadequate stormwater management can lead to excessive flooding, channel erosion, decreased stream baseflows, and degraded water quality. A major source of urban stormwater is unused roof space. Green roofs can be used as a stormwater management tool to reduce roof generated stormwater and generally improve the quality of runoff. With recent legislation in some North American cities, including Toronto, requiring the installation of green roofs on large buildings, research on the effectiveness of green roofs for stormwater management is important. This study aims to assess the hydrologic response of an extensive sedum green roof in London, Ontario, with emphasis on the response to large precipitation events that stress municipal stormwater infrastructure. A green roof rapidly reaches field capacity during large storm events and can show significantly different behavior before and after field capacity. At field capacity a green roof has no capillary storage left for retention of stormwater, but may still be an effective tool to attenuate peak runoff rates by transport through the green roof substrate. The attenuation of green roofs after field capacity is linked to gravity storage, where gravity storage is the water that is temporarily stored and can drain freely over time after field capacity has been established. Stormwater attenuation of a modular experimental green roof is determined from water balance calculations at 1-minute intervals. Data is used to evaluate green roof attenuation and the impact of field capacity on peak flow rates and gravity storage. In addition, a numerical model is used to simulate event based stormwater attenuation. This model is based off of the Richards equation and supporting theory of multiphase flow through porous media.

  12. Humble Opinion of Roof Gardens

    Institute of Scientific and Technical Information of China (English)

    WANGXiaoxiao; MAQiangqiang; CAOXiaojun

    2005-01-01

    With the swift development of urban construction in China and the boost in people's demands for green environments in cities, roof gardens are widely used as a new way of greening. This paper deals chiefly with the functions, building principle, classification and composing elements of roof gardens, an analysis of main ecological factors, loads, and waterproof. It suggests that roof gardens will bring about a comparatively big leap in city greening both quantitatively and qualitatively.

  13. Cycle graph analysis for 3D roof structure modelling: Concepts and performance

    Science.gov (United States)

    Perera, Gamage Sanka Nirodha; Maas, Hans-Gerd

    2014-07-01

    The paper presents a cycle graph analysis approach to the automatic reconstruction of 3D roof models from airborne laser scanner data. The nature of convergences of topological relations of plane adjacencies, allowing for the reconstruction of roof corner geometries with preserved topology, can be derived from cycles in roof topology graphs. The topology between roof adjacencies is defined in terms of ridge-lines and step-edges. In the proposed method, the input point cloud is first segmented and roof topology is derived while extracting roof planes from identified non-terrain segments. Orientation and placement regularities are applied on weakly defined edges using a piecewise regularization approach prior to the reconstruction, which assists in preserving symmetries in building geometry. Roof corners are geometrically modelled using the shortest closed cycles and the outermost cycle derived from roof topology graph in which external target graphs are no longer required. Based on test results, we show that the proposed approach can handle complexities with nearly 90% of the detected roof faces reconstructed correctly. The approach allows complex height jumps and various types of building roofs to be firmly reconstructed without prior knowledge of primitive building types.

  14. The impact of roofing material on building energy performance

    Science.gov (United States)

    Badiee, Ali

    The last decade has seen an increase in the efficient use of energy sources such as water, electricity, and natural gas as well as a variety of roofing materials, in the heating and cooling of both residential and commercial infrastructure. Oil costs, coal and natural gas prices remain high and unstable. All of these instabilities and increased costs have resulted in higher heating and cooling costs, and engineers are making an effort to keep them under control by using energy efficient building materials. The building envelope (that which separates the indoor and outdoor environments of a building) plays a significant role in the rate of building energy consumption. An appropriate architectural design of a building envelope can considerably lower the energy consumption during hot summers and cold winters, resulting in reduced HVAC loads. Several building components (walls, roofs, fenestration, foundations, thermal insulation, external shading devices, thermal mass, etc.) make up this essential part of a building. However, thermal insulation of a building's rooftop is the most essential part of a building envelope in that it reduces the incoming "heat flux" (defined as the amount of heat transferred per unit area per unit time from or to a surface) (Sadineni et al., 2011). Moreover, more than 60% of heat transfer occurs through the roof regardless of weather, since a roof is often the building surface that receives the largest amount of solar radiation per square annually (Suman, and Srivastava, 2009). Hence, an argument can be made that the emphasis on building energy efficiency has influenced roofing manufacturing more than any other building envelope component. This research project will address roofing energy performance as the source of nearly 60% of the building heat transfer (Suman, and Srivastava, 2009). We will also rank different roofing materials in terms of their energy performance. Other parts of the building envelope such as walls, foundation

  15. Green roofs: potential at LANL

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Elena M [Los Alamos National Laboratory

    2009-01-01

    Green roofs, roof systems that support vegetation, are rapidly becoming one of the most popular sustainable methods to combat urban environmental problems in North America. An extensive list of literature has been published in the past three decades recording the ecological benefits of green roofs; and now those benefits have been measured in enumerated data as a means to analyze the costs and returns of green roof technology. Most recently several studies have made substantial progress quantifying the monetary savings associated with storm water mitigation, the lessoning of the Urban Heat Island, and reduction of building cooling demands due to the implementation of green roof systems. Like any natural vegetation, a green roof is capable of absorbing the precipitation that falls on it. This capability has shown to significantly decrease the amount of storm water runoff produced by buildings as well as slow the rate at which runoff is dispensed. As a result of this reduction in volume and velocity, storm drains and sewage systems are relieved of any excess stress they might experience in a storm. For many municipalities and private building owners, any increase in storm water mitigation can result in major tax incentives and revenue that does not have to be spent on extra water treatments. Along with absorption of water, vegetation on green roofs is also capable of transpiration, the process by which moisture is evaporated into the air to cool ambient temperatures. This natural process aims to minimize the Urban Heat Island Effect, a phenomenon brought on by the dark and paved surfaces that increases air temperatures in urban cores. As the sun distributes solar radiation over a city's area, dark surfaces such as bitumen rooftops absorb solar rays and their heat. That heat is later released during the evening hours and the ambient temperatures do not cool as they normally would, creating an island of constant heat. Such excessively high temperatures induce heat

  16. A School on Roof

    Institute of Scientific and Technical Information of China (English)

    ZhouChao

    2005-01-01

    March 23, Wednesday, Wuhan. It was a raining and cloudy day. One month passed but still more than 20 students had yet registered in Lingzhi Elementary School in Jianghan District, Wuhan, capital city of central Hubei Province. Zhu Zhongfan habitually looked out to the stairway of the building. “Whenever a new semester begins, a dozen of students will not come. They either go back to their hometowns or transfer to other school or even drop out.” Zhu, 49 years old, is the headmaster of the school. He began teaching at 19 and founded this school in 1999. Currently, there are 406 registered students, most of which are children of migrant workers from the countryside. As it is extremely hard to find a cheap place for school, Zhu had to locate his school on the roof of a vegetable fair building. Everyday, student's reciting of textbooks mixes with shouting of vendors, orchestrating unique symphonic melodies.

  17. Sustainable roofs with real energy savings

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.; Petrie, T.W.

    1996-12-31

    This paper addresses the general concept of sustainability and relates it to the building owner`s selection of a low-slope roof. It offers a list of performance features of sustainable roofs. Experiences and data relevant to these features for four unique roofs are then presented which include: self-drying systems, low total equivalent warming foam insulation, roof coatings and green roofs. The paper concludes with a list of sustainable roofing features worth considering for a low-slope roof investment. Building owners and community developers are showing more interest in investing in sustainability. The potential exists to design, construct, and maintain roofs that last twice as long and reduce the building space heating and cooling energy loads resulting from the roof by 50% (based on the current predominant design of a 10-year life and a single layer of 1 to 2 in. (2.5 to 5.1 cm) of insulation). The opportunity to provide better low-slope roofs and sell more roof maintenance service is escalating. The general trend of outsourcing services could lead to roofing companies` owning the roofs they install while the traditional building owner owns the rest of the building. Such a situation would have a very desirable potential to internalize the costs of poor roof maintenance practices and high roof waste disposal costs, and to offer a profit for installing roofs that are more sustainable. 14 refs., 12 figs.

  18. Green Roofs for Stormwater Runoff Control

    Science.gov (United States)

    This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence...

  19. Sustainable roofs with real energy savings

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.; Petrie, T.W.

    1996-12-31

    This paper addresses the general concept of sustainability and relates it to the building owner`s selection of a low-slope roof. It offers a list of performance features of sustainable roofs. Experiences and data relevant to these features for four unique roofs are then presented which include: self-drying systems, low total equivalent warming foam insulation, roof coatings and green roofs. The paper concludes with a list of sustainable roofing features worth considering for a low-slope roof investment. Building owners and community developers are showing more interest in investing in sustainability. The potential exists to design, construct, and maintain roofs that last twice as long and reduce the building space heating and cooling energy loads resulting from the roof by 50% (based on the current predominant design of a 10-year life and a single layer of 1 to 2 in. (2.5 to 5.1 cm) of insulation). The opportunity to provide better low-slope roofs and sell more roof maintenance service is escalating. The general trend of outsourcing services could lead to roofing companies` owning the roofs they install while the traditional building owner owns the rest of the building. Such a situation would have a very desirable potential to internalize the costs of poor roof maintenance practices and high roof waste disposal costs, and to offer a profit for installing roofs that are more sustainable. 14 refs., 12 figs.

  20. 30 CFR 75.205 - Installation of roof support using mining machines with integral roof bolters.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Installation of roof support using mining machines with integral roof bolters. 75.205 Section 75.205 Mineral Resources MINE SAFETY AND HEALTH... Roof Support § 75.205 Installation of roof support using mining machines with integral roof bolters...

  1. Evaluation of energy roof direct utilization

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.; Rossetto, L.; Viero, L.

    1984-04-01

    Energy roofs are roofing systems equipped with channels which allow both solar and atmospheric energy collection. They were conceived as cold source for heat pump systems. The behavious of an energy roof in DHW direct heating was studied; this might extend energy roof utilization all year long. The estimates were performed through more reliable recently proposed correlations for wind convection heat transfer coefficients. The advantage of annual energy roof utilization in DHW direct heating is predictable.

  2. Advanced Energy Efficient Roof System

    Energy Technology Data Exchange (ETDEWEB)

    Jane Davidson

    2008-09-30

    Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The

  3. [A review of green roof performance towards management of roof runoff].

    Science.gov (United States)

    Chen, Xiao-ping; Huang, Pei; Zhou, Zhi-xiang; Gao, Chi

    2015-08-01

    Green roof has a significant influence on reducing runoff volume, delaying runoff-yielding time, reducing the peak flow and improving runoff quality. This paper addressed the related research around the world and concluded from several aspects, i.e., the definition of green roof of different types, the mechanism how green roof manages runoff quantity and quality, the ability how green roof controls roof runoff, and the influence factors of green roof toward runoff quantity and quality. Afterwards, there was a need for more future work on research of green roof toward roof runoff, i.e., vegetation selection of green roof, efficient construction model selection of green roof, the regulating characteristics of green roof on roof runoff, the value assessment of green roof on roof runoff, analysis of source-sink function of green roof on the water pollutants of roof runoff and the research on the mitigation measures of roof runoff pollution. This paper provided a guideline to develop green roofs aiming to regulating roof runoff.

  4. Hydrological Performance of Green Roofs

    OpenAIRE

    Poorova, Zuzana; Vranayova, Zuzana

    2015-01-01

    There should be a balance between artificial environment and natural environment. As forests, fields, gardens and urban lands are being replaced with bituminous, concrete and unnatural surfaces, necessity of recovering green and blue spaces and natural areas is becoming more and more critical. Green roof is a tool in strategy of making more pervious areas and beating more impervious areas. Green roof is lately becoming part of urban storm water management. Considering this fact, new construct...

  5. Economic Floating Waste Detectionfor Surface Cleaning Robots

    Directory of Open Access Journals (Sweden)

    Sumroengrit Jakkrit

    2017-01-01

    Full Text Available Removing waste out of water surface is a routine task and can be operated by using autonomous surface cleaning robots. This paper presents amethodoflaser-based floating waste detection for surface robot guidance when waste positions are unknown beforehand. Basing on concept of refraction and reflection of laser ray, the proposed laser-based technique is proven to be applicable on floating waste detection. The economic waste detector is constructed and mounted on the robot. Five DOF equations of motion are formulated for calculation of waste position incorporating distance measured by the laser and also the robot motion caused by external wind force as well as water surface tension. Experiments were conducted on a pond with calm water and results show that the presented economic waste detection successfully identify and locate position of plastic bottles floating on water surface within the range of 5 meters.

  6. Heat transfer analysis in PCM-filled RCC roof for thermal management

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, PSS [Knowledge Institute of Technology, Salem (India); Mavikumar, M. [Bannariamman Institute of Technology, Sathyamangalam (Iran, Islamic Republic of)

    2014-03-15

    We analyzed of heat transmission across three roof structures ; bare RCC (reinforced cement concrete) roof, RCC roof with weathering coarse and RCC roof with PCM (phase change material) above RCC. A transient numerical procedure was developed. ANSYSFluent 12 finite volume method based software was used for solving the problem. The numerical procedure was validated against the available experimental data. The simulation was carried out on 365 days of the year for these three roofs. The PCM melted from 8 h to 18 h and solidified during the rest of the day. From March to August, the net heat entering into the room per day is positive, thus more and more PCM melts and becomes liquid. The liquid portion of PCM increases from March to August, during September to February, there is a net heat rejection per day, thus the melted PCM becomes solid progressively, and at the end of February, almost all PCM has become solid. Thus there is a melting cycle on a daily basis and over the year. It takes care of all the external climatic variations and keeps the roof bottom surface temperature almost constant and close to room air temperature. On yearly basis, about 56% reduction in heat transmission into the room is obtained with PCM roof when compared to the conventional weathering coarse laid roof.

  7. Summer and Winter Effect of Innovative Cool Roof Tiles on the Dynamic Thermal Behavior of Buildings

    Directory of Open Access Journals (Sweden)

    Anna Laura Pisello

    2014-04-01

    Full Text Available Cool roofs represent an acknowledged passive cooling technique to reduce building energy consumption for cooling and to mitigate urban heat island effects. This paper concerns the evaluation of the dynamic effect of new cool roof clay tiles on building thermal performance in summer and winter conditions. To this end, these properties have been analyzed on traditional roof brick tiles through an indoor and outdoor two-year long continuous monitoring campaign set up in a residential building located in central Italy. The analysis and the cooperation with industrial companies producing brick tiles and reflective coatings allowed the production of a new tile with notable “cool roof” properties through the traditional industrial manufacturing path of such tiles. Notable results show that during summer the high reflection tiles are able to decrease the average external roof surface temperature by more than 10 °C and the indoor operative temperature by more than 3 °C. During winter the average external surface temperature is lower with high reflection tiles by about 1 °C. Singular optic-thermal phenomena are registered while evaluating the dynamics of the cool roof effect. Interesting findings show how the sloped cool roof application could suggest further considerations about the dynamic effect of cool roofs.

  8. Performance Analysis of Cool Roof, Green Roof and Thermal Insulation on a Concrete Flat Roof in Tropical Climate

    OpenAIRE

    Zingre, Kishor T.; Yang, Xingguo; Wan, Man Pun

    2015-01-01

    In the tropics, the earth surface receives abundant solar radiation throughout the year contributing significantly to building heat gain and, thus, cooling demand. An effective method that can curb the heat gains through opaque roof surfaces could provide significant energy savings. This study investigates and compares the effectiveness of various passive cooling techniques including cool roof, green roof and thermal insulation for reducing the heat gain through a flat concrete roof in tropic...

  9. Advanced Energy Efficient Roof System

    Energy Technology Data Exchange (ETDEWEB)

    Jane Davidson

    2008-09-30

    Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned attic. The

  10. Simulated floating zone method

    OpenAIRE

    Ozawa, Ryo; Kato, Yasuyuki; Motome, Yukitoshi

    2016-01-01

    This paper provides the simulated floating zone (SFZ) method that is an efficient simulation technique to obtain thermal equilibrium states, especially useful when domain formation prevents the system from reaching a spatially-uniform stable state. In the SFZ method, the system is heated up locally, and the heated region is steadily shifted, similar to the floating zone method for growing a single crystal with less lattice defect and impurity in experiments. We demonstrate that the SFZ method...

  11. Sloped Roof Conversions for Small, Flat-Roof Buildings.

    Science.gov (United States)

    1984-12-01

    co solve other, unrelated Table 5 List of Contacts Involved in Roof Conversion Projects California AEP-Span, San Diego Florida Duval County...Survlvablllty Section, CCB-CPS Infrastructure Branch, LANDA HQ UsaUCOH 09128 ATTN: ECJ 4/7-LOE Fort Belvoir, VA 22060 (7) ATTN

  12. Green Roof Potential in Arab Cities

    OpenAIRE

    Attia, Shady

    2014-01-01

    Urban green roofs have long been promoted as an easy and effective strategy for beautifying the built environment and increasing investment opportunity. The building roof is very important because it has a direct impact on thermal comfort and energy conservation in and around buildings. Urban green roofs can help to address the lack of green space in many urban areas. Urban green roofs provides the city with open spaces that helps reduce urban heat island effect and provides the human populat...

  13. GREEN ROOFS — A GROWING TREND

    Science.gov (United States)

    One of the most interesting stormwater control systems under evaluation by EPA are “green roofs”. Green roofs are vegetative covers applied to building roofs to slow, or totally absorb, rainfall runoff during storms. While the concept of over-planted roofs is very ancient, the go...

  14. Evaluation of Roof Bolting Requirements Based on In-Mine Roof Bolter Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Syd S. Peng

    2005-10-01

    Roof bolting is the most popular method for underground openings in the mining industry, especially in the bedded deposits such as coal. In fact, all U.S. underground coal mine entries are roof-bolted as required by law. However, roof falls still occur frequently in the roof bolted entries. The two possible reasons are: the lack of knowledge of and technology to detect the roof geological conditions in advance of mining, and lack of roof bolting design criteria for modern roof bolting systems. This research is to develop a method for predicting the roof geology and stability condition in real time during roof bolting operation. Based on this information, roof bolting design criteria for modern roof bolting systems will be developed for implementation in real time. For the prediction of roof geology and stability condition in real time, a micro processor was used and a program developed to monitor and record the drilling parameters of roof bolter. These parameters include feed pressure, feed flow (penetration rate), rotation pressure, rotation rate, vacuum pressure, oil temperature of hydraulic circuit, and signals for controlling machine. From the results of a series of laboratory and underground tests so far, feed pressure is found to be a good indicator for identifying the voids/fractures and estimating the roof rock strength. The method for determining quantitatively the location and the size of void/fracture and estimating the roof rock strength from the drilling parameters of roof bolter was developed. Also, a set of computational rules has been developed for in-mine roof using measured roof drilling parameters and implemented in MRGIS (Mine Roof Geology Information System), a software package developed to allow mine engineers to make use of the large amount of roof drilling parameters for predicting roof geology properties automatically. For the development of roof bolting criteria, finite element models were developed for tensioned and fully grouted bolting

  15. The Girl on the Roof

    Institute of Scientific and Technical Information of China (English)

    刘晓宁; 邓彬

    2003-01-01

    One day when the sun was shin-ning and Jillian's office at the BBCwas getting warm,she had one of her ideas."I'll go up ontothe roof after lunch,"she thought,"andsunbathe(日光浴).I've been working hard

  16. PREDICTING THERMAL PERFORMANCE OF ROOFING SYSTEMS IN SURABAYA

    Directory of Open Access Journals (Sweden)

    MINTOROGO Danny Santoso

    2015-07-01

    Full Text Available Traditional roofing systems in the developing country likes Indonesia are still be dominated by the 30o, 45o, and more pitched angle roofs; the roofing cover materials are widely used to traditional clay roof tiles, then modern concrete roof tiles, and ceramic roof tiles. In the 90’s decay, shop houses are prosperous built with flat concrete roofs dominant. Green roofs and roof ponds are almost rarely built to meet the sustainable environmental issues. Some tested various roof systems in Surabaya were carried out to observe the roof thermal performances. Mathematical equation model from three references are also performed in order to compare with the real project tested. Calculated with equation (Kabre et al., the 30o pitched concrete-roof-tile, 30o clay-roof-tile, 45o pitched concrete-roof-tile are the worst thermal heat flux coming to room respectively. In contrast, the bare soil concrete roof and roof pond system are the least heat flux streamed onto room. Based on predicted calculation without insulation and cross-ventilation attic space, the roof pond and bare soil concrete roof (greenery roof are the appropriate roof systems for the Surabaya’s climate; meanwhile the most un-recommended roof is pitched 30o or 45o angle with concrete-roof tiles roofing systems.

  17. Hydrological Response of Sedum-Moss Roof

    Science.gov (United States)

    Bengtsson, L.

    2004-12-01

    Eco-roofs are becoming popular for aesthetic reasons and also as units of stormwater systems. It is thought that such roofs with soil cover and vegetation reduces the total runoff, the peak flows and improves the quality of the roof water. Here are reported investigations of runoff from thin, 3-4 cm soil, extensive green roofs with sedum-moss in southern Sweden. The two-year study was performed on new roofs in the eco-city Augustenborg and also on nearby old vegetative roofs. The rain intensity and the roof runoff were measured with 5 min, or in some experiments with 1 min, resolution. The annual runoff from the eco-roofs was about half that from hard roofs and was close to that of small natural rivers. However, although most rainy days there was no or little runoff from the roofs, the highest observed daily runoff values were close to the daily rainfall. Runoff is initiated, when the soil is at field capacity. Thereafter the hourly runoff corresponds closely to the hourly rainfall. For short-term high intensity storms, the runoff peak is attenuated relative the rain intensity. The time of concentration for runoff was experimentally determined applying artificial rains on existing roofs and on experimental roof plots with varying slopes and using different drainage layers. The peak runoff from the roofs was found to correspond to the rain intensity over 20-30 minutes. The probability of high rain intensity is much higher than the probability of high runoff. When intensity-duration-frequency curves were constructed, runoff with 0.4 year return period corresponded to rain with 1.5 year return period. The influence of the slope of the roofs on the runoff peak was minor as was the effect of drainage layer. The vertical flow in the soil dominates the runoff process. The influence of extensive sedum-moss vegetated roofs on runoff quality was also studied to ascertain whether vegetated roofs behave as sink or source of pollutants and whether the runoff quality changes

  18. PREDICTING THERMAL PERFORMANCE OF ROOFING SYSTEMS IN SURABAYA

    OpenAIRE

    2015-01-01

    Traditional roofing systems in the developing country likes Indonesia are still be dominated by the 30o, 45o, and more pitched angle roofs; the roofing cover materials are widely used to traditional clay roof tiles, then modern concrete roof tiles, and ceramic roof tiles. In the 90’s decay, shop houses are prosperous built with flat concrete roofs dominant. Green roofs and roof ponds are almost rarely built to meet the sustainable environmental issues. Some tested various roof systems in Sura...

  19. FLOAT Project - Task 1

    DEFF Research Database (Denmark)

    Marchalot, Tanguy; Kofoed, Jens Peter; Sørensen, Eigil V.

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach commercial breakthrough, wave energy converters need to achieve a lower price...... of energy produced, comparable to prices currently obtained from offshore wind power, and this can be done by the use of more suitable materials. The flotation device is a key part of converters, as it accounts for a considerable share of initial investment, up to 27% depending on the converter (dexawave.......com, 2011). CRC floats could be a very cost-effective technology with enhanced loading capacity and environmental resistance, and very low maintenance requirements, affecting directly the final energy price. The project involves DEXA Wave Energy Ltd, Wave Star A/S, Aalborg University and Hi-Con A...

  20. Generating realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2011-01-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs, and show a connection with the straight skeleton of P. We show that the maximum possible number of distinct realistic roofs over P is ( ⌊(n-4)/4⌋ (n-4)/2) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n 4) preprocessing time. We also present an O(n 5)-time algorithm for computing a realistic roof with minimum height or volume. © 2011 Springer-Verlag.

  1. Floating offshore turbines

    DEFF Research Database (Denmark)

    Tande, John Olav Giæver; Merz, Karl; Schmidt Paulsen, Uwe

    2014-01-01

    phase applying (mostly) well-known technology, albeit in a new setting. DeepWind is a European research project based mostly on new technology. The concepts are described in some detail with emphasis on control and operation. Prospects are discussed including technical challenges and a performance...... metric of energy production per unit steel mass. Floating offshore wind turbines represent a promising technology. The successful operation of HyWind and WindFloat in full scale demonstrates a well advanced technology readiness level, where further development will go into refining the concepts, cost...

  2. Floating Versus Sinking

    Science.gov (United States)

    Vella, Dominic

    2015-01-01

    Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.

  3. Tethered float liquid level sensor

    Energy Technology Data Exchange (ETDEWEB)

    Daily, III, William Dean

    2016-09-06

    An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.

  4. Evaluating convex roof entanglement measures.

    Science.gov (United States)

    Tóth, Géza; Moroder, Tobias; Gühne, Otfried

    2015-04-24

    We show a powerful method to compute entanglement measures based on convex roof constructions. In particular, our method is applicable to measures that, for pure states, can be written as low order polynomials of operator expectation values. We show how to compute the linear entropy of entanglement, the linear entanglement of assistance, and a bound on the dimension of the entanglement for bipartite systems. We discuss how to obtain the convex roof of the three-tangle for three-qubit states. We also show how to calculate the linear entropy of entanglement and the quantum Fisher information based on partial information or device independent information. We demonstrate the usefulness of our method by concrete examples.

  5. Factors Influencing Arthropod Diversity on Green Roofs

    Directory of Open Access Journals (Sweden)

    Bracha Y. Schindler

    2011-01-01

    Full Text Available Green roofs have potential for providing substantial habitat to plants, birds, and arthropod species that are not well supported by other urban habitats. Whereas the plants on a typical green roof are chosen and planted by people, the arthropods that colonize it can serve as an indicator of the ability of this novel habitat to support a diverse community of organisms. The goal of this observational study was to determine which physical characteristics of a roof or characteristics of its vegetation correlate with arthropod diversity on the roof. We intensively sampled the number of insect families on one roof with pitfall traps and also measured the soil arthropod species richness on six green roofs in the Boston, MA area. We found that the number of arthropod species in soil, and arthropod families in pitfall traps, was positively correlated with living vegetation cover. The number of arthropod species was not significantly correlated with plant diversity, green roof size, distance from the ground, or distance to the nearest vegetated habitat from the roof. Our results suggest that vegetation cover may be more important than vegetation diversity for roof arthropod diversity, at least for the first few years after establishment. Additionally, we found that even green roofs that are small and isolated can support a community of arthropods that include important functional groups of the soil food web.

  6. Demonstration of energy savings of cool roofs

    Energy Technology Data Exchange (ETDEWEB)

    Konopacki, S.; Gartland, L.; Akbari, H. [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Rainer, L. [Davis Energy Group, Davis, CA (United States)

    1998-06-01

    Dark roofs raise the summertime air-conditioning demand of buildings. For highly-absorptive roofs, the difference between the surface and ambient air temperatures can be as high as 90 F, while for highly-reflective roofs with similar insulative properties, the difference is only about 20 F. For this reason, cool roofs are effective in reducing cooling energy use. Several experiments on individual residential buildings in California and Florida show that coating roofs white reduces summertime average daily air-conditioning electricity use from 2--63%. This demonstration project was carried out to address some of the practical issues regarding the implementation of reflective roofs in a few commercial buildings. The authors monitored air-conditioning electricity use, roof surface temperature, plenum, indoor, and outdoor air temperatures, and other environmental variables in three buildings in California: two medical office buildings in Gilroy and Davis and a retail store in San Jose. Coating the roofs of these buildings with a reflective coating increased the roof albedo from an average of 0.20--0.60. The roof surface temperature on hot sunny summer afternoons fell from 175 F--120 F after the coating was applied. Summertime average daily air-conditioning electricity use was reduced by 18% (6.3 kWh/1000ft{sup 2}) in the Davis building, 13% (3.6 kWh/1000ft{sup 2}) in the Gilroy building, and 2% (0.4 kWh/1000ft{sup 2}) in the San Jose store. In each building, a kiosk was installed to display information from the project in order to educate and inform the general public about the environmental and energy-saving benefits of cool roofs. They were designed to explain cool-roof coating theory and to display real-time measurements of weather conditions, roof surface temperature, and air-conditioning electricity use. 55 figs., 15 tabs.

  7. Future oriented and more sustainable green roofs

    Energy Technology Data Exchange (ETDEWEB)

    Appl, R.; Ansel, W. [Deutscher Dachgartnerverband, Nuertingen (Germany)

    2004-07-01

    The contribution that green roofs make to sustainable urban Development were discussed with reference to the support that the industry has received in Germany. The German Roof Gardener Association (DDV) was established in the 1990s with an objective to replace the billions of square feet of bare or gravel flat roof surface area in Germany with ecological green roofs. The DDV created guidelines for the systems and components being used in green roof constructions, starting from the raw material to the production and transport of the material, and to the recycling of the material after demolition. Green roofs in Germany are now made mandatory by local authorities. Green roofs offer innovative technological features as well as additional use. Combined with extensive or intensive greening, these roofs reduce the use of building land. They must be built to last the lifetime of the building and given proper care and maintenance. In the twenty-first century, green roof systems will be made of recycled and environmentally sound material. The purpose of the green roof is to provide not only a permanent location for vegetation, but also offer further possibilities of utilization, such as additional thermal insulation, fall protection systems or even constructions for solar power facilities. This paper addressed issues regarding the extended life expectancy of a roof, savings on stormwater tax and thermal values for insulation calculations. Green roofs in Germany currently represent an important element in stormwater management by slowing down, filtering and diminishing rain water runoff. The excess water is guided into cisterns and used for the irrigation of the roof gardens and for flushing toilets. 5 figs.

  8. Demonstration of energy savings of cool roofs

    Energy Technology Data Exchange (ETDEWEB)

    Konopacki, S.; Gartland, L.; Akbari, H. [Lawrence Berkeley National Lab., CA (United States). Environmental Energy Technologies Div.; Rainer, L. [Davis Energy Group, Davis, CA (United States)

    1998-06-01

    Dark roofs raise the summertime air-conditioning demand of buildings. For highly-absorptive roofs, the difference between the surface and ambient air temperatures can be as high as 90 F, while for highly-reflective roofs with similar insulative properties, the difference is only about 20 F. For this reason, cool roofs are effective in reducing cooling energy use. Several experiments on individual residential buildings in California and Florida show that coating roofs white reduces summertime average daily air-conditioning electricity use from 2--63%. This demonstration project was carried out to address some of the practical issues regarding the implementation of reflective roofs in a few commercial buildings. The authors monitored air-conditioning electricity use, roof surface temperature, plenum, indoor, and outdoor air temperatures, and other environmental variables in three buildings in California: two medical office buildings in Gilroy and Davis and a retail store in San Jose. Coating the roofs of these buildings with a reflective coating increased the roof albedo from an average of 0.20--0.60. The roof surface temperature on hot sunny summer afternoons fell from 175 F--120 F after the coating was applied. Summertime average daily air-conditioning electricity use was reduced by 18% (6.3 kWh/1000ft{sup 2}) in the Davis building, 13% (3.6 kWh/1000ft{sup 2}) in the Gilroy building, and 2% (0.4 kWh/1000ft{sup 2}) in the San Jose store. In each building, a kiosk was installed to display information from the project in order to educate and inform the general public about the environmental and energy-saving benefits of cool roofs. They were designed to explain cool-roof coating theory and to display real-time measurements of weather conditions, roof surface temperature, and air-conditioning electricity use. 55 figs., 15 tabs.

  9. Roof Polishing of Optical Fibers

    Science.gov (United States)

    Dholakia, A. R.

    1985-01-01

    Bevealed tip gives optimum coupling efficiency. Abrasive tape used to grind tip of optical fiber. Grinding force depends on stiffness of optical fiber. "Roof" shape on end of optical glass fiber increases efficiency which couples laser light. End surface angle of 65 degrees with perpendicular required for optimum coupling. Since fiber and tape are light in weight and compliant, ridge defect-free, and chipping on fiber edge totally eliminated.

  10. Solar thermal roofs; Zonthermische daken

    Energy Technology Data Exchange (ETDEWEB)

    Van de Waerdt, J. [DWA installatie- en energieadvies, Bodegraven (Netherlands)

    2012-11-15

    The purpose of the brochure is to increase the effective application of solar thermal roofs. The target group includes consultants, installers, architects and contractors. Attention is paid to the design, parameters for comparison, yield simulations and experiences gained in projects [Dutch] Het doel van de brochure is het vergroten van de effectieve toepassing van zonthermische daken. Tot de doelgroep behoren installatieadviseurs, installateurs, architecten en opdrachtgevers in de bouw. Aandacht wordt besteed aan het ontwerp, parameters voor vergelijking, opbrengstsimulaties en ervaringen opgedaan in projecten.

  11. Polyurethane adhesives in flat roofs

    Directory of Open Access Journals (Sweden)

    Bogárová Markéta

    2017-01-01

    Full Text Available It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is to calculate the exact amount of adhesive, which is required to guarantee the resistance against wind suction. In this problematic we can not find help neither in technical data sheets provided by the manufactures. Some of these data sheets contain at least information about amount of adhesive depending on location in roof plane and building height, but they do not specify the strength of such connection. It was therefore resorted to select several representatives polyurethane adhesives and their subsequent testing on specimens simulating the flat roof segment. The paper described the test methodology and results for two types of polyurethane adhesives.

  12. Extensive Green Roof Ecological Benefits in Latvia

    OpenAIRE

    Rušenieks, Rihards; Kamenders, Agris

    2013-01-01

    Extensive green roof ecological benefits are studiedin this paper. The research contains a brief explanation aboutgreen roof technology and green roof ecological benefits. Greenroof capability to retain rainwater runoff by accumulating it instorage layers and conducting it back into the atmospherethrough evapotranspiration is studied and modeled. Modeling isdone in Stormwater Management Model 5.0 software. The modelis based on an existing warehouse-type building located in Rigaand hourly Riga...

  13. Realistic roofs over a rectilinear polygon

    KAUST Repository

    Ahn, Heekap

    2013-11-01

    Given a simple rectilinear polygon P in the xy-plane, a roof over P is a terrain over P whose faces are supported by planes through edges of P that make a dihedral angle π/4 with the xy-plane. According to this definition, some roofs may have faces isolated from the boundary of P or even local minima, which are undesirable for several practical reasons. In this paper, we introduce realistic roofs by imposing a few additional constraints. We investigate the geometric and combinatorial properties of realistic roofs and show that the straight skeleton induces a realistic roof with maximum height and volume. We also show that the maximum possible number of distinct realistic roofs over P is ((n-4)(n-4)/4 /2⌋) when P has n vertices. We present an algorithm that enumerates a combinatorial representation of each such roof in O(1) time per roof without repetition, after O(n4) preprocessing time. We also present an O(n5)-time algorithm for computing a realistic roof with minimum height or volume. © 2013 Elsevier B.V.

  14. Green roofs provide habitat for urban bats

    Directory of Open Access Journals (Sweden)

    K.L. Parkins

    2015-07-01

    Full Text Available Understanding bat use of human-altered habitat is critical for developing effective conservation plans for this ecologically important taxon. Green roofs, building rooftops covered in growing medium and vegetation, are increasingly important conservation tools that make use of underutilized space to provide breeding and foraging grounds for urban wildlife. Green roofs are especially important in highly urbanized areas such as New York City (NYC, which has more rooftops (34% than green space (13%. To date, no studies have examined the extent to which North American bats utilize urban green roofs. To investigate the role of green roofs in supporting urban bats, we monitored bat activity using ultrasonic recorders on four green and four conventional roofs located in highly developed areas of NYC, which were paired to control for location, height, and local variability in surrounding habitat and species diversity. We then identified bat vocalizations on these recordings to the species level. We documented the presence of five of nine possible bat species over both roof types: Lasiurus borealis, L. cinereus, L. noctivagans, P. subflavus,andE. fuscus. Of the bat calls that could be identified to the species level, 66% were from L. borealis. Overall levels of bat activity were higher over green roofs than over conventional roofs. This study provides evidence that, in addition to well documented ecosystem benefits, urban green roofs contribute to urban habitat availability for several North American bat species.

  15. Orbital dystopia due to orbital roof defect.

    Science.gov (United States)

    Rha, Eun Young; Joo, Hong Sil; Byeon, Jun Hee

    2013-01-01

    We performed a retrospective review of patients who presented with delayed dystopia as a consequence of an orbital roof defect due to fractures and nontraumatic causes to search for a correlation between orbital roof defect size and surgical indications for the treatment thereof. Retrospective analyses were performed in 7 patients, all of whom presented with delayed dystopia due to orbital roof defects, between January 2001 and June 2011. The causes of orbital roof defects were displaced orbital roof fractures (5 cases), tumor (1 case), and congenital sphenoid dysplasia (1 case). All 7 patients had initially been treated conservatively and later presented with significant dystopia. The sizes of the defects were calculated on computed tomographic scans. Among the 7 patients, aspiration of cerebrospinal fluid, which caused ocular symptoms, in 1 patient with minimal displaced orbital roof and reconstruction with calvarial bone, titanium micromesh, or Medpor in 6 other patients were performed. The minimal size of the orbital roof in patients who underwent orbital roof reconstruction was 1.2 cm (defect height) x 1.0 cm (defect length), 0.94 cm(2). For all patients with orbital dystopia, displacement of the globe was corrected without any complications, regardless of whether the patient was evaluated grossly or by radiology. In this retrospective study, continuous monitoring of clinical signs and active surgical management should be considered for cases in which an orbital roof defect is detected, even if no definite symptoms are noted, to prevent delayed sequelae.

  16. Unique Roll-Off Roof for Housing 1.3 m Telescope at Devasthal, Nainital

    Science.gov (United States)

    Bangia, Tarun

    2017-06-01

    Aryabhatta Research Institute of Observational Sciences (ARIES) had set up a 1.3 m telescope at Devasthal, Nainital, India in the year 2010. Country's largest roll-off roof was indigenously designed, fabricated and installed on top of a building (17 × 8 m) for housing 1.3 m telescope. Telescope was supplied by M/s DFM Engineering Inc., USA to ARIES and was installed in the building with unique roll-off roof to protect it from external environment. Roll-off roof was designed and fabricated considering various parameters and available manpower and resources at ARIES. This paper presents mechanical development work, simple but distinct design approach and innovative selection of materials to economically manufacture roll-off roof of large size (8 × 8 × 4 m) at hilly remote site of Devasthal situated in Central Himalayan region. All operations in the roof viz. opening of shutters and rolling of roof were motorized to facilitate observers during night observations.

  17. Floating Ocean Platform

    Science.gov (United States)

    2003-08-15

    REVIEW, 83-89 Int. Hydrogr. Rev., 1986 ARANHA , JAP PESCE, CP, EFFECT OF THE 2ND-ORDER POTENTIAL IN THE SLOW-DRIFT OSCILLATION OF A FLOATING STRUCTURE...Technology Conference, Annual Proceedings, v 3, Construction & Installation/Field Drilling and Development Systems, 1997, OTC 8696, p 133-142 Aranha , J...Andre J.P. (Petrobras/Depro); Nishimoto, Kazuo; Aranha , J.A.P.; Morooka, Celso K., Minimization of vertical wave exciting force and heave motion of a

  18. Serial floating point formatter

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, R. D.; Penner, W. A.

    1985-11-12

    A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

  19. Floating point coprocessor upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T.

    1987-04-01

    A method was developed to increase the throughput of the Hewlett Packard, 98635A floating point processor equipped, model 236C computer. The increase was carried out in three phases each with a clock and or chip change during the modification. Two programs were written to test the results and evaluate the increases in performance made to the computer. The first one shows reduction in processing times of 34.3%, while the other recorded 34.6%.

  20. Impact on floating membranes

    OpenAIRE

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends...

  1. 上海浦东南汇地区流动人口“三病”检疫10年监测分析%Analysis of monitoring of “quarantine of three diseases” among external floating population for a period of 10 years in Nanhui District, Shanghai

    Institute of Scientific and Technical Information of China (English)

    宋海红

    2011-01-01

    目的 了解和分析上海南汇地区外来流动人员血吸虫病、疟疾、丝虫病检疫的现况,为今后的外来人员管理和监测工作提供对策.方法 采用免疫酶染技术及三联抗原片,对外来流动人员进行血吸虫免疫测定、疟疾血片免疫测定及疟原虫血检和丝虫免疫测定.结果 接受检疫的54 386名外来流动人员中,抗体总阳性率为0.69%,其中,血吸虫抗体阳性率为0.24%,疟疾阳性率为0.36%,丝虫阳性率为0.09%.结论 由于大量外来流动人员的涌入,导致血吸虫病、疟疾、丝虫病流行的危险因素依然存在,因而要加强对外来人员的监测,规范流动人口管理的条例和管理方法,以控制传染源.%Objectives To understand infectious status of schistosomiasis,malaria and filariasis in external floating population in Nanhui District of Shanghai. Methods The infectious status of schistosomiasis,malaria and fialrasis in external floating population was detected with immune enzyme staining,and immunoassay. Results Totally 54 386 people moved in from outside of Nanhui District were detected and the antibody positive rate was 0.69% ,being 0.24% for schistosoma,0.36% for plasmodium and 0.09% for filaria. Conclusion Due to influx of foreign travelers,there is the risk of prevalence of schistosomiasis,filariasis and malaria,thus the quarantine and monitoring of the three infective diseases should be strengthened.

  2. Collapsing floating-point operations

    OpenAIRE

    Defour, David

    2004-01-01

    This paper addresses the issue of collapsing dependent floating-point operations. The presentation focuses on studying the dataflow graph of benchmark involving a large number of floating-point instructions. In particular, it focuses on the relevance of new floating-point operators performing two dependent operations which are similar to "fused multiply and add". Finally, this paper examines the implementation cost and critical path reduction from this strategy.

  3. FLOPAK: FLOATING POINT PROGRAMING PACKAGE,

    Science.gov (United States)

    FLOPAK is a Packard-Bell 250 Computer semi-automatic, floating - point programing system which may be operated simultaneously in either of two modes...250 floating - point system available which may be used in real-time control. The system was originally designed to solve a real-time communication problem....The first is a non-time optimized mode which may be used by inex perienced coders; the second mode is a high-speed, fully time-optimized floating

  4. Wind loads on solar energy roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bentum, C.A. van

    2007-01-01

    This paper presents an overview of the wind loads on roofs, equipped with solar energy products, so called Active Roofs. Values given in this paper have been based on wind tunnel and full scale measurements, carried out at TNO, and on an interpretation of existing rules and guidelines. The results a

  5. Integrated roof wind energy system

    Directory of Open Access Journals (Sweden)

    Moonen S.P.G.

    2012-10-01

    Full Text Available Wind is an attractive renewable source of energy. Recent innovations in research and design have reduced to a few alternatives with limited impact on residential construction. Cost effective solutions have been found at larger scale, but storage and delivery of energy to the actual location it is used, remain a critical issue. The Integrated Roof Wind Energy System is designed to overcome the current issues of urban and larger scale renewable energy system. The system is built up by an axial array of skewed shaped funnels that make use of the Venturi Effect to accelerate the wind flow. This inventive use of shape and geometry leads to a converging air capturing inlet to create high wind mass flow and velocity toward a vertical-axis wind turbine in the top of the roof for generation of a relatively high amount of energy. The methods used in this overview of studies include an array of tools from analytical modelling, PIV wind tunnel testing, and CFD simulation studies. The results define the main design parameters for an efficient system, and show the potential for the generation of high amounts of renewable energy with a novel and effective system suited for the built environment.

  6. Integrated roof wind energy system

    Science.gov (United States)

    Suma, A. B.; Ferraro, R. M.; Dano, B.; Moonen, S. P. G.

    2012-10-01

    Wind is an attractive renewable source of energy. Recent innovations in research and design have reduced to a few alternatives with limited impact on residential construction. Cost effective solutions have been found at larger scale, but storage and delivery of energy to the actual location it is used, remain a critical issue. The Integrated Roof Wind Energy System is designed to overcome the current issues of urban and larger scale renewable energy system. The system is built up by an axial array of skewed shaped funnels that make use of the Venturi Effect to accelerate the wind flow. This inventive use of shape and geometry leads to a converging air capturing inlet to create high wind mass flow and velocity toward a vertical-axis wind turbine in the top of the roof for generation of a relatively high amount of energy. The methods used in this overview of studies include an array of tools from analytical modelling, PIV wind tunnel testing, and CFD simulation studies. The results define the main design parameters for an efficient system, and show the potential for the generation of high amounts of renewable energy with a novel and effective system suited for the built environment.

  7. Thermal insulation performance of green roof systems

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Serdar; Morgan, Susan; Retzlaff, William; Once, Orcun [southern Illinois University (United States)], e-mail: scelik@siue.edu, e-mail: smorgan@siue.edu, e-mail: wretzla@siue.edu, e-mail: oonce@siue.edu

    2011-07-01

    With the increasing costs of energy, good building insulation has become increasingly important. Among existing insulation techniques is the green roof system, which consists of covering the roof of a building envelop with plants. The aim of this paper is to assess the impact of vegetation type and growth media on the thermal performance of green roof systems. Twelve different green roof samples were made with 4 different growth media and 3 sedum types. Temperature at the sample base was recorded every 15 minutes for 3 years; the insulation behavior was then analysed. Results showed that the insulation characteristics were achieved with a combination of haydite and sedum sexangulare. This study demonstrated that the choice of growth media and vegetation is important to the green roof system's performance; further research is required to better understand the interactions between growth media and plant roots.

  8. Experimental polyurethane foam roof systems, part 2

    Science.gov (United States)

    Alumbaugh, R. L.; Keeton, J. R.; Humm, E. F.

    1983-01-01

    An experimental roofing installation is described in which polyurethane foam (PUF) was spray-applied directly to metal Butlerib-type metal decks, the roof divided into five approximately equal areas, and the PUF protected with five different elastomeric coating systems. Three of the coating systems were damaged by hailstones about a year after installation; these systems were recoated within 3 years of the initial installation. The current coatings include two of the original coating systems - a plural component silicone and a single component silicone - and those applied over the three systems damaged by hail - a single component silicone, an aluminum filled, hydrocarbon-extended catalyzed urethane, and a catalyzed urethane. The performance of these five PUF systems over a 7-year period is reported. The temperature distributions throughout the roof systems are described. The decay in the thermal conductivity of the PUF roof over a 5-year period is presented, and the energy savings realized by foaming the roof are presented.

  9. Study on Floating Properties and Stability of Air Floated Structures

    Institute of Scientific and Technical Information of China (English)

    别社安; 及春宁; 任增金; 李增志

    2002-01-01

    In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoreticaland experimental methods. The equations for calculation of the buoyancy of the air floated buoy are derived according tothe Boyler law and the equilibrium equations of the air floated structure are established. Through simplification of the airfloated structure as a single freedom rigid body and spring system, the natural period of heaving and some kinetic proper-ties are discussed. In the stability analysis, the formulas for calculation of the meta centric height are presented. The the-oretical results are in good agreement with the data observed from the model test and prototype test. The air buoyancy de-crease coefficient presented in this paper has a large influence on the floating state, stability and dynamic properties of theair floated structure. The stability of the air floated structure can also be judged by the parameter of meta centric height,and calculations show that the air floated structure is less stable than the conventional float.

  10. Floating JMaRT

    CERN Document Server

    Bossard, Guillaume

    2014-01-01

    We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.

  11. Analysis of Responses of Floating Dual Pontoon Structure

    Institute of Scientific and Technical Information of China (English)

    WENG Wen-Kai; CHOU Chung-Ren

    2007-01-01

    A numerical model is developed by use of the boundary integral equation method to investigate the responses of a two-dimensional floating structure.The structure under consideration consisting of two pontoons,is connected by a rigid framework,and linked to the sea floor by a mooring system.The theoretical conception is based on potential theory with linear external forces,and applied to an arbitrarily shaped body and water depth.The discussion includes the influence of draft and space between pontoons on the responses of the floating structure.Finally,the validity of the method is adequately verified by experimental results.

  12. Roof Rockmass Characterization in an Illinois Underground Coal Mine

    Science.gov (United States)

    Osouli, Abdolreza; Shafii, Iman

    2016-08-01

    Among all United States underground coal fields, those in Illinois have the highest rate of roof fall events due to their weak and severely moisture sensitive roof rock units. Rockmass characterization is the key initial step in designing safe and economical roof control measures in underground coal mines. In this study, a performance-based roof rockmass characterization is investigated. The geologic conditions as well as underground mine geographic specifications, roof fall analysis, mining method, utilized supplemental roof control measures, and geotechnical properties of roof rock units were considered to link the roof performance to rockmass characterization. The coal mine roof rating (CMRR) rockmass characterization method was used to evaluate the roof conditions and roof support design for an underground coal mine located in the Illinois Coal Basin. The results of several mine visit mappings, laboratory test results, and geotechnical issues and concerns are presented and discussed. The roof support designs are analyzed based on the rockmass characterization and are compared with the observed performance. This study shows that (1) CMRR index is a reasonable method for characterizing roof rockmass; (2) moisture sensitivity and bedding strengths in the horizontal direction are essential parameters for roof support design in mines with weak roof conditions; and (3) the applicability of the analysis of roof bolt system for roof support design of the studied mine is questionable.

  13. Green roof stormwater retention: effects of roof surface, slope, and media depth.

    Science.gov (United States)

    VanWoert, Nicholaus D; Rowe, D Bradley; Andresen, Jeffrey A; Rugh, Clayton L; Fernandez, R Thomas; Xiao, Lan

    2005-01-01

    Urban areas generate considerably more stormwater runoff than natural areas of the same size due to a greater percentage of impervious surfaces that impede water infiltration. Roof surfaces account for a large portion of this impervious cover. Establishing vegetation on rooftops, known as green roofs, is one method of recovering lost green space that can aid in mitigating stormwater runoff. Two studies were performed using several roof platforms to quantify the effects of various treatments on stormwater retention. The first study used three different roof surface treatments to quantify differences in stormwater retention of a standard commercial roof with gravel ballast, an extensive green roof system without vegetation, and a typical extensive green roof with vegetation. Overall, mean percent rainfall retention ranged from 48.7% (gravel) to 82.8% (vegetated). The second study tested the influence of roof slope (2 and 6.5%) and green roof media depth (2.5, 4.0, and 6.0 cm) on stormwater retention. For all combined rain events, platforms at 2% slope with a 4-cm media depth had the greatest mean retention, 87%, although the difference from the other treatments was minimal. The combination of reduced slope and deeper media clearly reduced the total quantity of runoff. For both studies, vegetated green roof systems not only reduced the amount of stormwater runoff, they also extended its duration over a period of time beyond the actual rain event.

  14. Floating shoulder” injuries

    OpenAIRE

    Heng, Kenneth

    2016-01-01

    Floating shoulder” is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.

  15. Treatment of Floating Knee Injury in Children

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The necessity and superiority of the surgical operation on children with floating knee injury and the fracture union and complications were investigated. Twenty-eight children with floating knee injury were subjected to open reduction and internal fixation or external fixator. The patients were followed up for 18 months to 7 years. The curative effectiveness was scored by Karlstrom criteria. The results showed that no nonunion or deformity was found. The affected limb was 1.2 cm to 1.5 cm longer in 2 cases, 0.8 to 1.2 cm shorter in 3 cases than the contralateral. No severe dysfunction of knee joint occurred. The excellent-good rate was 92.8 % and the curative rate 71.4 % respectively. So for children whose age is older than 5 years, it's a good way to treat the fractures of femur and tibia with open reduction and internal fixation or external fixator. The method can be advantageous for the nursing care, early function recovery, shortening of the hospital stay and avoidance of severe complications.

  16. Solar roof Spansko-Croatia

    Energy Technology Data Exchange (ETDEWEB)

    Majdandzic, L. [Croatian Professional Society for Solar Energy, Zagreb (Croatia); Peric, M. [Brodarski Institute, Zagreb (Croatia); Matic, Z. [Hrvoje Pozar Energy Institute, Zagreb (Croatia)

    2004-07-01

    This paper presents a project named ''Solar roof Spansko-Zagreb'' with data for half a year of operation. This is the first grid-connected project in the Republic of Croatia. The project comprises of solar collectors providing thermal energy, and of PV modules providing electricity. This building does not emit carbon dioxide into the environment, a major contributor of global warming. The concept shows that passive and active use of solar energy can meet power needs of a building, without disrupting the comfort of habitation. The building reduces consumption of fossil fuels thus reducing the emission of harmful substances into the environment. This project represents an initiative for increased use of solar energy, especially on islands in coastal region and hinterland of Croatia. (orig.)

  17. Decision Guide for Roof Slope Selection

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1988-01-01

    This decision guide has been written for personnel who are responsible for the design, construction, and replacement of Air Force roofs. It provides the necessary information and analytical tools for making prudent and cost-effective decisions regarding the amount of slope to provide in various roofing situations. Because the expertise and experience of the decision makers will vary, the guide contains both basic slope-related concepts as well as more sophisticated technical data. This breadth of information enables the less experienced user to develop an understanding of roof slope issues before applying the more sophisticated analytical tools, while the experienced user can proceed directly to the technical sections. Although much of this guide is devoted to the analysis of costs, it is not a cost-estimating document. It does, however, provide the reader with the relative costs of a variety of roof slope options; and it shows how to determine the relative cost-effectiveness of different options. The selection of the proper roof slope coupled with good roof design, a quality installation, periodic inspection, and appropriate maintenance and repair will achieve the Air Force's objective of obtaining the best possible roofing value for its buildings.

  18. Maximal loads acting on legs of powered roof support unit in longwalls with bumping hazards

    Institute of Scientific and Technical Information of China (English)

    StanislawSzweda

    2001-01-01

    In the article the results of measurements of the resultant force in the legs of a powered roof support unit, caused by a dynamic interaction bf the rock mass, are discussed. The measurements have been taken in the Iongwalls mined with a roof fall, characterized by the highest degree of bumping hazard. It has been stated that the maximal force in the legs Fro, recorded during a dynamic interaction of the rock mass, is proportional to the initial static force in the legs Fst.p Therefore a need for a careful selection of the initial load of the powered roof support, according to the local mining and geological conditions, results from such a statement. Setting the legs with the supporting load exceeding the indispensable value for keeping the direct roof solids in balance, deteriorating the operational parameters of a Iongwall system also has a disadvantageous influence on the value of the force in the legs and the rate of its increase, caused by a dynamic interaction of the rock mass. A correct selection of the initial load causes a decrease in the intensity of a dynamic interaction of the rock mass on powered roof supports, which also has an advanta igeous influence on their life, Simultaneously with the measurements of the resultant force in the legs, the vertical acceleration of the canopy was also recorded. It has enabled to prove that the external dynamic forces may act on the unit both from the roof as well as from the floor. The changes of the force in the legs caused by dynamic phenomena intrinsically created in the roof and changes of the force in the legs caused by blasting explosives in the roof of the working, have been analyzed separately. It has been stated that an increase in the loads of legs, caused by intrinsic phenomena is significantly higher than a force increase in the legs caused by blasting. It means that powered roof supports, to be operated in the workings, where the bumping hazard occurs, will also transmit the loads acting on a unit

  19. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  20. Horizontal roof gap of backfill hydraulic support

    Institute of Scientific and Technical Information of China (English)

    张强; 张吉雄; 邰阳; 方坤; 殷伟

    2015-01-01

    For the backfill hydraulic support as the key equipment for achieving integration of backfilling and coal mining simultaneously in the practical process, its characteristics will directly influence the backfill body’s compression ratio. Horizontal roof gap, as a key parameter of backfilling characteristics, may impact the backfilling effect from the aspects of control of roof subsidence in advance, support stress, backfilling process and the support design. Firstly, the reason why horizontal roof gap exists was analyzed and its definition, causes and connotation were introduced, then adopting the Pro/E 3D simulation software, three typical 3D entity models of backfill hydraulic supports were built, based on the influence of horizontal roof gap on backfilling effect, and influence rules of four factors, i.e. support height, suspension height, suspension angle and tamping angle, were emphatically analyzed on horizontal roof gap. The results indicate that, the four factors all have significant impacts on horizontal roof gap, but show differences in influence trend and degree, showing negative linear correlation, positive linear correlation, positive semi-parabolic correlation and negative semi-parabolic correlation, respectively. Four legs type is the most adaptive to the four factors, while six legs (II) type has the poorest adaptability, and the horizontal roof gap is small under large support height, small suspension height, small suspension angle and large tamping angle situation. By means of optimizing structure components and their positional relation and suspension height of backfill scrape conveyor in the process of support design and through controlling working face deployment, roof subsidence in advance, mining height and backfilling during engineering application, the horizontal roof gap is optimized. The research results can be served as theoretical basis for support design and guidance for backfill support to have better performance in backfilling.

  1. STUDY ON HARD ROOF ROCKBURST IN COAL MINE

    Institute of Scientific and Technical Information of China (English)

    潘一山; 陈德军; 章梦涛

    1997-01-01

    Based on practical observation in Mentougou Mine, a general law of roof rockburst is put forward. The destabilization theory of roof rockburst has been established. The general laws of microquake premonition and earth sound in roof rockburst is advanced. The relationship between roof rockburst and rockburst of coal body is studied.

  2. Analysis on thermal measuring of green roof

    Institute of Scientific and Technical Information of China (English)

    唐鸣放; 蒋琳

    2009-01-01

    Comparison of thermal performance between a green roof room and a bare roof room was presented during the cooling period in Shanghai. The results show that the electricity can be saved about 0.08 kW·h/(d·m2),and the heat flux can be reduced by about 70%; the inner surface temperature variation is about 1.0 ℃ comparing with the indoor temperature when using the green roof,and the extra equivalent heat resistance is 1.0 m2·K/W.

  3. Optimum Insulation Thickness for Walls and Roofs for Reducing Peak Cooling Loads in Residential Buildings in Lahore

    Directory of Open Access Journals (Sweden)

    SIBGHA SIDDIQUE SIDDIQUE

    2016-10-01

    Full Text Available Thermal insulation is the most effective energy saving measure for cooling in buildings. Therefore, the main subject of many engineering investigations is the selection and determination of the optimum insulation thickness. In the present study, the optimum insulation thickness on external walls and roofs is determined based on the peak cooling loads for an existing residential building in Lahore, Pakistan. Autodesk® Revit 2013 is used for the analysis of the building and determination of the peak cooling loads. The analysis shows that the optimum insulation thickness to reduce peak cooling loads up to 40.1% is 1 inch for external walls and roof respectively.

  4. Metal and nutrient dynamics on an aged intensive green roof.

    Science.gov (United States)

    Speak, A F; Rothwell, J J; Lindley, S J; Smith, C L

    2014-01-01

    Runoff and rainfall quality was compared between an aged intensive green roof and an adjacent conventional roof surface. Nutrient concentrations in the runoff were generally below Environmental Quality Standard (EQS) values and the green roof exhibited NO3(-) retention. Cu, Pb and Zn concentrations were in excess of EQS values for the protection of surface water. Green roof runoff was also significantly higher in Fe and Pb than on the bare roof and in rainfall. Input-output fluxes revealed the green roof to be a potential source of Pb. High concentrations of Pb within the green roof soil and bare roof dusts provide a potential source of Pb in runoff. The origin of the Pb is likely from historic urban atmospheric deposition. Aged green roofs may therefore act as a source of legacy metal pollution. This needs to be considered when constructing green roofs with the aim of improving pollution remediation.

  5. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  6. Impact on floating membranes

    CERN Document Server

    Vandenberghe, Nicolas

    2016-01-01

    When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends on the local stretching rate. We study the dynamics of this fluid-body system and we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. We emphasize the role of the stretching in the membrane in the wave dynamics but also in the development of a buckling instability that give rise to radial wrinkles.

  7. Hydrologic Restoration in the Urban Environment Using Green Roofs

    OpenAIRE

    Anna Palla; Ilaria Gnecco; Luca G. Lanza

    2010-01-01

    Loss of natural soil and vegetation within the urban environment can significantly affect the hydrologic cycle by increasing storm water runoff rates and volumes. In order to mitigate these modifications in urban areas engineered systems are developed, such as green roofs, to mimic and replace functions (evapo-transpiration, infiltration, percolation) which have been altered due to the impact of human development. Green roofs, also known as vegetated roof covers, eco-roofs or nature roofs, ar...

  8. Building Integrated Photovoltaic (BIPV) Roofs for Sustainability and Energy Efficiency

    Science.gov (United States)

    2014-04-01

    conventional dark roofs, but the degradation in the first few years was significant. This was primarily due to soiling and not actual roof membrane... degradation . Since roof cleaning is not a typical DoD operations or maintenance activity, roof reflectivity was measured with the soiling during the...Roof albedo was originally planned to be measured for only Site III (MCAS Yuma), but since there were different soiling /aging/ degradation conditions

  9. Improving the durability of flat roof constructions

    DEFF Research Database (Denmark)

    Rudbeck, Claus Christian; Svendsen, Sv Aa Højgaard

    1999-01-01

    Flat roof constructions are mainly used on commercial, institutional and industrial buildings, where insulation is placed on top of the load-bearing deck and then covered with a roof membrane. Through time, there is a risk that the membrane will allow water passage as holes might form due...... as there is no easy method of drying it. To be able to dry the insulation, and thereby regain the functional requirements of the roofing system, two new solutions for insulating flat roofs with existing materials are proposed for high density mineral wool and expanded polystyrene. Monitoring equipment are part...... to weathering effects or physical loads. Water will then enter the insulation, and as a vapor retarder is normally found below the insulation thus trapping the water in the insulation, the leak can remain undetected for a long period. When the leak is finally discovered, the insulation has to be discharged...

  10. Carbon sequestration potential of extensive green roofs.

    Science.gov (United States)

    Getter, Kristin L; Rowe, D Bradley; Robertson, G Philip; Cregg, Bert M; Andresen, Jeffrey A

    2009-10-01

    Two studies were conducted with the objective of quantifying the carbon storage potential of extensive green roofs. The first was performed on eight roofs in Michigan and four roofs in Maryland, ranging from 1 to 6 years in age. All 12 green roofs were composed primarily of Sedum species, and substrate depths ranged from 2.5 to 12.7 cm. Aboveground plant material was harvested in the fall of 2006. On average, these roofs stored 162 g C x m(-2) in aboveground biomass. The second study was conducted on a roof in East Lansing, MI. Twenty plots were established on 21 April 2007 with a substrate depth of 6.0 cm. In addition to a substrate only control, the other plots were sown with a single species of Sedum (S. acre, S. album, S. kamtshaticum, or S. spurium). Species and substrate depth represent typical extensive green roofs in the United States. Plant material and substrate were harvested seven times across two growing seasons. Results at the end of the second year showed that aboveground plant material storage varied by species, ranging from 64 g C x m(-2) (S. acre) to 239 g C x m(-2) (S. album), with an average of 168 g C x m(-2). Belowground biomass ranged from 37 g C x m(-2) (S. acre) to 185 g C x m(-2) (S. kamtschaticum) and averaged 107 g C x m(-2). Substrate carbon content averaged 913 g C x m(-2), with no species effect, which represents a sequestration rate of 100 g C x m(-2) over the 2 years of this study. The entire extensive green roof system sequestered 375 g C x m(-2) in above- and belowground biomass and substrate organic matter.

  11. Green Roofs and Green Building Rating Systems

    OpenAIRE

    Liaw; Chao-Hsien

    2015-01-01

    The environmental benefits for green building from the Leadership in Energy and Environment Design (LEED) and Ecology, Energy, Waste, and Health (EEWH) rating systems have been extensively investigated; however, the effect of green roofs on the credit-earning mechanisms is relatively unexplored. This study is concerned with the environmental benefits of green roofs with respect to sustainability, stormwater control, energy savings, and water resources. We focused on the relationsh...

  12. Six aspects to inspirational green roof design

    Energy Technology Data Exchange (ETDEWEB)

    Kiers, H. [SWA Group, Sausalito, CA (United States)

    2004-07-01

    Green roofs have been categorized as a technology that is not initially faster, better or cheaper, and may even under perform established products. However, green roofs have features and values that early adopters are ready to experiment with in small markets, thereby creating awareness of the technology. Termed as disruptive technologies, green roofs can become competitive within the mainstream market against established products. The challenge in green roof construction is to find the correct balance between idealistic principles and leading edge design. This paper presented case studies to examine the following 6 aspects of design fundamentals to the creation of inspirational green roofs: the use of colour; experimentation with materials and technology; incorporation of texture, form, and pattern; definition of space; engagement of vistas; and, principles of bio-regionalism. It was concluded that good design is not enough to lead to widespread green roof implementation. It was emphasized that change will occur primarily because of the benefits acquired through implementation. 11 refs., 7 figs.

  13. NULL Convention Floating Point Multiplier

    Directory of Open Access Journals (Sweden)

    Anitha Juliette Albert

    2015-01-01

    Full Text Available Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.

  14. NULL convention floating point multiplier.

    Science.gov (United States)

    Albert, Anitha Juliette; Ramachandran, Seshasayanan

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.

  15. Electrically floating, near vertical incidence, skywave antenna

    Science.gov (United States)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  16. NULL Convention Floating Point Multiplier

    OpenAIRE

    Anitha Juliette Albert; Seshasayanan Ramachandran

    2015-01-01

    Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to p...

  17. Large floating structures technological advances

    CERN Document Server

    Wang, BT

    2015-01-01

    This book surveys key projects that have seen the construction of large floating structures or have attained detailed conceptual designs. This compilation of key floating structures in a single volume captures the innovative features that mark the technological advances made in this field of engineering, and will provide a useful reference for ideas, analysis, design, and construction of these unique and emerging urban projects to offshore and marine engineers, urban planners, architects and students.

  18. Cost Comparative Study On Steel Frame Folded Plate Roofing System Vs Conventional Truss Roofing System

    Directory of Open Access Journals (Sweden)

    T. Subramani

    2014-12-01

    Full Text Available Due to ever-increasing of construction materials, it becomes the foremost duty of a civil engineer to design economical and durable structures. In this project an attempt has been made to compare the cost of two types of roofing systems viz. conventional truss roofing system and steel frame folded plate roofing system. The steel frame folded plate roofing system, though found to be economical, is not widely practiced in India due to lack of knowledge regarding its analysis and design. On contrary to it, the conventional truss roofing system still remains as the widely adopted method of roofing for different types of buildings due to the available literature on its analysis, design and construction. The analysis and design of conventional truss roofing system and folded plate roofing system have been carried out for various spans. The analysis is carried out in STAAD.Pro 2004, which is based on stiffness method. Load calculations and design done manually, based on IS:875-1987, IS:800- 1984 & SP:38(1987

  19. 40 CFR 63.653 - Monitoring, recordkeeping, and implementation plan for emissions averaging.

    Science.gov (United States)

    2010-07-01

    ... internal floating roof, external roof, or a closed vent system with a control device, as appropriate to the... control technique other than an internal or external floating roof or a closed vent system with a control... § 63.120 of subpart G; and (ii) For closed vent systems with control devices, conduct an initial...

  20. Green roof valuation: a probabilistic economic analysis of environmental benefits.

    Science.gov (United States)

    Clark, Corrie; Adriaens, Peter; Talbot, F Brian

    2008-03-15

    Green (vegetated) roofs have gained global acceptance as a technologythat has the potential to help mitigate the multifaceted, complex environmental problems of urban centers. While policies that encourage green roofs exist atthe local and regional level, installation costs remain at a premium and deter investment in this technology. The objective of this paper is to quantitatively integrate the range of stormwater, energy, and air pollution benefits of green roofs into an economic model that captures the building-specific scale. Currently, green roofs are primarily valued on increased roof longevity, reduced stormwater runoff, and decreased building energy consumption. Proper valuation of these benefits can reduce the present value of a green roof if investors look beyond the upfront capital costs. Net present value (NPV) analysis comparing a conventional roof system to an extensive green roof system demonstrates that at the end of the green roof lifetime the NPV for the green roof is between 20.3 and 25.2% less than the NPV for the conventional roof over 40 years. The additional upfront investment is recovered at the time when a conventional roof would be replaced. Increasing evidence suggests that green roofs may play a significant role in urban air quality improvement For example, uptake of N0x is estimated to range from $1683 to $6383 per metric ton of NOx reduction. These benefits were included in this study, and results translate to an annual benefit of $895-3392 for a 2000 square meter vegetated roof. Improved air quality leads to a mean NPV for the green roof that is 24.5-40.2% less than the mean conventional roof NPV. Through innovative policies, the inclusion of air pollution mitigation and the reduction of municipal stormwater infrastructure costs in economic valuation of environmental benefits of green roofs can reduce the cost gap that currently hinders U.S. investment in green roof technology.

  1. Floating wind turbine system

    Science.gov (United States)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  2. Impact on floating membranes

    Science.gov (United States)

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-05-01

    When impacted by a rigid body, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. First, a longitudinal wave front, associated with in-plane deformation of the membrane and traveling at constant speed, separates an outward stress-free domain from a stretched domain. Then, in the stretched domain a dispersive transverse wave travels at a speed that depends on the local stretching rate. The dynamics is found to be self-similar in time. Using this property, we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. During wave propagation, we observe the development of a buckling instability that gives rise to radial wrinkles. We address the dynamics of this fluid-body system, including the rapid deceleration of an impactor of finite mass, an issue that may have applications in the domain of absorption of impact energy.

  3. Maximal loads acting on legs of powered roof support unit in longwalls with bumping hazards

    Institute of Scientific and Technical Information of China (English)

    Stanislaw Szweda

    2001-01-01

    acting on a unit du ring blasting. The majority of recorded force changes in the legs has been caused by a dyna mic interaction of the roof. They are characterized by a load increase coefficie nt Kd, satisfying the inequality 1.06external load acted on the bases, w as recorded. Individual, recorded results of measurements indicate that changes of the force in the legs, caused by external loads of this type, run more inten sively due to roof loads (1.08roof layer of the seam is under mining. A determination of more precise relations among the changes of forces in the legs, caused by a dynamic interacti on of the floor and the bases and the mining and geological conditions requires a performance of additional underground tests.

  4. Retention capacity of extensive green roofs

    Directory of Open Access Journals (Sweden)

    Sobczyk Małgorzata

    2016-09-01

    Full Text Available Climate change causes a more frequent occurrence of extreme events. The result of these phenomena is the occurrence of floods and flooding, and periods of drought. Particularly unfavorable is intensive rainfall over the urban catchments. To prevent the negative consequences of these phenomena, unconventional solutions should be used. The use of green roofs in urban areas will serve the sustainable development of cities and the impact on local ecological changes. The study was performed at two green roof platforms 1.2×1.2×0.1 m each. An analysis was performed at different intensities given for precipitation. 20 min for the rain to stop was observed from 68 to 100% precipitation. The study was divided into two parts. The first part of the study has been performed in the dry period. In contrast, another round of tests was repeated in other conditions after rainfall. The amount of water at two experimental green roofs platforms before the test was 11.0 dm3. The research relates to the impact of green roofs on local hydrological changes. Development of technologies for green roofs had a positive impact on mitigating the effects of climate change associated with the occurrence of flooding the city.

  5. Integrated real-time roof monitoring

    Institute of Scientific and Technical Information of China (English)

    SHEN Bao-tang; GUO Hua; KING Andrew

    2009-01-01

    CSIRO has recently developed a real-time roof monitoring system for under-ground coal mines and successfully tried the system in gate roads at Ulan Mine. The sys-tem integrated displacement monitoring, stress monitoring and seismic monitoring in one package. It included GEL multianchor extensometers, vibrating wire uniaxial stress meters, ESG seismic monitoring system with microseismic sensors and high-frequency AE sen-sors. The monitoring system automated and the data can be automatically collected by a central computer located in an underground nonhazardous area. The data are then trans-ferred to the surface via an optical fiber cable. The real-time data were accessed at any location with an Internet connection. The trials of the system in two tailgates at Ulan Mine demonstrate that the system is effective for monitoring the behavior and stability of read-ways during Iongwall mining. The continuous roof displacement/stress data show clear precursors of roof falls. The seismic data (event count and locations) provide insights into the roof failure process during roof fall.

  6. Fuel Consumption Impacts of Auto Roof Racks

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yuche; Meier, Alan

    2016-05-01

    The after-market roof rack is one of the most common components attached to a vehicle for carrying over-sized items, such as bicycles and skis. It is important to understand these racks' fuel consumption impacts on both individual vehicles and the national fleet because they are widely used. We estimate the national fuel consumption impacts of roof racks using a bottom-up approach. Our model incorporates real-world data and vehicle stock information to enable assessing fuel consumption impacts for several categories of vehicles, rack configurations, and usage conditions. In addition, the model draws on two new data-gathering techniques, on-line forums and crowd-sourcing. The results show that nationwide, roof racks are responsible for 0.8% of light duty vehicle fuel consumption in 2015, corresponding to 100 million gallons of gasoline per year. Sensitivity analyses show that results are most sensitive to the fraction of vehicles with installed roof racks but carrying no equipment. The aerodynamic efficiency of typical roof racks can be greatly improved and reduce individual vehicle fuel consumption; however, government policies to minimize extensive driving with empty racks--if successful--could save more fuel nationally.

  7. Roofing as a source of nonpoint water pollution.

    Science.gov (United States)

    Chang, Mingteh; McBroom, Matthew W; Scott Beasley, R

    2004-12-01

    Sixteen wooden structures with two roofs each were installed to study runoff quality for four commonly used roofing materials (wood shingle, composition shingle, painted aluminum, and galvanized iron) at Nacogdoches, Texas. Each roof, either facing NW or SE, was 1.22 m wide x 3.66 m long with a 25.8% roof slope. Thus, there were 32 alternatively arranged roofs, consisting of four roof types x two aspects x four replicates, in the study. Runoff from the roofs was collected through galvanized gutters, downspouts, and splitters. The roof runoff was compared to rainwater collected by a wet/dry acid rain collector for the concentrations of eight water quality variables, i.e. Cu(2+), Mn(2+), Pb(2+), Zn(2+), Mg(2+), Al(3+), EC and pH. Based on 31 storms collected between October 1997 and December 1998, the results showed: (1) concentrations of pH, Cu, and Zn in rainwater already exceed the EPA freshwater quality standards even without pollutant inputs from roofs, (2) Zn and Cu, the two most serious pollutants in roof runoff, exceeded the EPA national freshwater water quality standards in virtually 100% and more than 60% of the samples, respectively, (3) pH, EC, and Zn were the only three variables significantly affected by roofing materials, (4) differences in Zn concentrations were significant among all roof types and between all roof runoff and rainwater samples, (5) although there were no differences in Cu concentrations among all roof types and between roof runoff and rainwater, all means and medians of runoff and rainwater exceeded the national water quality standards, (6) water quality from wood shingles was the worst among the roof types studied, and (7) although SE is the most frequent and NW the least frequent direction for incoming storms, only EC, Mg, Mn, and Zn in wood shingle runoff from the SE were significantly higher than those from the NW; the two aspects affected no other elements in runoff from the other three roof types. Also, Zn concentrations from

  8. Floating attenuator wave energy device. Wavegen HYDRA project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The Wavegen Project which set out to develop a floating externally tensioned articulated wave-energy generator based on work carried out at RMCS Shrivenham in the 1980s has been abandoned until further notice. The computer modelling carried out in the early days indicated much promise, but the promise turned to disappointment when difficulties cropped-up in attempting to put the design into practice. A particular problem arose in matching the external tension to an equivalent beam stiffness to tune the natural bending frequency of the raft to that of the driving waves. A further eleven practical problems encountered are discussed.

  9. Feasibility design of a floating airport and estimation of environmental forces on it; Futaishiki kuko no sekkei to kankyo gairyoku no suitei ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Tabeta, S.; Takei, Y. [Yokohama National University, Yokohama (Japan). Faculty of Engineering

    1996-12-31

    A rough design was performed on a floating airport. On this floating structure, environmental external force was estimated, mooring design was carried out, and discussions was given on the position retaining performance important for airport functions and behavior of the floating structure. The discussion was given on cases that the airport is surrounded and not surrounded by floating breakwaters. A floating structure which becomes super-large in size requires considerations on force due to sea level gradient as a result of a tide. Deriving flow condition changes and force acting on the floating structure simultaneously by using numerical calculations makes it possible to estimate current force given with considerations on influence of the flow conditions created by installing the floating airport. Estimation was carried out by using a zone dividing method on wave drifting force acting upon the floating airport. As a result, it was found that installing floating and permeating type breakwaters can reduce the wave drifting force acting on the floating airport. The wave drifting force working on the floating airport can be reduced by installing the floating and permeating type breakwaters to lower levels than when no such breakwaters are installed. The airport may be moored with less number of fenders when the fenders of the same type are used. 18 refs., 10 figs., 5 tabs.

  10. Green Roofs and Green Building Rating Systems

    Directory of Open Access Journals (Sweden)

    Liaw

    2015-01-01

    Full Text Available The environmental benefits for green building from the Leadership in Energy and Environment Design (LEED and Ecology, Energy, Waste, and Health (EEWH rating systems have been extensively investigated; however, the effect of green roofs on the credit-earning mechanisms is relatively unexplored. This study is concerned with the environmental benefits of green roofs with respect to sustainability, stormwater control, energy savings, and water resources. We focused on the relationship between green coverage and the credits of the rating systems, evaluated the credits efficiency, and performed cost analysis. As an example, we used a university building in Keelung, Northern Taiwan. The findings suggest that with EEWH, the proposed green coverage is 50–75%, whereas with LEED, the proposed green coverage is 100%. These findings have implications for the application of green roofs in green building.

  11. Flat roof integration. CPT solar (AET IV)

    Energy Technology Data Exchange (ETDEWEB)

    Chianese, D.; Pola, I.; Bernasconi, A.; Bura, E.; Cereghetti, N.; Realini, A.; Pasinelli, P.; Rioggi, S.

    2007-11-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at a 15.4 kWp solar power installation in Trevano, Switzerland, that features flexible amorphous silicon triple-junction modules, mounted nearly horizontally and directly laminated to flexible polyolefin membranes that form the covering of a flat roof. The main objective of this study was to verify in which order of magnitude the better thermal behaviour of amorphous silicon cells can compensate for losses due to the quasi-horizontal roof integration (lower irradiation and higher reflection), and thus be competitive in the flat roof construction and refurbishment markets. The modules used and their characteristics are described. Performance, temperature levels and energy-production are reviewed for the panels of the installation. The performance of the inverter used is also reviewed. Data on temperatures and production are presented in graphical form and optical losses are examined.

  12. Weathering of Roofing Materials-An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Berdahl, Paul; Akbari, Hashem; Levinson, Ronnen; Miller, William A.

    2006-03-30

    An overview of several aspects of the weathering of roofing materials is presented. Degradation of materials initiated by ultraviolet radiation is discussed for plastics used in roofing, as well as wood and asphalt. Elevated temperatures accelerate many deleterious chemical reactions and hasten diffusion of material components. Effects of moisture include decay of wood, acceleration of corrosion of metals, staining of clay, and freeze-thaw damage. Soiling of roofing materials causes objectionable stains and reduces the solar reflectance of reflective materials. (Soiling of non-reflective materials can also increase solar reflectance.) Soiling can be attributed to biological growth (e.g., cyanobacteria, fungi, algae), deposits of organic and mineral particles, and to the accumulation of flyash, hydrocarbons and soot from combustion.

  13. Artisanal fishing net float loss and a proposal for a float design solution

    Directory of Open Access Journals (Sweden)

    Paulo de Tarso Chaves

    2016-03-01

    Full Text Available Abstract Plastic floats from fishing nets are commonly found washed up on beaches in southern Brazil. They are usually broken and show signs of having been repaired. Characteristics of floats and interviews with fishermen suggest two main causes of float loss. First, collisions between active gear, bottom trawl nets for shrimp, and passive gear, drift nets for fish, destroy nets and release fragments of them, including floats. Second, the difficulty with which floats are inserted on the float rope of the nets when they are used near the surface. Floats are inserted to replace damaged or lost floats, or they may be removed if it is desired that the nets be used in deeper waters. Floats may thus be poorly fixed to the cables and lost. Here a new float design that offers greater safety in use and for the replacement of floats is described and tested.

  14. Effects of roof and rainwater characteristics on copper concentrations in roof runoff.

    Science.gov (United States)

    Bielmyer, Gretchen K; Arnold, W Ray; Tomasso, Joseph R; Isely, Jeff J; Klaine, Stephen J

    2012-05-01

    Copper sheeting is a common roofing material used in many parts of the world. However, copper dissolved from roof sheeting represents a source of copper ions to watersheds. Researchers have studied and recently developed a simple and efficient model to predict copper runoff rates. Important input parameters include precipitation amount, rain pH, and roof angle. We hypothesized that the length of a roof also positively correlates with copper concentration (thus, runoff rates) on the basis that runoff concentrations should positively correlate with contact time between acidic rain and the copper sheet. In this study, a novel system was designed to test and model the effects of roof length (length of roof from crown to the drip edge) on runoff copper concentrations relative to rain pH and roof angle. The system consisted of a flat-bottom copper trough mounted on an apparatus that allowed run length and slope to be varied. Water of known chemistry was trickled down the trough at a constant rate and sampled at the bottom. Consistent with other studies, as pH of the synthetic rainwater decreased, runoff copper concentrations increased. At all pH values tested, these results indicated that run length was more important in explaining variability in copper concentrations than was the roof slope. The regression equation with log-transformed data (R(2) = 0.873) accounted for slightly more variability than the equation with untransformed data (R(2) = 0.834). In log-transformed data, roof angle was not significant in predicting copper concentrations.

  15. Quality of Rainwater from Different Roof Material

    Directory of Open Access Journals (Sweden)

    Olaoye, R.A

    2012-08-01

    Full Text Available Roof material is an important consideration when designing a rainwater catchment system .This is because it affects the quality of the harvested rainwater which invariably affects the usage as potable or non potable.This study was carried out to determine the quality of rainwater from four different roofing materials (asbestos, aluminium, concrete and corrugated plastic within Ogbomosho North Local Government Area of Oyo State, Nigeria, between the months of July to October, 2011. The rainwater samples were taken to the laboratory and analyzed as recommended by Nigerian standard for Drinking Water Quality (NSDQW and World Health Organization (WHO.All the Physical and most of the chemical parameters analyzed conformed to the recommended standard value apart from chloride and total hardness value. Of interest is the rainwater sample from asbestos roofing sheet which had the highest mean value for pH (6.75, total hardness (84 – 86mg/l, aluminium concentration (3 – 9 mg/l, copper (0.03 – 0.04 mg/l, nitrate (31.9 – 39mg/l, and sulphate value between 11- 14mg/l, although, all these parameters fell within the standard values. However, Coliform as bacterial indicator was present in samples from asbestos, concrete and corrugated plastic roof, only the aluminium roof was free from pathogenic contamination. To ensure that the rainwater harvested satisfies health requirement for consumption as specified, all the harvested rainwater should be given some level of treatment in terms of pH, total hardness, chloride concentration and bacterial contamination. It was recommended that the rainwater from all the roofs in this case study area, be carefully examined. Consequently, if the harvested rainwater is being considered for domestic use, the gutters and the catchment areas should be regularly cleaned to remove animal droppings and leaves from over hanging trees as well as boiled to adequate temperature.

  16. Floating Cities, Islands and States

    CERN Document Server

    Bolonkin, Alexander

    2008-01-01

    Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating c...

  17. Weak roof fall simulation for a longwall face

    Energy Technology Data Exchange (ETDEWEB)

    Nazimko, V.V.; Khalimendick, U.M.; Zborshtchick, M.P.; Danilov, V.K.; Sugakov, V.A. [Donetsk State Technical University, Donetsk (Ukraine)

    1999-07-01

    A particle flow algorithm has been employed to investigate immediate roof stability. It is demonstrated that weak rock layers and a lack of powered supports are the most important factors which impact stability to the roof. 1 ref., 4 figs.

  18. Thermoplastic Single-Ply Roof Relieves Water Damage and Inconvenience.

    Science.gov (United States)

    Williams, Jennifer Lynn

    2002-01-01

    Assesses use of thermoplastic single-ply roofs by North Carolina's Mars Hill College to prevent leaks, reduce maintenance costs, and enhance the value of their older historic buildings. Administrators comment on the roof's installation efficiency and cleanliness. (GR)

  19. Stability analysis of subgrade cave roofs in karst region

    Institute of Scientific and Technical Information of China (English)

    蒋冲; 赵明华; 曹文贵

    2008-01-01

    According to the engineering features of subgrade cave roof in karst region, the clamped beam model of subgrade cave roof in karst region was set up. Based on the catastrophe theory, the cusp catastrophe model for bearing capacity of subgrade cave roof and safe thickness of subgrade cave roof in karst region was established. The necessary instability conditions of subgrade cave roof were deduced, and then the methods to determine safe thickness of cave roofs under piles and bearing capacity of subgrade cave roof were proposed. At the same time, a practical engineering project was applied to verifying this method, which has been proved successfu1ly. At last, the major factors that affect the stability on cave roof under pile in karst region were deeply discussed and some results in quality were acquired.

  20. Roof separation characteristics of laminated weak roof strata of longwall roadway

    Institute of Scientific and Technical Information of China (English)

    LU Ting-kan; LIU Yu-zhou

    2004-01-01

    The roof separation was investigated in a coal mine as part of the site characterization of roof strata deterioration in a longwall roadway. The separation of laminated,weak roof strata was initially characterized as the maximum separation, effect of geological setting on separation and the effect of mining activities (heading development,time-dependent and longwall extraction) on separation. Then the separation process was studied, so as to answer the questions of: when the separation occurs; where the separation is located and what geological setting it relates to; how large of the separation is; and how the separation propagates.

  1. The Benefits of Green Roofing for Latvian Building Environment

    OpenAIRE

    Kara, P.; Pastars, P

    2013-01-01

    Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife and helping to lower urban air temperatures and mitigate the heat island effect. The modern trend started when green roofs were developed in Germany in the 1960s, and has since spread to many countries. Today, it is estimated that about 10% of all German roofs have been “greened”. Green roofs are also becoming increasingly popular in the United States, although...

  2. The Self-Drying Concept for Flat Roofs

    DEFF Research Database (Denmark)

    Korsgaard, Vagn; Bunch-Nielsen, Tommy; Rode, Carsten

    1996-01-01

    Moisture in flat roof systems with an insulation layer has been a long-standing issue for the roof industry. It is now realised, that it is unrealistic and too costly to try to completely keep moisture from entering a roof assembly during its service life. The approach, therefore, should be to ke...... cold- and warm deck roof systems in climate zones where a vapor retarder is needed, if the traditional water proof vapor retarder is substituted by a water permeable vapor retarder....

  3. Airborne Exposures to Polycyclic Aromatic Compounds Among Workers in Asphalt Roofing Manufacturing Facilities.

    Science.gov (United States)

    Trumbore, David C; Osborn, Linda V; Johnson, Kathleen A; Fayerweather, William E

    2015-01-01

    We studied exposure of 151 workers to polycyclic aromatic compounds and asphalt emissions during the manufacturing of asphalt roofing products-including 64 workers from 10 asphalt plants producing oxidized, straight-run, cutback, and wax- or polymer-modified asphalts, and 87 workers from 11 roofing plants producing asphalt shingles and granulated roll roofing. The facilities were located throughout the United States and used asphalt from many refiners and crude oils. This article helps fill a gap in exposure data for asphalt roofing manufacturing workers by using a fluorescence technique that targets biologically active 4-6 ring polycyclic aromatic compounds and is strongly correlated with carcinogenic activity in animal studies. Worker exposures to polycyclic aromatic compounds were compared between manufacturing plants, at different temperatures and using different raw materials, and to important external benchmarks. High levels of fine limestone particulate in the plant air during roofing manufacturing increased polycyclic aromatic compound exposure, resulting in the hypothesis that the particulate brought adsorbed polycyclic aromatic compounds to the worker breathing zone. Elevated asphalt temperatures increased exposures during the pouring of asphalt. Co-exposures in these workplaces which act as confounders for both the measurement of total organic matter and fluorescence were detected and their influence discussed. Exposures to polycyclic aromatic compounds in asphalt roofing manufacturing facilities were lower than or similar to those reported in hot-mix paving application studies, and much below those reported in studies of hot application of built-up roofing asphalt. These relatively low exposures in manufacturing are primarily attributed to air emission controls in the facilities, and the relatively moderate temperatures, compared to built-up roofing, used in these facilities for oxidized asphalt. The exposure to polycyclic aromatic compounds was a very

  4. Study of Falling Roof Vibrations in a Production Face at Roof Support Resistance in the Form of Concentrated Force

    Science.gov (United States)

    Buyalich, G. D.; Buyalich, K. G.; Umrikhina, V. Yu

    2016-08-01

    One of the main reasons of roof support failures in production faces is mismatch of their parameters and parameters of dynamic impact on the metal structure from the falling roof during its secondary convergences. To assess the parameters of vibrational interaction of roof support with the roof, it was suggested to use computational models of forces application and a partial differential equation of fourth order describing this process, its numerical solution allowed to assess frequency, amplitude and speed of roof strata movement depending on physical and mechanical properties of the roof strata as well as on load bearing and geometry parameters of the roof support. To simplify solving of the differential equation, roof support response was taken as the concentrated force.

  5. 40 CFR 63.1042 - Standards-Separator fixed roof.

    Science.gov (United States)

    2010-07-01

    ...) National Emission Standards for Oil-Water Separators and Organic-Water Separators § 63.1042 Standards... controlling air emissions from an oil-water separator or organic-water separator using a fixed roof. (b) The... interface of the roof edge and the separator wall. (3) Each opening in the fixed roof shall be equipped...

  6. Recovery and reuse of asphalt roofing waste. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Desai, S.; Graziano, G.; Shepherd, P.

    1984-02-02

    Burning of asphalt roofing waste as a fuel and incorporating asphalt roofing waste in bituminous paving were identified as the two outstanding resource recovery concepts out of ten studied. Four additional concepts might be worth considering under different market or technical circumstances. Another four concepts were rated as worth no further consideration at this time. This study of the recovery of the resource represented in asphalt roofing waste has identified the sources and quantities of roofing waste. About six million cubic yards of scrap roofing are generated annually in the United States, about 94% from removal of old roofing at the job site and the remainder from roofing material production at factories. Waste disposal is a growing problem for manufacturers and contractors. Nearly all roofing waste is hauled to landfills at a considerable expense to roofing contractors and manufacturers. Recovery of the roofing waste resource should require only a modest economic incentive. The asphalt contained in roofing waste represents an energy resource of more than 7 x 10/sup 13/ Btu/year. Another 1 x 10/sup 13/ Btu/year may be contained in field-applied asphalt on commercial building roofs. The two concepts recommended by this study appear to offer the broadest applicability, the most favorable economics, and the highest potential for near-term implementation to reuse this resource.

  7. Green Roof Technology- Mitigate Urban Heat Island (UHI Effect

    Directory of Open Access Journals (Sweden)

    Odli Z.S. M.

    2016-01-01

    Full Text Available Alterations on the land surfaces, which are attributed by human activities, especially in cities, cause many implications to the ecosystem. The increase of buildings in cities is reflecting the growth of human activities resulted in a significant temperature increase and warmer pattern in the urban area than the surrounding countryside. The phenomenon defined as urban heat island. This study investigates the application and efficiency of the green roof as an approach to mitigate urban heat island and reducing indoor temperature in a building. Two types of roof models, which consist of vegetative roof and non-vegetative roof, were built to investigate the efficiency of vegetated roof in reducing indoor temperature compared to the non-vegetated roof. The outdoor and indoor temperature and humidity of each roof model were monitored by using RH520 Thermo Hygrometer. The data was collected for three times in a week for 9 weeks at 9:00am to 5:00pm. It was found that the indoor average temperature data for vegetative roof could be reduced 2.4°C from the outdoor average temperature and 0.8°C for non-vegetative roof. The difference of temperature reduction for vegetative roof was greater than the nonvegetative roof, thus indicate that green roof was highly efficient in reducing indoor temperature and mitigate urban heat island impact.

  8. Green roof establishment in extreme conditions : two case studies

    Energy Technology Data Exchange (ETDEWEB)

    Grothe, R. [Aloha Landscaping, Inc., Mendota Heights, MN (United States); Trichie, J. [Shakopee Mdewakanton Sioux Community, MN (United States)

    2007-07-01

    Green roof construction in the United States is growing at a rate of 60 to 80 per cent per year. This paper presented two case studies of green roof construction in Minnesota. In both cases, construction and budgeting delays moved the installation of the green roofs from early-May to mid-July. The first case study was a 20,000 square foot extensive green roof on the new Minneapolis Central Library which was completed in 2005. The second case study was a 30,000 square foot extensive green roof on the Mdewakanton Sioux Waste Water Treatment Plant in Shakopee, which was completed in 2006. This paper demonstrated that in order for green roofs to serve the functions for which they were intended, clear guidelines and specifications are needed to ensure that they are healthy. The size and locations of the two roofs were quite different, but they were identical in terms of waterproofing. State-of-the-art inverted hot-applied roof membrane technology was used in both roofs along with sub-surface irrigation systems. A mycorrhizae fungi was used in both cases to amend the growing medium. Both roofs used a diverse pallet of native and traditional sedum plant material. This paper highlighted preventative measures taken to ensure the successful installation and establishment of the two roofs built during extreme heat and drought-like conditions. The positive results confirm that it is possible to install green roofs during extremely harsh summer conditions. 9 refs., 4 tabs., 3 figs.

  9. 30 CFR 75.211 - Roof testing and scaling.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Roof testing and scaling. 75.211 Section 75.211 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.211 Roof testing and scaling. (a)...

  10. Causes of falls of roof in South African collieries

    CSIR Research Space (South Africa)

    Van der Merwe, JN

    2001-08-01

    Full Text Available on ta l s tre ss W ea th er ing Ba d m ini ng Dy ke s Bu rn t c oa l Contribution (% ) All Skin Large Major Figure 25. Causes of roof falls seen against the background of thickness of roof falls. 24 10 Influence of roof rock...

  11. 30 CFR 75.204 - Roof bolting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Roof bolting. 75.204 Section 75.204 Mineral... or the equivalent may be used. (3) Bearing plates used with wood or metal materials shall be at least... against wood; or (ii) Have exceeded the maximum specified torque or tension by 50 percent. (6) The...

  12. Accidents due to falls from roof slabs

    Directory of Open Access Journals (Sweden)

    Bruno Alves Rudelli

    Full Text Available CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%. Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%, and flying a kite was the most prevalent game (37.9%. In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  13. One Roof Judicial System in Indonesia

    Directory of Open Access Journals (Sweden)

    - Sufiarina

    2012-09-01

    Full Text Available Judicial power as an independent and autonomous power must be free from any intervention and power, thus ensuring that judges possess independence and impartiality in handling cases. One of the measures for enhancing the independence and autonomy of the judiciary is by placing it under the one roof judicial arrangement developed by the Supreme Court, both from the judicial as well as the non-judicial technical aspects. Up to the present time, endeavors for bringing the four court jurisdictions under the one roof judicial arrangement developed by the Supreme Court have not been completely materialized, due to the existing dualism in judicial power at various courts. The objective of this research is to understand the developments in the endeavors towards bringing the Indonesian judicial system under the one roof judicial arrangement developed by the Supreme Court. The type of research applied is descriptive normative juridical research, namely legal research based on examining secondary data. As the research results indicate, the one roof system developed by the Supreme Court is already being implemented, with the exception of the Military Court and the Tax Court within the State Administration Court jurisdiction.

  14. Load-Bearing Capacity of Roof Trusses

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Damkilde, Lars; Munch-Andersen, J.

    2004-01-01

    systems such as roof trusses are established and statistical characteristics of the load bearing capacity are determined. The results show that there is a significant increase in the characteristic (nominal) value and a reduction in the coefficient of variation (COV) for typical loads such as permanent...

  15. Accidents due to falls from roof slabs.

    Science.gov (United States)

    Rudelli, Bruno Alves; Silva, Marcelo Valerio Alabarce da; Akkari, Miguel; Santili, Claudio

    2013-01-01

    CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%). Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%), and flying a kite was the most prevalent game (37.9%). In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  16. Evolution of cool-roof standards in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Akbari, Hashem; Levinson, Ronnen

    2008-07-11

    Roofs that have high solar reflectance and high thermal emittance stay cool in the sun. A roof with lower thermal emittance but exceptionally high solar reflectance can also stay cool in the sun. Substituting a cool roof for a noncool roof decreases cooling-electricity use, cooling-power demand, and cooling-equipment capacity requirements, while slightly increasing heating-energy consumption. Cool roofs can also lower citywide ambient air temperature in summer, slowing ozone formation and increasing human comfort. Provisions for cool roofs in energy-efficiency standards can promote the building- and climate-appropriate use of cool roofing technologies. Cool-roof requirements are designed to reduce building energy use, while energy-neutral cool-roof credits permit the use of less energy-efficient components (e.g., larger windows) in a building that has energy-saving cool roofs. Both types of measures can reduce the life-cycle cost of a building (initial cost plus lifetime energy cost). Since 1999, several widely used building energy-efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool-roof credits or requirements. This paper reviews the technical development of cool-roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discusses the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool-roof provisions can be used as models to address cool roofs in building energy-efficiency standards worldwide.

  17. Ecological Impacts of Replacing Traditional Roofs with Green Roofs in Two Urban Areas

    Directory of Open Access Journals (Sweden)

    Timothy Carter

    2008-01-01

    Full Text Available Urban land cover is dominated by impervious surface that degrades both terrestrial and aquatic ecosystems relative to predevelopment conditions. There are significant opportunities for designers of urban landscapes to use alternative land covers that have multiple functions, benefiting both human and nonhuman components of the urban ecosystem. Vegetated (green roofs are one form of alternative land cover that has shown the potential to provide a variety of ecological benefits in urban areas. We evaluated how stormwater retention, building energy and temperature, and rooftop habitat are influenced by the use of green roofs using test plots in Georgia and Massachusetts. Green roofs were shown to recreate part of the predevelopment hydrology through increasing interception, stormwater storage, evaporation, and transpiration on the rooftop and worked extremely well for small storm events. Temperature reductions were found on the green rooftop as compared to an asphalt surface, although other roof technologies that minimize temperatures, such as lighter colored membranes, provide similar benefits. Novel habitat was created on the rooftop, although the extent of this habitat was limited in part by plant survivability and the need for additional water inputs for diverse plant communities to survive. Despite the challenges, the green roof benefits reported here suggest that green roofs can be used effectively as a multifunctional land cover in urban areas.

  18. Status of cool roof standards in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Levinson, Ronnen

    2007-06-01

    Since 1999, several widely used building energy efficiency standards, including ASHRAE 90.1, ASHRAE 90.2, the International Energy Conservation Code, and California's Title 24 have adopted cool roof credits or requirements. We review the technical development of cool roof provisions in the ASHRAE 90.1, ASHRAE 90.2, and California Title 24 standards, and discuss the treatment of cool roofs in other standards and energy-efficiency programs. The techniques used to develop the ASHRAE and Title 24 cool roof provisions can be used as models to address cool roofs in building energy standards worldwide.

  19. Green roofs as a means of pollution abatement.

    Science.gov (United States)

    Rowe, D Bradley

    2011-01-01

    Green roofs involve growing vegetation on rooftops and are one tool that can help mitigate the negative effects of pollution. This review encompasses published research to date on how green roofs can help mitigate pollution, how green roof materials influence the magnitude of these benefits, and suggests future research directions. The discussion concentrates on how green roofs influence air pollution, carbon dioxide emissions, carbon sequestration, longevity of roofing membranes that result in fewer roofing materials in landfills, water quality of stormwater runoff, and noise pollution. Suggestions for future directions for research include plant selection, development of improved growing substrates, urban rooftop agriculture, water quality of runoff, supplemental irrigation, the use of grey water, air pollution, carbon sequestration, effects on human health, combining green roofs with complementary related technologies, and economics and policy issues.

  20. Renewable Energy Based Floating Power Generator (Rivers and Canals

    Directory of Open Access Journals (Sweden)

    Dr. J.R.Gandhi

    2016-02-01

    Full Text Available We have developed a stand alone, (river and canal water stream floating power generator system for village electrification, agriculture water pumping, bridge street lights and such other utilities. The system is the unique one of its kind as per our knowledge and various surveys. The physical structure of the system is made of the non corrosive and unbreakable materials like mild steel, fiber glass etc. It works, as it rotates in the water flow. It does not require any kind of the external electric grid power for its working. As the water flows, the specially designed blades of the system rotate in the direction of the flow and ultimately the consistent power is generated, this power can be used directly or it may be stored in battery and the utilized as and when required. No permanent installation, No pollution and environment friendly floating Pico turbine. The observations taken from the sight are tabulated and accordingly results are discussed.

  1. STUDIES ON THE LAW OF ROOF-COAL MOVEMENT BY USING THE ROOF-COAL CAVING METHOD

    Institute of Scientific and Technical Information of China (English)

    张海戈; 徐秉业; 沈新普; 王志勤

    1996-01-01

    In this paper, the law of roof-coal movement has been investigated through the fieldmeasurement, theoretical analysis and numerical calculation. Several results, which are of im-portant values for caving process, design of the supports, controlling end-face stability, raisingrecovery rate, realizing working face high output and other related aspects in practice, havebeen obtained. These results mainly include the following: roof-coal breaking curve of soft-coalseam, roof-coal movement curve of soft-coal and medium-hard coal seam, and roof-coal move-ment equation. The roof-coal caveability has been analyzed.

  2. Suggestions of promoting Jinan city roof greening construction%济南市推行屋顶绿化建设的建议

    Institute of Scientific and Technical Information of China (English)

    李艳伟

    2016-01-01

    With an discussion of the meaning of promoting roof greening,combining with internal and external roof greening construction status, the paper analyzes problems existing in Jinan roof greening construction,and puts forward roof greening construction countermeasures from aspects of broadcasting strength,formulating perfect norms and cultivating plants planting and so on,so as to improve city greening coverage rate.%论述了推广屋顶绿化建设的意义,结合国内外屋顶绿化建设的现状,分析了济南市屋顶绿化建设中存在的问题,从加大宣传力度、制定完善规范、培养绿植种类等方面,提出了屋顶绿化建设的对策,从而大幅度地提高城市绿化覆盖率.

  3. Establishing green roof infrastructure through environmental policy instruments.

    Science.gov (United States)

    Carter, Timothy; Fowler, Laurie

    2008-07-01

    Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated

  4. Establishing Green Roof Infrastructure Through Environmental Policy Instruments

    Science.gov (United States)

    Carter, Timothy; Fowler, Laurie

    2008-07-01

    Traditional construction practices provide little opportunity for environmental remediation to occur in urban areas. As concerns for environmental improvement in urban areas become more prevalent, innovative practices which create ecosystem services and ecologically functional land cover in cities will be in higher demand. Green roofs are a prime example of one of these practices. The past decade has seen the North American green roof industry rapidly expand through international green roof conferences, demonstration sites, case studies, and scientific research. This study evaluates existing international and North American green roof policies at the federal, municipal, and community levels. Green roof policies fall into a number of general categories, including direct and indirect regulation, direct and indirect financial incentives, and funding of demonstration or research projects. Advantages and disadvantages of each category are discussed. Salient features and a list of prompting standards common to successfully implemented green roof strategies are then distilled from these existing policies. By combining these features with data collected from an experimental green roof site in Athens, Georgia, the planning and regulatory framework for widespread green roof infrastructure can be developed. The authors propose policy instruments be multi-faceted and spatially focused, and also propose the following recommendations: (1) Identification of green roof overlay zones with specifications for green roofs built in these zones. This spatial analysis is important for prioritizing areas of the jurisdiction where green roofs will most efficiently function; (2) Offer financial incentives in the form of density credits and stormwater utility fee credits to help overcome the barriers to entry of the new technology; (3) Construct demonstration projects and institutionalize a commitment greening roofs on publicly-owned buildings as an effective way of establishing an educated

  5. Floating Charge%Floating Charge--浮动抵押

    Institute of Scientific and Technical Information of China (English)

    鲍为民

    2004-01-01

    "Floating Charge"来源于英美法系,它将担保设立在公司的全部财产之上(该担保甚至可及于公司未来之财产),在结晶前公司对财产享有处分权.通过介绍Floating Charge的创立和发展变化,从设定和实施两个方面详细考察了该制度的具体内涵.最后通过和大陆法系财团抵押制度的对比,提出应在我国引进浮动抵押,完善企业担保制度.

  6. High resolution rainfall – runoff measurement setup for green roof experiments in a tropical environment

    Directory of Open Access Journals (Sweden)

    T. Vergroesen

    2010-12-01

    Full Text Available This article describes the measurement setup that is used for green roof experiments in a tropical environment, the required data treatment to obtain reliable values of rainfall, runoff and evapotranspiration, and how to deal with external disturbances that can influence the experiment results. High resolution rainfall runoff measurements to identify, understand and properly model the relevant runoff processes in a green roof require both tailored equipment and data treatment. A tipping bucket rain gauge is calibrated for and installed to measure minute based rain intensities. A runoff measuring setup is developed that can accurately quantify the runoff up to 6 l/min, and has a high resolution in both time and volume. Two different measuring setups are used to verify the evapotranspiration that is derived from the rainfall and runoff measurements.

  7. Heat transfers in a double-skin roof ventilated by natural convection in summer time

    CERN Document Server

    Biwole, Pascal; Pompeo, C

    2013-01-01

    The double-skin roofs investigated in this paper are formed by adding a metallic screen on an existing sheet metal roof. The system enhances passive cooling of dwellings and can help diminishing power costs for air conditioning in summer or in tropical and arid countries. In this work, radiation, convection and conduction heat transfers are investigated. Depending on its surface properties, the screen reflects a large amount of oncoming solar radiation. Natural convection in the channel underneath drives off the residual heat. The bi-dimensional numerical simulation of the heat transfers through the double skin reveals the most important parameters for the system's efficiency. They are, by order of importance, the sheet metal surface emissivity, the screen internal and external surface emissivity, the insulation thickness and the inclination angle for a channel width over 6 cm. The influence of those parameters on Rayleigh and Nusselt numbers is also investigated. Temperature and air velocity profiles on seve...

  8. 78 FR 24990 - Approval and Promulgation of Implementation Plans; Ohio; Volatile Organic Compound Emission...

    Science.gov (United States)

    2013-04-29

    ... control technology (RACT) requirements of the Clean Air Act (Act). EPA proposed these rules for approval... roof tanks and external floating roof tanks.'', effective May 12, 2011. (D) Ohio Administrative...

  9. Improving the durability of flat roof constructions

    DEFF Research Database (Denmark)

    Rudbeck, Claus Christian; Svendsen, Sv Aa Højgaard

    1999-01-01

    Flat roof constructions are mainly used on commercial, institutional and industrial buildings, where insulation is placed on top of the load-bearing deck and then covered with a roof membrane. Through time, there is a risk that the membrane will allow water passage as holes might form due...... to weathering effects or physical loads. Water will then enter the insulation, and as a vapor retarder is normally found below the insulation thus trapping the water in the insulation, the leak can remain undetected for a long period. When the leak is finally discovered, the insulation has to be discharged...... of the system, thereby making it easier to detect leaks faster. When a leak is detected, the membrane is repaired locally. In order to remove water which has already entered the insulation, an air gap or a system of air channels between the deck and the insulation is subjected to forced ventilation with outdoor...

  10. PERFORMANCE OF AN EARTHQUAKE EXCITED ROOF DIAPHRAGM.

    Science.gov (United States)

    Celebi, M.; Brady, G.; Safak, E.; Converse, A.; ,

    1986-01-01

    The objective of this paper is to study the earthquake performance of the roof diaphragm of the West Valley College gymnasium in Saratoga, California through a complete set of acceleration records obtained during the 24 April 1984 Morgan Hill Earthquake (M equals 6. 1). The roof diaphragm of the 112 ft. multiplied by 144 ft. rectangular, symmetric gymnasium consists of 3/8 in. plywood over tongue-and-groove sheathing attached to steel trusses supported by reinforced concrete columns and walls. Three sensors placed in the direction of each of the axes of the diaphragm facilitate the evaluation of in-plane deformation of the diaphragm. Other sensors placed at ground level measure vertical and horizontal motion of the building floor, and consequently allow the calculation of the relative motion of the diaphragm with respect to the ground level.

  11. Creating a marketplace for green roofs in Chicago

    Energy Technology Data Exchange (ETDEWEB)

    Vitt Sale, L. [Wright and Co. Chicago, IL (United States); Berkshire, M. [City of Chicago, IL (United States)

    2004-07-01

    Since 2003, the Chicago Department of Planning and Development has been encouraging city developers to consider installing green roofs on buildings in Chicago, with the belief that this practice results in mitigation of the urban heat island effect, cleaner runoff leaving green roofs, sound attenuation, aesthetic value, oxygen production, and mitigation of carbon dioxide emissions. However, the benefits to developers, which include reduced stormwater runoff, extended roof life and energy savings, in total do not offset the first cost premium of a green roof. Despite this, and with no mandate requiring green roofs, the marketplace is growing. After seeing green roofs on a tour in Europe, the mayor of Chicago encouraged the first design and installation of a 20,300 square foot demonstration green roof in Chicago, and other city-sponsored pilot projects followed shortly after. Since then, the number of green roofs in Chicago has grown to over one million square feet. A map of Chicago showing locations of most of the projects was presented. It was suggested that lower prices for green roofs, higher energy costs and an inclination to invest in long-term strategies would accelerate the market. In an effort to engage the public in dialogue, the Department of Planning and Development held seminars to promote the benefits of green roofs . Participants had many questions about the applicability of green roofs to Chicago, expressing skepticism that Chicago's climate would provide the same benefits as in Europe. Other concerns were expressed regarding the devaluation of property values resulting from placing green roofs on buildings; doubts about roof leaks; maintenance practices; and, bugs and mold. Since the first cost premium of the system remains a question, most participants expressed interest in some kind of incentive program, but remained open-minded if benefits could be proved. 6 figs.

  12. Installation of a Roof Mounted Photovoltaic System

    Science.gov (United States)

    Lam, M.

    2015-12-01

    In order to create a safe and comfortable environment for students to learn, a lot of electricity, which is generated from coal fired power plants, is used. Therefore, ISF Academy, a school in Hong Kong with approximately 1,500 students, will be installing a rooftop photovoltaic (PV) system with 302 solar panels. Not only will these panels be used to power a classroom, they will also serve as an educational opportunity for students to learn about the importance of renewable energy technology and its uses. There were four different options for the installation of the solar panels, and the final choice was made based on the loading capacity of the roof, considering the fact that overstressing the roof could prove to be a safety hazard. Moreover, due to consideration of the risk of typhoons in Hong Kong, the solar panel PV system will include concrete plinths as counterweights - but not so much that the roof would be severely overstressed. During and after the installation of the PV system, students involved would be able to do multiple calculations, such as determining the reduction of the school's carbon footprint. This can allow students to learn about the impact renewable energy can have on the environment. Another project students can participate in includes measuring the efficiency of the solar panels and how much power can be produced per year, which in turn can help with calculate the amount of money saved per year and when we will achieve economic parity. In short, the installation of the roof mounted PV system will not only be able to help save money for the school but also provide learning opportunities for students studying at the ISF Academy.

  13. Experimental Polyurethane Foam Roof Systems - II.

    Science.gov (United States)

    1983-01-01

    reflect the effects of cloud cover, windspeed, and radiation from the roof during early morning and late evening hours. Measurement of the area under the...INN \\k I, N’. tlir’I’iii V A I \\’A SIurelS42r. K110i tlIe. I ct Ili Solair i imip .\\r nill. Kiw\\\\, tMe. I N I C(I’ 0)1,4 (IC, Ni’rtolk. \\.A ( ( I

  14. Roof timber for fortifying mining works

    Energy Technology Data Exchange (ETDEWEB)

    Shirokov, A.P.; Kuntsevich, V.IK.; Pishchulin, V.V.; Seryi, A.M.; Volkov, P.A.

    1981-05-15

    The roof timber for fortifying mining works includes spring-mounted hinged elements made from a special rolled metal. In order to increase the carrying capacity of the support by increasing the deformation threshold, the springs are mounted by their expanded section to the lower side of the hinge; their ends are connected in turn to the elements made from the special rolled metal on both sides of the hinge.

  15. EXTRUDED POLYSTYRENE FOAM IN FLAT ROOFS

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-09-01

    Full Text Available In our article we prove the necessity of applying thermal insulation with low water absorption and resistance and preserving mechanical and thermophysical properties in corrosive environment in flat roofs, where there is always a danger of penetrating condensed moisture into the structure. As such material we offered extruded polystyrene foam - heat-insulating polymer material with uniformly distributed closed cells. The products are used in the form of slab insulation and special items - for forming slopes and venting.

  16. The Clouds That Float By

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    AS I walk toward the autumn of my life, I begin to realize that everything in the world seems to have moved in a cycle, like the four seasons that continue to change and renew outside my window. But I am still seated in front of my window, observing the floating clouds at the ends of the earth. Some of them float from the future, some from the past. They join at the head and the tail of the universe; it is hard to tell the dragon’s head from the dragon’s tail. Things are always like this—the beginnings and the endings are sometimes interchangeable; the things that you think have gone by, have gone far away or completely vanished will suddenly appear before you like old acquaintances. Perhaps it might be the second generation accompanied by the shadows of the first.

  17. A CMOS floating point multiplier

    Science.gov (United States)

    Uya, M.; Kaneko, K.; Yasui, J.

    1984-10-01

    This paper describes a 32-bit CMOS floating point multiplier. The chip can perform 32-bit floating point multiplication (based on the proposed IEEE Standard format) and 24-bit fixed point multiplication (two's complement format) in less than 78.7 and 71.1 ns, respectively, and the typical power dissipation is 195 mW at 10 million operations per second. High-speed multiplication techniques - a modified Booth's allgorithm, a carry save adder scheme, a high-speed CMOS full adder, and a modified carry select adder - are used to achieve the above high performance. The chip is designed for compatibility with 16-bit microcomputer systems, and is fabricated in 2 micron n-well CMOS technology; it contains about 23000 transistors of 5.75 x 5.67 sq mm in size.

  18. Control of roofs difficult to break down

    Energy Technology Data Exchange (ETDEWEB)

    Lukashov, V.G.; Suslyakov, V.P.; Korobov, A.N.

    1981-03-01

    This paper describes a method of advanced torpedoing a roof difficult to break down at the Polysaevskaya coal mine. It consists in placing explosive charges in the roof ahead of the coal face. Three schemes were tested: boreholes were drilled parallel to the face, perpendicular or inclined at an angle to the face. Boreholes were 112 mm in diameter and their length ranged from 30 to 100 m, distance between the boreholes amounted to 20 m. 6ZhV ammonite explosive, 90 mm in diameter and 500 mm long, were used. Torpedos were 2 m long, and separated by 3 to 4 m long air pockets. When a roof characterized by a high compressive strength coefficient (about 10 on the Protod'yakonov scale) was torpedoed, 250 kg of ammonite were used for a borehole 80 m long, and 160 kg for a borehole 50 m long. When borehole length was reduced to 40 m explosive consumption decreased to 117 kg. In the case of rocks with compressive strength coefficient of 6, explosive amount was two times lower. In a coal mine in which an OKP-70 face system was used applying advanced torpedoing increased labor productivity of the face by 30% and reduced cost of mining by 42%. Number of work accidents was reduced 13 times. (In Russian)

  19. Floating VAWT wind farm concepts

    OpenAIRE

    Schmidt Paulsen, Uwe; Friis Pedersen, Troels; Vita, Luca

    2008-01-01

    The report contains proposals and descriptions of VAWTs of 200kW, 1MW, 5MW and 25MW sizes in terms of dimensions, weights, loads, and power production. Additionally a proposal of the use of each of these sizes in a concept description for a 100MW wind farm. Manufacture, transportation, installation, maintenance and operation of VAWTs are considered briefly. A summary on advantages and disadvantages of floating VAWTs is given.

  20. Thickness monitor for floated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, J.; Grecu, G.M.

    1989-10-31

    This patent describes apparatus for determining the thickness of a layer of aerated sludge floating on a layer of a heavier liquid in a tank. It comprises: a frame means which can be positioned to extend vertically into the tank; horizontally-extending indicator means supported by and moveable vertically with respect to a portion of the frame means extending vertically into the tank. The indicator means being selectively positionable at the highest level of sludge in the tank; horizontally-extending lower base means attached to the frame means at or near the bottom thereof; horizontally-extending upper base means attached to the frame means at or near the top thereof; and a line carrying a float means. The line being movable secured at the upper base means and the lower base means. The float means being floatable on the liquid and including a horizontally-extending portion presenting an upwardly directed generally planar surface, which surface will be parallel to the interface of the sludge and liquid.

  1. NC green roof stormwater quantity and quality field evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Moran, A.; Hunt, B.; Jennings, G. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Biological and Agricultural Engineering

    2004-07-01

    A study was conducted in an effort to establish design standards for green roofs in North Carolina (NC). It was conducted in light of recent regulations that require stormwater runoff to be treated by structural controls in urban development. Two extensive green roofs were constructed within the Neuse River Basin in order to estimate the per cent of precipitation retained by the green roof; estimate the per cent peak flow reduction; determine whether green roofs can be used as nutrient reduction best management practices (BMPs) and if so, what removal efficiency should be assigned to green roofs; identify green roof vegetation types that thrive in central and eastern NC and find an optimal depth of soil for desirable plant growth. The determining factors for greater water retention were found to be soil depth and plant selection. BMPs such as bioretention areas, wet and dry detention ponds, constructed wetlands, and sand filters are commonly seen throughout NC. A new option for BMPs is the green roof to use thousands of square feet available on rooftops that would not otherwise be available on the ground. Each green roof in this study retained about 60 per cent of the total recorded rainfall during a nine-month observation period. The average peak flow reduction for both green roofs was about 85 per cent. Water quality data indicated that higher concentrations of total nitrogen and total phosphorous were present in the green roof runoff than in the control roof runoff and in the rainfall at each green roof site. This may be a result of N and P leaching from the soil media, which was composed of 15 per cent compost. It was suggested that leaching could be reduced with less organic matter present in the soil media. 12 refs., 1 tab., 8 figs.

  2. Research on hydraulic-powered roof supports test problems

    Institute of Scientific and Technical Information of China (English)

    SUN Hong-bo; JIANG Jin-qiu; MA Qiang

    2011-01-01

    The load-bearing characters of hydraulic-powered roof support with dual telescopic legs were analyzed. With a specific type hydraulic-powered roof support with dual telescopic legs for research object, the inside load test problems in factories was analyzed, and the correct test methods were given, which can enhance the test efficiency and make the factories away from the error design of hydraulic-powered roof supports and legs.

  3. Reviewing Green roof design approaches: Case study of residential buildings

    OpenAIRE

    Özarısoy, Bertuğ

    2013-01-01

    ABSTRACT: High density of the residential areas and steep land value in the cities have driven people to maximize liveable and productive spaces in urban settings. This includes the reinvention of roof functions extending merely as a protection from the elements to a platform of housing green building technologies such as green roofs. Increased interest in green roofs have led to advances in technology. An entire industry has sprung up which specializes in lightweight growing materials, ro...

  4. 14 CFR 27.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 27.753 Section...

  5. 14 CFR 29.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 29.753 Section...

  6. Floating microparticles based on low density foam powder.

    Science.gov (United States)

    Streubel, A; Siepmann, J; Bodmeier, R

    2002-07-25

    The aim of this study was to develop a novel multiparticulate gastroretentive drug delivery system and to demonstrate its performance in vitro. Floating microparticles consisting of (i) polypropylene foam powder; (ii) verapamil HCl as model drug; and (iii) Eudragit RS, ethylcellulose (EC) or polymethyl methacrylate (PMMA) as polymers were prepared with an O/W solvent evaporation method. The effect of various formulation and processing parameters on the internal and external particle morphology, drug loading, in vitro floating behavior, in vitro drug release kinetics, particle size distribution and physical state of the incorporated drug was studied. The microparticles were irregular in shape and highly porous. The drug encapsulation efficiency was high and almost independent of the theoretical loading. Encapsulation efficiencies close to 100% could be achieved by varying either the ratio 'amount of ingredients: volume of the organic phase' or the relative amount of polymer. In all cases, good in vitro floating behavior was observed. The release rate increased with increasing drug loading and with decreasing polymer amounts. The type of polymer significantly affected the drug release rate, which increased in the following rank order: PMMA

  7. Storm Water Retention on Three Green Roofs with Distinct Climates

    Science.gov (United States)

    Breach, P. A.; Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.; Powers, B. S. C.

    2014-12-01

    As urbanization continues to increase the impact of cities on their surrounding environments, the feasibility of implementing low-impact development such as green roofs is of increasing interest. Green roofs retain and attenuate storm water thereby reducing the load on urban sewer systems. In addition, green roofs can provide insulation and lower roof surface temperature leading to a decrease in building energy load. Green roof technology in North American urban environments remains underused, in part due to a lack of climate appropriate green roof design guidelines. The capacity of a green roof to moderate runoff depends on the storage capacity of the growing medium at the start of a rainfall event. Storage capacity is finite, which makes rapid drainage and evapotranspiration loss critical for maximizing storage capacity between subsequent storms. Here the retention and attenuation of storm events are quantified for experimental green roof sites located in three representative Canadian climates corresponding to; semiarid conditions in Calgary, Alberta, moderate conditions in London, Ontario, and cool and humid conditions in Halifax, Nova Scotia. The storage recovery and storm water retention at each site is modelled using a modified water balance approach. Components of the water balance including evapotranspiration are predicted using climate data collected from 2012 to 2014 at each of the experimental sites. During the measurement period there were over 300 precipitation events ranging from small, frequent events (green roofs in their respective climates.

  8. Can green roofs provide habitat for urban bees (Hymenoptera: Apidae?

    Directory of Open Access Journals (Sweden)

    Laurence Packer

    2009-01-01

    Full Text Available Increasing urbanization of many regions of the world has resulted in the decline of suitable habitat for wild flora and fauna. Green roofs have been suggested as a potential avenue to provide patches of good-quality habitat in highly developed regions. In this study, we surveyed green roofs for bee diversity and abundance to determine their potential as quality habitats in an urban area for these important pollinators. By comparing various biodiversity measures between green roofs and ground-level sites, we show that green roofs provide habitat to many bee species. Implications for pollinator conservation and urban agricultural production are discussed.

  9. Green roofs in Germany : yesterday, today and tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Herman, R. [Anhalt Univ., Bernburg (Germany)

    2003-07-01

    This presentation provided a historical overview of the development of green roofs in Germany. Real interest in green roof technology in Germany began in the 1970s at which time specific guidelines for correct installation were established. In the past 20 years there has been a dramatic increase in the number of green roofs. The main market drivers were ecological concerns, energy and cost saving potential, as well as the need to manage storm water. Green roofs have an insulating effect, leading to energy savings. Some cities in Germany have implemented an incentive program whereby reductions on city water fees are allocated to owners of green roofs. Many business opportunities have been created by an increased interest in green roofs. The demand for lava, pumice, expanded clay, recycled roof tiles, crushed brick and other materials is being met by a new industry. There has been a noted increase in green roof systems and components, as well as installation and maintenance companies. It is expected that the ever increasing price for land in German cities along with an increasing population density will spur an even greater demand for green roofs. Germany is considered one of the greenest countries in the world, due to public concern for all forms of pollution, the maintenance of ecological balance, the preservation of flora and fauna, and a respect for nature. 6 refs.

  10. TECHNICAL CONSIDERATIONS FOR THE PLANNING OF ROOF GARDENS

    Directory of Open Access Journals (Sweden)

    Nizamettin KOÇ

    1998-01-01

    Full Text Available Increases in population, buildings, traffic density and air pollution is the most specific characteristics of metropol cities. These conditions effect the living quality negatively. That is why architectures and planners should find both aesthetic and functional planning approach in urban areas. Roof gardens, which affect positively urban ecology in many ways, have an important place in this approach. Planning aproach of roof gardens are rather different compare to ground level design. Structural elements under the roof gardens againist the infiltration of water. That is why it is important that roof garden plannings should have some layers shuclh as drainage, insulation, waterproofing, filter layers and irrigation andf drainage systems.

  11. STRUCTURE AND STABILITY OF MAIN ROOF AFTER ITS FRACTURE

    Institute of Scientific and Technical Information of China (English)

    朱德仁; 钱鸣高

    1990-01-01

    A serics of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall mining. Based on these modelings spatial structures of the main roof after its fracture are described, blocks of the fractured main roof are classified and their behaviors are analyzed in this paper. Additionally, two stability indexes of the structures are defined, and the factors affecting stability of the structures with different boundaries and geometric conditions are discussed.

  12. Surface Tension Supported Floating of Heavy Objects: Why Elongated Bodies Float Better?

    CERN Document Server

    Bormashenko, Edward

    2015-01-01

    Floating of bodies heavier than the supporting liquid is discussed. Floating of cylindrical, ellipsoidal bodies and rectangular plates possessing lateral dimensions smaller than the capillary length is treated. It is demonstrated that more elongated bodies of a fixed volume are better supported by capillary forces, due to the increase in the perimeter of the triple line. Thus, floating of metallic needles obtains reasonable explanation.

  13. COMPARATIVE STUDY OF DIFFERENT TYPES OF ROOF AND INDOOR TEMPERATURES IN TROPICAL CLIMATE

    Directory of Open Access Journals (Sweden)

    Mrs. M. Ponni

    2015-04-01

    Full Text Available A roof provides protection to be safe from direct sunlight. From the shelter, shadow alone is not expected. Durability, sustainability, less life cycle cost, and low maintenance cost are expected from a selected roof. The world has a thirst to have a best roof. No roof will fulfil the requirement of humanity since the climatic conditions are different. Hence the roof should be selected according to the prevailing climate. And the roof selection depends on the need, taste and the spending capability of the house owner. Thatched shed, tiles covered roof, light roofs either using galvanized sheets or asbestos sheets, painted or unpainted metal sheets, RCC, Green roof, Roof pond, insulated roof, reflective roof, and cool roof are the roofs so far brought into use. Whatever be the roof, it should provide thermal comfort. Thermal comfort is felt through the thermal experience of the occupants. Thermal experience depends on the indoor temperature. Energy efficiency of a building is highly based on the indoor ambient temperature. Energy efficiency in buildings is compelling, cost effective, saves money and useful to compromise resource energy shortage. A light roof named as Single Decker (SID and an insulated double roof using hybrid technique named as (DOD are taken for this study. Among the selected roofs the DOD provides a better thermal performance and thermal comfort. The study has been carried out for the summer peak period in April 2014. Thermal performance and indoor temperature of the DOD is compared with other roof studies.

  14. Cost Analysis of Roof-Only Air Sealing and Insulation Strategies on 1 1/2-Story Homes in Cold Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ojczyk, C. [NorthernSTAR, St. Paul, MN (United States)

    2014-12-01

    The External Thermal and Moisture Management System (ETMMS), typically seen in deep energy retrofits, is a valuable approach for the roof-only portions of existing homes, particularly the 1 ½-story home. It is effective in reducing energy loss through the building envelope, improving building durability, reducing ice dams, and providing opportunities to improve occupant comfort and health.

  15. Cost Analysis of Roof-Only Air Sealing and Insulation Strategies on 1 1/2-Story Homes in Cold Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ojczyk, C.

    2014-12-01

    The External Thermal and Moisture Management System (ETMMS), typically seen in deep energy retrofits, is a valuable approach for the roof-only portions of existing homes, particularly the 1 1/2-story home. It is effective in reducing energy loss through the building envelope, improving building durability, reducing ice dams, and providing opportunities to improve occupant comfort and health.

  16. Entire cities could benefit from green roofs : Heleen Mees is investigating how five metropolises are greenifying their roofs

    OpenAIRE

    Mees, Heleen

    2014-01-01

    Rotterdam is making good progress with its creation of green roofs. Heleen Mees, researcher at Utrecht University, drew this conclusion from her research, in which she compared the green roof policy of four different cities with that of Rotterdam. Rotterdam awards grants to those wishing to create a green roof, thereby helping to promote the general acceptance of green roofs in the city. However, the researcher thinks this policy should be followed up: “You can’t award grants forever.”

  17. The Energy Impact in Buildings of Vegetative Solutions for Extensive Green Roofs in Temperate Climates

    Directory of Open Access Journals (Sweden)

    Benedetta Barozzi

    2016-08-01

    Full Text Available Many bibliographical studies have highlighted the positive effects of green roofs as technological solutions both for new and renovated buildings. The one-year experimental monitoring campaign conducted has investigated, in detail, some aspects related to the surface temperature variation induced by the presence of different types of vegetation compared to traditional finishing systems for flat roofs and their impact from an energy and environmental point of view. The results obtained underlined how an appropriate vegetative solution selection can contribute to a significant reduction of the external surface temperatures (10 °C–20 °C for I > 500 W/m2 and 0 °C–5 °C for I < 500 W/m2, regardless of the season compared to traditional flat roofs. During the winter season, the thermal gradients of the planted surface temperatures are close to zero compared to the floor, except under special improving conditions. This entails a significant reduction of the energy loads from summer air conditioning, and an almost conservative behavior with respect to that from winter heating consumption. The analysis of the inside growing medium temperatures returned a further interesting datum, too: the temperature gradient with respect to surface temperature (annual average 4 °C–9 °C is a function of solar radiation and involves the insulating contribution of the soil.

  18. Green roof systems: a study of public attitudes and preferences in southern Spain.

    Science.gov (United States)

    Fernandez-Cañero, Rafael; Emilsson, Tobias; Fernandez-Barba, Carolina; Herrera Machuca, Miguel Ángel

    2013-10-15

    This study investigates people's preconceptions of green roofs and their visual preference for different green roof design alternatives in relation to behavioral, social and demographical variables. The investigation was performed as a visual preference study using digital images created to represent eight different alternatives: gravel roof, extensive green roof with Sedums not in flower, extensive green roof with sedums in bloom, semi-intensive green roof with sedums and ornamental grasses, semi-intensive green roof with shrubs, intensive green roof planted with a lawn, intensive green roof with succulent and trees and intensive green roof with shrubs and trees. Using a Likert-type scale, 450 respondents were asked to indicate their preference for each digital image. Results indicated that respondents' sociodemographic characteristics and childhood environmental background influenced their preferences toward different green roof types. Results also showed that green roofs with a more careful design, greater variety of vegetation structure, and more variety of colors were preferred over alternatives.

  19. Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares Velasco, P. C.

    2011-04-01

    This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

  20. 14 CFR 27.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft in...

  1. 14 CFR 29.751 - Main float buoyancy.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft...

  2. Hydroelasticity of a Floating Plate

    DEFF Research Database (Denmark)

    Chen, X.; Jensen, Jørgen Juncher; Cui, W.

    2003-01-01

    The membrane forces are included in the hydroelastic analysis of a floating plate undergoing large vertical deflections in regular monochromatic multidirectional waves. The first-order vertical displacements induced by the linear wave exciting forces are calculated by the mode expansion method...... in the frequency domain. The second-order vertical displacements induced by the membrane forces are calculated by the von Karman plate theory. The results show that the membrane contribution both in terms of the axial stresses and the effect on the bending stresses can be important...

  3. Floating patella associated with lymphoedema

    Science.gov (United States)

    Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George

    2015-01-01

    Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253

  4. Comparing wildlife habitat and biodiversity across green roof type

    Energy Technology Data Exchange (ETDEWEB)

    Coffman, R.R. [Oklahoma Univ., Tulsa, OK (United States). Dept. of Landscape Architecture

    2007-07-01

    Green roofs represent restorative practices within human dominated ecosystems. They create habitat, increase local biodiversity, and restore ecosystem function. Cities are now promoting this technology as a part of mitigation for the loss of local habitat, making the green roof necessary in sustainable development. While most green roofs create some form of habitat for local and migratory fauna, some systems are designed to provide specific habitat for species of concern. Despite this, little is actually known about the wildlife communities inhabiting green roofs. Only a few studies have provided broad taxa descriptions across a range of green roof habitats, and none have attempted to measure the biodiversity across green roof class. Therefore, this study examined two different vegetated roof systems representative of North America. They were constructed under alternative priorities such as energy, stormwater and aesthetics. The wildlife community appears to be a result of the green roof's physical composition. Wildlife community composition and biodiversity is expected be different yet comparable between the two general types of green roofs, known as extensive and intensive. This study recorded the community composition found in the two classes of ecoroofs and assessed biodiversity and similarity at the community and group taxa levels of insects, spiders and birds. Renyi family of diversity indices were used to compare the communities. They were further described through indices and ratios such as Shannon's, Simpson's, Sorenson and Morsita's. In general, community biodiversity was found to be slightly higher in the intensive green roof than the extensive green roof. 26 refs., 4 tabs., 4 figs.

  5. Roof renovation of buildings 128 and 129

    CERN Multimedia

    2015-01-01

    The roof renovation of buildings 128 and 129 is scheduled to take place from 17 August to 15 October 2015.   During this period, access to the "raw material" workshop will be limited and controlled due to asbestos removal. Collecting your orders directly from the building will be difficult, or even impossible, and urgent requests will be difficult to carry out. We therefore ask you to create your requests via EDH, so that delivery may be carried out as soon as possible. Thank you for your understanding. GS Department

  6. Load-Bearing Capacity of Roof Trusses

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Damkilde, Lars; Munch-Andersen, J.

    2004-01-01

    systems such as roof trusses are established and statistical characteristics of the load bearing capacity are determined. The results show that there is a significant increase in the characteristic (nominal) value and a reduction in the coefficient of variation (COV) for typical loads such as permanent......-sections with low strength and stiffness will generally not have large load effects. Further, there can be system effects due to non-linear material behavior. In this paper a stochastic model is established for the bending strength and stiffness of timber beams. Next, stochastic models for typical timber structural...

  7. The Geometric Theory of Roof Reflector Resonators

    Science.gov (United States)

    1976-12-01

    with solid state lasers, beginning in 1967. Soncini and Svelto (Refs 39 and 40) and Cubeddu, Polloni, Sacchi, and Svelto (Ref 11) have used pairs of 900...used by these authors is shown in Fig. 5. 13 In all experiments the output was found to be highly repeatable from pulse to pulse. Soncini and Svelto ...DeLang and Boumhuis (Fig. 4(b) ) and Soncini and Svelto (Fig. 5 ) have observed in their lasers are the samn except that iii the former the roof

  8. High Efficiency Solar Integrated Roof Membrane Product

    Energy Technology Data Exchange (ETDEWEB)

    Partyka, Eric; Shenoy, Anil

    2013-05-15

    This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

  9. DIFFERENT ROOF BEHAVIOUR UNDER DIFFERENT UPPER MINING BOUNDARY CONDITION IN DATONG

    Institute of Scientific and Technical Information of China (English)

    康立勋

    1997-01-01

    Understanding roof behaviour and immediate roof failure patterns of Iongwall face is a prerequisite for establishing correct roof control theory and appplying effective roof control measures. Roof behaviour and immediate roof failure pattern have a close relationship with upper mining boundary conditions of Iongwall face. According to actual situation of Datong Mining Area, upper mining boundary conditions of Iongwall face have been classified into 5 types in this paper. Roof behaviour and immediate roof failure pattern under each upper mining boundary condition are discussed in details.

  10. Integral design methodology for collaborative design of sustainable roofs

    NARCIS (Netherlands)

    Quanjel, E.M.C.J.

    2006-01-01

    Normally the roof is the part of building which gets minimal attention to use for integration with the comfort system of the building. This is striking, as the roof is an important possible building component for containing sustainable energy systems. The sustainable energy possible options are ofte

  11. Fourier analysis of conductive heat transfer for glazed roofing materials

    Energy Technology Data Exchange (ETDEWEB)

    Roslan, Nurhana Lyana; Bahaman, Nurfaradila; Almanan, Raja Noorliyana Raja; Ismail, Razidah [Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Zakaria, Nor Zaini [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2014-07-10

    For low-rise buildings, roof is the most exposed surface to solar radiation. The main mode of heat transfer from outdoor via the roof is conduction. The rate of heat transfer and the thermal impact is dependent on the thermophysical properties of roofing materials. Thus, it is important to analyze the heat distribution for the various types of roofing materials. The objectives of this paper are to obtain the Fourier series for the conductive heat transfer for two types of glazed roofing materials, namely polycarbonate and polyfilled, and also to determine the relationship between the ambient temperature and the conductive heat transfer for these materials. Ambient and surface temperature data were collected from an empirical field investigation in the campus of Universiti Teknologi MARA Shah Alam. The roofing materials were installed on free-standing structures in natural ventilation. Since the temperature data are generally periodic, Fourier series and numerical harmonic analysis are applied. Based on the 24-point harmonic analysis, the eleventh order harmonics is found to generate an adequate Fourier series expansion for both glazed roofing materials. In addition, there exists a linear relationship between the ambient temperature and the conductive heat transfer for both glazed roofing materials. Based on the gradient of the graphs, lower heat transfer is indicated through polyfilled. Thus polyfilled would have a lower thermal impact compared to polycarbonate.

  12. Green roof hydrologic performance and modeling: a review.

    Science.gov (United States)

    Li, Yanling; Babcock, Roger W

    2014-01-01

    Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology.

  13. Hydrologic Restoration in the Urban Environment Using Green Roofs

    Directory of Open Access Journals (Sweden)

    Anna Palla

    2010-04-01

    Full Text Available Loss of natural soil and vegetation within the urban environment can significantly affect the hydrologic cycle by increasing storm water runoff rates and volumes. In order to mitigate these modifications in urban areas engineered systems are developed, such as green roofs, to mimic and replace functions (evapo-transpiration, infiltration, percolation which have been altered due to the impact of human development. Green roofs, also known as vegetated roof covers, eco-roofs or nature roofs, are composite complex layered structures with specific environmental benefits. They are increasingly being used as a source control measure for urban storm water management. Indeed, they are able to re-establish the natural water cycle processes and to operate hydrologic control over storm water runoff with a derived peak flow attenuation, runoff volume reduction and increase of the time of concentration. Furthermore green roofs exhibit the capacity to reduce storm water pollution; they generally act as a storage device, consequently pollutants are accumulated in the substrate layer and released when intensive rainwater washes them out. In order to investigate the hydrologic response of a green roof, the University of Genova recently developed a joint laboratory and full-scale monitoring programme by installing a “controlled” laboratory test-bed with known rainfall input and a companion green roof experimental site (40 cm depth in the town of Genoa. In the paper, data collected during the monitoring programme are presented and compared with literature data.

  14. Requirements of inverted roofs with a drainage layer

    DEFF Research Database (Denmark)

    Leimer, Hans-Peter; Rode, Carsten; Künzel, Hartwig

    2005-01-01

    This contribution illustrates the application of the standard EN ISO 6946 regarding the heat loss of an inverted roof for different regions of Europe. An addendum to the standard (EN ISO 6946:1996/A1, 2003) introduces a correction to the thermal transmittance of inverted roofs due to rain water f...

  15. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  16. Hygrothermal Performance of West Coast Wood Deck Roofing System

    Energy Technology Data Exchange (ETDEWEB)

    Pallin, Simon B [ORNL; Kehrer, Manfred [ORNL; Desjarlais, Andre Omer [ORNL

    2014-02-01

    Simulations of roofing assemblies are necessary in order to understand and adequately predict actual the hygrothermal performance. At the request of GAF, simulations have been setup to verify the difference in performance between white and black roofing membrane colors in relation to critical moisture accumulation for traditional low slope wood deck roofing systems typically deployed in various western U.S. Climate Zones. The performance of these roof assemblies has been simulated in the hygrothermal calculation tool of WUFI, from which the result was evaluated based on a defined criterion for moisture safety. The criterion was defined as the maximum accepted water content for wood materials and the highest acceptable moisture accumulation rate in relation to the risk of rot. Based on the criterion, the roof assemblies were certified as being either safe, risky or assumed to fail. The roof assemblies were simulated in different western climates, with varying insulation thicknesses, two different types of wooden decking, applied with varying interior moisture load and with either a high or low solar absorptivity at the roof surface (black or white surface color). The results show that the performance of the studied roof assemblies differs with regard to all of the varying parameters, especially the climate and the indoor moisture load.

  17. Extensive Green Roof Research Program at Colorado State University

    Science.gov (United States)

    In the high elevation, semi-arid climate of Colorado, green roofs have not been scientifically tested. This research examined alternative plant species, media blends, and plant interactions on an existing modular extensive green roof in Denver, Colorado. Six plant species were ev...

  18. Corrosion-Resistant Roof with Integrated Photovoltaic Power System

    Science.gov (United States)

    2014-02-01

    metal roof panel are being monitored using a non-operational mockup of a PV module and roofing panel installed on the exposure rack. Four experi...conditions Examination of 1 year’s data downloaded from the corrosion sensors placed between the metal panel and PV module on the system mockup in

  19. The Discharge Coefficient of a Centre-Pivot Roof Window

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Afshari, Alireza; Nielsen, Peter V.

    2012-01-01

    value of discharge coefficient is used. The constant value of discharge coefficient leads to deceptive airflow estimation in the cases of centre-pivot roof windows. The object of this paper is to study and evaluate the discharge coefficient of the centre pivot roof window. Focus is given...

  20. U-value measurements on a roof window

    DEFF Research Database (Denmark)

    Duer, Karsten

    1998-01-01

    This report describes the results of the U-value measurements performed on a roof window. The work is as a part of the development of an ISO/CEN standard measuring procedure for roof windows.The measurements have been performed using the procedures given in ISO 12567 draft version 1998...

  1. Opportunities Green Roofs Can Offer Ghanaians and their Cities

    African Journals Online (AJOL)

    Lone Star College System

    2015-08-17

    Aug 17, 2015 ... Review. Green roofs: A possible best management practice for enhancing the ... development in Ghana in this era of climate change and variability. Key words: Green roof, .... mitigation of urban heat island effect and indoor energy consumption. ..... through buildings, air pollution, emission of greenhouse.

  2. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  3. Floating point numbers are real numbers

    OpenAIRE

    Mascarenhas, Walter F.

    2016-01-01

    Floating point arithmetic allows us to use a finite machine, the digital computer, to reach conclusions about models based on continuous mathematics. In this article we work in the other direction, that is, we present examples in which continuous mathematics leads to sharp, simple and new results about the evaluation of sums, square roots and dot products in floating point arithmetic.

  4. Towards sensible floating-point arithmetic

    Energy Technology Data Exchange (ETDEWEB)

    Cody, W.J.

    1980-01-01

    Efforts to promote the development of high-quality transportable numerical software show that few, if any, of the floating-point arithmetic systems in existing computers are completely satisfactory for serious numerical computation. Examination of the defects in these systems leads to specifications for a sensible floating-point system from a numerical analyst's viewpoint. 1 table.

  5. associated injuries and complications in floating knee management

    African Journals Online (AJOL)

    Traumatology Surgery, Cotonou Teaching Hospital, Republic of Bénin. Correspondence to: Dr. ... Keywords: Associated injuries, complications, Floating knee, Management .... floating knee: epidemiology, prognostic indicators. & outcome ...

  6. A Roof for the Lion's House

    Science.gov (United States)

    1978-01-01

    Fans of the National Football League's Detroit Lions don't worry about gameday weather. Their magnificent new Pontiac Stadium has a domed, air-supported, fabric roof that admits light but protects the playing field and patrons from the elements. The 80,000-seat "Silverdome" is the world's largest fabric-covered structure-and aerospace technology played an important part in its construction. The key to economical construction of the Silverdome-and many other types of buildings-is a spinoff of fiber glass Beta yarn coated with Teflon TFE fluorocarbon resin. The big advance it offers is permanency. Fabric structures-tents, for example have been around since the earliest years of human civilization. But their coverings-hides, canvas and more recently plastics-were considered temporary; though tough, these fabrics were subject to weather deterioration. Teflon TFE-coated Beta Fiberglas is virtually impervious to the effects of weather and sunlight and it won't stretch, shrink, mildew or rot, thus has exceptional longevity; it is also very strong, lightweight, flame resistant and requires no periodic cleaning, because dirt will not stick to the surface of Teflon TFE. And to top all that, it costs only 30 to 40 percent as much as conventional roofing.

  7. Greenbacks from green roofs: forging a new industry in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Peck, S. W.; Callaghan, C. [Peck and Associates, Toronto, ON (Canada); Bass, B. [Environment Canada, Toronto, ON (Canada); Kuhn, M. [Toronto, ON (Canada)

    1999-03-01

    This report provides a comprehensive review of the qualitative and quantitative benefits of green roof and vertical garden technologies, explains the nature of roof greening and green roof systems, examines the barriers to their more rapid diffusion into Canadian markets, and makes recommendations as to how how these barriers may be overcome. Two basic types of green roof systems, extensive and intensive, are identified. Extensive green roofs are characterized by their low weight, low capital cost and low maintenance. Intensive green roofs, by contrast, are heavier, more costly to establish, require intensive planting and higher maintenance. Both types of green roofs may be further subdivided into accessible or inaccessible. Accessible green roofs are flat, outdoor open spaces intended for use as gardens or terraces, while inaccessible roofs are only accessible for periodic maintenance. 'Vertical gardens' are a type of extensive green roof, characterized by the growing of plants on or up against the facade of buildings. The many benefits of green roof or vertical garden technologies include energy cost savings due to increased insulation and improved protection of the roof membrane, air quality improvements, new employment opportunities for a wide range of people including suppliers of roof membranes and related products, and social benefits such as improved aesthetics, health and horticultural therapy. Barriers to diffusion in Canada have been identified as lack of awareness, lack of incentives to implement, cost implications, lack of technical standards, few existing examples and risks associated with uncertainty. The recommendations to overcome market barriers are intended to address these barriers, i.e. they call for increased efforts to generate awareness through addressing the knowledge availability issue, and through high profile demonstration projects, government-sponsored technology diffusion, financial incentives to overcome cost-based barriers

  8. Floating plant dominance as a stable state

    Science.gov (United States)

    Scheffer, Marten; Szabó, Sándor; Gragnani, Alessandra; van Nes, Egbert H.; Rinaldi, Sergio; Kautsky, Nils; Norberg, Jon; Roijackers, Rudi M. M.; Franken, Rob J. M.

    2003-01-01

    Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we demonstrate that floating-plant dominance can be a self-stabilizing ecosystem state, which may explain its notorious persistence in many situations. Our results, based on experiments, field data, and models, represent evidence for alternative domains of attraction in ecosystems. An implication of our findings is that nutrient enrichment reduces the resilience of freshwater systems against a shift to floating-plant dominance. On the other hand, our results also suggest that a single drastic harvest of floating plants can induce a permanent shift to an alternative state dominated by rooted, submerged growth forms. PMID:12634429

  9. Thermal Behavior of Green Roofs Applied to Tropical Climate

    Directory of Open Access Journals (Sweden)

    Grace Tibério Cardoso

    2013-01-01

    Full Text Available The main goal of this paper is to present results on an experimental field about the green roofs thermal behavior, compared to other traditional roof covering systems. On the one hand, it intends to describe shortly the constructive system of a green roof with a lightweight building system, which has a sustainable building materials character and, on the other, it worries with the water reuse and with the run-off delay. The main methodological procedure adopted to study the thermal behavior of green roof was installing thermocouples to collect surface temperatures and indoor air, later comparing them with existing prototypes in an experimental plot. The thermal behavior analysis of cover systems was assessed by a representative episode of the climate fact, based on the dynamic climate approach. The experimental results from internal air temperature measurements show that the green roofs applied to warm and dry climates also provide an interesting time lag with surface and internal air temperature reduction.

  10. A pilot study to evaluate runoff quantity from green roofs.

    Science.gov (United States)

    Lee, Ju Young; Lee, Min Jung; Han, Mooyoung

    2015-04-01

    The use of green roofs is gaining increased recognition in many countries as a solution that can be used to improve environmental quality and reduce runoff quantity. To achieve these goals, pilot-scale green roof assemblies have been constructed and operated in an urban setting. From a stormwater management perspective, green roofs are 42.8-60.8% effective in reducing runoff for 200 mm soil depth and 13.8-34.4% effective in reducing runoff for 150 mm soil depth. By using Spearman rank correlation analysis, high rainfall intensity was shown to have a negative relationship with delayed occurrence time, demonstrating that the soil media in green roofs do not efficiently retain rainwater. Increasing the number of antecedent dry days can help to improve water retention capacity and delay occurrence time. From the viewpoint of runoff water quality, green roofs are regarded as the best management practice by filtration and adsorption through growth media (soil).

  11. Experimental analysis of green roof substrate detention characteristics.

    Science.gov (United States)

    Yio, Marcus H N; Stovin, Virginia; Werdin, Jörg; Vesuviano, Gianni

    2013-01-01

    Green roofs may make an important contribution to urban stormwater management. Rainfall-runoff models are required to evaluate green roof responses to specific rainfall inputs. The roof's hydrological response is a function of its configuration, with the substrate - or growing media - providing both retention and detention of rainfall. The objective of the research described here is to quantify the detention effects due to green roof substrates, and to propose a suitable hydrological modelling approach. Laboratory results from experimental detention tests on green roof substrates are presented. It is shown that detention increases with substrate depth and as a result of increasing substrate organic content. Model structures based on reservoir routing are evaluated, and it is found that a one-parameter reservoir routing model coupled with a parameter that describes the delay to start of runoff best fits the observed data. Preliminary findings support the hypothesis that the reservoir routing parameter values can be defined from the substrate's physical characteristics.

  12. APPLICATION OF THE ROOF DISTURBANCETO MONITORING AND PREDICTINGTHE GROUND PRESSURE

    Institute of Scientific and Technical Information of China (English)

    付国彬; 钱鸣高

    1992-01-01

    Based on study of the influence of main roof fracture on ground pressure,this paper considered the immediate roof as a semi-infinite long beam on a Winkler elastic foundation. In the model the coal seam is the foundation and the pressure caused by rnian roof deflection is the load.Having solved the model and analyzed relevant factors,the authors indicate that the disturbance caused by the breakage of the mian roof can be observed in both gates of iongwaii face and explain why it can be. The paper points out that the applicability of the method to obtain the disturbance information by measuring the loads on supports is wider than that by measuring the roof convergence rate. The results are useful for monitoring and predicting ground pressure.

  13. Modelling of green roof hydrological performance for urban drainage applications

    DEFF Research Database (Denmark)

    Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen

    2014-01-01

    Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes...... from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010–2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989...... and that the mean annual runoff is not linearly related to the storage. Green roofs have therefore the potential to be important parts of future urban stormwater management plans....

  14. Mobilization and distribution of lead originating from roof dust and wet deposition in a roof runoff system.

    Science.gov (United States)

    Yu, Jianghua; Yu, Haixia; Huang, Xiaogu

    2015-12-01

    In this research, the mobilization and distribution of lead originating in roof dust and wet deposition were investigated within a roof dust-rooftop-runoff system. The results indicated that lead from roof dust and wet deposition showed different transport dynamics in runoff system and that this process was significantly influenced by the rainfall intensity. Lead present in the roof dust could be easily washed off into the runoff, and nearly 60 % of the total lead content was present in particulate form. Most of the lead from the roof dust was transported during the late period of rainfall; however, the lead concentration was higher for several minutes at the rainfall beginning. Even though some of the lead from wet deposition, simulated with a standard isotope substance, was adsorbed onto adhered roof dust and/or retained on rooftop in runoff system, most of it (50-82 %) remained as dissolved lead in the runoff for rainfall events of varying intensity. Regarding the distribution of lead in the runoff system, the results indicated that it could be carried in the runoff in dissolved and particulate form, be adsorbed to adhered roof dust, or remain on the rooftop because of adsorption to the roof material. Lead from the different sources showed different distribution patterns that were also related to the rainfall intensity. Higher rainfall intensity resulted in a higher proportion of lead in the runoff and a lower proportion of lead remaining on the rooftop.

  15. Entire cities could benefit from green roofs : Heleen Mees is investigating how five metropolises are greenifying their roofs

    NARCIS (Netherlands)

    Mees, Heleen

    2014-01-01

    Rotterdam is making good progress with its creation of green roofs. Heleen Mees, researcher at Utrecht University, drew this conclusion from her research, in which she compared the green roof policy of four different cities with that of Rotterdam. Rotterdam awards grants to those wishing to create a

  16. Problems with plastered external heat insulation. Probleme mit verputzter Aussenwaermedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Epple, H.; Foglia, A.; Preisig, H.; Pfefferkorn, J.

    1984-01-01

    Concerning execution, maintenance and service life, walls with plastered external heat insulation constitute an economic method. Owing to experience gained with plastered external heat insulation, it is possible today to provide reliable information on requirements made on ground material and operational execution. The author intends to contribute to a prevention of defects by giving concise examples. A survey on different types of external heat insulation is followed by a treatment of the problem areas of roof-edge connection, base end under ground, modernization of old buildings and cracks in plaster. Principal statements are made concerning steam diffusion, planning, materials and execution.

  17. Multiprocessing system for performing floating point arithmetic operations

    Energy Technology Data Exchange (ETDEWEB)

    Nguyenphu, M.; Thatcher, L.E.

    1990-10-02

    This patent describes a data processing system. It comprises: a fixed point arithmetic processor means for performing fixed point arithmetic operations and including control means for decoding a floating point arithmetic instruction specifying a floating point arithmetic operation, and an addressing means for computing addresses for floating point data for the floating point operation from a memory means. The memory means for storing data and including means for receiving the addresses from the fixed point arithmetic processor means and providing the floating point data to a floating point arithmetic processor means; and the floating point arithmetic processor means for performing floating point arithmetic operations and including control means for decoding the floating point instruction and performing the specified floating point arithmetic operation upon the floating point data from the memory means.

  18. Stormwater quality from extensive green roofs in a subtropical region

    Science.gov (United States)

    Onis Pessoa, Jonas; Allasia, Daniel; Tassi, Rutineia; Vaz Viega, Juliana; Fensterseifer, Paula

    2016-04-01

    Green roofs have increasingly become an integral part of urban environments, mainly due to their aesthetic benefits, thermal comfort and efficiency in controlling excess runoff. However, the effects of this emerging technology in the qualitative characteristics of rainwater is still poorly understood. In this study was evaluated the effect of two different extensive green roofs (EGRs) and a traditional roof built with corrugated fiber cement sheets (control roof) in the quality of rainwater, in a subtropical climate area in the city of Santa Maria, in southern Brazil. The principal variant between the two EGRs were the type of plant species, time since construction, soil depth and the substrate characteristics. During the monitoring period of the experiment, between the months of April and December of 2015 fourteen rainfall events were selected for qualitative analysis of water from the three roofs and directly from rainfall. It was analyzed physical (turbidity, apparent color, true color, electrical conductivity, total solids, dissolved solids, suspended solids and temperature), chemical (pH, phosphate, total nitrogen, nitrate, nitrite, chloride, sulfate, BOD, iron and total hardness), heavy metals (copper, zinc, lead and chromium) and microbiological parameters (total coliforms and E. coli). It was also characterized the substrates used in both extensive green roofs. The results showed that the quality of the water drained from EGR s was directly influenced by their substrates (in turn containing significant levels of nutrients, organic matter and some metals). The passage of rainwater through green roofs and control roof resulted in the elevation of pH, allowing the conversion of the slightly acidic rainfall into basic water. Similarly, on both types of roofs occurred an increase of the values of most of the physical, chemical and microbiological parameters compared to rainwater. This same trend was observed for heavy metals, although with a much smaller degree

  19. Modelling and Simulation of Free Floating Pig for Different Pipeline Inclination Angles

    Directory of Open Access Journals (Sweden)

    Woldemichael Dereje Engida

    2016-01-01

    Full Text Available This paper presents a modelling and simulation of free floating pig to determine the flow parameters to avoid pig stalling in pigging operation. A free floating spherical shaped pig was design and equipped with necessary sensors to detect leak along the pipeline. The free floating pig does not have internal or external power supply to navigate through the pipeline. Instead, it is being driven by the flowing medium. In order to avoid stalling of the pig, it is essential to conduct simulation to determine the necessary flow parameters for different inclination angles. Accordingly, a pipeline section with inclination of 0°, 15°, 30°, 45°, 60°, 75°, and 90° were modelled and simulated using ANSYS FLUENT 15.0 with water and oil as working medium. For each case, the minimum velocity required to propel the free floating pig through the inclination were determined. In addition, the trajectory of the free floating pig has been visualized in the simulation.

  20. Adventures on the roof of the world

    Science.gov (United States)

    Leslie,, David M.

    2013-01-01

    To conduct field biology requires tenacity, grit, and flexibility; to endeavor to achieve conservation success requires patience, persistence, and passion. The essence of field biology and the hope for conservation success are both reflected admirably in George B. Schaller's most recent book, Tibet Wild: A Naturalist's Journeys on the Roof of the World. I can think of no living biologist who embodies these characteristics more than Schaller does. Nearly 80 years old, he still regularly treks in faraway lands, observing and recording the natural history of species that the vast majority of us will never see in the wild. Schaller is a vanguard, and Tibet Wild, like his other books, is a sentinel of urgent conservation need.

  1. A field study to evaluate runoff quality from green roofs.

    Science.gov (United States)

    Vijayaraghavan, K; Joshi, U M; Balasubramanian, R

    2012-03-15

    Green (vegetated) roofs are emerging as practical strategies to improve the environmental quality of cities. However, the impact of green roofs on the storm water quality remains a topic of concern to city planners and environmental policy makers. This study investigated whether green roofs act as a source or a sink of various metals (Na, K, Ca, Mg, Al, Fe, Cu, Cd, Pb, Zn, Mn, Cr, Ni, Li and Co), inorganic anions (NO3-, NO2-, PO4(3-), SO4(2-), Cl-, F- and Br-) and cation (NH4+). A series of green roof assemblies were constructed. Four different real rain events and several artificial rain events were considered for the study. Results showed that concentrations of most of the chemical components in runoff were highest during the beginning of rain events and subsided in the subsequent rain events. Some of the important components present in the runoff include Na, K, Ca, Mg, Li, Fe, Al, Cu, NO3-, PO4(3-) and SO4(2-). However, the concentration of these chemical components in the roof runoff strongly depends on the nature of substrates used in the green roof and the volume of rain. Based on the USEPA standards for freshwater quality, we conclude that the green roof used in this study is reasonably effective except that the runoff contains significant amounts of NO3- and PO4(3-).

  2. Comparative life cycle assessment of standard and green roofs.

    Science.gov (United States)

    Saiz, Susana; Kennedy, Christopher; Bass, Brad; Pressnail, Kim

    2006-07-01

    Life cycle assessment (LCA) is used to evaluate the benefits, primarily from reduced energy consumption, resulting from the addition of a green roof to an eight story residential building in Madrid. Building energy use is simulated and a bottom-up LCA is conducted assuming a 50 year building life. The key property of a green roof is its low solar absorptance, which causes lower surface temperature, thereby reducing the heat flux through the roof. Savings in annual energy use are just over 1%, but summer cooling load is reduced by over 6% and reductions in peak hour cooling load in the upper floors reach 25%. By replacing the common flat roof with a green roof, environmental impacts are reduced by between 1.0 and 5.3%. Similar reductions might be achieved by using a white roof with additional insulation for winter, but more substantial reductions are achieved if common use of green roofs leads to reductions in the urban heat island.

  3. Numerical analysis of application for induction caving roof

    Institute of Scientific and Technical Information of China (English)

    HU Jian-hua; ZHOU Ke-ping; LI Xi-bing; YANG Nian-ge; SU Jia-hong

    2005-01-01

    New method for handling roof of the base successive mining is proposed, which is induction caving in the roof. The key is that it is made certain to the station of the space-time in the induction caving roof, as the stress is released with the mining process. And applying the catastrophe theory, the influencing factors of induction caving roof are studied in the emptied areas, such as the mechanical property of the surrounding rock, the area of the gob,the scope and dimension of tensile stress. The results show that the key factor is the area of the gob to the method of the induction caving roof. Then according to the geology and the ore characteristic, the three dimension FEM mechanical model is built in Tongkeng Mine, the laws of the tensile stress are analyzed to the space and the time in the roof with the mining, then it is rational design to the mine step and time of the handing the roof.

  4. Chemical composition of water from roofs in Gdansk, Poland

    Energy Technology Data Exchange (ETDEWEB)

    Tsakovski, Stefan, E-mail: stsakovski@chem.uni-sofia.b [Chair of Physical Chemistry, Faculty of Chemistry, University of Sofia, J Bourchier Blvd. 1, 1164 Sofia (Bulgaria); Tobiszewski, Marek [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Simeonov, Vasil, E-mail: vsimeonov@chem.uni-sofia.b [Chair of Analytical Chemistry, Faculty of Chemistry, University of Sofia, 1164 Sofia (Bulgaria); Polkowska, Zaneta [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland); Namiesnik, Jacek, E-mail: chemanal@pg.gda.p [Department of Analytical Chemistry, Chemical Faculty, Gdansk University of Technology (GUT), 11/12 G. Narutowicza St., 80-952 Gdansk (Poland)

    2010-01-15

    This study deals with the assessment of roof runoff waters from the region of Gdansk collected during the winter season (2007/2008). The chemical analysis includes 16 chemical variables: major ions, PAHs and PCBs measured at 3 sampling sites for 6-14 rain events. Although the data set is of limited volume the statistical data treatment using self-organizing maps (SOM) reveals the main factors controlling roof runoff water quality even for a data set with small dimension. This effort for explanation of the identified factors by the possible emission sources of the urban environment and air-particulate formation seems to be very reliable. Additionally to the roof runoff water quality factors the rain events patterns are found: 'background' group of events and groups formally named 'PAHs', 'PCBs' and 'air-borne particles' - dominated events. The SOM classification results give an opportunity to uncover the role of roof 'impact' on the runoff waters. Rain runoff water quality is described by four latent factors and the 'roof' impact is uncovered. - Identification of the urban roof runoff water quality factors and 'roof' impact by self-organizing map classification.

  5. Multi functional roof structures of the energy efficient buildings

    Directory of Open Access Journals (Sweden)

    Krstić Aleksandra

    2006-01-01

    Full Text Available Modern architectural concepts, which are based on rational energy consumption of buildings and the use of solar energy as a renewable energy source, give the new and significant role to the roofs that become multifunctional structures. Various energy efficient roof structures and elements, beside the role of protection, provide thermal and electric energy supply, natural ventilation and cooling of a building, natural lighting of the indoor space sunbeam protection, water supply for technical use, thus according to the above mentioned functions, classification and analysis of such roof structures and elements are made in this paper. The search for new architectural values and optimization in total energy balance of a building or the likewise for the urban complex, gave to roofs the role of "climatic membranes". Contemporary roof forms and materials clearly exemplify their multifunctional features. There are numerous possibilities to achieve the new and attractive roof design which broadens to the whole construction. With such inducement, this paper principally analyze the configuration characteristics of the energy efficient roof structures and elements, as well as the visual effects that may be achieved by their application.

  6. Floating-point standards: Theory and practice

    Energy Technology Data Exchange (ETDEWEB)

    Cody, W.J.

    1987-01-01

    ANSI/IEEE Std 754-1985, the IEEE Standard for Binary Floating-Point Arithmetic, has now been joined by IEEE Std 854-1987, A Radix- Independent Standard for Floating-Point Arithmetic. These standards specify floating-point arithmetic systems that are intended to simplify the preparation of high-quality numerical software. The success of these standards hinges on how well they are implemented and how well they are supported by enhancements to algebraic languages. This paper briefly outlines the arithmetic systems specified by the standards, and discusses some existing implementations. 16 refs., 1 tab.

  7. Floating point arithmetic in future supercomputers

    Science.gov (United States)

    Bailey, David H.; Barton, John T.; Simon, Horst D.; Fouts, Martin J.

    1989-01-01

    Considerations in the floating-point design of a supercomputer are discussed. Particular attention is given to word size, hardware support for extended precision, format, and accuracy characteristics. These issues are discussed from the perspective of the Numerical Aerodynamic Simulation Systems Division at NASA Ames. The features believed to be most important for a future supercomputer floating-point design include: (1) a 64-bit IEEE floating-point format with 11 exponent bits, 52 mantissa bits, and one sign bit and (2) hardware support for reasonably fast double-precision arithmetic.

  8. New CFOA-based floating immittance emulators

    Science.gov (United States)

    Taher Abuelma'atti, Muhammad; Dhar, Sagar Kumar

    2016-12-01

    This paper presents four new topologies for emulating floating immittance functions. Each circuit uses two or three current-feedback operational-amplifiers (CFOAs) and three passive elements. The proposed topologies can emulate positive/negative lossless and lossy floating inductances, and positive/negative capacitance, resistance and inductance multipliers in addition to floating frequency-dependent positive and negative resistances. The functionality of the proposed circuits is verified using the Advanced Design System software and the AD844 CFOA. The simulation results are in excellent agreement with the theoretical calculations.

  9. Controlled decoherence of floating flux qubits

    Institute of Scientific and Technical Information of China (English)

    Ji Ying-Hua; Xu Lin

    2010-01-01

    In Born-Markov approximation, this paper calculates the energy relaxation time T1 and the decoherence time T2 of a floating flux qubit by solving the set of Bloch-Redfield equations. It shows that there are two main factors influencing the floating flux qubits: coupling capacitor in the circuit and the environment resistor. It also discusses how to improvethe quantum coherence time of a qubit. Through shunt connecting/series connecting inductive elements, an inductive environment resistor is obtained and further the reactance component of the environment resistor is improved, which is beneficial to the enhancement of decoherence time of floating flux qubits.

  10. Capillary floating and the billiard ball problem

    CERN Document Server

    Gutkin, Eugene

    2010-01-01

    We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cylinders that float in neutral equilibrium at any orientation with constant contact angles.

  11. Rainwater runoff retention on an aged intensive green roof.

    Science.gov (United States)

    Speak, A F; Rothwell, J J; Lindley, S J; Smith, C L

    2013-09-01

    Urban areas are characterised by large proportions of impervious surfaces which increases rainwater runoff and the potential for surface water flooding. Increased precipitation is predicted under current climate change projections, which will put further pressure on urban populations and infrastructure. Roof greening can be used within flood mitigation schemes to restore the urban hydrological balance of cities. Intensive green roofs, with their deeper substrates and higher plant biomass, are able to retain greater quantities of runoff, and there is a need for more studies on this less common type of green roof which also investigate the effect of factors such as age and vegetation composition. Runoff quantities from an aged intensive green roof in Manchester, UK, were analysed for 69 rainfall events, and compared to those on an adjacent paved roof. Average retention was 65.7% on the green roof and 33.6% on the bare roof. A comprehensive soil classification revealed the substrate, a mineral soil, to be in good general condition and also high in organic matter content which can increase the water holding capacity of soils. Large variation in the retention data made the use of predictive regression models unfeasible. This variation arose from complex interactions between Antecedant Dry Weather Period (ADWP), season, monthly weather trends, and rainfall duration, quantity and peak intensity. However, significantly lower retention was seen for high rainfall events, and in autumn, which had above average rainfall. The study period only covers one unusually wet year, so a longer study may uncover relationships to factors which can be applied to intensive roofs elsewhere. Annual rainfall retention for Manchester city centre could be increased by 2.3% by a 10% increase in intensive green roof construction. The results of this study will be of particular interest to practitioners implementing greenspace adaptation in temperate and cool maritime climates.

  12. Cool roofs as an energy conservation measure for federal buildings

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Haider; Akbari, Hashem

    2003-04-07

    We have developed initial estimates of the potential benefits of cool roofs on federal buildings and facilities (building scale) as well as extrapolated the results to all national facilities under the administration of the Federal Energy Management Program (FEMP). In addition, a spreadsheet ''calculator'' is devised to help FEMP estimate potential energy and cost savings of cool roof projects. Based on calculations for an average insulation level of R-11 for roofs, it is estimated that nationwide annual savings in energy costs will amount to $16M and $32M for two scenarios of increased roof albedo (moderate and high increases), respectively. These savings, corresponding to about 3.8 percent and 7.5 percent of the base energy costs for FEMP facilities, include the increased heating energy use (penalties) in winter. To keep the cost of conserved energy (CCE) under $0.08 kWh-1 as a nationwide average, the calculations suggest that the incremental cost for cool roofs should not exceed $0.06 ft-2, assuming that cool roofs have the same life span as their non-cool counterparts. However, cool roofs usually have extended life spans, e.g., 15-30 years versus 10 years for conventional roofs, and if the costs of re-roofing are also factored in, the cutoff incremental cost to keep CCE under $0.08 kWh-1 can be much higher. In between these two ends, there is of course a range of various combinations and options.

  13. A Novel Ideal Floating Inductor Using Translinear Conveyors

    Directory of Open Access Journals (Sweden)

    Iqbal A. Khan

    2003-01-01

    Full Text Available An ideal floating inductor circuit using translinear conveyors is introduced. The floating inductor simulator uses two translinear conveyors and a single capacitor in its realization. The circuit provides the current controlled ideal floating inductance without any component matching constraints. Simulation results on the floating inductor simulator verify the theory

  14. 14 CFR 23.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 23.753 Section 23.753... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main float must meet the requirements of § 23.521. ...

  15. An environmental cost-benefit analysis of alternative green roofing strategies

    Science.gov (United States)

    Richardson, M.; William, R. K.; Goodwell, A. E.; Le, P. V.; Kumar, P.; Stillwell, A. S.

    2016-12-01

    Green roofs and cool roofs are alternative roofing strategies that mitigate urban heat island effects and improve building energy performance. Green roofs consist of soil and vegetation layers that provide runoff reduction, thermal insulation, and potential natural habitat, but can require regular maintenance. Cool roofs involve a reflective layer that reflects more sunlight than traditional roofing materials, but require additional insulation during winter months. This study evaluates several roofing strategies in terms of energy performance, urban heat island mitigation, water consumption, and economic cost. We use MLCan, a multi-layer canopy model, to simulate irrigated and non-irrigated green roof cases with shallow and deep soil depths during the spring and early summer of 2012, a drought period in central Illinois. Due to the dry conditions studied, periodic irrigation is implemented in the model to evaluate its effect on evapotranspiration. We simulate traditional and cool roof scenarios by altering surface albedo and omitting vegetation and soil layers. We find that both green roofs and cool roofs significantly reduce surface temperature compared to the traditional roof simulation. Cool roof temperatures always remain below air temperature and, similar to traditional roofs, require low maintenance. Green roofs remain close to air temperature and also provide thermal insulation, runoff reduction, and carbon uptake, but might require irrigation during dry periods. Due to the longer lifetime of a green roof compared to cool and traditional roofs, we find that green roofs realize the highest long term cost savings under simulated conditions. However, using longer-life traditional roof materials (which have a higher upfront cost) can help decrease this price differential, making cool roofs the most affordable option due to the higher maintenance costs associated with green roofs

  16. The effects of green roofs in a sub-tropical system

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, M. [Austin Univ., Austin, TX (United States). Lady Bird Johnson Wildflower Center; Gardiner, B. [Austech Roof Consultants Inc., Austin, TX (United States)

    2007-07-01

    The building and environmental benefits of green roofs in non-temperate, or subtropical systems were discussed. Since there are greater climatic extremes in such systems, green roofs may offer more benefits. Most green roof research has focused on the use of succulent plants due to their low water demand and slow growth rates. The Lady Bird Johnson Wildflower Center and the Roof Consultants Institute Foundation are conducting joint research project to assess the suitability of native vegetation for use on extensive green roofs in central Texas. The project examined the effects of green roofing in a subtropical climate and the thermal properties of buildings, stormwater runoff rates, water quality, and irrigation requirements. Stormwater retention capacity of green roofs and water quality of stormwater runoff was compared to conventional roofs. The growing media that are most successful for this particular ecoregion was also identified. The focus on native plants in this study identified the characteristics of climatic adaptation, which may help to reduce total water and nutrient demand, and avoid problems associated with the introduction of potentially invasive species. The study compared performance of 6 types of green roofs and two types of traditional roof materials using simulated roof platforms. During the hottest days in August, roof membrane temperatures on the green roofs were 10 degrees C cooler than white roofs and 40 degrees C cooler than conventional black roofs. It was concluded that the temperature and water quantity characteristics of green roofs are advantageous in subtropical climates. 4 refs., 1 tab., 4 figs.

  17. Specifying, Installing and Maintaining Built-Up and Modified Bitumen Roofing Systems.

    Science.gov (United States)

    Hobson, Joseph W.

    2000-01-01

    Examines built-up, modified bitumen, and hybrid combinations of the two roofing systems and offers advise on how to assure high- quality performance and durability when using them. Included is a glossary of commercial roofing terms and asphalt roofing resources to aid in making decisions on roofing and systems product selection. (GR)

  18. Effects of Solar Photovoltaic Panels on Roof Heat Transfer

    Science.gov (United States)

    Dominguez, A.; Klessl, J.; Samady, M.; Luvall, J. C.

    2010-01-01

    Building Heating, Ventilation and Air Conditioning (HVAC) is a major contributor to urban energy use. In single story buildings with large surface area such as warehouses most of the heat enters through the roof. A rooftop modification that has not been examined experimentally is solar photovoltaic (PV) arrays. In California alone, several GW in residential and commercial rooftop PV are approved or in the planning stages. With the PV solar conversion efficiency ranging from 5-20% and a typical installed PV solar reflectance of 16-27%, 53-79% of the solar energy heats the panel. Most of this heat is then either transferred to the atmosphere or the building underneath. Consequently solar PV has indirect effects on roof heat transfer. The effect of rooftop PV systems on the building roof and indoor energy balance as well as their economic impacts on building HVAC costs have not been investigated. Roof calculator models currently do not account for rooftop modifications such as PV arrays. In this study, we report extensive measurements of a building containing a flush mount and a tilted solar PV array as well as exposed reference roof. Exterior air and surface temperature, wind speed, and solar radiation were measured and thermal infrared (TIR) images of the interior ceiling were taken. We found that in daytime the ceiling surface temperature under the PV arrays was significantly cooler than under the exposed roof. The maximum difference of 2.5 C was observed at around 1800h, close to typical time of peak energy demand. Conversely at night, the ceiling temperature under the PV arrays was warmer, especially for the array mounted flat onto the roof. A one dimensional conductive heat flux model was used to calculate the temperature profile through the roof. The heat flux into the bottom layer was used as an estimate of the heat flux into the building. The mean daytime heat flux (1200-2000 PST) under the exposed roof in the model was 14.0 Watts per square meter larger than

  19. Cool Roofs to Save Money and Delay Global Warming

    Science.gov (United States)

    Rosenfeld, Arthur

    2006-04-01

    White roofs, and now cool-colored roofs, with a high reflectivity or `albedo' have a long history (best known around the Mediterranean) of keeping buildings and cities cool. In modern times, cool roofs have been shown to reduce air conditioning (a-c) demand and slow the formation of ozone (smog). Studies establishing a typical 10% reduction in a-c demand and electricity savings due to white roofs in California (CA) resulted in the 2005 CA new building energy efficiency standard prescribing that low-slope roofs be white, but exempting sloping roofs for aesthetic reasons. The advent (thanks to physicists' efforts) of inexpensive colored pigments with high albedo has led to 2008 CA standards requiring that even sloping roofs be cool. Here, I show that cooling the planet by reducing urban albedo through white and other cool roofs is a direct effect, much larger and immediate than the 2nd-order cooling from reduced CO2 from reduced a-c use. I then investigate widespread deployment of cool roof in major tropical and temperate cities, which cover 2% of global land area and have a proportionately higher albedo impact due to lower latitude. Here, cool roofs and cooler pavements can raise urban albedo by 10%. This directly drops the global average temperature by ˜0.05 /deg C. Though small compared to a likely 3 /deg C rise by 2060, an immediate drop of 0.05 /deg C represents a reprieve in global warming of 1 year, and represents avoiding a year's current annual world emissions of CO2, i.e. 25 GT(CO2). At a trading price of 25/tCO2, this is worth ˜625B. Cooling the planet also could save annually hundreds of billions on a-c electric bills. Finally I suggest policies to increase cool roof deployment, for example, developed world Kyoto signatories could use its CDM (Clean Development Mechanism) for cool roof programs in developing countries.

  20. Automatic Generation of 3D Building Models with Multiple Roofs

    Institute of Scientific and Technical Information of China (English)

    Kenichi Sugihara; Yoshitugu Hayashi

    2008-01-01

    Based on building footprints (building polygons) on digital maps, we are proposing the GIS and CG integrated system that automatically generates 3D building models with multiple roofs. Most building polygons' edges meet at right angles (orthogonal polygon). The integrated system partitions orthogonal building polygons into a set of rectangles and places rectangular roofs and box-shaped building bodies on these rectangles. In order to partition an orthogonal polygon, we proposed a useful polygon expression in deciding from which vertex a dividing line is drawn. In this paper, we propose a new scheme for partitioning building polygons and show the process of creating 3D roof models.

  1. Can green roof act as a sink for contaminants? A methodological study to evaluate runoff quality from green roofs.

    Science.gov (United States)

    Vijayaraghavan, K; Joshi, Umid Man

    2014-11-01

    The present study examines whether green roofs act as a sink or source of contaminants based on various physico-chemical parameters (pH, conductivity and total dissolved solids) and metals (Na, K, Ca, Mg, Al, Fe, Cr, Cu, Ni, Zn, Cd and Pb). The performance of green roof substrate prepared using perlite, vermiculite, sand, crushed brick, and coco-peat, was compared with local garden soil based on improvement of runoff quality. Portulaca grandiflora was used as green roof vegetation. Four different green roof configurations, with vegetated and non-vegetated systems, were examined for several artificial rain events (un-spiked and metal-spiked). In general, the vegetated green roof assemblies generated better-quality runoff with less conductivity and total metal ion concentration compared to un-vegetated assemblies. Of the different green roof configurations examined, P. grandiflora planted on green roof substrate acted as sink for various metals and showed the potential to generate better runoff.

  2. Roof structure theory and support resistance determination of longwall face in shallow seam

    Institute of Scientific and Technical Information of China (English)

    HUANG Qing-xiang(黄庆享)

    2003-01-01

    This paper presents the structure models founded in shallow seam, the roof asymmetry arch with three articulations in roof first weighting and the step voussoir beam in roof periodic weighting. These structure models are differ from classic theory, it establishes the new roof control theory of instability structure roof, especially in shallow seam. Based on the new roof structure theory, the support working state of "given sliding load" is put forward, and the factor of load transmitting is introduced to determine the load on roof structure. Therefore, the proper and accurate calculating methods of support resistance are established. Based on this, the dynamic structure theory in shallow seam could be predicted.

  3. 拱顶储油罐的机械清洗%Mechanical cleaning of dome-roof tank

    Institute of Scientific and Technical Information of China (English)

    宋龙进; 顾德哲; 孙成德

    2012-01-01

    This paper discusses the application of mechanical cleaning technology and its necessity in dome-roof oil tank. In consideration of the differences existed in mechanical cleaning technology for dome-roof tank and floating-roof tank, the installation method of jet should be different. For the dome-roof tank, the jet shall be installed on the top of the tank, and installation of it includes two types, one is made with the existing hole on the tank-top, and another is made with tapping on the tank-top, and if the jet installation location and jet quantity cannot satisfy the requirements of the cleaning operation, the jet can be installed on the tank wall near manholes. In the paper, the technical preparation procedure before tapping including the manufacture method of fixing support of jet, prefabrication of tapping adapter and technical key points of bonding with tank roof, installation of tapping machine, and safety measures of tapping operation, and other tapping operation technology is given, and the cautions in mechanical cleaning operation are provided.%阐述了机械清洗技术在拱顶储油罐中的应用现状,基于拱顶罐与浮顶罐机械清洗技术的差异,分析了两者在喷嘴安装方式上的区别.拱顶罐清洗喷嘴安装在罐顶部,包括利用现有的罐顶管口和在罐顶重新开孔两种形式;当罐顶安装的喷嘴位置或数量达不到清洗作业要求时,亦可在罐壁人孔部位安装喷嘴.此外,介绍了罐顶开孔前的技术准备、储罐清洗喷嘴固定支座的制作方法、罐顶开孔短接管的预制及其与罐顶板的粘接技术要领、开孔机的安装和开孔作业安全措施等拱顶罐罐顶开孔作业技术,总结了拱顶罐机械清洗作业程序及清洗施工中的安全注意事项.

  4. Shipwreck! The floating inferno: Yarmouth Castle

    National Research Council Canada - National Science Library

    Armstrong, J; Ramer, H

    1998-01-01

    The Yarmouth Castle embarked on an overnight trip from Miami to the Bahamas every weekend - until November, 1965, when this midnight cruise to paradise became a floating inferno that left 87 passengers dead...

  5. Physical model tests for floating wind turbines

    DEFF Research Database (Denmark)

    Bredmose, Henrik; Mikkelsen, Robert Flemming; Borg, Michael

    Floating offshore wind turbines are relevant at sites where the depth is too large for the installation of a bottom fixed substructure. While 3200 bottom fixed offshore turbines has been installed in Europe (EWEA 2016), only a handful of floating wind turbines exist worldwide and it is still...... an open question which floater concept is the most economically feasible. The design of the floaters for the floating turbines relies heavily on numerical modelling. While several coupled models exist, data sets for their validation are scarce. Validation, however, is important since the turbine behaviour...... is complex due to the combined actions of aero- and hydrodynamic loads, mooring loads and blade pitch control. The present talk outlines two recent test campaigns with a floating wind turbine in waves and wind. Two floater were tested, a compact TLP floater designed at DTU (Bredmose et al 2015, Pegalajar...

  6. The floating city as an ecosystem

    NARCIS (Netherlands)

    Van Uffelen, C., Rentmeester, S.

    2015-01-01

    Floating construction: several municipalities in the Netherlands are working with it on a small scale. TU Delft alumnus Rutger de Graaf of the YesDelft company DeltaSync would like to speed things up with his Blue Revolution.

  7. Video-OCS Floating Wind Farm Site

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data release contains digital video files from the USGS field activity 2014-607-FA, a survey of the Oregon Outer Continental Shelf (OCS) Floating Wind Farm Site...

  8. Genetics Home Reference: Floating-Harbor syndrome

    Science.gov (United States)

    ... child may have bones more typical of a child of 2. However, bone age is usually normal by age 6 to 12. Delay in speech development (expressive language delay) may be severe in Floating-Harbor syndrome , ...

  9. A Method to Solve the Limitations in Drawing External Rays of the Mandelbrot Set

    Directory of Open Access Journals (Sweden)

    M. Romera

    2013-01-01

    Full Text Available The external rays of the Mandelbrot set are a valuable graphic tool in order to study this set. They are drawn using computer programs starting from the Böttcher coordinate. However, the drawing of an external ray cannot be completed because it reaches a point from which the drawing tool cannot continue drawing. This point is influenced by the resolution of the standard for floating-point computation used by the drawing program. The IEEE 754 Standard for Floating-Point Arithmetic is the most widely used standard for floating-point computation, and we analyze the possibilities of the quadruple 128 bits format of the current IEEE 754-2008 Standard in order to draw external rays. When the drawing is not possible, due to a lack of resolution of this standard, we introduce a method to draw external rays based on the escape lines and Bézier curves.

  10. Genetic Algorithms, Floating Point Numbers and Applications

    Science.gov (United States)

    Hardy, Yorick; Steeb, Willi-Hans; Stoop, Ruedi

    The core in most genetic algorithms is the bitwise manipulations of bit strings. We show that one can directly manipulate the bits in floating point numbers. This means the main bitwise operations in genetic algorithm mutations and crossings are directly done inside the floating point number. Thus the interval under consideration does not need to be known in advance. For applications, we consider the roots of polynomials and finding solutions of linear equations.

  11. Verified Compilation of Floating-Point Computations

    OpenAIRE

    Boldo, Sylvie; Jourdan, Jacques-Henri; Leroy, Xavier; Melquiond, Guillaume

    2015-01-01

    International audience; Floating-point arithmetic is known to be tricky: roundings, formats, exceptional values. The IEEE-754 standard was a push towards straightening the field and made formal reasoning about floating-point computations easier and flourishing. Unfortunately, this is not sufficient to guarantee the final result of a program, as several other actors are involved: programming language, compiler, architecture. The CompCert formally-verified compiler provides a solution to this p...

  12. Travel Time Estimation Using Floating Car Data

    CERN Document Server

    Sevlian, Raffi

    2010-01-01

    This report explores the use of machine learning techniques to accurately predict travel times in city streets and highways using floating car data (location information of user vehicles on a road network). The aim of this report is twofold, first we present a general architecture of solving this problem, then present and evaluate few techniques on real floating car data gathered over a month on a 5 Km highway in New Delhi.

  13. Capillary floating and the billiard ball problem

    OpenAIRE

    Gutkin, Eugene

    2010-01-01

    We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cyli...

  14. Floating wetlands for urban stormwater treatment

    OpenAIRE

    Wang, Chih-Yu

    2013-01-01

    A floating treatment wetland (FTW) is an ecological approach which seeks to reduce point and nonpoint source pollution by installing substrate rooted plants grown on floating mats in open waters. While relatively novel, FTW use is increasing. A review of literature identified several research gaps, including: (1) assessments of the treatment performance of FTWs; (2) evaluations of FTWs in the U.S., particularly within wet ponds that receive urban runoff; and (3) plant temporal nutrient distri...

  15. Technical considerations in green roof retrofit for stormwater attenuation in the central business district

    OpenAIRE

    Wilkinson, S.; Lamond, J.; Proverbs, D.; Sharman, L.; Heller, A; Manion, J.

    2015-01-01

    Purpose: The key aspects that built environment professionals need to consider when evaluating roofs for the purpose of green roof retrofit and also when assessing green roofs for technical due diligence purposes are outlined. Although green or sod roofs have been built over many centuries, contemporary roofs adopt new approaches and technologies. The paper aims to discuss these issues. \\ud \\ud Design/methodology/approach: A mixed methods design based on a systematic review of relevant litera...

  16. The Feasibility of Installing and Monitoring an Extensive Green Roof at Purdue University

    OpenAIRE

    2007-01-01

    The Boiler Green Initiative (BGI) is a student-run organization working to improve environmental sustainability at the Purdue University West Lafayette campus. A main goal of BGI's is to install a green roof on an existing building on campus that is being replaced. We discuss the benefits of green roofs, the feasibility of having one installed on the Armory's roof and the various monitoring options we have researched. Flat roofs are especially amenable to the green roof system, so a building ...

  17. Modeling a Hydrologically Optimal Green Roof Media Mixture

    Science.gov (United States)

    Background/Questions/MethodsA key environmental concern in managing urban ecosystems is controlling stormwater runoff to ameliorate pollution problems and sewage overflows. Vegetated green roofs have become an important green infrastructure tool to collect, store, and gradually r...

  18. Roof Isolation System - A Vibration Absorber for Buildings

    Institute of Scientific and Technical Information of China (English)

    田志昌; 钱稼茹

    2001-01-01

    A roof isolation system is proposed to reduce the dynamic response of buildings to earthquake excitations. In the system, frictional materials are inserted between the roof slab and the beams that support the slab. The roof slab and the beams are connected by springs. The optimum stiffness of the system is determined to minimize the seismic response of the buildings. A comparative study of the responses of an eight-story frame structure with and without the proposed system to ground motions was carried out to assess the system effectiveness. The study showed that the system energy dissipation capacity is nonlinear. The effectiveness of the system is related to the frequency and the acceleration of the ground motion. The system reduces the maximum lateral displacement response and the maximum inter-story drift response of the building by as much as 45% except for the roof.

  19. Experimental measurements and numerical modelling of a green roof

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, Renato M.; Castellotti, Francesco; Busato, Filippo [Padova Univ., Dept. of Management and Engineering, Vicenza (Italy)

    2005-12-15

    Green roof utilisation has been known since ancient times both in hot and cold climates. Nowadays, it has been reconsidered at issue of energy saving and pollution reduction. In this paper, some measurement sessions on a green roof installed by the Vicenza Hospital are described. A data logging system with temperature, humidity, rainfall, radiation, etc. sensors surveyed both the parameters related to the green roof and to the rooms underneath. The aim is to evaluate the passive cooling, stressing the evapotranspiration role in summer time. Furthermore, the enhanced insulating properties have been tested during winter time. A predictive numerical model has been developed in a building simulation software (TRNSYS) to calculate thermal and energy performances of a building with a green roof, varying the meteorological dataset for a specific geographic zone. (Author)

  20. Variability of Rain Water Quality due to Roof Characteristics | Utsev ...

    African Journals Online (AJOL)

    Variability of Rain Water Quality due to Roof Characteristics. ... is receiving increased attention worldwide as an alternative source of drinking water. ... as grey water for domestic purposes but requires treatment to be used as drinking water.

  1. MODELING OF STORM WATER RUNOFF FROM GREEN ROOFS

    Directory of Open Access Journals (Sweden)

    Ewa Burszta-Adamiak

    2014-10-01

    Full Text Available Apart from direct measurements, modelling of runoff from green roofs is valuable source of information about effectiveness of this type of structure from hydrological point of view. Among different type of models, the most frequently used are numerical models. They allow to assess the impact of green roofs on decrease and attenuation of runoff, reduction of peak runoff and value of water retention. This paper presents preliminary results of research on computing the rate of runoff from green roofs using GARDENIA model. The analysis has been carried out for selected rainfall events registered during measuring campaign on pilot-scale green roofs. Obtained results are promising and show good fit between observed and simulated runoff.

  2. High Alumina Refractory Bricks for Electric Arc Furnace Roofs

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 1 Scope This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.

  3. Green roofs: A possible best management practice for enhancing ...

    African Journals Online (AJOL)

    ... roofs: A possible best management practice for enhancing the environmental quality ... erodes the natural ability of the locale to perform its ecosystem services. ... structural components, formulation of guidelines for the industry, government ...

  4. Home advantage in retractable-roof baseball stadia.

    Science.gov (United States)

    Romanowich, Paul

    2012-10-01

    This study examined whether the home advantage varies for open-air, domed, or retractable-roof baseball stadia, and whether having the roof open or closed affects the home advantage in retractable-roof baseball stadia. Data from Major League Baseball (MLB) games played between 2001 and 2009 were analyzed for whether or not the presence of a home-advantage was dependent on the type of home stadium used. Home advantage was robust for all three types of stadia. A significant effect of stadium type on home advantage was found, with a greater home advantage for teams playing home games in domed stadia relative to open-air stadia, replicating a previous study. There was a greater home advantage for teams playing home games in domed stadia relative to retractable-roof stadia. No other differences in the home advantage were found; results are discussed in terms of familiarity with the facility.

  5. Diaphragm Effect of Steel Space Roof Systems in Hall Structures

    Directory of Open Access Journals (Sweden)

    Mehmet FENKLİ

    2015-09-01

    Full Text Available Hall structures have been used widely for different purposes. They have are reinforced concrete frames and shear wall with steel space roof systems. Earthquake response of hall structures is different from building type structures. One of the most critical nodes is diaphragm effect of steel space roof on earthquake response of hall structures. Diaphragm effect is depending on lateral stiffness capacity of steel space roof system. Lateral stiffness of steel space roof system is related to modulation geometry, support conditions, selected sections and system geometry. In current paper, three representative models which are commonly used in Turkey were taken in to account for investigation. Results of numerical tests were present comparatively

  6. How EPA's Asbestos Regulations Apply to Roofing Materials

    Science.gov (United States)

    Guidance Manual and letters that clarify the applicability of the asbestos National Emissions Standard for Hazardous Air Pollutants (NESHAP) to the removal of asbestos-containing roofing material including tiles, and piping during demolition

  7. Analysis of mechanism of shock bump due to roof fall

    Institute of Scientific and Technical Information of China (English)

    GU Xin-jian; LI Jian-xiong

    2004-01-01

    According to the characteristics of the shock bump due to roof fall, a simple mechanics model has been established by applying the catastrophic theory and the law of energy conservation. The author suggests that the shock bump may be induced by the sudden energy release in the roof falling after underground mineral extractions, and through the systematic analysis of actual examples on site, the empirical formulae for the roof falling and energy release are derived, which would provide a new way for the study of the origin and mechanism of mine tremor due to fallen-in roof structure. It is of a great importance to enrich the shock bump theory and production safety in mine.

  8. Application of solar roof shallow pool at individual residental buildings

    Directory of Open Access Journals (Sweden)

    Gavrilović Dragan J.

    2011-01-01

    Full Text Available The paper discusses the possibility of applying shallow roof pools of water on the basis of passive solar water capture functioning as thermal batteries and thermal "regulators" in a "hot - cold" mode with individual residential buildings. With this application, the utilization of the existing functionality of the building roof area would improve and open up the possibility of achieving better overall bio-climate individual object. By using this system, a flat roof impassable "terrace" takes on a new, additional energy function, which proves the ability to reduce overall energy consumption of total conventional seasonal heating and cooling consumption of a building. Supporting of this intention, the paper gives a variant solution of an easily prefabricated reinforced concrete roof system of shallow water pool that works on the principle of passive solar energy capture.

  9. Soil-water fluxes modelling in a green roof

    Science.gov (United States)

    Lamera, Carlotta; Rulli, Maria Cristina; Becciu, Gianfranco; Rosso, Renzo

    2014-05-01

    Green roofs differ from a natural environment as they are on top of a building and are not connected to the natural ground; therefore it is critical that soils can drain and retain water simultaneously and that they work even in very shallow systems. The soil or growing medium used for green roofs is specifically engineered to provide the vegetation with nutrients, discharging any excess water into the drainage layer, and releasing stored water back into the substrate. In this way, medium depth and porosity plays an important role in stormwater retention and plant growth in a green roof. Due to the lack of a good understanding about the hydraulic efficiency of each green roof's layer in rainwater management, a detailed analysis of the hydrological dynamics, connected with the green roof technical design is essential in order to obtain a full characterization of the hydrologic behavior of a green roof system and its effects on the urban water cycle components. The purpose of this research is analyzing the soil-water dynamics through the different components of a green roof and modeling these processes though a detailed but clear subsurface hydrology module, based on green roof vertical soil water movement reproduction, in relation to climate forcing, basic technology components and geometric characteristics of green roof systems (thickness of the stratigraphy, soil layers and materials, vegetation typology and density). A multi-layer bucket model has been applied to examine the hydrological response of the green roof system under a temperate maritime climate, by varying the physical and geometric parameters that characterize the different components of the vegetated cover. Following a stage of validation and calibration, results confirm the suitability of the model to describe the hydrologic response of the green roof during the observed rainfall events: the discharge hydrograph profile, volume and timing, predicted by the model, matched experimental measurements

  10. Plant species richness enhances nitrogen retention in green roof plots.

    Science.gov (United States)

    Johnson, Catherine; Schweinhart, Shelbye; Buffam, Ishi

    2016-10-01

    Vegetated (green) roofs have become common in many cities and are projected to continue to increase in coverage, but little is known about the ecological properties of these engineered ecosystems. In this study, we tested the biodiversity-ecosystem function hypothesis using commercially available green roof trays as replicated plots with varying levels of plant species richness (0, 1, 3, or 6 common green roof species per plot, using plants with different functional characteristics). We estimated accumulated plant biomass near the peak of the first full growing season (July 2013) and measured runoff volume after nearly every rain event from September 2012 to September 2013 (33 events) and runoff fluxes of inorganic nutrients ammonium, nitrate, and phosphate from a subset of 10 events. We found that (1) total plant biomass increased with increasing species richness, (2) green roof plots were effective at reducing storm runoff, with vegetation increasing water retention more than soil-like substrate alone, but there was no significant effect of plant species identity or richness on runoff volume, (3) green roof substrate was a significant source of phosphate, regardless of presence/absence of plants, and (4) dissolved inorganic nitrogen (DIN = nitrate + ammonium) runoff fluxes were different among plant species and decreased significantly with increasing plant species richness. The variation in N retention was positively related to variation in plant biomass. Notably, the increased biomass and N retention with species richness in this engineered ecosystem are similar to patterns observed in published studies from grasslands and other well-studied ecosystems. We suggest that more diverse plantings on vegetated roofs may enhance the retention capacity for reactive nitrogen. This is of importance for the sustained health of vegetated roof ecosystems, which over time often experience nitrogen limitation, and is also relevant for water quality in receiving waters

  11. MODELING OF STORM WATER RUNOFF FROM GREEN ROOFS

    OpenAIRE

    Ewa Burszta-Adamiak; Wiesław Fiałkiewicz

    2014-01-01

    Apart from direct measurements, modelling of runoff from green roofs is valuable source of information about effectiveness of this type of structure from hydrological point of view. Among different type of models, the most frequently used are numerical models. They allow to assess the impact of green roofs on decrease and attenuation of runoff, reduction of peak runoff and value of water retention. This paper presents preliminary results of research on computing the rate of runoff from green ...

  12. On the Design of Suspended Roofs with Paraboloidal Surfaces

    Directory of Open Access Journals (Sweden)

    N. Ungureanu

    2006-01-01

    Full Text Available Some considerations concerning the design of the paraboloidal suspended roofs are made. The main geometric aspects are first time presented. For the roofs we propose, as pattern, the equivalent continuum membranes, and the efforts in the cable are determined by using the membrane efforts and their equations. Two examples are analyzed: elliptic paraboloide and hyperbolic paraboloide, with horizontal projection under the form of an ellipse.

  13. Composition and Diversity of Avian Communities Using a New Urban Habitat: Green Roofs

    Science.gov (United States)

    Washburn, Brian E.; Swearingin, Ryan M.; Pullins, Craig K.; Rice, Matthew E.

    2016-06-01

    Green roofs on buildings are becoming popular and represent a new component of the urban landscape. Public benefits of green roof projects include reduced stormwater runoff, improved air quality, reduced urban heat island effects, and aesthetic values. As part of a city-wide plan, several green roofs have been constructed at Chicago's O'Hare International Airport (ORD). Like some other landscaping features, green roofs on or near an airport might attract wildlife and thus increase the risk of bird-aircraft collisions. During 2007-2011, we conducted a series of studies to evaluate wildlife use of newly constructed green roofs and traditional (gravel) roofs on buildings at ORD. These green roofs were 0.04-1.62 ha in area and consisted of primarily stonecrop species for vegetation. A total of 188 birds were observed using roofs during this research. Of the birds using green roofs, 66, 23, and 4 % were Killdeer, European Starlings, and Mourning Doves, respectively. Killdeer nested on green roofs, whereas the other species perched, foraged, or loafed. Birds used green roofs almost exclusively between May and October. Overall, avian use of the green roofs was minimal and similar to that of buildings with traditional roofs. Although green roofs with other vegetation types might offer forage or cover to birds and thus attract potentially hazardous wildlife, the stonecrop-vegetated green roofs in this study did not increase the risk of bird-aircraft collisions.

  14. Composite Sliding Mode Control for a Free-Floating Space Rigid-Flexible Coupling Manipulator System

    OpenAIRE

    Wang Congqing; Wu Pengfei; Zhou Xin; Pei Xiwu

    2013-01-01

    The flexible space manipulator is a highly nonlinear and coupled dynamic system. This paper proposes a novel composite sliding mode control to deal with the vibration suppression and trajectory tracking of a free‐floating space rigid‐flexible coupling manipulator with a rigid payload. First, the dynamic equations of this system are established by using Lagrange and assumed mode methods and in the meantime this dynamic modelling allows consideration of the modelling errors, the external distur...

  15. Detectability of Free Floating Planets in Open Clusters with JWST

    CERN Document Server

    Pacucci, Fabio; D'Onghia, Elena

    2013-01-01

    Recent observations have shown the presence of extra-solar planets in Galactic open stellar clusters, as in the Praesepe (M44). These systems provide a favorable environment for planetary formation due to the high heavy-element content exhibited by the majority of their population. The large stellar density, and corresponding high close-encounter event rate, may induce strong perturbations of planetary orbits with large semimajor axes. Here we present a set of N-body simulations implementing a novel scheme to treat the tidal effects of external stellar perturbers on planetary orbit eccentricity and inclination. By simulating five nearby open clusters we determine the rate of occurrence of bodies extracted from their parent stellar system by quasi-impulsive tidal interactions. We find that the specific free-floating planet production rate (total number of free-floating planets per unit of time, normalized by the total number of stars) is proportional to the stellar density of the cluster, with a constant of pr...

  16. Floating attenuator wave energy device: Wavegen HYDRA project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This report describes research funded by the Department of Trade and Industry (DTI) into the feasibility of developing and constructing a floating attenuator wave energy device known as HYDRA following initial studies by Wavegen. HYDRA is a floating externally tensioned articulated raft wave energy generator based on work by Professor FJM Farley and colleagues during the 1980s. The project's first four work tasks confirmed the theoretical potential of the device but also highlighted significant practical problems in translating that potential into a viable design. It was therefore decided not to proceed further, i.e. not to construct and test a prototype device. The report provides a general description of the device and describes the results of the initial analysis and the first series of model tests. It then discusses device design and component testing and explains the methodology for determining device performance at a particular site and mathematical modelling of a one-third scale device. To help future research and development programmes, the report emphasises the generic problems associated with the development of wave devices.

  17. The gastrocoel roof plate in embryos of different frogs.

    Science.gov (United States)

    Sáenz-Ponce, Natalia; Santillana-Ortiz, Juan-Diego; del Pino, Eugenia M

    2012-02-01

    The morphology of the gastrocoel roof plate and the presence of cilia in this structure were examined in embryos of four species of frogs. Embryos of Ceratophrys stolzmanni (Ceratophryidae) and Engystomops randi (Leiuperidae) develop rapidly, provide comparison for the analysis of gastrocoel roof plate development in the slow-developing embryos of Epipedobates machalilla (Dendrobatidae) and Gastrotheca riobambae (Hemiphractidae). Embryos of the analyzed frogs develop from eggs of different sizes, and display different reproductive and developmental strategies. In particular, dorsal convergence and extension and archenteron elongation begin during gastrulation in embryos of rapidly developing frogs, as in Xenopus laevis. In contrast, cells that involute during gastrulation are stored in the large circumblastoporal collar that develops around the closed blastopore in embryos of slow-developing frogs. Dorsal convergence and extension only start after blastopore closure in slow-developing frog embryos. However, in the neurulae, a gastrocoel roof plate develops, despite the accumulation of superficial mesodermal cells in the circumblastoporal collar. Embryos of all four species develop a ciliated gastrocoel roof plate at the beginning of neurulation. Accordingly, fluid-flow across the gastrocoel roof plate is likely the mechanism of left-right asymmetry patterning in these frogs, as in X. laevis and other vertebrates. A ciliated gastrocoel roof plate, with a likely origin as superficial mesoderm, is conserved in frogs belonging to four different families and with different modes of gastrulation.

  18. A method for the design of longwall gateroad roof support

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, W. [Geowork Engineering, Emerald, Qld. (Australia)

    2009-06-15

    A longwall gateroad roof support design method for roadway development and panel extraction is demonstrated. It is a hybrid numerical and empirical method called gateroad roof support model (GRSM), where specification of roof support comes from charts or equations. GRSM defines suggested roof support densities by linking a rock-mass classification with an index of mining-induced stress, using a large empirical database of Bowen Basin mining experience. Inherent in the development of GRSM is a rock-mass classification scheme applicable to coal measure strata. Coal mine roof rating (CMRR) is an established and robust coal industry standard, while the geological strength index (GSI) may also be used to determine rock-mass geomechanical properties. An elastic three-dimensional numerical model was established to calculate an index of mining induced stress, for both roadway development and longwall retreat. Equations to calculate stress index derived from the numerical modelling have been developed. An industry standard method of quantifying roof support is adopted as a base template (GRSUP). The statistical analyses indicated that an improved quantification of installed support can be gained by simple modifications to the standard formulation of GRSUP. The position of the mathematically determined stable/failed boundary in the design charts can be changed depending on design criteria and specified risk.

  19. Modelling of green roofs' hydrologic performance using EPA's SWMM.

    Science.gov (United States)

    Burszta-Adamiak, E; Mrowiec, M

    2013-01-01

    Green roofs significantly affect the increase in water retention and thus the management of rain water in urban areas. In Poland, as in many other European countries, excess rainwater resulting from snowmelt and heavy rainfall contributes to the development of local flooding in urban areas. Opportunities to reduce surface runoff and reduce flood risks are among the reasons why green roofs are more likely to be used also in this country. However, there are relatively few data on their in situ performance. In this study the storm water performance was simulated for the green roofs experimental plots using the Storm Water Management Model (SWMM) with Low Impact Development (LID) Controls module (version 5.0.022). The model consists of many parameters for a particular layer of green roofs but simulation results were unsatisfactory considering the hydrologic response of the green roofs. For the majority of the tested rain events, the Nash coefficient had negative values. It indicates a weak fit between observed and measured flow-rates. Therefore complexity of the LID module does not affect the increase of its accuracy. Further research at a technical scale is needed to determine the role of the green roof slope, vegetation cover and drying process during the inter-event periods.

  20. Reliability Analysis of a Green Roof Under Different Storm Scenarios

    Science.gov (United States)

    William, R. K.; Stillwell, A. S.

    2015-12-01

    Urban environments continue to face the challenges of localized flooding and decreased water quality brought on by the increasing amount of impervious area in the built environment. Green infrastructure provides an alternative to conventional storm sewer design by using natural processes to filter and store stormwater at its source. However, there are currently few consistent standards available in North America to ensure that installed green infrastructure is performing as expected. This analysis offers a method for characterizing green roof failure using a visual aid commonly used in earthquake engineering: fragility curves. We adapted the concept of the fragility curve based on the efficiency in runoff reduction provided by a green roof compared to a conventional roof under different storm scenarios. We then used the 2D distributed surface water-groundwater coupled model MIKE SHE to model the impact that a real green roof might have on runoff in different storm events. We then employed a multiple regression analysis to generate an algebraic demand model that was input into the Matlab-based reliability analysis model FERUM, which was then used to calculate the probability of failure. The use of reliability analysis as a part of green infrastructure design code can provide insights into green roof weaknesses and areas for improvement. It also supports the design of code that is more resilient than current standards and is easily testable for failure. Finally, the understanding of reliability of a single green roof module under different scenarios can support holistic testing of system reliability.

  1. Green roofs and the LEED green building rating system

    Energy Technology Data Exchange (ETDEWEB)

    Kula, R. [Sustainable Solutions Inc., Wagoner, OK (United States)

    2005-07-01

    The sustainable building industry is becoming increasingly aware of the host of public and private benefits that green roofs can provide in built environments. In dense urban environments, green roofs function to reduce stormwater runoff, urban heat island effects, and particulate matter (PM) pollution. The emerging green roof industry is now poised to support the efforts of green building networks in North America. This paper discussed the general benefits of green roofs, and their recognition within the Leadership in Energy and Environmental Design (LEED) Green Building Rating System. A case study of Mountain Equipment Co-op's Winnipeg site was presented. The building's green roof was directly responsible for earning 5 credits and contributing to the achievement of an additional 2 credits under the LEEDS certification process. Credits were earned for reduced site disturbance; landscape design to reduce heat islands; and water efficiency. The green roof at the site provided the vast majority of the building's cooling needs through an evaporative cooling trough. A photovoltaic pump was used to feed the building's irrigation system, as well as to pump ground water through cooling valances. It was concluded that the rise of sustainable building practices and the LEED Green Building Rating System will revolutionize the way new buildings are constructed.

  2. Proposed Measures to Protect Temporary Roofs from Unwanted Heat Gains

    Directory of Open Access Journals (Sweden)

    Omar S. Asfour

    2017-06-01

    Full Text Available This study focuses on the uncompleted multi-storey residential buildings located in hot climates. This construction pattern is common in the case of incremental housing, where additional floors are added to the building as housing needs grow. Top roofs in these buildings are usually left without thermal insulation until the rest of upper floors are erected. This causes higher thermal discomfort in the top flats compared to the lower ones. Thus, the aim of this study is to investigate thermal effect of some proposed temporary measures that are intended to protect these roofs from unwanted heat gains until the rest of storeys are constructed. This has been carried out using thermal modelling to find out the effect of these measures on the amount of heat transfer through the roof in both summer and winter times. The analysis showed that it is possible to achieve competent thermal protection of the top roof compared to the layered thermal insulation using simple, cost-effective, and reversible measures. Among the examined measures, covering the roof with white foldable sheets and the use of pergolas have been found to be the most effective measures. In both cases, a reduction of 38% in conductive heat transfer through the top roof in summer was observed compared to the unprotected modelling case.

  3. MODELING PORTFOLIO FLOWS FOR THE POST-FLOATING TURKISH ECONOMY

    Directory of Open Access Journals (Sweden)

    CEM SAATÇİOĞLU

    2013-06-01

    Full Text Available In this paper, a structurally identified vector autoregressive (SVAR model is constructed to examine the determinants of the portfolio-based capital flows for the Turkish economy. Our estimation results using data from the post-floating period reveal that the “push” factors based on the external developments for the Turkish economy have a dominant role to explain the behavior of the portfolio flows. Furthermore, the domestic real interest rates as a main “pull” factor are found in a negative dynamic relationship with the portfolio flows and such a finding is attributed to that the dynamic course of the portfolio flows should not be related to the excess return possibilities of the real interest structure, but rather they shold be related to the risk considerations of the economic agents, resulted from the negative fundamentals of the economy associated with high risk premiums.

  4. Fracturing characteristics of main roof strata when mining uphill and downhill and its effect on stability of immediate roof

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Q.; Liu, J.; Zhang, Y. (Shanxi Mining Institute (China))

    1994-04-01

    The main roof strata in uphill and downhill mining of an inclined longwall may be regarded as an elastic plate. When the ratio of longwall and short span is greater than 2, the load is mainly carried by the short span. Based on this, the authors take a unit width of an inclined rock beam in the direction of face advance and a mechanical model for studying initial and periodic weighting of the main roof was established. It shows that the interval of periodic weighting and abutment pressure in uphill mining are less than that of downhill mining and the distribution of abutment pressure in both cases is quite different. Manifestation of ground pressure in uphill mining is more evident than downhill mining. It is proved that when uphill mining is introduced, the immediate roof is less stable and roof failures are frequent due to stress component in the direction of rock strata and to spalling of coal rib. When the direction of stress component is the same as face advance, the immediate roof is more stable and vice versa if the contrary. From the roof control point of view, where conditions are favourable, priority should be given to downhill mining. 4 refs., 11 figs., 1 tab.

  5. External Otitis (Swimmer's Ear)

    Science.gov (United States)

    ... to Pneumococcal Vaccine Additional Content Medical News External Otitis (Swimmer's Ear) By Bradley W. Kesser, MD, Associate ... the Outer Ear Ear Blockages Ear Tumors External Otitis (Swimmer's Ear) Malignant External Otitis Perichondritis External otitis ...

  6. [Free-Floating Intraocular Cysts].

    Science.gov (United States)

    Werner, Jens Ulrich; Lang, Gerhard K; Enders, Christian

    2017-05-03

    Background Free-floating intraocular cysts may be found in the anterior chamber (FZV) and the vitreous (FZG). The first description of a cyst was 150 years ago, and they are considered to be ocular rarities. Materials and Methods The actual knowledge about FZV and FZG is shown on the basis of two exemplary patients. Results and Discussion Patient 1 had a FZV as an incidental finding which had a smooth surface, a slight pigmentation and was translucent. The ultrasound biomicroscopy revealed an echo-free interior space. Without the patient's discomfort and missing treatment indication, a watch-and-wait strategy was chosen. Cysts of the iris can be classified as primary and secondary cysts. Primary cysts of the iris can arise from the stroma as the pigment epithelium wherein it is believed that FZV descend from the pigment epithelium. Secondary cysts and FZV can be generated by tumors, inflammation, epithelial ingrowth, the use of eye-drops or intraocular foreign bodies. Patient 2 showed marked myopic fundus changes and an FZG with a yellowish-greenish surface; the transparency was reduced and the surface was not pigmented. The ultrasound examination also revealed an echo-free interior space. Clinical controls were advised. Congenital and acquired causes are discussed for the formation of FZG. FZG could originate from the pigment epithelium of the iris, but there are conflicting study results. Trauma, inflammation and chorioretinal diseases are considered as a reason for acquired causes of FZG. The genesis, especially of FZG, is still unclear. For the treatment of patients with FZV and FZG, it is important to know the potential causes to be able to make a therapeutic decision. High quality photographic and sonographic documentation is needed in the watch-and-wait strategy. Georg Thieme Verlag KG Stuttgart · New York.

  7. Temperature reduction in attic and ceiling via insulation of several passive roof designs

    Energy Technology Data Exchange (ETDEWEB)

    Ong, K.S., E-mail: Ong.Kok.Seng@eng.monash.edu.m [Monash University Sunway Campus, Jalan Lagoon Selatan, 46150 Bandar Sunway (Malaysia)

    2011-06-15

    Research highlights: {yields} Six passive roof designs were tested simultaneously outdoors. {yields} Roof, attic and ceiling temperatures were determined. {yields} Solar collector roof design provided the coolest attic and ceiling. {yields} Placing insulation under roof is preferred to above ceiling. -- Abstract: High ambient temperatures coupled with high humidity lead to uncomfortable conditions that are non-conducive for human comfort and productivity. Heat transmission through the roof could be reduced by providing insulation in the attic under the roof or above the ceiling. A roof solar collector could provide both ventilation and cooling in the attic. Several laboratory sized units of passive roof designs were constructed and tested side-by-side under outdoor conditions to obtain temperature data of the roof, attic and ceiling in order to compare their performances.

  8. Inclusion of cool roofs in nonresidential Title 24 prescriptive requirements

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem; Konopacki, Steve; Bretz, Sarah

    2002-12-15

    Roofs that have high solar reflectance (high ability to reflect sunlight) and high thermal emittance (high ability to radiate heat) tend to stay cool in the sun. The same is true of low-emittance roofs with exceptionally high solar reflectance. Substituting a cool roof for a noncool roof tends to decrease cooling electricity use, cooling power demand, and cooling-equipment capacity requirements, while slightly increasing heating energy consumption. Cool roofs can also lower the ambient air temperature in summer, slowing ozone formation and increasing human comfort. DOE-2.1E building energy simulations indicate that use of a cool roofing material on a prototypical California nonresidential building with a low-sloped roof yields average annual cooling energy savings of approximately 300 kWh/1000 ft2 [3.2 kWh/m2], average annual natural gas deficits of 4.9 therm/1000 ft2 [5.6 MJ/m2], average source energy savings of 2.6 MBTU/1000 ft2 [30 MJ/m2], and average peak power demand savings of 0. 19 kW/1000 ft2 [2.1 W/m2]. The 15-year net present value (NPV) of energy savings averages $450/1000 ft2 [$4.90/m2] with time dependent valuation (TDV), and $370/1000 ft2 [$4.00/m2] without TDV. When cost savings from downsizing cooling equipment are included, the average total savings (15-year NPV + equipment savings) rises to $550/1000 ft2 [$5.90/m2] with TDV, and to $470/1000 ft2 [$5.00/m2] without TDV. Total savings range from 0.18 to 0.77 $/ft2 [1.90 to 8.30 $/m2] with TDV, and from 0.16 to 0.66 $/ft2 [1.70 to 7.10 $/m2] without TDV, across California's 16 climate zones. The typical cost premium for a cool roof is 0.00 to 0.20 $/ft2 [0.00 to 2.20 $/m2]. Cool roofs with premiums up to $0.20/ft2 [$2.20/m2] are expected to be cost effective in climate zones 2 through 16; those with premiums not exceeding $0.18/ft2 [$1.90/m2] are expected to be also cost effective in climate zone 1. Hence, this study recommends that the year-2005 California building energy efficiency code (Title

  9. Manipulating soil microbial communities in extensive green roof substrates.

    Science.gov (United States)

    Molineux, Chloe J; Connop, Stuart P; Gange, Alan C

    2014-09-15

    There has been very little investigation into the soil microbial community on green roofs, yet this below ground habitat is vital for ecosystem functioning. Green roofs are often harsh environments that would greatly benefit from having a healthy microbial system, allowing efficient nutrient cycling and a degree of drought tolerance in dry summer months. To test if green roof microbial communities could be manipulated, we added mycorrhizal fungi and a microbial mixture ('compost tea') to green roof rootzones, composed mainly of crushed brick or crushed concrete. The study revealed that growing media type and depth play a vital role in the microbial ecology of green roofs. There are complex relationships between depth and type of substrate and the biomass of different microbial groups, with no clear pattern being observed. Following the addition of inoculants, bacterial groups tended to increase in biomass in shallower substrates, whereas fungal biomass change was dependent on depth and type of substrate. Increased fungal biomass was found in shallow plots containing more crushed concrete and deeper plots containing more crushed brick where compost tea (a live mixture of beneficial bacteria) was added, perhaps due to the presence of helper bacteria for arbuscular mycorrhizal fungi (AMF). Often there was not an additive affect of the microbial inoculations but instead an antagonistic interaction between the added AM fungi and the compost tea. This suggests that some species of microbes may not be compatible with others, as competition for limited resources occurs within the various substrates. The overall results suggest that microbial inoculations of green roof habitats are sustainable. They need only be done once for increased biomass to be found in subsequent years, indicating that this is a novel and viable method of enhancing roof community composition.

  10. Developing resilient green roofs in a dry climate.

    Science.gov (United States)

    Razzaghmanesh, M; Beecham, S; Brien, C J

    2014-08-15

    Living roofs are an emerging green infrastructure technology that can potentially be used to ameliorate both climate change and urban heat island effects. There is not much information regarding the design of green roofs for dry climates and so the aim of this study was to develop low maintenance and unfertilized green roofs for a dry climate. This paper describes the effects of four important elements of green roofs namely slope, depth, growing media and plant species and their possible interactions in terms of plant growth responses in a dry climate. Sixteen medium-scale green roofs were set up and monitored during a one year period. This experiment consisted of twelve vegetated platforms and four non-vegetated platforms as controls. The design for the experiment was a split-split-plot design in which the factors Slope (1° and 25°) and Depth (100mm, 300 mm) were randomized to the platforms (main plots). Root depth and volume, average height of plants, final dry biomass and ground cover, relative growth rate, final dry shoot-root ratio, water use efficiency and leaf succulence were studied during a twelve month period. The results showed little growth of the plants in media type A, whilst the growth was significant in both media types B and C. On average, a 90% survival rate of plants was observed. Also the growth indices indicated that some plants can grow efficiently in the harsh environment created by green roofs in a dry climate. The root growth pattern showed that retained water in the drainage layer is an alternative source of water for plants. It was also shown that stormwater can be used as a source of irrigation water for green roofs during six months of the year at the study site. In summary, mild sloping intensive systems containing media type C and planted with either Chrysocephalum apiculatum or Disphyma crassifolium showed the best performance.

  11. Comparison of Software Models for Energy Savings from Cool Roofs

    Energy Technology Data Exchange (ETDEWEB)

    New, Joshua Ryan [ORNL; Miller, William A [ORNL; Huang, Yu (Joe) [White Box Technologies; Levinson, Ronnen [Lawrence Berkeley National Laboratory (LBNL)

    2014-01-01

    A web-based Roof Savings Calculator (RSC) has been deployed for the United States Department of Energy as an industry-consensus tool to help building owners, manufacturers, distributors, contractors and researchers easily run complex roof and attic simulations. This tool employs modern web technologies, usability design, and national average defaults as an interface to annual simulations of hour-by-hour, whole-building performance using the world-class simulation tools DOE-2.1E and AtticSim in order to provide estimated annual energy and cost savings. In addition to cool reflective roofs, RSC simulates multiple roof and attic configurations including different roof slopes, above sheathing ventilation, radiant barriers, low-emittance roof surfaces, duct location, duct leakage rates, multiple substrate types, and insulation levels. A base case and energy-efficient alternative can be compared side-by-side to estimate monthly energy. RSC was benchmarked against field data from demonstration homes in Ft. Irwin, California; while cooling savings were similar, heating penalty varied significantly across different simulation engines. RSC results reduce cool roofing cost-effectiveness thus mitigating expected economic incentives for this countermeasure to the urban heat island effect. This paper consolidates comparison of RSC s projected energy savings to other simulation engines including DOE-2.1E, AtticSim, Micropas, and EnergyPlus, and presents preliminary analyses. RSC s algorithms for capturing radiant heat transfer and duct interaction in the attic assembly are considered major contributing factors to increased cooling savings and heating penalties. Comparison to previous simulation-based studies, analysis on the force multiplier of RSC cooling savings and heating penalties, the role of radiative heat exchange in an attic assembly, and changes made for increased accuracy of the duct model are included.

  12. Evaluation of solar energy on the roofs of livestock houses

    Directory of Open Access Journals (Sweden)

    Paolo Liberati

    2013-03-01

    Full Text Available There is a great potential for production of thermal and electrical energy by means of solar collectors on farms. To assess in advance the performance of the alternative plant solutions, a computational model for the determination of solar energy absorbed by surfaces with different exposures as a function of latitude, day, orientation and inclination has been created. Its application to roofs of buildings typically used for animal housing is presented; these were mono-pitch, gabled, and shed type roofs. For each building, the annual energy absorption per unit of floor area is calculated by varying orientation and slope of the pitches. For roof surfaces exposed only in one direction (mono-pitch or shed, the orientation is shown to be a dominant factor with respect to the slope in determining the annual energy uptake. The maximum uptake is obtained with exposure to the south and is greater the higher the slope (up to 67.5%. For gabled roofs, the total uptake is negatively affected by the worse exposed pitch and does not vary significantly, for a given slope, with orientation (up to 2.8%. The maximum gain is obtained with the optimal building azimuth (0° and the highest slope. The shed type, since it is affected by the shade induced by the upper pitch over the lower, cannot reach the level of a mono-pitch roof: -1.5% with a slope of 10% and -21% with a slope of 67.5% with the optimal building azimuth of 90°. However, its performance is slightly higher than the corresponding gabled roof (+2.5%, therefore, it could be a convenient alternative if optimally oriented and, above all, if the collectors are installed on the predominantly sunny part of the roof.

  13. Dynamically Reconfigurable Processor for Floating Point Arithmetic

    Directory of Open Access Journals (Sweden)

    S. Anbumani,

    2014-01-01

    Full Text Available Recently, development of embedded processors is toward miniaturization and energy saving for ecology. On the other hand, high performance arithmetic circuits are required in a lot of application in science and technology. Dynamically reconfigurable processors have been developed to meet these requests. They can change circuit configuration according to instructions in program instantly during operations.This paper describes, a dynamically reconfigurable circuit for floating-point arithmetic is proposed. The arithmetic circuit consists of two single precision floating-point arithmetic circuits. It performs double precision floating-point arithmetic by reconfiguration. Dynamic reconfiguration changes circuit construction at one clock cycle during operation without stopping circuits. It enables reconfiguration of circuits in a few nano seconds. The proposed circuit is reconfigured in two modes. In first mode it performs one double precision floating-point arithmetic or else the circuit will perform two parallel operations of single precision floating-point arithmetic. The new system design reduces implementation area by reconfiguring common parts of each operation. It also increases the processing speed with a very little number of clocks.

  14. On the dynamics of floating structures

    CERN Document Server

    Lannes, David

    2016-01-01

    This paper addresses the floating body problem which consists in studying the interaction of surface water waves with a floating body. We propose a new formulation of the water waves problem that can easily be generalized in order to take into account the presence of a floating body. The resulting equations have a compressible-incompressible structure in which the interior pressure exerted by the fluid on the floating body is a Lagrange multiplier that can be determined through the resolution of a $d$-dimensional elliptic equation, where $d$ is the horizontal dimension. In the case where the object is freely floating, we decompose the hydrodynamic force and torque exerted by the fluid on the solid in order to exhibit an added mass effect; in the one dimensional case $d=1$, the computations can be carried out explicitly. We also show that this approach in which the interior pressure appears as a Lagrange multiplier can be implemented on reduced asymptotic models such as the nonlinear shallow water equations an...

  15. Formulation and optimization of carbamazepine floating tablets

    Directory of Open Access Journals (Sweden)

    Patel D

    2007-01-01

    Full Text Available Floating tablets of carbamazepine were developed using melt granulation technique. Bees wax was used as a hydrophobic meltable material. Hydroxypropylmethylcellulose, sodium bicarbonate and ethyl cellulose were used as matrixing agent, gas-generating agent and floating enhancer, respectively. The tablets were evaluated for in vitro buoyancy and dissolution studies. A simplex lattice design was applied to investigate the combined effect of 3 formulation variables i.e. amount of hydroxypropyl methylcellulose ( X 1 , ethyl cellulose ( X 2 and sodium bicarbonate ( X 3 . The floating lag time (F lag , time required for 50% (t 50 and 80% drug dissolution (t 80 were taken as responses. Results of multiple regression analysis indicated that, low level of X 1 and X 2 , and high level of X 3 should be used to manufacture the tablet formulation with desired in vitro floating time and dissolution. Formulations developed using simplex lattice design were fitted to various kinetic models for drug release. Formulation S3 was selected as a promising formulation and was found stable at 40 o and 75% relative humidity for 3 months. Present study demonstrates the use of simplex lattice design in the development of floating tablets with minimum experimentation.

  16. An Integrative Analysis of an Extensive Green Roof System: A Case Study of the Schleman Green Roof

    Science.gov (United States)

    Hoover, F.; Bowling, L. C.

    2013-12-01

    In urban environments where populations continue to rise, the need for affective stormwater management and runoff control methods is ever prevalent. Increased population growth and city expansion means greater impervious surfaces and higher rates of stormwater runoff. In well-established cities, this proves particularly difficult due to a constraining built environment and limited pervious spaces, even in cities as small as 40,000 residents. Work to reduce runoff in combined sewer systems (CSS) and municipal separated storm sewer systems (MS4) by use of best-management practices is one route currently under investigation. The Purdue University campus is making efforts to reduce their impact on the West Lafayette CSS and MS4. Green roofs are one management practice being used for runoff mitigation. Specifically, Schleman Hall, an administrative student affairs building, has a small green roof located on the second floor installed in 2008. In cooperation with Purdue Physical Facilities, monitoring and analysis for the Schleman extensive green roof at Purdue University was performed from June 2012 to December 2012. The objective was to determine the stormwater retention, output water quality and net present value for the 165 m2 roof. The results from the water balance analysis revealed retention rates on average of 58% of precipitation per rain event, where retention included soil moisture, evaporation and detention/depression storage. The water quality metrics tested were Nitrate-Nitrite (NO2-NO3), Orthophosphate (PO4), Ammonia-Ammonium ion (NH3-NH4), Sulfate (SO4), total suspended solids (TSS) and pH. The pollutant concentration and load results varied, but the pH levels from precipitation increased in all samples after passing through the substrate. SO4 and PO4 results yielded higher concentrations and loads in the green roof output than the control output and precipitation, while NO2-NO3 and NH3-NH4 yielded concentrations and loads that were reduced by the green

  17. Lightning protection for roof-mounted solar cell using two masts

    Directory of Open Access Journals (Sweden)

    N. Petcharaks

    2013-03-01

    Full Text Available Houses invested in roof-mounted solar cell need protection from direct lightning. This paper presents the application of numerical method in designing the height and location of masts based on protection angle method according to international standard IEC 62305. An isolated external lightning protection system using two isolated masts is designed. The protected zone which is in the volume according to the protection angle method, depends on the protection level, the rolling sphere radius and the height of the masts which must be less than the rolling sphere radius defined in IEC standard. Furthermore, separation distance between the protected house and mast depends on the height of the mast. This paper develops a program using heuristic numerical method to design masts to protect a house with roof-mounted solar cell. Input data such as the house dimensions and the lightning protection class should be provided. This program is tested on houses with different dimensions. The height and location of two masts are obtained. The numerical results show that this program can be used effectively and correctly.

  18. Cool roofs and the influence on the energy consumption under Danish conditions

    DEFF Research Database (Denmark)

    Brandt, Erik; Bunch-Nielsen, Tommy; Juhl, Lasse

    that there are no significant advantages of using white roofing felt instead of dark under Danish conditions in common buildings with active heating and passive cooling. Quite to the contrary it appears that dark roofing felts have significant advantages over white roofing felts. The results are discussed in the paper....... It should be mentioned that white roofing materials might be beneficial for poorly insulated buildings with high internal heat loads. In this case the white roofing might contribute to a reduced cooling. Also buildings with constant cooling demands or cold-storage plants etc. may benefit from white roofing...

  19. A comparative analysis of selected parameters of roofing used in the Polish construction industry

    Directory of Open Access Journals (Sweden)

    Radziszewska-Zielina Elżbieta

    2014-06-01

    Full Text Available Roofing is an important element in the construction of the roof. It is also one of the essential elements of the whole building. The choice of roofing should depend on technical parameters that affect the quality of the materials used and the price. The present paper is a comparative analysis of the properties of five roofing materials selected as examples with respect to twelve parameters. As can be seen from the comparative analysis of the roofing parameters, roofing tile is by far the best material, receiving the highest score in the ranking

  20. Roof heat loss detection using airborne thermal infrared imagery

    Science.gov (United States)

    Kern, K.; Bauer, C.; Sulzer, W.

    2012-12-01

    As part of the Austrian and European attempt to reduce energy consumption and greenhouse gas emissions, thermal rehabilitation and the improvement of the energy efficiency of buildings became an important topic in research as well as in building construction and refurbishment. Today, in-situ thermal infrared measurements are routinely used to determine energy loss through the building envelope. However, in-situ thermal surveys are expensive and time consuming, and in many cases the detection of the amount and location of waste heat leaving building through roofs is not possible with ground-based observations. For some years now, a new generation of high-resolution thermal infrared sensors makes it possible to survey heat-loss through roofs at a high level of detail and accuracy. However, to date, comparable studies have mainly been conducted on buildings with uniform roof covering and provided two-dimensional, qualitative information. This pilot study aims to survey the heat-loss through roofs of the buildings of the University of Graz (Austria) campus by using high-resolution airborne thermal infrared imagery (TABI 1800 - Thermal Airborne Broadband imager). TABI-1800 acquires data in a spectral range from 3.7 - 4.8 micron, a thermal resolution of 0.05 °C and a spatial resolution of 0.6 m. The remote sensing data is calibrated to different roof coverings (e.g. clay shingle, asphalt shingle, tin roof, glass) and combined with a roof surface model to determine the amount of waste heat leaving the building and to identify hot spots. The additional integration of information about the conditions underneath the roofs into the study allows a more detailed analysis of the upward heat flux and is a significant improvement of existing methods. The resulting data set provides useful information to the university facility service for infrastructure maintenance, especially in terms of attic and roof insulation improvements. Beyond that, the project is supposed to raise public

  1. Thermal Performance of Building Roof with Infrared Reflective Coatings

    Institute of Scientific and Technical Information of China (English)

    SHEN Hui; TAN Hong-wei; KATSUO MIKI; LIU Xiao-yu

    2009-01-01

    This paper investigated the applicability and effects of infrared reflective coating on energy con-sumption of factory building in hot summer and warm winter zone. It first resorted to theoretical calculation, which demonstrated the beneficial effects of infrared reflective coating on reducing building energy consumption. Then it analyzed a field measurement done on two identical rooms respectively with ordinary coated roof and in-frared reflective coated roof from November 2006 to October 2007, on a 24h basis. The measured data include exterior and interior roof surface temperature, indoor air temperature, and indoor globe temperature. The relat-ed weather data is from a weather station near the measured area. The continuous measurement has been accom-plished in southern China, and the measured data indicate that roof surface temperature and heat gain are signifi-cantly decreased in summer while slight negative effects in winter are induced by adopting infrared reflective coating. Thus it is simple and applicable to reduce building energy consumption in this area by applying infrared reflective coating. Regress equation between reduced roof thermal property, such as surface temperature and heat gain, and reduction in absorbed solar radiation shows their highly linear relationship. Based on the mea-sured data, it is estimated that the reduced power consumption is 3.45 kWh/m2·month in June.

  2. Empirically Derived Strength of Residential Roof Structures for Solar Installations.

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, Stephen F.; Sanchez, Alfred; Campos, Ivan A.; Gerstle, Walter H.

    2014-12-01

    Engineering certification for the installation of solar photovoltaic (PV) modules on wood roofs is often denied because existing wood roofs do not meet structural design codes. This work is intended to show that many roofs are actually sufficiently strong given the conservatism in codes, documented allowable strengths, roof structure system effects, and beam composite action produced by joist-sheathing interaction. This report provides results from a testing program to provide actual load carrying capacity of residential rooftops. The results reveal that the actual load carrying capacity of structural members and systems tested are significantly stronger than allowable loads provided by the International Residential Code (IRC 2009) and the national structural code found in Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). Engineering analysis of residential rooftops typically ignores the system affects and beam composite action in determining rooftop stresses given a potential PV installation. This extreme conservatism combined with conservatism in codes and published allowable stress values for roof building materials (NDS 2012) lead to the perception that well built homes may not have adequate load bearing capacity to enable a rooftop PV installation. However, based on the test results presented in this report of residential rooftop structural systems, the actual load bearing capacity is several times higher than published values (NDS 2012).

  3. Effect of Composite Action on the Strength of Wood Roofs

    Directory of Open Access Journals (Sweden)

    Ivan A. Campos Varela

    2015-01-01

    Full Text Available Engineering certification for the installation of solar photovoltaic modules on wood roofs is often denied because existing wood roofs do not meet current building codes. Rather than requiring expensive structural retrofits, we desire to show that many roofs are actually sufficiently strong if the effect of composite action produced by joist-sheathing interaction is considered. In a series of laboratory experiments using a limited number of two-by-four wood joists with and without sheathing panels, conventionally sheathed stud-grade joists, surprisingly, exhibited between 18% and 63% higher nominal strength than similar bare joists. To explain this strength increase, a simple model was developed to predict the strengths of the nailed partially composite sections, but the model only justifies a 1.4% to 3.8% increase in bending strength of joists with an allowable bending strength of 1000 psi. More testing is indicated to resolve this discrepancy between laboratory results and analytical modeling results. In addition to elucidating nonlinear partial composite behavior of existing roof systems, this paper shows that, with minor changes in roof framing practices, strength increases of 70% or more are achievable, compared to the strengths of conventionally sheathed joists.

  4. A fuzzy approach to selecting roof supports in longwall mining

    Directory of Open Access Journals (Sweden)

    Yetkin, M. E.

    2016-05-01

    Full Text Available As a decision-making problem, selecting proper machines and equipment plays a key role for mining sites and companies. Many factors affect this decision, and values belonging to these factors can be expressed numerically and/or non-numerically. In order to make the most appropriate decision, engineers must carry out an evaluation process that comprises all criteria that might affect decision-making. To achieve this, multi-criteria decision-making tools are used. As a result of technological developments, coal outputs in longwall mining have risen tremendously over the last decades, and longwall mechanisation has become unavoidable. The significance of powered roof supports in particular increases day- by-day, since the rate of roof support has to be in accordance with the rate of face advance in longwalls. In this study, an integrated fuzzy analytic hierarchy process and fuzzy goal programming model is used to select the most suitable powered roof supports. The procedure is applied to a real-life underground coal mine that is operated using the longwall method. Seven alternative powered roof supports are compared with each other, taking a total of 24 decision criteria under four main topics into account. In conclusion, the most suitable roof supports for the mine under study are determined and recommended to the decision-makers of the system.

  5. The green roof dilemma - discussion of Francis and Lorimer (2011).

    Science.gov (United States)

    Henry, Alexandre; Frascaria-Lacoste, Nathalie

    2012-08-15

    Urban ecosystems are the most complex mosaics of vegetative land cover that can be found. In a recent paper, Francis and Lorimer (2011) evaluated the reconciliation potential of living roofs and walls. For these authors, these two techniques for habitat improvement have strong potential for urban reconciliation ecology. However they have some ecological and societal limitations such as the physical extreme environmental characteristics, the monetary investment and the cultural perceptions of urban nature. We are interested in their results and support their conclusions. However, for a considerable time, green roofs have been designed to provide urban greenery for buildings and the green roof market has only focused on extensive roof at a restricted scale within cities. Thus, we have strong doubts about the relevance of their use as possible integrated elements of the network. Furthermore, without dynamic progress in research and the implementation of well-thought-out policies, what will be the real capital gain from green roofs with respect to land-use complementation in cities? If we agree with Francis and Lorimer (2011) considering that urban reconciliation ecology between nature and citizens is a current major challenge, then "adaptive collaborative management" is a fundamental requirement.

  6. A New Kind of Roof Greening System in China

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    With the wider use of green roofs, new technology and new materials are being applied to the field of building roof greening forbuildings. This paper introduces BRGS (built- up roof greening system), a new type of roof greening system that differs from roofgreening systems currently used in China in that it integrates a main and an auxiliary water storage capacity into the roof greeningsystem. Compared to other systems currently in use, BRGS offers a simpler, quicker, less labor intensive construction process;lighter floor load; and lower long term maintenance requirements and costs. It also makes full use of rainwater and snowmelt,which provides a significant amount of water to plants. This paper also introduces a planting experiment, the results of whichindicate that plants during their early stages of growth tolerate an alkaline environment, and that after a period of time, the pHvalue level of water stored in BRGS approaches 8.3, so we can conclude that BRGS is suitable for construction engineering.

  7. Numerical simulation of flows around long-span flat roof

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-ying; WU Yue; SHEN Shi-zhao

    2005-01-01

    Long-span roof with span larger than height always has a complicated three-dimensional curve. Wind pressure on the roof is often influenced not only by the atmospheric turbulence, but also by the "signature" turbulence provoked in the wind by the structure itself. So it is necessary to study characteristics of flows around the roof. In this paper, three-dimensional numerical simulation of wind-induced pressure has been performed on a long-span flat roof by means of Computational Fluid Dynamics (CFD) software--FLUENT. The flow characteristics are studied by considering some parameters, such as wind direction, span-height ratio, roof pitch, flow characteristics, roughness of terrain. The simulation is based upon the Reynolds-averaged equations, in which Reynolds stress equation model (RSM) and SIMPLE technology (Semi-Implicit Method for Pressure-Linked Equations) have been used. Compared with wind tunnel tests, the computational results have good agreement with the experimental data. It is proved that the results are creditable and the method is feasible.

  8. Retention performance of green roofs in three different climate regions

    Science.gov (United States)

    Sims, Andrew W.; Robinson, Clare E.; Smart, Charles C.; Voogt, James A.; Hay, Geoffrey J.; Lundholm, Jeremey T.; Powers, Brandon; O'Carroll, Denis M.

    2016-11-01

    Green roofs are becoming increasingly popular for moderating stormwater runoff in urban areas. This study investigated the impact different climates have on the retention performance of identical green roofs installed in London Ontario (humid continental), Calgary Alberta (semi-arid, continental), and Halifax Nova Scotia (humid, maritime). Drier climates were found to have greater percent cumulative stormwater retention with Calgary (67%) having significantly better percent retention than both London (48%) and Halifax (34%). However, over the same study period the green roof in London retained the greatest depth of stormwater (598 mm), followed by the green roof in Halifax (471 mm) and then Calgary (411 mm). The impact of climate was largest for medium sized storms where the antecedent moisture condition (AMC) at the beginning of a rainfall event governs retention performance. Importantly AMC was a very good predictor of stormwater retention, with similar retention at all three sites for a given AMC, emphasizing that AMC is a relevant indicator of retention performance in any climate. For large rainfall events (i.e., >45 mm) green roof average retention ranged between 16% and 29% in all cities. Overall, drier climates have superior retention due to lower AMC in the media. However, moderate and wet climates still provide substantial total volume reduction benefits.

  9. 40 CFR 60.111a - Definitions.

    Science.gov (United States)

    2010-07-01

    ... floating roof. (j) Vapor-mounted seal means a foam-filled primary seal mounted continuously around the... 2517, Evaporation Loss from External Floating-Roof Tanks, Second Edition, February 1980 (incorporated... or 94 (incorporated by reference—see § 60.17). (h) Liquid-mounted seal means a foam or liquid-filled...

  10. Block floating point for radar data

    DEFF Research Database (Denmark)

    Christensen, Erik Lintz

    1999-01-01

    Integer, floating point, and block floating point (BFP) data formats are analyzed and compared in order to establish the mathematical tools for selection of an optimal format which fulfils the demands of high resolution radar (SAR) data to large dynamic range and adequate S/N. The analysis takes...... quantization noise and saturation distortion into account and concludes that it is preferred to use small blocks and a (new) modified BFP format applying fractional exponents. Data from the EMISAR radar system are applied to illustrate the merits of the different schemes....

  11. FLOAT2 WP4: Development of Materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Aarup, Bendt

    This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC.......This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC....

  12. Improvements in floating point addition/subtraction operations

    Energy Technology Data Exchange (ETDEWEB)

    Farmwald, P.M.

    1984-02-24

    Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

  13. Floating Inductance and FDNR Using Positive Polarity Current Conveyors

    OpenAIRE

    Pal, K.

    2004-01-01

    A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.

  14. Floating Inductance and FDNR Using Positive Polarity Current Conveyors

    Directory of Open Access Journals (Sweden)

    K. Pal

    2004-01-01

    Full Text Available A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.

  15. Argo Float Data from the APDRC DAPPER Server

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The floats are designed to drift at a fixed pressure (usually 1000 dbar) for 10 days. After this period, the floats move to a profiling pressure (usually between...

  16. Displacement, stress and seismicity in roadway roofs during mining-induced failure

    Energy Technology Data Exchange (ETDEWEB)

    Shen, B.; King, A.; Guo, H. [CSIRO Exploration & Mining, Kenmore, Qld. (Australia)

    2008-07-15

    Roof stability in gateroads is a long-standing issue in many of the underground mines in Australia that use longwall extraction methods, due primarily to a significant increase of vertical stresses ahead of the longwall face. Although numerous studies have been done in the past, the process of roof rock deformation and breakage prior to and during a roof failure in an actual mining environment is still being debated. This paper describes a new integrated roof monitoring system and the results from applying this system in an Australian underground coal mine. The system integrates displacement, stress and seismic monitoring. It has been applied to two roadways in an Australian underground coal mine during two field experiments. The key roof behaviour identified by the integrated monitoring package during the two field monitoring experiments is reported and discussed in this paper. The experiments were conducted in the 'tailgate' roadways that are adjacent to the caved zone, or 'goaf', of the previously mined panels. It was found in the experiments that, prior to roof falls, roof displacement accelerates whereas the horizontal stresses reduce. Seismic activity intensifies before major roof displacement or stress changes are evident, and subsides in the later stage of roof failure when large roof displacement is visible. The seismic resonance frequencies decrease during roof failure development. The field monitoring studies have also identified a number of quantitative and site-specific roof fall precursors potentially useful for roof fall prediction and prevention.

  17. CFD Simulation of Air Flow Over an Object with Gable Roof, Revised with Y+ Approach

    Directory of Open Access Journals (Sweden)

    Králik Juraj

    2016-12-01

    Full Text Available Aim of this contribution is to provide insight view into analysis focused on obtaining external pressure coefficients on isolated two storey low-rise building with 15° elevation gable roof using Computer Fluid Dynamics simulation and these are compared to values that offering Eurocodes. Final Volume Model consisting of polyhedral mesh will be used for analysis with two different turbulence models. Mesh was created with respect to y+ parameter, where desired value was below one which leads us to fine mesh type. Secondary aim of this contribution is to compare performance of selected turbulence models. For this purpose were chosen Detached Eddy Simulation and Large Eddy Simulation which are part of the Scale Resolving Simulation turbulence models.

  18. Requirements of inverted roofs with a drainage layer

    DEFF Research Database (Denmark)

    Leimer, Hans-Peter; Rode, Carsten; Künzel, Hartwig

    2005-01-01

    flowing between the insulation and the waterproofing membrane. It is possible to calculate the extra heat loss of inverted roofs caused by rain water below the heat insulation. The extra heat loss depends on the average rainfall and on which fraction of the rain water that will drain between...... the waterproofing membrane and the thermal insulation. This paper explains the application of the standard for areas of Europe. Furthermore, some constructions are proposed, which have such small extra heat losses caused by rain water that they may be disregarded in the calculation.......This contribution illustrates the application of the standard EN ISO 6946 regarding the heat loss of an inverted roof for different regions of Europe. An addendum to the standard (EN ISO 6946:1996/A1, 2003) introduces a correction to the thermal transmittance of inverted roofs due to rain water...

  19. Plant functional traits predict green roof ecosystem services.

    Science.gov (United States)

    Lundholm, Jeremy; Tran, Stephanie; Gebert, Luke

    2015-02-17

    Plants make important contributions to the services provided by engineered ecosystems such as green roofs. Ecologists use plant species traits as generic predictors of geographical distribution, interactions with other species, and ecosystem functioning, but this approach has been little used to optimize engineered ecosystems. Four plant species traits (height, individual leaf area, specific leaf area, and leaf dry matter content) were evaluated as predictors of ecosystem properties and services in a modular green roof system planted with 21 species. Six indicators of ecosystem services, incorporating thermal, hydrological, water quality, and carbon sequestration functions, were predicted by the four plant traits directly or indirectly via their effects on aggregate ecosystem properties, including canopy density and albedo. Species average height and specific leaf area were the most useful traits, predicting several services via effects on canopy density or growth rate. This study demonstrates that easily measured plant traits can be used to select species to optimize green roof performance across multiple key services.

  20. Validation of salinity data from ARGO floats: Comparison between the older ARGO floats and that of later deployments

    Digital Repository Service at National Institute of Oceanography (India)

    Youn, Y.-H.; Lee, H.; Chang, Y.-S.; Pankajakshan, T.

    Continued observation of ARGO floats or years (about 4 years) makes the conductivity sensor more vulnerable to fouling by marine life and associated drift in salinity measurements. In this paper, we address this issue by making use of floats...

  1. 14 CFR 29.757 - Hull and auxiliary float strength.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and auxiliary float strength. 29.757 Section 29.757 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 29.757 Hull and auxiliary float strength. The hull, and auxiliary floats if used, must withstand...

  2. 14 CFR 25.753 - Main float design.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 25.753 Section 25.753 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design...

  3. Choosing the right green roof media for water quality

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, W.F.; Hathaway, A.M.; Smith, J.T.; Calabria, J. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Biological and Agricultural Engineering

    2006-07-01

    Due to the large concentrations of a variety of contaminants entering streams and rivers, stormwater is a significant contributor to the impairment of North Carolina (NC) waters. Pollutants range from pesticides and nutrients to oils and petroleum products to construction chemicals and sediment which are evident in fish kills, contamination of drinking water supplies, and deterioration of wildlife habitats. One of the major tools to improve storm water quality are stormwater best management practices (BMPs). BMPs include bioretention areas, wet and dry detention ponds, constructed wetlands, and sand filters. One option for urban BMPs is the green roof which uses rooftop square footage that would not otherwise be available on the ground. A research project was conducted that tests two field green roofs in Raleigh and Asheville, NC. In addition, a laboratory test was conducted in 2004 and a plot study of three designer media was conducted in 2005 on the NC State University Campus in Raleigh, NC. The objectives of the research were to examine how different green roof media reduce concentrations of nitrogen and phosphorus, if the leaching rate of nitrogen and phosphorus from soil media of field green roofs decrease with time, and to determine whether green roofs can be used as nutrient reduction BMPs. This paper provided background information on previous green roof stormwater research, discussed each of the sites chosen for the study in detail and presented the field monitoring process and laboratory study methodology. This was followed by a detailed examination of the results. It was concluded that an optimal soil media can be established that balances plant growth with water quality and quantity control. 16 refs., 2 tabs., 8 figs.

  4. Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [Building Science Corporation, Westford, MA (United States); Lstiburek, Joseph W. [Building Science Corporation, Westford, MA (United States)

    2015-09-01

    Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a control vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. The Houston-area roof was an unvented attic insulated with spray-applied fiberglass. Most ridges and hips were built with a diffusion vent detail, capped with vapor permeable roof membrane. In contrast, the diffusion vent roofs had drier conditions at the roof peak in wintertime, but during the summer, RHs and MCs were higher than the unvented roof (albeit in the safe range).

  5. Damage to thermal insulation foams in low-slope roof systems caused by simulated foot traffic

    National Research Council Canada - National Science Library

    Liu, Karen K; Booth, R. J

    1999-01-01

    The results indicated that common.ly used foam plastic roof insulations will be damaged if exposed to foot traffic, and that their protection with fibrous overlay boards as recommended by roofing contractor associations continues...

  6. Extraction of Roof Lines from High-Resolution Images by a Grouping Method

    Science.gov (United States)

    Dal Poz, A. P.; Fernandes, V. J. M.

    2016-06-01

    This paper proposes a method for extracting groups of straight lines that represent roof boundaries and roof ridgelines from highresolution aerial images using corresponding Airborne Laser Scanner (ALS) roof polyhedrons as initial approximations. The proposed method is based on two main steps. First, straight lines that are candidates to represent roof ridgelines and roof boundaries of a building are extracted from the aerial image. Second, a group of straight lines that represent roof boundaries and roof ridgelines of a selected building is obtained through the optimization of a Markov Random Field (MRF)-based energy function using the genetic algorithm optimization method. The formulation of this energy function considers several attributes, such as the proximity of the extracted straight lines to the corresponding projected ALS-derived roof polyhedron and the rectangularity (extracted straight lines that intersect at nearly 90°). Experimental results are presented and discussed in this paper.

  7. Single-Sided Natural Ventilation through a Velux Roof Window

    DEFF Research Database (Denmark)

    Li, Zhigang; Nielsen, Peter Vilhelm; Fransson, J.

    2004-01-01

    This paper investigates the single-sided natural ventilation through a VELUX centre pivot roof window under natural weather conditions. The aim of the investigation is to develop an empirical formulation for air flow rate through a roof window based on CFD and tracer gas decay measurement methods....... CFD can separate buoyancy and wind effects in the calculation of the air flow rate through a window opening, but it is difficult to isolate wind effect from buoyancy forces during measurements. The ?Warren-plot? method can be used to separate and analyse the measured data which are dominated by stack...

  8. Modelling of green roof hydrological performance for urban drainage applications

    Science.gov (United States)

    Locatelli, Luca; Mark, Ole; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten; Bergen Jensen, Marina; Binning, Philip John

    2014-11-01

    Green roofs are being widely implemented for stormwater management and their impact on the urban hydrological cycle can be evaluated by incorporating them into urban drainage models. This paper presents a model of green roof long term and single event hydrological performance. The model includes surface and subsurface storage components representing the overall retention capacity of the green roof which is continuously re-established by evapotranspiration. The runoff from the model is described through a non-linear reservoir approach. The model was calibrated and validated using measurement data from 3 different extensive sedum roofs in Denmark. These data consist of high-resolution measurements of runoff, precipitation and atmospheric variables in the period 2010-2012. The hydrological response of green roofs was quantified based on statistical analysis of the results of a 22-year (1989-2010) continuous simulation with Danish climate data. The results show that during single events, the 10 min runoff intensities were reduced by 10-36% for 5-10 years return period and 40-78% for 0.1-1 year return period; the runoff volumes were reduced by 2-5% for 5-10 years return period and 18-28% for 0.1-1 year return period. Annual runoff volumes were estimated to be 43-68% of the total precipitation. The peak time delay was found to greatly vary from 0 to more than 40 min depending on the type of event, and a general decrease in the time delay was observed for increasing rainfall intensities. Furthermore, the model was used to evaluate the variation of the average annual runoff from green roofs as a function of the total available storage and vegetation type. The results show that even a few millimeters of storage can reduce the mean annual runoff by up to 20% when compared to a traditional roof and that the mean annual runoff is not linearly related to the storage. Green roofs have therefore the potential to be important parts of future urban stormwater management plans.

  9. Retention performance of green roofs in representative climates worldwide

    Science.gov (United States)

    Viola, F.; Hellies, M.; Deidda, R.

    2017-10-01

    The ongoing process of global urbanization contributes to an increase in stormwater runoff from impervious surfaces, threatening also water quality. Green roofs have been proved to be innovative stormwater management measures to partially restore natural states, enhancing interception, infiltration and evapotranspiration fluxes. The amount of water that is retained within green roofs depends not only on their depth, but also on the climate, which drives the stochastic soil moisture dynamic. In this context, a simple tool for assessing performance of green roofs worldwide in terms of retained water is still missing and highly desirable for practical assessments. The aim of this work is to explore retention performance of green roofs as a function of their depth and in different climate regimes. Two soil depths are investigated, one representing the intensive configuration and another representing the extensive one. The role of the climate in driving water retention has been represented by rainfall and potential evapotranspiration dynamics. A simple conceptual weather generator has been implemented and used for stochastic simulation of daily rainfall and potential evapotranspiration. Stochastic forcing is used as an input of a simple conceptual hydrological model for estimating long-term water partitioning between rainfall, runoff and actual evapotranspiration. Coupling the stochastic weather generator with the conceptual hydrological model, we assessed the amount of rainfall diverted into evapotranspiration for different combinations of annual rainfall and potential evapotranspiration in five representative climatic regimes. Results quantified the capabilities of green roofs in retaining rainfall and consequently in reducing discharges into sewer systems at an annual time scale. The role of substrate depth has been recognized to be crucial in determining green roofs retention performance, which in general increase from extensive to intensive settings. Looking at the

  10. Roof collapse of shallow tunnels with limit analysis method

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-li; LONG Ze-xiang

    2015-01-01

    A new failure mechanism is proposed to analyze the roof collapse based on nonlinear failure criterion. Limit analysis approach and variational principle are used to obtain analytical findings concerning the stability of potential roof. Then, parametric study is carried out to derive the change rule of corresponding parameters on the influence of collapsing shape, which is of paramount engineering significance to instruct the tunnel excavations. In comparison with existing results, the findings show agreement and validity of the proposed method. The actual collapse in certain shallow tunnels is well in accordance with the proposed failure mechanism.

  11. Crystalline roof glazing - Westside shopping centre, Berne; Kristalline Dachverglasungen

    Energy Technology Data Exchange (ETDEWEB)

    Enkerli, W.

    2009-07-01

    This illustrated article takes a look at the new shopping and leisure centre on the western outskirts of Berne, Switzerland. In particular, the roof of this unusual building over the motorway with its sloping walls and zig-zag design is looked at. The centre's shopping mall, adventure baths and spa, a multiplex cinema, an old peoples' home and a hotel are briefly discussed, as is the embedding of the centre in its suburban environment. The roof construction with its crystalline skylights is examined and discussed in detail. The centre's building technical services are also briefly commented on.

  12. PLM floating-point interface program

    Energy Technology Data Exchange (ETDEWEB)

    Paoni, C.; Maples, M.

    1976-03-03

    A major failing of Intel's PLM language is its inability to handle scientific notation (floating-point) calculations. An interface program that allows PLM to perform such calculations is described. A comparison of this modified PLM with an assembly language program has shown PLM's effectiveness in reducing the cost of a project. (auth)

  13. Floating RC Networks Using Current Conveyors

    OpenAIRE

    Zeman, V; J. Cajka; Vrba, K.

    1996-01-01

    The paper deals with the design of floating one- and/or two-port high-order networks. The current conveyor CCII+ seems to be a suitable active building block for this purpose. Some examples of the above mentioned networks are shown .

  14. Floating RC Networks Using Current Conveyors

    Directory of Open Access Journals (Sweden)

    V. Zeman

    1996-06-01

    Full Text Available The paper deals with the design of floating one- and/or two-port high-order networks. The current conveyor CCII+ seems to be a suitable active building block for this purpose. Some examples of the above mentioned networks are shown .

  15. A novel floating offshore wind turbine concept

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Friis Pedersen, Troels

    2009-01-01

    This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water...

  16. Floating car data for traffic monitoring

    DEFF Research Database (Denmark)

    Torp, Kristian; Lahrmann, Harry Spaabæk

    2005-01-01

    This paper describes a complete prototype system that uses Floating Car Data (FCD) for both automatic and manual detection of queues in traffic. The system is developed under EU’s Tempo program. The systems consists of small hardware units placed in mobile traffic report units (we use taxis...

  17. Reis kosmosesse : [Floating-kambrist] / Marika Makarova

    Index Scriptorium Estoniae

    Makarova, Marika

    2011-01-01

    Ameerika psühholoogi John C. Lilly poolt kasutusele võetud Floating-kambrist ehk hõljumisvannist, mis aeglustab ajulaineid ning seeläbi aitab vähendada lihaspinget, stressi, ärevust, peavalusid, vererõhku ning parandada und, selgroo- ja kaelavigastusi, suurendada loovust ja heaolu jne

  18. Immunohistochemistry on freely floating fixed tissue sections.

    Science.gov (United States)

    Bachman, Julia

    2013-01-01

    Immunohistochemistry on free floating tissue sections is done for many reasons, all of which involve labeling tissue to visualize a certain cell type, protein, or structural component. Visualization is aided by mounting sections on microscope slides for stabilization, and is in most cases necessary for the appropriate use of objectives with a high numerical aperture and high degree of magnification.

  19. Two New Families of Floating FDNR Circuits

    Directory of Open Access Journals (Sweden)

    Ahmed M. Soliman

    2010-01-01

    Full Text Available Two new configurations for realizing ideal floating frequency-dependent negative resistor elements (FDNR are introduced. The proposed circuits are symmetrical and are realizable by four CCII or ICCII or a combination of both. Each configuration is realizable by eight different circuits. Simulation results are included to support the theory.

  20. Floating Breakwater Prototype Test Program: Seattle, Washington.

    Science.gov (United States)

    1986-03-01

    foam weight increased 250 percent because of the absorption of water. This absorption, combined with underfilling of tires during the original...A 2 the float was done in three lifts of about 1 ft each. Handheld electric vibrators were used to reduce the possibility of voids . After the sides

  1. Near-Shore Floating Wave Energy Converters

    DEFF Research Database (Denmark)

    Ruol, Piero; Zanuttigh, Barbara; Martinelli, Luca

    2011-01-01

    Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency...

  2. Reis kosmosesse : [Floating-kambrist] / Marika Makarova

    Index Scriptorium Estoniae

    Makarova, Marika

    2011-01-01

    Ameerika psühholoogi John C. Lilly poolt kasutusele võetud Floating-kambrist ehk hõljumisvannist, mis aeglustab ajulaineid ning seeläbi aitab vähendada lihaspinget, stressi, ärevust, peavalusid, vererõhku ning parandada und, selgroo- ja kaelavigastusi, suurendada loovust ja heaolu jne

  3. Digging the New York City Skyline: soil fungal communities in green roofs and city parks.

    Science.gov (United States)

    McGuire, Krista L; Payne, Sara G; Palmer, Matthew I; Gillikin, Caitlyn M; Keefe, Dominique; Kim, Su Jin; Gedallovich, Seren M; Discenza, Julia; Rangamannar, Ramya; Koshner, Jennifer A; Massmann, Audrey L; Orazi, Giulia; Essene, Adam; Leff, Jonathan W; Fierer, Noah

    2013-01-01

    In urban environments, green roofs provide a number of benefits, including decreased urban heat island effects and reduced energy costs for buildings. However, little research has been done on the non-plant biota associated with green roofs, which likely affect their functionality. For the current study, we evaluated whether or not green roofs planted with two native plant communities in New York City functioned as habitats for soil fungal communities, and compared fungal communities in green roof growing media to soil microbial composition in five city parks, including Central Park and the High Line. Ten replicate roofs were sampled one year after planting; three of these roofs were more intensively sampled and compared to nearby city parks. Using Illumina sequencing of the fungal ITS region we found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils. Phospholipid fatty acid analysis revealed that park soils had greater microbial biomass and higher bacterial to fungal ratios than green roof substrates. City park soils were also more enriched with heavy metals, had lower pH, and lower quantities of total bases (Ca, K, and Mg) compared to green roof substrates. While fungal communities were compositionally distinct across green roofs, they did not differentiate by plant community. Together, these results suggest that fungi living in the growing medium of green roofs may be an underestimated component of these biotic systems functioning to support some of the valued ecological services of green roofs.

  4. Digging the New York City Skyline: soil fungal communities in green roofs and city parks.

    Directory of Open Access Journals (Sweden)

    Krista L McGuire

    Full Text Available In urban environments, green roofs provide a number of benefits, including decreased urban heat island effects and reduced energy costs for buildings. However, little research has been done on the non-plant biota associated with green roofs, which likely affect their functionality. For the current study, we evaluated whether or not green roofs planted with two native plant communities in New York City functioned as habitats for soil fungal communities, and compared fungal communities in green roof growing media to soil microbial composition in five city parks, including Central Park and the High Line. Ten replicate roofs were sampled one year after planting; three of these roofs were more intensively sampled and compared to nearby city parks. Using Illumina sequencing of the fungal ITS region we found that green roofs supported a diverse fungal community, with numerous taxa belonging to fungal groups capable of surviving in disturbed and polluted habitats. Across roofs, there was significant biogeographical clustering of fungal communities, indicating that community assembly of roof microbes across the greater New York City area is locally variable. Green roof fungal communities were compositionally distinct from city parks and only 54% of the green roof taxa were also found in the park soils. Phospholipid fatty acid analysis revealed that park soils had greater microbial biomass and higher bacterial to fungal ratios than green roof substrates. City park soils were also more enriched with heavy metals, had lower pH, and lower quantities of total bases (Ca, K, and Mg compared to green roof substrates. While fungal communities were compositionally distinct across green roofs, they did not differentiate by plant community. Together, these results suggest that fungi living in the growing medium of green roofs may be an underestimated component of these biotic systems functioning to support some of the valued ecological services of green roofs.

  5. Using ground penetrating radar for roof hazard detection in underground mines. Report of investigations/1996

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.D.; Mowrey, G.L.; Persetic, G.F.

    1996-08-01

    Ground penetrating radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>1/4 in zone) or rider beds in coal measure roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  6. Moessbauer spectra of tin in float glass

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.A. [Liverpool John Moores Univ. (United Kingdom). Sch. of the Built Environ.; Johnson, C.E. [Liverpool Univ. (United Kingdom). Dept. of Physics; Williams, K.F.E. [Liverpool Univ. (United Kingdom). Dept. of Physics; Holland, D. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Karim, M.M. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics

    1995-03-01

    Tin is not a major constituent of window glass, but is found at high concentrations in the lower surface of float glass which has been in contact with the molten tin bath. It does not extend far into the surface, but causes the physical and chemical behaviour to differ from that of the upper surface. It is important, therefore, to understand the structural role of tin in silicate glasses and thus its effect on various properties. Moessbauer spectra were taken of three series of glassy materials, namely binary glasses (SnO and SiO{sub 2}) in varying proportions, re-melted float glass containing tin, and float glass from a production plant. The binary glasses contained between 20 and 70% tin which was found to be mainly Sn{sup 2+}, with very small amounts of Sn{sup 4+} in some of them. The spectra showed a small decrease in isomer shift with increase in tine content, which is ascribed to the change in molar volume. The re-melted samples were float glass which was mixed with stannous oxalate in appropriate conditions to try and maintain tin in the 2+ state, and contained up to 15% tin by weight. The spectra show both Sn{sup 4+} and Sn{sup 2+} with rather more in the 4+ oxidation state. The change in the spectra as a function of temperature revealed a large difference in the f-factor (and hence the chemical binding) of the two states. A series of spectra was taken between 17.5 and 900 K for the sample containing 15% tin. From the absorption as a function of temperature the f-factor was determined for both oxidation states, and hence enabled the relative amounts of Sn{sup 4+} and Sn{sup 2+} present in each sample to be estimated. Measurements of the shift as a function of temperature were also made. The float samples were surface material produced by grinding away all but 0.1 mm of the lower surface of industrially produced float glass. The Moessbauer spectra showed them to be predominantly Sn{sup 2+}, as expected from the reducing atmosphere in the float plant.

  7. Development of floating strip micromegas detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bortfeldt, Jonathan

    2014-04-28

    Micromegas are high-rate capable, high-resolution micro-pattern gaseous detectors. Square meter sized resistive strip Micromegas are foreseen as replacement of the currently used precision tracking detectors in the Small Wheel, which is part of the forward region of the ATLAS muon spectrometer. The replacement is necessary to ensure tracking and triggering performance of the muon spectrometer after the luminosity increase of the Large Hadron Collider beyond its design value of 10{sup 34} cm{sup -2}s{sup -1} around 2020. In this thesis a novel discharge tolerant floating strip Micromegas detector is presented and described. By individually powering copper anode strips, the effects of a discharge are confined to a small region of the detector. This reduces the impact of discharges on the efficiency by three orders of magnitude, compared to a standard Micromegas. The physics of the detector is studied and discussed in detail. Several detectors are developed: A 6.4 x 6.4 cm{sup 2} floating strip Micromegas with exchangeable SMD capacitors and resistors allows for an optimization of the floating strip principle. The discharge behavior is investigated on this device in depth. The microscopic structure of discharges is quantitatively explained by a detailed detector simulation. A 48 x 50 cm{sup 2} floating strip Micromegas is studied in high energy pion beams. Its homogeneity with respect to pulse height, efficiency and spatial resolution is investigated. The good performance in high-rate background environments is demonstrated in cosmic muon tracking measurements with a 6.4 x 6.4 cm{sup 2} floating strip Micromegas under lateral irradiation with 550 kHz 20 MeV proton beams. A floating strip Micromegas doublet with low material budget is developed for ion tracking without limitations from multiple scattering in imaging applications during medical ion therapy. Highly efficient tracking of 20 MeV protons at particle rates of 550 kHz is possible. The reconstruction of the

  8. System for monitoring of green roof performance: use of weighing roof segment and non-invasive visualization

    Science.gov (United States)

    Jelinkova, Vladmira; Dohnal, Michal; Picek, Tomas; Sacha, Jan

    2015-04-01

    Understanding the performance of technogenic substrates for green roofs is a significant task in the framework of sustainable urban planning and water/energy management. The potential retention and detention of the anthropogenic, light weight soil systems and their temporal soil structure changes are of major importance. A green roof test segment was built to investigate the benefits of such anthropogenic systems. Adaptable low-cost system allows long-term monitoring of preferred characteristics. Temperature and water balance measurements complemented with meteorological observations and knowledge of physical properties of the substrates provide basis for detailed analysis of thermal and hydrological regime in green roof systems. The first results confirmed the benefits of green roof systems. The reduction of temperature fluctuations as well as rainfall runoff was significant. Depending on numerous factors such substrate material or vegetation cover the test green roof suppressed the roof temperature amplitude for the period analyzed. The ability to completely prevent (light rainfall events) or reduce and delay (medium and heavy rainfall events) the peak runoff was also analyzed. Special attention is being paid to the assessment of soil structural properties related to possible aggregation/disaggregation, root growth, weather conditions and associated structural changes using non-invasive imaging method. X-ray computed microtomography of undisturbed soil samples (taken from experimental segments) is used for description of pore space geometry, evaluation of surface to volume ratio, additionally for description of cracks and macropores as a product of soil flora and fauna activity. The information from computed tomography imaging will be used for numerical modeling of water flow in variable saturated porous media. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech

  9. 40 CFR 443.30 - Applicability; description of the asphalt roofing subcategory.

    Science.gov (United States)

    2010-07-01

    ... asphalt roofing subcategory. 443.30 Section 443.30 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Roofing Subcategory § 443.30 Applicability; description of the asphalt roofing subcategory. The provisions of this subpart are applicable to...

  10. Who governs climate adaptation? Getting green roofs for stormwater retention off the ground

    NARCIS (Netherlands)

    Mees, H.L.P.; Driessen, P.P.J.; Runhaar, H.A.C.; Stamatelos, J.

    2013-01-01

    Green roofs are an innovative solution for urban stormwater management. This paper examines governance arrangements for green roofs as a ‘no-regrets’ climate adaptation measure in five cities. We analysed who governs green roofs, why and with what outcome. Our results show that hierarchical and mark

  11. Effect of green roofs on air temperature; measurement study of well-watered and dry conditions

    Science.gov (United States)

    Solcerova, Anna; van de Ven, Frans; Wang, Mengyu; van de Giesen, Nick

    2016-04-01

    Rapid urbanization and increasing number and duration of heat waves poses a need for understanding urban climate and ways to mitigate extremely high temperatures. One of repeatedly suggested and often investigated methods to moderate the so called urban heat island are green roofs. This study investigates several extensive green roofs in Utrecht (NL) and their effect on air temperature right above the roof surface. Air temperature was measured 15 and 30 cm above the roof surface and also in the substrate. We show that under normal condition is air above green roof, compared to white gravel roof, colder at night and warmer during day. This suggest that green roofs might help decrease air temperatures at night, when the urban heat island is strongest, but possibly contribute to high temperatures during daytime. We also measured situation when the green roofs wilted and dried out. Under such conditions green roof exhibits more similar behavior to conventional white gravel roof. Interestingly, pattern of soil temperature remains almost the same for both dry and well-prospering green roof, colder during day and warmer at night. As such, green roof works as a buffer of diurnal temperature changes.

  12. Potential benefits of plant diversity on vegetated roofs: a literature review.

    Science.gov (United States)

    Cook-Patton, Susan C; Bauerle, Taryn L

    2012-09-15

    Although vegetated green roofs can be difficult to establish and maintain, they are an increasingly popular method for mitigating the negative environmental impacts of urbanization. Most green roof development has focused on maximizing green roof performance by planting one or a few drought-tolerant species. We present an alternative approach, which recognizes green roofs as dynamic ecosystems and employs a diversity of species. We draw links between the ecological and green roof literature to generate testable predictions about how increasing plant diversity could improve short- and long-term green roof functioning. Although we found few papers that experimentally manipulated diversity on green roofs, those that did revealed ecological dynamics similar to those in more natural systems. However, there are many unresolved issues. To improve overall green roof performance, we should (1) elucidate the links among plant diversity, structural complexity, and green roof performance, (2) describe feedback mechanisms between plant and animal diversity on green roofs, (3) identify species with complementary traits, and (4) determine whether diverse green roof communities are more resilient to disturbance and environmental change than less diverse green roofs.

  13. Wind loads on stand-off photovoltaic systems on pitched roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Blackmore, P.

    2013-01-01

    Stand-off photovoltaic systems are a popular measure for retrofitting of existing pitched roofs.Panels are generally mounted parallel to the existing roof coverings,usually roofing tiles.Full scale and wind tunnel experiments have been performed to determine the net uplift loads on these systems, wh

  14. Evaluation of Green Roof Water Quantity and Quality Performance in an Urban Climate

    Science.gov (United States)

    In this report we present an analysis of water benefits from an array of observed green roof and control (non-vegetated) roof project sites throughout NYC. The projects are located on a variety of building sites and represent a diverse set of available extensive green roof instal...

  15. Evaluation of Green Roof Plants and Materials for Semi-Arid Climates

    Science.gov (United States)

    Abstract While green roof systems have proven to be highly effective in the evaporative cooling of buildings, reduction of roof top temperatures, protection of roof membranes from solar radiation degradation, reducing stormwater runoff, as well as beautification of the urban roo...

  16. Green Roofs: A Part of Green Infrastructure Strategy for Urban Areas

    Science.gov (United States)

    This is a presentation on the basics of green roof technology. The presentation highlights some of the recent ORD research projects on green roofs and provides insight for the end user as to the benefits for green roof technology. It provides links to currently available EPA rep...

  17. Analysis of mechanical behaviors of big pipe roof for shallow buried large-span tunnel

    Institute of Scientific and Technical Information of China (English)

    Li Jian; Tan Zhongsheng; Yu Yu; Guo Xiaohong

    2013-01-01

    A series of researches on mechanical behaviors of big pipe roof for shallow large-span loess tunnel were carried out based on the Wenxiang tunnel in Zhengzhou-Xi’an Special Passenger Railway. The longitudinal de-formations of the pipe roofs were monitored and the mechanical behaviors of the pipe roofs were analyzed at the test section. A new double-parameter elastic foundation beam model for pipe roof in shallow tunnels was put for-ward in Wenxiang tunnel. The measured values and the calculation results agreed well with each other,revealing the force-deformation law of big pipe roof in loess tunnel:At about 15 m in front of the excavating face,the pipe roof starts to bear the load;at about 15 m behind the excavating face,the force of the pipe roof tends to be stabi-lized;the longitudinal deformation of the whole pipe roofs is groove-shaped distribution,and the largest force of pipe roofs is at the excavating face. Simultaneously,the results also indicate that mechanical behaviors of pipe roof closely relate to the location of the excavation face,the footage of the tunnelling cycle and the mechanics pa-rameters of pipe roof and rock. The conclusions can be reference for the design parameter optimization and the con-struction scheme selection of pipe roofs,and have been verified by the result of numerical analysis software FLAC3D and deformation monitoring.

  18. Thermally insulating green roof with model function. Roof gardens gain acceptance; Waermedaemmendes Gruendach mit Vorbildfunktion. Dachbegruenung macht Schule

    Energy Technology Data Exchange (ETDEWEB)

    Appl, Roland [ZinCo GmbH, Unterensingen (Germany)

    2010-07-01

    The new built consolidated school for physically disabled and speech handicapped persons in the Swabian Dettingen/Teck (Federal Republic of Germany) has a model function in every sense. This school provides a space for the promotion and personal development for more than 120 pupils from the region around Kirchheim (Federal Republic of Germany). In addition, a kindergarten for speech handicapped infants is integrated. The school is future-oriented and exemplary not only in its function, but also in its outside form. Wood as a naturally grown building material covers the fronts, and plants decorate the roofs. The heat insulating roof planting makes a substantial contribution to the structural thermal protection.

  19. Asphalt and Wood Shingling. Roofing Workbook and Tests.

    Science.gov (United States)

    Brown, Arthur

    This combination workbook and set of tests contains materials on asphalt and wood shingling that have been designed to be used by those studying to enter the roofing and waterproofing trade. It consists of seven instructional units and seven accompanying objective tests. Covered in the individual units are the following topics: shingling…

  20. Wind loads on solar energy systems, mounted on flat roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bentum, C.A. van; Blackmore, P.

    2005-01-01

    Wind loads on solar energy systems are not covered by current wind loading standards. This paper describes results of a parametric study into the wind loads on solar energy systems, which are placed on flat roofs. Wind tunnel measurements have been carried out on a number of configurations. The resu

  1. Collapse of the roof of a football stadium

    NARCIS (Netherlands)

    Borsje, H.; Renier, B.; Burggraaf, H.G.

    2014-01-01

    In the summer of 2011 the Dutch football club FC Twente was building an extension of their stadium De Grolsch Veste, to increase the capacity of the stadium. On july 7th 2011, during construction, the roof of the partially finished extension collapsed. As a result of this accident two workers were

  2. THERMAL INFRARED INSPECTION OF ROOF INSULATION USING UNMANNED AERIAL VEHICLES

    Directory of Open Access Journals (Sweden)

    J. Zhang

    2015-08-01

    Full Text Available UAVs equipped with high-resolution thermal cameras provide an excellent investigative tool used for a multitude of building-specific applications, including roof insulation inspection. We have presented in this study a relative thermographic calibration algorithm and a superpixel Markov Random Field model to address problems in thermal infrared inspection of roof insulation using UAVs. The relative thermographic radiometric calibration algorithm is designed to address the autogain problem of the thermal camera. Results show the algorithm can enhance the contrast between warm and cool areas on the roof surface in thermal images, and produces more constant thermal signatures of different roof insulations or surfaces, which could facilitate both visual interpretation and computer-based thermal anomaly detection. An automatic thermal anomaly detection algorithm based on superpixel Markov Random Field is proposed, which is more computationally efficient than pixel based MRF, and can potentially improve the production throughput capacity and increase the detection accuracy for thermal anomaly detection. Experimental results show the effectiveness of the proposed method.

  3. Evaluation of green roof characteristics in green building assessment

    Directory of Open Access Journals (Sweden)

    Sekulić Mirjana

    2013-01-01

    Full Text Available Methodology of building evaluation based on green building characteristics is rapidly gaining momentum, mainly in foreign, but also in domestic building practice. This methodology is being carried out through different Green Building Certification Systems, which are complex evaluation mechanisms based on numerous criteria of sustainability, addressing both ecological issues, but also economic and social ones. Green roof represents one of the 'must have' features of contemporary buildings aiming to gain green label. This paradigm is based on their numerous characteristics which contribute to different aspects of building sustainability, among which are savings in energy and water consumption, but also ecological balance and quality of built environment. Criteria used for evaluation of green roof solutions and their overall contribution to the building, are integral part of all of the mentioned certification systems, but the way they are structured and formulated inside each system varies significantly, hence causing differences in evaluation results. This paper presents the analysis of green roof related criteria of three characteristic green building certification systems: LEED, BREEAM and CASBEE. These systems are chosen primarily because of the different evaluation methodology, but also because of their market prevalence and perspectives of usage in the domestic practice. Conclusions driven from these analyses and comparisons provide insight into main aspect of green roof planning and construction which are relevant for the overall building sustainability assessment.

  4. Demonstration of Three Corrosion-Resistant Sustainable Roofing Systems

    Science.gov (United States)

    2013-06-01

    panel using grommet-type metal fasteners with neoprene sleeves. Next, the crew installed the gutter piece over the eave flashing. The roof panels were...in Figure 33). The attachment was made using the fas- teners having the neoprene sleeves placed at every-other high rib. Figure 32. View showing

  5. 30 CFR 75.206 - Conventional roof support.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conventional roof support. 75.206 Section 75.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... square inches. (d) Materials other than wood used for support shall have support strength at...

  6. Green Roof Research through EPA's Regional Applied Research Effort - slides

    Science.gov (United States)

    The U.S. Environmental Protection Agency’s (EPA) Regional Applied Research Effort (RARE) allows the Regions of the EPA to choose research projects to be performed in partnership with EPA’s Office of Research and Development (ORD). Over the last decade, several green roof projects...

  7. Wind loads on solar energy systems, mounted on flat roofs

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bentum, C.A. van; Blackmore, P.

    2005-01-01

    Wind loads on solar energy systems are not covered by current wind loading standards. This paper describes results of a parametric study into the wind loads on solar energy systems, which are placed on flat roofs. Wind tunnel measurements have been carried out on a number of configurations. The resu

  8. Urban reconciliation ecology: the potential of living roofs and walls.

    Science.gov (United States)

    Francis, Robert A; Lorimer, Jamie

    2011-06-01

    Reconciling human and non-human use of urban regions to support biological conservation represents a major challenge for the 21st century. The concept of reconciliation ecology, by which the anthropogenic environment may be modified to encourage non-human use and biodiversity preservation without compromising societal utilization, potentially represents an appropriate paradigm for urban conservation given the generally poor opportunities that exist for reserve establishment and ecological restoration in urban areas. Two habitat improvement techniques with great potential for reconciliation ecology in urban areas are the installation of living roofs and walls, which have been shown to support a range of taxa at local scales. This paper evaluates the reconciliation potential of living roofs and walls, in particular highlighting both ecological and societal limitations that need to be overcome for application at the landscape scale. We further consider that successful utilization of living roofs and walls for urban reconciliation ecology will rely heavily on the participation of urban citizens, and that a 'citizen science' model is needed to facilitate public participation and support and to create an evidence base to determine their effectiveness. Living roofs and walls are just one aspect of urban reconciliation ecology, but are particularly important 'bottom-up' techniques for improving urban biodiversity that can be performed directly by the citizenry.

  9. Collapse of the roof of a football stadium

    NARCIS (Netherlands)

    Borsje, H.; Renier, B.; Burggraaf, H.G.

    2014-01-01

    In the summer of 2011 the Dutch football club FC Twente was building an extension of their stadium De Grolsch Veste, to increase the capacity of the stadium. On july 7th 2011, during construction, the roof of the partially finished extension collapsed. As a result of this accident two workers were k

  10. Predictive Service Life Tests for Roofing Membranes: Phase 1

    Science.gov (United States)

    1993-12-01

    April 1991), pp 37-38, 40, 42, 44, 46. Puterman . M., K.H. Reinhorn, and M. Marton, "Specifications for Quality Assurance of Single-Ply Membrane...Material." Third International Symposium on Roofing Technology (NRCA, 1991), pp 271-275. Puterman , M., I. Soroka, and A. Bentur, "Deterioration of

  11. Survey of the Pagoda Timber Roof in Derneburg Castle

    Science.gov (United States)

    Perria, E.; Sieder, M.; Hoyer, S.; Krafczyk, C.

    2017-05-01

    The work analyses the historical roof of Derneburg Castle, in the municipality of Holle, Hildesheim's district, Lower Saxony, Germany. The roof is assembled according to Laves Balken's system (Laves beam's system), developed by the architect Georg Ludwig Friedrich Laves (1788-1864). The system has the peculiarity to consist of beams that are split along the half of the cross section, and maintained diverged by wooden wedges, distributed along the length of the beam. The system increases the height of the beam, and elevates the bending capacity of it (Weber, 1964). The work has been developed in the frame of an interdisciplinary project in the fields of architecture, engineering and photogrammetry. Main aim of the project is the developing of a structural model to understand the load-carrying capacity of Laves Balken's system from the laser-scanning model. For this reason, extensive surveys and photo documentation were collected on three areas of the roof construction, characterized by three peculiar usage of Laves Balken's system. The work presents the survey of the pagoda-roof that covers the tower of the castle, and problems that can be encountered during the survey of very complex timber constructions.

  12. Field Testing Unvented Roofs with Asphalt Shingles in Cold and Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Kohta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lstiburek, Joseph W. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Insulating roofs with dense-pack cellulose (instead of spray foam) has moisture risks, but is a lower cost approach. If moisture risks could be addressed, buildings could benefit from retrofit options, and the ability to bring HVAC systems within the conditioned space. Test houses with unvented roof assemblies were built to measure long-term moisture performance, in the Chicago area (5A) and the Houston area (2A). The Chicago-area test bed had seven experimental rafter bays, including a control vented compact roof, and six unvented roof variants with cellulose or fiberglass insulation. The interior was run at 50% RH. All roofs except the vented cathedral assembly experienced wood moisture contents and RH levels high enough to constitute failure. Disassembly at the end of the experiment showed that the unvented fiberglass roofs had wet sheathing and mold growth. In contrast, the cellulose roofs only had slight issues, such as rusted fasteners and sheathing grain raise. The Houston-area roof was an unvented attic insulated with spray-applied fiberglass. Most ridges and hips were built with a diffusion vent detail, capped with vapor permeable roof membrane. Some ridge sections were built as a conventional unvented roof, as a control. In the control unvented roofs, roof peak RHs reached high levels in the first winter; as exterior conditions warmed, RHs quickly fell. In contrast, the diffusion vent roofs had drier conditions at the roof peak in wintertime, but during the summer, RHs and MCs were higher than the unvented roof (albeit in the safe range).

  13. Urban heat mitigation by roof surface materials during the East Asian summer monsoon

    Science.gov (United States)

    Lee, Seungjoon; Ryu, Youngryel; Jiang, Chongya

    2015-12-01

    Roof surface materials, such as green and white roofs, have attracted attention in their role in urban heat mitigation, and various studies have assessed the cooling performance of roof surface materials during hot and sunny summer seasons. However, summers in the East Asian monsoon climate region are characterized by significant fluctuations in weather events, such as dry periods, heatwaves, and rainy and cloudy days. This study investigated the efficacy of different roof surface materials for heat mitigation, considering the temperatures both at and beneath the surface of the roof covering materials during a summer monsoon in Seoul, Korea. We performed continuous observations of temperature at and beneath the surface of the roof covering materials, and manual observation of albedo and the normalized difference vegetation index for a white roof, two green roofs (grass (Poa pratensis) and sedum (Sedum sarmentosum)), and a reference surface. Overall, the surface temperature of the white roof was significantly lower than that of the grass and sedum roofs (1.1 °C and 1.3 °C), whereas the temperature beneath the surface of the white roof did not differ significantly from that of the grass and sedum roofs during the summer. The degree of cloudiness significantly modified the surface temperature of the white roof compared with that of the grass and sedum roofs, which depended on plant metabolisms. It was difficult for the grass to maintain its cooling ability without adequate watering management. After considering the cooling performance and maintenance efforts for different environmental conditions, we concluded that white roof performed better in urban heat mitigation than grass and sedum during the East Asian summer monsoon. Our findings will be useful in urban heat mitigation in the region.

  14. A Case Study of Effective Support Working Resistance and Roof Support Technology in Thick Seam Fully-Mechanized Face Mining with Hard Roof Conditions

    Directory of Open Access Journals (Sweden)

    Wei-bin Guo

    2017-06-01

    Full Text Available This paper presents the engineering geological properties and roof control tecnology for a thick coal seam fully-mechanized face mining with hard roof conditions (THC at the Jinhuagong Coal Mine (JCM, northwest China. The effective support working resistance and appropriate roof control technology are two critical factors for safe and productive mining in the THC. The load-estimate-method (LOEM is the effective method to determine the support working resistance for normal working conditions (the mining height less than 3.5 m. In order to prevent support crushing accidents from happening and to ensure the safety and high-efficiency in the THC, the LOEM was modified based on the structure of the overlying strata in the THC. The strata which can form the voussoir beam structure in normal working conditions and will break in the form of cantilever beam in the THC is defined as the key strata in the immediate roof. Therefore, the hanging length of the key strata in the immediate roof was considered in the LOEM. Furthermore, a method for calculating the hanging length of the key strata in the immediate roof and its influencing factors were proposed using cantilever beam theory analysis of the structure of the overlying strata. Moreover, in order to fully fill the goaf area with caving roof to reduce the energy accumulation of main roof movement, it was decided to apply destress blasting technique (DEBT at the JCM to control the large hanging length of the hard roof, so as to reduce the impact of the hard main roof movement on the working face. The key technique parameters of the roof caving borehole were also proposed. The obtained results demonstrated that the theoretical analysis is reasonable, and the chosen support type and the DEBT could meet the roof control requirements. The THC has achieved safety and high-efficiency mining.

  15. Roof Weakening of Hydraulic Fracturing for Control of Hanging Roof in the Face End of High Gassy Coal Longwall Mining: A Case Study

    Science.gov (United States)

    Huang, Bingxiang; Wang, Youzhuang

    2016-09-01

    The occurence of hanging roof commonly arises in the face end of longwall coal mining under hard roof conditions. The sudden break and subsequent caving of a hanging roof could result in the extrusion of gas in the gob to the face, causing gas concentrations to rise sharply and to increase to over a safety-limited value. A series of linear fracturing-holes of 32 mm diameter were drilled into the roof of the entries with an anchor rig. According to the theory that the gob should be fully filled with the fragmentized falling roof rock, the drilling depth is determined as being 3 5 times the mining height if the broken expansion coefficient takes an empirical value. Considering the general extension range of cracks and the supporting form of the entryway, the spacing distance between two drilling holes is determined as being 1 2 times the crack's range of extension. Using a mounting pipe, a high pressure resistant sealing device of a small diameter-size was sent to the designated location for the high-pressure hydraulic fracturing of the roof rock. The hydraulic fracturing created the main hydro-fracturing crack and airfoil branch cracks in the interior of the roof-rock, transforming the roof structure and weakening the strength of the roof to form a weak plane which accelerated roof caving, and eventually induced the full caving in of the roof in time with the help of ground pressure. For holes deeper than 4 m, retreating hydraulic fracturing could ensure the uniformity of crack extension. Tested and applied at several mines in Shengdong Mining District, the highest ruptured water pressure was found to be 55 MPa, and the hanging roof at the face end was reduced in length from 12 m to less than 1 2 m. This technology has eliminated the risk of the extrusion of gas which has accumulated in the gob.

  16. Using ground penetrating radar for roof hazard detection in underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.P.; Mowrey, G.L. [Dept. of Energy, Pittsburgh, PA (United States)

    1996-12-31

    Ground Penetrating Radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>{1/4} in zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologic changes in the roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  17. Using ground penetrating radar for roof hazard detection in underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Molinda, G.M.; Monaghan, W.P.; Mowrey, G.L.; Persetic, G.F. [Department of Energy, Pittsburgh, PA (United States)

    1996-12-01

    Ground Penetrating Radar (GPR) is being investigated for the potential to determine roof hazards in underground mines. GPR surveys were conducted at four field sites with accompanying ground truth in order to determine the value of GPR for roof hazard detection. The resolution of the current system allows detection of gross roof fractures (>63 cm (>1/4 in) zone) or rider beds in coal measure roof. Data quality is not yet sufficient to detect small bed separations or subtle lithologic changes in the roof. Differences in data quality are discussed, as well as suggestions for collecting improved data.

  18. The External Degree.

    Science.gov (United States)

    Houle, Cyril O.

    This book examines the external degree in relation to the extremes of attitudes, myths, and data. Emphasis is placed on the emergence of the American external degree, foreign external-degree programs, the purpose of the external degree, the current scene, institutional issues, and problems of general policy. (MJM)

  19. Assessment of green roof systems in terms of water and energy balance

    Directory of Open Access Journals (Sweden)

    Mert Ekşi

    2016-01-01

    Full Text Available Green roofs concept term is used for extensive green roofs which are planted with herbaceous plants that can be adapted into changeable environmental conditions on a shallow substrate layer, require minimal maintenance, installed for their benefits to building and urban scale. Main objective of this study is to determine the characteristics of a green roof such as thermal insulation, water holding capacity, runoff characteristics, plant growth and its interaction with environmental factors in Istanbul climate conditions by performing comparative measurements. In this study, a research site (IU Green Roof Research Station was founded to assess water and energy balance of green roofs. Thus, a typical green roof was evaluated in terms of water and energy balance and its interaction with the building and city was determined. energy efficiency of green roof system was 77% higher than reference roof. Temperature fluctuations on green roof section of the roof were 79% lower. In addition, green roof retained 12,8% - 100% of precipitation and delayed runoff up to 23 hours depending on water content of substrate.

  20. Theoretical relationships between first flush of roof runoff and influencing factors

    Institute of Scientific and Technical Information of China (English)

    Biao WANG; Tian LI

    2009-01-01

    Considering the short length of building roofs,a theoretical analysis of the first flush of roof runoff was conducted based on the kinematic wave and pollutant erosion equations.This mathematical derivation with analytical solutions predicts pollutant mass first flush(MFF),mean concentration of initial runoff(MCIF),mean concentration of roof runoff(MCRRl with diversion of initial portion and residual mass available on the bed surface (RS) after the entire rnnoff under the condition of constant excess rainfall.And the effects of the associated influencing factors(roof length,roof gradient,roof surface roughness.rainfall intensity,rainfall duration,and erosion coefficients)on them were discussed while the values of parameters referred to the previous studies.The results showed that for roofs whose length is shorter than 20 m.both the increase in roof length and roof gradient and the decrease in roof surface roughness result in larger MFF and MCIF and smaller MCRR and RS.which is beneficial to water reuse and pollution reduction.The theoretical relationship between the first flush and the influencing factors may aid the planning and design of roof in terms of rainwater utilization or diffuse pollution control.

  1. Experimental Heat Transfer Study on Green Roofs in a Semiarid Climate during Summer

    Directory of Open Access Journals (Sweden)

    Roy J. Issa

    2015-01-01

    Full Text Available An experimental study was conducted on green roofs under the semiarid summer climatic conditions of West Texas to investigate the effect of soil type, moisture content, and the presence of a top soil grass layer on the conductive heat transfer through the roof. Two soil types were investigated: uniform sand and local silt clay. Tests were also conducted on a control roof. A dual-needle heat-pulse sensor was used to conduct thermal property tests on the soils. The tests reveal that unlike sand, the thermal conductivity of silt clay did not increase continuously with soil moisture. Better heat transfer conditions were achieved when the sand and silt clay roofs were watered to a water depth of 10 mm per day rather than double the amount of 20 mm per day. The roof with silt clay soil had the lowest fluctuation in inner temperature between daytime and nighttime. Green roofs with silt clay soil required more than twice the amount of soil moisture than green roofs with sand to achieve similar roof heat transfer rates. The best net heat flux gains for vegetated green roofs were 4.7 W/m2 for the sand roof and 7.8 W/m2 for the silt clay roof.

  2. Characteristics of Residual Atrial Posterior Wall and Roof-Dependent Atrial Tachycardias after Pulmonary Vein Isolation.

    Science.gov (United States)

    Matsumoto, Akinori; Fukuzawa, Koji; Kiuchi, Kunihiko; Konishi, Hiroki; Ichibori, Hirotoshi; Imada, Hiroshi; Hyogo, Kiyohiro; Kurose, Jun; Takaya, Tomofumi; Mori, Shumpei; Yoshida, Akihiro; Hirata, Ken-Ichi; Nishii, Tatsuya; Kono, Atsushi

    2016-10-01

    Roof-dependent atrial tachycardia (roof AT) sometimes occurs after pulmonary vein isolation (PVI) of atrial fibrillation (AF). This study aimed to investigate the relationship between the anatomy of the residual left atrial posterior wall and occurrence of roof AT. A total of 265 patients with AF who underwent PVI were enrolled. After the PVI, induced or recurrent roof AT was confirmed by an entrainment maneuver or activation mapping using a three-dimensional (3D) mapping system. To identify the predictors of roof AT, the minimum distance between both PVI lines (d-PVI) was measured by a 3D mapping system and the anatomical parameters, including the left atrial (LA) diameter, left atrial volume index (LAVi), and shape of the left atrial roof, were analyzed by 3D computed tomography. Roof AT was documented in 11 (4.2%) of 265 patients. A multivariable analysis demonstrated that the d-PVI, Deep V shape of the LA roof, and LAVi were associated with roof AT occurrences (d-PVI: odds ratio: 0.72, confidence interval [CI]: 0.61-0.86, P PVI and LAVi, respectively. The shorter d-PVI at the LA roof, greater LAVi, and Deep V shape were associated with the occurrence of a roof AT. © 2016 Wiley Periodicals, Inc.

  3. Field Testing of an Unvented Roof with Fibrous Insulation, Tiles, and Vapor Diffusion Venting

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States); Lstiburek, J. W. [Building Science Corporation, Westford, MA (United States)

    2016-02-01

    This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design.

  4. A Review of Methods for the Manufacture of Residential Roofing Materials

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Levinson, Ronnen; Berdahl, Paul

    2003-06-01

    Shingles, tiles, and metal products comprise over 80% (by roof area) of the California roofing market (54-58% fiberglass shingle, 8-10% concrete tile, 8-10% clay tile, 7% metal, 3% wood shake, and 3% slate). In climates with significant demand for cooling energy, increasing roof solar reflectance reduces energy consumption in mechanically cooled buildings, and improves occupant comfort in non-conditioned buildings. This report examines methods for manufacturing fiberglass shingles, concrete tiles, clay tiles, and metal roofing. The report also discusses innovative methods for increasing the solar reflectance of these roofing materials. We have focused on these four roofing products because they are typically colored with pigmented coatings or additives. A better understanding of the current practices for manufacturing colored roofing materials would allow us to develop cool colored materials creatively and more effectively.

  5. A multiple floating point coprocessor architecture

    Energy Technology Data Exchange (ETDEWEB)

    Rauchwerger, L.; Farmwald, M.P. (Center for Supercomputing Research and Development, Univ. of Illinois at Urbana-Champaign, 305 Talbot Lab., Urbana, IL (US))

    1990-06-01

    General purpose microprocessor based computers usually speed their arithmetic processing performance by using a floating point co-processor. Because adding more co-processors represents neither a technological nor a cost problem the authors investigated a system based on a MIPS R2000 (2) and 4 floating point units. In this paper they show a block diagram of such an implementation and how two important scientific operations can be accelerated using a single unmodified data bus. A large percentage of the engineering applications are solved with the help of linear algebra methods like BLAS3 (4) algorithms; it is precisely for these primitives that the proposed architecture brings significant performance gains. The first operation described is a matrix multiplication algorithm, its timing diagram and some results. Next a polynomial evaluation technique is examined. The authors show how to use the same ideas with various other microprocessors.

  6. Optimizing polynomials for floating-point implementation

    CERN Document Server

    De Dinechin, Florent

    2008-01-01

    The floating-point implementation of a function on an interval often reduces to polynomial approximation, the polynomial being typically provided by Remez algorithm. However, the floating-point evaluation of a Remez polynomial sometimes leads to catastrophic cancellations. This happens when some of the polynomial coefficients are very small in magnitude with respects to others. In this case, it is better to force these coefficients to zero, which also reduces the operation count. This technique, classically used for odd or even functions, may be generalized to a much larger class of functions. An algorithm is presented that forces to zero the smaller coefficients of the initial polynomial thanks to a modified Remez algorithm targeting an incomplete monomial basis. One advantage of this technique is that it is purely numerical, the function being used as a numerical black box. This algorithm is implemented within a larger polynomial implementation tool that is demonstrated on a range of examples, resulting in ...

  7. Capillary deposition of advected floating particles

    Science.gov (United States)

    Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico

    2016-11-01

    The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.

  8. Seismic Response of Submerged Floating Tunnel Tether

    Institute of Scientific and Technical Information of China (English)

    SU Zhi-bin; SUN Sheng-nan

    2013-01-01

    A mathematical equation for vibration of submerged floating tunnel tether under the effects of earthquake and parametric excitation is presented.Multi-step Galerkin method is used to simplify this equation and the fourth-order Runge-Kuta integration method is used for numerical analysis.Finally,vibration response of submerged floating tunnel tether subjected to earthquake and parametric excitation is analyzed in a few numerical examples.The results show that the vibration response of tether varies with the seismic wave type; the steady maximum mid-span displacement of tether subjected to seismic wave keeps constant when parametric resonance takes place; the transient maximum mid-span displacement of tether is related to the peak value of input seismic wave acceleration.

  9. Can Oil Float Completely Submerged in Water?

    CERN Document Server

    Nath, Saurabh; Chatterjee, Souvick

    2013-01-01

    Droplet formation in a system of two or more immiscible fluids is a celebrated topic of research in the fluid mechanics community. In this work, we propose an innovative phenomenon where oil when injected drop-wise into a pool of water moves towards the air-water interface where it floats in a fully submerged condition. The configuration, however, is not stable and a slight perturbation to the system causes the droplet to burst and float in partially submerged condition. The droplet contour is analyzed using edge detection. Temporal variation of a characteristic length of the droplet is analyzed using MATLAB image processing. The constraint of small Bond Number established the assumption of lubrication regime in the thin gap. A brief theoretical formulation also showed the temporal variation of the gap thickness

  10. Conceptual Design of Navy Floating Pier.

    Science.gov (United States)

    1982-09-01

    which do not have existing flood basins or dry dock facilities. 3.1.3 The Advantages As Navy Piers The floating pier provides a structure well suited to...Bureau of Yards and Docks built 13 reinforced concrete floating repair docks each of 280 ton lift capacity. Bach dock was 390 ft. long, 80 ft. wide and...4 176CK ApoQ &LLKHC-AP6, COLUMNN AND eAr4b V~JricAL- roA~~scN LY T’B 4OPr~C-. I200-+0k 𔄀 CELLO £TNAT STRUCTUARAL EN4GINEERING " NrE FZ IR MJUə

  11. Migration Laws of Floating Population in Mianyang

    Institute of Scientific and Technical Information of China (English)

    LiuPeng

    2005-01-01

    Based on the overall anatysis of the floating population among big and medium-sized cities in China, this paper, by means of statistics and questionnaires, makes a systematical study on the migratory features of the floating population in Mianyang, its employment structure, migrating causes and channels, According to the findings, the author finds a fact that with the strategy of Western Development, and with the construction of science and technology city of Mianyang, the migrating in Mianyang conforms to the general patterns of themigration, which has happened in those big and medium-sized cities in China. In addition, the city has a new but unique feature - economic factor, as the driving force of popufation migration, is quite distinct from that of those cities in eastern areas of China.

  12. FLOATING DRUG DELIVERY SYSTEM - CHRONOTHERAPEUTIC APPROACH

    Directory of Open Access Journals (Sweden)

    Vishal Kalal

    2011-04-01

    Full Text Available The purpose of writing this review on the floating drug delivery systems (FDDS was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. FDDS is one of the approaches in chronotherapeutic drug delivery. In the past reviews of FDDS the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, their classification and formulation aspects have been covered. This review summarizes the special focus on chronotherapeutics, diseases affected by biological rhythm, its importance, advantages, various approaches in Chronotherapeutic drug delivery and applications of FDDS. These systems are useful for several problems encountered during the development of a pharmaceutical dosage forms.

  13. Voltage-Controlled Floating Resistor Using DDCC

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2011-04-01

    Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

  14. Management of "floating elbow" in children

    Directory of Open Access Journals (Sweden)

    Suresh S

    2007-01-01

    Full Text Available Background: Supracondylar fractures associated with ipsilateral forearm fractures, aptly termed as "floating elbow" is a rare injury in children after a fall from height. The various authors report their results with conservative treatment of one or both injury to aggressive emergency operative fixation of both components. Materials and Methods: During a period of three years, the author managed four cases of floating elbow in children. All cases were managed by closed reduction and pinning of both components of the injury. Results: All patients recovered full elbow range of motion at three months followup and were rated as excellent as per modified Flynn′s criteria. None of the patients developed cubitus varus deformity, complications related to the pins or delayed union. Conclusions: Early closed reduction and K wire fixation of both components of this injury gives better stability and prevents development of complications like compartment syndrome and elbow deformities.

  15. Floating behavior of hydrophobic glass spheres.

    Science.gov (United States)

    Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng

    2009-08-15

    When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results.

  16. Arithmetic Operations Beyond Floating Point Number Precision

    CERN Document Server

    Wang, Chih-Yueh; Chen, Hong-Yu; Chen, Yung-Ko

    2010-01-01

    In basic computational physics classes, students often raise the question of how to compute a number that exceeds the numerical limit of the machine. While technique of avoiding overflow/underflow has practical application in the electrical and electronics engineering industries, it is not commonly utilized in scientific computing, because scientific notation is adequate in most cases. We present an undergraduate project that deals with such calculations beyond a machine's numerical limit, known as arbitrary precision arithmetic. The assignment asks students to investigate the validity of floating point number precision and the approach of calculating the exact value of a large number, using the basic scientific programming language Fortran. Examples of the successive multiplication of even number and the multiplication and division of two overflowing floats are presented. The application of the scheme to hardware and firmware design which requires the allocation of finite memory, as in a digital signal proce...

  17. Segmentation of Sloped Roofs from Airborne LiDAR Point Clouds Using Ridge-Based Hierarchical Decomposition

    Directory of Open Access Journals (Sweden)

    Hongchao Fan

    2014-04-01

    Full Text Available This paper presents a new approach for roof facet segmentation based on ridge detection and hierarchical decomposition along ridges. The proposed approach exploits the fact that every roof can be composed of a set of gabled roofs and single facets which are separated by the gabled roofs. In this work, firstly, building footprints stored in OpenStreetMap are used to extract 3D points on roofs. Then, roofs are segmented into roof facets. The algorithm starts with detecting roof ridges using RANSAC since they are parallel to the horizon and situated on the top of the roof. The roof ridges are utilized to indicate the location and direction of the gabled roof. Thus, points on the two roof facets along a roof ridge can be identified based on their connectivity and coplanarity. The results of the segmentation benefit the further process of roof reconstruction because many parameters, including the position, angle and size of the gabled roof can be calculated and used as priori knowledge for the model-driven approach, and topologies among the point segments are made known for the data-driven approach. The algorithm has been validated in the test sites of two towns next to Bavaria Forest national park. The experimental results show that building roofs can be segmented with both high correctness and completeness simultaneously.

  18. 49 CFR 571.118 - Standard No. 118; Power-operated window, partition, and roof panel systems.

    Science.gov (United States)

    2010-10-01

    ...-operated window, partition, and roof panel systems. S1. Purpose and scope. This standard specifies requirements for power operated window, partition, and roof panel systems to minimize the likelihood of death... Figure 2. Power operated roof panel systems mean moveable panels in the vehicle roof which close...

  19. Synthesizing Accurate Floating-Point Formulas

    OpenAIRE

    Ioualalen, Arnault; Martel, Matthieu

    2013-01-01

    International audience; Many critical embedded systems perform floating-point computations yet their accuracy is difficult to assert and strongly depends on how formulas are written in programs. In this article, we focus on the synthesis of accurate formulas mathematically equal to the original formulas occurring in source codes. In general, an expression may be rewritten in many ways. To avoid any combinatorial explosion, we use an intermediate representation, called APEG, enabling us to rep...

  20. Implementation of Floating-point Coprocessor

    OpenAIRE

    Skogstrøm, Kristian

    2005-01-01

    This thesis presents the architecture and implementation of a high-performance floating-point coprocessor for Atmel's new microcontroller. The coprocessor architecture is based on a fused multiply-add pipeline developed in the specialization project, TDT4720. This pipeline has been optimized significantly and extended to support negation of all operands and single-precision input and output. New hardware has been designed for the decode/fetch unit, the register file, the compare/convert pipe...

  1. Termination of floating-point computations

    OpenAIRE

    Serebrenik, Alexander; De Schreye, Danny

    2005-01-01

    Numerical computations form an essential part of almost any real-world program. Traditional approaches to termination of logic programs are restricted to domains isomorphic to (N,>); more recent works study termination of integer computations where the lack of well-foundedness of the integers has to be taken into account. Termination of computations involving floating-point numbers can be counterintuitive because of rounding errors and implementation conventions. We present a novel technique ...

  2. Floating gate transistors as biosensors (Conference Presentation)

    Science.gov (United States)

    Frisbie, C. Daniel

    2016-11-01

    Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.

  3. Ships as future floating farm systems?

    Science.gov (United States)

    Moustafa, Khaled

    2016-09-29

    Environmental and agriculture challenges such as severe drought, desertification, sprawling cities and shrinking arable lands in large regions in the world compel us to think about alternative and sustainable farming systems. Ongoing projects to build floating cities in the sea suggest that building specific ships for farming purposes (as farming ships or farming boats) would also be attainable to introduce new farming surfaces and boost food production worldwide to cope with food insecurity issues.

  4. Floating asphalt blocks of the Dead Sea

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, A. (Weizmann Inst. of Science, Rehovot, Israel); Aizenshtat, Z.; Goldberg, M.

    1980-01-01

    Large blocks of mineral matter free (less than 0.1%) asphalt are occasionally found floating on the surface of the Dead Sea. Chemical, spectroscopic and isotopic data are given for the asphalt. The source of the asphalt is not accurately known, but presumably it represents mobilization of heavy viscous asphaltic masses at depth below the lake bottom into the floor of the lake. It may be released to the surface by earth tremors.

  5. Turbomachinery systems for floating production applications

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Jonathan P.; Kurz, Rainer [Solar Turbines Incorporated, San Diego, CA (United States)

    2008-07-01

    Since 1995 there has been a dramatic increase in oil and gas exploration and production using floating platforms in deeper waters located further offshore. This exploration started with tension leg platforms, progressed through SPARs and Semi-Submersibles, and later evolved into Floating Production Storage and Offloading (FPSO) vessels. Turbomachinery equipment installed on a floating platform or vessel will be expected to operate in the same manner as a land based machine, but in a variety of climate and environmental conditions that now includes motion. To operate successfully, specific design considerations for the turbo-machinery packages are required. It is critical to take into account the type of vessel, the expected list, trim and dynamic motion angles, the dynamic forces applied, the expected deck deflection as a result of those forces, understand the applicable class requirement, and where the equipment will be located on the vessel. This information is then translated into the design conditions to determine the type of mounting method to be used to attach the turbo-machinery package to the deck, the expected accelerations for structural analysis, and oil tank and system designs for fluid management. Furthermore, compressor designs need to allow utmost flexibility to adapt to changing operating conditions. (author)

  6. Soft Roof Failure Mechanism and Supporting Method for Gob-Side Entry Retaining

    Directory of Open Access Journals (Sweden)

    Hongyun Yang

    2015-10-01

    Full Text Available To study the soft roof failure mechanism and the supporting method for a gateway in a gently inclined coal seam with a dip angle of 16° kept for gob-side entry retaining, and through the methodology of field investigation and numerical and analytical modeling, this paper analyzed the stress evolution law of roof strata at the working face end and determined that the sharp horizontal stress unloading phenomenon along the coal wall side did not appear after the working face advanced. Conversely, the horizontal stress along the gob side instantly decreased and the tensile stress produced, and the vertical stress in the central part of the roof had a higher reduction magnitude as well. An in-depth study indicates that the soft roof of the working face end subsided and seriously separated due to the effect of the front abutment pressure and the roof hanging length above the gob line, as well as certain other factors, including the rapid unloading of the lateral stress, tension and shear on the lower roof rock layer and dynamic disturbance. Those influencing factors also led to rapid crack propagation on a large scale and serious fracturing in the soft roof of the working face end. However, in the gob stress stabilized zone, the soft roof in the gob-side entry retaining has a shearing failure along the filling wall inside affected by the overburden pressure, rock bulking pressure, and roof gravity. To maintain the roof integrity, decrease the roof deformation, and enable the control of the working face end soft roof and the stabilization of the gob-side entry retaining roof, this study suggests that the preferred bolt installation angle for the soft roof situation is 70° based on the rock bolt extrusion strengthening theory.

  7. The effect of roofing material on the quality of harvested rainwater.

    Science.gov (United States)

    Mendez, Carolina B; Klenzendorf, J Brandon; Afshar, Brigit R; Simmons, Mark T; Barrett, Michael E; Kinney, Kerry A; Kirisits, Mary Jo

    2011-02-01

    Due to decreases in the availability and quality of traditional water resources, harvested rainwater is increasingly used for potable and non-potable purposes. In this study, we examined the effect of conventional roofing materials (i.e., asphalt fiberglass shingle, Galvalume(®) metal, and concrete tile) and alternative roofing materials (i.e., cool and green) on the quality of harvested rainwater. Results from pilot-scale and full-scale roofs demonstrated that rainwater harvested from any of these roofing materials would require treatment if the consumer wanted to meet United States Environmental Protection Agency primary and secondary drinking water standards or non-potable water reuse guidelines; at a minimum, first-flush diversion, filtration, and disinfection are recommended. Metal roofs are commonly recommended for rainwater harvesting applications, and this study showed that rainwater harvested from metal roofs tends to have lower concentrations of fecal indicator bacteria as compared to other roofing materials. However, concrete tile and cool roofs produced harvested rainwater quality similar to that from the metal roofs, indicating that these roofing materials also are suitable for rainwater harvesting applications. Although the shingle and green roofs produced water quality comparable in many respects to that from the other roofing materials, their dissolved organic carbon concentrations were very high (approximately one order of magnitude higher than what is typical for a finished drinking water in the United States), which might lead to high concentrations of disinfection byproducts after chlorination. Furthermore the concentrations of some metals (e.g., arsenic) in rainwater harvested from the green roof suggest that the quality of commercial growing media should be carefully examined if the harvested rainwater is being considered for domestic use. Hence, roofing material is an important consideration when designing a rainwater catchment.

  8. Optimizing the building envelopes with green roofs : a discussion of architectural and energy performance requirements

    Energy Technology Data Exchange (ETDEWEB)

    Hagerman, J. [Columbia Univ., New York, NY (United States). Dept. of Civil Engineering]|[Rafael Vinoly Architects, New York, NY (United States); Hodge, D. [Rafael Vinoly Architects, New York, NY (United States)

    2006-07-01

    This paper provided recommendations for optimized green roof technologies inspired by an architect firm's involvement in designing a 255,000 square foot green roof on top of the Howard Hughes Medical Institute's Janelia Farm Research Campus in Virginia. During the course of the green roof construction and installation, the architects found that green roofs needed design flexibility to meet their conceptual design requirements. It was suggested that the use of a modular system might allow for easier inspection access as well as the ability for the planting material to be reconfigured. It was noted that green roof systems can sometimes conflict with water management strategies of the building envelope. Green roof component lists do not make reference to the layers of construction within the building envelope, as it is often assumed that they are irrelevant to green roof design. Modular products offer Architects flexibility in design and maintenance, and products can be incorporated into more sophisticated water management details, offering simplicity of design, ease of installation, and ease of roof membrane inspection. A thermal analysis of modular and monolithic roof assemblies was conducted which showed that the assemblies contributed very little to the overall thermal insulation envelope when the positive thermal benefits of the green roof failed. It was recommended that green roof installations should be designed to sit directly on top of the roof membranes to replace the building's insulation envelope. Foamglas was proposed as a material for building insulation and to prevent root penetration. An evaluation of the R-values of various green roof systems at failure was also provided to give guidance to Architects incorporating green roofs in building envelopes. 3 refs., 3 tabs., 8 figs.

  9. Energy Performance Impacts from Competing Low-slope Roofing Choices and Photovoltaic Technologies

    Science.gov (United States)

    Nagengast, Amy L.

    With such a vast quantity of space, commercial low-slope roofs offer significant potential for sustainable roofing technology deployment. Specifically, building energy performance can be improved by installing rooftop energy technologies such as photovoltaic (PV) panels, and/or including designs such as white or green roofs instead of traditional black. This research aims to inform and support roof decisions through quantified energy performance impacts across roof choices and photovoltaic technologies. The primary dataset for this research was measured over a 16 month period (May 24, 2011 to October 13, 2012) from a large field experiment in Pittsburgh, Pennsylvania on top of a commercial warehouse with white, black and green roof sections, each with portions covered by polycrystalline photovoltaic panels. Results from the Pittsburgh experiment were extended to three different cities (San Diego, CA; Huntsville, AL; and Phoenix, AZ) chosen to represent a wide range of irradiance and temperature values. First, this research evaluated the difference in electricity production from a green-moss roof and black roof underneath photovoltaic panels to determine if the green roof's cooler air increases the panel efficiency. Second, separate studies examine 1) average hourly heat flux by month for unobstructed and shaded roof membranes 2) heat flux peak time delay, and 3) air temperature across roof types. Results of this research show green roofs slightly increased (0.8-1.5%) PV panel efficiency in temperatures approximately at or above 25° C (77°F) compared to black roofs. However in cool climates, like Pittsburgh, the roof type under the PV panels had little overall impact on PV performance when considering year round temperatures. Instead, roof decisions should place a stronger emphasis on heat flux impacts. The green roof outperformed both black and white roofs at minimizing total conductive heat flux. These heat flow values were used to develop a new, straight

  10. INVESTIGATION OF SOLAR ABSORPTANCE OF BUILDING EXTERNAL SURFACES FROM HEAT FLUX POINT OF VIEW

    Directory of Open Access Journals (Sweden)

    Meral ÖZEL

    2006-02-01

    Full Text Available In this study, solar absorptance of external surfaces of buildings has been numerically investigated from the heat gain and losses point of view. For this purpose, external surface solar absorptance was icreased from 0 to 1with an ratio of 0.1 and, for the summer and winter conditions, heat fluxs was calculated by considering orientations of the wall and its roof for brick and concrete structure materials. Besides, external surface absorptance was assumed as 0.2, 0.5 and 0.9, respectively. Than, heat gain and losses were calculated to insulation thickness increasing on the outdoor surface of wall. Results obtained were presented as graphics

  11. Green roof impact on the hydrological cycle components

    Science.gov (United States)

    Lamera, Carlotta; Rulli, Maria Cristina; Becciu, Gianfranco; Rosso, Renzo

    2013-04-01

    In the last decades the importance of storm water management in urban areas has increased considerably, due to both urbanization extension and to a greater concern for environment pollution. Traditional storm water control practices, based on the "all to the sewer" attitude, rely on conveyance to route storm water runoff from urban impervious surfaces towards the nearby natural water bodies. In recent years, infiltration facilities are receiving an increasing attention, due to their particular efficiency in restoring a balance in hydrological cycle quite equal to quite pre-urbanization condition. In particular, such techniques are designed to capture, temporarily retain and infiltrate storm water, promote evapotranspiration and harvest water at the source, encouraging in general evaporation, evapotranspiration, groundwater recharge and the re-use of storm water. Green roofs are emerging as an increasingly popular Sustainable Urban Drainage Systems (SUDS) technique for urban storm water management. Indeed, they are able to operate hydrologic control over storm water runoff: they allow a significant reduction of peak flows and runoff volumes collected by drainage system, with a consequent reduction of flooding events and pollution masses discharges by CSO. Furthermore green roofs have a positive influence on the microclimate in urban areas by helping in lower urban air temperatures and mitigate the heat island effect. Last but not least, they have the advantage of improving the thermal insulation of buildings, with significant energy savings. A detailed analysis of the hydrological dynamics, connected both with the characteristics of the climatic context and with the green roof technical design, is essential in order to obtain a full characterization of the hydrologic behavior of a green roof system and its effects on the urban water cycle components. The purpose of this paper is to analysis the hydrological effects and urban benefits of the vegetation cover of a

  12. Float processing of high-temperature complex silicate glasses and float baths used for same

    Science.gov (United States)

    Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)

    2000-01-01

    A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.

  13. Floating Oil-Spill Containment Device

    Science.gov (United States)

    Jones, Jack A.

    2012-01-01

    Previous oil containment booms have an open top that allows natural gas to escape, and have significant oil leakage due to wave action. Also, a subsea pyramid oil trap exists, but cannot move relative to moving oil plumes from deepsea oil leaks. The solution is to have large, moveable oil traps. One version floats on the sea surface and has a flexible tarp cover and a lower weighted skirt to completely entrap the floating oil and natural gas. The device must have at least three sides with boats pulling at each apex, and sonar or other system to track the slowly moving oil plume, so that the boats can properly locate the booms. The oil trap device must also have a means for removal of the oil and the natural gas. A second design version has a flexible pyramid cover that is attached by lines to ballast on the ocean floor. This is similar to fixed, metal pyramid oil capture devices in the Santa Barbara Channel off the coast of California. The ballast lines for the improved design, however, would have winches that can move the pyramid to always be located above the oil and gas plume. A third design is a combination of the first two. It uses a submerged pyramid to trap oil, but has no anchor and uses boats to locate the trap. It has ballast weights located along the bottom of the tarp and/or at the corners of the trap. The improved floating oil-spill containment device has a large floating boom and weighted skirt surrounding the oil and gas entrapment area. The device is triangular (or more than three sides) and has a flexible tarp cover with a raised gas vent area. Boats pull on the apex of the triangles to maintain tension and to allow the device to move to optimum locations to trap oil and gas. The gas is retrieved from a higher buoyant part of the tarp, and oil is retrieved from the floating oil layer contained in the device. These devices can be operated in relatively severe weather, since waves will break over the devices without causing oil leaking. Also, natural

  14. It's Alive! Spontaneous Motion of Shear Thickening Fluids Floating on the Air-Water Interface

    CERN Document Server

    Khandavalli, Sunilkumar; Rothstein, Jonathan P

    2013-01-01

    In this fluid dynamics video, we show the spontaneous random motion of thin filaments of a shear-thickening colloidal dispersions floating on the surface of water. The fluid is a dispersion of fumed silica nanoparticles in a low molecular weight polypropylene glycol (PPG) solvent. No external field or force is applied. The observed motion is driven by strong surface tension gradients as the polypropylene glycol slowly diffuses from from the filaments into water, resulting in the observed Marangoni flow. The motion is exaggerated by the thin filament constructs by the attractive interactions between silica nanoparticles and the PPG.

  15. Influence of Floating Monitoring Platform Structure on the Hydrostatic Characteristics

    Directory of Open Access Journals (Sweden)

    Su Feng

    2015-01-01

    Full Text Available According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.

  16. When chromatin organisation floats astray: the Srcap gene and Floating-Harbor syndrome.

    Science.gov (United States)

    Messina, Giovanni; Atterrato, Maria Teresa; Dimitri, Patrizio

    2016-12-01

    Floating-Harbor syndrome (FHS) is a rare human disease characterised by delayed bone mineralisation and growth deficiency, often associated with mental retardation and skeletal and craniofacial abnormalities. FHS was first described at Boston's Floating Hospital 42 years ago, but the causative gene, called Srcap, was identified only recently. Truncated SRCAP protein variants have been implicated in the mechanism of FHS, but the molecular bases underlying the disease must still be elucidated and investigating the molecular defects leading to the onset of FHS remains a challenge. Here we comprehensively review recent work and provide alterative hypotheses to explain how the Srcap truncating mutations lead to the onset of FHS.

  17. Variable Torque Control of Offshore Wind Turbine on Spar Floating Platform Using Advanced RBF Neural Network

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2014-01-01

    Full Text Available Offshore floating wind turbine (OFWT has been a challenging research spot because of the high-quality wind power and complex load environment. This paper focuses on the research of variable torque control of offshore wind turbine on Spar floating platform. The control objective in below-rated wind speed region is to optimize the output power by tracking the optimal tip-speed ratio and ideal power curve. Aiming at the external disturbances and nonlinear uncertain dynamic systems of OFWT because of the proximity to load centers and strong wave coupling, this paper proposes an advanced radial basis function (RBF neural network approach for torque control of OFWT system at speeds lower than rated wind speed. The robust RBF neural network weight adaptive rules are acquired based on the Lyapunov stability analysis. The proposed control approach is tested and compared with the NREL baseline controller using the “NREL offshore 5 MW wind turbine” model mounted on a Spar floating platform run on FAST and Matlab/Simulink, operating in the below-rated wind speed condition. The simulation results show a better performance in tracking the optimal output power curve, therefore, completing the maximum wind energy utilization.

  18. Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting

    Science.gov (United States)

    Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M.; Choi, Yang-Kyu

    2015-01-01

    A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157 V and instantaneous short-circuit current of 4.6 μA, within sub-10 Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running. PMID:26553524

  19. Floating microbial fuel cells as energy harvesters for signal transmission from natural water bodies

    Science.gov (United States)

    Schievano, Andrea; Colombo, Alessandra; Grattieri, Matteo; Trasatti, Stefano P.; Liberale, Alessandro; Tremolada, Paolo; Pino, Claudio; Cristiani, Pierangela

    2017-02-01

    A new type of floating microbial fuel cell (fMFC) was developed for power supply of remote environmental sensors and data transmission. Ten operating fMFCs generated a cell potential in the range 100-800 mV depending on the external resistance applied. Power production peaked around 3-3.5 mW (power density of 22-28 mW m-2 cathode) after about 20-30 days of start-up period. The average of daily electrical energy harvested ranged between 10 and 35 mWh/d. Long-term performances were ensured in the presence of dense rice plants (Oryza Sativa). A power management system, based on a step-up DC/DC converter and a low-power data transmission system via SIGFOX™ technology, have been set up for the fMFCs. The tested fMFCs systems allowed to: i) harvest produced energy, ii) supply electronic devices (intermittent LED-light and a buzzer); iii) transmit remote data at low speed (three message of 12 bites each, in 6 s). Several 'floating garden' MFCs were set in the context of demonstrative events at EXPO2015 world exposition held in Milan between May-October 2015. Some of the 'floating garden' MFCs were operating for more than one year.

  20. Regulating multiple externalities

    DEFF Research Database (Denmark)

    Waldo, Staffan; Jensen, Frank; Nielsen, Max

    2016-01-01

    Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory instrume......Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory...

  1. Trident: An FPGA Compiler Framework for Floating-Point Algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Tripp J. L. (Justin L.); Peterson, K. D. (Kristopher D.); Poznanovic, J. D. (Jeffrey Daniel); Ahrens, C. M. (Christine Marie); Gokhale, M. (Maya)

    2005-01-01

    Trident is a compiler for floating point algorithms written in C, producing circuits in reconfigurable logic that exploit the parallelism available in the input description. Trident automatically extracts parallelism and pipelines loop bodies using conventional compiler optimizations and scheduling techniques. Trident also provides an open framework for experimentation, analysis, and optimization of floating point algorithms on FPGAs and the flexibility to easily integrate custom floating point libraries.

  2. Implementing decimal floating-point arithmetic through binary: some suggestions

    OpenAIRE

    Brisebarre, Nicolas; Ercegovac, Milos; Louvet, Nicolas; Martin-Dorel, Erik; Muller, Jean-Michel; Panhaleux, Adrien

    2010-01-01

    International audience; We propose several algorithms and provide some related results that make it possible to implement decimal floating-point arithmetic on a processor that does not have decimal operators, using the available binary floating-point functions. In this preliminary study, we focus on round-to-nearest mode only. We show that several functions in decimal32 and decimal64 arithmetic can be implemented using binary64 and binary128 floating-point arithmetic, respectively. Specifical...

  3. ExternE National Implementation Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K.; Maelkki, H.; Wihersaari, M.; Pirilae, P. [VTT Energy, Espoo (Finland); Hongisto, M. [Imatran Voima Oy, Vantaa (Finland); Siitonen, S. [Ekono Energy Ltd, Espoo (Finland); Johansson, M. [Finnish Environment Institute, Helsinki (Finland)

    1999-07-01

    ExternE National Implementation is a continuation of the ExternE Project, funded in part by the European Commission's Joule III Programme. This study is the result of the ExternE National Implementation Project for Finland. Three fuel cycles were selected for the Finnish study: coal, peat and wood-derived biomass, which together are responsible for about 40% of total electricity generation in Finland and about 75% of the non-nuclear fuel based generation. The estimated external costs or damages were dominated by the global warming (GW) impacts in the coal and peat fuel cycles, but knowledge of the true GW impacts is still uncertain. From among other impacts that were valued in monetary terms the human health damages due to airborne emissions dominated in all the three fuel cycles. Monetary valuation for ecosystem impacts is not possible using the ExternE methodology at present. The Meri-Pori power station representing the coal fuel cycle is one of the world's cleanest and most efficient coal-fired power plants with a condensing turbine. The coal is imported mainly from Poland. The estimated health damages were about 4 mECU/kWh, crop damages an order of magnitude lower and damages caused to building materials two orders of magnitude lower. The power stations of the peat and biomass fuel cycles are of CHP type, generating electricity and heat for the district heating systems of two cities. Their fuels are of domestic origin. The estimated health damages allocated to electricity generation were about 5 and 6 mECU/kWh, respectively. The estimates were case-specific and thus an generalisation of the results to the whole electricity generation in Finland is unrealistic. Despite the uncertainties and limitations of the methodology, it is a promising tool in the comparison of similar kinds of fuel cycles, new power plants and pollution abatement technologies and different plant locations with each other. (orig.)

  4. Positive effects of vegetation: urban heat island and green roofs.

    Science.gov (United States)

    Susca, T; Gaffin, S R; Dell'osso, G R

    2011-01-01

    This paper attempts to evaluate the positive effects of vegetation with a multi-scale approach: an urban and a building scale. Monitoring the urban heat island in four areas of New York City, we have found an average of 2 °C difference of temperatures between the most and the least vegetated areas, ascribable to the substitution of vegetation with man-made building materials. At micro-scale, we have assessed the effect of surface albedo on climate through the use of a climatological model. Then, using the CO(2) equivalents as indicators of the impact on climate, we have compared the surface albedo, and the construction, replacement and use phase of a black, a white and a green roof. By our analyses, we found that both the white and the green roofs are less impactive than the black one; with the thermal resistance, the biological activity of plants and the surface albedo playing a crucial role.

  5. Towards a generic rainfall-runoff model for green roofs.

    Science.gov (United States)

    Kasmin, H; Stovin, V R; Hathway, E A

    2010-01-01

    A simple conceptual model for green roof hydrological processes is shown to reproduce monitored data, both during a storm event, and over a longer continuous simulation period. The model comprises a substrate moisture storage component and a transient storage component. Storage within the substrate represents the roof's overall stormwater retention capacity (or initial losses). Following a storm event the retention capacity is restored by evapotranspiration (ET). However, standard methods for quantifying ET do not exist. Monthly ET values are identified using four different approaches: analysis of storm event antecedent dry weather period and initial losses data; calibration of the ET parameter in a continuous simulation model; use of the Thornthwaite ET formula; and direct laboratory measurement of evaporation. There appears to be potential to adapt the Thornthwaite ET formula to provide monthly ET estimates from local temperature data. The development of a standardized laboratory test for ET will enable differences resulting from substrate characteristics to be quantified.

  6. Mechanical model of roof on stope and its analysis

    Institute of Scientific and Technical Information of China (English)

    WAGN Hong-wei; CHEN Zhong-hui; DU Ze-chao; ZHANG Jian

    2005-01-01

    Based on the engineering background of No.8402 stope face in Silaogou Coal Mine of Datong Mineral Bureau and the theory of plate presented by researchers before,considering surrounding rock structure in the stope and according to mechanical property of rock bodies with various kinds of joint planes, presented an assumption that the key roof was divided into a series of elastic plate group by joint planes, then set up mechanical model of elastic plate group with pin joint. After compared the deflection and the stress in the mechanical model by numerical modeling with data from field engineering, the rule of rock plates' break in turn and the difference in rock plates' stress during the roof's first and periodic weighting along the stope face were found.

  7. Stress fracture in acetabular roof due to motocross: case report

    Directory of Open Access Journals (Sweden)

    Alexandre de Paiva Luciano

    2016-06-01

    Full Text Available ABSTRACT One of the first steps to be taken in order to reduce sports injuries such as stress fractures is to have in-depth knowledge of the nature and extent of these pathological conditions. We present a case report of a stress fracture of the acetabular roof caused through motocross. This type of case is considered rare in the literature. The description of the clinical case is as follows. The patient was a 27-year-old male who started to have medical follow-up because of uncharacteristic pain in his left hip, which was concentrated mainly in the inguinal region of the left hip during motocross practice. After clinical investigation and complementary tests, he was diagnosed with a stress fracture of the acetabular roof.

  8. Stress fracture in acetabular roof due to motocross: case report.

    Science.gov (United States)

    de Paiva Luciano, Alexandre; Filho, Nelson Franco

    2016-01-01

    One of the first steps to be taken in order to reduce sports injuries such as stress fractures is to have in-depth knowledge of the nature and extent of these pathological conditions. We present a case report of a stress fracture of the acetabular roof caused through motocross. This type of case is considered rare in the literature. The description of the clinical case is as follows. The patient was a 27-year-old male who started to have medical follow-up because of uncharacteristic pain in his left hip, which was concentrated mainly in the inguinal region of the left hip during motocross practice. After clinical investigation and complementary tests, he was diagnosed with a stress fracture of the acetabular roof.

  9. Modeling Košice Green Roofs Maps

    Science.gov (United States)

    Poorova, Zuzana; Vranayova, Zuzana

    2017-06-01

    The need to house population in urban areas is expected to rise to 66% in 2050, according to United Nations. The replacement of natural permeable green areas with concrete constructions and hard surfaces will be noticed. The densification of existing built-up areas is responsible for the decreasing vegetation, which results in the lack of evapotranspiration cooling the air. Such decreasing vegetation causes urban heat islands. Since roofs and pavements have a very low albedo, they absorb a lot of sunlight. Several studies have shown that natural and permeable surfaces, as in the case of green roofs, can play crucial role in mitigating this negative climate phenomenon and providing higher efficiency for the building, leading to savings. Such as water saving, what is the main idea of this research.

  10. Identifying fall-protection training needs for residential roofing subcontractors.

    Science.gov (United States)

    Hung, Yu-Hsiu; Winchester, Woodrow W; Smith-Jackson, Tonya L; Kleiner, Brian M; Babski-Reeves, Kari L; Mills, Thomas H

    2013-05-01

    Falls remain the leading cause of injuries and fatalities in the small residential roofing industry and analogous investigations are underrepresented in the literature. To address this issue, fall-protection training needs were explored through 29 semi-structured interviews among residential roofing subcontractors with respect to recommendations for the design of fall-protection training. Content analysis using grounded theory was conducted to analyze participants' responses. Results of the analysis revealed six themes related to the design of current fall-protection training: (1) barriers to safety training; (2) problems of formal safety-training programs; (3) recommendations for training implementation; (4) important areas for fall-protection training; (5) training delivery means; and (6) design features of training materials. Results of the study suggest the need for informal jobsite safety training to complement what had been covered in formalized safety training. This work also provides recommendations for the design of a more likely adopted fall-protection training program.

  11. Free Vibration of Laminated Composite Hypar Shell Roofs with Cutouts

    Directory of Open Access Journals (Sweden)

    Sarmila Sahoo

    2011-01-01

    Full Text Available Use of laminated composites in civil engineering structural components including shell roofs is increasing day by day due to their light weight, high specific strength, and stiffness properties. In the present paper, laminated composite hypar shell (hyperbolic paraboloidal shells bounded by straight edges roofs with cutouts are analyzed for their free vibration characteristics using finite element method. An eight-noded curved shell element is used for modeling the shell. Specific numerical problems of earlier investigators are solved to compare their results with the present formulation. A number of problems are further solved where the size of the cutouts and their positions with respect to the shell centre are varied for different edge constraints. The results are furnished in the form of figures and tables. The results are examined thoroughly to arrive at some meaningful conclusions useful to designers.

  12. Modelling reduction of urban heat load in Vienna by modifying surface properties of roofs

    Science.gov (United States)

    Žuvela-Aloise, Maja; Andre, Konrad; Schwaiger, Hannes; Bird, David Neil; Gallaun, Heinz

    2017-01-01

    The study examines the potential of urban roofs to reduce the urban heat island (UHI) effect by changing their reflectivity and implementing vegetation (green roofs) using the example of the City of Vienna. The urban modelling simulations are performed based on high-resolution orography and land use data, climatological observations, surface albedo values from satellite imagery and registry of the green roof potential in Vienna. The modelling results show that a moderate increase in reflectivity of roofs (up to 0.45) reduces the mean summer temperatures in the densely built-up environment by approximately 0.25 °C. Applying high reflectivity materials (roof albedo up to 0.7) leads to average cooling in densely built-up area of approximately 0.5 °C. The green roofs yield a heat load reduction in similar order of magnitude as the high reflectivity materials. However, only 45 % of roof area in Vienna is suitable for greening and the green roof potential mostly applies to industrial areas in city outskirts and is therefore not sufficient for substantial reduction of the UHI effect, particularly in the city centre which has the highest heat load. The strongest cooling effect can be achieved by combining the green roofs with high reflectivity materials. In this case, using 50 or 100 % of the green roof potential and applying high reflectivity materials on the remaining surfaces have a similar cooling effect.

  13. Impact of green roofs on stormwater quality in a South Australian urban environment.

    Science.gov (United States)

    Razzaghmanesh, M; Beecham, S; Kazemi, F

    2014-02-01

    Green roofs are an increasingly important component of water sensitive urban design systems and can potentially improve the quality of urban runoff. However, there is evidence that they can occasionally act as a source rather than a sink for pollutants. In this study, the water quality of the outflow from both intensive and extensive green roof systems were studied in the city of Adelaide, South Australia over a period of nine months. The aim was to examine the effects of different green roof configurations on stormwater quality and to compare this with runoff from aluminium and asphalt roofs as control surfaces. The contaminant concentrations in runoff from both intensive and extensive green roofs generally decreased during the study period. A comparison between the two types of green roof showed that except for some events for EC, TDS and chloride, the values of the parameters such as pH, turbidity, nitrate, phosphate and potassium in intensive green roof outflows were higher than in the outflows from the extensive green roofs. These concentrations were compared to local, state, national and international water quality guidelines in order to investigate the potential for outflow runoff from green roofs to be reused for potable and non-potable purposes. The study found that green roof outflow can provide an alternative water source for non-potable purposes such as urban landscape irrigation and toilet flushing.

  14. Potted Plants on Flat Roof as a Strategy to Reduce Indoor Temperature in Malaysian Climate

    Directory of Open Access Journals (Sweden)

    Asmat Ismail

    2010-01-01

    Full Text Available Problem statement: The phenomenon of global warming or climate change has led to many environmental issues including higher atmospheric temperatures, intensive precipitation, increase greenhouse gaseous emission and of course increase indoor discomfort condition. Researchers worldwide collectively agreed that one way of reducing the impact of global warming is by implementing green roof technology which integrates vegetation, growing medium and water proofing membrane on top of the roof surface. However, none of them have ever studied on how much the potted plants on the roof top could contribute to lessen the environmental problems. Therefore, this study investigates the effect of potted plants on flat roof on the indoor temperature inside building in Malaysian climate. Approach: This study emphasized on experimental approach of the room with flat roof. Measurements were conducted in two phases i.e., room with potted plant on the roof and room with bare roof. The measurements were conducted on the same room. Results: The experiment showed a promising result whereby the average indoor temperature dropped between 0.21 and 1.73°C had been observed during the measurements, while average indoor surface temperatures difference between roof with potted plants and bare roof of 7.86°C had been recorded during daytime hour. Conclusion: Potted plants on flat roof had a great potential in reducing the indoor temperature of the room underneath and could contributed to the reduction of energy consumption in building.

  15. Field Testing of an Unvented Roof with Fibrous Insulation, Tiles and Vapor Diffusion Venting

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States); Lstiburek, J. W. [Building Science Corporation, Westford, MA (United States)

    2016-02-05

    This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design. The unvented roof had extended winter periods of 95-100% RH, and wafer (wood surrogate RH sensor) measurements indicating possible condensation; high moisture levels were concentrated at the roof ridge. In contrast, the diffusion vent roofs had drier conditions, with most peak MCs (sheathing) below 20%. In the spring, as outdoor temperatures warmed, all roofs dried well into the safe range (10% MC or less). Some roof-wall interfaces showed moderately high MCs; this might be due to moisture accumulation at the highest point in the lower attic, and/or shading of the roof by the adjacent second story. Monitoring will be continued at least through spring 2016 (another winter and spring).

  16. EXISTING PROBLEMS ANALYZIS OF ORGANIZATIONAL AND TECHNOLOGICAL RELIABILITY OF ROOFING SYSTEMS

    Directory of Open Access Journals (Sweden)

    A. V. Radkevich

    2015-03-01

    Full Text Available Purpose. The article aims at analysis of existing approaches towards engineering, construction, reconstruction and major repair of buildings roofing systems and constructions for solving the matters regarding organizational and technological reliability. Methodology. The survey is based on methods of analogy, scientific analysis and synthesis. Findings. The analysis of innovative technologies as well as new construction materials for roofing has been carried out. Problems regarding their organizational and technological reliability have been specified. Relevance of the given problems has been grounded. Correlation between reliability of constructed facility or roofing repair from thoroughly chosen technology and also construction process organization in general was determined. All the specifications influencing roofing organizational and technological reliability have been divided into primary and secondary. New methodic conception including all the constituents of roofing in the whole has been worked out. Ukrainian and European specification documents have been taking into account. Roofing organizational and technological reliability scheme considering the factors that form reliability has been suggested. An urgent need for creation of roofing model taking into consideration the innovative technologies and latest roofing materials for choosing its rational variant has been emerged. It has to meet both customers and specification documents requirements and also desired level of organizational and technological reliability. Originality. For the first time the notion of «organizational and technological reliability» has been applied to roofing. Fundamental investigation of this notion has been suggested. Roofing reliability dependence on all its components as a whole has been analyzed. New approach towards roofing problems solving conception has been developed. Practical value. The survey results may be applied at roofing engineering and

  17. Building America Case Study: Field Testing an Unvented Roof with Fibrous Insulation and Tiles, Orlando, Florida

    Energy Technology Data Exchange (ETDEWEB)

    2015-11-01

    This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a 'diffusion vent' (water vapor open, but air barrier 'closed') at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The 'diffusion vent' is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge). The data collected to date indicate that the diffusion vent roof shows greater moisture safety than the conventional, unvented roof design. The unvented roof had extended winter periods of 95-100% RH, and wafer (wood surrogate RH sensor) measurements indicating possible condensation; high moisture levels were concentrated at the roof ridge. In contrast, the diffusion vent roofs had drier conditions, with most peak MCs (sheathing) below 20%. In the spring, as outdoor temperatures warmed, all roofs dried well into the safe range (10% MC or less). Some roof-wall interfaces showed moderately high MCs; this might be due to moisture accumulation at the highest point in the lower attic, and/or shading of the roof by the adjacent second story. Monitoring will be continued at least through spring 2016 (another winter and spring).

  18. Manipulating particles for micro- and nano-fluidics via floating electrodes and diffusiophoresis

    Science.gov (United States)

    Yalcin, Sinan Eren

    The ability to accurately control micro- and nano-particles in a liquid is fundamentally useful for many applications in biology, medicine, pharmacology, tissue engineering, and microelectronics. Therefore, first particle manipulations are experimentally studied using electrodes attached to the bottom of a straight microchannel under an imposed DC or AC electric field. In contrast to a dielectric microchannel possessing a nearly-uniform surface charge, a floating electrode is polarized under the imposed electric field. The purpose is to create a non-uniform distribution of the induced surface charge, with a zero-net-surface charge along the floating electrode's surface. Such a field, in turn, generates an induced-charge electro-osmotic (ICED) flow near the metal strip. The demonstrations by using single and multiple floating electrodes at the bottom of a straight microchannel, with induced DC electric field, include particle enrichment, movement, trapping, reversal of motion, separation, and particle focusing. A flexible strategy for the on-demand control of the particle enrichment and positioning is also proposed and demonstrated by using a locally-controlled floating metal electrode. Then, under an externally imposed AC electric field, the particle deposition onto a floating electrode, which is placed in a closed circular cavity, has been experimentally investigated. In the second part of the study, another particle manipulation method was computationally investigated. The diffusiophoretic and electrodiffusiophoretic motion of a charged spherical particle in a nanopore is subjected to an axial electrolyte concentration gradient. The charged particle experiences electrophoresis because of the imposed electric field and the diffusiophoresis is caused solely by the imposed concentration gradient. Depending on the magnitude and direction of the imposed concentration gradient, the particle's electrophoretic motion can be accelerated, decelerated, and even reversed in

  19. Characteristic roofing slates from Spain: Mormeau and Los Molinos

    Science.gov (United States)

    Cardenes Van den Eynde, Victor; Cnudde, Veerle; Cnudde, Jean Pierre

    2014-05-01

    Characteristic roofing slates from Spain: Mormeau and Los Molinos Cardenes1, V., Cnudde1, V., Cnudde1, J.P. 1 Department of Geology and Soil Science, Ghent University, Krijgslaan 281, S8, 9000 Ghent, Belgium. The world's major roofing slate outcrops are found in the NW of Spain, in the Ordovician terrains of the domain of the Truchas Syncline. In this remote area, slate was quarried since ancient times for the use of the inhabitants of the region. Half of a century ago, an industrialization process took place in this area, which began to produce high quality roofing slate for many buildings from Japan to the USA, and especially in Europe. Since then, Spanish slate roofing has been widely used for new buildings and also for restoration of historical buildings. This work revises the occurrence and characteristics of the two most representative grey slate varieties from the Truchas Syncline, Mormeau, a fine-grained slate, and Los Molinos, also a grey slate with a slightly coarser grain. Both slates have a very similar aspect, but Mormeau slate have some iron sulphides on its composition that sometimes forms oxidation spots. Mormeau beds are found at the Middle-Upper Ordovician age Casaio Formation, while Los Molinos beds are located at the Rozadais Formation, of age Upper Ordovician, defined as formation just for the Truchas Syncline domain. Both slates have a high degree of homogeneity on their constructive characteristics, with a typical composition of quartz, mica and chlorites, and a metamorphic degree corresponding to the green schists facies. This work revises the history and characteristics of both slates, that can be considered as lithotypes that can be used as a reference during the prospection of new slate outcrops worldwide. The presented varieties of slate are proposed for their inclusion as Global Heritage Stones.

  20. A modelling study of long term green roof retention performance.

    Science.gov (United States)

    Stovin, Virginia; Poë, Simon; Berretta, Christian

    2013-12-15

    This paper outlines the development of a conceptual hydrological flux model for the long term continuous simulation of runoff and drought risk for green roof systems. A green roof's retention capacity depends upon its physical configuration, but it is also strongly influenced by local climatic controls, including the rainfall characteristics and the restoration of retention capacity associated with evapotranspiration during dry weather periods. The model includes a function that links evapotranspiration rates to substrate moisture content, and is validated against observed runoff data. The model's application to typical extensive green roof configurations is demonstrated with reference to four UK locations characterised by contrasting climatic regimes, using 30-year rainfall time-series inputs at hourly simulation time steps. It is shown that retention performance is dependent upon local climatic conditions. Volumetric retention ranges from 0.19 (cool, wet climate) to 0.59 (warm, dry climate). Per event retention is also considered, and it is demonstrated that retention performance decreases significantly when high return period events are considered in isolation. For example, in Sheffield the median per-event retention is 1.00 (many small events), but the median retention for events exceeding a 1 in 1 yr return period threshold is only 0.10. The simulation tool also provides useful information about the likelihood of drought periods, for which irrigation may be required. A sensitivity study suggests that green roofs with reduced moisture-holding capacity and/or low evapotranspiration rates will tend to offer reduced levels of retention, whilst high moisture-holding capacity and low evapotranspiration rates offer the strongest drought resistance.

  1. Models for acoustical properties of green roof materials

    OpenAIRE

    2011-01-01

    To predict the acoustical effects of green roof structures it is necessary to be able to model the acoustical properties of their materials including gravel. For time domain calculations it is convenient to use the phenomenological model due to Zwikker and Kosten. However this phenomenological model is related to a low frequency/high flow resistivity approximation of more ‘exact’ identical pore models. The results of fitting predictions to short range level difference data and to impedance da...

  2. The Transitivity Analysis of A Woman on a Roof

    Institute of Scientific and Technical Information of China (English)

    庞亚飞

    2012-01-01

      From the perspective of the transitivity theory, this dissertation aims to analyze feminist ideas in Doris Lessing’ s novel A Woman on a Roof. The analysis triumphantly proves that the transitivity system in SFG is an effective method in understand⁃ing author’ s feminist ideas. It is strongly hoped that this attempt will provide some valuable experience for better appreciating of other English novels.

  3. The Tajik People: Crown on the Roof of the World

    Institute of Scientific and Technical Information of China (English)

    GuBingshu

    2004-01-01

    The Tajiks reside in relative isolation in the snow-capped Pamir Mountain range of West China near the borders of Afghanistan, Pakistan and Russia. The Pamir mountains, known as the “roof of the world”, surround this specially designated Tajik district in three directions, and a desert borders the region on the fourth. The largest concentration of Tajik people live on the edge of Tashkorgan,

  4. PV on existing roofs. Experiences of sixty households

    Energy Technology Data Exchange (ETDEWEB)

    Kaan, H.F.; Van Dijk, A.L.; Van Leeuwen, M. [ECN Renewable Energy in the Built Environment DEGO, Petten (Netherlands)

    2001-05-01

    In order to stimulate the use of PV (photovoltaic energy) in the Netherlands, the Dutch government offers a subsidy of 3.40 Euro per Watt peak installed after January 2001. It is hoped that this will facilitate the market for PV systems. The newly to be build houses form a substantial potential as PV carriers, but the existing housing stock is much larger. PV on existing houses has been promoted for several years now in the Netherlands, amongst others by utilities, PV manufacturers and the environmental organization Greenpeace. The new subsidy scheme will undoubtedly have a large impact on the PV demand for existing houses. However, it is doubtful whether the technology is mature enough to meet a large scale demand. In order to learn from experiences with small scale PV systems on roofs of existing houses, the Energy research Centre of the Netherlands (ECN) has set up a research project in which participating employees give access to the roofs of their houses to install PV systems. Fifty-nine ECN employees entered for participation in this project. This group provides a random selection of roofs, so that many different types of roof integration can be examined. Subjects included in the project investigations are: constructional aspects, yield and reliability of systems, institutional aspects such as getting building permits, aesthetics, behavioural aspects. The project was set up in 2000. In April 2001, the installation had been monitored and evaluated. Also the preparatory and initial findings and experiences of project participants have been registered through a questionnaire. The yield of the modules is registered by the participants.

  5. Statistical analysis of the metrological properties of float glass

    Science.gov (United States)

    Yates, Brian W.; Duffy, Alan M.

    2008-08-01

    The radius of curvature, slope error, surface roughness and associated height distribution and power spectral density of uncoated commercial float glass samples have been measured in our Canadian Light Source Optical Metrology Facility, using our Micromap-570 surface profiler and long trace profilometer. The statistical differences in these parameters have been investigated between the tin and air sides of float glass. The effect of soaking the float glass in sulfuric acid to try to dissolve the tin contamination has also been investigated, and untreated and post-treatment surface roughness measurements compared. We report the results of our studies on these float glass samples.

  6. FORMULATION AND EVALUATION OF FLOATING TABLETS OF NORFLOXACIN

    Directory of Open Access Journals (Sweden)

    Ms. Jyoti Rathore

    2015-01-01

    Full Text Available The oral route is considered as the most promising route of drug delivery. Several approaches have been attempted in the preparation of gastro-retentive drug delivery systems. These include floating systems, swell able and expandable systems, high density systems, bioadhesive systems, altered shape systems, gel forming solution or suspension systems and sachet systems. Various approaches have been followed to encourage gastric retention of an oral dosage form. Floating systems have low bul density so that they can float on the gastric juice in the stomach. The problem arises when the stomach is completely emptied of gastric fluid. In such a situation, there is nothing to float on.

  7. Herbal carrier-based floating microparticles of diltiazem ...

    African Journals Online (AJOL)

    Various physicochemical properties of the floating microspheres were characterized, including ... Keywords: Diltiazem, Cardiac disease, Psyllium husk, Sodium alginate, Microsphere, Microparticle,. Controlled ..... solvent removal methods.

  8. Influence of artificial ecological floating beds on river hydraulic characteristics

    Institute of Scientific and Technical Information of China (English)

    饶磊; 钱进; 敖燕辉

    2014-01-01

    The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities ( v=0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s), floating bed coverage rates (20%, 40%, 60%) and arrangement positions away from the channel wall ( D=0 m, 0.1 m, 0.2 m). The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value (ARWLV) increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition (v³0.2 m/s) .

  9. Life, death, and resurrection on a green roof in Toronto

    Energy Technology Data Exchange (ETDEWEB)

    McGlade, T. [Perennial Gardens Corp., Toronto, ON (Canada)

    2004-07-01

    The Sears warehouse building in Toronto was constructed in 1910 and has been converted to a 400 unit loft condominium. Perennial Gardens Corporation was hired to landscape a rooftop garden on the huge open roof area to provide a place for residents to barbecue and relax. The process began with engineers placing the venting for the drains directly into the planting beds and addressing roof drain and sloping issues. There were many physical aspects which caused a variety of problems with this project, namely high wind velocity with a swirling effect which meant that all trees had to be tripod staked; soil erosion due to the wind; the plants which were mostly plugs or 4 inch pots contained soil which was not compatible with the sopraflor used through the rooftop and a major problem with dogs using the rooftop area. This landscape project demonstrated that not all perennials are suited for a green roof. The original planting list was provided along with problems encountered. 5 figs.

  10. Innovative Ballasted Flat Roof Solar PV Racking System

    Energy Technology Data Exchange (ETDEWEB)

    Peek, Richard T. [Cascade Engineering, Grand Rapids, MI (United States)

    2014-12-15

    The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.

  11. Suspended solids in and turbidity of runoff from green roofs.

    Science.gov (United States)

    Morgan, Susan; Alyaseri, Isam; Retzlaff, William

    2011-01-01

    Green roof technology is used to reduce the quantity of stormwater runoff, but questions remain regarding its impact on quality. This study analyzed the total suspended solids (TSS) in and the turbidity of runoff from green roof growth media mixed with composted pine bark in an indoor pot study. The results showed that there were elevated levels of TSS and turbidity in the runoff that decreased over time for all growth media. Both TSS and turbidity are affected by the type of growth media. Lava and haydite had higher mean TSS and mean turbidity than arkalyte and bottom ash. Vegetation reduced the mean turbidity and mean TSS of the first flush by an average of 53% and 63%, respectively, but generally had no statistically significant effect thereafter. The results indicate that the media, rather than the vegetation, has a greater effect on TSS and turbidity in the runoff In areas with stringent water quality regulations for stormwater runoff from developed sites, media selection may be an important consideration. It may also be necessary in these regions to ensure that the roof is planted prior to receiving rainfall to minimize the first flush effect and that any irrigation does not result in runoff.

  12. Standard tests for the characterization of roofing slate pathologies

    Directory of Open Access Journals (Sweden)

    Cárdenes, V.

    2012-06-01

    Full Text Available The pathologies formed in slate roofs are mainly due to the presence of potentially unstable minerals (iron sulfides, carbonates and organic matter. These minerals may become altered by the effect of environmental agents, once the slate roof is finished. The pathologies are mainly associated with oxidation and gypsification processes of the cited mineral phases. In this work, the potential pathologies of several Spanish roofing slates are identified, using the tests defined in the European Norms EN 12326:2005, 14147:2004 and 11597:2007.

    Las patologías que se originan en pizarra para cubiertas son debidas fundamentalmente a la presencia de materiales alterables (sulfuros de hierro, carbonatos y materia orgánica. Estos minerales pueden llegar a alterarse por efecto de los agentes medioambientales, una vez que la pizarra es puesta en obra. Las patologías están principalmente asociadas a procesos de oxidación y yesificación de las citadas fases minerales. En este trabajo se determinan las patologías potenciales de varias pizarras para cubiertas españolas, utilizando los ensayos definidos en las normas UNE-EN 12326:2005, 14147:2004 y 11597:2007.

  13. A generic hydrological model for a green roof drainage layer.

    Science.gov (United States)

    Vesuviano, Gianni; Stovin, Virginia

    2013-01-01

    A rainfall simulator of length 5 m and width 1 m was used to supply constant intensity and largely spatially uniform water inflow events to 100 different configurations of commercially available green roof drainage layer and protection mat. The runoff from each inflow event was collected and sampled at one-second intervals. Time-series runoff responses were subsequently produced for each of the tested configurations, using the average response of three repeat tests. Runoff models, based on storage routing (dS/dt = I-Q) and a power-law relationship between storage and runoff (Q = kS(n)), and incorporating a delay parameter, were created. The parameters k, n and delay were optimized to best fit each of the runoff responses individually. The range and pattern of optimized parameter values was analysed with respect to roof and event configuration. An analysis was performed to determine the sensitivity of the shape of the runoff profile to changes in parameter values. There appears to be potential to consolidate values of n by roof slope and drainage component material.

  14. Study of water infiltration in a lightweight green roof substrate

    Science.gov (United States)

    Tomankova, Klara; Holeckova, Martina; Jelinkova, Vladimira; Snehota, Michal

    2015-04-01

    Green roofs have a positive impact on the environment (e.g. improving microclimate and air quality in cities, reducing solar absorbance and storm water). A laboratory infiltration experiment was conducted on the narrow flume serving as 2D vertical model of a green roof. The lightweight Optigreen substrate Type M was used (depth of 20 cm). The front wall of the flume was transparent and inspected by digital camera. The experiment was designed to measure pressure head, volumetric water content and calculate water retention in the substrate. Experiment comprised three artificial rainfall intensities with different values of initial water content of the substrate. The experimental results confirmed that green roofs have the ability to retain rainwater and thus have a beneficial effect on reducing runoff. In the experiment with the artificial 10 minutes rainfall event (total precipitation of 29 mm), the air dry substrate retained 95.9 % of precipitation. On the other hand for moist initial condition 4.2 % of precipitations amount was captured in the substrate. Additionally, the analysis of images taken during the experiment confirmed preferential flow and uneven advancement of the wetting front. The research was realized as a part of the University Centre for Energy Efficient Buildings supported by the EU and with financial support from the Czech Science Foundation under project number 14-10455P.

  15. Taphonomic and sedimentologic characterization of roof-shale floras

    Energy Technology Data Exchange (ETDEWEB)

    Gastaldo, R.A.; Pfefferkorn, H.W.; DiMichele, W.A. [Auburn University, Auburn, IL (United States). Dept. of Geology

    1995-12-31

    Roof-shale floras have been a major source of data for the understanding of Carboniferous vegetation. Early debate on their origin centered around the question of whether these megafloral assemblages are autochthonous or allochthonous. In these discussions, the sedimentological context in which the preserved fossil assemblage (taphoflora) occurred was largely ignored. W.C. Darrah saw the complexity of these issues, presented helpful starting points for further investigations, and influenced the thinking of the next generation. This chapter characterizes the sedimentological and taphonomic features of a spectrum of roof-shale floras. There are three levels at which the preservation of plant parts can be viewed: (1) early taphonomic processes and earliest diagenesis can destroy or preserve plant parts in a given clastic depositional setting; (2) those plant parts that are preserved can be autochthonous, parautochthonour, or allochthonous in relationship to their original place of growth; (3) with respect to a peat layer (coal bed), the overlying clastic material can be deposited in a continuous transition, after a short temporal break (discontinuity), or after a significant hiatus of time. Characterization of roof-shale floras must take into consideration the sedimentological interpretation of the associated lithologies, the stratigraphic sequence, and the taphonomic processes involved in their formation. Characterization is essential before such floras can be used in higher-level interpretations, such as paleoecological reconstructions. 72 refs., 3 figs., 3 tabs.

  16. Operation of roof pond systems, considering its advantages and disadvantages

    Energy Technology Data Exchange (ETDEWEB)

    Noohi, Samira; Rezaei, Davood [Faculty of engineering, Zanjan University (Iran, Islamic Republic of)], email: noohi.sam@gmail.com, email: d_rezaei@znu.ac.ir

    2011-07-01

    With the coming shortage of fossil fuels it is important to develop energy efficient buildings to reduce both energy consumption and pollution at the same time. The roof pond system is a passive solar system which gathers heat from the sun and can distribute it to the living space to cool it or heat it by changing the operating cycle. Although not recent, this method has not been widely implemented due to certain limitations and the aim of this paper is to assess the different advantages and disadvantages of this system over other passive solar heating systems. This study showed that a roof pond has a low impact on the building, provides controllable energy delivery and variations in indoor temperature are low; however it requires an active solar system as a backup and vegetation can limit sunlight penetration. This study highlighted that the efficiency of the roof system pond depends on climate conditions and that it is best suited to lower latitude and low humidity areas.

  17. Innovative Ballasted Flat Roof Solar PV Racking System

    Energy Technology Data Exchange (ETDEWEB)

    Peek, Richard T.

    2015-01-23

    The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.

  18. Retrofitted green roofs and walls and improvements in thermal comfort

    Science.gov (United States)

    Feitosa, Renato Castiglia; Wilkinson, Sara

    2017-06-01

    Increased urbanization has led to a worsening in the quality of life for many people living in large cities in respect of the urban heat island effect and increases of indoor temperatures in housing and other buildings. A solution may be to retrofit existing environments to their former conditions, with a combination of green infrastructures applied to existing walls and rooftops. Retrofitted green roofs may attenuate housing temperature. However, with tall buildings, facade areas are much larger compared to rooftop areas, the role of green walls in mitigating extreme temperatures is more pronounced. Thus, the combination of green roofs and green walls is expected to promote a better thermal performance in the building envelope. For this purpose, a modular vegetated system is adopted for covering both walls and rooftops. Rather than temperature itself, the heat index, which comprises the combined effect of temperature and relative humidity is used in the evaluation of thermal comfort in small scale experiments performed in Sydney - Australia, where identical timber framed structures prototypes (vegetated and non-vegetated) are compared. The results have shown a different understanding of thermal comfort improvement regarding heat index rather than temperature itself. The combination of green roof and walls has a valid role to play in heat index attenuation.

  19. ASH External Web Portal (External Portal) -

    Data.gov (United States)

    Department of Transportation — The ASH External Web Portal is a web-based portal that provides single sign-on functionality, making the web portal a single location from which to be authenticated...

  20. Estimation of evaporative losses during storage of crude oil and petroleum products

    Directory of Open Access Journals (Sweden)

    Mihajlović Marina A.

    2013-01-01

    Full Text Available Storage of crude oil and petroleum products inevitably leads to evaporative losses. Those losses are important for the industrial plants mass balances, as well as for the environmental protection. In this paper, estimation of evaporative losses was performed using software program TANKS 409d which was developed by the Agency for Environmental Protection of the United States - US EPA. Emissions were estimated for the following types of storage tanks: fixed conical roof tank, fixed dome roof tank, external floating roof tank, internal floating roof tank and domed external floating roof tank. Obtained results show quantities of evaporated losses per tone of stored liquid. Crude oil fixed roof storage tank losses are cca 0.5 kg per tone of crude oil. For floating roof, crude oil losses are 0.001 kg/t. Fuel oil (diesel fuel and heating oil have the smallest evaporation losses, which are in order of magnitude 10-3 kg/tone. Liquids with higher Reid Vapour Pressure have very high evaporative losses for tanks with fixed roof, up to 2.07 kg/tone. In case of external floating roof tank, losses are 0.32 kg/tone. The smallest losses are for internal floating roof tank and domed external floating roof tank: 0.072 and 0.044, respectively. Finally, it can be concluded that the liquid with low volatility of low BTEX amount can be stored in tanks with fixed roof. In this case, the prevailing economic aspect, because the total amount of evaporative loss does not significantly affect the environment. On the other hand, storage of volatile derivatives with high levels of BTEX is not justified from the economic point of view or from the standpoint of the environment protection.