Weatherability Studies on External Insulation Thermal System of Expanded Polystyrene Board,Polystyrene Granule and Polyurethane Foam

Atmospheric exposure tests including two experimental stages of high temperature-spraying water cycle and heating-refrigeration cycle were carried out on three currently used ETIS of expanded polystyrene（EPS） board,polystyrene granule mortar and polyurethane foam in order to study the weatherablility of external thermal insulation system（ETIS）.The change rules of adhesive strength were hereby studied at different time period of atmospheric exposure tests.The experimental results show that the adhesive strength of three kinds of ETIS changes a little during high temperature-spraying water cycle,but the adhesive strength of ETIS with EPS board decreases significantly after heating-refrigeration cycle.The lowering rate of adhesive strength with painting finishes is obviously faster than that of tile finishes for ETIS of EPS board during heating-refrigeration cycle.The weatherability of ETIS with EPS board is worse than the other two,and ETIS of polystyrene granule mortar and polyurethane foam are more suitable than ETIS of EPS board in cold area.

Impact of light-weight external thermal insulation materials on building surrounding thermal environment in summer

The method for calculating wall surface heat storage coefficient was introduced,and the coefficients of several common walls with light-weight external thermal insulation materials and the traditional solid clay brick wall were calculated.In order to study the impact of light-weight external thermal insulation materials,a contrasting experiment was carried out between an external insulated room and an uninsulated room in August,2010,in Chongqing,China.The result shows that outside surface heat storage coefficient of the insulated wall is much less than that of the traditional wall.However,during sunny time,the surface temperature of external walls of the insulated room is obviously higher than that of the uninsulated room.In different orientations,due to different amounts of solar radiation and being irradiated in different time,the contrasting temperature difference(CTD) appears different regularity.In a word,using light-weight external thermal insulation materials has a negative impact on building surrounding thermal environment and people's health.Finally,some suggestions on how to eliminate the impact,such as improving the surface condition of the building envelop,and plating vertical greening,are put forward.

THERMAL EFFECTS OF BUILDING′S EXTERNAL SURFACES IN CITY——Characteristics of Heat Flux into and out of External Wall Surfaces

This study examined the thermal effects of building′s external wall surfaces, using observational data of spatial-temporal distribution of surface temperature, air temperature, and heat flux into and out of external surface. Results indicate that external wall surface temperature and nearby air temperature vary with the change of orientation, height and season. In general, the external wall surface temperature is lower near the ground, and is higher near the roof, than nearby air temperature. But north wall surface temperature is mostly lower than nearby air temperature at the same height; south wall surface temperature during the daytime in December, and west wall surface temperature all day in August, is respectively higher than nearby air temperature. The heat fluxes into and out of external wall surfaces show the differences that exist in the various orientations, heights and seasons. In December, south wall surface at the lower sites emits heat and north wall surface at the higher sites absorbs heat. In April, all external wall surfaces, emit heat near the ground and absorb heat near the roof. In August, west wall surface all day emits heat, and other wall surfaces just show the commensurate behavior with that in April.

A STUDY ON THE CHARACTERISTICS OF INTERNAL ANDEXTERNAL WALL SURFACE TEMPERATUREIN THE URBAN AREA

Internal and external wall surface temperatures (Tws) in April, August and December in Kunming, a city in low latitude plateau, were investigated. Results showed that the Tws in April were of the highest among the three, followed by August and December. The Tws differences among walls with different orientation were higher in April and December when the weather tends to be sunny, and lower in August with more cloudy days in the time. In April and August, Tws of E-wall was the highest, followed by S- and N-wall. But in December Tws of S-wall might be sometimes higher than E one. Diurnal range of internal Tws was usually smaller than that of the external, with also a time lag for the occurrence of its maximum and minimum. The results can serve as a basis for further research on building microclimate and urban architecture designs. It also gives suggestions for similar studies in other areas.

External application of a Nocardia rubra cell wall skeleton in the treatment of diabetic foot ulcers

Diabetic foot ulcers are one of the most severe complications of diabetes that have imposed great financial and psychological burdens on diabetic patients.A Nocardia rubra cell wall skeleton(Nr-CWS)can be externally applied to accelerate wound healing.However,its clinical application has not yet been reported.Herein,we report two patients with diabetic foot ulcers treated with Nr-CWS.After wound debridement,the wound was covered with a sterile cotton ball infiltrated with an Nr-CWS that was diluted with 2.0 mL of saline.The covers were changed every two days until complete wound healing occurred.The two wounds healed after 3 and 12 weeks,respectively.This article aims to provide a new treatment for diabetic foot ulcers,with the hope that physicians may consider an Nr-CWS as a complementary method for the treatment of chronic wounds.

Passive cooling of porous tile used on external wall

The porous tiles under the dry and wet conditions were studied. The simplified mathematical model was put forward to simulate the procedure of moisture evaporating for the densely porous tile. The results show that the capability of passive cooling of the porous tile is more than 5 ℃ with moisture content of 30% in Yangtze river region. Through the comparison between the measuring and simulating data,it can be proved that the simplified math model can be fully used to the engineering application,which provides a reference to explore the thermal performance of other porous material.

Externalized conductors and insulation failure in Biotronik defibrillator leads: History repeating or a false alarm?

Conductor externalization and insulation failure are frequent complications with the recalled St. Jude Medical Riata implantable cardioverter-defibrillator(ICD) leads. Conductor externalization is a "unique" failure mechanism: Cables externalize through the insulation("inside-out" abrasion) and appear outside the lead body. Recently, single reports described a similar failure also for Biotronik leads. Moreover, some studies reported a high rate of electrical dysfunction(not only insulation failure) with Biotronik Linox leads and a reduced survival rate in comparison with the competitors. In this paper we describe the case of a patient with a Biotronik Kentrox ICD lead presenting with signs of insulation failure and conductor externalization at fluoroscopy. Due to the high risk of extraction we decided to implant a new lead, abandoning the damaged one; lead reimplant was uneventful. Subsequently, we review currently available literature about Biotronik Kentrox and Linox ICD lead failure and in particular externalized conductors. Some single-center studies and a nonprospective registry reported a survival rate between 88% and 91% at 5 years for Linox leads, significantly worse than that of other manufacturers. However, the preliminary results of two ongoing multicenter, prospective registries(GALAXY and CELESTIAL) showed 96% survival rate at 5 years after implant, well within industry standards. Ongoing data collection is needed to confirm longer-term performance of this family of ICD leads.

Numerical simulation on the seismic performance of retrofitted masonry walls based on the combined finite-discrete element method

Due to the long construction life,improper design methods,brittle material properties and poor construction techniques,most existing masonry structures do not perform well during earthquakes.The retrofitting method using an external steel-meshed mortar layer is widely used to retrofit existing masonry buildings.Assessing the seismic performance of masonry walls reinforced by an external steel-meshed mortar layer reasonably and effectively is a difficult subject in the research field of masonry structures.Based on the combined finite-discrete elements method,the numerical models of retrofitted brick walls with four different masonry mortar strengths by an external mortar layer are established.The shear strength of mortar and the contact between the retrofitted mortar layer and the brick blocks are discussed in detail.The failure patterns and load-displacement curves of the retrofitted brick walls were obtained by applying low cycle reciprocating loads to the numerical model,and the bearing capacity and the failure mechanism of the retrofitted walls were obtained by comparing the failure patterns,ultimate bearing capacity,deformability and other aspects with the tests.This study provides a basis for improving the seismic strengthening design method of masonry structures and helps to better assess the seismic performance of masonry structures after retrofitting.

Experimental study on axial compressive behaviors of prefabricated composite thermal insulation walls after single-side fire exposure

The axial bearing capacity of prefabricated composite walls composed of inner and outer concrete wythes,expandable polystyrene(EPS)boards and steel sleeve connectors is investigated.An experimental study on the axial bearing capacity of four prefabricated composite walls after fire treatment is carried out.Two of the prefabricated composite walls are normal-temperature specimens,and the others are treated with fire.The damage modes and crack development are observed,and the axial bearing capacity,lateral deformation of the specimens,and the concrete and reinforcing bar strain are tested.The results show that the ultimate bearing capacity of specimens after a fire is less than that of normal-temperature specimens;when the insulation board thicknesses are 40 mm and 60 mm,the decrease amplitudes are 20.8%and 16.8%,respectively.The maximum lateral deformation of specimens after a fire is greater than that of normal-temperature specimens,and under the same level of load,the lateral deformation increases as the insulation board thickness increases.Moreover,the strain values of the concrete and reinforcing bars of specimens after a fire are greater than those of normal-temperature specimens,and the strain values increase as the thickness of insulation board increases.

Finite Element Analysis of External Thermal Insulation Composite System:Thin Rendered Expanded Polystyrene Board

The finite element model of an external thermal composite insuiation system, thin rendered expanded polystyrene （ EPS ） board, was built with ANSYS 1.0, which had two forms： one with window and one without window. The finite element analysis results show that the EPS board had very good insulation capacity at both high or low temperature, stress concentration was produced in the center of wall and around window, and the maximum deformation was observed at the edge of board and the minimum deformation was in the center.

Advanced Deterioration Diagnosis Model for Building External Wall Tiles

In 1981 Taiwan entered a period of intense construction, meaning that today many buildings are more than 30 years old. Lack of maintenance has led to frequent safety incidents involving external walls. This study focuses on a deterioration diagnostic model for external wall tiles of aged buildings, using both stage 1 and stage 2 diagnostic methods. The visual test results are categorized based on impact on public safety, and renovation strategies are proposed. Stage 1 diagnosis mainly adopted the DER visual inspection deterioration assessment method. For enhance the accuracy, this research adopted the Infrared Thermal Imaging detection method to double confirm the visual inspection results. After producing an external wall tile Condition Indicator (CI). For stage 1 diagnostic results that fall in a gray area, stage 2 diagnosis was carried out using a tap tone test, followed by fast Fourier transform and pattern recognition to analyze the tapping results. Finally, the study provides a deterioration evaluation criteria for external wall tiles replacement recommendations and a standard operating procedure for deterioration diagnosis. The study also recommends directions for future amendment of regulations, and provides a basis of reference for the government in determining urban renewal, renovation and maintenance strategies.

Prevention and Control Measures for Vertical Spread of Fire along the External Wall of High-rise Buildings

In the analysis and research of few cases on the characteristics of vertical"burning"and spreading of fire in high-rise buildings in China and overseas,the mechanism of vertical spreading of fire along external wall is caused by hot pressing and wind pressure existing in high-rise buildings.The use of external wall combustible materials and near-window combustible items resulted in the formation of high temperature pyrotechnics and the burning of the external wall.Besides,due to the lack of fire-fighting measurements in high-rise building,it is recommended that the external wall of the high-rise building should be equipped with vertical fire-proof partitioning and non-combustible materials by setting up an automatic fire-fighting water curtain system along the vertical section of the external wall and above the indoor window.Therefore,the automatic sprinkler can be set up to prevent the fire from spreading vertically along the external wall of the building effectively.

CFD Simulations of Wind Effect on Net Solar Heat Gain of South Walls with Internal Insulation

Computational fluid dynamics( CFD) techniques are used to investigate effects of both wind direction and wind speed on net solar heat gain of south wall with internal insulation in winter.Results show that wind effect has a significant influence on the net solar heat gain,where the impact of wind direction is stronger than that of wind speed. For regions in lower reaches of the Yangtze River,difference of their average net solar heat gains( NSHGS) is about 20% due to various wind speeds and wind directions.Buildings in districts with a dominant wind direction of north achieve the highest solar energy utilization.

Suitability and Construction of Self-Insulation Walls in the Hot Summer and Cold Winter Zone of Southern Shaanxi

In this paper, the suitability and construction technology of self-insulation walls were studied under the specific climatic conditions and regional resources of Hanzhong and Ankang in the hot summer and cold winter zone of Southern Shaanxi. Through the calculation of heat transfer coefficient and thermal inertia index, combined with the specifications of the shale hollow brick and aerated concrete block of Hanzhong and Ankang in southern Shaanxi, the thermal performance and suitable thickness of the external wall using self-insulation materials that meet the Design Standard for Energy Efficiency of Residential Buildings(DBJ61-65-2011) in Shaanxi Province were obtained. The results showed that the self-insulation wall had technical suitability in the hot summer and cold winter zone. The research results provide not only a theoretical basis for the external wall insulation design of urban residential buildings in the hot summer and cold winter zone of southern Shaanxi, but also a reference for designers to carry out energy-saving design of external walls of residential buildings in other similar climate zones.

The Theoretically Studies and Field Testing of Self-Insulation Exterior Wall in the Hot Summer and Cold Winter Zone

The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation of the exterior?wall is a more feasible design to satisfy the energy efficiency of buildings in the?zone. However, the systematic research is urgently needed for the self-insulation of the exterior wall in the hot summer and cold winter zone of China. The paper tested the thermal performance of the common non-clay materials such as shale sintered hollow brick, sand autoclaved aerated concrete block, etc. by means of indoor experiments. The energy efficiency effect of the common materials was verified using dynamic calculation soft PKPM and several constitutions of exterior wall with different main bricks and insulation materials on the heat bridge were simulated, too. Besides, the tests of the thermal performance of exterior wall in real constructions were carried out to testify the practical effect of the recommended constitutions of exterior wall with different main bricks and insulation materials on the heat bridge. The conclusions are: the physical and thermal properties of the six non-clay wall material are better than the clay porous brick;the thermal performance of the non-clay brick can be improved obviously through the rational arrangement of the holes;shale sintered hollow brick after increasing the holes and rationalizing the hole arrangement and sand autoclaved aerated concrete block are recommended for buildings in the hot summer and cold winter area of China. The dynamic calculation results show that the thermal performances?of the non-clay materials are all satisfied with the energy efficiency;The heat transfer coefficient of the exterior wall with composition?③,?in which?the main wall was sand autoclaved aerated concrete block and the material on the heat bridge was sand autoclaved aerated concrete plate, is the smallest among the three recommended compositions.

模卡砌块组合保温墙体热工性能及其经济性分析

随着超低能耗建筑、近零能耗及零能耗建筑的发展,新型外墙围护结构引起广泛地研究和重视.模卡砌块作为一种新型外墙自保温技术,开始在上海、江苏等国内一些发达地区被试点和应用,但目前暂无相应规范指导,其热工性能及经济性仍缺乏系统性研究.文中以夏热冬冷地区某公共建筑为例,采用DeST能耗模拟软件,建立了传统外保温墙体、模卡砌块组合保温墙体三维分析模型,研究了膨胀聚苯板、岩棉板、聚氨酯板、挤塑聚苯板4种不同类型保温材料及6种不同厚度(30、50、70、90、110、130 mm)下模卡砌块组合保温墙体的热工性能.进一步,采用净现值法,对不同工况下的砌块组合保温墙体进行了经济性分析.研究表明:在相同外墙保温厚度下,聚氨酯板的保温效果最佳;不同保温材料厚度对应的净现值都呈现出先上升后下降的趋势,结合净现值和节能率,其最优厚度分别为70、70、40、60 mm,对应的节能率分别在达到我国建筑节能65%的标准上再降低7.08%、6.81%、5.1%、6.5%.

装配式日光温室柔性复合墙体性能测试与分析

为解决装配式日光温室柔性墙体蓄热能力不足的问题,该研究通过在墙体内侧附加蓄热层的方式,设计了一种集蓄热、保温和防水多功能于一体的装配式柔性复合墙体。首先,通过对多种材料进行综合性能评估,筛选出优质的表层材料和保温材料,将其复合制成柔性保温墙体;其次,将水、沙子、相变水凝胶(phase change hydrogel,PCH)作为蓄热层固定在柔性保温墙体内侧,从而形成柔性复合墙体;最后,在4个模型温室中分别对墙体进行性能测试,以未附加蓄热层的柔性保温墙体为对照(CK),分析试验墙体的蓄热和保温性能。单一墙体材料的性能测试结果表明,表层材料中镀铝编织布、黑色淋膜毡抗拉性能好且不透水,断裂强力分别为1.06、0.56 kN,断裂伸长率分别为30.99%、65.91%;保温材料中再生棉、太空棉和空气柱保温效果较好且使用成本低,热阻值分别为0.30、0.50、0.76(m^(2)·℃)/W。柔性复合墙体的性能测试结果表明,所有处理中5 kg/m^(2) PCH柔性复合墙体的蓄热和保温性能最佳,热阻值为2.50(m^(2)·℃)/W,单位面积累计吸热量与放热量分别为1.48、1.13 MJ/m^(2);在典型晴天和阴天条件下,该处理的夜间室内平均温度分别比CK提高了3.08、1.87℃。上述分析结果表明,通过在柔性保温墙体内侧附加相变蓄热层的方式,能够增强墙体的蓄热和保温性能。研究结果可为今后装配式日光温室柔性复合墙体设计及材料选择提供理论依据。

外挂墙板施工阶段碳排放的智能监测与优化

建筑行业的温室气体过量排放逐渐引起了人们的关注,且其施工阶段往往面临成本超标、工期延长和碳排放失控等问题,因此,建筑施工阶段碳排放的监测与多目标优化问题成为目前研究重点。为了有效解决上述问题,从物理层、计算层和交互层三部分提出了监测优化系统的框架;以Revit为二次开发平台、利用MySQL建立数据库,搭建了碳排放智能监测与优化平台;以外挂墙板构件施工过程为例,运用融入柔性理念的遗传算法寻找出使得“成本工期碳排放”综合目标最适合项目特征的工序执行模式组合及最优解。研究为装配式建筑施工阶段的碳排放监测与优化提供了一套科学、高效的集成化管理技术。

外墙保温一体化系统黏结性能影响因素及机理研究

外墙保温系统是建筑节能的主要路径之一,建筑外墙保温一体化系统是目前上海市主流应用的外墙保温系统。基于外墙保温一体化系统应用现状,分析了不同类型界面处理剂,不同施工环境条件和拉拔尺寸等因素对外墙保温一体化系统黏结性能的影响规律。研究成果对促进外墙保温一体化系统性能提升、保障建筑外立面安全具有指导意义。

长时间工作固体火箭发动机长尾喷管外绝热装置设计

固体火箭发动机长尾喷管周围一般安装有电子仪器,故而对喷管壳体表面温度有严格的限制。对于某长时间工作的发动机,为满足喷管壳体表面温度要求,同时降低消极质量,设计了一种新型双腔外绝热装置,以实现在较小的消极质量下具有较好的绝热性能。对该绝热装置进行了内流场及传热计算分析,而后进行了绝热结构优化及试验验证。结果表明:该双腔外绝热装置可以将长时间工作固体火箭发动机长尾喷管外壁温度从483℃降低至103℃,降低约78.7%;而采用同等材料同等质量的常规外防护装置只能从483℃降低至227℃,降低约53.0%;而要达到相同的防护效果,同等材料常规外防护装置的质量将增加约160%。双腔外绝热装置中段及尾端处温度随时间变化趋势与实测结果吻合较好,有望应用于其他长时间工作发动机。