Analysis and design program for series piping systems

Computer program aids in the analysis and design of series piping systems. Reference: B. K. Hodge, Analysis and Design Program for Series Piping Systems,Fire Technology, Vol. 21, No. 4, November 1985, p. 310.(Reprinted with permision fromHeating/Piping/Air Conditioning, April 1985, pp. 85–89. Penton — IPC, Rheinhold Publishing Division.)     

几种地下水热泵系统的水路连接方式

比较了空调水系统与生活热水水系统完全分开、相关联且井水系统串级、完全分开但设有电动三通阀、生活热水采用热回收型水源热泵机组这四种水路连接方式，认为后两者更加合理和节能。     

Reliability of piping systems and effect of inspection methods

The reliability of a piping system (or a cylindrical vessel) is determined by a statistical failure process. The risk of failure at any period of service life is evaluated and the effects of various inspection methods on the total risk are examined. The influence of different parameters, such as quality control and relative detectable crack size, on the total reliability are studied.The results of this study point out that a program of periodic inspection at appropriate intervals may be as efficient as that of a continuous inspection. There is a definite advantage in detecting small relative flaw sizes in the initial periodic inspection. The interval between subsequent inspections can thus be increased.     

北美流行的散热器及供暖设计方案

介绍了美国，加拿大流行的供暖设计方案及其所用的散热器，对比了国内现行的散热器在高层建筑中常用的垂直串联管系统，并提出了供国内思考参考的意见。     

Thermal behavior of building walls in summer: Comparison of available analytical methods and experimental results for a case study

There is a wide variety of thermal analyses that can be used to characterize the thermal behavior of a wall under certain outdoor conditions. The selection of a particular wall configuration for a building project involves not only the outdoor climate, but also the whole building characteristics, orientation, percentage of glazed areas, occupation periods, lifestyles, etc. In this paper we apply common available methods for wall thermal analysis to two particular wall types, a massive brick wall and an insulated brick wall, in order to compare the information given by each method and to evaluate how these methods can help in the selection of a certain type of wall. The studied methods include the estimation of the wall time lag and decrement factor, the harmonically heated slab model, the Athanassouli’s method, and numerical simulations. The study was performed for the walls of a residence for university students and it was built in La Pampa (Argentina). Once the building was finished, the transient thermal behavior of two walls was monitored during one summer week. The experimental results are presented and the fitting with the thermal behavior predicted by each method is discussed. The thermal comfort indicators PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for two flats, at ground floor and first floor respectively.     

适合热计量的室外供热系统控制方式与分析

针对可热计量的两种室内供热系统,在计算分析的基础上认为,对于采用集中式热力站的系统,在用户入口处,单管跨越式系统应加流量限制器,双管系统应设差压控制器;对于采用分散式热力站的供热系统,单管跨越式系统可不设流量限制器,双管系统二次侧宜采用循环水泵变频调速控制,不宜加差压控制器。     

供暖与空调水系统金属管道的选择

供暖与空调水系统应考虑管道的承压,以确保整个水系统设计的经济性与运行的安全可靠性。介绍了金属管道在供暖空调水系统中的正确选择方法。     

Comfort and energy conservation: A need for reconciliation?

This paper is focused on background issues which currently underlie attempts to reconcile comfort with reduced consumption of fuels in buildings in Britain. Two specific topics are considered; first, developments which have taken place in environmental design and, second, those which have occurred in comfort research in this country over the past thirty years. Developments in both these fields are presented as having contributed to making the idea of habitable spaces in buildings in Britain synonymous with the notion of consuming finite fossil fuels. Physiologically-grounded, orthodox comfort theory is questioned as an adequate basis for understanding how people judge internal environments in buildings they occupy since social issues, concerned with what constitutes an acceptable environment, are also identified as significant. environment, are also identified as significant.     

区域供冷系统二次管网的优化设计

分析了区域供冷系统二次管网的优化设计方法,建立了管径非连续变化的区域供冷系统二次管网的优化设计模型,并提出了求解方法。在对某区域供冷系统二次管网工程实例进行优化的基础上,进一步分析了传统设计与优化设计方法下二次管网经济性的差异。结果表明,优化设计方法通过权衡二次管网的初投资与二次泵的运行费用,使得二次管网在整个寿命周期内经济性较优;相对于经济流速分别取0.8,1.8,2.5m/s时假设流速法的计算结果,采用优化设计方法可分别节省寿命周期费用14.3%,16.2%,39.9%。     

The effect of wind suction on flat roofs: An experimental and analytical study of mechanically fastened waterproofing systems

Presently, mechanically fastened waterproofing systems are widely used in large roofs, mostly in industrial and commercial buildings. This paper presents a study of this constructive system that included the analysis of the mechanisms of response to wind loads and the effects of the different components on the system’s wind resistance. Wind up lift tests were performed on mechanically fastened waterproofing systems, according to the guideline for European technical approval (ETAG 006), in order to evaluate the influence of both the thermal insulation thickness (from 40 mm to 100 mm) and the characteristics of the atactic polypropylene (APP) modified bitumen waterproofing membranes (different constitutions, single/double layer) on the resistance to wind up lift. All tested mock-ups failed due to peeling of the overlapping membranes. Within the range of analysed systems, the thickness of the thermal insulation and the characteristics of the waterproofing membranes did not present a noticeable effect on the resistance of the tested mock-ups. Results obtained in the experimental tests were compared to other results gathered from European technical approvals. Additionally, results were used to define the field of application of the tested systems to a National level, based on the wind loads defined in the Portuguese code and the design procedure presented in Eurocode 1 and ETAG 006.     

适用于混沌密钥分发的新误码协调方法

对于现有的密钥分发中的误码协调方法的复杂性和多次传输的问题,使用倒三角类坐标定位法来解决。将所得裸钥放置于下三角矩阵中,三边分别进行奇偶比较并互相传输计算结果,以达到定位错误比特位的目的。使用互注入光反馈激光器产生相关性高的混沌态来提取裸钥,通过该协调方法,最终可以达到10-8~10-10量级的误码率。通过该方法可以简单、有效地删除裸钥中的误码,满足现实通信对误码率的容忍度。     

A new model based on experimental results for the thermal characterization of bricks

The development of fast and reliable protocols to determine the characteristics of building materials is of importance in order to develop environmentally friendly houses with an efficient energy design. In this article heat flux evolution on different types of clay and concrete bricks has been studied using a guarded hot-plate. The studied bricks were purchased from local commercially available sources and included a solid face brick and a range of honeycombed and perforated bricks. From the data collected a new model to study heat flux is proposed. This model is based on the shape of the typical sigmoidal curves observed for the time dependent heat flux evolution. The model allows the calculation of the thermal resistance (R) and the heat flux in the steady-state (φ_∞). The model also calculates two new parameters, t_B and τ_B. t_B represents the time at which half φ_∞ is attained. This parameter (t_B) has additionally been found to be dependent on the thermal diffusivity and the geometric characteristics of the brick.     

Computational methods for accounting of structural uncertainties, applications to dynamic behavior prediction of piping systems

Computational probabilistic methods enable us to incorporate and propagate uncertainties in mechanical models. However, in some cases, classical methods, such as FORM/SORM methods and Monte-Carlo methods, can be computationally expensive or inaccurate. An efficient importance sampling method is then suggested to yield sufficiently accurate results with acceptable computational cost in an industrial context. The method is an importance sampling method based on a second order asymptotic approximation combined with the HyperCube Latin method. A clustering method is used to solve the global optimization problem which arises to find the points of maximum likelihood. The efficiency of the method compared to classical methods is illustrated with several examples. Considerable reduction of the statistical error of the estimated failure probability can be achieved. The interest of the method is assured provided the points of local maximum likelihood are not too numerous and uniformly distributed. The paper presents two vibratory test cases, the second one is an industrial piping system.     

冷却塔的选型和配管设计

举例介绍了冷却塔的选型和配管设计中应该注意的问题。     

变流量二次泵系统管网特性研究

计算分析了目前常用的供回水管压差控制、末端压差控制方式下二次泵变流量系统管网特性的变化,发现用户部分负荷时,采用供回水管压差控制的系统中,末端一般处于过流状态;采用末端压差控制的系统,末端一般处于欠流状态.建议在设计时可适当增大末端用户干管的管径,以减小沿程阻力损失,提高系统的稳定性.     

A new analytical solution for the displacement of fully grouted rock bolt in rock joints and experimental and numerical verifications

This study proposes a new analytical solution to predict displacement of a fully grouted rock bolt intersected by single rock joint. The main characteristics of the analytical model, consider the bolt profile and joint movement under pull test condition. The anchorage capacity of fully grouted bolts has been studied for many years; however, the bolt profile and its effect on bolt shear resistance are poorly understood. Investigations of load transfer between the bolt and grout indicate that the bolt profile shape and spacing play an important role in improving the shear strength between the bolt and the surrounding strata. Rock displacement is a sum of elastic part and a jump part due to the presence of joints planes. The performance of the proposed analytical model is validated by experimental method and comparison with numerical modeling. The results showed that there is a promising agreement between analytical and numerical methods. Studies indicate that the displacement rate between the bolt and the rock declines exponentially. Which is dependent on the bolt characteristics such as: rib height, rib spacing, rib width and thickness grout, material and joint properties.     

Control of seismic response of piping systems and components in power plants by base isolation

Standard approaches to the aseismic design of piping systems and components for power plants — such as the floor spectrum method — are costly and neglect equipment-structure interaction. Such interaction has recently been shown to be severe when the natural frequency of a component is close or equal to one of the natural frequencies of the primary structure — a situation referred to as tuning and one almost certain to occur in a large structural system. A base isolation system is described that has been demonstrated to reduce dramatically the accelerations induced in structures under earthquake motion. A series of further experiments is described in the paper; this experimental work demonstrates that the response of equipment in structures so isolated is also greatly reduced. Thus, sensitive internal equipment can be protected directly from seismic attack; interaction need not to be considered and inelastic analyses need not be performed during the design process. Due to rigid body action of the primary system above the base isolation system, multiple support response spectra design methods are not needed. It is anticipated that the use of base isolation will reduce the cost of the design and construction of power plant components, piping systems, and structures.     

Comparison of point cloud data and 3D CAD data for on-site dimensional inspection of industrial plant piping systems

Inspection is vital in industrial plant construction and management. However, traditional inspection methods that rely on human involvement and paper documentation are becoming untenable as modern industrial plants are becoming larger and more complex than legacy facilities. Hence, an efficient and robust method is required to support the inspection of modern industrial plants. In this paper, an improved technique relying on terrestrial laser scanning (TLS) for data acquisition and normal-based region growing and efficient random sample consensus (RANSAC) for point cloud data processing is proposed for the on-site dimensional inspection of the piping systems of an industrial plant. Consequently, the as-built condition of the plant is assessed via a distance-based deviation analysis and a comparison of geometric parameters between the as-designed and as-built models. The method is validated using a dataset acquired from a compartment of a ship has verified the robustness and reliability of the proposed approach.     

Lead fragments in tissues from wild birds: A cause of misleading analytical results

Seriously damaged eider ducks (Somateria mollissima) and long-tailed ducks (Clangula hyemalis) were shot in connection with an oil spill in 1974. Liver and kidney tissues were analyzed for environmental pollutants and lead analysis gave irreproducible results. By means of X-ray photographs, X-ray-dense particles could be observed in the tissues.The foreign particles were extracted by dissolution of the organ tissues in Soluene-350 (Packard Instruments Co. Inc) and then washed with toluene. The insoluble particles consisted of lead and bone splinters of varying size. The form of the former ranged from irregular fragments to dust, and arose by disruption of lead pellets upon collision with bone tissue.Birds shot with lead pellets should not be used for lead determination unless careful X-ray investigations are made prior to the chemical analysis. Determinations should be made on at least two different samples of the tissue examined.