Transfer of Ultrafine Particles and Air in Multi-storey Buildings

An emerging issue in Denmark is passive smoking in residential buildings where non-smokers are exposed to smoke from their neighbours. There are various ways that smoke is transferred from one flat to another. The air transfer rate between two flats in a multi-storey building depends on its construction, tightness and age. This paper presents results of a study on the transfer of ultrafine particles and tracer gas in an older multi-storey building in Copenhagen. The aim of the study was to quantify the transfer ofultrafine particles and gases from one flat to another fiat before and after sealing the floor. A new floor-sealing method was applied to seal the floor between the two flats. The sealing method was developed by a firm specialising in sealing. Indoor ultrafine particle concentrations and tracer gas were measured continuously in the two fiats during the measuring periods. In the unoccupied fiat, the gas source was N20 and the particle source was burning cigarettes. Reduction of the concentration of ultrafine particles and tracer gas by sealing the floor with polyethylene and joint filler made of bitumen was studied. It was evaluated how the sealing performed with regard to decreasing the amount of ultrafine particles and a tracer gas transferred between two fiats separated by a floor. When the floor between the flats was not sealed, the results showed that about 4% of the ultraflne particles and 14% of the tracer gas were transferred. After sealing, the amount transferred was reduced to 1.6% and 5%, respectively.     

Sensitivity Study of Design Parameters of a Railway Route under Vertical Deformations

Studying the interaction of components is basic for a railroad project, which is also very important for creating maintenance procedures based on predictions from a model that assumes adequate performance. To determine these interactions, which can have a great number of combinations, the use of a computational model is of vital importance, in this case, the program FERROVIA 1.0 （RAILROAD 1.0） was used. A critical study developed the program FERROVIA 1.0, and its variables were characterized based on values observed in the literature. After initial characterization was carried out, a comparative study was performed on the sensitivity between these variables and the indications of significant behavior for a railway deformed by the known load of a wheel. A statistical program was used to correlate the elements. The intention was to launch the program FERROVIA 1.0 and later use it for 2,187 combinations. The data used in these correlations corresponded to the normal values for the elements used in railroad engineering practice. Our main goal is to understand the behavior of the track vertical deflection according to the variation of the scaling of the various elements of the railway,     

Prevision of Delay in Brazilian Residential Unit Construction Contracts

The aim of this paper is to verify the existence of a clause in contracts of promise of property sale which defines the consequences of delay in the delivery of property, and to discover whether owners demanded any compensation for delays occurred. The number of buildings delivered after the scheduled deadline in two cities between December 2009 and January 2011 was found （n = 542）, and a sample of 82 residential units was taken. In order to obtain the data, a semi-structured questionnaire was given to the homeowners. It was observed that only 35% （n = 29） of the contracts included a penalty clause for delay. However, in 19 of the 29 contracts the clause regarding delay came with other clauses that allowed the company to delay the delivery of the building for up to six months. This clause is considered null in Brazilian legislation. As for compensation, only one （1.82%） owner demanded that the company provide a rental property during the period of delay. It could be concluded that contractors are not observing Brazilian legislation regarding the delay in the delivery of residential units. In addition, conformism is perceived in the attitude of the homeowners.     

Physical model simulation of rock-support interaction for the tunnel in squeezing ground

The existence of squeezing ground conditions can lead to significant challenges in designing an adequate support system for tunnels.Numerous empirical,observational and analytical methods have been suggested over the years to design support systems in squeezing ground conditions,but all of them have some limitations.In this study,a novel experimental setup having physical model for simulating the tunnel boring machine(TBM)excavation and support installation process in squeezing clay-rich rocks is developed.The observations are made to understand better the interaction between the support and the squeezing ground.The physical model included a large true-triaxial cell,a miniature TBM,laboratoryprepared synthetic test specimen with properties similar to natural mudstone,and an instrumented cylindrical aluminum support system.Experiments were conducted at realistic in situ stress levels to study the time-dependent three-dimensional tunnel support convergence.The tunnel was excavated using the miniature TBM in the cubical rock specimen loaded in the true-triaxial cell,after which the support was installed.The confining stress was then increased in stages to values greater than the rock’s unconfined compressive strength.A model for the time-dependent longitudinal displacement profile(LDP)for the supported tunnel was proposed using the tunnel convergence measurements at different times and stress levels.The LDP formulation was then compared with the unsupported model to calculate the squeezing amount carried by the support.The increase in thrust in the support was backcalculated from an analytical solution with the assumption of linear elastic support.Based on the test results and case studies,a recommendation to optimize the support requirement for tunnels in squeezing ground is proposed.     

一个老鼠夹

<正>A rat looked through a crack~1 in the wall and saw the farmer and his wife opening a package.What food might it contain?He was shocked to discover that it was a rat trap.Returning to the farmyard,the rat warned,"There is a rat trap in the house,a rat trap in the house!"一只老鼠透过墙缝看到农夫和他的妻子打开了一个包裹。里面会是什么食物呢?老鼠心     

Redlining in Residential Mortgages in Johannesburg,South Africa

The aim of the research in the paper was to study redlining practice within the greater Johannesburg area. The aim can be summarised by the following objectives： firstly, to investigate the evidence of redlining in the Greater Johannesburg area and to test its existence; secondly, to investigate the reasons why the areas were redlined; thirdly, to understand what the South Africa government and society did to combat the redlining practice. The research methodology was based on a questionnaire and interviews. A pool of respondents from the Greater Johannesburg suburbs that had interest or were affected by the practice of redlining was sought and interviewed. Analysis of the responses was made and conclusions were drawn from the responses. Secondary data was also sought from publications on the redlining practice to support the primary interviews data. From the interview responses and the secondary data, it was established that redlining existed in Greater Johannesburg and that the areas where redlining was practised could be marked on a map.     

Analysis of ground deformation development and settlement prediction by air-boosted vacuum preloading

Vacuum preloading has been widely used to improve soft soils in coastal areas of China.An increasing amount of evidence from field operations has shown that conventional vacuum preloading is prone to clogging in prefabricated vertical drains(PVDs)and demands a large volume of sand fills.In recent years,air-boosted vacuum preloading has been developed to overcome these limitations;however,this method still requires more data to verify its performance.In this study,a field test for air-boosted vacuum preloading was conducted,and a large-strain two-dimensional(2D)finite element(FE)model was developed and validated against the field test data.Then,a series of FE parametric analyses was performed to assess key factors,i.e.the air injection pressure,the injection spacing,and the characteristics of cyclic injection,which affect the performance of the air-boosted vacuum preloading.The results showed that the ground settlement and lateral displacement of the soils increased due to an increase in the injection pressure,a decrease in the injection spacing,or increases in the number and duration of the injection cycles.Based on the parametric analyses,an empirical formula for ground settlement prediction was proposed and compared with a case history reported in the literature,showing good agreement.     

Time-sensitivity mechanism of rock stress memory properties under tensile stress

In deep underground engineering,understanding of time-related stress memory properties is critical to evaluate the in situ stress conditions of a rock mass.In this study,the time-sensitivity mechanism of the rock stress memory properties under tensile stress was investigated.It was found that the material property(Poisson's ratio) and crack angle were the controlling factors of the Kaiser effect(KE) under tensile stress.In particular,the time-sensitivity of the stress memory properties was closely related to the crack growth path.When the failure of the rock specimen was dominated by tensile microcracks and the crack development direction was deflected by up to 30° in the successive loading process,the stress memory capacity was likely to be time-independent for a sandstone specimen.The distribution of the Felicity ratio in a Brazilian test was more discrete than that in a three-point bending test It also showed that the changes in the crack path,rather than the time interval between successive loading cycles,led to inaccuracy of the detected KE.This study provides insights into stress memory-related issues under uniaxial or more complex stress conditions and thus facilitates development of methods for testing in situ mechanical behaviors of rocks with acoustic emission(AE) technology.     

一只海豚的故事

<正>In the tight confines~1 of a cement enclosure~2, a dolphin swam a repeated pattern of circles.It was twilight and she was alone in the tank.在水泥围成的狭小空间里,一只海豚游来游去,一圈一圈地重复着。天黑了,只有它一个人在水箱里。Earlier that day, she had performed her tricks for the people that flocked to see her, and     

Organizational Trouble Shooting through Integration between the Theory of the Restrictions Thinking Process and Lean Tools

The theory of constraints thinking process, created by Israeli physicist Eliyahu M. Goldratt, has emerged as a tool for achieving competitive advantage. Many researches also focused on the application of lean thinking developed by Toyota and proposed by Ohno. This philosophy has been proven to be effective in several production processes. This paper aims to propose a method of problem solving through the integration of theory of constraints thinking process and the principles of lean production. As a tool for problem identification, the method defends the use of current reality tree and, to solve problems, the lean thinking tools, proposed by Picchi. The developed method was implemented in a contractor. The research methodology was research-action. Among the results, there was a realistic diagnosis about the core problems in company. According to this, the core problem of the contractor is “the lack of commitment of manpower” that results in the main problem “the financial loss”. The principle of perfection was verbalized as a proposal to solve the problems and the tools to be implemented for solving problems were “commitment of senior management to employees” and “simplicity in communication”.