Uncertainty of measurement or of mean value for the reliable classification of contaminated land

Classification of contaminated land is important for risk assessment and so it is vital to understand and quantify all of the uncertainties that are involved in the assessment of contaminated land. This paper uses a case study to compare two methods for assessing the uncertainty in site investigations (uncertainty of individual measurements, including that from sampling, and uncertainty of the mean value of all measurements within an area) and how the different methods affect the decisions made about a site. Using the ‘uncertainty of the mean value’ there is shown to be no significant possibility of ‘significant harm’ under UK guidance at one particular test site, but if you consider the ‘uncertainty of the measurements’ a significant proportion (50%) of the site is shown to be possibly contaminated. This raises doubts as to whether the current method using ‘uncertainty of the mean’ is sufficiently robust, and suggests that ‘uncertainty of measurement’ information may be preferable, or at least beneficial when used in conjunction.     

分光光度法测定水中氨氮的不确定度评定

目的对分光光度法测定水中氨氮含量的不确定度的来源及其对测量不确定度的影响进行分析。方法利用相对标准不确定度进行测量不确定度的评定。过程采用直观的因果图,建立有效的数学模型,利用相对标准不确定度分量进行测量不确定度评定,并在氨氮测定含量为5．5μg／mL的水样中获得其相对合成标准不确定度为4．77％。结论水样中氨氮含量测定的测量不确定度影响因素中,校准曲线斜率引起的不确定度最大,占3．69％,其次是测定时吸光度值和体积引起的不确定度,占3．03％。     

Evaluating schedule delay causes for private participating public construction works under the Build-Operate-Transfer model

Project delivery method of Build-Operate-Transfer (BOT) increases the commencement probability of public construction works through private investments. Public construction works worldwide that adopt the BOT model as their project delivery method are increasing gradually. Although many BOT projects have been implemented at various stages, some projects encounter major obstacles for advancement. This study attempts to identify the delay causes in various stages of BOT projects. Opinions of BOT participants’ replies are solicited using two questionnaire surveys. Those outcomes are analyzed using by traditional statistical methods and structural equation modeling method. Study results reveal that the stage of ‘negotiation and signing of concession agreement’ is the most essential stage, in which ‘improper contract planning,’ ‘debt problem’ and ‘uncertainty on political issues and government-finished items’ are the most significant delay causes. Identified causes of delay can be used to prevent the postponement of future BOT projects.     

On-line parameter estimation and optimal control strategy of a double-skin system

To reduce the potential problems of window systems such as undesired heat gain (loss), glare, and thermal discomfort due to asymmetric radiation, double-skin systems have been introduced. The current problem with double-skin systems is that their operation requires an adequate simulation model to realize optimal control of the system. The estimation of the parameters in the lumped model developed in a previous study [1] was based on ‘laborious’ off-line calibration procedure. This effort has to be repeated for every different size, different type, or differently oriented façade system. Different façade components are characterized by different thermal and optical properties of glazing and blind slats, system configurations [height, width, depth], other simulation variables, etc. For each type the parameter set in the lumped model has to be established through a calibration procedure. In view of micro climate variations even same type systems within one façade but on different heights may have to be calibrated separately. In order to avoid the laborious off-line calibration of every single façade component, an on-line self-calibrating procedure is developed in this paper. The true advantage of the technique is that every component can be pre-wired and ready to be hooked to the calibration set-up when it is brought to the site. The paper will explain the simulation model, selection of calibration parameters, and the process of on-line self-calibration, model validation and application of optimal control. It is shown that the on-line self-calibrating simulation model far outperforms the off-line calibrated model. Consequently, the plug and play self-calibration technique will render the current in-situ ‘laborious’ off-line calibration process obsolete.     

Transition regions: Regional-national eco-innovation systems and strategies

The key phenomenon around which the paper is constructed, given its core interest in the transition from a fossil fuels energy regime to a zero emissions and/or renewable energy regime (sometimes also ‘post-hydrocarbons’ regime; Smith, 2008), is the notion and explanation of ‘transition regions’. These are sub-national territories, usually with some degree of devolved governance in the fields of innovation, economic development and energy that, for reasons to be demonstrated, act as regional ‘lighthouses’ for eco-innovation both to other regions and countries. These are the places that are subject to ‘learning visits’ by global policy-makers and other interested parties eager to learn how success was achieved. Because regions differ within state-systems, the case material is presented according to three kinds of political model. These are, first, the liberal market model, notably north America and the UK; second is the co-ordinated market model such as Germany and some Nordic countries; and third hybrids which have a reasonably entrepreneurial economic climate typical of the ‘liberal market’ model but strong welfare states, more typical of the ‘co-ordinated market’ model such as Denmark, a small state, and China, a large one. Finally, each of six cases will be presented in the sequence of the ‘system’ and regional governance of ‘transition regions’ first, with the nature and role of the national eco-innovation regime summarised afterwards where top-down governmental influence is clearly visible, even weakly. Also eco-innovations that are broadly in the same field, such as renewable energy production, or electric vehicle consumption are studied, giving maximum comparative value from their emergence in different countries and regions.     

A study on subjective preference to daylit residential indoor environment using conjoint analysis

This paper reports a study of the subjective preference to daylit indoor environment of a residential room using conjoint analysis, which is a highly reputable method used to analyze the mutual relationships among different attributes. Seven influential attributes were selected in the view of daylight performance assessment. They include ‘general brightness’, ‘desktop brightness’, ‘perceived glare’, ‘sunlight penetration’, ‘quality of view’, ‘user friendliness of shading control’ and ‘impact on energy’. Each of them has two levels. A total of eight combinations (profiles) of attributes with various levels were established by adopting fractional factorial design. Subjects were asked to rank-order the eight profiles according to their preference in terms of daylit environment of a residential room. The study aims at finding out the relative impact of the seven selected attributes to the overall daylight performance and seeking an organized assessment method for a residential daylit environment. Conjoint analysis found that the seven attributes have importance level in the order of ‘quality of view’, ‘general brightness’, ‘impact on energy’, ‘user friendliness of shading control’, ‘perceived glare’, ‘desktop brightness’ and ‘sunlight penetration’.     

Deliberate ignorance in project risk management

The management of project risk is considered a key discipline by most organisations involved in projects. Best practice project risk management processes are claimed to be self-evidently correct. However, project risk management involves a choice between which information is utilized and which is deemed to be irrelevant and hence excluded. Little research has been carried out to ascertain the manifestation of barriers to optimal project risk management such as ‘irrelevance’; the deliberate inattention of risk actors to risk. This paper presents the results of a qualitative study of IT project managers, investigating their reasons for deeming certain known risks to be irrelevant. The results both confirm and expand on Smithson’s [Smithson, M., 1989. Ignorance and Uncertainty. Springer-Verlag, New York] taxonomy of ignorance and uncertainty and in particular offer further context related insights into the phenomenon of ‘irrelevance’ in project risk management. We suggest that coping with ‘irrelevance’ requires defence mechanisms, the effective management of relevance as well as the setting of, and sticking to priorities.     

Source apportionment of heavy metals and ionic contaminants in rainwater tanks in a subtropical urban area in Australia

Due to prolonged droughts in recent years, the use of rainwater tanks in urban areas has increased in Australia. In order to apportion sources of contribution to heavy metal and ionic contaminants in rainwater tanks in Brisbane, a subtropical urban area in Australia, monthly tank water samples (24 sites, 31 tanks) and concurrent bulk deposition samples (18 sites) were collected during mainly April 2007-March 2008. The samples were analysed for acid-soluble metals, soluble anions, total inorganic carbon and total organic carbon, and characteristics such as total solid and pH. The Positive Matrix Factorisation model, EPA PMF 3.0, was used to apportion sources of contribution to the contaminants. Four source factors were identified for the bulk deposition samples, including ‘crustal matter/sea salt’, ‘car exhausts/road side dust’, ‘industrial dust’ and ‘aged sea salt/secondary aerosols’. For the tank water samples, apart from these atmospheric deposition related factors which contributed in total to 65% of the total contaminant concentration on average, another six rainwater collection system related factors were identified, including ‘plumbing’, ‘building material’, ‘galvanizing’, ‘roofing’, ‘steel’ and ‘lead flashing/paint’ (contributing in total to 35% of the total concentration on average). The Australian Drinking Water Guideline for lead was exceeded in 15% of the tank water samples. The collection system related factors, in particular the ‘lead flashing/paint’ factor, contributed to 79% of the lead in the tank water samples on average. The concentration of lead in tank water was found to vary with various environmental and collection system factors, in particular the presence of lead flashing on the roof. The results also indicated the important role of sludge dynamics inside the tank on the quality of tank water.     

An emission-weighted proximity model for air pollution exposure assessment

Background

Among the most common spatial models for estimating personal exposure are Traditional Proximity Models (TPMs). Though TPMs are straightforward to configure and interpret, they are prone to extensive errors in exposure estimates and do not provide prospective estimates.

Method

To resolve these inherent problems with TPMs, we introduce here a novel Emission Weighted Proximity Model (EWPM) to improve the TPM, which takes into consideration the emissions from all sources potentially influencing the receptors. EWPM performance was evaluated by comparing the normalized exposure risk values of sulfur dioxide (SO₂) calculated by EWPM with those calculated by TPM and monitored observations over a one-year period in two large Texas counties. In order to investigate whether the limitations of TPM in potential exposure risk prediction without recorded incidence can be overcome, we also introduce a hybrid framework, a ‘Geo-statistical EWPM’. Geo-statistical EWPM is a synthesis of Ordinary Kriging Geo-statistical interpolation and EWPM. The prediction results are presented as two potential exposure risk prediction maps. The performance of these two exposure maps in predicting individual SO₂ exposure risk was validated with 10 virtual cases in prospective exposure scenarios.

Results

Risk values for EWPM were clearly more agreeable with the observed concentrations than those from TPM. Over the entire study area, the mean SO₂ exposure risk from EWPM was higher relative to TPM (1.00 vs. 0.91). The mean bias of the exposure risk values of 10 virtual cases between EWPM and ‘Geo-statistical EWPM’ are much smaller than those between TPM and ‘Geo-statistical TPM’ (5.12 vs. 24.63).

Conclusion

EWPM appears to more accurately portray individual exposure relative to TPM. The ‘Geo-statistical EWPM’ effectively augments the role of the standard proximity model and makes it possible to predict individual risk in future exposure scenarios resulting in adverse health effects from environmental pollution.     

City edges in Germany: Quality growth and urban design

Forty years of explosive growth have dissolved the hard edge of old walled cities throughout Germany. Undefined suburban mess has consumed vast areas of land and degraded picturesque German landscapes. The new interest in strengthening local identities coincides with national priorities to enhance the cultural and natural heritage. Policies for quality growth at the city's edge evolve through a series of steps, including the community's vision statements, comprehensive master planning, environmental prioritization of potential development sites, and land banking for mitigation of future impacts. The merits of high density urban form with strategically placed ‘hard’ and ‘soft’ edges include preservation of landscape with special environmental and scenic value; proximity of residential and recreational areas; convenient and car-free transit; and openness contrasts with urban density.     

Fatigue behaviour of a PET-Geogrid under cyclic loading

The lines of ‘damage-begin’ and ‘specimen-break’ for dynamic loading of a geogrid were determined in a series of laboratory testing. The cyclic load ratio was set to R = 0.5, loading frequency f = 10 Hz and f = 3 Hz. The test results show clearly that the chosen procedure for the determination and analysis of the beginning of damage and break is reproducible and allow for safe extrapolation for lower load levels. Furthermore the method chosen enables explicit decrease of the required testing time. The assumption of linear damage accumulation was examined in two-step-trials. The number of load cycles to ‘break’ evaluated in ‘one-step-tests’ compared with those of ‘two-step-loading’ are practically the same. The existence of ‘damage-lines’ for the examined geogrid under a dynamic pulsating load of 10 Hz and 3 Hz and a R-value of 0.5 could be verified. Damage of the specimens occurs only for load-cycles lying between the ‘damage-line’ and the ‘stress-cycle-diagram’ (‘Woehler-curve’). When it comes to dimensioning against ‘damage-beginning’ or ‘break’, higher loading frequencies present the critical case.     

Estimating municipal solid waste generation by different activities and various resident groups: a case study of Beijing

Reliable and accurate determinations of the quantities and composition of wastes is required for the planning of municipal solid waste (MSW) management systems. A model, based on the interrelationships of expenditure on consumer goods, time distribution, daily activities, residents groups, and waste generation, was developed and employed to estimate MSW generation by different activities and resident groups in Beijing. The principle is that MSW is produced by consumption of consumer goods by residents in their daily activities: ‘Maintenance’ (meeting the basic needs of food, housing and personal care), ‘Subsistence’ (providing the financial requirements) and ‘Leisure’ (social and recreational pursuits) activities. Three series of important parameters - waste generation per unit of consumer expenditure, consumer expenditure distribution to activities in unit time, and time assignment to activities by different resident groups - were determined using a statistical analysis, a sampling survey and the Analytic Hierarchy Process, respectively. Data for analysis were obtained from the Beijing Statistical Yearbook (2004-2008) and questionnaire survey. The results reveal that ‘Maintenance’ activity produced the most MSW, distantly followed by ‘Leisure’ and ‘Subsistence’ activities. In 2008, in descending order of MSW generation the different resident groups were floating population, non-civil servants, retired people, civil servants, college students (including both undergraduates and graduates), primary and secondary students, and preschoolers. The new estimation model, which was successful in fitting waste generation by different activities and resident groups over the investigated years, was amenable to MSW prediction.     

Succeeding programmes,failed projects: A lexicographical analysis of a disputed semantic terrain

This paper proposes that projects and programmes can be empirically distinguished by the way in which they are associated with expectations and evaluations of success and failure. Support for the proposition is grounded in analysis of over sixteen hundred examples of occurrences of the terms ‘project’ and ‘programme’ with ‘success’ and ‘failure’ derived from the Oxford English Corpus (OEC). The OEC is a structured and coded database of over two billion words of naturally occurring English collected from the World Wide Web. The analysis highlights that project and programme are each modified by the terms ‘success’ and ‘failure’ in significantly different ways, indicating that they are conceptually distinct phenomena. These findings imply that academics must be cautious in their use of language in investigations of project and programme evaluations, and that practitioners should consider the implications of considering programmes as ‘scaled‐up’ projects, given their propensity to different evaluation outcomes.     

A computational investigation of particle distribution and deposition in a 90° bend incorporating a particle–wall model

This paper investigates the particle flow movement and deposition in a 90° bend after a straight duct, utilizing the Lagrangian particle-tracking model incorporated with a particle–wall collision model. Particle turbulent dispersion is introduced by employing the ‘eddy lifetime’ model, and particle deposition velocity in the bend is proposed by counting the number of deposited trajectories in a time period. The developed models are validated for both airflow and particle flow by previous experimental data. Particle distribution and deposition behavior at five size groups (1, 3, 5, 9, and 16 μm) are investigated. The simulation results show that, compared with traditional ‘Trap’ model, the particle–wall collision model postpones the emergence and slows the increase of the ‘particle free zone’ as the particle diameter increases. Particle deposition velocity in the duct bend is also generally predicted by the proposed estimation equation under the simulated conditions. This reveals that adopting the particle–wall collision model obtains a reasonable prediction of particle distribution and deposition in the duct bend. This work will benefit the understanding and application of microparticle flow in curved duct systems.     

Towards an organizational culture framework in construction

Organizational culture gives identity to an organization. Notwithstanding the individuality of the staff members, their actions are collectively bound by the organizational culture. A review of the literature in this topic reveals that despite a number of organizational culture models have been developed, these are mainly for generic business settings and there has yet one developed for construction contracting organizations. This paper reports a study for this purpose conducted in Hong Kong. Firstly, artifacts of organizational culture were long-listed through a literature review. Construction professionals working for developers, consultant offices and contractors assessed the appropriateness of using these artifacts to identify organizational culture in construction. Through a principal component factor analysis, these artifacts are arranged into a seven-factor organizational culture framework. The seven factors are ‘Goal settings and accomplishment’, ‘Team orientation’, ‘Coordination and integration’, ‘Performance emphasis’, ‘Innovation orientation’, ‘Members’ participation’ and ‘Reward orientation’. The ANOVA result suggests no significant difference in the rankings across respondents working for developers, consultants and contractors. The relative importance rankings among these factors were also assessed according to their significance scores. The findings of the study suggest that the construction contracting organizations in Hong Kong favor culture of clear goals with stability. They are less externally focused with a relatively lower emphasis on innovation. These findings suggest construction maintains a local industry mentality.     

Relationships between air-tightness and its influencing factors of post-2006 new-build dwellings in the UK

Addressing air leakage of dwellings is important to improving energy efficiency and thermal comfort. This paper reports on the air permeability test results of 287 post-2006 new-build dwellings in the UK. The paper explores the relationships between air-tightness and its influencing factors including build method, dwelling type, management context, design target, season, number of significant penetrations, and envelope and floor area. One-way ANOVA analysis was utilised to compare means of air permeability in relation to the individual factors, and two- and three-way ANOVA analyses were applied for examining the interactions between them. The air-tightness of the dwellings averaged 5.97 m³/(h m²) at 50 Pa, which has improved from UK historic data. Dwellings built using precast concrete panels were significantly air-tighter than those built using timber frame, whilst those masonry and reinforced concrete frame dwellings were most leaky. Greater extent of innovative practice and ‘self-build’ procurement led to achieving superior air-tightness. Interaction was observed between ‘build method’ and ‘dwelling type’ and between ‘dwelling type’ and ‘management context’. A modest positive correlation was noticed between air permeability and design target, which became weak in relation to the number of significant penetrations and envelope area. Applying the linear regression technique a predictive model is developed for estimating air permeability of dwellings. This model integrates the influencing factors and their significant interactions. The findings should contribute to future research in predicting impacts of controlling the influencing factors on achieving air-tightness of dwellings more consistently.     

Contradictions in California’s orientalist landscape: Architecture, history and Spanish-Colonial Revival

Although Spanish-Colonial Revival architecture and place-names dominates Southern California’s landscape, one also finds examples of simulated Middle Eastern bazaars, references to Ancient Egypt, and the use of iconography from non-European Old World. While the region’s landscape is arguably a product of bricolage and postmodern sensibilities, this article looks at the history of ‘Orientalism’ in Southern California’s built environment. In particular, I am looking at the precedents for this seemingly contradictory use of the ‘Oriental’ in the region. The ‘Oriental’ as a sinfully seductive means of creating spectacle in the built environment is both glorified and demonized in popular discourse. For example, the ‘Oriental’ is celebrated in shopping malls, but demonized culturally and politically. However, it is in this contradiction that we can see how history and ideology has shaped the vernacular landscape. As such, this article will look at early twentieth century examples of the ‘Oriental’ in Spanish-Colonial Revival as a foundation to understand contradictions in the built environment, culture, and racial hierarchies.     

Analysis of architects' demotivating factors in design firms

The overall aim of this study is to identify factors that influence architects' demotivation in design firms. After a review of extant literatures in design management, project management, and organisational behaviour, a list of 43 demotivating criteria was produced and used in a questionnaire survey. Analyses included reliability analysis, Mann–Whitney U and Kruskal–Wallis tests, demotivation severity index (DSI) computation and exploratory factor analysis. Results show an underlying factor structure of seven demotivating factors that include ‘organisational injustice’, ‘project induced stress’, ‘dysfunctional design team’, ‘poor interpersonal relationships’, ‘perceived career decline’, ‘negative leadership behaviours’ and ‘poor organisational culture’. Comparing these demotivational factors with motivational factors identified from previous related research, this study confirms that demotivation and motivation are on the same pole. In addition, what causes motivation or demotivation is a function of individual frame of reference. This implies that the presence or absence of a factor might cause motivation or demotivation depending on an individual frame of reference. Positive attention to the identified factors in relation to individual personality differences therefore helps to remove impediments that could affect employees' well-being such as being downcast, dispirited, depressed and despondent. The study would help directors and managers of design firms to develop a healthy workforce through recognition and eradication of the identified demotivating factors using some of the suggested solutions.     

An experimental study on the appraisal of the visual environment at offices in relation to colour temperature and illuminance

Colour temperature and illumination level have affected the subjective impressions at an office setting. 2000 lx was preferred to 500 lx for impressions of comfort, spaciousness, brightness and saturation evaluation. A 4000 K colour temperature was preferred to 2700 K for impressions of ‘comfort and spaciousness’, while 2700 K was suggested for ‘relaxation’ and ‘saturation evaluation’. Test results indicate that, task–background contrast is more important and shall be studied for ‘perceived brightness’ evaluation. Participants liked the ‘mixed colour temperature mood’, the remote control and the flexibility in the lighting system and the majority offered to use it at offices.     

Virtual in-situ calibration method in building systems

Sensors play an important role in guiding building systems to achieve desired operation and efficiency. However, sensors are subject to continuous degradation and failures over time. Although a periodical calibration is needed, it is exceptionally difficult and/or impractical to many sensors with a conventional manual approach. Uncalibrated problematic sensors could significantly compromise the systems' performance and lead to unintended loss of energy efficiency in buildings. We propose a methodology, termed virtual in-situ calibration, to solve this critical issue. It is developed by mathematically extracting the characteristics of essential aspects involved in a calibration, including the environment assessment, benchmark establishment, and uncertainty quantification. A case study of a supply air temperature sensor in rooftop units illustrates the implementation process; the erratic uncertainty is reduced from ± 19.2 °C to ± 0.7 °C after the virtual in-situ calibration. The calibration method can be implemented online to significantly improve the reliability of sensor networks in buildings.