Decision‐making in a model‐based design process

Decisions early in the design process have a big impact on the life cycle performance of a building. The outcome of a construction project can be improved if different design options can rapidly be analysed to assist the client and design team in making informed decisions in the design process. A model‐based design approach can facilitate the decision‐making process if the design alternatives' performances can be evaluated and compared. A decision‐making framework using a performance‐based design process in the early design phase is proposed. It is developed to support decision‐makers to take informed decisions regarding the life cycle performance of a building. A scenario is developed in order to demonstrate the proposed framework of evaluating the different design alternatives' energy performance. The framework is applicable to decision‐making in a structured design process, where design alternatives consisting of both objective and subjective evaluation criteria can be evaluated.     

Role of microorganisms in water purification of compounds of iron and manganese in a dense layer of sorbent–catalyst

The article contains assessment and contains experimental substantiation of the involvement of iron- and manganese-oxidizing microorganisms in the removal of manganese compounds from model solutions. Defined and identified are cultures of such microorganisms. The article has shown the efficiency of removing manganese compounds by the layer of a sorbent–catalyst under conditions of changing the temperature conditions for a long time.     

Determination of polycyclic aromatic hydrocarbons in sea water using solid‐phase microextraction

Solid‐phase microextraction (SPME) technique with poly(dimethylsiloxane)‐coated fiber has been employed for the rapid determination of sixteen polycyclic aromatic hydrocarbons (PAHs) present in natural water. The method is solvent‐less with the analytes being adsorbed and then desorbed thermally at the injector port of a gas chromato‐graph (GC) prior to mass spectrometric (MS) analysis in selective ion monitoring (SIM) mode. The influences of the injector port temperature, desorption time and initial oven temperature on the thermal desorption of PAHs from the fiber were investigated. Then the optimum SPME conditions were applied for the qualitative and quantitative determination of PAHs in environmental samples. The recoveries of the 16 PAHs being spiked into sea water at 50 ng/mL level were 75.3%. The levels of PAHs in the Singapore coastal sea water are between 0.02–8.50 ng/mL using SPME(PDMS).     

The work‐life experiences of office and site‐based employees in the Australian construction industry

A survey was conducted among employees of a large Australian construction firm. Comparisons were made between employees who differed by gender and work location. Male employees in site‐based roles reported significantly higher levels of work to family conflict and emotional exhaustion than male employees who worked in the regional or head office. Site‐based male employees were also less satisfied with their pay than male respondents who worked in the regional of head office. Few significant differences were found between women who worked in different locations. Neither were significant differences between men and women who worked in the same location reported. The results are explained in terms of women's tendency to work in administrative, secretarial or support services roles, which typically demand fewer hours. The paper concludes that the experiences of site‐based construction employees, particularly men, warrant further attention to explore the sources of work‐life imbalance and burnout.     

Catenary variation of vegetation in a swamp forest in South‐Western Nigeria

The study examines catenary differentiation of swamp forest vegetation in an area characterised by low gentle relief. There are no marked variations in vegetation structure along the catena, except near the river bank where trees are shorter, and tree density lower. Tree species are also fewer near the river bank. Because the ground water table is quite close to the surface, swamp‐loving species, especially Lophira alata Oxystigma mannii and Symphonia globulifera occur in the upper, middle and lower slope units of the catena. Raphia spp. are, however, restricted to the middle and lower slopes, being the most characteristic and abundant species of the lower slope where flooding is more pronounced. Ground slope and ground elevation are the most significant factors influencing variation in tree height and number of trees species along the catena, soil textural composition and nutrient status being relatively unimportant.     

Degradation of 14c‐maneb in sediment from a Nicaraguan estuary

Sediment samples were collected at 5 sites in the Nicaraguan estuary “El Naranjo” in July 94 and September 94. The samples were incubated with ¹⁴C‐maneb (0.08 μg.g^‐1 dw sediment), and evolved ¹⁴CO₂ and residual ¹⁴C‐ETU in soil were measured. Mineralization kinetics of ^I4C‐maneb was best described with kinetic models which include growth of microorganisms. The amounts of ¹⁴C‐maneb mineralized were highest at the sites closest to the mouth of the river. No significant differences in degradation between July and September were seen. After 67 days between 9.73 and 16.18% of added ¹⁴C had evolved as ¹⁴CO₂ in the July samples and after 150 days between 11.18 and 27.37% of added ¹⁴C had evolved as ¹⁴CO₂ from the September samples. When 4.61–8.20% of added ^I4C was found in the soil extract, 0.00–2.72% was ¹⁴C‐ETU.     

Development of De-NOx selective catalytic reduction catalyst using V2O5 –TiO2 supported on a ceramic filter candle

This study reports the development of a V₂O₅-TiO₂-based selective catalytic reduction (SCR) catalyst supported on alumina-silicate water filter candles for NO_x abatement. The synthesised catalysts have been characterised by thermogravimetry/differential scanning calorimetry, X-ray diffraction, scanning electron microscope and measurement of NO_x removal performance. The catalyst synthesised under optimal conditions shows NO_x reduction efficiency of >97%. SCR performance has been augmented using O₂ as a carrier gas. This simple, reproducible procedure can have wide applications in NOx abatement.     

Performance evaluation of a pure oxygen‐based activated sludge system treating a combined paint industry wastewater and domestic sewage

Activated sludge system based on pure oxygen has been developed to increase the biodegradation of wastewater. This system was used for the treatment of combined wastewater from the paint industry effluent and sewage. The results of continuous test showed that it is possible to achieve 87.8–93.6% COD, and 97.7–99.2% of BOD removal resulting in an effluent quality of 55–90mg/L of COD and less than 10.0mg/L of BOD. Dissolved oxygen content through out the tank showed a concentration, ranging between 3.26 and 3.9mg/L, indicating good oxygenation in the system. Excess sludge generated in the ASP was found to be 3.0kg/d and it has a good manurial value with NPK of 112, 68 and 32mg/L, respectively. Moreover the sludge showed very good settling character with a capillary suction time of 8.0 seconds.     

Influence of physico‐chemical factors on the coliform bacteria in a closed‐lake water system

This investigation is concerned with an examination of the coliform group of micro‐organisms responsible for causing pollution in drinking waters. Bacterial counts (MPN) were correlated with certain physical and chemical factors, viz. electrical conductivity, pH, temperature, Ca‐Mg hardness, inorganic nitrogen substances, inorganic sulphate and phosphate contents of the water. The coliform counts (MPN) varied with seasonal variations and changes in the properties of the water bodies. An inverse correlation of bacterial counts was noted with the dissolved inorganic nitrogenous compounds like ammonia, nitrite and nitrate. Similar observations were made when compared with dissolved salts of phosphate and sulphate.     

Three‐dimensional analytical model of atmospheric dispersion of pollutant in a stable boundary layer

A three‐dimensional atmospheric dispersion model of a heavy admixture emitted from an elevated continuous point source is presented. Appropriate boundary conditions have been employed to model the effects of various removal mechanisms like deposition, settling and leakage of pollutants. This model takes care of variation of mixing layer height with heat flux, geostrophic drag by terrain and several meteorological parameters. A realistic form of variable eddy diffusivity is used in this model for a stable atmospheric condition. It has been found that the effect of settling of large particles is to reduce pollutant concentration always far away (horizontally as well as vertically) from the source. Whereas, in the lower part of the boundary layer near the source its effect is to increase concentration for small values of settling velocity and to decrease for larger values. The present model, being three dimensional in nature, is more suitable to assess the impact of point source emission.     

A case‐based reasoning approach to application of value engineering methodology in the construction industry

A key point in value engineering (VE) methodology is to acquire and apply knowledge of the assorted fields. An appropriate definition of VE expert knowledge flow could, therefore, yield more productive VE workshops. A conceptual expert case‐based reasoning (CBR) framework is introduced in this paper to form a coherent basis for the provision of practically suitable VE expert models. The proposed framework outlines knowledge entities and their relations in the VE workshop. The model benefits from a fuzzy approach to handle uncertainties in the evaluation phase of the methodology. In addition, a computer program is devised, based on the proposed framework, using Borland Delphi 7.0. It comprises an interface representing several phases of the VE job plan. The model is employed in a tunnelling project to demonstrate feasibility of the model in a practical workshop. Owing to its expert nature, the developed model contributes to efficiency of the methodology through providing VE teams with canalized expert knowledge of diverse domains. The propounded model may avail researchers in promoting expert models for pre‐construction and specifically VE studies in major construction projects.     

Safety climate in conditions of construction subcontracting: a multi‐level analysis

A multi‐level safety climate model was tested in the Australian construction industry. Subcontracted workers’ perceptions of the organizational safety response (OSR) and supervisor safety response (SSR) in their own organization and that of the principal contractor were measured using a safety climate survey administered at a large hospital construction project in Melbourne. One hundred and fourteen construction workers completed the survey, representing nine subcontractors engaged at the project. Two requisite conditions for the existence of group‐level safety climates, i.e. (1) within‐group homogeneity; and (2) between‐group variation were satisfied for perceptions of subcontractors’ OSR and SSR. This supports the contention that subcontractors working in a single construction project exhibit a unique group‐level safety climate. Subcontracted workers also discriminated between group‐level safety climates (i.e. the SSR) in their own and in the principal contractor’s organizations. The results suggest some cross‐level influence. Perceptions of the SSR were positively predicted by perceptions of the OSR in both the principal and subcontractor organizations. Perceptions of the OSR of the principal contractor were also a significant predictor of the perceived OSR and SSR in the subcontractor organizations. Perceptions of the subcontractors’ SSR were a significant predictor of the rate of lost‐time and medical treatment incidents reported by the subcontractor. Although perceptions of the principal contractor’s SSR were not directly related to subcontractors’ injury rates, they were a significant predictor of subcontractors’ SSR, revealing an indirect link. The results suggest that supervisory personnel (e.g. foremen and leading hands) play an important role in shaping safety performance in subcontracted workgroups.     

Stakeholder impact analysis of infrastructure project management in developing countries: a study of perception of project managers in state‐owned engineering firms in Vietnam

Construction projects can involve a diverse range of stakeholders and the success of the project depends very much on fulfilling their needs and expectations. It is important, therefore, to identify and recognize project stakeholders and develop a rigorous stakeholder management process. However, limited research has investigated the impact of stakeholders on construction projects in developing countries. A stakeholder impact analysis (SIA), based on an approach developed by Olander (2007), was adopted to investigate the stakeholders’ impact on state‐owned civil engineering projects in Vietnam. This involved the analysis of a questionnaire survey of 57 project managers to determine the relative importance of different stakeholders. The results show the client to have the highest level of impact on the projects, followed by project managers and the senior management of state‐owned engineering firms. The SIA also provides suggestions to project managers in developing and evaluating the stakeholder management process.     

An analysis of sustainable development and environmental protection in postcommunist countries: the case of croatia‐a view point

The paper analyses the origins, the definitions, and the implementation of sustainable development in the post‐communist countries of Central and Eastern Europe, using Croatia as an example. The overview of events in environmental concern world‐wide, in the last 25 years, shows that there is evidence of fast changes which have left the former communist countries behind. The major concern of the paper is the lack of an agreed upon definition and criteria on what sustainable development actually represents, and why it is still an odd subject in the Central and Eastern European region. Five recognition criteria described in the open literature are compared with the situation in the region. Using the examples of implementation of new UN Conventions, accepted at the UNCED Conference in Rio de Janeiro in 1992, the paper discusses the shortcomings and obstacles to current policies of sustainability.     

Impact of physico‐chemical parameters on the microbial population and its nature in a major retting zone of Kerala

As part of an environmental abatement programme, through the application of bioremediation in the retting zones of Kerala, a microbiological survey was conducted during March 1999 in the Kadinamkulam kayal, a major retting zone in Kerala. Some selected physico‐chemical parameters were also analysed to assess the water quality in the context of retting activity. Comparatively low dissolved oxygen content coupled with high hydrogen sulphide observed at Stations 1 and 2 can be attributed to retting. Salinity distribution is of the mixohaline nature. Pseudomonas sp., E. coli and other coliform groups were found to be present in the area. Of these the most dominant was Pseudomonas sp. and hence its nature and plasmid profile were also studied. The study indicates an environmental degradation in the area, and the possibility of hotspots of pollution in the backwater biotopes in the State.     

Lead and cadmium in teeth,bone and kidneys of rats with a standard Pb‐Cd supply

Male Wistar rats received a combination of 25 ppm PbCl₂ and 5 ppm CdCl₂ in drinking water at different developmental stages. Pb and Cd levels of incisors, molars, epiphyses, diaphyses and kidney cortex were recorded by atomic absorption spectrophotometry. The results confirmed that Pb has an affinity for hard tissue and especially to teeth, but it also accumulated in soft tissues under the above conditions. In addition, the results indicated none or only a moderate placental or mammary barrier for Pb, and suggested a high absorption of lead from the intestine of sucklings. The results also confirmed that kidney cortex is a primary target for Cd, and indicated that Cd has crossed the placental and mammary barriers to some degree. The positive significant correlation between Cd levels in molars and kidney cortex suggested that rodent molars indicate a degree of Cd absorption, whereas incisors do not. It is supposed that rodent molars are comparable to human deciduous teeth. It is thus confirmed that human deciduous teeth indicate previous lead exposure. It is further inferred that they also can be used as indicators of previous Cd‐exposures.     

Innovation in small construction knowledge‐intensive professional service firms: a case study of an architectural practice

Small construction knowledge‐intensive professional service firms (SCKIPSFs) are becoming increasingly important agents of innovation within the construction industry. The nature and process of innovation in SCKIPSFs, however, is generally considered through the constraining prism of research results generated from significantly different contexts, such as from manufacturing sectors or non‐project based firms. A theory of innovation for SCKIPSFs is developed from a longitudinal 22‐month case study of a small architectural practice. Two forms of knowledge‐based innovation were discerned from the empirical work: exploitative innovation and explorative innovation. ‘Explorative innovation’ was found to be located in immediate ‘new’ project domains, and entailed search, variation, experimentation, activity to solve project‐specific problems; while ‘exploitative innovation’ concentrated on developing generic organisational infrastructure to ‘refine’ and ‘improve the efficiency’ of the firm operations to nurture capability for future activity. The key challenge for SCKIPSFs is to develop and manage an appropriate balance between explorative and exploitative innovation over time in order to generate sustainable competitive advantage.     

Toward a sustainable land management of vernacular landscape in the highlands of south‐western Saudi Arabia: indigenous and statutory experiences

The vernacular landscape of the highlands of south‐western Saudi Arabia comprises three distinct elements: natural, agricultural and built. The highlands are currently facing land use planning problems which result in deforestation, despite significant attempts at afforestation by several governmental agencies (especially the Ministry of Agriculture and Water) and by municipal governments in the area. Intentions towards more sustainable forms of land management now characterize official documents. With regard to landscape issues, this is marked by a discourse of sustainable land management and the sponsorship of initiatives addressing the relationship between land management and the environment. This paper demonstrates that the approach to sustainable land management is technical, rational and scientific. A more balanced approach would combine scientific knowledge and practice with traditional expertise.