Impact of heat load location and strength on air flow pattern with a passive chilled beam system

A passive chilled beam is a source of natural convection, creating a flow of cold air directly into the occupied zone. Experiments were conducted in a mock-up of an office room to study the air velocities in the occupied spaces. In addition, velocity profiles are registered when underneath heat loads exist and the cool and warm air flows interact. Experimental laboratory study revealed that in the case of the underneath heat gains, even no upward plume was generated and the dummy only acted as a flow obstacle, having a significant effect on the velocity profile. Furthermore, in an actual occupied office environment, the thermal plumes and the supply air diffuser mixed effectively the whole air volume. The maximum air velocity measured was still below 0.25 m/s with the extremely high heat gain of 164 W/m². The results demonstrate that analysis methods were the interaction of convection flow and jet are not taken into account could not accurately describe air movement and draught risk in the occupied room space.     

Students’ Perspectives on the Relevance of Sustainability Literacy in a Postgraduate Built Environment Program

ABSTRACT

Achieving sustainable development in the built environment requires the human resource with the right sustainability knowledge and skills to respond to the challenge facing the construction industry. It is argued that educational institutions have a key role to play in educating future generations with the right sustainability knowledge and skills. This research explores the relevance of sustainability literacy to postgraduate students enrolled in a quantity surveying (QS) course at the London South Bank University. The study adopts a mixed-methods approach that examines students’ perspective on the importance of sustainability literacy and how it has been integrated in the program through interview with 15 students followed by a survey with 98 part-time and full-time students enrolled on the course. The results revealed that students value sustainability knowledge and skills. Most students believe that they need to be sustainability literate to be competitive in the job market. More than half of the students (53%) argued that sustainability literacy was delivered sometimes with a satisfaction rate of 45%, which shows that students are not really happy with how sustainability literacy has been embedded in the course and argues that more needs to be done to fully integrate sustainability literacy in the program.     

Understanding the New Zealand non-domestic building stock

Unlike the residential building stock, most countries have poor information on their non-domestic stock. This necessitates the use of other data sources. In the mid-1980s the (then) New Zealand Department of Valuation digitized its valuation records. This permitted the first analysis of an entire country's non-domestic buildings. A very long-tail probability density function was identified, with the largest 5% of buildings containing more than 40% of the floor space. This knowledge informed the development of research for understanding non-domestic buildings as well as underpinning the 1996 revision of the NZ Building Code Clause H1 Energy Efficiency. More recently an analysis of valuation data has provided the Building Energy End-use Study (BEES) with a national sampling frame to examine energy and water end-uses in non-domestic buildings. The development of processes for collecting and analyzing data is described. Considerable changes in understanding of valuation data have occurred for documenting the non-domestic building stock. New online and geographic information sources can validate and improve building data. The use of such a database supports improved understanding of the changing nature of the building stock and potential intervention points, as well as harnessing regulatory and market forces.     

Overheating and passive habitability: indoor health and heat indices

As extreme heat and weather events are predicted to increase due to global warming, the risk of human heat stress within buildings will increase. To be resilient, buildings will need the capacity to provide habitable indoor conditions without power for limited amounts of time. Additional indoor thermal standards are required for public health to address ‘passive habitability’ during power outages. Current research on building-related heat stress and numerous heat indices is examined in relation to the development of a new heat-safety metric for use in passively conditioned buildings. Most indoor overheating research relies on outdoor temperature data and has no common indoor heat index for evaluating indoor heat stress. A recommendation is made for using the wet-bulb globe temperature (WBGT) and predicted heat strain (PHS) indices for modelling and monitoring of indoor heat stress in healthy adult populations because both indices utilize the primary thermoregulation variables, have associated heat-stress thresholds, and can be assessed or tracked with existing environmental monitoring methods and predictive energy modelling techniques. Further research is recommended on health effects and exposure limits of vulnerable populations, and the variation in thermal factors within buildings and the building stock.     

Effect of diethyl ether blended with neem oil methyl esters in CI engine

Vegetable oils are now considered to be a potential alternative that can be used in place of partial or total substitution of diesel fuels. In this study, we used diethyl ether as an oxygenated additive to investigate the possible use of higher percentages of biodiesel in an unmodified diesel engine. Neem oil was selected for biodiesel production. The tests were performed at a steady-state condition in a single-cylinder constant speed DI diesel engine. The combustion process involved in diesel engine would be improved and the particulate matter would be reduced if these biodiesels are blended. An experimental investigation is carried out to establish the emission characteristics of a direct injection diesel engine using diethyl ether as additive in Neat Neem oil Biodiesel. Emissions of hydro carbon oxides of nitrogen and carbon monoxide significantly reduced by adding diethyl ether into neem oil biodiesel at 10% and 20% on volume basis.     

Noise bias in the refinement of structures derived from single particles

One of the main goals in the determination of three-dimensional macromolecular structures from electron microscope images of individual molecules and complexes (single particles) is a sufficiently high spatial resolution, about 4 A, at which the interpretation with an atomic model becomes possible. To reach high resolution, an iterative refinement procedure using an expectation maximization algorithm is often used that leads to a more accurate alignment of the positional and orientational parameters for each particle. We show here the results of refinement algorithms that use a phase residual, a linear correlation coefficient, or a weighted correlation coefficient to align individual particles. The algorithms were applied to computer-generated data sets that contained projections from model structures, as well as noise. The algorithms show different degrees of over-fitting, especially at high resolution where the signal is weak. We demonstrate that the degree of over-fitting is reduced with a weighting scheme that depends on the signal-to-noise ratio in the data. The weighting also improves the accuracy of resolution measurement by the commonly used Fourier shell correlation. The performance of the refinement algorithms is compared to that using a maximum likelihood approach. The weighted correlation coefficient was implemented in the computer program FREALIGN.     

Concentrations and patterns of organochlorine pesticides and PCBs in Mediterranean monk seals (Monachus monachus) from Western Sahara and Greece

Blubber from Mediterranean monk seals (Monachus monachus) from the Western Sahara coast (Atlantic), sampled during 1996-1999, and from the Greek coast (Mediterranean), sampled during 1995-1999, was analyzed for organochlorine pollutants (OCs). In both populations, no significant difference was found between sexes. In the Atlantic population, mature females presented greater percentages of higher chlorinated PCB (polychlorinated biphenyl) congeners in relation to total PCBs (sum of 25 congeners) than pups, indicating a differential transfer of PCB congeners through lactation. In the Mediterranean, the reduced sample size of adult individuals precluded proper statistical investigation of age-related variation. Significant differences in concentrations and pollutant patterns were found between populations. Thus, Mediterranean individuals presented significantly higher levels of HCB (hexachlorobenzene), tPCB, and DDTs (dichlorodiphenyltrichloroethane) concentrations and DDE/tDDT and tDDT/tPCB ratios than their counterparts from the Atlantic. Moreover, the relative proportion of different congeners in relation to the total PCB load (congener/tPCB) was also different between the two areas. The 100*tDDT/tPCB ratio in Atlantic seals was 38.46, which indicates a predominance of industrial inputs over those associated with agriculture. Conversely, in the Mediterranean seal population, the 100*tDDT/tPCB ratio was 177.1, denoting a proportionally higher contribution of pollutants of agricultural origin.     

Design and performance of pedestrian subway lighting systems

Pedestrian subways can provide for safe and convenient movement of pedestrians across busy roads and similar obstacles. However, fear for personal safety may deter use, particularly at night. Good lighting is an important part of subway design, yet design guides and standards specify only limited criteria for performance, e.g. maintained horizontal illuminance. Various types and arrangements of luminaires are in common use, but as-installed lighting performance is variable. Lighting performance also deteriorates over time, not least due to prevailing environmental conditions. The Hong Kong Government is responsible for over 330 pedestrian subways distributed throughout the territory, making maintenance a significant ongoing commitment. A survey of subway lighting systems has been undertaken to evaluate the performance of the systems against design standards, and to ascertain the opinions of subway users on perceived lighting quality, with a view to identifying the most successful design solutions. Factors affecting the life cycle costs of the most common lighting systems installed in Government maintained subways are also discussed.     

Evaluation of biodegradability of NOM after ozonation

The major purpose of this study was to develop a simple procedure to describe the kinetics of biodegradation of natural organic matter (NOM) in drinking water and to use this procedure to evaluate changes in the concentration of biodegradable organic matter during ozonation and biotreatment. The proposed approach quantitatively describes the formation and removal of rapidly and slowly biodegradable fractions of NOM. This study showed that, depending on source water, ozonation of NOM may result in either minimal formation of biodegradable organic carbon (BDOC), or the formation of predominantly rapidly biodegradable NOM, or in the formation of both rapidly and slowly biodegradable NOM. The kinetic data obtained in this study suggest that while conventional biofiltration processes are capable of removing the rapidly biodegradable fraction, slowly biodegradable organic matter would remain in the filter effluent and may cause bacterial regrowth in the distribution system. An addition of a small amount of easily biodegradable carbon ("stimulated" biodegradation) to ozonated water appears to be effective for the removal of slowly biodegradable organic matter.