An approach for determining the extent of contribution of construction project features to accident causation

In the pursuit of Health and Safety (H&S) improvement within the UK construction industry, several studies have been conducted to identify accident causal factors to enable the development of accident prevention measures. Adding to such studies, a critique of H&S literature demonstrates that construction project features (CPFs) such as the nature of project, method of construction, site restriction, project duration, procurement system, design complexity, level of construction, and subcontracting contribute to accident causation and that their contribution is through the introduction of proximal accident causal factors into the construction process. However, the extent of this contribution by these CPFs remains sparingly known and requires further investigation. The study provides this insight by indicating that the extent to which CPFs contribute to accident causation is influenced by two factors; the extent to which the proximal factors contribute to accident causation; and the extent to which the proximal factors are prevalent within the CPFs. In line with this fresh insight, an approach for determining the extent to which CPFs contribute to accident causation is put forth. The approach proposes to use a qualitative–quantitative rating scale to determine the two determinant factors and then combine them using a mathematical formula to obtain the extent to which CPFs contribute to accident causation. By this approach the grey areas in literature concerning the extent to which CPFs contribute to accident causation will be illuminated and by that contribute to improvement in construction accident prevention.     

Microplankton dynamics of a coastal lagoon,Chilika: interactive effect of environmental parameters on microplankton groups

Microplankton population of Asia’s largest coastal lagoon Chilika was studied for five major groups, bacillariophyceae, cyanophyceae, chlorophyceae, dinophyceae, rotifera, and tintinninae. The study reported presence of 233 species of microplankton whose average annual abundance was 1631 cells/l. The physicochemical parameters contributing to the spatio-temporal fluctuations in microplankton diversity, abundance, and community structure were identified as salinity, pH, DO, nitrate, and silicate. Salinity, transparency, depth, and silicate most explained the abundance of bacillariophyceae; nitrate, pH, and DO influenced cyanophyceae; salinity, transparency, and chlorophyll concentration influenced chlorophyceae; salinity, depth, and water temperature influenced dinophyceae; salinity, free CO2, and nitrate-influenced rotifers, whereas salinity, pH, DO, and depth influenced tintinnids. Biotic-abiotic relationships revealed particular preference of environmental conditions at species level in groups like bacillariophyceae, cyanophyceae, and dinophyceae. Although the lagoon is shallow, bacillariophyceae-environment interaction showed depth can be a critical factor for species like Aulocoseira sp., Amphipleura sp., and Rhophalodia sp. Species of dinoflagellates like Dinophysis caudata, Noctiluca scintillans, and Protoperidinium proliferated in lower level of silicate. Unlike other cyanophyceae species Streptococcus sp., Chroococcus sp., Diplococcus sp., Aphanocapsa sp., and Gloeocapsa sp. were negatively influenced by nitrate concentration. The study provides better scope for ecological management of the lagoon with respect to conserving biodiversity and hydrological quality of the ecosystem.     

UVΑ pre-irradiation to P25 titanium dioxide nanoparticles enhanced its toxicity towards freshwater algae Scenedesmus obliquus

Environmental Science and Pollution Research - There has recently been an increase in the usage of TiO2 nanoparticles (NPs). P25 TiO2 NPs, a mixture of anatase and rutile phase in 3:1 ratio, are...     

Facile and Sensitive Spectrophotometric Determination of Synthetic Pyrithroids in Their Formulations, Water and Grain Samples

A novel reagent was introduced for the facile and sensitive spectrophotometric determination of syntheitic pyrethroids in their formulations (fenvalerate, cypermethrin and decamethrin), water and grain samples. These methods were based on the hydrolysis of synthetic pyrethroids under the alkaline conditions to form respective aldehyde groups. These groups were condensation with 3-methyl-2-benzothiazolinone hydrochloride (MBTH) to yield color derivatives having λ_max at 520 nm for fenvalerate, 516 nm for cypermethrin and 512 nm for decamethrin. The proposed method could be successfully applied for the determination of synthetic pyrethroids in their formulations, water and grain samples.     

Temporal trend studies on polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in ringed seals from east Greenland

The concentrations of polybrominated diphenyl ethers (PBDEs) 17, 28, 47, 49, 66, 85, 99, 100, 153, 154, and 183 were determined in ringed seal blubber from central East Greenland collected in 1986, 1994, 1999 and during the period 2001 to 2004. The trend of PBDEs was compared with the trends of polychlorinated biphenyls (PCBs) 28, 31, 52, 101, 105, 118, 138, 153, 156, and 180 during the same period. The levels of sigmaPBDE in East Greenland ringed seals ranged from 21.8 ng g(-1) lipid weight (1w) in 1986 to 39.3 ng g(-1) lw in 2001 and are among the highest observed in ringed seal from the Arctic. The dominating congeners were BDE-47 (75.4%) and BDE-99 (9.7%). The concentrations of PBDEs and PCBs increased with the age of the seals, and therefore only young seals < or =4 years old) were included in the temporal trend analyses. No significant trend (p > 0.14) was observed in sigmaPBDE or the congeners BDE 28, 47 and, 99 during the period while sigmaPCB decreased significantly (p = 0.004) over the period from 1986 to 2004 with an estimated annual rate of 4.3%.     

Numerical Modeling on the Effect of Dissolved Oxygen on Nitrogen Transformation and Transport in Unsaturated Porous System

Nitrogen pollution in groundwater resulting from wastewater application to land is a common problem, and it causes a major threat to groundwater-based drinking water supplies. In this study, a numerical model is developed to study the nitrogen species transport and transformation in unsaturated porous media. Further, a new mass transfer module for dissolved oxygen (DO) is incorporated in the one-dimensional numerical model for nitrogen species transport to describe the fate and transport of nitrogen species, dissolved oxygen, dissolved organic carbon (DOC), and biomass. The spatial and temporal variation of dissolved oxygen is incorporated in the model through the mass transfer from gaseous phase to water phase in an unsaturated porous system. The numerical results of the water flow model and single species and multispecies transport model in an unsaturated zone developed for this purpose have been validated with the available analytical/numerical solution. The developed model is applied in clay loam, silt, and sand soils to analyze the transport behavior of nitrogen species under unsaturated condition. The numerical results suggest that the high rate of oxygen mass transfer from the air phase to the water phase positively increases the dissolved oxygen in the applied wastewater and enhances the nitrification process. Because of this high oxygen mass transfer, the nitrate nitrogen concentration significantly increases in the unsaturated zone and the same is transported to a larger depth at higher simulation period. On the other hand, the low rate of oxygen mass transfer implicitly enhances the denitrification process and finally reduces the nitrate nitrogen concentration in the unsaturated zone. The numerical results also show that the nitrate nitrogen transport is rapid in sandy soil when compared with clay loam and silty soils under high oxygen mass transfer rate. In essence, the high oxygen mass transfer rate significantly increases the nitrate nitrogen in the unsaturated zone, especially at a greater depth at larger time levels and eventually affects the groundwater quality.     

Development of controlled release formulations of carbofuran and imidacloprid and their bioefficacy evaluation against aphid, Aphis gossypii and leafhopper, Amrasca biguttula biguttula Ishida on potato crop

Controlled release (CR) formulations of carbofuran and imidacloprid were prepared employing polyvinyl chloride and carboxymethyl cellulose (CMC) and their bioefficacy was evaluated against the aphid, Aphis gossypii and leafhopper, Amrasca biguttula biguttula Ishida on potato crop. The CR formulations of carbofuran and imidacloprid provided better or equal control of the pests than commercial formulations. CMC-based formulation provided a superior control of both the pests. The Imida-CMC, which showed the lowest population of leaf hopper (10.50 leafhopper/100 cl), provided significantly superior control among all treatments after 35 days after germination (DAG). The residue of carbofuran and imidacloprid in potato tuber and soils were not detectable at the time of harvesting in any one of the formulations.     

Spatial distribution of aerosol black carbon over India during pre-monsoon season

Aerosol black carbon (BC) mass concentrations ([BC]), measured continuously during a mutli-platform field experiment, Integrated Campaign for Aerosols gases and Radiation Budget (ICARB, March–May 2006), from a network of eight observatories spread over geographically distinct environments of India, (which included five mainland stations, one highland station, and two island stations (one each in Arabian Sea and Bay of Bengal)) are examined for their spatio-temporal characteristics. During the period of study, [BC] showed large variations across the country, with values ranging from 27 μg m^?3 over industrial/urban locations to as low as 0.065 μg m^?3 over the Arabian Sea. For all mainland stations, [BC] remained high compared to highland as well as island stations. Among the island stations, Port Blair (PBR) had higher concentration of BC, compared to Minicoy (MCY), implying more absorbing nature of Bay of Bengal aerosols than Arabian Sea. The highland station Nainital (NTL), in the central Himalayas, showed low values of [BC], comparable or even lower than that of the island station PBR, indicating the prevalence of cleaner environment over there. An examination of the changes in the mean temporal features, as the season advances from winter (December–February) to pre-monsoon (March–May), revealed that: (a) Diurnal variations were pronounced over all the mainland stations, with an afternoon low and a nighttime high; (b) At the islands, the diurnal variations, though resembled those over the mainlands, were less pronounced; and (c) In contrast to this, highland station showed an opposite pattern with an afternoon high and a late night or early morning low. The diurnal variations at all stations are mainly caused by the dynamics of local Atmospheric Boundary Layer (ABL). At the entire mainland as well as island stations (except HYD and DEL), [BC] showed a decreasing trend from January to May. This is attributed to the increased convective mixing and to the resulting enhanced vertical dispersal of species in the ABL. In addition, large short-period modulations were observed at DEL and HYD, which appeared to be episodic. An examination of this in the light of the MODIS-derived fire count data over India along with the back-trajectory analysis revealed that advection of BC from extensive forest fires and biomass-burning regions upwind were largely responsible for this episodic enhancement in BC at HYD and DEL.     

Studies on the use of low-volatile non-edible oils in a thermal barrier-coated diesel engine

Owing to the ever-increasing vehicle population, the consumption of diesel fuel in the transportation, agricultural and industrial sectors has increased at an alarming rate. This has led to rapid fossil fuel depletion, ozone depletion and environmental degradation, which have become a serious concern. Search for alternative renewable and clean energy fuel sources to mitigate the emissions of greenhouse gases is continuing, and attempts to find different techniques for efficient utilization of these fuels are also undertaken. Biodiesel being an oxygenated fuel obtained from vegetable oils has received greater attention over the years as a promising alternative to diesel fuel. However, vegetable oils exhibit high viscosity, poor volatility and poor cold-flow characteristics. These characteristics can cause the following problems in the engine when run for a longer duration: injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication. These problems can be eliminated or minimized by adopting suitable fuel processing techniques to obtain biodiesels from vegetable oils. The fuel processing techniques vary widely, which include transesterification, supercritical methanolysis, ultrasonic and continuous microwave-assisted transesterification methods. In the present study, the transesterification method is effectively used to obtain biodiesels from non-edible oils of honne and cotton seed. The biodiesels obtained from these oils were used in the unmodified diesel engine to check their feasibility as diesel engine alternatives. Different thermal barrier coatings (TBCs) were applied on the piston, cylinder head, and inlet and exhaust valve surfaces of the diesel engine in order to make it a fully adiabatic engine. The engine with such TBCs is called a low heat rejection engine. For the present study, the TBC of partially stabilized zirconia (PSZ) and aluminium oxide (Al₂O₃) were selected. Finally, the performance of the diesel engine fuelled with different biodiesels in both conventional and thermal barrier-coated modes was compared. The thermal barrier-coated engine with the PSZ version showed better performance with increased nitric oxide emissions when compared with the Al₂O₃ coating.     

Effects of injection timing,injector opening pressure and nozzle geometry on the performance of cottonseed oil methyl ester-fuelled diesel engine

Increasing petroleum prices, increasing threat to the environment from exhaust emissions and global warming have generated intense international interest in developing renewable and alternative non-petroleum fuels for engines. Evolving technology and a recurring energy crisis necessitates a continuous investigation into the search for sustainable and clean-burning renewable fuels. In this paper, cottonseed oil methyl ester (COME) was used in a four-stroke, single-cylinder variable compression ratio diesel engine. Tests were carried out to study the effects of fuel injection timing, fuel injector opening pressure (IOP) and injector nozzle geometry on the performance and combustion of COME biodiesel fuel used in a compression ignition engine with a single fuel mode. Fuel injection timing varied from 19° to 27° before top dead centre (bTDC) in incremental steps of 4° bTDC; fuel IOP varied from 210 to 240 bar in incremental steps of 10 bar. Fuel nozzle injectors with three, four and five holes, each of 0.3 mm size, were selected for the study. The results suggested that with retarded injection timing of 19° bTDC, increased IOP of 230 bar and a four-hole nozzle injector of 0.3 mm size resulted in overall better engine performance with an increased brake thermal efficiency and reduced HC, CO and smoke emission levels.