Two facets of conscientiousness and the knowledge sharing dilemmas in the workplace: Contrasting moderating functions of supervisor support and coworker support

This study adopts self‐ and other‐centered approaches to explain how the two facets of conscientiousness (i.e., dutifulness and achievement striving) distinctly resolve knowledge sharing dilemmas among employees. It also explores how the critical social surroundings of employees (i.e., supervisor support and coworker support) neutralize or activate the effects of dutifulness and achievement striving on knowledge‐sharing behavior. Our analysis of the data collected from 150 employee–supervisor dyads corroborates that the other‐centered facet of conscientiousness (dutifulness) is positively related to knowledge‐sharing behavior, whereas the self‐centered facet (achievement striving) is negatively related to the same behavior. The analysis also affirms that the positive effect of dutifulness and the negative effect of achievement striving on knowledge sharing are strengthened when supervisor support is low and coworker support is high. This study offers theoretical and practical implications relevant to knowledge management in organizations, distinct roles of facet‐specific personalities toward knowledge sharing, and contrasting personality–situation interactions by situation strength and trait activation in shaping employee behavior.     

Characteristics and potential human health hazards of charged aerosols generated by high-voltage power lines

We investigated the characteristics of charged aerosols produced by high-voltage power lines (HVPLs) to explore the effects on respiratory disease incidence among those who handle HVPLs. Charged aerosol currents and charged aerosol concentrations were measured over 24?h at 12 sites. Aerosol current effective levels were 2.7 times higher compared to exposed and control sites. This pattern of relative enhancement at exposed sites was seen consistently in all measurements and the difference was 1.7 higher at exposed sites. Correlation analysis among all important variables revealed strong positive correlations between currents and concentration, currents and magnetic field, humidity and concentration, and humidity and particles of 10?µm or less (PM₁₀), while negative correlations were observed between charged aerosol concentrations and wind velocity and between wind velocity and humidity. Estimated production of charged aerosols from HVPLs found that people who work with HVPLs are highly likely to be exposed to charged aerosols.     

WATERFALL REAERATION IN THE PASSAIC RIVER1

The effects of waterfall-induced turbulence on the dissolved oxygen concentration of the Passaic River (New Jersey) at two mostly natural waterfalls were observed during a five-month period encompassing high to low temperature and flow. A parameter defined by past investigators as the “deficit ratio” was found to be useful for mathematically describing the results. The Great Falls system showed the deficit ratio to be an inverse function of temperature for all events, with good correlation. A relationship was developed for the Little Falls system under low flow showing the deficit ratio to likewise be an inverse function of temperature and a power function of flow.     

Ozone disintegration of excess biomass and application to nitrogen removal.

A pilot-scale facility integrated with an ozonation unit was built to investigate the feasibility of using ozone-disintegration byproducts of wasted biomass as a carbon source for denitrification. Ozonation of biomass resulted in mass reduction by mineralization as well as by ozone-disintegrated biosolids recycling. Approximately 50% of wasted solids were recovered as available organic matter (ozonolysate), which included nonsettleable microparticles and soluble fractions. Microparticles were observed in abundance at relatively low levels of ozone doses, while soluble fractions became dominant at higher levels of ozone doses in ozone-disintegrated organics. Batch denitrification experiments showed that the ozonolysate could be used as a carbon source with a maximum denitrification rate of 3.66 mg nitrogen (N)/g volatile suspended solids (VSS) x h. Ozonolysate was also proven to enhance total nitrogen removal efficiency in the pilot-scale treatment facility. An optimal chemical oxygen demand (COD)-to-nitrogen ratio for complete denitrification was estimated as 5.13 g COD/g N. The nitrogen-removal performance of the modified intermittently decanted extended aeration process dependent on an external carbon supply could be described as a function of solids retention time.     

The combination of zinc compounds and acidic pH limits aerobic growth of a Salmonella typhimurium poultry marker strain in rich and minimal media

The objective of the present study was to examine the combined effects of zinc compounds with different acidic pH levels on the aerobic growth of a S. typhimurium poultry isolate in either rich or minimal media. When overall main effects of pH levels of medium or concentrations of Zn compounds were compared, growth rates of the S. typhimurium poultry isolate were significantly (p < 0.05) decreased by stepwise increase of pH levels of medium (pH 4, 5, 6, and 7) or concentrations (0.67, 3.35, and 6.03%) of Zn compounds (Zn acetate and Zn sulfate). In general growth rates of S. typhimurium poultry isolate appeared to be more reduced by Zn acetate than by Zn sulfate and more reduced in minimal media compared to rich media.     

Waste green sands as reactive media for the removal of zinc from water

Waste green sands are industrial byproducts of the gray iron foundry industry. These green sands are composed of fine silica sand, clay binder, organic carbon, and residual iron particles. Because of their potential sorptive and reactive properties, tests were performed to determine the feasibility of using green sands as a low cost reactive medium in permeable reactive barriers (PRBs). Serial batch kinetic tests and conventional batch sorption tests were conducted to determine the removal characteristics for zinc in aqueous solutions. Removal characteristics for zinc in the presence of green sands are comparable to those of Peerless iron, a common reactive medium used in PRBs. High removal capacities for zinc of green sands are attributed to clay, organic carbon, and residual iron particles, which are known sorptive media for heavy metals. Furthermore, high pH values in the presence of clay and residual iron particles enhanced sorption and precipitation of zinc.     

Effect of gas velocity and influent concentration on biofiltration of gasoline off-gas from soil vapor extraction

This study was conducted to evaluate the effects of gas inlet concentration and velocity on the biofiltration of gasoline vapor. Gasoline vapor was treated using a compost biofilter operated in an upflow mode for about 3 months. The inlet concentration of gasoline total petroleum hydrocarbon (TPH) ranged from about 300 to 7000 mgm(-3) and gas was injected at velocities of 6 and 15 mh(-1) (empty bed residence time (EBRT)=10 and 4 min, respectively). The maximum elimination capacities of TPH at 6 and 15 mh(-1) found in this research were over 24 and 19 gm(-3) of filling material h(-1), respectively. TPH removal data was fit using a first-order kinetic relationship. In the low concentration range of 300-3000 mg m(-3), the first-order kinetic constants varied between about 0.10 and 0.29 min(-1) regardless of gas velocities. At TPH concentrations greater than 3000 mgm(-3), the first-order kinetic constants were about 0.09 and 0.07 min(-1) at gas velocities of 6 mh(-1) and 15 mh(-1), respectively. To evaluate microbial dynamics, dehydrogenase activity, CO2 generation and microbial species diversity were analyzed. Dehydrogenase activity could be used as an indicator of microbial activity. TPH removal corresponded well with CO2 evolution. The average CO2 recovery efficiency for the entire biofilter ranged between 60% and 70%. When the gas velocity was 6 mh(-1), most of the microbial activity and TPH removal occurred in the first quarter of the biofilter. However, when the gas velocity was 15 mh(-1), the entire column contributed to removal. Spatial and temporal variations in the biofilter microbial population were also observed. Nearly 60% of the colonies isolated from the compost media prior to biofiltration were Bacillus. After 90 days of biofiltration, the predominant species in the lower portion (0-50 cm) of the filter were Rhodococcus, while Pseudomonas and Acinetobacter dominated the upper portion (75-100 cm).     

Regional measurements of PCDD/PCDF concentrations in Korean atmosphere and comparison with gas-particle partitioning models

The current investigation was aimed at determining the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) in the Korean atmosphere along with their estimation using gas-particle partitioning. Samples collected from six cites showed that large cities were polluted with a concentration of 0.593 pg TEQ/m3. Samples were also collected from residential (nine sites), commercial (five sites), and industrial (seven sites) districts in each city. Higher levels of PCDDs/PCDFs were observed in industrial area than other areas, since it includes many sources. Higher chlorinated 2,3,7,8-substituted congeners were predominantly found in the particulate phase. HpCDD/Fs and OCDD/Fs shared 97-99% of the particulate phase, whereas TCDD/Fs, which dominated the gaseous phase, shared 34.8% and 42.8% in 2,3,7,8-substituted congeners. The regression dataset was transformed due to the relationship between log K(P) and log P(L)o. A wide variation was observed in the slopes for the residential areas when compared with the slopes for the commercial and industrial areas. The Junge-Pankow model and K(oa) adsorption model were both found to be helpful in describing the gas-particle partitioning in the current study.     

Use of waste iron metal for removal of Cr(VI) from water

Cr(VI) removal from water was evaluated using waste iron particles in batch experimental mode. The reaction rates were inversely proportional to the initial Cr(VI) concentrations, and the reaction rates of Cr(VI) removal with the waste iron metal were faster than those with Peerless iron, a commercial zero-valent iron. The loss in iron reactivity due to the oxidation, from Fe(0) to Fe(II), ultimately to Fe(III), could be recovered by adding iron-reducing consortium (IRC) to the oxidized iron. Bacterial reduction of Cr(VI) also helped to decrease the aqueous concentration of Cr(VI), but the reduction of oxidized iron by IRC and the consequent reduction of Cr(VI) to Cr(III) by the reduced iron was more significant. Thus, reusing waste iron metal for Cr(VI) removal can reduce the cost of reactive media. Furthermore, the addition of IRC to the waste iron metal can accelerate the removal rate of Cr(VI), and can recover the reactivity of irons which were oxidized by Cr(VI).     

Taking advantage of aerated-anoxic operation in a full-scale University of Cape Town process.

To evaluate the potential benefits or limitations of aeratedanoxic operation in high-rate biological nutrient removal processes, we conducted a full-scale experiment in a University of Cape Town (UCT)-type wastewater treatment plant by reducing oxygen supply and increasing flowrates within one treatment train so that aerated-anoxic conditions (i.e., zones that receive oxygen but maintain dissolved oxygen concentrations below 0.5 mg/L) could be implemented in a section of the aerated zone. With this retrofitted configuration, total nitrogen removal increased from 54 to 65%, but was limited by the organic carbon available for denitrification. Furthermore, the significant reduction in dissolved oxygen concentrations in the aerated zone did not negatively affect enhanced biological phosphorus removal, demonstrating that the implementation of an aerated-anoxic zone within a UCT-type reactor can contribute to a reduction in operational costs and a slight improvement in total nitrogen removal, without compromising the extent of phosphorus removal.