Effect of Cross-Linking Waste Protein with Dialdehydes on Its Biodegradation Under Anaerobic Conditions

Most native polymers used in processing and application technologies are admittedly disposable from the environment in a biologic manner, but products possess low mechanical strength. One of the paths to increasing this attribute (if feasible) is their cross-linking, which may, however, affect their readiness to biodegradation. In the presented work this condition was observed on the example of waste protein (Hykol B) cross-linking by means of glutardialdehyde and glyoxal. Degree and course of cross-linking were determined through impedance spectroscopy. The objective of this work also was to obtain data for constructing a sensor capable of following the cross-linking course in real time, for potential industrial application of Hykol in continuous production. Impedance spectroscopy proved to be applicable even to this kind of material marked by considerable water content and exhibiting relatively high electric conductivity; so far it had been used only for materials of low conductivity. An aqueous environment inoculated with digested anaerobic sludge from a municipal wastewater treatment plant was selected for modeling anaerobic conditions. The relation was studied between cross-linking degree given by content of cross-linking agent (determined by impedance spectroscopy) and biodegradation degree under anaerobic conditions. It was confirmed that network density as given by quantity of added agent not only reduced breakdown degree but also slowed the course of the process. This fact is particularly obvious with cross-linking by means of glyoxal; network density is thus dependent on type of employed substance, which affect type and structure of created network. That not merely forms an obstacle during polymer swelling and dissolution but also prevents access of bacteria to source of metabolized organic carbon.     

Physiological responses to atmospheric fluorine pollution in transplants of Pseudoscleropodium purum

Transplants of the moss Pseudoscleropodium purum were placed under shade, and with an auto irrigation system, at five sites in the surroundings of an aluminium smelter to enable study of the possible effects of F on different physiological parameters after exposure periods of 28 and 56 days. Reference thresholds for the content of Chl a+b and for the pigment indexes of Chl a/b and D665/D665a were established with the data corresponding to 22 transplants of each duration of exposure, at seven sites where there was little or no contamination by F. The highest determination coefficients for the levels of F in moss were those obtained for chlorophyll content (Chl a+b) and the D665/D665a pigment index, with the effects being most evident in the transplants exposed to the contamination for 56 days.     

Semi-parametric statistical approaches for space-time process prediction

The problem of estimation and prediction of a spatial-temporal stochastic process, observed at regular times and irregularly in space, is considered. A mixed formulation involving a non- parametric component, accounting for a deterministic trend and the effect of exogenous variables, and a parametric component representing the purely spatio-temporal random variation is proposed. Correspondingly, a two-step procedure, first addressing the estimation of the non- parametric component, and then the estimation of the parametric component is developed from the residual series obtained, with spatial-temporal prediction being performed in terms of suitable spatial interpolation of the temporal variation structure. The proposed model formula-tion, together with the estimation and prediction procedure, are applied using a Gaussian ARMA structure for temporal modelling to space-time forecasting from real data of air pollution concentration levels in the region surrounding a power station in northwest Spain.     

Comparison of Soil Extraction Isotherms of Soil Samples Saturated With Nonpolar Liquids

In multiphase systems capillary pressures play a significant role on fluid movement and retention. The facility to predict the effect of different thermal remediation strategies requires the knowledge of the effect of temperature on capillary pressure-saturation relationships in the soils. The objective of recent study was (a) to develop a technique for routinely measuring the pressure-saturation curves of soil samples saturated with a nonpolar liquid at different regulated temperatures (b) to build a database using the measured pressure-saturation curves and the physical, chemical properties of the model soils (c) to establish the dependence of nonaqueous phase liquid retention on the soil properties and the temperature. The retention curves (extraction isotherms) with nonaqueous phase liquid were determined using a modified pressure plate extractor. The wetting phase was a non-aromatic hydrocarbon distillation product. Pressure plates were designed and constructed in the laboratory of our department. The temperature was held constant at 20, 40 and 60 ^∘C. Statistical analysis was performed involving selected soil parameters and the measured nonaqueous phase liquid retention data. The results show that knowing some easily measurable soil parameters (bulk density, particle size distribution, humus and lime content) we can estimate the nonaqueous phase liquid retention of the soils. The measured “extraction isotherms” provide essential information about the temperature-dependency of pressure-saturation curves.     

Atmospherically deposited major and trace elements in the winter snowpack along a gradient of altitude in the Central Pyrenees: The seasonal record of long-range fluxes over SW Europe

The chemistry of high mountain snowpacks is a result of the long-range atmospheric transport and deposition of elements. Pyrenean snowpacks contain information about the fluxes of elements over SW Europe in winter. Here we analysed Al, Ti, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb in the 2004–05 winter snowpack in the Central Pyrenees, at an altitude range of 1820–3200 m a.s.l. Ni, As, Se and Cd were not detected in most cases. The concentrations of the remaining elements were comparable to those found in other high mountain areas in Europe and North America considered representative of regional background of atmospheric deposition in populated areas. In contrast, our measurements were higher than those of polar areas, which represent the global background. Single measurements of concentrations and snow accumulation were subject to considerable spatial variability, which may be attributable to strong wind drift and other post-depositional processes. The major ions chemistry of the snow indicated three possible origins for the solutes: terrigenous dust, sea salt spray and polluting S and N aerosols. We found no association between Cu, Zn and Pb and any of these possible sources. This observation therefore indicates that these elements were not preferentially bound to any particular kind of aerosol. Snow collected at altitudes of up to 2050 m a.s.l. presented higher concentrations of several elements than snow above this altitude, thereby indicating a local influence. Snow collected above 2300 m a.s.l. was therefore more representative of broad regional inputs. At these higher altitudes, snow was not enriched in Al, Ti, Mn, Fe or As compared with the composition of the upper continental crust and the local lithology, and these elements (except Mn) appeared almost exclusively in the particulate fraction. This observation indicates that Al, Ti, Mn, Fe and As were present mainly as part of dust particles of terrigenous origin. In contrast, Cu, Zn, and Pb presented medium to high enrichment factors and showed a higher proportion of soluble forms, thereby indicating their polluting character.     

The Effect of Protective Gloves on Manual Dexterity in the Cold Environments

This article presents a study on the effect of different protective gloves (which are commercially available and commonly used in the cold) on manual dexterity in cold environments. The experiments compared statistically four different types of gloves and two different types of gloving (outer or double) at +19 °C and -10 °C. Performance was determined both objectively and subjectively using two manual dexterity tasks: bolt-nut and pick-up tasks. The response measured was the time of performing each task. Statistical analysis showed that all independent factors such as glove type, participant, object size, and temperature had significant effects on the hand cooling reaction. A significant difference in the performance between the gloves was found in the bolt-nut task. It was also found that outer-inner combination gloving may be an approach to use for precision tasks.     

Effect of Sweating on Insulation of Footwear

The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19–25% (30–37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.     

Determination of Heat Loss from the Feet and Insulation of the Footwear

This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of thermal foot method, the latter should be preferred for testing.     

A Comparison of Two Methods of Determining Thermal Properties of Footwear

The present European Standard for footwear testing (Standard No. EN 344:1992; European Committee for Standardization [CEN], 1992) classifies footwear thermally by a temperature drop inside the footwear during 30 min at defined conditions. Today, other methods for footwear thermal testing are also available. The aim of this study was to compare EN 344:1992 with a thermal foot method. Six boots were tested according to both methods. Additional tests with modified standard tests were also carried out. The methods ranked the footwear in a similar way. However, the test according to standard EN 344:1992 is a pass-or-fail test, whereas data that is gained from the thermal foot method gives more information and allows further use in research and product development. A change of the present standard method is suggested.