Deformation due to Mechanical and Thermal Sources in a Thermoelastic Body with Voids under Axi-symmetric Distributions

The Laplace and Hankel transforms have been employed to find the general solution of a homogeneous, isotropic, thermoelastic half-space with voids for a plane axi-symmetric problem. The application of a thermoelastic half-space with voids subjected to a normal force and a thermal source acting at the origin has been considered to show the utility of the solution obtained. To obtain the solution in a physical form, a numerical inversion technique has been applied. The results in the form of displacements, stresses, temperature distribution, and change in volume fraction field are computed numerically and illustrated graphically for a magnesium crystal-like material to depict the effects of voids in the theory of coupled thermoelasticity (CT) and uncoupled thermoelasticity (UCT) for an insulated boundary and a temperature gradient boundary.     

Characterization of diesel particles: effects of fuel reformulation, exhaust aftertreatment, and engine operation on particle carbon composition and volatility

Diesel exhaust particles are the major constituent of urban carbonaceous aerosol being linked to a large range of adverse environmental and health effects. In this work, the effects of fuel reformulation, oxidation catalyst, engine type, and engine operation parameters on diesel particle emission characteristics were investigated. Particle emissions from an indirect injection (IDI) and a direct injection (DI) engine car operating under steady-state conditions with a reformulated low-sulfur, low-aromatic fuel and a standard-grade fuel were analyzed. Organic (OC) and elemental (EC) carbon fractions of the particles were quantified by a thermal-optical transmission analysis method and particle size distributions measured with a scanning mobility particle sizer (SMPS). The particle volatility characteristics were studied with a configuration that consisted of a thermal desorption unit and an SMPS. In addition, the volatility of size-selected particles was determined with a tandem differential mobility analyzer technique. The reformulated fuel was found to produce 10-40% less particulate carbon mass compared to the standard fuel. On the basis of the carbon analysis, the organic carbon contributed 27-61% to the carbon mass of the IDI engine particle emissions, depending on the fuel and engine operation parameters. The fuel reformulation reduced the particulate organic carbon emissions by 10-55%. In the particles of the DI engine, the organic carbon contributed 14-26% to the total carbon emissions, the advanced engine technology, and the oxidation catalyst, thus reducing the OC/EC ratio of particles considerably. A relatively good consistency between the particulate organic fraction quantified with the thermal optical method and the volatile fraction measured with the thermal desorption unit and SMPS was found.     

In vitro blood and fibroblast responses to BisGMA–TEGDMA/bioactive glass composite implants

This in vitro study was designed to evaluate both blood and human gingival fibroblast responses to bisphenol A–glycidyl methacrylate–triethyleneglycol dimethacrylate (BisGMA–TEGDMA)/bioactive glass (BAG) composite, aimed to be used as composite implant abutment surface modifier. Three different types of substrates were investigated: (a) plain polymer (BisGMA 50 wt%–TEGDMA 50 wt%), (b) BAG–composite (50 wt% polymer + 50 wt% fraction of BAG–particles, <50 μm), and (c) plain BAG plates (100 wt% BAG). The blood response, including the blood–clotting ability and platelet adhesion morphology were evaluated. Human gingival fibroblasts were plated and cultured on the experimental substrates for up to 10 days, then the cell proliferation rate was assessed using AlamarBlue assay?. The BAG–composite and plain BAG substrates had a shorter clotting time than plain polymer substrates. Platelet activation and aggregation were most extensive, qualitatively, on BAG–composite. Analysis of the normalized cell proliferation rate on the different surfaces showed some variations throughout the experiment, however, by day 10 the BAG–composite substrate showed the highest (P < 0.001) cell proliferation rate. In conclusion, the presence of exposed BAG–particles enhances fibroblast and blood responses on composite surfaces in vitro.     

Nitrate, nitrite, and N-nitroso compounds in Finnish foods and the estimation of the dietary intakes

Summary An estimate of the dietary intakes of nitrite, nitrate andN-nitroso compounds is presented, based on the analytical data supplied by the Finnish Food Quality Control. Figures on the food consumption of the Finnish population, taken from a national dietary survey, and food consumption of 1768 children and adolescents over a 48-h recall period were used. The mean daily dietary nitrate intakes were estimated to be about 55 mg for the total population and for children and adolescents. The mean nitrite intakes were 1.88 mg for the total population and 1.07 mg for children and adolescents. The intake ofN-nitroso compounds (NDMA) was estimated to be 0.08 g for the total population and 0.02 g for children. Nitrates were found to originate mainly from vegetables (80%), nitrites from meat products (97%) and nitrosamines mostly from fish products and beer. A comparison of the estimate of dietary intake of nitrite with ADI values indicated that the nitrite intake of the total population was 23% and by children 39% of ADI. The average weight was approximately 60 kg for adults and 20 kg for children. When measured average weight (39 kg) was used, and the nitrite intake was found to be 28% of ADI. Nitrate intakes from food additives were 2.5% and 1.4% of the ADI value, respectively. When the total nitrate intake from various food sources was compared with the ADI (which is given only for food additives), the estimated nitrate intake of the total population was 25% and that of children 28% of the ADI value.

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Nitrat, Nitrit und N-nitroso-Verbindungen in der finnischen Nahrung

Zusammenfassung Die Einnahme von Nitrat, Nitrit undN-Nitroso-Verbindungen stützt sich auf die analytischen Werte der finnischen Lebensmittelkontrolle. Für die Schätzung der Nahrungsaufnahme der finnischen Bevölkerung benutzte man Resultate einer nationalen Nahrungsforschung und eines 48-Stunden-Befundes für 1768 Kinder und Jugendliche. Die durchschnittliche tägliche Einnahme von Nitrat schätzte man auf ungefähr 55 mg für die ganze Bevölkerung. Die durchschnittliche Einnahme von Nitrit betrug 1,88 mg für die ganze Bevölkerung und 1,07 mg für Kinder und Jugendliche. Die Einnahme vonN-Nitroso-Verbindungen (NDMA) schätzte man auf 0,08 g für die ganze Bevölkerung und 0,02 g für Kinder. Die hauptsächliche Nahrungsquelle der Nitrate war Gemüse (80%) und bei den Nitriten die Fleischwaren (97%). Nitrosamine stammten hauptsächlich aus Fischwaren und aus Bier. Als man die geschätzte Einnahme von Nitrit mit den ADI-Werten verglich, ergab sich, daß die Einnahme von Nitrit 23% (ganze Bevölkerung) und 39% (Kinder) des ADI-Wertes war. Als durchschnittliches Körpergewicht nahm man 60 kg für Erwachsene und 20 kg für Kinder an. Wenn man den Wert des gemessenen durchschnittlichen Körpergewichts (39 kg) für Kinder benutzte, war die Einnahme von Nitrit 28% des ADI-Wertes. Die Einnahme von Nitrat in Zusatzstoffen war 2,5% und entsprechend 1,4% des ADI-Wertes. Die Einnahme von Nitrat in der Nahrung schätzte man auf 25% (ganze Bevölkerung) und auf 28% (Kinder) des ADI-Wertes (gegeben nur für Nitrat als Zusatzstoffe).

     

Effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in Lake Hiidenvesi (southern Finland)

The effects of submerged macrophytes on sediment resuspension and internal phosphorus loading in the shallow Kirkkoj?rvi basin of Lake Hiidenvesi were studied by sedimentation traps and sediment and water samples. During the 83 d study period, 793 g DW m(-2) of sediment was resuspended within the stand formed by Ranunculus circinatus, Ceratophyllum demersum and Potamogeton obtusifolius. Outside the stand, 1701g DW m(-2) sediment resuspension was measured during the same period. Water turbidity and concentration of suspended solids (SS) were significantly lower within the plant bed compared with the surrounding water area. Despite the higher concentration of inorganic suspendoids, the concentration of chlorophyll a was higher in the open water than within the submerged plant bed, owing to the enhanced nutrient recycling rate in the absence of submerged plants. With the resuspended sediment, 11.8 mg Pm(-2)d(-1) was brought into the water column within the stand and 24.5 mg Pm(-2)d(-1) outside the stand. Within the macrophyte stand, resuspended particles absorbed phosphorus from the water (indicated by the inverse relationship between SS and soluble reactive phosphorus), which was probably connected to the lowered phosphorus concentration of surface sediment due to uptake by macrophytes.     

Development of an urban health and wellbeing index for work precincts: A comparative study in Sydney,Australia

Work precincts are recognized for their significant role as generators of employment and associated commerce within urban areas. This study describes a method for analyzing the physical characteristics of urban work precincts in promoting the health and wellbeing of their occupants. The following physical parameters are analyzed: public transport accessibility, green and blue spaces, food environments, fitness facilities, supermarkets, and grocery stores. The parameters are assessed using quantitative spatial analysis based on street network data, as well as point of interest data acquired from OpenStreetMap (OSM). The streets and their intersections are stored in the OSM database as links and nodes, respectively. The evaluation of the performance metrics involves measuring the street network distance from each node to the closest node of interest for each parameter. The metrics are then combined, forming an urban health and wellbeing index (UHWI), which can be used to compare the performance of different precincts. The method was tested by investigating four work precincts in Sydney, Australia, all hosting a large office building belonging to the same business institution. Our results identified two of the four precincts with a high UHWI and resulted in the identification of one underperforming precinct.