Correlation between Pitch Impregnation Pressure and Pore Sizes of Graphite Block

This study aimed to investigate the effect of impregnation pressure on the decrease in porosity of impregnated bulk graphite. The correlation between pitch impregnation behavior and the pore sizes of the bulk graphite block was studied to determine the optimal impregnation pressure. The densities and porosities of the bulk graphite before and after pitch impregnation under various pressures between 10 and 50 bar were evaluated based on the Archimedes method and a mercury porosimeter. The density increased rates increased by 1.93–2.44%, whereas the impregnation rate calculated from the rate of open porosity decreased by 15.15–24.48%. The density increase rate and impregnation rate were significantly high when the impregnation pressures were 40 and 50 bar. Compared with impregnation pressures of 10, 20, and 30 bar, the minimum impregnatable pore sizes with impregnation pressures of 40 and 50 bar were 30–39 and 24–31 nm, respectively. The mercury intrusion porosimeter analysis results demonstrated that the pressure-sensitive pore sizes of the graphite blocks were in the range of 100–4500 nm. Furthermore, the ink-bottle-type pores in this range contributed predominantly to the effect of impregnation under pressure, given that the pitch-impregnated-into-ink-bottle-type pores were difficult to elute during carbonization.

Interaction of plasma with beryllium

In this work shows some results of studying the microstructure of HP-56 beryllium after plasma irradiation. The experiments revealed a change in the microstructure of beryllium after irradiation with hydrogen, deuterium and helium atoms. The pore diameter and their bulk density increase depending on the plasma parameters.

Observations of linear aggregation behavior in rotifers (Brachionus calyciflorus)

Linear aggregation is present in some animals, such as the coordinated movement of ants and the migration of caterpillars and spinylobsters, but none has been reported on rotifers. The rotifers were collected and clone cultured in the laboratory at 25 ± 1°C, under natural light (light intensity ~130 lx, L:D = 14:10). The culture medium(pH = 7.3) was formulated as described by Suga et al., and rotifers were fed on the micro algae Scenedesmus obliquus grown in HB-4 medium to the exponential growth stage. When density was high (150 individuals ml-1), the behavior of rotifers was observed using a stereo microscope (Motic ES-18TZLED). In this paper, linear aggregation in Brachionus calyciflorus was found for the first time, and experiments were carried out to verify the correlation between linear aggregation and culture density of B. calyciflorus. With the increase of density, the number of aggregations increase, the number of individuals in the aggregation increased, and the maintenance time of the aggregation was also increased. Therefore, we speculate that the formation of aggregates is related to density and may be a behavioral signal of density increase, which may transmit information between density increase and formation of dormant eggs.

Population, Education and Income Inequality

In non-democracies, a large population size and density lead to more redistributive policies and lower income inequality. This is the result of the interconnection of two intermediate hypotheses. First, in non-democracies a larger population size and density increase the chance of a revolution attempt to overthrow the governing elites. Second, this revolution threat prompts the elites to better re-distribute the country’s income in an attempt to fend off this threat. This paper suggests and empirically tests that wider spread primary and, to a lesser extent, secondary education is one of the channels through which the elites achieve this better distribution.

The retail food environment and its association with body mass index in Mexico

Background/Objective Mexico has one of the highest rates of obesity and overweight worldwide, affecting 75% of the population. The country has experienced a dietary and food retail transition involving increased availability of high-calorie-dense foods and beverages. This study aimed to assess the relationship between the retail food environment and body mass index (BMI) in Mexico. Subjects/Methods Geographical and food outlet data were obtained from official statistics; anthropometric measurements and socioeconomic characteristics of adult participants (N = 22,219) came from the nationally representative 2012 National Health and Nutrition Survey (ENSANUT). Densities (store count/census tract area (CTA)) of convenience stores, restaurants, fast-food restaurants, supermarkets and fruit and vegetable stores were calculated. The association of retail food environment variables, sociodemographic data and BMI was tested using multilevel linear regression models. Results Convenience store density was high (mean (SD) = 50.0 (36.9)/CTA) compared with other food outlets in Mexico. A unit increase in density of convenience stores was associated with a 0.003 kg/m2 (95% CI: 0.0006, 0.005, p = 0.011) increase in BMI, equivalent to 0.34 kg extra weight for an adult 1.60 m tall for every additional 10% store density increase (number of convenience stores per CTA (km2)). Metropolitan areas showed the highest density of food outlet concentration and the highest associations with BMI (β = 0.01, 95% CI: 0.004–0.01, p < 0.001). A 10% store density increase in these areas would represent a 1 kg increase in weight for an adult 1.60 m tall. Conclusions Convenience store density was associated with higher mean BMI in Mexican adults. An excessive convenience store availability, that offers unhealthy food options, coupled with low access to healthy food resources or stores retailing healthy food, including fruits and vegetables, may increase the risk of higher BMI. This is the first study to assess the association of the retail food environment and BMI at a national level in Mexico.

10 MA cm−2 current density in nanoscale conductive bridge threshold switching selector via densely localized cation sources

Super-ionic cation layer was introduced into the CBTS selector to realize ten-fold current density increase.

Determination of the limits of the density of the slurry and its optimal values for the manufacture of band-pass filters (BPF)

The object of research in this work were chosen two 4-shift filter on 2 resonator ceramic monoblocks, made by hot casting technology of ALTC ceramics. The main purpose of the work was determination of influence of additional grinding time on electrical parameters of BPF. The main criteria were chosen: further improvement of the squared-off ratio of BPF. Further work on the effect of density increase on electrical parameters of band-pass filter at the process stage of mass grinding is described. Results of sharper transition from bandwidth to suppression band and decrease of BPF rectangle coefficient are obtained. A version of further improvement of the technology of making ceramic housings for two-resonator monoblocks is proposed.

INVESTIGATION AND ASSESSMENT OF SOIL DENSITY CHANGED BY REPEATED PASSES OF MIDDLE-WEIGHT TRACTORS WITH DIFFERENT DRIVE SYSTEMS

This work presents the investigation of the influence of repeated passes of medium-weight tractors with single wheels and additional wheels on the soil density to the depth of 0.4 m. The experiments were carried out in the Greater Poland Region (Poland), on light soil (Luvisol, loamy sand). The soil density was analysed in the arable layer at the two depths of 0.08–0.12 m and 0.18–0.22 m and in the plough pan at a depth of 0.30–0.34 m. The tractors weighing 52.1, 62.8 and 71.8 kN equipped with single wheels (standard wheels) and tractors weighing 52.1 and 71.8 kN equipped with additional wheels were used in the experiments. The research proved that repeated passes of the tractors with standard and addition wheels caused a linear or non-linear (logarithmic) increase in the soil density in the arable layer. Only light tractor 52.1 kN with dual wheels caused soil density increase in the hard pen. The above soil density changes inconsistent depend on the weight tractors and mean tractor pressure. Repeated passes of tractors with additional wheels resulted in lower soil density in the arable layer especially by second and third pass. A larger number of passes of middle-weight tractors with standard wheels as well with additional wheels increases the risk of reduced yield of cultivated plants.