Biting force and physical fitness in athletes

The maximum biting force in 82 male athletes and 12 male subjects without any particular athletic activity (nonathletes) were measured in order to evaluate the relationship between biting force and physical fitness in athletes. The results obtained were as follows. 1. The maximum biting force in athletes (50.8 +/- 17.4kg) were significantly (p < 0.01) higher than that in the nonathletes (28.1 +/- 9.1kg). The maximum biting forces in the men who belonged to the rugby or judo clubs were predominantly higher than in other subjects. 2. In men who masticated on the left side of the mouth, the habitual (i. e., left) biting force was significantly higher than the nonhabitual (i. e., right) biting force. In men who masticated on the right side of the mouth, the habitual (i. e., right) biting force was also higher than the nonhabitual (i. e., left) biting force, but was not significantly so. 3. There was a significant positive correlation between the biting force and grip strength and back strength in athletes. In athletes, there was a significant correlation between biting force and the numbers of chin-ups, the numbers for the side-step tests and the time for 50m running.     

Heat transfer in a confined rectangular cavity packed with porous media

This paper presents an experimental investigation of convective heat transfer in a confined rectangular cavity packed with porous media, on the opposing vertical walls of which different temperatures are imposed. Measurements are made for each of two kinds of solid particles using three kinds of fluids, i.e. water, transformer oil and ethyl alcohol. The present experiments cover a wide range of Rayleigh number Ra1 between 1 and 10⁵, Prandtl number Pr1 between 1 and 200 and geometrical aspect-ratio $\text{H}\text{W}$ between 5 and 26. The experimental results indicate that Nusselt number Nu1 is correlated by the following relationship: $\text{Nu1 = 0.627 Pr1}{}^{0.130}\text{(}\text{H}\text{W}\text{)}{}^{\mathrm{?0.527}}\text{Ra1}{}^{0.463}$     

Cellular synergy in the manifestation of accessory cell activity for in vitro antibody response

The accessory cell (A-cell) activity of murine splenic adherent cells (SAC) and peritoneal exudate cells (PEC) for in vitro anti-SRBC and anti-DNP-KLH antibody responses of spleen lymphoid cells was abolished by the depletion of Ia+ cells from SAC and PEC by treatment with anti-Ia alloantiserum plus complement. The surviving Ia- macrophages in SAC and PEC were incompetent to achieve the A-cell activity. We prepared a crude and a further purified nonmacrophage cell fraction (termed CF and NMF). Nearly 70% of CF cells and more than 90% of NMF cells were Ia+ cells. The mature macrophage content of CF was less than 2%, and that of NMF was virtually negligible; suspected dendritic cells were contained at 5 to 10% in CF and 20 to 30% in NMF. The majority of cells in CF and NMF were lymphoid cells. This offered no problem in these experiments, since CF and NMF were added to lymphoid cells, in order to investigate the A-cell activity, usually in a ratio of 1 to 100. Neither CF nor NMF was adequate by itself to manifest the A-cell activity. However, the combination of either CF or NMF with Ia- macrophages resulted in the development of high A-cell activity. This did not occur with use of CF depleted of Ia+ cells or of NMF treated with anti-Ia without complement. These results indicated that the synergy between Ia- macrophages and Ia+ cells, most probably Ia+ nonmacrophage cells, was effective in developing the A-cell activity. It was also found that the interaction between the lymphoid cell and the Ia+ participant in the A-cell activity was genetically restricted, but Ia- macrophages functioned across the H-2 barrier.     

Experimental study on thermal properties of frozen soils

A series of measurements of the effective thermal conductivity, specific heat and unfrozen-water content of various soils exposed to a cold environment have been carried out by a transient probe method and a calorimetric technique. The present experiments were performed at a very slow rate of cooling of the moist-soil and using four kinds of soil samples from fine to coarse grain-size. It was established that the amount of unfrozen-water in the frozen soil was dependent on the initial moisture content, the grain-size of the soil and the temperature (below 0°C). Measured values of the effective thermal conductivity and specific heat show a strong dependence on temperature, initial moisture content and grain-size of soil in the temperature range T = 0°C to ?10°C. The anomalous behavior of a decrease in the effective thermal conductivity of frozen soil for the finest grain-size with decreasing temperature (below 0°C) was observed for a large initial moisture content w = 30–40%.     

Phase transitions in U3O8−z: I, heat capacity measurements

The heat capacity of U₃O_8−z with various O/U ratios was measured in the range from 250 to 750 K, and λ-type heat capacity anomalies were found in each sample. The transition temperatures were 487 and 573 K for UO_2.663, 490 and 576 K for UO_2.656 and 508, 562 and 618 K for UO_2.640. The entropy changes of the transitions were 0.44 and 0.39 J K⁻¹mol⁻¹ for UO_2.663, 0.58 and 0.47 J K⁻¹mol⁻¹ for UO_2.656 and 0.62, 0.51 and 0.25 J K⁻¹mol⁻¹ for UO_2.640, increasing as O/U decreases. The enthalpy change due to the transition varied linearly with the transition temperature except for UO_2.640, showing the presence of the same mechanism of phase transition among the samples with various O/U ratios. The mechanism of the phase transition was discussed on the assumption that the transition is originated from the order-disorder rearrangement of U⁵⁺ and U⁶⁺ with a consequent displacement of atoms, similarly to the case of U₄O_9−y.     

High-peak-power picosecond optical pulse generation from highly RF-modulated InGaAsP DH diode laser

The feasibility for generating high-peak-power ultrashort optical pulses was demonstrated from a highly RF-modulated InGaAsP DC-PBH laser diode at 1.3 ?m for the first time. Measured pulse width is found to be approximately 28 ps at 7 mW averaged output power, and peak output power reached about 1.2 W at 210 MHz repetition frequency. Higher peak output and shorter optical pulses could be expected with this type of semiconductor diode laser in the near-infra-red region.     

Surface temperature of Pd/C catalyst under microwave irradiation in dechlorination process of PCBs

In recent years, a new effective method of processing for polychlorinated biphenyls (PCBs) has been developed: It enables PCBs to become harmless by dechlorinating them using a 2.45 GHz microwave (MW). Compared with conventional thermal heating, MW processing hardly produces any harmful byproduct materials, and has high reaction velocity. To investigate such promotion of chemical reaction by MW irradiation, the surface temperature of the catalyst is measured by an infrared camera just after the irradiation by MW. It is recognized that there are some heated regions on the catalyst and the temperature is not uniform. It is natural to say that chemical reaction is promoted well on such a heated region. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Dielectrics loss of PCBs leading to microwave heating

A new effective processing for polychlorinated biphenyls (PCBs) has been recently developed. PCBs become harmless by dechlorination using 2.45 GHz-microwave (MW). To investigate such chemical reaction by MW irradiation, the dielectric loss of pure PCBs solutions and an isomer mixture in MW band is measured. Some PCBs and isopropyl alchol, added as a source of hydrogen supply have high dielectric loss in MW band. This suggests that MW heats PCBs and isopropyl alchol, and then the temperature of the solvent consisting mainly of insulating oil rises by the thermal conduction. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.