Development of Rotary Compressor for High-efficiency CO2 Heat-pump Hot-Water Supply System

In Japan, there has been an increase in the use of domestic heat-pump hot-water supply systems in which the refrigerant is CO2, which does not cause ozone layer depletion and has a low global-warming potential. In addition, in recent years, there has been an increase in the number of examples in which CO2 is employed as a refrigerant for showcase refrigerators, freezers etc. Therefore, in the future, it is expected that there will be an increasing demand for CO2 compressors with greater efficiency and lower noise. In the case of domestic heat-pump hot-water supply systems, in order to increase the annual performance factor (APF) of a product, it is effective to enhance the coefficient of performance (COP) in an intermediate capacity range. Here, we report the development of a high-APF rotary compressor achieved by optimizing the design specifications of a motor and a discharge pathway from a discharge chamber, for operation in the intermediate capacity range. In the optimization process, in order to cope with the high operating pressure of the CO2 water-heating cycle, we performed analysis using the finite element method (FEM) for evaluating the stiffness around the discharge port. In addition, we used an FEM model of the entire compressor in a modal analysis, and, in analyzing the radiation surfaces of the rotary compressor, we used an acoustic particle velocity probe that is capable of measuring the intensity at an intermediate portion between the accumulator and the compressor main unit, where it has been difficult to take measurements in the past. We also discuss an example in which noise reduction was confirmed when the specifications of the accumulator were changed based on the results of these analyses

Proposal for realizing quantum spin models with Dzyaloshinskii-Moriya interaction using Rydberg atoms

We propose a method to realize tunable quantum spin models with Dzyaloshinskii-Moriya interaction (DMI) in Rydberg atom quantum simulators. Our scheme uses a two-photon Raman transition and transformation to the spin-rotating frame. We investigate the quantum dynamics of the model including only the DMI and Zeeman energy, which can be experimentally realized in our scheme. Unlike its classical counterpart, the magnetization curve in this model is continuous under the open boundary condition. We also show that the model accommodates quantum many-body scars exhibiting nonergodic dynamics.Comment: 7 pages and 4 figures (main) and 13 pages, 8 figures, and 1 table (supple

Direct Pulp Capping Effect with Experimentally Developed Adhesive Resin Systems Containing Reparative Dentin Promoting Agents on Rat Pulp -Mixed Amounts of Additives and Their Effect on Wound Healing-

This study examined the wound healing process of exposed rat pulp when treated with experimental adhesive resin systems. The experimental direct pulp capping adhesive resin systems were composed of primer-I, primer-II and an experimental bonding agent. Primer-I was Clearfil SE Bond (CSE) primer containing 1.0 or 5.0wt% CaCl2, and primer-II was CSE primer containing 0.1, 1.0 or 5.0wt% compound of equal mole of pA and pB with synthetic peptides derived from dentin-matrix-protein 1 (DMP1). Primer-I containing 1.0wt% and 5.0wt% CaCl2 were assigned to the experimental groups 1 to 3, and 4 to 6, respectively. Primer-II containing 0.1, 1.0 or 5.0wt% compound of pA and pB were assigned to the experimental groups 1 and 4, 2 and 5, and 3 and 6, respectively. In all experimental groups, CSE bond containing 10wt% hydroxyapatite powder was used as the experimental bonding agent. The positive control teeth were capped with calcium hydroxide preparation (Dycal), and the negative control teeth were capped with CSE. The specimens were alternately stained with Mayer's H&E and the enhanced polymer one-step staining method. Experimental groups 1, 4, 5 and 6 showed a higher level of reparative dentin formation compared to the negative control 14 days postoperatively. At 28 days postoperatively, all experimental groups showed the formation of extensive reparative dentin, and experimental groups 4, 5 and 6 demonstrated similar dentin bridge formation as that of the positive control. How quickly reparative dentin formation occurs might depend on the concentration of CaCl2 and pA and pB in the experimental primer

Effect of Light-Emitting Diode (Led) Light on the Gene Expression Related With Ascorbate Biosynthesis and Metabolism in Broccoli Florets

Ascorbate is one of the most abundant soluble antioxidants in the plant. Multiple functions of ascorbate in photo protection have been proposed, including scavenging of reactive oxygen species generated by oxygen photoreduction and photorespiration. There is still unclear information relation to LED light with Ascorbate biosynthesis and metabolism, yellowing, chlorophyll content, and ethylene production in broccoli florets. The effect of light-emitting diodes (LED) light on ascorbate (AsA) biosynthesis and metabolism in broccoli (Brassica oleracea L. var. Italica) cultivar “Ryokurei” were studied using red (660 nm), blue (470 nm) and white LED lights as the light source and also no light treatment as the control. Gene expression involved in the biosynthesis and metabolism of AsA, AsA content, color, chlorophyll content and ethylene production rate on the postharvest broccoli were observed in 4 days. The result showed that after two days, red light treatment significantly (p < 0,05) delayed the decrease of ascorbate content. The result was supported by observations using Real-Time Quantitative RT-PCR showed that red light treatment can suppress mRNA level of BO-APX1, BO-APX2, and BO-sAPX on the third day. Observation of BO-GLDH mRNA level was increased in the third-day exposure of red LED light. Therefore red LED light showed up-regulated AsA biosynthesis transcriptional level. Enzymes which possibility responsible for AsA metabolism and biosynthesis in a row were Ascorbate Peroxide (APX) and L-Galactono-1,4-Lactone Dehydrogenase (GLDH). The regulation of this gene expression might contribute to the suppression of AsA reduction by red LED light treatment in broccoli. Red LED also showed suppression of yellowing and decline the chlorophyll content in postharvest broccoli florets. Keywords: ascorbate, LED; broccoli; gene expression; real-time quantitative RT-PCR

Enhancement of protein thermostability by three consecutive mutations using loop-walking method and machine learning

We developed a method to improve protein thermostability, "loop-walking method". Three consecutive positions in 12 loops of Burkholderia cepacia lipase were subjected to random mutagenesis to make 12 libraries. Screening allowed us to identify L7 as a hot-spot loop having an impact on thermostability, and the P233G/L234E/V235M mutant was found from 214 variants in the L7 library. Although a more excellent mutant might be discovered by screening all the 8000 P233X/L234X/V235X mutants, it was difficult to assay all of them. We therefore employed machine learning. Using thermostability data of the 214 mutants, a computational discrimination model was constructed to predict thermostability potentials. Among 7786 combinations ranked in silico, 20 promising candidates were selected and assayed. The P233D/L234P/V235S mutant retained 66% activity after heat treatment at 60 degrees C for 30 min, which was higher than those of the wild-type enzyme (5%) and the P233G/L234E/V235M mutant (35%)