Compressor with Turning-Paired Vane and Piston

With the aim of energy saving of room air conditioners, we are addressing higher efficiency of the rotary compressor that is used most in the world. We focused on a new rotary compressor equipped with a mechanism to restrict the rolling motion of the piston, and performed the dynamics analysis. The new rotary compressor has a small pillar at the tip of the vane and constitutes a turning pair of vane and piston, and it limits the rolling motion of the piston. By means of limiting the piston rotation, the heat transfer to the suction process from the compression chamber will be suppressed, and we can expect higher compression efficiency. Before examining the compression efficiency, we performed the dynamics analysis of this new rotary compressor and examined the forces and dynamic behavior of the components, and the mechanical efficiency of the compressor. Then we have following results. (1)We can clarify the contact point between the vane tip and piston in the turning pair by considering the equilibrium of forces and moments acting on the vane. (2)By reducing the diameter of the pillar at the vane tip, the vane tip friction loss is reduced, and the mechanical efficiency is improved. (3)The new rotary compressor has less vane tip friction loss and on the other hand greater friction loss between the vane side and the cylinder in comparison to the rolling piston rotary compressors. As a result, both compressors have almost the same mechanical efficiency

Hydrodynamic-Pressure-Induced Elastic Deformation of Thrust Slide-Bearings in Scroll Compressors and Oil Film Pressure Increase Due to Oil Envelopment

This paper presents the concept of the Elasto-Hydrodynamic Lubrication?EHL?of thrust slide-bearings in scroll compressors, resulting in the superior lubrication characteristics of these bearings. The thrust plate undergoes elastic deformation due to axial loading, resulting in the formation of a uniform fluid wedge between the orbiting and fixed thrust plates. This wedge region has very high induced oil film pressure, which explains the remarkably good lubrication characteristics of the thrust slide-bearing. Furthermore, the high oil film pressure induces further local elastic deformation of the thrust plate, forming an EHL oil pocket with the thrust plate and a further increase in the oil film pressure between the sliding surfaces due to this oil envelopment. The formation of the EHL pocket was confirmed using FEM analysis and lubrication tests on the elastic deformation of the thrust plate. Subsequently, the additional increase in oil film pressure, due to the EHL pocket effect, was examined in computer simulations applying the average Reynolds equation for the boundary of elastic deformation of the thrust plate. In these studies, a 6.7% increase in oil film pressure was ascertained for a small cooling capacity scroll compressor driven at 3600 rpm with 0.1 kW motor. The oil envelopment contributes to the superior lubrication performance of the thrust slide bearings scroll compressors

Optimization of EHL Lubrication Performance in Thrust Slide-Bearings of Scroll Compressors

Previous studies [Refs. 1, 2] revealed the formation of a uniform oil wedge at the periphery of the thrust plate, caused by the elastic deformation of the orbiting thrust plate due to the pressure difference across the orbiting thrust plate, is a significant factor in the high lubrication performance in thrust slide-bearings. In addition to the uniform wedge formation, the high oil film pressure also induces a local elastic deformation of the fixed thrust plate normal to its surface. The normal thrust plate deformation and the oil wedge effectively form an elasto-hydrodynamic-lubrication (EHL) pocket, even more effectively increasing the oil film pressure between the sliding surfaces, due to the envelopment of the oil, as confirmed in our companion paper [3], and an earlier, less-detailed contribution [4]. The present study focuses on aspects of EHL that have both positive and negative effects on the lubrication performance of the thrust slide-bearings in scroll compressors. Theoretical calculations using the average Reynolds equation and Patier-Chen solid contact theory, for the boundary of the local elastic deformation of the thrust slide-bearing, were conducted for a small cooling capacity scroll compressor driven at 3600 rpm with 0.1 kW. An approximate method was developed using characteristic curves to determine the oil film axial force, the average oil film thickness, the frictional force and the frictional coefficient. The calculations considered a variety of pressure differences due to the operation pressure and the thickness of thrust plate. Also cases with a fixed uniform wedge angle at the periphery were calculated. The calculated results suggest a possible maximum reduction in frictional coefficient of about 55% compared to that with a fixed uniform wedge angle. The reduction rate increases with decreasing thrust plate thickness, which, however, restricts the operation pressures to a lower pressure range. Design guidelines for optimizing EHL will be suggested. References: [1] Oku, T., Ishii, N., Anami, K., Knisely, C.W., Sawai, K., Morimoto, T., Hiwata, A. : Theoretical Model of Lubrication Mechanism in the Thrust Slide-Bearing of Scroll Compressors, HVAC&R Research Journal ASHRAE Vol.14, No.2, pp.239-358, 2008-3. [2] Ishii, N., Oku, T., Anami, K., Knisely, C.W., Sawai, K., Morimoto, T., Iida, N. : Experimental Study of the Lubrication Mechanism for Thrust Slide Bearings in Scroll Compressors, HVAC&R Research Journal ASHRAE Vol.14, No.2, 2008-4. [3] Ishii, N., Tsuji, T., Anami, K., Nokiyama, K., Morimoto, T., Sakuda, A., Oku, T., Sawai, K., Knisely, C.W., : “Hydrodynamic-Pressure-Induced Elastic Deformation of Thrust Slide-Bearings in Scroll Compressors and Oil Film Pressure Increase Due to Oil Envelopment,” abstract submitted to 2014 Purdue Herrick Conferences. [4] Ishii, N., Tsuji, T., Oku, T., Anami, K., Knisely, C.W., Nokiyama, K., Morimoto, T., Sakuda, A., Sawai, K. 2012 “Elasto-Hydrodynamic Lubrication Effect in Thrust-Slide Bearings of Scroll Compressors,” 2012 Purdue Conference Paper on (Paper 1438)

Use of the index of pulmonary vascular disease for predicting long-term outcome of pulmonary arterial hypertension associated with congenital heart disease

AimsLimited data exist on risk factors for the long-term outcome of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD-PAH). We focused on the index of pulmonary vascular disease (IPVD), an assessment system for pulmonary artery pathology specimens. The IPVD classifies pulmonary vascular lesions into four categories based on severity: (1) no intimal thickening, (2) cellular thickening of the intima, (3) fibrous thickening of the intima, and (4) destruction of the tunica media, with the overall grade expressed as an additive mean of these scores. This study aimed to investigate the relationship between IPVD and the long-term outcome of CHD-PAH.MethodsThis retrospective study examined lung pathology images of 764 patients with CHD-PAH aged <20 years whose lung specimens were submitted to the Japanese Research Institute of Pulmonary Vasculature for pulmonary pathological review between 2001 and 2020. Clinical information was collected retrospectively by each attending physician. The primary endpoint was cardiovascular death.ResultsThe 5-year, 10-year, 15-year, and 20-year cardiovascular death-free survival rates for all patients were 92.0%, 90.4%, 87.3%, and 86.1%, respectively. The group with an IPVD of ≥2.0 had significantly poorer survival than the group with an IPVD <2.0 (P = .037). The Cox proportional hazards model adjusted for the presence of congenital anomaly syndromes associated with pulmonary hypertension, and age at lung biopsy showed similar results (hazard ratio 4.46; 95% confidence interval: 1.45–13.73; P = .009).ConclusionsThe IPVD scoring system is useful for predicting the long-term outcome of CHD-PAH. For patients with an IPVD of ≥2.0, treatment strategies, including choosing palliative procedures such as pulmonary artery banding to restrict pulmonary blood flow and postponement of intracardiac repair, should be more carefully considered

白血病細胞のアポトーシスにおけるセラミドの役割

京都大学0048新制・課程博士博士(医学)甲第6747号医博第1847号新制||医||658(附属図書館)15819UT51-97-H131京都大学大学院医学研究科内科系専攻(主査)教授 野田 亮, 教授 永田 和宏, 教授 大熊 稔学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Induction of Apoptosis in TNF-Treated L929 Cells in the Presence of Necrostatin-1

It has been shown that necroptosis—caspase-independent programmed necrotic cell death—can be induced by treatment with tumor necrosis factor (TNF) in the L929 murine fibrosarcoma cell line, even in the absence of a caspase inhibitor. Although it was reported that necrostatin-1—a specific inhibitor of necroptosis—inhibited TNF-induced necroptosis in L929 cells, it has not been elucidated whether the cells eventually die by apoptosis in the presence of necrostatin-1. In this paper, induction of apoptosis was demonstrated in TNF-treated L929 cells in the presence of necrostatin-1. Co-treatment with cycloheximide expedited apoptosis induction in necrostatin-1/TNF-treated L929 cells: typical apoptotic morphological changes, including membrane blebbing and nuclear fragmentation, induction of caspase-3 activity, proteolytic activation of caspases-3, -8, and -9, and cleavage of poly(ADP-ribose) polymerase (PARP) (a well-known substrate of caspase-3) were observed. Moreover, co-treatment with Z-VAD-fmk (a pan-caspase inhibitor) inhibited apoptosis by completely inhibiting caspases, resulting in a shift from apoptosis to necroptosis. In contrast, co-treatment with Z-Asp-CH2-DCB (a caspase inhibitor preferential to caspase-3) inhibited apoptosis without expediting necroptosis. These results indicate that apoptosis can be induced in TNF-treated L929 cells when the cells are protected from necroptosis, and support the notion that partial activation of caspase-8 in the presence of a caspase inhibitor preferential to caspase-3 suppresses both apoptosis and necroptosis