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)

Excellent electrical properties of TiO2/HfSiO/SiO2 layered higher-k gate dielectrics with sub-1 nm equivalent oxide thickness

Equivalent oxide thickness (EOT) scaling, as well as improved interface properties, of metal/higher- k gate stacks for the sub- 1 nm region was achieved using a TiO_2/HfSiO/SiO_2 layered dielectric structure. Ti diffusion into the bottom oxides was found to form electrical defects, which lead to an increase of leakage current, fixed charge, interface trap density (Dit), and reliability degradation of the gate stacks. By controlling Ti diffusion and terminating Ti-induced defects using forming gas annealing, we successfully obtained a superior interface property (Dit =9.9× 10^{10} eV^{-1} cm^{-2}) and reduced gate leakage (Jg =7.2× 10^{-2} A/cm^2) at the 0.71-nm -EOT region.Hiroaki Arimura, Naomu Kitano, Yuichi Naitou, Yudai Oku, Takashi Minami, Motomu Kosuda, Takuji Hosoi, Takayoshi Shimura and Heiji Watanabe, "Excellent electrical properties TiO_2/HfSiO/SiO_2 of higher-k gate dielectrics with sub-1nm equivalent oxide thickness", Appl. Phys. Lett. 92, 212902 (2008) https://doi.org/10.1063/1.292968

Impact of Gender on In-hospital Mortality in Patients with Acute Myocardial Infarction in Nagasaki

Acute myocardial infarction (AMI) is one of the leading causes of death in Japan. Immediate reperfusion therapy, includingcoronary intervention, improves patient prognosis. Despite this, females are said to be more prone to poor prognosis. A regional AMI registry in Nagasaki prefecture has been instituted recently that will evaluate whether female gender might predict short-term in-hospital death. Seventeen regional AMI centers enrolled all AMI patients from September 2014 through March 2016. A propensity score (PS) was derived using logistic regression to model the probability of females as a total function of the potential confounding covariates. Two types of PS techniques were used: PS matching and PS stratification. The consistency of in-hospital death was determined between PS matched patients of both genders. Based on PS, patients were ranked and stratified into five groups for the PS stratification. Out of 996 patients, 67 (6.7%) died during hospitalization: 31 (10.4%) out of 298 females and 36 (5.2%) out of 698 males (p < 0.0025). The proportion of cardiac and non-cardiac related death was almost same between genders (25 and 6 in female, 29 and 7 in male, respectively). Among 196 PS matched patients, there was a consistency between genders regarding in-hospital deaths (McNemar test, p = 0.6698). The 717 propensity scored patients had no significant differences between genders among propensity quintiles (Cochran-Mantel-Heanszel test, p = 0.7117). We found that gender alone is not an indicator of short-term in-hospital death in acute myocardial infarction patients

Arabic as a Jewish Language A Note on Similarities between Modern Hebrew and Modern Standard Arabic

This is a note or sketch on similarities between two Semitic languages: modern Hebrew and modern standard Arabic. They have a lot in common: triliteral structure of a word, conjugation, pronoun, etc. The two languages, however, have some striking differences: vocabulary, plural forms of nouns, syntactic structure like infinitive and subjunctive, etc.The author has pursued Amos Ozs literary works and his critical essays dealing with the current situations in Israel. In order to have comprehensive grasp of his world, it would be essential to know of the linguistic situation in Israel

Analysis of the Basic Spoken English Course at the University of Electro-Communications

Dual objectives of this paper are contained herein. The first is to familiarize its audience to the Basic Spoken English night course, a course offered by the Department of Human Communication at the University of Electro-Communications. Readers should get a general sense of understanding relevant to five main activities of this course, and see the significance of them pertinent to second language acquisition. The second function is that of reflection by the authors on the motives and intentions behind the activities, and critical analysis of these undertakings in a concerted effort to make improvements to future courses

Student Opinions and Attitudes toward the Use of Music in Learning English

Research in the area of music and its effects on learning has long established its value in education and specifically in language learning. Music adeptness has even been categorized as a major separate intelligence contrasting and complimenting the traditional concept of Logical/Mathematical Intelligence. However, most of the arguments for using music as a learning aid have come from scientists, researchers and instructors, and little has been done in the area of finding out student opinions and attitudes toward the use of music in the EFL/ESL classroom. Ascertaining these sentiments and dispositions is the aim of this study. Twenty-eight first-year Japanese university students attending the Basic Spoken English class at the University of Electro-Communications were asked what they thought about the use of music in learning English. Results indicate that the students, perhaps all of whom are unfamiliar with relevant formal research, appear to overwhelmingly agree with subject experts. This is not only a testament to the validity and value of previous research, but also to the future search for more effective methods of music use that can assist EFL/ESL learners

文体としての ≪名詞立て≫ ── 作家竹西寛子氏の散文を手がかりに ──

This paper discusses one characteristic aspect of the literary style found in critical works and essays of TAKENISHI Hiroko (1929 --), a distinguished novelist, literary critic and essayist. Among the typical examples is: ... koto eno kizuki wa daibu izen kara atta. (= there has long since been notice of the fact that ...) The use of a verbal noun “kizuki” (=notice) here is unusual, and a far more natural expression will be: ... koto ni watasi wa daibu izen kara kizuite ita. (= I have long since noticed that ...) TAkENISHI explores various uses of “nouns” in a most characteristic, impressive way, which contributes a great deal to producing an attractive literary style. This paper shows those various uses of “nouns”, and suggests that those uses be included in productive rhetorical Japanese expressions, which can be applied to non-literary prose as well

斉藤茂吉『万葉秀歌』と竹西寛子の散文に見られる、≪名詞立て≫に関するノート

This paper suggests the possibility that some uses of nouns and other expressions in a prose work by SAITO Mokichi, a celebrated Tanka poet, might have influenced the literary style of the prose of TAKENISHI Hiroki, a distinguished novelist, literary critic and essayist. Among the typical examples is: kodai nihonngo no yushu (= excellence of the ancient Japanese lanuguage) (M.SAITO) uta no dodo (= magnificence of the song) (H.TAKENISHI) The above suggestion comes from two observations: 1) The foregrounding of nouns shown above has seldom been used by most writers. 2) TAKENISHI wrote several times that she has been influenced by SAITO's analysis of ancient Japanese poems and by his literary style

柏崎驍二と本郷住枝の歌に学ぶ短歌技法

This article aims to help tanka-making beginners learn rhetorical expressions from tanka poems by KASHIWAZAKI Gyoji (1941-2016) and HONGO Sumie (1934-). The two poets learned the art of tanka from one of the major contemporary tanka poets: MIYA Shuji (1912-1986). The fact implies that the two poets learned from Miya some skills of making tanka. The characteristics of rhetorical expressions by the two poets are summarized as follows. The tanka poems by Kashiwazaki generally use plain expressions: they are mostly composed of plain vocabulary both in kango words, words made of Chinese characters and read in Chinese way, and wago words, original Japanese words. For example “地面” (jimen or ground) and “ちかづく” (chikazuku or coming nearer). Kashiwazaki avoids expressions not used in daily lives such as a compressed or shortened expression; for example 落ち実 (ochimi) or fallen fruit. Instead, he uses a natural phrase of 落ちた実 (ochita mi). Contrastively, Hongo makes use of strongly sounding kango such as 精魂 (seikon), meaning a steadfast will to realize something. She might have learned the use of this type of kango from Miya. Hongo also uses utakotoba, a word dominantly used in tanka, not in everyday life, such as kirigishi or a sharply cut cliff, and compressed or shortened expressions such as 熟実 (uremi) or ripe fruit. (“Uremi”, when heard, is difficult to understand, and should be “ureta mi” in daily communication.) The article suggests that shortened expressions by Hongo come from those by Miya. Learning the rhetorical expressions by the two poets, tanka beginners are expected to pursue useful rhetorical expressions for the tanka they would like to create