A coupled finite-volume CFD solver for two-dimensional elasto-hydrodynamic lubrication problems with particular application to rolling element bearings

This paper describes a new computational fluid dynamics methodology for modelling elastohydrodynamic contacts. A finite-volume technique is implemented in the ‘OpenFOAM’ package to solve the Navier-Stokes equations and resolve all gradients in a lubricated rolling-sliding contact. The method fully accounts for fluid-solid interactions and is stable over a wide range of contact conditions, including pressures representative of practical rolling bearing and gear applications. The elastic deformation of the solid, fluid cavitation and compressibility, as well as thermal effects are accounted for. Results are presented for rolling-sliding line contacts of an elastic cylinder on a rigid flat to validate the model predictions, illustrate its capabilities, and identify some example conditions under which the traditional Reynolds-based predictions deviate from the full CFD solution

Heat flux evaluation in high temperature ring-on-ring contacts

A comprehensive methodology to investigate heat flux in a ring-on-ring tribometer is presented. Thermal fluxes under high contact pressures and temperature differences were evaluated through an experimental campaign and by a numerical procedure of inverse analysis applied to surface temperature measurements. An approximation of a two-dimensional time-dependent analytical solution for the temperature distribution was first developed and subsequently adapted to mimic the specific testing configuration characteristics; the problem was finally simplified to enable further inverse analysis. Experiments were performed using an innovative high temperature ring-on-ring tribometer. The evaluated contact heat transfer rates were reported as a function of normal load and temperature difference between the discs under steady-state conditions; the results reported here show that, in the present test configuration, the temperature difference has stronger influence than the applied load in terms of heat transfer induced by contact

The influence of the preparation method of NiOx photocathodes on the efficiency of p-type dye-sensitised solar cells

Improving the efficiency of p-type dye-sensitized solar cells (DSCs) is an important part of the development of high performance tandem DSCs. The optimization of the conversion efficiency of p-DSCs could make a considerable contribution in the improvement of solar cells at a molecular level. Nickel oxide is the most widely used material in p-DSCs, due to its ease of preparation, chemical and structural stability, and electrical properties. However, improvement of the quality and conductivity of NiO based photocathodes needs to be achieved to bring further improvements to the solar cell efficiency. The subject of this review is to consider the effect of the preparation of NiO surfaces on their efficiency as photocathodes. (C) 2015 Elsevier B.V. All rights reserved

Sindrom Geriatri (Imobilitas, Instabilitas, Gangguan Intelektual, Inkontinensia, Infeksi, Malnutrisi, Gangguan Pendengaran)

Latar Belakang. Sindrom geriatri adalah serangkaian kondisi klinis pada orang tua yangdapat mempengaruhi kualitas hidup pasien dan dikaitkan dengan kecacatan. Tampilanklinis yang tidak khas sering membuat sindrom geriatri tidak terdiagnosis. Kasus. Tn. H,80 tahun, datang dengan keluhan sesak nafas yang baru pertama kali dialami.Inkontinensia alvi, inkontinensia urin, demensia, dan sulit berjalan sudah dirasakan pasiendalam 3 bulan. Dua hari sebelum masuk rumah sakit, pasien terjatuh dari kursi karenakondisi pasien yang lemah. Tidak ada riwayat khusus tentang penyakit yang pernahdialami pasien. Kesadaran compos mentis dengan tekanan darah 140/80 mmHg. Padaekstremitas bawah terdapat edema non pitting. Pemeriksaan laboratorium didapatkan Hb:11.5 g/dl, Ht : 35.6%, Albumin: 2.55, Serum Glutamic Oxaloacetic Transaminase: 84.3,Serum Glutamic Pyruvic Transaminase : 120.7, Ureum: 134.6, Kreatinin: 3.40.Penatalaksanaan pasien dilakukan berdasarkan prinsip pengobatan pada geriatri.Simpulan: Sindrom geriatri adalah suatu kondisi klinis, bukan penyakit. Sindrom geriatrimerupakan gabungan antara penurunan fisiologik dan berbagai proses patologik.[Medula Unila.2013;1(3):117-125

Hubungan Kematangan Emosi Dan Kebahagiaan Pada Remaja Yang Mengalami Putus Cinta

Salah satu tugas perkembangan remaja adalah mulai mengenal lawan jenis dan jatuh cinta. Berbicara mengenai jatuh cinta pasti juga akan berbicara mengenai putus cinta. Menurut data statistic ditemukan factor utama yang menjadi alasan remaja bunuh diri adalah masalah percintaan. Oleh karena itu para remaja perlu memiliki kematangan emosi yang baik sebelum memutuskan untuk berpacaran karena dengan kematangan emosi yang baik remaja akan mampu mengendalikan segala bentuk emosi negatif yang muncul setelah berpisah dari mantan pacar dan mengedepankan emosi positif yang mampu memicu timbulnya kebahagiaan. Populasi dalam penelitian ini merupakan remaja dengan kategori usia 17-21 tahun yang pernah putus cinta maksimal 2 tahun yang lalu dengan jumlah sampel sebanyak 84 responden. Teknik analisis data yang digunakan adalah korelasi Product Moment Pearson dengan koefesien sebesar 0.721 dan P= 0,000 (p<0,05). Hasil penelitian menunjukkan bahwa ada hubungan yang sangat signifikan dengan arah hubungan positif antara kematangan emosi dan kebahagiaan pada remaja yang mengalami putus cinta, bahwa semakin tinggi kematangan emosi maka akan semakin tinggi pula kebahagiaan dan semakin rendah kematangan emosi maka akan semakin rendah kebahagiaan pada remaja yang mengalami putuscinta

Weight Loss Supplements

: Being overweight or obese can predispose people to chronic diseases and metabolic disorders such as cardiovascular illnesses, diabetes, Alzheimer’s disease, and cancer, which are costly public health problems and leading causes of mortality worldwide. Many people hope to solve this problem by using food supplements, as they can be self-prescribed, contain molecules of natural origin considered to be incapable of causing damage to health, and the only sacrifice they require is economic. The market offers supplements containing food plant-derived molecules (e.g., primary and secondary metabolites, vitamins, and fibers), microbes (probiotics), and microbial-derived fractions (postbiotics). They can control lipid and carbohydrate metabolism, reduce appetite (interacting with the central nervous system) and adipogenesis, influence intestinal microbiota activity, and increase energy expenditure. Unfortunately, the copious choice of products and different legislation on food supplements worldwide can confuse consumers. This review summarizes the activity and toxicity of dietary supplements for weight control to clarify their potentiality and adverse reactions. A lack of research regarding commercially available supplements has been noted. Supplements containing postbiotic moieties are of particular interest. They are easier to store and transport and are safe even for people with a deficient immune system