Inertia effect of textured lubricated contact on the bearing performance using CFD approach

Numerous studies reported that inertia of the lubricant has been considered as one of physical parameters which has a strong effect on the load support of textured bearing. In the present study, based on two-dimensional computational fluid dynamics (CFD) technique, the investigatation of the inertia effect on bearing performance is carried out varying the texture length. The Navier-Stokes equation coupled with the cavitation model are discretized using finite volume method and solved using the commercial software FLUENT®. The results show that the inertia increases the hydrodynamic film pressure and thus the load support. In addition, it is also found that increasing the texture length as well as Reynolds number will increase the cavitation region

Rancang Bangun Aplikasi Data Mining Analisis Tingkat Kelulusan Menggunakan Algoritma Fp-growth (Studi Kasus di Politeknik Negeri Malang)

Kondisi  kompetisi  dan  tuntutan  oleh  Direktorat  Jenderal  Pendidikan  (Dikti)  membuat  perguruan  tinggi harus memiliki keunggualan kompetitif dan kualitas agar dapat tetap bersaing dengan perguruan-perguruan tinggi lainnya. Teknologi informasi merupakan salah satu sumber daya yang dapat meningkatkan keunggulan bersaing dan dapat digunakan untuk mengolah informasi, menyebarkan informasi, serta pengambilan keputusan strategis. Tersedianya suatu informasi tidak terlepas dari melimpahnya data, dari pengolahan dan penggalian data tersebut informasi dapat diperoleh. Teknologi yang berkaitan dengan mengolah dan penggalian data menjadi informasi yang berguna adalah data mining. Teknologi data mining memiliki berbagai macam algoritma dan teknik untuk penyelesaian  masalah yang  berhubungan  dengan  data  salah  satunya  adalah  algoritma fp-growth dan  teknik association rules. Dari uraian diatas dapat dibuat sebuah aplikasi untuk menganalisis tingkat kelulusan melalui teknik  data  mining  menggunakan  algoritma fp-growth.  Informasi  yang  ditampilkan  menggunakan  teknik association rules yaitu menampilkan nilai support dan confidence dari masing-masing proses mining. Terbukti dari hasil pengujian yang dilakukan, algoritma fp-growth dan teknik association rules berjalan sesuai harapan dan dapat diimplemantasikan pada aplikasi data mining ini

Effect of inertia on the cavitation phenomena of hydrodynamic textured bearings considering slip

Surface modification of a lubricated bearing, such as hydrophobic coating inducing slip situation and texturing, is proved to enhance hydrodynamic performance. As widely known, in textured surface lubricant inertia and cavitation can significantly affect the hydrodynamic pressure profile. However, a brief literature review indicates that studies related to the correlation between cavitation and inertia, especially in the presence of slip, are considerably limited. The present study examines the effect of inertia on cavitation phenomena by considering the slip boundary using two approaches, namely computational fluid dynamics based on full Navier–Stokes equations and analytical lubrication equation based on the Reynolds equation. The modified Reynolds equation with slip concept is used with respect to the slip effect applied on the surface of the bearing. The results indicate that the inertia as well as the slip condition significantly affects the cavitation area. It is also highlighted that the cavitation area reduces by increasing the inertia effect, and it becomes smaller when the slip is introduced

CFD analysis of texture depth effect on the performance of hydrodynamic lubricated bearing

Surface modification of the lubricated bearing such texturing has proven to improve the hydrodynamic performance. The present paper examined the effect of texture depth as well as the texture length on the tribological performance using computational fluid dynamic (CFD) approach. The cavitation model was also considered to obtain more realistic characteristic of bearing. It was shown that by increasing texture depth of the surface of bearing, the enhanced hydrodynamic pressure was achieved. Moreover, other interesting result is that the length of cavitation region decreases with the increase in texture depth and the decrease in texture length

Indentation Mechanism in Rotary Hammer Forging Process: Analytical and Numerical Approach

Rotary hammer forging process is getting popular since it has many advantages comparing to the conventional forging process. The mechanism of the movement in term of orbital motion of the conical upper die become concern of this research. This article present the three stages of the modelling of the rotary hammer forging. The first stage is the development of the orbital motion of the conical upper die. Three-dimensional CAD model of the conical upper die was developed to determine the orbital motion as a function of the four parameters: Nutation, Precession, Spin and Rocking-Die mechanism. A reasonably accurate design of the conical upper die and the workpiece had been developed based on motion because of interaction of conical upper die and upper part of workpiece geometries. The behaviour of orbital motion with any active combination of those four parameters was observed. The second stage was the development of the conical upper die with the specific feature in order to generate a product with an unsymmetrical shape of upper part of the product. The sequence and mechanism of the formation of the upper part of product were generated. The third stage was the analysis of the stress strain state during the formation of the upper part of the workpiece. An elastic-plastic, dynamic analysis of 3D rotary hammer forging mechanism with the concern at the workpiece and their interaction with a model of dies have been performed. Verification of the indentation mechanism of the rotary hammer forging had been done by validating the result with the existing experimental results

The relationship between the systemic inflammatory response and survival in patients with transitional cell carcinoma of the urinary bladder

The relationship between tumour stage, grade, elevated C-reactive protein concentration (<10/>10 mg l−1), adjuvant therapy and survival was examined in patients with biopsy proven bladder cancer (n=105). On multivariate analysis stage (HR 3.37, 95% CI 1.37–8.29, P=0.008), grade (HR 2.01, 95% CI 1.14–3.57, P=0.017) and preoperative C-reactive protein (HR 3.31, 95% CI 1.09–10.09, P=0.035) were independently associated with cancer-specific survival

The relationship between the systemic inflammatory response, tumour proliferative activity, T-lymphocytic infiltration and COX-2 expression and survival in patients with transitional cell carcinoma of the urinary bladder

The relationship between the systemic inflammatory response, tumour proliferative activity, T-lymphocytic infiltration, and COX-2 expression and survival was examined in patients with transitional cell carcinoma of the urinary bladder (n=103). Sixty-one patients had superficial disease and 42 patients had invasive disease. Cancer-specific survival was shorter in those patients with invasive compared with superficial bladder cancer (P<0.001). On univariate analysis, stratified by stage, increased Ki-67 labelling index (P<0.05), increased COX-2 expression (P<0.05), C-reactive protein (P<0.05) and adjuvant therapy (P<0.01) were associated with poorer cancer-specific survival. On multivariate analysis of these significant factors, stratified by stage, only C-reactive protein (HR 2.89, 95% CI 1.42–5.91, P=0.004) and adjuvant therapy (HR 0.29, 95% CI 0.14–0.62, P=0.001) were independently associated with poorer cancer-specific survival. These results would suggest that tumour-based factors such as grade, COX-2 expression or T-lymphocytic infiltration are subordinate to systemic factors such as C-reactive protein in determining survival in patients with transitional cell carcinoma of the urinary bladder

The relationship between the preoperative systemic inflammatory response and cancer-specific survival in patients undergoing potentially curative resection for renal clear cell cancer

The relationship between tumour stage, grade (Fuhrman), performance status (ECOG), a combined score (UCLA Integrated Staging System, UISS), systemic inflammatory response (elevated C-reactive protein concentration), and cancer-specific survival was examined in patients undergoing potentially curative resection for renal clear cell cancer (n=100). On univariate survival analysis, sex (P=0.050), tumour stage (P=0.001), Fuhrman grade (P<0.001), UISS (P<0.001), C-reactive protein (P=0.002) were significant predictors of survival. On multivariate analysis with sex, UISS and C-reactive protein entered as covariates, only UISS (HR 2.70, 95% CI 1.00–7.30, P=0.050) and C-reactive protein (HR 4.00, 95% CI 1.21–13.31, P=0.024) were significant independent predictors of survival. The presence of a preoperative systemic inflammatory response predicts poor cancer-specific survival in patients who have undergone potentially curative resection for renal clear cell cancer

An elevated C-reactive protein concentration, prior to surgery, predicts poor cancer-specific survival in patients undergoing resection for gastro-oesophageal cancer

There is increasing evidence that the presence of an ongoing systemic inflammatory response is associated with poor outcome in patients undergoing resection for a variety of tumours. The aim of the present study was to examine the relationship between clinico-pathological status, preoperative C-reactive protein concentration and cancer-specific survival in patients undergoing resection for gastro-oesophageal cancer. One hundred and twenty patients attending the upper gastrointestinal surgical unit in the Royal Infirmary, Glasgow, who were selected for potentially curative surgery, were included in the study. Laboratory measurements of haemoglobin, white cell, lymphocyte and platelet counts, albumin and C-reactive protein were carried out at the time of diagnosis. All patients underwent en-bloc resection with lymphadenectomy and survived at least 30 days following surgery. On multivariate analysis, only the positive to total lymph node ratio (hazard ratio (HR) 2.02, 95% confidence interval (CI) 1.44–2.84, P<0.001) and preoperative C-reactive protein concentration (HR 3.53, 95% CI 1.88–6.64, P<0.001) were independent predictors of cancer-specific survival. The patient group with no evidence of a preoperative systemic inflammatory response (C-reactive protein ⩽10 mg l−1) had a median survival of 79 months compared with 19 months in the elevated systemic inflammatory response group (P<0.001). The results of the present study indicate that in patients selected to undergo potentially curative resection for gastro-oesophageal cancer, the presence of an elevated preoperative C-reactive protein concentration is an independent predictor of poor cancer-specific survival