STUDY OF EFFECT OF SOLID CONTAMINANTS IN THE LUBRICANT ON BALL BEARINGS VIBRATION

In deep groove ball bearings contamination of lubricant grease by solid particles is one of the main reason for early bearing failure. To deal with such problem, it is fundamental not only the use of reliable techniques concerning detection of solid contamination but also the investigation of the effects of certain contaminant characteristics on bearing performance. Nowadays the techniques such as vibration measurements are being increasingly used for on-time monitoring of machinery performance. The present work investigates the effect of lubricant contamination by solid particles on the dynamic behavior of rolling bearings, in order to determine the trends in the amounts of vibration affected by contamination in the Grease and by the bearing wear itself. Experimental tests are performed with Deep-groove ball bearings. The Dolomite powder in three concentration levels and different particle sizes was used to contaminate the grease. Vibration signals were analyzed in terms of Root Mean Square (RMS) values and also in terms of defect frequencies

Clinico-social parameters of diabetes among patientsutilizing emergency medical services

Background: Diabetes mellitus (DM) is increasing in its potential in developing countries. Rise in diabetic patients calling emergency medical services (EMS) is expected. It calls for thorough assessment of patients with DM utilizing EMS. In the present study, was to assess magnitude of DM among patients utilizing EMS and its clinico-social parameters.Methods: It was hospital record based observational study of patients calling EMS delivered by a tertiary care hospital in Pune, Maharashtra, India during 1st January 2013 to 31st December 2014. Patients with incomplete records were excluded. A person with medical background was trained to extract required information from hospital records. Patients with previously diagnosed DM were considered those who were on diet, oral hypoglycemic agents or taking insulin therapy and newly diagnosed patients with DM were considered those with the value of glycemia on admission >200 mg/dl in first 24 hours. Data analysis was done using SPSS 15.0 software.Results: 45.8% (894/1951) were Patients with DM out of that 78.19% (699/894) were known to have DM while 28.81% (195/1951) were new cases of DM. 5.1% (100/1951) patients had uncontrolled DM. DM was significantly more in >60 years age group and in urban residents (p<0.001). Patients with DM were significantly more to have breathlessness, altered sensorium and dyspnoea as major purpose to call EMS (p<0.001, <0.001 and 0.045 respectively). Other co-morbidities in the form of Hypertension, other cardiovascular abnormalities, COPD, CKD and history of CVA were significantly more among Patients with DM (p<0.001, except for COPD, p=0.027).Conclusions: There was a high burden of patients with DM on EMS. EMS teams should be well trained to diagnose and manage such emergencies. Mass awareness of screening for DM and its proper management will help to decrease such burden

DESIGN AND ANALYSIS OF FEMORAL NAIL EXTRACTION INSTRUMENT FOR HUMAN FEMUR BONE

Different conventional techniques have been noticed to remove intramedullary femur distal nail, a simple method is explained to remove a broken distal closed section intramedullary nail with nail extraction instrument. The surgical technique is described. This technique reduces physical torture of patient during surgery and headache of doctors. In this article the design procedure for nail extraction instrument is explained as well as analysis results (in ANSYS) of nail extraction instrument are discussed. This technique involves removal of distal broken femur nail by on the spot creating threads in the nail, which is one of the feasible technique & the results of this analysis are helpful for orthopedic surgeons for clinical interest

Development of Aluminium Based Silicon Carbide Particulate Metal Matrix Composite for Spur Gear

AbstractMMCs are made by dispersing a reinforcing material into a metal matrix. They are prepared by powder metallurgy and casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite.The aluminum alloy composite materials consist of high strength, high stiffness, more thermal stability, more corrosion and wear resistance, and more fatigue life. aluminum alloy materials found to be the best alternative with its unique capacity of designing the materials to give required properties.In this work a composite is developed by adding silicon carbide in Aluminum metal by mass ratio 2.5%, 5%, 7.5% and 10%. The composite is prepared by stir casting technique. Mechanical tests such as hardness test, microstructure test are conducted. It is proposed to use this material for power transmitting elements such as gears which are subjected to continuous loading. Finally modeling and finite element analysis of gear is done using CATIA and ANSYS 14.0.In case of increased silicon carbide content, the hardness, and material toughness are enhanced. From the results it is concluded that composite material such as aluminum silicon carbide is one of the option as a material for power transmission gears

STUDY OF EFFECT OF SOLID CONTAMINANTS IN THE LUBRICANT ON BALL BEARINGS VIBRATION

In deep groove ball bearings contamination of lubricant grease by solid particles is one of the main reason for early bearing failure. To deal with such problem, it is fundamental not only the use of reliable techniques concerning detection of solid contamination but also the investigation of the effects of certain contaminant characteristics on bearing performance. Nowadays the techniques such as vibration measurements are being increasingly used for on-time monitoring of machinery performance. The present work investigates the effect of lubricant contamination by solid particles on the dynamic behavior of rolling bearings, in order to determine the trends in the amounts of vibration affected by contamination in the Grease and by the bearing wear itself. Experimental tests are performed with Deep-groove ball bearings. The Dolomite powder in three concentration levels and different particle sizes was used to contaminate the grease. Vibration signals were analyzed in terms of Root Mean Square (RMS) values and also in terms of defect frequencies.</jats:p

Investigation of grease lubricated deep groove ball bearing with multi-defected outer race using vibration signature analysis

Failure of any rotary machine is mainly due to bearing failure being the key element. Defect frequency is the function of speed, ball diameter, and pitch circle diameter of bearing. The number of defects does not affect the excitation frequency, but increase in the level of vibrations is observed in total. The inner race is mounted on the rotary shaft, and the outer race is fixed in the housing. Hence, a defect on the outer race does not rotate with the shaft. This article highlights the study of the multi-crack detection technique at a comparatively higher speed. Amplitudes of vibrations increase with speed, but with load, they almost remain the same. The experiment has been performed at the range from 1000 to 5000 r/min with 5 kg load on the test bearing. The location and size of the defect affect the level of vibrations with noticeable increase. However, the presence of a second defect with respect to the load zone plays an important role. As the defect is at the peak position in the load zone, outer race defect frequency excites more in the vibration spectra. The location and size of the second defect are varied, and acceleration amplitude parameters like RMS, peak, and peak to peak are compared. The current work emphasizes the effect of location and severity of the second defect on the vibration spectra and amplitude parameters of the vibrations. </jats:p