Arvind Kumar Singh

Prevalence of Osteoarthritis of Knee Among Elderly Persons in Urban Slums Using American College of Rheumatology (ACR) Criteria.

BACKGROUND The prevalence of osteoarthritis among elderly is high and it majorly affects the quality of life. Knee osteoarthritis is the most common form of osteoarthritis. Timely diagnosis using clinical criteria and effective intervention is of utmost importance. AIM To estimate the prevalence and determinants of osteoarthritis of knee joint among elderly persons residing in an urban slum of Delhi using ACR clinical criteria. MATERIALS AND METHODS We did a community-based cross-sectional study among 496 elderly (>= 60 years) persons residing in urban slum of Delhi, India from December 2009 to February 2010. The American College of Rheumatology (ACR) criteria was used to clinically diagnose osteoarthritis knee. STATISTICAL ANALYSIS Bivariate analysis using Chi-square test and multivariate analysis was done to identify the determinants. Sensitivity and specificity of individual factors to diagnose osteoarthritis knee was calculated. RESULTS The prevalence of osteoarthritis was estimated to be 41.1% (95% C.I., 36.7-45.6). Female sex and age >= 70 y were found to be independent risk factor for osteoarthritis knee. Among those having knee pain, presence of crepitus and tenderness were the most sensitive factors whereas bone overgrowth and bone warmth were most specific factors. CONCLUSION The prevalence of osteoarthritis knee was high among this elderly population and increased with age. Overall, individual factors of ACR criteria were both sensitive and specific in diagnosing osteoarthritis knee. In resource constrained setting of urban India, it can be an effective tool in clinical diagnosis of osteoarthritis knee.

Assessment and control of ignition risk of HT induction motor for increased safety Ex ‘e’ as per Indian standard for explosive atmospheres

It is very difficult to manage ignition risk by operational procedures to ensure that there has not been a hazard gas release in the area prior to starting the motor or and stator sparking which may occur during running; this procedure may be less appropriate than an automatic interlock. As per Indian Standard rotor cage potential sparking and potential stator winding discharge of induction motor are to be considered for risk assessments of increased safety motor. Risk assessment is done based on construction, operation, protection, and environmental conditions of the motor and ignition risk factor are assigned based on its characteristics. The sum of assigned risk factors should not be more than 5. If it is greater than 5 the motor should be type tested where no incendive sparking should occur during ignition risk assessment test for Ex ‘e’ motor. The paper discuses about the control of ignition risk and assessment of risk factor. The paper also describes the ignition risk assessments test of HT (High Tension) Ex ‘e’ motor as per Indian Standard, conducted successfully first time in India by Central Institute of Mining and Fuel Research Institute (CIMFR), Dhanbad jointly with Bharat Heavy Electricals Limited, India.

Thin epitaxial silicon PIN detectors for thermal neutron detection with improved gamma (γ) discrimination

In order to improve the gamma discrimination capability for thermal neutron measurements using silicon PIN detectors, a novel approach of use of thin epitaxial silicon PIN detectors was investigated. Thin epitaxial silicon detectors with thickness of 15 µm were developed and their performance was tested with thermal neutrons using 10B converter. The performance of this detector was compared with the performance of a 300 µm silicon detector. The results of experiments presented in this paper indicate that thin epitaxial silicon detectors can significantly improve γ discrimination for thermal neutron measurements.

Gamma response study of radiation sensitive MOSFETs for their use as gamma radiation sensor

Continuous monitoring of gamma dose is important in various fields like radiation therapy, space-related research, nuclear energy programs and high energy physics experiment facilities. The present work is focused on utilization of radiation-sensitive Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) to monitor gamma radiation doses. Static characterization of these detectors was performed to check their expected current-voltage relationship. Threshold voltage and transconductance per unit gate to source voltage (K factor) were calculated from the experimental data. The detector was exposed to gamma radiation in both, with and without gate bias voltage conditions, and change in threshold voltage was monitored at different gamma doses. The experimental data was fitted to obtain equation for dependence of threshold voltage on gamma dose. More than ten times increase in sensitivity was observed in biased condition (+3 V) compared to the unbiased case.

Structure and Magnetic Properties Investigation of CoZr and CoZrN Thin Films

nanocomposite [(Co91.5Zr8.5)- or CZN films has been prepared by reactive co-sputter deposition method. Nitrogen content plays key role to tune soft magnetic properties. Experimental observation shows that, non-magnetic nitrogen content enhances magnetization and reduces coercivity. The nanostructure is composed of Co nanoclusters embedded in CoN/ZrN matrix, revealed by high resolution transmission electron microscope study. The d-spacing of single Co nanocluster was found to be ~0.22nm corresponding to (002) phase of Cobalt. X-ray diffraction result is in agreement with cubic (400) and (622) phase of CoZr. High electrical resistivity ρs~108μΩ-cm attained corresponding to 16% N2 content films. Hysteresis loop squareness depends on film thickness and coercivity squareness (S*)~0.84, obtained for ~250nm film thickness. A correlated composite nanostructure evolution is responsible for nitrogen induced magnetization and, suggests that film properties can tuned by controlling nitrogen content, in CoN/ZrN composite matrix.