170 research outputs found
Anizotropni svemiri Bianchijeve III vrste s oblakom struna u Lyrinoj geometriji
Bianchi type-III string cosmological models are investigated in the presence of string fluid as a source of matter in the framework of Lyra’s geometry. It is observed that the models start with singular state and evolve continuously as t → ∞. It is found that, in all cases, the displacement vector β(t) is a decreasing function of time analogous to the behaviour of the cosmological constant Λ. The physical and geometrical aspects of the models are also discussed.Istražujemo Bianchijeve kozmološke modele III vrste u prisustvu tekućine struna kao izvora tvari u okviru Lyrine geometrije. Nalazimo da prema modelima svemir počinje sa singularnim stanjem i razvija se postepeno kako t → ∞. U svim slučajevima smo našli da je vektor posmika β(t) opadajuća funkcija vremena, poput svojstva kozmološke stalnice Λ. Raspravljamo fizičke i geometrijske značajke modela
Spark Plasma Sintering of Aluminum Matrix Composites
Aluminum matrix composites make a distinct category of advanced engineering materials having superior properties over conventional aluminum alloys. Aluminum matrix composites exhibit high hardness, yield strength, and excellent wear and corrosion resistance. Due to these attractive properties, aluminum matrix composites materials have many structural applications in the automotive and the aerospace industries. In this thesis, efforts are made to process high strength aluminum matrix composites which can be useful in the applications of light weight and strong materials. Spark Plasma Sintering (SPS) is a relatively novel process where powder mixture is consolidated under the simultaneous influence of uniaxial pressure and pulsed direct current. In this work, SPS was used to process aluminum matrix composites having three different reinforcements: multi-wall carbon nanotubes (MWCNTs), silicon carbide (SiC), and iron-based metallic glass (MG). In Al-CNT composites, significant improvement in micro-hardness, nano-hardness, and compressive yield strength was observed. The Al-CNT composites further exhibited improved wear resistance and lower friction coefficient due to strengthening and self-lubricating effects of CNTs. In Al-SiC and Al-MG composites, microstructure, densification, and tribological behaviors were also studied. Reinforcing MG and SiC also resulted in increase in micro-hardness and wear resistance.Mechanical & Aerospace Engineerin
Macronutrient intake in dyslipidemia: a population-based study from Haryana, North India
Background: Dyslipidemia is a highly prevalent physiological condition and it is one of the major risk factors for cardiovascular diseases (CVDs) worldwide. Diet as a modifiable factor gaining more scientific attention in managing the problem of dyslipidemia among vegetarian populations in order to reduce the burden of CVDs.
Methods: The present study was conducted on a total of 497 adult participants of either sex recruited randomly from Palwal Haryana, North India. Data related to socio-demographic variables was collected by using pretested and modified interview schedules. Dietary data was collected by using validated food frequency questionnaire (FFQ), and entered and analyzed by using Dietcal software. Lipid profile was done on 12 hours overnight fasting blood samples by using commercial kits Randox, USA. All the statistical tests were performed by using IMB’s SPSS software version 22.
Results: Adjusted odds ratio revealed that total fat intake was positively associated with TG and VLDL while carbohydrate intake was found to be positively associated with TG, low-HDL, LDL, and VLDL. >3 times intake of RDAs for total fats and carbohydrates posed 2.4 and 2-folds increased risk for high TG and VLDL.
Conclusions: Present study suggested a positive association between the intake levels of macronutrients and elevated lipids. Nutritional education and promoting diet diversity among vegetarian populations may reduce the burden of dyslipidemia
Study of prevalence of osteoporosis in males of above 40 years age group attending SMS Hospital, Jaipur
Background: Whenever osteoporosis is discussed, the focus is on women; men are far less likely to receive a diagnosis of osteoporosis or osteoporotic fracture because of considerable gaps in knowledge on male osteoporosis. The aim and objectives were to study the prevalence of osteoporosis in males of above 40 year age group attending SMS Hospital Jaipur & to explore the influence of various modifiable and non-modifiable risk factors on BMD.Methods: Study Location: SMS Medical College and Hospital, Jaipur. Study design: Hospital based cross sectional study. Study period: April 2015 to December 2016. Sample Size: 200. Work up: After taking ethical clearance and informed verbal consent, demographic and clinical details were noted along with S- calcium, Vitamin D and bone mineral density assessment. Osteoporosis was defined as T score ≤−2.5 bone mass −1 to −2.5 and normal as >−1. Data thus collected was analysed with help of SPSS 22.0 through frequency, percentages, Mean, SD and ANOVA.Results: Prevalence of osteopenia and osteoporosis in the study population was 28.5% and 11.5%. Age wise maximum prevalence was in the age group 71-80 years (31.81%). Prevalence of osteoporosis was more among Muslim community 20.83%, more in low socio economic group (BPL). T score of study population was -0.3705±1.41. The mean BMI, S-Calcium, Vitamin D levels and T score values among osteopenic and osteoporotic patients were statistically highly significant when compared to patients without osteo-penic/porotic changes (p<0.05).Conclusions: Osteoporosis is a silent killer and prevention is better than cure as prevention requires simple steps such as good dietary habits, active life style, good control of systemic disorders, reduced intake of tobacco and alcohol
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