14 research outputs found
Development of Smart Squeeze Film Dampers for Small Rotors
No full textAbstractSqueeze film dampers (SFD) are lubrication elements which provide viscous damping in rotating systems. Squeeze film dampers in rotating machinery provide structural isolation, reduce the amplitudes of rotor response to unbalance and also assist to suppress rotor dynamic instability. They have been long used to subdue instability and vibration issues that are difficult to solve using conventional bearings like journal or ball bearings. Numerous studies have been tried to produce mechanically tunable dampers which allow the damping to be changed during different mode of operation. Magneto-rheological (MR) fluids are one of the strong contenders for tunable dampers. They provide the possibility to control the dynamic characteristics of conventional fluid dampers. Magneto-rheological fluids are viscous fluids suspended with micron sized ferromagnetic particles which on application of magnetic field undergo changes in their physical and mechanical properties like viscosity, stiffness, etc. This characteristic can be used to build squeeze film damper whose damping properties will change based on the input force. In present work a typical SFD is designed and development using MR fluid and tested for different amount of damping. It is observed that the damping provided by MR fluid increases with increase in magnetic field and the amplitude of vibration reduces by 70% at critical speeds
Mechanical, electrical, and thermal analysis of sisal fibril/kenaf fiber hybrid polyester composites
No full textHVOF sprayed Ni 3 Ti and Ni 3 Ti+(Cr 3 C 2 +20NiCr) coatings: Microstructure, microhardness and oxidation behaviour
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No full textNot AvailablePresent study was undertaken to study the inheritance pattern of yield and mineral nutrients (Iron, Phosphorus, Potassium and Zinc) using five parameter generation mean analysis (P1, P2, F1, F2 and F3) in two peanut crosses (Girnar-3 × FDRS-10 and TG-37A × FDRS-10). Scaling and joint scaling tests were significant for most characters studied indicating that additive-dominance model alone is not enough to explain the inheritance of characters studied. Both additive and dominance variance played important role for most of the traits. Traits PY, HY, HKW, SHP and RDW are governed by additive gene whereas Kshoot, Kroot, Feshoot, Feroot, Pshoot and Proot were governed by both additive and non-additive gene effects. Positive estimates of ‘i’ for Zn, K and P in cross-1 (Girnar-3 × FDRS-10) indicates that parents employed were phenotypically diverse. Therefore cross-1 holds better chance for identifying genotypes with high mineral concentrations without compromising yield levels. Hence, pedigree method of breeding could be followed for improving yield and selection could be followed in later generation when population is stable to select genotypes with high mineral concentrations.Not Availabl
Studies on in vitro manipulation of male and female reproductive systems of flowering plants
No full textThe overall aim of this research project is to investigate the possibility of using pollen as a vector for transporting extracellular substances to the site of gamete fusion in the embryo sac. Manipulation of plant male and female gametophytes included studies on pollen culture in vitro, pollen viability and developmental state, loading of fluorescent probes by plasmolysis/endocytosis and via vascular system, clearance of embryo sacs, ovule culture and the in vitro fertilisation and production of genetically uniform lines.Pollen from Impatiens glanduiifera cultured under a range of nutrients (sucrose, H(_3)B(_O4), Ca. K and Mg), temperature and humidity conditions revealed that 5% sucrose, lOOppm H(_3)BO(_4) with 100 ppm potassium nitrate, gave longer pollen tubes (463.20 pm after 1 h). Pollen tubes were longer at room temperature; however, they also grew under temperatures down to 4 C. The effect of humidity levels was also significant, and pollen tube length increased with the increase of relative humidity (RH) over the range 0.0 to 92.0%. Plasmolysis followed by deplasmolysis of pollen gave a non-significant effect on tube growth compared to the control treatment.Assessment of pollen viability using fluorescein diacetate (FDA) and Calcofluor White M2R (CFW) highlighted some drawbacks on the most widely used technique for assessing pollen viability, the fluorochromatic reaction. Pollen developmental state in I. glandulifera was assessed using the Feulgen staining technique. The use of DNA-specific 4,6-diamidino-2- phenyl indole (DAPl) has clearly shown the vegetative and generative nuclei. Pollen tubes were monitored using aniline blue.When pollen were plasmolysed and deplasmolysed in the presence of 5 mg ml (^-1) Lucifer Yellow CH (LY-CH), the fluorescent probe was taken into pollen and the most likely mechanism by which it was taken up was through plasmolysis/endocytosis. The loading up into pollen of FDA by enzymic cleavage and fluorescein by endocytosis is also discussed. Fluorescein, LY-CH and Calcofluor White M2R were loaded via the vascular system of Nicotiana tabacum, I. glandulifera and Brassica napus. Using fluorescence microscopy, the path of these probes was followed from the pedicel cells up to the ovules.The demonstration of loading of fluorescent probes into embryo sacs, whether via germinating pollen or via the vascular system, required manipulation of ovaries and clearance of embryo sacs. The fixing and clearing technique revealed, to some extent, embryo elements in I. glandulifera and N. tabacum. The enzymic maceration technique, however, resulted in the isolation of I. glandulifera embryo sacs. The embedding in London Resin White (LR White) technique was used to reveal additional information.In vitro stigmatal pollination of I. glandulifera ovaries resulted in pollen tubes penetrating into the ovules. When this was conducted in the presence of Lucifer Yellow CH, B. napus pollen tubes were seen carrying the probe and penetrating into the ovule. Fully grown N. tabacum plants were obtained from ovaries cultured and pollinated in vitro.Micro-propagation of I. glandulifera, N. tabacum and B. napus in Murishige and Skoog, and Nitsch and Nitsch -based media resulted in plantlets from B. napus and Nicotiana tabacum. Acclimatisation of the latter, under humid conditions, resulted in fully grown plants
Forecasting the effects of smoking prevalence scenarios on years of life lost and life expectancy from 2022 to 2050: a systematic analysis for the Global Burden of Disease Study 2021
No full textBackgroundSmoking is the leading behavioural risk factor for mortality globally, accounting for more than 175 million deaths and nearly 4·30 billion years of life lost (YLLs) from 1990 to 2021. The pace of decline in smoking prevalence has slowed in recent years for many countries, and although strategies have recently been proposed to achieve tobacco-free generations, none have been implemented to date. Assessing what could happen if current trends in smoking prevalence persist, and what could happen if additional smoking prevalence reductions occur, is important for communicating the effect of potential smoking policies. MethodsIn this analysis, we use the Institute for Health Metrics and Evaluation's Future Health Scenarios platform to forecast the effects of three smoking prevalence scenarios on all-cause and cause-specific YLLs and life expectancy at birth until 2050. YLLs were computed for each scenario using the Global Burden of Disease Study 2021 reference life table and forecasts of cause-specific mortality under each scenario. The reference scenario forecasts what could occur if past smoking prevalence and other risk factor trends continue, the Tobacco Smoking Elimination as of 2023 (Elimination-2023) scenario quantifies the maximum potential future health benefits from assuming zero percent smoking prevalence from 2023 onwards, whereas the Tobacco Smoking Elimination by 2050 (Elimination-2050) scenario provides estimates for countries considering policies to steadily reduce smoking prevalence to 5%. Together, these scenarios underscore the magnitude of health benefits that could be reached by 2050 if countries take decisive action to eliminate smoking. The 95% uncertainty interval (UI) of estimates is based on the 2·5th and 97·5th percentile of draws that were carried through the multistage computational framework. FindingsGlobal age-standardised smoking prevalence was estimated to be 28·5% (95% UI 27·9–29·1) among males and 5·96% (5·76–6·21) among females in 2022. In the reference scenario, smoking prevalence declined by 25·9% (25·2–26·6) among males, and 30·0% (26·1–32·1) among females from 2022 to 2050. Under this scenario, we forecast a cumulative 29·3 billion (95% UI 26·8–32·4) overall YLLs among males and 22·2 billion (20·1–24·6) YLLs among females over this period. Life expectancy at birth under this scenario would increase from 73·6 years (95% UI 72·8–74·4) in 2022 to 78·3 years (75·9–80·3) in 2050. Under our Elimination-2023 scenario, we forecast 2·04 billion (95% UI 1·90–2·21) fewer cumulative YLLs by 2050 compared with the reference scenario, and life expectancy at birth would increase to 77·6 years (95% UI 75·1–79·6) among males and 81·0 years (78·5–83·1) among females. Under our Elimination-2050 scenario, we forecast 735 million (675–808) and 141 million (131–154) cumulative YLLs would be avoided among males and females, respectively. Life expectancy in 2050 would increase to 77·1 years (95% UI 74·6–79·0) among males and 80·8 years (78·3–82·9) among females. InterpretationExisting tobacco policies must be maintained if smoking prevalence is to continue to decline as forecast by the reference scenario. In addition, substantial smoking-attributable burden can be avoided by accelerating the pace of smoking elimination. Implementation of new tobacco control policies are crucial in avoiding additional smoking-attributable burden in the coming decades and to ensure that the gains won over the past three decades are not lost. FundingBloomberg Philanthropies and the Bill & Melinda Gates Foundation.Bloomberg Philanthropies and the Bill & Melinda Gates Foundation
Is inhibition of the renin-angiotensin system a new treatment option for Alzheimer's disease?
No full textFindings from longitudinal and cross-sectional studies suggest an association between high blood pressure and dementia, and in turn the use of antihypertensives has been suggested to reduce incidence of dementia. Alzheimer's disease, the most common cause of dementia, is characterised in part by the deposition of amyloid beta protein (Abeta) in the brain. Reduction of Abeta load is now a major therapeutic strategy. In recent years the renin-angiotensin system, already of recognised importance in the pathogenesis of hypertension, has become a source of interest in the pathogenesis of Alzheimer's disease. This review explores molecular, genetic, and clinical studies that might help explain the relation between the renin-angiotensin system, hypertension, and Alzheimer's disease and whether treatment with angiotensin converting enzyme (ACE) inhibitors and similar treatment strategies have a part to play in the management of the disease
Transverse momentum spectra of charged particles in proton–proton collisions at √s=900 GeV with ALICE at the LHC
No full textThe inclusive charged particle transverse momentum distribution is measured in proton–proton collisions at s=900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|η|<0.8) over the transverse momentum range 0.15<pT<10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |η|<0.8 is 〈pT〉INEL=0.483±0.001 (stat.)±0.007 (syst.) GeV/c and 〈pT〉NSD=0.489±0.001 (stat.)±0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger 〈pT〉 than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET
Suppression of charged particle production at large transverse momentum in central Pb–Pb collisions at √sNN=2.76 TeV
No full textInclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at √sNN=2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0–5% and 70–80% of the hadronic Pb–Pb cross section. The measured charged particle spectra in |η|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6–7 GeV/c and increases significantly at larger pT. The measured suppression of high-pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb–Pb collisions at the LHC
