37 research outputs found

    Non-Newtonian Effects on the Squeeze Film Characteristics between a Sphere and a Flat Plate: Rabinowitsch Model

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    The use of additives (polyisobutylene, ethylene-propylene, lithium hydroxy stearate, hydrophobic silica, etc.) changes lubricants’ rheology due to which they show pseudoplastic and dilatant nature, which can be modelled as cubic stress fluid model (Rabinowitsch fluid model). The present theoretical analysis investigates the effects of non-Newtonian pseudoplastic and dilatant lubricants on the squeezing characteristics of a sphere and a flat plate. The modified Reynolds equation has been derived and an asymptotic solution for film pressure is obtained. The results for the film pressure distribution, load carrying capacity, and squeezing time characteristics have been calculated for various values of pseudoplastic parameter and compared with the Newtonian results. These characteristics show a significant variation with the non-Newtonian pseudoplastic and dilatant behavior of the fluids

    Development and evaluation of ready to serve (RTS) beverage from bael (Aegle marmelose Correa.)

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    A research study was carried out to develop a RTS beverage by exploiting the nutritional and organoleptic properties of bael fruit pulp. Six treatment combinationsof bael RTS with 10, 15 and 20% of pulp concentration and 10 and 15°B of TSS were prepared based on the review of literature. The biochemical and organoleptic properties of the prepared RTS were evaluated during storage. The pH, ascorbic acid and antioxidant activity of the RTS decreased with the storage, while acidity and total sugars increased. Results of the sensory evaluation showed that there was a significant difference between treatments in terms of color, flavor, taste, body and overall acceptability. From the results of quality assessments, the formulated bael RTS beverage with 15% pulp and 15°B TSS was found to be superior and suitable for consumption up to 12 weeks without any significant changes in the quality characteristics

    On the steady performance of annular hydrostatic thrust bearing”, Rabinowitsch fluid model

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    The present theoretical analysis investigates the simultaneous effect of lubricant inertia and non-Newtonian pseudoplastic lubricant (lubricant blended with viscosity index improver and viscosity thickener)-Rabinowitsch fluid model on the performance of externally pressurized annular hydrostatic thrust bearings. A close form solution is obtained for pressure distribution. The effect of centrifugal inertia on the pressure distribution in the recess region is considered by taking non-constant recess pressure under a hydrodynamic condition. The load capacity and flow rate have been numerically calculated for various values of viscosity index improver together with the centrifugal inertia effects. In the limiting case in which there is an absence of pseudoplasticity, the results are compared with the pre-established Newtonian lubricants and are found to be in good agreement

    Development and evaluation of ready to serve (RTS) beverage from bael (Aegle marmelose Correa.)

    Get PDF
    A research study was carried out to develop a RTS beverage by exploiting the nutritional and organoleptic properties of bael fruit pulp. Six treatment combinationsof bael RTS with 10, 15 and 20% of pulp concentration and 10 and 15°B of TSS were prepared based on the review of literature. The biochemical and organoleptic properties of the prepared RTS were evaluated during storage. The pH, ascorbic acid and antioxidant activity of the RTS decreased with the storage, while acidity and total sugars increased. Results of the sensory evaluation showed that there was a significant difference between treatments in terms of color, flavor, taste, body and overall acceptability. From the results of quality assessments, the formulated bael RTS beverage with 15% pulp and 15°B TSS was found to be superior and suitable for consumption up to 12 weeks without any significant changes in the quality characteristics

    Quantifying tropical cyclone's effect on the biogeochemical processes using profiling float observations in the Bay of Bengal

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    Physical and biogeochemical observations from an autonomous profiling Argo float in the Bay of Bengal show significant changes in upper ocean structure during the passage of Tropical Cyclone (TC) Hudhud (7–14 October 2014). TC Hudhud mixed water from a depth of about 50 m into the surface layers through a combination of upwelling and turbulent mixing. Mixing was extended into the depth of nutricline, the oxycline and the subsurface‐chlorophyll‐maximum; thus had a strong impact on the biogeochemistry of the upper ocean. Before the storm, the near‐surface layer was nutrient depleted and was thus oligotrophic with the chlorophyll‐a concentration of less than 0.15 mg m‐3. Storm mixing initially increased the chlorophyll by 1.4 mg m‐3, increased the surface nitrate concentration to about 6.6 μM kg‐1, and decreased the sub‐surface dissolved oxygen (30–35 m) to 31 % of saturation (140 μM). These conditions were favorable for phytoplankton growth resulting in an estimated increase in primary productivity averaging 1.5 g C m‐2 day‐1 over 15 days. During this bloom, chlorophyll‐a increased by 3.6 mg m‐3, and dissolved oxygen increased from 111 % to 123 % of saturation. Similar observations during TC Vardah (6–12 December 2016) showed much less mixing. Our analysis suggests that relatively small (high) translation speed and presence of cold (warm) core eddy leads to strong (weak) oceanic response during TC Hudhud (TC Vardah). Thus, although cyclones can cause strong biogeochemical responses in the Bay of Bengal, the strength of response depends on the properties of the storm and the prevailing upper ocean structure such as presence of mesoscale eddies

    Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array

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    Low-frequency, wide field-of-view (FOV) radio telescopes such as the Murchison Widefield Array (MWA) enable the ionosphere to be sampled at high spatial completeness. We present the results of the first power spectrum analysis of ionospheric fluctuations in MWA data, where we examined the position offsets of radio sources appearing in two data sets. The refractive shifts in the positions of celestial sources are proportional to spatial gradients in the electron column density transverse to the line of sight. These can be used to probe plasma structures and waves in the ionosphere. The regional (10–100 km) scales probed by the MWA, determined by the size of its FOV and the spatial density of radio sources (typically thousands in a single FOV), complement the global (100–1000 km) scales of GPS studies and local (0.01–1 km) scales of radar scattering measurements. Our data exhibit a range of complex structures and waves. Some fluctuations have the characteristics of traveling ionospheric disturbances, while others take the form of narrow, slowly drifting bands aligned along the Earth's magnetic field

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Effect of surface roughness on steady performance of hydrostatic thrust bearings: Rabinowitsch fluids

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    The present theoretical study is concerned with the analysis of surface roughness effects on the steady-state performance of stepped circular hydrostatic thrust bearings lubricated with non-Newtonian fluids: Rabinowitsch fluid model. To take the effects of surface roughness into account, Christensen’s theory for rough surfaces has been adopted. The expression for pressure gradient has been derived in stochastic form employing the energy integral approach. Results for stochastic film pressure and load-carrying capacity have been plotted and analyzed based on numerical results. Due to surface roughness, significant variations in the theoretical results of these properties have been observed

    Dynamic Performance Characteristics of a Curved Slider Bearing Operating with Ferrofluids

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    In the present theoretical investigation, the effect of ferrofluid on the dynamic characteristics of curved slider bearings is presented using Shliomis model which accounts for the rotation of magnetic particles, their magnetic moments, and the volume concentration in the fluid. The modified Reynolds equation for the dynamic state of the bearing is obtained. The results of dynamic stiffness and damping characteristics are presented. It is observed that the effect of rotation of magnetic particles improves the stiffness and damping capacities of the bearings
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