29 research outputs found
Feasibility studies on utilization of low-pressure in hydro-pneumatic driveline
The aim of this paper is to present a feasibility study on the use of low pressure in  vehicleâs small applications. Hydro-pneumatic driveline is one of the hybrid sub-systems for hydraulic hybrid vehicle. Usually, the energy supplied by hydro-pneumatic accumulator/storage operates through maximum energy level to a minimum. This often reaches  to the point where the limit of minimal operations is higher than the pre-charge limit. The remaining power is claimed as not effective to move a vehicle, but the pressure still contains energy. Therefore, it is a waste of energy. The pressure energy can be used to power vehicleâs small applications such as fan, starting motor, compressor, hybrid electric battery charger, and others. Hence, a laboratory-scale experiment was extended away to see the hydro-pneumatic drive system behavior to operate at low-pressure level. Through the experiment, it was found that the system can work at low-pressure level. However, the power generated was 740 watt, 16.2 Nm theoretical torque and operated at 52 % efficiency at a pressure of 50 bar. This value is too small if compared to the force needed to move the vehicle. Still, it was dependable enough to power the small application in the vehicle sub-system. Through this research, it is hoped that the ineffective pressure of the hydraulic hybrid vehicle can be utilized so it can contribute to the increase of efficiency
When someone gets sick, we run to them, not from themâ: holding space for solidarity otherwise and the cxxxity in times of COVID-19
Global Challenges (FGGA
Five Dimensional Cosmological Models in General Relativity
A Five dimensional Kaluza-Klein space-time is considered in the presence of a
perfect fluid source with variable G and . An expanding universe is
found by using a relation between the metric potential and an equation of
state. The gravitational constant is found to decrease with time as whereas the variation for the cosmological constant follows as
, and
where is the equation of state parameter and is the scale factor.Comment: 13 pages, 4 figures, accepted in Int. J. Theor. Phy
Large-scale magnetic fields from inflation due to a -even Chern-Simons-like term with Kalb-Ramond and scalar fields
We investigate the generation of large-scale magnetic fields due to the
breaking of the conformal invariance in the electromagnetic field through the
-even dimension-six Chern-Simons-like effective interaction with a fermion
current by taking account of the dynamical Kalb-Ramond and scalar fields in
inflationary cosmology. It is explicitly demonstrated that the magnetic fields
on 1Mpc scale with the field strength of G at the present time
can be induced.Comment: 18 pages, 6 figures, version accepted for publication in Eur. Phys.
J.
Cosmological consequences of a Chaplygin gas dark energy
A combination of recent observational results has given rise to what is
currently known as the dark energy problem. Although several possible
candidates have been extensively discussed in the literature to date the nature
of this dark energy component is not well understood at present. In this paper
we investigate some cosmological implications of another dark energy candidate:
an exotic fluid known as the Chaplygin gas, which is characterized by an
equation of state , where is a positive constant. By assuming
a flat scenario driven by non-relativistic matter plus a Chaplygin gas dark
energy we study the influence of such a component on the statistical properties
of gravitational lenses. A comparison between the predicted age of the universe
and the latest age estimates of globular clusters is also included and the
results briefly discussed. In general, we find that the behavior of this class
of models may be interpreted as an intermediary case between the standard and
CDM scenarios.Comment: 7 pages, 5 figures, to appear in Phys. Rev.
Direct inference and control of genetic population structure from RNA sequencing data
RNAseq data can be used to infer genetic variants, yet its use for estimating genetic population structure remains underexplored. Here, we construct a freely available computational tool (RGStraP) to estimate RNAseq-based genetic principal components (RG-PCs) and assess whether RG-PCs can be used to control for population structure in gene expression analyses. Using whole blood samples from understudied Nepalese populations and the Geuvadis study, we show that RG-PCs had comparable results to paired array-based genotypes, with high genotype concordance and high correlations of genetic principal components, capturing subpopulations within the dataset. In differential gene expression analysis, we found that inclusion of RG-PCs as covariates reduced test statistic inflation. Our paper demonstrates that genetic population structure can be directly inferred and controlled for using RNAseq data, thus facilitating improved retrospective and future analyses of transcriptomic data
Horizontal Axis Wind Turbine Performance Analysis
The present work uses the method of Blade Element Momentum Theory as suggested by Hansen. The method applied to three blade models adopted from Rahgozar S. with the airfoil data used the data provided by Wood D. The wind turbine performance described in term of the thrust coefficient , torque coefficient and the power coefficient . These three coefficient can be deduced from the Momentum theory or from the Blade element Theory(BET). The present work found the performance coefficient derived from the Momentum theory tent to over estimate. It is suggested to used the BET formulation in presenting these three coefficients. In overall the Blade Element Momentum Theory follows the step by step as described by Hansen work well for these three blade models. However a little adjustment on the blade data is needed. To the case of two bladed horizontal axis wind turbine, HansenââŹâ˘s approach works well over if the blade radius is the calculation should start from r = 0.1  
Gravimetrical, theoretical, and surface morphological investigations of corrosion inhibition effect of 4-(benzoimidazole-2-yl) pyridine on mild steel in hydrochloric acid
The corrosion inhibition efficiency of the novel pyridine namely, 4-(Benzoimidazole-2-yl)pyridine has been studied for mild steel in a 1 M hydrochloric acid environment by utilizing gravimetrical techniques. The synthesized inhibitor exhibits a significant inhibitive efficiency of 93.8% at 0.005 M. The adsorption isotherm of the investigated inhibitor on mild steel surface obeys the Langmuir isotherm. Surface morphology investigated by utilizing scanning electron microscopy (SEM) demonstrates a smooth metal surface with the addition of 4-(Benzoimidazole-2-yl)pyridine in a hydrochloric acid environment. Quantum chemical calculations using density functional theory (DFT) have been used to investigate the molecular structure and behavior of 4-(Benzoimidazole-2-yl) pyridine as a corrosion inhibitor. Different parameters have been calculated using DFT, such as energies of highest occupied molecular orbital and lowest occupied molecular orbital (EHOMO and ELUMO), energy gap (âE), and dipole moment (Îź). These parameters were important to elucidate the behavior of the investigated molecule as a corrosion inhibitor in acidic solution and also suggest the mechanism of inhibition