3,629 research outputs found
Experimental Investigation of Single Cylinder Diesel Engine using Tyre Pyrolysis Oil (TPO) Blends
Increasing industrialization and motorization led to a significant rise in demand of petroleum products. As these are the non-renewable resources, it will be troublesome to predict the availability of these resources in the future, resulting in uncertainty in its supply and price and is impacting growing economies like India importing 80% of the total demand of the petroleum products. Many attempts have been made by different researchers to find out alternate fuels for Internal Combustion engines. Many alternate fuels like Biodiesel, LPG (Liquefied Petroleum Gas), CNG (Compressed Natural Gas) and Alcohol are being used nowadays by different vehicles. In this context pyrolysis of scrap tires can be used effectively to produce oil, thereby solving the problem of waste tire disposal. In the present study, Experimental investigations were carried out to evaluate the performance and emission characteristics of a single cylinder diesel engine fueled by TPO10, TPO15, and TPO20 at a crank angle 260 before TDC (Top Dead Centre) and injection pressure of 190 bar keeping the blend quality by controlling the density and viscosity of tire pyrolysis oil within permissible limit of euro IV diesel requirement. The performance and emission results were analyzed and compared with that of diesel fuel operation. The results of investigations indicate that the brake thermal efficiency of the TPO - DF blend decreases by 2 to 3%. CO emissions are well within permissible limits. HC emissions are higher by about 20 to 40% at partial load whereas smoke opacity is lower by about 20 to 30% as compared to diesel fuel
Structural, Magnetic and Magneto-caloric studies of Ni50Mn30Sn20Shape Memory Alloy
We have synthesized a nominal composition of Ni50Mn30Sn20 alloy using arc
melting technique. Rietveld refinement confirms the austenite L21 structure in
Fm-3m space group. Electrical resistivity has been found to clearly exhibiting
two different phenomena viz. a magnetic transition from paramagnetic to
ferromagnetic and a structural transition from austenite to martensitic phase.
Thermo-magnetization measurements M(T) confirms ferromagnetic transition
temperature TC at 222 K and martensitic transition starting at 127 K(MS).
Magnetization measurement M(H) at 10 K confirms the ferromagnetic state.
Frequency dependence of ac susceptibility \c{hi}' at low temperature suggests
spin glass behavior in the system. The isothermal magnetic entropy change
values have been found to be 1.14 J/Kg.K, 2.69 J/Kg.K and 3.9 J/Kg.K, with
refrigeration capacities of 19.6 J/kg, 37.8 J/kg and 54.6 J/kg for the field
change of 1, 2 and 3 Tesla respectively at 227 K.Comment: 16 pages text + Figs. Ni50Mn30Sn20 alloy: reasonable refrigeration
capacity tunable to Room
Composition of Jupiter irregular satellites sheds light on their origin
Irregular satellites of Jupiter with their highly eccentric, inclined and
distant orbits suggest that their capture took place just before the giant
planet migration. We aim to improve our understanding of the surface
composition of irregular satellites of Jupiter to gain insight into a narrow
time window when our Solar System was forming. We observed three Jovian
irregular satellites, Himalia, Elara, and Carme, using a medium-resolution
0.8-5.5 micro m spectrograph on the National Aeronautics and Space
Administration (NASA) Infrared Telescope Facility (IRTF). Using a linear
spectral unmixing model we have constrained the major mineral phases on the
surface of these three bodies. Our results confirm that the surface of Himalia,
Elara, and Carme are dominated by opaque materials such as those seen in
carbonaceous chondrite meteorites. Our spectral modeling of NIR spectra of
Himalia and Elara confirm that their surface composition is the same and
magnetite is the dominant mineral. A comparison of the spectral shape of
Himalia with the two large main C-type asteroids, Themis (D 176 km) and Europa
(D 352 km), suggests surface composition similar to Europa. The NIR spectrum of
Carme exhibits blue slope up to 1.5 microm and is spectrally distinct from
those of Himalia and Elara. Our model suggests that it is compositionally
similar to amorphous carbon. Himalia and Elara are compositionally similar but
differ significantly from Carme. These results support the hypotheses that the
Jupiter irregular satellites are captured bodies that were subject to further
breakup events and clustered as families based on their similar physical and
surface compositions
Hopping Conduction in Uniaxially Stressed Si:B near the Insulator-Metal Transition
Using uniaxial stress to tune the critical density near that of the sample,
we have studied in detail the low-temperature conductivity of p-type Si:B in
the insulating phase very near the metal-insulator transition. For all values
of temperature and stress, the conductivity collapses onto a single universal
scaling curve. For large values of the argument, the scaling function is well
fit by the exponentially activated form associated with variable range hopping
when electron-electron interactions cause a soft Coulomb gap in the density of
states at the Fermi energy. The temperature dependence of the prefactor,
corresponding to the T-dependence of the critical curve, has been determined
reliably for this system, and is proportional to the square-root of T. We show
explicitly that nevlecting the prefactor leads to substantial errors in the
determination of the scaling parameters and the critical exponents derived from
them. The conductivity is not consistent with Mott variable-range hopping in
the critical region nor does it obey this form for any range of the parameters.
Instead, for smaller argument of the scaling function, the conductivity of Si:B
is well fit by an exponential form with exponent 0.31 related to the critical
exponents of the system at the metal- insulator transition.Comment: 13 pages, 6 figure
Water poverty in the northeastern hill region (India): potential alleviation through multiple-use water systems: cross-learnings from Nepal Hills
Water poverty index / Construction / Multiple use / Water storage / Farming systems / Villages / Social aspects / Drip irrigation / India / Nepal / Nagaland / Mon district / Lampong Sheanghah
PHYTOCHEMICAL SCREENING AND ANTI-TRICHOSPORON ACTIVITY OF PLUMBAGO ZEYLANICA LINN
Objective: To evaluate the anti-Trichosporon activity of a medicinal plant, Plumbago zeylanica Linn and to find out the phytochemicals responsible for this activity with the use of four solvent extracts; methanol, ethanol, acetone and chloroform.
Methods: To evaluate the antifungal activity, two methods were used. Agar well diffusion assay to determine the diameter of zone of inhibition (in mm) and MIC (in mg/ml) was determined through Tube dilution broth assay. Phytochemical screening for preliminary analysis of secondary metabolites was done through chemical methods.
Results: Trichosporon asahii was found to be most sensitive to methanol extract of P. zeylanica with inhibition zone of 35 mm and T. inkin with 30 mm zone of inhibition. MIC results also showed that the methanol extract was most effective in lowest concentration against T. asahii with MIC at 6.2 mg/ml and inhibited T. inkin at 25 mg/ml. Phytochemical screening of plant extracts revealed the presence of certain phyto-constituents like alkaloids, steroids, flavonoids, phenols, glycosides, tannins etc.
Conclusion: The present study proved the sensitivity of the yeast Trichosporon spp. to different extracts of P. zeylanica. T. asahii was found to be more sensitive towards the extracts. Methanol extract proved to be most effective compared to ethanol, acetone and chloroform as it gave the maximum zones and lowest MIC result. Phytochemical analysis proved the presence of certain phytochemicals which was responsible for their antifungal activity
Loss of correlation between HIV viral load and CD4+ T-cell counts in HIV/HTLV-1 co-infection in treatment naive Mozambican patients
Seven hundred and four HIV-1/2-positive, antiretroviral therapy (ART) naïve patients were screened for HTLV-1 infection. Antibodies to HTLV-1 were found in 32/704 (4.5%) of the patients. Each co-infected individual was matched with two HIV mono-infected patients according to World Health Organization clinical stage, age +/-5 years and gender. Key clinical and laboratory characteristics were compared between the two groups. Mono-infected and co-infected patients displayed similar clinical characteristics. However, co-infected patients had higher absolute CD4+ T-cell counts (P = 0.001), higher percentage CD4+ T-cell counts (P < 0.001) and higher CD4/CD8 ratios (P < 0.001). Although HIV plasma RNA viral loads were inversely correlated with CD4+ T-cell-counts in mono-infected patients (P < 0.0001), a correlation was not found in co-infected individuals (P = 0.11). Patients with untreated HIV and HTLV-1 co-infection show a dissociation between immunological and HIV virological markers. Current recommendations for initiating ART and chemoprophylaxis against opportunistic infections in resource-poor settings rely on more readily available CD4+ T-cell counts without viral load parameters. These guidelines are not appropriate for co-infected individuals in whom high CD4+ T-cell counts persist despite high HIV viral load states. Thus, for co-infected patients, even in resource-poor settings, HIV viral loads are likely to contribute information crucial for the appropriate timing of ART introduction
Gravitational and electromagnetic fields of a charged tachyon
An axially symmetric exact solution of the Einstein-Maxwell equations is
obtained and is interpreted to give the gravitational and electromagnetic
fields of a charged tachyon. Switching off the charge parameter yields the
solution for the uncharged tachyon which was earlier obtained by Vaidya. The
null surfaces for the charged tachyon are discussed.Comment: 8 pages, LaTex, To appear in Pramana- J. Physic
Theoretical study of pressure dependence of superconducting state parameters of some metals using pseudopotential approach
In the present theoretical study, we have calculated superconducting state parameters (SSPs) viz; electron-phonon coupling strength (λ), Coulomb pseudopotential (µ*), critical temperature (Tc), effective interaction strength (N0V) and isotopic effect parameter ( α) of some polyvalent metals (Pb, Ga, In, Sn and Tl) using well-established structured local pseudopotential due to Fiolhais et al. (1995). The pseudopotential with its individual set of parameters has been found to be good in predicting transition temperature Tc for all the metals. Looking to such success, we have extended the present model for the theoretical study of pressure dependence of transition temperature Tc using Debye- Gruneisen model. Our predicted critical volumes using different approaches are well agreed with each other and also with other reported findings. Thus, the present model is consistent and better than nonlocal norm conserving pseudopotentials because it is found to be transferable without any kind of adjustment of its parameters along with its simplicity and predictivity
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