The X-ray Properties of Low-Frequency Quasi-Periodic Oscillations from GRS 1915+105 up to 120 keV

We present a study of the properties of strong 0.8-3.0 Hz quasi-periodic oscillations (QPOs) that occurred during 1997 RXTE observations of the microquasar GRS 1915+105 in the low-hard state. The high count rates allow us to track individual QPO peaks, and we exploit this to develop a QPO folding technique. In contrast to previous QPO studies with RXTE, we emphasize the high energy QPO properties and report the detection of a QPO in the 60-124 keV energy band. Our technique allows us, for the first time, to measure the phase of the QPO harmonics relative to the fundamental. Variation in this phase difference leads to changes in the shape of the QPO profile with energy and over time. The strength of the QPO fundamental increases up to 19 keV, but the data do not suggest that the strength continues to increase above this energy. In some cases, the QPO amplitudes in the 30-60 keV and 60-124 keV energy bands are significantly less than in the 13-19 keV and 19-29 keV energy bands. We also use our technique to measure the phase lag of the QPO fundamental and harmonics. In the case where negative phase lags are detected for the fundamental, positive phase lags are detected for the first harmonic.Comment: Submitted to ApJ, Refereed, 9 page

Nutritional evaluation of varying protein: energy ratios in feeds for Indian white shrimp Penaeus (Fenneropenaeus) indicus

Six experiments of six weeks duration were conducted in controlled conditions in the Indian white shrimp Fenneropenaeus indicus early juveniles (~0.040 mg initial weight). A common ingredient mixture (CIM) consisting of albumin (chicken egg), fish meal, shrimp meal, clam meal and deoiled ground nut oil cake was formulated and incorporated in all feeds at varying levels to obtain the requisite protein: energy combinations. Eight feeds tested in each experiment were formulated by incorporating CIM, cellulose (filler), tapioca flour (starch, binder), oil, mineral mixture, vitamin mixture and other additives viz., cholesterol and lecithin. The six protein levels fixed were 250 g kg-1 to 500 g kg-1 with 50 g kg-1 increments for each experiment. The gross energy (GE) levels in the eight dietary treatments for each level of protein varied from 290 kcal 100g-1 to 430 kcal 100g-1 and the digestible energy levels varied from198 – 300 kcal 100g-1. Growth, relative growth rate (RGR), absolute growth rate (AGR), food conversion efficiency (FCE), food conversion ratio (FCR), survival and initial and final body composition were monitored and analysed. One-way analysis of variance (ANOVA) followed by comparison of means was done to examine statistically significant differences between treatments and second degree polynomial regression of the from y = a + bx + cx2 was fitted with the data for RGR on P/E ratio (mg protein kcal-1), RGR on GE and RGR on DE to derive the optimum RGR, GE, DE and P/E. The results showed that growth of shrimp was highest with 450 g kg-1 protein and 363 kcal 100g- 1 GE, 276 kcal 100g-1 DE with a P/E of 124. Theoretical optima derived confirmed this observation with optimal values of 360 kcal 100g-1 GE, 275 kcal 100g-1 DE and a P/E ratio of 125. However, similar response in growth with feeds containing 350 - 450 g kg-1 protein indicating GE requirement of 362 – 371 kcal 100g-1 and DE requirement of 262 – 276 kcal100g-1 suggested a protein sufficiency of 350 g kg-1 with a P/E ratio of 98- 103 without major variations in the whole body composition

Laser Induced Selective Alignment of Water Spin Isomers

We consider laser alignment of ortho and para spin isomers of water molecules by using strong and short off-resonance laser pulses. A single pulse is found to create a distinct transient alignment and antialignment of the isomeric species. We suggest selective alignment of one isomeric species (leaving the other species randomly aligned) by a pair of two laser pulses.Comment: 6 pages, 4 figures, 3 table

Design, development and demonstration of a Shallow solar tunnel dryer for non-electrified areas

This paper presents the design, construction and performance evaluation of a shallow solar tunnel dryer for agro and industrial products. In the shallow solar tunnel dryer, there are three separate units viz.: an air heating unit, drying unit and air diversion unit. Total area of the solar tunnel dryer was 21 m². The heated air from a separate solar air heating zone is passed through a product bed, and at the same time, the drying tunnel bed absorbs solar energy directly through the transparent UV stabilized plastic sheet used as covering material. This dryer was not required any external sources of the power to operate the electrical fan. The system was designed to operate at a temperature of 50 to 60oC. The system was installed at the institute and initial testing was conducted. After that the system was also demonstrated at the actual potential user’s site. The results obtained during the test period revealed that the temperatures inside the tunnel drying zone and solar air heating zone were much higher than the ambient air temperature during most hours of the day-light. The temperature rise inside the drying tunnel was up to 67.4°C at peak hour’s period (noon). The drying rat e and thermal efficiency of the collector were 1.73 kg/h and 26.0% respectively. The high outlet temperature indicated the scope of loading the dryer further

Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption

The structure and properties of the diffuse interstellar medium (ISM) on small scales, sub-au to 1 pc, are poorly understood. We compare interstellar absorption-lines, observed towards a selection of O- and B-type stars at two or more epochs, to search for variations over time caused by the transverse motion of each star combined with changes in the structure in the foreground ISM. Two sets of data were used: 83 VLT- UVES spectra with approximately 6 yr between epochs and 21 McDonald observatory 2.7m telescope echelle spectra with 6 - 20 yr between epochs, over a range of scales from 0 - 360 au. The interstellar absorption-lines observed at the two epochs were subtracted and searched for any residuals due to changes in the foreground ISM. Of the 104 sightlines investigated with typically five or more components in Na I D, possible temporal variation was identified in five UVES spectra (six components), in Ca II, Ca I and/or Na I absorption-lines. The variations detected range from 7\% to a factor of 3.6 in column density. No variation was found in any other interstellar species. Most sightlines show no variation, with 3{\sigma} upper limits to changes of the order 0.1 - 0.3 dex in Ca II and Na I. These variations observed imply that fine-scale structure is present in the ISM, but at the resolution available in this study, is not very common at visible wavelengths. A determination of the electron densities and lower limits to the total number density of a sample of the sightlines implies that there is no striking difference between these parameters in sightlines with, and sightlines without, varying components.Comment: 19 pages, 11 figures, accepted for publication in MNRA

Carbon dioxide adsorption and interaction with formation fluids of Jordanian unconventional reservoirs

Shales are mostly unexploited energy resources. However, the extraction and production of their hydrocarbons require innovative methods. Applications involving carbon dioxide in shales could combine its potential use in oil recovery with its storage in view of its impact on global climate. The success of these approaches highly depends on various mechanisms taking place in the rock pores simultaneously. In this work, properties governing these mechanisms are presented at technically relevant conditions. The pendant and sessile drop methods are utilized to measure interfacial tension and wettability, respectively. The gravimetric method is used to quantify CO2 adsorption capacity of shale and gas adsorption kinetics is evaluated to determine diffusion coefficients. It is found that interfacial properties are strongly affected by the operating pressure. The oil-CO2 interfacial tension shows a decrease from approx. 21 mN/m at 0.1 MPa to around 3 mN/m at 20 MPa. A similar trend is observed in brine-CO2 systems. The diffusion coefficient is observed to slightly increase with pressure at supercritical conditions. Finally, the contact angle is found to be directly related to the gas adsorption at the rock surface: Up to 3.8 wt% of CO2 is adsorbed on the shale surface at 20 MPa and 60 °C where a maximum in contact angle is also found. To the best of the author’s knowledge, the affinity of calcite-rich surfaces toward CO2 adsorption is linked experimentally to the wetting behavior for the first time. The results are discussed in terms of CO2 storage scenarios occurring optimally at 20 MPa