Letters on the Baluch-Afghan Boundary Commission of 1896 (1909)

Written to the English (Calcutta) and Times of India (Bombay) by their special correspondent with the Mission

\u3ci\u3eLetters on the Baluch-Afghan Boundary Commission of 1896 (1909)\u3c/i\u3e

Written to the English (Calcutta) and Times of India (Bombay) by their special correspondent with the Mission

Base pressure behaviour in a suddenly expanded duct at supersonic mach number regimes using Taguchi design of experiments

Experimental investigations are carried out to study the control of base pressure without and with the use of micro-jets through suddenly expanded axi-symmetric passage in the supersonic regime. Four micro jets having an orifice diameter of 1mm were located at 90◦ intervals. In the base area, active controls jets have been placed on a pitch of a circle diameter that is 1.3 times the exit diameter of the nozzle. The jets were dispensed abruptly into the axi-symmetric tube maintained at a cross-sectional area of 4.84 times the exit nozzle area. The variation of base pressure as a function of flow control parameters namely Mach number, nozzle pressure ratio (NPR) and length to diameter) ratio (L/D) are evaluated experimentally. This study also assesses the impact of flow control variables on base pressure for two cases viz. with control and without control respectively. An L9 orthogonal array of Taguchi and the analysis of variance were employed to investigate the percentage of contribution of these parameters and their interactions affecting the base pressure. The correlations between the various factors affecting the base pressure were obtained by using multiple linear regression equations. Confirmation tests were conducted in order to test the developed linear regression equations for their practical significance. Both the regression models were found to be significant and reliable with a percentage deviation lying in the range of −6.12% to 10.26% for base pressure without control and −13.92% to 6.58% for base pressure with control. Analysis of variance was also performed in order to determine the statistical significance of each parameter on the total variability of base pressure. The study concluded that Mach number is the most influential parameter affecting base pressure followed by NPR and L/D

Study of effect of flow parameters on base pressure in a suddenly expanded duct at supersonic mach number regimes using CFD and design of experiments

Effectiveness of active control of micro jets has been examined by conducting experiments through an abruptly expanded axi-symmetric duct in a view to control base pressure. For this purpose, 1mm orifice diameter micro jets have been deployed at an interval of 900 along the exit diameter of the nozzle. The experiments have been conducted by considering three flow parameters at three levels. Mach number (M), length to diameter (L/D) ratio and area ratio (AR) are the three parameters used to conduct and analyze the flow experiments. Base pressure is considered to be the response variable. The experimentation has been carried out for two cases, i) without active control; ii) with active control. An L9 orthogonal array has been implemented to plan the experiments. It is observed that the control becomes effective for lower area ratios when compared to the higher ones. In addition to this, at high area ratios suction at the base decreases and hence base pressure continuous to diminish with increasing L/D until it reaches a value of L/D=6. The obtained experimental results are subjected to multiple linear regression analysis and Analysis of variance (ANOVA). The performances of the two linear regression models were tested for their prediction accuracy with the help of 15 random test cases. It is observed that, both linear regression models for base pressure without and with control are statistically adequate and capable of making accurate predictions. Furthermore, this work also concludes that, Mach number is the most significant factor affecting base pressure followed by area ratio and L/D ratio for both cases of experimentation. The obtained experimental results are further validated by CFD analysis and are found to be in good concurrence with each other

Comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings in relation to growth, ion contents and enzyme activities

The experiments were carried out to evaluate the comparative study for salt stress among seed, root stock and direct regenerated violet (Viola odorata L.) seedlings. Violet seedlings propagated through tissue culture (direct regeneration) had significantly higher salicylic acid (SA) concentrations from seed and rootstock propagated plants. Random amplified polymorphic DNA (RAPD) studies prior to the salt treatments revealed that genetic similarity at the molecular level among seed, root stock and direct regenerated violet seedlings was 50.9 to 70.5%. NaCl applications (50 mol m–3) reduced plant and root lengths, plant fresh and dry weights in plants obtained through seeds and rootstock as compared to direct regenerated seedlings. Direct regenerated violet showed better plant growth significantly both in saline and non-saline conditions. Seedlings raised through direct regeneration strongly inhibited accumulation of Na+, K+, Ca2+ and Cl− and organic solute accumulations as glycinebetaine (GB) and root total soluble carbohydrates (TSC) but stimulated N and relative water contents (RWC). Direct regenerated seedlings showed an enhanced catalase (CAT), ascorbate peroxidase (APX) and guaiacol dependent peroxidase (GDP) activities as compared to seed and root stock propagated plants. It was concluded that direct regenerated plants had better performance under salt stress in relation to growth and ion accumulations as compared to seed and root stock propagated violet seedlings. This might be due to higher SA concentrations in direct regenerated seedlings which resulted from somaclonal variations or growth media applied during tissue culture technique

7-Chloro-2-[1-(4-methoxy­phen­yl)pyrazol-4-yl]-3,3-dimethyl-3H-indole

In the title compound, C20H18ClN3O, the dihedral angle between the pyrazole and the 3H-indole components is only 13.28 (6)°, indicating that there is conjugation between the two heterocyclic subunits. The N-methoxy­phenyl unit makes a dihedral angle of 25.10 (7)° with the pyrazole ring

What molecular mechanism is adapted by plants during salt stress tolerance?

Salt stress harmfully shocks agricultural yield throughout the world affecting production whether it is for subsistence or economic outcomes. The plant response to salinity consists of numerous processes that must function in coordination to alleviate both cellular hyper-osmolarity and ion disequilibrium. Salt tolerance and yield stability are complex genetic traits that are difficult to establish in crops since salt stress may occur as a catastrophic episode, be imposed continuously or intermittently and become gradually more severe at any stage during development. Molecular biology research has provided new insight into the plant response to salinity and identified genetic determinants that effect salt tolerance. Recent confirmation that many salt tolerance determinants are ubiquitous in plants has led to the use of genetic models, like Arabidopsis thaliana, to further dissect the plant salt stress response. Since manyof the most fundamental salt tolerance determinants are those that mediate cellular ion homeostasis, this review will focus primarily on the functional essentiality of ion homeostasis mechanisms in plantsalt tolerance. The transport systems that facilitate cellular capacity to utilize Na+ for osmotic adjustment and growth and the role of the Salt-Overly-Sensitive (SOS) signal transduction pathway in the regulation of ion homeostasis and salt tolerance will be particularly emphasized. The objective of the review is to know “What molecular mechanism is adopted by plants during salt stress tolerance?” A conclusion will be presented that integrates cellular based stress signaling and ion homeostasis mechanisms into a functional paradigm for whole plants and defines biotechnology strategies for enhancing salt tolerance of crops

CFD analysis of human powered submarine to minimize drag

This paper deals with finding the optimum fineness ratio, i.e. ratio of length to maximum diameter, of human-powered submarine of different shapes to reduce the drag force on the body using Computational Fluid Dynamics (CFD) analysis. These types of submarines are used in events like ISR and eISR. This paper focuses on finding the total drag force on submarine models with a constrained diameter and different fineness ratios. The analysis is done by using ANSYS Fluent. In this paper, only the fully submerged flow is considered on a hull without any appendages.The total drag on a body is caused in three different parts that are wave drag, skin friction drags and base drag.The analysis is done different shapes of submarines like Conic shape hull, Elliptical shape hull, Ogive shape hull and Parallel mid-body hull by flowing water at velocities of 3 m/s, 4m/s and 5 m/s. The fineness ratios at which the drag is minimum are found in all submarine shapes. The optimum value of fineness ratio, which gives minimum drag is obtained by the analysis is 6 for Conical shape hull, Elliptical shape hull and Ogive shape hull whereas for the submarine with Parallel mid-body hull shape the optimum fineness ratio is

Optimum spacing between grooved tubes: an experimental study

An experimental study on the optimum spacing between grooved tubes is reported in this paper. Two grooved tubes having a pitch of 10 mm and 15 mm and a plain tube were considered for the heat transfer analysis. The spacing between two tubes with the same pitch was varied from 10 mm to 35 mm with a step size of 5 mm. The velocity of air flowing over the tube surfaces was changed from 0.4 m/s to 1 m/s using a blower fan. Based on Nusselt number (Nu) the optimum spacing between the tubes was decided. The optimum spacing between grooved tubes of pitch 10 mm and 15 mm was compared with that of plain tubes. From the experimental analysis, it was noticed that with an increase in air velocity (increase in Reynolds number) the tube surface temperature reduced irrespective of any tube considered. Nu increased with an increase in air velocity for all the tubes. The important conclusion drawn from the present study was that there exists a limiting spacing (optimum) between the tubes above which no change in Nu was observed. The spacing of 30 mm was found to be the optimum spacing between the tubes irrespective of its surface geometry modifications