Impact of Solid Rocket Propellant Grain Manufacturing Limitations on Launch Vehicle Capability

It is examined if any limitations in existing solid rocket propellant grain manufacturing methods adversely affected the payload capability of recent space launch vehicles. It is seen if the transition from heavy, segmented metal rocket motor casings to lightweight monolith composite casings is possible without loss of ability to design and realize high-performance grain configurations using simple and safe methods. Considering payload fraction as the comparative performance metric, recently flown solid rocket-propelled, small-lift launch vehicles were surveyed and ranked. Solid rocket boosters of underperforming launch vehicles were investigated for manufacturing factors influencing payload fraction by comparing them to boosters of better-performing launch vehicles in their weight class. Relationships between payload fraction and the solid boosters’ mass fractions, casing construction, shape of thrust profile, propellant grain configuration and method employed to manufacture the grain were analysed. It is shown that those launch vehicles that did not possess or use the technology necessary to manufacture high-performance grain configurations like undercut finocyl in monolith composite casings ended up having boosters delivering poor thrust profiles with high inert mass ultimately leading to low payload fractions

Magnetic fields at the periphery of UCHII regions from carbon recombination line observations

Several indirect evidences indicate a magnetic origin for the non-thermal width of spectral lines observed toward molecular clouds. In this letter, I suggest that the origin of the non-thermal width of carbon recombination lines (CRLs) observed from photo-dissociation regions (PDRs) near ultra-compact \HII\ regions is magnetic and that the magnitude of the line width is an estimate of the \alfven speed. The magnetic field strengths estimated based on this suggestion compare well with those measured toward molecular clouds with densities similar to PDR densities. I conclude that multi-frequency CRL observations have the potential to form a new tool to determine the field strength near star forming regions.Comment: To appear in ApJ Letter

SIGGMA: A Survey of Ionized Gas in the Galaxy, Made with the Arecibo Telescope

A Survey of Ionized Gas in the Galaxy, made with the Arecibo telescope (SIGGMA) uses the Arecibo L-band Feed Array (ALFA) to fully sample the Galactic plane (30 < l < 75 and -2 < b < 2; 175 < l < 207 and -2 < b < 1) observable with the telescope in radio recombination lines (RRLs). Processed data sets are being produced in the form of data cubes of 2 degree (along l) x 4 degree (along b) x 151 (number of channels), archived and made public. The 151 channels cover a velocity range of 600 km/s and the velocity resolution of the survey changes from 4.2 km/s to 5.1 km/s from the lowest frequency channel to the highest frequency channel, respectively.RRL maps with 3.4 arcmin resolution and line flux density sensitivity of 0.5 mJy will enable us to identify new HII regions, measure their electron temperatures, study the physics of photodissociation regions (PDRs) with carbon RRLs, and investigate the origin of the extended low density medium (ELDM). Twelve Hn{\alpha} lines fall within the 300 MHz bandpass of ALFA; they are resampled to a common velocity resolution to improve the signal-to-noise ratio (SN) by a factor of 3 or more and preserve the line width. SIGGMA will produce the most sensitive fully sampled RRL survey to date. Here we discuss the observing and data reduction techniques in detail. A test observation toward the HII region complex S255/S257 has detected Hn{\alpha} and Cn{\alpha} lines with SN>10

Engine Operated Screwjack

Automobiles prove to be the heart of locomotion. Even after decades of this industry appearance, one issue which was never solved is the avoidance of flat tyres. A long drive might be a soothing one to the heart but a flat tyre on such a drive collapses everything. Even a flat tyre on the way to the office may cause the day sick. There is no way out but to call a mechanic or in case of barren roads, change the tyre ourselves. Present day methods for changing the tyre requires a lot of mechanical power which may prove to be difficult for the weak and old people. To overcome this problem, an automatic engine operated screw jack is designed which outweighs the pneumatic and electrical automatic system in various aspects like reliability, maintenance, cost etc. This device uses only the engine power to lift the car in any terrain and altitude. An engine was selected for this purpose to work on and its characteristics were studied. Based on the result it proves that the device will be a success upon installation on any type of vehicle. Even heavy duty vehicles like trucks, lorry, and buses can be lifted at a very minimal cost. The device will be of low maintenance and the initial cost is also low when regarding its use. It is a onetime installation and so no recurrent cost needed at the time of puncture

Socio-economic status of fisherwomen community in coastal Vizianagaram district of Andhra Pradesh, India

The socio-economics of six fisherwomen co-operative societies in coastal Vizianagaram district of Andhra Pradesh were studied through field surveys by interviewing a total of 185 respondents. Respondents were mostly middle aged (31 – 56 years; 61.6%) living in nuclear families (64.9%). Majority of the fisherwomen were found illiterate (88.1%). A greater proportion (84.9%) of fisherwomen involved in fish marketing as a primary occupation followed by salting and curing (9.73%) and pickling of fishes (5.4%). More than half (56.2%) of the respondents earned &gt; Rs. 25,000 (USD$ 1 = Rs. 75) every month. The study revealed that the socio-economic condition of the fisherwomen in the study area is poor, with a high percentage of the illiteracy. Necessary steps should be taken by the Governments organizations, NGOs and respective stakeholders to improve the literacy level as well as livelihood status

Defect Detection in Weld Joints by Infrared Thermography

The objective of this present paper is to evaluate the effectiveness of infrared thermography (IRT) as a non-contact, fast and reliable non-destructive evaluation procedure for detection and quantification of defects in weld joints. In the present work, a friction stir welded (FSW) joint of two aluminum plates and three 316 LN stain-less steel (SS) weld-joints with lack of penetration (LOP), lack of fusion (LOF) and tungsten inclusion (TI) defects respectively, were inspected using IRT and digital radio-graphy (DRG). Using active thermography methods, a sub-surface tunnel defect along the weld line was successfully detected in the FSW joint and its length and width were estimated by suitable pixel calibration. Using lock-in thermography, optimum frequencies were determined for each of the specimens and defect-depths were estimated. Tempe-rature fall of the defect region and defect-free region were monitored as a function of time and it was found that the rate of temperature fall in the former case is slower than that in the latter one. Results from both the tech-niques, i.e., IRT and DRG were found to be in good agree-ment with each other in all the cases. Advantage of IRT is that it provides depth information also

Ценовая стратегия устойчивого развития предприятий зернопродуктового подкомплекса

Цель. Обосновать ценовую стратегию овладения устойчивым положением предприятий зернопродуктовогоподкомплекса на рынке зерна, муки, круп и хлебобулочных изделий

A Novel Approach to High-temperature In-situ Ultrasonic NDE Using Magnetostriction

Online ultrasonic NDE at high-temperature is of much interest to the power, process and automotive industries in view of possible savings in down-time. This paper describes a novel approach to develop ultrasonic transducers capable of high-temperature in-situ operation using the principle of magnetostriction. Preliminary design from previous research by the authors is extended for operation at 1 MHz, and elevated temperatures by using MetGlas s the magnetostrictive core. Ultrasonic signals in pulse-echo mode are experimentally obtained from the ultrasonic transducer thus developed, in simulated high temperature environment of 350 °C for 10 hours. Advantages and challenges for practical deployment of this approach are discussed

3D DDD modelling of dislocation-precipitate interaction in a nickel-based single crystal superalloy under cyclic deformation

Strain-controlled cyclic deformation of a nickel-based single crystal superalloy has been modelled by using three-dimensional (3D) discrete dislocation dynamics (DDD) for both [001] and [111] orientations. The work focused on the interaction between dislocations and precipitates during cyclic plastic deformation at elevated temperature, which has not been well studied yet. A representative volume element (RVE) with cubic γ’-precipitates was chosen to represent the material, with enforced periodical boundary conditions. In particular, cutting of superdislocations into precipitates was simulated by a back-force method. The global cyclic stress-strain responses were captured well by the DDD model when compared to experimental data, particularly the effects of crystallographic orientation. Dislocation evolution showed that considerably high density of dislocations was produced for [111] orientation when compared to [001] orientation. Cutting of dislocations into the precipitates had a significant effect on the plastic deformation, leading to material softening. Contour plots of in-plane shear strain proved the development of heterogeneous strain field, resulting in the formation of shear-band embryos