ISRO Propulsion Complex

BACKGROUND: Chronic kidney disease (CKD) is common and ranks among the leading causes of mortality and morbidity. This analysis aimed to present global CKD estimates using the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 to inform evidence-based policies for CKD identification and treatment. METHODS: This analysis focused on adults aged 20 years and older over the period 1990 to 2023, from 204 countries and territories. Data sources used were published literature, vital registration systems, kidney failure treatment registries, and household surveys. Estimates of CKD burden, including deaths, incidence, prevalence, and disability-adjusted life-years (DALYs), were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool. A comparative risk assessment approach estimated the proportion of cardiovascular deaths attributable to impaired kidney function and estimated risk factors for CKD. FINDINGS: Globally, in 2023, 788 million (95% uncertainty interval 743-843) people aged 20 years and older were estimated to have CKD, up from 378 million (354-407) in 1990. The global age-standardised prevalence of CKD in adults was 14·2% (13·4-15·2), a relative rise of 3·5% (2·7-4·1) from 1990. The region with the highest age-standardised prevalence was north Africa and the Middle East (18·0%; 16·9-19·4). Most people had stage 1-3 CKD, with a combined prevalence of 13·9% (13·1-15·0). In 2023, CKD was the ninth leading cause of death globally, accounting for 1·48 million (1·30-1·65) deaths, and the 12th leading cause of DALYs, with an age-standardised DALY rate of 769·2 (691·8-857·4) per 100 000. Impaired kidney function as a risk factor accounted for 11·5% (8·4-14·5) of cardiovascular deaths. High fasting plasma glucose, body-mass index, and systolic blood pressure were all leading risk factors for CKD DALYs. INTERPRETATION: CKD is a major global health issue, with rising prevalence and increasing importance as a cause of death and as a risk factor for cardiovascular death. A better understating of aetiology, appropriate screening, and implementation programmes are needed to translate advances in CKD treatment into improved patient outcomes. FUNDING: Gates Foundation, Wellcome, US National Kidney Foundation, and US National Institute of Diabetes and Digestive and Kidney Diseases.

The results of a systematic experimental investigation on the methods of enhancing the regression rate in hydroxyl-terminated polybutadiene (HTPB) fuel used in an HTPB/gaseous oxygen hybrid motor are presented. The effects of the addition of ammonium perchlorate (AP) or aluminum in the fuel, the variation of oxidizer ‐fuel ratio, and the variation of characteristic dimensions of fuel grain are presented. For the extents of the parametric variations considered, while the addition of AP and/or Al and the reduction of grain port diameter enhance the regression rate, the effect due to the latter is the most signie cant one. Furthermore, the regression rate increases along theaxis, and it becomes essentially constant in the port region corresponding to a fuel-rich composition. The possible physical processes for all of these behaviors are discussed. The experimentally obtained exponents of the variables for regression rate (oxidizer mass e ux and port diameter ) are found to be signie cantly different from those of the conventional theory. The similarity between the fuel regression rate equation used in solid-fuel ramjet and that obtained in hybrid motor is discussed.

Medical Image Processing is a complex and challenging field nowadays. Processing of MRI images is one of the parts of this field. This paper proposes a strategy for efficient detection of a brain tumor in MRI brain images. The methodology consists of the following steps: preprocessing by using sharpening and median filters, enhancement of image is performed by histogram equalization, segmentation of the image is performed by thresholding. This approach is then followed by the further application of morphological operations. Finally the tumor region can be obtained by using the technique of image subtraction.

A variety of physical and chemical properties of bio-polymers like chitosan have been investigated although their inherent behavior, such as piezoelectricity, has not been investigated to date.

The detrimental laves formation in fusion zone during welding of Inconel 718 is controlled with compound current pulsing technique along with helium shielding gas. Also solid solution filler wire is used to minimize the niobium segregation. Welds were produced in 2mm thick sheets by GTA welding process and subjected to the characterization techniques. The results show, refined fusion zone microstructure, reduced amount of laves phase, minimum niobium segregation and softer fusion zone in the as welded condition.

Abstract Multi-objective facility layout problem (mFLP) generates a different layout by varying objectives weights. Since the selection of objective weights in mFLP is critical, stages of designing layout having multiple objectives, the objective weights therefore play an important role in the layout design of mFLP. In practice, it is selected randomly by the layout designer based on his/her past experience that restricts the layout designing process completely designer dependent and thus the layout varies from designer to designer. This paper aims to resolve the issues of selecting the objective weight for each objective. We propose four methods to determine objective weight which makes the design process of mFLP completely designer independent. Keywords: relative objective weightmulti-objective facility layout problemquadratic assignment problemheuristic Acknowledgements The authors would like to put on record their appreciation to anonymous learned referees for their valuable suggestions which have substantially enhanced the quality of the paper over the previous version.

Abstract Cryogenic systems have played a crucial role in almost all of the finest technological achievements of mankind. Cryogenic applications demand materials with a unique combination of properties, which drastically limits the choice of materials. In most other engineering applications, because of wide tailorability of their properties and excellent combination of strength and toughness, coupled with lower cost compared with nonferrous materials, steels have become the preferred/dominant structural material for cryogenic applications. The contradictory requirement of higher strength without compromising toughness at cryogenic temperatures posed considerable challenges and led to the development of large array of steels tailored for specific applications. This review is an attempt to survey the metallurgical aspects, material selection, mechanical property evaluation, and application of various standard and nonstandard steels for cryogenic applications. This review covers the influence of low temperatures on material properties, simulative mechanical tests for property evaluation, metallurgy of steels, and application examples surveying the published literature to date. The review also analyzes the origins of low-temperature toughness, various application requirements, and the work carried out at authors’ laboratories. The issues pertaining to mechanical tests at low temperatures and status of data generation in international scenario have been critically analyzed. Physical metallurgy aspects have been highlighted in the review, and microstructure-property-processing correlations for various steels have also been covered. One of the recent advances in steels for cryogenic applications, high-entropy alloys, which are proposed as alternatives for the conventional steels, have been reviewed, and mechanical property data have been critically analyzed. The potential of additive manufactured steels for low-temperature applications has been reviewed. Finally, this review article discusses challenges in processing–mechanical properties correlation for various grades of steels for cryogenic applications. It also provides useful information for researchers working on steels for cryogenic applications with a glimpse of recent advances made in this area.

In real decision making problems, many conflicting objectives have to be taken into account. With increasing awareness of this, multi-objective problems have become more and more popular. Similarly, the design of the multi-objective facility layout problem (MOFLP) has generally been recognised as an important issue in the modern manufacturing system. The MOFLP is formulated as a quadratic assignment problem (QAP) which is NP-hard and solving MOFLP is a tough problem. A new three-level AHP-based heuristic algorithm for resolving the MOFLP is presented here. It also presents a new normalisation procedure (H-1), and a new heuristic method (H-2) for generating objective weights. The proposed approach consists of three levels. The first level applies AHP to generate paired comparison matrices, the consistency of matrix, to convert inconsistent matrices into consistent ones and then generate a qualitative objective matrix; the second level applies normalisation procedure (H-1) to normalise matrices of qualitative and quantitative objectives and the third level computes the objective weight for qualitative and quantitative objectives. An illustrative example is shown to demonstrate an application of the proposed methodology for solving MOFLP.

The influence of variations of interface temperature in the range 50–300 K on the thermal contact conductance between aluminium and stainless steel joints was determined. Predictions were done by modeling the deformation at the interface for different values of surface finish and contact pressure over the range of interface temperatures. Both elastic and plastic deformation was considered. Experiments were carried out in a closed loop cryostat and the results were shown to compare well with the predictions. A reduction of the interface temperature resulted in a smaller value of thermal contact conductance. Interfacial pressure variation had much lower influence at the smaller value of temperatures. The role of surface roughness at the contact was also seen to be less significant at lower interface temperatures and the zone of hysteresis was smaller. A correlation was developed for estimating thermal contact conductance at joints over this temperature range. An explicit dependence of contact conductance on temperature was not seen to be necessary as long as the changes in the hardness and thermal conductivity of the material with temperature are incorporated in the correlation.

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

The shape and disintegration characteristics of swirled annular liquid sheets formed in coaxial injectors are investigated. The effects of ambient pressure and gas flows over the outer and inner surfaces of the liquid sheet are determined. Two general regimes of annular sheets, comprised of a tulip shape and a conical diverging shape, are shown to be formed depending on injector pressure drop, swirl, and orifice size. The transition from the tulip shape to the diverging conical shape occurs when the centrifugal forces at the injector orifice exit exceeds the surface tension forces by about two orders of magnitude. A conical sheet is not formed in annular orifice when the radial clearance of the orifice is of the same order of magnitude as the thickness of the liquid film. The tulip-shaped sheet is very sensitive to small changes in environmental and injection conditions, unlike the diverging conical liquid sheet.

Organic and inorganic entities have been hybridized using 3-aminopropyltriethoxysilane (APTES) linker for the synthesis of three novel organic–inorganic hybrid catalysts [Cu(<sc>ii</sc>), Co(<sc>ii</sc>) and Ni(<sc>ii</sc>)].

The effect of surface roughness, waviness and flatness deviations on thermal contact conductance is predicted. Threshold values of the surface parameters which do not adversely influence thermal contact conductance are determined. Flatness deviations less than ten times the average roughness and waviness less than about four times the average roughness do not significantly affect the contact conductance. A correlation is developed for contact conductance in terms of the surface parameters, the material properties and the contact pressure at the joint. Experiments are conducted in vacuum with rough, non-flat and wavy surfaces and the experimental results are demonstrated to agree well with the predictions.

Experiments are conducted to study the tulip-shaped and cone-shaped liquid sheets formed in swirl nozzles. Waves rapidly grow on the cone-shaped sheets and lead to its rupture unlike in the tulip-shaped sheets. The transition from the tulip-shaped to the cone-shaped sheet occurs when the liquid phase Weber number of the swirled annular sheet exceeds about 150. The turbulence level in the liquid sheet does not influence the Weber numher at which the transition of the shape of the sheet takes place. The frequencies and rate of growth of the waves on the liquid sheets increase with Weber number. The transition takes place when the growth rate of waves is significant. The predicted variations of frequencies and growth rates, obtained by linear perturbation of the axial momentum equation, reproduce the increasing trends with Weber number observed in the experiments; however, the values are higher than those measured. A linear bifurcation analysis brings out the role of the different parameters influencing the stability of the swirled liquid sheet. The annular sheet is seen to be inherently unstable

Experiments were carried out on a shallow open cavity (L/D = 5) at a supersonic Mach number (M = 1.8) to understand its transient starting characteristics, wave propagation (inside and outside the cavity) during one vortex shedding cycle, and acoustic emission. Starting characteristics and wave propagation were visualized through time resolved schlieren images, while acoustic emissions were captured through unsteady pressure measurements. Results showed a complex shock system during the starting process which includes characteristics of the bifurcated shock system, shock train, flow separation, and shock wave boundary layer interaction. In one vortex shedding cycle, vortex convection from cavity leading edge to cavity trailing edge was observed. Flow features outside the cavity demonstrated the formation and downstream movement of a λ-shock due to the interaction of shock from the cavity leading edge and shock due to vortex and generation of waves on account of shear layer impingement at the cavity trailing edge. On the other hand, interesting wave structures and its propagation were monitored inside the cavity. In one vortex shedding cycle, two waves such as a reflected compression wave from a cavity leading edge in the previous vortex shedding cycle and a compression wave due to the reflection of Mach wave at the cavity trailing edge corner in the current vortex shedding cycle were visualized. The acoustic emission from the cavity indicated that the 2nd to 4th modes/tones are dominant, whereas the 1st mode contains broadband spectrum. In the present studies, the cavity feedback mechanism was demonstrated through a derived parameter coherence coefficient.

Abstract The conformational characteristics of the deoxydinucleoside monophosphates with adenine and thymine bases in all possible sequences, namely, dApdA, dApdT, dTpdA, and dTpdT have been studied using an improved set of energy parameters to calculate the total potential energy and an improved set of energy parameters to calculate the total potential energy and an improved version of the minimization technique to minimize the total energy by allowing all seven dihedral angles of the molecular fragment to vary simultaneously. The results reveal that the most preferred conformation in all these units usually corresponds to one of the four helical conformations, namely, the A‐DNA, B‐DNA, C‐DNA, and Watson‐Crick DNA models. These helical conformations differ in energies by about 3 kcal/mol with respect to one another. The conformations which could promote a loop or bend in the backbone are, in general, less stable by about 3.5 kcal/mol with respect to the respective lowest‐energy helical conformation. The results indicate that there is a definite influence of bases and their actual sequences on the preferred conformations of the deoxydinucleoside monophosphates. The lowest‐energy structure, although corresponding to one of the four helical conformations, differ with the type of the deoxydinucleoside monophosphate. Good or reasonable base stacking is noted in dApdA and dTpdA with both C(3′)‐ endo and C(2′)‐ endo sugars and in dApdT and dTpdT with only C(3′)‐ endo sugar. The inversion of the base sequence in deoxydinucleoside monophosphates alters the order of preference of low‐energy conformations as well as the base‐stacking property of the unit. The paths linking the starting and final states in the (ω′, ω) plane show interesting features with regard to the energy spread, thus providing insight into the path of conformational movement ofthe molecule under slight perturbation. The stabilities of the A and B forms, including the internal energies of the C(3′)‐ endo ans C(2′)‐ endo sugar systems, indicate that for dTpdT the B → A transition is less probable. For dApdA, dApdT, and dTpdA this transition is probable in the same order of preference. We propose that the T‐A sequence in the polynucleotide chain might serve as the site accessible for B ⇄ A transitions. The theoretical predictions are in good agreement with the experimental observations.

&nbsp; &nbsp;&nbsp; &nbsp; &nbsp;Earthworm plays a major role in the proper functioning of the soil ecosystem. It acts as scavenger and helps in recycling of dead and decayed plant material by feeding on them. Earthworm increases the soil fertility and is often referred to as a farmer&rsquo;s friend. Earthworms have been used in medicine for various remedies. The paste prepared from earthworm, Eudrilus eugeniae was tested for antibacterial, antifungal activities. For the antimicrobial screening, four species of bacterial isolate and two species of fungal isolates were selected. The bacterial cultures were used for antimicrobial testing maintained on nutrient agar slant and the fungal strains were maintained on Sabouraud dextrose agar slant at 4&deg;C. Minimum inhibitory concentration (MIC) was determined using micro dilution broth method. Earthworm paste at a dose of 100 &micro;l was able to inhibit the growth of bacteria of S. aureus at a maximum level as compared to other bacteria; the growth of fungal Candida albicans was much inhibited. The MIC results indicated that earthworm paste at a dose of 200 &micro;l inhibited the bacterial growth. These studies may lead to the formulation of new antimicrobial drug. The antimicrobial activity of the paste was determined by an agar diffusion method using well and disc, the study clearly indicates that the paste contain a good antibacterial potential and the bioactive compounds to inhibit the growth of bacteria and fungi. Hence earthworm paste (EP) has a good potential to develop a new drug. &nbsp; Key words: Eudrilus eugeniae, antimicrobial activity, fungal and bacteria strains

Fiber-reinforced plastics (FRPs) are typically difficult to machine due to their highly heterogeneous and anisotropic nature and the presence of two phases (fiber and matrix) with vastly different strengths and stiffnesses. Typical machining damage mechanisms in FRPs include series of brittle fractures (especially for thermosets) due to shearing and cracking of matrix material, fiber pull-outs, burring, fuzzing, fiber-matrix debonding, etc. With the aim of understanding the influence of the pronounced heterogeneity and anisotropy observed in FRPs, “Idealized” Carbon FRP (I-CFRP) plates were prepared using epoxy resin with embedded equispaced tows of carbon fibers. Orthogonal cutting of these I-CFRPs was carried out, and the chip formation characteristics, cutting force signals and strain distributions obtained during machining were analyzed using the Digital Image Correlation (DIC) technique. In addition, the same procedure was repeated on Uni-Directional CFRPs (UD-CFRPs). Chip formation mechanisms in FRPs were found to depend on the depth of cut and fiber orientation with pure epoxy showing a pronounced “size effect.” Experimental results indicate that in-situ full field strain measurements from DIC coupled with force measurements using dynamometry provide an adequate measure of anisotropy and heterogeneity during orthogonal cutting.

An approach of near neighbour correlation, with manual intervention, was developed for reconstructing parent austenite microstructure in a martensitic stainless steel. This was validated in a ferrite-austenite dual structure. Two-hundred and twenty randomly selected austenite grains were reconstructed from the experimental EBSD (electron backscattered diffraction) measurements. From these reconstructions, martensite variant selection was quantified as the number of variants (nV) and the variant selection index (VSI: a statistical index for the relative area fractions of the variants). For each prior austenite grain, both nV and VSI appeared to depend on the associated transformation (austenite-martensite) strain. Selection of common variants between two neighbouring austenite grains was related to the presence of 60°<111 > or Σ3 boundary in the austenite phase and corresponding minimisation of the transformation strain.

• Uncontrolled process parameters during head forging attributed to premature failure. • Socket head hole piercing into shank results in reduction of effective bearing area. • Heterogeneity in microstructure leads further damage. • High strain rates and controlled temperature during head forging used.