bluuebunny/crossref_metadata_2025 huggingface dataset:
Peningkatan Diseminasi Informasi, Promosi, dan Citra Positif Institusi melalui Peran Duta ITS
Authors: Akbar Ida , Aditya Tama Pratino , Pratama Ohorella Putri , Mahardhika Satria
Published: December 2023

Latar Belakang: Untuk mencapai visi“Membumi untuk Mendunia”, ITS memerlukan dukungan secara nyata dari seluruh civitas akademika, tanpa terkecuali mahasiswa, yang berperan sebagai Agent of Change. Peran mahasiswa sebagai Agent of Change dinilai mampu mencerminkan citra institusi karena mahasiswa merupakan representasi dari suatu Perguruan Tinggi.

Tujuan: tujuan penulisan untuk mempertahankan citra positif institusi sebagai World Class University dan salah satu PTN-BH terbaik di Indonesia. Salah satu cara yang dapat dilakukan untuk mempertahankan citra positif institusi adalah dengan menjaring mahasiswa-mahasiswi terbaik melalui program pemilihan Duta ITS.

Metode: Penelitian ini dibuat dengan metode yang mengacu pada pemetaan program kerja ITS dan UKP, perancangan strategi sosialisasi dan promosi, hingga proses realisasinya

Hasil: kontribusi peran Duta ITS akan diwujudkan melalui program kerja yang meliputi diseminasi informasi dalam kegiatan sosialisasi dan promosi baik di dalam maupun di luar lingkungan kampus. Selain itu, peningkatan diseminasi informasi dalam kegiatan sosialisasi dan promosi untuk meningkatkan citra institusi ini sangat mendukung salah satu poin di SDG-4 yakni school enrollment, yang mana semakin baik/positif citra institusi, maka minat masyarakat untuk berkuliah di ITS akan semakin besar.

Kesimpulan: penelitian ini mampu menghasilkan luaran berupa program kerja yang dilakukan secara berkelanjutan sebagai bentuk kontribusi nyata Para Duta kepada ITS
Exploring Factors Influencing Paternal Engagement in Prenatal Health Services within Hoima East Division, Hoima City: A Comprehensive Assessment
Authors:   Faculty of Clinical Medicine and Dentistry Kampala International University Western  Campus Uganda., Patrick Jacan
Published: December 2023

Socioeconomic, cultural, and gender dynamics continue to impede women's autonomy in healthcare decision-making. Men often wield control over financial resources, time allocation, and access to medical services, creating disparities in women's health choices. This study investigated male engagement in antenatal care among residents of Hoima East Division, Hoima City in Western Uganda. Employing a cross-sectional survey design and quantitative methods, data was meticulously coded, cleaned, and analyzed using Microsoft Excel Version 13 and STATA 14.0. The study encompassed 534 participants, with a predominant age range of 21-30 years (59.4%) and a majority being married (82.2%). Most participants had completed secondary education (53.8%), identified as Catholic (41.1%), and had 3-4 children (50.1%). Results indicated that 263 individuals (69.8%) exhibited low levels of male involvement in antenatal care, while 114 (30.2%) demonstrated high levels of engagement. Notably, 54.6% displayed inadequate knowledge, contrasting with the 45.4% who exhibited a strong grasp of antenatal care. The analysis revealed significant associations between male involvement and various factors including age, marital status, educational attainment, employment status, decision-making capacity, monthly income, perception of healthcare providers' attitudes, privacy provisions at antenatal clinics, and waiting times. Despite these findings, the level of male involvement and understanding of antenatal care remained suboptimal. In summary, this research highlights the multifaceted interplay of factors influencing male involvement in antenatal care. Factors such as age, marital status, education, employment, decision-making capacity, income, healthcare provider attitudes, and clinic conditions emerged as pivotal determinants. Addressing these variables can potentially enhance male participation and knowledge regarding antenatal care, ultimately empowering women in making informed health decisions. Keywords: Antenatal care and associated factors, Attitude of health care providers, Health facilities, Maternity care, Male partners.
EU-Kommission startet Umfrage zu Online-Vermarktung von Inhalten
Authors: Gehring Robert A.
Published: December 2023

Die EU-Kommission will im neuen Jahr „die rasche, effiziente Einführung neuer Dienste und entsprechender Geschäftsmodelle für die Schaffung und Verbreitung europäischer Online-Inhalte und -Kenntnisse“ fördern. Wie sie das machen kann, will sie in einer Umfrage herausfinden.
The statistical assessment of the traffic situation based on sample data of traffic accidents in the urban agglomeration
Authors: Kushchenko L.E. , Kushchenko S.V. , Novikov A.N. , Koroleva L.A.
Published: December 2023

The article analyzes the accident rate on the roads at the entrance sections of the Belgorod agglomeration road network with the help of a documentary study of traffic accident records for the statistical assessment of the road traffic situation. It has been established that collisions and hitting a pedestrian are particular types of traffic accidents. The results of the analysis showed that Tuesday and Sunday are among the peak days of the week in terms of the probability of traffic accidents. Calculations based on mathematical statistics and probability theory have shown that there is a correlation between the number of accidents and the proposed characteristic hours of the day. To improve road safety, an information model was developed, an information model for reducing traffic accidents in places of concentration of traffic accidents.
Social evolution and commitment: Bridging the gap between formal linguistic theories and language evolution research
Authors: Matsumoto Daiki
Published: December 2023

This article argues based on some concrete empirical evidence that what is called “(social) commitment” is grammaticalized in human language at the latest stage in the evolution of syntax. It is further argued that as a result of this grammaticalization process, our ancestors acquired a way of making their linguistic communication sufficiently trustable/reliable, by encoding the signaler’s liability to the truthfulness of what is communicated. That is, the presence of commitment as a concrete grammatical element provided our species with a way of (indirectly) solving the problem of dishonesty of linguistic signals. The proposal is made in such a way that its validity can be tested by experimental means, and hence it is hoped that the model presented in this article facilitates important collaborative works among theoretical linguists, (evolutionary) biologists, and other experimentalists. Overall, the idea laid out here aims to bridge the gap between formal linguistics and language evolution studies.
Critical mineral: Zinc
Authors:   Montana Bureau of Mines and Geology, Van Rythoven Adrian
Published: December 2023

Fact sheet covering the potential in Montana for the critical mineral zinc.
Critical mineral: Ytterbium
Authors:   Montana Bureau of Mines and Geology, Davison R. , Van Rythoven A.
Published: December 2023

Fact sheet covering the potential in Montana for the critical mineral ytterbium.
Aspetar Clinical Guideline: Ramadan Fasting and Exercise for Healthy Individuals
Authors: CHAMARI Karim , AZIZ Abdul Rashid , JAMAI Tajdine Moumen , AL SAYRAFI Omar , KHALLADI Karim , BRAGAZZI Nicola Luigi , CHAOUACHI Anis , CHTOUROU Hamdi , Ben Saad Helmi
Published: December 2023

During the Islamic holy month of Ramadan, healthy adult Muslims observe fasting as an integral part of their religious practice. This dawn to dust daily fasting regimen for over 29-30 days involves strict adherence to various lifestyle aspects, including nutrition, hydration, and sleep patterns, which can potentially influence physical performance. It is often observed that Ramadan fasting may deter athletes from training and participating in competitions, and it can also discourage the general community from engaging in physical exercise. This situation can place practicing Muslim athletes at a competitive disadvantage. Therefore, the objective of this clinical guideline was to offer practical recommendations, supported by consensus from an expert panel, for healthy athletes and their support teams on how to effectively adapt their behavioural, social, and psychological strategies to cope with the changes and constraints imposed by Ramadan fasting. The scope of these recommendations extends beyond merely prescribing appropriate exercise routines during the month of Ramadan, but also encompassing considerations like scheduling, intensity, duration, exercise type, and training load. Additionally, the recommendations address various aspects of lifestyle, including nutrition, hydration, and sleep, while also delving into psychosocial and cognitive facets related to Ramadan fasting. It is important to emphasize that these recommendations are intended for healthy individuals. Patients with chronic illnesses should consult their healthcare providers to ensure that they can safely practice Ramadan fasting.
An Assessment of the Reliability and Validity of the SERVQUAL Scale in the Higher Education Context of Tanzania
Authors: Ame Ahmed M. , Tegambwage Amani M.G.
Published: December 2023

Although service quality has received increasing attention in higher education, there is lack of a standardized instrument to measure it. The most popular and widely used instrument to measure service quality across industries is the SERVQUAL scale. However, since the SERVQUAL scale was developed in the retail commercial sector, its reliability and validity for measuring service quality in the higher education sector has been questioned. This is because higher education sector differs significantly from the retail commercial sector for whichthe SERVQUAL scale was developed and widely applied. This paper assesses the applicability of the SERVQUAL scale for measuring service quality in higher education, particularly in the context of Tanzania. The data were obtained from 500 students in two public universities in Tanzania. The study found out that, the SERVQUAL scale, as modified for this study, is reliable and valid for measuring service quality in the higher education sector.Â
Assessment of Applicability of Participatory Planning in Improving Rural Livelihoods in Tanzania: The case of Utalingolo and Igosi Villages of Njombe and Wangingâ€™ombe Districts
Authors: Tonya Emmanuel M. , Mwajombe Gabriel
Published: December 2023

A study was conducted at Igosi and Utalingolo in Njombe and Wangingâ€™ombe Districts, aimed to assess the applicability of participatory planning in improving rural livelihoods. The study employed a case study approach. The study used purposive and convenient sampling techniques. Data collection instruments included questionnaires and focus group discussions. Questionnaires were administered to 50 respondents and focus group discussions were organized for the same group of people. The major findings of the study are of two categories; strengths and weaknesses.Â  Strengths: the village development committees were well represented in terms of gender and that, members were well informed on the participatory planning process. On the other part the study revealed that, the majority of the members lacked proper education, expertise in planning among the committee members, poor leadership and monitoring and evaluation techniques to established projects. The study recommended that all village members should be given mandatory training on the process of planning to.Â  Â
Diretrizes para Difusão da Língua Portuguesa pelo Brasil no Exterior
Authors: Zétola Bruno
Published: December 2023

O Itamaraty possui importante papel no processo de internacionalização da língua, cultura e economias criativas brasileiras. Seu Departamento Cultural e Educacional administra, há mais de 80 anos, uma expressiva rede de ensino de português no exterior, cuja gestão foi, recentemente, beneficiada por um amplo exercício de reflexão sobre a atuação do Ministério na difusão do idioma no exterior. Consolidada por meio de Diretrizes para Difusão da Língua Portuguesa pelo Brasil no Exterior, essa reflexão aponta princípios, vertentes, dimensões, programas e currículos para a atuação de sua rede de ensino. O corrente artigo registra o processo de reflexão dessas Diretrizes, no contexto da evolução das políticas de difusão do idioma pelo Itamaraty, bem como pelas chancelarias de outros países que dedicam especial atenção ao tema. Palavras-chave: língua portuguesa, idioma, política linguística.
Effect of Aerodynamic Heating on Separation Mechanism used in Rockets and Need of Thermal Protection for Such Structures
Authors: Sundar B. , Radhakrishnan T.V. , Joseph George , Verma A.K.
Published: December 2023

During the ascent flight of a rocket, when the vehicle passes through the dense atmosphere, the outer skin of the structure is subjected to aerodynamic heating loads. Due to this heating load, the structure is heated and .the strength of the structure deteriorates rapidly due to temperature rise of the structure. The structure needs to be thermally protected to restrict the temperature rise in order to maintain its structural integrity. However, in certain components of rockets, like in separation mechanism that is heated due to aerodynamic heating loads, the structure also needs thermal protection to minimize the large temperature gradients which if not controlled can result in thermal expansion and jamming of the separation system. Therefore it is very important to thermally protect such structures from aerodynamic heating to minimize the temperature gradients across the structure and avoid a likely mission failure. In this paper, a theoretical study is carried out to study the separation mechanism of a rocket which is subjected to aerodynamic heating. Methodology to estimate the aerodynamic heating using the actual flight trajectory of the rocket is also detailed. A l-D approach is used to estimate the temperature rise of the joint using finite difference schemes. The joint is also idealised using a 2-D finite element mesh to carry out the thermal response analysis of the mechanism. Comparison of the results of the analysis shows that a 2-D approach gives a realistic picture of the temperature distribution across the separation mechanism compared to I-D approach.
Analysis of a Marine Propeller using Panel Method
Authors: Das H.N. , Jayakumar P.
Published: December 2023

In the recent past National Science and Technological Laboratory (NSTL) has taken up work in Naval CFD for high-speed submerged vehicle and weapon applications. In this paper a problem handled at NSTL using CFD tools in conjunction with the model tests on some cases of submerged body propulsor design will be described and the advantages of such a method will be highlighted. A code developed by National Aerospace Laboratories (NAL) using constant source and doublet distributions, has been used for the analysis and the results have been compared with model tests carried out in the High Speed Towing Tank (HSTT) at NSTL.
Numerical Computation of Flow Past a Rectangular Cylinder Placed at Different Ground Clearances from a Fixed Wall
Authors: Roy A. , Bandopadhyay G.
Published: December 2023

An explicit Navier Stokes finite volume solver has been developed for calculation of flow past rectangular cylinders varying clearances from fixed ground wall. The governing equations are solved in primitive variables on a non-uniform staggered grid. The code was tested for unconfined flow past a square cylinder at various Reynolds numbers. Confined flow past a square cylinder with two different blockage ratios of l/4 and 1/6 was computed at Reynolds number 1000. Subsequently flow past rectangular cylinders of two different aspect ratios, namely, 1.0 and 2.0 have been investigated at different non dimensional ground clearances ranging from 1.0 to 5.5 at three different Reynolds numbers, namely, 250, 500 and 1000. It is found that drag increases and life becomes negative as the ground clearance decreases. The Strouhal number increases with decrease in ground clearance. Vortex shedding was observed for different combinations of aspect ratios, ground clearances and Reynolds numbers that were studied.
Application of Advanced CFD Codesf for Design and Development of Saras Aircraft
Authors: Mathur J.S. , Dhanalakshmi K. , Chakrabartty S.K.
Published: December 2023

Computational Fluid Dynamics (cfd) Is Now Able To Simulate The Jlow Past Practical Aircraft Configurations, And Can Thus Play A Very Useful Role In Aircraft Design And Developnrcnt. Cfd Codes Can Be Used To Determine The Aerodynamic Loads On Aircraft And Can Also Be Used To Studlt Crn6l Optimize The Flow Patterns And Thus Help Design An Aerddynamically Efficient Shape. This Report Describes The Applications Of The Euler Code, Juel3d, In The Analysis And Design Of The Saras Aircraft. These Applications Include The Analysis Of The Flow Past Various Configurations, From The Wing-fuselage Geometry) To The Complete Aircraft. They Als6 Include The Optimizationof The Shape Of Thewing-fuselage Junctionandthefairing Underthefuselage.
Modeling Analysis and Autopilot Design for an Airship
Authors: Pashilkar A. A.
Published: December 2023

In this paper a flight dynamic model of an airship is described. This model is used for flight mechanics analysis. A heading autopilot design has been implementedfor the airship.
''The Wright Brothers'' - The First Manned Powerjid Flight
Authors: Badrinarayan K.
Published: December 2023

No Abstract
The Dynamics of Box Beams
Authors: Chattopadhyay Lalitha , Prathap G.
Published: December 2023

Box beams bend essentially with top and bottom skins providing bending rigidity and shear webs giving shear flexibility. When the width of the beam is comparable to the length of the beam and considerably larger than the depth ofthe shearwebs, there is an added complication called the shear lag effect. The free bending vibrations of box beams can be determined analytically by incorporating shear web assumption seleclively into the Timoshenko equations so thal areas active in inertia, bending deformation and shear deformation are carefully identified. This will accountfor both shearflexibility and rotary inertia,foctors that are omitted in classical Euler- Bernoulli beam descriptions. Frequencies from these modified Timoshenko type equations qre calculated for three types of end conditions namely simply supported, clamped-free and clamped-clamped. However, no single analytical treatment is possible to accountfor the shear lag effects in the cover sheets of the box beam. Here, thefinite element method allows a computational treatment of the problem. Frequencies are therefore obtained from finite element models of wing type box beam structures. The finite element models can now include the shear lag effects, which are not sensed by the Timoshenla beam model. Comparisons show how the box beam model can serve as a bench markfor evaluatingJinite element dynamic modeling and the relativeinfluences ofshear lagand shearflexibility coupled with rotatorv inertia can be identified.
The Design of a NI-TI Based Shape Memory Alloy Actuator
Authors: Dayananda G. N. , Shankar V.
Published: December 2023

A simpffied procedure for the design of SMA(Shape Memory Alloy) actuators is presented. The inter-relationship between the mechanical properties and the electrical properties that are relevant for the design of SMA actualors working under a conEtant load are clearly brought out. The dilferent conditions that arise while using an SMA actuator against o constant load has been considered. The locus of SMA acluators in relation to conventional actuators has been clartfied. The joule heating efects and power developed by the SMA actuator in relation to its weight has been also dealt with.
Equations of State for Solid Materials Used in Aerospace and other Applications
Authors: Nagarajan V. , Venkataramanan G. , Sheshadri T.S.
Published: December 2023

High pressure studies of solids are of current imporlance. Measurements and calculations of the equation of state have been madefor a number of solids. Semi-empirical equations of state play an important role in high-pressure research. In the present work we have computed properties using the four best forms of equations of slate available in literature. We present our computed results using thefour equations of state and discuss the validity of theseforms through experimental results
A Computational Study of an Underexpanded Supersonic Jet
Authors: Pundarika G. , Lakshminarayana R. , Bhat Manjunath , Sheshadri T.S
Published: December 2023

A general code has been developed for solving the wave equation in cylindrical co-ordinate system with source distribution due to various causes to obtain a predictive capability. The advantage of this approach is that source distributions due to various causes like combustion noise, jet noise etc. can be added as and when they become available without having to change the program. One of the source distribution needed is that due to jet noise. In this work volume source distribution due to jet mixing was approximately estimated using turbulence theory. Numerical results were compared with the experimental results for C-D nozzle designed for a Mach number of two.
A CP-FDTD Preprocessor in Cartesian and Rectangular Coordinates
Authors: Vaitheeswaran S.M. , Pallavi K.P. , Murthy N.N.
Published: December 2023

In. this paper we present a versatile mesh generator in Cartesian and Rectangular co-ordinates for the Contour path Finite Difference Time Domain method wherein the grid is adjusted locally, to follow the contour of the geometric boundaries. The information about geometry, curved interfaces (dielectric/dielectric, PEC/air etc) material parameters, angles are obtained from the geometry of the intersecting interfaces at the mesh stage itself and does not need any particular area calculation for implementation at the FDTD solver stage. When run on a stair stepped or o contour path FDTD solver, the conformal approximation permits modeling of sloped and curved boundaries, while the stepped approximation permits modeling of linear material media. Additionally, to model thin layers smaller than the spatiaL step size a local sub girding approach that aLlows fine geometries to be modeled is used at the mesh stage itseLf. This means structures that are less than the grid discretization such as thin plates and small bumps are incorporated into the mesh at negligibLe costs.
Nonlinear Dynamic Analysis of Skew Laminates Using Finite Element Method
Authors: Singha M. K. , Prabhakar S. , Ganapathi M.
Published: December 2023

Here, nonlinear dynamic behavior of composite skew plates is investigated using the finite element method. The, formulation is based on shear deformation theory. The nonlinear governing equations of motion are solved using direct, iteration procedure for free vibration case, and Newmark's time integration technique is employed for dynamic response analysis. Few numerical examples are considered to highlight the influences of skew angle, fiber orientation, boundary condition and aspect ratio on the nonlinear dynamic characteristics of composite skew laminates.
Aerodynamic Modeling and System Identification from Flight Data
Authors: Jategaonkar Ravindra V.
Published: December 2023

System identification is fundamental to modeling of any observed dynamic process. This overview presentation brings out why and what system identification is as applied to flight vehicles. A historical background is briefly provided, tracing the developments to the 18th Century and early flight experiments in 1920s. Transition from classical to modern methods is brought out, highlighting the unified Quad-M approach to flight vehicle system identification that has evolved over the last three decades. Various aspects of kinematic consistency checking of recorded flight data and typical problems encountered are covered in detail. This is followed by several advanced examples pertaining to aerodynamic databases, covering (1) modeling at extreme flight conditions of large sideslip angles and stall hysteresis, (2) proof-of-match for critical flight phases, and (3) Phoenix RLV demonstrator. At the end, re-emerging aspects of recursive parameter estimation are briefly presented. The paper is concluded by indicating the possible future directions of work.
Conceptual Definition of A New Very-Light-Jet Aircraft Configuration
Authors: Yaniv Aaron , Zilberman Moshe , Pratzovnik Arie
Published: December 2023

Israel Aircraft Industries (IAI) is a world leader in the design and manufacturing of business aircraft. IAI has developed and introduced to the market several biz-jets (Westwind I and II, Astra-AKA Gulfstream G-100, and Galaxy- AKA Gulfstream G-200). All these aircraft have been in the midsize and recently "super-midsize" category. During the last two years, IAI has been evaluating a new aircraft design, the ProJet that belongs to the new, emerging category of "very-light jets" (VLJ). This lightweight twin turbofan aircraft is characterized by its small size and low target price, compared to existing IAI designs. The ProJet will be certificated to FAR23 normal category requirements, including single pilot operation. The ProJet exploits newly developed technologies and capabilities, such as: new, small and efficient turbofan engines; advanced low cost and sophisticated avionic systems; advanced low cost mechanical and electrical systems; rapid and efficient development and production methods. All these attributes will provide the capability of introducing a very low cost aircraft into the emerging new VLJ market sector. The ProJet is a twin turbofan, low wing, T-tail airplane utilizing an all-metal airframe; designed in accordance with damage tolerance requirements. It features a comfortable pressurized cabin with optimized seating for 6 occupants, including 2 pilots, and excellent performance. The ProJet will have a VFR range of 1200nm, a cruise ceiling of 41,000ft, and a cruise speed of 365kt. It will take-off and land on runways shorter than 3000ft. Generous allowance for baggage stowage is provided in the pressurized internal baggage compartment, and in the external rear baggage compartment. The ProJet flight deck features an all-glass cockpit with an integrated avionics package, designed for ease of operation and reduced workload. Composite materials are utilized in flight control surfaces and secondary structures. Two FADEC controlled turbofan engines mounted on the upper aft fuselage supply the ProJet power. Each engine generates about 1300 pounds static installed thrust at ISA +10°C.
Rolls-Royce - 100 Years of Power
Authors: Price Peter
Published: December 2023

The date of December 17th 2003 is well recognised as the centenary of the first powered flight. What is less well known is that May 4th 2004 also represented another historical centenary for aerospace. On this date in 1904, the Charles Rolls and Henry Royce first met and their drive and ambition led to the formation of this world famous company. Since that day, Rolls-Royce has established itself with a reputation for excellence and innovation across a wide range of engineering products. This presentation will explore the evolution of aero-engine development at Rolls-Royce. The story starts with the highly successful Eagle and Falcon, which dominated the Allied propulsion systems of World War I. This success was followed with the Merlin, arguably the most recognised name in aerospace engines in the 1940s, before Frank Whittle’s pioneering work led to the development of the modern jet engine. Rolls-Royce is also the world leader for the unique propulsion technologies required for both supersonic and V/STOL flight and this presentation will describe design and development of these engines. The Olympus engine, which has accrued almost one million engine flying hours on Concorde and over one billion supersonic engine miles. Rolls-Royce V/STOL experience on the innovative Pegasus engine in the Harrier has also secured a position on the LiftSystemTM, the STOVL propulsion system for the Joint Strike Fighter. Today Rolls-Royce is a world leader in gas turbine technology for civil and defence aerospace, marine and energy power systems. This presentation will describe the process of developing technology once, and using it many times which has led to the development of a broad range of the latest gas turbine engines and technologies, including EJ200, F136, Adour and RTM322 for the latest military combat, trainer and helicopter aircraft. The next 100 years in gas turbine technology is certainly going to be as challenging, new and exciting as the past century. We can expect the growth of UAVs requiring More Electric, Variable Cycle and High Mach engines as well as a wealth of unique, new propulsion systems. With over 100 years success and innovation in the aerospace power business, Rolls-Royce is ideally placed to face these challenges
Role of Radar Cross Section Facilities, In a Radar and Electronic Warfare Defence Research and Evaluation Capability
Authors: Pienaar Erlank , Ksel Thomas , Goosen Pieter , Cloete Christo , Botha Louis
Published: December 2023

This paper demonstrates the role of Radar Cross Section (RCS) facilities, consisting of modelling and simulation (M&S), Hardware in the Loop- (HWIL) and field Test and Evaluation (T&E) environments, in a Radar and Electronic Warfare (EW) Defence Research and Evaluation capability. The link between the development and utilisation of radar and EW facilities and the scientific process is illustrated by examples
Buckling of Laminated Composite Spherical Shell Cap
Authors: Sai Ram K.S.
Published: December 2023

The buckling of laminated composite spherical shell cap with and without a cutout subjected to transverse load is investigated. The geometrical non-linear analysis is carried out using the finite element method based on the first-order shear deformation theory. An eight noded degenerated isoparametric shell element with five degrees of freedom at each node is considered. The geometric non-linear behaviour and the collapse pressures with the associated mode shapes are presented for simply supported and clamped symmetrically and anti-symmetrically laminated cross-ply spherical shell cap without a cutout subjected to uniform normal pressure. The dependence of collapse pressure on the size of a central circular cutout is also studied.
Computer Aided Design Techniques for Dynamically Loaded Journal Bearings
Authors: Lakshmanan A.R , Ramasamy R.
Published: December 2023

In this paper a generalized computer aided design methodology is developed to design the dynamically loaded journal (aircraft and engine) bearings with comprehensive study. As part of procedure development a typical dynamic load case of inline engine connecting rod bearing and main bearings are taken for analysis. The determinate method of bearing force evaluation is adopted. The mobility concept is employed to predict the figures of merit (minimum film thickness, maximum film pressure). It is shown that the mobility expressions based on Goenka curve fits predict performance parameters in close agreement with data based on experiences. The entire generalized design strategy is also programmed with graphic interactions. The results are available within a few seconds from an interactive computer terminal, once initial data describing the application have been entered.
Some Practical Hints on Preservation of Aircraft Engines Using a Rig from Corrosion Problems
Authors: Vijayan Iyer Gurumurthy
Published: December 2023

Aircrafts need to be grounded for want of routine scheduled maintenance and inspection after certain period of flying hours. During such maintenance practices, the turbo-propeller engines are kept dismantled, un- installed and non-operative conditions for a longer period even up to two years. During this non-operative period, the engines and components are susceptible to extensive chronic corrosion hazards. To prevent this hazard, the engines and components are required to be preserved both internally and externally from corrosion that is the engine components such as turbine, turbine blades, compressor, fuel nozzles, fuel system pipelines, diffuser, combustion cum mixing chamber, expansion nozzle and exhaust manifold. Over the long experience of operating the aircrafts, it has been observed that the appliance provided by the manufacturer is only meant for internal corrosion preservation purposes of the operative and installed engines and cannot be used for external corrosion preservation of non-operative and un installed engines which led to drastic reduction of engine lives and unsafe operating conditions to the aircrafts due to inherent materialistic corrosive effects. The material of the turbine blades could not able to withstand its designed high combustion temperature due to the corrosion problems, which leads to unsafe engine conditions. The problem was attributable to the design factor that the high pressure cock in the fuel supply system could open and allow the preservative oil to enter into the main fuel system only when sufficient oil pressure is built up in associative oil system, which needs rotating the engines at least in idling speeds. Simulating this mandatory condition is not possible for the non-operative uninstalled engines. To overcome the corrosion hazard problem of aircraft engines, a bogie hinge joint flushing device has been designed, fabricated and tested using the local resources after taking into consideration of this important engine external preservation requirements, layout of the turbo-propeller engine power plant and fuel supply systems. This innovative external preservation rig has got multiple options coupled with internal preservation for preserving the engine components such as turbine, turbine blades, compressor, fuel nozzles, fuel system pipelines, diffuser, combustion cum mixing chamber, expansion nozzle and exhaust manifold during the course of long maintenance period. The newly designed and developed external preservation rig has resulted in achieving the complete external preservation requirements of following categories of turbo-propeller engines. a) New/overhauled engines in storage and kept on expiry of preservation life b)Installed engine required to be removed for storage but cannot be cranked or rotated c) Installed engines that are not in running condition/installation-seized engines d) Uninstalled engine for defect investigations/defect rectifications e) Non operative unsafe engines
Isentropic Swirling Flow Through Supersonic Nozzles - Part I (free Vortex Flow)
Authors: Vaidyanathan Subbaiah , Venkatesh T.N. , Krishna Mohan N
Published: December 2023

An analytical model has been developed and an approximate solution for the free vortex swirling supersonic flow through nozzles. Earlier work by Mager, is potential flow based. In the present model swirl number has been redefined to confine the flow properties within the valid range. Flow properties are always determined by the total conditions (P0 and a0), nozzle profile and swirl intensity as in the case of one-dimensional flow. Integral form of the continuity equation has been used in order to satisfy the boundary conditions, since radial velocity component is ignored. For free vortex case, it has been shown that there exists a minimum radius along the length of the nozzle at which the density is zero and flow seems to be void causing reasonable blockage to the flow at throat. In defining the non-dimensional swirl number (β), axial velocity at each section was employed for non-dimensionalization as compared to Mager’s definition of using a global constant to find swirl number (α). The variations of performance parameters of the nozzle such as co-efficient of discharge (Cd) thrust efficiency (ηs) and impulse efficiency (ηI) and flow field parameters such as density, pressure, velocity etc. are presented as a function of swirl numbers (α, β) and compared with the available experimental data. The swirl numbers (α, β) are also correlated.
Wind Tunnel Investigation of Typical Strategic Missile Configuration at High Angle of Attack
Authors: Ghosh A.K. , Sagoo Girish , Singhal Ankur
Published: December 2023

The present wind tunnel investigation is a part of a project studying the effectiveness of flat fin control on short-range strategic missile at high angle of attack. As a part of this program, the longitudinal aerodynamic coefficients were computed analytically and were compared with estimates obtained through wind tunnel testing. Wind tunnel tests were conducted over a range of angle of attack from -15° to +45° at a free stream speed of 60m/s. Aerodynamic coefficients were generated for various missile configurations. These coefficients were then compared with the estimates obtained analytically. It was conjectured that, at high angle of attack, vortices shaded by the body interact with the local flow near the fins and drastically alters the stability characteristics of the missile. The subject missile has a small hemispherical nose as compared to most of the missiles having conical or ogival nose. For such a configuration sufficient theoretical/experimental data are not available. Thus, it was important to generate longitudinal aerodynamic data for the range of angle of attack upto which the theoretical model can be used to evaluate the aerodynamic stiffness of the missile. Such a model structure is required for postulating aerodynamic model in estimation algorithm, used for parameter estimation from flight data of the subject missile.
Dynamics Of Indo-us Space Co-operation
Authors: Abdul Kalam A.P.J.
Published: December 2023

Now, let me recall one event that took place four decades ago in Thumba, a small fishing village where the India’s space research programme was born. Let me describe the event at the payload integration laboratory. It was a round the clock operation for many weeks. Three space teams, two dealing with scientific payloads and the other dealing with rocket, payload and system integration were on the site. The rocket and payload team consisted of Robert Bessel from GSFC, Robert Duffy, Director, Wallops Island test range, Mr. Madhavan Nair, presently Chairman ISRO and myself. I was a rocket engineer at that time. The second team consisted of Prof. Blamount from CNES, France and Prof. P.D. Bhavsar, PRL, India for the Sodium Vapour experiment to study the upper atmospheric structure. The third team was of Prof. Satyaprakash for the Langmuir probe experiment to measure electron density in E-Layer. The Nike Apache rocket with this payload was launched successfully from Thumba equatorial rocket launching station. The flight data was monitored with multiple cameras, telemetry and radar stations. It was a beautiful successful experiment with the cooperation of three nations. India - USA - France. Today India has the capability to build many
Neural Network Based Three Axis Satellite Attitude Control Using Only Magnetic Torquers
Authors: Sivaprakash N. , Shanmugam J.
Published: December 2023

Magnetic actuation utilizes the mechanic torque that is the result of interaction of the current in a coil with an external magnetic field. A main obstacle is, however, that torques can only be produced perpendicular to the magnetic field. In addition, there is uncertainty in the Earth magnetic field models due to the complicated dynamic nature of the field. Also, the magnetic hardware and the spacecraft can interact, causing both to behave in undesirable ways. This actuation principle has been a topic of research since earliest satellites were launched. Earlier magnetic control has been applied for nutation damping for gravity gradient stabilized satellites, and for velocity decrease for satellites without appendages. The three axes of a micro-satellite can be stabilized by using an electromagnetic actuator, which is rigidly mounted on the structure of the satellite. The actuator consists of three mutually orthogonal air-cored coils on the skin of the satellite. The coils are excited so that the orbital frame magnetic field and body frame magnetic field coincides i.e. to make the Euler angles to zero. This can be done using a Neural Network controller trained by PD controller data and driven by the difference between the orbital and body frame magnetic fields.
Accelerated Flight Envelope Expansion Using Near Real Time Stability Margin Estimation
Authors: Patel Vijay V. , Deodhare Girish , Chetty Shyam
Published: December 2023

A novel technique for estimating the stability margins in near real time has been developed by the authors [1]. This paper shares the invaluable flight test experience gained in using it for flight envelope expansion of India’ s first digital fly-by-wire Light Combat Aircraft (LCA). Use of this technique has resulted in reducing the overall flight test effort and cost without compromising safety.

Using the technique, it was possible to estimate the stability margins on a desktop computer using real time telemetry data within approximately 60 seconds of completing the test. The flight test results for ‘Fixed’ (restricted flight envelope) and ‘Scheduled’ (full flight envelope) gain control laws, for manually generated pilot 3-2-1-1 inputs and pre-programmed 3-2-1-1 inputs generated using the onboard Flight Test Panel (FTP) are presented.

During the LCA flights, the stability margins were found to be satisfactory throughout the flight envelope. In order to establish that the same technique would work equally well when the stability margins are marginal, typical results were also generated using simulation data and are included in this paper. By artificially increasing the plant gain / delay in the simulation model it is shown that even if the stability margins are low, the same technique correctly estimates the relative stability.
Effect of Diffuser Vane Height and Position on Diffuser Wall Static Pressures in a Centrifugal Compressor
Authors: Sitaram N. , Issac J. M. , Govardhan M.
Published: December 2023

The present paper reports experimental investigations on the effect of diffuser vane height and its position on diffuser wall static pressures of a low speed centrifugal compressor. Apart from the standard types of diffusers, namely, vaneless, vane and low solidity vane diffusers, a partial vane diffuser, whose height is less than the diffuser width is also tested. The vane height of the partial vane diffuser is varied from 0.3, 0.4 and 0.5 times the diffuser width in vane and low solidity vane diffuser configurations. In addition, the effect of vane position is examined by fixing the partial vanes to the hub, shroud or hub and shroud. It is found that there is an optimum height for the diffuser vane height, which is found to be 0.3 times the diffuser width. The effect of position of the partial vanes on the hub or shroud on the diffuser wall static pressures is found to be negligible. However when partial vanes are fixed on the hub and shroud staggered at half spacing, the diffuser performance based on wall static pressures is improved substantially.
Analytical Sensitivity based Guidance Algorithm for Reusable Launch Vehicles
Authors: Joshi Ashok , Sivan K. , Amma Savithri
Published: December 2023

The present study is aimed at the development of an accurate and robust reentry guidance strategy for Reusable Launch Vehicles (RLVs), based on onboard trajectory planning and by using the concept of analytical sensitivities. The onboard planning algorithm generates a feasible trajectory from any reentry interface to specific target location, while satisfying all the path constraints, prior to the start of the reentry. For this purpose, the optimal control problem of reentry guidance is converted into an equivalent targeting problem in Nonlinear Programming and a simple solution methodology is devised to generate the three-dimensional trajectory. The profile tracking algorithm is developed based on the well known Linear Quadratic Regulator technique. In this strategy, equations of motion are described in polar coordinates and a direct analytical method for computation of sensitivity matrix elements is used, which ensures better mission planning and faster convergence. An additional feature of the proposed algorithm is the inclusion of an integral term in control law, which tracks the trajectory without a need for instantaneous bank reversals, even with a dispersed environment. The performance results establish adequacy and usefulness of the algorithm.
Development and Tuning of a Nonlinear Six DOF Model and Controllers for a Large UAV
Authors: Balaji P. Jagadeesh , Kumar K. Senthil , Shanmugam J.
Published: December 2023

This paper presents development of non-linear six-degree-of-freedom model for a large UAV and simulation of its dynamics during its landing phase. A non-linear six-degree-of-freedom aircraft model was developed using the block available in the Aerosim Aeronautical Simulation Blockset in MATLAB / SIMULINK environment. The aircraft parameter data for a large UAV was taken. The developed model could be used for simulating the dynamics of the UAV with single piston engine and fixed pitch propeller. The following controllers were tuned using the above model to simulate its landing phase. ‘Bank to Aileron’, ‘Airspeed error to Pitch command’, ‘Pitch error to Elevator deflection’, ‘Engine rpm error to Throttle’. The first approach was by conventional techniques using PI and PID controllers. In the next stage fuzzy logic controllers were designed for the above cases. All fuzzy controllers were designed using Mamdani inference system.
Vision for Aerospace 2020
Authors: A.P.J. Abdul Kalam
Published: December 2023

no abstract
Postbuckling Characteristics of Angle-Ply Laminated Joined Conical-Cylindrical-Conical Circular Shells
Authors: B.P. Patel  , S. Singh  , Y. Nath
Published: December 2023

The postbuckling behaviour of angle-ply composite laminated joined circular conical-cylindrical- conical shells, subjected to external pressure, torsion, axial compression and thermal loading, is studied considering the variation of stiffness coefficients along the meridional direction in the conical sections. The analysis is carried out using the semi-analytical finite element method based on first-order shear deformation theory. The nonlinear governing equations are solved using Newton-Raphson iterative technique coupled with the displacement control method. An asymmetric perturbation in the form of a small magnitude load spatially proportional to the linear buckling mode shape is considered. The effect of semi-cone angle and number of circumferential waves on the prebuckling/postbuckling response of angle-ply laminated joined circular conical-cylindrical-conical shells is investigated. The effect of inclusion of rotation about normal to the middle surface in the strain-displacement relations is also studied
Step Pdm Schema Based Product Structure Manager For Collaborative Assembly Modeling
Authors: V.K. Janardanan  , M. Adithan  , P. Radhakrishnan
Published: December 2023

In this paper a STEP PDM Schema based Product Structure Manager is presented that enables designers to hold virtual meetings via the Internet and allows collaborative viewing, modify product structure and annotate the 3D model. This Product Structure Manager provides a shared platform for the designers. Two specific factors have been incorporated in developing the Product Structure Manager. Firstly heterogeneous application systems are being used by designers and secondly geographically dispersed designers and team members. In this context, STEP standard has accordingly utilized to address the issue of heterogeneous application systems and the Product Structure Manager has been developed as a Web-based module to integrate the designers. A case study has been carried out with this developed architecture for assembly modeling of a launch vehicle system called LHRS. LHRS is a system, which holds the launch vehicle in the launch pad and safeguards the vehicle without toppling due to ground wind and other off nominal lift off conditions.