bluuebunny/crossref_metadata_2025 huggingface dataset:
Systemic Inflammatory Marker Levels in Serous Macular Detachment Secondary to Retinal Vein Occlusion
Authors: Doğan Emine , Gündoğdu Kübra Özata , Bursalı Özlem , Çelik Erkan , Alagöz Gürsoy
Published: June 2024

Purpose:

To evaluate the association of systemic inflammatory marker levels in macular edema with serous macular detachment (SMD) secondary to retinal vein occlusion (RVO).

Methods:

Patients diagnosed with RVO were categorized into two groups based on the presence or absence of SMD: Group 1 included 30 eyes with SMD, while Group 2 included 30 eyes without SMD. Levels of neutrophils, monocytes, lymphocytes, thrombocytes, and mean platelet volume (MPV) were analyzed. Systemic inflammatory markers, including neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII), were calculated and compared between the two groups.

Results:

The mean neutrophil levels were significantly higher in Group 1 (P = 0.002). The mean lymphocyte, monocytes, thrombocyte, and MPV levels did not differ significantly between groups. NLR and SII levels were significantly higher in the SMD group (P = 0.004 and P = 0.016, respectively). There was no significant difference between the groups in terms of PLR. The optimal receiver operator characteristic (ROC) cut-off value of NLR for SMD was calculated as 1.55 with 73% sensitivity and 63% specificity (area under the curve [AUC] = 0.714, 95% confidence interval [CI]: 0.584–0.845). The optimal ROC cut-off value of SII for SMD was calculated as 451.75 with 63% sensitivity and 63% specificity (AUC = 0.681, 95% CI: 0.546–0.816). In this study, branch RVO was present in 48 patients, and central RVO was present in 12 patients. Neutrophil, MPV levels, and NLR, PLR, SII ratios were similar between patients with branch and central occlusion.

Conclusion:

Neutrophil levels, NLR, and SII were found to be significantly higher in eyes with SMD secondary to RVO.
Resident-Performed Phacoemulsification Cataract Surgery: Impact of Resident-Level Characteristics
Authors: Karimi Saeed , Arabi Amir , Shahraki Toktam , Javadi Mohammad Ali , Safi Sare
Published: June 2024

Purpose:

To evaluate the rate of complications in resident-performed phacoemulsification and influencing factors.

Methods:

In this retrospective cohort study, the outcomes of cataract surgeries performed by 18 ophthalmology residents were analyzed. The outcome of first 80 phacoemulsification cataract surgeries (1440 cataract surgeries) performed by each resident were analyzed. Outcome measures included the rate of intraoperative capsular rupture requiring anterior vitrectomy, nucleus drop, and incomplete attempts at uncomplicated procedures. Changes in the rate of complications over the surgical training course were also assessed.

Results:

The most common surgical complications were capsular rupture (7.5%), followed by incomplete attempt(s) (5.9%), and nucleus drop (1.1%). Comparing the first 40 and second 40 surgeries, the rate of complications decreased as a function of surgeon experience in all resident cohorts. Greater theoretical skills and younger surgeon age were associated with a lower rate of intraoperative capsular rupture (hazard ratios = 1.421 and 1.481, respectively; P = 0.047 and P = 0.041, respectively). The use of antianxiety drugs and number of surgeries in the first 6 months demonstrated no predictive value for a lower rate of intraoperative complications (hazard ratios = 0.929 and 1.002; P = 0.711 and P = 0.745, respectively).

Conclusion:

The use of antianxiety medication and more surgeries in the first 6 months did not decrease the rate of intraoperative complications of phacoemulsification, while improvement of theoretical skills may have increased the safety of resident-performed cataract surgery.
Association of Risk Factors among Nasal and Orbital Mucormycosis in Coronavirus Disease 2019 Infection
Authors: Vidhyadevi Ramasamy , Saudhamini S. , Padmanaban Sundaram , Sundar Devisundaram , Kannappan Suvetha , Suryaprabha Gopalsamy
Published: June 2024

Purpose:

To study the risk factors of mucormycosis and analyze their association among nasal and orbital mucormycosis in Coronavirus disease 2019 (COVID-19) infection.

Methods:

All patients diagnosed of rhino-orbito-cerebral mucormycosis (ROCM) with previous COVID-19 infection were included in the study. The details such as age, sex, presence of co-morbidities, and serum ferritin levels were collected. ROCM patients were classified into two groups, nasal mucormycosis (stage 1 and 2 of ROCM) and orbital mucormycosis (stage 3 and 4 of ROCM), and data were collected. Duration of COVID-19 symptoms, the time interval between COVID-19 infection and onset of ROCM symptoms, computed tomography severity score (CTSS) and usage of steroids were collected accordingly. The collected data were compared between nasal group and orbital group.

Results:

Among 52 patients, 15 patients had nasal and 37 patients had orbital mucormycosis. Forty-one patients were more than 40 years, 43 patients were males. Seven out of ten risk factors were found to be significant on comparing nasal and orbital group. Patients of age more than 40 years (P = 0.034), elderly diabetics (P = 0.014), poor control of diabetes (P = 0.003), high serum ferritin levels (P = 0.043), duration between COVID-19 and mucormycosis of more than 20 days (P = 0.038), CTSS of more than 9/25 (P = 0.020), and steroid usage during COVID-19 infection (P = 0.034) are prone to develop orbital mucormycosis. On multivariate logistic regression analysis, these variables did not emerge as independent risk factors.

Conclusions:

Patients with severe COVID-19 infection along with other associated risk factors can be prone to develop severe forms of mucormycosis. We did not find them to be statistically significant on multivariate analysis. In the future, large scale studies are needed to know their significance.
Expert Opinion on Fixed Dose Combination of Dapagliflozin Plus Sitagliptin for Unmet Cardiovascular Benefits in Type 2 Diabetes Mellitus
Authors: Ray Soumitra , Ezhilan J , Karnik Rajiv , Prasad Ashish , Dhar Rajashree
Published: June 2024

Type 2 diabetes mellitus (T2DM) is known to be associated with macrovascular (coronary heart disease, stroke, and peripheral arterial disease) and microvascular complications (diabetic kidney disease, retinopathy, and peripheral neuropathy). The coexistence of T2DM with established/risk of atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), or chronic kidney disease confers a poor prognosis, and management can be challenging. Guidelines recommend clinicians to consider CV/HF risk, renal/hepatic risk, and other comorbidities while choosing an antidiabetic regimen. The fixed dose combination (FDC) of sodium-glucose cotransporter-2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors provides both glycemic and pleiotropic effects, including lower risk of hypoglycemia, lower rates of genitourinary tract infections, and weight neutrality. Based on CV risk, including HF, the combination of SGLT2i and DPP4i may be preferred over other conventional therapies (those with no CV benefit) in cases of established CV disease and/or HF risk. The Indian expert consensus group discussed the literature, clinical benefits, and the role of the FDC of Dapagliflozin and Sitagliptin for the unmet cardiovascular benefits in T2DM patients. This practical guidance document would support general physicians, endocrinologists, diabetologists, cardiologists, and nephrologists in selecting the appropriate regimen for superior patient outcomes.
Short Chronic Total Occlusion Stump Creating an Optical Illusion of an Anomalous Coronary Artery
Authors: Sahu Ankit Kumar , Sagar Pramod , Tewari Satyendra , Kapoor Aditya
Published: June 2024

Coronary artery anomalies are often asymptomatic and detected incidentally during coronary angiography, cardiac surgery, or autopsy. However, sometimes in chronic total occlusion, the distal part of a vessel is well collateralized from the contralateral vessel that it appears almost as an anomalous coronary artery. Here, we discuss a rather interesting angiogram which at first instance, looked like a case of a dual left anterior descending (LAD) artery with anomalous origin of the LAD from the proximal right coronary artery, but after further evaluation appeared to be a case of an occluded LAD filling through Vieussens' arterial ring.
Energy Consumption in Lightweight Electric Aircraft
Authors: Kanchagar Amogha
Published: June 2024

Electric aircraft have emerged as a promising solution for sustainable aviation, aiming to reduce greenhouse gas emissions and noise pollution. Efficiently estimating and optimizing energy consumption in these aircraft is crucial for enhancing their design, operation, and overall performance. This paper presents a novel framework for analyzing and modeling energy consumption patterns in lightweight electric aircraft.

A mathematical model is developed, encompassing key factors such as aircraft weight, velocity, wing area, air density, coefficient of drag, and battery efficiency. This model estimates the total energy consumption during steady-level flight, considering the power requirements for propulsion, electrical systems, and auxiliary loads. The model serves as the foundation for analyzing energy consumption patterns and optimizing the performance of lightweight electric aircraft.

To facilitate analysis and visualization of energy consumption patterns, the study includes the development of Python and MATLAB codes. The Python code simulates the energy consumption of a single-pilot electric aircraft, allowing for the assessment of the impact of flight duration on total energy consumption during steady-level flight. This provides insights into the energy efficiency of various electric aircraft designs. Additionally, the MATLAB code and MATLAB Simulink model generates graphical representations of energy consumption trends over varying flight durations, enabling visual analysis and interpretation of the data.

The analysis and simulations conducted using the framework yield valuable insights into the power requirements and energy consumption patterns of lightweight electric aircraft. These findings contribute significantly to the ongoing efforts in advancing electric aviation, providing a robust framework for energy consumption assessment and optimization.

In conclusion, this paper offers a unique approach for analyzing and modeling energy consumption in lightweight electric aircraft. By utilizing the mathematical model, Python code, MATLAB code and MATLAB Simulink Model, researchers and engineers can evaluate and optimize the energy efficiency of electric aircraft designs, promoting range extension, endurance increase, and operational cost reduction.
Thermal Analysis of Prismatic Core Sandwich Structural Panel for Hypersonic Application
Authors: Mukherjee Ragini , Roy Mahapatra Debiprosad
Published: June 2024

Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. However, structural integration has significant challenges due to extreme aero-thermo-mechanical coupled effects. Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation. An active cooling thermal protection system for scramjet applications has the highest potential for thermal load management, especially for long-duration flights, considering the weight penalty associated with the heavier passive thermal insulation structures. We consider the case of active cooling of scramjet engine structural walls with endothermic hydrocarbon fuel. We have developed a semi-analytical quasi-2D heat transfer model considering a prismatic core single cooling channel segment as a representative volume element (RVE) to analyse larger-scale problems. The model includes various mechanisms of heat transfer as well as the coolant’s energy transport (non-cracking fuel). Using this model, we aim to study the effect of active cooling on the system's thermal behaviour and heat transfer characteristics. The model predicts the temperature distribution in the channel and the interfaces. Parametric analysis is undertaken to assess the active cooling system design parameters which affect the heat transfer characteristics of the system. Such semi-analytical models help investigate the effect of the cooling channel geometry and flow parameters, which can be a decisive prerequisite to the configuration design of a scramjet engine.
Elastomeric Swaging Finite Element Analysis Methodology to Evaluate Structural Integrity of Internal Swaged Joints
Authors: Sandhu Taranjeet , Aher Ravi , Soni Ravi , Barsawade Nikhil , Kamthe Swapnil , Sajjan Phalle Vijay
Published: June 2024

In applications demanding high performance under extreme conditions of pressure and temperature, a range of Mechanically Attached Fittings (MAFs) is offered by various Multinational Corporations (MNCs). These engineered fittings have been innovatively designed to meet the rigorous requirements of the aerospace industry, offering a cost-effective and lightweight alternative to traditional methods such as brazing, welding, or other mechanically attached tube joints.

One prominent method employed for attaching these fittings to tubing is through Internal Swaging, a mechanical technique. This process involves the outward formation of rigid tubing into grooves within the fitting. One of the methods with which this intricate operation is achieved is by using a drawbolt - expander assembly within an elastomeric swaging machine. Traditionally, elastomeric swaged joints find extensive application among Aerospace Industry Original Equipment Manufacturers (OEMs) and are compatible with materials like Titanium, Aluminum, and Stainless Steel, accommodating various tube wall thicknesses.

To optimize the design of elastomeric swaged joints and manufacturing process, a Finite Element Analysis (FEA) methodology has been developed utilizing the licensable Abaqus software. This methodology simulates the intricate cold forming operation of elastomeric swaging, thereby establishing a robust correlation between FEA and physical testing results. This correlation addresses critical quality parameters such as structural integrity and mechanical strength, aiding in the optimization of swaging parameters, minimizing testing requirements, and significantly reducing the overall lead time for the development of new swaged joints.
Effect of Fatigue Loads on behavior of 2024 Aluminum for Aircraft Hydraulic Applications
Authors: Paidimarri Vishal , Jacob Krupa , Harish Uppu , Hovis David
Published: June 2024

Hydraulic systems in aircraft largely comprise of metallic components with high strength to weight ratios. Some examples of such material include Aluminum and Titanium alloys which are typically chosen for low and high-pressure applications respectively. For aircraft fluid conveyance products, hydraulic conduits are fabricated by axisymmetric turning to support flow conditions. The hydraulic conduits can have grooved interfaced design within for placement of elastomeric sealing components. This article presents a systematic study carried out on common loads experienced by fluid carrying conduits and the failure modes induced. Firstly, a static structural analysis was carried out on each of the geometries of the test articles to identify the locations having areas of high stress concentration. Test articles of various wall thicknesses and internal diameters were pressure impulse tested at different conditions of side loads to identify cycle numbers till failure and failure locations. On the test articles that structurally failed, the failure locations were identified, and the Scanning Electron Microscope (SEM) analysis was carried out to identify the characteristic footprints of failure surfaces and crack initiation. A comparison done between parameters influencing fatigue life like alternating stress, stress concentration factor and backup material show fairly good trends in accordance with first principles. However, the authors note and appreciate a few data points that deviate from expected trends and through this paper an attempt is made to explain the interplay of said parameters leading to the deviation. It was established that side & lateral plug loads have a significant contribution and influence on failure as opposed to hoop loads which are common in aerospace hydraulic components. It was concluded that the presence of axially misaligned cyclical loads caused reduction of fatigue life on axisymmetric adapters of at least 40K and the absence of the same improved fatigue life by almost 200K. Through the findings of this study it is concluded that a complex interplay between material stiffness, amplitude of alternating stress and stress concentration factor influences how the material responds to cyclic loading.
Design and Development of Terminal Velocity Measurement System for Descending Modules
Authors: Girish Gayathri , KS Smitha , M P Rizwana , K Anand
Published: June 2024

During landing of re-entry modules in manned missions, one of the most critical parameters to be monitored is its terminal velocity. As human safety is prioritized in manned missions, the module’s maximum permissible terminal velocity values are pre-determined based on the human tolerance levels. The entire deceleration system of the module is then optimized for achieving terminal velocities below these limits to ensure safe touchdown of the crew. In addition to vertical velocity, the module also experiences lateral and rotational velocities during its descent. Characterizing these velocities lead to a more comprehensive understanding of the dynamics faced by the module while landing. Therefore, acquiring accurate in-flight velocity data is a fundamental requirement for Gaganyaan missions. Existing methods for measuring terminal and lateral velocities have limitations in terms of accuracy, feasibility, and cost-effectiveness. In response to the need for an accurate and precise measurement of tri-axial velocities, Terminal Velocity Measurement System (TVMS) is developed. TVMS harnesses state-of-the-art Doppler radar technology to provide tri-axial velocity with a high update rate. Primarily, TVMS consists of Doppler radar sensors for measuring the Doppler shift due to deceleration. By employing three radar sensors, TVMS guarantees the measurement of both terminal and lateral velocities. Doppler frequency output is processed into velocity data by a microcontroller and associated electronics integrated onto a compact card. TVMS frequency-processing card was developed and subjected to rigorous testing which exhibited highly promising results. It offers both analog as well as digital outputs, enabling seamless telemetry to ground stations to meet mission requirements. Thus, TVMS ensures the precise measurement of tri-axial velocity, thereby enhancing the safety and reliability of manned missions. It promises to set a benchmark for other velocity measurement methods and offers immense potential in future space exploration endeavors.
High Payload Fraction UAV Design and Performance Evaluation
Authors: G Chandana , Gowda G Shashank , Sayeeganesh Adithya , Vannarth Ram Rohit
Published: June 2024

Unmanned Aerial Vehicles (UAVs), or drones, are aerial platforms with diverse applications. Their design is shaped by specific constraints, driving a multidisciplinary, iterative process encompassing aerodynamics, structures, flight mechanics and other domains. This paper describes the design of a fixed-wing UAV tailored to competition requirements. The requirements included maintaining a thrust-to-empty weight ratio of less than 1 and achieving a high payload fraction, calculated as the ratio of payload weight to total UAV weight. A modified sizing approach was introduced, altering the conventional UAV sizing process to enhance the payload fraction. This was achieved by adjusting the design points within the solution space derived from constraint analysis. Furthermore, a novel structural optimization method was applied, utilizing critical points from the V-n diagram as design points, where the primary emphasis was on reducing the airframe weight while ensuring an acceptable level of safety. Additionally, a novel method for the endurance performance estimation of the UAV was developed, integrating the concept of weighted fraction. The design of each component was done through a general iterative process, with the constraints being the requirements and the assumptions made in the sizing process. Aerodynamic coefficients were determined via the vortex particle wake method using flow5 software. A mathematical model, employing state space representation, assessed dynamic characteristics at the trim position. Stability analysis confirmed UAV stability in both static and dynamic conditions. The flight test of the prototype validated the design, demonstrating the UAV’s ability to achieve the intended payload fraction with good controllability and stability.
Numerical Investigation of the Aerodynamic Characteristics of a Missile Geometry at Mach 4
Authors: Padmanabha M Ananth , Prasad Bhoomika , Sivasubramanian Jayahar
Published: June 2024

The aim of this paper is to present a numerical analysis of high-speed flows over a missile geometry. The N1G missile has been selected for our study, which is subjected to a high-speed flow at Mach 4 over a range of Angle of attack (AoA) from 0° to 6°. The analysis has been conducted for a 3-dimensional missile model using ANSYS environment. The study contemplates to provide new insights into the missile aerodynamic performance which includes the coefficient of lift (CL), coefficient of drag (CD) and coefficient of moment (CM) using computational fluid dynamics (CFD). As there is a lack of availability of data for missile geometries, such as free stream conditions and/or the experimental data for a given Mach number, this paper intends to provide a detailed analysis at Mach 4. As the technology is advancing, there is a need for high-speed weapons (missiles) with a good aerodynamic performance, which intern will benefit in reduction of fuel consumption. In order to meet the requirements, aerodynamic shape optimization can be performed. This paper will create a basic knowledge about the N1G missiles aerodynamic performance at Mach 4. This can be referred in future studies into the hypersonic regime and shape optimization to get the best suited geometry with high aerodynamic performance for a given free stream condition.
Enhancing Sustainable Aviation through Contrail Management – A Framework for Multiple Platforms
Authors: Adavalath Puthiyaveettil Sayooj , Padmanabhan Suresh , HoskoteHanumanthaRao Bhargav
Published: June 2024

Effective contrail management while ensuring operational and economic efficiencies for flight services is essential for providing services with minimal adverse environmental impact. The paper explores various aspects of contrail management applicable to different platforms such as Unmanned vehicles, Commercial airliners, and Business & regional jets. The aspects unique to each platform such as flight levels of operation, fuel types, flight endurance and radius of operation have been analyzed. Expanse of 5G network is resulting in increased flight activity at flight levels not envisaged hitherto. The paper also dwells on the ramifications of the increased proliferation of different platforms at newer flight levels from the perspective of contrail management. This paper introduces a framework that integrates the dual objective of minimizing contrail effects while optimizing fuel consumption for commercial aircraft by considering various factors like flight levels, geothermal data, and flight time. The paper also examines challenges and strategies related to seamless implementation, thereby highlighting the framework’s potential to propel the aviation industry towards environmentally responsible and efficient practices.
Numerical Investigation of Aerodynamic Characteristics on a Blunt Cone Model at Various Angles of Attack under Hypersonic Flow Regimes
Authors: Deka Sushmita , Kamal Abhishek , Patra Sanjukta , Sahoo Niranjan
Published: June 2024

The study of aerodynamic forces in hypersonic environments is important to ensure the safety and proper functioning of aerospace vehicles. These forces vary with the angle of attack (AOA) and there exists an optimum AOA where the lift to drag force ratio is maximum. In this paper, computational analysis has been performed on a blunt cone model to study the aerodynamic characteristics when hypersonic flow is allowed to pass through the model. The flow has a Mach number of 8.44 and the AOA is varied from 0° to 20°. The commercial CFD solver ANSYS FLUENT is used for the computational analysis and the mesh is generated using the ICEM CFD module of ANSYS. Air is selected as the working fluid. The simulation is carried out for a time duration of 1.2 ms where it reaches a steady state and the lift and drag forces and coefficients are estimated. The pressure, temperature, and velocity contours at different angles of attack are also observed. It is found that the lift-to-drag ratio increases with increasing angle of attack up to a certain value and then reduces drastically. The optimum AOA is found at 17° where it has the maximum ratio of lift force to drag force. This study helps in understanding the aerodynamic and stability characteristics of hypersonic vehicles at various angles of attack that is significantly different from those of the subsonic or supersonic vehicles.
Dynamic Ascent Loads Estimation of Winged Reusable Launch Vehicle: Formulation, Analysis and Post Flight Studies
Authors: Jayan Mahind , Pavanasam Ashok  Gandhi , Daniel Sajan
Published: June 2024

A structural load estimation methodology was developed for RLV-TD HEX-01 hypersonic experimental mission, the maiden winged body technology demonstrator vehicle of ISRO. Primarily the method evaluates time history of station loads considering effects of vehicle dynamics and structural flexibility. Station loads of critical structures are determined by superposition of quasi-static aerodynamic loads, dynamic inertia loads, control surface loads and propulsion loads based on actual physics of the system, improving upon statistical load combination approaches. The technique characterizes atmospheric regime of flight from vehicle loads perspective and ensures adequate structural margin considering atmospheric variations and system level perturbations. Features to estimate change in loads due to wind variability and atmospheric turbulence are incorporated into the load estimation methodology. Augmentation in loads due to structural flexibility is assessed along the trajectory using vehicle states calculated by a flexible vehicle response solver integrated to 6-DOF trajectory solver. This methodology was used to authorize the successful maiden launch of RLV-TD HEX-01 flight on May 23, 2016. The paper describes basic formulation of elastic load estimation technique, pertinent mission design simulation studies and comparison of estimated load with flight measured data. A close agreement between computed structural load and flight measured load throughout the atmospheric regime of flight demonstrates technological maturity of the methodology.
Configuration and Design of Mobile Checkout System for Ground Testing of Reusable Launch Vehicle
Authors: V Vivekanand
Published: June 2024

The winged body reusable launch vehicle needs to be tested and evaluated for its functionality during the pre-flight preparation at the runway. The ground based checkout systems for the avionics and the actuator performance testing during pre-flight evaluation are not designed for rapid movement. This new kind of launch vehicle with solid rocket first-stage and winged body upper-stage demands the system testing at Launchpad and at the runway. The safety protocol forbids the permanent structure for hosting the checkout system near runway. The alternative is to develop a rapidly deployable and removable checkout system. A design methodology adopting conventional industrial instrumentation systems and maintaining mobility is presented. This paper presents the design and development of a mobile checkout system for supporting the ground pre-flight testing during autonomous flight landing trials.
Stability of Hypersonic Boundary Layers on Flat Plates with Sharp and Blunt Leading Edges
Authors: Mehta Urvi Sanjiv , Sivasubramanian Jayahar
Published: June 2024

This research employs a comprehensive methodology to explore the stability and transition dynamics of hypersonic boundary layers, focusing specifically on the influence of sharp and blunt leading edges. The Stanford University Unstructured (SU2) Computational Fluid Dynamics (CFD) solver is utilised to compute the mean flow over a flat plate, establishing a foundational basis for subsequent stability analysis. The extracted boundary layer profiles undergo validation against existing literature, ensuring accuracy and reliability. The linear stability Solver analysis constitutes a crucial phase wherein the research focuses on the eigenvalue spectra, identifying dominant modes and closely scrutinising the transition process within the hypersonic boundary layers. This investigation into stability characteristics is paramount for designing and optimising hypersonic vehicles, providing valuable insights to enhance their efficiency and security. By comprehending the intricate interplay between sharp and blunt leading edges and stability, the research contributes to formulating predictive models, simulations, and control strategies. These strategies aim to mitigate the disruptive effects of instability, ultimately elevating hypersonic vehicles' overall performance and safety. The study's outcomes advance our understanding of the complex relationship between the radius of leading edges and hypersonic boundary layer stability and pave the way for tangible advancements in hypersonic vehicle design and operation, offering valuable contributions to developing safer and more efficient hypersonic vehicles.
Development of INLS 3U Uni-Pod Nano Satellite (CubeSat) Dispenser System for 3U Class Satellites
Authors: Paul Johns , PM Abdul Salam , P Rajeev , Nalluveettil Santhosh J , A Jothiramalingam
Published: June 2024

With the present state of the art technology, size and mass of the satellites have come down. This necessitated the need for a low shock separation system that does not have mass attached to the separated satellite. Development of Nano satellites with mass of the order of 1 to 24 kg has become popular among scientific/ academic institutions for carrying out scientific experiments. INLS 3U Uni-Pod System (Nano satellite dispenser system) is a satellite dispensing system designed by ISRO for accommodating four 3U class Nano satellites in a single structure where each satellite is deployed independently by separate actuation commands. INLS stands for ISRO's Nano satellite Launch System. The INLS 3U Uni-Pod separation system successfully flown in ISRO’s Launch Vehicle mission for deployment of three satellites from abroad. CubeSat separation system consists of a structure housing the satellite, Holding and release mechanism (HDRM), rattling arresting mechanism, satellite ejection mechanism and movement arresting/ locking mechanism. The system was designed and developed for accommodating four satellites with a maximum mass of 6.0 kg, meeting the CubeSat Design Specification (CDS). Wire fusing system is used as HDRM. Helical compression spring with pusher plate is used for ejecting the satellite. Mechanism with double torsion spring is used for rattling arresting. The system was tested in ground conditions and in thermo-vacuum environment (-15°C & +60°C) nearly 40 times and found meeting the design specifications. The actuation time, separation time, electrical specifications, separation velocity and rates are designed at par with the internationally available commercial systems. The satellite ejection time is within one second from command. Confirmation of satellite separation is through micro switches and reed switches. The system can be mounted in two configurations, viz rail mounting and back mounting.
Fast Coupled Load Analysis through Reanalysis Technique: Formulation and Demonstration on Sample Problems
Authors: Kurudimath Kottresh , Jalan Salil Kanj , Rose Jancy
Published: June 2024

Design of Launch vehicle is multidisciplinary process in which designers of all the domain of engineering like mechanical, electronics, chemical, materials etc contribute. For the mechanical design, Coupled Load Analysis (CLA) is statutory requirement without which no launch vehicle will be allowed to fly.

In CLA, launch vehicle is subjected to various loads during its flight due to engine thrust depletion / shut-off, thrust oscillation, wind and gust, maneuvering loads. In aerospace industry a standard CLA is performed by generating the mathematical model of launch vehicle and coupling it with reduced mathematical model of payload and applying the boundary conditions. A CLA is a time consuming process as several flight instances and load cases need to be considered along with generation of structural dynamic model at each time instants. For every new mission, the payloads are mission specific whereas the launch vehicle and the loads remain unchanged. To take advantage of this fact, a new method called “Fast CLA through Reanalysis technique” is proposed in the present paper.

Fast Coupled Load analysis eliminates the need to generate new coupled mathematical model of launch vehicle and payload in case only payload is changed for the new mission. The method uses system frequencies of the original system (launch vehicle + original payload), eigen vectors row corresponding to the launch vehicle original payload interface, internal points of original payload and external load application location and mass and stiffness matrix of the original and new payload to determine responses for the new payload without performing traditional CLA. This can be performed outside the finite element software. At present, formulation of the analysis is completed and tested for lumped parameter model which gives encouraging results. Methodology is being implemented for the full launch Vehicle.
A Comparative Study of RANS and Machine Learning Techniques for Aerodynamic Analysis of Aerofoils
Authors: M N Lochan , N Rakshitha , Prasad B K Swathi , Sivasubramanian Jayahar
Published: June 2024

The design of aerospace applications necessities precise predictions of aerodynamic properties, often obtained through resource-intensive numerical simulations. These simulations, though they are accurate, but are unsuitable for iterative design processes due to their computational complexity and time-consuming nature. To address this challenge, machine learning, with its data-driven approach and advanced algorithms, offers a novel and cost-effective solution for predicting airfoil characteristics with exceptional precision and speed. This study explores the application of the Back-Propagation Neural Network (BPNN), a machine learning model, to forecast critical aerodynamic coefficients such as lift and drag for airfoils. The BPNN model is fed with input parameters including the airfoils name, flow Reynolds number, and angle of attack in relation to incoming flows. Training the BPNN model is accomplished using a dataset derived from CFD simulations employing the Spalart–Allmaras turbulence model on three distinct NACA series airfoils under varying aerodynamic conditions. The data from these simulations are divided into training (70%) and validation/testing (30%) subsets. The BPNN demonstrates a high level of accuracy in predicting these coefficients, evident through low root mean square error (RMSE) and a close alignment between predicted and actual values.
Comparative Analysis of Axial Flux and Radial Flux Motors for UAV Propulsion: Design and Suitability Assessment
Authors: C Carunaiselvane , Kumar Rajesh
Published: June 2024

In the architecture of an Unmanned Aerial Vehicle (UAV), a crucial component responsible for the propulsion system is the electric motor. Over the years, different types of electric motors, including Brushless Direct Current (BLDC), have supported the UAV’s propulsion system in diverse configurations. However, in the context of flux flow, the Radial Flux Permanent Magnet Motor (RFPMM) has been given more priority than the Axial Flux Permanent Magnet Motor (AFPMM) due to its sustainability in design and construction. Nevertheless, the AFPMM boasts higher speed, power density, lower weight, and greater efficiency than the RFPMM, because of its shorter flux path and the absence of end-turn winding. Therefore, this paper focuses to conduct a suitability analysis of an AFPMM as a shaft-connected propeller-mounted motor, with the intention of replacing the RFPMM in UAV applications. The design of the AFPMM, incorporating topologies featuring a one-rotor, one-stator configuration, is considered. In this research, the physical dimensions of an AFPMM required to meet performance parameters are derived using systematic analytical equations. Furthermore, the design is executed using a multi-physics simulation tool to analyse the electromagnetic behaviour of the model. To validate the designed model and compare its characteristics, a prototype of BLDC RFPMM with similar output performance parameters is selected. The operating parameters are tested for compliance with the recommended output characteristics of the Original Equipment Manufacturer (OEM). Through reverse engineering, the design dimensions are obtained, and the electromagnetic behaviour is analysed using a multi-physics simulation tool. Moreover, based on the performance characteristics of the RFPMM, the design dimensions of the AFPMM are determined using sizing equations and assumed design variables. The suitability analysis, focusing on UAV behaviour is scrutinized to identify the most appropriate electric motor for ensuring the sustainable and efficient operations.
Study of Crew Seat Impact Attenuation System for Indian Manned Space Mission
Authors: Avirah Nohin K , Lakshman Dasu Deva Karthik , Potnuru Sai Santhosh , Pramod Athul P , Kurian Sabin
Published: June 2024

The descent phase of Indian Manned Space Mission culminates with a crew module impacting at a predetermined site in Indian waters. During water impact, huge loads are experienced by astronauts. This demands an impact attenuation system which can attenuate the impact loads and reduce the acceleration experienced by astronauts to safe levels. Current state of the art impact attenuation systems uses honeycomb core, which is passive and can only be used once (at touchdown impact) during the entire mission. Active and reusable attenuation systems for crew modules are still an unexplored territory. Three configurations of impact attenuators are selected for this study for the crew module configuration, namely, hydraulic damper, hydro-pneumatic damper and airbag systems. All the subsystems are mathematically modelled, and initial sizes are estimated using Genetic Algorithm and SQP optimization techniques. Semi-active control for Hydraulic and Hydro-Pneumatic dampers are implemented and evaluated against its passive counterpart. An airbag impact attenuation system is studied and its performance in two configurations, stuck and unstuck are evaluated. Venting will not cease for the former configuration, whereas it is pressure controlled for the latter. For zero-degree impact load case, Brinkley DRI (Direct Response Index), a NASA HSIR index on the risk of likelihood of spinal damage, is reduced by 36% for hydraulic damper and 22% for Hydro-Pneumatic damper using semi-active control and 15% for Airbag system. Hydraulic dampers were proven to be superior to Airbag and Hydro-Pneumatic systems within the spatial constraints imposed by the present crew module configuration.
Fault Detection in Machine Bearings Using Deep Learning
Authors: Vaishnavi A. , Sharma Anju , Naidu VPS
Published: June 2024

In the contemporary industrial landscape, machinery stands as the cornerstone of various sectors. Over time, these machines undergo wear and tear due to extensive use, leading to the introduction of subtle faults into the machine readings. Recognizing the pivotal role of machinery in diverse industries, the timely detection of these faults becomes imperative. Early fault detection is crucial for preventing costly downtimes, ensuring operational efficiency, and enhancing overall safety. This paper addresses the need for an effective condition monitoring and fault detection system, focusing specifically on the application of the Long Short-Term Memory (LSTM) deep learning model for fault detection in bearings using accelerometer data. The preprocessing phase involves extracting time domain features, encompassing normal, differentiated, integrated, and carefully selected signals, to create an informative dataset tailored for the LSTM model. This model is then meticulously trained on the dataset to discern and accurately diagnose faults within the machinery. The research meticulously observes and reports that the LSTM model achieves an impressive 100% accuracy in fault detection, showcasing its robust capabilities in identifying subtle anomalies within the machine vibrations. In conclusion, the study underscores the critical importance of early fault detection in industrial machinery and highlights the efficacy of the LSTM model in this domain. The singular focus on the LSTM model demonstrates its proficiency in achieving accurate fault detection, contributing significantly to the predictive maintenance field. This research not only advances fault detection methodologies but also fosters a more reliable and sustainable industrial landscape, emphasizing the potential of deep learning techniques, particularly the LSTM model, in ensuring the optimal performance and longevity of machinery in diverse industrial settings.
Velocity Estimation of a Descending Spacecraft in Atmosphereless Environment Using Deep Learning
Authors: Avanashilingam Jayanth Balaji , Thokala Satish
Published: June 2024

Today’s space programs are ambitious and require increased level of onboard autonomy. Various sensing techniques and algorithms were developed over the years to achieve the same. However, vision-based sensing techniques have enabled higher level of autonomy in the navigation of space systems. The major advantage of vison-based sensing is its ability to offer high precision navigation. However, the traditional vision-based sensing techniques translate raw image into data which needs to be processed and can be used to control the spacecraft. The increasingly complex mission requirements motivate the use of vision-based techniques that use artificial intelligence with deep learning. Availability of sufficient onboard processing resources is a major challenge. Though space-based deployment of deep learning is in the experimental phase, but the space industry has already adopted AI on the ground systems.

Deep learning technique for spacecraft navigation in an unknown and unpredictable environment, like Lunar or Martian, is an area of research in space industry. Considering the distance from Earth, real-time ground control is impractical in such space missions. Velocity estimation of a descending spacecraft in Lunar environment is selected for the research work produced in this paper. Precisely estimating object's velocity is a vital component in the trajectory planning of space vehicles, such as landers, designed for descent onto Lunar or Martian terrains. In this paper, an effort is made to investigate the viability of velocity estimates by using images obtained from Lunar Reconnaissance Orbiter Cameras (LROC) that are part of a publicly available dataset released by Arizona State University (ASU) — the dataset contains minimal images. However, this imagery dataset is limited and not sufficient to train a deep learning model. Hence synthetic data is generated in this research. The study investigates usage of Condition-Generative Adversarial Networks(C-GAN) to generate synthetic data for image-based velocity estimates to support the proposed workflow. NVIDIA GPU is used to train the deep learning model. The forecast accuracy of the velocity of atmosphere-less objects is empirically examined, and the final results are reported.
Виробнича практика з медсестринства очима студентів 3 курсу медичного університету
Authors: Томашкевич Галина Іванівна
Published: June 2024

Не зважаючи на навчання в умовах повномасштабної війни, викладачі кафедри пропедевтики внутрішньої медицини, співробітники навчального відділу та керівництво Вінницького національного медичного університету ім. М.І. Пирогова намагаються поліпшити умови проведення виробничої практики з медсестринства, оволодіння студентами необхідними практичними навичками. Студенти мали вибір форми проходження виробничої практики. З метою удосконалення проведення виробничої практики проаналізована оцінка студентами організація виробничої практики з медсестринства, ступінь оволодіння практичними навичками за результатами анонімного анкетування. На думку 89,7% студентів, що працювали на базі кафедри пропедевтики внутрішньої медицини, розміщених матеріалів на сайті достатньо для оволодіння необхідними практичними навичками. Переважна кількість студентів (75,9%), що працювали у відділеннях із медичними центрами, мають аналогічну думку. Суттєвої різниці між кількістю практичних навичок, що викликають труднощі, ми не визначили. Переважна кількість студентів (96%) задоволена змістом та об’ємом покрокових інструкцій, створених співробітниками кафедри, та мали достатньо часу для ознайомлення з ними, використовували їх у симуляційному класі для відпрацювання виконання практичних навичок. Самооцінка виконання практичних навичок студентами відрізняється після складання диференційного заліку залежно від форми проходження виробничої практики. Самооцінка свідчить про усвідомлення студентами недоліків та переваг роботи без попереднього відпрацювання практичних навичок у симуляційному класі, але на наш погляд вона перевищена. Надзвичайно велике значення комунікативних відношень між викладачем та студентом, студентом та студентом, студентом та медичними працівниками, студентом та пацієнтом. Відсутність комунікації призводить до небажання та боязні виконання практичних навичок. Навчання студента медичного університету має бути спрямоване першочергово на визначення життєво необхідних показників для оцінки загального стану пацієнта, попереднього синдромального діагнозу з наступним складанням плану та виконанням діагностичних процедур, надання невідкладної долікарської допомоги.
PENGGEROMBOLAN KECAMATAN DI PROVINSI JAWA BARAT BERDASARKAN AKSES PENDIDIKAN MENENGAH ATAS (SMA-SEDERAJAT) DENGAN K-PROTOTYPES
Authors: Octaviana Sofia , Syauqi Ahmad , Fitrianto Anwar , Erfiani Erfiani , Pradana Alfa Nugraha
Published: June 2024

Education is an important element for the Indonesian nation and must be felt by all citizens. The availability of educational facilities is important for the realization of overall educational equality for the Indonesian people. The aim of this research is to group sub-districts in West Java Province according to their level of access to Senior High School (SHS-equivalent). The data included in this study comprises both numerical and categorical variables, which were obtained from the 2021 Village Potential Data Collection (PODES) conducted by the Central Statistics Agency. A cluster analysis method that can be used to group objects based on numerical and categorical data is K-Prototypes. The results of the grouping divide the data into 2 groups, where the first group has the characteristics of an urban subdistrict, the topographic area is plain, access to the nearest high school is very easy, and has an average number of high school and equivalent schools of 22 schools per subdistrict, and has an average distance to the nearest high school of 1,86 km. Meanwhile, the second group has the characteristics of subdistricts with rural areas, topography in the form of slopes, easy access to the nearest high school, and has an average number of high schools of 7 per subdistrict, and the average distance to the nearest high school is 4,06 km. The second group is sub-districts that need to be given special attention because they have relatively fewer high schools and the distance to the nearest high school is further