bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing the Volume of Delivered Enteral Feeds Using a Volume-Based Feeding Protocol in a Neuroscience Intensive Care Unit
Authors: Smith L. Douglas , Hoy Haley , Whitmore Sage
Published: June 2024

Background

Iatrogenic malnutrition is a significant burden to patients, clinicians, and health care systems. Compared with well-nourished patients, underfed patients (those who receive less than 80% of their daily energy requirement) have more adverse outcomes related to nutritional status. Volume-based protocols allow for catch-up titrations, are consistently superior to rate-based protocols, and can be implemented in most settings.

Local Problem

This project was conducted in an 8-bed neuroscience intensive care unit in which up to 41% of patients who required enteral feeding were underfed.

Methods

This quality improvement clinical practice change project used a before-and-after design to evaluate (1) the effect of implementing a volume-based feeding protocol on the delivery of enteral feeds and (2) the effect of a nutrition-based project on staff members’ attitudes regarding nutrition in critical care. The effectiveness of a volume-based feeding titration protocol was compared with that of a rate-based feeding protocol for achieving delivery of at least 80% of prescribed nutrition per 24-hour period. Staff members’ attitudes were assessed using a survey before and after the project.

Results

During 241 enteral feeding days (n = 40 patients), the percentage of delivered enteral feeding volume and the percentage of days patients received at least 80% of the prescribed volume increased after volume-based feeding was implemented. After project implementation, 74 staff members reported increased emphasis on nutrition delivery in their practice and a higher level of agreement that nutrition is a priority when caring for critically ill patients.

Conclusions

Using a volume-based feeding protocol with supplemental staff education resulted in improved delivery of prescribed enteral feeding.
An investigation on nurses’ competencies and practices regarding enteral tube medication administration: a cross-sectional study
Authors: Di Matteo Roberta , Gardalini Menada , Gatti Denise , Bolgeo Tatiana , Maconi Antonio
Published: June 2024

Background: understanding how healthcare professionals correctly administer medications through enteral routes is necessary to reduce patient morbidity and mortality. The study’s objective is to evaluate nurses’ competencies and management methods in administering oral medications to hospitalized patients who have enteral feeding tubes. Materials and Methods: an observational cross-sectional study involving nurses employed at the University Hospital for at least six months. A survey consisting of 16 questions related to medication dilution, pharmaceutical form management, and enteral medication administration techniques was administered. Results: a total of 218 nurses were recruited, with a mean age of 30.95 years (SD 6.15), of whom 132 (60.5%) were female, and 173 (78.9%) held a bachelor’s degree. Approximately half of the responses (49.3%) were incorrect. Conclusions: nurses should improve their knowledge regarding enteral medication administration. Nurses are responsible for pharmacological management, and their level of knowledge directly impacts the health and safety of these patients. Therefore, specific training addressing the identified gaps would be appropriate.
Chikitsanjana: A 17th century book of Ayurveda therapeutics
Authors: Vasava Ashvinee Nansingbhai , Vyas Hitesh A. , Baghel Arjun Singh , Singh Preetpal , Vasani Dharmik R. , Patil Sunny C.
Published: June 2024

Ayurvedic literature has been flowing steadily since the Vedic era. This also includes pretty little books, extending from 100 to 300 verses that described merely the diagnosis of diseases and treatment with simple but experienced remedies. To introduce and assess the text Chikitsanjana, authored by Vidyapati, for its originality and importance in Ayurvedic practice. The text Chikitsanjana has been published only twice. The first publication was published by Vaidyaka jnana prasaraka sabha, Mumbai in 1894. The second and presently available publication was published in the year 1979 by Sastu sahitya vardhaka karyalaya, Ahmedabad, Gujarat, which is considered to review in this attempt. The author, Vidyapati, is a relatively unknown name in Ayurveda literature, and he makes no attempt to introduce himself in the work. This text describes the treatment of total of 42 diseases. The author discusses treatments from all eight branches of Ayurveda but concentrates primarily on Kayachikitsa. The text has 267 stanzas. Out of 267 verses of the text, 24 verses are word-to-word similar to the verses of other popular texts of Ayurveda. Chikitsanjana mainly focuses on Yukti vyapashraya chikitsa (~ logic-based treatment). Almost all kinds of Kashaya kalpana (~dosage forms) are mentioned while describing the treatment of diseases. The most commonly used forms are Churna (~powder) and Kwatha (~decoction) for internal use and Lepa (~ointment or paste) for external use. The text Chikitsanjana which is in the form of a Samgraha text can be considered handbook or ready reference book for general practitioners of Ayurveda.
Single-Ended and Differentially Operated Microwave Microfluidic Sensors for Biomedical Applications
Authors: Shaterian Zahra
Published: June 2024

Background:

This research is focused on the design of highly sensitive microfluidic sensors for the applications in liquid dielectric characterizations including biomedical samples.

Methods:

Considering the narrow-band operation of microfluidic sensors based on microwave resonators, in this study, microfluidic sensors based on the variation of transmission phase in microwave transmission lines (TLs) are proposed. It is shown that among different microwave TLs, slot-lines are an appropriate type of TL for sensing applications because a major portion of the electromagnetic (EM) field passes above the line, where a microfluidic channel can be easily devised.

Results:

The proposed concept is presented and the functionality of the proposed sensor is validated through full-wave EM simulations. Moreover, the effects of the dimensions of the microfluidic channel and the thickness of the substrate on the sensitivity of the sensor are studied. Furthermore, taking the advantages of differential circuits and systems into account, a differential version of the microfluidic sensor is also presented. It is shown that the sensitivity of the sensor can be adjusted according to the application. Specifically speaking, the sensitivity of the proposed microfluidic sensor is almost linearly proportional to the length of the channel, i.e., the sensitivity can be doubled by doubling the channel length.

Conclusions:

In this research, it is shown that using slot-line TLs highly sensitive microfluidic sensors can be designed for the applications in liquid dielectric characterizations, especially for biomedical samples where small variations of permittivity have to be detected.
Repeatability of Choroidal Thickness Measurements in Healthy Subjects using RTVue XR Optical Coherence Tomography
Authors: Mansoori Tarannum , Charan Aknoor Sree Ram , Suresh Narala , Pesala Veerendranath , Nagalla Balakrishna
Published: June 2024

Purpose:

To determine the intrasession, intraobserver, interobserver, and repeatability of choroidal thickness measurements in the healthy subjects imaged on enhanced depth imaging system of RTVue XR spectral domain optical coherence tomography (OCT).

Methods:

In this prospective, cross-sectional study, seventy eyes of 70 healthy volunteers with no known ocular disease were imaged using high-density scanning protocol of RTVue XR OCT. In a single imaging session, three sequential 12 mm macular-enhanced depth horizontal line scans were obtained through the fovea. Two experienced examiners measured the subfoveal choroidal thickness (SFCT), choroidal thickness at 500 μm nasally and temporally from the fovea in all the eyes, using the manual calipers provided in the software. The graders were masked to each other's measurement readings. The coefficient of repeatability (CR) and intraclass correlation coefficient (ICC) were used to measure the reliability within graders. Intergrader variability was assessed using Bland-Altman method and 95% limits of agreement (LoA).

Results:

Intragrader CR for grader one was 4.11 μm (95% confidence interval [CI], −2.84–11.06) for SFCT and 5.73 μm (95% CI, −3.71–15.16) for the grader two. Intragrader ICC of grader one ranged from 0.996 for SFCT to 0.994 for temporal choroidal thickness. Intragrader ICC of grader two ranged from 0.993 for temporal choroidal thickness to 0.991 for SFCT. Intergrader CR ranged from 5.24 μm (95% CI, −4.66–15.15) for SFCT to 5.89 μm (95% CI, −7.27–19.04) for temporal choroidal thickness. Intergrader 95% LoA for SFCT, nasal and temporal choroidal thickness were, −15.84–12.15 μm, −15.99–17.7 μm, and − 19.12–15.57 μm, respectively.

Conclusion:

Choroidal thickness measurements can be quantified with good repeatability using RTVue XR OCT, which would be useful in patients with chorioretinal diseases.
Evaluation of Choroidal Vascularity Index in Keratoconus Patients: Does Choroidal Vascularity Change in Keratoconus?
Authors: Hashemian Mohammad Naser , Ghafarian Sadegh , Riazi-Esfahani Hamid , Khalili Pour Elias
Published: June 2024

Purpose:

To investigate the choroidal structure in keratoconic patients with different severity using the choroidal vascularity index (CVI) derived from image binarization on enhanced depth imaging optical coherence tomography scans (EDI-OCT).

Methods:

Sixty-eight eyes from 34 keratoconus (KCN) patients and 72 eyes from 36 healthy subjects were recruited in this prospective, noninterventional, comparative cross-sectional study. EDI-OCT was employed to measure choroidal parameters, including choroidal thickness (CT), total choroidal area (TCA), luminal area, stromal area, and CVI.

Results:

Subfoveal CT was 354.6 ± 66.8 mm in the control group and 371 ± 64.5 mm in the KCN group (P= 0.86). There was no significant difference between control and KCN groups in terms of TCA (0.66 ± 0.14 mm2vs. 0.7 ± 0.12 mm2;P= 0.70), luminal area (0.49 ± 0.10 mm2vs. 0.53 ± 0.08 mm2;P= 0.67), and stromal area (0.16 ± 0.05 mm2vs. 0.17 ± 0.05 mm2;P= 0.84). CVI was also comparable in the control group (75.4% ±3.4%) and the KCN group (75.6% ±4.5%;P= 0.43). There was also no significant correlation between other choroidal parameters and KCN severity indices.

Conclusion:

It seems that CVI as well as other choroidal biomarkers were not significantly different between patients with KCN and healthy subjects.
A Case of Persistent Hypoglycemia: Emphasizing the Role of Kidneys
Authors: Govindaraju Praveen , Khan Mohammed Fahad , Augustine Rohan , Ballal Hebri Sudarshan
Published: June 2024

Hypoglycemia is an important cause of morbidity and mortality in patients with diabetes mellitus. However, hypoglycemia in patients without diabetes warrants extensive clinical and biochemical evaluations. Traditionally, it occurs either in patients with underlying illness or is seemingly healthy. In patients with underlying comorbidities, hypoglycemia is usually straightforward and may be multifactorial in etiology. A particularly vulnerable population is patients with chronic kidney disease (CKD). We hereby describe a case of persistent hypoglycemia in a 73-year-old nondiabetic CKD presenting as a diagnostic enigma and the possible mechanisms behind it.
Prolonged Honeymoon Phase in Adult-Onset Type 1 Diabetes Mellitus: A Case Study
Authors: Shah Pranjali
Published: June 2024

Type 1 diabetes mellitus (T1DM) exhibits heterogeneity in presentation, and the “honeymoon” period, characterized by temporary beta-cell function restoration, is a significant aspect influencing disease progression. Adult-onset T1DM differs from pediatric cases, with complete insulin withdrawal being rare. This study investigates a 23-year-old female positive for glutamic acid decarboxylase (GAD) antibodies to assess the potential for an extended honeymoon phase. The patient, without significant medical history, presented with recurrent boils, notable weight loss, and had a family history of diabetes (maternal grandmother). Laboratory results showed uncontrolled hyperglycemia, absence of C-peptide, and positive for anti-GAD. Treatment involved CGMS fixation and insulin degludec/aspart, leading to excellent sugar control. Notably, insulin dosage reduction and improved C-peptide levels occurred over two years. This case highlights the complexity of T1DM presentations, the potential for extended honeymoon phases, and emphasizes the need for personalized management. Ongoing research into honeymoon phase determinants and genetic aspects will refine the understanding and optimize care for autoimmune diabetes.
The Impact of Insulin Degludec on Glucocorticoid-Induced Hyperglycemia in Patients with Diabetes and COVID-19 Infection
Authors: Prasanna Varun , Venketesan Ravindranath
Published: June 2024

Objective:

The objective was to assess the effectiveness and safety of insulin degludec (IDeg) on glycemic control in people with diabetes (PWD) hospitalized for moderate-to-severe coronavirus disease 2019 (COVID-19).

Design:

This study is a retrospective cohort study.

Setting and Participants:

Data were retrieved from medical records of PWD hospitalized for moderate-to-severe COVID-19. All patients who had steroid-induced hyperglycemia (SIH) were initiated with basal-bolus regimen with IDeg and human actaprid (HA) as part of their standard of care during admission. Data records at admission and discharge were retrieved and analyzed for hyperglycemia, insulin status, hypoglycemia, and other adverse events. The sigma plot version 15.0 was used to perform the statistical analysis and a P value (<0.05) was considered statistically significant.

Results:

The study retrieved data from medical records of 48 PWD hospitalized for moderate-to-severe COVID-19 and SIH for an average of 6.8 ± 2.5 days. There was a statistically significant decrease in average fasting plasma glucose from baseline (231.2 ± 91.1 mg/dL) to day 7/discharge (150.7 ± 32.1 mg/dL) (P < 0.05). The postprandial glucose showed a nonsignificant decrease; corresponding values were 295.0 ± 118.4 and 223.7 ± 65.4 mg/dL, respectively. The average IDeg dose increased significantly from baseline to day 7/discharge (15.6 ± 5.0 and 20.1 ± 6.5 units, respectively; P < 0.05). There was nonsignificant increase in average HA dose from 53.1 ± 16.7 IU on day 1 to 59.8 ± 16.6 IU on discharge day. No adverse events were reported in the medical records during hospitalization.

Conclusion:

IDeg is an effective and safe insulin for managing hyperglycemia in PWD who developed SIH during hospitalization for moderate-to-severe COVID-19.
Non-pharmacological Methods Used in the Management of Type 2 Diabetes Mellitus by a Selected Group of People with T2DM in Colombo District, Sri Lanka: A Mixed-Method Study
Authors: Herath Lakshani , Kamalsiri Manisha , Inthuja Perananthan , Gamage Gayani P , Vidanage Dinithi
Published: June 2024

Aims and Objectives:

Type 2 diabetes mellitus (T2DM) is one of the most common noncommunicable diseases, which causes high mortality and morbidity among adults. The prevalence of T2DM in Sri Lanka is high due to the unhealthy lifestyles of individuals. Both pharmacological and non-pharmacological interventions are practiced by people with T2DM to achieve better glycemic control. Managing T2DM with non-pharmacological methods is beneficial to both the patients and the country, as they are cost-effective and produce fewer complications. Thus, this study aimed to explore the practice of non-pharmacological methods and associated barriers to adherence in individuals with T2DM who attended the diabetic clinic at a tertiary care facility in Sri Lanka.

Materials and Methods:

A descriptive cross-sectional study was conducted with both qualitative and quantitative aspects among a conveniently selected 138 individuals with T2DM who attended the diabetic clinic at the University Hospital–Kotelawala Defence University (UH-KDU). Data were collected using an interviewer-administered questionnaire and one-to-one interviews. Gathered data were analyzed by using the SPSS 25.0 version and thematic analysis.

Results:

The mean age of the participants was 61 (± 10.2) years, and the mean duration of T2DM was 10.1 (±7.9) years. Diet control, exercise, stress management, and adding glucose-lowering food have been identified as the main non-pharmacological methods practiced. Adherence to family meal culture, resistance to follow dietary guidelines, aging, low income, and lack of time were reported by the participants as barriers to adherence. Although males spent more time on exercise compared to females (male vs. female; 36.1 vs. 15.3min, P = 0.025), both groups demonstrated poor glycemic levels (male vs. female; 141.3 ± 52 vs. 136.5 ± 42.2 mg/dl) and higher body mass index (male vs. female; 24.7 ± 4.7 vs. 25.8 ± 4.5 kg/m2).

Conclusion:

The non-pharmacological practices were not up to the standards of current recommendations for the management of T2DM. Hence, there is a need to improve the motivation of the participants to adapt to a healthy lifestyle.
Role of Yoga in Prehypertension and Hypertension
Authors: Kumar Anil , Keshavamurthy G , Singh Navreet , Singh Balwinder , Vaidya Rajesh , Roy Tanmoy , Singh S P , Gupta Ankush , Bajaj Nitin , Barwad Parag , Singh Ekambir
Published: June 2024

Background:

The high prevalence of hypertension in India necessitates both pharmacological and nonpharmacological measures to control it. Here, we report the findings of a study to investigate the effectiveness of yoga therapy in lowering blood pressure (BP) in prehypertensive and hypertensive individuals.

Methods:

This was a single center, nonrandomized controlled clinical trial, of 200 hypertensives and 100 prehypertensives patients. The control group received the prescribed antihypertensive and lifestyle modification while the yoga group was additionally taught simple yogic exercise by a trained yoga teacher. This training included intensive supervised phase 2-h training sessions in Ujjayi breathing, Bhastrika Pranayama and chanting of “Om” for 10 lessons, followed by self-performed yogic exercise at home for 1 h till the end of study at 1 year.

Results:

The systolic BP (SBP) in the hypertensive yoga group was significantly lower (t = 3.04,P< 0.01) than the control group at 6 months, but not so at 1 year (SBP t = 0.53,P> 0.05). In the prehypertensive participants, at 6 months (t = 5.85,P= 0.00), and 1 year (t = 6.385,P< 0.05) a significant difference was observed between SBP of the two groups However, no significant difference was observed between the diastolic BP among hypertensives or prehypertensives at 6 months and 1 year.

Conclusion:

Our present study indicates that yoga therapy is a viable adjunct to pharmacological intervention to reduce SBP in the management of hypertension and prehypertension and that yoga should be incorporated in the treatment regime of such patients, specifically for individuals who have prehypertension.
Hybrid Approach for Postclassical Blalock–Taussig Shunt Tetralogy
Authors: Agrawal Vishal , Garg Pankaj , Vyas Pooja , Hasit Joshi , Mishra Amit
Published: June 2024

In developing countries, we still come across occasional patients who have undergone classic Blalock–Taussig shunt (CBTS) previously. We present a case of 23-year-old female with tetralogy of Fallot who had undergone CBTS operation at the age of 1 year and is now presented for total correction. Takedown of CBTS during surgery has catastrophic complications during looping and ligation of shunt due to extensive collateralization. We, therefore, took a hybrid approach for the patient. The CBTS was first blocked with the balloon, followed by surgical intracardiac repair, and finally, by device closure of CBTS.
Large‐area stretchable oxide thin‐film transistor arrays with sandwiched molybdenum in serpentine structure
Authors: Na Jeho , Oh Himchan , Kim Sujung , Na Bock Soon , Choi Ji Hun , Oh Ji‐Young , Byun Chunwon , Park Chan Woo
Published: June 2024

Stretchable electronics are gaining attention with the development of skin‐compatible health monitoring sensors and robotics applications. However, existing stretchable electronics show a tradeoff between reliability and stretchability when constructing transistor arrays. We aim to construct highly stretchable thin‐film transistor (TFT) arrays with high reliability for large sensor backplanes. The fabricated structure comprises oxide TFTs and serpentine‐shaped molybdenum interconnects that are sandwiched between top and bottom polyimide layers, achieving robustness under repeated tensile strain. Different materials for polyimide etch masks (i.e., aluminum, silicon nitride, and indium tin oxide) are tested. Within an 83.7 mm × 61 mm area, TFT arrays with a resolution of 25 pixels per inch can be stretched up to 30% without considerable performance degradation. As our TFTs are fabricated using common materials from display manufacturing, our development and findings may substantially benefit stretchable electronic industries where high reliability is required for large‐area panels.
Study of Different Designs of Chevron for Effective Noise Reduction in Jet Engines
Authors: S Shri Hari , Rao Karthik M C
Published: June 2024

Due to their remarkable efficiency and efficacy, chevrons have emerged as a prominent subject of investigation within the Aviation Industry, primarily aimed at mitigating aircraft noise levels and achieving a quieter airborne experience. These chevrons function by inducing streamwise vortices into the shear layer, thereby augmenting the mixing process and resulting in a noteworthy reduction of low-frequency noise emissions. This paper aims to conduct a comparative computational analysis encompassing seven distinct chevron designs and one without chevrons. It also summarizes the previous works that led to the advancement of this technology. The size and configuration of the chevrons with the jet engine nacelle were designed to match the nozzle diameter of 100.48mm and 56.76mm, utilizing the advanced SolidWorks CAD modeling software. Subsequently, the computational analysis for each design was carried out using the SolidWorks Flow Simulation software. When it comes to civilian aircraft, it can be stated that the noise emitted in case of landing and take-off is comparatively high, so the parameters considered to solve the model were taken accordingly. The results were obtained in the form of acoustic power level contours and turbulent energy contours which unambiguously exhibit the effectiveness of each of the chevron designs that were taken into consideration for study. The acquired solutions were finally used for a comparative study among the designs. The results unequivocally demonstrated that the incorporation of chevrons consistently led to a reduction in sound pressure levels across all cases. Notably, the round-shaped chevron design exhibited superior performance compared to the other designs, boasting a substantial noise reduction of 2.85%.
Aero-Engine Fastened Structural Components: An Investigation into Impact Induced Three-Dimensional Dynamic Fracture Mechanism
Authors: Singh Shatrughan , Roy Mahapatra Debiprosad
Published: June 2024

Fastener joints play a critical role within aircraft engine structures by connecting vital structural members and withstanding various load scenarios, including impact occurrences like foreign object damage (FOD) on engine nacelles. The precise modeling and simulation of fastener joint behavior under dynamic loads are pivotal to ensuring their structural integrity and functionality. Simulation is essential for minimizing costly experiments in evaluating the challenging design aspect of containing FOD. Prior investigations on fastener joints have predominantly focused on quasi-static or in-plane dynamic loads. This study introduces a comprehensive methodology to simulate the impact dynamics of fastener joints, accommodating both in-plane and out-of-plane loads. The approach investigates the significance of rate-dependent and three-dimensional stress effects, including some comparative investigations using a simplified sequential stress update formulation available in LS-DYNA to understand the implication of coupled damage process leading to complex fracture mechanisms. Central to this investigation is capturing the intricate stress state and material behavior of fastener joints under high strain rates. The Johnson-Cook model is utilized to characterize viscoplastic deformation, incorporating damage evolution and crack initiation effects. A key challenge is determining parameters for this model, which is addressed through a consistent variational finite element formulation combined with coupon tests designed to encompass varying stress triaxiality ratios considering pure and mixed-mode loading conditions. By synergizing experimental data and simulation techniques, this methodology extracts parameters under dynamic tension, compression, and shear loading, providing precise predictions of fastener joint behavior. The study offers insights into stress distribution, deformation patterns, damage progression, and crack initiation mechanisms through simulations. In summary, this research enhances the understanding of fastener joint responses under dynamic loads and informs predictive failure analysis, facilitating design improvements for FOD mitigation and containment strategies.
Multi-Scale Modeling of Selective Laser Melting Process
Authors: Varma Aditya , Ganesh Kona Veera , Roy Mahapatra Debiprosad
Published: June 2024

The Selective Laser Melting (SLM) process is employed in high-precision layer-by-layer Additive Manufacturing (AM) on powder bed and aims to fabricate high-quality structural components. To gain a comprehensive understanding of the process and its optimization, both modeling and simulation in conjunction with extensive experimental studies along with laser calibration studies have been attempted. Multiscale and multi-physics-based simulations have the potential to bring out a new level of insight into the complex interaction of laser melting, solidification, and defect formation in the SLM parts. SLM process encompasses various physical phenomena during the formation of metal parts, starting with laser beam incidence and heat generation, heat transfer, melt/fluid flow, phase transition, and microstructure solidification. To effectively model this Multiphysics problem, it is imperative to consider different scales and compatible boundary conditions in the simulations. In this paper, we employ a numerical model for the SLM process, leveraging multi-scale and multi-physics simulation strategies. The model will describe the transition from powder to melt and melt to microstructure solid by applying the appropriate boundary conditions at each stage in the transition process. The model also accounts for temperature-dependent material properties of Ti-6Al-4V alloy, including specific heat capacity, thermal conductivity, viscosity, etc. These effective properties are evaluated under both room temperature and elevated temperature conditions through Molecular Dynamics (MD) simulations. The basic behaviour of melting-related property variation is to be studied and the effect on the melt pool characteristics is simulated. The ultimate aim of the scheme is to plug in temperature-dependent material properties in the model and predict the temporal distribution in the melt pool. The simulation results provide a detailed explanation of the SLM process in all three phases (powder, melt, and microstructure solid).
Selective Laser Melting Based Additive Manufacturing Process Diagnostics Using In-Line Monitoring Technique and Laser-Material Interaction Model
Authors: Raju Benjamin , Kancherla Kishore Babu , B S Dakshayini , Roy Mahapatra Debiprosad
Published: June 2024

Selective Laser Melting (SLM) has gained widespread usage in aviation, aerospace, and die manufacturing due to its exceptional capacity for producing intricate metal components of highly complex geometries. Nevertheless, the instability inherent in the SLM process frequently results in irregularities in the quality of the fabricated components. As a result, this hinders the continuous progress and broader acceptance of SLM technology. Addressing these challenges, in-process quality control strategies during SLM operations have emerged as effective remedies for mitigating the quality inconsistencies found in the final components. This study focuses on utilizing optical emission spectroscopy and IR thermography to continuously monitor and analyze the SLM process within the powder bed, intending to strengthen process control and minimize defects. Optical emission spectroscopy is employed to study the real-time interactions between the laser and powder bed, melt pool dynamics, material behavior, and energy deposition. In parallel, IR thermography provides temperature gradient mapping and thermal insights during SLM, facilitating the detection of potential thermal irregularities. By employing these diagnostic methods, deviations from anticipated process behavior are identified and classified, which can be employed in multi-physics models as input for studying defects and deformation. Real-time data acquisition enables swift detection of anomalies like powder segregation, uneven layer melting, and potential thermal concerns. The insights derived from optical emission spectroscopy and IR thermography are processed and analyzed. This study provides comprehensive process insights through optical spectroscopy and IR thermography. These advanced diagnostics not only elevate the overall quality of manufactured components but also cut down on post-processing and material wastage, rendering additive manufacturing more efficient and dependable.
A Methodology for Accelerated Thermo-Mechanical Fatigue Life Evaluation of Advanced Composites
Authors: Kancherla Kishore Babu , B S Dakshayini , Raju Benjamin , Roy Mahapatra Debiprosad
Published: June 2024

Thermo-mechanical fatigue and natural aging due to environmental conditions are challenging to simulate in an actual test with advanced fiber-reinforced composites, where their fatigue and aging behavior are little understood. Predictive modeling of these processes is challenging. Thermal cyclic tests take a prohibitively long time, although the strain rate effect can be scaled well for accelerating the mechanical stress cycles. Glass fabric composites have important applications in pipes, aircraft, and spacecraft structures, including microwave transparent structures, impact-resistant parts of the wing, fuselage deck and many other load-bearing structures. Often additional additively manufactured features and coatings on glass fabric composites are employed for thermal and anti-corrosion insulations. In this paper, we employ a thermo-mechanical fatigue model based on an accelerated fatigue test and life prediction under hot-to-cold cycles. Thermo-mechanical strain-controlled stress evolution is modeled and tested for fitting fatigue model parameters over thermal cycles under different creep stresses. The model accounts for damage mechanics-based treatment of stiffness degradation up to a limiting inelastic strain up to endurance limit stress, and strength degradation in the process of damage to crack initiation. The strain evolution and stiffness degradation are monitored, and fatigue strength degradation behavior is predicted using the constitutive model. A scheme for remaining user life (RUL) prediction is developed and the scheme is validated using different thermo-mechanical cycles as compared to the data used for fitting the constitutive model parameters. This study limits the fatigue damage to crack initiation in simple flexure and temperature cycles for specific micro-damage coalescence to interlaminar fracture. To generalize the life prediction methodology, a scheme based on finite element stress analysis-based progressive damage methodology is employed, which can be employed for complex composite structures involving different complex damage mechanisms and final failure modes.
Analytical and Experimental Evaluation of Seal Drag Force for Different Fluids
Authors: Yarolkar Makrand , Telore Milind , Patil Sandip
Published: June 2024

The present study discusses the determination of the Seal drag force in the application where an elastomeric seal is used with a metallic interface in the presence of different fluids. An analytical model was constructed to predict the seal drag force and an experimental test was performed to check the fidelity of the analytical model. A Design of Experiment (DoE) was utilized to perform an experimental test considering different factors affecting the Seal drag force. Statistical tools such as the Test for Equal Variances and One Way Analysis of Variance (ANOVA) were used to draw inferences for the population based on samples tested in the DoE test. It was observed that Glycol fluids lead to lubricant wash-off resulting in increased seal drag force. Additionally, non-lubricated seals tend to show higher seal drag force as compared to lubricated seals.
The Effect of Excessive Thermo-Mechanical Stress on the Performance of High-Pressure Hose Assemblies Used under Flexing Motion
Authors: Neve Abhilash , Patil Sandip
Published: June 2024

A lightweight high-pressure hose assembly consists of hose made with fabric braids and PTFE (Polytetrafluoroethylene) tube crimped with metallic fittings. These hose assemblies are mainly used for aircraft landing gear application considering its high-pressure sustenance and better flexibility.

The proposed study investigates the effect of thermo-mechanical stresses generated during cyclic soaking and flexibility testing at thermostatic subzero (-65°F) and high temperature (+275°F) on performance of high pressure- fabric braided hose assembly.

This effect was further studied through hose tear-down to investigate the hose layer degradation and focused changes in inner PTFE tube. With an incremental exposure to cyclic temperature environment, a linear growth was observed for the micropores within PTFE.
FE Modelling and Experimental Evaluation for the Surface Integrity of Thin-Walled Aluminum Alloy
Authors: Yarolkar Makrand , Harish Uppu , Patil Sandip , Patil Manasi
Published: June 2024

The present study discusses the effect of installation torque on the surface and subsurface deformations for thin-walled 7075 aluminum alloy adapters used in Aerospace applications. An FE model was constructed to predict the effect of torque-induced stresses on thin-walled geometry validated with experimentation. A detailed surface analysis was performed on 7075 aluminum to check superficial discontinuities, residual stresses, and grain deformations. The localized strain hardening resulting from increased dislocation density and its effect on surface microhardness was further studied using SEM (Scanning Electron Microscope). The predicted surface level plastic strain of .25%, on the castle nut adapter, was further validated with grain deformations measured using optical and scanning electron microscopy.
BIST Based Method for SEE Testing of Vikram1601 Processor
Authors: Joseph Dominic George , Daniel Joji , K Padmakumar , L Jayalekshmy , Devi Athula
Published: June 2024

A novel method for Single Event Effect (SEE) Radiation Testing using Built-In Self-Test (BIST) feature of indigenously developed Vikram1601 processor is discussed. Using BIST avoids need of exhaustive test vectors to ensure test coverage of all internal registers and a physical memory to store test vectors. Thus, processor is the only element vulnerable to radiation damage during testing. In the first part, a brief introduction, need and methods of radiation testing of electronics especially SEE of radiation on Silicon based devices, different radiation effects, radiation damage mechanisms and testing methods are described. A brief introduction to Vikram1601 processor, the instruction – TST, used as BIST and testing scheme implementation using TST for studying the SEE is explained. Radiation test facilities are explained with respect to the types of testing possible, capabilities, radiation particle species and maximum energies possible, size limitations of Silicon under test and System under test, duration of test for each species and energy etc. In the second part, the implementation of the testing scheme using an FPGA based system as checkout for online monitoring of the Vikram1601 Processor (mounted on a PCB along with necessary circuitry for operation) during irradiation and lab level validation (without irradiation) of the checkout, harness design etc. are detailed. The actual SEE radiation testing conducted at Inter University Accelerator Centre (IUAC) with all the set-up requirements, procedure and results are detailed subsequently. Testing with Nickel beam (33 MeV LET) caused 5 SEUs (Single Event Upsets) while testing with Gold beam (64 MeV LET) caused 15 SEUs.
Single Board Computer Based Data Acquisition System for Monitoring Parameters of Reusable Launch Vehicle Interface System
Authors: C Manu , Vinay Kumar Eagam , Gurusivanjaneya Abbireddy , V Vivekanand
Published: June 2024

With the upcoming technology demonstration projects such as the Reusable Launch Vehicle, easily portable data acquisition systems for ground testing are the need of the hour. The existing data acquisition systems used in ISRO are generally larger and of higher capability based on the number parameters to be acquired, which makes them underutilized in this case. To avoid this problem, a data acquisition system based on BeagleBone® Black, a Single Board Computer (SBC) is conceived. With this approach the number of components utilized would be reduced as we make use of ADCs present in the BeagleBone computer. Also, the size of the hardware setup is significantly reduced as the chosen SBC is small, making the developed Data Acquisition system portable. It could be moved anywhere with ease, even to the runway, where the final phase of ground testing happens.
A CDMA Based Approach for QoS Improvement in Intra-Aircraft Wireless Sensor Networks (IAWSN)
Authors: C S Adishesha , Ramamurthy Prasanna , Banerjee Kumardeb , Barik Mridul Sankar
Published: June 2024

Aviation industry is striving to leverage the technological advancements in connectivity, computation and data analytics. Scalable and robust connectivity enables futuristic applications like smart cabins, prognostic health management (PHM) and AI/ML based analytics for effective decision making leading to flight operational efficiency, optimized maintenance planning and aircraft downtime reduction. Wireless Sensor Networks (WSN) are gaining prominence on the aircraft for providing large scale connectivity solution that are essential for implementing various health monitoring applications like Structural Health Monitoring (SHM), Prognostic Health Management (PHM), etc. and control applications like smart lighting, smart seats, smart lavatory, etc. These applications help in improving passenger experience, flight operational efficiency, optimized maintenance planning and aircraft downtime reduction. Intra Aircraft WSNs (IAWSN) used for such applications are expected to provide robust and reliable communication performance. However, IAWSNs, when deployed, must co-exist with other wireless devices and networks based on Wi-Fi and Bluetooth technologies. Sharing of the ISM frequency band (2.4 GHz) among these networks makes the co-existence problem more challenging and has a significant impact on the Quality of Service (QoS) in terms of throughput, latency and Packet Error Rate (PER) of IAWSN. In addition, they are subjected to additional electromagnetic interference from other electronic and avionic systems onboard aircraft. There are various channel management, priority-based scheduling and time-sharing techniques that are deployed currently to address the co-existence problem. However, these methods perform a trade-off among one or more operational parameters like channel bandwidth, number of nodes per channel, throughput, latency, PER, etc. of IAWSN. Code Division Multiple Access (CDMA) technique is a proven one in cellular networks for providing reliable interference free communication performance especially in large scale networks. This paper evaluates the feasibility of deploying CDMA for IEEE 802.15.4 based IAWSN onboard aircraft. A CDMA based communication schema is proposed and simulated for IAWSN operating as per IEEE 802.15.4 protocol. The communication performance of the CDMA based IAWSN is evaluated in comparison with the performance of a standard IEEE 802.15.4 protocol implementation in the presence of interference from the co-nodes of the IAWSN and Wi-Fi devices by analyzing the QoS parameters like signal to noise ratio (SNR), operational bandwidth, Bit-Error Rate (BER) and Process Gain through simulation. Simulations results are evaluated against the desired performance level for a reference use case application. Improvement opportunities are identified and areas for future research are proposed.
Aircraft Weather Data Representation and Threat Management for Connected Weather Applications
Authors: Ramamurthy Prasanna , Gangadhar Balraj , Thulasidass Sathiyaseelan
Published: June 2024

Aviation industry has been continuously striving for reducing the number of flight crew in the aircraft cockpit for balancing operational efficiency with the flight economics. Concepts like Reduced Crew Operations (RCO) and Single Pilot Operations (SPO) are being experimented in this direction. In RCO and SPO, additional aid/system is needed for reducing the pilot’s workload and to help him/her in taking right decisions. Weather situational awareness and management of weather-related threats are significant part of the workload the pilot is subjected during the flight. Weather information presented to the pilot in the cockpit is obtained either from an onboard weather radar on larger commercial aircrafts or from other sources like Air Traffic Control, ADS-B Flight Information Services, Connected weather services, etc. Connected weather services are under development to provide accurate and reliable real time weather information to the aircrafts especially to the ones without an onboard weather radar. However, the cost of sharing the weather information through Airborne datalinks is directly related to the size of the weather data. The usefulness of weather data relies on the flight crew’s ability to interpret the weather data manually and take appropriate flight decision to avoid hazardous weather zones. But, in RCO and SPO, the Pilot is subjected to high workload by having to interpret multiple data presented in the cockpit apart from weather data and take multiple simultaneous actions. This paper proposes a novel method for representation of the weather data with minimal data size for storing and sharing it through connected weather services at reduced cost. It also proposes an automated weather threat assessment and advisory system based on this weather data. The proposed concepts are validated through simulation and the results are presented. The feasibility and challenges associated with the implementation of the proposed concept is discussed. Areas for future research are identified for maturing and implementing the technology.
On the Aero-Thermo-Structural Performance of Rectangular and Axisymmetric Scramjet Configurations
Authors: Nagarajan Kirupakaran Gopinath , K V Govindarajan , Roy Mahapatra Debiprosad
Published: June 2024

Scramjet-based hypersonic airbreathers are needed for next-generation defense and space applications. Two scramjet configurations, namely, rectangular and axisymmetric, are primarily studied in the literature. However, there is no quantitative comparison of the performance metrics between these two scramjet configurations. This study investigates the aero-thermo-structural performance of rectangular and axisymmetric scramjet engines at Mach 7 and 25 km altitude. A numerical framework involving computational fluid dynamics and computational structural dynamics is established. The aero-thermo-structural loads on the scramjet flow path are estimated using RANS/FANS simulation. A finite element-based coupled thermo-structural analysis is performed to understand the thermo-structural response. Before using the numerical models for the study, CFD and CSD modules are validated with literature data. The presence of oblique shocks in rectangular scramjets provides better compression than conical shocks in axisymmetric scramjets. Thus, the rectangular scramjet shows improved aerodynamic efficiency from a high lift-to-drag ratio. However, rectangular scramjet suffers from a high convective heat transfer rate due to high compression and shows large thermo-structural deformation and stress. Axisymmetric scramjet performs better mass capture than rectangular scramjet, influencing the propulsive efficiency. The large surface area available in axisymmetric scramjet allows for improved heat dissipation. Both scramjet configurations have associated advantages and disadvantages that are quantified through the aero-thermo-structural performance metrics. A unified scramjet configuration can combine rectangular and axisymmetric scramjets, such as Rectangular-to-Axisymmetric Shape Transition or REST scramjet.
Experimental Analysis of Force Recovery and Response Time Using Strain Measurement Sensors in Stress Wave Force Balance
Authors: Kamal Abhishek , Deka Sushmita , Sahoo Niranjan , Kulkarni Vinayak
Published: June 2024

Severe problem of aerodynamic heating and drag force are inherent with any hypersonic space vehicle like space shuttle, missiles etc. For proper design of vehicle, the drag force measurement become very crucial. Ground based test facilities are employed for these estimates along with any suitable force balance as well as sensors. There are many sensors (Accelerometer, Strain gauge and Piezofilm) reported in the literature that is used for evaluating the actual aerodynamic forces over test model in high speed flow. As per previous study, the piezofilm also become an alternative sensor over the strain gauges due to its simple instrumentation. For current investigation, the piezofilm and strain gauge sensors have mounted on same stress force balance to evaluate the response time as well as accuracy of predicted force at the same instant. However, these force balance need to be calibrated for inverse prediction of the force from recorded responses. A reliable multi point calibration methodology has been used to recover the calibration force. Initially, a blunt bicone shaped scaled “DASA CTV” model has been fabricated in house along with three component stress wave balance. Further, a multi-point calibration experiment has been performed over a test model at nine different locations. In literature, there is no any evidence has been found that effect of various sensors during calibration or actual shock tunnel experiments on a recovered forces. Hence, a calibration experimental studies focus on various sensors mounted on stress wave force balance to understand its behavior and also recovery of calibration forces during the experiment.