bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental performance of patient rooms using an integrated approach considering operational energy, daylight and comfort analysis
Authors: Eisazadeh Nazanin , De Troyer Frank , Allacker Karen
Published: February 2024

Purpose

The aim is to holistically assess the environmental performance of windows and analyse how their design and characteristics contribute to the overall performance of the building/space. This study focuses on the performance of windows in patient rooms hosting less mobile people.

Design/methodology/approach

This study investigates the life cycle environmental impacts of different glazing types, window frames and fire safety doors at the product level. This article also presents a building-integrated environmental analysis of patient rooms that considers the multiple functionalities of windows by incorporating dynamic energy analysis, comfort and daylighting performance with a life cycle assessment (LCA) study.

Findings

The results indicate that the amount of flat glass is the main contributor to the environmental impacts of the glazing units. As for the patient rooms, global warming shows the most significant contribution to the environmental costs, followed by human toxicity, particulate matter formation and eutrophication. The key drivers for these impacts are production processes and operational energy use. This study highlights the significance of evaluating a wide range of criteria for assessing the performance of windows.

Originality/value

An integrated assessment approach is used to investigate the influence of windows on environmental performance by considering the link between window/design parameters and their effects on energy use/costs, daylighting, comfort and environmental impacts. The embodied impacts of different building elements and the influence of various design parameters on environmental performance are assessed and compared. The environmental costs are expressed as an external environmental cost (euro).
Marine protected areas can benefit biodiversity even when bycatch species only partially overlap fisheries
Authors: Erm Philip , Balmford Andrew , Krueck Nils C. , Takashina Nao , Holden Matthew H.
Published: February 2024

Marine protected areas (MPAs) are increasingly relied upon to preserve biodiversity and ensure fisheries sustainability. Although recent analyses have shown that MPAs can provide overall biodiversity benefits even when they only redistribute fishing effort, these did not account for refuges outside of fishing grounds for non‐target species. It has been argued that such refuges could render MPAs obsolete where their chief benefit is to ensure species persistence.

Here, we modelled the outcomes associated with placing MPAs within a seascape where non‐target species' ranges can extend beyond fishing grounds.

In scenarios with no explicit fishing‐induced habitat damage, we found that MPAs provided a net biodiversity benefit so long as there was at least an approximately 60% overlap between fishing grounds and non‐target species' ranges. In scenarios with explicit fishing‐induced habitat damage for non‐target species, we found that MPAs instead benefitted biodiversity at all overlaps, but that this was reduced if target species' abundances also declined with damage.

Additionally, we identified counterintuitive mechanisms by which MPAs could either help or harm the same species depending on their location by changing fishing effort distribution patterns. However, MPAs did always increase the total fishing effort required to reach a catch target.

Policy implications: Our results showed that MPAs could still deliver biodiversity benefits in otherwise well‐regulated fisheries when species' ranges and fishing grounds did not fully overlap, and particularly when sensitive species and habitats were present. Well‐placed MPAs should thus be considered in such settings. However, MPAs were also less likely to be useful when range overlaps were low and always resulted in higher fishing effort to maintain the same catches.
DNA barcoding, an effective approach for the identification of thrips (Thysanoptera: Thripidae) in citrus orchards
Authors: Sánchez‐Luna Adriana , Johansen‐Naime Roberto M. , González‐Hernández Héctor , Guzmán‐Franco Ariel W.
Published: February 2024

Thrips are serious crop pests with a worldwide distribution. The first step in the design of control methods is accurate species identification. However, the morphological identification of thrips can be complex, especially as there is morphological variation amongst individuals of the same species. Analyzing a fragment of cytochrome c oxidase subunit I (COI) has been used successfully in the identification of insects and other arthropods. Citrus is among the most important crops in the world, and Mexico is one of the largest producers. Despite this, formal reports on the species diversity of thrips found in Mexican citrus orchards are scarce. We explored the species diversity of thrips in selected citrus orchards (of Mexican orange, Key lime and Persian lime), based on morphological taxonomy and on partial sequences of COI. We analyzed 111 thrips specimens, distributed in two genera: Frankliniella, including Frankliniella insularis, Frankliniella invasor and Frankliniella occidentalis; and Scirtothrips, including Scirtothrips citri and Scirtothrips dorsalis. Frankliniella insularis and F. invasor were the most abundant species in Mexican orange (Citrus × sinensis) and Persian lime (Citrus × latofolia) orchards. Scirtothrips dorsalis was the most abundant species in Key lime orchards (Citrus × aurantiifolia). Analysis of molecular variance (AMOVA) and haplotype analyses performed on F. insularis sequences (the most abundant species) showed no significant effect of geographical origin or plant host on its genetic population structure. DNA barcoding is a valuable method to complement the morphological identification of thrips in citrus orchards, allowing more accurate identification to species level.
Development of feed material and its effect on the nutritional composition of Protaetia brevitarsis larvae
Authors: EOM Hyeongjin , KIM Hunsung , HAHN Dongyup , KWON Ohseok
Published: February 2024

This study was carried out to assess the nutritional composition of Protaetia brevitarsis larvae (Pbl) reared on different feed materials. Four different types of feed materials were used to rear Pbl prior to nutritional analysis. The results show that the new formulation of feed material enhanced the crude fat content of Pbl by 75%, compared with the control. A marked increase in unsaturated fatty acids such as linoleic acid and oleic acid, by 100% compared with the control, in Pbl reared on the new formulation of feed material was also observed.
Hybrid immunity to SARS‐CoV‐2 in patients with chronic lymphocytic leukemia
Authors: Mellinghoff Sibylle C. , Robrecht Sandra , Sprute Rosanne , Mayer Leonie , Weskamm Leonie M. , Dahlke Christine , Gruell Henning , Teipel Finn , Schlößer Hans A. , Siepmann Klara , Thelen Martin , Fink Anna‐Maria , Fischer Kirsten , Klein Florian , Addo Marylyn M. , Kolovou Androniki , Cornely Oliver A. , Eichhorst Barbara , Hallek Michael , Langerbeins Petra
Published: February 2024

Objective

Preventing severe COVID‐19 remains a priority globally, particularly in the immunocompromised population. As shown in healthy individuals, immunity against SARS‐CoV‐2 can be yielded by previous infection, vaccination, or both (hybrid immunity). The objective of this observation study was to investigate hybrid immunity in patients with chronic lymphocytic leukemia (CLL).

Methods/Results

Blood samples of six patients with CLL were collected 55 days after fourth COVID‐19 vaccination. All patients had a SARS‐CoV‐2 infection within 12 months before the second booster (fourth vaccination). SARS‐CoV‐2 spike receptor binding domain (RBD)‐specific IgG antibodies were detectable in 6/6 (100.0%) CLL patients after four compared to 4/6 (66.7%) after three vaccinations. The median number of SARS‐CoV‐2 spike‐specific T cells after repeated booster vaccination plus infection was 166 spot‐forming cells (SFC) per million peripheral blood mononuclear cells. Overall, 5/5 (100%) studied patients showed a detectable increase in T cell activity.

Conclusion

Our data reveal an increase of cellular and humoral immune response in CLL patients after fourth COVID‐19 vaccination combined with SARS‐CoV‐2 infection, even in those undergoing B cell‐depleting treatment. Patients with prior vaccination failure now show a specific IgG response. Future research should explore the duration and effectiveness of hybrid immunity considering various factors like past infection and vaccination rates, types and numbers of doses, and emerging variants.
Angiotensin 1–7 increases cardiac tolerance to ischemia/reperfusion and mitigates adverse remodeling of the heart—The signaling mechanism
Authors: Derkachev Ivan A. , Popov Sergey V. , Maslov Leonid N. , Mukhomedzyanov Alexandr V. , Naryzhnaya Natalia V. , Gorbunov Alexander S. , Kan Artur , Krylatov Andrey V. , Podoksenov Yuri K. , Stepanov Ivan V. , Gusakova Svetlana V. , Fu Feng , Pei Jian‐Ming
Published: February 2024

Background

The high mortality rate of patients with acute myocardial infarction (AMI) remains the most pressing issue of modern cardiology. Over the past 10 years, there has been no significant reduction in mortality among patients with AMI. It is quite obvious that there is an urgent need to develop fundamentally new drugs for the treatment of AMI. Angiotensin 1–7 has some promise in this regard.

Objective

The objective of this article is analysis of published data on the cardioprotective properties of angiotensin 1–7.

Methods

PubMed, Scopus, Science Direct, and Google Scholar were used to search articles for this study.

Results

Angiotensin 1–7 increases cardiac tolerance to ischemia/reperfusion and mitigates adverse remodeling of the heart. Angiotensin 1–7 can prevent not only ischemic but also reperfusion cardiac injury. The activation of the Mas receptor plays a key role in these effects of angiotensin 1–7. Angiotensin 1–7 alleviates Ca2+ overload of cardiomyocytes and reactive oxygen species production in ischemia/reperfusion (I/R) of the myocardium. It is possible that both effects are involved in angiotensin 1–7‐triggered cardiac tolerance to I/R. Furthermore, angiotensin 1–7 inhibits apoptosis of cardiomyocytes and stimulates autophagy of cells. There is also indirect evidence suggesting that angiotensin 1–7 inhibits ferroptosis in cardiomyocytes. Moreover, angiotensin 1–7 possesses anti‐inflammatory properties, possibly achieved through NF‐kB activity inhibition. Phosphoinositide 3‐kinase, Akt, and NO synthase are involved in the infarct‐reducing effect of angiotensin 1–7. However, the specific end‐effector of the cardioprotective impact of angiotensin 1–7 remains unknown.

Conclusion

The molecular nature of the end‐effector of the infarct‐limiting effect of angiotensin 1–7 has not been elucidated. Perhaps, this end‐effector is the sarcolemmal KATP channel or the mitochondrial KATP channel.
The role of connectivity in conservation planning for species with obligatory interactions: Prospects for future climate scenarios
Authors: da Silva Janine P. , Hermoso Virgilio , Lopes‐Lima Manuel , Miranda Rafael , Filipe Ana Filipa , Sousa Ronaldo
Published: February 2024

Climate change may lead to range shifts, and barriers to such displacements may result in extirpations from previously suitable habitats. This may be particularly important in freshwater ecosystems that are highly fragmented by anthropogenic obstacles, such as dams and other smaller in‐stream barriers. Conservation planning in freshwaters should consider the dynamic effects of climate change and the ability of species to cope with it. In this study, we developed a framework for incorporating climate‐driven dispersal barriers into conservation planning taking into account the medium and long‐term impacts of climate change and species with obligatory interactions. Given that freshwater mussels (Bivalvia: Unionida) are a group of highly threatened organisms dependent on fish hosts to complete their larval development and dispersal, we used Marxan to prioritize areas for their joint conservation in the Iberian Peninsula as a case study. We tested two connectivity scenarios between current and future habitats, (i) unlimited dispersal capacity and (ii) dispersal constrained by artificial barriers, and also identified priority translocation areas for species that were unable to disperse. Accounting for the effects of climate change on species distributions allowed the identification of long‐term conservation areas, but disregarding artificial barriers to dispersal may lead to unrealistic solutions. Integrating the location of barriers allowed the identification of priority areas that are more likely to be colonized in the future following climatic shifts, although this resulted in an additional loss of six to eight features (~5%–7%) compared to solutions without dispersal constraints. Between 173 and 357 artificial barriers (~1.6%–3.3%) will potentially block species dispersal to irreplaceable planning units. Where removal of artificial barriers is unfeasible, conservation translocations may additionally cover up to eight additional features that do not meet conservation targets due to dispersal constraints. This study highlights the challenge of identifying protected areas to safeguard biodiversity under climate change.
Examining learning opportunities and perceptions of Latin American ESL learners in varying proficiency‐level groups
Authors: Spinelli Franciele
Published: February 2024

Learner‐to‐learner (peer) interaction has been integral to the second language (L2) classroom since the advent of communicative‐oriented pedagogies. Despite the well‐documented benefits of peer interaction, the extent to which learners benefit may be impacted by a range of factors, particularly their peers’ proficiency levels. Yet studies on the influence of peers’ proficiency have shown contradictory findings and are extensively focused on pairs rather than small groups. Furthermore, although low‐proficiency (LP) learners experience greater impacts from interaction with peers of different proficiency levels, their interactional patterns and perspectives are underexplored. This study investigates how six Latin American learners of English (core learners) co‐created learning opportunities as they interacted with non‐core learners (n = 33) in three proficiency small‐group interactions. A total of 18 group interactions were analysed for language‐related episodes (LREs) and turn‐takings. The results showed that core learners’ (CLs) LREs and turns diminished as their peers’ proficiency increased. However, fewer incorrect LRE resolutions were found when CLs were grouped with high‐proficiency (HP) peers. The CLs also perceived the interaction with HP peers as challenging but important for their L2 development. Additionally, aside from the proficiency level, CLs acknowledged the importance of their peers’ positive attitudes for the success of their interactions. These findings provide important insights into employing mixed‐proficiency groups to create more optimal learning conditions, particularly for LP learners.
Smartphones and attitudes to intimate partner violence: Evidence from Africa
Authors: Gillanders Robert , McNamara Glenn
Published: February 2024

This paper, using data from the Afrobarometer surveys, examines the potential for smartphones to influence attitudes to intimate partner violence (IPV). Controlling for ownership of television and radio, we find that those living in areas with a higher incidence of smartphone ownership are more likely to state that it is never justifiable for a man to beat his wife. This is the case for both male and female respondents. We find that the strength of the association between regional smartphone proliferation and attitudes to IPV is similar for those who frequently get news from social media and those who get news from elsewhere. This suggests that our results are not driven entirely by personal social media use. Finally, we only find a statistically significant relationship for those who are socially conservative.
Association of child weight with attendance at a healthy lifestyle service among women with obesity during pregnancy
Authors: Fair Frankie J. , Soltani Hora
Published: February 2024

Women with obesity during pregnancy are at increased risk of excessive gestational weight gain (GWG) and other maternal and infant adverse outcomes, which all potentially increase childhood obesity. This study explored infant weight outcomes for women with a body mass index (BMI) ≥ 35 kg/m² who were offered an antenatal healthy lifestyle service. A retrospective cohort study, including linking data from two separate health care Trusts, was undertaken. Data were collected from maternity records for women with a BMI ≥ 35 kg/m2 referred to an antenatal healthy lifestyle service from 2009 to 2015. The respective child's weight outcome data was additionally collected from health and National Child Measurement Programme records. Univariate logistic regression determined the odds of childhood overweight, obesity and severe obesity according to attendance at the antenatal healthy lifestyle service, GWG and sociodemographic characteristics. Factors significant (p < 0.05) within the univariate analysis were entered into multiple logistic regression models. Among women with a BMI ≥ 35 kg/m², 30.4% of their children were obese at school entry and 13.3% severely obese. Healthy lifestyle service attendance was not associated with childhood overweight or obesity at any point within the univariate analysis. At school age multiple regression analysis showed the odds of overweight and obesity increased with excessive GWG and the odds of obesity decreased with a parent in a professional occupation, additionally having a mother who smoked in pregnancy increased severe obesity. Women should be supported to optimise their BMI before pregnancy. Additionally, rather than exclusively focusing on changing an individual's behaviour, future interventions should consider external influences such as the woman's family, friends and sociodemographic background.
Civil liability for climate change? The proposed tort in Smith v Fonterra with reference to France and the Netherlands
Authors: Downs Sarah
Published: February 2024

As we enter into a period of unprecedented climate instability, litigation is becoming an attractive way to hold private entities accountable for their contribution to global warming. In Smith v Fonterra, New Zealand's Supreme Court is considering whether a common law duty to limit emissions should form part of New Zealand's environmental protection framework. This follows the development of several civil liability mechanisms for environmental damage in overseas jurisdictions. This article examines the implementation of civil liability for climate damage in France and the Netherlands, illustrating the difficulties of effectively dealing with climate change, and its destabilising effect on the law. France implements civil liability mostly on the basis of traditional tort rules, which function to severely restrict its scope. Conversely, the Dutch judiciary introduced a due diligence obligation that requires corporate strategies to be sufficiently in line with international obligations regarding emissions. The latter approach carries more promise, demonstrating that for private entities to be held civilly liable for their contribution to climate change, there must be significant departure from traditional legal doctrine, perhaps in the direction of climate due diligence.
The Relationships Between Absorption, Alterability and Granulation of Coarse Aggregates from Different Lithologies from Southern Brazil
Authors: Ceccato Haline Dugolin , Back Ana Helena , Sagrilo Amanda Vielmo , Nummer Andrea Valli , Pinheiro Rinaldo José Barbosa , Baroni Magnos
Published: February 2024

This paper studies the mathematical and statistical correlations between absorption, alterability, and granulation of aggregates from different lithological origins in southern Brazil. In order to achieve this goal, a petrographic analysis of the aggregates was carried out, in addition to a qualitative evaluation of granulation/alterability and absorption tests for the 1/2” (12.5 mm), 3/8” (9.5 mm), and #4 (4.75 mm) sieve. Statistical analysis relied on the Shapiro-Wilk and Breusch-Pagan tests, using R-Studio software. The results show that the variables “granulation” and “alteration” exhibit satisfactory correlations with the variable “absorption”, indicating that the larger the grain size the lower the absorption, while the higher the alteration the higher the absorption. The more the particle size decreases, the greater the variable “absorption” can explain “granulation”. Regarding the alteration and absorption degree, the analysis was not feasible, since  the analyzed group that included high absorption and low alteration volcanic rocks could modify the trend, contradicting the consensus that the more altered the rock, the more it absorbs. Overall, the employed methodology proved to be satisfactory for the database analyzed, with the suggestion of increasing the number of samples in future studies.
Espectro de manejo farmacológico de la infección por viruela del mono durante el brote de 2022
Authors: Coriat-Cruz Natalia , Moreno-Gómez Freddy , Cepeda-Londoño Sofía
Published: February 2024

Para esta revisión de la literatura, se describieron las propuestas planteadas para el manejo farmacológico de la infección por viruela del mono (Mpox) durante el brote de 2022. Con ese objetivo, se realizó una búsqueda sistematizada de la literatura utilizando las palabras claves: infections, monkeypox, therapeutics, treatment efficacy en Medline, a través de PubMed, donde se identificaron 54 artículos publicados desde 2001 a 2023, de los cuales se seleccionaron 26 para ser incluidos en los resultados. Se encontró que los tratamientos más documentados para tratar la infección por Mpox fueron el tecovirimat, seguido del cidofovir y del brincidofovir. El tecovirimat fue la opción terapéutica más segura y eficaz, con la capacidad en reducir la carga viral del Mpox con una tasa de supervivencia de al menos un 90 %. Sin embargo, ninguno de los tres medicamentos los ha aprobado la Administración de Alimentos y Medicamentos de los Estados Unidos para el tratamiento del Mpox, por lo que se reconoce la importancia de llevar a cabo estudios dirigidos para establecer esquemas de tratamiento mundial, considerando que el Mpox es una potencial arma biológica para todo el planeta.
Adaptive Tracking Control of Robotic Manipulator Subjected to Actuator Saturation and Partial Loss of Effectiveness
Authors: Ngo Van-Tam , Liu Yen-Chen
Published: February 2024

This paper introduces an adaptive control design tailored for robotic systems described by Euler–Lagrange equations under actuator saturation and partial loss of effectiveness. The adaptive law put forth not only retains conventional control properties but also extends its scope to effectively address challenges posed by actuator saturation and partial loss of effectiveness. The framework’s primary focus is on bolstering system robustness, thereby ensuring the achievement of uniformly ultimate bounded tracking errors. The stability and convergence of the system’s behavior are rigorously established through the application of the Lyapunov analysis technique. Moreover, the effectiveness and superiority of the introduced framework are compellingly demonstrated through a series of practical simulations and experimental instances.
Investigation on Mechanical and Fracture Behavior of Magnesium Composite Reinforced With Hybrid Fly Ash Particulates Synthesized via Friction Stir Processing Route
Authors: Sagar Prem , Sangwan Sushma , Handa Amit
Published: February 2024

Utilizing waste materials like fly ash in the creation of lightweight magnesium metal matrix composites with a high strength-to-weight ratio is encouraged by the rising demand for in-expensive reinforcements. In the current study, friction stir processing (FSP) was employed to synthesize magnesium surface composites via incorporating hybrid reinforcement particles, including nano titanium carbide and fly ash. The synthesized composite material underwent examination through microscopic images of the stir zone and assessments of microhardness, tensile strength, compressive strength, electrical and thermal conductance, and wear behavior. The results revealed a notable refinement in grain size and a simultaneous improvement in mechanical properties. Notably, there was a substantial increase in wear resistance attributed to the increased hardness and uniform dispersion of hybrid reinforcements within the surface composite. The results demonstrate that the inclusion of reinforcements in magnesium-based alloy led to an enhancement in fracture toughness, mitigation of crack propagation, and an overall improvement in fracture resistance to catastrophic failure.
Combined Cycle Power Plant Economic Evaluation With Hydrogen and Ammonia As Alternate Fuel
Authors: Pichandi Muruganandam , Nandagopal Pugalenthi , Duerr Matthias , Singh Surendra
Published: February 2024

In Power Generation (PG) Industry, the global Original Equipment Manufacturers (OEMs) are focusing to lower their carbon emissions to reduce the impact of global warming to meet the famous Paris agreement goals and targets. At present approximately 25% of Green House Gases (GHG) are emitted during electricity generation, in that 62% contributed by coal & natural gas power plants [1]. Current Gas Turbines (GTs) burn Natural gas (NG) as primary fuel which contains Carbons, obviously emits CO2 as byproduct. The whole industry is investing time and money to research on reducing CO2 emission close to zero by 2040 and checking the feasibilities of using alternate fuels in power generation.

The current study reported here does not consider any design or technology changes required to use H2 or NH3 as an alternate/blending fuel for GTs but attempts to provide some understandings and directions on cost perspective. The approach of this study is to blend the different types of H2 or NH3 with NG as fuel, evaluate the life cycle cost of combined cycle power plant and other benefits like decarbonization advantages, etc. As the H2 or NH3 fuel is classified in different color codes based on the source of production process, the study considered Black/Grey/Blue/Green Hydrogen and Grey/Blue/Green Ammonia types only. PG Industry will focus on availability of Green Hydrogen/Ammonia as the production process does not emit CO2. However, a recent market study points out that Green H2 and NH3 are costlier than NG fuel. The goal of H2 or NH3 industry is to reduce the production cost of Green H2 or NH3 to make cost competitive technologies.

This study will provide insights to Gas Turbine OEMs to predict the feasible H2 or NH3 blend with NG on their engines with the existing technical capabilities by considering the cost benefits and savings based on geographical CO2 penalty rates.

Additionally, OEMs will get understandings on H2 or NH3 fuel selection among different types and can focus to reduce the production cost of green H2 or NH3 to make as economically feasible alternate fuel in GTs.
Experimental Analysis and Reduced Order Modelling of Merging Flames
Authors: Dutta Subrata , Chakraborty Arnab , Mukherjee Auronil , Mondal Sirshendu
Published: February 2024

The present study investigates the dynamics of merging flames, a prevalent phenomenon in reacting flow systems. We employ two different model order reduction techniques to uncover the underlying spatiotemporal features: Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD). These approaches extract dominant flame modes, frequencies, and coherent structures within the reacting zone. We capture the intricate behavior of merging flames by conducting experiments with candle flames, which serve as a simplified yet representative model. By applying DMD to high-dimensional flame data, we successfully extracted coherent structures and dominant modes of variability. This allowed us to characterize the frequencies and spatial structures of the merging flame dynamics in more detail. Additionally, we utilized DMD to construct reduced-order models, which accurately captured the dominant flame modes. These models enable us to predict future flame behavior and design effective control strategies for flame stabilization. The combined use of DMD and POD enhances the analysis by comprehensively understanding the merging flame behavior. DMD uncovers the temporal evolution and characteristic frequencies, while POD identifies the spatial structures and energy distribution among different modes. This integrated approach allows us to construct reduced-order models that accurately capture the dominant flame modes and their corresponding frequencies, facilitating future predictions and control strategies for flame stabilization.
Design of Cooling Air Flow and Thermal Analysis for an Afterburner V-Gutter
Authors: Aadhithya M. Azith , Rao K. V. L. Narayana , Davis Antonio , Degaonkar Girish K.
Published: February 2024

Modern military aircraft engines are designed for high thrust, low specific fuel consumption, small engine size, and high thrust-to-weight ratio. Afterburner is a thrust augmentation device that is used in all modern military aircraft engines. Afterburners are required for aircrafts to take-off from short runways with heavy payloads and to perform combat manoeuvres. Light up and flame stabilization are the key requirements for any afterburner design. From the literature review, V-gutters are known to be the best flame holding devices based on the blockage, flame spread and combustion stability criteria. For the fifth-generation aero engines, the gas temperature at the entry of the afterburner system is higher than the V-gutter material’s allowable limit. Typical turbine entry gas temperatures are of order of 1850 K and reduces to a value of 1100 K at afterburner inlet which necessitates cooling of the V-gutter structure. Uncooled or bare v-gutters are prone to oxidation and damage due to thermal fatigue. The cooling of v-gutter helps to prevent the oxidation and improve the life.

In this work, various cooling design configurations for the given V-gutter have been investigated using jet impingement and film cooling techniques. This study aims to develop a cooling arrangement to reduce the average uncooled V-gutter metal temperature from 950 K to less than 750 K by using the bypass air at 3 bar pressure and 550 K temperature. The corresponding average cooling effectiveness of 0.5 is to be achieved. The design of experiments (DOE) methods used for computational studies like Monte Carlo and Montgomery to validate and analyse the designs are computationally intensive and time consuming. Hence, a parametric approach is used for optimization of cooling flow design to achieve the desired temperatures and cooling effectiveness. Conjugate Heat Transfer (CHT) analysis is performed on four distinct cooling configurations with different cooling hole diameters and their arrangement. The first three cooling configurations 1 to 3 do not meet the design requirement. The metal temperature of the V-gutter for cooling design configuration 4a is in the range of 699 K – 859 K with an average metal temperature of 788 K. The cooling design configuration 4b showed the best cooling performance with the V-gutter metal temperature in the range of 580 K – 840 K and an average temperature of 755 K. The corresponding cooling effectiveness achieved is 0.53 with lowest cooling air mass flow requirement is 0.45% of afterburner inlet flow. Thus, it is concluded that the V-gutter cooling configuration 4b meets the design intend.
Enhancing Turbine Inlet Temperature Prediction in Single Shaft Combined Cycle Power Plants Using Soft Sensor: A Grey-Box Modelling Approach
Authors: Nandagopal Pugalenthi , More Manjunath , Relan Rishi , Singh Gurdev
Published: February 2024

Measuring the turbine inlet temperature (TIT) in gas turbines is daunting due to the exceptionally high temperatures involved. Using thermocouples is not a cost-effective solution for directly measuring TIT, and their durability over extended periods is also a challenge. Online, near real-time accurate prediction of TIT and its close-loop feedback control is critical due to its significant impact on the rate of power generation and on the lifespan of the hot gas path components in gas turbines. Any increase in TIT can cause a reduction in their lifespan, while a decrease can result in a power loss for the customer. To compute TIT, mass and energy balance approaches are used iteratively online in near real-time environment, which relies on continuous measurement of critical signals from gas turbines. These signals include ambient conditions, gas turbine (GT) output, fuel flow, compressor outlet temperature, turbine exit temperature etc.

In a multi-shaft combined cycle power plant, gas turbine power and steam turbine power are measured separately, simplifying the prediction of gas turbine inlet temperature (TIT). However, in a single-shaft power plant, where both turbines’ power output is combined, predicting TIT becomes challenging. Accurate TIT prediction is crucial for effective gas turbine control in single-shaft combined cycle units. Therefore, a rigorous validation methodology using gas turbine fleet data is necessary to ensure efficient operation.

A new approach for predicting TIT in single-shaft power plants has been developed and validated using data from a multi-shaft plant. The paper describes the methodology, called the Heuristic Transfer function, which utilizes prior domain information for TIT prediction and its validation process using fleet data. Despite using the Heuristic Transfer function, the accuracy and variance of the predicted TIT over time did not meet acceptable thresholds.

To address the concerns of prediction inaccuracy and non-stationarity over time, a novel approach is proposed in the paper. It involves combining the baseline heuristic transfer function with a stochastic model to achieve accurate and time-invariant predictions. The stochastic model is developed using residuals from the heuristic transfer function, providing a more robust and reliable TIT prediction method.
High-Speed Centrifugal Compressor Performance Evaluation With Leaning Diffuser Vane Configurations
Authors: Niveditha Porika , Das Shyama Prasad
Published: February 2024

The diffuser vane of the high-speed centrifugal compressor is subjected to lean in the current study’s numerical analyses.Lean can be defined as a shift in the stagger angle in the vane’s span-wise direction. Three different leans, including lean at the vane’s leading edge, trailing edge, and lean with regard to the centroid of the vane, are examined in the current study. When compared to the base scenario, a diffuser with a lean on CG of −4° and +4° improved the isentropic efficiency of the compressor by 4.7% while maintaining a stable operating range. When compared to a vaned diffuser without lean, the maximum flow limit is raised by adding lean to the diffuser. In the case of leading edge lean, static pressure recovery improved by 1.63% and 0.98% at −4° and +4° lean angles, respectively, as compared to a vaned diffuser without lean pressure recovery at the design condition.
Secondary Losses Mitigation using End-Wall Contouring for LPT Nozzle Vane Cascade
Authors: Koiri Maurya Shivkumar , Mistry Chetan S.
Published: February 2024

By applying the inventive forms of the end-wall between the turbine vane/blade passage, known as end-wall contouring, sought to solve the flow aerodynamics near the end-wall area of the vane/blade. The benefits of a contoured end-wall are not restricted to the area immediately adjacent to it; they also contribute to an improvement in the vane/blade’s overall performance. But careful design is necessary due to the LP turbine’s complicated flow and different operating conditions. The primary goals of this paper were to investigate secondary flow creation and its impact on the flow field as well as to identify the region where end-wall contouring placement can help to lessen unfavorable characteristics in terms of losses. The flow behavior close to the end-wall region is significantly impacted by the incidence angle change from negative to positive. Losses are reduced when the incidence angle is negative, while they significantly increase when the incidence angle is positive. Utilizing the curved end-wall, the cross-passage pressure gradient is systematically managed to aid lower losses. Pitch-wise mass flow average secondary kinetic energy and total pressure loss coefficient were used as benchmarks to assess improvements in secondary flow loss. The selected contoured end-wall case showed 25 and 4.68 percent of Pitch-wise mass flow average secondary kinetic energy and total pressure loss coefficient improvement compare to the baseline case without end-wall contouring.
Numerical Simulation and Aerodynamics of a Fuel Flexible Injector for Micro-Gas Turbine Engines
Authors: Uniyal Shivam , Jamod Preetam , Divyansh Ayush , Singh Saket , K. P. Shanmugadas
Published: February 2024

The present work focuses on developing a novel injector concept for a fuel-flexible micro gas turbine engine that is sized for 1 kN thrust requirements. The lean burn fuel injection design is adopted from the available modern aero-engine combustors. The injector hardware comprises an assembly of pilot and main swirlers, which are arranged in clockwise and counter-clockwise directions having multiple fuel passages in between. The pilot consists of two axial swirlers arranged in clockwise and counterclockwise direction and main consists of one axial and two radial swirlers arranged in clockwise and counter-clockwise direction. As the name suggests both the liquid and gaseous fuel can be used in the assembly either separately or simultaneously. Both the fuels can be alternatively used depending on the thrust or required power operating conditions. The injector is designed using based on the area mass flow split ratio. The mass flow split of 24:76 is distributed between the pilot and main geometry. A simplex nozzle is used for atomizing the liquid fuel with an annular channel having plurality of swirling vanes around it for gaseous fuel makes up the pilot. The main injector has annular toroidal passageways for both liquid and gaseous fuel after an air resist path, which prevents the impingement of main liquid fuel on the wall of pilot. By iterating through several swirler geometrical parameters, numerical studies are made to optimize the recirculation zone structure that can atomize the liquid phase. The CFD formulation is based on the Reynolds-Averaged Navier-Stokes (RANS) equations for accounting turbulence with 0.075 kg/s mass flow rate having a pressure drop of 4% with the atmospheric pressure inside the injector as operating conditions. Standard k-ε model is practiced in computing and optimizing the results. The computational domain of diameter 100 mm, length 80 mm for the inlet and 200 mm, 160 mm for the outlet is used for capturing the aerodynamics of pilot. For main, the computational domain of diameter 100 mm, length 120 mm for the inlet and 200 mm, 200 mm for the outlet is used. The grid independence study for the injector assembly is also performed with varying number of elements from 1.7 million to 6.6 million and employing hybrid meshing method in order to get a suitable mesh for all the iterations. Recirculation zones are captured pilot, main and injector individually. After optimization and variation through various parameters mentioned below, the pilot and main is combined which formed a central toroidal recirculation zone (CTRZ) having a forward and a backward stagnation point with a counter-rotating shear layer at the injector exit. The crucial parameters for the formation of CTRZ’s optimization is the distance that acts as a mixing length between the exit pilot flare and main venturi exits and flow split between the pilot and main injector swirlers.
Internal and External Flow Characteristics on Variation of Swirl Strength for a Fuel Flexible Injector for Micro Gas Turbine Engines
Authors: Verma Abhishek , Jamod Preetam , Uniyal Shivam , Divyansh Ayush , K. P. Shanmugadas
Published: February 2024

The internal and external aerodynamics of fuel flexible lean burn gas turbine injector is numerically investigated to obtain a detailed understanding of the recirculation zone and shear layer characteristics. The injector geometry consists of a main and pilot swirlers that are organized in clockwise and anticlockwise orientations, with several fuel tubes interspersed. Two axial swirlers are positioned in the pilot in a clockwise and anticlockwise direction, while one axial and two radial swirlers are arranged in the main in a clockwise and anticlockwise manner. The area mass flow split ratio is used to construct the injector. There is a 30:70 mass flow split between the main geometry and the pilot geometry. The central toroidal recirculation zone (CTRZ) characteristics are captured for different swirl numbers, for pilot, main and the full injector. Individual recirculation zones are formed at the pilot and main mixers and they combine to form the required single CTRZ at full injector exit. The swirl number of swirlers of main and pilot was varied keeping other parameters constant and it is observed that a slight change in swirl number can impact changes in flow characteristics and CTRZ formation of both mixers of injector.
Aerodynamic Design Improvement of Centrifugal Compressor for Turbocharger Application
Authors: Purushothaman Kirubakaran , Varghese David , Chandramohan Kishore Kumar , Pandurangi Vidyadheesh , Pratap Ajay , Prasad D. Kishore
Published: February 2024

This paper focuses on the design improvement of a baseline centrifugal compressor used in a turbocharger. Centrifugal compressors are favored for their compactness, high pressure ratio output, and wide operating range. The baseline compressor was initially tested and achieved 72% efficiency and 17% surge margin. However, scope for improvement of efficiency and choke mass flow was identified in the new design. Geometric modifications were made to geometric parameters such as impeller blade angle progressions, impeller sweep back angle, vane wrap angle, and impeller exit width. The volute cross-section area was also reduced to improve overall efficiency. Through these modifications, a 5% improvement in efficiency and 3% improvement in choke mass flow were achieved. The modified compressor, tested in a gas stand facility, demonstrated an efficiency of 77% compared to the baseline’s 72% efficiency. These results highlight the importance of geometric parameters in optimizing the performance of centrifugal compressors in turbocharger applications.
Effects of the Swirl Field on the Structure, Planner Drop Sizing and Large-Scale Instabilities of Flow-Blurring Spray
Authors: Gupta Abhishek Kumar , Yadav Keshav , Soni Surendra Kumar , Mishra Yogeshwar Nath , De Santanu
Published: February 2024

Effective atomisation is a governing parameter in a liquid-based gas turbine. Incorporating the swirling air with the spray influences the spray structure, drop dispersion, and large-scale unsteadiness. Therefore, reliable measurement of drop sizes, spray structure, and large-scale instabilities are necessary for the detailed analysis of the complex interaction of the spray droplets in the swirl airfield. We aim to investigate the spray structure, drop sizing, and large-scale unsteadiness of a flow-blurring (FB) spray under swirl airfield conditions. In previous studies, the drop size distribution in FB sprays in a stagnant medium has been characterized based on the point measurement tool, namely Phase Doppler Particle Analyzer (PDPA). However, the PDPA measurement is time-consuming, suffers issues related to multiple scattering in the dense region of the spray, and provides only the time-averaged statistics. Herein, we characterize FB spray under the influence of an external swirling air stream using structured laser illumination planar imaging (SLIPI) technique. The SLIPI technique eliminates unwanted optical signals due to the multiple scattering and provides shot-to-shot variations of the drop size mapping and spray structure.

A lab-scale experimental setup consisting of a centrally mounted FB atomiser with co-annular swirl air passage is operated at a fixed air-liquid mass ratio but with different swirl velocities. Following 1p-SLIPI technique, simultaneous Mie and LIF signals are recorded using two cameras, which are eventually used to obtain two-dimensional droplet Sauter mean diameter (SMD) contours. The calibration constant for the LIF/Mie ratio is deduced using PDPA measurements. The ensemble of instantaneous images is utilized for the proper orthogonal decomposition (POD) analysis to investigate the spatio-temporal features of the large-scale structure. The role of the swirling air on the different types of large-scale instabilities is explained based on the POD modes and energy contributions by the individual modes.
Studies on Unsteady Turbulence Flow Characteristics Associated With Stator-Rotor Interaction Originated Thermal Flow Phenomena Using a High Order LES Model
Authors: Biswas Debasish , Jimbo Tomohiko
Published: February 2024

Unsteady turbulence phenomena caused by stator-rotor interaction in today’s gas turbines which operates at higher temperature to meet the demand of increase in cycle performance by creating severe heat load in the turbine stages is a challenging problem worth paying attention. To avoid the damage of the material from high mean flow temperature cooling of both end-walls and the blades is very much essential. Understanding of the aerodynamics involved is important to implement the cooling technique. To study these phenomena 3-D unsteady Navier-Stokes analysis of a turbine stage is carried out as a base case. The experimentally observed effect of hot streak on the surface temperature distribution of the rotor blade and the unsteady pressure fluctuation associated with stator-rotor interaction are very well predicted by the numerical results. Since the flow associated with stator-rotor interaction is highly unsteady in nature, it is very important to have some understanding of the unsteady turbulence characteristics (unsteady nature of turbulence production and its dissipation and the corresponding fluctuation of pressure and temperature) in this type of thermal flow phenomena. After comparison of computed and experimental results, in our study emphasis is put to understand the unsteady turbulence characteristics based on turbulence production and its dissipation and the corresponding Q-criterion associated with stator-rotor interaction thermal flow phenomena.
Experimental Investigation of a Concentrated Photovoltaic System Integrated With Water Sprinkler Generating Electricity and Hot Water
Authors: Vyas Meet J. , Bhatt Devam , Shah Dev , Patel Lay , Banker Nitin
Published: February 2024

Power generation through solar photovoltaic (PV) is quite attractive due to direction generation of power from radiation and simplicity in construction. The major concern of the solar PV is 10–15% efficiency, i.e. larger land area requirement per kW of power generation. Concentrated solar PV system is one of the options to enhance the power generation in unit area. But the implication is increase in panel temperature, in turn, reducing the cell efficiency. The researchers proposed cooling of panels using water, air, phase change materials etc. to maintain lower temperature. This paper presents experimental investigation of a concentrating solar PV integrated with water sprinkler to enhance power and generate hot water. The experimentation has been performed in Ahmedabad, Gujarat (23.02°N, 72.57°E). Result analysis of various configurations of solar panels with and without concentrators and water sprinkler has been performed. To make sure the repeatability, each configuration has been experimented for two different days. Performance parameters such as electrical efficiency and overall efficiency have been used to compare the different configurations. The result analysis shows enhancement of power along with the generation of hot water in comparison to conventional solar PV system.