bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the Temperature Profile Optimization Method for Thermal Conditioning of Large Bodies
Authors: Sezmen Ramazan Aykut 
Published: September 2024

Abstract
The performance of various systems, such as electronic cards, avionics, and propulsion systems, is highly depend on thermal effects and the system’s temperature. As the operational temperatures of these systems undergo changes throughout their life cycles, the characterization of temperature-dependent performances necessitates different tests, including performance tests under controlled temperature conditions. Obtaining desired temperature distribution for smaller components, such as avionics or electronic components can be achieved within several hours or even minutes inside the industrial furnaces. Conversely, temperature conditioning for larger structures, such as propulsion systems, may require several days or even weeks. The process of temperature conditioning, conducted under a constant furnace temperature is a time-consuming operation when it is considered in terms of project workflow. In an effort to decrease the duration of these last long and inefficient constant furnace temperature processes, a time optimization study is proposed which is aiming to obtain varying furnace temperature profile to acquired needed temperature distribution throughout these large structures. Three-dimensional, two-dimensional, and axisymmetric finite element models are established for a comprehensive examination of a large-scale system by considering the nature of the problem. Outcomes from these distinct finite element models leads to the determination that the axisymmetric model is most suited for the ensuing optimization study. The constraints and the objective of the optimization are clearly defined. An iterative procedure is conducted between the optimization tool and heat transfer analysis solver. As a result of the study, required time for the temperature conditioning is decreased by almost 50% by using the obtained varying furnace temperature profiles instead of using constant furnace temperature. It is noteworthy that diverse constraints and objectives may be implemented within the developed model to accommodate case-specific exigencies.
Enhancing Thermal Performance in a PCM Heatsink Assembly By Incorporating Fins and Copper Oxide Nanoparticles
Authors: Jones Austin , Darabi Jeff 
Published: September 2024

Abstract
Phase Change Materials (PCMs) have become a common addition to heatsinks to help control the temperature of electronic components during operation. PCM heatsinks utilize the latent heat of materials like paraffin wax to mitigate the rising temperature of electronic components as the PCM undergoes melting. This allows electronics to operate for extended periods without needing to shut down before they reach their maximum operating temperature. However, these materials typically exhibit low thermal conductivity. To enhance the overall thermal conductivity of the system, fins can be added to the assembly. Another approach involves incorporating metallic nanoparticles into the pure wax. Both methods aim to strike a balance between effective thermal conductivity and available latent heat. This paper presents experimental and numerical results from a heatsink assembly with two different fin geometries. A constant heat flux is applied to the bottom of the assembly. The thermal effectiveness of this assembly was examined both with and without the addition of pure paraffin wax. Additionally, copper oxide (CuO) nanoparticles were introduced to the wax and their effects were studied. The experimental data collected from the wax with added CuO nanoparticles were used to validate a finite element model created using ANSYS Fluent. The study also investigates the impact of removing the fins and adding copper oxide nanoparticles on the thermal effectiveness of the heat sink assembly. The heat source interface temperature was lowered by 8°C when fins were added, but this resulted in a reduction in latent heat storage of the assembly. The addition of CuO nanoparticles without the use of fins was found to reduce the operating temperature of the heat source interface by 5°C.
Convergent and Divergent Shell and Tube TES Partially Filled With PCM and Metal Foam
Authors: Buonomo Bernardo , Golia Maria Rita , Manca Oronzio , Nardini Sergio , Plomitallo Renato Elpidio 
Published: September 2024

Abstract
The ongoing European energy crisis and the imperative to reduce carbon emissions have driven the exploration of energy storage systems. This research focuses on latent heat thermal energy storage systems (LTES). LTESs, utilizing phase change materials (PCMs) combined with metal foams, offer advantages over sensible thermal energy storage systems. Metal foams enhance the thermal conductivity of PCMs, creating a system with a fast-absorbing energy zone defined by low thermal resistance. The study investigates a vertical shell and tube geometry with a non-constant internal tube section, filled by a combination of PCM embedded in a metal foam and PCM alone. A variable is introduced to define the partial filling ratio. The Brinkman-Forchheimer-extended Darcy model and enthalpy-porosity theory are employed to analyze heat transfer and phase change processes. Ansys-Fluent provides numerical solutions. Examining natural convection impact on heat transfer, the study explores the effects of the inclination angle variation inside the shell and tube. Numerical simulations report melting time, average temperature, and specific energy storage rate. Results demonstrate enhanced heat transfer in LTES with metal foam and PCM especially in converging tube cases. The findings demonstrate that the convergent configuration with s = 1/2, in the case with an inclination angle of 10°, achieves maximum stored energy 50% faster than the identical configuration without a section variation.
Design of Test Bench for the Analysis of Efficiency and Effectiveness of Extended Surfaces for Educational Purpose
Authors: Jervis Freddy X. , Cando Gabriela , Moreira Daniel , Moreira Cesar , Zabala Gonzalo 
Published: September 2024

Abstract
Hands-on experience such as laboratory practices can be beneficial as students gain a better perspective of the theory presented in class. However, acquisition of these types of equipment can be expensive for institutions in developing countries. The heat transfer phenomena are an imperative topic to understand for undergraduate engineering students in the Mechanical Engineering curriculum as well as other engineering disciplines. For these reasons, a test bench design and experimentation project for heat transfer phenomena is being carried out. In this study, the design of a test bench for the analysis of extended surfaces under varying convection conditions is proposed. The test bench proposed uses locally available materials as well as an open-source interface (Arduino-based). The test bench offers the ability to easily mount and dismount different fin models and arrays. An experimental procedure is developed over three types of fins: straight rectangular fins, rectangular pin fins, and rectangular fin array under natural and forced convection. The design also contemplates a flow velocity controller that will allow the study of forced convection under steady state and transient conditions. The test bench follows national safety standards so that students can freely manipulate the different arrays under laboratory technician supervision. A cost analysis between importing the equipment to the assembly with local suppliers was also conducted. The design is expected to contribute to engineering programs providing a cost-effective solution for a hands-on laboratory experience.
Exergy Analysis on an Innovative Vapor-Compression Ejector Heat Pump Water Heater
Authors: Spitzenberger Jeremy , Ma Hongbin 
Published: September 2024

Abstract
Ejector-driven systems are thermally operated and capable of utilizing excess thermal energy to aid in boosting the overall efficiency of the system. Traditionally, ejectors have been implemented into systems for cooling purposes, however, recent studies have demonstrated their potential to increase the efficiency in heat pump systems. In this study a theoretical model is developed, its performance is modeled, and an exergy analysis is performed on an innovative vapor compression ejector heat pump (VCEHP) for the purposes of water heating. The analysis is performed assuming the evaporator temperature of 6.5 °C, and a low temperature evaporator (LTE) temperature of 20 °C, for condenser outlet temperature range of 40–60 °C, with R134a acting as the working fluid. The ejector model incorporated was compared to previous experimental studies utilizing R134a, and the predicted coefficient of performance (COP) and back pressures to within 4.01%. The results of the VCEHP are compared to that of a traditional vapor compression heat pump (VCHP) water heater. The theoretical results have shown that the incorporation of the ejector can lead to a 22.78% increase in the system heating COP.
Pyrolysis and Heat Release Rate Predictions of Heated Solid Specimens in the OSU Apparatus
Authors: Farouk Bakhtier , Cappello Garrett , Burns Michael 
Published: September 2024

Abstract
A mathematical model is being developed to describe the pyrolysis (degradation of solid materials exposed to external heat) and heat release rate of aircraft cabin materials in the OSU (Ohio State University) apparatus. The OSU apparatus is used to expose aircraft interior cabin materials to an incident radiant heat flux of 35 kW/m2. This test determines if the material complies with FAR 25.853 requirements. The OSU heat release rate apparatus is a Federal Aviation Administration (FAA) designated combustion test instrument for testing the heat release rate of aircraft cabin materials. The results of the research completed include transient solutions of the flow-field variables (velocity, temperature, and pressure) within the fluid domain of the OSU apparatus using ANSYS FLUENT. A model of the basic overall geometry with a surface-to-surface radiation model was also developed. For the ongoing pyrolysis simulations of the specimens, a reduced computational domain has been considered that will include the effect of the radiant heaters (along a boundary of the proposed domain (Figure 6), the specimen holder within the OSU apparatus bounding walls.
Transport and Flow Characteristics of Graphene-Doped Nanofluids at Moderate Temperatures in Double-Pipe Heat Exchangers
Authors: Gaudio Philip J. , Skelly Jerome M. , Yavuzturk Cy C. , Chiasson Andrew D. , Johnson Drew W. 
Published: September 2024

Abstract
The objective of this study is to assess the thermal and hydraulic characteristics of water-based graphene-doped nanofluids experimentally as well as analytically in counter-flow concentric tube heat exchangers for the purpose of evaluating their viability as compared to pure water and other water-based solutions such as methanol and propylene glycol. A concentric pipe system (copper-PVC) was configured such that graphene-doped primary fluid flowed in the inner tube (copper), while a secondary flow of de-ionized water was introduced in the annulus. The nanofluids in volume fractions of 0.001, 0.005, 0.01, and 0.015 of graphene nanoplatelets were tested using a base fluid of deionized water at varying temperatures of 30°C, 45°C, 60°C, and 75°C, with the secondary fluid set to a constant temperature of 4°C lower. The increase in the volume fraction of the graphene nanoplatelets showed an appreciable corresponding increase in the thermal conductivity of the nanofluid. However, the flow regime was adversely affected as it transitioned from turbulent to laminar owing to increased viscosity of the nanofluid. This flow transition resulted in a corresponding decrease in the convective heat transfer coefficient. The research results have implications on the assessment and understanding of heat transfer characteristics of graphene based nanofluids in various heat transfer processes. The results show that in the turbulent flow regime the incremental improvements in the thermal conductivity of the nanofluid are far outweighed by disproportionally large increases in pumping power requirements. However, it is observed that appropriately doped graphene nanofluids appear to have advantages over propylene glycol in the laminar flow regime and may be considered as a replacement.
Novel cellular functions of Cys
2
-His
2
zinc finger proteins in anthracnose development and dissemination on pepper fruits by
Colletotrichum scovillei
Authors: Fu Teng , Song Yong-Won , Gao Guoyang , Kim Kyoung Su 
Published: September 2024

ABSTRACT

Colletotrichum
species are notorious for causing anthracnose on many fruits, leading to significant economic losses worldwide. As a model, we functionally characterized cys2-his2 (C
2
H
2
) zinc finger proteins (CsCZFs) in
Colletotrichum scovillei
, a major causal agent of pepper fruit anthracnose in many countries. In all, 62 CsCZFs were identified by
in silico
genomic analysis. Twelve were selected based on their expression profiles to generate targeted deletion mutants for functional investigation.
ΔCsczf1
markedly reduced conidiation and constitutive expression of
CsCZF1
partially recovered conidiation in an asexual reproduction-defective mutant,
ΔCshox2
. Deletion of
CsCZF12
, orthologous to the calcineurin-responsive transcription factor
Crz1
, impaired autophagy in
C. scovillei. ΔCsczf9
was defective in surface recognition, appressorium formation, and suppression of host defenses.
CsCZF9
was identified as an essential and novel regulator under the control of the mitogen-activated protein kinase (CsPMK1) in an early step of appressorium development in
C. scovillei
. This study provides novel insights into
CsCZF
-mediated regulation of differentiation and pathogenicity in
C. scovillei
, contributing to understanding the regulatory mechanisms governing fruit anthracnose epidemics.

IMPORTANCE

The phytopathogenic fungus
Colletotrichum scovillei
is known to cause serious anthracnose on chili pepper. However, the molecular mechanism underlying anthracnose caused by this fungus remains largely unknown. Here, we systematically analyzed the functional roles of cys2-his2 zinc finger proteins (CsCZFs) in the dissemination and pathogenic development of this fungus. Our results showed that CsCZF1 plays an important role in conidiation and constitutive expression of CsCZF1 restored conidiation in an asexual reproduction-defective mutant,
ΔCshox2
. The CsCZF9, a novel target of the mitogen-activated protein kinase (CsPMK1), is essential for surface recognition to allow appressorium formation and suppression of host defenses in
C. scovillei
. The CsCZF12, orthologous to the calcineurin-responsive transcription factor Crz1, is involved in the autophagy of
C. scovillei
. Our findings reveal a comprehensive mechanism underlying CsCZF-mediated regulation of differentiation and pathogenicity of
C. scovillei
, which contributes to the understanding of fruit anthracnose epidemics and the development of novel strategies for disease management.
Phage-antibiotic synergy suppresses resistance emergence of
Klebsiella pneumoniae
by altering the evolutionary fitness
Authors: Qin Kunhao , Shi Xing , Yang Kai , Xu Qiuqing , Wang Fuxing , Chen Senxiong , Xu Tingting , Liu Jinquan , Wen Wangrong , Chen Rongchang , Liu Zheng , Cui Li , Zhou Kai 
Published: September 2024

ABSTRACT

Phage-antibiotic synergy (PAS) represents a superior treatment strategy for pathogen infections with less probability of resistance development. Here, we aim to understand the molecular mechanism by which PAS suppresses resistance in terms of population evolution. A novel hypervirulent
Klebsiella pneumoniae
(KP) phage H5 was genetically and structurally characterized. The combination of H5 and ceftazidime (CAZ) showed a robust synergistic effect in suppressing resistance emergence. Single-cell Raman analysis showed that the phage-CAZ combination suppressed bacterial metabolic activities, contrasting with the upregulation observed with phage alone. The altered population evolutionary trajectory was found to be responsible for the contrasting metabolic activities under different selective pressures, resulting in pleiotropic effects. A pre-existing
wcaJ
point mutation (

wcaJ
G949A

) was exclusively selected by H5, conferring a fitness advantage and up-regulated activity of carbohydrate metabolism, but also causing a trade-off between phage resistance and collateral sensitivity to CAZ. The
wcaJ
point mutation was counter-selected by H5-CAZ, inducing various mutations in
galU
that imposed evolutionary disadvantages with higher fitness costs, and suppressed carbohydrate metabolic activity. H5 and H5-CAZ treatments resulted in opposite effects on the transcriptional activity of the phosphotransferase system and the ascorbate and aldarate metabolism pathway, suggesting potential targets for phage resistance suppression. Our study reveals a novel mechanism of resistance suppression by PAS, highlighting how the complexity of bacterial adaptation to selective pressures drives treatment outcomes.

IMPORTANCE

Phage-antibiotic synergy (PAS) has been recently proposed as a superior strategy for the treatment of multidrug-resistant pathogens to effectively reduce bacterial load and slow down both phage and antibiotic resistance. However, the underlying mechanisms of resistance suppression by PAS have been poorly and rarely been studied. In this study, we tried to understand how PAS suppresses the emergence of resistance using a hypervirulent
Klebsiella pneumoniae
(KP) strain and a novel phage H5 in combination with ceftazidime (CAZ) as a model. Our study reveals a novel mechanism by which PAS drives altered evolutionary trajectory of bacterial populations, leading to suppressed emergence of resistance. The findings advance our understanding of how PAS suppresses the emergence of resistance, and are imperative for optimizing the efficacy of phage-antibiotic therapy to further improve clinical outcomes.
Diverse BCR usage and T cell activation induced by different COVID-19 sequential vaccinations
Authors: Wang Junxiang , Li Kaiyi , Wang Yuan , Lin Zhengfang , Li Weidong , Cao Jinpeng , Mei Xinyue , Wei Rui , Yang Jinglu , Zhai Xiaobing , Huang Deyi , Zhou Kaiwen , Liang Xinyue , Wang Zhongfang 
Published: September 2024

ABSTRACT

Limited knowledge is available on the differences in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specific antibody breadth and T cell differentiation among different COVID-19 sequential vaccination strategies. In this study, we compared the immunogenicity of the third different dose of COVID-19 vaccines, such as mRNA (I-I-M), adenoviral vector (I-I-A), and recombinant protein (I-I-R) vaccines, in terms of the magnitude and breadth of antibody response and differentiation of SARS-CoV-2-specific T and B cells. These studies were performed in the same clinical trial, and the samples were assessed in the same laboratory. IGHV1-69, IGHV3-9, and IGHV4-34 were the dominant B cell receptor (BCR) usages of the I-I-M, I-I-A, and I-I-R groups, respectively; the RBD
+
B cell activation capacities were comparable. Additionally, the I-I-R group was characterized by higher numbers of regulatory T cells, circulating T follicular helper cells (cTFH) – cTFH1 (CXRC3
+
CCR6
-
), cTFH1-17 (CXRC3
+
CCR6
+
), cTFH17 (CXRC3
-
CCR6
+
), and cTFH-CM (CD45RA
-
CCR7
+
), and lower SMNE
+
T cell proliferative capacity than the other two groups, whereas I-I-A showed a higher proportion and number of virus-specific CD4
+
T cells than I-I-R, as determined in ex vivo experiments. Our data confirmed different SARS-CoV-2-specific antibody profiles among the three different vaccination strategies and also provided insights regarding BCR usage and T/B cell activation and differentiation, which will guide a better selection of vaccination strategies in the future.

IMPORTANCE

Using the same laboratory test to avoid unnecessary interference due to cohort ethnicity, and experimental and statistical errors, we have compared the T/B cell immune response in the same cohort sequential vaccinated by different types of COVID-19 vaccine. We found that different sequential vaccinations can induce different dominant BCR usage with no significant neutralizing titers and RBD
+
B-cell phenotype. Recombinant protein vaccine can induce higher numbers of regulatory T cells, circulating TFH (CTFH)1, CTFH17, and CTFH-CM, and lower SMNE
+
T-cell proliferative capacity than the other two groups, whereas I-I-A showed higher proportion and number of virus-specific CD4
+
T cells than I-I-R. Overall, our study provides a deep insight about the source of differences in immune protection of different types of COVID-19 vaccines, which further improves our understanding of the mechanisms underlying the immune response to SARS-CoV-2.
Cell shape and division septa positioning in filamentous
Streptomyces
require a functional cell wall glycopolymer ligase CglA
Authors: Bhowmick Sukanya , Viveros Ruth P. , Latoscha Andreas , Commichau Fabian M. , Wrede Christoph , Al-Bassam Mahmoud M. , Tschowri Natalia 
Published: September 2024

ABSTRACT

The cell wall of monoderm bacteria consists of peptidoglycan and glycopolymers in roughly equal proportions and is crucial for cellular integrity, cell shape, and bacterial vitality. Despite the immense value of
Streptomyces
in biotechnology and medicine as antibiotic producers, we know very little about their cell wall biogenesis, composition, and functions. Here, we have identified the LCP-LytR_C domain protein CglA (Vnz_13690) as a key glycopolymer ligase
,
which specifically localizes in zones of cell wall biosynthesis in
S. venezuelae
. Reduced amount of glycopolymers in the
cglA
mutant results in enlarged vegetative hyphae and failures in FtsZ-rings formation and positioning. Consequently, division septa are misplaced leading to the formation of aberrant cell compartments, misshaped spores, and reduced cell vitality. In addition, we report our discovery that c-di-AMP signaling and decoration of the cell wall with glycopolymers are physiologically linked in
Streptomyces
since the deletion of
cglA
restores growth of the
S. venezuelae disA
mutant at high salt. Altogether, we have identified and characterized CglA as a novel component of cell wall biogenesis in
Streptomyces
, which is required for cell shape maintenance and cellular vitality in filamentous, multicellular bacteria.

IMPORTANCE

Streptomyces
are our key producers of antibitiotics and other bioactive molecules and are, therefore, of high value for medicine and biotechnology. They proliferate by apical extension and branching of hyphae and undergo complex cell differentiation from filaments to spores during their life cycle. For both, growth and sporulation, coordinated cell wall biogenesis is crucial. However, our knowledge about cell wall biosynthesis, functions, and architecture in
Streptomyces
and in other Actinomycetota is still very limited. Here, we identify CglA as the key enzyme needed for the attachment of glycopolymers to the cell wall of
S. venezuelae
. We demonstrate that defects in the cell wall glycopolymer content result in loss of cell shape in these filamentous bacteria and show that division-competent FtsZ-rings cannot assemble properly and fail to be positioned correctly. As a consequence, cell septa placement is disturbed leading to the formation of misshaped spores with reduced viability.