• Title/Summary/Keyword: thermal responses

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Vibration of multilayered functionally graded deep beams under thermal load

  • Bashiri, Abdullateef H.;Akbas, Seref D.;Abdelrahman, Alaa A.;Assie, Amr;Eltaher, Mohamed A.;Mohamed, Elshahat F.
    • Geomechanics and Engineering
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    • v.24 no.6
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    • pp.545-557
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    • 2021
  • Since the functionally graded materials (FGMs) are used extensively as thermal barriers in many of applications. Therefore, the current article focuses on studying and presenting dynamic responses of multilayer functionally graded (FG) deep beams placed in a thermal environment that is not addressed elsewhere. The material properties of each layer are proposed to be temperature-dependent and vary continuously through the height direction based on the Power-Law function. The deep layered beam is exposed to harmonic sinusoidal load and temperature rising. In the modelling of the multilayered FG deep beam, the two-dimensional (2D) plane stress continuum model is used. Equations of motion of deep composite beam with the associated boundary conditions are presented. In the frame of finite element method (FEM), the 2D twelve-node plane element is exploited to discretize the space domain through the length-thickness plane of the beam. In the solution of the dynamic problem, Newmark average acceleration method is used to solve the time domain incrementally. The developed procedure is verified and compared, and an excellent agreement is observed. In numerical examples, effects of graduation parameter, geometrical dimension and stacking sequence of layers on the time response of deep multilayer FG beams are investigated with temperature effects.

Association of selected gene polymorphisms with thermotolerance traits in cattle - A review

  • Hariyono, Dwi Nur Happy;Prihandini, Peni Wahyu
    • Animal Bioscience
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    • v.35 no.11
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    • pp.1635-1648
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    • 2022
  • Thermal stress due to extreme changes in the thermal environment is a critical issue in cattle production. Many previous findings have shown a decrease in feed intake, milk yield, growth rate, and reproductive efficiency of cattle when subjected to thermal stress. Therefore, selecting thermo-tolerant animals is the primary goal of the efficiency of breeding programs to reduce those adverse impacts. The recent advances in molecular genetics have provided significant breeding advantages that allow the identification of molecular markers in both beef and dairy cattle breeding, including marker-assisted selection (MAS) as a tool in selecting superior thermo-tolerant animals. Single-nucleotide polymorphisms (SNPs), which can be detected by DNA sequencing, are desirable DNA markers for MAS due to their abundance in the genome's coding and non-coding regions. Many SNPs in some genes (e.g., HSP70, HSP90, HSF1, EIF2AK4, HSBP1, HSPB8, HSPB7, MYO1A, and ATP1A1) in various breeds of cattle have been analyzed to play key roles in many cellular activities during thermal stress and protecting cells against stress, making them potential candidate genes for molecular markers of thermotolerance. This review highlights the associations of SNPs within these genes with thermotolerance traits (e.g., blood biochemistry and physiological responses) and suggests their potential use as MAS in thermotolerant cattle breeding.

Investigation of the concentration characteristic of RCS during the boration process using a coupled model

  • Xiangyu Chi;Shengjie Li;Mingzhou Gu;Yaru Li;Xixi Zhu;Naihua Wang
    • Nuclear Engineering and Technology
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    • v.55 no.8
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    • pp.2757-2772
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    • 2023
  • The fluid retention effect of the Volume Control Tank (VCT) leads to a long time delay in Reactor Coolant System (RCS) concentration during the boration process. A coupled model combining a lumped-parameter sub-model and a computational fluid dynamics sub-model is currently used to investigate the concentration dynamic characteristic of RCS during the boration process. This model is validated by comparison with experimental data, and the predicted results show excellent agreement with experimental data. We provide detailed fields in VCT and concentration variations of RCS to study the interaction between mixing in VCT and the transient responses of RCS. Moreover, the impacts of the inlet flow rate, inlet nozzle diameter, original concentration, and replenishing temperature of VCT on the RCS concentration characteristic are studied. The inlet flow rate and nozzle diameter of VCT remarkably affect the RCS concentration characteristic. Too-large or too-small inlet flow rates and nozzle diameters will lead to unacceptable long delays. In this work, the optimal inlet flow rate and nozzle diameter of VCT are 5 m3/h and 58.8 mm, respectively. Besides, the impacts of the original concentration and replenishing temperature of VCT are negligible under normal operating conditions.

Treatment of Refractory Melasma with Microwave-generated, Atmospheric-pressure, Non-thermal Nitrogen Plasma

  • Kim, Hyun-Jo;Kim, Heesu;Kim, Young Koo;Cho, Sung Bin
    • Medical Lasers
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    • v.8 no.2
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    • pp.74-79
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    • 2019
  • Periorbital melasma is often refractory to treatment and highly associated with rebound hyperpigmentation or mottled hypopigmentation after laser treatment in Asian patients. In this report, we describe 2 patients with cluster-1 periorbital melasma and 1 patient with cluster-2 periorbital melasma who experienced remarkable clinical improvements after microwave-generated, atmospheric-pressure, non-thermal nitrogen plasma treatments. All patients exhibited limited clinical responses after combination treatments with topical bleaching agents, systemic oral tranexamic acid, and low-fluenced Q-switched neodymium (Nd):yttrium-aluminum-garnet (YAG) lasers. Low-energy nitrogen plasma treatment at 0.75 J elicited remarkable clinical improvement in the periorbital melasma lesions without post-laser therapy rebound hyperpigmentation and mottled hypopigmentation. We deemed that a single pass of nitrogen plasma treatment at 0.75 J induces mild microscopic thermal tissue coagulation and modification within the epidermis while preserving the integrity of the basement membrane in patients with periorbital melasma. Accordingly, nitrogen plasma-induced dermal tissue regeneration could play a role in the treatment of melasma lesions.

Fluctuation of Temperature Induces Pathogenicity of Streptococcus iniae and Changes of Immunology Related Genes of Korean Rockfish, Sebastes schlegeli

  • EunYoung Min;Seon-Myeong Jeong;Hyun-Ja Han;Miyoung Cho
    • Korean Journal of Ecology and Environment
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    • v.56 no.4
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    • pp.420-429
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    • 2023
  • This study was designed to examine the immune response in Korean rockfish during water temperature fluctuation and to elucidate the factors contributing to streptococcal pathogenesis in cultured Korean rockfish, S. schlegeli. We investigated cumulative mortality against Streptococcus iniae (FP5228 strain) infection in the exposed Korean rockfish (39.7±5.8 g) to environmentally relevant temperature (Control, 23℃; High temperature, 28℃ and 23℃ and 28℃ with 12 hours interval exchange, 23↔28℃) for 48 hours. Also, the expression of the mRNA related to the immune response genes (heat shock protein 70, interleukin1β, lysozyme g-type and thioredoxin-like 1) were measured in spleen and head kidney by real-time PCR analysis in the exposed fish to thermal stress. In this study, the combined stress with bacterial challenge in fishes exposed to thermal stress lowered the survival rate than that of control (23℃). The cumulative mortality in the group of control, 28℃ and 23↔28℃ was 24%, 24% and 40% (P<0.05), respectively. Also, thermal stress modulated the mRNA level of immune related genes; heat shock protein 70, interleukin-1β, lysozyme g-type and thioredoxin-like 1 in Korean rockfish. The present study indicates that a high and sudden water temperature change affect immune responses and reduce the disease resistance in Korean rockfish.

Thermal post-buckling measurement of the advanced nanocomposites reinforced concrete systems via both mathematical modeling and machine learning algorithm

  • Minggui Zhou;Gongxing Yan;Danping Hu;Haitham A. Mahmoud
    • Advances in nano research
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    • v.16 no.6
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    • pp.623-638
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    • 2024
  • This study investigates the thermal post-buckling behavior of concrete eccentric annular sector plates reinforced with graphene oxide powders (GOPs). Employing the minimum total potential energy principle, the plates' stability and response under thermal loads are analyzed. The Haber-Schaim foundation model is utilized to account for the support conditions, while the transform differential quadrature method (TDQM) is applied to solve the governing differential equations efficiently. The integration of GOPs significantly enhances the mechanical properties and stability of the plates, making them suitable for advanced engineering applications. Numerical results demonstrate the critical thermal loads and post-buckling paths, providing valuable insights into the design and optimization of such reinforced structures. This study presents a machine learning algorithm designed to predict complex engineering phenomena using datasets derived from presented mathematical modeling. By leveraging advanced data analytics and machine learning techniques, the algorithm effectively captures and learns intricate patterns from the mathematical models, providing accurate and efficient predictions. The methodology involves generating comprehensive datasets from mathematical simulations, which are then used to train the machine learning model. The trained model is capable of predicting various engineering outcomes, such as stress, strain, and thermal responses, with high precision. This approach significantly reduces the computational time and resources required for traditional simulations, enabling rapid and reliable analysis. This comprehensive approach offers a robust framework for predicting the thermal post-buckling behavior of reinforced concrete plates, contributing to the development of resilient and efficient structural components in civil engineering.

Thermal impacts on transcriptome of Pectoralis major muscle collected from commercial broilers, Thai native chickens and its crossbreeds

  • Yuwares Malila;Tanaporn Uengwetwanit;Pornnicha Sanpinit;Wipakarn Songyou;Yanee Srimarut;Sajee Kunhareang
    • Animal Bioscience
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    • v.37 no.1
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    • pp.61-73
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    • 2024
  • Objective: The main objective of this study was to define molecular mechanisms associated with thermal stress responses of chickens from commercial broilers (BR, Ross 308), Thai native chickens (NT) and crossbreeds between BR×NT (H75). Methods: Twenty days before reaching specific market age, chickens from each breed were divided into control and thermal-stressed groups. The stressed groups were exposed to a cyclic thermal challenge (35℃±1℃ for 6 h, followed by 26℃±1℃ for 18 h) for 20 days. Control group was raised under a constant temperature of 26℃±1℃. Pectoralis major (n = 4) from each group was collected for transcriptome analysis using HiSeq Illumina and analysis of glycogen and lactate. Gene expression patterns between control and thermal-stressed groups were compared within the same breeds. Results: Differentially expressed transcripts of 65, 59, and 246 transcripts for BR, NT, and H75, respectively, were revealed by RNA-Seq and recognized by Kyoto encyclopedia of genes and genomes database. Pathway analysis underlined altered glucose homeostasis and protein metabolisms in all breeds. The signals centered around phosphatidylinositol 3-kinase (PI3K)/Akt signaling, focal adhesion, and MAPK signaling in all breeds with slight differences in molecular signal transduction patterns among the breeds. An extensive apoptosis was underlined for BR. Roles of AMPK, MAPK signaling and regulation of actin cytoskeleton in adaptive response were suggested for H75 and NT chickens. Lower glycogen content was observed in the breast muscles of BR and NT (p<0.01) compared to their control counterparts. Only BR muscle exhibited increased lactate (p<0.01) upon exposure to the stress. Conclusion: The results provided a better comprehension regarding the associated biological pathways in response to the cyclic thermal stress in each breed and in chickens with different growth rates.

Vibroacoustic analysis of stiffened functionally graded panels in thermal environments

  • Ashish K. Singh;Anwesha Pal;Shashi Kumar;Anuja Roy;Atanu Sahu
    • Structural Engineering and Mechanics
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    • v.89 no.5
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    • pp.437-452
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    • 2024
  • Functionally graded materials (FGMs) have gained substantial attention from researchers due to their exceptional strength and thermal resistance. Their utilization in the aviation and automobile industries has significantly improved the efficiency of various structural components. Moreover, stiffened panels find wide applications in aerospace and automobile structures and these panels are frequently exposed to extreme environments. It is from this perspective that our research is focused on analysing the vibroacoustic response of stiffened functionally graded panels subjected to external dynamic excitations in a thermal environment. In the present research work, a finite element model is developed to conduct the dynamic analysis of functionally graded stiffened panels using the first-order shear deformation theory. Subsequently, a boundary element based model is also developed and coupled with the finite element model to investigate the sound radiation behaviour of those panels in a thermal environment. The material properties of FG stiffened panels are considered as temperature dependent, while the thermal environment is assumed to be acting as linearly varying through the panel's thickness. The present investigation aim to compare the vibroacoustic responses of different panels due to stiffener orientations, material compositions, power law indices and plate thicknesses at various temperatures. The research findings highlight the significant impact of addition of stiffeners, its orientation and material compositions on the sound radiation characteristics of these panels under thermal environments. The present numerical model can easily be employed for analysing the sound radiation behaviour of other types of flat or curved stiffened panels having arbitrary geometry and boundary conditions.

Non-linear free and forced vibration analysis of sandwich nano-beam with FG-CNTRC face-sheets based on nonlocal strain gradient theory

  • Arani, Ali Ghorbanpour;Pourjamshidian, Mahmoud;Arefi, Mohammad
    • Smart Structures and Systems
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    • v.22 no.1
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    • pp.105-120
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    • 2018
  • In this paper, the nonlinear free and forced vibration responses of sandwich nano-beams with three various functionally graded (FG) patterns of reinforced carbon nanotubes (CNTs) face-sheets are investigated. The sandwich nano-beam is resting on nonlinear Visco-elastic foundation and is subjected to thermal and electrical loads. The nonlinear governing equations of motion are derived for an Euler-Bernoulli beam based on Hamilton principle and von Karman nonlinear relation. To analyze nonlinear vibration, Galerkin's decomposition technique is employed to convert the governing partial differential equation (PDE) to a nonlinear ordinary differential equation (ODE). Furthermore, the Multiple Times Scale (MTS) method is employed to find approximate solution for the nonlinear time, frequency and forced responses of the sandwich nano-beam. Comparison between results of this paper and previous published paper shows that our numerical results are in good agreement with literature. In addition, the nonlinear frequency, force response and nonlinear damping time response is carefully studied. The influences of important parameters such as nonlocal parameter, volume fraction of the CNTs, different patterns of CNTs, length scale parameter, Visco-Pasternak foundation parameter, applied voltage, longitudinal magnetic field and temperature change are investigated on the various responses. One can conclude that frequency of FG-AV pattern is greater than other used patterns.

Residents' Responses on Indoor Environmental Efficiency and Spatial Function of Front Balcony in Apartments (아파트 전면발코니의 실내환경 조절효과 및 공간기능 -전면발코니를 실내공간과 통합개조한 경우와의 비교-)

  • 최윤정
    • Journal of the Korean Home Economics Association
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    • v.42 no.5
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    • pp.93-106
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    • 2004
  • The purpose of this study is to make clear the indoor environmental efficiency and spatial function of the front balcony in apartments using responses from residents'. An interview survey carried out during the 14/sup th/∼24/sup th/ of January 2003, and a questionnaire survey was given during the 17/sup th/∼29/sup th/of January. Interviewees consisted of 31 residents living in renovated apartments, which had the front balcony added onto the living room. The respondents of the questionnaire survey consisted of 37 residents living in ordinary apartments with an existing front balcony. The residents living in ordinary apartments show relatively positive responses on the indoor thermal environment during winter, glare by daylight, and outdoor noise. The average heating charges of the renovated apartments came out to be more expensive than the ordinary apartments. In most renovated apartments, the living area converted from front balcony was used as the same functions ('space for drying the laundry', 'storage space', or 'space for cultivating of flower pots') of ordinary front balcony. From the results of this study, it is undesirable to renovate the front balcony as an addition to the livingroom.