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CFD-Based Optimization of a Shell-and-TUBE Heat Exchanger

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Fluid Dynamics & Materials Processing 2023年第11期19卷 2761-2775页

作者： Juanjuan Wang Jiangping Nan Yanan Wang Xi’an Traffic Engineering Institute Xi’an710300China

The main objective of this study is the technical optimization of a Shell-and-TUBE Heat Exchanger(STHE).In order to do so,a simulation model is introduced that takes into account the related gas-phase circulation.Then,simulation verification experiments are designed in order to validate the model.The results show that the tem-peraturefield undergoes strong variations in time when an inlet wind speed of 6 m/s is considered,while the heat transfer error reaches a minimum of 5.1%.For an inlet velocity of 9 m/s,the heat transfer drops to the lowest point,while the heat transfer error reaches a maximum,i.e.,9.87%.The pressure drop increasesfirst and then decreases with an increase in the wind speed and reaches a maximum of 819 Pa under the 9 m/s wind speed con-dition.Moreover,the pressure drops,and the heat transfer coefficient increases with the Reynolds number.

关键词： Heat exchanger aerodynamics engineeringfluid mechanics TUBE heat transmission heat transfer model numerical simulation

Plasma membrane H^(+)-ATPases-mediated cytosolic proton gradient regulates pollen TUBE growth

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Journal of Integrative Plant Biology 2020年第12期62卷 1817-1822页

作者： Wei Chen Peng‐Fei Jia Wei‐Cai Yang Hong‐Ju Li State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biologythe Chinese Academy of SciencesBeijing 100101China College of Advanced Agricultural Sciences University of Chinese Academy of SciencesBeijing 100049China

The polar growth of pollen TUBEs is essential for the delivery of sperm cells during fertilization in angiosperms. How this polar growth is regulated has been a long-standing question. An in vitro pharmacological assay previously implicated proton flux in pollen TUBE growth, although genetic and cellular supporting evidence was lacking. Here, we report that protons form a gradient from the pollen TUBE tip to the shank region and this gradient is generated by three members of Arabidopsis H^(+)-ATPases (AHAs). Genetic analysis suggested that these AHAs are essential for pollen TUBE growth, thus providing new insight into the regulation of polar growth.

关键词： gradient TUBE supporting

Spatiotemporal expression of leukemia inhibitory factor receptor protein during neural TUBE development in embryos with neural TUBE defects

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Neural Regeneration Research 2020年第4期15卷 705-711页

作者： Dong An Xiao-Wei Wei He-Nan Zhang Dan Liu Wei Ma Zheng-Wei Yuan Key Laboratory of Health Ministry for Congenital Malformation Shengjing HospitalChina Medical UniversityShenyangLiaoning ProvinceChina Department of Pediatrics The First Hospital of China Medical UniversityShenyangLiaoning ProvinceChina

Leukemia inhibitory factor receptor(LIFR),as a neuroregulatory cytokine receptor,generally shows a neuroprotective effect in central nervous system injuries.In this study,to understand the effect of LIFR on pathogenesis of neural TUBE defects,we explored spatiotemporal expression of LIFR at different stages of fetal development in normal and neural TUBE defect embryos.Spina bifida aperta was induced with all-trans retinoic acid on embryonic day 10 in rats,and the spatiotemporal expression of LIFR was investigated in spina bifida aperta rats and healthy rats from embryonic day 11 to 17.Real time-polymerase chain reaction and western blot assay were used to examine mRNA and protein expression of LIFR in healthy control and neural TUBE defect embryos.Results of the animal experiment demonstrated that expression of LIFR protein and mRNA in the spinal cords of normal rat embryos increased with embryonic development.LIFR was significantly downregulated in the spinal cords of spina bifida aperta rats compared with healthy rats from embryonic days 11 to 17.Immunohistochemical staining showed that the expression of LIFR in placenta and spinal cord in spina bifida aperta rat embryos was decreased compared with that in control embryos at embryonic day 15.Results from human embryo specimens showed that LIFR mRNA expression was significantly down-regulated in spinal cords of human fetuses with neural TUBE defects compared with normal controls at a gestational age of 24 to 33 weeks.The results were consistent with the down-regulation of LIFR in the animal experiments.Our study revealed spatiotemporal changes in expression of LIFR during embryonic neurulation.Thus,LIFR might play a specific role in neural TUBE development.All animal and human experimental procedures were approved by the Medical Ethics Committee of Shengjing Hospital of China Medical University,China(approval No.2016PS106K)on February 25,2016.

关键词： amniotic fluid development embryogenesis leukemia inhibitory factor receptor nerve regeneration neural TUBE defect placenta spatiotemporal expression spina bifida aperta spinal cord serum

Experimental study on combined buoyant-thermocapillary flow along with rising liquid film on the surface of a horizontal metallic mesh TUBE

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Frontiers in Energy 2020年第1期14卷 114-126页

作者： Manuel J.GOMES Ning MEI Marine Engineering Section College of EngineeringOcean University of ChinaQingdao266100China

Temperature distribution and variation with time has been considered in the analysis of the influences of the initial level of immersion of a horizontal metallic mesh TUBE in the liquid on combined buoyant and thermocapillary flow.The combined flow occurs along with the rising liquid film flow on the surface of a horizontal metallic mesh TUBE.Three different levels of immersion of the metallic mesh TUBE in the liquid have been tested.Experiments of 60 min in duration have been performed using a heating metallic TUBE with a diameter of 25 mm and a length of 110 mm,sealed outside with a metallic mesh of 178 mm by 178 mm,and distilled water.These reveal two distinct flow patterns.Thermocouples and infrared thermal imager are utilized to measure the temperature.The level of the liquid free surface relative to the lower edge of the TUBE is measured as angleθ.The results show that for a smallerθangle,or a low level of immersion,with a relatively low heating power,it is possible to near fully combine the upwards buoyant flow with the rising liquid film flow.In this case,the liquid is heated only in the vicinity of the TUBE,while the liquid away from the flow region experiences small changes in temperature and the system approaches steady conditions.For largerθangles,or higher levels of immersion,a different flow pattern is noticed on the liquid free surface and identified as the thermo-capillary(Marangoni)flow.The rising liquid film is also present.The higher levels of immersion cause a high temperature gradient in the liquid free surface region and promote thermal stratification;therefore the system could not approach steady conditions.

关键词： rising liquid film combined flow thermocapillary flow buoyant flow metallic mesh TUBE horizontal TUBE

Towards an understanding of plant reproductive isolation:uncovering the species-specific signal for pollen TUBE guidance

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Science China(Life Sciences) 2020年第4期63卷 620-622页

作者： Xin-Qi Gao Huan Guan Xian-Sheng Zhang National Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTai’an 271018China

Fertilization produces diploid zygote as the initiation of new diploid organism by fusing two haploid gametes(sperm and egg cell).Different from animals,plants in angiosperms produce immobile sperms in pollen/pollen TUBE(male gametophyte).Whereas,the egg cell is located in the female gametophyte(embryo sac)that consists of two female gametes(egg and central cells)and accessory cells(synergids and antipodals).Embryo sac is embedded in the ovule of ovary,which is an enlarged basal portion of the pistil.The growth of pollen TUBE provides a strategy for the immobile sperm approaching the egg cell.After pollination,pollen germinates at the surface of the stigma and produces pollen TUBE.It grows through the transmitting tract of the style and emerges from it to enter the ovary in response to certain attracting cues from the ovule.

关键词： attracting approaching TUBE

Conf irmation of endotracheal TUBE placement using disposable f iberoptic bronchoscopy in the emergent setting

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World Journal of Emergency Medicine 2019年第4期10卷 210-214页

作者： Avir Mitra Asaf Gave Kelsey Coolahan Thomas Nguyen Department of Emergency Medicine Mount Sinai Beth IsraelIcahn School of MedicineNew Jersey 08043USA Department of Surgery Critical Care Mount Sinai Beth IsraelIcahn School of MedicineNew York 10009USA

BACKGROUND:Patients intubated in the prehospital setting require quick and definitive confirmation of endotracheal (ET) TUBE placement upon arrival to the emergency department (ED).Direct and adjunct strategies exist,but each has limitations and there is no definitive gold standard.The utility of bronchoscopy in ED intubation has been studied,but scant literature exists on its use for ET TUBE confirmation.This study aims to assess effectiveness,ease and speed with which ET TUBE placement can be confirmed with disposable fiberoptic bronchoscopy.METHODS:Emergency medicine residents recruited from a 3-year urban residency program received 5 minutes of active learning on a simulation mannequin using a disposable,flexible Ambu aScope interfaced with a monitor.With residents blinded,the researcher randomly placed the ET TUBE in the trachea,esophagus or right mainstem.Residents identified ET TUBE position by threading the bronchoscope through the TUBE and viewing distal anatomy.Each resident underwent 4 trials.Accuracy,speed and perceptions of difficulty were measured.RESULTS:Residents accurately identified the location of the ET TUBE in 88 out of 92 trials (95.7%).The median time-to-guess was 7.0 seconds,IQR (5.0-10.0).Average perceived difficulty was 1.6 on a scale from 1-5 (1 being very easy and 5 being very difficult).No TUBEs were damaged or dislodged.CONCLUSION:While simulation cannot completely replicate the live experience,fiberoptic bronchoscopy appears to be a quick and accurate method for ET TUBE confirmation.Further studies directly comparing this novel approach to established practices on actual patients are warranted.

关键词： Airway Simulation Bronchoscopy TUBE confi rmation

Coronary CT Angiography Using Low Iodine Delivery Rate and TUBE Voltage Determined by Body Mass Index:Superiority in Clinical Practice

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Current Medical Science 2019年第5期39卷 825-830页

作者： Wang YUAN Ting-ting QU Hui-juan WANG Mei-yu WANG Yuan QU Gang NIU Jian YANG Department of Diagnostic Radiology the First Hospital of Medical Science CentreXi'an Jiaotong UniversityXi'an 710061China Department of Dermatology the Ninth Hospital of Xi'anXi'an 710054China

To explore the feasibility and superiority of iodine delivery rate(IDR)and TUBE voltage determined by patients'body mass index(BMI)in coronary CT angiography(CCTA),a total of 1567 patients undertaking CCTA during Feb.and Dec.2016 were enrolled and divided into two groups.In the control group,the IDR and TUBE voltage were fixed,while in the experimental group,the IDR and TUBE voltage were determined by patients,BMI.The volume of iodinated contrast media(ICM),extravasation rate,extravasation volume,extravasation recovery interval,incidence rate of adverse reactions,effective dose(ED)and image quality of the two groups were compared.The experiments demonstrated that the ICM volume,extravasation rate,extravasation volume,extravasation recovery interval,incidence of adverse reactions and ED were lower or shorter in the experimental group than in the control group,and the differences were statistically significant(all PTUBE voltage based on patients'BMI;low TUBE voltage and IDR are superior to the fixed TUBE voltage and IDR and are worthy of clinical promotion.

关键词： iodinated contrast media iodine delivery rate TUBE voltage ICM extravasation adverse reactions

Cysteine-rich peptides: signals for pollen TUBE guidance, species isolation and beyond

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Science China(Life Sciences) 2019年第9期62卷 1243-1245页

作者： Sheng Zhong Li-Jia Qu State Key Laboratory for Protein and Plant Gene Research Peking-Tsinghua Center for Life Sciences at College of Life SciencesPeking UniversityBeijing 100871China The National Plant Gene Research Center (Beijing) Beijing 100101China

In flowering plants,the two sperm cells are passive cargo transported into the ovule by pollen TUBEs (Zhang et al.,2017).Therefore,the precise guidance of pollen TUBEs is critical for successful double fertilization (Dresselhaus and Franklin-Tong,2013).A series of male-female interactions are required to guarantee the spatiotemporal regulation of pollen TUBE guidance because during growth,pollen TUBEs continuously interact with different female tissues (Zhong et al.,2017;Zhong and Qu,2019).In the past two decades,there has been tremendous progress in elucidating the molecular mechanisms of pollen TUBE guidance regulation,mostly using Arabidopsis thaliana as a model system (Johnson et al.,2019).

关键词： double fertilization pollen TUBE model system

Hybrid reinforced thermoset polymer composite in energy absorption TUBE application:A review

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Defence Technology（防务技术） 2018年第4期14卷 291-305页

作者： A.B.M.Supian S.M.Sapuan M.Y.M.Zuhri E.S.Zainudin H.H.Ya Department of Mechanical and Manufacturing Engineering Universiti Putra Malaysia Laboratory of Bio Composite Technology Institute of Tropical Forestry and Research Products (INTROP)Universiti Putra Malaysia Department of Mechanical Engineering Universiti Teknologi Petronas

The custom of hybridization fibre composite in energy absorption TUBE application has gained the attention of structural crashworthiness in composite material industry. Thus, the approach of this review is to understand the effect in hybridization within metal/synthetic fibre composite, synthetic/synthetic fibre composite and nature/synthetic fibre composite as energy absorption TUBE, which reflects on the energy absorption characteristics and crashworthiness behaviors in previous the study. By way of instance, a wide range of methodology and particular parameter in previous study such as the effect in fibre arrangement, matrix polymer, technique of fabrication, fibre treatment(natural fibre), design in geometry/cross-section and others mechanism of hybrid fibre composite TUBE are highlighted which to comprehend the capability of the mechanical performance and collapsible behavior as sacrificial structure in high-performance structure applications. Moreover, in the recently studies there have been many of the research regarding structural materials as energy absorption TUBE has been introduced such as metal/matrix composites, new alloy metals and polymer composites which intended to evaluate the performance of these materials into circumstance in loading and impact characteristic. Therefore, this review article is trying to explore the research articles related to the effect of hybridization fibres and thermoset polymer as reinforcement for energy absorption TUBE research and expected would provide an information and idea which to expend the knowledge in future study of hybridization effect for energy absorption TUBE, moreover the development for future potential as new hybrid composite fibre materials from the natural/synthetic fibres reinforced composite material in employing of high-performance energy absorption TUBE application is still less discover and highlighted.

关键词： Energy absorption TUBE Hybrid composites Collapse behavior Crashworthiness