• Title/Summary/Keyword: University of Birmingham

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TEM investigation of helium bubble evolution in tungsten and ZrC-strengthened tungsten at 800 and 1000℃ under 40keV He+ irradiation

  • I. Ipatova;G. Greaves;D. Terentyev;M.R. Gilbert;Y.-L. Chiu
    • Nuclear Engineering and Technology
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    • v.56 no.4
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    • pp.1490-1500
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    • 2024
  • Helium-induced defect nucleation and accumulation in polycrystalline W and W0.5 wt%ZrC (W0.5ZrC) were studied in-situ using the transmission electron microscopy (TEM) combined with 40 keV He+ irradiation at 800 and 1000℃ at the maximum damage level of 1 dpa. Radiation-induced dislocation loops were not observed in the current study. W0.5ZrC was found to be less susceptible to irradiation damage in terms of helium bubble formation and growth, especially at lower temperature (800 ℃) when vacancies were less mobile. The ZrC particles present in the W matrix pin the forming helium bubbles via interaction between C atom and neighbouring W atom at vacancies. This reduces the capability of helium to trap a vacancy which is required to form the bubble core and, as a consequence, delays, the bubble nucleation. At 1000 ℃, significant bubble growth occurred in both materials and all the present bubbles transitioned from spherical to faceted shape, whereas at 800 ℃, the faceted helium bubble population was dominated in W.

Mapping of Carbon Flow Distribution in the Central Metabolic Pathways of Clostridium cellulolyticum: Direct Comparison of Bacterial Metabolism with a Soluble versus an Insoluble Carbon Source

  • DESVAUX, MICKAEL,
    • Journal of Microbiology and Biotechnology
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    • v.14 no.6
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    • pp.1200-1210
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    • 2004
  • Metabolic flux analysis was established by adapting previous stoichiometric model developed during growth with cellulose to cell grown with cellobiose for further direct comparison of the bacterial metabolism. In carbon limitation with cellobiose, a shift from acetate-ethanol fermentation to ethanol-lactate fermentation is observed and the pyruvate overflow is much higher than with cellulose. In nitrogen limitation with cellobiose, the cellodextrin and exopolysaccharide overflows are much higher than on cellulose. In carbon and nitrogen saturation with cellobiose, the cellodextrin, exopolysaccharide, and free amino acids overflows reach the highest levels observed but all remain limited on cellulose. By completely shunting the cellulosome, the use of cellobiose allows to reach much higher carbon consumption rates which, in return, highlights the metabolic limitation of C. cellulolyticum. Therefore, the physical nature of the carbon source has a profound impact on the metabolism of C. cellulolyticum and most probably of other cellulolytic bacteria. For cellulolytic bacteria, the use of soluble carbon substrate must carefully be taken into consideration for the interpretation of results. Direct comparison of metabolic flux analysis from cellobiose and cellulose revealed the importance of cellulosome, phosphoglucomutase and pyruvate-ferredoxin oxidoreductase in the distribution of carbon flow in the central metabolism. In the light of these findings, future directions for improvement of cellulose catabolism by this bacterium are discussed.

Study for Frictional Characteristics of graphite lubricants in hot. warm forging (열ㆍ온간 단조에서 그라파이트 윤활제의 마찰 특성에 대한 연구)

  • ;;T.A. Dean
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.4
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    • pp.29-37
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    • 2000
  • At present there are many theories as to how various lubricants used in forging perform the role of reducing friction. Little work has been carried out to determine the validity of these theories for solid lubricants. This paper covers the development and preliminary results of the experiments devised to illustrate the movement of graphite at the workpiece/tool interface in the work forging temperature range. The paper describes the results obtained from upsetting of rings between two flat dies for measurement of lubricant thickness and compaction of graphite for density-pressure relationship. These allowed the lubricant to be exposed to forging conditions and by applying the principles of Male's ring test the simple generation of a value fur friction factor could also be determined. The experiments have been undertaken to examine the behavior of lubricant for shot blasted surface and change of surface roughness. A simple computer model of the interface has been constructed characterizing the graphite layer in an attempt to simulate the boundary mechanics.

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Developing and Testing the Effects of a Psychosocial Intervention on Stress Response and Coping in Korean Breast Cancer Survivors : A Pilot Study (유방암 환자의 스트레스 대응 능력 증진을 위한 심리사회적 중재 재발 및 효과: 예비연구)

  • Kim Cho-Ja;Hur Hea-Kung;Kang Duck-Hee;Kim Bo-Hwan
    • Journal of Korean Academy of Nursing
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    • v.34 no.6
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    • pp.1069-1080
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    • 2004
  • Purpose: The purpose of this study was to develop a socioculturally-appropriate psychosocial intervention program for Korean patients with breast cancer and test its effects on stress, anxiety, depression, and coping strategies. Methods: One group pretest and posttest design was used to test the effects of the intervention. A post-intervention interview was conducted to refine the nature of the intervention. A convenience sample of 10 breast cancer survivors was recruited from the outpatients clinics. Psychosocial intervention was developed to provide the health education, stress management, coping skill training and support weekly(90min) for 6 weeks. Results: There was a significant decrease in stress scores following the intervention(Z= -2.388, p=0.017). However, no significant changes were noted in the use of problem-focused and emotion-focused coping strategies, nor in the changes of anxiety and depression levels. Content analysis of interview data revealed six clusters; changes in perception, changes in problem solving approaches, changes in anger management, changes in life pattern, social support and reduction of perceived stress. Conclusions: Based on quantitative and qualitative data, we recommend the refinements of the intervention in the following areas for future studies: 1) duration, activities, and progression of psychosocial intervention; 2) research design and sample size; and 3) measurements.

Designing ESP Curriculum for EFL Learners at College of Navigation

  • Choi, Seung-Hee
    • Journal of Navigation and Port Research
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    • v.38 no.2
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    • pp.127-134
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    • 2014
  • This paper aims to identify what is needed to improve the English for Specific Purposes(ESP) curriculum for English as a Foreign Language(EFL) college learners at navigation school. Different needs from learners and experienced professionals are identified through diversified methods, and the findings from these are analysed and consolidated from a balanced point of view. For this purpose, putting learners at the centre of analysis, identifying their subjective and objective needs serves as a point of departure in formulating the curriculum. Then, the target situation is analysed according to the short-term aim of getting a job, followed by long-term needs for successfully fulfilling future duties as a pilot. Based on findings, it is suggested that ESP curriculum for learners in navigation studies should be focused on the successful language performance of their actual duties and tasks to be given in the future working situations, rather than on immediate needs for getting a job. In particular, special attention needs to be paid to enhancing learners' productive language competences through a series of hands-on trainings and a wide range of extra-curricular activities, specifically for a higher command of oral communication. For this, not only ESP, curriculum for EGP(English for General Purposes) should be systematically structured as ESP-oriented EGP, and naturally move onto areas of ESP in a coherent manner.

Optimal Ball-end and Fillet-end Mills Selection for 3-Axis Finish Machining of Point-based Surface

  • Kayal, Prasenjit
    • International Journal of CAD/CAM
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    • v.7 no.1
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    • pp.51-60
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    • 2007
  • This paper presents an algorithm of optimal cutting tool selection for machining of the point-based surface that is defined by a set of surface points rather than parametric polynomial surface equations. As the ball-end and fillet-end mills are generally used for finish machining in a 3-axis computer numerical control machine, the algorithm is applicable for both cutters. The optimum tool would be as large as possible in terms of the cutter radius and/or corner radius which maximise (s) the material removal rate (i.e., minimise (s) the machining time), while still being able to machine the entire point-based surface without gouging any surface point. The gouging are two types: local and global. In this paper, the distance between the cutter bottom and surface points is used to check the local gouging whereas the shortest distance between the surface points and cutter axis is effectively used to check the global gouging. The selection procedure begins with a cutter from the tool library, which has the largest cutter radius and/or corner radius, and then adequacy of the point-density is checked to limit the accuracy of the cutter selection for the point-based surface within tolerance prior to the gouge checking. When the entire surface is gouge-free with a chosen cutting tool then the tool becomes the optimum cutting tool for a list of cutters available in the tool library. The effectiveness of the algorithm is demonstrated considering two examples.

Unsteady wind loading on a wall

  • Baker, C.J.
    • Wind and Structures
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    • v.4 no.5
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    • pp.413-440
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    • 2001
  • This paper presents an extensive analysis of unsteady wind loading data on a 18 m long and 2 m high wall in a rural environment, with the wind at a range of angles to the wall normal. The data is firstly analyzed using standard statistical techniques (moments of probability distributions, auto- and cross-correlations, auto- and cross-spectra etc.). The analysis is taken further using a variety of less conventional methods - conditional sampling, proper orthogonal decomposition and wavelet analysis. It is shown that, even though the geometry is simple, the nature of the unsteady flow is surprisingly complex. The fluctuating pressures on the front face of the wall are to a great extent caused by the turbulent fluctuations in the upstream flow, and reflect the oncoming flow structures. The results further suggest that there are distinct structures in the oncoming flow with a variety of scales, and that the second order quasi-steady approach can predict the pressure fluctuations quite well. The fluctuating pressures on the rear face are also influenced by the fluctuations in the oncoming turbulence, but also by unsteady fluctuations due to wake unsteadiness. These fluctuations have a greater temporal and spatial coherence than on the front face and the quasi-steady method over-predicts the extent of these fluctuations. Finally the results are used to check some assumptions made in the current UK wind loading code of practice.

An Investigation into the Historical Context of a Kimono and Its Sartorial Relevance in Western Societies in 2022

  • Elizabeth J, Burton
    • Journal of Fashion Business
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    • v.26 no.6
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    • pp.14-31
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    • 2022
  • Worn by both males and females the kimono is the national dress of Japan. Previous research highlights that this national dress is fading from tradition and evolves to develop with the times and fashion trends. This research aims to investigate what a kimono represents both historically and currently within Western society. The idea of the kimono being more than a national dress representing Japan, the main three themes researched will be (1) Shape (2) Narrative (3) Journey from East to West. Based on both primary and secondary sources this research indicates that there is a strong relationship between the universal increase of kimono wearers in Eastern and Western societies from history through to present day. Primary research is utilised in the form of two types of interviews. Primary outcomes bring a personal perspective to how and why kimono is worn nowadays within Europe. Secondary sources include online lectures held by kimono specialists as well as subject relevant books. From the 19th century where the Dutch were the only European country to trade with Japan, an exchange of fabrics took place which later led to the exchange of: fit, fashion and pattern (primarily within Western womenswear fashion.) This distinct garment never gets discontinued and evolves with social demands within society today.

Individual LPS Responsiveness Depends on the Variation of Toll-like Receptor (TLR) Expression Level

  • JaeKal, Jun;Abraham, Edward;Azam, Tania;Netea, Mihai G.;Dinarello, Charles A.;Lim, Jong-Seok;Yang, Young;Yoon, Do-Young;Kim, Soo-Hyun
    • Journal of Microbiology and Biotechnology
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    • v.17 no.11
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    • pp.1862-1867
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    • 2007
  • An individual's immune response is critical for host protection from many different pathogens, and the responsiveness can be assessed by the amount of cytokine production upon stimulating bacterial components such as lipopolysaccharide (LPS). The difference between individuals in their peripheral blood mononuclear cells (PBMC) responsiveness to LPS, a Gram-negative endotoxin, was investigated from 27 healthy individuals. We observed a large variation in $IFN{\gamma}$ production among different individuals. The PBMC of the consistently three highest and three lowest $IFN{\gamma}$ producers were investigated. Since previous studies described that a single point mutation in the coding region of TLR2 and TLR4 is linked to the individual responsiveness to pathogenic bacterial infections, we first examined the known point mutations in the coding region of $TLR2^{Pro681His}$, $TLR4^{Pro714His}$ located in the cytoplasmic regions of the Toll-like domain as well as $TLR4^{Asp299Gly}$ located in the extracellular region. None of these mutations were associated with an individual's responsiveness to LPS, despite the presence of $TLR4^{Asp299Gly}$ mutation. Further investigation revealed that the variation of PBMC responsiveness to LPS among healthy individuals was due to constitutive expression levels of TLR4 and TLR2. This result is consistent with an aging-related low expression of Toll-like receptors in the mouse model of LPS responsiveness. The present study therefore suggests that the constitutive expression levels of TLR2 and TLR4 may contribute to the individual response to LPS.

Tissue Transglutaminase is Not Involved in the Aggregate Formation of Stably Expressed $\alpha$-Synuclein in SH-SY5Y Human Neuroblastoma Cells

  • Suh, Myung-Duk;Park, Chang-Ha;Kim, Sung-Soo;Kil, Myeng-Og;Lee, Geon-Hee;Johnson, Gail V. W.;Chun, Wan-Joo
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.850-856
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    • 2004
  • Intraneuronal deposition containing $\alpha$-synuclein is implicated in the pathogenesis of synuclein-opathies including Parkinsons disease (PD). Although it has been demonstrated that cytoplas-mic inclusions of wild type $\alpha$-synuclein are observed in the brain of PD patients and that $\alpha$-synuclein mutations such as A30P and A53T accelerate aggregate formation, the exact mech-anism by which $\alpha$-synuclein forms insoluble aggregates is still controversial. In the present study, to understand the possible involvement of tissue transglutaminase (tTG) in aggregate formation of $\alpha$-synuclein, SH-SY5Y cell lines stably expressing wild type or mutant (A30P or A53T) $\alpha$-synuclein were created and aggregate formation of $\alpha$-synuclein was observed upon activation of tTG. The data demonstrated that $\alpha$-synuclein negligibly interacted with tTG and that activation of tTG did not result in the aggregate formation of $\alpha$-synuclein in SH-SY5Y cells overexpressing either wild type or mutant $\alpha$-synuclein. In addition, $\alpha$-synuclein was not modi-fied by activated tTG in situ. These data suggest that tTG is unlikely to be a contributing factor to the formation of aggregates of $\alpha$-synuclein in a stable cell model.