Mechanics of milling 48-2-2 gamma titanium aluminide

Accurate and fast prediction of cutting forces is important in high-performance cutting in the aerospace industry. Gamma titanium aluminide (gamma-TiAl) is a material of choice for aerospace and automotive applications due to its superior thermo-mechanical properties. Nevertheless, it is a difficult to machine material. This article presents the prediction of cutting forces for Ti-48Al-2Cr-2Nb (48-2-2) gamma-TiAl in milling process using orthogonal to oblique transformation technique. The novelty of this paper lies in reporting the orthogonal database of 48-2-2 gamma-TiAl. Fundamental cutting parameters such as shear stress, friction angle and shear angle are calculated based on experimental measurements. Friction coefficients are identified for two different coating conditions which are AlTiN, and AlCrN on carbide tools. Predicted results are validated with the experimental cutting forces during end milling and ball-end milling operations for different cutting conditions. The simulated results showed good agreement with the experimental results, which confirms the validity of the force modelWOS:000568177300002Scopus - Affiliation ID: 60105072Science Citation Index ExpandedQ2ArticleUluslararası işbirliği ile yapılan - EVETAğustos2020YÖK - 2019-2

Mycobacterium tuberculosis ecology in Venezuela: epidemiologic correlates of common spoligotypes and a large clonal cluster defined by MIRU-VNTR-24

<p>Abstract</p> <p>Background</p> <p>Tuberculosis remains an endemic public health problem, but the ecology of the TB strains prevalent, and their transmission, can vary by country and by region. We sought to investigate the prevalence of <it>Mycobacterium tuberculosis </it>strains in different regions of Venezuela. A previous study identified the most prevalent strains in Venezuela but did not show geographical distribution nor identify clonal genotypes. To better understand local strain ecology, we used spoligotyping to analyze 1298 <it>M. tuberculosis </it>strains isolated in Venezuela from 1997 to 2006, predominantly from two large urban centers and two geographically distinct indigenous areas, and then studied a subgroup with MIRU-VNTR 24 loci.</p> <p>Results</p> <p>The distribution of spoligotype families is similar to that previously reported for Venezuela and other South American countries: LAM 53%, T 10%, Haarlem 5%, S 1.9%, X 1.2%, Beijing 0.4%, and EAI 0.2%. The six most common shared types (SIT's 17, 93, 605, 42, 53, 20) accounted for 49% of the isolates and were the most common in almost all regions, but only a minority were clustered by MIRU-VNTR 24. One exception was the third most frequent overall, SIT 605, which is the most common spoligotype in the state of Carabobo but infrequent in other regions. MIRU-VNTR homogeneity suggests it is a clonal group of strains and was named the "Carabobo" genotype. Epidemiologic comparisons showed that patients with SIT 17 were younger and more likely to have had specimens positive for Acid Fast Bacilli on microscopy, and patients with SIT 53 were older and more commonly smear negative. Female TB patients tended to be younger than male patients. Patients from the high incidence, indigenous population in Delta Amacuro state were younger and had a nearly equal male:female distribution.</p> <p>Conclusion</p> <p>Six SIT's cause nearly half of the cases of tuberculosis in Venezuela and dominate in nearly all regions. Strains with SIT 17, the most common pattern overall may be more actively transmitted and SIT 53 strains may be less virulent and associated with reactivation of past infections in older patients. In contrast to other common spoligotypes, strains with SIT 605 form a clonal group centered in the state of Carabobo.</p

Ti6Al4V metal cutting chip formation experiments and modelling over a wide range of cutting speeds

Measured forces, chip geometry and tool temperatures from machining a mill annealed Ti6Al4V at cutting speeds mainly from 1 to 100 m/min, but in some cases down to 0.1 m/min, are reported, as well as mechanical testing of the material. Finite element simulations with inputs the measured flow stress, and subsequently a small high temperature strain hardening recovery correction, and a failure model calibrated from the cutting tests at speeds from 1 to 10 m/min, give satisfactory agreement with the higher speed tests once surface strain hardening and damage from the previous pass of the tool are taken into account. This paper’s originality is firstly to show that more complicated flow stress models involving large strain softening are not needed provided shear failure is included; and secondly its failure model: this proposes a non-zero failed shear stress depending on local pressure and temperature. The simulations provide relations between tool mechanical and thermal loading and cutting conditions to aid process improvement

Transmission Pattern of Drug-Resistant Tuberculosis and Its Implication for Tuberculosis Control in Eastern Rural China

OBJECTIVE: Transmission patterns of drug-resistant Mycobacterium tuberculosis (MTB) may be influenced by differences in socio-demographics, local tuberculosis (TB) endemicity and efficaciousness of TB control programs. This study aimed to investigate the impact of DOTS on the transmission of drug-resistant TB in eastern rural China. METHODS: We conducted a cross-sectional study of all patients diagnosed with drug-resistant TB over a one-year period in two rural Chinese counties with varying lengths of DOTS implementation. Counties included Deqing, with over 11 years' DOTS implementation and Guanyun, where DOTS was introduced 1 year prior to start of this study. We combined demographic, clinical and epidemiologic information with IS6110-based restricted fragment length polymorphism (RFLP) and Spoligotyping analysis of MTB isolates. In addition, we conducted DNA sequencing of resistance determining regions to first-line anti-tuberculosis agents. RESULTS: Of the 223 drug-resistant isolates, 73(32.7%) isolates were identified with clustered IS6110RFLP patterns. The clustering proportion among total drug-resistant TB was higher in Guanyun than Deqing (26/101.vs.47/122; p,0.04), but not significantly different among the 53 multidrug-resistant isolates (10/18.vs.24/35; p,0.35). Patients with cavitary had increased risk of clustering in both counties. In Guanyun, patients with positive smear test or previous treatment history had a higher clustering proportion. Beijing genotype and isolates resistant to isoniazid and/or rifampicin were more likely to be clustered. Of the 73 patients with clustered drug-resistant isolates, 71.2% lived in the same or neighboring villages. Epidemiological link (household and social contact) was confirmed in 12.3% of the clustered isolates. CONCLUSION: Transmission of drug-resistant TB in eastern rural China is characterized by small clusters and limited geographic spread. Our observations highlight the need for supplementing DOTS with additional strategies, including active case finding at the village level, effective treatment for patients with cavities and drug susceptibility testing for patients at increased risk for drug-resistance

神戸市の河川の景観に対する視覚的判定に関する調査研究

本研究は, 神戸市西区伊川谷地域を縦貫する伊川を事例としてとりあげ, 住民の河川景観に関する視覚的選好を分析, 考察したものである。筆者らの同地域の先行調査ではこの地域の景観の中で最も保護すべきもののひとつとして, 伊川があげられていた。今回の調査では, 同地域の2地区の住民に各地区内の伊川とその周辺の景観デザイン例を見せてその選好を調査するとともにSD法を用いて分析した。調査結果として, 総合評価, 規模及び密度が主たる因子として抽出された。住民の選好傾向としては, 河川敷を散策しながら田園風景を楽しめるような自然的取り扱いが求められレクリェーション施設としても簡潔で自然的なデザインと親水性が求められた。In this research, residents from two districts (Ikegami and Zenkai) located in the Ikawadani region, west part of Kobe City were interviewed in order to evaluate the landscape of some design proposal for the Ikawa river which flows across this region. In previous research, 2) the river was assessed by residents as on of the most important landscapes to protect. Residents were asked to select the best, better, good and the worst, worse, bad landscapes, then the Semantic Differential Technique was applied to measure their visual perception in detail. From the result, factor structure of the semantic judgements and their interpretation were obtained by factor analysis. The main factors for judging the selected landscapes were the evaluation, size and density factors. According to residents' opinions, the river has to be conserved in a natural way with a wide space on riverside where people can enjoy rural-woody landscape. Also the construction of recreational facilities has to be designed in a simple, modest and natural way which allows contact with water. This research seeks to evaluate residents' attitudes towards the landscape and aim that local planning authorities could consider these results in their development policies

歴史的景観に対する住民の態度と視覚的選好に関する研究 : 神戸市西区のアーバン・フリンジを事例として

In this study, resident groups from an urban and a rural district, both located in the western urban fringe of Kobe City were interviewed in order to evaluate their attitudes towards the historic landscape of Taisan-ji temple. The residents' interests and their activities in this area were asked by a questionnaire and an aerial-photograph was used to visualize their favorite and hateful places. In a previous study, this area was assessed by residents as the most favorite place in the region, which should be protected. From the results, each group possesses different attitudes which are mostly based on their everyday living experiences and cultural values. Through a comparative analysis of preferences the main attitudes were defined into the "native" and "visitor" points of views. To improve this area, the Ikawa river should be restored by its own natural features and a stroll path should connect a desired hillside forest park with a parking lot.神戸市西区の互いに隣接する市街化区域と市街化調整区域 (農村地区) の住民を対象として太山寺の歴史的景観に対する意識と選好を評価する目的でインタビューを行った。前回の研究で住民はこの場所をすべての地域の中で最も気に入った場所として保存が必要と評価した。今回は, 3つの住民グループにこの地区についての関心とそこでの生活に関して質問を行うととともに, 航空写真を用いて, その地区での住民の最も好きな場所と最も嫌いな場所の選定を行った。その結果, 各グループは異なった意識を示した。これらの意識は, 日常生活における経験と文化的背景によって異なり, 「地元の人」の意識と「訪門者」の意識とみなす事ができた。この地区を改善するために伊川をはその固有の自然的特徴を活かして修復し, 駐車場と森林公園を連結した遊歩道をつくることが必要と考えられた

視覚的手法を用いた区画整理事業に対する住民の選好について : 神戸市のアーバン・フリンジを事例として

神戸市西区伊川谷の前開地区は, 神戸市のアーバン・フリンジに位置しているが, 急速に開発が進展し, 農村の土地利用と景観が変化してきた。このような都市近接農村では, 自治体も住民参加による地域計画を実施しようとしている。そこで, 調和のとれた地域計画を作成するための住民の意見を知ることが必要になってきた。このような点をふまえ, 主として航空写真を用いて景観変化に関する住民の選好を調査し, 報告した。今回は, さらにこの選好内容を具体的かつ視覚的に把握するため, 同地区を対象に, 今後展開される予定の区画整理事業等による開発計画を検討し, そのいくつかの例のスケッチとコンピューター・シミュレーションを用いて住民の選好を調査した。結果として, 住民の景観に対する選好は開発と保全の間で多様な展開を見せたが, とくに低密度の開発と河川や道路などの帯状緑化が, 農村集落景観の保全計画にとって不可欠な要素であることが明らかとなった。The Zenkai district is a rural area located in the urban fringe of Kobe City, that recently has been rapidly developed. The city planning trend has introduced drastic changes in the existing landscape where conflicts in land-use are remarkables. Therefore, the local authority is promoting resident's participation to rural planning. In a previous study, 5) concerning the selection of different types of development to be carried out in the region, an aerial-photograph was used and the result of the opinion of residents was reported at that time. The objective of the present research is to visually understand the contents of that selection. Therefore a site research was performed and the preferences of residents regarding the type of development that should be carried out in areas around the Ikawadani station was studied through the use of visual simulation procedures. As a result, a wide variety of answers were obtained concerning the concepts of development and conservation. The necessity of a low density development with buildings that maintain an architectural relationship with the old existing communities, was specifically determined. Furthermore, green zones between new structures and along the Ikawa river is an important resource that should be promoted in order to achieve this integration

景観保全のための視覚的評価に関する研究 - 神戸市西区のアーバン・フリンジを事例として

京都大学0048新制・課程博士博士(農学)甲第6911号農博第929号新制||農||741(附属図書館)学位論文||H9||N3035(農学部図書室)16028UT51-97-H295京都大学大学院農学研究科科林学専攻(主査)教授 吉田 博宣, 教授 小橋 澄治, 教授 高橋 強学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDA