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Tsinghua Science and Technology 2004年第5期9卷 527-545页

作者： muammer ko S. M. Wu Manufacturing Research Center Department of Mechanical EngineeringCollege of Engineering University of Michigan Ann Arbor MI 48109 USA

The tube hydroforming process (THF) has recently found a wide application opportunity in the automotive industry, and is of increasing interest to other industries as well. The increased interest stems from the fact that, through the THF process, manufacturers are able to produce complex, consolidated, lightweight parts with reduced number of post-processing than through alternative metal forming techniques. In order to fully realize the benefits of this technology, various aspects have been under investigation in academia and industry world-wide. In this paper, effect of loading path, incoming material variation, and lu- brication on the robustness of the hydroforming process and final part specifications are summarized based on previous experimental and computational work. In addition, the simulation of hydroforming and examples are presented in comparison with experimental findings. Briefly, results emphasized the importance of the loading path design whereas material variation within the experimentally tested range was not found to be significantly effective on the final part specifications. Selection of a lubricant for hydroforming of a frame rail part was presented demonstrating several aspects of lubrication selection methodology. Results of friction experiments show that only thickness, axial feeding, and force measurements are good indications of lubri- cant performance as these are found to be strongly discriminative.

关键词： hydroforming friction tribology lubrication material variation

Additive manufacturing of biodegradable magnesium implants and scaffolds: Review of the recent advances and research trends

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Journal of Magnesium and Alloys 2021年第2期9卷 392-415页

作者： Nurettin Sezer Zafer Evis muammer koç Division of Sustainable Development College of Science and EngineeringHamad Bin Khalifa UniversityQatar FoundationEducation CityDohaQatar Engineering Sciences Middle East Technical UniversityPO Box 06800AnkaraTurkey University of Karabük Turkey

Synthetic grafting needs improvements to eliminate secondary surgeries for the removal of implants after healing of the defected *** scaffolds are engineered to serve as temporary templates,which support the affected tissue and gradually degrade through the healing *** mechanical function to withstand the anatomic loading conditions,scaffolds should also provide a decent biological function for the diffusion of nutrients and oxygen to the cells,and excretion of the wastes from the cells to promote the new tissue growth and ***,the degradation byproducts of the scaffolds should be safe to the human *** of such multifunctional scaffolds requires selection of the right material,design,and manufacturing *** has been recognized as the prominent biodegradable metal with regards to its mechanical properties matching to that of human bone,degradability in the body fluid,and its ability to stimulate new tissue *** with intricate porous structures can be designed according to the patient-specific anatomic data using computer aided *** manufacturing(AM)is the right method to materialize these models rapidly with reasonably acceptable range of dimensional ***,the recent research trend is to develop ideal scaffolds using biodegradable Mg through AM *** review compiles and discusses the available literature on the AM of biodegradable Mg parts from the viewpoints of material compositions,process conditions,formation quality,dimensional accuracy,microstructure,biodegradation,and mechanical *** current achievements are summarized together,and future research directions are identified to promote clinical applications of biodegradable Mg through the advancement of AM.

关键词： Magnesium Alloy Implant Tissue scaffold Additive manufacturing Biodegradation

Review of magnesium-based biomaterials and their applications

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Journal of Magnesium and Alloys 2018年第1期6卷 23-43页

作者： Nurettin Sezer Zafer Evis Said Murat Kayhan Aydin Tahmasebifar muammer koça Sustainable Development Divison Hamad Bin Khalifa UniversityQatar FoundationEducation CityDohaQatar Engineering Sciences Middle East Technical UniversityPO Box 06800AnkaraTurkey

In biomedical applications,the conventionally used metallic materials,including stainless steel,Co-based alloys and Ti alloys,often times exhibit unsatisfactory results such as stress shielding and metal ion *** surgical operation(s)usually become inevitable to prevent long term exposure of body with the toxic implant *** metallic biomaterials are being revolutionized with the development of biodegradable materials including several metals,alloys,and metallic *** such,the nature of metallic biomaterials are transformed from the bioinert to bioactive and multi-biofunctional(anti-bacterial,anti-proliferation,anti-cancer,etc.).Magnesium-based biomaterials are candidates to be used as new generation biodegradable ***(Mg)can dissolve in body fluid that means the implanted Mg can degrade during healing process,and if the degradation is controlled it would leave no debris after the completion of ***,the need for secondary surgical operation(s)for the implant removal could be *** its biocompatibility,the inherent mechanical properties of Mg are very similar to those of human *** have been working on synthesis and characterization of Mg-based biomaterials with a variety of composition in order to control the degradation rate of Mg since uncontrolled degradation could result in loss of mechanical integrity,metal contamination in the body and intolerable hydrogen evolution by *** was observed that the applied methods of synthesis and the choice of components affect the characteristics and performance of the Mg-based *** have synthesized many Mg-based materials through several synthesis routes and investigated their mechanical properties,biocompatibility and degradation behavior through in vitro,in vivo and in silico *** paper is a comprehensive review that compiles,analyses and critically discusses the recent literature on the important aspects of Mg-based biom

关键词： Mg-based biomaterials Mechanical properties Implant Biomedical applications Biodegradation

Dissolution behavior of Caldag lateritic nickel ore subjected to a sequential organic acid leaching method

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1131-1140页

作者： Sait Kursunoglu muammer Kaya Department of Mining Engineering Eskisehir Osmangazi University

The dissolution behavior of Caldag lateritic nickel ore subjected to a sequential organic acid leaching method was investigated. The effects of the type of organic acid, acid concentration, leaching time, and leaching temperature on the lateritic nickel ore were examined. Organic acids were used individually prior to sequential leaching. Citric acid was more effective than the other two acids for the selective leaching of nickel and cobalt. An increase in the citric acid concentration negligibly affected the dissolution of the metals, whereas temperature exhibited a strong beneficial effect. Oxalic acid was determined to be the most appropriate organic acid for the second leaching step. After 8 h（4 h ＋ 4 h） of leaching with organic acids（0.5 M citric ＋ 0.5 M oxalic） in sequence at 90°C, 89.63% Ni, 82.89% Co, and 69.63% Fe were leached from the lateritic nickel ore. A sequential citric ＋ oxalic acid leaching method could represent a viable alternative for the dissolution of metals from lateritic nickel ore.

关键词： laterite leaching citric acid oxalic acid dissolution

Parametric analysis of warm forming of aluminum blanks with FEA and DOE

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中国有色金属学会会刊：英文版 2006年第2期16卷 267-273页

作者：陈鹏林忠钦陈关龙 K. muammer School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200030 China Department of Mechanical Engineering Univ ersity of Michigan Ann Arbor Michigan USA

The effect of temperature distribution on warm forming performance was investigated for 5083-O (Al-Mg) sheet metal blanks. Combined isothermal/non-isothermal FEA with design of experiments tools were used to predict appropriate warm forming temperature conditions for deep drawing and two-dimensional stamping cases. In the investigated temperature range of 25?250 ℃, the formability of Al-5083 alloy is found to be greatly dependent on the temperature distribution of the die and punch. To achieve increased degrees of forming, different temperature levels should be assigned to the corner and body of the die and punch. And the optimal temperature distributions for warm deep drawing and warm two-dimensional stamping are not identical.

关键词：热成型铝合金有限元 FEA DOE

Focal therapy for localized prostate cancer:is there a “middle ground” between active surveillance and definitive treatment?

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Asian Journal of Andrology 2019年第1期21卷 37-44页

作者： Cihan H Demirel muammer Altok John W Davis Department of Urology The University of Texas MD Anderson Cancer CenterHoustonTexas 77030USA.

In recent years,it has come a long way in the diagnosis,treatment,and follow-up of prostate *** this,it was argued that definitive treatments could cause overtreatment,particularly in the very low,low,and favorable risk *** alternative treatment and follow-up methods are being considered for this group of patients,active surveillance is seen as a good alternative for patients with very low and low-risk groups in this ***,it has become necessary to find other alternatives for patients in the favorable risk group or patients who cannot adopt active *** the light of technological developments,the concept of focal therapy was introduced with the intensification of research to treat only the lesioned area instead of treating the entire organ for prostate lesions though there are not many publications about many of them *** to the initial results,it was understood that the results could be good if the appropriate focal therapy technique was applied to the appropriate ***,focal therapies have begun to find their"middle ground"place between definitive therapies and active follow-up.

关键词： focal therapy multiparametric magnetic resonance imaging prostate biopsy prostate cancer prostatic neoplasms

Artificial neural network models predicting the leaf area index:a case study in pure even-aged Crimean pine forests from Turkey

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Forest Ecosystems 2018年第4期5卷 400-411页

作者： ilker Ercanli Alkan Gunlu muammer Senyurt Sedat Keles Faculty of Forestry Cankin Karatekin University18200 CankiriTurkey

Background: Leaf Area Index(LAI) is an important parameter used in monitoring and modeling of forest ecosystems. The aim of this study was to evaluate performance of the artificial neural network(ANN) models to predict the LAI by comparing the regression analysis models as the classical method in these pure and even-aged Crimean pine forest ***: One hundred eight temporary sample plots were collected from Crimean pine forest stands to estimate stand parameters. Each sample plot was imaged with hemispherical photographs to detect the LAI. The partial correlation analysis was used to assess the relationships between the stand LAI values and stand parameters, and the multivariate linear regression analysis was used to predict the LAI from stand parameters. Different artificial neural network models comprising different number of neuron and transfer functions were trained and used to predict the LAI of forest ***: The correlation coefficients between LAI and stand parameters(stand number of trees, basal area, the quadratic mean diameter, stand density and stand age) were significant at the level of 0.01. The stand age, number of trees, site index, and basal area were independent parameters in the most successful regression model predicted LAI values using stand parameters(R_(adj)~2=0.5431). As corresponding method to predict the interactions between the stand LAI values and stand parameters, the neural network architecture based on the RBF 4-19-1 with Gaussian activation function in hidden layer and the identity activation function in output layer performed better in predicting LAI(SSE(12.1040), MSE(0.1223), RMSE(0.3497), AIC(0.1040), BIC(-77.7310) and R^2(0.6392)) compared to the other studied ***: The ANN outperformed the multivariate regression techniques in predicting LAI from stand parameters. The ANN models, developed in this study, may aid in making forest management planning in study forest stands.

关键词： Leaf area index Multivariate linear regression model Artificial neural network modeling Crimean pine Stand parameters

Effect of cryogenic cooling in milling process of AISI 304 stainless steel

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Transactions of Nonferrous Metals Society of China 2011年第1期21卷 72-79页

作者： muammer NALBANT Yakup YILDIZ Faculty of Technical Education Gazi University Department of Machine Education Gazi University

The effects of cryogenic cooling on cutting forces in the milling process of AISI 304 stainless steel were investigated *** cooling was achieved by spraying liquid nitrogen to tool,chips and material interfaces using a pipe with an internal diameter of 1 mm;the flow rate of liquid nitrogen was 5.2 L/min;two cutting directions（climbing and conventional milling）,two machining conditions（dry and cryogenic cooling） and four cutting speeds（80,120,160 and 200 m/min） were used in the milling *** cooling and cutting speed are found to be effective on cutting *** forces and torque in cryogenic milling are higher than those in dry *** force is increased as the cutting speed is *** fritter around insert nose radius is the main problem of climb milling method in cryogenic cooling at low cutting speeds.

关键词： cryogenic cooling AISI 304 cutting force tool frittering

Recovery of zinc and lead from Yahyali non-sulphide flotation tailing by sequential acidic and sodium hydroxide leaching in the presence of potassium sodium tartrate

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Transactions of Nonferrous Metals Society of China 2020年第12期30卷 3367-3378页

作者： Sait KURSUNOGLU Soner TOP muammer KAYA Department of Materials Science&Nanotechnology Engineering Abdullah Gul UniversityKayseri 38100Turkey Division of Mineral Processing Department of Mining EngineeringEskisehir Osmangazi UniversityEskisehir 26480Turkey

The recovery of zinc and lead from Yahyali non-sulphide flotation tailing using sulfuric acid followed by sodium hydroxide leaching in the presence of potassium sodium tartrate was experimentally *** the acidic leaching stage,the effects of pH,solid-to-liquid ratio and temperature on the dissolution of zinc from the tailing were explored.82.3%Zn dissolution was achieved at a pH of 2,a temperature of 40°C,a solid-to-liquid ratio of 20%and a leaching time of 2 h,whereas the iron and lead dissolutions were determined to be less than 0.5%.The sulfuric acid consumption was found to be 110.6 kg/t(dry tailing).The leaching temperature had no beneficial effect on the dissolution of zinc from the *** acidic leach solution was subjected to an electrowinning *** cathode product consisted of 99.8%Zn and 0.15%*** the alkaline leaching stage,the Pb dissolution increased slightly in the presence of potassium sodium *** than 60%of Pb was taken into the leach solution when the leaching temperature increased from 40 to 80°*** final leach residue was analyzed by XRD and *** XRD results indicated that the major peaks originated from the goethite and quartz while minor peaks stem from smithsonite and *** XRF analysis demonstrated that the residue contained 70.3%iron *** on the sequential leaching experiments,the zinc and lead were excellently depleted from the flotation tailing,leaving a considerable amount of iron in the final residue.

关键词： zinc lead flotation tailing sequential leach

Dissolution of lateritic nickel ore using ascorbic acid as synergistic reagent in sulphuric acid solution

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Transactions of Nonferrous Metals Society of China 2018年第8期28卷 1652-1659页

作者： Sait KURSUNOGLU Zela Tanlega ICHLAS muammer KAYA Department of Materials Science & nanotechnology Engineering Abdullah Gul University Kayseri 38100 Turkey Department of Metallurgical Engineering Faculty of Mining and petroleum Engineering Institut teknologi Bandung Bandung 40132 Indonesia Division of Mineral processing Department of Mining Engineering eskisehir Osmangazi University Eskisetfir 26480 Turkey

The dissolution of nickel and cobalt from Caldag lateritic nickel ore using the combination of sulphuric and ascorbic acids was investigated. The use of other organic acids, namely citric, maleic and stearic acids, as synergistic reagents was studied for comparison. The results revealed that the use of ascorbic and citric acids markedly improved the dissolution of cobalt compared to the other two organic acids that only showed slight synergistic effect on the leaching rate. In terms of nickel dissolution, ascorbic acid is the most effective synergist, followed by citric, maleic and stearic acids in descending order. Under the most optimized conditions found in this study, i.e., using 1 mol/L of sulphuric acid with the presence of 4 g/L of ascorbic acid at 80 ℃and solid-to-liquid ratio of 1/10, more than 99% and 98% leaching rates of cobalt and nickel, respectively, can be achieved within 4 h of leaching. In addition, the leaching performance is relatively insensitive to the change of ascorbic acid concentration from 2 to 4 g/L which is highly desirable from operational perspective.

关键词： laterite ore Caldag lateritic nickel ore synergistic reagent ascorbic acid nickel cobalt