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排序方式: 共有334条查询结果,搜索用时 15 毫秒
61.
Lin Hongkuan Tekes Ayse Tekes Coskun 《Journal of Mechanical Science and Technology》2020,34(2):555-563
Journal of Mechanical Science and Technology - In this study, we present the design and development of a compliant multi-link hopping mechanism actuated by a single DC motor. Mechanism consists of... 相似文献
62.
Atmospheric concentrations, dry deposition and air-soil exchange of polycyclic aromatic hydrocarbons (PAHs) in an industrial region in Turkey 总被引:6,自引:0,他引:6
Concurrent ambient air and dry deposition samples were collected during two sampling periods at the Aliaga industrial region in Izmir, Turkey. Sigma 15-PAH (particulate+gas) concentrations ranged between 7.3 and 44.8 ng m(-3) (average+/-S.D., 25.2+/-8.8 ng m(-3)) and 10.2-71.9 ng m(-3) (44.1+/-16.6 ng m(-3)) in summer and winter, respectively. Winter/summer individual ambient PAH concentration ratios ranged between 0.8 (acenaphthene) and 6.6 (benz[a]anthracene) indicating that wintertime concentrations were affected by residential heating emissions. In contrast to the ambient concentrations, summation operator(15)-PAH particle dry deposition fluxes were higher in summer (5792+/-3516 ng m(-2)day(-1), average+/-S.D.) than in winter (2650+/-1829 ng m(-2)day(-1)), probably due to large particles from enhanced re-suspension of polluted soil particles and road dust. Average overall dry deposition velocity of PAHs calculated using the dry deposition fluxes and particle-phase concentrations was 2.9+/-3.5 cm s(-1). summation operator(15)-PAH concentrations in soils taken from 50 points in the area ranged between 11 and 4628 microg kg(-1) in dry weight. The spatial distribution of these concentrations indicated that the urban Aliaga, steel plants, the petroleum refinery, and the petrochemical plant are the major Sigma 15-PAH sources in the area. Fugacity calculations in air and soil showed that the soil acts as a secondary source to the atmosphere for low molecular weight PAHs in summer and as a sink for the higher molecular weight ones in summer and winter. 相似文献
63.
A multifunctional sandwich type wound dressing was designed in which two types of microspheres, one to alleviate the pain (ibuprofen) and the other to protect the wound from infections (Gentamicin or Ciprofloxacin), were embedded into bilayer chitosan sponge. pH of the wound increases from acidic (pH ~ 5) to basic (pH ~ 8) via infection, so pH-dependent antibiotic release system was designed using gelatin B microspheres to respond to increasing pH. Ibuprofen release from chitosan microspheres, on the other hand, was pH-independent not to intervene with pain management in changing pH conditions. Crosslinking with glutaraldehyde (GA) affected both release profile and size distribution of microspheres and 2.5% GA was chosen to obtain pH-responsive gelatin microspheres with narrow size distribution (80% of microspheres in between 15 and 25 μm). The final system was found to be effective against both Staphylococcus aureus and Escherichia coli and changing pH seemed to affect the antimicrobial agent delivery as desired. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48252. 相似文献
64.
Mean-square dipole moments for styrene/4-vinylpyridine (S4VP) random copolymers were determined at five different temperatures, 25–60°C, in 1,4-dioxane solution. The dipole moment behaviour was examined with respect to the increase in mole fraction of the polar monomer, 4-vinylpyridine (4VP), in the copolymer. The behaviour observed was different from the general behaviour of similar copolymers. The temperature coefficient of the dipole moment ratio was found to be zero, within experimental error, in the temperature interval 25–60°C. 相似文献
65.
Ayse Alaylioglu 《Computers & Structures》1988,29(6):1119-1130
Procreation of the C1 continuous displacement FE efficient vibration model, which can be attained by exploiting the unparalleled conciseness and cost-objectiveness of a computer automated exact analytical integrator, is considered. The proposed Kirchhoff-conforming, rectangular four dof/node plate FE vibration simulator is demonstrated to achieve high accuracy with low CPU expenditure in a straightforward and systematic framework without calling for any ad hoc mechanisms. Due to idiosyncrasies of the formulation, the code has the potential for providing high-speed computational power to aid accurate and reliable identification of a wide spectrum of vibration modes that faithfully captures the physical behavior of thin plates, frequently encountered in real-life engineering applications. 相似文献
66.
Ayse Erdem Senatalar Enis Kadioglu Mustafa Tolay Keith D. Bartle colin E. Snape Norman Taylor 《Fuel》1985,64(12):1748-1753
The yields and the nature of the products from the solvent extraction of Avgamasya asphaltite of SE Turkey with benzene and toluene under Soxhlet, subcritical (up to 292 °C) and supercritical (350–450 °C) conditions are reported. The subcritical yield increases with temperature but also depends on pressure; the extra yield is mainly of asphaltenes. The 350 °C supercritical toluene extract shows little evidence of thermal degradation and is similar in yield and chemical nature to that obtained under subcritical conditions except that it contains more pentane-soluble material. At 450 °C the yield is increased and a number of pyrolytic effects are observed, including reduction in molecular mass, loss of heterocyclic and alkyl groups and the presence of toluene decomposition products. 相似文献
67.
Poly(2‐hydroxyethyl methacrylate)/boric acid composite hydrogel as soft contact lens material: Thermal,optical, rheological,and enhanced antibacterial properties 下载免费PDF全文
Ahmet Ulu Sevgi Balcioglu Emre Birhanli Ayse Sarimeseli Rukiye Keskin Suleyman Koytepe Burhan Ates 《应用聚合物科学杂志》2018,135(35)
The present work proposes to fabricate a composite hydrogel material that well characterized, transparent, biocompatible, and self‐antibacterial as potential soft contact lens material. For this purpose, poly(2‐hydroxyethyl methacrylate) (PHEMA)/boric acid (BA) composite hydrogels were successfully prepared by chemical crosslinking with BA through in situ polymerization using different BA ratios between 1 and 10% w/w. Afterward, the compositions, thermal stability, transparence, oxygen permeability, water uptake capacity, swelling ratio as well as morphological and rheological properties, in vitro degradability, in vitro cytotoxicity, and antibacterial properties of the all prepared materials were analyzed using a series of different techniques. The thermal stability, hydrophilicity, water uptake, oxygen permeability gradually increased depending ratio of BA, which is desirable for biomaterial. While the transparence and refractive index decreased, the composite hydrogels, except for BA content of 10 wt %, maintained enough transparency to be used for contact lens. In addition, PHEMA/BA composite hydrogels exhibited good cytocompatibility (PHEMA‐1%BA and PHEMA‐3%BA) and excellent antibacterial activity against Gram‐positive (Staphylococcus aureus and Enterococcus faecium) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrated that the obtained PHEMA/BA composite hydrogels could be considered as self‐antibacterial contact lens and a potential composite biomaterial for other applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46575. 相似文献
68.
David R. Large Gary Burnett Elizabeth Crundall Editha van Loon Ayse L. Eren Lee Skrypchuk 《International journal of human-computer interaction》2018,34(1):1-14
Touchscreen human–machine interfaces (HMIs) are commonly employed as the primary control interface and touch-point of vehicles. However, there has been very little theoretical work to model the demand associated with such devices in the automotive domain. Instead, touchscreen HMIs intended for deployment within vehicles tend to undergo time-consuming and expensive empirical testing and user trials, typically requiring fully functioning prototypes, test rigs, and extensive experimental protocols. While such testing is invaluable and must remain within the normal design/development cycle, there are clear benefits, both fiscal and practical, to the theoretical modeling of human performance. We describe the development of a preliminary model of human performance that makes a priori predictions of the visual demand (total glance time, number of glances, and mean glance duration) elicited by in-vehicle touchscreen HMI designs, when used concurrently with driving. The model incorporates information theoretic components based on Hick–Hyman Law decision/search time and Fitts’ Law pointing time and considers anticipation afforded by structuring and repeated exposure to an interface. Encouraging validation results, obtained by applying the model to a real-world prototype touchscreen HMI, suggest that it may provide an effective design and evaluation tool, capable of making valuable predictions regarding the limits of visual demand/performance associated with in-vehicle HMIs, much earlier in the design cycle than traditional design evaluation techniques. Further validation work is required to explore the behavior associated with more complex tasks requiring multiple screen interactions, as well as other HMI design elements and interaction techniques. Results are discussed in the context of facilitating the design of in-vehicle touchscreen HMI to minimize visual demand. 相似文献
69.
The use of fuzzy set theory in the analytic hierarchy process (AHP) has gained popularity in recent years as part of the multiple criteria decision-making (MCDM) process to more realistically reflect human judgment. However, due to the nature of fuzzy calculations, this situation imposes more computational load. The aim of this study is to propose methods for obtaining accurate weights from fuzzy pairwise comparison matrices with the least amount of computational load possible. In this context, two different fuzzy AHP (FAHP) methods based on fuzzy numbers ranking methods have been proposed and these proposed methods are compared with commonly accepted FAHP methods. Magnitude-based fuzzy AHP (MFAHP), which is one of the proposed methods, has outperformed all other methods according to accurate weight and computational load. Although the other proposed method, called the total difference-based fuzzy AHP (TDFAHP), gave better results than the frequently used Chang's fuzzy extent analysis method, it could not produce more accurate weight results than many other methods in general. But performance analysis shows that it is as good as the MFAHP in terms of computational load. 相似文献
70.
International Journal of Steel Structures - Having knowledge of dynamic properties named as natural frequency and mode shapes during the design process is important to determine proper design... 相似文献