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101.
This study intended to improve the performance of the beta‐type Stirling engine, being developed by the authors for solar energy and low‐grade heat sources, by means of displacer surface treatments. Three different displacers were manufactured and tested where one of them was without any surface treatment, other was zirconium coated with 0.15 mm thickness, and the other was helically knurled with 0.30 mm track depth. Because of good thermo‐physical properties, helium was used as the working fluid. The heat was supplied by an LPG burner. Tests were conducted at 360±10°C hot end temperature. The highest engine power was obtained with knurled displacer as 250 W at 545 rpm speed and corresponding to this power 4.38 Nm torque was obtained. This was followed by coated and smooth displacers. Power increments provided by the knurled displacer are 40 and 60% compared with the zirconium‐coated and untreated displacers. Increments of knurled displacer's torque compared with that of coated and untreated displacers are 13 and 30%, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
102.
Oğuzhan Hasançebi Serdar Çarbaş Mehmet Polat Saka 《Structural and Multidisciplinary Optimization》2010,41(2):189-203
This study aims at improving the performance of simulated annealing (SA) search technique in real-size structural optimization
applications with practical design considerations. It is noted that a standard SA algorithm usually fails to produce acceptable
solutions to such problems associated with its poor convergence characteristics and incongruity with theoretical considerations.
In the paper novel approaches are developed and incorporated into the standard SA algorithm to eliminate the observed drawbacks
of the technique. The performance of the resulting (improved) algorithm is investigated in conjunction with two numerical
examples (a 304-member braced planar steel frame, and 132-member unbraced space steel frame) designed according to provisions
of the Allowable Stress Design (ASD) specification. In both examples, curves showing the variation of average acceptance probability
parameter in standard and improved algorithms are plotted to verify usefulness and robustness of the integrated approaches. 相似文献
103.
Serdar Yaman Ayşegül Ersoy-Mericboyu Sadriye Küçükbayrak 《Petroleum Science and Technology》2013,31(1):49-58
Abstract A number of methods have been developed which are used to remove the sulphur present in coal before combustion. The physical removal of pyritic sulphur by coal cleaning has been commercial practice for a number of years, but these methods do not remove organically bound sulphur, they can be applied effectively only to a limited number of coals. However, the removal of both pyritic and organically bound sulphur from coal can be effectively achieved by applying the chemical desulphurization methods. This paper gives a general review on the chemical desulphurization studies, including carbonization in different atmospheres, air oxidation, wet oxidation, Meyers Process, chlorination and extraction with the solutions of NaOH, CuCl2 and C2H5OH, which were carried out using different Turkish lignites. 相似文献
104.
In this study, we analyze a decentralized supply chain with a single retailer and a single manufacturer where the retailer sells multiple products in a single period. The products differ in terms of a limited number of features only. The retailer places initial orders based on preliminary demand forecasts at the beginning of the period and has an opportunity to modify its initial order after receiving perfect demand information. However, the final orders of the retailer are constrained by its initial orders. The manufacturer has two options for procurement. The first procurement option is regular delivery at the beginning of the period, after the initial orders of the retailer. The next one is expedited delivery, after the updated orders are received. In this setting, our objective is to characterize the optimal policies for the retailer and the manufacturer, and assess the benefits of flexibility. 相似文献
105.
Filiz Kuralay Arzum Erdem Serdar Abacı Haluk Özyörük Attila Yıldız 《Journal of Applied Electrochemistry》2010,40(11):2039-2050
Poly(vinylferrocenium) (PVF+) modified gold (Au) electrode was developed in this study for the electrochemical sensing of deoxyribonucleic acid (DNA)
hybridization based on the oxidation signals of polymer and guanine, and also for the electrochemical investigation of interaction
of anticancer drug, mitomycin C (MC) and DNA immobilized onto PVF+ modified Au electrode. PVF+ modified Au electrode was prepared by electrooxidation of poly(vinylferrocene) PVF at +0.7 V versus Ag/AgCl reference electrode.
The polymer modified electrode and DNA immobilized polymer modified electrode were characterized by X-ray photoelectron (XPS),
Fourier transform infrared-attenuated total reflentance (FTIR-ATR) and alternating current (AC) impedance spectroscopy. For
application studies, differential pulse voltammetry (DPV) technique was used. 相似文献
106.
Hüseyin Yiğiter Serdar Aydın Halit Yazıcı Mert Yücel Yardımcı 《Composites Part B》2012,43(8):2907-2914
The possibility of producing a reactive powder concrete (RPC) with low cement content was aimed in the scope of this study. Cement was replaced with class-C fly ash (FA) up to 60% for this purpose. Three different curing conditions (standard water curing, autoclave curing and steam curing) were applied to specimens. Two series of RPC composites were prepared with bauxite and granite aggregates. Mechanical properties such as compressive strength, splitting tensile strength, flexural strength and fracture energy of composites were investigated. Test results showed that, compressive strength of 200 MPa can be reached with low cement by using high-volume fly ash. Thermally treated specimens showed compressive strength beyond 250 MPa and high volume fly ash RPC have superior performance. Furthermore, compressive strength values reached up to 400 MPa with external pressure application during setting and hardening stages. 相似文献
107.
Atilla-Gokcumen GE Williams DS Bregman H Pagano N Meggers E 《Chembiochem : a European journal of chemical biology》2006,7(9):1443-1450
A chiral second-generation organoruthenium half-sandwich compound is disclosed that shows a remarkable selectivity and cellular potency for the inhibition of glycogen synthase kinase 3 (GSK-3). The selectivity was evaluated against a panel of 57 protein kinases, in which no other kinase was inhibited to the same extent, with a selectivity window of at least tenfold to more than 1000-fold at 100 microM ATP. Furthermore, a comparison with organic GSK-3 inhibitors demonstrated the superior cellular activity of this ruthenium compound: wnt signaling was fully induced at concentrations down to 30 nM. For comparison, the well-established organic GSK-3 inhibitors 6-bromoindirubin-3'-oxime (BIO) and kenpaullone activate the wnt pathway at concentrations that are higher by around 30-fold and 100-fold, respectively. The treatment of zebrafish embryos with the organometallic inhibitor resulted in a phenotype that is typical for the inhibition of GSK-3. No phenotypic change was observed with the mirror-imaged ruthenium complex. The latter does not, in fact, show any of the pharmacological properties for the inhibition of GSK-3. Overall, these results demonstrate the potential usefulness of organometallic compounds as molecular probes in cultured cells and whole organisms. 相似文献
108.
109.
Robert J. Pieper Abdullah Ekin Dean C. Webster Franck Cassé James A. Callow Maureen E. Callow 《Journal of Coatings Technology and Research》2007,4(4):453-461
The effect of acrylic polyol composition on the properties of crosslinked siloxane-polyurethane coatings was explored. An
acrylic polyol library was synthesized using batch solution polymerization and characterized using high-throughput gel permeation
chromatography (Rapid-GPC) and differential scanning calorimetry (DSC). Siloxane-polyurethane coatings were prepared from
3-aminopropyl-terminated poly(dimethylsiloxane) (PDMS), the acrylic polyols and a polyisocyanate crosslinker. The siloxane-acrylic-polyurethane
coatings were tested for mechanical and physical properties. The siloxane-polyurethane coatings had a systematic variation
in glass transition temperature and had water contact angles ranging from 95° to 100°. Many of the coatings also showed a
low-force of release in the pseudo-barnacle pull-off adhesion test. Performance testing of the fouling-release properties
of the siloxane-polyurethane coatings on array panels with algae, namely the diatom Navicula and sporelings (young plants) of the green seaweed Ulva was also conducted.
Presented at the 2006 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans,
LA, on November 1–3, 2006. 相似文献
110.
In this paper, optimal control of linear time-invariant (LTI) systems over unreliable communication links is studied. The motivation of the problem comes from growing applications that demand remote control of objects over Internet-type or wireless networks where links are prone to failure. Depending on the availability of acknowledgment (ACK) signals, two different types of networking protocols are considered. Under a TCP structure, existence of ACK signals is assumed, unlike the UDP structure where no ACK packets are present. The objective here is to mean-square (m.s.) stabilize the system while minimizing a quadratic performance criterion when the information flow between the controller and the plant is disrupted due to link failures, or packet losses. Sufficient conditions for the existence of stabilizing optimal controllers are derived. 相似文献