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排序方式: 共有176条查询结果,搜索用时 31 毫秒
51.
Cun Rong Li Xiao Long Chen Bhaba R Sarker Hui Zhi Yi 《The Journal of the Operational Research Society》2015,66(12):2050-2060
For high-value added products, machining tools’ lifespan significantly influences the quantity of procurement in machining process. Preemption of tools from the workpiece while processing is continuing is sometime beneficial to safeguard the product from the damage due to tool failure or its malfunction. Also an early discard of a tool is costly for the manufacturing operation. Therefore an optimal strategy for the tool life is sought here to determine the maximum allowable tool lifespan to preempt from the workpiece and to have an appropriate amount of tool stock in the crib to ascertain the proper running of the production schedule and tool inventory. Therefore, an impact of the machining tool lifespan on the production-inventory policy of the system is investigated in this paper. An integrated lifespan related inventory model for machining tools is developed to meet the responding accurate requirement of procurement and inventory. Two numerical examples are presented to illustrate the integrated model. The results show that the practical lifespan adoption of machining tools has significant impact on the whole quantity of procurement, and eventually influences the coordinating economic decision making. 相似文献
52.
A. J. Saleh Ahammad Subrata Sarker Md Aminur Rahman Jae‐Joon Lee 《Electroanalysis》2010,22(6):694-700
A selective and very simple electrochemical method, based on anodization of a glassy carbon electrode (GCE), was developed for the simultaneous detection of hydroquinone (HQ) and catechol (CT). It was found that the activated GCE showed an excellent catalytic behavior and enhanced reversibility towards the oxidation of both HQ and CT. The redox responses from the mixture of HQ and CT were easily resolved at an activated GCE. The detection limits for HQ and CT were calculated to be 0.16 and 0.11 μM, respectively. The activated GCE was successfully examined for real sample analysis with tap water and it showed a stable and reliable recovery data. 相似文献
53.
A good measure is necessary to evaluate the goodness of grouping in cellular manufacturing. For simple group technology (GT) problems, there are some grouping measures available, the most cited ones are grouping efficiency and grouping efficacy. A grouping measure, which considers alternative routings, is not available for the generalised GT problems. In this paper a new measure called alternative routing grouping (ARG) efficiency is proposed and its desirable properties are derived. Not only can this alternative routing grouping efficiency be used in the generalised GT problems, but it can also be used in the simple GT problems. The computation of the alternative routing grouping efficiency is illustrated with examples, and results of empirical tests on a set of known problems are also reported in this paper. The alternative routing grouping efficiency is extended to the simple GT measures. Grouping efficiency suffers from a weak discriminating capability and grouping efficacy has relatively a better discriminating capability. It is proved that the ARG efficiency has better discriminating capability than the existing measures, and this measure can evaluate the effectiveness of grouping in both simple and generalised cell formation problems with alternative process plans. 相似文献
54.
Y. Kumarasamy M. Byres P. J. Cox A. Delazar M. Jaspars L. Nahar M. Shoeb S. D. Sarker 《Chemistry of Natural Compounds》2004,40(2):122-128
Preparative reversed-phase HPLC analysis of a methanol extract of the seeds of Alliaria petiolata afforded fourflavone 6-C-glycosides: isoorientin, swertiajaponin, swertisin and isoscoparin-2--D-glucopyranoside. The molecular structures were elucidated by UV, ESIMS and comprehensive 1D (1H and 13 C) and 2D (gradient multiple quantum filtered 1H-1H COSY, 1H-13C HSQC and 1H-13C HMBC) NMR analyses. The antibacterial and free radical scavenging activity, and general toxicity of these compounds were assessed. While none of these glycosides showed any significant antibacterial activities at test concentrations, all these compounds showed prominent free radical scavenging activity (IC50 values: 1.25×10-2 to 7.69×10-3 mg/mL) in DPPH assay. In the brine shrimp lethality assay very low levels of general toxicity (LD50 >1.00 mg/mL) were displayed. 相似文献
55.
S. R. Sarker D. M. Stone E. J. Evain J. H. Cooley B. L. Scott R. D. Willett 《Journal of heterocyclic chemistry》1994,31(6):1535-1539
Recently we reported the reaction of 1,1-dimethyl-4-substituted semicarbazides with phosgene to occur with formation of several new heterocyclic ring systems. Here we report the reaction of several semicarbazides, thiosemicarbazides and related acyl substituted hydrazides with oxalyl chloride and malonyl chloride. These reactions occur with the formation of heterocyclic products which are oxadiazolinones, imidazolidinetriones, 2-thioxoimidazolindine-4,5-diones, and 2-thioxo-1,3-diazine-4,6-diones (2-thioxopyrimidine-4,6-diones). 相似文献
56.
Nisa Najibah Mahleyuddin Said Moshawih Long Chiau Ming Hanis Hanum Zulkifly Nurolaini Kifli Mei Jun Loy Md. Moklesur Rahman Sarker Yaser Mohammed Al-Worafi Bey Hing Goh Shobna Thuraisingam Hui Poh Goh 《Molecules (Basel, Switzerland)》2022,27(1)
Coriandrum sativum (C. sativum), belonging to the Apiaceae (Umbelliferae) family, is widely recognized for its uses in culinary and traditional medicine. C. sativum contains various phytochemicals such as polyphenols, vitamins, and many phytosterols, which account for its properties including anticancer, anti-inflammatory, antidiabetic, and analgesic effects. The cardiovascular benefits of C. sativum have not been summarized before, hence this review aims to further evaluate and discuss its effectiveness in cardiovascular diseases, according to the recent literature. An electronic search for literature was carried out using the following databases: PubMed, Scopus, Google Scholar, preprint platforms, and the Cochrane Database of Systematic Reviews. Articles were gathered from the inception of the database until August 2021. Moreover, the traditional uses and phytochemistry of coriander were surveyed in the original resources and summarized. As a result, most of the studies that cover cardiovascular benefits and fulfilled the eligibility criteria were in vivo, while only a few were in vitro and clinical studies. In conclusion, C. sativum can be deemed a functional food due to its wide range of cardiovascular benefits such as antihypertensive, anti-atherogenic, antiarrhythmic, hypolipidemic as well as cardioprotective effects. 相似文献
57.
Direct purification of pectinase from mango (Mangifera Indica Cv. Chokanan) peel using a PEG/salt-based Aqueous Two Phase System 总被引:2,自引:0,他引:2
An Aqueous Two-Phase System (ATPS) was employed for the first time for the separation and purification of pectinase from mango (Mangifera Indica Cv. Chokanan) peel. The effects of different parameters such as molecular weight of the polymer (polyethylene glycol, 2,000-10,000), potassium phosphate composition (12-20%, w/w), system pH (6-9), and addition of different concentrations of neutral salts (0-8%, w/w) on partition behavior of pectinase were investigated. The partition coefficient of the enzyme was decreased by increasing the PEG molecular weight. Additionally, the phase composition showed a significant effect on purification factor and yield of the enzyme. Optimum conditions for purification of pectinase from mango peel were achieved in a 14% PEG 4000-14% potassium phosphate system using 3% (w/w) NaCl addition at pH 7.0. Based on this system, the purification factor of pectinase was increased to 13.2 with a high yield of (97.6%). Thus, this study proves that ATPS can be an inexpensive and effective method for partitioning of pectinase from mango peel. 相似文献
58.
Sarker and Parija have developed a model for obtaining the optimal batch size for a single-product manufacturing system operating under a fixed-quantity, periodic delivery policy. In this work, the model is extended to a multi-product situation and a single-facility scheduling scheme is developed for the system. Two situations are considered—one with fixed setup cost and the other with variable setup cost. It is observed that setup cost variability is beneficial to the system under certain conditions. 相似文献
59.
Ananda Sarker Paul M. Lahti Frank E. Karasz 《Journal of polymer science. Part A, Polymer chemistry》1994,32(1):65-71
The reaction of bis(4,7-tetrahydrothiopheniomethyl) benzofuran dibromide with aqueous tetramethylammonium hydroxide leads to a water-soluble polyelectrolyte which can be film cast and thermolytically eliminated to give poly(4,7-benzofuran vinylene) (PBFV). Subjection of bis(4,7-tetrahydrothiopheniomethyl) benzothiophene dibromide to the same reaction sequence gives poly(4,7-benzothiophene vinylene) (PBTV). UV-VIS studies show that PBFV has a band gap of 2.76 eV, while PBTV has a band gap of 2.92 eV. These polymers are members of a new class of conjugated poly (arylene vinylene)s, in which heterocyclic pseudoaromatic rings are fused onto a poly(1,4-phenylene vinylene) backbone. © 1994 John Wiley & Sons, Inc. 相似文献
60.
M.?N.?A.?Abdullah S.?Hossain M.?S.?I.?Sarker S.?K.?Das A.?S.?B.?Tariq M.?A.?Uddin A.?K.?BasakEmail author S.?Ali H.?M.?Sen Gupta F.?B.?Malik 《The European Physical Journal A - Hadrons and Nuclei》2003,18(1):65-73
A folding potential describing the
-scattering on 16O over a broad energy range 25.8-146.0 MeV is constructed on the basis of
-like cluster and unclustered-nucleon configurations of 16O. The resulting potential does not need any renormalization to fit the angular distribution of elastic cross-sections. The effects of the repulsive part of
-
and
-nucleon interactions are investigated. The analysis suggests that both the
-
repulsive potential and the unclustered nucleonic configuration in the target are important to describe the scattering data over a broad range of incident energies. The root-mean-square radius for the 16O nucleus is deduced.Received: 5 December 2002, Published online: 9 October 2003PACS:
25.55.Ci Elastic and inelastic scattering - 24.10.Ht Optical and diffraction models - 21.60.Gx Cluster models 相似文献