Helical distributions of stokeslets

Helical distributions of stokeslets can valuably model microbial locomotion through a fluid, and also the flow field generated, wherever a flagellum actively executes helical undulations (as in many single-celled algae and protozoa) or where (as in many bacteria) the action of rotary motors causes a passive structure of helical shape (which may be a flagellum or else the cell body itself) to rotate. Here, previous biomechanical studies of such modes of locomotion are extended to include analyses of three-dimensional flow fields. In some cases, a rotlet field (curl of a stokeslet) needs to be incorporated in the models. For example, spirochete swimming is modelled by combined helical distributions of stokeslets and rotlets; the computed flow field being confined to within distances of less than twice the radius of the cell body's helical shape from its axis, while including a powerful jet-like interior flow through the coils of the swimming spirochete.     

Anodic oxidation of mecoprop herbicide at lead dioxide

The electrochemical oxidation of an aqueous solution containing mecoprop (2-(2-methyl-4-chlorophenoxy)propionic acid) has been studied at PbO₂ anodes by cyclic voltammetry and bulk electrolysis. The influence of current density, hydrodynamic conditions, temperature and pH on the degradation rate and current efficiency is reported. The results obtained show that the use of PbO₂ leads to total mineralization of mecoprop due to the production of oxidant hydroxyl radical electrogenerated from water discharge. The current efficiency for the electro-oxidation of mecoprop is enhanced by low current density, high recycle flow-rates and high temperature. In contrast, the pH effect was not significant. It has also been observed that mecoprop decay kinetics follows a pseudo-first-order reaction and the rate constant increases with rising current density.     

Fast Minor Testing in Planar Graphs

Minor Containment is a fundamental problem in Algorithmic Graph Theory used as a subroutine in numerous graph algorithms. A model of a graph H in a graph G is a set of disjoint connected subgraphs of G indexed by the vertices of H, such that if {u,v} is an edge of H, then there is an edge of G between components C _u and C _v . A graph H is a minor of G if G contains a model of H as a subgraph. We give an algorithm that, given a planar n-vertex graph G and an h-vertex graph H, either finds in time $\mathcal{O}(2^{\mathcal{O}(h)} \cdot n +n^{2}\cdot\log n)$ a model of H in G, or correctly concludes that G does not contain H as a minor. Our algorithm is the first single-exponential algorithm for this problem and improves all previous minor testing algorithms in planar graphs. Our technique is based on a novel approach called partially embedded dynamic programming.     

The influence of simulation time-resolution on the matching between on-site micro-wind generation and building electric demand

This paper is to investigate the unique impact of simulation time-resolutions on energy matching between on-site micro-wind turbine and household electric demand. The focused indices are on-site electrical energy fraction (OEFe), on-site electrical energy matching (OEMe), and their errors (e_OEF and e_OEM). The methodology consists of parametric analyses with respect to time-resolution levels, averaging methods, demand profiles, turbine capacities, and wind conditions. Two averaging methods are used: ‘Speed Averaging’ and ‘Power Averaging’. With a coarser resolution, two averaging effects have been found. One is an overestimation effect by both the averaging methods, which are more likely to be encountered especially when a high-resolution generation curve frequently crosses intermittent long spikes of a demand curve. The other effect is an underestimation effect on OEFe simultaneously occurring with the Speed Averaging Method under the conditions of (1) a low wind speed and (2) a high unstable wind speed and a low turbine capacity.     

Urban Development the Pattern and the Background; Concluding Discussion

When We Build Again. A Bournville Village Trust Research Publication. George Allen &; Unwin, Ltd., London, 1941. Pp. xii (16), 138.

Report Relative to Postwar Reconstruction in the City, Prepared by Improvements and Town Planning Committee, published by The Corporation of London, 1944, pp. 66 plus maps and photographs.

The Economic Status of the New York Metropolitan Region in 1944, by The Regional Plan Association, Inc., New York, 1944, xx, 91 pp.     

Government Subsidy for Housing in Great Britain

The Economic Reports of The President, January 1948, January 1947 and July 1947. With an Introduction by the Council of Economic Advisors. Reynal &; Hitchcock, New York. 307 plus xiv pages. $2.50.

The Master Highway Plan for the Boston Metropolitan Area. By The Joint Board for the Metropolitan Master Highway Plan, Charles A. Maguire &; Associates, De Leuw, Cather &; Co., and J. E. Greiner Co., Consultants, Boston. Feb. 1948. 121 pages and key maps.

A Critical Review of Research in Land Economics. By Leonard A. Salter, Jr. The University of Minnesota Press. 1948. 258 pages. $4.00.

Land Economics. By Roland R. Renne Harper and Brothers. 1947. 736 pages. $5.00.

The Redevelopment of Central Areas. The Ministry of Town and Country Planning. H. M. Stationery Office, London, 1947. 99 pages, illustrated in color. Obtainable in the U.S.A. through the British Information Services, Rockefeller Center, New York. $3.65.

Pierre Sur Pierre, Construction du Nouvel Urbanisme. By Gaston Bardet. Plans, photographs, diagrams. Editions L. C. B. Section Batiment, Paris, 1946-47. 290 pages.

Planificacion y Sociografia. By Dr. Miguel Figueroa Roman, Instituto de Sociografia, Colegio Libre de Estudios Su-periores, Tucuman, Argentina, 1946. 201 pages.     

霸气镇八方——微软Reclusa键盘

Habu鼠标的上市,加上IE3．0复刻版等键鼠产品的热销,给了微软很大的信心。而在市场反应上,微软和RaZER的产品也是一帆风顺。对于和RaZER联合的初见成效,微软肯定不会中途断档。Reclusa键盘的推出,就是两家著名外设厂商通力合作的成果。     

掌控中场的“大脑”-罗技“卡尔·蔡司”系列摄像头首测

2007年8月1日,著名外设供应商罗技公司推出3款高端网络摄像头新品——罗技快看合金版Pro9000、快看迷你高清版和快看高手加强版。对于摄像头,普通用户只关心其性能而非质量,网吧老板更甩出了“能看见四条胳膊一个脑袋就行了呗”的言论,足见摄像头在一套成型计算机中的地位。但罗技公司的产品从根本上改变了甩户对于视频产品的看法。