The Case of The Case Study in City Planning and Municipal Management

Abstract

PLAN FOR REZONING THE CITY OF NEW YORK. A Report by Harrison, Ballard &; Allen. City Planning Commission. New York. 1950. 290 pp. maps, illustrations. $2.00.

CONTROLLED ACCESS EXPRESSWAYS IN URBAN AREAS—A symposium. Highway Research Board Bulletin No. 25. Washington, D. C., 1950. 45 pages, illustrated. 60 cents.

SOCIAL PRESSURES IN INFORMAL GROUPS. By Leon Festinger, Stanley Schachter and Kurt Back. Harper Bros., New York, 1950. x-930 pp. $3.00.

PRODUCTION OF NEW HOUSING. A Research Monograph on Efficiency in Production. By Leo Grebler. Social Science Research Council. New York 1950. ix+ 186 pp. $1.75.     

保障性住房的公共服务体系建构

通过对保障性住房目标人群的居住需求分析归纳出:居住需求可根据时间分为“永久性”与“非永久性”;居住空间可根据功能分考“核心”与非核心”功能空间:基于预期需求的住宅产品价值消费具有被动性特点.在此基础上,结合我国保障性住房建设的约束性条件,提出若干保障性住房的公共服务功能建设构想.     

谈如何控制路基压实

分析了影响路基压实的因素,并从含水量、土质、压实厚度等方面进行了论述,探讨了有效控制路基压实度的注意事项,以选用正确的施工方式,确保路基压实质量满足设计要求。     

Non-linear analysis of membrane action effect in profiled steel sheeting dry board flooring system

This study highlights the effect of membrane action in improving load carrying capacity of Profiled Steel Sheeting Dry Board (PSSDB) floor system. PSSDB system is a lightweight composite structural system composed of profiled steel sheeting and dry board, attached together by self-drilling and self-tapping screws. Many literatures have reported that restricting conventional slabs, such as reinforced concrete slab, at the supports against translation and/or rotation while it is subjected to vertical loading develops the compressive membrane action in the slab. The development of this phenomenon is considered in the PSSDB system with concrete infill for continuous and practical spans, with and without topping concrete. Previous authors’ experimentally verified non-linear finite element model for the PSSDB floor without topping was extended to parametrically predict the effect of different boundary conditions on the performance of the system for practical applications. It was revealed that preventing the in-plane movement of the slab ends improves the flexural rigidities of the slab up to more than three times when considering central deflection of serviceability limit state. This was observed when the deflection limit load of the fixed both end supports model was compared to the pin-roller support model. Moreover, the topping concrete enhances the applicability of the system in longer span and the developed compressive membrane action dramatically boosts the load carrying capacity of the slab with restricted translation and/or rotation of the slab ends.     

产业性城市中小企业簇群的培育

针对一些产业性城市目前面临着产业衰败导致城市衰败的威胁，探讨通过培育中小企业簇群实业产业性城市的产业整合，提升城市的竞争力。     

Effects of copper, pH and hardness on the critical swimming performance of rainbow trout (Salmo gairdneri Richardson)

Critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness. Measurements were made after exposure for 0.5, 5, 10, and 30 days. When copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance. Copper had the greatest effect on swimming performance at 5 days of exposure. At pH 7.5–8.0, recovery from the initial depression was complete after 10 days of exposure, but critical swimming performance did not return to control levels in pH 6.0 treatments. For any given hardness, copper had a greater effect on critical speed at low than at high pH. A given copper treatment had a more pronounced effect at low than at high hardness.No distinction could be made among total, soluble, or extractable copper but predicted concentrations of 6 specific cupric ions varied with pH and hardness. Of these copper species, only Cu²⁺ and CuOH⁺ were found to be related significantly to critical performance.Oxygen consumption of trout was determined in different combinations of copper and pH. In the presence of copper the maximum oxygen consumption decreased and the energy expenditure for a given swimming speed increased.The above observations are discussed in relation to reported toxic actions of copper.     

Mechanical and Tribological Properties of Ca/P-Doped Titanium Dioxide Layer Produced by Plasma Electrolytic Oxidation: Effects of Applied Voltage and Heat Treatment

Plasma electrolytic oxidation (PEO) is a technique that produces a hard oxide layer on the titanium surface where its properties can be tailored by changing the process parameters or by a posterior heat treatment (HT). In this work, a TiO₂ layer with different crystallinity was produced by PEO with different applied voltages (250 to 400 V) and post-HT at 600°C. Our aim was to evaluate the influence of the PEO voltage and HT on the mechanical and tribological properties of anodized Ti. There is an increase in pore size, oxide thickness, and Ca/P ratio for the oxide layer with the applied voltage during the PEO process. X-ray diffraction (XRD) results indicated an increase in the crystalline rutile phase in the oxide layer with voltage and HT. Nanoindentation shows an increase in the oxide hardness and elastic modulus with increased voltage and HT, leading to an improvement in the wear resistance.     

Sintering Behavior and Dielectric Properties of Ultra‐Low Temperature Fired Silver Molybdate Ceramics

Ag₂MoO₄ ceramic was prepared by using the solid‐state reaction method, which could be sintered at 450°C for 2 h, having a relative permittivity of 8.08, a Qf value of 17 000 GHz, and a temperature coefficient of resonance frequency about ?133 ppm/°C. Ag₂MoO₄ ceramic was chemically compatible with silver but reacted seriously with aluminum to form (Ag_0.5Al_0.5)MoO₄ during the sintering. The fitting of infrared spectra and the Shannon's additive rule were employed to study intrinsic dielectric behaviors of the ceramics at microwave region. Ionic displacive polarization and the electronic polarization contributed almost equally to the dielectric permittivity of the ceramic at microwave region. The Ag₂MoO₄ ceramics could be a good candidate for ultra‐low temperature co‐fired microwave devices.