Comparative effects of cement,coal dust and fly‐ash on H. Abelmoschus

Three types of dusts, i.e. cement, coal and fly‐ash were applied daily at the rate of two grams per square metre per day to 15 days old plants for a period of one month. Visible foliar symptom, photosynthetic pigment content and dry weight were taken as parameters. Small chlorotic spots and marginal chlorosis appeared in leaves sprayed with cement and coal dust respectively. Cement dust was more toxic to chlorophylls than coal dust, while a slight increase was noted in case of fly‐ash. Carotenoids were relatively unaffected by dust pollution.     

Chloride ion diffusivity of fly ash and silica fume concretes exposed to freeze–thaw cycles

This research focuses on investigating the durability of concretes containing fly ash and silica fume exposed to combined mode of deterioration. For this purpose, the chloride ion diffusivity of concrete was evaluated before and after 300 freeze–thaw (F–T) cycles. It was found that the coefficient of chloride ion diffusivity (CCID) increased as water to cementitious material ratio (w/cm) and air content increased. Test results clearly showed that CCID for all concretes increased after F–T cycles. In addition, concrete incorporating silica fume showed the lowest CCID and highest durability factor (DF), regardless of curing regime, air content, and w/cm. However, fly ash concrete showed good resistance to chloride ion diffusivity before and after F–T cycles when low w/cm as well as a proper curing and air content were provided.     

Strength characteristics of illinois coal combustion by‐product: PCC dry bottom ash

The coal combustion by‐product, dry bottom ash, originates from the burning of pulverized coal to produce electricity. Currently, almost all of the pulverized coal combustion (PCC) dry bottom ash is being dumped into ash ponds and landfills. Some of the ash ponds are reaching their maximum capacity and there is an immediate need for alternative measures to either dispose of or utilize the coal combustion by‐products for construction purposes. Within the past five years, several studies have investigated the use of PCC dry bottom ash in concrete and concrete products. However, its use in geotechnical applications is very limited. The physical properties of Illinois PCC dry bottom ash are similar to that of natural sand with particle sizes ranging from fine gravel to fine sand. Shear strength characteristics of soils, or materials similar to soils, are the most important parameters needed for the design of any geotechnical engineering project. Therefore, this study was initiated to develop understanding of the shear behavior of Illinois PCC dry bottom ash so that its potential use in geotechnical engineering applications could be accessed. This paper presents the results of an experimental study conducted to develop the technical data on shear strength characteristics of Illinois PCC dry bottom ash amended with bentonite.     

Retrospect and Prospect of the Protection and Reconstruction of Old Beijing

Beijing is a famous,cultural and ancient capital inour country and one of the first group of famous,histori-cal and cultural cities proclaimed by the State Council.The Imperial Palace,the Great Wall and the Ape—manCave are listed as the” world cultural heritage”,whichhas further confirmed Beijing’s historical position in theworld.It has always been an important task in the field ofBeijing’s overall planning to protect this historical citywell while carrying out its modernization.At present,itbecome more important to do so for Beijing when the re-form and opennng policy is accelerated,the socialist mar-ket economy is being set up and the development of thecity is speeded up.To protect and reform the old Beijing,a great dealof valuable exploration has been put into practice overthe past more than 40 years.The work is now heing putinto a more scientific course.A few points of view are asfollows:     

iple and Application of

the Distributed Optical Fiber Sensors Based on OTDRNI Yu-ting,L Chen-gang,GE Chun-feng,WU Xing(College of Precision Instrument and Opto-Electronics Engineering,Tianjin University,Tianjin 300072,China)The current development and trend of distributed optica     

Mobility of Urban and Rural Labour and Urbanization

By defining urbanization, the author approached the mobilityof labour between countryside and cities and pointed out that thismobility was determined by the capacity and repulsive force of agri-culture as well as urban attraction and absorbency. While analysingthe relations between the four determinative factors, the author ex-pounded different channels of labour transfer under conditions ofbalance and imbalance.     

City Model of Guilin and Object of Protection

The city model of Guilin,characterized by the unique integration of hills,rivers and city,is being sabotaged dur-ing the urbanization process.This article makes an analysis of problems facing Guilin and proposes measures fromthe planning point of view.These measures,including regional macrocontrol and microcontrol of the developmentareas,intend to protect the city's integrity,to propose development controls and to retain the local characteristics.     

PS防水包装涂料

PS防水包装涂料利用废旧泡沫PS为主要原料,经过改性生产出高效防水包装涂料。它具有成本低、工艺简单、效益好等特点。经过涂料基本性能检测、耐冷热温度变化试验、耐冻融试验、耐水性试验等检验都具有良好的检验结果,在钢铁、水泥、三合板、瓦楞纸板上都有优良的附着力和良好的耐水性。　　PS防水包装涂料原料简单,生产工艺和设备简单,投资少,见效快,适合小型企业生产。所需厂房面积小,生产人员少,投资2万～3万元即可生产出合格产品,利润可达50%左右(含利税),用于纸箱包装防水,每个纸箱成本增加5～9分钱,即可收到3倍或4倍于成本的效…     

PS结构发泡门槛

据报道,美国生产保温门系统的Therma—Trn公司研制的一种PS结构发泡门槛,在外观上和木材相似,但是其性能远远超过木材。作为新的和替换门槛的材料,它可以和铝制品竞争。多年来,由于材料欠缺,因而看起来一般的铝门槛一直是门槛中的佼佼者。因为除了木材外,毫无选择余地,而木材又有磨损和褪色的缺点。这个公司认为,使用这种结构发泡材料的建筑材料,将是一个方向。     

A Review of “Transport and Ethics: Ethics and the Evaluation of Transport Policies and Projects”

URBAN GROWTH DYNAMICS IN A REGIONAL CLUSTER OF CITIES by F. Stuart Chapin, Ir. and Shirley F. Weirs John Wiley and Sons, Inc., New York, 1962. 484 pp. $8.95.

THE COMMUNITY ECONOMIC BASE STUDY by Charles M. Tiebout Committee for Economic Development, New York, N. Y., 1962. 86 pp., 6 figs., 12 tables. $1.50.

INDUSTRIAL RENEWAL by Chester Rapkin and others Bureau of Urban Affairs, New York State Division of Housing and Community Renewal, New York, N. Y., 1963. 77 pp., 12 figs., 29 tables.

INTENSITY OF DEVELOPMENT AND LIVABILITY OP MULTI-FAMILY HOUSING PROJECTS: DESIGN QUALITIES OF EUROPEAN AND AMERICAN HOUSING PROJECTS by Robert D. Katz (F.H.A. Technical Study TS 7.14.) Washington, D.C., Government Printing Office, 1963. v + 115 pp. 79 illustrations, 3 appendices. $2.00.

LAKE EUROPA: A NEW CAPITAL FOR A UNIFIED EUROPE by 1, Marshall Miller New York: Books International, 1963. 114 pp. $3.75.

CONTROLLING LONDON'S GROWTH by Donald L. Foley University of California Press, Berkeley and Los Angeles, California, 1963. 224 pp. $5.00.

LONDON 2000 by Peter Hall Faber and Faber Ltd., London, 1963. 220 pp. Illustrated. 55s.     

Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded.     

PS0816破碎机设备安装

针对破碎机设备安装过程中设备量超载、超高,无法直接采用行车安装的情况,采用了设备整体移位安装,设计专用安装工装,确保了设备安装精度并一次安装到位。     

废PS制造建筑防水剂

一种利用废弃PS制品,经简单处理后制成建筑防水剂的方法,该法所需设备、工艺均较简单.     

PS型混凝土喷射机械手

由南京军区工程兵部设计,如皋县第一建设机械厂制造的PS型混凝土喷射机械手最近在连云港通过了部级新产品生产鉴定。该机设计合理、机构紧凑、技术先进、自动化程度高。通过工业性考核和性能测试,证明其