Grain Refinement of Casting Aluminum Alloys of the Al–Mg–Si System by Processing the Liquid Phase Using Nanosecond Electromagnetic Pulses

Russian Journal of Non-Ferrous Metals - In this paper, using the AA 511 alloy of the Al–Mg–Si system as an example, it is shown that the irradiation of aluminum melts with nanosecond...     

Equivalent linear limit states

The replacement of any limit state function by an equivalent linear function is discussed in detail and it is shown that there are several methods by which such an equivalence may be established. In the case of multiple failure mode problems the definition of fully equivalent linear functions requires the additional consideration of mode correlations. The manner in which this may be carried out is discussed and it is shown that, for most practical cases, a relatively simple analysis is likely to be sufficient to define the set of equivalent linear limit states, with the advantage that the established theory of such linear limit states may then be employed in the majority of reliability analyses.     

Lead and cadmium in teeth,bone and kidneys of rats with a standard Pb‐Cd supply

Male Wistar rats received a combination of 25 ppm PbCl₂ and 5 ppm CdCl₂ in drinking water at different developmental stages. Pb and Cd levels of incisors, molars, epiphyses, diaphyses and kidney cortex were recorded by atomic absorption spectrophotometry. The results confirmed that Pb has an affinity for hard tissue and especially to teeth, but it also accumulated in soft tissues under the above conditions. In addition, the results indicated none or only a moderate placental or mammary barrier for Pb, and suggested a high absorption of lead from the intestine of sucklings. The results also confirmed that kidney cortex is a primary target for Cd, and indicated that Cd has crossed the placental and mammary barriers to some degree. The positive significant correlation between Cd levels in molars and kidney cortex suggested that rodent molars indicate a degree of Cd absorption, whereas incisors do not. It is supposed that rodent molars are comparable to human deciduous teeth. It is thus confirmed that human deciduous teeth indicate previous lead exposure. It is further inferred that they also can be used as indicators of previous Cd‐exposures.     

The use of site surveys in the collection of recreation data,with particular Reference to the congleton district of Cheshire

The provision of countryside recreation facilities at a local level is likely to receive increasing attention during the next decade. As an integral part of the assessment of the quality of present provision within the Congleton District of Cheshire (U.K.) five site surveys were made. Each site provides different facilities for recreation and interview questions were designed to investigate the background of the visitors and the nature of the interplay between site and visitor. The analysis of answers attempts to illustrate those aspects of this interrelationship, which may be important during the consideration of future provision of recreation sites and their management.     

Changes in zooplankton populations in the White Volta with particular reference to the effect of Abate

The 24‐hour LC 50 of the nauplii of Thermocyclops hyalinus using Abate CE 200 solution was 0.23 ppm., while the 24‐hour LC 50 of both the copepodite and adult stages was 0.2 ppm.

The numbers of drifting zooplanktonic Microcrustacea in the White Volta increased in numbers during the months of March, April, May, June and July in the dry season. The increase in numbers in the post‐sunset samples related to the vertical migration of the zoqplankton in the reservoir upstream. The aerial weekly application of Abate CE 200 solutions at very high lethal concentrations did not seem to affect the Microcrustacea population probably because (a) Microcrustacea drifting into the reservoir from upstream sustained populations in the reservoir; (b) Microcrustacea living at the banks of the reservoir escaped the abate effect flowing downstream; and (c) spraying was done around noon, when the majority of the zooplankton population had migrated to the bottom of the reservoir.     

Andalusia,Spain: An Assessment of Coastal Scenery

The 1101 km length of the Andalusian coast (Spain) was assessed for coastal scenery at 45 specific locations. Selected areas covered resort (3), urban (19), village (8), rural (10) and remote (5) bathing areas. Scenery was analyzed for physical and human parameters via 26 selected parameters. These parameters were obtained by interviews of >500 people on European beaches. Each parameter was assessed via a one-to-five-point attribute scale, which essentially ranged from presence/absence or poor quality (1), to excellent/outstanding (5). Results were subsequently weighted by interviewing >600 bathing area users (not all 26 parameters have equal weight) and subjected to fuzzy logic mathematics in order to reduce recorder subjectivity. High weighted averages for attributes 4 and 5 (excellent/outstanding) reflected high scenic quality, vice versa for attributes 1 and 2. Sites were classified into five classes ranging from Class 1 sites having top grade scenery to Class 5, poor scenery. Seven sites each were found in Classes 1 and 2; 10 sites each in Classes 3 and 5; 11 sites in Class 4. The finest coastal scenery was found in remote areas whilst urban areas scored mainly as Class 3 or 4. Three out of the ten rural sites had Class 3 and 4 values assigned them whereas the rest scored as Class 1 and 2; village sites invariably had scores within Class 3 and 4. Of the three resort sites investigated, one scored as a Class 1 site, the others as Class 3.     

Town and Country Planning in England's Northeast Section

Abstract

A SYMPOSIUM OF CURRENT PLANNING THEORY: Planning for America , By GEORGE B. GALLOWAY AND ASSOCIATES. Henry Holt and Co., New York; 713 pages, price $3.

A TEXTBOOK ON SUBDIVISION: Subdivision Regulations: An Analysis of Land Subdivision Control Practices. By HAROLD W. LAUTNER. Public Administration Service; 346 pages, price $3.75.

EMPLOYMENT IN THE REGIONAL DEVELOPMENT OF RESOURCES: Development of Resources and Stabilization of Employment in the United States. By THE NATIONAL RESOURCES PLANNING BOARD; 409 pages, price $1.20.     

Development of a continuous respirometer

A continuous oxygen uptake meter or continuous respirometer was developed which produced a rapid and reliable response to systemic shocks. The respirometer basically is a 101. Plexiglas laboratory activated sludge unit with a variable volume air tight side car. The feed enters the completely mixed aeration basin and is pumped into the side car. The side car is the site of the oxygen uptake measurements as indicated by a continuously monitoring dissolved oxygen probe. The system was most sensitive to changes in influent concentrations when run at an F/M = 0.1. Response time for a change in DO of 0.1 ppm was less than 4 min. The continuous respirometer was tested employing both synthetic and raw industrial wastes.     

Polychlorinated naphthalenes in air and snow in the Norwegian Arctic: a local source or an Eastern Arctic phenomenon?

PCNs were measured in air and snow during separate field campaigns at Ny-Alesund (April 2001) and Troms? (February/March 2003) in the Norwegian Arctic. Air concentrations ranged from 27 to 48 and 9 to 47 pg sigmaPCN m(-3) for Ny-Alesund (n=6) and Troms? (n=10), respectively. These concentrations (including the tri-chlorinated naphthalenes) greatly exceeded concentrations previously measured in the Canadian Arctic, but did fall within the upper range of concentrations observed over the eastern Arctic Ocean and regional seas. Local sources appear to be affecting concentrations observed at both sites, with the presence of several hexa-chlorinated naphthalenes at Troms? probably attributed to local/regional sources. Use of air mass back trajectories at Troms? revealed that background air concentrations in the Norwegian Arctic are likely to range between <9 and 20 pg sigmaPCN m(-3) and that contemporary concentrations derived close to potential sources (i.e. arctic towns) may equal or exceed those of PCBs. The mean concentration in surface snow was 350 and 240 pg sigmaPCN L(-1) (meltwater) (or 0.014 and 0.01 pg g(-1) (snow)) at Ny-Alesund and Troms?, respectively. The wide variation in concentrations observed between fresh snowfalls could be explained by different snow densities (as a surrogate of snow surface area), rather than attributed to varying air concentrations. A statistically significant inverse relationship was found between snow density and concentrations of tri- to penta-chlorinated homologues and compliments similar findings for the polychlorinated biphenyls (PCBs). This suggests that the vapour-sorbed quantity changes rapidly with snow ageing/compaction; with implications for the fate of these chemicals in the Arctic.