Microstructural changes in concretes with sulfate exposure

In prior papers the responses of concretes to 50,000 ppm MgSO₄ exposure depending on cement type, w/cm and the presence of slag were described. The present paper completes this analysis by examining the effects of immersion of concretes produced using slag blended cements, in solutions containing 50,000 ppm of sodium sulfate. The spatial evolution of microstructure associated with carbonation and sulfate attack show differences which can be related to the nature of the cation associated with the sulfate, the cement type, and the w/cm ratio.     

智能型激光控制器提高灵活性并节省空间

激光二极管是宽带调幅光纤发射系统的核心器件。光纤系统依赖于激光的稳定性,但未受调节控制的激光二极管特性却常因制造误差、温度和使用日久所造成的参数改变而变得不稳定。因此,光纤通信系统需要专用电路来控制重要的激光二极管参数,以确保它们稳定操作。虽然激光控制电路都     

Mothers' supervision of their children's peer play: Relations with beliefs, perceptions, and knowledge.

Mothers (N?=?76) of 3- to 5-year-old children completed questionnaires assessing beliefs in the importance and modifiability (vs. innateness) of children's peer relationship skills, perceptions of their children's social competence with peers, and strategies they would use in response to children's peer interaction problems. A subsample of mothers (n?=?34) was observed supervising the play of their own children and a peer. Maternal perceptions of children's competence were negatively associated with the extent of mothers' involvement in children's play, whereas the quality of supervision was predicted by knowledge of socialization strategies and the interaction of beliefs and knowledge. Beliefs appeared to moderate the effects of maternal knowledge on mothers' behavior in that knowledge was associated with the quality of supervision only when mothers believed social skills were important and modifiable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geotechnical Investigation Strategies for Lunar Base

Geotechnical characterization of potential lunar sites will be a critical part of the planning and design process. The strategies used to conduct a geotechnical investigation will be dictated by the specific needs of the lunar base, the unique environment of the lunar surface, and general character of the lunar soils and rocks. This paper outlines some of the types of geotechnical information that will be important and identifies some of the more promising strategies which might be used to obtain such information in the lunar environment. Some of the most important geotechnical information for planning and site development will be related to construction in the lunar soil. In addition to construction concerns, geotechnical data for foundation design (or verification of predesigned foundations) will be needed. The geotechnical site‐characterization work should include geophysical techniques, supplemented by conventional mechanical boring and testing only to the degree necessary to correlate geophysical measurements with conventional soil properties and to investigate anomalies. Equipment used for geotechnical site characterization will also serve for mineralogical exploration. Several techniques for geotechnical investigation that may provide very useful information in an expedient manner are described. Geophysical methods include seismic and electromagnetic methods, including seismic surveys that utilize surface waves. Electromagnetic methods such as ground‐penetrating radar are fast, efficient methods for mapping the subsurface, although these techniques do not measure soil characteristics that can readily be correlated with engineering properties. Seismic methods provide information that may correlate with soil strength, compressibility, and excavatability. In‐situ physical testing will likely include penetration testing for direct physical measurement of lunar soil behavior.     

Encountering misspellings and spelling performance: Why wrong isn't right.

Experience with misspellings can be detrimental to subsequent spelling performance. Generating or being exposed to incorrect spellings between two successive spelling tests interfered with subsequent spelling accuracy of these same words in Experiments 1 and 2 (but not Experiment 3), as indicated by changes from correct to incorrect spellings (CI changes). Furthermore, significantly more CI changes occurred when a recognition test (with incorrect versions as distractors) followed a dictation test than when a second dictation test followed it. Repeatedly presented misspellings were rated as looking progressively more similar to the correct spelling across presentations (Experiment 3). These outcomes suggest that spelling tests that involve the discrimination of correct from incorrect versions may be ill advised. In addition, the instructional technique encouraging students to intentionally produce misspellings of words, for purposes of visual comparison, may be detrimental rather than helpful. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Targets and methods for the detection of processed animal proteins in animal feedstuffs

Bovine spongiform encephalopathy (BSE), or ‘mad cow disease’, is one of several transmissable spongiform encephalopathies (TSEs) known to affect certain mammals and is spread through the ingestion of infected animal tissue. It is believed that the inadvertent contamination of meat and bone meal (MBM) with infected animal tissue and the subsequent use of this material as a feed supplement contributed to the spread of the disease in cattle. As a result, the use of processed animal proteins (PAPs) in animal feeds is regulated in many parts of the world. Although feed testing is the only definitive means to certify compliance, regulatory compliance often relies solely on paper certification. Recently, rapid methods have become available that can be used by regulators to determine compliance during routine inspections. We describe a rapid, immunochromatographic strip test that can detect 0.1% MBM in animal feed. The test takes 15 min to perform and large numbers of samples can be screened for PAPs simultaneously.     

Global optimization with multivariate adaptive regression splines.

This paper presents a novel procedure for approximating the global optimum in structural design by combining multivariate adaptive regression splines (MARS) with a response surface methodology (RSM). MARS is a flexible regression technique that uses a modified recursive partitioning strategy to simplify high-dimensional problems into smaller yet highly accurate models. Combining MARS and RSM improves the conventional RSM by addressing highly nonlinear high-dimensional problems that can be simplified into lower dimensions, yet maintains a low computational cost and better interpretability when compared to neural networks and generalized additive models. MARS/RSM is also compared to simulated annealing and genetic algorithms in terms of computational efficiency and accuracy. The MARS/RSM procedure is applied to a set of low-dimensional test functions to demonstrate its convergence and limiting properties.     

On the Auditory Modality Superiority Effect in Serial Recall: Separating Input and Output Factors.

The modality effect in immediate recall refers to superior recall of the last few items within lists presented in spoken as opposed to printed form. The locus of this well-known effect has been unclear. N. Cowan, J. S. Saults, E. M. Elliott, and M. Moreno (2002) introduced a new method to distinguish between the effects of input serial position, output serial position, and the number of items yet to be recalled and found that large modality effects occurred only in conditions in which delay and interference at output (from items already recalled) was high. The authors replicated that finding, even when the response period included output interference acoustically similar to the spoken stimuli to be recalled. However, the authors found that output delay and interference act only by lowering the level of performance to a more sensitive range. The modality effect thus originates during encoding of the list to be recalled, not during output. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

由铬皮边脚料制明胶

商业制革厂得到的铬皮边料用两步法进行消化。 第一步：边皮料、水、表面活性剂和氧化镁一起，在一个鞣革转鼓中转动6h，转鼓温度控制在72℃，随后将反应混合物在温热情况下通过一个普通的压滤机进行过滤，目的是为了使可胶化的蛋白质（gelable protein）滤液与铬泥渣（Chrome sludge）分开。