Composites with planar reinforcements (flakes,ribbons)—A review

Unlike fibers, planar reinforcements, such as flakes and ribbons, provide reinforcement in two directions. If such reinforcements are arranged parallel to their principal plane in a composite material, they thus provide a distinctly higher performance than fiber reinforcements for two-dimensional loading conditions. This higher performance amounts to about a factor three for the Young's modulus and a factor two for the tensile strength. However, in spite of this obvious advantage, composites with planar reinforcements are as yet relatively unknown. This is mainly due to the fact that planar reinforcements are not as readily available as fiber reinforcements and therefore not much work has been done on them. The present article gives first a short outline of the theory of the elastic and tensile properties of composites with planar reinforcements. Then, a non-exhaustive review is presented of the work on composites with planar reinforcements, with particular attention given to recent developments. A final aim of this article is that by showing the merits of planar reinforcements as compared to presently existing fiber reinforcements, it may contribute to their use in the design of composite structures.     

Unmasking the phantom: Creative assessment of the adolescent.

Discusses the need for enhanced and more creative assessment techniques in evaluating the adolescent population. Creative alternatives for more accurate and inclusive assessment are described, with emphasis on issues of rapport and empowerment. Prior to the initial diagnostic interview, it is important to meet with the parents or caretakers to explore the presenting concerns and to set parameters for what the assessment process involves. The final stage of assessment, diagnosis, and recommendations needs to be an active process. An enhanced clinical and functional assessment of the adolescent may increase the success rate of various psychotherapeutic interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two techniques for improving performance on bus-based multiprocessors

In this paper, we explore two techniques for reducing memory latency in bus-based multiprocessors. The first one, designed for sector caches, is a snoopy cache coherence protocol that uses a large transfer block to take advantage of spatial locality, while using a small coherence block (called a subblock) to avoid false sharing. The second technique is read snarfing (or read broadcasting), in which all caches can acquire data transmitted in response to a read request to update invalid blocks in their own cache.

We evaluated the two techniques by simulating 6 applications that exhibit a variety of reference patterns. We compared the performance of the new protocol against that of the Illinois protocol with both small and large block sizes and found that it was effective in reducing memory latency and providing more consistent, good results than the Illinois protocol with a given line size. Read snarfing also improved performance mostly for protocols that use large line sizes.     

A 128 K×8 70-MHz multiport video RAM with auto registerreload and 8×4 block WRITE feature

An 80-ns 1-Mb multiport video random-access memory (VRAM) can be organized as 128 K×8 or 256 K×4. Uninterrupted serial data streams of 70 MHz are achieved by combining pipelining and interleaving techniques with an internally triggered automatic memory-to-register transfer mechanism. DRAM bandwidth is enhanced by a block WRITE feature which can write as many as four column address locations in every CAS cycle. The write-per-bit feature has been expanded by including an on-chip write-per-bit latch and an extended mode of operation to simplify its use in a wider range of systems. The VRAM is fabricated in a 1 μm CMOS technology using double-level poly/polycide, single level metal, and trench DRAM storage capacitors for high noise immunity     

A note on probabilistic computation of earthquake response spectrum amplitudes

This paper analyzes a method for computation of Pseudo Relative Velocity (PSV) spectrum and Absolute Acceleration (SA) spectrum so that the amplitudes and the shapes of these spectra reflect the geometrical characteristics of the seismic environment of the site. The estimated spectra also incorporate the geologic characteristics at the site, direction of ground motion and the probability of exceeding these motions. An example of applying this method in a realistic setting is presented and the uncertainties of the results are discussed.     

Education for Research in Psychology.

Comments on the report of the Estes Park Seminar on Education for Research in Psychology (Amer. Psychologist, 1959, 14, 167-179). The seminar apparently advocates the doctrine of the golden mean: theory, breadth of scholarship, statistics, etc. are not bad, are indeed necessary; but there is a serious danger that they may be carried to excess. This is no doubt true; but the warning is anchored neither by specific recommendations, nor by any relevant data, nor even anything more than a lip service suggestion that it would be useful to investigate curriculum problems in an objective way. There is thus a serious danger that the seminar's report will be all things to all men and that energy which could be spent in such investigation will be dissipated in arguing out compromises of opinions based on insufficient data. It is the purpose of this note to present evidence on one aspect of the problem: that of statistics training. Psychology will be fortunate if the members of the seminar set their manifold talents to bringing the greater problems of graduate instruction out of the domain of personal-impression correlations and into the light of objective and of experimental evidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The absence of a solid layer of helium on alkaline earth fluoride substrates

Journal of Low Temperature Physics -     

A computer technique for the estimation of the absolute three-dimensional array of basal dendritic fields using data from projected histological sections

The standard projection methods of dendritic field analysis have revealed that dendritic density decays exponentially with increasing distance from the centre of the perikaryon and present ideas about dendritic connectivity are largely based on this theory. However, inherent in the projection method are a series of errors which have not hitherto been defined and which indicate that much of the data obtained by the projection technique may be an artefact of the method itself. However, it is possible, given the projection data from a sample of neurons, to extrapolate the three-dimensional array of dendritic fields by employing a computer technique. In this technique the perikaryon is enclosed in concentric spheres set 20 mμ apart and dendritic endings (E) and branching nodes (B) are positioned within the volume of the total sphere according to known distributions. The number of dendritic intersections (I) at the surface of the nth concentric sphere can be calculated given the number of primary dendrites from the relationship; I_{(n ? 1)} + B_n — E_n. These numbers may then be corrected for the distortion due to projection and sectioning. Comparison of these corrected data with those obtained from conventional histological methods suggests that the distribution of dendritic parameters may be quite different from the conventionally held view and that the decay of dendritic density is not exponential.