The aging behavior of orthorhombic marten site in Ti-6-2-4-6

In Ti-6-2-4-6 alloys, beta transforms to orthorhombic martensite when quenched from a temperature of 1188 or above, X-ray analysis showed that aging at 773 or 873 gradually reduces the degree of orthorhombicity until a hexagonal structure equivalent to alpha, but having the morphological characteristics of the prior martensite, is produced. The orthorhombicity is reduced by solute rejection to beta which forms as particles both homogeneously and heterogeneously within the martensitic structure. The structure at maximum hardness is a fine distribution of Burger’s oriented beta particles in a matrix of martensite of greatly reduced orthorhombicity. Overaging appears to occur as a result of coarsening of the homogeneous beta particles. It is shown that aging at temperatures from 873 to 1083 K results in growth of one particular varient of the beta which is located at the interface between twin related regions composing a martensite lath. This beta along with similarly oriented beta at lath interfaces forms a continuous beta matrix by a gradual growth process. It is shown that this matrix has the identical orientation and shape of the original beta grain prior to quenching. A mechanism is proposed to account for this “memory effect”.     

Retention of antioxidants in polyethylene by silane coupling agents

Antioxidant additives in polyethylene films have been shown to diffuse to the surface where they are subsequently lost, exposing the polymer to oxidation. Compatibility of antioxidants with polyethylene may be increased by use of silane coupling agents. In this study, three approaches to antioxidant modification are examined: (1) bonding antioxidant directly to silicon, (2) coupling the silane to an antioxidant hydroxyl function, and (3) dissolving antioxidants in silanes. All three approaches are shown to be effective in reducing antioxidant loss by diffusion.     

Hierarchical control model for automated manufacturing systems

A mathematical model is presented to determine the hierarchical computer control requirements for a completely automated flexible manufacturing systems. This model can estimate the number and capacity of hierarchical computers needed to control a specified automated manufacturing system. The hierarchical control system is described by the major operating components common to all controlling computers and computer numerical controlled (CNC) machines: central processing unit, memory, input/output and communications. Each of these components is evaluated with respect to its operating speed and capacity. Costs are then determined as a function of the component's processing speed and capacity.A three-tier control system is examined. Starting with the CNC machines' speeds and capacities, each level of the computer hierarchical control system is modeled and related to the next tier by communication and data requirements. The physical machine layout required for a hierarchical control system is discussed. Part scheduling and process information requirements are also addressed. The model's utility is illustrated by an example using a typical manufacturing system.Optimization of this model is readily obtained using standard dynamic programming techniques. Being totally independent of any specific computer hardware technology, the model can be applied to present and future automated manufacturing systems.     

Visible light reflectance,transmittance, and absorptance of differently pigmented cotton leaves

Spectrophotometrically measured light reflectance and transmittance, and calculated absorptance over the 0.45–0.70 μm waveband (WB) of four differently pigmented cotton (Gossypium hirsutum L.) leaves are compared. Leaf color appearances were green (G), common red (CR), light red or bronze (B), and yellow-green (YG). The G and YG leaves (chlorophylls and carotenoid) had about the same reflectance and transmittance peaks at the 0.55-μm wavelength (WL), although YG leaves had much higher reflectance and transmittance than G leaves. Anthocyanin pigment manifestation in CR, B, and YG leaves occurred at about the 0.60-μm WL. The red light (0.65-μm) absorptances of leaves in decreasing magnitude were: CR, G, YG, and B. There was little effect on blue light (0.45-μm) absorptance. Spectral responses of cotton leaves were very sensitive to either their masked or predominant pigmentation over the 0.45–0.70-μm WBs. The possible importance of leaf pigmentation to LANDSAT-D's thematic mapper, visible light WBs is discussed.     

The potential uses of a computer animated film in the analysis of geographical patterns of traffic crashes

If one looks at research in progress regarding the phenomenon of traffic crashes, it can be seen that little of this work relates to the analysis of geographic patterns of traffic crashes. The geographic approach involves the analysis of patterns of data in a two dimensional spatial domain utilizing points and lines as primitives. Broadly speaking, the approaches which are applicable here are distributional, residual and cluster analyses in one and two dimensions.

The purpose of a computer animated film is to display the object(s) of analysis in a dynamic temporal setting. Scientific applications of this technique are beginning to see use in a large variety of areas since it is often far easier to display complicated spatiotemporal processes than to describe them either verbally or in mathematical terms. Uses of such a tool in a geographical setting are fundamentally twofold. Initially the film can be used as a cognitive device to aid the research person in perceiving the spatiotemporal dynamics of the process as represented by the patterns. Secondly, the film may be used as an heuristic device to aid in suggesting hypotheses which later may be tested in the data.

An example of this approach is a film which displays traffic crashes occurring in Washtenaw County, Michigan during the years of 1968–1970. Two scenes are displayed, collapsed real time and a composite week each representing different temporal frequencies as defined by the sampling theorem. Both scenes prove useful as a cognitive and hypothesis formulating device. The film is in color and of seven minutes duration.     

Suprathreshold intrinsic dynamics of the human visual system

Intrinsic high-frequency neural activities have been observed in the visual system of several species, but their functional significance for visual perception remains a fundamental puzzle in cognitive neuroscience. Spatiotemporal integration in the human visual system acts as a low-pass filter and makes the psychophysical observation of high-frequency activities very difficult. A computational model of retino-cortical dynamics (RECOD) is used to derive experimental paradigms that allow psychophysical studies of high-frequency neural activities. A reduced-parameter version of the model is used to quantitatively relate psychophysical data collected in two of these experimental paradigms. Statistical analysis shows that the model's account of the variance in the data is, in general, highly significant. We suggest that psychophysically measured oscillations reflect intrinsic neuronal oscillations observed in the visual cortex.     

Holocaust trauma reconstructed: Individual, familial, and social trauma.

Psychic trauma is characterized by ego damage, regression, and relative helplessness. Following a historic catastrophe, psychic trauma with ego damage is frequently encountered as cumulative trauma. Reconstruction was essential to the understanding of an adult patient initially unaware of his holocaust trauma. When the patient was a child, he and his parents were simultaneously traumatized. Intrapsychic intergenerational psychosocial and neurobiological factors were adverse codeterminants of his cumulative trauma. Isolated affects and fragmented memories required sequential connection in the context of family, identity, and society. Reconstruction importantly contributed to ego reintegration of a lost, lacerated childhood, and to adaptive mastery of trauma and conflict. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis, properties and application of four new 1;2 aluminium-complexed azo dyes

In view of the well-known environmental concerns associated with the synthesis and application of certain metal-complexed acid dyes, potentially less toxic analogues of four chromium and cobalt 1;2-complexed azo dyes were synthesised by employing aluminium in lieu of chromium or cobalt. The aluminium-complexed dyes produced brighter shades on nylon 6.6 and wool than the corresponding 1;2-complexed dyes based on chromium, cobalt and iron. The lightfastness results of nylon 6.6 and wool dyed with the 1;2 aluminium-complexed dyes were, in general, better than the unmetallised precursors, but inferior to the corresponding chromium, cobalt and iron dyes.     

Compression based clustering technique for enhancing accuracy in web scale videos

Multimedia Tools and Applications - Detection and clustering of commercial advertisements plays an important role in multimedia indexing also in the creation of personalized user content. In...