Verification of Articulated Arm Coordinate Measuring Machines Accuracy Using LaserTracer System as Standard of Length

This article describes a novel approach to verification of articulated arm coordinate measuring machines (AA CMMs) based on ISO 10360-2 standard. The approach utilizes the LaserTracer (LT) system as standard of length and automation of calibration procedure using an industrial robot. In this method, the robot is programmed to repeatedly move the AA CMM. The retroreflector is integrated with the stylus of AA CMM. Location of the retroreflector is constantly tracked by LaserTracer and, in select positions, the measurements of distance are performed by both the AA CMM and LT system. The verification of AA CMM accuracy is carried out through the comparison of the two measurement values. The developed procedure is recommended mainly for checking AA CMMs with large measuring volume, where the application of common artefacts is usually insufficient, or time-consuming, due to the fact that measurements have to be performed for several subspaces in the AA CMM measuring volume.     

Economic production quantity (EPQ) model with partial backordering and a discount for imperfect quality batches

Economic production quantity (EPQ) models are traditionally used in operations management. Despite the large number of papers that describe the models, the classic EPQ model does not consider either imperfect quality batches or shortages. However, some industries may be able to sell imperfect items for a lower price, reducing the total production cost. This paper proposes an EPQ model with partial backordering and discount for imperfect quality batches and an algorithm that returns optimal values for the problem. From a numerical example, it is possible to analyse how the changes in the variables affect each part of the total cost function, which provides a useful tool for strategic decision-making. We conclude that it is better to sell imperfect items as soon as possible because the savings in holding costs results in a total cost reduction. It is more profitable for the producer to have planned shortages considering that some costumers are willing to wait. Furthermore, the reduction of the goodwill cost does not necessarily reduce the total cost.     

Proton microbeam irradiation effects on PtBA polymer

Proton beam lithography has made it possible to make various types of 3D-structures in polymers. Usually PMMA, SU-8, PS polymers have been used as resist materials for lithographic purpose. Microbeam irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 20 MeV proton microbeam are reported. Preliminary results on pattern formation on PtBA are carried out as a function of fluence. After writing the pattern, a thin layer of Ge is deposited. Distribution of Ge in pristine and ion beam patterned surface of PtBA polymer is studied using the optical and secondary electron microscopic experimental methods.     

Hydration of Non-electrolytes in H<Subscript>2</Subscript>O and D<Subscript>2</Subscript>O Investigated by Passynski’s Method

Passynski’s hydration numbers were calculated for 1-propanol, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,6-dimethylpyridine, and 2,4, 6-trimethylpyridine in H₂O and D₂O, for the temperature range from 277K to 313 K. Correlations between the hydration numbers and the association energies of 1:1 water–amine complexes as well as the net atomic charges on the nitrogen atom were found. It seems probable that the O–H· · ·N bond promotes the structure due to the strengthening of the O–H· · ·O bonds between water molecules neighboring that of amine. The higher the O–H· · ·N bond energy, the stronger is the promoting effect. The calculated hydration numbers in H₂O are lower than their counterparts in D₂O. ThusD₂O appears more sensitive than H₂O to the solute-induced changes of structure.     

A simple semi sol-gel method for preparation of alumina monoliths with hierarchical pore structures

A simple semi sol-gel method for preparation of stable alumina monoliths is presented. The approach is based on chemical binding of boehmite by hydrolysis products of aluminium nitrate. The crystalline phase of the monoliths depends on the calcination temperature, and the size and shape of the alumina crystallites were determined by transmission electron microscopy and modelling of X-ray diffraction patterns. The monoliths have bimodal pore size distributions with mesopores ranging from 3 to 20 nm and macropores ranging from 10 to 40 μm. Incipient wetness impregnation resulted in gold particles, ranging from 4 to 20 nm, supported on the monoliths. The size of the gold particles depended largely on the crystalline phase of the support, but also on the amount of gold precursor. The catalytic activity of the functionalised materials in liquid-phase oxidation of glucose was higher in continuously stirred batch reactor tests compared to continuous flow fix bed tests. In both cases the activity was improved as the size of gold particles decreased.     

The role of learned irrelevance in attentional set-shifting impairments in Parkinson's disease.

In this study, the cognitive and neurochemical factors underlying learned irrelevance, one of the mechanisms thought to be responsible for attentional set-shifting deficits in Parkinson's disease (PD), were investigated. In a visual discrimination learning task, the extent to which a target dimension was irrelevant prior to an extra-dimensional shift was varied. Twenty patients with PD and 22 healthy participants performed the task twice, with patients tested on and off L-dopa. The patients made more errors than control participants in the condition in which the target dimension was completely irrelevant prior to the extradimensional shift, but not when it was partially reinforced. Moreover, L-dopa had no effect on the patients' task performance, despite improving their working memory. These results confirm that learned irrelevance is a significant factor in accounting for attentional set-shifting deficits in patients with PD, although unlike other executive impairments in this group, the phenomenon appears to be unrelated to their central dopaminergic deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association in Dilute Aqueous Solution of Pyridine and Its Methyl Derivatives Studied by Cryoscopic Method

Pyridine and its methyl derivatives form complexes with water due to hydrogen bonds. The co-operative nature of the hydrogen bonds leads to the association of the complexes and to various modes of hydration. The degrees of association of monohydrate complexes have been calculated for liquid dilute aqueous solutions of pyridine, 2-, 3-, 4-methylpyridine, and 2,6-dimethylpyridine at temperatures from 273 K to 268.5 K. The association number increases with an increase of the amine concentration. Positive correlation was found between the degree of association of the 1:1 water–amine complexes and the size of microheterogeneities. It was shown that the mechanics of this process involves hydrogen bonding and van der Waals interactions.     

Structure of anxiety symptoms in urban children: Competing factor models of Revised Children's Manifest Anxiety Scale.

The Revised Children's Manifest Anxiety Scale (RCMAS; C. R. Reynolds & B. 0. Richmond, 1985) is among the most widely used self-report measures of children's anxiety. The authors compared its current empirically derived factor structure with theory-driven models derived from 8 experts on child anxiety using concept mapping. Confirmatory factor analyses compared models using data from 898 seventh graders in an urban public school system serving a high percentage of African Americans. The most parsimonious best-fitting model was an expert-derived model with factors reflecting anxious arousal, social evaluation–oversensitivity, worry, and a higher order factor. This model was theoretically meaningful, excluded items less relevant to anxiety, and was invariant across gender. Future research with the RCMAS should consider use of these dimensions. The combination of qualitative and quantitative methodology used in this study appeared to have considerable utility for refining measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)