Conceptual design and modification of freeform surfaces using dual shape representations in augmented reality environments

This paper enables the rapid creation and modification of freeform surfaces inside an augmented reality environment, and focuses on methods for enabling increased flexibility during exploratory, conceptual industrial product design through three-dimensional (3D) sketch-based user input. Specifically, we address the role of multiple shape representations with varying uncertainty levels during 3D conceptual sketching, along with methods to transform between those representations. The main contributions of this work are: (1) the formulation of virtual shape data in multiple, concurrent representations (points and surfaces), and a regression method to transition fluidly back and forth between these representations during design, (2) methods for deforming and exploring the product shape using these multiple representations, and (3) representations of these forms such that designers can explore conceptual designs without the need for detailed surface operations such as trimming or continuity enforcement. Through incorporating these contributions, we introduce techniques that can be incorporated in future computer-aided conceptual design systems. These contributions are demonstrated for freeform surface design, with examples of computer mouse and car seat exterior surfaces.     

A conducting composite of polypyrrole with ultrahigh molecular weight polyethylene foam

Through a chemical polymerization of pyrrole inside ultrahigh molecular weight polyethylene (UHMWPE) foam, a conducting polymer composite was obtained. To produce conductive polymer foams, successive imbibiting of reactives, FeCl₃ and pyrrole in tetrahydrofuran solutions, were carried out. The conductive polymeric materials were characterized by FTIR, DSC, and SEM. Mechanical property measurements were carried out on the films prepared by the compression molding of the conductive foam polymers. These films showed rather high tensile strength compared to pure UHMWPE. Conductivity determined by a two‐probe technique showed that it increased with the pyrrole content in the UHMWPE foam matrix. The compression molding, however, resulted in a considerable reduction in the conductivities. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1843–1850, 1999     

A conducting composite of polythiophene: synthesis and characterization

Conducting polymer composites of polythiophene, using a polyamide as the insulating matrix, were prepared via electrochemical methods. The characterization of the composite was done by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared and pyrolysis studies. The conductivities were measured by a four-probe technique. The cited methods revealed that the composites have properties different from those of simple mechanical mixtures of the two polymers.     

Investigating Fatty Acid Composition of Samples were Homogenized Various Meat and Offal Products from Turkey

The aim of the present study was to compare the fatty acid composition, PUFA:SFA ratio, n6/n3 ratio, and TFA of different farm animal meats and offal products. These products were collected at a regional farm in Istanbul which is the most populous city in Turkey. The results of fatty acid composition analysis indicated that the major fatty acids of C16:0 (18.00–29.35 %), C18:0 (4.10–29.71 %), C18:1 (29.21–57.30 %), and C18:2 (1.37–18.60 %) were found in the samples. The total saturated fatty acids, total monounsaturated fatty acids and total polyunsaturated fatty acids content of the samples ranged between 30.00 and 61.83 %, 32.24 and 57.80 %, and 1.64 and 23.60 %, respectively (p < 0.05). Except for turkey abdominal fat, TFA content in all other samples showed a variation between 0.10 and 3.36 %. The PUFA:SFA ratio was higher in turkey meat (0.64) and was lower in sheep kidney fat (0.02). Moreover, the n6/n3 PUFA ratio changed between 2.90 and 22.28 (p < 0.05).     

Sorption of boron by invasive marine seaweed: Caulerpa racemosa var. cylindracea

The sorption of boron from aqueous solution onto Caulerpa racemosa var. cylindracea (CRC), collected from Seferihisar/Izmir region in Turkey, was investigated as a function of pH, temperature, initial boron concentration, adsorbent dosage, contact time and ionic strength. Optimum conditions for the sorption of boron were obtained at pH 7.5, 318 K, 8 mg L⁻¹ initial boron concentration, 0.2 g of CRC, 2.5 h contact time and greater ionic strength (10⁻¹ M NaCl). As the temperature was increased the boron removal took place with higher percentages. In experiments conducted at optimum conditions, maximum boron sorption was determined to be about 63%. The experimental data were analyzed by Freundlich, Langmuir and Dubinin–Radusckevich (DR) equations. Freundlich and DR models provide best conformity with the experimental data. In order to describe kinetics of boron sorption onto CRC, first-order Lagergren equation, pseudo-second-order kinetic model and intraparticle diffusion model were used. It was seen that the first order Lagergren equation was better described than the pseudo-second-order kinetic model. Thermodynamic parameters of sorption process were also calculated. It was obtained that sorption process was not spontaneous. The characterization of CRC was carried out by Fourier transform infrared spectroscopy (FTIR) analysis.     

Item response theory analysis of diagnostic criteria for alcohol and cannabis use disorders in adolescents: Implications for DSM-V.

Item response theory (IRT) has advantages over classical test theory in evaluating diagnostic criteria. In this study, the authors used IRT to characterize the psychometric properties of Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV; American Psychiatric Association, 1994) alcohol and cannabis use disorder symptoms among 472 clinical adolescents. For both substances, DSM-IV symptoms fit a model specifying a unidimensional latent trait of problem severity. Threshold (severity) parameters did not distinguish abuse and dependence symptoms. Abuse symptoms of legal problems and hazardous use, and dependence symptoms of tolerance, unsuccessful attempts to quit, and physical-psychological problems, showed relatively poor discrimination of problem severity. There were gender differences in thresholds for hazardous use, legal problems, and physical-psychological problems. The results illustrate limitations of DSM-IV criteria for alcohol and cannabis use disorders when applied to adolescents. The development process for the fifth edition (DSM-V) should be informed by statistical models such as those used in this study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Epidemiological comparisons of problems and positive qualities reported by adolescents in 24 countries.

In this study, the authors compared ratings of behavioral and emotional problems and positive qualities on the Youth Self-Report (T. M. Achenbach & L. A. Rescorla, 2001) by adolescents in general population samples from 24 countries (N = 27,206). For problem scales, country effect sizes (ESs) ranged from 3% to 9%, whereas those for gender and age ranged from less than 1% to 2%. Scores were significantly higher for girls than for boys on Internalizing Problems and significantly higher for boys than for girls on Externalizing Problems. Bicountry correlations for mean problem item scores averaged .69. For Total Problems, 17 of 24 countries scored within one standard deviation of the overall mean of 35.3. In the 19 countries for which parent ratings were also available, the mean of 20.5 for parent ratings was far lower than the self-report mean of 34.0 in the same 19 countries (d = 2.5). Results indicate considerable consistency across 24 countries in adolescents' self-reported problems but less consistency for positive qualities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions among metastable pits on heterogeneous electrodes

A previously developed spatiotemporal model of the interactions among metastable pits on homogeneous electrodes is extended to heterogeneous surfaces with randomly distributed inclusion sites in an otherwise passive electrode. The inclusions are treated as favored sites for pit initiation events. The effect of the spatial density of inclusions on susceptibility to explosive growth in pitting corrosion is investigated. It is shown that there exist critical values of the pit density for the explosive growth of metastable pits that leads to a transition to pitting corrosion. Convective mass transport is shown to alter the density required for explosive growth. The effect of a limitation on the number of times that an inclusion can initiate a pit on the transition to the pitting corrosion is also considered.     

The solubility of apricot kernel oil in supercritical carbon dioxide

The solubility of kernel oil from apricots (Prunus armeniaca L.) in supercritical carbon dioxide at 313.15, 323.15 and 333.15 K and at 15, 30, 45, 52.5 and 60 MPa was determined. Appropriate models were fitted to the data and the crossover pressure of apricot kernel oil was found to be between 20 and 30 MPa. Crossover pressure is a pressure value at which the effect of temperature on the solubility changes. Solubility increased as the temperature increased above the crossover pressure but decreased when temperature increased below the crossover pressure. It increased with an increase in pressure over all of the temperature range. The solubility data were well represented by models based on density but the best was found to be the Adachi & Lu equation. An empirical model that did not require density data for CO₂ was proposed to relate solubility to temperature and pressure and it was found equally successful to the Adachi & Lu equation.