The derivation of the equations of moderately thick plates by the method of successive approximations

In this article the equations of a moderately thick plate are derived by the method of successive approximations. The derived equations exactly satisfy all the elastostatic equations, the plate equilibrium equations and traction free face boundary conditions.     

Experimental investigation and 3D finite element prediction of the heat affected zone during laser assisted machining of Ti6Al4V alloy

An experimental study was conducted to characterize the heat affected zone produced when laser heating a Ti6Al4V alloy plate workpiece. The emissivity and absorptivity of the Ti6Al4V alloy were determined experimentally. A 3D transient finite element method for a moving Gaussian laser heat source was developed to predict the depth and width of the heat affected zone on the Ti6Al4V alloy workpiece. There was a close correlation between the experimental data and the simulation results. It was found that the depth and width of the heat affected zone were strongly dependent on the laser parameters (laser power, laser scan speed, the angle of incidence and the diameter of the laser spot) and material properties (thermal conductivity, specific heat and density). Parametric studies showed that the depth and width of the heat affected zone increased with an increase in the laser power and decreased with an increase of the laser spot size and the laser scan speed. The thermal model can be used to determine the laser parameters for a given cut geometry that will yield no residual heat affected zone in the material after cutting. This provides the basis to optimize and improve laser assisted machining technique.     

Experimental behaviour of the reverse channel joint component at elevated and ambient temperatures

The reverse channel connection appears to have the best combination of desirable features under fire loading: moderate construction cost, ability to develop catenary action and extremely high ductility through deformation of the web channel (Ding and Wang, 2007). This paper presents the results of an experimental investigation of a reverse channel component conducted at the University of Coimbra as part of the European RFCS COMPFIRE Project, the main focus of which is to characterise the behaviour of steel joints that connect steel beams to concrete-filled tubular columns under natural fire loading. A series of tensile and compressive tests at ambient and elevated temperatures was conducted. The purposes of the experimental tests were to characterise the strength, stiffness and ductility of this joint component and to establish a relationship between force, displacement and temperature.     

Tenderness, ageing rate and meat quality of pork M. longissimus thoracis et lumborum after accelerated boning

The impact of accelerated boning on tenderness, ageing rate and meat quality of pork longissimus muscle was investigated. Accelerated boning of eight Large White×Landrace pork carcasses at 30 min post-mortem followed by chilling at 0°C resulted in tougher pork with higher drip loss and a darker surface lightness relative to conventional boning at 24 h post-mortem. The increased toughness was still observed at 4 days post-mortem, a time by which 80% of ageing generally had occurred as seen in experiment 2. The increased toughness could be attributed to cold shortening and a reduction in proteolysis.     

Detection and identification of aqueous saccharides by using surface-enhanced Raman spectroscopy

The sensitive detection and characterization of carbohydrates by means of a strategy based on surface-enhanced Raman spectroscopy is demonstrated. Spectra are obtained after injecting a small amount of saccharide solution onto a roughened silver substrate, with subsequent deposition of silver colloid. The sensitivity achieved by this two-step approach enables high-quality Raman spectra to be obtained for small amounts of aqueous saccharides (5 microL of a 10(-2) M solution) utilizing minimal laser power and small signal acquisition times (a few seconds). Spectral "fingerprints" obtained for seven structurally similar monosaccharides demonstrate clearly an effective means by which each sugar can be identified. The application to more complex analyses is demonstrated for monosaccharide mixtures and a disaccharide, whereby the SERS fingerprints aid in the determination of components.     

The relationship of ethnic identity and gender role attitudes to the development of career choice goals among black and Latina girls.

This study is a preliminary exploration of how individual differences in gender role attitudes and ethnic identity might be related to career decision self-efficacy and the gender traditionality of career choice goals in a sample of 102 9th-grade Black and Latina girls. Extending social-cognitive career theory, the authors examined 2 path models in which career decision self-efficacy mediated the effects of gender role attitudes and ethnic identity on the traditionality of the participants' career choice goals. Models depicting full and partial mediation were considered. The results of the path analyses provided confirmation for an extension of the social- cognitive career theory model, indicating that for this sample, career decision self-efficacy fully mediated the influence of egalitarian gender role attitudes and ethnic identity on gender traditionality in career choice goals. These findings offer support for consideration of the role of gender role attitudes and ethnic identity in career self-exploration and vocational guidance with Black and Latina girls. Limitations, implications for counseling, and suggestions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Being controlled by normative influences: Self-determination as a moderator of a normative feedback alcohol intervention.

The objectives of this research were to evaluate the efficacy of computer-delivered personalized normative feedback among heavy drinking college students and to evaluate controlled orientation as a moderator of intervention efficacy. Participants (N = 217) included primarily freshman and sophomore, heavy drinking students who were randomly assigned to receive or not to receive personalized normative feedback immediately following baseline assessment. Perceived norms, number of drinks per week, and alcohol-related problems were the main outcome measures. Controlled orientation was specified as a moderator. At 2-month follow-up, students who received normative feedback reported drinking fewer drinks per week than did students who did not receive feedback, and this reduction was mediated by changes in perceived norms. The intervention also reduced alcohol-related negative consequences among students who were higher in controlled orientation. These results provide further support for computer-delivered personalized normative feedback as an empirically supported brief intervention for heavy drinking college students, and they enhance the understanding of why and for whom normative feedback is effective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel application performance on shared high performance reconfigurable computing resources

The use of a network of shared, heterogeneous workstations each harboring a reconfigurable computing (RC) system offers high performance users an inexpensive platform for a wide range of computationally demanding problems. However, effectively using the full potential of these systems can be challenging without the knowledge of the system's performance characteristics. While some performance models exist for shared, heterogeneous workstations, none thus far account for the addition of RC systems. Our analytic performance model includes the effects of the reconfigurable device, application load imbalance, background user load, basic message passing communication, and processor heterogeneity. The methodology proves to be accurate in characterizing these effects for applications running on shared, homogeneous, and heterogeneous HPRC resources. The model error in all cases was found to be less than 5% for application runtimes greater than 30 s, and less than 15% for runtimes less than 30 s.     

High-pressure liquid chromatography fingerprinting of petroleums and petroleum products

Combined GC/HPLC fingerprinting of petroleums and process streams derived therefrom gives detailed information on their constituents. The silica gel-heptane system affords separation into classes of hydrocarbons which, together with dual u.v. and R.I. modes of detection, gives abundant information on the composition of such samples. GC on a medium-efficiency SCOT column is used as a complementary technique only. Interpretations of HPLC chromatograms for samples ranging from gasolines to bitumens are given.