Shear resistance in stainless steel plate girders with transverse and longitudinal stiffening

This paper summarizes and presents main results of the investigation conducted in the Department of Construction Engineering of the UPC dealing with shear behaviour of stainless steel plate girders. Initial shear buckling stress together with ultimate shear capacity of these structural elements have been evaluated with special attention paid to the effect of including stiffeners, both transverse and longitudinal. The studies conducted, both numerical and experimental tests, have permitted the development of new and simple design expressions to determine more accurately the initial shear buckling stress in stainless steel web panels and the ultimate capacity of plate girders considering the presence of a rigid or non-rigid end post.     

Texture formation on the friction surface in transformation-toughened ceramics

The surface of Y-TZP ceramics after dry friction on steel in a wide range of relative sliding velocities (0.2–11.1 m/s) was studied by X-ray diffraction. An analysis of the surface structure showed that the texture state of the friction surface is similar to that observed for analogous materials upon rough grinding. The main trends in the I ₍₀₀₂₎/I ₍₂₀₀₎ intensity ratio characterizing the tetragonal ZrO₂ phase as a function of the sliding velocity and the ceramic grain size are established. The mechanisms of lattice reorientation operative at various sliding velocities are discussed.     

Pioneers in Partnership: Lesbian and Gay Male Couples in Civil Unions Compared With Those Not in Civil Unions and Married Heterosexual Siblings.

This study compared 212 lesbians and 123 gay men who had civil unions in Vermont (during the first year legislation made this available) with 166 lesbians and 72 gay men in their friendship network who had not had civil unions, and also with 219 heterosexual married women and 193 heterosexual married men consisting of civil union couples' siblings and their spouses. Married heterosexual couples had been together longer and had more traditional division of labor and child care than did lesbians and gay men in both types of couples. Lesbians in civil unions were more open about their sexual orientation than those not in civil unions, and gay men in civil unions were closer to their family of origin than gay men not in civil unions. This is the first study on same-sex couples with civil unions, and the first to compare lesbians and gay men with their married siblings. At a time of legal changes for same-sex couples, these results indicate that legalized same-sex relationships are related to visibility of same-sex couples to their family and the general public. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Damping of the mechanical vibrations of a piezoelectric element by sensitive coatings

A method of calculating the viscoelastic properties of moisture-sensitive polymer films deposited on the piezoelectric element of a quartz resonator is proposed.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 60, No. 6, pp. 994–999, June, 1991.     

Long-Term Memory Deficits in Schizophrenia: Primary or Secondary Dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classification of radar signatures by autoregressive model fittingand cluster analysis

Ninety radar signatures were digitally recorded during the probing of ten different land and marine objects with a pulsed coherent Doppler radar. Their spectra were evaluated on the basis of the Marple algorithm for autoregressive model fitting. An attempt at classification is made. The method consists in representing the radar signatures as points in four-dimensional space and identifying the obtained clusters of four-dimensional points with the observed objects. The cluster analysis is carried out assuming that the classification parameters have different clustering lengths     

Production and Heat Treatment of Yarn from Copolyamide Based on Poly-(p-Phenylene Terephthalamide)

Fibres made of an aromatic rigid-chain copolyamide based on PPTA were manufactured by spinning through an air gap from liquid-crystalline sulfuric-acid solutions. In heat treatment under tension, marked structural changes take place in Armalon copolymeric fibres which significantly increase their strength and modulus of elasticity.     

Energy transfer and compatibility analysis of PVK/MEH-PPV blends processed via electrospraying and electrospinning

Solution polymer blends of a high molecular weight and a low molecular weight poly(9-vinyl carbazole) PVK with poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), at a fixed blend ratio of 95.5:0.5, were processed via electrospraying and electrospinning. SEM studies revealed that electrosprayed particles were produced when low molecular weight PVK was used, while electrospun fibers were successfully obtained from solutions containing high molecular weight PVK, over a concentration range of 4–10% (w/v). From the absorption spectra of the neat polymers it was determined that Urbach energy E_u increase and optical band gap E_g decreases due to the physical defects along the main chain introduced by these electrostatic processing methods. Photoluminescence spectroscopy revealed a particular applied voltage, which depends on concentration and molecular weight, where aggregation of PVK levels off. Luminescence quenching of MEH-PPV is also observed to increase with applied voltage consistent with possible energy transfer from shorter conjugation length segments to nearby longer conjugated segments. The ratio of the intensity of the excitation spectra of the PVK (donor, both PVK_L or PVK_H) and the MEH-PPV (acceptor), I_D/I_A, exhibited minima at this particular voltage and then levels off, indicating not only maximum interpenetration and thus compatibility of both polymers but also maximum energy transfer. Hence, we demonstrate that compatibility and energy transfer can be optimized varying concentration and applied voltage during both electrospraying and electrospinning processes.