Five supramolecular compounds of water-soluble sulfonylcalix[4]arenetetrasulfonate showing two calixarene conformations

Five new compounds of sulfonylcalix[4]arenetetrasulfonate (SC4AS), [H7Na(H2O)(3)(SC4AS)(phen)(5)](H2O)(11.9) (1), [H6Mn(H2O)(4)(SC4AS)(phen)(5)] (H2O)(12.7) (2), [Cu-4(SC4AS) (phen)(6)] (H2O)(4.5) (3), {[Cu (2)(SC4AS) (bpy)(2)][Cu(bpy)(2)(H2O)](2)} (H2O)(6.6) (4), and {[Zn-2(SC4AS) (phen)(2)][Zn(phen)(2)(H2O)(2)](2)} (H2O)(7) (5) (where phen 1,10-phenanthroline and bpy = 2,2'-bipyridine), were synthesized by a hydrothermal method and structurally determined by single crystal X-ray diffraction. The SC4AS ligand adopts partial cone conformation in compounds 1 and 2 and 1,2-alternate form in compounds 3-5. According to the structural analysis and density functional theory (DFT) calculations, we suggest that the metal can affect the conformation of SC4AS.

Influence of imperfect interfaces on bending and vibration of laminated composite shells

This paper is devoted to modeling elastic behavior of laminated composite shells, with special emphasis on incorporating interfacial imperfection. The conditions of imposing traction continuity and displacement jump across each interface are used to model imperfect interfaces. Vanishing transverse shear stresses on two free surfaces of a shell eliminate the need for shear correction factors. A linear theory underlying elastostatics and kinetics of laminated composite shells in a general configuration is presented from Hamilton's principle. In the special case of vanishing interfacial parameters, this theory reduces to the conventional third-order zigzag theory for perfectly bonded laminated shells. Numerical results for bending and vibration problems of laminated circular cylindrical panels are tabulated and plotted to indicate the influence of the interfacial imperfection. (C) 2000 Elsevier Science Ltd. All rights reserved.

Deinstitutionalization and its Effects on Social Inclusion, Choice-Making, Adaptive and Maladaptive Behavior for Individuals with Intellectual Disabilities: Case Studies Analysis

In the past three decades institutions for persons with intellectual disabilities (ID) have been downsizing and closing in Ontario, Canada. This trend is reflective of the changes that have occurred in society. As of March 2009 the last institution operated by the Ontario government for persons with ID closed, placing the remaining approximately 1000 persons into the community. The current study was an analysis of part of one study in a four-study research project, called the Facilities Initiative Study, to explore the impact of the closures on the lives of individuals who have been reintegrated into community settings. The goal of the current case study analysis was to describe the impact of changes in social inclusion, choice-making/autonomy, and adaptive/maladaptive functioning of four individuals prior to and following transition to the community. The results suggested that, in most cases, community integration was related to more social inclusion opportunities and autonomy in choice-making, a wider range of adaptive behaviors and fewer maladaptive behaviors. In some cases, the evidence suggested that some of these indices of quality of life were not improving. Overall, the study found that the differences observed were unique to each of the individuals who participated in the case study analysis. Some generalized themes were generated that can be applied to future deinstitutionalization endeavors.

Experimental studies of the shear behavior and strength of LiteSteel beams with stiffened web openings

Abstract: LiteSteel beam (LSB) is a new cold-formed steel hollow flange channel section produced using a patented manufacturing process. It is commonly used as flexural members in residential, industrial and commercial buildings. Current practice in flooring systems is to include openings in the web element of floor joists or bearers so that building services can be located within them. Test results have shown that the shear capacity of LSBs can be reduced considerably by the inclusion of web openings. A cost effective method of eliminating the detrimental effects of a large web opening is to attach suitable stiffeners around the web openings of LSBs. A detailed experimental study consisting of 17 shear tests was therefore undertaken to investigate the shear behaviour and strength of LSBs with stiffened circular web openings. Both plate and stud stiffeners with varying sizes and thicknesses were attached to the web elements of LSBs using a number of screw-fastening arrangements in order to develop a suitable stiffening arrangement for LSBs. Simply supported test specimens of LSBs with an aspect ratio of 1.5 were loaded at mid-span until failure. This paper presents the details of this experimental study of LSBs with stiffened web openings, and the results of their shear capacities and associated behavioural characteristics. Suitable screw-fastened plate stiffener arrangements have been recommended in order to restore the original shear capacity of LSBs.

Inclusion of tapered tubes in enhancing the crash performance of automotive frontal structures

This paper treats the design and analysis of an energy absorbing system. Experimental tests were conducted on a prototype, and these tests were used to validate a finite element model of the system. The model was then used to analyze the response of the system under dynamic impact loading. The response was compared with that of a similar system consisting of straight circular tubes, empty and foam-filled conical tubes. Three types of such supplementary devices were included in the energy absorbing system to examine the crush behavior and energy absorption capacity when subjected to axial and oblique impact loadings. The findings were used to develop design guidelines and recommendations for the implementation of tapered tubes in energy absorbing systems. To this end, the system was conceptual in form such that it could be adopted for a variety of applications. Nevertheless, for convenience, the approach in this study is to treat the system as a demonstrator car bumper system used to absorb impact energy during minor frontal collisions.

Deformational Behavior of Fiber-Reinforced Concrete Beams in Bending

An experimental study aimed at understanding the deformational behavior of conventionally reinforced steel fiber concrete beams in pure bending is reported in this paper. One group of beams has steel fibers dispersed in the entire volume of the beam and the second has fibers dispersed over half the depth of the beam on the tension side. A comparative study of the deformational characteristics of these beams has been made. Half-depth fiber inclusion, requiring only half the quantity of fibers of full-depth inclusion, is found to be equally effective in improving the deformational behavior of beams. Thus, by such modes of inclusion of fibers, an economical and efficient use of expensive steel fibers can be realized.

The electrical switching and thermal behavior of bulk Ge(15)Te(85-x)Sn(x) and Ge(17)Te(83-x)Sn(x) glasses

Bulk Ge(15)Te(85 - x)Sn(x) and Ge(17)Te(83 - x)Sn(x) glasses, are found to exhibit memory type electrical switching. The switching voltages (V(t)) and thermal stability of Ge(15)Te(85 - x)Sn(x) and Ge(17)Te(83 - x)Sn(x) glasses are found to decrease with Sn content. The composition dependence of v, has been understood on the basis of the decrease in the OFF state resistance and thermal stability of these glasses with tin addition. X-ray diffraction studies reveal that no elemental Sn or Sn compounds with Te or Ge are present in thermally crystallized Ge-Te-Sn samples. This indicates that Sn atoms do not interact with the host matrix and form a phase separated network of its own, which remains in the parent glass matrix as an inclusion. Consequently, there is no enhancement of network connectivity and rigidity. The thickness dependence of switching voltages of Ge(15)Te(85 - x)Sn(x) and Ge(17)Te(83 - x)Sn(x) glasses is found to be linear, in agreement with the memory switching behavior shown by these glasses. (C) 2011 Elsevier B.V. All rights reserved.

Plastic constitutive behavior of short-fiber/particle reinforced composites

A cylindrical cell model based on continuum theory for plastic constitutive behavior of short-fiber/particle reinforced composites is proposed. The composite is idealized as uniformly distributed periodic arrays of aligned cells, and each cell consists of a cylindrical inclusion surrounded by a plastically deforming matrix. In the analysis, the non-uniform deformation field of the cell is decomposed into the sum of the first order approximate field and the trial additional deformation field. The precise deformation field are determined based on the minimum strain energy principle. Systematic calculation results are presented for the influence of reinforcement volume fraction and shape on the overall mechanical behavior of the composites. The results are in good agreement with the existing finite element analyses and the experimental results. This paper attempts to stimulate the work to get the analytical constitutive relation of short-fiber/particle reinforced composites.

Effect of phase-transformation on mechanical-behavior of dual-phase steel plate

The mechanical behavior of dual phase steel plates is affected by internal stresses created during martensite transformation. Analytical modelling of this effect is made by considering a unit cell made of martensite inclusion in a ferrite matrix. A large strain finite element analysis is then performed to obtain the plane stress deformation state. Displayed numerically are the development of the plastic zone and distribution of local state of stress and strain. Studied also are the shape configuration of the martensite (hard-phase) that influences the interfacial condition as related to stress transmission and damage. Internal stresses are found to enhance the global flow stress after yield initiation in the ferrite matrix. Good agreement is obtained between the analytical results and experimental observations.

Experimental investigation of Very-High-Cycle Fatigue behavior for a structural steel

Very-High-Cycle Fatigue (VHCF) test for a medium carbon structural steel (40Cr) has been performed and a stepwise S-N curve was obtained by employing cantilever-type rotary bending fatigue machine with hourglass shape specimen. The S-N curve was well explained as a combination of curves for surface-induced fracture and interior inclusion-induced fracture with fish-eye patterns. The morphology of the fish-eye pattern was illustrated in order to clarify subsurface crack initiation and propagation behavior.

Formation of self-assembled monolayers on gold electrodes with inclusion complexes of cyclodextrins and viologens

A novel kind of electroactive self-assembled monolayer (SAM) has been successfully prepared through the following procedure: (1) formation of inclusion complexes (denoted as CD/C8VC10SH) between N-(n-octyl)-N'-(10-mercaptodecyl)-4,4'-bipyridinium dibromide (C8VC10SH) and alpha-, beta-cyclodextrin (CD) under a mild condition; (2) spontaneous formation of SAM of CD/C8VC10SH on gold electrodes at room temperature. High-resolution H-1-NMR spectrum was used to confirm the formation of CD/C8VC10SH. Cyclic voltammetry was used to characterize the redox behavior of the resulting monolayers and chronoamperometry and electrochemical impedance spectroscopy to characterize their electron transfer kinetics. It was found that the redox sites in SAM of CD/C8VC10SH are effectively diluted, with a larger electron transfer rate constant than that of SAM of C8VC10SH.

Use and access to ICT in students of public secondary schools in Chihuahua City, Mexico: inclusion in teaching and digital literacy

This paper addresses the issue of the digital divide in students of public secondary schools at Chihuahua City, Mexico. It seeks to identify potential inequality of opportunities with regards to subjects’ access to information, knowledge and education through the ICT (internet, mobile telephony, broadband and television). The study takes three schools as investigative stage, using the survey as a data collection instrument, identifying patterns of behavior regarding: general knowledge of them, access to computer equipment and internet, and characterization of their use. Other aspects of analysis are the identification of the educational level of parents and access to technology resources available for academic and non-academic purposes in various application areas (home, school and social environment). The proposal concludes, that it is through the recollection of alternatives suggested by the teachers themselves to incorporate ICT for teaching purposes in a systematic and planned fashion, whose greatest reflection manifests in better digital literacy indicators.

An evaluation of the effect of altering nutrition and nutritional strategies in early lactation on reproductive performance and estrous behavior of high-yielding Holstein-Friesian dairy cows

Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170 g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (+/- 10 MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140 g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40 g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception rate to first insemination. However, conception rate to second insemination, 100-d pregnancy rate (from the commencement of breeding), and overall pregnancy rate tended to be higher in this group. The high-starch/high-fat treatment tended to decrease the proportion of delayed ovulations and increase the proportion of animals cycling by d 50 postcalving. Animals that failed to conceive to first insemination had a significantly longer luteal phase in the first cycle postpartum and a longer inter-ovulatory interval in the second cycle postpartum. With regards to estrous behavior, results indicate that as the size of the sexually active group increased, the intensity of estrus and the expression of mounting or attempting to mount another cow also increased. Furthermore, cows that became pregnant displayed more intense estrous behavior than cows that failed to become pregnant.

Optimized process for the inclusion of carbon nanotubes in elastomers with improved thermal and mechanical properties

The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile-butadiene rubber (HNBR) matrix on the mechanical, dynamic viscoelastic, and permeability properties were studied in this investigation. Different techniques of incorporating nanotubes in HNBR were investigated in this research. The techniques considered were more suitable for industrial preparation of rubber composites. The nanotubes were modified with different surfactants and dispersion agents to improve the compatibility and adhesion of nanotubes on the HNBR matrix. The effects of the surface modification of the nanotubes on various properties were examined in detail. The amount of CNTs was varied from 2.5 to 10 phr in different formulations prepared to identify the optimum CNT levels. A detailed analysis was made to investigate the morphological structure and mechanical behavior at room temperature. The viscoelastic behavior of the nanotube filler elastomer was studied by dynamic mechanical thermal analysis (DMTA). Morphological analysis indicated a very good dispersion of the CNTs for a low nanotube loading of 3.5 phr. A significant improvement in the mechanical properties was observed with the addition of nanotubes. DMTA studies revealed an increase in the storage modulus and a reduction in the glass-transition temperature after the incorporation of the nanotubes. Further, the HNBR/CNT nanocomposites were subjected to permeability studies. The studies showed a significant reduction in the permeability of nitrogen gas. Copyright © 2011 Wiley Periodicals, Inc.

Élaboration et validation empirique d'un modèle de consultation individuelle auprès des enseignants afin de favoriser l'inclusion scolaire des enfants ayant un TDAH

Les interventions proactives ou comportementales en classe sont reconnues empiriquement pour leur efficacité à améliorer le comportement ou le rendement scolaire des enfants ayant un TDAH (DuPaul & Eckert, 1997; Hoza, Kaiser, & Hurt, 2008; Pelham & Fabiano, 2008; Zentall, 2005). Or, l’écart entre les interventions probantes et celles retrouvées dans le milieu général de l’éducation souligne l’importance de répliquer les résultats d’études obtenus dans un environnement contrôlé dans un format de livraison réaliste. L’objectif principal de cette thèse est d’élaborer et d’évaluer un programme de consultation individuelle (PCI) fondé sur une démarche de résolution de problème et d’évaluation fonctionnelle, pour soutenir les enseignants du primaire dans la planification et la mise en œuvre cohérente des interventions privilégiées pour aider les enfants ayant un TDAH. D’abord, une recension des principales modalités d’intervention auprès des enfants ayant un TDAH est effectuée afin d’identifier les interventions à inclure lors du développement du programme. Par la suite, des solutions favorisant le transfert des interventions probantes à la classe ordinaire sont détaillées par la proposition du PCI ayant lieu entre un intervenant psychosocial et l’enseignant. Enfin, l’évaluation du PCI auprès de trente-sept paires enfant-enseignant est présentée. Tous les enfants ont un diagnostic de TDAH et prennent une médication (M). Les parents de certains enfants ont participé à un programme d’entraînement aux habiletés parentales (PEHP). L’échantillon final est: M (n = 4), M et PEHP (n = 11), M et PCI (n = 11), M, PEHP et PCI (n = 11). Les résultats confirment l’efficacité du PCI au-delà de M et M + PEHP pour éviter une aggravation des comportements inappropriés et améliorer le rendement scolaire des enfants ayant un TDAH. Par ailleurs, une augmentation de l’utilisation des stratégies efficaces par l’enseignant est observable lorsqu’il a à la fois participé au PCI et reçu une formation continue sur le TDAH en cours d’emploi. Les implications cliniques de l’intervention pour l’enfant ayant un TDAH et son enseignant de classe ordinaire sont discutées.