Effect of Ba(Ti<Subscript>(0.9)</Subscript>Sn<Subscript>0.1</Subscript>)O<Subscript>3</Subscript> ceramic doping on optical,thermal and dielectric properties of polycarbonate host

Ba(Ti_(0.9)Sn_0.1)O₃ (BTS) ceramic was prepared by a conventional ceramic processing. BTS-polycarbonate (PC) composites were prepared at different BTS concentrations by weight in order to study their optical and dielectric properties. The absorption coefficient (α) was determined in the wavelength range from 250–600 nm at room temperature for all BTS-PC composites. The optical gap (E _opt) was also determined for BTS-PC composites. The variation of the absorption coefficient (α) and optical gap (E _opt) with BTS content are reported. It was found that BTS ceramic highly enhances the UV absorption of PC host at 300 nm. The optical gap decreases up to the value of 3.93 eV as BTS content increases up to 35 wt% and this was attributed to the formation of localized states in the forbidden gap. The relative dielectric permittivity, dielectric loss and loss tangent were measured at temperature range from room temperature up to 150°C and at frequency values 1 kHz, 10 kHz and 50 kHz. Addition of BTS to PC host, however, will increase relative dielectric permittivity, dielectric loss and loss tangent. Besides, increasing of temperature will also increase relative dielectric permittivity, dielectric loss and loss tangent especially above the glass transition temperature of PC host and this behaviour was attributed to the segmental motion of polymer chains. On the other hand, this study shows that there is a good agreement between SEM, DSC and dielectric results and also between optical gap and a.c. conductivity results. Moreover, SEM and DSC results reveal that addition of BTS ceramic particles to PC host will reduce the physical bond between polymer chains or may be will increase the free volume in the polymer host and consequently will enhance the segmental motion of polymer chains and this behaviour is independent of ceramic phase.     

Ensuring that potential Gulf farmland investments in developing countries are pro-poor and sustainable

This paper provides an overview of Gulf investments in foreign farmland, mainly in developing countries, and the motivation behind these investments. The literature suggests that private entities in Gulf countries are engaging in these investments for portfolio diversification, while Gulf governments are investing to ensure food security challenges resulting from the limited agricultural resources of these countries. The paper also discusses examples of farmland investments in Sudan, Indonesia and Pakistan, and their consequences. The main recommendation is the need to ensure that these investments provide positive externalities to the host countries and local communities involved, in order to ensure the continuity and acceptability of these investments.     

The sense of entitlement in romantic relationships—Scale construction, factor structure, construct validity, and its associations with attachment orientations.

Based on clinical evidence and theoretical writings that pointed to the importance and uniqueness of the sense of entitlement in couple relationships, two studies were designed to develop and validate the Sense of Relational Entitlement (SRE) scale. A factor analysis performed on the scale's items yielded five factors that identified three basic entitlement-related attitudes toward a romantic partner. Findings indicated that both exaggerated and restricted forms of relational entitlement seem to be maladaptive and put people at risk for emotional problems. Findings also indicated that excessive and restricted forms of relational entitlement were significantly associated with attachment insecurities. In addition, the SRE scale was found to tap a unique psychological construct that moderately overlapped with constructs of narcissism and global entitlement. The discussion focuses on the developmental and psychodynamic sources of the sense of relational entitlement. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Preparation of 2D sequences of corneal images for 3D model building

A confocal microscope provides a sequence of images, at incremental depths, of the various corneal layers and structures. From these, medical practioners can extract clinical information on the state of health of the patient's cornea. In this work we are addressing problems associated with capturing and processing these images including blurring, non-uniform illumination and noise, as well as the displacement of images laterally and in the anterior–posterior direction caused by subject movement. The latter may cause some of the captured images to be out of sequence in terms of depth. In this paper we introduce automated algorithms for classification, reordering, registration and segmentation to solve these problems. The successful implementation of these algorithms could open the door for another interesting development, which is the 3D modelling of these sequences.     

Colloidal Stability for Concentrated Zirconia Aqueous Suspensions

This work started as part of an investigation into the mechanisms by which fine zirconia aqueous dispersions can be processed for ceramic materials engineering. Aqueous dispersions of TZ3Y fine zirconia particles obtained by dispersion of dry powder in acidic solutions (pH 3) have been subjected to compression through osmotic experiments. The results show a behavior that is unusual when compared with the classical behavior of colloidal dispersions. Indeed, the 50 nm particles are well dispersed and protected from aggregation by electrical double layers, with a high zeta potential (60–80 mV). Yet, during osmotic compression, the dispersion goes from a liquid state to a gel state at a rather low volume fraction, φ=0.2, whereas the liquid–solid transition for repelling particles is expected to occur only at φ=0.5. This early transition to a state in which the dispersion does not flow may be a severe drawback in some uses of these dispersions, and thus it is important to understand its causes. A possible cause of this early aggregation is the presence of a population of very small particles, which are seen in osmotic stress experiments and in light scattering. We propose that aggregation could result from the compression of this population, through either of the following mechanisms: (a) An increase in pressure causes the small particles to aggregate with each other and with the larger ones or (b) An increase in pressure induces a depletion flocculation phenomenon, in which the large particles are pushed together by the smaller ones.     

Impact of Botanical Pesticides Derived from Melia azedarach and Azadirachta indica Plants on the Emission of Volatiles that Attract Parasitoids of the Diamondback Moth to Cabbage Plants

Herbivorous and carnivorous arthropods use chemical information from plants during foraging. Aqueous leaf extracts from the syringa tree Melia azedarach and commercial formulations from the neem tree Azadirachta indica, Neemix 4.5^®, were investigated for their impact on the flight response of two parasitoids, Cotesia plutellae and Diadromus collaris. Cotesia plutellae was attracted only to Plutella xylostella-infested cabbage plants in a wind tunnel after an oviposition experience. Female C. plutellae did not distinguish between P. xylostella-infested cabbage plants treated with neem and control P. xylostella-infested plants. However, females preferred infested cabbage plants that had been treated with syringa extract to control infested plants. Syringa extract on filter paper did not attract C. plutellae. This suggests that an interaction between the plant and the syringa extract enhances parasitoid attraction. Diadromus collaris was not attracted to cabbage plants in a wind tunnel and did not distinguish between caterpillar-damaged and undamaged cabbage plants. Headspace analysis revealed 49 compounds in both control cabbage plants and cabbage plants that had been treated with the syringa extract. Among these are alcohols, aldehydes, ketones, esters, terpenoids, sulfides, and an isothiocyanate. Cabbage plants that had been treated with the syringa extract emitted larger quantities of volatiles, and these increased quantities were not derived from the syringa extract. Therefore, the syringa extract seemed to induce the emission of cabbage volatiles. To our knowledge, this is the first example of a plant extract inducing the emission of plant volatiles in another plant. This interesting phenomenon likely explains the preference of C. plutellae parasitoids for cabbage plants that have been treated with syringa extracts.     

Case Study of Lean in Hospital Admissions to Inspire Culture Change

Abstract

The hospital admissions process is a distinct experience for patients as this is where they start their journey for medical care, usually with a mix of anxiety and anticipation about what is to follow. This process also happens to be long and stressful, with numerous steps, frequent delays, and the occasional glitches along the way. In this study, we used lean thinking and discrete-event simulation to map and model the inpatient admissions process at a multi-specialty hospital in order to improve patient flow and reduce unnecessary waiting and handling by patients and staff. We found that by applying a combination of simple but complementary lean techniques, it was possible to reduce the total patient time in the system by up to 43%, without incurring additional costs or using more resources. The potential for achieving substantial improvements at low cost, combined with the approach of validation-prior-to-implementation adopted in this study, can both help process engineers and engineering managers to build support for any proposed lean initiative. This also makes it possible to sustain continuous improvement in the long term, which is at the heart of the lean approach.     

Effectiveness of advanced composites in repairing heat-damaged RC columns

Thirteen rectangular RC column specimens, constructed at 1/3 scale, were tested under axial loading to investigate the use of advanced composites in repairing heat-induced damage. Eleven of the column specimens were subjected to elevated temperatures of 500 °C for 3 h. Nine heat-damaged columns were repaired using carbon fiber reinforced polymer (CFRP) sheets and plates. The effects of wrapping configuration, thickness of wrapping sheets, inclusion of plates as externally-bonded longitudinal reinforcement and the area of plates were examined using seven repair schemes. Test results confirmed that elevated temperatures adversely affect the axial load resistance and axial stiffness of the columns while increasing their toughness. Buckling under pure compressive loads was evident in heat-damaged columns except in those repaired using longitudinal CFRP plates. Partial wrapping with unidirectional CFRP sheets was found ineffective in augmenting the axial load capacity and stiffness of the damaged columns whereas full wrapping increased their axial load resistance and toughness. Using externally-bonded longitudinal CFRP plates, confined with circumferential wraps, significantly enhanced the initial axial stiffness and axial load resistance of the damaged columns. However, none of the seven repair schemes investigated in this study managed to regain the original axial stiffness and load resistance of the undamaged columns.