Access and Affordability of Electricity in Developing Countries

A key objective of developing countries is to provide affordable access to modern energy services in order to support economic and social development. The paper presents a number of arguments for why and in which way energy access and affordability can play a key role in national development programs and in achieving the Millennium Development Goals. Approaches for measuring accessibility and affordability are presented, drawing on case studies of Bangladesh. Brazil, and South Africa, countries with different rates of electrification. Affordability of using electricity is examined in relation to the energy expenditure burden for households and time consumption. Conclusions focus on lessons learned and recommendations for implementing policies, instruments, and regulatory measures to tackle the challenge of affordability. (C) 2011 Elsevier Ltd. All rights reserved.

Skewness, splitting number and vertex deletion of some toroidal meshes

The skewness sk(G) of a graph G = (V, E) is the smallest integer sk(G) >= 0 such that a planar graph can be obtained from G by the removal of sk(C) edges. The splitting number sp(G) of C is the smallest integer sp(G) >= 0 such that a planar graph can be obtained from G by sp(G) vertex splitting operations. The vertex deletion vd(G) of G is the smallest integer vd(G) >= 0 such that a planar graph can be obtained from G by the removal of vd(G) vertices. Regular toroidal meshes are popular topologies for the connection networks of SIMD parallel machines. The best known of these meshes is the rectangular toroidal mesh C(m) x C(n) for which is known the skewness, the splitting number and the vertex deletion. In this work we consider two related families: a triangulation Tc(m) x c(n) of C(m) x C(n) in the torus, and an hexagonal mesh Hc(m) x c(n), the dual of Tc(m) x c(n) in the torus. It is established that sp(Tc(m) x c(n)) = vd(Tc(m) x c(n) = sk(Hc(m) x c(n)) = sp(Hc(m) x c(n)) = vd(Hc(m) x c(n)) = min{m, n} and that sk(Tc(m) x c(n)) = 2 min {m, n}.

Cognitive impairment in cancer pain patients receiving opioids

This study aimed to compare cognitive function of cancer pain patients being given opioids during their cancer treatment (n = 14) with that of patients receiving treatment without opioids (n = 12). Correlations between cognitive function, pain intensity, and opioid dose were analyzed. Patients were assessed 3 times in a I-month period, using the Trail-Making Test, Mini-Mental State Examination, Digit Span, and Brief Cognitive Screening Battery. Opioid use was not associated with clear cognitive impairment. Patients being treated without opioids did perform better in the Digit Span Test reverse-order test (P = .029) and the clock drawing test (P = .023), but the differences arose in just I assessment in each case. Pain intensity correlated negatively with scores in the Mini-Mental State Examination (P = .001) and some Brief Cognitive Screening Battery tests (incidental recall, immediate recall, and late recall; P <= .042) in the group receiving opioids. Opioid dose did not correlate with any of the measures of cognitive performance. However, the patients with the worst performance scores were those with more severe pain. Further studies are needed to clearly distinguish between the effects of opioids versus the effects of pain.

Categories of manual asymmetry and their variation with advancing age

Manual asymmetries were analyzed in 18- to 63-year-old right-handers in different motor tasks. This analysis aimed at describing the asymmetry profile for each task and assessing their stability across ages. For this purpose, performance of the right and left hands were analyzed in the following aspects: simple reaction time, rate of sequential finger movements, maximum grip force, accuracy in anticipatory timing, rate of repetitive tapping, and rate of drawing movements. In addition, stability of manual preference across ages was assessed through the Edinburgh inventory (Oldfield, 1971). The results indicated different profiles of manual asymmetry, with identification of three categories across tasks: symmetric performance (asymmetry indices close to zero), inconsistent asymmetry (asymmetry indices variable in magnitude and direction), and consistent asymmetry (asymmetry indices favoring a single hand). The different profiles observed in the young adults were stable across ages with two exceptions: decreased lateral asymmetry for maximum grip force and increased asymmetry for sequential drawing in older individuals. These results indicate that manual asymmetries are task specific. Such task specificity is interpreted to be the result of different sensorimotor requirements imposed by each motor task in association with motor experiences accumulated over the lifetime. Analysis of manual preference showed that strength of preference for the right hand was greater in older individuals. (C) 2008 Elsevier Masson Srl. All rights reserved.

Correlation of Modified Natural Rubber Properties by Artificial Neural Networks

Natural rubber (NR) is a raw material largely used by the modern industry; however, it is common that chemical modifications must be made to NR in order to improve properties such as hydrophobicity or mechanical resistance. This work deals with the correlation of properties of NR modified with dimethylaminoethylmethacrylate or methylmethacrylate as grafting agents. Dynamic-mechanical behavior and stress/strain relations are very important properties because they furnish essential characteristics of the material such as glass transition temperature and rupture point. These properties are concerned with different physical principles; for this reason, normally they are not related to each other. This work showed that they can be correlated by artificial neural networks (ANN). So, from one type of assay, the properties that as a rule only could be obtained from the other can be extracted by ANN correlation. POLYM. ENG. SCI., 49:499-505, 2009. (c) 2009 Society of Plastics Engineers

Evaluation of austenitic-ferritic stainless steel wires for orthodontic applications

Several studies have shown that austenitic stainless steels are suitable for use in the final phases of orthodontic treatments, such as finishing and retention. These steels demonstrate appropriate mechanical properties, such as high ultimate tensile strength and good corrosion resistance. A new class of materials, the austenic-ferritic stainless steels, is substituting for austenitic stainless steels in several industrial applications where these properties are necessary. This work supports the hypothesis that orthodontic wires of austenic-ferritic stainless steels can replace austenitic stainless steels. The advantages are cost reduction and decrease of the nickel hypersensitivity effect in patients undergoing orthodontic treatments. The object of this study was to evaluate wires of austenitic-ferritic stainless steel SEW 410 Nr. 14517 (Cr26Ni6Mo3Cu3) produced by cold working through rolling and drawing processes. Tests were performed to evaluate the ultimate tensile strength, hardness, ductility, and formability. In accordance with technical standards the wires exhibited ultimate tensile strength and ductility suitable for orthodontic clinical applications. These austenitie-ferritic wires can be an alternative to substitute the common commercial wires of austenic stainless steels with the advantage of decreasing the nickel content.

Cracking formation on the surface of extruded photodegraded polypropylene plates

The cracking formation during the photodegradation of polypropylene (PP) plates (1 mm thickness), with (PPOx) and without pro-oxidant [PP), has been investigated. The plates were produced by extrusion in an industrial production line and were exposed to ultraviolet radiation in the laboratory for periods of up to 480 hr. The samples were investigated by infrared spectroscopy- FTIR, optical light microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results showed that the extension of photodegradation process is more intense for PPOx than for PP samples. For both samples, cracks were formed at the surface perpendicularly to the flow-lines. However the cracks frequency was different for both samples and sides of sample. The crack frequency was correlated with chain orientation, A(110); it was shown that lower degrees of orientation resulted in lower crack frequency. POLYM. ENG. SCI., 48:365-372, 2008. (c) 2007 Society of Plastics Engineers.

Quantification of Clay Dispersion in Nanocomposites of Styrenic Polymers

Polymer-clay nanocomposites are materials with many interesting structures, properties, and potential applications. Microstructural evaluation of a nanocomposite is not an easy task, as clay may form hierarchical structures which may look different when observed at various magnifications under a microscope, and also as the concepts of ""intercalation"" and ""exfoliation"" are not self-sufficient to describe its morphology. In this work polymer-clay nanocomposites of polystyrene and two styrene-containing block copolymers (styrene-butadiene-styrene and styrene-ethylene/butylene-styrene) were prepared using three different techniques. Clay dispersion was evaluated by a recently developed microscopy image analysis procedure, combining the analysis of optical and transmission electron micrographs, and the characterization was complemented by X-ray diffraction and rheological measurements. The results showed better clay dispersion for both block copolymers nanocomposites, mainly due to their molecular architectures. Moreover, the techniques which showed the best results involved mixing the materials in a solvent medium. POLYM. ENG. SCI., 50:257-267, 2010. (C) 2009 Society of Plastics Engineers

Effect of UV Radiation and Pro-Oxidant on PP Biodegradability

The effect of ultraviolet exposure on the biodegration of poly(propylene) without (PP) and with 0.3 (wt/wt) (PPOx) pro-oxidant additives, produced by extrusion was studied. After UV exposure the samples were submitted to biodegradation (weight loss) in prepared soils. The samples before and after UV exposure were analyzed using differential scanning calorimetry, Fourier transform infrared spectroscopy, size exclusion chromatography, and optical microscopy. The exposure to UV radiation lead to more intense degradation of PPOx than of PP; the amount of carbonyl groups was larger for the PPOx samples than for PP, as well as the decrease in the T(m) and in the molecular weight. The samples exposed to UV radiation showed some level of fragmentation after 56 days when placed in the prepared soil; the samples which were exposed to UV for 480 h presented just a small weight loss. POLYM. ENG. SCI., 49:123-128, 2009. (C) 2008 Society of Plastics Engineers

Preparation and characterization of crosslinked resins containing ferrite particles

Micrometer-sized magnetic particles hosted on network material were successfully prepared by a simple chemical process (ion exchange followed by co-precipitation) from commercial styrene-divinylbenzene copolymers. Energy dispersive X-ray spectroscopy (EDS) coupled to scanning electron microscopy (SEM) allowed the observation of submicron particles. All the produced spherical beads have presented metallic particles (NiFe2O4, CuFe2O4, CoFe2O4, or MnFe2O4), either as isolated particles or agglomerates, located on their external and internal (within pores) The thermal stability of the composites, evaluated by thermogravimetric techniques, were found to be dependent on the amount of ferrite particles incorporated into them.

Biodegradable nanosize particles of poly(L,L-lactide)-b-poly(ethylene glycol)-b-poly(L,L-lactide)

Two series of poly(L,L-lactide-b-ethylene glycol-b-L,L-lactide) copolymers, PLA-PEO-PLA, were synthesized by polymerization Of L,L-lactide using a dihydroxy-terminated poly(ethylene glycol) (PEG) (M-n = 4000 or 600 g/mol) as coinitiator and stannous 2-ethylhexanoate, Sn(Oct)(2), as initiator. The synthesized copolymers have shown high stereoregularity as observed by C-13 NMR analyses. The nanoparticles were prepared by using a solvent diffusion method and the self-assemblage process and were characterized by NMR and SEM. It was possible to conclude that the self-assembled particles presented a core-shell structure characterized by a hydrophobic PLA core and a hydrophilic PEG shell, thus the NMR of the aqueous solutions indicated a quasi-solid behavior for the particles` interior. The diameters of the spherical particles as observed by SEM were in the 50-250 nm range, depending on the copolymer composition and the preparation procedure.

Photooxidative behavior of polystyrene-montmorillonite nanocomposites

The weathering behavior of polystyrene and polystyrene-montmorillonite composites containing 2.5, 5.0, and 7.5 wt% of montmorillonite (MMT) was investigated. Samples were exposed to UV radiation for periods of up to similar to 12 weeks and their molecular weight, chemical changes, and mechanical properties were monitored as a function of time. The addition of MMT was shown to improve the photostability of all composites investigated, probably because of a screen effect against UV radiation and barrier effect against diffusion of oxygen promoted by the silicate layers of MMT. Scanning electron microscopy of fracture surfaces of degraded samples showed that there is a degraded layer near the surface that provided a recovery of tensile strength of the samples.

Knowledge and information flows in supply chains: A study on pharmaceutical companies

A great deal of attention in the supply chain management literature is devoted to study material and demand information flows and their coordination. But in many situations, supply chains may convey information from different nature, they may be an important channel companies have to deliver knowledge, or specifically, technical information to the market. This paper studies the technical flow and highlights its particular requirements. Drawing upon a qualitative field research, it studies pharmaceutical companies, since those companies face a very specific challenge: consumers do not have discretion over their choices, ethical drugs must be prescribed by physicians to be bought and used by final consumers. Technical information flow is rich, and must be redundant and early delivered at multiple points. Thus, apart from the regular material channel where products and order information flow, those companies build a specialized information channel, developed to communicate to those who need it to create demand. Conclusions can be extended to supply chains where products and services are complex and decision makers must be clearly informed about technology-related information. (C) 2009 Elsevier B.V. All rights reserved.

Stress cracking and photodegradation behavior of polycarbonate. The combination of two major causes of polymer failure

This work investigates the effects of photodegradation on the environmental stress cracking resistance of polycarbonate (PC). Injection molded samples were exposed to the ultraviolet (UV) light for various times in the laboratory prior to solvent contact. The bars were then stressed with two different loads in a tensile testing machine under the presence of ethanol. During this period, the stress relaxation was monitored and, after unloading, the ultimate properties were evaluated. Complementary tests were done by size exclusion chromatography, UV-visible spectroscopy, scanning electron microscopy, and light microscopy. The results indicated that ethanol causes significant modification in PC, with extensive surface crazing as well as reduction in mechanical properties. The previous degraded samples showed a higher level of stress relaxation and a greater loss in tensile strength in comparison with the undegraded ones. The synergist action of photodegradation and stress cracking in PC may be a consequence of the chemical changes caused by oxidation.

Social behaviour of collared peccaries (Pecari tajacu) under three space allowances

Captive breeding of peccaries is on the increase in neotropical countries. Few studies, however, have reported behavioural responses of wild animals under farmed conditions. Therefore, the aim of this study was to evaluate the effects of space allowance on the occurrence of social behaviour patterns on farmed collared peccary (Pecan tajacu). We observed three herds of collared peccaries each containing eight acquainted individuals. Using a 3 x 3 Latin square design, herds were allocated, in a random order, to one of the three experimental enclosures, each with a different size. 375, 750 and 1,500 m(2) of total available area, each with three wooden shelters. We recorded all the occurrences of selected positive and agonistic behavioural patterns that occurred 90 min before and during feeding Enclosure size had a significant effect on agonistic patterns of peccaries during feeding, in that more agonistic behaviour was observed in smaller spaces We also found that shelter usage increased as space decreased Differing space allowances, however, did not have an effect on the occurrence of positive interactions that were more frequent before compared to during feeding. We concluded that enclosure size had an effect on the expression of agonistic be and the use of shelters by collared peccaries Thus, animal welfare can be improved by adopting at least 187 5 m(2) per peccary. In addition, our study also confirmed the importance of shelter areas in collared peccary husbandry.