Multivariate granger causality between electricity consumption, exports and GDP : Evidence from a panel of Middle Eastern countries

This paper examines the causal relationship between electricity consumption, exports and gross domestic product (GDP) for a panel of Middle Eastern countries. We find that for the panel as a whole there are statistically significant feedback effects between these variables. A 1 per cent increase in electricity consumption increases GDP by 0.04 per cent, a 1 per cent increase in exports increases GDP by 0.17 per cent and a 1 per cent increase in GDP generates a 0.95 per cent increase in electricity consumption. The policy implications are that for the panel as a whole these countries should invest in electricity infrastructure and step up electricity conservation policies to avoid a reduction in electricity consumption adversely affecting economic growth. Further policy implications are that for the panel as a whole promoting exports, particularly non-oil exports, is a means to promote economic growth and that expansion of exports can be realized without having adverse effects on energy conservation policies.

Performance of wrought aluminium and magnesium alloy tubes in three-point bending

This present work examines the load carrying capacity, energy absorption and fracture characteristics of wrought magnesium and aluminium alloy tubes in three-point bending. Magnesium alloy AZ31, and aluminium alloys 6063 and 7075, were extruded into cylindrical tubes of both equivalent thickness and mass. A strong thickness effect was present meaning that the AZ31 tube had significantly higher load and energy absorption performance than an equivalent mass 6063 tube, albeit not as high as the 7075 tube. Hinge formation and maximum load was delayed for the magnesium alloy, meaning that a high energy absorption rate persisted to higher deformation displacements than the aluminium alloys. It was also found that fracture during deformation was dependent on the indenter diameter, tube thickness and lower support separation.

Can dietary lipid source circadian alternation improve omega-3 deposition in rainbow trout?

With the salmonid industry currently exploiting the vast majority of globally available fish oil, there is the need to optimise fish oil utilisation by increasing its efficiency in terms of transferring the health-promoting long chain omega-3 fatty acids (n−3 LC-PUFA) into farmed fish flesh. The aim of this study was to evaluate if dietary fatty acid deposition is affected by the time of feeding, and hence identify possible innovative feeding strategies towardsmore efficient use of dietary fish oil. Over a period of 12 weeks, three diets with different lipid sources, canola oil (CO), fish oil (FO) or a 50/50 blend of the two oils (Mix), were alternated daily and fed to rainbow trout (Oncorhynchus mykiss). Six treatments were administered to fish, reference treatment (REF, continuously fed FO), control treatment (CT, continuously fed Mix), am canola oil ration (amCOR), pm canola oil ration (pmCOR), am canola oil satiation (amCOS) and pm canola oil satiation (pmCOS). Fish received either the CO diet in the am or pm feeds and received the FO diet at the opposite time. A significant increase in growth and feed consumption was noted in the pmCOS treatment. Fillet fatty acid profile was modified by associated feeding schedules and was generally reflective of dietary fatty acid profile. No significant increases in n−3 LCPUFA deposition were observed. However, both linoleic acid (18:2n−6) and α-linolenic acid (18:3n−3) contents were significantly higher in pmCOR compared to amCOR and CT. The results of the present study suggest the existence of cyclical circadian patterns in fatty acid deposition in rainbow trout.

Synthesis and physical property characterisation of phosphonium ionic liquids based on P(O)2(OR)2− and P(O)2(R)2− anions with potential application for corrosion mitigation of magnesium alloys

Phosphonium cation based ionic liquids (ILs) have become of interest due to their unique chemical and electrochemical stability as well as their promising tribological properties. At the same time, interest has also grown in the use of phosphate and phosphinate based ionic liquids for corrosion protection of reactive metals. In this work we describe the synthesis and characterization of six novel ionic liquids based on the tetraalkylphosponium cation coupled with organophosphate and organophosphinate anions and their sulfur analogues. The conductivity and viscosity of these ILs has been measured and discussed in terms of the nature of the interactions, effect of anion basicity and the extent of ionic character. The reaction of the IL with a ZE41 magnesium aerospace alloy surface is also demonstrated.

Are safety-related features of the road environment associated with smaller declines in physical activity among youth?

This study examined how objective measures of the local road environment related to safety were associated with change in physical activity (including active transport) among youth. Few longitudinal studies have examined the impact of the road environment on physical activity among children/adolescents in their neighborhoods. Participants were children aged 8–9 years (n=170) and adolescents aged 13–15 years (n=276) in 2004. Data were collected in 2004 and 2006 during followup of participants recruited initially in 2001 from 19 primary schools in Melbourne, Australia. Walking/cycling to local destinations was parent-reported for children and self-reported by adolescents. Moderate-to-vigorous physical activity (MVPA) during nonschool hours was recorded using accelerometers. Road environment features in each participant’s neighborhood (area within 800 m radius of their home) were measured objectively using a Geographical Information System. Linear regression analyses examined associations between road features and changes in active transport (AT) and MVPA over 2 years. Children’s AT increased but MVPA levels decreased in both age groups; on average, younger girls recorded the greatest declines. The number of traffic/pedestrian lights was associated with ΔAT among younger girls (B=0.45, p=0.004). The total length of walking tracks (in meters) was associated with ΔAT among younger girls (B=0.0016, p=0.015) and adolescent girls (B=0.0016, p=0.002). For adolescent boys, intersection density was associated with ΔAT (B=0.03, p=0.030). Slow points were associated with ΔMVPA among younger boys before school (B=1.55, p=0.021), while speed humps were associated with ΔMVPA among adolescent boys after school (B=0.23, p=0.015). There were many associations for adolescent girls: for example, the total length of local roads (B=0.49, p=0.005), intersection density (B=0.05, p=0.036), and number of speed humps (B=0.33, p=0.020) were associated with ΔMVPA during nonschool hours. Safety-related aspects of the built environment are conducive to physical activity among youth and may help stem age-related declines in physical activity. Passive road safety interventions may promote AT and physical activity among less active girls, in particular.

Ingrowth of human mesenchymal stem cells into porous silk particle reinforced silk composite scaffolds : an in vitro study

Silk fibroin protein is biodegradable and biocompatible, exhibiting excellent mechanical properties for various biomedical applications. However, porous three-dimensional (3-D) silk fibroin scaffolds, or silk sponges, usually fall short in matching the initial mechanical requirements for bone tissue engineering. In the present study, silk sponge matrices were reinforced with silk microparticles to generate protein-protein composite scaffolds with desirable mechanical properties for in vitro osteogenic tissue formation. It was found that increasing the silk microparticle loading led to a substantial increase in the scaffold compressive modulus from 0.3 MPa (non-reinforced) to 1.9 MPa for 1:2 (matrix:particle) reinforcement loading by dry mass. Biochemical, gene expression, and histological assays were employed to study the possible effects of increasing composite scaffold stiffness, due to microparticle reinforcement, on in vitro osteogenic differentiation of human mesenchymal stem cells (hMSCs). Increasing silk microparticle loading increased the osteogenic capability of hMSCs in the presence of bone morphogenic protein-2 (BMP-2) and other osteogenic factors in static culture for up to 6 weeks. The calcium adsorption increased dramatically with increasing loading, as observed from biochemical assays, histological staining, and microcomputer tomography (μCT) analysis. Specifically, calcium content in the scaffolds increased by 0.57, 0.71, and 1.27 mg (per μg of DNA) from 3 to 6 weeks for matrix to particle dry mass loading ratios of 1:0, 1:1, and 1:2, respectively. In addition, μCT imaging revealed that at 6 weeks, bone volume fraction increased from 0.78% for non-reinforced to 7.1% and 6.7% for 1:1 and 1:2 loading, respectively. Our results support the hypothesis that scaffold stiffness may strongly influence the 3-D in vitro differentiation capabilities of hMSCs, providing a means to improve osteogenic outcomes.

Sliding distance, contact pressure and wear in sheet metal stamping

This paper directly examines the contact sliding distance experienced during a typical sheet metal stamping process-an area that has largely been neglected in the literature. A method to numerically quantify the sliding distance is proposed. The sliding distance predicted from this method, and the contact pressure obtained from numerical simulation, allow the recently identified time-dependent contact conditions on the die and blank surfaces to be completely characterized. Consequently, a new insight into the wear/galling that occurs at the die radius in sheet metal stamping is gained. The results show that the region close to zero degrees on the die radius is likely to experience the most wear, with the identified transient stage contributing to a large proportion of the total wear. Additionally, the region on the blank surface often observed to be heavily burnished - the die impact line - is estimated to experience the highest wear severity due to the transient contact conditions. The proposed method to numerically quantify the sliding contact conditions can be applied as a general approach to study any other two-body sliding contact situations.

Effects of additives on the cloud points of selected nonionic linear ethoxylated alcohol surfactants

Effects of various additives including inorganic salts, nonionic and ionic surfactants, water-soluble polymers and alcohols on the cloud points of three linear nonionic surfactants, Tergitol 15-S-7, Tergitol 15-S-9 and Neodol 25-7, were investigated. These surfactants are readily biodegradable and either linear primary or secondary ethoxylated alcohols. Cloud points of these surfactants were functions of their concentrations and concentrations of additives. The cloud points of nonionic surfactant mixtures lay in between the cloud points of individual component surfactants. Presence of two ionic surfactants, sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB), increased the cloud point of 1 wt% Tergitol 15-S-7 micellar solution dramatically when concentrations of ionic surfactants approaching their critical micelle concentration. Addition of water-soluble polymers decreased the cloud point, while addition of inorganic salts can either increase or decrease the cloud points. However, the effect of an alcohol additive on cloud point was dependent on its chain length or its water solubility. Interestingly, synergistic effects between sulfate or phosphate and pentanol on depression of cloud points of Tergitol 15-S-9 were discovered. A linear model predicting cloud points of Tergitol 15-S-X (X = 7, 9 and 12) surfactants and Neodol 25-X (X = 7, 9 and 12) surfactants were proposed with a correlation to logarithm of their ethylene oxide numbers.

Optical phase change at the interface between mica and thin silver film

We describe a simple experiment which allows unequivocal determination of optical phase change upon reflection of light at the mica-silver interface. While the physical origin of such a phase change at the dielectric-metal interface is well understood to lie in absorption of electromagnetic energy by the metal, inconsistency and ambiguity has persisted as to what its sign and magnitude should be in the field of thin film optics. Most commonly, it has been assigned to be negative for mathematical convenience or just arbitrarily. Our finding shows that with the convention exp(-iωt) for time dependence of the electromagnetic wave, the phase change at the interface between mica and the thin silver film is necessarily positive and its magnitude falls between π and 3π/2 for silver thicknesses down to nanometres. This gives a physically reasonable correspondence to an increased equivalent thickness of the dielectric material, and it clarifies the assignment of interference orders in the harmonic series in a spectrum.

Behavioural and physical characteristics associated with vitamin D status in women

For most people in Australia, the primary source of vitamin D is casual exposure to sunlight. Hypovitaminosis D has been reported for high-risk populations, but little has been documented for women of all ages living in the community. Using cross-sectional data, we aimed to describe physical and behavioural characteristics associated with serum 25-hydroxyvitamin D (25OHD) for such women and to determine the association of serum 25OHD with hypertension and bone health. Serum 25OHD, parathyroid hormone (PTH), blood pressure, bone mineral density (BMD) and anthropometry were measured in a random sample of 861 women aged 20–92 years enrolled in the Geelong Osteoporosis Study, set in a temperate region at latitude 38–39°S. Lifestyle factors (including diet, smoking, medication use, socio-economic status, residence, education, occupation, and physical activity) were documented by questionnaire. In season-adjusted models for women aged 20–54 years, physical activity and living with a partner were independently and positively associated with serum 25OHD; associations with weight and waist–hip ratio were negative. Among older women, physical activity, vitamin D intake and urban dwelling were positively associated with serum 25OHD; age, weight and smoking were negative. Compared with the lowest tertile, those in the highest serum 25OHD tertile were less likely to have elevated serum PTH (adjusted OR = 0.25, 95% CI 0.16–0.41) and high blood pressure (adjusted OR = 0.40, 95% CI 0.22–0.72), and more likely to have normal hip and spine BMD (adjusted OR = 1.65, 95% CI 1.08–2.52). In multivariable models adjusting for season, age, weight (and height), BMD was associated with serum 25OHD at the spine, hip and whole body; no associations were detected at the forearm and no other characteristics were identified as confounders. Factors associated with high vitamin D status generally reflected healthy body habitus and active lifestyles. In contrast, excessive weight and smoking were associated with poorer vitamin D status. Women with high vitamin D were less likely to have elevated PTH, hypertension or bone deficits than women with poor levels.

Association between food marketing exposure and adolescents' food choices and eating behaviors

The present study examined associations between food marketing exposure and adolescents’ food choices and reported consumption of energy-dense and nutrient-poor (EDNP) foods. A cross-sectional survey of 12,188 Australian secondary students aged 12–17 years was conducted, using a web-based self-report questionnaire. Measures included students’ level of exposure to commercial television and non-broadcast types of food marketing, whether they had tried a new product or requested a product they had seen advertised, and their reported consumption of fast food, sugary drinks and sweet and salty snacks. Results indicated greater exposure to commercial television, print/transport/school food marketing and digital food marketing were all independently associated with students’ food choices. High commercial television viewers (>2 h/day) were more likely to report higher consumption of EDNP foods (ORs ranged from 1.31 for fast food to 1.91 for sweet snacks). Some associations between digital food marketing exposure and students’ eating behaviors were found; however, print/transport/school food marketing was only related to sweet snack consumption. These study results suggest that cumulative exposure to television food advertising and other food marketing sources are positively linked to adolescents’ food choices and eating behaviors. Policy changes to restrict food marketing to young people should include both television and non-broadcast media.