The effect of light intensity and temperature on photocatalytic water splitting

Photocatalytic water splitting is a process which could potentially lead to commercially viable solar hydrogen production. This thesis uses an engineering perspective to investigate the technology. The effect of light intensity and temperature on photocatalytic water splitting was examined to evaluate the prospect of using solar concentration to increase the feasibility of the process. P25 TiO2 films deposited on conducting glass were used as photocatalyst electrodes and coupled with platinum electrodes which were also deposited on conducting glass. These films were used to form a photocatalysis cell and illuminated with a Xenon arc lamp to simulate solar light at intensities up to 50 suns. They were also tested at temperatures between 20°C and 100°C. The reaction demonstrated a sub-linear relationship with intensity. Photocurrent was proportional to intensity with an exponential value of 0.627. Increasing temperature resulted in an exponential relationship. This proved to follow an Arrhenius relationship with an activation energy of 10.3 kJ mol-1 and a pre-exponential factor of approximately 8.7×103. These results then formed the basis of a mathematical model which extrapolated beyond the range of the experimental tests. This model shows that the loss of efficiency from performing the reaction under high light intensity is offset by the increased reaction rate and efficiency from the associated temperature increase. This is an important finding for photocatalytic water splitting. It will direct future research in system design and materials research and may provide an avenue for the commercialisation of this technology.

Determining the optimal proportion of design in design-build request for proposals (RFPs)

The design-build (DB) system is a popular and effective delivery method of construction projects worldwide. After owners decide to procure their projects through the DB system, they may wish to determine the optimal proportion of design to be provided in the DB request for proposals (RFPs), which serve as solicitations for design-builders and describe the scope of work. However, this presents difficulties to DB owners and there is little, if any, systematic research in this area. This paper reports on an empirical study in the USA entailing both an online questionnaire survey and Delphi survey to identify and evaluate the factors influencing owners’ decisions in determining the proportion of design to include in DB RFPs. Eleven factors are identified, i.e. (1) clarity of project scope; (2) applicability of performance specifications; (3) desire for design innovation; (4) site constraints; (5) availability of competent design-builders; (6) project control requirements; (7) user group involvement level; (8) third party requirements; (9) owner experience with DB; (10) project complexity; and (11) schedule constraints. A statistically significant agreement on the eleven factors was also obtained from the (mainly non-owner) Delphi experts. Although some of the experts hold different opinions on how these factors affect the proportion of design, these findings furnish various stakeholders with a better understanding of the delivery process of DB projects and the appropriate provision of project information in DB RFPs. As the result is mainly industry opinion concerning the optimal proportion of design, in addition and for completeness, future studies should be conducted to obtain a big picture of the optimal proportion of design by means of seeking owners’ inputs.

Victimization experiences of adolescents in Malaysia

Purpose There has been little community-based research regarding multiple-type victimization experiences of young people in Asia, and none in Malaysia. This study aimed to estimate prevalence, explore gender differences, as well as describe typical perpetrators and family and social risk factors among Malaysian adolescents. Methods A cross-sectional survey of 1,870 students was conducted in 20 randomly selected secondary schools in Selangor state (mean age: 16 years; 58.8% female). The questionnaire included items on individual, family, and social background and different types of victimization experiences in childhood. Results Emotional and physical types of victimization were most common. A significant proportion of adolescents (22.1%) were exposed to more than one type, with 3% reporting all four types. Compared with females, males reported more physical, emotional, and sexual victimization. The excess of sexual victimization among boys was due to higher exposure to noncontact events, whereas prevalence of forced intercourse was equal for both genders (3.0%). Although adult male perpetrators predominate, female adults and peers of both genders also contribute substantially. Low quality of parent–child relationships and poor school and neighborhood environments had the strongest associations with victimization. Family structure (parental divorce, presence of step-parent or single parent, or household size), parental drug use, and rural/urban location were not influential in this sample. Conclusion This study extends the analysis of multiple-type victimization to a Malaysian population. Although some personal, familial, and social factors correlate with those found in western nations, there are cross-cultural differences, especially with regard to the nature of sexual violence based on gender and the influence of family structure.

Conditional corruption

In this paper we discuss whether corruption is contagious and whether conditional cooperation matters. We use the notion of “conditional corruption” for these effects. We analyze whether the justifiability to be corrupt is influenced by the perceived activities of others. Moreover, we also explore whether – and to what extent – group dynamics or socialization and past experiences affect corruption. We present evidence using two data sets at the micro level and a large macro level international panel data set. The results indicate that the willingness to engage in corruption is influenced by the perceived activities of peers and other individuals. Moreover, the panel data set at the macro level indicates that the past level of corruption has a strong impact on the current corruption level.

Barriers and facilitators to diabetes self-management: Perspectives of older community dwellers and health professionals in China

Little is known about self-management among people with Type 2 diabetes living in mainland China. Understanding the experiences of this target population is needed to provide socioculturally relevant education to effectively promote self-management. The aim of this study was to explore perceived barriers and facilitators to diabetes self-management from both older community dwellers and health professionals in China. Four focus groups, two for older people with diabetes and two for health professionals, were conducted. All participants were purposively sampled from two communities in Shanghai, China. Six barriers were identified: overdependence on but dislike of western medicine, family role expectations, cuisine culture, lack of trustworthy information sources, deficits in communication between clients and health professionals, and restriction of reimbursement regulations. Facilitators included family and peer support, good relationships with health professionals, simple and practical instruction and a favourable community environment. The findings provide valuable information for diabetes self-management intervention development in China, and have implications for programmes tailored to populations in similar sociocultural circumstance.

Going public : do risk and choice explain differences in caesarean birth rates between public and private places of birth in Australia?

Background: Women who birth in private facilities in Australia are more likely to have a caesarean birth than women who birth in public facilities and these differences remain after accounting for sector differences in the demographic and health risk profiles of women. However, the extent to which women’s preferences and/or freedom to choose their mode of birth further account for differences in the likelihood of caesarean birth between the sectors remains untested. Method: Women who birthed in Queensland, Australia during a two-week period in 2009 were mailed a self-report survey approximately three months after birth. Seven hundred and fifty-seven women provided cross-sectional retrospective data on where they birthed (public or private facility), mode of birth (vaginal or caesarean) and risk factors, along with their preferences and freedom to choose their mode of birth. A hierarchical logistic regression was conducted to determine the extent to which maternal risk and freedom to choose one’s mode of birth explain sector differences in the likelihood of having a caesarean birth. Findings: While there was no sector difference in women’s preference for mode of birth, women who birthed in private facilities had higher odds of feeling able to choose either a vaginal or caesarean birth, and feeling able to choose only a caesarean birth. Women had higher odds of having caesarean birth if they birthed in private facilities, even after accounting for significant risk factors such as age, body mass index, previous caesarean and use of assisted reproductive technology. However, there was no association between place of birth and odds of having a caesarean birth after also accounting for freedom to choose one’s mode of birth. Conclusions: These findings call into question suggestions that the higher caesarean birth rate in the private sector in Australia is attributable to increased levels of obstetric risk among women birthing in the private sector or maternal preferences alone. Instead, the determinants of sector differences in the likelihood of caesarean births are complex and are linked to differences in the perceived choices for mode of birth between women birthing in the private and public systems.

Factors affecting technical efficiency of rice farmers in village reservoir irrigation systems of Sri Lanka

Given the importance of water for rice production, this study examines the factors affecting the technical efficiency (TE) of irrigated rice farmers in village irrigation systems (VIS) in Sri Lanka. Primary data were collected from 460 rice farmers in the Kurunagala District, Sri Lanka, to estimate a stochastic translog production frontier for rice production. The mean TE of rice farming in village irrigation was found to be 0.72, although 63% of rice farmers exceeded this average. The most influential factors of TE are membership of Farmer Organisations (FOs) and the participatory rate in collective actions organised by FOs. The results suggest that enhancement of co-operative arrangements of farmers by strengthening the membership of FOs is considered important for increasing TE in rice farming in VIS.

Weight stigma in maternity care : women's experiences and care providers' attitudes

Background: Weight stigma is pervasive in Western society and in healthcare settings, and has a negative impact on victims’ psychological and physical health. In the context of an increasing focus on the management of overweight and obese women during and after pregnancy in research and clinical practice, the current studies aimed to examine the presence of weight stigma in maternity care. Addressing previous limitations in the weight stigma literature, this paper quantitatively explores the presence of weight stigma from both patient and care provider perspectives. Methods: Study One investigated associations between pre-pregnancy body mass index (BMI) and experiences of maternity care from a state-wide, self-reported survey of 627 Australian women who gave birth in 2009. Study Two involved administration of an online survey to 248 Australian pre-service medical and maternity care providers, to investigate their perceptions of, and attitudes towards, providing care for pregnant patients of differing body sizes. Both studies used linear regression analyses. Results: Women with a higher BMI were more likely to report negative experiences of care during pregnancy and after birth, compared to lower weight women. Pre-service maternity care providers perceived overweight and obese women as having poorer self-management behaviours, and reported less positive attitudes towards caring for overweight or obese pregnant women, than normal weight pregnant women. Even care providers who reported few weight-stigmatising attitudes responded less positively to overweight and obese pregnant women. Conclusions: Overall, these results provide preliminary evidence that weight stigma is present in maternity care settings in Australia. They suggest a need for further research into the nature and consequences of weight stigma in maternity care, and for the inclusion of strategies to recognise and combat weight stigma in maternity care professionals’ training.

Assessment of the molecular structure of the borate mineral sakhaite Ca12Mg4(BO3)7(CO3)4Cl(OH)2·H2O using vibrational spectroscopy

The structure of the borate mineral sakhaite Ca12Mg4(BO3)7(CO3)4Cl(OH)2·H2O, a borate–carbonate of calcium and magnesium has been assessed using vibrational spectroscopy. Assignment of bands is undertaken by comparison with the data from other published results. Intense Raman band at 1134 cm−1 with a shoulder at 1123 cm−1 is assigned to the symmetric stretching mode. The Raman spectrum displays bands at 1479, 1524 and 1560 cm−1 which are assigned to the antisymmetric stretching vibrations. The observation of multiple carbonate stretching bands supports the concept that the carbonate units are non-equivalent. The Raman band at 968 cm−1 with a shoulder at 950 cm−1 is assigned to the symmetric stretching mode of trigonal boron. Raman bands at 627 and 651 cm−1 are assigned to the out-of-plane bending modes of trigonal and tetrahedral boron. Raman spectroscopy coupled with infrared spectroscopy enables the molecular structure of the mineral sakhaite to be assessed.

A Systematic review of a statistical vacuum circuit breaker model for condition monitoring

Vacuum circuit breaker (VCB) overvoltage failure and its catastrophic failures during shunt reactor switching have been analyzed through computer simulations for multiple reignitions with a statistical VCB model found in the literature. However, a systematic review (SR) that is related to the multiple reignitions with a statistical VCB model does not yet exist. Therefore, this paper aims to analyze and explore the multiple reignitions with a statistical VCB model. It examines the salient points, research gaps and limitations of the multiple reignition phenomenon to assist with future investigations following the SR search. Based on the SR results, seven issues and two approaches to enhance the current statistical VCB model are identified. These results will be useful as an input to improve the computer modeling accuracy as well as the development of a reignition switch model with point-on-wave controlled switching for condition monitoring

Modelling the failure of thin layered mortar joints in masonry

This paper deals with the failure of high adhesive, low compressive strength, thin layered polymer mortar joints in masonry through a contact modelling in finite element framework. Failure due to combined shear, tensile and compressive stresses are considered through a constitutive damaging contact model that incorporates traction–separation as a function of displacement discontinuity. The modelling method is verified using single and multiple contact analyses of thin mortar layered masonry specimens under shear, tensile and compressive stresses and their combinations. Using this verified method, the failure of thin mortar layered masonry under a range of shear to tension ratios and shear to compression ratios has been examined. Finally, this model is applied to thin bed masonry wallettes for their behaviour under biaxial tension–tension and compression–tension loadings perpendicular and parallel to the bed joints.

Infrared and Raman spectroscopic characterization of the carbonate mineral huanghoite - and in comparison with selected rare earth carbonates

Raman spectroscopy complimented with infrared spectroscopy has been used to study the rare earth based mineral huanghoite with possible formula given as BaCe(CO3)2F and compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of huanghoite displays three bands are at 1072, 1084 and 1091 cm−1 attributed to the symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of symmetric stretching vibration varies with mineral composition. Infrared spectroscopy of huanghoite show bands at 1319, 1382, 1422 and 1470 cm−1. No Raman bands of huanghoite were observed in these positions. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm−1 assigned to the ν3 (CO3)2− antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands for huanghoite are observed at 687, 704, 718 and 730 cm−1and assigned to the (CO3)2− ν2 bending modes. Raman bands are observed for huanghoite at around 627 cm−1 and are assigned to the (CO3)2− ν4 bending modes. Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm−1 for bastnasite, 736 and 684 cm−1 for parisite, 714 cm−1 for northupite. Raman bands for huanghoite observed at 3259, 3484 and 3589 cm−1 are attributed to water stretching bands. Multiple bands are observed in the OH stretching region for bastnasite and parisite indicating the presence of water and OH units in their mineral structure. Vibrational spectroscopy enables new information on the structure of huanghoite to be assessed.

A linkage and cross-sectional study of hypertension and obesity using a poly(A) Alu-repeat polymorphism at the glucagon receptor gene locus (17q25)

1. Previous glucagon receptor gene (GCGR) studies have shown a Gly40Ser mutation to be more prevalent in essential hypertension and to affect glucagon binding affinity to its receptor. An Alu-repeat poly(A) polymorphism colocalized to GCGR was used in the present study to test for association and linkage in hypertension as well as association in obesity development. 2. Using a cross-sectional approach, 85 hypertensives and 95 normotensives were genotyped using polymerase chain reaction primers flanking the Alu-repeat. Both hypertensive and normotensive populations were subdivided into lean and obese categories based on body mass index (BMI) to determine involvement of this variant in obesity. For the linkage study, 89 Australian Caucasian hypertension affected sibships (174 sibpairs) were genotyped and the results were analysed using GENE-HUNTER, Mapmaker Sibs, ERPA and SPLINK (all freely available from http://linlkage.rockefeller. edu/soft/list.html). 3. Cross-sectional results for both hypertension and obesity were analysed using Chi-squared and Monte Carlo analyses. Results did not show an association of this variant with either hypertension (χ2 = 6.9, P = 0.14; Monte Carlo χ2 = 7.0, P = 0.11; n = 5000) or obesity (χ2 = 3.3, P = 0.35; Monte Carlo χ2 = 3.26, P = 0.34; n = 5000). In addition, results from the linkage study using hypertensive sib-pairs did not indicate linkage of the poly(A) repent with hypertension. Hence, results did not indicate a role far the Alu-repeat in either hypertension or obesity. However, as the heterozygosity of this poly(A) repeat is low (35%), a larger number of hypertensive sib-pairs may be required to draw definitive conclusions.