Solvothermal nanoYAG synthesis: Mechanism and particle growth kinetics

This paper was accepted for publication in the journal Journal of Supercritical Fluids and the definitive published version is available at http://dx.doi.org/10.1016/j.supflu.2015.09.031NanoYAG particles with spherical morphology have been synthesised using a solvothermal method; a structure sensitive reaction, where the chemical reaction and the particle growth kinetics are interdependent. It has been observed that the primary YAG particles agglomerated into ∼30 nm clusters via a self-assembled Ostwald ripening process along (2 1 1) planes, separated by a distance of ∼0.49 nm, at 270 °C and 2.0 MPa for 2 h. These nanoclusters coalesced into single nanoparticles of ∼30 nm in size and exhibited a smaller inter planar distance of ∼0.26 nm, corresponding to the (4 2 0) planes, when synthesized at 300 °C and 8.5 MPa for 2 h. in addition, the solvent 1,4-butanediol transformed into 1,4-diacetoxybutane, this will have undergone esterification by reacting with the terminal acetate groups cleaved from the precursor, yttrium acetate. The proposed mechanism based on the analytical evidence suggests that a complete dissolution of precursors facilitated the structural re-arrangement of atoms within the planes and lead to a significantly higher degree of crystallinity. Moreover, once the particles with (4 2 0) planes had formed, they were no longer involved in facile coalescence along their preferential planes due to their lower interfacial energy compared to the (2 1 1) planes. This led to control of the particle morphology and with little agglomeration occurring in the final nanopowder

Flash sintering of beta-alumina solid electrolytes for sodium battery applications

The rechargeable sodium batteries, sodium sulphur (NaS) batteries and molten-salt sodium nickel chloride (Na-NiCl2) are proven commercially available systems, particularly for large-scale energy storage applications and electric vehicle applications respectively. They have attractive properties such as the use of abundant low-cost raw materials, high energy and power density, high faradaic efficiency of charge/discharge, zero self-discharge rate and proven long-term durability. Conventional manufacturing of the core component, the sodium beta”-alumina solid electrolyte, requires a high sintering temperatures, ~ 1600 °C to achieve high density and good ceramic quality, which contributes significantly to battery cost, energy and time consumption in production. Flash sintering, a novel low-cost electrical field-assisted sintering technology, has been investigated for sintering beta”-alumina samples in a collaboration between Lucideon Limited and Ionotec Limited. This work will describe the preliminary results on flash sintering equipment design and prototype sodium beta”-alumina ceramics with variation of the flash-sintering process parameters, i.e. current, frequency, times (incubation, development, holding), pulse experiments, current ramp rate, the on-set furnace temperature, sample geometry (discs versus open-ended tubes), electrode materials (Ag versus Pt paints), single versus double electrode and sample homogeneity. In particular, we will report a significant step towards scale up by showing results on homogeneously-sintered, highly dense more complex geometries such as tubes and closed end tubes using refined field sintering process

Aerosol-assisted fabrication of tin-doped indium oxide ceramic thin films from nanoparticle suspensions

Sn-doped In2O3 (ITO) thin films were fabricated on float glass substrates from a nanoparticle suspension using a new and inexpensive aerosol-assisted chemical transport (AACT) process. The influence of the solvent type, loading level and film deposition time on the structural, electrical and optical properties of the deposited thin films was investigated. In addition, the effect of the post-deposition heat-treatment of ITO films on the film resistivity and transparency was investigated using microwave radiation and compared with more conventional radiant heat-treated films. The SEM images of the films prepared using a 30 min deposition time with 0.20% (wt/vol%) methanolic ITO suspension provided better surface coverage compared to the other deposition times investigated. The optimised ITO films were heat-treated after deposition by either conventional radiant or microwave assisted heating methods in order to improve the inter-particle connections and film adherence. The films heat-treated after deposition by microwave annealing exhibited an average transmittance of >85% in the visible region with a resistivity of 12 Ω cm and a carrier concentration of −3.7 × 1016 cm3, which were superior to films that were heat-treated using more conventional thermal processing (despite the shorter processing time for the microwave process). The resistivity of ITO films was further decreased to 6.0 × 10−2 Ω cm with an increased carrier concentration of −8.0 × 1018 cm3 when ethyl cellulose was added to the ITO suspension prior to the AACT deposition. The enhanced conductivity of this film is due to the improved particle–particle and particle–substrate connections as observed by SEM imaging

Psychiatric disorders in Iranian children and adolescents

Objective: The aim of the present study was to investigate the epidemiology of psychiatric disorders in children and adolescents in five provinces of Iran: Tehran, Shiraz, Isfahan, Tabriz and Mashhad. Method: In the present study, we selected 9,636 children and adolescents aged 6-18 years through multistage cluster random sampling method from Tehran, Shiraz, Isfahan, Tabriz and Mashhad. We instructed the clinical psychologists to complete the Strengths and Difficulties Questionnaire (SDQ) for the participants, and those who received a high score on SDQ, completed the Persian version of Kiddie-SADS-Present and Lifetime Version (K-SADS-PL). We used descriptive analysis and 95 confidence interval to investigate the relationship between scores of the K- SADS questionnaire and demographic factors . We used one-way ANOVA to test the significant differences among the disorders according to sex, age and province of residence. Results: Based on the results, oppositional defiant disorder (ODD) (4.45) had the highest prevalence of psychiatric disorders in the five provinces and substance abuse and alcohol abuse (0) had the lowest prevalence. In addition, attention deficit hyperactivity disorder (ADHD) had the most prevalence in boys (5.03) and ODD had the most prevalence in girls (4.05). Among the three age groups, 6 to 9 year olds had the highest rates of ADHD (5.69); 10 to 14 and 15 to 18 year olds had the highest rates of ODD (4.32 and 4.37 respectively). Among the five provinces, Tehran and Mashhad allocated the highest rates of ODD; Isfahan and Shiraz had the highest rates of ADHD; and Tabriz had the highest rates of social phobia. Conclusion: The current study revealed that the overall frequency of psychiatric disorders based on Kiddie- SADS-Present and Lifetime Version (K-SADS-PL) was higher than a similar study. Moreover, in this study, among the five provinces, Tehran and Mashhad allocated the highest rates of ODD; Isfahan and Shiraz had the highest rates of ADHD; and Tabriz had the highest rates of social phobia. Therefore, these percentage of psychiatric disorders in Iran lead us toward a greater use of consultation and mental health services

What do general practitioners know about ADHD? Attitudes and knowledge among first-contact gatekeepers: systematic narrative review

Background: Attention Deficit Hyperactivity Disorder (ADHD) is a common childhood disorder with international prevalence estimates of 5 % in childhood, yet significant evidence exists that far fewer children receive ADHD services. In many countries, ADHD is assessed and diagnosed in specialist mental health or neuro-developmental paediatric clinics, to which referral by General (Family) Practitioners (GPs) is required. In such ‘gatekeeper’ settings, where GPs act as a filter to diagnosis and treatment, GPs may either not recognise potential ADHD cases, or may be reluctant to refer. This study systematically reviews the literature regarding GPs’ views of ADHD in such settings. Methods: A search of nine major databases was conducted, with wide search parameters; 3776 records were initially retrieved. Studies were included if they were from settings where GPs are typically gatekeepers to ADHD services; if they addressed GPs’ ADHD attitudes and knowledge; if methods were clearly described; and if results for GPs were reported separately from those of other health professionals. Results: Few studies specifically addressed GP attitudes to ADHD. Only 11 papers (10 studies), spanning 2000–2010, met inclusion criteria, predominantly from the UK, Europe and Australia. As studies varied methodologically, findings are reported as a thematic narrative, under the following themes: Recognition rate; ADHD controversy (medicalisation, stigma, labelling); Causes of ADHD; GPs and ADHD diagnosis; GPs and ADHD treatment; GP ADHD training and sources of information; and Age, sex differences in knowledge and attitudes. Conclusions: Across times and settings, GPs practising in first-contact gatekeeper settings had mixed and often unhelpful attitudes regarding the validity of ADHD as a construct, the role of medication and how parenting contributed to presentation. A paucity of training was identified, alongside a reluctance of GPs to become involved in shared care practice. If access to services is to be improved for possible ADHD cases, there needs to be a focused and collaborative approach to training

Psychological problems of Iranian children and adolescents: Parent report form of Strengths and Difficulties Questionnaire

Objective: The aim of this study was to evaluate the degree of psychological problems Iranian children and adolescents have, using parent report form of the Strengths and Difficulties Questionnaire (SDQ). Methods: In a community-based study, 9636 children and adolescents aged 6-17 years were selected using the multistage cluster random sampling method from five provinces of Iran: Tehran, Isfahan, Fars, Razavi Khorasan and East Azerbaijan. The parents completed the SDQ, which consisted of five subscales including emotional problems, conduct problems, hyperactivity, peer problems and prosocial behaviors. Result: The results revealed 21.4 of emotional problems, 32.9 of conduct problems, 20 of hyperactivity, 25.6 of peer problems, 7.6 of problems in prosocial behaviors and 16.7 of total difficulties among Iranian children and adolescents. We found that emotional problems were more prevalent among girls, while conduct problems, hyperactivity, total difficulties and problems in prosocial behaviors were more prevalent among boys. High educational level of parents was a protective factor against some psychological problems. Conclusion: Considering the proportion of psychological problems in Iranian children and adolescents, we need to develop and implement special policies and programs to provide appropriate mental health services. © 2014 Shadowfax Publishing and Informa UK Limited

Psychiatric disorders in Iranian children and adolescents

Objective: The aim of the present study was to investigate the epidemiology of psychiatric disorders in children and adolescents in five provinces of Iran: Tehran, Shiraz, Isfahan, Tabriz and Mashhad. Method: In the present study, we selected 9,636 children and adolescents aged 6-18 years through multistage cluster random sampling method from Tehran, Shiraz, Isfahan, Tabriz and Mashhad. We instructed the clinical psychologists to complete the Strengths and Difficulties Questionnaire (SDQ) for the participants, and those who received a high score on SDQ, completed the Persian version of Kiddie-SADS-Present and Lifetime Version (K-SADS-PL). We used descriptive analysis and 95 confidence interval to investigate the relationship between scores of the K- SADS questionnaire and demographic factors . We used one-way ANOVA to test the significant differences among the disorders according to sex, age and province of residence. Results: Based on the results, oppositional defiant disorder (ODD) (4.45) had the highest prevalence of psychiatric disorders in the five provinces and substance abuse and alcohol abuse (0) had the lowest prevalence. In addition, attention deficit hyperactivity disorder (ADHD) had the most prevalence in boys (5.03) and ODD had the most prevalence in girls (4.05). Among the three age groups, 6 to 9 year olds had the highest rates of ADHD (5.69); 10 to 14 and 15 to 18 year olds had the highest rates of ODD (4.32 and 4.37 respectively). Among the five provinces, Tehran and Mashhad allocated the highest rates of ODD; Isfahan and Shiraz had the highest rates of ADHD; and Tabriz had the highest rates of social phobia. Conclusion: The current study revealed that the overall frequency of psychiatric disorders based on Kiddie- SADS-Present and Lifetime Version (K-SADS-PL) was higher than a similar study. Moreover, in this study, among the five provinces, Tehran and Mashhad allocated the highest rates of ODD; Isfahan and Shiraz had the highest rates of ADHD; and Tabriz had the highest rates of social phobia. Therefore, these percentage of psychiatric disorders in Iran lead us toward a greater use of consultation and mental health services

Understanding and examining teacher resilience from multiple perspectives

In this chapter, I argue that differing conceptualisations of the construct of resilience shape and enrich the research questions and methodology used to examine it. In addition, the conceptual focus has implications for questions such as whose responsibility it is for the development of resilience. Research conducted within two Australian projects, Keeping Cool and BRiTE (Building Resilience in Teacher Education) is used as an illustration of the impact of a changing conceptual focus. For example, beginning with a psychological perspective led to an examination of risk and protective factors for individuals. More contextual approaches involved a comparison of countries. Recent systemic views support a model that encompasses both personal and contextual characteristics, as well as strategies used and outcomes achieved. It is argued that taking multiple perspectives in this programme of work has enabled the incorporation of a broad range of research methods and findings, and contributed to a deeper understanding of the construct of teacher resilience