Precision Unification and Proton Decay in F-Theory GUTs with High Scale Supersymmetry

F-theory GUTs provide a promising UV completion for models with approximate gauge coupling unification, such as the (non-supersymmetric) Standard Model. More specifically, if the superparters have masses well above the TeV scale, the resulting imperfection in unification can be accounted for by the, in principle calculable, classical F-theory correction at the high scale. In this paper we argue for the correct form of the F-theory corrections to unification, including KK mode loop effects. However, the price of compensating the imprecise unification in such High Scale SUSY models with F-theory corrections is that the GUT scale is lowered, potentially leading to a dangerously high proton decay rate from dimension-6 operators. We analyse the possibility of suppressing the decay rate by the localization of $X,Y$ gauge bosons in higher dimensions. While this effect can be very strong for the zero modes, we find that in the simplest models of this type it is difficult to realize a significant suppression for higher modes (Landau levels). Notably, in the absence of substantial suppressions to the proton decay rate, the superpartners must be lighter than 100 TeV to satisfy proton decay constraints. We highlight that multiple correlated signals of proton decay could verify this scenario.Comment: 44 pages. v2: References adde

Citizens of Character - The Values and Character Dispositions of 14-16 Year Olds in the Hodge Hill Constituency

Citizens of Character explores the attitudes, dispositions, and values of 14-16 year old students in a particular urban environment - the six schools of the Hodge Hill constituency in Birmingham - and the extent to which the education system and the local environment advance or inhibit their sense of self, their values and their character development. These students constituted a heterogeneous group of religious and non-religious individuals. This project goes beyond the normal exploration and measurement of strengths of character in individuals and looks at the factors that build character in families and schools. This research has wider implications for the relationship between character and aspirations, social change, school cultures, citizenship, identity and religion. The study discusses what students understand by character. It set out to ascertain the moral values held by a group of students living in an inner-city area. The study sought to question who or what has influenced their moral values and examined which individuals, institutions and situations might have hindered or promoted their development. Some of the issues and concerns which arose - for example, relations with neighbours, the matter of local and national pride and questions of trust - may seem not to impinge upon character education as such but are relevant in a wider context

International Comparisons of Work Disability

Self-reported work disability is analyzed in the US, the UK and the Netherlands. Different wordings of the questions lead to different work disability rates. But even if identical questions are asked, cross-country differences remain substantial. Respondent evaluations of work limitations of hypothetical persons described in vignettes are used to identify the extent to which differences in self-reports between countries or socio-economic groups are due to systematic variation in the response scales. Results suggest that more than half of the difference between the rates of self-reported work disability in the US and the Netherlands can be explained by response scale differences. A similar methodology is used to analyze the reporting bias that arises if respondents justify being on disability benefits by overstating their work limiting disabilities

Foundations of Character - Developing Character and Values in the Early Years

Foundations of Character takes a deep and insightful look into character and values development during the 'early years' phase of education. It is commonly assumed that the influences on the early years of a child'slife are determinative for the future individual: the evidence from this report suggests that it is more complex. Children's exposure to and engagement in early childhood education is currently a widespread phenomenon in England, with 92% of three year olds and 98% of four year olds benefitting from some free early years education of up to 15 hours per week. This study aimed to explore the developing dispositions, values and attitudes of a sample of young children in the familiar contexts of their homes, early education settings, and primary schools. It was hoped that this exploration would also provide insights into the values of the significant adults in these children's lives, and these adults' views about the development of character and values

Film cooling in laminar, transitional and turbulent hypersonic boundary layers

Imperial Users onl

Simultaneous Biochar and Syngas Production in a Top-Lit Updraft Biomass Gasifier

Biomass materials can be converted to a wide variety of products, e.g., biochar and syngas through thermochemical conversions. In this study, the thermochemical conversion of biomass residues was carried out in a top-lit updraft gasifier. This gasifier type has been extensively used in developing countries to reduce air pollutants in biomass burning while cooking. However, little literature is found related to the quality and quantification of the products. The goal of this study was to investigate top-lit updraft gasification as a potential alternative to the production of biochar and syngas from biomass residues. The first objective was to understand the effect of the airflow rate and insulation on the overall top-lit updraft gasification process through the quantification of the products and co-products. The results showed that increasing the airflow rate from 8 to 20 lpm proportionally increased the reaction temperature up to 868oC. This increase in temperature negatively impacted the produced biochar which decreased (e.g., from 39.3% to 31.3%, rice hulls – with insulation) with the increase in airflow rate. Little effect in the syngas composition was noticed when varying the airflow, but significant reduction of the tar content (e.g., from 58.7 to 11.8 g/m3, wood chips – without insulation) was observed with the addition of insulation and increase of airflow, enhancing the quality of the produced biochar. The second objective was to investigate the effect of airflow rate and insulation on the properties of the produced biochar. The properties of the biochar were significantly affected by the airflow and the insulation, but their variations were also governed by the properties of the biomass. Due to the large amount of ash in rice hulls (23%), biochar presented decreasing carbon content as the air flow increased, which was opposite to wood chips biochar because of the low ash content in the untreated wood chips (0.57%). In addition, the BET surface area of the biochar increased up to 332 m2 /g when increasing the airflow, but it further increased to 405 m2 /g with the addition of insulation.Biomass materials can be converted to a wide variety of products, e.g., biochar and syngas through thermochemical conversions. In this study, the thermochemical conversion of biomass residues was carried out in a top-lit updraft gasifier. This gasifier type has been extensively used in developing countries to reduce air pollutants in biomass burning while cooking. However, little literature is found related to the quality and quantification of the products. The goal of this study was to investigate top-lit updraft gasification as a potential alternative to the production of biochar and syngas from biomass residues. The first objective was to understand the effect of the airflow rate and insulation on the overall top-lit updraft gasification process through the quantification of the products and co-products. The results showed that increasing the airflow rate from 8 to 20 lpm proportionally increased the reaction temperature up to 868oC. This increase in temperature negatively impacted the produced biochar which decreased (e.g., from 39.3% to 31.3%, rice hulls – with insulation) with the increase in airflow rate. Little effect in the syngas composition was noticed when varying the airflow, but significant reduction of the tar content (e.g., from 58.7 to 11.8 g/m3, wood chips – without insulation) was observed with the addition of insulation and increase of airflow, enhancing the quality of the produced biochar. The second objective was to investigate the effect of airflow rate and insulation on the properties of the produced biochar. The properties of the biochar were significantly affected by the airflow and the insulation, but their variations were also governed by the properties of the biomass. Due to the large amount of ash in rice hulls (23%), biochar presented decreasing carbon content as the air flow increased, which was opposite to wood chips biochar because of the low ash content in the untreated wood chips (0.57%). In addition, the BET surface area of the biochar increased up to 332 m2 /g when increasing the airflow, but it further increased to 405 m2 /g with the addition of insulation