Investigation and optimisation of commercial refrigeration cycles using the natural refrigerant CO2

This thesis was submitted for the degree of Doctor of Engineering and awarded by Brunel University.With tighter regulations on the use of Hydroflurocarbons (HFCs) due to their high GWP (Global Warming Potential), many supermarket operators are looking for alternative refrigerants. To contribute to this, the objectives of this thesis are to investigate the practicality, environmental benefits and economic viability of an all-CO2 transcritical refrigeration system suitable for small supermarkets. Whilst the environmental benefits of using CO2 as a refrigerant are clear, there is rather limited practical and technical knowledge on the design and operation of these systems. In this work, simulation models of a transcritical ‘booster’ CO2 refrigeration system have been developed to investigate and evaluate its performance against that of a traditional HFC system. The models were verified using test results from an experimental CO2 system built at Brunel University. To evaluate the performance of the CO2 refrigeration system in the field, energy data from a real supermarket employing a HFC refrigeration system was used for energy simulations. The results demonstrate that the annual energy consumption of the CO2 refrigeration system in a small supermarket in Northern Ireland would be equivalent to that of a typical HFC refrigeration system. However, the low GWP of CO2 will result in a 50% reduction in the combined direct and indirect CO2 emissions over the operational life of the system assuming an annual leakage rate of 15%. Northern Ireland has a high number of small supermarkets due to its rural population, approximately 615. The CO2 system presented in this research could replace the existing R404A systems in these small supermarkets resulting in emissions reduction of up to 188,752 tCO2e. This research has developed selection techniques and criteria to be considered by supermarket designers and operators when developing national strategies for the eventual phase-out of HFC refrigerants in all supermarket sizes. The validated simulation models developed in this research combined with the detailed geographical and refrigeration load ratio analysis presented, will provide valuable information that will assist system designers and operators in the efficient design and optimisation of CO2 technology for small supermarkets.This study was funded by the Engineering and Physical Sciences Research Council and Shilliday Refrigeration

Potential for Solar Energy in Food Manufacturing, Distribution and Retail

The overall aim of the study was to assess the potential for increasing the use of solar energy in the food sector. For comparative purposes the study also included an assessment of the benefits that could arise from the use of other renewable energy sources, and the potential for more effective use of energy in food retail and distribution. Specific objectives were to: i) establish the current state of the art in relevant available solar technology; ii) identify the barriers for the adoption of solar technology; iii) assess the potential for solar energy capture; iv) appraise the potential of alternative relevant technologies for providing renewable energy; v) assess the benefits from energy saving technologies; vi) compare the alternative strategies for the next 5-10 years and vii) Consider the merits of specific research programmes on solar energy and energy conservation in the food sector. To obtain the views of the main stakeholders in the relevant food and energy sectors on the opportunities and barriers to the adoption of solar energy and other renewable energy technologies by the food industry, personal interviews and structured questionnaires tailored to the main stakeholders (supermarkets, consultants for supermarket design; energy and equipment suppliers) were used. The main findings from the questionnaires and interviews are: - Key personnel in supermarkets and engineers involved in the design of supermarkets are aware of the potential contribution of renewable energy technologies and other energy conservation measures to energy conservation and environmental impact reduction in the food industry. A number of supermarket chains have implemented such technologies at pilot scale to gain operating experience, and more importantly, for marketing reasons, to gain competitive advantage through a green image. - From installations to date in the UK the most notable are a 600 kW wind turbine at a Sainsbury's distribution centre in East Kilbride and a 60 kWp photovoltaic array at a Tesco store in Swansea. - The main barrier to the application of renewable energy technologies in the food sector is the capital cost. Even though significant progress has been made towards the improvement of the energy conversion efficiencies of photovoltaic technologies (PVs) and reduction in their cost, payback periods are still far too long, for them to become attractive to the food industry. - Wind energy can be more attractive than PVs in areas of high wind speed. Apart from relatively high cost, the main barrier to the wide application of wind turbines for local power generation is planning restrictions. This technology is more attractive for application in food distribution centres that are normally located outside build-up areas where planning restrictions can be less severe than in urban areas. In these applications it is likely that preference will be for large wind turbines of more than 1.0 MW power generation capacity as the cost of generation per unit power reduces with the size of the turbine

Aspects of Fijian syntax: a GPSG analysis

This thesis presents a basic Generative Grammar for the Fijian language. To be more precise it presents a grammar for the dialect spoken by Rev. Samuela Tamata, a native of the island of Kadavu. The data gathered from my informant supplemented (and typically confirmed) two non-Generative Grammars of Fijian which were at my disposal. These were Milner (1956) and Schuetz (1985). The former is a paedogogical work aimed at acquainting the beginner with the rudiments of Fijian. The latter provides a comprehensive description of the Fijian language based on extensive recent survey work. Unfortunately only a fraction of this work is devoted to sentence structure, the subject of this thesis.After setting the linguistic and non-linguistic background in Chapter 1, I proceed to outline the Generative Grammar which I assume for the majority of the thesis, namely Generalized Phrase Structure Grammar as presented by Gazdar et al. (1985).Chapter 3 then presents several revisions of the standard model. These were principally motivated by aspects of Fijian syntax e.g. the revision of the Subcategorization mechanism in the light of Object agreement on Verbs and the rejection of Slash Termination Metarules so that Unbounded Dependencies could terminate in Subject position.Chapter 4 provides a detailed analysis of the four subclasses of Noun i.e. Names, Pronouns, Common Nouns and Numerals. This is followed by an examination of Person and Number in conjoined Noun Phrases, a topic of particular interest to GPSG.Chapter 5 proceeds to an examination of various NP modifiers such as Adjective Phrases, Prepositional Phrases and Relative Clauses. The internal structure of Relative Clauses is however taken up in Chapter 8.Chapter 6 outlines the structure of the Fijian clause and comes to the perhaps surprising conclusion for a GPSG analysis that the Sentence is a projection from the Inflection rather than the Verb. (This IP analysis is however advocated in the Government and Binding theory of Chomsky (1986)).Chapter 7 attempts to deal with the variations in phrase ordering in Fijian. This involves firstly the introduction of a second [SLASHj-like feature to account for double extractions and secondly the positing of twin heads in flat VSO structures.In Chapter 8 we turn to Fijian Unbounded Dependencies, principally Topicalization and Relativization. We here present the evidence which led to our rejection of Slash Termination Metarules in Chapter 3 and argue against the need for the [WH] feature in Fijian Relative Clauses or Constituent Questions.CChapter 9 outlines the two raising constructions in Fijian; Subject-to-Subject Raising with impersonal verbs such as RAWA "possible" and Subject-to-Object Raising with verbs such as NUITAKA "expect". The latter construction is of particular interest since the rival Government and Binding theory claims that it is universally unacceptable!In Chapter 10 I change theoretical frameworks and present Government and Binding analyses of two topics of particular interest to that theory; namely multiple adjunction structures and Head-to-Head movement.Finally the Appendix includes a suggestion for an alternative Head Feature Convention for GPSG which operates on a more constrained notion of "Free Head Feature"

Assessing the Personal Needs and Professional Issues that Hinder Credentialed Women in the Ohio Ministry Network: Egalitarianism and the Image of God

The purpose of this study was to discover if some local Assemblies of God (A/G) church practices differed from the denominational egalitarian theology. Credentialed women from the Ohio Ministry Network (OMN), a district of the General Council of the Assemblies of God, were surveyed. According to the survey results, time management, representation at OMN events, ministry connections, and exclusion from the leadership pipeline are the greatest challenges for credentialed women. The goal of promoting awareness of the personal needs and professional issues of credentialed women was actualized by integrating the literature review of imago Dei theology with an Ohio School of Ministry class and a mid-week sermon

Development of an Accelerated Test Design for Predicting the Service Life of the Solar Array at Mead, Nebraska

Potential long-term degradation modes for the two types of modules in the Mead array were determined and judgments were made as to those environmental stresses and combinations of stresses which accelerate the degradation of the power output. Hierarchical trees representing the severity of effects of stresses (test conditions) on eleven individual degradation modes were constructed and were pruned of tests judged to be nonessential. Composites of those trees were developed so that there is now one pruned tree covering eight degradation modes, another covering two degradation modes, and a third covering one degradation mode. These three composite trees form the basis for selection of test conditions in the final test plan which is now being prepared

Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

From Springer Nature via Jisc Publications RouterHistory: received 2020-01-31, accepted 2020-06-01, registration 2020-06-01, online 2020-06-16, epub 2020-06-16, collection 2020-12Background: Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis. Methods: Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome. Results: Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76–0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis. Conclusions: Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.21pubpu

A Comparison of Forward and Inverse Simulation Methods for Fault Detection on a Rover

Fault tolerant design is hugely important for autonomous mobile robots such as planetary exploration rovers (PERs), as they are required to be both robust and reliable in extremely harsh environments. One of the main principles of fault tolerance is the detection and diagnosis of any faults afflicting the system. A model-based fault detection procedure is presented using forward and inverse simulation methods. The results of each method are compared for faults in different system locations to display the differences and advantages of both methods. It is shown by this comparison that the methods complement each other and can be used concurrently to diagnose output and input faults

Non-recent Institutional Abuses and Inquiries: Truth, Acknowledgement, Accountability and Procedural Justice

Over the last two decades, historical abuse in state and religiously-operated institutions and some civil society groups and organisations has come under scrutiny around the world. The island of Ireland, comprising Northern Ireland and the Republic of Ireland, has had a large number of investigations, redress schemes or apologies regarding non-recent institutional abuse against women and children, some of which are ongoing. Many of these efforts have been criticised by victims/survivors, academic activists and advocates for deficient processes or inadequate recommendations or outcomes. Despite widespread acknowledgement that recent official responses to non-recent institutional abuse are lacking in terms of their capacity to deliver truth, acknowledgement, accountability, and procedural justice, discourses are rarely informed by detailed empirical assessment of the views of key stakeholders including victims/survivors, victim-advocates/representatives, lawyers and human rights advocates, judges/commissioners, politicians, policymakers and members of churches and religious orders. This is an important moment, therefore, to stand back and assess justice responses to non-recent institutional abuse across the island of Ireland and how they compare to efforts across the world. This research will provide a guiding standard to improve social and public understanding to redress non-recent institutional abuse across Ireland and elsewhere.Higher Education AuthorityTransforming Justice Responses to Historical Institutional Abuse ProjectBritish AcademyUK Arts and Humanities Research Counci