Computer simulation of a batch distillation column with a reflux divider

The operation of a batch distillation column with a reflux divider has been mathematically simulated to reproduce operational equipment. The operation of the column consists of one or more product recoveries. During each product recovery period the column alternates between total reflux and total product withdrawal, with the product withdrawal period being 2 — 5 seconds. Between product recoveries the column operating conditions can be reset. The basic assumption of this batch distillation simulation is that the column completely equilibrates during the period of total reflux. The determination of the total reflux condition is obtained computationally using the iterative Newton—Raphson method. The significant feature of this simulation is the ability to handle a constant volumetric inventory associated with each contact stage. Two illustrative examples are included to show the capabilities of the batch distillation simulation. The first consists of a four component chlorinated benzene system. The second example simulated the recovery of acetonitrile from the highly non—ideal water — acetonitrile binary system

Participation and Protest: Non-Governmental Organisations and Philippine Politics.

Since the late 1980s, a significant number of studies of the work of Non-Governmental Organisations (NGOs) in the developing world have been published, giving rise to a distinctive literature within the social sciences. This literature however focuses on the socioeconomic aspects of NGO action and is of limited use to political scientists in interpreting the "associational revolution" triggered by the proliferation of NGOs in Asia, Africa and Latin America in recent decades. Michael Bratton has argued that it is in the political sphere rather than the economic that the contributions of NGOs to development should be mainly seen, yet political scientists have failed to contribute proportionately to the evolving NGO literature. Following Bratton, this dissertation examines the role of NGOs in Philippine politics, especially since the collapse of the Marcos dictatorship in February 1986. The dissertation examines the history of Philippine NGO participation in politics, relations between NGOs and the Philippine state since 1986, the institutional forces promoting the proliferation of NGOs, and the main mechanisms through which NGOs engage in politics. Case-studies of two of the Philippines' leading NGOs elaborate on the general arguments from early chapters and reveal that NGO strategy is characterised by a complex blend of participation and protest shaped by the policies of a succession of regimes throughout the late twentieth century. Between 1984 and 1993, the number of NGOs in the Philippines grew by 148%. This growth raises important questions about the nature of NGO action and its impact on Philippine politics, the state, and civil society. Does the NGO community strengthen civil society? Can it transform relations between the state and civil society? Can it help to empower the millions traditionally marginalised from political participation in the Philippines? On the first question, the dissertation argues that NGOs simultaneously weaken and strengthen civil society and that the NGO community is best seen as a new arena within which battles from society at large are internalized. On the second, it argues that collaboration between NGOs and the state has strengthened the state in small yet significant ways, helping it to attack entrenched socio-economic elite interests and helping the state to attract broad-based popular support for far-reaching political and economic reforms. On the third question, the dissertation argues that expanding political participation has been one of the main achievements of the Philippine NGO community and that NGOs, by linking with grass-roots "people's organisations", have filled an important institutional vacuum resulting from the inability of political parties, trade unions and peasant associations to promote sustained popular political participation. The main significance of growth in the Philippine NGO community is political. As the dissertation argues throughout, the proliferation, regional distribution and organisational character of NGOs, as well as the tasks they perform and the posture they adopt vis-a-vis state agencies and the private sector, have all been determined by essentially political factors. Philippine NGOs and the people's organisations with which they work closely are significant mainly for their broad organisational reach and their ability to organise and mobilise around ideologically-coherent interests, hence making them an important actor in Philippine politics

Energy and carbon performance of housing : upgrade analysis, energy labelling and national policy development

The area of policy formulation for the energy/carbon performance of housing is coming under increasing focus. A major challenge is to account for the large variation within national housing stocks relative to factors such as location, climate, age, construction, previous upgrades, appliance use and heating/cooling system types. Existing policy oriented tools rely on static calculation models that have limited ability to represent building behaviour and the impact of future changes in climate and technology. The switch to detailed simulation tools to address these limitations in the context of policy development has hitherto been focussed on the modelling of a small number of representative designs rather than dealing with the spread inherent in large housing stocks. To address these challenges, the ESRU Domestic Energy Model (EDEM) has been developed as a Web based tool built on detailed simulation models that have been aligned with the outcomes of national house condition surveys. On the basis of pragmatic inputs, EDEM is able to determine energy use and carbon emissions at any scale – from an individual dwelling to national housing stocks. The model was used at the behest of the Scottish Building Standards Agency and South Ayrshire Council to determine the impact of upgrades and the deployment of new and renewable energy systems. EDEM was also used to rate the energy/carbon performance of individual dwellings as required by the EU Directive on the Energy Performance of Buildings (EU, 2002). This paper describes the EDEM methodology and presents the findings from applications at different scales

The gut microbiome and pharmacology: a prescription for therapeutic targeting of the gut-brain axis

New frontiers for host-microbe interactions continue to emerge as our knowledge of the adult gut microbiome in health and disease is continually supplemented and improved. Alterations in the gut microbiota composition in irritable bowel syndrome (IBS) are now linked to symptom severity while population-based evidence linking gut microbiome signatures to depression is an important new landmark. The effects of drugs on gut microbiome composition are also becoming clearer. Meanwhile, preclinical studies have delineated the influence of the gut microbiome at a structural and activity level in distinct brain regions. Bacterial metabolites, such as tryptamine, can activate specific receptors to impact gastrointestinal motility. These recent studies bring into focus the future implications for therapeutic targeting of the microbiomeâ gutâ brain axis

The thermal simulation of an office building implementing a new behavioural algorithm for window opening and the use of ceiling fans

This investigation of the window opening data from extensive field surveys in UK office buildings investigates 1) how people control the indoor environment by opening windows, 2) the cooling potential of opening windows, and 3) the use of an “adaptive algorithm” for predicting window opening behaviour for thermal simulation in ESP-r. We found that the mean indoor and outdoor temperatures when the window was open were higher than when it was closed, but show that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys

A window opening algorithm and UK office temperature field results and thermal simulation

This investigation of the window opening data from extensive field surveys in UK office buildings investigates 1) how people control the indoor environment by opening windows, 2) the cooling potential of opening windows, and 3) the use of an “adaptive algorithm” for predicting window opening behaviour for thermal simulation in ESP-r. We found that the mean indoor and outdoor temperatures when the window was open were higher than when it was closed, but show that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys

The kynurenine pathway: towards metabolic equilibrium

No abstract available

Strategies for low carbon buildings : Assessment of design options and the translation of design intent into performance in practice

To deliver low carbon buildings requires: a) Performance assessment and option appraisal; b) Industry process to translate selected options into low carbon performance in practice. This thesis aims to make some contribution in each of these two areas. Legislation such as the European Performance of Buildings Directive (EPBD) is stimulating the market to put forward many technical options for design or retrofit of low carbon buildings. The need is identified here for a low cost, EPBD compatible, simulation based, real time method for performance assessment and upgrade option appraisal to inform decisions for a range of users with various levels of technical knowledge. The hypothesis is advanced that such a method can be developed. An EPBD compatible, dynamic simulation based, real time, performance assessment and option appraisal method is then proposed and evaluated. A range of test applications and user groups are considered. Test applications include the generation of energy performance ratings based on a simple questionnaire. Other applications cover a range of individual building, policy or strategy contexts. A critical analysis is carried out of the applicability, scope and limitations of the method. The proposed method proved useful in a range of applications. For other applications some limitations were identified. How these can be addressed is discussed. The development and deployment examples are for a specific building stock but provide insights to enable replication for other situations. The research provides a foundation for further research and development. There is much evidence that selection of appropriate options is not sufficient to achieve low carbon performance. Many issues can lead to gaps between intended and actual performance. Problems are identified in the design and implementation of low carbon systems and controls. Problems include poor understanding, errors in implementation, and poor visibility of actual performance. The need for a method to address these problems is identified. The hypothesis is advanced that such a method can be developed. A Modular Control Mapping and Failure Mode Effect Analysis (FMEA) method is then proposed and evaluated for a range of test applications to buildings intended to be low carbon. The insights from the test applications are reviewed and the scope and limitations of the proposed method discussed. Overall the applications were successful and the useful application demonstrated. The method was deployed post-occupancy, then applicability at various stages of the design process was demonstrated by using concept and detailed design information. The modular control mapping and FMEA process proposed leverages in part the approach taken in industrial sectors identified as benchmarks by proponents of the Building Information Modelling (BIM) initiative. The potential application of further processes from BIM benchmark industry is discussed in the context of current buildings industry initiatives. The performance assessment and option appraisal method, the modular control mapping and FMEA method, and the outcomes from their evaluations are intended to contribute to the realisation of low carbon buildings in practice. The future integration of both methods within a BIM framework is proposed

Characterization of bulk and surface currents in strain-balanced InGaAs quantum-well mesa diodes

We compare the electrical and optical characteristics of mesa diodes based on In0.62Ga0.38As/In0.45Ga0.55As strain-balanced multiple-quantum wells (SB-MQW) with lattice-matched (LM) In0.53Ga0.47As diodes. The dark current density of the SB-MQW devices is at least an order of magnitude lower than the LM devices for voltages >0.4 V. Sidewall recombination current is only measured on SB-MQW diodes when exposed to a damaging plasma. While radiative recombination current dominates in the SB-MQW diodes, it is less than the diffusive current in the LM diodes for the same applied voltage. (C) 2004 American Institute of Physics. (DOI:10.1063/1.1835537