Optimisation of autoselective plasma regeneration of wall-flow diesel particulate filters

The increase in number of diesel powered vehicles has led to greater concern for the effects of their exhaust emissions. Engine manufacturers must now consider using diesel particulate filters to make their engines meet the legislated limits. Diesel particulate filters can remove more than 95% of the particulates from the exhaust flow but require cleaning, known as regeneration. This thesis describes the research and optimisation of the Autoselective regeneration system for cordierite wall flow diesel particulate filters. The novel Autoselective technology uses an atmospheric pressure glow discharge plasma to selectively oxidise particulate matter (soot) trapped within the filter. The aim of this research was to produce a regeneration system that can operate under all exhaust conditions with a low energy demand and no precious metal dependence to compete with the numerous pre-existing technologies. The effect of discharge electrode type and position on regeneration performance has been investigated in terms of regeneration uniformity, power requirement and regeneration rate. The results showed that the electrode orientation had a large effect on regeneration distribution and energy demand. The electrode capacitance and breakdown voltage was shown to affect the choice of power supply circuit because not all power supply topologies were suitable for powering electrodes with >100 pF capacitance. A number of power supplies were designed and tested, a voltage driven resonant transformer type supply was shown to be optimal when used in conjunction with a swept frequency. The current and frequency ranges of electrical discharges were continuously variable, and their effect on discharge regeneration performance was studied. The results showed that the discharge frequency had no effect on the regeneration process but did affect spatial distribution. An optimised resonant transformer power supply was designed that was ideally suited for the electrodes used. A novel power modulation strategy, which used a switching frequency phase locked to the ~ iii ~ modulating frequency, was employed which extended the operating range of the discharge to below 10 mA for electrode separations > 7.5 mm. The heat flows within the filter and discharge during regeneration were analysed and the filter damage process was linked to the heat released by the discharge inside the filter wall. Other filter materials were compared based on the findings and Mullite ceramic was identified as a potentially better filter material for Autoselective regeneration. The filtration efficiency is important and was observed to be affected by the Autoselective process. The effect of the discharge on filtration efficiency was studied and the mechanism of particulate re-entrainment was identified as a combination of electrostatic and electro-acoustic forces. The Autoselective technology was successfully implemented in both flow-rig and on-engine tests. Results showed significant reduction in back-pressure for power inputs of ~ 500 W. The understanding of the Autoselective regeneration system has been improved and the research resulted in a novel method of filter regeneration

Visualizing the Structure of Large Trees

This study introduces a new method of visualizing complex tree structured objects. The usefulness of this method is illustrated in the context of detecting unexpected features in a data set of very large trees. The major contribution is a novel two-dimensional graphical representation of each tree, with a covariate coded by color. The motivating data set contains three dimensional representations of brain artery systems of 105 subjects. Due to inaccuracies inherent in the medical imaging techniques, issues with the reconstruction algo- rithms and inconsistencies introduced by manual adjustment, various discrepancies are present in the data. The proposed representation enables quick visual detection of the most common discrepancies. For our driving example, this tool led to the modification of 10% of the artery trees and deletion of 6.7%. The benefits of our cleaning method are demonstrated through a statistical hypothesis test on the effects of aging on vessel structure. The data cleaning resulted in improved significance levels.Comment: 17 pages, 8 figure

Organización lipídica de la membrana celular

Lipids and proteins in biological membranes are arranged in a mosaic of domains in the membrane. These domains represent small-scale heterogeneities in composition, shape and fluidity within the plane of the membrane, over the range of hundreds of nanometers to a few micrometers. They arise from the complex interactions of the heterogeneous mixtures of phospholipids, sterols, and proteins that make up all biological membranes.Los lípidos y las proteínas en las membranas biológicas están dispuestos en un mosaico de campos en la membrana. Estos campos representan heterogeneidades a pequeña escala en la composición, forma y fluidez dentro del plano de la membrana, en un rango que va de los cientos de nanómetros a los pocos micrómetros. Estos campos se originan de las complejas interacciones de las mezclas heterogéneas de fosfolípidos, esteroles y proteínas de las que están hechas todas y cada una de las membranas biológicas

Human immunodeficiency virus-1 Nef protein interacts with Tat and enhances HIV-1 gene expression

AbstractThe human immunodeficiency virus (HIV-1) Nef protein is now regarded as a regulatory protein responsible not only for establishment of infection and increased pathogenesis but also for enhancement of viral replication. However, the mechanism of Nef-induced activation of viral replication remains to be clearly understood. Using transient transfection assay, co-immunoprecipitation and pull-down analysis, we demonstrate in this report that the HIV-1 Nef protein physically interacts with Tat, the principal transactivating protein of HIV-1. Our observations with single cycle replication experiments further indicate that this interaction results not only in enhancement of Tat-induced HIV-1 long terminal repeat-mediated gene expression but also in virus production

Case report on heavy eye syndrome

In high myopia, acquired esotropia can be present as strabismus fixus convergence also known as Heavy Eye Syndrome (HES). Although exotropia and hypertropia have been reported, patients typically present with diplopia due to increasing esotropia and hypotropia with limitations on abduction and elevation. We reported two cases of HES based on history and clinical examination, which includes anterior and posterior segment examination and squint evaluation. The MRI of both patients showed displacement of lateral rectus inferiorly and nasal shifting of superior rectus. In both the cases forced duction test (FDT) was positive for affected medial rectus (MR) when performed under local anaesthesia. Subsequently, they underwent loop myopexy of superior rectus (SR) with medical rectus (MR) along with MR recession for affected eye. Postoperatively, Case 1 had a residual esotropia of 18 prism dioptre (PD) and case 2 had 40 PD compare to preoperatively 70 and 80 PD respectively, measured with the krimsky test. Axial length lengthening and herniation of sclera between the SR and LR muscles are the two main contributors to HES. To stop additional herniation, the inter-muscular link must be restored. Loop myopexy is an elegant and effective procedure to achieve good cosmetic and functional results for HES

Codifying healthcare – big data and the issue of misclassification

The rise of electronic medical records has led to a proliferation of large observational studies that examine the perioperative period. In contrast to randomized controlled trials, these studies have the ability to provide quick, cheap and easily obtainable information on a variety of patients and are reflective of everyday clinical practice. However, it is important to note that the data used in these studies are often generated for billing or documentation purposes such as insurance claims or the electronic anesthetic record. The reliance on codes to define diagnoses in these studies may lead to false inferences or conclusions. Researchers should specify the code assignment process and be aware of potential error sources when undertaking studies using secondary data sources. While misclassification may be a short-coming of using large databases, it does not prevent their use in conducting meaningful effectiveness research that has direct consequences on medical decision making

Immune Modulation in the Treatment of Amyotrophic Lateral Sclerosis: A Review of Clinical Trials

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the degeneration of motor neurons. Though many molecular and genetic causes are thought to serve as predisposing or disease propagating factors, the underlying pathogenesis of the disease is not known. Recent discoveries have demonstrated the presence of inflammation propagating substrates in the central nervous system of patients afflicted with ALS. Over the past decade, this hypothesis has incited an effort to better understand the role of the immune system in ALS and has led to the trial of several potential immune-modulating therapies. Here, we briefly review advances in the role of such therapies. The clinical trials discussed here are currently ongoing or have been concluded at the time of writing

Weeds and weed control in finger millet in India - A review

Eleusine coracana (L.) Gaertn is a nutritious and under exploited minor millet with several edible and industrial uses. Finger millet is cultivated on 1.176 million ha, with average yields of 1.64 t/ha, in India (DMD), 2014)..

Increasing input resources use efficiency through appropriate weed management in Indian agriculture

Indian agriculture plays a major role in the country’s economy with 60% of India’s population depending on agriculture sector. The central concern of Indian agriculture is low productivity, evident in modest average crop yields. India may need at least 20 million tons of additional food every year to meet the minimum food and nutritional demands of the growing population which is expected to be 1.7 billion by 2050. Thus the greatest challenge for Indian agriculture is to produce more with minimal input resources without causing imbalance to environment and in a sustainable manner. One of the approaches to face the challenge is production of crops with increased input resource use efficiency by managing impediments such as weeds, which are adaptable to all adverse environments and compete with the crops for utilization of land, labor, light, nutrients and water resources (Yaduraju and Rao 2013). In this presentation, an effort is made to give an overall picture of resources used in Indian agriculture, extent of competition by weeds for resources with crops and extent of losses caused by weeds and appropriate weed management strategies for enhancing input resources use efficiency of crops for attaining increased crop productivity and production to meet the present and future demands of Indian population