INFLUENCE OF INJECTOR OPENING PRESSURE ON EXHAUST EMISSIONS IN DI DIESEL ENGINE WITH THREE LEVELS OF INSULATION WITH DIESEL OPERATION

ABSTRACT Experiments were conducted to study exhaust emissions of direct injection (DI) diesel engine with different levels of low heat rejection (LHR) combustion chamber such as i) ceramic coated cylinder head, ii) air gap insulated piston and air gap insulated liner and iii) ceramic coated cylinder head along with air gap insulation with pure diesel operation with varied injector opening pressure. Exhaust emissions of particulate emissions and oxides of nitrogen (NO x ) were determined at various values of brake mean effective pressure (BMEP) of the engine. Particulate emissions were measured by AVL Smoke meter, while NO x by Netel Chromatograph NO x analyzer. Engine with different versions of the combustion chamber showed comparable particulate emissions, while they increased NO x emissions drastically at full load operation of the engine, when compared with conventional engine. Engine with air gap insulated piston and air gap insulated liner showed lower NO x levels at 80% of the full load operation. However, exhaust emissions reduced with an increase of injector opening pressure with different versions of the combustion chamber

Optimization of Linear Arrays using Modified Social Group Optimization Algorithm

354-359In this paper, optimization of the linear array (LA) antenna is performed using modified social group optimization algorithm (SGOA). First step of the work involves in transforming the electromagnetic engineering problem to an optimization problem which is completely described in terms of objectives. Linear array synthesis is inherently considered as a multi-attribute problem. The pattern synthesis of LA is carried out with several objectives involving sidelobe level (SLL), beam-width (BW) and desired nulls. The SLL suppression with BW constraint is considered as first objective of this work and the results are compared with several evolutionary computing algorithms like ant lion (ALO), grey wolf (GWO) and root-runner (RRA). Following this, the MSGOA is further used to synthesise null patterns in which the pattern is completely described in terms of nulls with SLL and BW as constraints. The entire simulation-based experimentation is performed using Matlab® on i5 computing system

Explicit kinetic heterogeneity: mechanistic models for interpretation of labeling data of heterogeneous cell populations

Estimation of division and death rates of lymphocytes in different conditions is vital for quantitative understanding of the immune system. Deuterium, in the form of deuterated glucose or heavy water, can be used to measure rates of proliferation and death of lymphocytes in vivo. Inferring these rates from labeling and delabeling curves has been subject to considerable debate with different groups suggesting different mathematical models for that purpose. We show that the three models that are most commonly used are in fact mathematically identical and differ only in their interpretation of the estimated parameters. By extending these previous models, we here propose a more mechanistic approach for the analysis of data from deuterium labeling experiments. We construct a model of "kinetic heterogeneity" in which the total cell population consists of many sub-populations with different rates of cell turnover. In this model, for a given distribution of the rates of turnover, the predicted fraction of labeled DNA accumulated and lost can be calculated. Our model reproduces several previously made experimental observations, such as a negative correlation between the length of the labeling period and the rate at which labeled DNA is lost after label cessation. We demonstrate the reliability of the new explicit kinetic heterogeneity model by applying it to artificially generated datasets, and illustrate its usefulness by fitting experimental data. In contrast to previous models, the explicit kinetic heterogeneity model 1) provides a mechanistic way of interpreting labeling data; 2) allows for a non-exponential loss of labeled cells during delabeling, and 3) can be used to describe data with variable labeling length

Performance of a Low Heat Rejection Diesel Engine With Air Gap Insulated Piston

Introduction The second law requirement of Thermodynamics necessitates the inevitable heat loss to the coolant to realise work output. Any saving in this part of the energy distribution would either increase the energy lost through exhaust gases or increase the power output. Considerable efforts are under way to reduce heat loss to the coolant by various researchers. However, the results are a little confusing as to whether the insulation would improve or deteriorate thermal efficiency. The two approaches that are being pursued to decrease heat rejection are (1) ceramic coating and (2) air gap insulation. Both these methods are still having problems. Ceramic coatings are found to be peeling off over a period of operation. There are serious problems of leakage of gases in the case of air gap insulation. A two zone combustion model was used by A study of the existing literature on LHR engines thus reveal

Efficient Allocation of Power Resource in OFDMA Systems with Diverse Modulation Techniques

ABSTRACT: Of late there is an utmost need for providing higher data rate and better Quality of Service(QoS) for ever increasing number of users in wireless communication systems. The Orthogonal Frequency Division Multiplexing (OFDM) is one of the leading candidates for future wireless communication systems. This paper gives a brief introduction about OFDMA and discusses in depth about allocation of power resource to all the active users present in a cellular network in an optimum way using the Load Matrix approach. Load Matrix approach is used to calculate the average interference within the cells based on RoT (Rise over Thermal noise) and distribute minimum required SINR to each user thereby enhancing the Quality of Service (QoS) of the network. The approach is first experimented on a single carrier communication system and then it is extended to multi-carrier systems. This paper also deals with the performance of a communication link in terms of BER for various digital modulation techniques. From simulations it is observed that performance of QAM is better than QPSK in systems implementing OFDMA

Killing of Targets by CD8+ T Cells in the Mouse Spleen Follows the Law of Mass Action

It has been difficult to correlate the quality of CD8 T cell responses with protection against viral infections. To investigate the relationship between efficacy and magnitude of T cell responses, we quantify the rate at which individual CD8 effector and memory T cells kill target cells in the mouse spleen. Using mathematical modeling, we analyze recent data on the loss of target cells pulsed with three different peptides from the mouse lymphocytic choriomeningitis virus (LCMV) in mouse spleens with varying numbers of epitope-specific CD8 T cells. We find that the killing of targets follows the law of mass-action, i.e., the death rate of individual target cells remains proportional to the frequency (or the total number) of specific CD8 T cells in the spleen despite the fact that effector cell densities and effector to target ratios vary about a 1000-fold. The killing rate of LCMV-specific CD8 T cells is largely independent of T cell specificity and differentiation stage. Our results thus allow one to calculate the critical T cell concentration at which growth of a virus with a given replication rate can be prevented from the start of infection by memory CD8 T cell response

An Interpretive Phenomenological Analysis (IPA) of coercion towards community dwelling older adults with dementia: Findings from MYsore studies of Natal effects on Ageing and Health (MYNAH)

The final publication is available at Springer via http://dx.doi.org/10.1007/s00127-016-1286-4Purpose Limited availability of specialist services places a considerable burden on caregivers of Persons with Dementia (PwD) in Low- and Middle-Income Countries (LMICs). There are limited qualitative data on coercive behavior towards PwD in an LMIC setting. Aim The aim of this study was to find relevant themes of the lived experience of relatives as caregivers for PwD in view of their use of coercive measures in community setting in South India. Method Primary caregivers (n = 13) of PwDs from the Mysore study of Natal effects on Ageing and Health (MYNAH) in South India were interviewed to explore the nature and impact of coercion towards community dwelling older adults with dementia. The narrative data were coded using an Interpretative Phenomenological Analysis (IPA) approach for thematic analysis and theory formation. Results Caregivers reported feeling physical and emotional burn-out, a lack of respite care, an absence of shared caregiving arrangements, limited knowledge of dementia, and a complete lack of community support services. They reported restrictions on their lives through not being able take employment, a poor social life, reduced income and job opportunities, and restricted movement that impacted on their physical and emotional well-being. Inappropriate use of sedatives, seclusion and environmental restraint, and restricted dietary intake, access to finances and participation in social events, was commonly reported methods of coercion used by caregivers towards PwD. Reasons given by caregivers for employing these coercive measures included safeguarding of the PwD and for the management of behavioral problems and physical health. Conclusion There is an urgent need for training health and social care professionals to better understand the use of coercive measures and their impact on persons with dementia in India. It is feasible to conduct qualitative research using IPA in South India

Linear Fidelity in Quantification of Anti-Viral CD8+ T Cells

Enumeration of anti-viral CD8+ T cells to make comparisons between mice, viruses and vaccines is a frequently used approach, but controversy persists as to the most appropriate methods. Use of peptide-MHC tetramers (or variants) and intracellular staining for cytokines, in particular IFNγ, after a short ex vivo stimulation are now common, as are a variety of cytotoxicity assays, but few direct comparisons have been made. It has been argued that use of tetramers leads to the counting of non-functional T cells and that measurement of single cytokines will fail to identify cells with alternative functions. Further, the linear range of these methods has not been tested and this is required to give confidence that relative quantifications can be compared across samples. Here we show for two acute virus infections and CD8+ T cells activated in vitro that DimerX (a tetramer variant) and intracellular staining for IFNγ, alone or in combination with CD107 to detect degranulation, gave comparable results at the peak of the response. Importantly, these methods were highly linear over nearly two orders of magnitude. In contrast, in vitro and in vivo assays for cytotoxicity were not linear, suffering from high background killing, plateaus in maximal killing and substantial underestimation of differences in magnitude of responses

Population mechanics: A mathematical framework to study T cell homeostasis

Unlike other cell types, T cells do not form spatially arranged tissues, but move independently throughout the body. Accordingly, the number of T cells in the organism does not depend on physical constraints imposed by the shape or size of specific organs. Instead, it is determined by competition for interleukins. From the perspective of classical population dynamics, competition for resources seems to be at odds with the observed high clone diversity, leading to the so-called diversity paradox. In this work we make use of population mechanics, a non-standard theoretical approach to T cell homeostasis that accounts for clone diversity as arising from competition for interleukins. The proposed models show that carrying capacities of T cell populations naturally emerge from the balance between interleukins production and consumption. These models also suggest remarkable functional differences in the maintenance of diversity in naïve and memory pools. In particular, the distribution of memory clones would be biased towards clones activated more recently, or responding to more aggressive pathogenic threats. In contrast, permanence of naïve T cell clones would be determined by their affinity for cognate antigens. From this viewpoint, positive and negative selection can be understood as mechanisms to maximize naïve T cell diversity

IL-2 Mediates CD4+ T Cell Help in the Breakdown of Memory-Like CD8+ T Cell Tolerance under Lymphopenic Conditions

Background: Lymphopenia results in the proliferation and differentiation of naïve T cells into memory-like cells in the apparent absence of antigenic stimulation. This response, at least in part due to a greater availability of cytokines, is thought to promote anti-self responses. Although potentially autoreactive memory-like CD8 + T cells generated in a lymphopenic environment are subject to the mechanisms of peripheral tolerance, they can induce autoimmunity in the presence of antigen-specific memory-like CD4 + T helper cells. Methodology/Principal Findings: Here, we studied the mechanisms underlying CD4 help under lymphopenic conditions in transgenic mice expressing a model antigen in the beta cells of the pancreas. Surprisingly, we found that the self-reactivity mediated by the cooperation of memory-like CD8 + and CD4 + T cells was not abrogated by CD40L blockade. In contrast, treatment with anti-IL-2 antibodies inhibited the onset of autoimmunity. IL-2 neutralization prevented the CD4-mediated differentiation of memory-like CD8 + T cells into pathogenic effectors in response to self-antigen cross-presentation. Furthermore, in the absence of helper cells, induction of IL-2 signaling by an IL-2 immune complex was sufficient to promote memory-like CD8 + T cell self-reactivity. Conclusions/Significance: IL-2 mediates the cooperation of memory-like CD4 + and CD8 + T cells in the breakdown of crosstolerance, resulting in effector cytotoxic T lymphocyte differentiation and the induction of autoimmune disease