Analyzing of in-cylinder flow structures and cyclic variations of partially premixed combustion in a light duty engine

Partially Premixed Combustion (PPC) strategy offers the potential for simultaneously reduction of NOx and soot emissions with high efficiency. This low temperature combustion strategy involves a proper mixing of fuel and air prior to auto-ignition. During ignition delay (ID) the exact amount of premixing is crucial for the combustion behaviour and emission formation.In this article, high-speed particle image velocimetry (HS-PIV) has been applied to characterise the in-cylinder flow and cycle-to-cycle variations in a light-duty optical engine during fired conditions. The engine is operated at 800 rpm and at a constant CA 50 (~ 8 CAD aTDC). Multiple injections strategies (single, double and triple injections) have been applied to investigate their influence on the flow inside the piston bowl and squish region. The 2D velocity fields are evaluated and investigated over a range of crank angles in the compression and expansion strokes in order to understand the cycle-to-cycle variations. To investigate the problem of cyclic- variations on in-cylinder flows the phase-invariant proper orthogonal decomposition (POD) technique was used. The POD decomposition technique provides a classification method based on an energy criterion by which the mean flow is seen as a superposition of coherent structures. From their temporal coefficients it is possible to characterize its dynamical behaviour

The effects of incubation period and temperature on the Hydrogen sulphide (H2S) technique for detection of faecal contamination in water

A total of 171 water samples from 3 sources were analyzed for the presence of faecal contamination by standard MPN, P/A, EC-M and H2S techniques at different temperatures and incubation times. Analysis of water samples by H2S technique showed that the incubation period of H2S bottles is highly dependent on temperature and concentration of faecal coliform bacteria. Incubation temperature was changed from 22 to 45°C. At higher temperatures (45°C) the bottles turned to black after a 6 h incubation period. Correlation of H2S technique with P/A and MPN techniques were 75.4 and 71%, respectively. Furthermore, the P/A technique showed a correlation of 60.9% with standard MPN technique. In relation to the faecal coliform and by using EC-M technique, we obtained a correlation percentage of 65.1, 56 and 62.3% for standard MPN, H2S and P/A techniques, respectively. This study indicated that incubation period and temperature had significant effects (P = 0.05) on the efficiency of H2S technique. The times when H2S bottles take to turn black is dependent on the number of faecal bacteria, an indicator of the risk that pathogenic organisms are present. Based on the results obtained in this study, we concluded that H2S technique is a reliable method that can be used as an alternative for indication of faecal contamination and drinking water quality surveillance. By using this technique at high t emperatures, rapid screening of large number of water samples in a short period can be profitable especially when the number of drinking water sources is high

Time-resolved in-cylinder PIV measurement in a light duty optical engine under PPC conditions

The understanding of in-cylinder flow field is one of the keys to realize Partially Premixed Combustion (PPC) for internal combustion engines, which has potential to achieve high combustion efficiency with low soot and NOx emissions. In this work, time resolved Particle Image Velocimetry (PIV) was performed to measure the flow field inside the cylinder of a single-cylinder light-duty optical diesel engine.The engine was modified to Bowditch configuration, and was installed with a quartz piston and a transparent cylinder liner, to allow optical access. The geometry of the quartz piston crown is based on the regular combustion chamber design of mass produced diesel engine, including a re-entrant bowl shape. This causes severe distortion on the obtained images, which has to be handled by a distortion correction method before PIV process.The in-cylinder flow structures in a vertical plane at the center of cylinder were obtained both within the piston bowl and within the squish volume, during the compression and expansion stroke. Measurements were performed under three different injection strategies as well as motored engine condition. Both the instantaneous flow field from single cycle and ensemble average flow field calculated from 100 cycles at motored engine condition show a well match with previous studies. The results from fired engine conditions show different Interaction between injected fuel and in-cylinder air at different Crank Angle Degrees (CADs) with different injection strategies.All the results in this study can provide a quantitative dataset being useful to model validation of numerical simulation work to investigate PPC engine more

Model-Based Predictive Control Scheme for Cost Optimization and Balancing Services for Supermarket Refrigeration Systems

A new formulation of model predictive control for supermarket refrigeration systems is proposed to facilitate the regulatory power services as well as energy cost optimization of such systems in the smart grid. Nonlinear dynamics existed in large-scale refrigeration plants challenges the predictive control design. It is however shown that taking into account the knowledge of different time scales in the dynamical subsystems makes possible a linear formulation of a centralized predictive controller. A realistic scenario of regulatory power services in the smart grid is considered and formulated in the same objective as of cost optimization one. A simulation benchmark validated against real data and including significant dynamics of the system are employed to show the effectiveness of the proposed control scheme

Identification and differentiation of Fasciola hepatica and Fasciola gigantica using a simple PCR-restriction enzyme method

Accurate morphological differentiation between the liver fluke species Fasciola hepatica and Fasciola gigantica is difficult. We evaluated PCR-restriction enzyme profiles of internal transcribed spacer 1 (ITS1) that could aid in their identification. Fifty F. hepatica and 30 F. gigantica specimens were collected from different hosts in three provinces of Iran. For DNA extraction, we crushed fragments of the worms between two glass slides as a new method to break down the cells. DNA from the crushed materials was then extracted with a conventional phenol-chloroform method and with the newly developed technique, commercial FTA cards. A primer pair was selected to amplify a 463-bp region of the ITS1 sequence. After sequencing 14 samples and in silico analysis, cutting sites of all known enzymes were predicted and TasI was selected as the enzyme that yielded the most informative profile. Crushing produced enough DNA for PCR amplification with both the phenol-chloroform and commercial FTA card method. The DNA extracted from all samples was successfully amplified and yielded a single sharp band of the expected size. Digestion of PCR products with TasI allowed us to distinguish the two species. In all samples, molecular identification was consistent with morphological identification. Our PCR-restriction enzyme profile is a simple, rapid and reliable method for differentiating F. hepatica and F. gigantica, and can be used for diagnostic and epidemiological purposes. © 2009 Elsevier Inc. All rights reserved

Measurement and Predictors of Resilience Among Community-Dwelling Elderly in Kashan, Iran: A Cross-Sectional Study

Background: As the ability to cope with challenging conditions, resilience results in personal growth and development after experiencing tragic conditions. There are limited studies regarding resilience and its associated factors in elderly patients in Iran. Given that the cultural, social, religious characteristics might affect the level of resilience, we conducted the present study among an elderly population in Kashan. Objectives: This study aimed to evaluate the resilience and its associated factors among elderly in Kashan City, Iran. Methods: A cross-sectional study was conducted on 500 individuals who were selected through a two-stage randomized cluster sampling methods among elderly residents of 8 urban health care facilities in Kashan, Iran. Data collection was performed using a five-part instrument including a demographics questionnaire and abbreviated mental test scale, the Connor-Davidson resilience scale, Rosenberg self-esteem scale, and general health questionnaire28. Data were analyzed using descriptive statistics, chi-square test, t-test, analysis of variance and multivariate regression analysis. Results: A significant direct association was found between resilience and the self-esteem scores (r = 0.461, P < 0.001). Conversely, an indirect correlation was found between resilience and mental health scores (r = - 0.510, P < 0.001). Regression analysis showed that self-esteem and mental health could explain 32% of the variance of resilience in older adults. Significant relationships were found between resilience and variables such as age, sex, marital status, income, job, education, and life arrangement (P < 0.05). Conclusions: Several factors including personal characteristics, self-esteem and mental health of the elderly can affect their resilience. Choosing some strategies to modify and improve some of the influencing variables may be effective in increasing the resilience in older adults

Inflammatory myofibroblastic tumor of the larynx: A case report

Introduction: Inflammatory myofibroblastic pseudotumors are initially described in the lung and various extrapulmonary sites such as the orbits, palatine tonsils, ears, gingiva, pterygomaxillary space, and periodontal tissues. These tumors rarely involve the larynx and predilection to the glottis occurs in an indolent manner. Case Report: This case describes a laryngeal myofibroblastic tumor in a 46-year-old woman who presented with an aggressive tumor that extended to the floor of the mouth and the base of the tongue. Extended supraglottic laryngectomy was undertaken for the patient. The diagnosis was spindle cell proliferation with dense lymphoplasma cell infiltration compatible with inflammatory myofibroblastic tumor (Inflammatory pseudotumor or plasma cell granuloma). Definitive diagnosis was achieved with immunohistochemical (IHC) staining. Conclusion: We believe that further IHC studies are required to define the true nature of these tumors especially for those that behave in an aggressive pattern

Genetic and antigenic analysis of type O and A FMD viruses isolated in Iran,

ABSTRACT FMD is one of the most highly contagious diseases of animals, caused by RNA virus belong to Picornaviridae family and Aphtovirus genus. A broad host range and occurrence of FMDV as seven serotypes and also intratypic antigenic variation without clear cut demarcations, which interferes with a concept of sub typing these factors make difficult conditions to diagnosis, control and eradication of disease. Therefore it is very important to characterize virus strains and monitoring the field virus to determine the relationship between field viruses and vaccine strains. The objective of this study was to characterize FMD type O, A, virus isolated from Iran between 2005 and 2006. 13 FMD type A and 6 type O viruses isolated from Iran between 2005 and 2006 were used in this study. All viruses adapted to IBRS2 cells and the clarified infected cell culture supernatants were used for typing by sandwich capture ELISA and extraction of viral RNA for RT-PCR reaction with the specific primer for each type. The PCR products were purified for sequencing. Sequence of 600 nucleotides at the 3` end of 1D gene of all samples subjected to phylogenic analysis and determine the antigenic relationship (&quot;r&quot; Value). All type A viruses that isolated from different province of Iran, sequenced in this study, were closely related to each other and A/iran/05 virus group. The sequencing results of type O isolated from Iran between 2005 and 2006 showed the close genetic relationship between field isolates and the Iranian vaccine strain. The result of average &quot;r&quot; Value detected by two dimensional virus neutralization test, for type A87IR was 0.46 (46%), type A05IR 0.78 (78%), type O Shabestar 0.81 (81%) and type O967 0.90 (90%)