Influence of advanced cylinder coatings on vehicular fuel economy and emissions in piston compression ring conjunction

IC engines contribute to global warming through extensive use of fossil fuel energy and emission of combustion by‐products. Innovative technologies such as cylinder de‐activation (CDA), after‐exhaust heat treatment, surface texturing and coatings are proposed to improve fuel economy and reduce emissions of the vehicle fleet. Therefore, study of coating technology through a comprehensive multi‐physics analytical model of engine top compression ring is important to ascertain ways of promoting energy savings. This paper presents a multi‐scale, multi‐physics model of the compression ring‐cylinder bore conjunction, using three alternative bore surfaces. The model comprises ring dynamics, contact tribology, heat transfer and gas blow‐by. Tribological and thermal properties of advanced coatings, such as Nickel Nanocomposite (NNC) and diamond‐like carbon (DLC) are compared with an uncoated steel bore surface as the base line configuration. Such a comprehensive analysis has not hitherto been reported in open literature, particularly with original contributions made through inclusion of salient properties of alternative bore materials for high performance race engines. Power loss and FMEP are evaluated in a dynamometric test, representative of the World‐ wide harmonised Light vehicles Test Cycle (WLTC). The NNC coating shows promising tribological improvements. The DLC coating is detrimental in terms of frictional power loss and FMEP, although it can effectively improve sealing of the combustion chamber. The differences in power loss of nominated bore surfaces are represented as fuel mass and CO emissions, using theoretical and empirical relations. For the first time the paper shows that advanced coatings can potentially mitigate the adverse environmental impacts of spark ignition (SI) engines, with significant repercussions when applied to the global gasoline‐powered vehicle fleet

Modelling of the Selected Physical Properties of the Fava Bean with Various Moisture Contents UsingFuzzy Logic Design

The current paper indicates the systematic determination of the optimal conditions for the selected physical properties of the fava bean. The effects of varying moisture content of the Barkat fava bean grown in Golestan, Iran, in the range of 9.3-31.3% (Input) on the 15 selected physical properties of the crop, including geometric values as such length; width; thickness; arithmetic and geometric mean diameter; sphericity index surface and the area of the image; gravity and frictional parameters like the weight of 1000 seeds; true density; bulk density; volume and porosity as well as friction (filling and vacating angle stability) as the outputs were predicted. Afterwards, a model relying on fuzzy logic for the prediction of the 15 outputs had been presented. To build the model, training and testing using experimental results from the Barkat fava bean were conducted. The data used as the input of the fuzzy logic model are arranged in a format of one input parameter that covers the percentage of the moisture contents of the beans. In relation to the varying moisture content (input), the outcomes (15 physical parameters) were predicted. The correlation coefficients obtained between the experimental and predicted outputs as well as the Mean Standard Deviation indicated the competence of fuzzy logic design in predicting the selected physical properties of fava bean seeds. Practical ApplicationToday, because of the high demand for crops to be used extensively in the human diet, enhancements in the efficiency of the processing are getting more attention. In this way, finding and/or the determination of the optimal conditions for processing with minimum waste looks very substantial. Therefore, the use of prediction methods in food processing is considered to be a tool for improving the efficiency and the quality of the produced products. In this regard, the fuzzy logic design as a novel prediction tool, along with response surface methodology (RSM) and Artificial Neural Network (ANN), are applied extensively. Therefore Fuzzy Logic Design is optimized to predict the some of the selected physical properties of fava bean, as a function of seed's moisture content. Therefore predicting the behavior of this crop against different moisture contents can improve the quality and performance of the products with the minimum wastes during very short time.(c) 2016 Wiley Periodicals, Incinfo:eu-repo/semantics/publishedVersio

A transient tribodynamic approach for the calculation of internal combustion engine piston slap noise

An analytical/numerical methodology is presented to calculate the radiated noise due to internal combustion engine piston impacts on the cylinder liner through a film of lubricant. Both quasi-static and transient dynamic analyses coupled with impact elasto-hydrodynamics are reported. The local impact impedance is calculated, as well as the transferred energy onto the cylinder liner. The simulations are verified against experimental results for different engine operating conditions and for noise levels calculated in the vicinity of the engine block. Continuous wavelet signal processing is performed to identify the occurrence of piston slap noise events and their spectral content, showing good conformance between the predictions and experimentally acquired signals

Oil Control Ring Friction And Low Viscosity Lubricants: A Combined Numerical and Experimental Analysis

A common strategy to reduce engine parasitic power losses is to decrease pumping and viscous friction losses through use of a low viscosity engine oil. However, reducing lubricant viscosity can also decrease the contact load carrying capacity, thus exacerbating direct interaction of contacting surfaces. This leads to boundary frictional losses in contacts prone to mixed regime lubrication. As a result, detailed experimental and modelling studies of engine component frictional behaviour is required to ensure the engine level trade-offs. This paper presents a combined experimental and numerical investigation of frictional behaviour of three-piece piston oil control rings. A bespoke tribometer replicates kinematics of the contact between a full oil control ring and the cylinder liner. The three-piece oil control ring is composed of two segments, separated by a waveform type expander. The experimental results indicate the dominance of mixed regime of lubrication throughout the stroke. This is particularly the case when the experiments are conducted at 80 °C; a typical engine sump temperature, when compared with the case of 20 °C (a typical engine start-up temperature in the UK in the Spring). A mixed hydrodynamic numerical model of the oil control ring-cylinder liner tribological interface is employed to apportion frictional contributions with their physical underlying mechanisms. The combined experimental-predictive approach provides key information for engine designers when considering the efficiency trade-offs

Implantation phaeohyphomycosis caused by a non-sporulating Chaetomium species

We report the case of a 66-year-old Iranian woman with a phaeohyphomycotic cyst (approximately 3 × 2.5 cm in size) on the right lateral side of the neck. She had dysphagia and hoarseness, without any pain. She complained about discharge of black liquid on the skin and irritation. Histological examination of biopsy fragments from the lesions showed septate, branched brown hyphae. The fungus was cultured, but sporulation remained absent from 4- week-old cultures on Sabouraud dextrose agar (SDA), malt extract agar (MEA), potato dextrose agar (PDA), and water agar with sterile filter paper. Identification with the genus Chaetomium was achieved by sequencing the internal transcribed spacer (ITS) and the small subunit (SSU) domains of the rDNA gene and comparison with sequences held at GenBank and at the Centraalbureau voor Schimmelcultures (CBS). Sequencing of the SSU rRNA gene reveals this strain as belonging to the genus Chaetomium. The sequence of ITS did not fully match with any sequence of available ex-type strains of Chaetomium, Thielavia, Madurella and Papulaspora and hence might belong to an undescribed species. However, without diagnostic morphological features the taxon cannot be introduced as a novel member of the genus Chaetomium. After local excision of the cyst and antifungal therapy with ketoconazole (200. mg twice a day), the lesion regressed and healed completely. © 2013 Elsevier Masson SAS

NRAMP1 gene polymorphisms and cutaneous leishmaniasis: An evaluation on host susceptibility and treatment outcome

Background & objectives: Association between polymorphisms in the natural resistance associated macrophage protein 1 (NRAMP1) gene and susceptibility to cutaneous leishmaniasis (CL) has been demonstrated worldwide; however, the reported results were inconsistent. This study aimed to determine the association of NRAMP1 variants with susceptibility to CL infection and patients� response to treatment in Isfahan province of Iran. Methods: Peripheral blood samples were collected from 150 patients with CL and 136 healthy controls. The CL patients were treated with intralesional injection of meglumine antimoniate. The polymorphic variants at NRAMP1 (A318V and D543N) were analyzed using PCR-RFLP. The chi-square test and Fisher�s exact test were used to compare frequencies of alleles and genotypes of polymorphisms between patient and healthy control populations. Results: There was a statistically significant difference in the D543N (rs17235409) polymorphism between the CL patients and healthy controls (p=0.008). However, no significant association was detected for A318V (rs201565523) polymorphism between groups (p=0.26). In addition, there was a lack of association between D543N and A318V genotypes with response to treatment (p=0.54 and p=0.31, respectively). Interpretation & conclusion: The results indicated that genetic variations of D543N (rs17235409) might be associated with susceptibility to CL infection. These data may be used for detection of sensitive individuals and prevention of CL in endemic areas. © 2016, Malaria Research Center. All rights reserved

Controlling interferometric properties of nanoporous anodic aluminium oxide

A study of reflective interference spectroscopy [RIfS] properties of nanoporous anodic aluminium oxide [AAO] with the aim to develop a reliable substrate for label-free optical biosensing is presented. The influence of structural parameters of AAO including pore diameters, inter-pore distance, pore length, and surface modification by deposition of Au, Ag, Cr, Pt, Ni, and TiO2 on the RIfS signal (Fabry-Perot fringe) was explored. AAO with controlled pore dimensions was prepared by electrochemical anodization of aluminium using 0.3 M oxalic acid at different voltages (30 to 70 V) and anodization times (10 to 60 min). Results show the strong influence of pore structures and surface modifications on the interference signal and indicate the importance of optimisation of AAO pore structures for RIfS sensing. The pore length/pore diameter aspect ratio of AAO was identified as a suitable parameter to tune interferometric properties of AAO. Finally, the application of AAO with optimised pore structures for sensing of a surface binding reaction of alkanethiols (mercaptoundecanoic acid) on gold surface is demonstrated