Effect of ethanol on the performance,emission and combustion characteristics of a compression ignition engine fuelled with vegetable oil–diesel blend

Experimental work had been carried out to analyse the effect of ethanol on the performance, emission and combustion characteristic of vegetable oil–diesel blend (50% vol. rapeseed oil and 50% vol. diesel fuel). The vegetable oil–diesel–ethanol blended fuels were prepared by using microemulsification technique and the main properties were measured. The results showed that, with the increase in ethanol volume fraction in the blends, the viscosity and density were decreased and close to those of diesel fuel. The combustion started later; the peak cylinder pressure, peak heat release rate varied significantly under different operating conditions and the corresponding crank angles of the peak values were retarded. There were slightly higher brake-specific fuel consumptions. Smoke and nitrogen oxide emissions were observed to reduce, but carbon monoxide and hydrocarbon emissions were found slightly higher with the increase of ethanol volume fraction under all ranges of engine operating conditions.     

Optimisation of performance and emission characteristics of CI engine fuelled with Mahua oil methyl ester–diesel blend using response surface methodology

ABSTRACT

The aim of present study is to optimise the performance and emission characteristics of compression ignition engine fuelled with biodiesel blended diesel fuel using response surface methodology (RSM). During engine trials, two parameters, viz. blend ratio and load torque, were varied and the responses like brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), carbon monoxide (CO), hydrocarbon (HC), nitrogen oxides (NOx) and smoke opacity were investigated. Statistical tool like RSM was used to design experiments. Optimisation of parameters was performed using the desirability approach of RSM for superior performance and lower emission. The results revealed that at optimal input parameters (40% fuel blend and 15?Nm load torque), the values of performance and emission parameters in optimal solutions: BSFC (kg/kWh): 0.2252, BTE (%): 29.2885, CO (vol. %): 0.00757, HC (ppm): 5.7195, NO_x (ppm): 319.78, smoke (vol. %): 4.50 were found for the Mahua oil methyl esters blended with diesel.     

Prediction of engine performance and exhaust emissions with different proportions of ethanol–gasoline blends using artificial neural networks

The main purpose of this study is to experimentally investigate the use of ANNs (artificial neural networks) modelling to predict engine power, torque and exhaust emissions of a spark ignition engine which operates with gasoline and methanol blends. For the ANN modelling, the standard back-propagation algorithm was found to be the optimal choice for training the model. Afterwards, the performance of the ANN predictions was evaluated with the experimental results by comparing the predictions. Fuel type and engine speed have been used as the input layer, while engine torque, power, exhaust emissions, Tex and BSFC have also been used separately as the output layer. It was found that the ANN model is able to predict the engine performance, exhaust emissions, Tex and BSFC with a correlation coefficient of 0.9991887425, 0.9990868573, 0.9986749623, 0.9988624137, 0.9976761492, 0.9992943894 and 0.9978899033 for the Power, Torque, CO, CO₂, HC, Tex and BSFC for testing data, respectively.     

Performance,emission and combustion characteristics of a single cylinder spark ignition engine using ethanol–petrol-blended fuels

The performance, exhaust emission and combustion analyses of a single cylinder spark ignition engine fuelled with extended range of ethanol–petrol blends were carried out successfully at full load conditions. Ethanol produced from raffia trunks was blended with petrol at different proportions by volume. In order to establish a baseline for comparison, the engine was first run on neat petrol. The engine performance parameters (engine torque, brake power, brake specific fuel consumption, brake mean effective pressure and brake thermal efficiency), exhaust emission parameters (CO, HC, CO₂ and O₂ emissions) and combustion parameters were determined for each blend of fuel at different engine speeds. The test results interestingly revealed that the addition of ethanol to petrol causes an improvement in combustion characteristics and significant reduction in exhaust emissions which in turn improved engine performance. In all, ethanol and its blends with petrol exhibited performance characteristics trends similar to that of petrol thus confirming them as suitable alternative fuels for spark ignition engines.     

The effect of temperature on the emission of formaldehyde and volatile organic compounds (VOCs) from laminate flooring — case study

The effect of temperatures of 23, 29, 50°C on formaldehyde and volatile organic compounds (VOCs) emission from laminate flooring Type A (with particleboard as substrate) and Type B (with high density fibre (HDF)) was examined. At 23 and 29°C the measurements did not show any emissions of formaldehyde and very low emissions of VOCs. At a temperature of 50°C, Type A showed a high initial emission of formaldehyde and VOCs, which decreased with time. The emission from Type B was much lower. In conclusion, some laminate flooring may affect the chemical contamination of indoor air with the use of floor heating.     

Investigation on a diesel engine’s performance with integration of magnetic flux on the fuel line

Application of magnetic flux (MF) on the fuel line of diesel engines is a promising technique to enhance the performance of the engine. In this work, MF was applied by placing neodymium magnet pairs (MP) on the fuel line of a diesel engine test setup. Tests were carried out for different loads in the range of 0–8?kg. In the first stage, performance of the test setup was evaluated without MF for fixed load condition; in the second stage, performance evaluation was done by increasing number of MP on the fuel line – that is, the number of magnetic pairs was increased from 1 to 4. The experimental results confirmed that fuel consumption rate decreases with an increase in magnetic pair from 1 to 3; after employing the fourth magnetic pair, an increase in fuel consumption rate was observed. This clearly gives an idea for the presence of critical magnetic field for fuel savings.     

Thermal characteristics of externally venting flames and their effect on the exposed façade surface

In a compartment fire, Externally Venting Flames (EVF) may significantly increase the risk of fire spreading to adjacent floors or buildings, especially when combustible insulation materials are installed on the building façade. An increasing number of recent reports suggest that existing fire engineering design methodologies cannot describe with sufficient accuracy the characteristics of EVF under realistic fire load conditions. In this context, a series of fire safety engineering design correlations used to describe the main EVF thermal characteristics, namely EVF centreline temperature and EVF-induced heat flux on the exposed façade surface, are comparatively assessed. Towards this end, measurements obtained in a medium- and a large-scale compartment-façade fire test are employed; aiming to broaden the scope of the validation study, predictions of the investigated correlations are further compared to measurements obtained in 6 large-scale fire tests found in the literature. It is found that the correlation proposed in EN1991-1–2 (Eurocode 1) for the estimation of the EVF centreline temperature is under-predicting the measured values in large-scale fire tests. In addition, it is concluded that estimation of the local flame emissivity should take into account the specific fuel type used in each case.     

Process performance of anaerobic co-digestion of raw and acidified pig slurry

The effect of incorporating different ratios of acidified pig slurry on methane yield was evaluated in two scales of anaerobic digesters: Thermophilic (50 °C) pilot scale digester (120 l), operating with an average hydraulic retention time of 20 days and thermophilic (52 °C) full-scale digesters (10 and 30 m³), operating with an average hydraulic retention time of 30 days. In the lab-scale digester, different inclusion levels of acidified slurry (0-60%) were tested each 15 days, to determine the maximum ratio of acidified to non-acidified slurry causing inhibition and to find process state indicators helping to prevent process failure. In the full-scale digesters, the level of inclusion of the acidified slurry was chosen from the ratio causing methane inhibition in the pilot scale experiment and was carried on in a long-term process of 100 days. The optimal inclusion level of acidified pig slurry in anaerobic co-digestion with conventional slurry was 10%, which promoted anaerobic methane yield by nearly 20%. Higher inclusion levels caused methane inhibition and volatile fatty acids accumulations in both experiments. In order to prevent process failure, the most important traits to monitor in the anaerobic digestion of acidified pig slurry were found to be: sulfate content of the slurry, alkalinity parameters (especially partial alkalinity and the ratio of alkalinity) and total volatile fatty acids (especially acetic and butyric acids).     

A parametric study on the effects of displacer-cylinder-circumferential-wall thermal conditions on the performance of a γ-type LTD Stirling engine

ABSTRACT

Regarding a Stirling engine’s heat source and heat sink, most of the studies in the literature focus only on the magnitude of temperature difference between them. However, different Stirling engines adopt very different heat-source and heat-sink configurations. This study is aimed at understanding the effects of different displacer-cylinder-wall thermal conditions on engine performance using computational fluid dynamics (CFD). Results include p–V diagrams, heat flux distributions, temperature variations, and effects of three displacer-cylinder-wall parameters on indicated power and efficiency. It is found that the thermal conditions on the displacer-cylinder-circumferential wall (DCCW) impose significant effects on engine performance. Within the ranges of parameters investigated in this study, extending the coverage of heat source and heat sink on this wall improves up to 28% in indicated power at the cost of losing about 10% in efficiency, proving the significance of DCCW conditions on engine performance.     

The effect of client and type and size of construction work on a contractor’s bidding strategy

This paper offers a bidding strategy model for use by contractors as part of a more informed approach in selecting which contracts to bid for, and as a basis for determining the most appropriate mark-up level for various types and sizes of construction work and client types. Regression analysis is used in measuring a contractor’s competitiveness between bids (by using the lowest bid/own bid ratio) and within bids (by using the lowest bid/cost estimate ratio) according to type and size of construction work and client type. The model was tested on a large and reputable Hong Kong contractor. This particular contractor’s bidding behaviour was found to be largely unaffected by the type of construction work, but significantly affected by the client type and the size of the construction work. Three quadratic models (regressing lowest bid/cost estimate on the size of the construction work) are also successfully developed for projects from the private sector, the Hong Kong Government and the Hong Kong Housing Authority, respectively.     

Effect of performance parameters on the pneumatic conveying solid–gas heat transfer

The waste heat recovery unit is becoming a mandatory and integral part of modern-day heat interacting devices, through regeneration waste heat energy is recovered within the plant which increases the overall thermal efficiency. In the present work, investigation is made on one such heat recovery system, where we used the interaction of solid–gas in cyclone separators connecting the tube. The experimental set-up of 60?mm diameter and 3 m height was used and made with iron. The effect of flow parameters such as feed rate, velocity and the geometrical features such as height and particle size variations were studied, and found that the heat transfer rate and thermal effectiveness increase with velocity and reduce further, hence the optimum velocity needs to be maintained for maximum effectiveness since the thermal effectiveness variation of solid and air is opposite to each other.     

Impact of pre‐construction planning and project characteristics on performance in the US electrical construction industry

The mild recession experienced in the early part of this decade forced many US electrical contractors to reduce their profit margins as a way to win jobs and survive economically. However, to make up for lower profit margins, contractors turned to ‘better planning’ as a method for improving their efficiency and increasing their profitability. In general, contractors believe that better planning contributes to better project performance, but the evidence has been mostly anecdotal. A study was conducted recently that transformed anecdotal evidence about the impact of pre‐construction planning on performance into quantitative evidence. The research resulted in the development of a model pre‐construction planning process that was based on outstanding projects that were well planned and performed well. The study quantified the relationship between pre‐construction planning activities, project characteristics and performance, and a separate validation study found that those projects that performed a comprehensive planning process similar to the model planning process were more likely to achieve their estimated work hours, profit, budget and completion goals.     

Mixture design concept and mechanical characteristics of PS ash–cement-treated clay based on the water absorption and retention performance of PS ash

In an attempt to reduce environmental impact, paper sludge ash (PS ash) has recently been studied for its complementary reuse with cement for soil stabilization. In order to establish the optimal mixture design for combining PS ash and cement in soils, a detailed investigation into the stabilizing mechanism is required. To assess the combined effects of PS ash and cement on the strength development of stabilized clay soil, referred to as PS ash–cement-treated clay, a new critical parameter, the unabsorbed and unretained clay-water/cement ratio W*/C, was proposed. To determine W*/C, a new testing method for evaluating the water absorption and retention performance of PS ash was developed. It was revealed that the water absorption and retention rate W_ab of PS ash increased with curing time. Unconfined compression tests conducted on the PS ash–cement-treated clay with various water-cement–PS ash mixture proportions and different curing times affirmed that the strength development was fundamentally governed by the parameter W*/C. This suggests that the water absorption and retention rate W_ab obtained by the developed method is an essential material parameter in the mixture design for the PS ash–cement-treated clay. It was also found that the effect of the hybrid treatment method, which uses both cement and PS ash, was better than that of the method which uses cement alone, particularly under high W*/C conditions. This indicates that the water absorption and retention performance of PS ash can be fully utilized when the mixture has sufficient unabsorbed and unretained water for cement hydration.     

The effect of optical anisotropies on building glass fa?ades and its measurement methods

Commonly, in the evaluation of the optical appearance of glass panes in building envelopes, anisotropies are a reason for a dispute between the architect or client and the fa?ade manufacturer. Sometimes each party has a different perception, how strong the anisotropies are and what is permissible. This paper discusses in the first part the formation of the anisotropies and their natural sources. It is shown that the appearance of this phenomenon is dependent on the environmental conditions of the building site as well as the glass quality. If the application of thermally tempered glass cannot be avoided, the quality assurance of the production process has to be carefully planned. Furthermore a method for the quantitative measurement of anisotropies is proposed and prescribed in detail. This method can assist in the quality assurance process. Measurements are showing that probably the best tempered glass offers slight anisotropies and that under unfavorable conditions these anisotropies can become evident.     

Influence of vertical loads on lateral response of pile foundations in sands and clays

Although the load applied to pile foundations is usually a combination of vertical and lateral components, there have been few investigations on the behavior of piles subjected to combined loadings. Those few studies led to inconsistent results with regard to the effects of vertical loads on the lateral response of piles. A series of three-dimensional (3D) finite differences analyses is conducted to evaluate the influence of vertical loads on the lateral performance of pile foundations. Three idealized sandy and clayey soil profiles are considered: a homogeneous soil layer, a layer with modulus proportional to depth, and two-layered strata. The pile material is modeled as linearly elastic, while the soil is idealized using the Mohr–Coulomb constitutive model with a non-associated flow rule. In order to confirm the findings of this study, soils in some cases are further modeled using more sophisticated models (i.e. CYsoil model for sandy soils and modified Cam-Clay (MCC) model for clayey soils). Numerical results showed that the lateral resistance of the piles does not appear to vary considerably with the vertical load in sandy soil especially at the loosest state. However, the presence of a vertical load on a pile embedded in homogeneous or inhomogeneous clay is detrimental to its lateral capacity, and it is unconservative to design piles in clays assuming that there is no interaction between vertical and lateral loads. Moreover, the current results indicate that the effect of vertical loads on the lateral response of piles embedded in two-layered strata depends on the characteristics of soil not only surrounding the piles but also located beneath their tips.     

No time for crime? The effect of compulsory engagement on youth crime

This paper examines the potential incapacitation effect on various categories of crime committed by young persons. I exploit the increase in compulsory education-work participation age from 15 to 17 in Australia's largest state. The policy primarily increased participation in schools with high enrolments in school-based vocational education programs. By using incidents of crime, I incorporate incapacitation effects on crimes that do not lead to arrests and provide net effect of the policy. Results show substantial reduction in incidents of crime, particularly by male offenders in urban areas and suggest that the policy did not displace crime from streets to schools. Crimes against property, which are often diverted from the criminal justice system, show the largest decline.     

The relation between the intelligibility of irrelevant speech and cognitive performance—A revised model based on laboratory studies

Irrelevant background speech causes dissatisfaction and impairs cognitive performance in open-plan offices. The model of Hongisto (2005, Indoor Air, 15, 458-468) predicts the relation between cognitive performance and the intelligibility of speech described with an objectively measured quantity, the Speech Transmission Index (STI). The model has impacted research in psychology and room acoustics as well as the acoustic design guidelines of offices. However, the model was based on scarce empirical data. The aim of this study was to revise the model based on a systematic literature review, focusing on laboratory experiments manipulating the STI of speech by wide-band steady-state noise. Fourteen studies reporting altogether 34 tests of the STI-performance relation were included. According to Model 1 that includes all tests, performance begins to decrease approximately above STI = 0.21 while the maximum decrease is reached at STI = 0.44. Verbal short-term memory tasks were most strongly and very consistently affected by the STI of speech. The model for these tasks showed a deterioration in performance between STI 0.12 and 0.51. Some evidence of an STI-performance relation was found in verbal working memory tasks and limited evidence in complex verbal tasks. Further research is warranted, particularly concerning task-specific effects.     

Impact of partially stabilised zirconia on a single-cylinder diesel engine’s performance,using orange oil methyl ester biodiesel

Exhaustion of crude oil resources, rise in fuel prices and necessity to find less-carbon fuel have encouraged to find an alternative fuel. Biodiesel is characterised by its fuel properties, which may have an adverse effect on performance and emission characteristics of the engine. Thus, it is necessary to trans-esterify the extracted orange oil and make it viable for diesel engine. In the present work, partially stabilised zirconia was used as a thermal barrier coating (TBC) for the combustion chamber components using plasma spray technique. The present study focused on the impact of TBC on performance and emission characteristics of a diesel engine with B1 (20% orange oil methyl ester with 80% diesel) sample and diesel. Increased brake thermal efficiency and reduced brake-specific fuel consumption are observed for B1 in the TBC engine. On comparing with the uncoated engine, the B1 in coated engine exhibited lower carbon monoxide, hydrocarbon, oxides of nitrogen and smoke emissions than diesel.     

Computational evaluation of building physics—The effect of building form and settled area,microclimate on pedestrian level comfort around buildings

Wind discomfort and the dangers that the wind may lead can be harmful in terms of comfort conditions of both indoor and outdoor environment of the building/buildings to be constructed or just completed. The wind effects on a site can be divided in two as: mechanical wind effects and thermal wind effects. This study is specifically about mechanical wind stress and pedestrian wind comfort. Typically, the cause of frequent occurrences of strong wind at pedestrian area is primary related to the configuration of building structures and/or topography in the vicinity of the pedestrian area. Depending on the characteristics of the wind including magnitude, uniformity, ambient temperature, etc., the level of disturbance to users of pedestrian areas can be different. In this context, the regions where Necmettin Erbakan University (N.E.U.) temporary education buildings are located have a fairly intensive topography in terms of wind. Therefore, detailed analyses of the inside regions and the surrounding areas of education buildings in particular are performed in terms of microclimatic comfort and indoor energy recovery. Especially, the topography where the university campus temporary educational buildings are located has very high wind climate conditions comparing to the city of Konya, Turkey, climate conditions. In this study pedestrian level wind conditions around N.E.U. campus buildings and in urban areas and campus buildings settlements topography are analyzed by CFD FloEFD. The aim of the study is to analyze causes of wind nuisance in campus site area and around temporary education buildings, and compare and evaluate remedial measures. The results show that current campus settlement, around the buildings and amphi classes are seen to reach very discomforting levels in terms of in classroom comfort. Draft architectural campus temporary education buildings projects proposed by the author can improve on existing wind conditions where possible, and as a minimum, can not significantly degrade wind conditions especially when considering the safety criteria.