Showing papers in "World Journal of Engineering in 2017"

On firefly algorithm: optimization and application in mobile robot navigation

Abstract: Purpose This paper aims to propose an optimized overview of firefly algorithm (FA) over physical-natural impression of fireflies and its application in mobile robot navigation under the natural intelligence mechanism. Design/methodology/approach The brightness and luminosity are the decision variables in proposed study. The paper achieves the two major goals of robot navigation; first, the optimum path generation and, second, as an obstacle avoidance by co-in-centric sphere-based geometrical technique. This technique comprises the optimum path decision to objective function and constraints to paths and obstacles as the function of algebraic-geometry co-relation. Co-in-centric sphere is the proposed technique to correlate the constraints. Findings It is found that the present FA based on concentric sphere is suitable for efficient navigation of mobile robots at the level of optimum significance when compared with other approaches. Originality/value The paper introduces a novel approach to implement the FA for unknown and uncertain environment.

Coconut fibre-reinforced cement-stabilized rammed earth blocks

Abstract: Purpose This study aims to investigate the optimum proportion of coconut fibre and cement suitable for rammed earth wall construction. Coconut fibres and cement can be easily incorporated into the soil mixture which adds strength and durability to the wall. This paper highlights the salient observations from a systematic investigation on the effect of coconut fibre on the performance of stabilized rammed earth blocks. Design/methodology/approach Stabilization of soil was done by adding Ordinary Portland Cement (2.5, 5.0, 7.5 and 10.0 per cent by weight of soil), whereas coconut fibre in length about 15 mm was added (0.2, 0.4, 0.6, 0.8 and 1.0 per cent by weight of soil) as reinforcement. Thirty types of mixes were created by adding different proportions of cement and fibre to locally available soil and compacting the mix at constant compaction energy in three layers with Proctor rammer. Findings Samples were tested for compressive strength and tensile strength, and failure patterns were analysed. The use of cement and fibre increases ultimate strengths significantly up to an optimum limit of 0.8 per cent fibre content, provides a secondary benefit of keeping material bound together after failure and increases residual strength. Benefits of fibre reinforcement includes both improved ductility in comparison with raw blocks and inhibition of crack propagation after its initial formation. Originality/value After analysing the results, it is recommended to use 0.8 per cent fibre and 5-10 per cent cement by weight of soil to achieve considerable strength. This research may add a value in the areas of green and sustainable housing, waste utilization, etc.

Thermodynamic analysis of hybrid nanofluid based solar flat plate collector

Abstract: Purpose This paper aims to present an analytical investigation of energy and exergy performance on a solar flat plate collector (SFPC) with Cu-CuO/water hybrid nanofluid, Cu/water and CuO/water nanofluids as collector running fluids. Design/methodology/approach Heat transfer characteristics, pressure drop and energy and exergy efficiencies of SFPC working on these nanofluids are investigated and compared. In this study, a comparison is made by varying the mass flow rates and nanoparticle volume concentration. Thermophysical properties of hybrid nanofluids are estimated using distinctive correlations available in the open literature. Then, the influence of these properties on energy and exergy efficiencies of SFPC is discussed in detail. Findings Energy analysis reveals that by introducing the hybrid nanoparticles in water, the thermal conductivity of the working fluid is enhanced by 17.52 per cent and that of the individual constituents is enhanced by 15.72 and 15.35 per cent for Cu/water and CuO/water nanofluids, respectively. This resulted in 2.16 per cent improvement in useful heat gain for hybrid nanofluid and 1.03 and 0.91 per cent improvement in heat gain for Cu/water and CuO/water nanofluids, respectively. In line with the above, the collector efficiency increased by 2.175 per cent for the hybrid nanofluid and 0.93 and 1.05 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Exergy analysis elucidates that by using the hybrid nanofluid, exergy efficiency is increased by 2.59 per cent, whereas it is 2.32 and 2.18 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Entropy generation is reduced by 3.31, 2.35 and 2.96 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, as compared to water. Research limitations/implications However, this is associated with a penalty of increment in pressure drop of 2.92, 3.09 and 2.74 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, compared with water. Originality/value It is clear from the analysis that Cu-CuO/water hybrid nanofluids possess notable increment in both energy and exergy efficiencies to use them in SFPCs.

Removal of Cr(VI) from aqueous solutions by using activated carbon supported iron catalysts as efficient adsorbents

Abstract: Purpose The purpose of this paper is to focus on the removal of hexavalent chromium [Cr(VI)] from wastewater by using activated carbon-supported Fe catalysts derived from walnut shell prepared using a wetness impregnation process. The different conditions of preparation such as impregnation rate and calcination conditions (temperature and time) were optimized to determine their effects on the catalyst’s characteristics. Design/methodology/approach The catalyst samples were characterized using thermogravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption of Cr(VI) by using using activated carbon supported Fe catalysts derived from walnut shell as an adsorbent and catalyst was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose, solution pH and initial concentrations. Findings Results showed that higher adsorption capacity and rapid kinetics were obtained when the activated walnut shell was impregnated with Fe at 5 per cent and calcined under N2 flow at 400°C for 2 h. The adsorption isotherms data were analyzed with Langmuir and Freundlich models. The better fit is obtained with the Langmuir model with a maximum adsorption capacity of 29.67 mg/g for Cr(VI) on Fe5-AWS at pH 2.0. Originality/value A comparison of two kinetic models shows that the adsorption isotherms system is better described by the pseudo-first-order kinetic model.

Influence of an inclined magnetic field on heat and mass transfer of the peristaltic flow of a couple stress fluid in an inclined channel

Abstract: Purpose This paper aims to intend for investigating the influence of an inclined magnetic field on the peristaltic flow of a couple stress fluid through an inclined channel with heat and mass transfer. Design/methodology/approach Long wavelength and low Reynolds number methodology is actualized for simplifying the highly nonlinear equations. Mathematical expressions of axial velocity, pressure gradient and volume flow rate are obtained. Pressure rise, frictional force and pumping phenomenon are portrayed and symbolized graphically. Exact and numerical solutions have been carried out. The computed results are presented graphically for various embedded parameters. Temperature and concentration profile are also scrutinized and sketched. Findings Results from the current study concluded that the fluid motion can be enhanced by increasing the inclination of both the magnetic field and the channel. Originality/value The elemental characteristics of this analysis is a complete interpretation of the influence of couple stress parameter and inclination of magnetic field on the velocity, pressure gradient, pressure rise and frictional forces.

A robust cascaded controller for DC-DC Boost and Cuk converters

Abstract: Purpose This paper aims to propose a robust cascaded controller based on proportional-integral (PI) and continuous sliding mode control. Design/methodology/approach Cascaded control structure is an attractive control scheme for DC-DC power converters. It has a two-loop structure where the outer loop contains PI controller and the inner loop uses sliding mode control (SMC). This structure thus combines the merits of both the control schemes. However, there are some issues that have prohibited its adoption in industry, the discontinuous nature of SMC which leads to variable switching frequency operation and is hard to realize practically. This paper attempts to overcome this issue by changing the discontinuous functionality of SMC to continuous by utilizing the concept of equivalent control. Findings The robustness of the controller designed is verified by considering various cases, namely, ideal case with no uncertainties, sudden variation of input supply voltage, load resistance, reference voltage, circuit-parameters and for noise disturbance. The controller effectiveness is validated by simulating the DC-DC boost and Cuk converters in SimPowerSystems toolbox of MATLAB/Simulink. It is shown that the performance of the proposed controller is satisfactory, and both reference output voltage and inductor current are tracked with little or no sensitivity to disturbances. Originality/value The results for various scenarios are interesting and show that the controller works quite satisfactorily for all the simulated uncertainties.

A review of using porous asphalt pavement as an alternative to conventional pavement in stormwater treatment

Abstract: Purpose Porous asphalt has been used for than 50 years, but it was originally developed in 1970 at Franklin institute in Philadelphia, Pennsylvania. By 1974 the first formalized procedure was created by the federal highway administration to design mixtures. Many researches on porous asphalt mixture have been conducted for the past two decades. However, there remains some concern about the potential adverse impacts of infiltrated surface water on the underlying groundwater. The purpose of this paper is to presents a short review on the application of porous asphalt pavement stormwater treatment. Design/methodology/approach In this paper, a critical review on history and benefits is presented followed by review of general studies of using porous asphalt pavement, and some recent scientific studies that examine potential contamination of soil and groundwater because of infiltration systems. Findings This paper indicates that porous asphalt pavement is more efficient than conventional pavements in terms of retaining pollutants, improving the quality of water and runoff while maintaining infiltration. Originality/value This paper may also help reduce land consumption by reducing the need for traditional storm-water management structures. However, on the other hand, the priority objectives which is minimizing increased flooding and pollution risks while increasing performance efficiency and enhancing local environmental quality-of-life is achieved.

Fuel production, performance, and emission of a CI engine using waste plastics oil

Abstract: Purpose This paper aims to present the production of waste plastic oil from landfill waste plastics, the performance and emissions of a compression ignition (CI) engine, using waste plastic oil, were tested and compared with using diesel oil. The physical characteristics, gross calorific value (MJ/kg), kinematic viscosity cst @40°C, specific gravity @15.6°C, cetane index, flash point and distillation temperature @90 per cent are determined. The experimental CI engine is a four-stroke, direct injection, single cylinder, 709 C.C. and has been tested with in-brake-specific fuel consumption (BSFC), brake conversion efficiency, brake-specific energy consumption and exhaust gas emissions. Design/methodology/approach The results show that the characteristics of liquid fuel from landfill plastics (LFLP3) are similar to diesel oil. The CI engine was able to run with LFLP3. The efficiency was slightly higher than that of diesel fuel, whereas the BSFC was lower. The exhaust-gas emission average for LFLP3 was reduced compared to diesel oil operation. Findings The efficiency of the CI engine using LFLP3 is slightly higher than diesel fuel at all load conditions. In this study, LFLP3 was a lower pollutant than diesel fuel. Environmental values and energy consumption are important when reviewing the ignition of any fuel in a combustion chamber. Originality/value The efficiency of the CI engine using LFLP3 is slightly higher than diesel fuel at all load conditions. In this study, LFLP3 was a lower pollutant than diesel fuel. Environmental values and energy consumption are important when reviewing the ignition of any fuel in a combustion chamber.

Effect of γ (gamma)-radiation on mechanical properties of raw and polyethylene glycol-modified bleached jute reinforced polyester composite

Abstract: Purpose This paper aim to comparatively study of mechanical properties of gamma radiation treated raw and polyethylene glycol modified bleached jute reinforced polyester composite. The natural fiber-reinforced composite has been a wide area of research, and it is the preferred choice due to its superior physical and mechanical properties like low density, stiffness and light weight. Among several natural fibers, jute is one that has good potential as reinforcement in polymer composite. Jute fibers biodegradability, low cost and moderate mechanical properties make it as a preferable reinforcement material in the development of polymer matrix composites. Design/methodology/approach In the present work, raw jute fabrics-reinforced polyester composite (as RJPC) and polyethylene glycol (PEG)-modified bleached jute fabrics-reinforced polyester composite (as MBJPC) were fabricated by the heat-press molding technique at 120°C for 5 min at a pressure of 5 tons. Prior to the composite formulation, low lignin content bleached jute fabrics were chemically modified with PEG for the better compatibility of the fabrics with the polyester matrix and enhancing elongation properties. All the composites irradiated with different gamma radiation dose in the range of 2 to 14 kGy. Findings The irradiated composites showed highest improved of mechanical properties at the 10 kGy γ-radiation dose. However, the hard and sunlight-sensitive high lignin content γ-RJPC showed higher mechanical properties except elongation properties compared to that of low lignin content γ-MBJPC. Originality/value After the γ-ray irradiation, both the γ-RJPC and γ-MBJPC developed high degree of cross-linking among the polyester molecules and thereto fabrics with the consequence of significant changed of surface morphology as observed by atomic force microscopy.

CO2 emission during the combustion of Orhaneli lignite coal

Abstract: Purpose In Turkey, dependence on foreign countries for energy is a problem which upsets all economic balances. Turkey’s biggest fossil energy source is lignite coal. Therefore, energy conversion of lignite in thermal plants, causing minimum environmental effect is extremely important. The basic problem in terms of the combustion technology is to improve the combustion technology that can burn the low-qualified fuels that do not have standard fuel features (lignite, peat, schist). The most suitable technology today for the efficient and clean combustion of nonstandard low-qualified fuels is the combustion at fluidized-bed technology. In this study, CO2 emission that occurs during the combustion of Orhaneli coal that is one of our native low-qualified lignite, has been investigated according to the experimental study. Design/methodology/approach For this combustion experiment, laboratory-scaled circulating fluidized-bed (CFB) process that exists at TUBITAK-MAM Energy Institute which has been designed and used before has been used. The effect of excess-air coefficient, combustion type and bed temperature to the greenhouse gas formation and CO2 emission has been investigated experimentally. In terms of flue gas emissions, it has been detected that the decrease of the amount of CO2 that has occurred has no positive effects on combustion efficiency, water vapor, SO2, NOx, CO and other gases which occur during deficient combustion must be thought as a whole and each reaction affects each other similar to complex reactions. Findings As a consequence of measuring CO2 emissions over 10 minute periods, CO2 emissions are 12.43 percent average, CO2 decreases at different air coefficient values; Often form undesirable side reactions such as CO, NOx with back and forth reactions. Originality/value The importance of aerodynamic structure of the system, and the losses and leakages forming in the system has been observed experimental and affected parameters are evaluated.

Reprocessing and environmental desulphurization of sulphide mining waste from sphalerite flotation: case of Chaabet El Hamra mine, Algeria

Abstract: Purpose Tailings generated by sulphide ore processing at Chaabet El Hamra mine contain a variety of sulphide minerals such as pyrite, marcasite, sphalerite, galena and chalcopyrite with carbonated and siliceous gangue. It is well known that the presence of pyrite can cause environmental threats, in particular the acid mine drainage risk (AMD), if there is not enough neutralizing potential. Waste chemical analyses show that the content of total sulphur (S) is more than 9 per cent, which could be possible to separate the pyrite from other heavy minerals based on interfacial property of these minerals, because the pyrite contain the sulphur-rich fraction. Design/methodology/approach In this study, the possibility of waste reprocessing using froth flotation of sulphuric bulk and depression-heavy minerals. It is environmental desulphurization that removes much of the high S fraction. Findings The results obtained in terms of S recovery and residual S content are interesting after merely 12 min of flotation by addition of potassium amyl xanthate collector (140 g/t), pine oil frother (10 g/t) and activation with copper sulphate (CuSO4+; 60 g/t) and at optimum pH of 5. Originality/value It can be shown from waste treatment by flotation of pyrite depression sphalerite collects significant desulphurization in sulphur content is 19 per cent against 8 per cent in the initial release.

Review on algae for biodiesel fuel production, its characteristics comparison with other and their impact on performance, combustion and emissions of diesel engine

Abstract: Purpose This study aims to find a new alternate source for biodiesel conversion. The alternate source must be easily available, and it should give more oil yield than available edible, inedible sources. To meet the fuel demand in the transportation sector with edible oil-based biodiesel causes food versus fuel crisis. In addition to this, it increases NOx and CO2 in the environment. Design/methodology/approach The present paper reviews the comparison of algae oil yield, fatty acid composition and its biodiesel properties’ effect on diesel engine characteristics. Findings Algae were the only source to fulfil fuel demand because its oil and biodiesel yield is higher than other sources. Algae can grow by capturing carbon dioxide from the environment, and its fatty acid composition is more suitable to run diesel engines. Originality/value There is an improvement in engine performance–emission tradeoff with algal biodiesel.

Relative complex permittivity and its dependence on frequency

Abstract: Purpose This paper aims to give a brief overview of dielectric properties, relative complex permittivity and its dependence on frequency. The significance of different approaches to complex permittivity is also discussed. Design/methodology/approach The different mechanisms of polarization are then presented. Dielectric measurements are given, and an RC parallel-equivalent circuit is used to simulate a parallel plate capacitor, and the way in which the impedance of the circuits is affected by frequency is illustrated in their respective diagrams. The way in which dielectric properties change with time is also discussed. Findings The goal of this paper is to give an overview of the characteristics of the dielectrics and how frequency affects the relative complex permittivity and to present different approaches to and equations for the relative complex permittivity, such as that of Debye, Cole–Cole, Cole–Davidson and Havriliak–Negami. In addition, three mechanisms of polarization, namely, electronic, atomic and bipolar, are presented. The most common dielectric characterization device, a capacitor with parallel plates between which the dielectric material under study is located, is also discussed. Ohmic and dielectric losses of a non-ideal capacitor are accounted for. Furthermore, this paper studies the equivalent circuits of a non-ideal parallel plate capacitor, those being a resistor and an ideal capacitor connected either in series or in parallel. Originality/value Finally, dielectric responses to both time and to stepwise excitation are given.

Effect of process parameters on the surface crack density of AISI 304 in PMEDM

Abstract: Purpose In this study, powder mixed electro discharge machining (PMEDM) has been performed for the machining of AISI 304 stainless steel by using the tungsten carbide electrode when silicon carbide (SiC) powder is mixed with kerosene. The purpose of this study is to find the optimal value and ascertain the effect of significant machining parameters on surface crack density (SCD) of a machined surface of AISI 304. Design/methodology/approach A face-centered central composite design-based response surface methodology has been adopted for designing this experiment. Findings An increase in peak current and powder concentration decreases SCD, which is the main goal of this investigation. Originality/value From this investigation, an optimal value has been achieved to minimize the SCD and prevent fatigue and corrosion resistance of the workpiece.

MHD flow and heat transfer of a magnetite–water nanofluid in porous medium under the effects of chemical reaction

Abstract: Purpose Due to the extensive industrial applications of stagnation flow problems, the present work aims to investigate the magnetohydrodynamics (MHD) flow and heat transfer of a magnetite nanofluid (here Fe3O4–water nanofluid) impinging a flat porous plate under the effects of a non-uniform magnetic field and chemical reaction with variable reaction rate. Design/methodology/approach Similarity transformations are applied to reduce the governing partial differential equations with boundary conditions into a system of ordinary differential equations over a semi-infinite domain. The modified fourth-order Runge–Kutta method with the shooting technique which is developed for unbounded domains is conducted to give approximate solutions of the problem, which are then verified by results of other researchers, showing very good agreements. Findings The effects of the volume fraction of nanoparticles, permeability, magnetic field, chemical reaction and Schmidt number on velocity, temperature and concentration fields are examined and graphically illustrated. It was found that fluid velocity and temperature fields are affected strongly by the types of nanoparticles. Moreover, magnetic field and radiation have strong effects on velocity and temperature fields, fluid velocity increases and thickness of the velocity boundary layer decreases as magnetic parameter M increases. The results also showed that the thickness of the concentration boundary layer decreases with an increase in the Schmidt number, as well as an increase in the chemical reaction coefficient. Research limitations/implications The thermophysical properties of the magnetite nanofluid (Fe3O4–water nanofluid) in different conditions should be checked. Practical implications Stagnation flow of viscous fluid is important due to its vast industrial applications, such as the flows over the tips of rockets, aircrafts, submarines and oil ships. Moreover, nanofluid, a liquid containing a dispersion of sub-micronic solid particles (nanoparticles) with typical length of the order of 1-50 nm, showed abnormal convective heat transfer enhancement, which is remarkable. Originality/value The major novelty of the present work corresponds to utilization of a magnetite nanofluid (Fe3O4–water nanofluid) in a stagnation flow influenced by chemical reaction and magnetic field. It should be noted that in addition to a variable chemical reaction, the permeability is non-uniform, while the imposed magnetic field also varies along the sheet. These, all, make the present work rather original.

Pyrolysis characteristic of coals with different metamorphic grades and its instruction to coalbed methane development

Abstract: Purpose Pyrolysis for coal gas generation changes the composition, pore structure, permeability and adsorption capacity of coal. This work aims to discuss the utilization of coal pyrolysis on enhancing coalbed methane (CBM) production in the Gujiao area, Shanxi province, China. Design/methodology/approach This research was conducted mainly by the methods of thermogravimetry mass spectrometry (TG-MS) analysis, liquid nitrogen adsorption experiment and methane isothermal adsorption measurement. Findings The results can be concluded as that 400-700°C is the main temperature range for generating CH4. Pore volume and specific surface area increase with increasing temperature; however, the proportion of micro pore, transition pore and macro pore has no difference. The optimum temperature for enhancing CBM production should be letter than 600°C because the sedimentation of tar and other products will occupy some pores and fissures after 600°C. Originality/value Here in, to accurately recognize the suitable maximum temperature for heating development, a method enhancing CBM production, TG-MS, was adopted to analyze the products and the weight loss of coals with different ranks in the Gujiao area at temperature of 30-1,100°C. And then the pore structure, porosity, permeability, methane adsorption capacity and thermal maturity of coals during pyrolysis were investigated with increased temperature from 30°C to 750°C. On these bases, the favorable condition for enhancing CBM production and the thermal evolution of coal were recognized.

Avian keratin fibre-based bio-composites

Abstract: Purpose This paper aims to use the solvent–casting–evaporation method to prepare new bio-composites with thermoplastic poly(ether urethane) (TPU-polyether) as the polymer matrix and reinforced with natural chicken feather fibre (CFF). Design/methodology/approach To produce the bio-composites, 0 to 60 per cent·w/w of fibres in steps of 30 per cent·w/w were added to the polymer matrix. The uniformity of distribution of the keratin fibres in the polymer matrix was investigated via scanning electron microscopy, and the results suggested compatibility of the TPU-polyether matrix with the CFFs, thereby implying effective fibre–polymer interactions. Findings Addition of natural fibres to the polymer was found to decrease the mass loss of the composites at higher temperatures and decrease the glass transition temperature, as well as the storage and loss modulus, at lower temperatures, while increasing the remaining char ratio, storage modulus and loss modulus at higher temperatures. Originality/value The investigation confirmed that waste keratin CFF can improve the thermo-mechanical properties of composites, simply and cheaply, with potentially large environmental and economic benefits.

Vibrational characterization of a human femur bone and its significance in the designing of artificial implants

Abstract: Purpose Being an interdisciplinary research area, biomechanics has gained interest among researchers. Biomechanics deals with integration of mechanical phenomenon with the structural and functional aspects of biological systems. Biological systems being very much complex provide a very intricate platform for their analysis. In case of damages created by accidents or sport malfunctions, artificial implants are used for the replacement of bones. These implants may cause incompatibility with the human body, depending on their design and characterization. So, this research aims to analyze the vibrational characteristics of a human femur bone and to predict the safe ranges of frequencies of operation. Design/methodology/approach The current research is aimed at vibrational characterization of a human femur bone. The model of the femur bone is prepared using SOLIDWORKS software. The material properties of the femur are collected from the available literature and provided with the CAD model. The model is imported to the ANSYS software. Loading patterns as applied on the human body are also applied to the prepared model. Suitable boundary conditions are chosen for normal sitting and standing positions. The natural frequencies of the femur bone and other vibrational parameters are found out. Findings The first data obtained from the ANSYS software are the natural frequencies and mode shapes of vibration. Other data include the stress distributions, strain distributions, deformation patterns and potential zones of damage. The frequencies and mode shapes enable the safe ranges of human operation and the frequency range to be followed in the designing of implants. The stress distributions enable to know the potential zones of damage so that those areas can be given focus during strength considerations. Research limitations/implications The current investigations take into account only normal sitting and walking conditions. This work can be included under static loadings. This can also be extended toward dynamic loading conditions. In the dynamic loading, walking and running conditions can be taken into account. This work focuses on the safe designing of the artificial implants and their compatibility with the human body. This can also be extended toward role of dynamic forces in the damaged bone formation and the role of implant’s characteristics for healing of bones. Practical implications Bone damage and ligament fracture are common nowadays due to increasing number of accidents, which may be vehicular or sports. In case of any damage to the skeletal parts, some artificial implant is used to support the damaged part and to help in the process of healing. The designing of the implants must be compatible with the human body. The natural frequencies and mode shapes give an idea that the vibrational parameters of the implant material must fall in the same range as the actual bone. The stress distribution and potential zone damage emphasize on strength considerations. Originality/value The current method is a novel approach toward implant designing. Here an analysis of vibrational parameters of the human femur bone is performed. Those parameters include natural frequencies, mode shapes, principal normal stress distributions, principal shear stress distributions, maximum shear elastic strains and total deformation. These parameters reflect an idea about behavior of the femur bone under actual loading conditions. This analysis enables an implant designer to focus on material properties and strength considerations of the implants which are to be used in case of bone damage.

Compositional and experimental investigation of the effect of reactor temperature on softwood and hardwood pyrolysis

Abstract: This study aims to investigate the effect of reactor temperature on softwood and hardwood pyrolysis. Experiments are performed at six temperature levels ranging from 300 to 800°C under N2 atmosphere. The weights of char, tar and gas yields produced were measured and recorded in percentage of initial weight of the pyrolyzed samples. Results of the study showed that hardwood produces maximum char, tar and gas yields of 41.02 per cent at 300°C,44.10 per cent at 300°C and 56.86 per cent at 800°C, respectively, whereas softwood produces maximum yields of 30.10 per cent at 300°C, 28.25 per cent at 300°C and 68.73 per cent at 800°C, respectively. Proximate analysis shows that volatile matter, fixed carbon, ash content and moisture content of hardwood are 74.83, 14.28, 2.81 and 8.08 per cent, respectively, and that of softwood are 79.76, 12.65, 0.98 and 6.61 per cent, respectively. Result of the elemental analysis results shows that the carbon, hydrogen, nitrogen, oxygen and sulphur contents for hardwood are 52.20, 6.45, 0.68, 39.64 and 1.03 per cent, respectively, and that of softwood are 45.95, 4.57, 0.56, 48.13 and 0.79 per cent, respectively. The higher heating value of hardwood and softwood are 21.76 and 16.50 kJ/g respectively. This study shows that char and tar yields decrease with increase pyrolysis temperature, whereas gas yield increases as pyrolysis temperature increases for the wood samples considered. At all temperatures considered in this study, gas yields are higher than tar and char yields for softwood, whereas for hardwood, tar yield decreases with increase in temperature with accompanying increase in gas yield.,Experiments are performed at six temperature levels ranging from 300 to 800°C under N2 atmosphere.,At all temperatures considered in this study, gas yields are higher than tar and char yields for softwood, whereas for hardwood, tar yield decreases with increase in temperature with accompanying increase in gas yield.,Results of the study showed that hardwood produces maximum char, tar and gas yields of 41.02 per cent at 300°C,44.10 per cent at 300°C and 56.86 per cent at 800°C, respectively, whereas softwood produces maximum yields of 30.10 per cent at 300°C, 28.25 per cent at 300°C and 68.73 per cent at 800°C, respectively.

Computational contact mechanics analysis of laterally graded orthotropic half-planes

Abstract: Purpose Frictional sliding contact problems between laterally graded orthotropic half-planes and a flat rigid stamp are investigated. The presented study aims at guiding engineering applications in the prediction of the contact response of orthotropic laterally graded members. Design/methodology/approach The solution procedure is based on a finite element (FE) approach which is conducted with an efficient FE analysis software ANSYS. The spatial gradations of the orthotropic stiffness constants through the horizontal axis are enabled utilizing the homogeneous FE approach. The Augmented Lagrangian contact algorithm is used as an iterative non-linear solution method in the contact analysis. Findings The accuracy of the proposed FE solution method is approved by using the comparisons of the results with those computed using an analytical technique. The prominent results indicate that the surface contact stresses can be mitigated upon increasing the degree of orthotropy and positive lateral gradations. Originality/value One can infer from the literature survey that, the contact mechanics analysis of orthotropic laterally graded materials has not been investigated so far. In this study, an FE method-based computational solution procedure for the aforementioned problem is addressed. The presented study aims at guiding engineering applications in the prediction of the contact response of orthotropic laterally graded members. Additionally, this study provides some useful points related to computational contact mechanics analysis of orthotropic structures.

Bio-oil production from fast pyrolysis of maple fruit (acer platanoides samaras): product yields

Abstract: Purpose The purpose of this paper is to investigate fast pyrolysis of maple fruit as an energy sources. This could serve as a solution to the energy sources problem. Design/methodology/approach Fast pyrolysis of maple fruit (samara) was achieved in a fixed bed reactor. The pyrolysis experiments have been conducted on the sample of maple seeds to particularly determine the effects of pyrolysis temperature, particle size and sweep gas flow rate on the pyrolysis product yields. Findings The oil of maple fruit from fast pyrolysis has good properties to be a potential candidate as a biofuel or as a source of chemicals. In addition to being environmentally desirable, it can reduce the energy cost, e.g. that Turkey imports a majority of its energy. Originality/value The use of maple fruit for fast pyrolysis and pyrolysis conditions impact on the yields of pyrolysis liquid can be considered as novel aspects of this paper.

Map risks in the company: highlight at the top priority risks

Abstract: Purpose Today, methods and risk analysis tools are used to argue decisions concerning issuance of operating licenses, risk management and development of action and emergency plans. In practice, a company is looking for a tool to help in decision-making and in the development of action plans. Thus, the creation of a safe working environment is essential to a company’s success and is one of the best ways to attract/retain staff and increase productivity. It should then set up a kind of funnel sieve that allows understanding all risks to keep only the most significant, which should be given priority. Thus, global risk management should be based on an accurate diagnosis of all company risks. This diagnosis can be formalized in the form of a risk map. The latter is crucial because it raises the overall risk identification, assessment, prioritization and prioritization of action. It is an essential component of any company’s risk management processes. The objective is to have an overall inventory (entity, system, process, activity, etc.) of the vulnerabilities of all fields of activity. It offers a simple and didactic presentation, giving an overview to decision-makers to guide their strategic choices of action. This mapping is then used to monitor the effectiveness of strategies implemented, forming, in a very relevant tool for communication, the objective assessment of this work. So, the purpose of this study is to describe a methodology for comprehensive risk analysis, called risk map. The purpose of this work is to provide a decision support tool to identify areas of weaknesses to allow setting priorities for action to be undertaken by the company to improve the working conditions by organizational, technical and human solutions while engaging in a process of continuous improvement. Design/methodology/approach The proposed approach for the development of a risk map comprises five stages: risk identification, where the starting point is the identification of the main company processes or, alternatively, the main company activities; exhibition evaluation, the company counts then evaluate the most important risks that affect their processes or activities and persons; evaluation and prioritization of risks; action plan, the company implements the action plan developed on the basis of the prioritization of risks and the company identifies the solutions implemented to reduce the risk and evaluates; and actions control. Findings This study allows making an image of overall places with vulnerabilities inside the company by a simple and didactic representation, facilitating the promotion of a culture of communication regarding the company vulnerabilities. The development of this risk mapping allowed the development of a very useful tool of communication on the inventory for formulating a risk appetite and determining the risk profile. It is a tool for decision and action whose purpose is the improvement of working conditions by organizational solutions, technical and human resources for the health and safety of employees while engaging in a process of continuous improvement. Research limitations/implications The limitations of this study include the lack of competence in risk concepts. It is enough to have a pludisciplinary team to highlight the various dangers and move to the priorities and engage in a process of continuous improvement. Practical implications The approach detailed in this study can be used in any entity. One just needs to have skills. Social implications Low level of work accidents, a pleasant working environment, a very good motivation, a good productivity at work. Originality/value This work intends to reflect the concrete situation in which companies face the risks. It is interested in the relations between scientific expertise and the precautionary principle. It is a tool that guarantees the success of any preventive approach in a company. It is a decision-making tool for identifying areas of weakness to establish priorities for action by a company whose aim is to improve the working conditions through organizational, technical and human resources while engaging in a process of continuous improvement.

Hazard identification and risk analysis for a reinforced concrete rolling mill

Abstract: Purpose Because of non-satisfactory results obtained at the iron rods steel mill, during the last period of work and to collect relevant data to facilitate rapid and efficient decision-making, the purpose of this study is to describe a global analysis method of risks encountered by companies resulting from their own effects or by their environment to integrate prevention as soon as the conception of work place. From this point of view, it seems that it is time for companies that did learn to master direct costs to learn how to control indirect costs, which means controlling the risks and learning to face them once they are detected. Design/methodology/approach The method of work used is hazard identification and risk assessment (HIRA), which is based on Kinney evaluation. The HIRA allowed the authors to collect and analyze different dangers and risks at work posts and consider different corrective measures to prevent damages. The HIRA techniques are based on identifying the different hazardous situations and the risk related to each working station; the risks are identified and are classified and mitigated accordingly. Using unique criteria, the objective of the risk assessment part is to assign to each risk a numerical value. The criteria used for classifying and ordering the risk importance depend greatly on the selected method. Findings Risks are identified, classified and mitigated accordingly using Kinney method criteria depending on three factors: frequency of exposure (NE), probability of occurrence (NP) and severity level (NG). The level of risk mitigation (NM) is obtained as the product of the three factors (NP, NG and NE). Using the Pareto plot (20-80 per cent), the authors highlighted the priorities to be taken in the order of importance of the most important causes to take targeted measures. Originality/value This work is an opportunity for the steel mill complex to start a global approach in prevention of risks and improve working conditions. This can be reached by taking into consideration the technical, organizational and human solutions; It would not be a better method to search for ways and means to reach better prevention of industrial and technological risks, but it will preserve health of workers and get to a global higher level of security. Also, the steel mill complex can be engaged in a continuous improvement process. Therefore, management of risks will be a relevant way to decrease undesirable effects due to the diverse activities of the company.

Mechanical behavior and damage mechanism of loaded coal and rock

Abstract: Purpose The purpose of this paper is to obtain the mechanical behavior and damage mechanism of the coal and rock near the stope under the stress state and stress paths of the surrounding rock with the dynamic mining. Design/methodology/approach Through the three-axial compression test and the uniaxial compression test by meso experiment device, the mechanical behavior and fracture evolution process of coal and rock were studied, and the acoustic emission (AE) characteristics under uniaxial compression of the coal and rock were contrasted. Findings Under the three-axial compression, the strength of coal and rock enhance significantly by confining pressure. The volume of outburst coal shows obvious stages: compression is followed by expansion. The coal first appear to undergo compaction under vertical stress due to volume decrease, but with the development of micro- and macro-cracks, the specimens appeared to expand; under the uniaxial compression, through the comparison of stress–strain relationship and the crack propagation process, stress drop and fracture of coal have obvious correlation. The destruction of coal was gradual due to the slow and steady accumulation of internal damage. Due to the influence of the end effect, the specimens show the “conjugate double shear failure”. The failure process of the coal and rock and the characteristics of the AEs have a corresponding relationship: the failure causes a large number of AE events. Before the events peak, there was an initial stage, calm growth stage and explosive growth stage. There were some differences between the rock and coal in the characteristics of the AE. Originality/value These research studies are conducted to provide guidance on the basis of mine disaster prevention and control.

Geometrically nonlinear analysis of shells by various dynamic relaxation methods

Abstract: Purpose Numerical experiences reveal that the performances of the dynamic relaxation (DR) method are related to the structural types. This paper is devoted to compare the DR schemes for geometric nonlinear analysis of shells. To achieve this task, 12 famous approaches are briefly introduced. The differences among these schemes are between the estimation of the time step, the mass and the damping matrices. In this study, several benchmark structures are analyzed by using these 12 techniques. Based on the number of iterations and the analysis duration, their performances are graded. Numerical findings reveal the high efficiency of the kinetic DR (kdDR) approach and Underwood’s strategy. Design/methodology/approach Up to now, the performances of various DR algorithms for geometric nonlinear analysis of thin shells have not been investigated. In this paper, 12 famous DR methods have been used for solving these structures. It should be noted that the difference between these approaches is in the estimation of the fictitious parameters. The aforementioned techniques are used to solve several numerical samples. Then, the performances of all schemes are graded based on the number of iterations and the analysis duration. Findings The final ranking of each strategy will be obtained after studying all numerical examples. It is worth emphasizing that the number of iterations and that of convergence points of the arc length algorithms are dependent on the value of the initial arc length. In other words, a slight change in the magnitude of the arc length may lead to the wrong responses. Contrary to this behavior, the analyzer’s role in the dynamic relaxation techniques is considerably less than the arc length method. In the DR strategies when the answer approaches the limit points, the iteration number increases automatically. As a result, this algorithm can be used to analyze the structures with complex equilibrium paths. Research limitations/implications Numerical experiences reveal that the DR method performances are related to the structural types. This paper is devoted to compare the DR schemes for geometric nonlinear analysis of shells. Practical implications Geometric nonlinear analysis of shells is a sophisticated procedure. Consequently, extensive research studies have been conducted to analyze the shells efficiently. The most important characteristic of these structures is their high resistance against pressure. This study demonstrates the performances of various DR methods in solving shell structures. Originality/value Up to now, the performances of various DR algorithms for geometric nonlinear analysis of thin shells are not investigated.

Preparation of TiO2/ZnO composite catalysts and their photocatalytic activity for degradation of pentachlorophenol

Abstract: Purpose This paper aims to report a novel preparation method of titanium dioxide (TiO2)/zinc oxide (ZnO) composites with different mole ratios of TiO2:ZnO and their photocatalytic activity. Design/methodology/approach TiO2/ZnO composites are prepared by a facile route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultra-violet–visible diffuse reflectance spectra (UV-vis DRS) are used to characterize the products. Photocatalytic activity of the samples is evaluated by degradation of persistent organic pollutant pentachlorophenol under ultra-violet (UV) irradiation. Findings It is found that all the as-prepared TiO2/ZnO composites not only have good catalytic activity under UV light irradiation, but also have excellent circulation stability. The optimal mole ratio of TiO2:ZnO is 0.75:1. Originality/value This report presents a simple and rapid method for the preparation of TiO2/ZnO composites with excellent photocatalytic activity. Experimental results could provide useful reference for the treatment of chlorophenols in the future.

Comparative performance studies on DI diesel engine with neem de-oiled cake and Jatropha methyl ester diesel blends

Abstract: Purpose Alternative sources for petroleum fuels have been the prime concern of most of the environmentalists. It is also a concern for economists due to the depletable nature of the fossil fuel. Vegetable oils are considered as good alternatives to diesel as their properties are close to diesel. This work aimed to produce a fuel by adding different proportions of de-oiled neem cake with diesel and to conduct experiments to find out its performance, emission and combustion characteristics. Design/methodology/approach At present, biodiesel is commercially produced from the vegetable oils by esterification processes. Because most of these oils are edible, its cost restricts the usage. The de-oiled cakes after crushing the seeds containing around 2 per cent of oil with less fatty materials are aimed in this study. Findings The fuel is prepared by adding dry neem de-oiled cake powder at different proportions ranging from 3 to 25 per cent by weight with diesel. Experimental results reveal that the fuel has the potential to reduce smoke, CO emissions simultaneously along with marginal increase in brake thermal efficiency. Originality/value In this published research work, the neem oil is used as biodiesel blends with diesel. Here, the authors have used neem de-oiled cake as a replacement for diesel.

A probabilistic study on the geometrical design of gravity retaining walls

Abstract: Purpose The purpose of this study is to introduce a relatively simple method of probabilistic analysis on the dimensions of gravity retaining walls which might lead to a more accurate understanding of failure. Considering the wall geometries in the case of allowable stress design, the probability of wall failure is not clearly defined. The available factor of safety may or may not be sufficient for the designed structure because of the inherent uncertainties in the geotechnical parameters. Moreover, two cases of correlated and uncorrelated geotechnical variables are considered to show how they affect the results. Design/methodology/approach This study is based on the failure and stability of gravity retaining walls which can be stated in three different modes of sliding, overturning and the foundation-bearing capacity failure. Each of these modes of failure might occur separately or simultaneously with a corresponding probability. Monte Carlo simulation and Taylor series method as two conventional methods of probability analysis are implemented, and the results of an assumed example are calculated and compared together. Findings The probability analysis of the failure in each mode is calculated separately and a global failure mode is introduced as the occurrence of three modes of sliding, overturning and foundation-bearing capacity failure. Results revealed that the global mode of failure can be used along with the allowable stress design to show the probability of the worst failure condition. Considering the performance and serviceability level of the retaining structure, the global failure mode can be used. Furthermore, the correlation of geotechnical variables seems to be relatively more dominant on the probability of global failure comparing to each mode of failure. Originality/value The introduced terminology of global mode of failure can be used to provide more information and confidence about the design of retaining structures. The resulted graphs maintain a thorough insight to choose the right dimensions based on the required level of safety.

The relationship of paleontology, palaeobotany and coal thickness of Taiyuan Formation, Late Carboniferous – Early Permian in Shanxi Province

Abstract: Purpose The purpose of this paper is to find the relationship of palaeontology, palaeobotany and coal thickness of Taiyuan Formation during Late Carboniferous – Early Permian Period in Shanxi Province. Design/methodology/approach This paper selects three regions, namely, Baode, Xishan and Lingchuan, to analyse the distribution characteristics of palaeontology, palaeobotany and variation of coal thickness. Findings It was found that in a certain period of geological history, palaeontology and palaeobotany play a dominant role in shaping of a coal-bearing basin. Coal seam thickness changes largely from the northwest to the southeast, gradually thinning in Taiyuan Formation. Originality/value Palaeontology and palaeobotany play a dominant role in the shaping of a coal-bearing basin.

Finite element analysis of nanosecond pulsed laser ablation of various materials

Abstract: Purpose The purpose of this paper is to analyse nanosecond pulsed laser ablation on both metallic materials and non-metallic materials; a comparison between metallic materials and non-metallic materials has also been included. Design/methodology/approach In this paper, FEM method has been used to calculate the result by means of the finite element method. Furthermore, all the analyses are based on thermal theories. Findings The paper presents a comparison of metallic and non-metallic materials. Besides, the effect of how laser parameter changes would influence the ablation depth has also been assessed. Research limitations/implications All studies in this paper are based on classical thermal theories. Thermal theories are not applicable some times. Originality/value With the results of this paper, suggestions are made so that experiments and manufactures could be optimised and improved.