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Article
Publication date: 11 April 2022

Manjeet Kumar, Xu Liu, Manjeet Kumari and Poonam Yadav

The purpose of this paper is to investigate propagation characteristics of seismic waves at the welded interface of an elastic solid and unsaturated poro-thermoelastic solid.

Abstract

Purpose

The purpose of this paper is to investigate propagation characteristics of seismic waves at the welded interface of an elastic solid and unsaturated poro-thermoelastic solid.

Design/methodology/approach

A theoretical formulation of partially saturated poro-thermoelastic solid is used in this study established by Zhou et al. (2019). The incidence of two primary waves (P and SV) is taken. The incident wave from the elastic solid induces two reflected waves and five refracted waves. Due to viscous pore fluids, partially saturated poro-thermoelastic solid behave dissipative, whereas elastic solid behaves non-dissipative. As a result, both reflected and incident waves are homogeneous. However, all the refracted waves are inhomogeneous. A non-singular system of linear equations is formed by the coefficients of reflection and refraction for a specified incident wave. The energy shares of various reflected and refracted waves are determined by using these reflection and refraction factors. Finally, a sensitivity analysis is performed, and the effect of critical variables on energy partitioning at the interface is observed. The numerical example shows that throughout the process of reflection/refraction, the energy of incidence is conserved at all angles of incidences.

Findings

This study demonstrated two refracted (homogeneous) and five refracted (inhomogeneous) waves due to the incident wave from elastic solid. The reflection and refraction coefficients and partitioning of incident energy are acquired as a part of diverse physical parameters of the partially saturated poro-thermoelastic media. The interference energies between unlike pairs of refracted waves have been discovered due to the dissipative behavior of unsaturated poro-thermoelastic solid.

Originality/value

The sensitivity of different energy shares to various aspects of the considered model is graphically analyzed for a specific numerical model. The energy balance is maintained by combining interaction energy and bulk wave energy shares.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 June 2005

A.V. Kuznetsov and P. Geng

To investigate numerically the settling of small solid particles in a suspension of motile gyrotactic micro‐organisms in order to evaluate the possibility of using…

Abstract

Purpose

To investigate numerically the settling of small solid particles in a suspension of motile gyrotactic micro‐organisms in order to evaluate the possibility of using bioconvection to slow down settling and enhance mixing between particles.

Design/methodology/approach

Numerical computations are performed at the North Carolina Supercomputing Center utilizing an Origin 2400 workstation. A conservative finite‐difference scheme is used to discretize the governing equations. A staggered uniform grid with the stream function and vorticity stored in one set of nodes and the number densities of micro‐organisms and solid particles stored in another set of nodes is utilized. CPU time required to investigate plume development until it attains steady‐state for 36 × 36 uniform mesh is about 50 h.

Findings

It is established that small solid particles that are heavier than water slow down bioconvection. Extremely small particles (nanoparticles) that have negligible settling velocity do not have any noticeable impact on bioconvection, very large particles (that have negligible diffusivity), or very heavy particles (that have very large settling velocity) also do not have any impact on bioconvection because they simply settle at the bottom. However, if the particles are of the optimal size and density (gravitational settling must compete with Brownian diffusion to create an exponential number density distribution of solid particles with the maximum at the bottom of the chamber), these particles can effectively slow down bioconvection.

Research limitations/implications

The question how solid particles may affect the wavelengths of bioconvection patterns requires further investigation.

Practical implications

The finding that solid particles slow down bioconvection may be important in using bioconvection to enhance mixing in fluid microvolumes.

Originality/value

The paper provides a model and numerical data about the effect of bioconvection on mixing of small solid particles. These data are valuable for researches working in fundamental fluid mechanics, multiphase flow, and applications of bioconvection.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 15 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 8 August 2016

Mayurkumar Ashwinbhai Makhesana and Kaushik M. Patel

The quality of the surface being machined and tool life are greatly affected by heat generated during machining. Abundant use of cutting fluid leads to higher production…

Abstract

Purpose

The quality of the surface being machined and tool life are greatly affected by heat generated during machining. Abundant use of cutting fluid leads to higher production rates and a threat for environment and worker’s health. Hence, the need is to identify eco-friendly lubricants. The purpose of the current work is to investigate the effects of solid lubricants (boric acid and molybdenum disulphide) mixed with oil during turning of EN-31 using cemented carbide tools. The concentration of solid lubricants in oil is varied to analyze output parameters such as surface roughness, process temperature, power consumption and tool wear.

Design/methodology/approach

EN 31 steel material is machined at various cutting speeds and constant feed and depth of cut to determine the effects of dry, wet and solid lubricant assisted machining.

Findings

Experimental study revealed that the solid lubricants performed better while machining and therefore it may be considered as environment friendly and cost effective way of lubrication as compared to flood cooling.

Research limitations/implications

The work can be extended to identify the effects of solid lubricants on micro hardness and cutting force.

Practical implications

From the findings of the work, solid lubricants may be considered as suitable choice as compared to fluid cooling because it improves process performance without much affecting the environment and worker’s health.

Originality/value

So far the use of solid lubricants in machining is limited. The results of the work will be useful to explore various efficient way to apply solid lubricants.

Details

Industrial Lubrication and Tribology, vol. 68 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 February 2000

Joo‐Sik Yoo

The problem of transient heat transfer and growth of solid in the inviscid stagnation flow when phase change from liquid to solid occurs is considered. A fast and accurate…

Abstract

The problem of transient heat transfer and growth of solid in the inviscid stagnation flow when phase change from liquid to solid occurs is considered. A fast and accurate numerical scheme is developed to determine the instantaneous temperature distribution in both solid and liquid phases and the growth rate of solid directly, without iterative calculation. The solution of the dimensionless governing equations is dependent on the three dimensionless parameters. The characteristics of the transient heat transfer and solidification process for all the parameters are elucidated.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 10 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Abstract

Details

Energy Economics
Type: Book
ISBN: 978-1-78756-780-1

Article
Publication date: 27 November 2020

Abdelraheem M. Aly and Ehab Mahmoud Mohamed

The purpose of this study is to use an incompressible smoothed particle hydrodynamics (ISPH) method for simulating buoyancy ratio and magnetic field effects on double…

Abstract

Purpose

The purpose of this study is to use an incompressible smoothed particle hydrodynamics (ISPH) method for simulating buoyancy ratio and magnetic field effects on double diffusive natural convection of a cooper-water nanofluid in a cavity. An open pipe is embedded inside the center of a cavity, and it is occupied by solid particles.

Design/methodology/approach

The dimensionless governing equations in Lagrangian form were solved by ISPH method. Two different thermal conditions were considered for the solid particles. The actions of the solid particles were tracked inside a cavity. The effects of Hartman parameter, Rayleigh number, nanoparticles volume fraction and Lewis number on features of heat and mass transfer and flow field were tested.

Findings

The results showed that the buoyancy ratio changes the directions of the solid particles diffusion in a cavity. The hot solid particles were raised upwards at aiding mode (N > 0) and downwards at an opposing mode (N < 0). A comparison is made with experimental and numerical simulation results, and it showed a well agreement.

Originality/value

Novel studies for the impacts of buoyancy ratio on the diffusion of solid particles embedded in an open pipe during double-diffusive flow were conducted.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 9 April 2018

Gahana Gopal C., Yogesh B. Patil, Shibin K.T. and Anand Prakash

The purpose of this paper is to formulate frameworks for the drivers and barriers of integrated sustainable solid waste management (ISSWM) with reference to conditions…

1008

Abstract

Purpose

The purpose of this paper is to formulate frameworks for the drivers and barriers of integrated sustainable solid waste management (ISSWM) with reference to conditions prevailing in India.

Design/methodology/approach

A multi-phased approach was adopted in this paper to come up with the conceptual framework of the drivers and barriers of ISSWM. In the first phase, drivers and barriers of ISSWM were identified based on a systematic literature review process. In the second phase, 25 experts having 15 plus years of experience in the field of sustainable development and environmental management were consulted to get their opinion. Validation and understanding of the interrelationship among the selected drivers and barriers were done based on the insights from expert interviews. And in the final phase, structural self-interaction matrix and transitive links are defined based on the expert opinion to come up with the theoretical frameworks of drivers and barriers of ISSWM.

Findings

Findings reveal the importance to have a system view point approach by giving equal importance to social, environmental and economic pillars of sustainability along with the technology component to effectively and sustainably manage the solid waste disposal. Institutional effectiveness and the robust policy and frameworks are the two variables found to have the highest driving power. Poor social values and ethics, huge population and illiteracy are the three most critical barriers faced by developing nations in achieving the sustainability practices in the solid waste management. The proposed frameworks of drivers and barriers of ISSWM will definitely help policy makers to effectively manage the sustainable waste management practices for developing economies by focusing on the key variables listed out.

Research limitations/implications

One of the limitations is in the use of very limited sample size in the study. Another limitation is that total interpretive structural modeling fails to come up with the relative weightings of drivers and barriers used in the study. These limitations can be overcome by extending the research by using a semi-structured questionnaire survey with higher sample size for the empirical validation of the model.

Practical implications

This research will help to clearly understand the framework of drivers and barriers of variables and their hierarchical level based on the driving power and dependence. Since such articles focusing on the conceptual frameworks of drivers and barriers of ISSWM are found to be very scant, this paper will equally help academicians and waste management professionals to understand the concepts deeply, by getting answers to the fundamental questions of “what,” “why” and “how.” Developed framework of drivers explicitly shows the need to attain financial stability through the commercialization of the waste management initiatives, which will help to reduce burden on various governmental institutions. Commercialization opportunities will also help to have more successful start-up ventures in solid waste management domain that can provide improved employment opportunities and hygiene environment in the developing nations like India.

Originality/value

Based on the authors’ best knowledge, there is hardly any article that explicitly explains the conceptual frameworks of the drivers and barriers of ISSWM by considering the conditions prevailing in developing countries like India. And thus, this can be considered as one of the unique research attempts to build a clear conceptual framework of ISSWM. The study contributes significantly to the existing literature body by clearly interpreting the interrelationships and the driving power and dependence of variables of ISSWM.

Details

Management of Environmental Quality: An International Journal, vol. 29 no. 3
Type: Research Article
ISSN: 1477-7835

Keywords

Article
Publication date: 12 January 2015

Charles Chidozie Nnaji

This paper examined the current status of municipal solid waste management across Nigeria. The core aspects covered are generation, characterization, collection…

2667

Abstract

Purpose

This paper examined the current status of municipal solid waste management across Nigeria. The core aspects covered are generation, characterization, collection, scavenging, open dumping, disposal and environmental implications of poor solid waste management. The purpose of this paper is to present a comprehensive overview of the current state of municipal solid waste management in Nigeria.

Design/methodology/approach

This study was executed by a combination of an extensive literature search and field study. Solid waste generation rates for 31 Nigerian cities were obtained from literature. In addition, characteristics of municipal solid waste from 26 Nigerian cities were also obtained from literature. Other aspects such as characterization of solid waste obtained from final dumpsite and heavy metals accumulation in solid waste dumpsites were undertaken first hand.

Findings

Solid waste generation rate was found to vary from 0.13 kg/capita/day in Ogbomosho to 0.71 kg/capita/day in Ado-Ekiti. Factors affecting solid waste generation rates were identified. Typically, food waste was found to constitute close to 50 percent of overall municipal solid waste in Nigerian cities. This study shows that the rate of generation of plastics, water proof materials and diapers has assumed an upward trend. Due to the dysfunctional state of many municipal waste management authorities, many cities have been overrun by open dumps. For instance, more than 50 percent of residents of Maiduguri in northern Nigeria and Ughelli in southern Nigeria dispose of their waste in open dumps. Indiscriminate disposal of waste has also resulted in the preponderance of toxic heavy metals in agricultural soils and consequent bioaccumulation in plants as well as groundwater contamination.

Research limitations/implications

The main limitation of this research is municipal waste management authorities do not have relevant data. Hence, there was heavy reliance on published materials. The status of waste management in Nigeria is very deplorable and therefore poses serious threats to public and environmental health. There is urgent need for both government and individuals to adopt holistic and sustainable waste management strategies in order to safeguard public/environmental health.

Practical implications

Findings from this paper can form a veritable resource for the formulation and implementation of sustainable municipal solid waste management framework and strategies in Nigeria.

Originality/value

While most studies on municipal solid waste management in Nigeria are focussed on selected cities of interest, this particular study cuts across most cities of Nigeria in order to present a broader and holistic view of municipal solid waste management in Nigeria. The paper has also unraveled core municipal solid waste management challenges facing Nigerian cities.

Details

Management of Environmental Quality: An International Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1477-7835

Keywords

Article
Publication date: 5 August 2014

B.K. Prasad

The purpose of the paper is to assess the influence of the volume fraction solid lubricants like talc lead and graphite in oil separately and in combination towards…

Abstract

Purpose

The purpose of the paper is to assess the influence of the volume fraction solid lubricants like talc lead and graphite in oil separately and in combination towards controlling the sliding wear behaviour of a grey cast iron and understand the factors controlling the response of the material in a given set of experimental conditions.

Design/methodology/approach

The composition of the lubricating medium (oil) has been changed by dispersing 5 per cent graphite, talc and lead particles separately and in combination. Sliding wear tests were conducted on grey cast iron samples over a range of applied pressures. Parameters determined were wear rate and frictional heating. The wear behaviour of the samples was further substantiated through the features of wear surfaces, subsurface regions and debris particles. Material removal mechanisms and factors responsible for a specific response of the samples have also been analysed.

Findings

The wear rate increased with increasing applied pressure. Addition of graphite and lead to the oil separately or in combination brought about a reduction in the wear rate of the samples; talc and talc + lead produced a reverse trend. Temperature near the specimen surface increased with test duration and applied pressure. The test environment influenced the frictional heating in a manner similar to that of the wear rate. Adhesion and abrasion were observed to be the operating material removal mechanisms. Smearing of the solid lubricating phase and delamination resulting from cracking tendency also controlled the wear response.

Research limitations/implications

Oil is a very popular lubricant used in engineering applications involving friction and wear. Solid lubricants are used along with the oil. The nature, characteristics and content of the solid lubricants very much control the performance. Limited information is available pertaining to assessing the influence of the type and fraction of solid lubricants in the oil towards controlling the wear behaviour of cast irons (popularly known tribomaterials). The present study enables to understand the effectiveness of talc, lead and graphite in oil towards governing the wear characteristics of cast iron and analyse wear mechanisms and controlling parameters.

Practical implications

Graphite and talc are available in nature in abundance. Graphite is a popularly known solid lubricant, while talc is less explored. Lead is also well-known as a solid lubricant but poses health hazard in practice due to its toxic nature. The present study explores the lubricating capability of talc when mixed with oil separately or in combination with lead and graphite towards controlling the wear response of a grey cast iron. It enables to understand the factors responsible for the specific response of talc.

Social implications

Assessment of the lubricating potential of talc as a possible substitute to lead is important in view of the toxic nature of the latter. If successful, the exercise could enable to replace lead with talc.

Originality/value

The present manuscript is an original piece of the author's research work.

Details

Industrial Lubrication and Tribology, vol. 66 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 March 1977

Sarojini Balachandran

Environmental engineering is primarily concerned with the application of technology to the urgent tasks of cleaning up our environment. Its practitioners generally attempt…

Abstract

Environmental engineering is primarily concerned with the application of technology to the urgent tasks of cleaning up our environment. Its practitioners generally attempt to cope with the problems of streams and waterways polluted by sewage and industrial waste, oceans damaged by oil spills and sewage sludge dumpings, air polluted with noxious fumes and land abused by solid waste disposal. But that is not all that they do. The recent energy crisis has sharply brought into focus the need for alternate energy strategies, including energy extraction from solid waste. Under current estimates, the United States will produce approximately 340 million tons of solid waste by 1980. This is equivalent to one ton of solid waste per person per year. The most widely used methods of waste disposal right now are dumping, incineration and sanitary landfill. They are expensive and they cause pollution. Instead, solid waste can be burned to produce steam which can be used for heating or to generate electricity. It can also be converted to pyrolysis gas or oil, which can be stored or transported. It is from this standpoint that environmental engineering assumes considerable importance. A report which presents an overview of the state of the art in this area is the Resource Recovery from Municipal Solid Waste. Other pertinent guides include Energy from Solid Waste, Conversion of Refuse to Energy, Recycling and Reclaiming of Municipal Solid Wastes, Resource Recovery and Recycling Handbook of Industrial Wastes, and Wasteheat Management Guidebook. No project of this nature can be undertaken without government assistance. A description of the activities of the Federal Solid Waste Management Program is available from EPA's Solid Waste Recycling Projects: A National Directory.

Details

Reference Services Review, vol. 5 no. 3
Type: Research Article
ISSN: 0090-7324

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