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Article
Publication date: 21 January 2020

Younes Menni, Ali J. Chamkha, Nicola Massarotti, Houari Ameur, Noureddine Kaid and Mohammed Bensafi

The purpose of this paper is to carry out a hydrodynamic and thermal analysis of turbulent forced-convection flows of pure water, pure ethylene glycol and water-ethylene glycol…

Abstract

Purpose

The purpose of this paper is to carry out a hydrodynamic and thermal analysis of turbulent forced-convection flows of pure water, pure ethylene glycol and water-ethylene glycol mixture, as base fluids dispersed by Al2O3 nano-sized solid particles, through a constant temperature-surfaced rectangular cross-section channel with detached and attached obstacles, using a computational fluid dynamics (CFD) technique. Effects of various base fluids and different Al2O3 nano-sized solid particle solid volume fractions with Reynolds numbers ranging from 5,000 to 50,000 were analyzed. The contour plots of dynamic pressure, stream-function, velocity-magnitude, axial velocity, transverse velocity, turbulent intensity, turbulent kinetic energy, turbulent viscosity and temperature fields, the axial velocity profiles, the local and average Nusselt numbers, as well as the local and average coefficients of skin friction, were obtained and investigated numerically.

Design/methodology/approach

The fluid flow and temperature fields were simulated using the Commercial CFD Software FLUENT. The same package included a preprocessor GAMBIT which was used to create the mesh needed for the solver. The RANS equations, along with the standard k-epsilon turbulence model and the energy equation were used to control the channel flow model. All the equations were discretized by the finite volume method using a two-dimensional formulation, using the semi-implicit method for pressure-linked equations pressure-velocity coupling algorithm. With regard to the flow characteristics, the interpolation QUICK scheme was applied, and a second-order upwind scheme was used for the pressure terms. The under-relaxation was changed between the values 0.3 and 1.0 to control the update of the computed variables at each iteration. Moreover, various grid systems were tested to analyze the effect of the grid size on the numerical solution. Then, the solutions are said to be converging when the normalized residuals are smaller than 10-12 and 10-9 for the energy equation and the other variables, respectively. The equations were iterated by the solver till it reached the needed residuals or when it stabilized at a fixed value.

Findings

The result analysis showed that the pure ethylene glycol with Al2O3 nanoparticles showed a significant heat transfer enhancement, in terms of local and average Nusselt numbers, compared with other pure or mixed fluid-based nanofluids, with low-pressure losses in terms of local and average skin friction coefficients.

Originality/value

The present research ended up at interesting results which constitute a valuable contribution to the improvement of the knowledge basis of professional work through research related to turbulent flow forced-convection within channels supplied with obstacles, and especially inside heat exchangers and solar flat plate collectors.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 January 1903

The Daily Telegraph has recently published several articles and a considerable amount of correspondence relating to malt whisky and the tricks of the whisky trade. As is usually…

Abstract

The Daily Telegraph has recently published several articles and a considerable amount of correspondence relating to malt whisky and the tricks of the whisky trade. As is usually the case when a daily newspaper takes up a subject of this kind, a number of well ‐ meaning people make a variety of suggestions as to what ought to be done to secure the purification of the particular Augean stable under discussion and to ensure the reception by the purchaser of the article which he really desires to have. But what ought to be done and what can be done are two very different things, and the question of what it is possible to do in the present state of scientific knowledge—and under the existing law as it is at present administered— is, as a rule, avoided by the writers referred to. It has been suggested, for instance, that it should be made compulsory that all vessels in which spirits are sold should bear a label distinctly stating the exact nature of the contents of such vessels. This would be an excellent suggestion if it could be effectively carried out, but, before this can be done, it is necessary to devise a method of compulsion. A man who sells as malt whisky an article mainly or entirely composed of spirit to which that title should not be applied would not have any very serious scruples as to the truth of the statements which appear on his labels. He must be compelled to act honestly by some sufficient force, and, short of a law which would permit the manufacture and “blending” of whisky to be carried out by certain persons only, according to specified rules, and under strict Government supervision in every case, no legislative enactments whatever would have the effect of preventing the various forms of this particular fraud. At present there are no legal definitions whereby the composition and characters of the articles described as “malt whisky” and “whisky” are laid down, excepting the definitions which may be held to be implied in the application of the 6th section of the Sale of Food and Drugs Act of 1875 to the case. This section requires that an article shall be of the “nature, substance, and quality demanded by the purchaser.” On the strength of this section it is quite unjustifiably assumed that the compulsion referred to can be effectively secured by the operation of the Sale of Food and Drugs Acts. According to our legal system it is essential under the criminal Acts— and the Food Adulteration Acts are criminal Acts—for the prosecuting authority to prove beyond all possibility of question that a person charged with an offence is guilty of that offence, and, in regard to the matter under consideration, it would therefore be necessary to absolutely prove by scientific evidence that any given mixed spirit, for the sale of which as malt whisky a prosecution had been instituted, was not of the nature, substance, and quality of the article demanded. Under the present conditions relating to sampling under the Acts this would be impracticable, except, possibly, on very broad lines; and, assuming that scientific investigation resulted in the possibility of fixing clear and definite points of distinction between the true and the false, there would still be the enormous difficulties and the heavy expenses attending the proving of offences of this character to the satisfaction of the Courts—difficulties and expenses which local authorities cannot fairly be expected to face. If, after the lengthy and expensive investigations that would be necessary, and which could only be properly carried out with Government aid, by a scientific Commission appointed by the Government, it were found possible to establish working definitions and standards, these would necessarily be only applicable to a limited extent, just as is at present the case in regard to milk and butter; while the question of quality can never be dealt with under repressive Acts of, Parliament of any kind. Assuming the establishment of standards of some kind we fully admit the possibility, under altered legal conditions, of checking the grosser forms of whisky sophistication by the employment of legal machinery, as is done with various other products; but vast amounts of various spirit mixtures could still be sold under false names with impunity. We should still have with us the legalised inferiority and the legalised adulteration of comparatively minor type which we have in the case of milk and butter. What is required and what alone can be effective, in dealing with sophistications which the law can never reach, is the provision of adequate and entirely independent guarantees which are based both on permanently‐applied analytical investigations carried out upon quantities of material which are not absurdly limited, and on a system of permanent and independent inspection,—both being supplied by some authority or authorities of sufficient standing. While the statements made by a reputable firm ought to carry weight, and ought, no doubt, to be accepted as valuable so far as they go, there is always necessarily and obviously a great element of weakness in the declarations put forward by a firm with respect to its own products. Particularly in view of modern commercial conditions something very much stronger than a personal asseveration as to the purity and excellence of one's own goods is now in reality required. That this is the case is shown by the fact that the demand for independent guarantees has recently been repeatedly voiced in the general press. The public are badly in want of education on all such questions and the Daily Telegraph is entitled to the thanks of the community for having initiated a discussion which can only be productive of good results in this direction.

Details

British Food Journal, vol. 5 no. 1
Type: Research Article
ISSN: 0007-070X

Article
Publication date: 1 March 1900

The Milk and Cream Standards Committee, of which Lord WENLOCK is Chairman, have commenced to take evidence, and at the outset have been met by the difficulty which must…

Abstract

The Milk and Cream Standards Committee, of which Lord WENLOCK is Chairman, have commenced to take evidence, and at the outset have been met by the difficulty which must necessarily attach to the fixing of a legal standard for most food products. The problem, which is applicable also to other food materials, is to fix a standard for milk, cream and butter which shall be fair and just both to the producer and the consumer. The variation in the composition of these and other food products is well known to be such that, while standards may be arrived at which will make for the protection of the public against the supply of grossly‐adulterated articles, standards which shall insure the supply of articles of good quality cannot possibly be established by legal enactments. If the Committee has not yet arrived at this conclusion we can safely predict that they will be compelled to do so. A legal standard must necessarily be the lowest which can possibly be established, in order to avoid doing injustice to producers and vendors. The labours of the Committee will no doubt have a good effect in certain directions, but they cannot result in affording protection and support to the vendor of superior products as against the vendor of inferior ones and as against the vendor of products which are brought down by adulteration to the lowest legal limits. Neither the labours of this committee nor of any similar committee appointed in the future can result in the establishment of standards which will give a guarantee to the consumer that he is receiving a product which has not been tampered with and which is of high, or even of fair, quality.

Details

British Food Journal, vol. 2 no. 3
Type: Research Article
ISSN: 0007-070X

Article
Publication date: 1 February 1903

The king's speech on the occasion of the opening of Parliament contained the announcement that further measures are to be proposed during the present Session for dealing with the…

Abstract

The king's speech on the occasion of the opening of Parliament contained the announcement that further measures are to be proposed during the present Session for dealing with the adulteration of dairy produce. It may be hoped that among other things this statement foreshadows an intention on the part of the Government to deal in some way with the drugging of milk and milk products—for the purpose of establishing somewhat more effective legal checks upon the abominable practice referred to than any which are at present applicable. As anything in the nature of comprehensive legislation appears to bo out of the question, we must be thankful for what we can get; and while many improvements in the law are required to enable other forms of sophistication and adulteration of dairy produce to be more effectively controlled, the amendment which is of primary importance is one which will take the direction indicated above, since the public health is directly and far more seriously affected by the ingestion of food containing “preservative” chemicals than by the use of merely impoverished or “faked” products—injurious and dangerous as some of these may nevertheless be particularly to infants and invalids.

Details

British Food Journal, vol. 5 no. 2
Type: Research Article
ISSN: 0007-070X

Article
Publication date: 30 November 2023

Dong Chen, Rui Zhang and JiaCheng Jiang

This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of…

Abstract

Purpose

This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of BiOBr/PVDF composite membranes made by adding different precursor ratios during the casting process.

Design/methodology/approach

In this paper, sodium bromide and Bi(NO3)3 were used as precursors for the preparation of BiOBr photocatalysts, and PVDF membranes were modified by using the phase conversion method in conjunction with the in situ deposition method to produce BiOBr/PVDF hydrophilic composite membranes with both membrane separation and photocatalytic capabilities.

Findings

The characterization results confirmed that the composites were successfully and homogeneously co-mingled in the PVDF membranes. The related performance of the composite membrane was tested, and it was found that the composite membrane with the optimal precursor incorporation ratio had good photocatalytic efficiency and antipollution ability; the removal efficiencies of methyl orange, rhodamine B and methylene blue were 80.43%, 85.02% and 86.94%, respectively, in 2.5 h. The photocatalytic efficiency of composite membranes with different precursor ratios increased and then decreased with the increase of the precursor addition ratio.

Originality/value

The composite membrane is prepared by phase conversion method with in situ deposition method, and the BiOBr material has unique advantages for the degradation of organic dyes. The comprehensive experimental data can be known that the composite membrane prepared in this paper has high degradation efficiency and good durability for organic dyes.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 4 July 2016

Jyoti Prakash and Vishnu P. Agrawal

Multiple attribute decision making (MADM) is a conceptual agenda used for evaluation and selection of optimal nanofluid to assure best performance of heat exchanger. Most of the…

Abstract

Purpose

Multiple attribute decision making (MADM) is a conceptual agenda used for evaluation and selection of optimal nanofluid to assure best performance of heat exchanger. Most of the studies focus on nanofluids focus on individual ability at one time. Relatively, not even a single study is available for selection of nanofluid for heat exchanger using concurrent design and MADM approach. The purpose of this paper is to propose a concurrent design methodology using MADM approach to assist improved design of heat exchanger concurrently for all the x-abilities in an integrated manner.

Design/methodology/approach

A combined methodology of applying MADM approach using concurrent design for x-abilities is called CE-MADM approach. Implementation of nanofluid to improve thermal performance of heat exchanger entails thorough evaluation of nanofluids in various x-abilities (performance, maintenance, thermophysical properties and modelisation) to make exhaustive management decision. Sensitivity analysis is also proposed to study the behaviour of height of variation of density, heat capacity, thermal expansion and thermal conductivity with varying particle volume fraction and variation of relative closeness of available alternates from ideally best possible solution.

Findings

MADM approach considering various x-abilities concurrently provide an approach for relative ranking of available nanofluids for optimum performance. Fishbone diagrams of all x-abilities are constructed to identify all the attributes and converge large number of attributes into single numerical index that are concurrently responsible for the cause thus saving time for easy evaluation, comparison and ranking by decision makers. Sensitivity analysis to demonstration height of variation of pertinent attributes with varying particle volume fraction. A MATLAB programming is established to execute calculations involved in the procedure.

Originality/value

This paper comprises a predictable and effective mathematical approach to improve design of heat exchanger with nanofluid bearing in mind all the required x-abilities concurrently. This combined approach of CE-MADM is never applied before in the field of nanofluid to predict best possible results in feasible conditions considering all the x-abilities. Sensitivity analysis is also presented from the assumed mathematical equations of thermophysical properties.

Details

Benchmarking: An International Journal, vol. 23 no. 5
Type: Research Article
ISSN: 1463-5771

Keywords

Article
Publication date: 1 February 1991

B.N. Ellis

This paper outlines the composition of water soluble fluxes for the electronics industry and their methods of use when wave soldering and reflowing tinned coatings and solder…

Abstract

This paper outlines the composition of water soluble fluxes for the electronics industry and their methods of use when wave soldering and reflowing tinned coatings and solder pastes. Process optimisation is facilitated by the Taguchi method. Three types of cleaning machinery are evoked, with varying results. It is shown that the energy/time relationship is important to ensure adequate cleaning quality. A number of fallacious arguments are debunked. Methods of water purification and the problems of effluent treatment for all sizes of installation are addressed. Doubt is expressed as to the viability of closed‐circuit water recycling except for the largest installations or where exceptional conditions prevail. It is shown that water soluble fluxes and their subsequent aqueous removal are unlikely to make any significant contribution to the Greenhouse Effect. The overall cost of their use is substantially similar to that of rosin fluxes with CFC‐113 azeotropes at 1986 prices. Cleanliness control under production and laboratory conditions is discussed with reference to both ionic contamination testing, including its use for SMDs, and SIR analysis, especially at low voltages, including non‐destructive production SIR testing. Reliability of the assembled circuits is shown to be at least as good as that with more traditional soldering and cleaning methods, frequently better, and this is the case even for military and aerospace applications. The paper concludes that, now that quality water soluble solder pastes are available, this method is most likely to become the workhorse for the majority of electronics applications.

Details

Soldering & Surface Mount Technology, vol. 3 no. 2
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 1 September 1913

My Lord, in this case, if you brush away—as I invite you to brush away—all the irrelevancies introduced by my friend, Mr. Hume‐Williams, I submit to you with confidence that this…

Abstract

My Lord, in this case, if you brush away—as I invite you to brush away—all the irrelevancies introduced by my friend, Mr. Hume‐Williams, I submit to you with confidence that this case is reasonably clear; but the elaborate argument he has delivered requires me, I am afraid, to repeat what I said in opening, that the only way to approach a case of this kind is to look at the Section of the Statute, and to see what the Section of the Statute was intended to prohibit. I am not going to trouble you with the earlier cases decided under the Food and Drugs Act. I know there have been decisions by the Divisional Court, but they cannot be looked to because the Act under which these proceedings were taken was avowedly intended to meet the difficulties that had arisen in the administration of the earlier Acts. The purpose of the Act is absolutely clear, especially in regard to Section 3, but let me remind you again that this Act contains several different offences, provided with appropriate defences, and guarded by certain specific conditions.

Details

British Food Journal, vol. 15 no. 9
Type: Research Article
ISSN: 0007-070X

Article
Publication date: 5 June 2017

Yuanpeng Cheng, Zili Li, Yalei Zhao, Yazhou Xu, Qianqian Liu and Yu Bai

The purpose of this paper was to investigate the corrosion behaviour of API X65 pipeline steel in the simulated CO2/oil/water emulsion using weight loss technique, potentiodynamic…

290

Abstract

Purpose

The purpose of this paper was to investigate the corrosion behaviour of API X65 pipeline steel in the simulated CO2/oil/water emulsion using weight loss technique, potentiodynamic polarization technique and characterization of the corroded surface techniques.

Design/methodology/approach

The weight loss analysis, electrochemical study and surface investigation were carried out on API X65 pipeline steel that had been immersed in the CO2/oil/water corrosive medium to understand the corrosion behaviour of gathering pipeline steel. The weight loss tests were carried out in a 3L autoclave, and effects of temperature, CO2 partial pressure, water cut and flow velocity on the CO2 corrosion rate of API X65 pipeline steel were studied. Electrochemical studies were carried out in a three-electrode electrochemical cell with the test temperature was 60°C, and the CO2 partial pressure was 1 atm by recording open circuit potential/time and potentiodynamic polarization characteristics. The surface and cross-sectional morphologies of corrosion product scales were characterized using scanning electron microscopy. The phases of corrosion product scales were investigated using X-ray diffraction.

Findings

The results showed that water cut was the main controlling factor of API X65 steel corrosion under the conditions of CO2/oil/water multiphase flow, and it had significant impact on corrosion morphology. In the case of higher water cut or pure water phase, general corrosion occurred on the steel surface. While water cut was below 70 per cent, corrosion morphology transformed into localized corrosion, crude oil decreased corrosion rate significantly and played a role of inhibitor. Crude oil hindered the corrosion scales from being dissolved by corrosive medium and changed dimension and accumulation pattern of the crystal grain, thickness and structure of the corrosion scales; thus, it influenced the corrosion rate. The primary corrosion product of API X65 steel was ferrous carbonate, which could act as a protective film at low water cut so that the corrosion rate can be reduced.

Originality/value

The results can be helpful in selecting the suitable corrosion inhibitors and targeted anti-corrosion measures for CO2/oil/water corrosive environment.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 17 August 2010

Liu Junyan, Han Rongdi and Wang Yang

Green machining is becoming increasingly more popular due to concern regarding the safety of the environment and human health. The important implementation of stricter…

Abstract

Purpose

Green machining is becoming increasingly more popular due to concern regarding the safety of the environment and human health. The important implementation of stricter Environmental Protection Agency regulations associated with the use of ample amount of coolants and lubricants has led to this study on a new green machining technology with application of water vapor as coolants and lubricants in cutting Ni‐based superalloys and titanium alloy Ti‐6Al‐4V with uncoated carbide inserts (ISO Type K10). The purpose of this paper is to show that machining technology with application of water vapour could be an economical and environmentally compatible lubrication technique for machining difficult‐cut‐materials.

Design/methodology/approach

In this paper, the effect of water vapor applications in machining difficult‐cut‐materials have been investigated in detail, the cutting force, the chip deformation coefficient, the rake face wear and the width of tool flank land VB have been examined and analyzed, and a new green cutting technology is researched to machining Ni base superalloys and Ti‐6Al‐4V difficult‐cut‐materials.

Findings

The cutting force of machining Ni base superalloys and Ti‐6Al‐4V was affected by direct water vapor application, being lower than dry cutting and wet machining for all machining conditions; the Λh is the smallest with applications of water vapor as coolants and lubricants compared to dry cutting, pure water and oil water emulsion conditions the tool life extended by about six times than dry cutting, about four times than oil water emulsions at low cutting speed (νc<100 m/min), and about two‐four times than dry cutting, about two‐three time than oil water emulsions at higher cutting speed (νc>100 m/min) during machining Ti‐6Al‐4V with application of water vapor direct into the cutting zone.

Originality/value

The green cutting technology which applies water vapor as coolants and lubricants advocates a new method for machining difficult‐cut‐materials (Ni base superalloys and Ti‐6Al‐4V) without any environment pollution and operator health problem because the cutting force and chip deformation coefficient are reduced, the tool life is extended, and the tool flank wear can be decreased with applications of water vapor as coolants and lubricants to alleviate the adhering and diffusion wear compared to wet cutting and dry cutting.

Details

Industrial Lubrication and Tribology, vol. 62 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

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