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The aim of this paper is to make lightweight high-performance concrete (LWHPC) with high economic performance from existing materials on the Algerian market. Concrete with high values with regard to following properties: mechanical, physical, rheological and durability. Because of the implementation of some basic scientific principles on the technology of LWHPC, this study is part of the valuation of local materials to manufacture LWHPC with several enhanced features such as mechanical, physical chemical, rheological and durability in the first place and with regard to the economic aspect in the second place.

The experimental study focused on the compatibility of cement/superplasticizer, the effect of water/cement ratio (W/C 0.22, 0.25, 0.30), the effect of replacing a part of cement by silica fume (8 per cent), the effect of combined replacement of a part of cement by silica fume (8 per cent) and natural pozzolan (10 per cent, 15 per cent, 25 per cent) and the effect of fraction of aggregate on properties of fresh and hardened concrete using the mix design method of the University of Sherbrooke, which is easy to realize and gives good results.

The results obtained allow to conclude that it is possible to manufacture LWHPC with good mechanical and physical properties in the authors’ town with available materials on the Algerian market. The mix design and manufacture of concrete with a compressive strength at 28 days reaching 56 MPa or more than 72 MPa is now possible in Biskra (Algeria), and it must no longer be used only in the experimental field. The addition of silica fume in concrete showed good strength development between the ages of 7 and 28 days depending on the mix design; concrete containing 8 per cent silica fume with a W/B (water/binder) of 0.25 has a compressive strength higher than other concretes, and concrete with silica fume is stronger than concrete without silica fume, so we can have concrete with a compressive strength of 62 MPa for W/C of 0.25 without silica fume. Then, one can avoid the use of silica fume to a resistance of concrete to the compressive strength of 62 MPa and a slump of 21 cm, as silica fume is the most expensive ingredient in the composition of the concrete and is very important economically. A main factor in producing high-strength concrete above 72 MPa is to use less reactive natural pozzolan (such as silica fume) in combination with silica fume and a W/B low of 0.25 and 0.30. The combination of silica fume and natural pozzolan in mixtures resulted in a very dense microstructure and low porosity and produced an enhanced permeability of concrete of high strength, as with resistance to the penetration of aggressive agents; thus, an economical concrete was obtained using this combination.

The study of the influence of cementitious materials on concrete strength gain was carried out. Other features of LWHPC such as creep, cracking, shrinkage, resistance to sulphate attack, corrosion resistance, fire resistance and durability should be also studied, because there are cases where another feature is most important for the designer or owner than the compressive strength at 28 days. Further studies should include a range of variables to change mixtures significantly and determine defined applications of LWHPC to produce more efficient and economical concretes. It is important to gather information on LWHPC to push forward the formulation of characteristics for pozzolan concrete for the building industry.

The LWHPC can be used to obtain high modules of elasticity and high durability in special structures such as marine structures, superstructures, parking, areas for aircraft/airplane runways, bridges, tunnels and industrial buildings (nuclear power stations).

The novel finding of the paper is the use of crystallized slag aggregates and natural pozzolan aggregates to obtain LWHPC.

The purpose of this paper is to investigate the microstructures, slag inclusions, morphology and composition of ancient Chinese iron coins exhumed from Emei Mountain and Baoji after 818‐966 years of being imbedded underground.

Metallography, scanning electron microscopy, energy dispersive spectrometry, X‐ray photoelectron spectrometry and Fourier transform infrared spectroscopy were employed.

The results showed that archaeological coins exhibited characteristics of a typical hypoeutectic white cast iron, with slag inclusions of FeS strips and phosphate. Porous or hexagonal platey corrosion products were discovered on the archaeological iron coin, which were mainly identified as Fe₂O₃, FeOOH, Fe_x(OH)_1−xCO₃ and Fe_x(OH)_1−xSO₄. The possible corrosion mechanisms for the iron coins were discussed based on the corrosion products.

This study revealed the characterization of corrosion products on archaeological iron coins and may provide guidance for the preservation of archaeological iron.

This paper aims to investigate the effect of delayed water curing on the mechanical and microstructural properties of fly ash-based geopolymer paste-blended with Ground Granulated Blast Furnace Slag (GGBS) with different rest periods.

The blended geopolymer paste was composed of GGBS (15 per cent of the total weight) and the base material, Fly Ash (FA). The blended mix was activated by activator solution (Sodium hydroxide and Sodium silicate) containing 6 per cent Na₂O of total base material. The effect of delayed water curing has been studied by gradually increasing the aging period (Rest Period) from 2 hours to 24 hours in the formation of activated outcome along with Calcium Silicate Hydrate (CSH). To analyze the mechanical and microstructural properties of the resultant blended geopolymer paste, compressive strength test, FESEM and XRD have been carried out. Moreover, a long-term durability test subjected to sulphate exposure has been performed to evaluate the durability of the designed sustainable geopolymer paste.

The present paper shows that the delayed water curing incorporates secondary heat input enhancing the partial polymer formation along with CSH. Slag-blended AAFA-based geopolymer paste is seen to exhibit quick setting property. Also, AAFA-based geopolymer paste samples subjected to longer rest period show early strength gain at a high rate under water curing as compared to those subjected to the shorter rest period.

To the best of authors’ knowledge, the effect of delayed water curing on the mechanical and microstructural properties of slag-blended AAFA-based geopolymer paste has not been studied before.

The study suggests that the high concentration of mining and metallurgical enterprises on the territory of the Russian Ural region determines the need to consider industrial waste, including nickel slag, as a possible raw material for the production of ceramic bricks. The article describes the properties of clays and nickel slag obtained at metallurgical enterprises in the Orenburg region and the features of their use as components in the composition of ceramic bricks.

To achieve this purpose, such tasks as determining the technological parameters of production, conducting the X-ray phase and microstructural analysis of the obtained samples were solved.

Compositions of ceramic mass using clay from the Khalilovsky deposit (Orenburg region) with the addition of nickel slag (20 and 40% by weight) have been developed, and their physical and mechanical properties (compressive strength, bending strength, water absorption and density) have been determined. With the help of modern research methods involving high-tech equipment, the microstructure is considered and the phase composition of the finished samples is determined. As a result of the conducted research, it was found that the composition of the selected clay and nickel slag in the obtained rational composition ensures the production of ceramic bricks of grades M175 and M200.

This is the first study on the use of nickel slag for the production of ceramic bricks. The results relate primarily to Russian feedstocks, but a methodology is presented that can be applied to other countries as well as to other silica-containing feedstocks.

This paper aims to the transportation of high concentration slurry through pipelines that will require thorough understanding of physical and rheological properties of slurry, as well as its hydraulic flow behavior. In spite of several contributions by the previous researchers, there is still a need to enrich the current understanding of hydraulic conveying through pipeline at various flow parameters. The pilot plant loop tests, particularly at high concentrations, are tedious, time-consuming and complex in nature. Therefore, in the current research the prediction methodology for slurry pipeline design based on rheological model of the slurry is used for calculation of pressure drop and other design parameters.

It has been established that slurry rheology plays important role in the prediction of pressure drop for laminar and turbulent flow of commercial slurries through pipeline. In the current research fly ash slurry at high concentration is chosen for rheological analysis. The effect of particle size and solid concentration is experimentally tested over the rheological behavior of slurry and based on the rheological data a correlation is developed for calculation of pressure drop in slurry pipeline.

The present study strongly supports the analytical approach of pressure drop prediction based on the rheological parameters obtained from the bench scale tests. The rheological properties are strongly influenced by particle size distribution (PSD), shear rate and solid mass concentration of the slurry samples. Pressure drop along the pipeline is highly influenced by flow velocity and solid concentration. The presence of coarser particles in the slurry samples also leads to high pressure drop along the pipeline. As the concentration of solid increase the shear stress and shear viscosity increase cause higher pressure drop.

The transportation of slurry in the pipeline is very complex as there are lot of factors that affect the flow behavior of slurry in pipelines. From the vast study of literature it is found that flow behavior of slurry changes with the change in parameters such as solids concentration, flow velocity, PSD, chemical additives and so on. Therefore, the accurate prediction of hydraulic parameter is very difficult. Different slurry samples behave differently depending upon their physical and rheological characteristics. So it is required to study each slurry samples individually that is time-consuming and costly.

Nowadays in the world, long distance slurry pipelines are used for the transportation of highly concentration slurries. Many researchers have carried out an experiment in the design aspects of hydraulic transportation system. Rheological characteristics of slurry also play crucial role in determining important parameters of hydraulic conveying such as head loss in commercial slurry pipeline. The current research is useful for the prediction of pressure drop based on rheological behavior of fly ash slurry at various solid concentrations. The current research is helpful for finding the effect of solid concentration and flow velocity on the flow behavior of slurry.

Slurry pipeline transportation has advantages over rail and road transportation because of low energy consumption, economical, less maintenance and eco-friendly nature. Presently majority of the thermal power plants in India and other parts of the world dispose of coal ash at low concentration (20 per cent by weight) to ash ponds using the slurry pipeline. Transporting solids in slurry pipelines at higher concentrations will require a thorough knowledge of pressure drop. In the current research a rheological model is proposed for prediction of pressure drop in the slurry pipeline, which is useful for optimization of flow parameters.

All the experimental work is done on fly ash slurry samples collect from the Jharli thermal power plant from Haryana State of India. Bench scale tests are performed in the water resource laboratory of IIT Delhi for physical and rheological analysis of slurry. It has been shown in the results that up to solid concentration of 50 per cent by mass all the samples behave as non-Newtonian and follows a Herschel–Bulkley model with shear thickening behavior. In the present research all the result outcomes are unique and original and does not copied from anywhere.

Proposes to treat social law contracts by covering the two most important aspects of the contract of employment, and also the collective agreement. Covers the contract of employment in full with all the integral laws explained as required, including its characteristics, written particulars, sources or regulations, with regard to employers, are also covered. Lengthy coverage of the collective agreement is also included, showing legal as well as moral (!) requirements, also included are cases in law that are covered in depth.

In an article entitled “Collective Bargaining — a theoretical analysis” A. Flanders defined collective bargaining as an “…institution for the joint regulation of labour management and labour markets.” The collective agreement, the result of the collective bargain, is normally an uninforceable contract and is a very different legal notion from that of the contract of employment. The function of the collective agreement is to regulate relations between the collective parties, that is between the employer's association or an individual employer, and a union or unions. Such relations are known as relations of a collective nature. They could include procedure agreements between the collective parties in relation to no‐strikes or other industrial action before the disputes procedure has been exhausted; matters to do with the structure of negotiations between the parties; the constitution of the bodies set up for collective bargaining purposes; procedures on re‐ negotiation of the collective agreement; and so on. The collective agreement has however another function, the individual function, which regulates relations between employer and employee. Terms and conditions of employment are usually regulated by the collective agreement. Thus pay scales, hours of work, holidays, wages during illness, overtime work, any matters relating to training, re‐training, apprenticeship, are some from among the numerous subjects to be found in conditions of employment. Procedures which relate to the individual employee, such as grievance and disciplinary procedures, may equally feature as part of the terms and conditions of employment which emanate from the collective agreement. Indeed statute requires that the employer gives his employee particulars of this latter's major terms and conditions of employment.

As yet there are no indications that the President of the Local Government Board intends to give the force of law to the recommendations submitted to him by the Departmental Committee appointed by the Board to inquire into the use of preservatives and colouring matters in food. It is earnestly to be hoped that at least some of the recommendations of the Committee will become law. It is in the highest degree objectionable that when a Committee of the kind has been appointed, and has carried out a long and difficult investigation, the recommendations which it finally makes should be treated with indifference and should not be acted upon. If effect should not be given to the views arrived at after the careful consideration given to the whole subject by the Committee, a very heavy responsibility would rest upon the Authorities, and it cannot but be admitted that the Committee ought never to have been appointed if it was not originally intended that its recommendations should be made legally effective. Every sensible person who takes the trouble to study the evidence and the report must come to the conclusion that the enforcement of the recommendations is urgently required upon health considerations alone, and must see that a long‐suffering public is entitled to receive rather more protection than the existing legal enactments can afford. To refrain from legalising the principal recommendations in the face of such evidence and of such a report would almost amount to criminal negligence and folly. We are well aware that the subject is not one that is easily “understanded of the people,” and that the complicated ignorance of various noisy persons who imagine that they have a right to hold opinions upon it is one of the stumbling blocks in the way of reform; but we believe that this ignorance is confined, in the main, to irresponsible individuals, and that the Government Authorities concerned are not going to provide the public with a painful exhibition of incapacity and inaction in connection with the matter. There is some satisfaction in knowing that although the recommendations have not yet passed into law, they can be used with powerful effect in any prosecutions for the offence of food‐drugging which the more enlightened Local Authorities may be willing to institute, since it can no longer be alleged that the question of preservatives is still “under the consideration” of the Departmental Committee, and since it cannot be contended that the recommendations made leave any room for doubt as to the Committee's conclusions.

Titanium dioxide pigments have been produced commercially for eight decades. The industry has seen many developments from the humble beginnings with uncoated, impure, anatase pigments to the highly refined TiO₂ pigments of today. For the past four decades there have been two commercial routes for making TiO₂ pigments ‐ sulphate and chloride. In recent years, significant efforts have been made to produce TiO₂ by both routes with greater environmental awareness. To compare the overall impact of TiO₂ manufacturing processes on the environment, life‐cycle assessments of several process options are described in this paper.

This paper aims to study the controlled release and synergistic effect of water-soluble polyvinyl alcohol (PVA) on phosphate corrosion inhibitor at the interface of thermal insulation cotton/carbon steel.

This study was carried out using a coating method, scanning electron microscopy, energy dispersive spectroscopy and AC impedance.

The single-phase phosphate particles were coated/adsorbed on the PVA film, which was formed on the fiber surface of corrosion inhibitor/PVA-impregnated rock wool sample. On the surface of Q235 steel, an effective protective film was formed by the corrosion inhibitor with partially dissolved PVA that can significantly increase the polarization resistance of corrosion reaction, and reduce the capacitive reactance of electric double layer. The rock wool impregnated with the phosphate corrosion inhibitor and 1.5 per cent PVA showed obvious controlled release and inhibition synergism.

The rock wool impregnated with the phosphate corrosion inhibitor and 1.5 per cent PVA showed the following advantages: the adsorption and release quantities of the corrosion inhibitor increased by 3.3 and 2.9 times, respectively; the release-adsorption equilibrium time increased from 2 to 6 h; and the corrosion inhibition efficiency increased from 61.55 per cent to 94.6 per cent.