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Article
Publication date: 1 September 1998

David Watt

Past and current uses of chemical treatments to control or eradicate fungal infections and/or insect infestations in buildings have led to a number of reported cases where…

Abstract

Past and current uses of chemical treatments to control or eradicate fungal infections and/or insect infestations in buildings have led to a number of reported cases where occupants and users of these buildings have suffered various physical symptoms. The role of chemical treatments, whether as biocides, fungicides, insecticides or wood preservatives, has therefore come under scrutiny and various countries are now reviewing their use in favour of a more benign approach to the management of decay in buildings. Growing concern for the environment and the health of those treating or living in treated buildings has also led to changes in the way we perceive and deal with buildings and building defects. As a result, the conventional approach to survey, defect diagnosis and remediation has to be re‐thought and placed in the context of a wider environmental agenda. This paper provides evidence for how historic chemical treatments can have effects on the health of the building and its occupants, and considers the implications of such treatments for those charged with specifying or undertaking works to the fabric of affected buildings.

Details

Structural Survey, vol. 16 no. 3
Type: Research Article
ISSN: 0263-080X

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Article
Publication date: 1 May 2002

Aysegul Tanik, Esra Ates Genceli and Alpaslan Ekdal

Chemical treatability of dairy wastewater originating from a dairy and dairy products plant at Istanbul was investigated on the basis of chemical oxygen demand (COD…

Abstract

Chemical treatability of dairy wastewater originating from a dairy and dairy products plant at Istanbul was investigated on the basis of chemical oxygen demand (COD) parameter as a pre‐treatment alternative. FeCl3, FeSO4 and alum were used as coagulants in the jar‐test experiments of four sets of daily composite wastewater samples taken once every month. The effect of acid cracking has also been searched through acid addition and pH adjustment. Characterisation studies demonstrated that wastewater characteristics varied within a wide range in spite of no significant production changes at the plant during the experimentation period. Optimum coagulant dosage has been determined as 200mg l–1 for all the coagulants with the optimum pH values between 4 and 4.5 for FeCl3 and FeSO4, and 5‐6 for alum. Maximum overall COD removal efficiencies were obtained as 72 per cent, 59 per cent and 54 per cent for FeCl3, FeSO4 and alum, respectively. Nevertheless, COD removal efficiencies were found to be inadequate to meet the current discharge standards of Greater Metropolitan Istanbul to sewer systems indicating that chemical treatment is insufficient for discharging chemically pre‐treated dairy wastewater to a sewage system, which was actually the main objective of the study. The results showed that the wastewater composition greatly influences the maximum removal efficiencies and also the conditions for optimum coagulation. However, attention to such chemical treatment studies on dairy wastewater has started to accelerate within the last decade in various countries of the world, such as United Arabic Emirates and Scandinavian countries where the targets of applying chemical treatment varied. In Scandinavian countries, biodegradable coagulants have been applied to use the sludge arising from the system for livestock feeding, leading to reuse of sludge. In Arabic Emirates, chemically treated dairy effluents are utilised for irrigation purposes. These recent studies point out that application of chemical treatment to dairy wastewater with various coagulants lead to a variety of utilities apart from being a pre‐treatment alternative.

Details

Environmental Management and Health, vol. 13 no. 2
Type: Research Article
ISSN: 0956-6163

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Article
Publication date: 25 October 2019

Alexandre Bevilacqua Leoneti, Danilo Vitorino dos Santos, Renato Santos da Silva, Alessandra Henriques Ferreira, Adriano César Pimenta and Sonia Valle Walter Borges de Oliveira

The purpose of this paper is to propose a process management framework for Chemical Waste Treatment Laboratories (CWTL) that can be used as a management tool to identify…

Abstract

Purpose

The purpose of this paper is to propose a process management framework for Chemical Waste Treatment Laboratories (CWTL) that can be used as a management tool to identify and manage critical process.

Design/methodology/approach

Proposition of a generic classification for categories of chemical waste; use of the ABC analysis as a tool for analysis of priority in relation to the inputs of an CWTL; use of the process matrix (variety vs volume) to identify the key resources required to perform the activities of a CWTL; and use of mapping process techniques to map the processes defined and calculate times.

Findings

The proposed framework was applied to a CWTL at University of São Paulo, Brazil, and showed that the high variability of demand is a significant factor in the management of this laboratory, requiring processes that are flexible to meet this demand. The results showed that the applicability of the production and operations management theories within the scope of process management of CWTLs, proved to be useful tools for improving the treatment efficiency of chemical waste in these facilities.

Originality/value

The novelty of this work is in the fact of using production and operations management tools in the management of CWTLs to propose diagnoses to improve the management of their processes. The proposition of a comprehensive classification for chemical wastes generated in CWTLs is also highlighted.

Details

Business Process Management Journal, vol. 26 no. 2
Type: Research Article
ISSN: 1463-7154

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Article
Publication date: 1 August 1996

Fayza A. Nasr and Hala M. El‐Kamah

Examines the treatability of highly polluted wastewater from a dairy factory prior to its final disposal into the public sewerage system. Physical treatment of the dairy…

Abstract

Examines the treatability of highly polluted wastewater from a dairy factory prior to its final disposal into the public sewerage system. Physical treatment of the dairy waste via aeration, followed by settling, resulted in a 25 per cent chemical oxygen demand (COD) reduction and elimination of odours. Chemical treatment achieved almost 50 per cent removal of COD. The chemical‐biological process using activated sludge/trickling filter resulted in 64 per cent and 90 per cent removal of the volatile organic matter value respectively. However, the quality of the waste produced does not meet with the National Regulatory Standards for wastewater disposal into the sewerage system. Chemical‐biological treatment using an upflow anaerobic reactor succeeded in reducing the pollutional parameters to coincide with the limits of the Egyptian Law 93/1962 and produces biogas as a source of energy at a rate of 0.39m3/kg COD removed.

Details

Environmental Management and Health, vol. 7 no. 3
Type: Research Article
ISSN: 0956-6163

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Article
Publication date: 19 June 2019

Vivek Kumar Tiwary, Arunkumar P., Anand S. Deshpande and Nikhil Rangaswamy

Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in…

Abstract

Purpose

Due to intrinsic limitations, fused deposition modelling (FDM) products suffer from the bad surface finish and inaccurate dimensional accuracies restricting its usage in many applications. Hence, there is a need for processing polymer patterns before, during and after their productions. This paper aims to highlight the importance of pre- and post-processing treatments on the FDM-based acrylonitrile butadiene styrene patterns improving its surface quality so, that it can be used in rapid investment casting process for making medical implants and other high precision components.

Design/methodology/approach

As a part of pre-processing treatment, the machine parameters affecting the surface quality were identified and optimised using design of experiments. The patterns developed after the first stage of optimisation were given different post-processing treatments, which included vapour smoothening, chemical treatment and sand paper polishing. The results were compared and the best ones were used for making patterns for making medical implants via rapid investment casting technique. The surface quality was checked while the dimensional changes happening during the stages of this hybrid technique were recorded using a three-dimensional optical scanner.

Findings

The surface roughness of the FDM based ABS patterns reduced from 21.63 to 14.40 µm with pre-processing treatments. Chemical treatment (post-processing treatment) turned to be the most suitable technique for reducing the surface roughness further down to 0.30 µm. Medical implants that used these pre- and post-processing treatments gave an average surface roughness of 0.68 µm. Cost and lead time comparisons showed that rapid investment casting technique can be a better method for low volume, customised and with specific requirements.

Originality/value

FDM parts/medical implants produced by rapid investment casting technique suffer from the inferior surface finish and inaccurate dimensional accuracies limiting its applications. A systematic approach to overcome this issue is presented in this research paper. This will directly help the end users and the manufacturers of medical implants, wherein, better surface finish and dimensionally accurate components are expected.

Details

Rapid Prototyping Journal, vol. 25 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Article
Publication date: 29 May 2019

Marjo Määttänen, Sari Asikainen, Taina Kamppuri, Elina Ilen, Kirsi Niinimäki, Marjaana Tanttu and Ali Harlin

While aiming to create methods for fibre recycling, the question of colours in waste textiles is also in focus; whether the colour should be kept or should be removed…

Abstract

Purpose

While aiming to create methods for fibre recycling, the question of colours in waste textiles is also in focus; whether the colour should be kept or should be removed while recycling textile fibre. More knowledge is needed for colour management in a circular economy approach.

Design/methodology/approach

The research included the use of different dye types in a cotton dyeing process, the process for decolourizing and the results. Two reactive dyes, two direct dyes and one vat dye were used in the study. Four chemical treatment sequences were used to evaluate colour removal from the dyed cotton fabrics, namely, HCE-A, HCE-P-A, HCE-Z-P-A and HCE-Y-A.

Findings

The objective was to evaluate how different chemical refining sequences remove colour from direct, reactive and vat dyed cotton fabrics, and how they influence the specific cellulose properties. Dyeing methods and the used refining sequences influence the degree of colour removal. The highest achieved final brightness of refined cotton materials were between 71 and 91 per cent ISO brightness, depending on the dyeing method used.

Research limitations/implications

Only cotton fibre and three different colour types were tested.

Practical implications

With cotton waste, it appears to be easier to remove the colour than to retain it, especially if the textile contains polyester residues, which are desired to be removed in the textile refining stage.

Originality/value

Colour management in the CE context is an important new track to study in the context of the increasing amount of textile waste used as a raw material.

Details

Research Journal of Textile and Apparel, vol. 23 no. 2
Type: Research Article
ISSN: 1560-6074

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Article
Publication date: 8 June 2012

Chiu‐Yin Kuan, Kay‐Hay Yuen and Min‐Tze Liong

This paper aims to investigate the physical, chemical and physicochemical characteristics of rice husk on alkaline treatment.

Abstract

Purpose

This paper aims to investigate the physical, chemical and physicochemical characteristics of rice husk on alkaline treatment.

Design/methodology/approach

Rice husk (RM) was alkaline treated to produce soluble (SR) and insoluble residues (IR). Each fraction was characterized and soluble fraction was used to produce nanofibres using electrospinning method.

Findings

Alkaline treatment was effective in isolating insoluble dietary fibre rich IR from the other interfering substances such as soluble dietary fibre, protein and lipids that originally present in RM and leached into SR. The problem of silica induced toxicity and indigestibility of rice husk was overcome by alkaline treatment. Alkaline treatment altered the inherent mineral content (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, zinc) of rice husk, and increased physicochemical properties such as emulsification ability and stability, water holding ability, mineral binding capacity (calcium, copper, iron, zinc), and antioxidant activity. SR had been successfully electrospun into nanofibres with the addition of polyvinyl alcohol.

Originality/value

The paper investigated the characteristic of rice husk (RM and IR) for the development of functional foods, pharmaceutical products and new bioactives delivery system at the expense of reducing environmental liability.

Details

British Food Journal, vol. 114 no. 6
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 20 November 2009

Teija Laine‐Ma, Pekka Ruuskanen, Satu Kortet and Mikko Karttunen

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of…

Abstract

Purpose

The adhesion between electroless copper and a substrate is one of the most important factors in the reliability of thermoplastic printed circuit boards. The purpose of this paper is to investigate the effects of mechanical grinding and acid etching of thermoplastic substrate materials on the adhesion of copper deposited by an electroless copper plating process. The base material of the test substrates was a new high temperature thermoplastic polyphenylene oxide (PPO) compound.

Design/methodology/approach

The effects of pre‐treatment on plastic surfaces are analyzed by the following methods: Fourier transform infrared (FTIR), SEM, the Dyne surface energy test and the surface roughness test. The adhesion between electroless copper and thermoplastic substrate is measured with a peel strength test.

Findings

The results showed that mechanical grinding of the substrates significantly increased adhesion but the highest adhesion is gained by using an acid etch treatment before electroless plating. These results indicated that adhesion between copper and the substrates was not directly proportional to the roughness and surface energy values.

Originality/value

The conventional sweller/desmear treatment used in a printed circuit board factory for pre‐treating epoxy based laminates prior to electroless plating is not suitable for these PPO compound boards. The copper adhesion is adequate when the substrates are etched with sulphuric acid/chromate solution. In that case the bonding between the metal layer and the plastic surface is stronger than the bondings between the polymer chains of the thermoplastic material. The adhesion mechanism of electroless copper in these mechanically abraded samples is mechanical interlocking of metal particles.

Details

Circuit World, vol. 35 no. 4
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 17 October 2017

Sergio Pietanza, Donato Sorgente and Gianluca Percoco

In this paper, the authors propose an experimental set-up to study the chemical vapour polishing technique confining pure dimethylketone atmosphere at a fixed temperature…

Abstract

Purpose

In this paper, the authors propose an experimental set-up to study the chemical vapour polishing technique confining pure dimethylketone atmosphere at a fixed temperature in a vacuum chamber. The purpose of this paper is to improve conventional vapour treatments lowering the amount of solvent, lowering time and temperature needed and improving the environmental impact of the technique.

Design/methodology/approach

A factorial design of experiments is adopted to understand the effect of the treatment on roughness and on the surface morphology of treated specimens.

Findings

The proposed method improves several aspects of well-known methods based on water–dimethylketone liquid solution such as: no interaction between water and workpiece and higher capability of process management. It also improves several aspects of well-known methods based on vapour, lowering the amount of solvent, time and temperature compared to conventional vapour treatments.

Originality/value

Chemical vapour polishing is a well-known technique for smoothing additive manufactured acrylonitrile butadiene styrene (ABS) parts. Several data and users' experiences are available on the Web about this topic. In recent scientific literature, a few papers are available about this topic, dealing with how process parameters affect the final surface roughness. In the present paper, the authors propose to improve the process performing the process using dimethylketone into a vacuum chamber. The main advantages are the significant reduction of the solvent needed to perform the process and lower time needed to obtain same results as atmospheric pressure treatments.

Details

Rapid Prototyping Journal, vol. 23 no. 6
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 August 1996

Hussein I. Abdel‐Shafy

Examines the fate of heavy metals in sewage water and the sludge produced. Investigates the level of metals before and after the use of chemical coagulants as well as…

Abstract

Examines the fate of heavy metals in sewage water and the sludge produced. Investigates the level of metals before and after the use of chemical coagulants as well as throughout every process of the plant. Results reveal that the present upgrading of the plant has a remarkable improvement in the performance of the sewage treatment. Concludes that such upgrading of the plant reduces sewage tax because of the improvement in performance. In addition, the hydrolysis of the pre‐treated sludge can improve the de‐nitrified process and therefore can save energy, while the application of lime can be a substitution for enlarging the plant itself.

Details

Environmental Management and Health, vol. 7 no. 3
Type: Research Article
ISSN: 0956-6163

Keywords

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