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Sorption of Cr(VI), Cu(II) and Pb(II) by growing and non-growing cells of a bacterial consortium

Sannasi P, Kader J, Ismail BS, Salmijah S

Bioresour Technol, 2006 Mar;97(5):740-7.
PMID: 16324841

This paper reports the sorption of three metallic ions, namely Cr(VI), Cu(II) and Pb(II) in aqueous solution by a consortium culture (CC) comprising an acclimatised mixed bacterial culture collected from point and non-point sources. Metal sorption capability of growing and non-growing cells at initial pH of between 3 and 8 in the 1-100mg/L concentration range were studied based on Q(max) and K(f) values of the Langmuir and linearised Freundlich isotherm models, respectively. Maximal metal loading was generally observed to be dependent on the initial pH. Growing cells displayed significant maximal loading (Q(max)) for Pb(II) (238.09 mg/g) and Cu(II) (178.87 mg/g) at pH 6 and at pH 7 for Cr(VI) (90.91 mg/g) compared to non-growing cells (p < 0.05). At the pH range of 6-8, growing cells showed higher loading capacity compared to non-growing cells i.e. 38-52% for Cr, 17-28% for Cu and 3-17% for Pb. At lower metal concentrations and at more acidic pH (3-4) however, non-growing cells had higher metal loading capacity than growing cells. The metal sorption capacity for both populations were as follows: Pb(II) > Cu(II) > Cr(VI).

Matched MeSH terms: Metallurgy*
Dataset on optimization of EDM machining parameters by using central composite design

Soundhar A, Zubar HA, Sultan MTBHH, Kandasamy J

Data Brief, 2019 Apr;23:103671.
PMID: 30788395 DOI: 10.1016/j.dib.2019.01.019

Newly prepared titanium alloy (Ti-13Zr-13Nb (TZN)) using powder metallurgy is considered in this investigation. Titanium alloys (TZN) are used in hip and knee replacement for orthopedic implants. Conventional machining, TZN alloys produce higher tool wear rate and poor surface quality, but this can be reduced by Electrical Discharge Machining (EDM) method. Moreover, EDM produce good biological and corrosion resistant surface. In this research, experiments were conducted by considering the influential process factors such as pulse on time, pulse off time, voltage, and current. The experiments were designed based on Response Surface Methodology (RSM) of face centered central composite design. Analysis of Variance (ANOVA) was conducted to identify the significance process factors and their relation to output responses such as Electrode Wear Rate (EWR), Surface Roughness (SR) and Material Removal Rate (MRR). Further, an empirical model was developed by RSM in order to predict the output responses.

Matched MeSH terms: Metallurgy
The occurrence of oral-mucosal lesions among employees of a steelmill--a preliminary study

Zain RB, Koh LS

Dent J Malays, 1988 Nov;10(2):37-40.
PMID: 3271126

A study has been conducted on 198 employees of a steel-mill industry. These participants were examined for mucosal lesions in the oral cavity and including the commissures and vermillion borders of the lips. The prevalences of 16 types of lesions are reported.

Matched MeSH terms: Metallurgy
Lead contamination of the mining and smelting district in Mitrovica, Kosovo

Prathumratana L, Kim R, Kim KW

Environ Geochem Health, 2020 Mar;42(3):1033-1044.
PMID: 30206754 DOI: 10.1007/s10653-018-0186-9

Lead contamination in topsoil of the mining and smelting area of Mitrovica, Kosovo, was investigated for total concentrations and chemical fractions by sequential extraction analysis, mineralogical fractions by X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectrometer (SEM-EDX). The study revealed that all samples contained Pb exceeding USEPA standard of 400 mg kg-1. The highest total concentration of Pb (125,000 mg kg-1) was the soil from the former smelter. Sequential extraction results showed that the predominant form of Pb was associated with Fe-Mn oxide-bound fraction which ranged from 45.37 to 71.61% of total concentrations, while carbonate and silicate Pb-binding fractions were dominant when physical measurements (XRD and SEM-EDX) were applied. Application of Pb isotope ratios (206Pb/207Pb and 208Pb/206Pb), measured by inductively coupled plasma mass spectrometry, identified that Pb contamination is originated from similar anthropogenic source. The results reflected that the Pb contamination in the soil of this area is serious. In order to provide proper approaches on remediation and prevention of health impacts to the people in this area, a continuous monitoring and health risk assessment are recommended.

Matched MeSH terms: Metallurgy*
Radioactivity associated with amang upgrading plants

Hu SJ, Koo WK, Tan KL

Health Phys, 1984 Feb;46(2):452-5.
PMID: 6693279
Matched MeSH terms: Metallurgy*
Gamma radioactivity level in Sn slag dumps

Chong CS, Chong HY, Fun HK, Leong LS

Health Phys, 1985 Nov;49(5):1008-10.
PMID: 4066326
Matched MeSH terms: Metallurgy*
Radium-226 and 232Th concentration in amang

Hu SJ, Kandaiya S

Health Phys, 1985 Nov;49(5):1003-7.
PMID: 4066325
Matched MeSH terms: Metallurgy*
Fulltext Metal dust exposure and lung function deterioration among steel workers: an exposure-response relationship

Hamzah NA, Mohd Tamrin SB, Ismail NH

Int J Occup Environ Health, 2016 07;22(3):224-232.
PMID: 27392157 DOI: 10.1080/10773525.2016.1207040

BACKGROUND: Metallic dust is a heterogeneous substance with respiratory sensitizing properties. Its long term exposure adversely affected lung function, thus may cause acute or chronic respiratory diseases.
METHODS: A cross-sectional study was conducted in a steel factory in Terengganu, Malaysia to assess the metal dust exposure and its relationship to lung function values among 184 workers. Metal dust concentrations values (Co, Cr, and Ni) for each worker were collected using air personal sampling. Lung function values (FEV1, FVC, and %FEV1/FVC) were determined using spirometer.
RESULTS: Exposure to cobalt and chromium were 1-3 times higher than permissible exposure limit (PEL) while nickel was not exceeding the PEL. Cumulative of chromium was the predictor to all lung function values (FEV1, FVC, and %FEV1/FVC). Frequency of using mask was positively associated with FVC (Adj b = 0.263, P = 0.011) while past respiratory illnesses were negatively associated with %FEV1/FVC (Adj b = -1.452, P = 0.026). Only few workers (36.4%) were found to wear their masks all times during the working hours.
CONCLUSIONS: There was an exposure-response relationship of cumulative metal dust exposure with the deterioration of lung function values. Improvement of control measures as well as proper and efficient use or personal protection equipment while at work could help to protect the respiratory health of workers.

Matched MeSH terms: Metallurgy
Fulltext Study of anodised PM aluminium matrix composite reinforced with 15 wt % saffil™ alumina short fibre

Mohd Nazree Derman, Zainal Arifin Ahmad, Hussain, Luay Bakir, Nurulakmal Mohd Sharif

Journal of Nuclear and Related Technologies, 2007;2007(1):155-158.
MyJurnal

A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.

Matched MeSH terms: Metallurgy
Fulltext Production of titanium carbide by thermal explosion and TiC/Ti functionally graded materials (FGMS)

Rahbari, R., Hamdi, M., Farhudi, O., Yahya, R., Asmalina, M., Marzuki, Z.

Journal of Nuclear and Related Technologies, 2007;2007(1):233-242.
MyJurnal

Self-propagating high-temperature synthesis (SHS) of powder compacts is a novel processing technique being developed as a route for the production of engineering ceramics and other advanced materials. The process, which is also referred to as combustion synthesis, provides energy- and cost-saving advantages over the more conventional processing routes for these materials. In the case of titanium or titanium alloy materials, prior researches employed powder metallurgy technology for preparing metal matrix composites, MMCs and laminated structures through the use of fine powders of an inert phase or phases (TiC, TiN, TiB and TiB2B ) dispersed in Ti or Ti alloy powders. The present research relates to manufacture of titanium-ceramic composites that are synthesized by combustion synthesis (SHS) and retains a multilayered composite microstructure comprising one or more titanium-based layers and one ceramic titanium carbide layers.

Matched MeSH terms: Metallurgy
Fulltext Al/b4c composites with 5 and 10 wt% reinforcement content prepared by powder metallurgy

Yusof Abdullah, Mohd Reusmaazran Yusof, Azali Muhammad, Nadira Kamarudin, Paulus, Wilfred Sylvester, Nurazila Mat Zali, et al.

Journal of Nuclear and Related Technologies, 2012;2012(1):42-47.
MyJurnal

The preparation, physical and mechanical properties of Al/B4C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B4C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/B4C composites prepared by powder metallurgy was high.

Matched MeSH terms: Metallurgy
Fulltext The influence of depassivating element on the performance of aluminium anodes

Daud, M., Mohd Kamarudin, S.R., Samsu, Z., Ripin, M.S., Sattar, M.S., Rejab, R.

Journal of Nuclear and Related Technologies, 2013;2013(2):16-20.
MyJurnal

The corrosion behaviour of ternary aluminium alloy sacrificial anodes with small amount addition of tin as depassivating element in natural seawater was studied by means of conventional DC electrochemical measurements. Metallurgical microscope was employed in order to observe the changing of microstructure caused by tin present in ternary alloys. The relationship between microstructure and electrochemical results was examined and particular attention paid to the cause of the electrochemical efficiency of anode performance. The results indicate that the proper precipitates uniformly distributed of tin are influence on improving electrochemical performance of alumnium alloy anode.

Matched MeSH terms: Metallurgy
Fulltext A study of microstructure and hardness on Fe-Co/SiC composites

Noraziana Parimin, Linus, Andy

Journal of Nuclear and Related Technologies, 2009;2009(1):65-70.
MyJurnal

This research was conducted to study the effect of reinforcement particles on iron-cobalt (FeCo) composites. The composition of silicon carbide (SiC) was varied from 0 to 20 wt%. The composite was fabricated via powder metallurgy (PM) method, which consists of mixing, compaction and sintering processes. The powder was mixed for 2 hours to obtain uniformity between SiC and Fe-Co matrix and compacted to a cylindrical shape at 250 MPa. Samples were sintered for 2 hours at 900 o C with 10 o C/minute heating rate in argon atmosphere. The influences of reinforcement particle on the sintered samples were characterized in terms of microstructure and hardness testing. The Fe-Co/20wt%SiC composites show highest hardness value.

Matched MeSH terms: Metallurgy
Microbe-mediated sustainable bio-recovery of gold from low-grade precious solid waste: A microbiological overview

Rana S, Mishra P, Wahid ZA, Thakur S, Pant D, Singh L

J Environ Sci (China), 2020 Mar;89:47-64.
PMID: 31892401 DOI: 10.1016/j.jes.2019.09.023

In an era of electronics, recovering the precious metal such as gold from ever increasing piles of electronic-wastes and metal-ion infested soil has become one of the prime concerns for researchers worldwide. Biological mining is an attractive, economical and non-hazardous to recover gold from the low-grade auriferous ore containing waste or soil. This review represents the recent major biological gold retrieval methods used to bio-mine gold. The biomining methods discussed in this review include, bioleaching, bio-oxidation, bio-precipitation, bio-flotation, bio-flocculation, bio-sorption, bio-reduction, bio-electrometallurgical technologies and bioaccumulation. The mechanism of gold biorecovery by microbes is explained in detail to explore its intracellular mechanistic, which help it withstand high concentrations of gold without causing any fatal consequences. Major challenges and future opportunities associated with each method and how they will dictate the fate of gold bio-metallurgy from metal wastes or metal infested soil bioremediation in the coming future are also discussed. With the help of concurrent advancements in high-throughput technologies, the gold bio-exploratory methods will speed up our ways to ensure maximum gold retrieval out of such low-grade ores containing sources, while keeping the gold mining clean and more sustainable.

Matched MeSH terms: Metallurgy
Fulltext Palm oil derived trimethylolpropane triesters synthetic lubricants and usage in industrial metalworking fluid

Chang TS, Yunus R, Rashid U, Choong TS, Awang Biak DR, Syam AM

J Oleo Sci, 2015;64(2):143-51.
PMID: 25748374 DOI: 10.5650/jos.ess14162

Trimethylolpropane triesters are biodegradable synthetic lubricant base oil alternative to mineral oils, polyalphaolefins and diesters. These oils can be produced from trimethylolpropane (TMP) and fatty acid methyl esters via chemical or enzymatic catalyzed synthesis methods. In the present study, a commercial palm oil derived winter grade biodiesel (ME18) was evaluated as a viable and sustainable methyl ester source for the synthesis of high oleic trimethylolpropane triesters (HO-TMPTE). ME18 has fatty acid profile containing 86.8% oleic acid, 8.7% linoleic acid with the remaining minor concentration of palmitic acid, stearic acid and linolenic acid. It's high oleic property makes it superior to produce synthetic lubricant base oil that fulfills both the good low temperature property as well as good oxidative stability. The synthetic base oil produced had a viscosity of 44.3 mm(2)/s at 40°C meeting the needs for ISO 46 oils. It also exhibited an excellent viscosity index of 219 that is higher than some other commercial brands of trimethylolpropane trioleate. Properties of base oil such as cloud point, density, acid value, demulsibility and soap content were also examined. The oil was then used in the formulation of tapping oil and appraised in term of adaptability, stability and field test performance.

Matched MeSH terms: Metallurgy*
Flexibility and hardness of dental stainless steel wrought wires used in Thailand

Benjakul P, Cheunarrom C, Ongthiemsak C

J Oral Sci, 2001 Mar;43(1):15-9.
PMID: 11383631

Stainless steel wrought wires used as clasp arms for removable partial dentures in Thailand were compared with those used in some other countries (in the as-received condition) in terms of flexibility, Vickers microhardness and composition. The results showed that there were significant differences (P< or =0.05) among the wires. A Japanese stainless steel wire (SK) was obviously different from the others. It had the lowest proportional limit and microhardness, but its flexibility was almost the same. The chemical composition of each wire was not greatly different. The wires were about 18-20 wt% chromium and 8-9 wt% nickel, except for the SK wire, which had about 12 wt% nickel.

Matched MeSH terms: Metallurgy
Fulltext Fabrication and characterisation of aluminium boron carbide composites for neutron shielding

Yusof Abdullah, Mohd Reusmaazran Yusof, Nadira Kamarudin, Paulus, Wilfred Sylvester, Rusnah Mustaffa, Nurazila Mat Zali, et al.

Jurnal Sains Nuklear Malaysia, 2012;24(1):71-80.
MyJurnal

Al/B4C composites with 0 wt.%, 5 wt.% and 10 wt.% of B4C were prepared by powder metallurgy and their properties were characterised successfully. Investigation of the effect of milling times (4, 8, 12, 16 hours) on microstructure, phase identification, hardness and neutron attenuation coefficient of composites has been studied. The results showed that hardness increased with increased of milling time, with maximum hardness obtained at 16 hours milling time. The increment is slower as the composition of B4C increased. The hardness of Al/10%B4C, Al/5%B4C and Al/0%B4C were 81.7, 78.7 and 61.2 HRB respectively. Morphology of scanning electron microscopy (SEM) showed that microstructures play important role in controlling the hardness. Meanwhile, x-ray diffraction (XRD) analysis showed the phases and crystalline present in composites with an indication that crystalline of the grain increased as the milling time increased. Neutron absorption of Al/10%B4C composites showed that this composite has the highest attenuation coefficient, thus indicating that it is the best composites for neutron shielding.

Matched MeSH terms: Metallurgy
Fulltext Microstructural, Tribology and Corrosion Properties of Optimized Fe3O4-SiC Reinforced Aluminum Matrix Hybrid Nano Filler Composite Fabricated through Powder Metallurgy Method

Ashrafi N, Azmah Hanim MA, Sarraf M, Sulaiman S, Hong TS

Materials (Basel), 2020 Sep 15;13(18).
PMID: 32942621 DOI: 10.3390/ma13184090

Hybrid reinforcement's novel composite (Al-Fe3O4-SiC) via powder metallurgy method was successfully fabricated. In this study, the aim was to define the influence of SiC-Fe3O4 nanoparticles on microstructure, mechanical, tribology, and corrosion properties of the composite. Various researchers confirmed that aluminum matrix composite (AMC) is an excellent multifunctional lightweight material with remarkable properties. However, to improve the wear resistance in high-performance tribological application, hardening and developing corrosion resistance was needed; thus, an optimized hybrid reinforcement of particulates (SiC-Fe3O4) into an aluminum matrix was explored. Based on obtained results, the density and hardness were 2.69 g/cm3, 91 HV for Al-30Fe3O4-20SiC, after the sintering process. Coefficient of friction (COF) was decreased after adding Fe3O4 and SiC hybrid composite in tribology behaviors, and the lowest COF was 0.412 for Al-30Fe3O4-20SiC. The corrosion protection efficiency increased from 88.07%, 90.91%, and 99.83% for Al-30Fe3O4, Al-15Fe3O4-30SiC, and Al-30Fe3O4-20SiC samples, respectively. Hence, the addition of this reinforcement (Al-Fe3O4-SiC) to the composite shows a positive outcome toward corrosion resistance (lower corrosion rate), in order to increase the durability and life span of material during operation. The accomplished results indicated that, by increasing the weight percentage of SiC-Fe3O4, it had improved the mechanical properties, tribology, and corrosion resistance in aluminum matrix. After comparing all samples, we then selected Al-30Fe3O4-20SiC as an optimized composite.

Matched MeSH terms: Metallurgy
Effect of Milling Time on the Microstructure, Physical and Mechanical Properties of Al-Al₂O₃ Nanocomposite Synthesized by Ball Milling and Powder Metallurgy

Toozandehjani M, Matori KA, Ostovan F, Abdul Aziz S, Mamat MS

Materials (Basel), 2017 Oct 26;10(11).
PMID: 29072632 DOI: 10.3390/ma10111232

The effect of milling time on the morphology, microstructure, physical and mechanical properties of pure Al-5 wt % Al₂O₃ (Al-5Al₂O₃) has been investigated. Al-5Al₂O₃ nanocomposites were fabricated using ball milling in a powder metallurgy route. The increase in the milling time resulted in the homogenous dispersion of 5 wt % Al₂O₃ nanoparticles, the reduction of particle clustering, and the reduction of distances between the composite particles. The significant grain refining during milling was revealed which showed as a reduction of particle size resulting from longer milling time. X-Ray diffraction (XRD) analysis of the nanocomposite powders also showed that designated ball milling contributes to the crystalline refining and accumulation of internal stress due to induced severe plastic deformation of the particles. It can be argued that these morphological and microstructural variations of nanocomposite powders induced by designated ball milling time was found to contribute to an improvement in the density, densification, micro-hardness (HV), nano-hardness (HN), and Young's modulus (E) of Al-5Al₂O₃ nanocomposites. HV, HN, and E values of nanocomposites were increased by ~48%, 46%, and 40%, after 12 h of milling, respectively.

Matched MeSH terms: Metallurgy
Fulltext Nanomechanical Behavior of Multi-Walled Carbon Nanotubes Particulate Reinforced Aluminum Nanocomposites Prepared by Ball Milling

Ostovan F, Matori KA, Toozandehjani M, Oskoueian A, Yusoff HM, Yunus R, et al.

Materials (Basel), 2016 Feb 26;9(3).
PMID: 28773261 DOI: 10.3390/ma9030140

The nanomechanical properties of carbon nanotubes particulate-reinforced aluminum matrix nanocomposites (Al-CNTs) have been characterized using nanoindentation. Bulk nanocomposite specimens containing 2 wt % multiwalled CNTs (MWCNTs) were synthesized by a combination of ball milling and powder metallurgy route. It has been tried to understand the correlation between microstructural evolution particularly carbon nanotubes (CNTs) dispersion during milling and mechanical properties of Al-2 wt % nanocomposites. Maximum enhancement of +23% and +44% has been found in Young's modulus and hardness respectively, owing to well homogenous dispersion of CNTs within the aluminum matrix at longer milling time.

Matched MeSH terms: Metallurgy

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