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This paper discusses the lower concentration reinforcement of cathodic ultrafine ceramic particulates, on metal matrices like Zn, Al and alloy‐matrices like Cu Zn, Cu Mn, Al Zn and Ni‐P‐B alloy‐electrodeposits, etc. It is assumed that these ultrafine ceramic particulates in lower concentration‐range are effective in covering the anodic grain‐boundary networks and other anodic‐defect sites, such that there is an effective reduction of surface anodic‐current. It is shown that at a critical threshold particulate concentration, the surface dissolution is minimum, followed by a drastic increase above that concentration. Such increase in dissolution is attributed to the random dispersion of the particulates on the grain‐proper, as these cannot be accommodated within the anodic grain‐boundary channels, micro‐voids and other defect sites. As such they form stress‐raiser points and enhance surface dissolution. This paper also discusses the correlation of the grain boundary structures, particulate trapping capacity of the matrix and the galvanic stress factors due to random distribution of particulates.

AA2014 is a copper-based alloy and is typically used for production of complex machined components, given its better machinability. The purpose of this paper was to study the effects of variation in weight percentage of ceramic Al₂O₃ particulates during electrical discharge machining (EDM) of stir cast AA2014 composites. Scanning electron microscopy (SEM) examination was carried out to study characteristics of EDMed surface of Al₂O₃/AA2014 composites.

The effect of machining parameters on performance measures during sinker EDM of stir cast Al₂O₃/AA2014 composites was examined by “one factor at a time” (OFAT) method. The stir cast samples were obtained by using three levels of weight percentage of Al₂O₃ particulates, i.e. 0 Wt.%, 10 Wt.% and 20 Wt.% with density 1.87 g/cc, 2.35 g/cc and 2.98 g/cc respectively. Machining parameters varied were peak current (1-30 amp), discharge voltage (30-100 V), pulse on time (15-300 µs) and pulse off time (15-450 µs) to study their influence on material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR).

MRR and SR decreased with an increase in weight percentage of ceramic Al₂O₃ particulates at the expense of TWR. This was attributed to increased microhardness for reinforced stir cast composites. However, microhardness of EDMed samples at fixed values of machining parameters, i.e. 9 amp current, 60 V voltage, 90 µs pulse off time and 90 µs pulse on time reduced by 58.34, 52.25 and 46.85 per cent for stir cast AA2014, 10 Wt.% Al₂O₃/AA2014 and 20 Wt.% Al₂O₃/AA2014, respectively. SEM and quantitative energy dispersive spectroscopy (EDS) analysis revealed ceramic Al₂O₃ particulate thermal spalling in 20 Wt.% Al₂O₃/AA2014 composite. This was because of increased particulate weight percentage leading to steep temperature gradients in between layers of base material and heat affected zone.

This work was an essential step to assess the machinability for material design of Al₂O₃ reinforced aluminium metal matrix composites (AMMCs). Experimental investigation on sinker EDM of high weight fraction of particulates in AA2014, i.e. 10 Wt.% Al₂O₃ and 20 Wt.% Al₂O₃, has not been reported in archival literature. The AMMCs were EDMed at variable peak currents, voltages, pulse on and pulse off times. The effects of process parameters on MRR, TWR and SR were analysed with comparisons made to show the effect of Al₂O₃ particulate contents.

A comprehensive field study of atmosphere coarse and fine particulate concentration was conducted in Jiddah, Saudi Arabia from September 1998 to April 2000. Coarse and fine particulate concentrations were investigated at five stations. The means coarse particulate concentration for 1998, 1999 and 2000 were 66mg/m³, 348mg/m³ and 192mg/m³ respectively. The corresponding means for fine particulate concentration for 1998, 1999, and 2000 were 10mg/m³, 69mg/m³ and 51mg/m³. Data reported in this paper provide emphasis with regard to the environmental and health impacts of inhalable coarse and fine particulates in the zone investigated.

A series of composite solders in 63/37 Sn/Pb was prepared: Cu₆ Sn₅ (10, 20, 30 wt%); Cu₃ Sn (10, 20, 30 wt%); Cu (7.6 wt%); Ag (4 wt%); and Ni (4 wt%). These composite solders were prepared by two procedures: (A) admixture with solder paste; and (B) admixture with molten solder. The original particulates and the final composite solders were analysed and characterised by SEM (scanning electron microscopy) EDX (energy dispersive X‐ray), and ESCA (electron spectroscopy for chemicals analysis); or XPS (X‐ray photoelectron spectroscopy). A variety of morphological characterisations, intermetallics and porosities were noted. Good wetting was noted in all cases, and porosity was greater for method (A). The particulates all exhibited excellent binding to the solder matrix.

This paper aims to study the effect of SiO₂ nano‐particulates on the corrosion behaviour of Ni‐W/SiO₂ nanocomposite coatings.

Weight loss measurements, electrochemical measurements and scanning electron microscope were used to study the corrosion behaviour of Ni‐W/SiO₂ nanocomposite coatings in NaCl solution.

The incorporation of SiO₂ nano‐particulates into the Ni‐W alloy matrix significantly increased the corrosion resistance. The improvement in corrosion resistance was due to the SiO₂ nano‐particulates acting as physical barriers to the corrosion process by filling in crevices, gaps and microscopic holes on the surface of the Ni‐W alloy.

This study highlights the use of nano‐particulates for the control of Ni‐W alloy coating corrosion and opens a new route for industry in the anti‐corrosion field.

In order to reduce the health impacts of air pollution effectively, developing strategies that involves individual or community level is crucial. The purpose of this paper is to assess people’s protective practices for inhalable particulate matter and its significant determinants such as general characteristics, knowledge and attitude among residents of an urban residential area, Dhaka, Bangladesh.

This cross-sectional study was conducted by systematic random sampling. A total of 424 people, who lived in that area for not less than two years before the survey, were interviewed using a structured questionnaire. χ² and Fisher’s exact test were used to analyze the data.

Only a small proportion of respondents had high practice level. In addition, a little more than half has high level of knowledge about inhalable particulate matter, its adverse health effects and protective practices and almost 70 percent had high level of attitude toward air pollution. The protective practices for small inhalable particulate matter was significantly associated with age, educational level, occupation, knowledge and attitude toward small inhalable particulate matter, its adverse health effects and protective measures.

A good level of knowledge about the prevailing air pollution and related health risks can be crucial to develop more focused attempt at changing the current situation with public participation. The environmental experts and health volunteer should disseminate precise and adequate information about long-term health hazards of particulate matter and measures of exposure prevention to improve the protective practices.

Discrete element method (DEM) has been extensively used in the laboratory of particulate and multiphase processing at the University of New South Wales (UNSW) to study the fundamentals of particulate matter at a particle scale. This paper briefly reviews the work in the laboratory, which covers the development of simulation techniques and their application to the study of particle packing and flow, transport properties and constitutive relationships of typical static or dynamic particulate systems. It is concluded, through representative comparison between simulated and measured results under different conditions, that DEM, as a major technique for discrete particle simulation, is an effective method for particle scale research of particulate matter.

The purpose of this paper is to present an optical technique for the condition monitoring of synthetic hydraulic oil; a deviation from the current techniques based on electrical principles which could be masked by wear particles and polar contaminants in oil.

Color‐change detecting device was developed using light‐emitting diodes, optic fibers and photodiodes of three‐color‐sensing elements. Color ratio (CR) and total contamination parameters based on transmitted light intensity in red, green, and blue wavelengths were used for oil chemical and particulate contamination assessment.

CR criterion was found independent of the particulate contamination of oil; but depended on chemical degradation. Total contamination index of the device depended on both the chemical degradation and particulate contamination of the oil, being most sensitive in blue wavelength, and least in the red. Test results for synthetic hydraulic oils monitored corroborated with results of viscosity, total acid number, RDE emission spectrometry, particulate counts and UV‐Vis photospectrometry. CR showed a clearer indication of oil degradation, compared to key monitoring parameters such as total acid number, viscosity, RDE emission spectrometry and particle counts.

This paper demonstrates how oil chemical degradation and total contamination could be detected through the device, before incipient wear occurs at tribological interfaces. The results showed that the color‐change parameters are effective criteria for the condition monitoring of synthetic hydraulic oils.

In this study, TiO2 is used to enhance the mechanical properties of the composite material containing agave Americana fiber and polyester resin.

Agave Americana fiber was first treated with 5% of NaOH, and the composition of treated and untreated fiber was kept constant, whereas the particulate and resin were alternatively used. The handlay method is used to fabricate the composite plates. The morphology of the composites was studied using scanning electron microscopy (SEM).

The composite was composed of 30% treated agave Americana, 10% of TiO₂ particulates and 60% of a polyester resin for better and enhanced mechanical properties.

The composite can be used for aero-structural components, automobile components and other areas where light-weight components are required.

A new type of agave Americana fiber with TiO₂ and polyester resin composite was fabricated and investigated.

The purpose of this study is to monitor suspended particulate matter (SPM), PM2.5 and source apportionment study for the identification of possible sources during the year 2018–2019 at Raipur, India.

Source apportionment study was performed using a multivariate receptor model, positive matrix factorization (PMFv5.0) with a view to identify the various possible sources of particulate matter in the area. Back-trajectory analysis was also performed using NOAA-HYSPLIT model to understand the origin and trans-boundary movement of air mass over the sampling location.

Daily average SPM and PM2.5 aerosols mass concentration was found to be 377.19 ± 157.24 µg/m³ and 126.39 ± 37.77 µg/m³ respectively. SPM and PM2.5 mass concentrations showed distinct seasonal cycle; SPM – (Winter ; 377.19 ±157.25 µg/m?) > (Summer; 283.57 ±93.18 µg/m?) > (Monsoon; 33.20 ±16.32 µg/m?) and PM2.5 – (Winter; 126.39±37.77 µg/m³) > (Summer; 75.92±12.28 µg/m³). Source apportionment model (PMF) have been applied and identified five major sources contributing the pollution; steel production and industry (68%), vehicular and re-suspended road dust (10.1%), heavy oil combustion (10.1%), tire wear and brake wear/abrasion (8%) and crustal/Earth crust (3.7%). Industrial activities have been identified as major contributing factor for air quality degradation in the region.

Chemical characterization of aerosols and identification of possible sources will be helpful in abatement of pollution and framing mitigating strategies. It will also help in standardization of global climate model.

The findings provide valuable results to be considered for controlling air pollution in the region.