Purpose This study aims to fabricate and study the effect of five cumulative graphite (G) and graphite nanoplatelets (GNP) filler loading composites by polymerising PA6 precursor; monomer epsilon caprolactam with the two carbons in situ while taking cognisance of the mixing effects (simultaneous stirring and sonication at varying amplitudes and duration). Different aspect ratios will be used to model the two streams of polymerisations. Design/methodology/approach High viscosity extrusion grade PA6 and synthetic G of less than 2 µm particle size were used as fillers. GNP and G are dried for 6 h in vacuum oven at 90°C. Prior to in situ polymerisation, probe sonication was applied to disperse fillers in molten ɛ-caprolactam, the PA6 monomer. Five carbon loadings were made, that is 5–25 Wt.% for G and 0.5–2.5 Wt.% for GNP composites. Two different sonification regimes were applied 20% sonication amplitude for 20 min (20/20) and 40% sonication amplitude for 10 min (40/10). Findings Better tensile properties were achieved using the 20/20 processing streams for both G and GNP. The G- and the GNP-based composites systems of the 20/20 processing stream had tensile modulus and yield strength retained or improved above the unfilled PA6 value. The highest modulus obtained in the 20/20 streams are 1,878 and 1,201 MPa, respectively, for GNP and G at the highest loading levels, while the 40/10 processing streams had 963 and 1,247 MPa, respectively, for the GNP and G. Originality/value To the best of the authors’ knowledge, nobody has ever used sonification amplitude to compare mechanical properties.
Barite is barium sulfate with the chemical formula of BaSO 4. Unlike barite witherite (BaCO 3) it is not chemically inert, it can dissolve in water and, when dissolved, can cause an environmental hazard. Barite forms in many geologic environments with both metallic and nonmetallic minerals. Minerals associated with the ore are a main concern when mining and processing barite. In many barite deposits, silica is present,if the level of SiO 2 is high enough with prolong exposure to particle size of less 10 µm pose a health hazard, and the ore must be handled so as to reduce the respirable silica level. If unoxidized minerals such as pyrite are present with the barite, acidicrunoff could result from groundwater or storm water content. The runoff may also leach additional minerals from the ore, resulting in high minerals concentration. Both the runoff of this water as well as the accumulation of this water in mining pits is of possible environmental concern. These issues must be addressed within the context of the environmental requirements in place in the jurisdiction within which the mining occurs.This paper is aimed at characterizing Barite from Bukkuyum local government area of Zamfara state of Nigeria, using Empyrean diffractometer DY 674 (2010) for XRD phase analysis of the powdered sample. The peaks generated match those of a BaSO 4 in ICDD PDF 2 (2010) database. Minipal 4 energy dispersive X-ray Fluorescence (XRF) provided the elemental analysis in their oxides, with SiO 2 of 4.55% content and 19.5% of SO 3 that could be the source of silicosis and acidic runoff, respectively, that are of health and environmental concern. The SEM provided the photomicrograph picture with the fiber histogram giving the statistics of particle size of 2.19, 8.73 and 20.70µm, allwith the objective of giving adequate information of the environmental hazards associated with its exploration base on the findings of these characteristics.
Euphobia hirta (Eh) was subjected to elemental analysis using X-ray fluorescence (XRF), and the results revealed the following concentrations of the elements : sulphur (4.128 mg/kg), potassium (58.755 mg/ kg), calcium (34.102mg/kg), scandium (0.256mg/kg), titanium (0.348 mg/kg), iron (2.124 mg/mg), zinc (0.108 mg/kg), rubidium (0.040 mg/kg), strontium (0.089mg/kg), zireonium (0.026mg/kg), molybdenum (0.006 mg/kg) and thorium (0.120 mg/kg) respectively. All elements analysed above were within the permissible limit set by World Health Organization (WHO) and Food and Agricultural Organization (FAO).Vanadium, chromium, manganese, cobalt, nickel, copper, arsenic, selenium, palladium, silver, cadmium, tin, antimony, tellurium, caesium, barium, tungsten, gold, mercury and lead were not detected in the sample.Asian J. Med. Biol. Res. March 2018, 4(1): 49-54
LTE is the latest step in the telecommunication development. The expansion of LTE is largely due to the success of the high-speed packet access and the overgrowing need for capacity. A dual band microstrip patch array antenna for LTE applications in Malaysia has been proposed. Firstly, a single element antenna is designed to resonate at 1.8GHz and 2.6GHz, and the dimensions were calculated using transmission line model. Then, to achieve higher directivity, antenna arrays with two and four number of elements have been applied. A microstrip feed line with 3dB divider is used to feed each of the elements. Simulations are been carried out using CST Microwave Studio. Subsequently, simulation results are compared and analyzed. From the results, the 4 x 1 array antenna configuration has shown the best results with directivity of 11.2dB and 12.9dB at 1.8GHz and 2.6GHz respectively.
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