Papers by Keyword: Chemical Property

Abstract: There are abundant silica sand resources in Malaysia, however many have not yet been fully discovered. The primary component used in the production of glass is silica sand. The objective of this research was to determine whether local silica sand might be used to make coloured glass. The chemical composition and mineralogy of silica sand were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD), respectively. The physical properties such as particle size distribution were determined by using a mechanical shaker whereas grain morphology was identified by using a digital microscope. Additional equally significant properties such as moisture content, clay content, pH value and the specific gravity of silica sand were also measured by using standard laboratory testing method. The obtained results were compared to Malaysian Standard MS 701:2017, the standard specification for the production of coloured glass. From XRF analysis, the silica sand contained silicon dioxide at a concentration of 97.84%, alumina at 0.56%, iron oxide at 0.12% as well as several other oxides at around 1.5%. XRD diffractogram also revealed that quartz is a major constituent having the highest peaks at about 26.7° with an intensity of 13,7786. More than 95% of the particle sizes of the silica sand are in the size range from 150 µm to 1000 µm and in the category of fine sand and coarse sand. The grain shape was determined to be angular, and the silica sand had a moisture content of 2.54%, a clay content of 7.80%, a pH value of 5.93, and a specific gravity of 2.63. Based on the chemical and physical properties, it appears that this particular silica sand satisfies the standard requirements for coloured glass production.

Abstract: In order to discuss improving effect of ecological forest on heavy saline-alkali soil and to provide reference for biological improvement of saline-alkali soil, the soil chemical properties (pH, salt content, organic matter, available potassium and cation exchange capacity) of 20cm-depth in four different stages of growth on pure forest of Fraxinus velutina planted on heavy saline-alkali soil were studied. The results showed that pH value of forest soil in other stages of growth except defoliating stage was lower than that of CK, pH value in flowering stage decreased by 0.77 unit, and the decrease was the largest. The organic matter obviously increased in four different stages of growth, but the best effect of soil organic matter improvement was defoliating stage. During defoliating stage in mid-October, salt content of forest soil was 1/2 of CK, and cation exchange capacity was three point two nine times of CK. The available potassium of forest soil obviously increased in flowering stage and peak leafing stage. All in all, there was greater effect for the soil chemical properties of 20cm-depth in different growth stages of pure forest of Fraxinus velutina, so when salt-tolerance plant was used to improve saline-alkali soil, we should use scientific measure to cultivation and management in consideration of requirement of different growth stages of forest for soil water and soil nutrient in order to consolidate the improving achievements and to accelerate the improving process.

Abstract: Considering that the human being is in a universe where the population demand for consumer goods is rapidly growing, the United Nations (UN) concluded that the effective implementation of the use of renewable resources has a nearing deadline. As a result of population growth, a massive waste is generated, especially sewage, requiring adjustments in its disposal, treatment and final disposal. Based on this information, it must be highlighted that the generation of municipal waste due to the sewer, with a significant production of biogas and of sludge, presents major environmental problem due to their volume, size and features. This work points out that the ash of the wastewater sludge can have a more productive destination if used as an alternative material of construction. The research was divided into three stages. In the first stage, it was sample preparation sludge performed; in the second one, burning procedures were designed, and, in the third one, physical-chemical and mineralogical tests for the sewage sludge ash were made, seeking to assess the feasibility of using this residue in mortar and in concrete. According to the conducted studies, it was observed that there is a potential pozzolanic reactivity when using this material as a mineral admixture for Portland cement replacement.

Abstract: This research studied the effects of the water environment on the mechanical, chemical and morphological changes of environmental degradation polyethylene mulching film. The mechanical characteristics of the environmental degradation polyethylene mulching film immersed in water environment or exposed in air declined. The elongation at break retention of the sample immersed in water reached minimum value for 70 days while 40 days for sample exposed in air. FTIR showed new hydroxyl absorption band appeared at 1717cm^-1 after exposed for 60 days. The relative intensity of absorption band of sample exposed in air is higher than sample immersed in water. AFM images showed large fluctuation on the surface after immersed in water or exposed in air for 60days.

Abstract: Abstract. As there are serious wellbore instability problems in Yitong area, studying sloughing mechanism and anti-sloughing measures of the strata is of great importance, which differs significantly from the previous researches. Based on the international state-of-the-art, in this work several points are focused on which include the appearance characteristics of the cores, rock mineral composition and the shale physical and chemical properties. Sloughing mechanism is classified and anti-sloughing measures of the strata in Yitong area are proposed. When testing shale physical and chemical properties, several parameters are mainly tested and analyzed, including cation exchange capacity, specific water absorption, shale recovery rate and shale inflation rate. Five core samples are selected and collated data is reflected in tables in the experiment. It is worth mentioning that a new method of specific water absorption is adopted in the study to explain wellbore instability problems, which are caused by hydration. Limitations and shortcomings have been overcome by specific water absorption instead of total water absorption when evaluating water sensibility. The test shows satisfying and excellent results. After applying the anti-sloughing measures to the strata in Yitong area, sloughing accidents have been alleviated.

Abstract: A bench tests were carried out on an YC6J190 diesel engine fueled with B20 marine biodiesel. The results showed that the engine’s effective power decreased by 1.8%, the fuel consumption rate increased by 0.07%, HC emissions decreased by 19.17% and the soot decreased by 25% as average under full engine load conditions. HC decreased by 23.4% and the soot decreased by 23% as average under part engine load conditions. The soot emissions decreased by 28.8% as average under the free acceleration conditions.

Abstract: By deeply analyzing and studying the physical and chemical properties of Lueyang’s basalt fiber, its characteristics such as the chemical components, the crystallization’s upper limit temperature and lower limit temperature during the melting process, and the the viscosity and temperature change during melting process are verified to provide theoretical bases for the industrial production of a new type composite materials, and meanwhile to offer grounds for the development of a new generation of composite fiber materials.

Abstract: A typical kind of silicate gangue — sodium pyroxenite (mainly containing NaFeSi₂O₆) in Baiyunebo iron ore is selected as the research object in this paper. The endothermic peak and the change of quality is definited by means of thermal analysis (DSC and TG) in the rising process. And then the samples are sintered at the peak temperatures. The main ingredients of sodium pyroxenite and the resultants are definited by means of X-ray diffraction analysis (XRD). The experiment ascertains the change law of physical and chemical properties of sodium pyroxenite such as thermal decomposition, softening, melting temperatures and the corresponding resultants, which provides basic data for exploring the formation mechanism of complex calcium ferrite (SFCA) in baogang special sintered ore.

Abstract: The use of gypsum plaster for interior covering of walls and ceilings in the Portuguese architecture was particularly expressive in the period between the XVIII and the XX century. However, information about this important heritage is almost inexistent, which is leading to a fast loss of important patrimony. In this paper, the results of the characterization of gypsum plaster samples belonging to two buildings from the same historical period (end of the XIX century and beginning of the XX), situated in distant geographical regions of Portugal are presented and discussed. XRD, TGA-DTA, optical microscopy and SEM-EDS observations were used for the chemical and microstructural characterization. Some physical and mechanical properties, such as capillary absorption, dynamic elasticity modulus and compressive strength were also determined and a relationship between the characteristics observed in the samples and the technology associated to their use and application on site, as well as the possible existence of regional influences on all these aspects, are discussed.

Abstract: In the last years a new clinical method to carry out surgical operations has been introduced. It consists in minimally invasive vascular surgery (also called laparoscopy). In one hand, during laparoscopy procedures, sutures cannot be handled with fingers, and the use of stainless-steel needle holders is required. In the other hand, companies that fabricate sutures clearly mention that metal-made devices should be avoided when manipulating the monofilaments. Therefore, the manipulation of the suture monofilaments (made of polymers) by laparoscopic needle holders (made of metals) is controversial. Literature in this field is limited and incomplete. Therefore, the aim of this study was to investigate the mechanical and microstructural effects of the manipulations with laparoscopic needle holder on polymeric suture monofilament. Surgipro© (polypropylene), Teflene© (polyvinylidene fluoride) and Gore-Tex© (polytetrafluoroethylene) monofilament suture were pinched with a standard clinical protocol by a surgeon. Scanning electron microscopy, micro-mechanical testing, differential scanning calorimetry, x-ray diffraction, small angle x-ray scattering and Fourier transform infrared spectroscopy were then performed. Results showed that the ultimate tensile strength of Teflene and Gore-Tex sutures does not change after pinching whereas it decreases significantly for Surgipro sutures. This is attributed to stress concentration and to the compressive strength applied on the monofilament, which are closely related to the permanent deformation of the suture after pinching. Teflene and Gore-Tex monofilament sutures showed to be not affected even after severe pinching with laparoscopic needle holders. Therefore, our results clearly showed that the use of Surgipro II sutures in laparoscopic interventions should be avoided.