Effect Of Chemical Additives Research Articles

Effect of chemical additives and recycled aggregate size on the properties of pervious concrete pavement

Effect of chemical additives and recycled aggregate size on the properties of pervious concrete pavement

Chemical Modification of Iron – Rich Beta Intermetallic Phase in Aluminium-Silicon Alloys: A Short Review

Iron-rich intermetallic phases normally form during solidification of aluminium – silicon alloys with low level of iron. This type of phases is known for creating a mechanical properties degradation, especially the beta intermetallic phase (β-Al9Fe2Si2). Various studies and researches have led to mitigate the harmful effect of these phases through physical separation, thermal treatment or microstructure alteration by chemical neutralization such as with Mn addition which changes their structure into cubic alpha phase (α-Al15(Fe,Mn)3Si2). In this paper, the effect of chemical addition was reviewed and discussed in terms of effectiveness of modifying the crystal structure or morphology of beta intermetallic phase

A Comparative Study of the Physico-Chemical Properties of Cement-Bonded Particle Boards from Semi-Pulped Bagasse and Newsprints

The objectives of this study were to compare the compatibility of semi-digested pulp and fully digested pulp with cement and to further determine how appropriate these two samples are for the production of outdoor particle boards using the hydration test to determine the compatibility through the compatibility factor obtained using the area ratio method. The effects of chemical additives on the compatibilities of the samples with cement and the existence of bond formation were also looked into. Stems of sugar cane were obtained from the Sabo market in Ile-Ife, Osun state, Nigeria while newspaper prints were also gathered from Obafemi Awolowo University, Ile-Ife, Nigeria. The samples were converted to mesh, bleached and then converted to pulp. Different tests comprising proximate analysis, phytochemical screening, compatibility test and hydration experiment. The results of physical tests showed that bagasse is light yellow in colour while the newsprint is yellow solid in colour. Phytochemical screening results indicated that saponins, alkaloids, and tannins were present in high concentration. Infrared analysis indicated the notable presence of hydroxyl, ester and carbonyl groups in the samples. Based on the compatibility values, the addition of additives such as CaCl₂ produced higher compatibility values. The study concluded that semi-pulped bagasse and the newsprints are appropriate for the production of the particle boards.

Effect of chemical additives on oil shale natural floatability

Abstract Improving the organic content in oil shale before retorting is a substantial target. The flotation process is proven as a good separation process for hydrophobic particles from their associated impurities. In this study, the natural floatability and the flotation with different types of reagents were investigated to show how effective these reagents are in improving their organic content (kerogen). Frothers such as pine oil and kerosene and collectors such as oleic oil and amine acetate were tested. The results indicated that the addition of any used reagent negatively affects the oil shale floatability. The descending order of flotation using chemical reagents, in terms of combustible grade and recovery, is natural floatability, with frothers, then with collectors. The grade and recovery of the naturally floated fraction are 18% and 92.7%, respectively, from 8.75% in the feed sample. The low dosage from either oleic acid or pine oil effectively reduced the grade and recovery to about 15% and 86%, respectively. Chemical reagents stand as barriers to particle–bubble attachment. The presence of higher dosages of frother leads to the agglomeration of the smaller organic particles, which leads to lower grades and recovery. While collectors play a significant role in increasing the flotation of inorganic particles rather than the organics.

Effect of chemical additives on concrete and reinforced concrete structures

Effect of chemical additives on concrete and reinforced concrete structures

Effects of Chemical Additives in Refolding Buffer on Recombinant Human BMP-2 Dimerization and the Bioactivity on SaOS-2 Osteoblasts.

Bone morphogenetic protein-2 (BMP-2) is a promising osteogenic agent in tissue engineering. BMP-2 is usually expressed in Escherichia coli owing to the high yield and low cost, but the protein is expressed as inclusion bodies. Thus, the bottleneck for BMP-2 production in E. coli is the refolding process. Here, we explored the effects of the refolding buffer composition on BMP-2 refolding. The BMP-2 inclusion body was solubilized in urea and subjected to refolding by the dilution method. Various additives were investigated to improve the BMP-2 refolding yield. Nonreducing SDS-PAGE showed that BMP-2 dimers, the presumably biologically active form, were detected at approximately 25 kDa. The highest yield of the BMP-2 dimers was observed in the refolding buffer that contained ionic detergents (sarkosyl and cetylpyridinium chloride) followed by zwitterionic and nonionic detergents (NDSB-195, NP-40, and Tween 80). In addition, sugars (glucose, sorbitol, and sucrose) in combination with anionic detergents (sodium dodecyl sulfate and sarkosyl) reduced BMP-2 oligomers and increased the BMP-2 dimer yield. Subsequently, the refolded BMP-2s were tested for their bioactivity using the alkaline phosphatase assay in osteogenic cells (SaOS-2), as well as the luciferase reporter assay and the calcium assays. The refolded BMP-2 showed the activities in the calcium deposition assay and the luciferase reporter assay but not in the alkaline phosphatase activity assay or the intracellular calcium assay even though the dimers were clearly detected. Therefore, the detection of the disulfide-linked dimeric BMP-2 in nonreducing SDS-PAGE is an inadequate proxy for the bioactivity of BMP-2.

Effects of chemical additives and mature compost on reducing nitrogen loss during food waste composting.

This study is aimed at adding different types of mature compost and sulfur powder, as additives into food waste composting to investigate the effect on nitrogen loss and compost maturity. The composting experiment used the in-vessel composting method and was conducted continuously for 15days. High-throughput sequencing was used to analyze the bacterial community during composting. Results showed that the secondary fermentation mature compost mixed with sulfur powder group had the most reduction of ammonia emission (56%) and the primary fermentation mature compost amendments were the most effective for nitrous oxide emission reduction (37%). The temperature, pH, and nitrogen forms of transformation of the pile significantly affect the nitrogen loss during composting. Firmicutes helped to promote the rapid warming of the pile, and Actinobacteria and Proteobacteria played an important role in decomposition of organic matter. Thermobifida and Ureibacillus had a main contribution to the rapid degradation of organic matter in the process of composting. The relative abundance of nitrogen-fixing bacteria was higher, and the relative abundance of predominantly ammonifying and denitrifying bacteria was lower than the control group, with the addition of different additives.

Effect of chemical additives on the consolidation behaviours of mini-PVD unit cells –from macro to micro

The mechanism of adding NaCl, CaCl2 and small amounts of cement/lime (1–4% by dry weight) into clay slurry for mitigating the effect of apparent clogging around PVDs during vacuum consolidation was investigated by mini-PVD unit cell consolidation tests as well as microstructure observations via scanning electron microscopy (SEM) imaging. The consolidation test results indicated that for the specimens with CaCl2, cement and lime additives the rate of consolidation increased considerably, while the effect of the NaCl additive was limited. The SEM images show that for the specimen without additive, there were obvious localized deformation-induced microstructure anisotropies. For specimens with CaCl2 and cement/lime additives, the microstructures of the soils tended to be isotropic. The additives tested reduced the thickness of the diffusive double layer around the clay particles and promoted the formation of a more stable flocculated microstructure, therefore mitigating the effect of apparent clogging.

The effectiveness of chemical additives on fermentation profiles, aerobic stability and in vitro ruminal digestibility of total mixed ration ensiled with Napier grass and wet distillers’ grains in southeast China

Chemical additives have been widely used to restrain the growth of undesirable microorganisms, and they were ideal additives to well preserve silages. The work aimed at evaluating the effects of four chemical additives on fermentation quality, aerobic stability and in vitro ruminal digestibility of the fermented total mixed ration (FTMR). The TMR was treated with: (1) no additive (control); (2) sodium diacetate; (3) calcium propionate; (4) sodium benzoate (SB); (5) potassium sorbate (PS) on a fresh weight (FW) basis. After 60 days of ensiling, the silos were opened and sampled to determine fermentation quality, in vitro rumen parameters, and then the 60-day FTMR were subjected to a 9-day aerobic stability test. Chemical additives significantly (p < 0.05) increased dry matter, crude protein, and water-soluble carbohydrates contents, and decreased ammonia nitrogen, ethanol contents, aerobic bacteria and yeast counts after 60 days of ensiling. During aerobic exposure, chemical additives obviously improved aerobic stability as indicated by higher lactic acid, water-soluble carbohydrates contents and lactic acid bacteria counts, and lower pH, ethanol, ammonia nitrogen contents, aerobic bacteria and yeast counts. Treatments with SB and PS had higher (p < 0.05) lactic acid content, and lower (p < 0.05) pH, ammonia nitrogen content, aerobic bacteria and yeast counts than other FTMR. After 72 h of incubation, chemical additives significantly (p < 0.05) increased cumulative gas production, in vitro digestibility of dry matter and crude protein. The SB and PS-treated FTMR had higher (p < 0.05) cumulative gas production and in vitro dry matter digestibility than other FTMR. These results indicated that SB and PS were more effective to improve aerobic stability and in vitro ruminal parameters, and they were recommended as optimal additives for FTMR. HIGHLIGHTS Four chemical additives were served as additives for fermentation total mixed ration Chemical additives markedly improved fermentation quality, aerobic stability and in vitro ruminal parameters Sodium benzoate and potassium sorbate were optimal for improving aerobic stability and in vitro parameters

Mechanical Behaviour, Properties and Characteristics of Foamed Cellular Concrete: A Review

Foamed cellular concrete (FCC) is a type of lightweight concrete. Traditionally, it has been used for insulation and void filling. However, in the last years, the possibility of obtaining high strength FCC has motivated the study of its structural use. The novelty and uniqueness of this article is to provide a review of the most important aspect of FCC including component materials, design and mix elaboration, physical properties and mainly, its mechanical behaviour. Also, in order to achieve a global understanding of the material and its characteristics, advances regarding its physical properties are collected: density, porosity, thermal, acoustic and water insulation, durability, fire resistance and drying shrinkage. Then mechanical properties such as elastic modulus, compressive, tensile, bending and shear behaviour, are analysed. The literature review also aims to evaluate the influence of using inert and active mineral additions, fibers and chemical additives to improve its mechanical and physical properties. Based on the work done, research needs have been identified: there are no prediction models for stress-strain behaviour with complete curves for FCC in compression nor in traction, the performed numerical modelling is scarce, use and effect of chemical additives is a not far studied, long-term tests are scarce or nil, the evaluation of resistance in different aggressive environments has not been sufficiently evaluated.

Effects of Chemical Additives on Rheological Properties of Dry Ground Ore - a Comparative Study

ABSTRACT It is well documented that chemical additives (grinding aid “GA”) during grinding can increase mill throughput, reduce water and energy consumption, narrow the particle size distribution of products, and improve material flowability. These advantages have been linked to their effects on the rheology, although there is a gap in understanding GA effectiveness mechanism on the flow properties. The present study aims to fill this gap using different GAs (Zalta™ GR20-587, Zalta™ VM1122, and sodium hydroxide) through batch grinding experiments of magnetite ore and addressing the mechanisms of their effects on the rheology by an FT4 Powder Rheometer as a unique system. Experimental results showed that GA improved grinding efficiency (energy consumption and product fineness), which were well-correlated with basic flow energy, specific energy, aerated basic flow energy, and aerated energy. Moreover, the rheometry measurement showed strong linear correlations between basic flow energy, specific energy, and the resulting work index when GAs was considered for grinding, which confirmed the effect of GA on ground particles’ flowability. Zalta™ VM1122, a polysaccharide-based grinding aid, showed the best performance with 38.8% reduction of basic flow energy, 20.4% reduction of specific energy, 24.6% reduction of aerated basic flow energy, and 38.3% reduction of aerated energy. It also showed the strongest correlation between the grinding parameters and flow parameters (r > 0.93). The present investigation shows a strong indication that the predominant mechanism of GAs is based on the alteration of rheological properties and identify Zalta™ VM1122 as the best GA.

Evaluation of the acute effects of chemical additives on the toxicity of a synthetic oilfield produced water

This study evaluated the acute effects of nine different production chemicals typically employed in oil exploration on the toxicity of a synthetic produced water (PW). Bioassays with the Microtox® System were performed to monitor changes in the level of light emission of the marine luminescent bacteria Vibrio fischeri during exposure to the samples. The results show that synthetic PW is moderately toxic to these organisms, and the addition of oilfield chemicals significantly increases its toxicity. For most of the additives tested, the toxicity of the aqueous phase following partitioning against crude oil was not strongly altered by the presence of these chemicals. Synergistic effects occurred in the three different mixtures investigated. Among the additives studied, biocide, corrosion inhibitor, H2S scavenger, and surfactant were the most toxic for V. fischeri. Furthermore, the surfactant has been identified as the possible source of the acute toxicity observed.

A comparative study on the effect of chemical additives on dry grinding of magnetite ore

Dry grinding as an alternative to wet grinding is one of Sweden's strategic research areas to promote dry beneficiation. However, dry grinding has remained unpopular due to its higher specific energy consumption (Ec), wider particle size distribution (PSD), difficult material handling, and purported effects on downstream processes. In this work, the effects of the new additives (Zalta™ GR20–587, Zalta™ VM1122, and Sodium hydroxide) employed as grinding aids (GA) on dry grinding and product characteristics of a magnetite ore were studied in light of possible downstream effects. The grinding efficiency of Magnetite increased after using GAs in comparison without the GAs; however, an optimal dosage exists for each of the chemical additives investigated. Comparing to grinding without GA, Zalta™ VM1122, a viscosity modifier was selected as the most effective GA where by using this GA; the Ec decreased by 31.1% from 18.0 to 12.4 kWh/t, the PSD became narrower and finer (the P80 decreasing from 181 to 142 µm), and the proportion of the particles (38–150 µm) increased from 52.5 to 58.3%. Zalta™ VM1122 resulted in increased surface roughness and minimum microstructural defects. Further, it was found that Zalta™ VM1122 resulted in similar zeta potentials and pH values for the product compared to grinding without GA. These comparable product properties are advantageous as they minimize any potential negative effects on all possible downstream processes such as flotation.

Effects of chemical additives on emissions of ammonia and greenhouse gas during sewage sludge composting

Chemical additives of magnesium chloride (MaC) and ferrous sulfate (FS) were investigated in sewage sludge composting. A treatment without chemical additive was used as the control group (CK). The effects of MaC and FS on ammonia (NH3) and greenhouse gases (CO2, N2O and CH4) emissions were evaluated. The results showed that the addition of MaC and FS promoted the degradation of organic matter and increased the ammonium concentration of the compost product. The maximum pH values decreased from 8.98 (CK) to 8.49 and 8.0 in MaC and FS treatments, respectively. In addition, the NH3 emission for the MaC and FS treatments reduced by 58.3 % and 82.9 %, respectively, whereas the methane (CH4) emission decreased by 22.9 % and 24.9 %, respectively. However, in FS treatment, the carbon dioxide (CO2) and nitrous oxide (N2O) emissions were higher than those in CK. Furthermore, the FS treatment exhibited lower germination index values (71.4 %) and higher electrical conductivity (6.62 mS/cm). Therefore, MaC is suggested as an additive for reducing greenhouse gas emission and conserving nitrogen during sewage sludge composting.

Effect of chemical additives on the construction - technical properties of concrete mixture

Effect of chemical additives on the construction - technical properties of concrete mixture

Experimental study of the effect of chemical additives on mechanical properties of foamed concrete

Experimental study of the effect of chemical additives on mechanical properties of foamed concrete

Effect of Chemical Additives in the Plating Bath on Surface Corrosion Resistance of Ni(P)

In this work, the effect of the chemical additives (surfactant, stabilizer) on the corrosion resistance of the Ni(P) layer was investigated. The average O content at the depth of 1 nm of the tested Ni(P) specimens was used as the indication of the corrosion degree for the tested Ni(P) specimen. The average O content at the depth of 1 nm of the tested Ni(P) specimens prepared with thiourea is 27.74 at.%, which is larger than the average O content (14.43 at.%) at the depth of 1 nm of the corrosion-tested Ni(P) layer. It can be concluded that the corrosion resistance of the Ni(P) layer would be greatly reduced two times with adding thiourea in the Ni(P) plating bath. The effect of the solder mask was also investigated on the corrosion resistance of the Ni(P) layer. We found that S impurities leaching from the solder mask might be co-deposited into Ni(P), and decrease the corrosion resistance of the Ni(P) layer. Yet, its influence is relatively lower than the effect of thiourea on the corrosion resistance of the Ni(P) layer. With adding CTAB, as a surfactant, in the Ni(P) plating bath, the average P content in the Ni(P) layer increases. The high P content further improves the corrosion resistance of the Ni(P) layer. Moreover, the positive effect of adding CTAB in the plating solution on the corrosion resistance of the Ni(P) layer would suppress the negative effect of the thiourea additive and solder mask in the plating solution. The main innovation finding of the work is that we found that adding CTAB in the Ni(P) plating solution can reduce the co-deposition of S impurities, from thiourea in the Ni(P) plating bath and the solder mask, in the Ni(P) layer. Consequently, the corrosion resistance of the Ni(P) layer can be further improved.

The Effect of Chemical Additives in Refolding of Recombinant Vascular Endothelial Growth Factor

The Effect of Chemical Additives in Refolding of Recombinant Vascular Endothelial Growth Factor

The effect of chemical additives in phosphoric acid anodization of aluminum-tantalum thin films

Biosensor development has relied on the process of anodization of sputtered aluminum‑tantalum thin films to develop specific optical properties for interference color generation. The anodization of thin sputtered films of aluminum (140 nm) on tantalum (230 nm) on silicon was completed in 0.4 M phosphoric acid under potentiostatic conditions (4 V) and with various additives: 0.1 M and 0.4 M citric acid, 3% (v/v) and 10% (v/v) of a commercial anodizing solution consisting of glycerol and glycolic acid, and 0.1 M and 0.4 M oxalic acid. The microstructural and optical properties of these films were analyzed using scanning electron microscopy, X-ray diffraction, and ellipsometry. The interference colors produced by the anodic aluminum and tantalum oxides on top of the tantalum metal layer were also observed. The addition of 0.1 M citric acid, 3% (v/v) glycerol and glycolic acid-based solution, and 0.1 or 0.4 M oxalic acid all produced changes to the porous microstructure of the anodic alumina, including lower roughness and more homogeneous surfaces by inhibition of the dissolution from phosphoric acid. Oxalic acid acted as the strongest inhibitor and significantly reduced surface roughness and pore size, increased the composite refractive index of the anodized film, and significantly changed the interference colors compared to films where no additive was used.

Effect of chemical additives on softness components of hygiene paper

Abstract Chemical additives are used singly or in combination to impart functionality to hygiene paper (suggested). In particular, in the hygiene paper making process, dry strength agent, wet strength agent, softener, and other are widely used. The effects of chemical additives on the softness components were evaluated. In the case of surface softness, there was no change in MMD according to the addition of dry and wet strength agents. The MMD (mean deviation from the average friction of coefficient) was decreased by adding a softener, which is the purpose of its addition to the hygiene paper making process. The softness and wet strength were improved when the wet strength agent was added before the softener. In addition, lotion treatment was applied to the surface of tissue paper. The surface softness component of non-silicone-based lotion was similar or improved, which may overcome the problems of silicon-based lotion.