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Aluminum composite or known as Aluminum Matrix Composite (AMC) that have good mechanical properties, example light weight, high toughness, high strength, and corrosion resistance. There are several potential applications for metal industries, like automotive part, aerospace, and transport vehicle. AMCs were just starting off at this point, with largely unproven and occasionally oversold properties. As a result, AMCs' reputation suffered, and other composite became more widely used, AMCs were largely forgotten. To reach some standard in design and manufacture, we need do enchantment or improving mechanical properties. In the other hand, quenching process can be chosen for affect mechanical properties of the aluminum composite. There are 3 variations of quenching agent, using water, oil, and salt solution (brine). Effect quenching process on aluminum matrix composite would increase mechanical properties but indicated distortion in various composite. This paper is extended to review other researcher related to effect quenching agent on the mechanical properties aluminum composite. [ABSTRACT FROM AUTHOR]

Tissue engineering is an area in which new tissues or organs are replicated in a promising way to replace damaged tissues or organs caused by accidents and medical conditions. For cells to grow, a proper environment provided by scaffolds can imitate the composition of that original human extra cellular matrix (ECM). This study focuses on the preparation of Polycaprolactone (PCL) nanofibers using electrospinning approach. The effect of process parameters such as PCL concentration, flow rate and voltage supply on the architecture of microstructure was also studied. The diameter and porosity of the nanofibers were analyzed from images taken by Scanning Electron Microscopy. Beads were found in the electrospun scaffolds due to high humidity. The beads formation was reduced by adding PBS salt solution and increasing the distance of the collector plate from the needle tip. Further, electrospun nanofibers with larger diameters were by having higher PCL concentration, higher flow rate and lower voltage. This study suggests the importance of the control of humidity and process parameters during process electrospinning in the control of the microstructure of the electrospun scaffolds. [ABSTRACT FROM AUTHOR]

This study investigated the corrosion behavior of metallic coatings consisting of Zn powder, which were deposited onto a low carbon steel substrate using the flame thermal spraying technique. Corrosion experiments were performed in salt water using a salty solution of 3.5 percent sodium chloride and one liter of filtered water to evaluate the coated layer's performance. Analysis of the test results enabled estimation of the rate of corrosion and investigation of the properties of the coated layer. Analyzing the test results made it possible to determine the corrosion rate and investigate the coated layer's characteristics. Effects on corrosion rates in the protective coatings layer were influenced by powder flow rate. The metallic coating's microstructure was investigated using SEM. It was discovered from the corrosion resistance and the polarization curves of the steel alloy coated layer that rising in salt solution led to higher corrosion resistance. The coating layer made of zinc powder displays strong corrosion resistance for low carbon steel. It is protected in a solution of 3.5 percent sodium chloride with a thickness of 103 microns, leading to good results. As a result, the coating layer's microstructure was consistent and homogenous, and there were no pores, which led to good corrosion resistance. [ABSTRACT FROM AUTHOR]

Chemical machining is one of the basic non-traditional machining methods, material removal is based on controlled corrosion. The selected chemical solution which is called etchant is employed to attack material in a corrosive environment. Ultrasonic-assisted chemical machining is a kind of hybrid machining method to increase the performance of the basic method. In this study, AZ31B magnesium alloy is machined by this method and the effects of selected chemical machining parameters (temperature and etchant type) on the surface roughness and depth of etch are investigated. Two different etchants (hydrochloric acid-HCl and nitric acid-HNO3) are used at two different chemical machining temperatures (25°c and 50°C). It was observed that ultrasonic-assisted chemical machining performed faster machining comparing to chemical machining. Moreover, HCl etchant accomplished better machining performance than HNO3 etchant as well as high process temperature (50°C) against low one (25°C). Surface finish results were better comparing to chemical machining process to ultrasonic-assisted chemical machining. [ABSTRACT FROM AUTHOR]

This study aims to determine the cause of scale formation in the T-115 oil well in the Tanjung Field and to provide a suitable chemical solution to prevent the same problem from occurring in other wells. Samples of scale and water formation were collected from the well and analyzed using x-ray diffraction (XRD), X-ray fluorescence, and cation and anion tests. Based on the results, the researchers designed a chemical solution to overcome the scale in the tubing. The implication of this study is to provide insights to the production team to prevent similar issues in other wells in the field and optimize production operations. [ABSTRACT FROM AUTHOR]

The effect of an aqueous solution of NaCl salt on the change in the dissociation of Freon hydrate over time at atmospheric pressure was studied experimentally. In the experiments, an aqueous salt solution with an initial concentration of 3% was used. For Freon hydrate synthesized in a salt solution, in contrast to the hydrate synthesized in pure water: 1) the degree of gas conversion in gas hydrate is 1.36 times higher; 2) the dissociation rate is 1.26 times lower. The research carried out is important for the further development of technologies for the synthesis, desalination and storage of gas hydrates. [ABSTRACT FROM AUTHOR]

The boiling of a layer of an aqueous NaCl salt solution with different initial salt concentrations on an aluminum surface was experimentally studied. The rate of water evaporation for most of the boiling time is 1.6-1.7 times higher than for a salt solution with an initial mass concentration of 20%. An increase in the salt concentration in a solution during boiling leads to a decrease in the number of bubbles formed during boiling. The key factors influencing the boiling process and the cessation of boiling of salt solutions are considered. [ABSTRACT FROM AUTHOR]

The effect of an aqueous solution of NaCl salt with hydrogen peroxide on the corrosion of grade A steel 414 Grade A was experimentally studied. Long-term corrosive exposure on the surface of the substrate led to a change in roughness by 5.3-5.4 times. After placing a drop of solution on the substrate after 60 s, the area Sd of the drop increases 2.3-2.5 times. This change in Sd is associated with the formation of hydroxyl groups and a change in the roughness of the substrate surface due to corrosion. There are II modes for changing the area of the corrosion spot Sc. The change in dSc/dt for mode II (120 < t < 300 s) is 1.36 times higher than for mode I (t<120 s). [ABSTRACT FROM AUTHOR]

Superabsorbent polymers, a three-dimensional cross-linked polymer, show excellent properties in retaining a large amount of water and have been widely applied in various fields. This report studied the synthesis of chitosan-strach superabsorbent by chemical crosslinking. The polymers were prepared by using 1:1 ratio of chitosan and starch in a concentration of 2% w/v with 2-25% v/v of glutaraldehyde as cross-linker. The characterization of chitosan-starch polymers was performed by using analytical tools, such as FTIR and SEM. Water absorption capacity was evaluated by swelling ability followed by the batch sorption of different 0.9% w/v salt solutions of NaCl, MgCl2, FeCl3 and synthetic urine composed of urea, NaCl, KCl, and Na3PO4. The biodegradation was evaluated by the difference mass of polymers before and after plantation in soil. The optimum polymers were obtained by using 5% of glutaraldehyde with water sorption capacity of 349.68%. The water absorbency capacity of different salts was 121.37%, 138.59%, and 165.20% for NaCl, MgCl2, FeCl3, respectively. The absorption capacity of SAP in synthetic urine, 1% w/v NaCl, 0.64% w/v Na3PO4, 0.6% w/v KCl, and 2.43% w/v urea solutions was 87.83%, 117.72%, 103,39%, 99.28%, and 91.08%, respectively. The degradation study indicated that the polymers were completely degraded in 14 days. [ABSTRACT FROM AUTHOR]

The aim of the research is to study the effect of the support material type and chemical solutions on the mechanical and physical properties of polymeric composites. Compounds based on the epoxy resin (Polymer-EP) were prepared by adding a hardener to Epoxy with a 2 (epoxy) to 1 (hardener) ratio, and various reinforcement materials were used, namely fibreglass, polyproline fibres, and silica oxide ceramic powder, with a micro-size (100mµ-50) for all models, and reinforcement material with a volumetric fraction (20%) was added, and the moulding method was used. Manual preparation of samples as follows: 1- Unreinforced Epoxy. 2- The overlay is reinforced with glass fibers (EP+F.G). 3- Overlay reinforced with Polypropylene fiber (EP+PP.F). 4- The composite is reinforced with silica powder (EP+SiO2). Thermal Expansion, Liquid Absorbency, and its effect on material properties were measured. Tap water and ethanol solution were used to mix the material. The results of the tests showed that the absorbency of the superimposed materials is higher than that of the unreinforced Epoxy, and its value varies according to the type of support material. [ABSTRACT FROM AUTHOR]

Basalt fibers and their products (fabrics, mesh, ropes etc.) are currently widely used as reinforcing elements in composites based on thermosetting plastics. Another possible application of basalt fibers lies in civil engineering where these fibers may be used in concrete as alternative to the conventional steel reinforcement. The basalt reinforcement can be realized in two ways: a) dispersed short basalt fibers (alternative to steel wires); b) basalt fiber reinforced plastic (BFRP) bars (alternative to steel rebars). As the "plastic" component, epoxy or vinyl ester resin is used. The primary driving force for replacement of steel reinforcing elements in concrete by another material (e.g. basalt fibers) is the steel sensitivity to electrochemical corrosion, which is frequently determining the lifetime of concrete structure. For the obvious reasons, basalt elements are not suffering from electrochemical corrosion, but it does not mean that they are completely corrosion-resistant. The present paper aims to contribute to the knowledge on corrosion behavior of BFRP bars in Simulated Sea Water (SSW). The experimental program consisted in exposing of BFRP bars to SSW and measurement of its tensile strength in time. It can be concluded that the strength controlling point is interlaminar shear of bars which is reduced by ongoing hydrolysis of epoxy resin during the bars exposure to Simulated Sea Water. [ABSTRACT FROM AUTHOR]

In the article, the analysis of the main problems of Metrological accounting of the world oil and gas industry, the quantity and quality of oil products, the main working wind of the Uzbekneftgaz network of the Mubarak oil and gas production department, the composition of the waters driving into the layer in oil production, the methodology for measuring the mass of nitrates in, requirements for measurement error, equipment pour safety requirements, methods for eliminating nnterferential effects, preparation of solutions necessary for analysis, preparation of a ferrotic salt solution with a mass fraction of 30%, preparation of a silver sulfate solution, preparation of an aluminum hydroxide suspension for coagulation, preparation of a sodium salicylate solution with a mass fraction of 0.5%, construction of a calibration graph, standards for monitoring the accuracy of, to control the accuracy of the measurement results, the results of the analysis obtained from the photometric measurement of the stratified waters released during the production process at the facilities of the Mubarak oil and gas production Administration under the territories of Bukhara region and Kashkadarya region are illuminated. [ABSTRACT FROM AUTHOR]

High voltage resistive divider made of salt solution has been designed, constructed and tested. This work develops a nanosecond pulse measurement system based on the NaCl solution resistive divider, which can be used to measure high voltage impulses with rise time of 5 ns and amplitude of 210 kV. The low voltage arm of the divider was built from radio carbon resistors, while the high voltage arm made from salt solution (NaCl in water) with different concentrations. The experimental results show that the measurement system has good response characteristics in the practical application. The divider is very simple, cheap and fast. [ABSTRACT FROM AUTHOR]

In this present study, effects of various input parameters on mechanical properties of Fused Deposition Modeling (FDM) components with and without electroplated Acrylonitrile Butadiene Styrene (ABS) samples have been reviewed. Several approaches have been taken into consideration to optimize these parameters. Therefore, it is considered that a review of the various approaches developed will support in comparing their mechanical properties, and allowing selection of the most appropriate approach for a give n application. Various parameters such as print orientation, infill density, layer thickness, tensile speed, and compression speed have a key impact in getting the greatest results of tensile, compressive, and flexural strengths. Variations in voltage, current density, dipping time, and chemical solution composition have all been found to have a significant impact on quality of electroplated surface. For effective layer coating on the substrate's surface, special attention must be paid on sharp edges and buried sections of the substrate. This research paper will give an insight about the effect of FDM machine control parameter on mechanical properties of the print components and selection of right parameters for printing of component for specific application. [ABSTRACT FROM AUTHOR]

The main factor for plant growth is fertilization. Fertilization is one of the important processes in plant growth that aims to add nutrients that are completely absorbed by plants. But excessive fertilization can damage the soil structure as well as plants become vulnerable to pests and wasting costs. However, until now, many farmers still apply fertilizer without knowing for sure the nutrient content of the soil; Meanwhile, checking the nutritional content of plants uses chemical solutions and sensors which are relatively expensive, making it difficult for farmers to implement. Based on this problem, this research aims to propose a new approach in the accuracy of fertilization based on soil pH sensors., by utilizing Internet of Things technology, this research focuses on providing recommendations for IoT-based fertilizers using soil pH sensors, the results of the sensors will be correlated with nutrients contained in the soil. Prediction of soil nutrient content is obtained from the correlation between plant environmental conditions. With this system, farmers can monitor the soil density around the plant and get fertilization recommendations through smartphones, and will get notifications of dosage recommendations and types of fertilizers if the pH condition is beyond the normal limit that has been determined. Based on the trials that have been carried out, the system can run well. [ABSTRACT FROM AUTHOR]

This study aims to develop and determine the effect of using mobile media Learning integrated Learning Management System (LMS) based on Discovery Learning on students' critical thinking skills on Ion Balance and pH of Salt Solutions. The research was carried out at SMA Negeri 92 Jakarta in December 2021 until April 2022. Method The research used is research and development by Borg and Gall with modify five Step, need analysis; development product; validation; testing product; and implementation. To see the influence of Mobile Learning media uses quantitative research with the Quasi Experiment method. The research design used was a nonequivalent control group design. In this study, 2 classes were used, namely class XI MIPA 4 as the experimental class and class XI MIPA 3 as the control class. Hypothesis testing using the Independent-Sample T test. The resulting media output is salt hydrolysis.apk with a file size of 78 MB which is compatible on android devices on smartphone nor tablets and salt hydrolysis.exe with a file size of 35.4 MB for laptop or PC use %. The posttest value of the experimental class was 74.88 while the posttest value of the control class was 69.15. Hypothesis testing on the posttest data obtained the value of Sig. (2-tailed) (0.01) < alpha (0.05) and Tcount (2.633) > TTable (2.024). It can be concluded that H0 rejected and H1 received which means there is influence significant use of Mobile Learning integrated Learning Management System (LMS) based on Discovery Learning on students' critical thinking skills on Ion Equilibrium and pH of Salt Solutions. [ABSTRACT FROM AUTHOR]

The degradation of reinforced concrete (RC) in aggressive environments is caused by a combination of factors ranging from force loading to weathering, to various chemical agents. Reinforcement corrosion in RC structures caused by excessive chloride ion diffusion is then one of the highly critical factors related to the potential destruction of this construction. Considering these facts, it is highly desirable to investigate the behaviour of concretes under a combination of force and chemical loading. The present study thus provides the basic results of an experiment in which laboratory concrete specimens were first subjected to partial loading in a press machine, then immersed in a fully saturated salt solution, and in the last step the compressive strength was determined. The loaded specimens were compared with specimens without the first loading and also with specimens immersed in normal water. This makes it possible to evaluate the combined effect. The results were evaluated also with respect to the strength increase under maturation of concrete in time. The results showed that concrete immersed in water after initial partial loading has a lower ultimate strength. Then, concrete without preloading force but immersed in chloride solution showed lower values and concrete preloaded and immersed in chloride for 90 days had the worst residual strength result. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC)is a biological fuel cells to treat wastewater and produce electrical energy from organic matter by using biological catalysts (mostly bacteria). The objectives of this research are to enhance the performance of tyre-derived rubber-microbial fuel cell (TDR-MFC) in treating domestic wastewater and to determine the efficiency of nutrients and energy recovery. Domestic wastewater was collected as the sample for this research. Then, tyre-derived rubber was prepared and cut into a specific dimension. After that, microalgal biofilm and salt solution were prepared. The microalgal biofilm was weighed and MFC was setup. The voltage of TDR-MFC was observed and recorded for every 20 minutes by using digital multimeter. The microalgal biofilm was weighed after completing one of the parameters for this research. Lastly, the resources recovery efficiencies were calculated. According to the results, the highest removal efficiencies of nitrogen, phosphorus and energy obtained in TDR-MFC with pH value of 6.5 were 3.60 %, 3.81 % and 4.106 % respectively. However, the highest removal efficiencies of nitrogen, phosphorus and energy obtained in TDR-MFC with glucose concentration of 10 g/L were 3.38 %, 3.99 % and 8.807 % respectively. In conclusion, TDR-MFC with pH value of 6.5 and glucose concentration of 10 g/L were showed the best performance in the nutrients and energy recovery. [ABSTRACT FROM AUTHOR]

Synthesis of heteronuclear complexes of Fe(III)-Mn(II)-Tartrate is reported here. The tartrate based heteronuclear complex was developed as functional material for catalytic applications and molecular magnets. Effect of type of Fe(III) salts and reaction temperature in the solvothermal synthesis of the targeted complex is also investigated. FeCl3 and (NH4)Fe(SO4)2 were used as the source of Fe(III) salts, in which the Fe(III) salt solutions were then mixed with solutions of MnCl2 and L−tartaric acid in a Fe(III)-Mn(II)-Tartrate mol ratio of 2:2:5 in a 50 mL of Teflon-autoclave. A mixture of dimethyl formamide and distilled water (1:3) was used as the solvent. The solvothermal reaction was done at 110 and 130 °C, respectively, for 2 hours. Solids that precipitated out from the reaction were separated by filter paper, dried in an oven, and then characterized by Fourier Transform Infrared (FTIR) spectroscopy, atomic absorption spectrophotometer (AAS), and powder XRD analysis. Experimental data shows that all four reactions resulted in identical pale yellow-greenish fine powder in different yields. FTIR analysis confirms the presence of tartrate ligand based on specific absorptions, namely a broad band around 3400 (O–H) cm−1, a sharp peak around 1650 (O–C=O) cm−1, and twin sharp peaks around 1400-1100 (C–OH) cm−1. Moreover, AAS confirms the presence of both Fe and Mn in all samples in a considerably significant amount. Powder XRD analyses confirmed that the synthesized complexes have identical crystal system. These results indicate that complexes of Fe(III)-Mn(II)-Tartrate were formed and the synthesis of the complex were not influenced by the type of Fe(III) salts or by the reaction temperature. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics possess polarization under stress and ferroelectric is a subcategory of piezoelectric which possess spontaneous polarization, phase transition, permittivity, electrical and optical characteristics beneficial for energy storage devices, capacitors, memories, sensors, generators and numerous other applications. Perovskite is the most important and appreciable class of ferroelectrics having structure 퐴퐵푂3. Here we described the structure, formation and application of some perovskites [e.g퐵푎푇푖푂3(BTO), 퐵푎(푆푟푥푇푖1−푥)푂3(BST), 푆푟푇푖푂3(STO), 푃푏푇푖푂3(PT), 푃푏(푍푟푥푇푖1−푥)푂3 (PZT)] which exhibits piezo, pyro and ferro-electricity. In this paper we will discuss the use of these perovskite structure in the fabrication of thin and thick film form by sol-gel synthesis, spin coating, chemical solution decomposition, sintering and milling utilized in detection of gas, light,humidity, temperature and pressure sensor-based application in detail. [ABSTRACT FROM AUTHOR]

In this article an attempt has been made to highlight the recent trends and advances in solution chemistry. Solvents and solvent mixtures have been found to be the backbone of solution chemistry and thermodynamic and transport phenomenon of different solvent systems have been recently much explored. The importance of solvents and solution chemistry lies in the fact that solvents are necessary and a pre-requisite in most chemical processes taking place in laboratory and industry. Recently, much explored area in solution chemistry is the structural aspect of the solvent in terms of molecular interactions as predicted from their thermodynamic and transport properties. These molecular interactions vary over a wide range such as hydrogen bonding, Vander Waal's forces, charge transfer, dipole-dipole and dipole-induced dipole interactions. As a consequence of these interactions, deviations occur from ideal behaviour. Therefore study of thermodynamic and transport properties of solutions extends the range of properties from which the structure of solution can be inferred. [ABSTRACT FROM AUTHOR]

Experimental studies on the effect of aqueous salt solution on the corrosion of the aluminum alloy during droplet evaporation have been carried out. Corrosion on a smooth surface will increase the evaporation rate. The evaporation rate is constant on the textured wall after laser surface treatment. The minimum corrosive current corresponds to a hydrophobic textured surface. Laser texturing on the surface of the aluminum alloy helps resist corrosion. This textured alloy can be effectively used in the power industry when exposed to high-temperature corrosive environments. [ABSTRACT FROM AUTHOR]

Keratin in chicken feathers has potential as a raw material for wood adhesives because it has functional groups from amino acid side chains that are able to cross-link with lignin in wood. The solid structure of keratin in chicken feathers needs to be converted into a soluble structure through a degradation step in order to be applied as a wood adhesive. Chemical degradation of keratin in chicken feathers cannot control the results of hydrolysis which causes keratin to be degraded into amino acids and produces hazardous chemical waste. Enzymatic degradation is an environmentally friendly alternative. Previous research reported that Bacillus sp. MD24 and 2 microbial isolates from Pasuruan salt pond water, namely TG3 and TG6 isolates were able to produce keratinase. Keratinase from each microbe is thought to have the ability to degrade by cutting at different specific keratin sites. Thus, the microbial consortium may be able to increase the concentration of soluble keratin hydrolyzate with more diverse molecular weights. This research was conducted with an experimental laboratory design. The steps carried out in this study include: (1) Confirming the ability of TG3 and TG6 isolates to produce keratinase; (2) Identification of TG3 and TG6 isolate species using 16s rRNA genomic methods; (3) Optimization of the humidity of the fermentation medium for TG3 and TG6 isolates; (4) Trial of microbial consortium isolates TG3 and TG6 with Bacillus sp. MD24 in keratinase fermentation. The environmental conditions of keratinase fermentation were carried out at 37°C and pH 8 using the Solid-State Fermentation method. TG3 and TG6 isolates have been tested for their ability to produce keratinase seen from their ability to degrade keratin in chicken feathers as much as 11.20% and 14.50% for 2 days of incubation, respectively. Species identification of isolates TG3 and TG6 showed that they were closely related to Salinivibrio proteolyticus with a similarity percentage of 99.13% and 99.14%, respectively. The optimization of the humidity of the fermentation medium showed that on the third day of incubation, both showed the highest optimum activity at variations in the ratio of chicken feather weight (g): volume of salt solution pH 8 (mL) 1:3. In this study, the microbial consortium of Bacillus sp MD24 with isolates TG3 and TG6 was not able to significantly increase the degradation ability of chicken feathers and the protein content of keratin hydrolyzate. This is possibly because the characteristics of the optimum pH and temperature of the enzymes produced by each microbe are different, so that in the microbial consortium it is necessary to select 2 isolates of microbes that have almost the same optimum characteristics of enzymes. [ABSTRACT FROM AUTHOR]

In this paper, the change in mechanical properties of natural composite materials (apricot kernel peels and vinylester) using two different weight fractions (30 and 60) by immersing them in chemical solutions was studied experimentally. Hydrochloric acid in concentrations (31, 15 and 10.32%) and brine (Marmara Sea water) in concentrations (23, 11.5 and 5.75%) were used for immersion composite samples. In the practical section, several samples of apricot kernel peels were made using vinylester and placed in hydrochloric acid and brine. Through tensile testing the mechanical properties were obtained. The results were a decrease in the ultimate stress and modulus of elasticity of (23, 17 and 10%) and (29, 22 and 16%) for the effect of hydrochloric acid (31, 15 and 10.32%) respectively. Also, reduce the ultimate stress and modulus of elasticity by (12, 7, and 4%) and (10, 6 and 3%) for the effect of brine (23, 11.5 and 5.75%) respectively. [ABSTRACT FROM AUTHOR]

In this research, the effect of chemical solutions on the mechanical properties of natural composite materials (eggshell with Vinylester) was studied experimentally. Three different weight fractions (30, and 60) were used. hydrochloric acid with concentrations (31, 15, and 10.32%) also, brine solution (Marmara Sea water) with concentrations (23, 11.5, and 5.75%)was used. In experimental work, many samples of eggshell with Vinylester with different weight fractions were manufacturing and placing it in hydrochloric acid and brine solution. Mechanical properties were found from tensile test. The result show that, decreasing in ultimate stress and modules of elasticity by (23, 17, and 10%) and (29, 22,and 16%) for effect of hydrochloric acid (31, 15, and 10.32%) respectively. Also, decreasing ultimate stress and modules of elasticity by (12, 7, and 4%) and (10, 6, and 3%) for effect of brine solution (23, 11.5, and 5.75%) respectively. [ABSTRACT FROM AUTHOR]

Separation processes using adsorbents and membranes can be regulated by incorporating stimuli-responsive materials. A wide range of polymers demonstrates changes in characteristics and performance reacted to an external stimulus including pH, temperature, gases, or pressure. Among the stimuli, CO2 is a nontoxic and abundant stimulus that can also be easily added or removed from the separation processes. In this paper, the progress of CO2 responsive adsorbents and membranes was studied. The tertiary amine or amidine groups of the CO2-responsive polymers could be easily protonated by CO2 bubbling, causing characteristic changes to regulate the separation. The synthesis, characteristics, and separation performance were examined. Poly(diethyl-amino-ethyl methacrylate) (PDEAEMA) modified microparticles were used to adsorb protein, but protein recovery remained unclear. The grafting of PDEAAMA and poly(2-(di-methylamino)ethyl methacrylate) (PDMAEMA) on microparticles allowed the adsorption of heavy metals, but higher recovery was attained by PDMAEMA modified microparticles under CO2 bubbling. The CO2-responsive polymeric microparticles were successfully applied in forward osmosis, producing water from salt solution without high temperature or pressure. PDEAEMA modified membranes were extensively studied in the separation of oil and water mixture due to their switchable surface hydrophilicity. PDEAEMA and PDMAEMA modified membranes were also tested in nanofiltration since they exhibited changes in pore size and zeta potential to control pollutant rejection. Nevertheless, CO2-responsive membranes could be cleaned under CO2/N2 bubbling. [ABSTRACT FROM AUTHOR]

Here we report for the first time to the best of our knowledge the synthesis of ultrathin calcite films by simple alternate dipping of pre-cleaned glass substrate in a calcium metal salt solution and a base solution. Deposited thin films were characterized by XRD, FESEM, FTIR and UV-Vis spectroscopy techniques. The XRD results confirmed the phase purity while depending on the number of dips either a micro/nano-brick morphology or a micro/nano flower morphology are noted in the microstructures studied by the FESEM technique. These results are discussed in terms of nucleation and growth of film on the substrate. Due to its non-toxic and biocompatible nature, these films can have applications in biosensors and photocatalysis. [ABSTRACT FROM AUTHOR]

The semi-automated cleaning-in-place (CIP) integrated cleaning technique is very common in food manufacturing companies. It consists of removing residues and cleaning equipment without the need to disassemble the production line. However, there have been problems with high pH levels after cleaning in the dairy company under study. This situation can represent the risk of contamination of the products with chemical agents used in cleaning and cause production delays. This research aims to improve the CIP process of the company. The Six Sigma methodology based on the DMAIC cycle was used. 70.1% of the problems related to CIP are non-compliance with the conductivity limits during the soda and acid stages. The data was collected directly from the software used in the company to monitor the activity, and the 33 cleanings carried out in the evaporator for 3 months were considered. The capacity analysis indicates problems of both variation and compliance with the objective, with values Cp=0.71 and Cpk=0.03 for the soda stage, and Cp=0.53 and Cpk=0.09 for the acid stage. Through multiple regression analysis and ANOVA, the root causes of the conductivity problem were found: the work shift, CIP cycle duration, temperature, outlet flow, and DSI pressure. The improvement proposals are mainly focused on establishing and monitoring standardized protocols for different tasks of the CIP, which include determining the concentration of chemical solutions, removing mud from caustic soda solution, and cleaning inside the tubes. It is estimated that these measures can reduce the problem by 33.5%. [ABSTRACT FROM AUTHOR]

Tetraethyl orthosilicate-methytriethoxysilane (TEOS-MTES) was successfully fabricated in this work to be applied in desalination. The aim of this work is to investigate xerogel deconvolution and membrane performance of TEOS-MTES under air and vacuum calcination for processing seawater salt solution (3.5% NaCl) via pervaporation. TEOS as silica precursor, nitric acid, and ammonia as dual acid-based catalysts were mixed by sol-gel process. The xerogels were calcined at 350 0C for 1 h under air and vacuum conditions, subsequently, xerogels were characterized via Fourier-Transform infrared spectrometer (FTIR). Fityk software was used to deconvolute the peak area in the FTIR. Whereas the membrane is dip-coated up to 4 times to be obtained 4 layers. The performance is tested through pervaporation at 25 °C feed temperature. Results show all MTES xerogels have carbon groups, silanol, and siloxane peaks. The organo-silica membrane water flux calcined under vacuum condition has almost 2-fold times higher than air calcination. Furthermore, all the TEOS-MTES showed about 99% of salt rejection. The membrane prepared under vacuum calcination has better performance than air calcination. [ABSTRACT FROM AUTHOR]

Keratinase plays an important role in the leather tanning industry. The industry requires enzymes that are stable in a high salt environment process. One source of those enzymes is microbes that live in salt ponds. Previously, 8 halophilic isolates were isolated from Pasuruan salt pond. TG-3 and TG-6 have been characterized and tested for their ability to produce keratinase using chicken feathers with the highest activity of 5.893 U/mL and 9.685 U/mL. In this study, TG-5 isolate was characterized and tested for its ability to produce keratinase. The results exhibited the TG-5 isolate was Gram- negative with a rode shape and was not a new type of microbe because the sensitivity to the Salinivibrio proteolyticus strain DV was above 97%, which was 99.20%, and it was called Salinivibrio proteolyticus TG5. The optimum activity of TG-5 keratinase was achieved at pH 8, temperature 43 °C, 5% NaCl, and the presence of 1 mM Mg2+ ions. Optimization of keratinase production by SSF method showed day 3 of incubation, at pH 7, and humidity ratio of 1:4 (chicken feather: salt solution) with enzyme activity value of 6.094 U/mL. The results indicate that salinivibrio proteolyticcus TG-5 has potential in tanning leather. [ABSTRACT FROM AUTHOR]

Inside Bedugul Tabanan Bali, Indonesia develops Stinging Nettle (Laportea bulbifera (Siebold & Zucc) Wedd) at altitude 1000 -1500 meters. Stinging nettle thrives and is abundant in the Bedugul area with the high tensile strength of the fiber. Nettle fiber has possible as a replacement for synthetic glass fiber used for composite reinforcement. Its advantages are in tensile strength, impact, and lightweight. The principle of this research was to clarify the impact strength of an epoxy composite reinforced with nettle fiber based on the fiber immersion treatment with a chemical solution with an impact test. This paper examines the effect of nettle fiber treatment on 5% NaOH solution and silane coupling agent at 3%, 6%, and 9% concentrations. Composite materials are produced by the hand lay-up molding method. The results showed that the highest impact strength value was 11.88 kJ/m2 at 6% silane, 30% fiber weight fraction. NaOH solution can remove impurities and lignin in the fiber. Nettle fiber treated with Silane coupling agent solution can form a strong bond in the matrix because it has removed the hydroxy group. Based going on the results of the research, it can remain concluded to the impact strength of the epoxy composite reinforced with nettle fiber has a higher impact strength in the 6% Silane treatment. Epoxy with nettle fiber has the potential to be applied as an Electric Battery Box. [ABSTRACT FROM AUTHOR]

This study aims to obtain a standard project-based chemistry practicum guidelines for XI grade natural science program students of senior high school on solubility and solubility product (Ksp) materials. The sample of population consisted of 3 chemistry practicum guideliness (publishers A, B, and C), 2 chemistry lecturers, 2 chemistry teachers, 2 classes of XI grade of natural science program. The research is descriptive, developmental and experimental by engaging ADDIE method. The results of standardization by teachers and lecturers on the A, B, C practicum guideliness, and the developed practicum guideliness obtained an average of 3.14, respectively; 3.32; 3.11; and 3.78. The practicum guidelines trial obtained by the experimental class was higher than control class (88.00% > 80.00%) and the activity value (performance) of the experimental class students was higher than the control class. Post-test data were analyzed by one-sided t-test at = 0.05, obtained t-count = 6.4 > t-table = 1.67. These results confirm that the project-based chemistry practicum guideliness that has been developed is good and meet the standard issued by BSNP (National Education Standard Board). Moreover, it is suitable to be used in learning chemistry at senior high school. [ABSTRACT FROM AUTHOR]

The use of learning media in addition to aids in learning, but also can increase student interest in learning. As a science student, one of the learning media used in Basic Chemistry courses is chemicals in labeled bottles. To add to the innovation of existing learning media with technological developments, a learning media development was made in the form of a reagent bottle containing chemicals labeled with a QR Code which when scanned can display information about the chemicals in it. This research is research and development. The stages carried out are analysis, design, development and evaluation. Perform a validation test of material, media and readability experts to users, namely science students. The resulting product is a reagent bottle filled with chemicals (acids and bases) labeled with a QR Code and installed on a smartphone called Bottle Chem. The results of the material, media and readability validation tests were 95.83%, 96.5% and 90.5%, respectively. The post-test results were 18.2 higher than the pre-test. It can be used that the Chemical Bottle media is declared very feasible and very good in Basic Chemistry lectures. Then also this product is able to increase students' knowledge. It is hoped that the media effectiveness test and similar development will be carried out on other chemicals. [ABSTRACT FROM AUTHOR]

This study aimed to identify students' understanding and misconceptions about the acid-base properties of salt solution. A valid and reliable four-tier instrument was employed. This study involved two groups of students from two secondary schools in the Regency of Banyuwangi, East Java. The study revealed that students' understanding of the topic falls in the low category. In addition, several misconceptions were also revealed, including (1) salt derived from a weak acid and weak base don't hydrolyze, (2) salt derived from a strong acid and strong base hydrolyze, (3) neutral salt is produced due to the same number of the cation and anion in the solution [ABSTRACT FROM AUTHOR]

This study aimed to develop an instrument for assessing high school students' ill-structured problem-solving skills using local socio-scientific issues (SSI) for the topic of solution chemistry. The development of the instrument consisted of 4 stages: (1) preliminary study, (2) item development, (3) expert judgment, and (4) tryout. The research subject for the tryout included 68 senior high school students (16-18 years old). The instrument entailed 45 items and 5 ill- structured problem texts integrated using local SSI on the topic of solutions chemistry (e.g., solution concentration, acid- base neutralization reaction, weak acid-base ionization equilibrium, and the principle of buffer solution in human blood). The integrated local SSI context consisted of environmental issues (e.g., textile industry waste, acid mine drainage, fish feed residue due to floating net cages, and coal power plants emissions) and society-health concerns (the pros and cons of alkaline water). Each ill-structured problem consisted of 9 questions (7 multiple-choice and 2 essay questions) based on 4 stages of the ill-structured problem-solving process, i.e., (1) problem representation, (2) generating and selecting solutions, (3) making justifications, and (4) monitoring and evaluating solutions. The expert judgment was carried out by a chemistry educator and two experienced chemistry teachers. The results indicated that the instrument is very feasible. The stage of tryout in this study aimed to examine the readability, item difficulty index, and reliability of the instrument. The tryout results stated that the students' ill-structured problem-solving instrument has very high reliability (Cronbach's Alpha coefficient=0.878). Therefore, the instrument developed in this study can be employed as an assessment tool to improve students' skills in solving ill-structured problems encountered in their daily life for achieving their scientific literacy. [ABSTRACT FROM AUTHOR]

This study aims to develop a four-tier assessment that is used to detect student misconceptions about salt hydrolysis. This type of research is development research using a 4D model (define, design, develop, disseminate). The sample in this study were 3 expert validators to test the feasibility of the assessment and 10 students for small class trials. Based on the results of the study, it was shown that from the feasibility test of the assessment by 3 expert validators, an average of 4.2 was obtained with the category suitable for use. Assessment trials in small classes show that the highest misconception is in the indicator of analyzing salt compounds that are in accordance with the experimental results, namely 60% of students, calculating the pH of salt solutions from strong bases and weak acids by 50% of students, determine salt compounds based on the pH value of 50% of students, analyze mixtures that undergo partial hydrolysis and are acidic by 50% of students and 50% of students who have misconceptions on indicators analyze the reaction equation of hydrolysis of acidic salts. The developed four-tier assessment can be used to detect students' misconceptions about the salt hydrolysis material. [ABSTRACT FROM AUTHOR]

The chocolate is one of the most popular foods all over the world, representing a highly nutritious source of energy. In this paper is proposed a way to improve the antioxidant function of chocolate by rosehip powder incorporation in the recipe. Additionally, a part of cocoa from its manufacturing recipe was replaced by carob powder. Rosehip powder brings along a high intake of vitamin C, B1, B2, K, carotenoids, pectin, carbohydrates, and also organic acids. Due to the high level of vitamin content, it is recommended the rosehips consumption in various forms. Carob flour has shown nutritional properties much better than those of cocoa, being an alternative ingredient mainly recommended in the children's nourishment because the carob powder does not stimulate gastric acidity, has a very high antioxidant and contains no gluten or lactose. Thus, in this study were developed chocolate formulas with improved functionality versus the control prepared without any addition of rosehip and carob powder. Eight chocolate formulations were prepared in laboratory conditions. The antioxidant activity was evaluated on the base of spectrophotometric ferric reducing antioxidant power (FRAP) assay. The total phenolics (TP) content was spectrophotometrically evaluated using the Folin-Ciocalteu colorimetric method. The vitamin C (VC) content has been measured by titration with 2,6-dichlorophenolindophenol sodium salt solution. Our results are useful for food technologists to develop new value-added chocolate formulas by incorporation in the recipe of different functional ingredients. [ABSTRACT FROM AUTHOR]

The purpose of this work, the evaluation of inhibition of corrosion behavior for mild steel in the 3.5%NaCl solution by using recycling materials as inhibitor. Silicate sodium (glass water) were used for protection the mild steel from corrosion. The electrochemical measurements and surface analysis were studied. Polarization measurements prove that decreased the corrosion rate for all concentration additives of inhibitors. These alloys responsible for the inhibitory action due to physiochemical effect and formation protective films. The analyzing done by SEM shows improvement in the passive layer to the corrosive ions on the surface of mild steel surface in 3.5%NaCl solution a present inhibitor. [ABSTRACT FROM AUTHOR]

Energy is the fundamental need of every living organism to carry out various processes internally (metabolic process) and externally. For years together sources like coal, diesel, petrol have been used to generate electrical energy. In the perspective of power generation need, focus on renewable energy sources has to be enhanced so as to suffice the future generation energy demand. During recent years, Microbial fuel cell technology seems to be the most emerging technology in the renewable field. It includes biological production of electricity in the presence of bacteria, substrates and some chemical solution. This paper fully focuses on different designs of fuel chamber and use of different combinations of materials such as bacteria, substrate material, and microbes to enhance the generation of electricity by using this technology. [ABSTRACT FROM AUTHOR]

Under the experiment, we have given an impact assessment of a natural salt solution with herbicide activity on the chemical properties of a quazizemon the highway slope. We have used crude raw brines from the Troitsky deposit of the Krasnoyarsk Territory to study the action mechanism of natural salt with a concentration of 30% on the plant-soil system and the change in its chemical status. According to studies, the natural salt application as an herbicide caused soil alkalinization by 0.11-0.13 pH units while maintaining a neutral response of the soil solution and a composition change in the salts of the aqueous migrate. The maximum amount of toxic salts with a prevalence of NaCl and MgCl2 in the aqueous migrate is found in the variant of 30% natural salt solution + adjuvant Satellite, L.A single treatment of plants by a 30% salt solution with and without an adjuvant defined the occurrence of a weak salinity level of 0-20 cm of the quazizemlayer.A retreatment resulted in the average salinity level in the variant of 30% natural salt solution + adjuvant Satellite, L.The alcalination of the quazizemis impossible. [ABSTRACT FROM AUTHOR]

Test pieces for tensile testing with diameters of 6 and 10 mm were made by lathe machining using a 12 mm in diameter S235JR steel rod as the initial material. They were subjected to accelerated corrosion for 52 days by means of an alternate immersion test in salt solution (AIT). The test pieces were then cleaned and tensile tested. The obtained stress- strain curves were compared and analyzed. The study examines the importance of the initial diameter for the deterioration in the strength and deformability of materials due to corrosion. A method for determining the reduced diameter caused by corrosion without geometric or weight measurements is proposed. This method is suitable for different diameters without further experiments. [ABSTRACT FROM AUTHOR]

Steel resistance is widely required to support most industrial processes. However, to date, numerous marketed steel plates are susceptible to corrosion, especially in the air or in the water environment. This study utilizes the weight loss method to obtain the corrosion rate value on steel, coated with paint, further analyzed for the corrosion rate values respectively by applying 5% NaCl solution and 5% HCl solution. In this study, to obtain differences in the effect of time on the corrosion rate, variations in immersion time are added for 6, 12, 18, 24, and 30 days. HCl solution presents a higher corrosion rate than in NaCl solution on coated steel. HCl solution presents the highest average corrosion rate on the 6th day of 1078.405 mm/y and the lowest corrosion rate on the 30th day of 323.95 mm/y. Meanwhile, NaCl demonstrates the highest average corrosion rate on the 30th day of 13. 701 mm/y and the lowest corrosion rate on the 6th day of 5.016 mm/y. In the immersion of steel with NaCl solution, the increase in immersion time greatly affects the corrosion rate of the steel. In addition, the corrosion rate increases along with the increasing immersion time, meanwhile the results in HCl solution are the opposite. [ABSTRACT FROM AUTHOR]

The article presents the studies obtaining and research new polycondensation type phosphoriccation-exchange resin. The conditions for the phosphorylation of this polymer were selected from the experiments accumulated in relation to the phosphorylation reactions of low- and high-molecular compounds. The resulting polymer had an exchange capacity for a 0.1N NaOH solution – 5,5-5,6 mEq/g and contained 16,5% phosphorus. Based on the studies carried out, the optimal conditions for the synthesis of the styrene-furfural polymer are assumed to be: the reaction temperature is 90°C, the concentration of the ZnCl2 catalyst is 0.07 mol per mole of furfural, and the molar ratio of styrene to furfural is 1:1. There was studied an interaction of the cation exchanger in Na- and H- forms with solutions of salts of copper sulfate, nickel, cobalt, sodium chloride, calcium and uranyl nitrate. In order to elucidate the mechanism of sorption of the cations of these metals, were taken the IR spectra of the cation exchanger in the H and Na form, saturated with copper ions. The less dissociated phosphoric acid groups, the stronger hydrogen bond forms phosphoryl oxygen with OH groups. Therefore, it can be expected that as the cation exchanger is saturated with sodium, the maximum of the band corresponding to the phosphorus-oxygen bond vibrations will slightly shift to longer wavelengths as a result of the destruction of the weaker hydrogen bond. [ABSTRACT FROM AUTHOR]

One of the most promising, rational directions for increasing the strength and other indicators of the quality of building materials is the compaction of cements at the micro level. This is achieved by introducing finely ground fillers and polymer additives. They have a positive effect on the physical and mechanical properties and are economically feasible. The article discusses laboratory tests of the optimal compositions of oil well cements for cementing casing strings. [ABSTRACT FROM AUTHOR]

The synthesis of zircon (ZrSiO4) powders was optimized through the variation of puya sand mass and HCl molarity reduction. This study aimed to produce zircon powder in large quantities more efficiently. The puya sand was obtained from Kereng Pangi, Central Kalimantan, Indonesia. The zircon powders were synthesized through the process of mesh 40 sieves, magnetic separation, ball milling, and HCl immersion. This study used 2 types of sand, namely P1_0 (Puya sand 1) and P2_0 (Puya sand 2), which differ in impurity level, with a mass variation of 30, 40, 50, and 60 g, while the HCl molarity was 0.5 M. Zircon of 30 g is the initial mass referring to the value was used in our previous studies. X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) data were employed for phase assessment and elemental analysis of the synthesized powders, respectively. Results showed that P1_0 powders with all mass variations exhibited pure zircon or zircon productivity increased by 100 % than the initial mass, while P2_0 powder with a mass of zircon sand 40 g has the highest zircon content of 89.84% or productivity increased by 65% than the initial mass. [ABSTRACT FROM AUTHOR]

Residues of pesticides and HM, used in bees care or in crop fields, have negative effects on the health of bees and humans and of the antimicrobial properties of the honey. Investigation of HM and pesticides is vital, since the use of chemical solutions has "rise up" significantly. Our aim was to investigate whether the level of contaminants in honey (Fe, Zn, Pb, Cu, Cd, As, using GC/ECD and GF-AAS) and pesticides: α-HCH, β-HCH, δ-HCH, aldrin, dieldrin, endrin, DDE, DDD, and DDT, alpha -Endosulfan, carbofuran, pirimicarb (by gas chromatography with electron capture determination). Iron (max. 0.76725 mg / kg), Zinc, Lead Copper Cadmium, Arsenic have lower values than the maximum allowed; 0.01 mg/kg is the maximum allowed for pesticides; exception is max. 0.05 mg / kg for DDD, DDT, DDE, Carbofuran and Pirimicarb. The average of the resulting values exceeds the maximum allowed in many cases to four decimal places, as follows: Alpha HCH (max. 0.0158mg / kg), Beta HCH and HCH (by 10-15%), Aldrin (double), alpha endo-sulfan (three times than maximum). Endrin was not detected in any honey samples. Organochlorines in the pp DDE range were below the maximum (0.05 mg / kg). The pyrimicarbon showed lower values. The values determined are not dangerous for the human. [ABSTRACT FROM AUTHOR]

The anthropogenic influence on petroleum reservoirs during oil extraction leads to the emergence of new electron acceptors and donors and exogenous microorganisms. Microbial biodegradation of hydrocarbons in petroleum reservoirs leads to a change of its composition, resulting in a decrease in its cost. The identification of microorganisms capable of in-situ degradation of hydrocarbons under reservoir conditions is critical to understand the role of microbes in hydrocarbon conversion. To analyze microbial biodegradation, it is necessary to have information about the composition and structure of microbial communities in petroleum reservoirs. The most complete analysis of the microbial community, the metagenome analysis, can be carried out using the highthroughput sequencing methods. Before sequencing, isolation of DNA should be carried out, and this is a separate task for research due to its difficulty. There are two approaches for DNA extraction - the first is the analysis of the metagenome of the original oils, which allows to deeply explore their biodiversity. The second approach is to conduct pre-cultivation and enrichment of oil microorganisms. The purpose of this study was to compare total DNA extraction methods from oil samples for subsequent analysis of the metagenomes of flooded producing wells. Eighteen crude oil samples were taken from different wells of the Romashkinskoye oil field (Russia) under anaerobic conditions. The direct extraction was successful only for two of them, once using isooctane and once using Winogradsky's salt solution as eluents. For the other samples, anaerobic enrichment was implemented, is allowed to obtain DNA from 6 more samples. For the last 10 samples, aerobic enrichment was demonstrated to be successful. However, this method of enrichment purely corresponds to the original conditions of the oil well. Further optimization of the direct DNA extraction from crude oil are required. [ABSTRACT FROM AUTHOR]

Experimental studies of the effect of the surface structure of AISI 321 steel on the average convection velocity Uav in the horizontal section of the drop by the MicroPIV method have been carried out. The initial concentration of LiBr salt in an aqueous solution is C0 = 60%. Wall temperature Tw = 90 °C. It was found that the strongest enhancement of Uav was observed for a surface with caverns with a diameter of d2 = 2.5 mm and at the initial time instant τ after the droplet was placed on a heated surface. The difference Uav between the structured and rough wall decreases with increasing τ. This decrease in Uav is associated with: 1) heating of the solution from the wall and a decrease in ΔT; 2) a decrease in the height of the droplets and an increase in the viscosity of the salt solution due to evaporation. [ABSTRACT FROM AUTHOR]

We consider the transient wave propagation problem of linear, isotropic and elastic plate applied SH impact loading on the surface. Analytical solution of half-space obtained by the inverse Fourier-Laplace double transform using Cagniard-De Hoop method. The wave propagation problem of plate was considered by using a half-space exact solution and reflect wave from the boundary of plate are expressed using the image method. Some numerical results of stress and displacement components are presented. The mathematical technique appear in the basic problem can apply to the transient P wave propagation and more advanced problems. [ABSTRACT FROM AUTHOR]

Experimental studies for the evaporation of a sessile and hanging droplet of aqueous salt solution were carried out. When spray cooling a hot wall, it is required to simulate both the heat transfer of falling droplets and the heat transfer of sessile droplets on the wall. It is shown that the ratio of the maximum velocity to the average convection velocity is approximately 2.5-3 both for a hanging and a sessile droplet of salt solution. [ABSTRACT FROM AUTHOR]