63 research outputs found
Utilization of Poly(Polyvinyl Alcohol-g-2-Ethylhexyl Acrylate) as Admixture for Mortar
We investigated the physico-mechanical properties of mortar mixed with copolymers based on polyvinyl alcohol (PVA) and 2-ethylhexyl acrylate (2-EHA) and synthesized by grafting using ammonium persulfate (APS) as an initiator. Increasing the amount of 2-EHA in the copolymer from 4% to 8% reduced the water/cement (W/C) ratio, the initial and final setting times, and the water absorption of mortar, while it increased its compressive strength.<br/
Effects of surfactants on the properties of mortar containing styrene/methacrylate superplasticizer
The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA. Copyright © 2014 El-Sayed Negim et al.The authors gratefully acknowledge the funding provided by the European Union under the Marie Curie Action International Incoming Fellowships (FP7-PEOPLE-2011-IIF), Grant agreement PIIF-GA-2011 (Project no. 300427) ProSeC, for research on the production of sustainable self-compacting concrete.Published versio
Effect of Copolymer Latexes on Physicomechanical Properties of Mortar Containing High Volume Fly Ash as a Replacement Material of Cement
© 2014 El-Sayed Negim et al. This paper investigates the physicomechanical properties of mortar containing high volume of fly ash (FA) as partial replacement of cement in presence of copolymer latexes. Portland cement (PC) was partially replaced with 0, 10, 20, 30 50, and 60% FA. Copolymer latexes were used based on 2-hydroxyethyl acrylate (2-HEA) and 2-hydroxymethylacrylate (2-HEMA). Testing included workability, setting time, absorption, chemically combined water content, compressive strength, and scanning electron microscopy (SEM). The addition of FA to mortar as replacement of PC affected the physicomechanical properties of mortar. As the content of FA in the concrete increased, the setting times (initial and final) were elongated. The results obtained at 28 days of curing indicate that the maximum properties of mortar occur at around 30% FA. Beyond 30% FA the properties of mortar reduce and at 60% FA the properties of mortar are lower than those of the reference mortar without FA. However, the addition of polymer latexes into mortar containing FA improved most of the physicomechanical properties of mortar at all curing times. Compressive strength, combined water, and workability of mortar containing FA premixed with latexes are higher than those of mortar containing FA without latexes.The authors gratefully acknowledge the funding provided by the European Union under the Marie Curie Action: International Incoming Fellowships (FP7-PEOPLE-2011-IIF), Grant agreement PIIF-GA-2011 (Project no. 300427) ProSeC for research on the production of sustainable self-compacting concrete.Published versio
Using Various Models for Predicting Soil Organic Carbon Based on DRIFT-FTIR and Chemical Analysis
Soil organic carbon (SOC) is a crucial factor influencing soil quality and fertility. In this particular investigation, we aimed to explore the possibility of using diffuse reflectance infrared fourier transform spectroscopy (DRIFT-FTIR) in conjunction with machine-learning models, such as partial least squares regression (PLSR), artificial neural networks (ANN), support vector regression (SVR) and random forest (RF), to estimate SOC in Sohag, Egypt. To achieve this, we collected a total of ninety surface soil samples from various locations in Sohag and estimated the total organic carbon content using both the Walkley-Black method and DRIFT-FTIR spectroscopy. Subsequently, we used the spectral data to develop regression models using PLSR, ANN, SVR, and RF. To evaluate the performance of these models, we used several evaluation parameters, including root mean square error (RMSE), coefficient of determination (R2), and ratio of performance deviation (RPD). Our survey results revealed that the PLSR model had the most favorable performance, yielding an R2 value of 0.82 and an RMSE of 0.006%. In contrast, the ANN, SVR, and RF models demonstrated moderate to poor performance, with R2 values of 0.53, 0.27, and 0.18, respectively. Overall, our study highlights the potential of combining DRIFT-FTIR spectroscopy with multivariate analysis techniques to predict SOC in Sohag, Egypt. However, additional studies and research are needed to improve the accuracy or predictability of machine-learning models incorporated into DRIFT-FTIR analysis and to compare DRIFT-FTIR analysis techniques with conventional soil chemical measurements
The determination of physico-chemical pasta quality indicators with the addition of millet 3,8 %
This article discusses the quality indicators of pasta products obtained by partially replacing wheat grits of the highest grade with millet ground 3.8% (of the total mass of the dough, taking into account water). The addition of millet is due to the fact that the raw materials are saturated with various vitamins. As part of the study, organoleptic and physico-chemical parameters (28% humidity) after the procedure of «pressing raw materials» were considered and the indicator of shape preservation after the «cooking» process was determined. The results obtained in terms of quality indicators meet the requirements established in the standardization documents, at the same time, the nutritional properties of the product are improved, the energy value is 337.8 kcal (proteins 10.5 g, fats 1.1 g, carbohydrates 71.4 g per 100 g of pasta), the replacement of wheat flour of the highest grade with more economic raw materials is carried out. Quality indicators are determined in accordance with TR CU 021/2011 «On food safety», TR CU 022/2011 «Food products in terms of their labeling», TR CU 029/2012 «Safety requirements for food additives, flavorings and technological aids», regulatory and technical documents GOST 31743-2017 «Pasta. General technical conditions», GOST 31964-2012 «Pasta. Acceptance rules and methods for determining quality», GOST 572-2016 «Millet millet. Technical conditions». The enrichment of pasta with millet improves the biological, nutritional properties of the product. At the same time, the use of millet as a raw material reduces the cooking time of pasta, the form after cooking will meet the established requirements
Quality characteristics of the shape preservation of cooked pasta with millet addition at different time intervals
The current study presents the indicators of shape preservation of cooked pasta by adding 7.7% millet in various time intervals. The experiments were conducted immediately after the pasta cooking process and after two hours. In the Eurasian Economic Union and the Republic of Kazakhstan, the quality indicators were produced by considering the established methodologies stated in the standardized papers. The interstate standard GOST 31964-2012, "Pasta products. Acceptance rules and methods of quality determination," was used to determine the shape preservation of cooked pasta. The study aimed to determine and compare cooked pasta's shape preservation indicators (consumer properties), considering a certain time interval. Pasta needs five minutes to cook. These days, though, pasta manufacturers specify the required cooking time – eight, nine, ten, or eleven minutes – on their packages. The study's findings indicate that the safety of pasta containing "7.7% millet after 2 (hours) from the moment of cooking" and "with the addition of 7.7% millet after cooking" is negligible by 1-2 N; however, data from 4-24 N show a more notable difference in a comparable scenario. The experiments were conducted at the Federal State Autonomous Scientific Institution "Scientific Research Institute of the Bakery Industry", Moscow, Russian Federation. The corresponding data was obtained according to the results of the conducted studies
Investigation of the Properties of Metallurgical Slags and Dust of Electro Filters to Obtain Protective Anticorrosive Coatings
Corrosion-related
irreparable metal failures can cause massive losses in various sectors,
including agricultural engineering and construction. Steel structures are
typically coated to withstand corrosion pressures during the service life
specified in technical standards to avoid corrosion damage. This article
presents research results on metallurgical cast iron slags and a mixture of
slags with electro-filter dust to form silicate anticorrosive coatings. X-ray
phase analysis, electron, and optical microscopy were used to analyze the
surface nucleation of crystals in glasses using cast iron slags, a combination
of steelmaking slag, and electro-filter dust with the addition of Cr2O3. It is shown that the
main phases crystallizing from the surface of the samples are diopside . When 1.5 - 2.0 wt.% Cr2O3 was added, the results showed that diopside phase
glasses could be made with a cast iron slag level of up to 72 wt.%. Studies
have shown the important role of Fe2+, and
Mg2+, especially in samples
containing cast iron slag, based on the most fusible compounds obtained. The
optimal model of glass formation and crystallization was established as a
result of the analysis of these compositions, and the microhardness of slag
glass-crystalline materials was investigated. It was found that the hardness of
the obtained glass-crystal materials increases in the presence of chromium
oxide. The research revealed the possibility of synthesizing glass-crystal
materials from cast-iron slags and dust of electro-filters
Preparation and Characterization of Acrylic Primer for Concrete Substrate Application
This study dealt with the properties of acrylic primer for concrete substrate using acrylic syrup, made from a methyl methacrylate monomer solution of terpolymers. Terpolymer systems consisting of methyl methacrylate (MMA), 2-ethylhexyl acrylate (2-EHA), and methacrylic acid (MAA) with different chemical composition ratios of MMA and 2-EHA were synthesized through bulk polymerization using azobisisobutyronitrile (AIBN) as initiator. The terpolymer composition is characterized by FTIR, 1H NMR, DSC, TGA, and SEM. The glass transition temperature and the thermal stability increased with increasing amounts of MMA in the terpolymer backbone. The effect of chemical composition of terpolymers on physicomechanical properties of primer films was investigated. However, increasing the amount of MMA in terpolymer backbone increased tensile and contact angle of primer films while elongation at break, water absorption, and bond strength are decreased. In particular, the primer syrup containing 65% 2-EHA has good bonding strength with concrete substrate around 1.1 MPa
Enhancement of apixaban's solubility and dissolution rate by inclusion complex (β-cyclodextrin and hydroxypropyl β-cyclo¬dextrin) and computational calculation of their inclusion complexes
Background and Purpose: Apixaban (AP) is a factor X inhibitor, an orally active drug that inhibits blood coagulation for better prevention of venous thromboembolism. It has poor solubility, dissolution rate and low bioavailability. The aim of this study was to improve the aqueous solubility and dissolution rate of oral AP as a step to enhance its bioavailability by preparing it as an inclusion complex with beta- and hydroxy propyl beta-cyclodextrin. Experimental Approach: A simple, rapid method of analysis of AP was developed using ultraviolet spectrophotometry (UV) and partially validated in terms of linearity, precision and accuracy, recovery, and robustness. AP was prepared as a complex with beta cyclodextrin (βCD) and hydroxy propyl beta cyclodextrin (HPβCD) in weight ratios 1:1, 1:2, and 1:3 by kneading, solvent evaporation and spray drying methods and characterized by Fourier transfer infra-red (FTIR), differential scanning calorimetry (DSC), and percent drug content in each of the prepared complex. Using the computer simulation, the interactions of AP with βCD and HPβCD were investigated. Key Results: The phase solubility study showed that the solubility of AP was greatly enhanced from 54×10-3 mmol /L to 66 mmol/L using HPβCD with acceptable stability constant. Computer docking supports the formation of a stable 1:1 complex between AP and CD’s. The dissolution test results showed that the complex gave a significantly higher percentage of drug release (95%) over one hour compared to the free AP (60%) (p<0.05). Conclusion: AP- HPβCD complex in the ratio of 1:2 (w/w) can significantly improve the solubility and in vitro dissolution rate of AP
Quantitative analysis of total phenolic and flavonoid compounds in different extracts from ginger plant (Zingiber officinale) and evaluation of their anticancer effect against colorectal cancer cell lines
Objectives: To quantify quercetin, gallic acid, rutin, naringin, and caffeic acid in the rhizome of Zingiber officinale different extracts in seven different solvents (methanol, ethanol, ethyl acetate, water, dichloromethane, chloroform, and n-hexane), for the first time, using HPLC/UV. Also, to study the anticancer activity of Zingiber officinale different extracts by evaluating its in vitro toxicity on HT-29 colorectal cancer cell line. Methods: The fresh and dried rhizomes were extracted using Soxhlet (SOX) and maceration (MAC) methods. Separation of compounds was conducted using HPLC. The cell line used for MTT cell proliferation assay antiproliferative; is HT-29 (HTB-38) colorectal adenocarcinoma. Results: The MTT test indicated that powder ginger extracted by MAC or SOX showed high cytotoxicity activity (IC50&lt;50) against HT-29 cells, except water using SOX, which showed mild cytotoxicity activity. The fresh ginger extracted by MAC using dichloromethane and those extracted by SOX using ethyl acetate showed strong cytotoxicity activity (IC50 &lt;50). Conclusion: The phenolic and flavonoid contents of ginger can vary depending on the different extracts from ginger plant. Also, HPLC results revealed that quercetin was the highest in all extracts
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