Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.387_periodico36_pgs_372_389.pdf
A. Tatarkanov, I. Alexandrov, A. Olejnik
Tubular parts with an external finned heat-exchanging surface are usually produced by the laborious method of cutting on lathes. Besides, there is a method for the high-performance manufacturing of fins by cold knurling with ring-cut knurls, which, compared with cutting, reduces labor intensity by two to six times with a significant increase in the operational properties of the product. The disadvantage of the cold knurling method with ring-cut knurls can be unwanted surface defects and deformations of the entire product. Obtaining finned surfaces on ring blanks with high surface quality during knurling requires accurate calculation of the ratio of longitudinal and transverse strains. The most important factors determining the ratio of longitudinal and transverse strains (rolling-out and rolling-off) are the length and width of the contact surface. The need for a quantitative assessment of the parameters of longitudinal and transverse strains determined the purpose of this manuscript. This study aimed to develop a methodology for calculating the contact surface of a knurl with a ring blank (pipe) when knurling with ring-cut knurls. The proposed method for calculating the knurl's contact surface with a tube when knurling with ring-cut knurls allows for estimating the recommended range of pipe sizes for knurling. Based on the dependencies mentioned in the manuscript, the limiting sizes for blank pipes were calculated to ensure high-quality finning. Experiments on cold rolling of ribbing on pipes with different lengths and diameter ratios were carried out, confirming the possibility of using the proposed methodology for calculating the knurl's contact surface with a pipe when knurling heat-exchanging finning with ring-cut knurls.
{"title":"EVALUATION OF THE CONTACT SURFACE PARAMETERS AT KNURLING FINNED HEAT-EXCHANGING SURFACE BY KNURLS AT RING BLANKS","authors":"A. Tatarkanov, I. Alexandrov, A. Olejnik","doi":"10.52571/ptq.v17.n36.2020.387_periodico36_pgs_372_389.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.387_periodico36_pgs_372_389.pdf","url":null,"abstract":"\u0000Tubular parts with an external finned heat-exchanging surface are usually produced by the laborious method of cutting on lathes. Besides, there is a method for the high-performance manufacturing of fins by cold knurling with ring-cut knurls, which, compared with cutting, reduces labor intensity by two to six times with a significant increase in the operational properties of the product. The disadvantage of the cold knurling method with ring-cut knurls can be unwanted surface defects and deformations of the entire product. Obtaining finned surfaces on ring blanks with high surface quality during knurling requires accurate calculation of the ratio of longitudinal and transverse strains. The most important factors determining the ratio of longitudinal and transverse strains (rolling-out and rolling-off) are the length and width of the contact surface. The need for a quantitative assessment of the parameters of longitudinal and transverse strains determined the purpose of this manuscript. This study aimed to develop a methodology for calculating the contact surface of a knurl with a ring blank (pipe) when knurling with ring-cut knurls. The proposed method for calculating the knurl's contact surface with a tube when knurling with ring-cut knurls allows for estimating the recommended range of pipe sizes for knurling. Based on the dependencies mentioned in the manuscript, the limiting sizes for blank pipes were calculated to ensure high-quality finning. Experiments on cold rolling of ribbing on pipes with different lengths and diameter ratios were carried out, confirming the possibility of using the proposed methodology for calculating the knurl's contact surface with a pipe when knurling heat-exchanging finning with ring-cut knurls.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42348471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.677_periodico36_pgs_662_673.pdf
Ramacos Fardela, G. Suparta, Ahmad Ashari, K. Triyana
Radiation is the energy emitted from electrons in particles or photons (waves) and is classified into nonionized and ionized. Ionizing radiation demonstrates the ability to disintegrate matter along its path and has proven beneficial in medicine. Exposure to this energy tends to instigate adverse effects on human health and heredity (genetics). However, the radiation is not directly measured but requires a nuclear detector to serve as a monitoring device. Radiation workers’ awareness of ionizing radiation levels in the work environment is one of the most important factors in preventing the negative effects of radioactivity. This is possibly identified using various types of detectors. This experiment aimed to provide an overview of radiation dose rate measurement under two conditions. First is the event of contamination in the work environment. The second involves using a detector to solely determine the dose rate from a single source, e.g., gamma radiation. Therefore, the radiation dose rate was evaluated by maximizing the use of detectors with a GUI as a survey meter for contamination. The highest rate (261.42 μSv / h) was observed at a distance of 5 mm, while the least (69.21 μSv / h) was recorded at 50 mm. Also, a dose rate of 5.4 μSv / h and 1.32 μSv / h was obtained at a 5 mm and 50 mm distance from the radiation source, respectively, following the operation as a gamma survey meter. This result shows strong linearity between both measurements and is estimated to accurately determine the contamination level of radioactive elements, alongside the doses rate of the gamma radiation emitting elements.
{"title":"RADIATION DOSE RATE MEASUREMENT FOR PROTECTION PROGRAMS IN THE WORK ENVIRONMENT FOR THE HEALTH WORKERS: AN EXPERIMENTAL STUDY","authors":"Ramacos Fardela, G. Suparta, Ahmad Ashari, K. Triyana","doi":"10.52571/ptq.v17.n36.2020.677_periodico36_pgs_662_673.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.677_periodico36_pgs_662_673.pdf","url":null,"abstract":"\u0000Radiation is the energy emitted from electrons in particles or photons (waves) and is classified into nonionized and ionized. Ionizing radiation demonstrates the ability to disintegrate matter along its path and has proven beneficial in medicine. Exposure to this energy tends to instigate adverse effects on human health and heredity (genetics). However, the radiation is not directly measured but requires a nuclear detector to serve as a monitoring device. Radiation workers’ awareness of ionizing radiation levels in the work environment is one of the most important factors in preventing the negative effects of radioactivity. This is possibly identified using various types of detectors. This experiment aimed to provide an overview of radiation dose rate measurement under two conditions. First is the event of contamination in the work environment. The second involves using a detector to solely determine the dose rate from a single source, e.g., gamma radiation. Therefore, the radiation dose rate\u0000was evaluated by maximizing the use of detectors with a GUI as a survey meter for contamination. The highest rate (261.42 μSv / h) was observed at a distance of 5 mm, while the least (69.21 μSv / h) was recorded at 50 mm. Also, a dose rate of 5.4 μSv / h and 1.32 μSv / h was obtained at a 5 mm and 50 mm distance from the radiation source, respectively, following the operation as a gamma survey meter. This result shows strong linearity between both measurements and is estimated to accurately determine the contamination level of radioactive elements, alongside the doses rate of the gamma radiation emitting elements.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45335225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.689_periodico36_pgs_674_687.pdf
A. Hindayani, Muhammad Rizky Mulyana, H. Budiman, N. T. E. Darmayanti, Oman Zuas
Measurement of carbon dioxide (CO2), oxygen (O2), and nitrogen (N2) concentration in modified atmosphere packaging (MAP) food is critical to be carried out by the food industry. A slight variation in concentrations of CO2, O2, and N2 in food packaging may have a significant impact on product quality and safety for human health. Accurate and reliable measurement of CO2, O2, and N2 concentrations in food packaging is crucial, and it can only be achieved by calibrating the gas analyzer. This study aimed to develop gas mixtures for the calibration of CO2, O2, and N2 gas analyzers at a typical concentration range of modified atmosphere packaging. The calibration gas mixtures were prepared gravimetrically by following ISO 6142. The concentration ranges of CO2, O2, and N2 for calibration gas mixtures were set at 9-19% mol/mol, 1-5% mol/mol, and 74-88% mol/mol, respectively. Each parent gas was identified for its impurities using gas chromatography with a pulsed discharge helium ionization detector (GC-PDHID). The compositions of CO2, O2, and N2 in the mixtures were verified by evaluating the internal consistency within the prepared gas mixtures using gas chromatography with a thermal conductivity detector (GC-TCD). The short term stability of the prepared gas mixtures was evaluated using an equal division method. The result showed that good internal consistency was achieved between the gravimetrical and GC’s verification values, having linear regression coefficient (R2) ≥ 0.999. The t-test result has shown that CO2 has better short term stability than O2 and N2. In conclusion, the developed calibration gas mixtures at a typical concentration range of modified atmosphere packaging have shown satisfying results for CO2 component. However, further evaluation is still required to minimize the instability of O2 and N2 components.
{"title":"DEVELOPMENT OF CALIBRATION GAS MIXTURES (CARBON DIOXIDE AND OXYGEN IN NITROGEN MATRIX) AT A TYPICAL CONCENTRATION RANGE OF MODIFIED ATMOSPHERE PACKAGING","authors":"A. Hindayani, Muhammad Rizky Mulyana, H. Budiman, N. T. E. Darmayanti, Oman Zuas","doi":"10.52571/ptq.v17.n36.2020.689_periodico36_pgs_674_687.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.689_periodico36_pgs_674_687.pdf","url":null,"abstract":"\u0000Measurement of carbon dioxide (CO2), oxygen (O2), and nitrogen (N2) concentration in modified atmosphere packaging (MAP) food is critical to be carried out by the food industry. A slight variation in concentrations of CO2, O2, and N2 in food packaging may have a significant impact on product quality and safety for human health. Accurate and reliable measurement of CO2, O2, and N2 concentrations in food packaging is crucial, and it can only be achieved by calibrating the gas analyzer. This study aimed to develop gas mixtures for the calibration of CO2, O2, and N2 gas analyzers at a typical concentration range of modified atmosphere packaging. The calibration gas mixtures were prepared gravimetrically by following ISO 6142. The concentration ranges of CO2, O2, and N2 for calibration gas mixtures were set at 9-19% mol/mol, 1-5% mol/mol, and 74-88%\u0000mol/mol, respectively. Each parent gas was identified for its impurities using gas chromatography with a pulsed discharge helium ionization detector (GC-PDHID). The compositions of CO2, O2, and N2 in the mixtures were verified by evaluating the internal consistency within the prepared gas mixtures using gas chromatography with a thermal conductivity detector (GC-TCD). The short term stability of the prepared gas mixtures was evaluated using an equal division method. The result showed that good internal consistency was achieved between the gravimetrical and GC’s verification values, having linear regression coefficient (R2) ≥ 0.999. The t-test result has shown that CO2 has better short term stability than O2 and N2. In conclusion, the developed calibration gas mixtures at a typical concentration range of modified atmosphere packaging have shown satisfying results for CO2 component. However, further evaluation is still required to minimize the instability of O2 and N2 components.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48176085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n35.2020.08_mironova_pgs_83_92.pdf
I. Mironova, Z. Galieva, I. Gazeev, Alexander Belousov, Venire Galimova
The role of fats in nutrition is determined by their high-calorie content and participation in the construction of body tissues, together with proteins and carbohydrates. Enriched nutrition is of great importance in the complex of issues that determine its usefulness. Thus, the question of the effect of probiotics and sorbents in the diet on the animal organism has become very relevant. The purpose of the work was a comparative assessment of the composition and properties of adipose tissue of rams, consuming together and separately preparations with sorption and probiotic effect. The studies were carried out in two stages. In the first, during the scientific and economic experiment, 80 newborn rams grew and developed up to a year of age, followed by the slaughter of three animals from each group. In the second stage, samples of internal fat were examined according to some indicators. Sensory analysis revealed that all internal fat samples met the established requirements, while the color and consistency of the experimental samples improved. The dry matter content, including fat in the experimental samples of fat tissue, increased, and moisture decreased. The physical and technical parameters of internal fat also changed in the intergroup aspect. In the control sample, the iodine number decreased, and the saponification number, pour point, and melting point increased. Calculation of energy value indicates that in the first sample, the indicator increased by 0.08 MJ (0.23%); Group II – by 0.16 MJ (0.45%) and group III – by 0.25 MJ (0.70%). According to the sum of monounsaturated fatty acids, young group III was in the lead. The content of polyunsaturated fatty acids was the opposite. The biological effectiveness of fats is determined by the ratio that was better in the experimental samples. Thus, the inclusion of fodder additives in the diet of the rams of the Romanov breed helps to improve the quality of raw materials.
{"title":"CHANGE OF THE CHEMICAL, FAT AND ACID COMPOSITION AND PHYSICAL AND TECHNICAL PROPERTIES OF LAMB FAT UNDER INFLUENCE OF VARIOUS FODDER BACKGROUND","authors":"I. Mironova, Z. Galieva, I. Gazeev, Alexander Belousov, Venire Galimova","doi":"10.52571/ptq.v17.n35.2020.08_mironova_pgs_83_92.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n35.2020.08_mironova_pgs_83_92.pdf","url":null,"abstract":"The role of fats in nutrition is determined by their high-calorie content and participation in the construction of body tissues, together with proteins and carbohydrates. Enriched nutrition is of great importance in the complex of issues that determine its usefulness. Thus, the question of the effect of probiotics and sorbents in the diet on the animal organism has become very relevant. The purpose of the work was a comparative assessment of the composition and properties of adipose tissue of rams, consuming together and separately preparations with sorption and probiotic effect. The studies were carried out in two stages. In the first, during the scientific and economic experiment, 80 newborn rams grew and developed up to a year of age, followed by the slaughter of three animals from each group. In the second stage, samples of internal fat were examined according to some indicators. Sensory analysis revealed that all internal fat samples met the established requirements, while the color and consistency of the experimental samples improved. The dry matter content, including fat in the experimental samples of fat tissue, increased, and moisture decreased. The physical and technical parameters of internal fat also changed in the intergroup aspect. In the control sample, the iodine number decreased, and the saponification number, pour point, and melting point increased. Calculation of energy value indicates that in the first sample, the indicator increased by 0.08 MJ (0.23%); Group II – by 0.16 MJ (0.45%) and group III – by 0.25 MJ (0.70%). According to the sum of monounsaturated fatty acids, young group III was in the lead. The content of polyunsaturated fatty acids was the opposite. The biological effectiveness of fats is determined by the ratio that was better in the experimental samples. Thus, the inclusion of fodder additives in the diet of the rams of the Romanov breed helps to improve the quality of raw materials.","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48864691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n35.2020.04_avdarsol_pgs_41_54.pdf
S. Avdarsol, L. Rakhimzhanova, B. Bostanov, Ainur Ye. Sagimbaeva, Tiyshtik Khakimova
For a long time, the primary approach to assessment was the normative approach when the individual achievements of students were compared with a particular norm (the results of most students). Recently, domestic pedagogical research has been developing a criteria-based approach to assessing academic achievement when students' achievements are compared with the amount of knowledge that needs to be acquired at a particular stage of training. This study aimed to determine the role of criteria-based assessment in the formation of students functional literacy in computer science and to build a criteria-based assessment model in the development of functional literacy beyond to demonstrate the effectiveness of the methods of formation of students functional literacy in computer science. The leading research methods were the criteria-based assessment methodology developed by the authors and the method of formative assessment. Some elements of the methodology of forming evaluation were considered. For further development of the methods for the formation of students functional literacy in computer science, a criteria-based assessment model has been built. The introduction of criteria-based assessment will allow to switch to a formative evaluation aimed at developing student competence. The evaluation, consisting of criteria that a student understands, stimulates him and makes the learning process meaningful. Based on practical experiments and the proposed criteria-based assessment, the effectiveness of methods for the formation of students functional literacy in computer science has been proved.
{"title":"CRITERIA-BASED ASSESSMENT AS THE WAY OF FORMING STUDENTS FUNCTIONAL LITERACY IN COMPUTER SCIENCE","authors":"S. Avdarsol, L. Rakhimzhanova, B. Bostanov, Ainur Ye. Sagimbaeva, Tiyshtik Khakimova","doi":"10.52571/ptq.v17.n35.2020.04_avdarsol_pgs_41_54.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n35.2020.04_avdarsol_pgs_41_54.pdf","url":null,"abstract":"For a long time, the primary approach to assessment was the normative approach when the individual achievements of students were compared with a particular norm (the results of most students). Recently, domestic pedagogical research has been developing a criteria-based approach to assessing academic achievement when students' achievements are compared with the amount of knowledge that needs to be acquired at a particular stage of training. This study aimed to determine the role of criteria-based assessment in the formation of students functional literacy in computer science and to build a criteria-based assessment model in the development of functional literacy beyond to demonstrate the effectiveness of the methods of formation of students functional literacy in computer science. The leading research methods were the criteria-based assessment methodology developed by the authors and the method of formative assessment. Some elements of the methodology of forming evaluation were considered. For further development of the methods for the formation of students functional literacy in computer science, a criteria-based assessment model has been built. The introduction of criteria-based assessment will allow to switch to a formative evaluation aimed at developing student competence. The evaluation, consisting of criteria that a student understands, stimulates him and makes the learning process meaningful. Based on practical experiments and the proposed criteria-based assessment, the effectiveness of methods for the formation of students functional literacy in computer science has been proved.","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44332779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.63_periodico36_pgs_47_57.pdf
H. Akbar, E. Surojo, D. Ariawan, A. Prabowo
Lightweight materials with low-cost production have been developed in recent years. The addition of ceramics and oxide particles such as Al2O3, SiC, and SiO2 has been improving in the mechanical properties of aluminum matrix composites (AMCs). As a solution, the use of natural reinforcing material continues to investigate. This paper investigates sea sand as an alternative reinforcement to AMCs. The Al 6061 was used as the matrix and sea sand as reinforcement. The manufacturing of the composite was conducted by stir casting route with variation 0, 2, 4, 6 %wt of the reinforcement. The composite was tested in hardness and tensile strength, the hardness test was obtained according to ASTM E-10, and the tensile test was conducted according to JIS Z2201 standard. Composite density decreases linearly with the addition of the reinforcement from 2 %wt to 6%wt, and the same phenomenon is obtained in porosity, the porosity increases with the addition of sea sand particles from 2%wt to 6%wt. The decline in density due to the lower density of sea sand particles compared to the aluminum matrix. Higher the sea sand particle that disperses into the matrix resulted in a lower density of the composite. Increasing porosity caused a higher fraction of reinforcement resulting in wider surface contact between matrix and reinforcement that promote the porosity. The hardness and ultimate tensile strength of AMCs increase with increasing of sea sand particles content. The presence of an oxide compound on the sea sand increased the mechanical properties of the composite. Increasing in mechanical properties indicate the sea sand particle dispersed into the matrix and sea sand can be used as engineering purpose material.
{"title":"TECHNICAL INVESTIGATION OF SEA SAND REINFORCEMENT FOR NOVEL AL6061- SEA SAND COMPOSITES: IDENTIFICATION OF PERFORMANCE AND MECHANICAL PROPERTIES","authors":"H. Akbar, E. Surojo, D. Ariawan, A. Prabowo","doi":"10.52571/ptq.v17.n36.2020.63_periodico36_pgs_47_57.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.63_periodico36_pgs_47_57.pdf","url":null,"abstract":"\u0000Lightweight materials with low-cost production have been developed in recent years. The addition of ceramics and oxide particles such as Al2O3, SiC, and SiO2 has been improving in the mechanical properties of aluminum matrix composites (AMCs). As a solution, the use of natural reinforcing material continues to investigate. This paper investigates sea sand as an alternative reinforcement to AMCs. The Al 6061 was used as the matrix and sea sand as reinforcement. The manufacturing of the composite was conducted by stir casting route with variation 0, 2, 4, 6 %wt of the reinforcement. The composite was tested in hardness and tensile strength, the hardness test was obtained according to ASTM E-10, and the tensile test was conducted according to JIS Z2201 standard. Composite density decreases linearly with the addition of the reinforcement from 2 %wt to 6%wt, and the same phenomenon is obtained in porosity, the porosity increases with the addition of sea sand particles from 2%wt to 6%wt. The decline in density due to the lower density of sea sand particles compared to the aluminum matrix. Higher the sea sand particle that disperses into the matrix resulted in a lower density of the composite. Increasing porosity caused a higher fraction of reinforcement resulting in wider surface contact between matrix and reinforcement that promote the porosity. The hardness and ultimate tensile strength of AMCs increase with increasing of sea sand particles content. The presence of an oxide compound on the sea sand increased the mechanical properties of the composite. Increasing in mechanical properties indicate the sea sand particle dispersed into the matrix and sea sand can be used as engineering purpose material.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46044790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.1125_periodico36_pgs_1110_1126.pdf
C. L. Suryani, T. Wahyuningsih, A. Supriyadi, U. Santoso
Chlorophyll is a natural coloring agent that has antioxidant activity. During the extraction and food processing process, chlorophyll is easily degraded and derivatized. The derivatization process results in changes in the chemical structure of chlorophyll which can result in a change in color and its antioxidant activity. The other extracted minor compounds can affect its antioxidant activity. This study aimed to identify the chemical structure changes of chlorophyll extracted from pandan (Pandanus amaryllifolius Roxb) leaves as affected by the derivatization process and evaluate the antioxidant activity of the extracts and fractions of chlorophyll and its derivatives. Chlorophyll was extracted from pandan leaves with acetone, derivatized, and then purified by fractionation using column chromatography. Chlorophyll extract and its derivatives were analyzed for total carotenoid, total phenolic, and flavonoid contents. The antioxidant activity of extract and fraction was measured by the inhibition of peroxidation of linoleic acid, radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/ antioxidant power (FRAP) ability, and metal chelating assay. Based on the FTIR and MS/MS spectra, it was observed that the first derivatives were pheophytin and chlorophyllide, while the second derivative was pheophorbide. The other extracted compounds, including phenolic compounds, flavonoids, and carotenoids, might enhance the antioxidant activity of the chlorophyll derivatives. The inhibition rate of linoleic acid peroxidation by chlorophyll, chlorophyllide, and pheophorbide extract was not significantly different from BHT, where pheophytin extract was lower. The radical scavenging activity of DPPH and FRAP assay showed that chlorophyll and chlorophyllide extracts exhibited higher activity, followed by pheophytin and pheophorbide. Meanwhile, the metal chelating assay showed that chlorophyllide fraction exhibited the lowest activity. Therefore, the antioxidant activity of the first derivatives of chlorophyll was higher than the second derivatives. In general, the extract of chlorophyll and its derivatives exhibited higher antioxidant activity than that of their fraction.
{"title":"DERIVATIZATION OF CHLOROPHYLL FROM PANDAN (Pandanus amaryllifolius Roxb.) LEAVES AND THEIR ANTIOXIDANT ACTIVITY","authors":"C. L. Suryani, T. Wahyuningsih, A. Supriyadi, U. Santoso","doi":"10.52571/ptq.v17.n36.2020.1125_periodico36_pgs_1110_1126.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.1125_periodico36_pgs_1110_1126.pdf","url":null,"abstract":"\u0000Chlorophyll is a natural coloring agent that has antioxidant activity. During the extraction and food processing process, chlorophyll is easily degraded and derivatized. The derivatization process results in changes in the chemical structure of chlorophyll which can result in a change in color and its antioxidant activity. The other extracted minor compounds can affect its antioxidant activity. This study aimed to identify the chemical structure changes of chlorophyll extracted from pandan (Pandanus amaryllifolius Roxb) leaves as affected by the derivatization process and evaluate the antioxidant activity of the extracts and fractions of chlorophyll and its derivatives. Chlorophyll was extracted from pandan leaves with acetone, derivatized, and then purified by fractionation using column chromatography. Chlorophyll extract and its derivatives were analyzed for total carotenoid, total phenolic, and flavonoid contents. The antioxidant activity of extract and fraction was measured by the inhibition of peroxidation of linoleic acid, radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/ antioxidant power (FRAP) ability, and metal chelating assay. Based on the FTIR and MS/MS spectra, it was observed that the first derivatives were pheophytin and chlorophyllide, while the second derivative was pheophorbide. The other extracted compounds, including phenolic compounds, flavonoids, and carotenoids, might enhance the antioxidant activity of the chlorophyll derivatives. The inhibition rate of linoleic acid peroxidation by chlorophyll, chlorophyllide, and pheophorbide extract was not significantly different from BHT, where pheophytin extract was lower. The radical scavenging activity of DPPH and FRAP assay showed that chlorophyll and chlorophyllide extracts exhibited higher activity, followed by pheophytin and pheophorbide. Meanwhile, the metal chelating assay showed that chlorophyllide fraction exhibited the lowest activity. Therefore, the antioxidant activity of the first derivatives of chlorophyll was higher than the second derivatives. In general, the extract of chlorophyll and its derivatives exhibited higher antioxidant activity than that of their fraction.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46665881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.101_periodico36_pgs_85_99.pdf
R. D. Costa, D. C. Silva, S. Gualberto, Paulo Sávio Damásio Da Silva, M. A. M. Costa
The control of Aedes aegypti, which transmits several arboviruses of importance to public health, has as strategies the use of synthetic insecticides, integrated with environmental control. Its control is mainly directed to the larvae and adult phases. The egg phase is difficult to control, as it has great resistance to environmental conditions. The objective of this work was to evaluate the ovicidal potential of the essential oil obtained from the leaves of Croton argyrophyllus, on Aedes aegypti, as well as to determine the moisture content, the yield, and its chemical composition. The eggs were exposed to the aqueous solution of the essential oil in 10% Tween 80, in the concentration of 12 mg mL-1, for a period of 15, 30, 60, and 120 minutes. Subsequently, the eggs were washed and, after 180 hours of observation, the feed was added. The analysis of the chemical composition of the essential oil was performed by Gas Chromatography coupled to Mass Spectrometry. It was found that up to 180 hours of observation, the highest percentage of larval hatching occurred in eggs exposed to essential oil for 15 min (30%) and the lowest percentage in eggs exposed for 120 min ( less than 10%). After 180 hours, there was an increase in hatching in all treatments. The moisture content was 58.69%, the oil yield was 0.35%, and the main chemical constituents found were bicyclogermacrene and b-cariophylene. It was observed that the essential oil of Croton argyrophyllus, at the concentration evaluated, affects the hatching of Aedes aegypti larvae only in the absence of food.
{"title":"CHEMICAL COMPOSITION AND OVICIDA ACTIVITY OF THE ESSENTIAL OIL OF CROTON ARGYROPHYLLUS (EUPHORBIACEAE) LEAVES ABOUT AEDES AEGYPTI (DIPTERA: CULICIDAE","authors":"R. D. Costa, D. C. Silva, S. Gualberto, Paulo Sávio Damásio Da Silva, M. A. M. Costa","doi":"10.52571/ptq.v17.n36.2020.101_periodico36_pgs_85_99.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.101_periodico36_pgs_85_99.pdf","url":null,"abstract":"\u0000The control of Aedes aegypti, which transmits several arboviruses of importance to public health, has as strategies the use of synthetic insecticides, integrated with environmental control. Its control is mainly directed to the larvae and adult phases. The egg phase is difficult to control, as it has great resistance to environmental\u0000conditions. The objective of this work was to evaluate the ovicidal potential of the essential oil obtained from the leaves of Croton argyrophyllus, on Aedes aegypti, as well as to determine the moisture content, the yield, and its chemical composition. The eggs were exposed to the aqueous solution of the essential oil in 10% Tween 80,\u0000in the concentration of 12 mg mL-1, for a period of 15, 30, 60, and 120 minutes. Subsequently, the eggs were washed and, after 180 hours of observation, the feed was added. The analysis of the chemical composition of the essential oil was performed by Gas Chromatography coupled to Mass Spectrometry. It was found that up to 180 hours of observation, the highest percentage of larval hatching occurred in eggs exposed to essential oil for 15 min (30%) and the lowest percentage in eggs exposed for 120 min ( less than 10%). After 180 hours, there was an increase in hatching in all treatments. The moisture content was 58.69%, the oil yield was 0.35%, and the main chemical constituents found were bicyclogermacrene and b-cariophylene. It was observed that the essential oil of Croton argyrophyllus, at the concentration evaluated, affects the hatching of Aedes aegypti larvae only in the absence of food.","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46877740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.317_periodico36_pgs_302_314.pdf
Nurgiza F Ibrakova, G. G. Kutlugildina, Yuriy S. Zimin
Currently, the percentage of infections with invasive (parasitic) diseases is quite large; therefore, the treatment of helminthiases is an urgent problem in veterinary medicine. Parasitic worms inflict significant damage on animal husbandry, leading to the death of animals, shortage of meat, dairy products, and wool. The most common active ingredient in antihelmintics is praziquantel, which is well known as an effective broad-spectrum anthelmintic. At the same time, praziquantel has low solubility in water and a pronounced bitter taste, which represents a significant obstacle in developing liquid forms of drugs that are convenient for administration to animals. One way to solve these problems is the complexation of medicinal substances with various (natural and synthetic) compounds. In this regard, this paper aims to study the complexation of praziquantel with α-, β-, and -cyclodextrins in aqueous-alcoholic solutions. The studies were carried out by the method of ultraviolet spectroscopy. It was found that the addition of cyclodextrins to aqueous-alcoholic solutions of praziquantel leads to spectral changes indicating the presence of intermolecular interactions and complexation. The isomolar series method showed that in dilute solutions, praziquantel forms complex compounds with cyclodextrins 1:1, that is, one molecule of praziquantel falls on one molecule of α-, β- or y-cyclodextrin. The stability constants of the resulting complexes were calculated using the molar ratio method. It is shown that in the range of 296-316 K, the composition of complex compounds remains unchanged (1:1), and their stability decreases with increasing temperature. The study of the temperature dependences of the stability constants made it possible to determine the standard values of changes in the Gibbs energy, enthalpy, and complexation entropy.
{"title":"COMPLEXATION OF PRAZIQUANTEL WITH α-, β- AND y-CYCLODEXTRINS IN AQUEOUS-ALCOHOLIC SOLUTIONS","authors":"Nurgiza F Ibrakova, G. G. Kutlugildina, Yuriy S. Zimin","doi":"10.52571/ptq.v17.n36.2020.317_periodico36_pgs_302_314.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.317_periodico36_pgs_302_314.pdf","url":null,"abstract":"\u0000Currently, the percentage of infections with invasive (parasitic) diseases is quite large; therefore, the treatment of helminthiases is an urgent problem in veterinary medicine. Parasitic worms inflict significant damage on animal husbandry, leading to the death of animals, shortage of meat, dairy products, and wool. The most common active ingredient in antihelmintics is praziquantel, which is well known as an effective broad-spectrum anthelmintic. At the same time, praziquantel has low solubility in water and a pronounced bitter taste, which represents a significant obstacle in developing liquid forms of drugs that are convenient for administration to animals. One way to solve these problems is the complexation of medicinal substances with various (natural and synthetic) compounds. In this regard, this paper aims to study the complexation of praziquantel with α-, β-, and -cyclodextrins in aqueous-alcoholic solutions. The studies were carried out by the method of ultraviolet spectroscopy. It was found that the addition of cyclodextrins to aqueous-alcoholic solutions of praziquantel leads to spectral changes indicating the presence of intermolecular interactions and complexation. The isomolar series method showed that in dilute solutions, praziquantel forms complex compounds with cyclodextrins 1:1, that is, one molecule of praziquantel falls on one molecule of α-, β- or y-cyclodextrin. The stability constants of the resulting complexes were calculated using the molar ratio method. It is shown that in the range of 296-316 K, the composition of complex compounds remains unchanged (1:1), and their stability decreases with increasing temperature. The study of the temperature dependences of the stability constants made it possible to determine the standard values of changes in the Gibbs energy, enthalpy, and complexation entropy.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47537611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-20DOI: 10.52571/ptq.v17.n36.2020.860_periodico36_pgs_845_855.pdf
A. Sadritdinov, V. Chernova, M. Bazunova, E. Zakharova, V. Zakharov
The relevance of the issue under investigation is conditioned by an increase of the ecological burden on the environment due to the continuous increase of plastic waste, a significant proportion of polypropylene. One solution to this problem is the involvement of recycled polypropylene to obtain plastic products based on composites filled with rice husk. It makes it possible to reduce the prime cost of finished products, regulate their physical and mechanical properties, and reduce the volume of difficult-to-decompose synthetic polymers that end up in waste. The key property of polypropylene, which changes during its filling with rice husk, is moisture absorption, which contributes to a change in the strength characteristics of the polymer composite and accelerates its aging under the influence of environmental factors. In this regard, this research aims to identify the patterns of the influence of absorbed moisture and natural aging on the physical and mechanical properties of polymer composites based on recycled polypropylene filled with rice husk. The leading approach to the study of this issue is laboratory tests on the saturation of polymer composites with water of different temperatures and duration of exposure and testing materials during long-term natural aging under the influence of environmental factors. The key factor characterizing the change in the physical and mechanical properties of materials, in this case, is the elasticity modulus, elongation, and tensile stress at the break during stretching of the prototypes. The materials of the paper are of practical value for the processing of secondary thermoplastic polymers, as well as the development of biodegradable polymer composites.
{"title":"STRENGTH CHARACTERISTICS OF POLYMER COMPOSITES BASED ON RECYCLED POLYPROPYLENE FILLED WITH RICE HUSK DURING MOISTURE ABSORPTION AND NATURAL AGIN","authors":"A. Sadritdinov, V. Chernova, M. Bazunova, E. Zakharova, V. Zakharov","doi":"10.52571/ptq.v17.n36.2020.860_periodico36_pgs_845_855.pdf","DOIUrl":"https://doi.org/10.52571/ptq.v17.n36.2020.860_periodico36_pgs_845_855.pdf","url":null,"abstract":"\u0000The relevance of the issue under investigation is conditioned by an increase of the ecological burden on the environment due to the continuous increase of plastic waste, a significant proportion of polypropylene. One solution to this problem is the involvement of recycled polypropylene to obtain plastic products based on composites filled with rice husk. It makes it possible to reduce the prime cost of finished products, regulate their physical and mechanical properties, and reduce the volume of difficult-to-decompose synthetic polymers that end up in waste. The key property of polypropylene, which changes during its filling with rice husk, is moisture absorption, which contributes to a change in the strength characteristics of the polymer composite and accelerates its aging under the influence of environmental factors. In this regard, this research aims to identify the patterns of the influence of absorbed moisture and natural aging on the physical and mechanical properties of polymer composites based on recycled polypropylene filled with rice husk. The leading approach to the study of this issue is laboratory tests on the saturation of polymer composites with water of different temperatures and duration of exposure and testing materials during long-term natural aging under the influence of environmental factors. The key factor characterizing the change in the physical and mechanical properties of materials, in this case, is the elasticity modulus, elongation, and tensile stress at the break during stretching of the prototypes. The materials of the paper are of practical value for the processing of secondary thermoplastic polymers, as well as the development of biodegradable polymer composites.\u0000","PeriodicalId":45103,"journal":{"name":"Periodico Tche Quimica","volume":" ","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48595131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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