Pub Date : 2019-12-18DOI: 10.35666/ghtbh.2019.53.02
Calibration baths are widely used in many laboratories worldwide for the calibration of thermometers by comparison. They come in different shapes and sizes and use different media (water, alcohol, silicon oil etc.), but a certain nonuniformity of theused media is always present. During precision temperature measurements, uniformity (homogeneity and temporal stability) of a calibration bath is of the utmost importance since its contribution to total measurement uncertainty is the largest. The temperature gradient can be described as a change of temperature at different positions inside the bath working volume. Temporal temperature stability depends on many factors such as: the bath temperature, control system, bath construction and the flow of the used media inside the bath, just to name a few. In this paper, we investigate uniformity of a cylindrical calibration bath. Homogeneity is determined by measurement of axial and radial temperature gradient inside the bath. Stability is examined by observation of the change in temperature reading during certain period of time. The obtained results are compared with manufacturer specification and can be used for determination of calibration bath contribution to total measurement uncertainty during calibration of thermometers.
{"title":"Calibration bath uncertainty in precision temperature measurements","authors":"","doi":"10.35666/ghtbh.2019.53.02","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.53.02","url":null,"abstract":"Calibration baths are widely used in many laboratories worldwide for the calibration of thermometers by comparison. They come in different shapes and sizes and use different media (water, alcohol, silicon oil etc.), but a certain nonuniformity of theused media is always present. During precision temperature measurements, uniformity (homogeneity and temporal stability) of a calibration bath is of the utmost importance since its contribution to total measurement uncertainty is the largest. The temperature gradient can be described as a change of temperature at different positions inside the bath working volume. Temporal temperature stability depends on many factors such as: the bath temperature, control system, bath construction and the flow of the used media inside the bath, just to name a few. In this paper, we investigate uniformity of a cylindrical calibration bath. Homogeneity is determined by measurement of axial and radial temperature gradient inside the bath. Stability is examined by observation of the change in temperature reading during certain period of time. The obtained results are compared with manufacturer specification and can be used for determination of calibration bath contribution to total measurement uncertainty during calibration of thermometers.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"20 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91011204","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 : 2019-12-18DOI: 10.35666/ghtbh.2019.53.03
Tahirović
The phenolic content and antioxidant activity of Sorbus aucuparia L., Sorbus aria (L.) Crantz and Sorbus austriaca (Beck) Hedlund leaves and fruit were investigated. The quantification of total phenolics, flavonoids and phenolic acids was performed using the Folin–Ciocalteu, Dowd and Arnow methods, respectively. The antioxidant activity of the extracts was evaluated using DPPH, TEAC and FRAP methods with Trolox as a standard. Leaves had a higher content of phenolic compounds and antioxidant activity than the fruits for all species. The highest content of phenolics (76.11 mg gallic acid equivalents (GAE)/g plant), flavonoids (15.86 mg rutin equivalents (RE)/g plant) and phenolic acids (44.54 mg caffeic acid equivalents (CAE)/g plant) was determined for S. austriaca leaves. Sorbus austriaca fruit had the highest content of phenolics (13.21 mg GAE/g plant), flavonoids (1.82 mg RE/g plant) and S. aucuparia fruit had the highest content of phenolic acids (9.05 mg CAE/g plant). The antioxidant activity was in the range: DPPH=38.42–274.52 μmol Trolox equivalents (TE)/g plant; TEAC=43.23–403.02 μmol TE/g plant; FRAP=47.13–706.96 μmol TE/g plant. The highest values of antioxidant activity were found for S. austriaca leaf and fruit extracts while the lowest values were determined for S. aucuparia leaves and S. aria fruit. The antioxidant activity was highly correlated with total phenolics and phenolic acids.
{"title":"Phenolics content and antioxidant activity of three Sorbus species","authors":"Tahirović","doi":"10.35666/ghtbh.2019.53.03","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.53.03","url":null,"abstract":"The phenolic content and antioxidant activity of Sorbus aucuparia L., Sorbus aria (L.) Crantz and Sorbus austriaca (Beck) Hedlund leaves and fruit were investigated. The quantification of total phenolics, flavonoids and phenolic acids was performed using the Folin–Ciocalteu, Dowd and Arnow methods, respectively. The antioxidant activity of the extracts was evaluated using DPPH, TEAC and FRAP methods with Trolox as a standard. Leaves had a higher content of phenolic compounds and antioxidant activity than the fruits for all species. The highest content of phenolics (76.11 mg gallic acid equivalents (GAE)/g plant), flavonoids (15.86 mg rutin equivalents (RE)/g plant) and phenolic acids (44.54 mg caffeic acid equivalents (CAE)/g plant) was determined for S. austriaca leaves. Sorbus austriaca fruit had the highest content of phenolics (13.21 mg GAE/g plant), flavonoids (1.82 mg RE/g plant) and S. aucuparia fruit had the highest content of phenolic acids (9.05 mg CAE/g plant). The antioxidant activity was in the range: DPPH=38.42–274.52 μmol Trolox equivalents (TE)/g plant; TEAC=43.23–403.02 μmol TE/g plant; FRAP=47.13–706.96 μmol TE/g plant. The highest values of antioxidant activity were found for S. austriaca leaf and fruit extracts while the lowest values were determined for S. aucuparia leaves and S. aria fruit. The antioxidant activity was highly correlated with total phenolics and phenolic acids.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"4 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78643814","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 : 2019-12-18DOI: 10.35666/ghtbh.2019.53.04
The main aim of this preliminary study was to investigate the presence of potentially toxic compounds (methanol, hydrocyanic acid and urea) in homemade fruit spirits produced in different parts of Bosnia and Herzegovina. A total of 15 samples of 8 different fruit spirits were analyzed (apple, apricot, cherry, grape, pear, plum, quince and juniper). Content of hydrocyanic acid was higher than maximum permissible level in 5 out of 15 samples. In general, the average content of methanol was higher in samples from Bosnia comparing to the samples from Herzegovina (874.62 vs. 563.99 g/hL of pure alcohol), but still was lower than maximum concentration proposed by national regulation (1200 g/hLof pure alcohol for fruit spirits and 1000 g/hL of pure alcohol for grape spirit) except for one grape spirit sample (1162.2 g/hL of pure alcohol). Urea was detected in all analyzed samples (5.819 to 77.82 mg/L) with the average concentration of 37.95 mg/L. Since this is, to our knowledge, the firststudy that included the chemical analysis of homemade spirits in BiH, these results are of great importance for the further research.
{"title":"Toxic compounds in homemade spirits in Bosnia and Herzegovina: A pilot study","authors":"","doi":"10.35666/ghtbh.2019.53.04","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.53.04","url":null,"abstract":"The main aim of this preliminary study was to investigate the presence of potentially toxic compounds (methanol, hydrocyanic acid and urea) in homemade fruit spirits produced in different parts of Bosnia and Herzegovina. A total of 15 samples of 8 different fruit spirits were analyzed (apple, apricot, cherry, grape, pear, plum, quince and juniper). Content of hydrocyanic acid was higher than maximum permissible level in 5 out of 15 samples. In general, the average content of methanol was higher in samples from Bosnia comparing to the samples from Herzegovina (874.62 vs. 563.99 g/hL of pure alcohol), but still was lower than maximum concentration proposed by national regulation (1200 g/hLof pure alcohol for fruit spirits and 1000 g/hL of pure alcohol for grape spirit) except for one grape spirit sample (1162.2 g/hL of pure alcohol). Urea was detected in all analyzed samples (5.819 to 77.82 mg/L) with the average concentration of 37.95 mg/L. Since this is, to our knowledge, the firststudy that included the chemical analysis of homemade spirits in BiH, these results are of great importance for the further research.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"44 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87719596","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 : 2019-12-18DOI: 10.35666/ghtbh.2019.53.06
Water is one of the most important constituents of food, very important to be accurately quantified. Furthermore, water content affects the stability and shelf life of food. The evaluation of most chemical parameters is based on dry mass and many methods use heating which result in losing all volatile compounds, including water. Also, it is much harder to extract all of water if we have a complex matrix. Regarding this, the aim of this study was to determine water content in different infant formula by various methods. For examination of water content in three different types of infant formula three different techniques were used (oven sample processor, drying oven and halogen drying) and compared to classical Karl Fischer titration with two different solvents. Each sample was measured in ten probes, and classical Karl Fischer titration was used as a reference. The results showed that the reference method was the best regarding speed of measurement, amount of sample needed and obtained water contents (3.01- 4.35%), followed by Karl Fischer in boiling methanol (2.80-4.30), oven sample processor (2.96-4.23%), halogen drying (2.74-4.03%) and drying oven (2.38-3.52). Methods using heating could not remove all water from the sample within a reasonable time.
{"title":"Determination of water content in infant formula","authors":"","doi":"10.35666/ghtbh.2019.53.06","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.53.06","url":null,"abstract":"Water is one of the most important constituents of food, very important to be accurately quantified. Furthermore, water content affects the stability and shelf life of food. The evaluation of most chemical parameters is based on dry mass and many methods use heating which result in losing all volatile compounds, including water. Also, it is much harder to extract all of water if we have a complex matrix. Regarding this, the aim of this study was to determine water content in different infant formula by various methods. For examination of water content in three different types of infant formula three different techniques were used (oven sample processor, drying oven and halogen drying) and compared to classical Karl Fischer titration with two different solvents. Each sample was measured in ten probes, and classical Karl Fischer titration was used as a reference. The results showed that the reference method was the best regarding speed of measurement, amount of sample needed and obtained water contents (3.01- 4.35%), followed by Karl Fischer in boiling methanol (2.80-4.30), oven sample processor (2.96-4.23%), halogen drying (2.74-4.03%) and drying oven (2.38-3.52). Methods using heating could not remove all water from the sample within a reasonable time.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"123 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88629523","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 : 2019-06-30DOI: 10.35666/ghtbh.2019.52.01
F. B. G. S. B. O. J. B. H. S. B. B. A. B. Korać, S. Korać, F. Korać
Due to a growing awareness of environmental protection, an interest in replacing toxic corrosion inhibitors with more environmentally acceptable alternatives is also growing. Chromates, as one of the best inhibitors, have been eliminated as technically viable inhibitors because of their high toxicity, and the use of polyphosphates has diminished as they disrupt the balance in the Plantae kingdom. The emphasis is on exploration and testing of organic compounds that can be obtained from plant material. Rosemary extracts (leaf and flower) have been shown to have inhibitory activity on iron corrosion in 3% NaCl and seawater. Corrosion rate values show that rosemary flower extracts are better inhibitors of corrosion than the leaf extracts and that the maximum inhibitory protection has not been achieved in the range of tested concentrations.
{"title":"Inhibition of Iron Corrosion in Seawater Using Rosemary Extracts (Rosmarinusofficinalis L.)","authors":"F. B. G. S. B. O. J. B. H. S. B. B. A. B. Korać, S. Korać, F. Korać","doi":"10.35666/ghtbh.2019.52.01","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.52.01","url":null,"abstract":"Due to a growing awareness of environmental protection, an interest in replacing toxic corrosion inhibitors with more environmentally acceptable alternatives is also growing. Chromates, as one of the best inhibitors, have been eliminated as technically viable inhibitors because of their high toxicity, and the use of polyphosphates has diminished as they disrupt the balance in the Plantae kingdom. The emphasis is on exploration and testing of organic compounds that can be obtained from plant material. Rosemary extracts (leaf and flower) have been shown to have inhibitory activity on iron corrosion in 3% NaCl and seawater. Corrosion rate values show that rosemary flower extracts are better inhibitors of corrosion than the leaf extracts and that the maximum inhibitory protection has not been achieved in the range of tested concentrations.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"11 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83146976","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 : 2019-06-30DOI: 10.35666/ghtbh.2019.52.04
This paper considers the inhibition effect of Aloe Vera on the selected aluminium alloys in 10 % sulfuric acid and 3 % sodium chloride solutions at room temperature, using methods of potentiodynamic polarisation and cyclic voltammetry. The study involved as-cast and heat-treated 2xxx alloys, with the scanning speed of 1mV/s for linear polarisation and 50 mV/s for cyclic voltammetry. The various constant potential was applied for each tested alloy. Polarisation results indicate that the transpassivation occurs in an acid medium in case of each alloy. The obtained results indicate that Aloe vera extract acts as a cathodic inhibitor.
{"title":"Investigation of Inhibitory Effect of the Aloe Vera Extract on Corrosion of Aluminium Alloys","authors":"","doi":"10.35666/ghtbh.2019.52.04","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.52.04","url":null,"abstract":"This paper considers the inhibition effect of Aloe Vera on the selected aluminium alloys in 10 % sulfuric acid and 3 % sodium chloride solutions at room temperature, using methods of potentiodynamic polarisation and cyclic voltammetry. The study involved as-cast and heat-treated 2xxx alloys, with the scanning speed of 1mV/s for linear polarisation and 50 mV/s for cyclic voltammetry. The various constant potential was applied for each tested alloy. Polarisation results indicate that the transpassivation occurs in an acid medium in case of each alloy. The obtained results indicate that Aloe vera extract acts as a cathodic inhibitor.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"21 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78962008","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 : 2019-01-01DOI: 10.35666/ghtbh.2019.52.02
P. Ba, B. Fá
In modern world, hyperlipidemia is the most common disorder mainly caused by lifestyle habits and the major cause of cardiovascular, coronary and atherosclerotic changes. Such disorder is characterized by abnormally elevated levels of any or all lipids or lipoproteins in the blood. A wide range of drugs are available for the treatment of hyperlipidemia, class of antihyperlipidemic drugs, but such drug-therapies are carried out with presence of various side effects. In the last decades, different in vitro and in vivo research have been conducted to confirm the therapeutic effects of various phytochemical agents that overcome the side effects caused by synthetic drugs. According to Ayurvedic recommendations and experimental studies, numerous phytochemical agents have been reported to possess different antihyperlipidemic properties. One of the most studied phytochemical agent - curcumin, herbal polyphenol and active ingredient which can be extracted from the powder rhizome of the plant Curcuma longa, has been reported to possess a wide range of pharmacological properties such as antimicrobial, antioxidative, antiinflammatory and anticancer property. Recent studies also suggests curcumin as potential lipid lowering candidate in treatment of hyperlipidemia. The aim of this review is to present and discuss phytochemistry, molecular mechanism of hypolipidemic activity of curcumin, demonstrating its importance as potential therapy for the treatment of hyperlipidemia.
{"title":"Curcumin: Phytochemical Therapy in the Treatment of Hyperlipidemia","authors":"P. Ba, B. Fá","doi":"10.35666/ghtbh.2019.52.02","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.52.02","url":null,"abstract":"In modern world, hyperlipidemia is the most common disorder mainly caused by lifestyle habits and the major cause of cardiovascular, coronary and atherosclerotic changes. Such disorder is characterized by abnormally elevated levels of any or all lipids or lipoproteins in the blood. A wide range of drugs are available for the treatment of hyperlipidemia, class of antihyperlipidemic drugs, but such drug-therapies are carried out with presence of various side effects. In the last decades, different in vitro and in vivo research have been conducted to confirm the therapeutic effects of various phytochemical agents that overcome the side effects caused by synthetic drugs. According to Ayurvedic recommendations and experimental studies, numerous phytochemical agents have been reported to possess different antihyperlipidemic properties. One of the most studied phytochemical agent - curcumin, herbal polyphenol and active ingredient which can be extracted from the powder rhizome of the plant Curcuma longa, has been reported to possess a wide range of pharmacological properties such as antimicrobial, antioxidative, antiinflammatory and anticancer property. Recent studies also suggests curcumin as potential lipid lowering candidate in treatment of hyperlipidemia. The aim of this review is to present and discuss phytochemistry, molecular mechanism of hypolipidemic activity of curcumin, demonstrating its importance as potential therapy for the treatment of hyperlipidemia.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"41 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73446480","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 : 2019-01-01DOI: 10.35666/ghtbh.2019.52.03
Movre Šapić
The aim of this research is to detect zwittterionic structure of the aspartic acid and confirm the experimental spectra with quantum chemical calculations. The experimental IR and Raman spectra of aspartic acid powder show no vibrational bands of OH and NH stretching in expected spectral region. We assume that zwitterionic structure of aspartic acid is responsible for lowering the frequencies of these vibrations. An extensive experimental and computational research supports this assumption. Our DFT calculation strongly suggests the need for the dielectric environment in order to stabilize the zwitterionic structure of a single molecule. The network of intermolecular hydrogen bonding between aspartic acid molecules provides this dielectric environment. The DFT quantum mechanical calculations corroborate this assumption by optimizing a four-member group of molecules, which also gives an explanation of broad IR spectrum lines.
{"title":"Experimental and theoretical study of Aspartic acid","authors":"Movre Šapić","doi":"10.35666/ghtbh.2019.52.03","DOIUrl":"https://doi.org/10.35666/ghtbh.2019.52.03","url":null,"abstract":"The aim of this research is to detect zwittterionic structure of the aspartic acid and confirm the experimental spectra with quantum chemical calculations. The experimental IR and Raman spectra of aspartic acid powder show no vibrational bands of OH and NH stretching in expected spectral region. We assume that zwitterionic structure of aspartic acid is responsible for lowering the frequencies of these vibrations. An extensive experimental and computational research supports this assumption. Our DFT calculation strongly suggests the need for the dielectric environment in order to stabilize the zwitterionic structure of a single molecule. The network of intermolecular hydrogen bonding between aspartic acid molecules provides this dielectric environment. The DFT quantum mechanical calculations corroborate this assumption by optimizing a four-member group of molecules, which also gives an explanation of broad IR spectrum lines.","PeriodicalId":40710,"journal":{"name":"Glasnik Hemicara i Tehnologa Bosne i Hercegovine","volume":"45 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74917060","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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