We studied the critical properties of flexible polymers, modelled by self-avoiding random walks, in good solvents and homogeneous environments. By applying the PERM Monte Carlo simulation method, we generated the polymer chains on the square and the simplecubic lattice of the maximal length of N=2000 steps.We enumerated approximately the number of different polymer chain configurations of length N,and analysed its asymptotic behaviour (for large N), determined by the connectivity constant μ and the entropic critical exponent γ. Also, we studied the behaviour of the set of effective critical exponents 휈푁, governing the end-to-end distance of a polymer chain of length N. We have established that in two dimensions 휈푁monotonically increases with N, whereas in three dimensions itmonotonically decreases when Nincreases. Values of 휈푁, obtained for both spatial dimensions have been extrapolated in the range of very long chains.In the end, we discuss and compare our results to those obtained previously for polymers on Euclidean lattices.
{"title":"MONTE CARLO SIMULATIONS OF A POLYMER CHAIN MODEL ON EUCLIDEAN LATTICES","authors":"I. Živić, D. Marčetić, Sunčica Elezović Hadžić","doi":"10.7251/comen1902167z","DOIUrl":"https://doi.org/10.7251/comen1902167z","url":null,"abstract":"We studied the critical properties of flexible polymers, modelled by self-avoiding random walks, in good solvents and homogeneous environments. By applying the PERM Monte Carlo simulation method, we generated the polymer chains on the square and the simplecubic lattice of the maximal length of N=2000 steps.We enumerated approximately the number of different polymer chain configurations of length N,and analysed its asymptotic behaviour (for large N), determined by the connectivity constant μ and the entropic critical exponent γ. Also, we studied the behaviour of the set of effective critical exponents 휈푁, governing the end-to-end distance of a polymer chain of length N. We have established that in two dimensions 휈푁monotonically increases with N, whereas in three dimensions itmonotonically decreases when Nincreases. Values of 휈푁, obtained for both spatial dimensions have been extrapolated in the range of very long chains.In the end, we discuss and compare our results to those obtained previously for polymers on Euclidean lattices.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86045025","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}
In present paper, studied were the dispersion-flocculation behaviour of the primary natural raw „clay samples” from Omarska mine (Republic of Srpska, Bosnia and Herzegovina). Namely, our previous results showed that during the processing of iron ore in the Omarska mine, large quantities of fine sized (15μm) waste sludge, with relatively high Fe concentrations, were generated. Sludge samples are composed of major goethite and quartz, less clay minerals, and minor magnetite and todorokite. Selective flocculation is one of the methods that can be applied for the separation of fine class iron minerals from impurities and depends on the individual components of the sludge and their behaviour. This paper presents part of the research of the individual components of the sludge. The „clay samples” are composed of major quartz and clay minerals, which dominate over minor contents of feldspars, amphiboles, goethite and hematite. The clay minerals were identified as mostly illite-sericite which prevails over kaolinite, and with chlorites which appears only sporadically. The dispersion-flocculation behaviour was studied by settling and flocculation experiments and Zeta potential measurements. A three different dispersants (sodium hexametaphosphate, sodium-pyrophosphate and sodiumsilicate), and anionic and non-ionic polyacrylamide (PAM) flocculants were used. It was established that the best results were achieved with sodium-hexametaphosphate (1000 g/t) and anionic A100 PAM.
{"title":"THE DISPERSION-FLOCCULATION BEHAVIOUR OF THE NATURAL RAW CLAY SAMPLES FROM OMARSKA MINE","authors":"Ljiljana Tankosić, S. Sredić, P. Tančić, Z. Nedić","doi":"10.7251/comen1901071t","DOIUrl":"https://doi.org/10.7251/comen1901071t","url":null,"abstract":"In present paper, studied were the dispersion-flocculation behaviour of the primary natural raw „clay samples” from Omarska mine (Republic of Srpska, Bosnia and Herzegovina). Namely, our previous results showed that during the processing of iron ore in the Omarska mine, large quantities of fine sized (15μm) waste sludge, with relatively high Fe concentrations, were generated. Sludge samples are composed of major goethite and quartz, less clay minerals, and minor magnetite and todorokite. Selective flocculation is one of the methods that can be applied for the separation of fine class iron minerals from impurities and depends on the individual components of the sludge and their behaviour. This paper presents part of the research of the individual components of the sludge. The „clay samples” are composed of major quartz and clay minerals, which dominate over minor contents of feldspars, amphiboles, goethite and hematite. The clay minerals were identified as mostly illite-sericite which prevails over kaolinite, and with chlorites which appears only sporadically. The dispersion-flocculation behaviour was studied by settling and flocculation experiments and Zeta potential measurements. A three different dispersants (sodium hexametaphosphate, sodium-pyrophosphate and sodiumsilicate), and anionic and non-ionic polyacrylamide (PAM) flocculants were used. It was established that the best results were achieved with sodium-hexametaphosphate (1000 g/t) and anionic A100 PAM.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86548201","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}
I. Ristić, M. Jotanović, T. Erceg, L. Nikolić, S. Cakić, V. Mićić, Stefan M. Pavlović, S. Begić
The consequence of drastic reduction in fossil fuel reserves has forced the scientific community to find and develop new ways to exploit renewable resources and optimize the process of polymer materials production. The aim is to obtain applicable polymer whose complete life cycle is set in ecological framework. Poly(lactide) (PLA) meets these requirements as biodegradable polyester whose monomer is derived from the plant feedstock containing carbohydrates. PLA could be prepared using the different synthesis routes, but from the point of energy saving, as well as environmental protection, the microwave synthesis of PLA is the best solution. In this work, poly(L-lactide) were synthesized in microwave reactor. Reaction time was varied, while the other parameters of the synthesis were constant. The structures of obtained polymers were confirmed by Fourier – transform infrared spectroscopy (FT-IR). For determination of molar masses of poly(L-lactide) samples, the gel permeation chromatography (GPC) was applied. Thermal properties were investigated by differential scanning calorimetry (DSC).
{"title":"THE INFLUENCE OF REACTION TIME ON THE PROPERTIES OF MICROWAVE SYNTHESIZED POLY(LACTIDE)","authors":"I. Ristić, M. Jotanović, T. Erceg, L. Nikolić, S. Cakić, V. Mićić, Stefan M. Pavlović, S. Begić","doi":"10.7251/comen1901056r","DOIUrl":"https://doi.org/10.7251/comen1901056r","url":null,"abstract":"The consequence of drastic reduction in fossil fuel reserves has forced the scientific community to find and develop new ways to exploit renewable resources and optimize the process of polymer materials production. The aim is to obtain applicable polymer whose complete life cycle is set in ecological framework. Poly(lactide) (PLA) meets these requirements as biodegradable polyester whose monomer is derived from the plant feedstock containing carbohydrates. PLA could be prepared using the different synthesis routes, but from the point of energy saving, as well as environmental protection, the microwave synthesis of PLA is the best solution. In this work, poly(L-lactide) were synthesized in microwave reactor. Reaction time was varied, while the other parameters of the synthesis were constant. The structures of obtained polymers were confirmed by Fourier – transform infrared spectroscopy (FT-IR). For determination of molar masses of poly(L-lactide) samples, the gel permeation chromatography (GPC) was applied. Thermal properties were investigated by differential scanning calorimetry (DSC).","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89364983","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}
Jovana Z Milanovic, Matea Korica, T. Nikolić, M. Kostić
In this paper, the principles of the action of the selective (NaIO4 and 2,2,6,6-tetramethylpiperidine-1-oxyl-TEMPO radical) and non-selective (H2O2 and KMnO4) oxidation agents on cellulose are presented. Their importance in modifying the existing properties or giving new properties to cellulosic materials, as well as examples of their applications are also given. The oxidation product - oxycellulose presents the base for obtaining a wide range of materials for special applications. Particularly, the influence of TEMPO-mediated oxidation on natural and man-made cellulosic fibers is presented, with a detailed overview on the type and quantity of introduced functional groups, changes in structure, sorption and mechanical properties. Also, we described the use of TEMPOmediated oxidation for the production of cellulosic nano-materials in the form of dispersions, particles and films, as well as the potential application of these nano-structural materials.
{"title":"OXYCELLULOSE – MATERIAL FOR NEW APPLICATION AREAS","authors":"Jovana Z Milanovic, Matea Korica, T. Nikolić, M. Kostić","doi":"10.7251/comen1901006m","DOIUrl":"https://doi.org/10.7251/comen1901006m","url":null,"abstract":"In this paper, the principles of the action of the selective (NaIO4 and 2,2,6,6-tetramethylpiperidine-1-oxyl-TEMPO radical) and non-selective (H2O2 and KMnO4) oxidation agents on cellulose are presented. Their importance in modifying the existing properties or giving new properties to cellulosic materials, as well as examples of their applications are also given. The oxidation product - oxycellulose presents the base for obtaining a wide range of materials for special applications. Particularly, the influence of TEMPO-mediated oxidation on natural and man-made cellulosic fibers is presented, with a detailed overview on the type and quantity of introduced functional groups, changes in structure, sorption and mechanical properties. Also, we described the use of TEMPOmediated oxidation for the production of cellulosic nano-materials in the form of dispersions, particles and films, as well as the potential application of these nano-structural materials.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89816539","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}
S. Janković, Dragana Milisavić, Tanja Okolić, Dijana Jelić
Zinc oxide is a highly applicable semiconductor material. Wide applica-tion of this nanomaterial is connected to wide spectrum of energy band gap, high bond en-ergy, great thermal conductivity, but also with its non-toxicity, antibacterial activity, bio-compatibility and biodegradability characteristics. The aim of this paper is synthesis and characterization of silver doped ZnO nanoparticles (ZnO:Ag NP) using sol-gel method. Ob-tained samples of silver doped ZnO nanoparticles were characterized by following tech-niques: Fourier-transform infrared spectroscopy (FTIR), UV/VIS spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spec-troscopy (EDX). Efficiency of provided synthesis method was examined by FTIR spectros-copy. XRD determined the purity and crystallinity, and wurtzite structure of synthesized material. Surface morphology and the effect of doping were examined using SEM and EDX characterization methods. Results showed better conductivity after doping ZnO nanoparti-cles with silver. SEM micrographs showed ZnO:Ag NP in the form of nanorods with a par-ticle average size of 6 nm.
{"title":"SYNTHESIS OF ZnO-Аg NANOPARTICLES BY SOL-GEL METHOD","authors":"S. Janković, Dragana Milisavić, Tanja Okolić, Dijana Jelić","doi":"10.7251/comen1901022j","DOIUrl":"https://doi.org/10.7251/comen1901022j","url":null,"abstract":"Zinc oxide is a highly applicable semiconductor material. Wide applica-tion of this nanomaterial is connected to wide spectrum of energy band gap, high bond en-ergy, great thermal conductivity, but also with its non-toxicity, antibacterial activity, bio-compatibility and biodegradability characteristics. The aim of this paper is synthesis and characterization of silver doped ZnO nanoparticles (ZnO:Ag NP) using sol-gel method. Ob-tained samples of silver doped ZnO nanoparticles were characterized by following tech-niques: Fourier-transform infrared spectroscopy (FTIR), UV/VIS spectrophotometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spec-troscopy (EDX). Efficiency of provided synthesis method was examined by FTIR spectros-copy. XRD determined the purity and crystallinity, and wurtzite structure of synthesized material. Surface morphology and the effect of doping were examined using SEM and EDX characterization methods. Results showed better conductivity after doping ZnO nanoparti-cles with silver. SEM micrographs showed ZnO:Ag NP in the form of nanorods with a par-ticle average size of 6 nm.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84911520","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}
N. Trtić, R. Arbutina, O. Janković, V. Mirjanić, V. Veselinović
Dental erosions are defined as an irreversible loss of hard dental tissue caused by long-lasting and repetitive acid action, which dissolves the surface layer of hydroxyapatite crystal structure and fluorapatite, and the aggressive noxis not being created by the bacteria. Dental erosions can also be classified as occupational diseases. People who taste wine or carbonated drinks on a daily basis, as well as the people who are professionally engaged in swimming can spot this type of defect on their own teeth. Evaporation of industrial acids in battery factories, sanitary materials, or crystalline glass can also lead to dental erosions. Aim: The purpose of this study was to determine the frequency of dental erosion in patients under antihypertensive therapy and compare them with the frequency of dental erosion in patients who did not take the same therapy. Material and method: This research involved 62 respondents, aged from 20 to 70. Patients were classified into two groups, the experimental group with 31 patients being on a therapy with antihypertensive medications for more than 5 years, and the other one, control group, with 31 patients not being on the mentioned therapy. The subjective dental anamnesis obtained from the patients was noted along with tooth status, soft tissue intraoral examination and the degree of erosive changes according to BEWE index (Basic Erosive Wear Examination). Results: Comparing the statistical significance in difference between erosive index value of all teeth, there is obvious statistical difference of the average value. In the experimental group (p0.05), higher values of tooth erosion index were noted in comparison with the control group. The average value in the experimental group is 2.25, while in the control group it is 1.37. Conclusion: Erosive lesions are present in both experimental and control group respondents, with dental erosion being more explicit with patients who use antihypertensive medications.
{"title":"CLINICAL MANIFESTATION AND INCIDENCE OF DENTAL ENAMEL EROSION IN PATIENTS UNDER ANTIHYPERTENSIVE THERAPY","authors":"N. Trtić, R. Arbutina, O. Janković, V. Mirjanić, V. Veselinović","doi":"10.7251/comen1901093a","DOIUrl":"https://doi.org/10.7251/comen1901093a","url":null,"abstract":"Dental erosions are defined as an irreversible loss of hard dental tissue caused by long-lasting and repetitive acid action, which dissolves the surface layer of hydroxyapatite crystal structure and fluorapatite, and the aggressive noxis not being created by the bacteria. Dental erosions can also be classified as occupational diseases. People who taste wine or carbonated drinks on a daily basis, as well as the people who are professionally engaged in swimming can spot this type of defect on their own teeth. Evaporation of industrial acids in battery factories, sanitary materials, or crystalline glass can also lead to dental erosions. Aim: The purpose of this study was to determine the frequency of dental erosion in patients under antihypertensive therapy and compare them with the frequency of dental erosion in patients who did not take the same therapy. Material and method: This research involved 62 respondents, aged from 20 to 70. Patients were classified into two groups, the experimental group with 31 patients being on a therapy with antihypertensive medications for more than 5 years, and the other one, control group, with 31 patients not being on the mentioned therapy. The subjective dental anamnesis obtained from the patients was noted along with tooth status, soft tissue intraoral examination and the degree of erosive changes according to BEWE index (Basic Erosive Wear Examination). Results: Comparing the statistical significance in difference between erosive index value of all teeth, there is obvious statistical difference of the average value. In the experimental group (p0.05), higher values of tooth erosion index were noted in comparison with the control group. The average value in the experimental group is 2.25, while in the control group it is 1.37. Conclusion: Erosive lesions are present in both experimental and control group respondents, with dental erosion being more explicit with patients who use antihypertensive medications.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"107 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78347788","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}
S. Pelemiš, D. Mirjanić, D. Đeorđić, Ozren Petrović
Nanotehnology applied to biomedicine has an important place in research of nanomaterials. Size of nanomaterials particles is similar to the size of biological molecules and structures, a conclusion can be drawn that the application of nanomaterials in vivo and in vitro biomedical researches is possible. This paper is a short overview of medical applications of different nanomaterials such as carbon nanotubes, graphene, quantum dots, nanocapsules etc. The main nanocarriers systems such as liposomes, micelles and dendrimers also will be presented. Today, we are witnessing the great boom of magnetic particles as essential components in several areas of medical practice. The great advantages of using nanomaterials in biomedical areas lies in their ability to operate on the same small scale as all the intimate biochemical functions involved in the growth, development and ageing of the human body. Nano-pharamceuticals reveal enormous potential in drug delivery as carrier for spatial and temporal delivery of bioactive components and diagnostics. Additionally, it also provides smart materials for tissue engineering. This discipline is now well-established for drug delivery, diagnostics, prognostic and treatment of diseases through its nanoengineered tools.
{"title":"SOME OF BENEFITS NANOMATERIALS APPLICATIONS IN MEDICINE","authors":"S. Pelemiš, D. Mirjanić, D. Đeorđić, Ozren Petrović","doi":"10.7251/comen1901028p","DOIUrl":"https://doi.org/10.7251/comen1901028p","url":null,"abstract":"Nanotehnology applied to biomedicine has an important place in research of nanomaterials. Size of nanomaterials particles is similar to the size of biological molecules and structures, a conclusion can be drawn that the application of nanomaterials in vivo and in vitro biomedical researches is possible. This paper is a short overview of medical applications of different nanomaterials such as carbon nanotubes, graphene, quantum dots, nanocapsules etc. The main nanocarriers systems such as liposomes, micelles and dendrimers also will be presented. Today, we are witnessing the great boom of magnetic particles as essential components in several areas of medical practice. The great advantages of using nanomaterials in biomedical areas lies in their ability to operate on the same small scale as all the intimate biochemical functions involved in the growth, development and ageing of the human body. Nano-pharamceuticals reveal enormous potential in drug delivery as carrier for spatial and temporal delivery of bioactive components and diagnostics. Additionally, it also provides smart materials for tissue engineering. This discipline is now well-established for drug delivery, diagnostics, prognostic and treatment of diseases through its nanoengineered tools.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75813302","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}
Ž. Gagić, Irena Kasagić Vujanović, Nina Okuka, D. Knezevic
In this paper, presented are the results of quality control of distilled water used for the reconstitution of powders for oral suspension usually intended for pediatric population. By reviewing the legislation, there is no clearly defined shelf life and storage instruction for this type of water. The conducted analyses confirmed that some pharmacies on the territory of Bosnia and Herzegovina use technical distilled water (water for accumulators, iron and antifreeze dilution), but also distilled water that does not meet quality requirements prescribed by European Pharmacopoeia. The tested water samples did not have adequately labeled packaging (production time and shelf life). The results showed that out of a total of 10 samples, 2 had conductivity greater than permissible, 3 had an exceeded limit for heavy metals, and 2 of the samples showed the presence of oxidisable substances. Out of all tested samples, only one sample met microbiological criteria for purified water. Based on the results of these analyses, it can be assumed that in many pharmacies around the country, inadequate distilled water is used which could endanger the stability of the pharmaceutical preparation and the safety of the patient. Bearing in mind that antibiotic oral suspensions are prescribed from the age of the infant, and that a large number of children consume these products for a long period due to frequent infections, the question arises as to whether prepared drugs accomplish their purpose and whether pharmacists are sufficiently aware of the importance of the quality of this type of water?
{"title":"QUALITY CONTROL OF DISTILLED WATER USED FOR RECONSTITUTION OF POWDERS FOR ORAL SUSPENSION IN PHARMACIES ON THE TERRITORY OF BOSNIA AND HERZEGOVINA","authors":"Ž. Gagić, Irena Kasagić Vujanović, Nina Okuka, D. Knezevic","doi":"10.7251/comen1901047v","DOIUrl":"https://doi.org/10.7251/comen1901047v","url":null,"abstract":"In this paper, presented are the results of quality control of distilled water used for the reconstitution of powders for oral suspension usually intended for pediatric population. By reviewing the legislation, there is no clearly defined shelf life and storage instruction for this type of water. The conducted analyses confirmed that some pharmacies on the territory of Bosnia and Herzegovina use technical distilled water (water for accumulators, iron and antifreeze dilution), but also distilled water that does not meet quality requirements prescribed by European Pharmacopoeia. The tested water samples did not have adequately labeled packaging (production time and shelf life). The results showed that out of a total of 10 samples, 2 had conductivity greater than permissible, 3 had an exceeded limit for heavy metals, and 2 of the samples showed the presence of oxidisable substances. Out of all tested samples, only one sample met microbiological criteria for purified water. Based on the results of these analyses, it can be assumed that in many pharmacies around the country, inadequate distilled water is used which could endanger the stability of the pharmaceutical preparation and the safety of the patient. Bearing in mind that antibiotic oral suspensions are prescribed from the age of the infant, and that a large number of children consume these products for a long period due to frequent infections, the question arises as to whether prepared drugs accomplish their purpose and whether pharmacists are sufficiently aware of the importance of the quality of this type of water?","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89785886","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}
D. Maksin, M. Vukčević, Tatjana Đurkić, Ivana Stanišić, T. Bakić, Milena Radomirović, A. Onjia
Rare earth metals are deemed to be the materials of future due to their numerous applications including medical diagnostics, nuclear facilities, petroleum industry, etc. In this paper, multi-walled carbon nanotubes, which possess unique physicochemical properties, were evaluated as sorbents for lanthanoid gadolinium from aqueous solutions. The pH-dependent sorption behavior of Gd was studied in the pH range from 3 to 11 at room temperature (298 K). Equilibrium data over a range of initial Gd concentrations of 5−50 mg L−1 was analyzed with Langmuir, Freundlich and Redlich-Peterson models. Sorption kinetics was fitted with the pseudo-first-order, the pseudo-second-order and fractional power kinetic models.
{"title":"GADOLINIUM SORPTION ON MULTI-WALLED CARBON NANOTUBES","authors":"D. Maksin, M. Vukčević, Tatjana Đurkić, Ivana Stanišić, T. Bakić, Milena Radomirović, A. Onjia","doi":"10.7251/comen1901035m","DOIUrl":"https://doi.org/10.7251/comen1901035m","url":null,"abstract":"Rare earth metals are deemed to be the materials of future due to their numerous applications including medical diagnostics, nuclear facilities, petroleum industry, etc. In this paper, multi-walled carbon nanotubes, which possess unique physicochemical properties, were evaluated as sorbents for lanthanoid gadolinium from aqueous solutions. The pH-dependent sorption behavior of Gd was studied in the pH range from 3 to 11 at room temperature (298 K). Equilibrium data over a range of initial Gd concentrations of 5−50 mg L−1 was analyzed with Langmuir, Freundlich and Redlich-Peterson models. Sorption kinetics was fitted with the pseudo-first-order, the pseudo-second-order and fractional power kinetic models.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90246351","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}
Dielectric characterization of materials in the RF domain is usually carried out on samples with applied electroconductive electrodes. A high-quality contact between a sample and the measuring electrodes provides a stable current flow through the sample and information on the exact value of the electric field in which the sample is located. It also enables a simple measuring instrument to determine the dielectric parameters of the material being tested. However, the presence of contact potentials and the exchange of charge between the test material and the applied electrodes can mask some electrical phenomena in the material or significantly affect how we perceive these phenomena. In order to detect weak electrical processes in the material, for example the photoelectric response of non-polar polymers, contactless dielectric measurements must be carried out. The literature on non-contact dielectric measurements in the RF domain is poor, and because of that, this paper presents the methodology for determining the dielectric parameters of film-shaped materials in conditions of contactless dielectric measurements.
{"title":"NON-CONTACT DIELECTRIC MEASUREMENTS ON POLYMER FILMS","authors":"B. Škipina, A. S. Luyt, D. Dudić","doi":"10.7251/comen1901001s","DOIUrl":"https://doi.org/10.7251/comen1901001s","url":null,"abstract":"Dielectric characterization of materials in the RF domain is usually carried out on samples with applied electroconductive electrodes. A high-quality contact between a sample and the measuring electrodes provides a stable current flow through the sample and information on the exact value of the electric field in which the sample is located. It also enables a simple measuring instrument to determine the dielectric parameters of the material being tested. However, the presence of contact potentials and the exchange of charge between the test material and the applied electrodes can mask some electrical phenomena in the material or significantly affect how we perceive these phenomena. In order to detect weak electrical processes in the material, for example the photoelectric response of non-polar polymers, contactless dielectric measurements must be carried out. The literature on non-contact dielectric measurements in the RF domain is poor, and because of that, this paper presents the methodology for determining the dielectric parameters of film-shaped materials in conditions of contactless dielectric measurements.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80194412","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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