Search results for: x-ray absorption spectroscopy

Authors: I. Irska, S. Paszkiewicz, D. Pawlikowska, E. Piesowicz, A. Linares, T. A. Ezquerra

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Due to the number of advantages such as high tensile strength, sensitivity to hydrolytic degradation, and biocompatibility poly(lactic acid) (PLA) is one of the most common polyesters for biomedical and pharmaceutical applications. However, PLA is a rigid, brittle polymer with low heat distortion temperature and slow crystallization rate. In order to broaden the range of PLA applications, it is necessary to improve these properties. In recent years a number of new strategies have been evolved to obtain PLA-based materials with improved characteristics, including manipulation of crystallinity, plasticization, blending, and incorporation into block copolymers. Among the other methods, synthesis of aliphatic-aromatic copolyesters has been attracting considerable attention as they may combine the mechanical performance of aromatic polyesters with biodegradability known from aliphatic ones. Given the need for highly flexible biodegradable polymers, in this contribution, a series of aromatic-aliphatic based on poly(butylene terephthalate) and poly(lactic acid) (PBT-b-PLA) copolyesters exhibiting superior mechanical properties were copolymerized with an additional poly(tetramethylene oxide) (PTMO) soft block. The structure and properties of both series were characterized by means of attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR), nuclear magnetic resonance spectroscopy (¹H NMR), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and dynamic mechanical, thermal analysis (DMTA). Moreover, the related changes in tensile properties have been evaluated and discussed. Lastly, the viscoelastic properties of synthesized poly(ester-ether) copolymers were investigated in detail by step cycle tensile tests. The block lengths decreased with the advance of treatment, and the block-random diblock terpolymers of (PBT-ran-PLA)-b-PTMO were obtained. DSC and DMTA analysis confirmed unambiguously that synthesized poly(ester-ether) copolymers are microphase-separated systems. The introduction of polyether co-units resulted in a decrease in crystallinity degree and melting temperature. X-ray diffraction patterns revealed that only PBT blocks are able to crystallize. The mechanical properties of (PBT-ran-PLA)-b-PTMO copolymers are a result of a unique arrangement of immiscible hard and soft blocks, providing both strength and elasticity.

Keywords: aliphatic-aromatic copolymers, multiblock copolymers, phase behavior, thermoplastic elastomers

Procedia PDF Downloads 129

Authors: Ceren Ince, Berkay Zafer Erdem, Shahram Derogar, Nabi Yuzer

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Fibre cement plates, often used in construction, generally are made using quartz as an inert material, cement as a binder and cellulose as a fibre. This paper first of all investigates the mechanical properties and durability of fibre cement plates when quartz is both partly and fully replaced with diatomite. Diatomite does not only have lower density compared to quartz but also has high pozzolanic activity. The main objective of this paper is the investigation of the effects of supplementary cementing materials (SCMs) on the short and long term mechanical properties and durability characteristics of fibre cement plates prepared using diatomite. Supplementary cementing materials such as ground granulated blast furnace slug (GGBS) and fly ash (FA) are used in this study. 10, 20, 30 and 40% of GGBS and FA are used as partial replacement materials to cement. Short and long term mechanical properties such as compressive and flexural strengths as well as capillary absorption, sorptivity characteristics and mass were investigated. Consistency and setting time at each replacement levels of SCMs were also recorded. The effects of using supplementary cementing materials on the carbonation and sulphate resistance of fibre cement plates were then experimented. The results, first of all, show that the use of diatomite as a full or partial replacement to quartz resulted in a systematic decrease in total mass of the fibre cement plates. The reduction of mass was largely due to the lower density and finer particle size of diatomite compared to quartz. The use of diatomite did not only reduce the mass of these plates but also increased the compressive strength significantly as a result of its high pozzolanic activity. The replacement levels of both GGBS and FA resulted in a systematic decrease in short term compressive strength with increasing replacement levels. This was essentially expected as the total heat of hydration is much lower in GGBS and FA than that of cement. Long term results however, indicated that the compressive strength of fibre cement plates prepared using both GGBS and FA increases with time and hence the compressive strength of plates prepared using SCMs is either equivalent or more than the compressive strength of plates prepared using cement alone. Durability characteristics of fibre cement plates prepared using SCMs were enhanced significantly. Measurements of capillary absorption and sopritivty characteristics were also indicated that the plates prepared using SCMs has much lower permeability compared to plates prepared cement alone. Much higher resistance to carbonation and sulphate attach were observed with plates prepared using SCMs. The results presented in this paper show that the use of SCMs does not only support the production of more sustainable construction materials but also enhances the mechanical properties and durability characteristics of fibre cement plates.

Keywords: diatomite, fibre, strength, supplementary cementing material

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Authors: Djamel Djeghader, Bachir Redjel

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The composite materials of glass fibers can be used as a repair material for damage elements under repeated stresses, and in various environments. A cyclic bending characterization of a glass/polyester composite material was carried out with consideration of the period of immersion in water. These tests describe the behavior of materials and identify the mechanical fatigue characteristics using the Wohler Curve for different immersion time: 0, 90, 180 and 270 days in water. These curves are characterized by a dispersion in the lifetimes were modeled by straight whose intercepts are very similar and comparable to the static strength. This material deteriorates fatigue at a constant rate, which increases with increasing immersion time in water at a constant speed. The endurance limit seems to be independent of the immersion time in the water.

Keywords: fatigue, composite, glass, polyester, immersion, wohler

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Authors: Mahendrasingh J. Pawar, M. D. Gaoner

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Ta-doped Nb2O5 (Ta content 0.5-2% mole fraction) nanoparticles in the range of 20-40 nm were synthesized by combustion technique. The crystalline phase, morphology and size of the nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. The specific surface area of the nanoparticles was measured by nitrogen adsorption (BET analysis). The undoped Nb2O5 nanoparticles were found to have the particles size in the range of 50−80 nm. The photocatalytic performance of the samples was characterized by degrading 20 mg/L toluene under UV−Vis irradiation. The results show that the Ta-doped Nb2O5 nanoparticles exhibit a significant increase in photocatalytic performance over the undoped Nb2O5 nanoparticles, and the Nb2O5 nanoparticles doped with 1.5% Ta and calcined at 450°C show the best photocatalytic performance.

Keywords: Nb2O5, Ta-doped Nb2O5, photodegradation of Toluene, combustion method

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Authors: Vanessa Romanovicz, Beatriz A. Berns, Stephen D. Carpenter, Deyse Carpenter

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This article deals with the carbon nanotubes (CNT) synthesized from a novel precursor, sugar cane and Anodic Aluminum Oxide (AAO). The objective was to produce CNTs to be used as catalyst supports for Proton Exchange Membranes. The influence of temperature, inert gas flow rate and concentration of the precursor is presented. The CNTs prepared were characterized using TEM, XRD, Raman Spectroscopy, and the surface area determined by BET. The results show that it is possible to form CNT from sugar cane by pyrolysis and the CNTs are the type multi-walled carbon nanotubes. The MWCNTs are short and closed at the two ends with very small surface area of SBET = 3.691m,/g.

Keywords: carbon nanotubes, sugar cane, fuel cell, catalyst support

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Authors: Hanizam Awang, Mohammed Zuhear Al-Mulali

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In this study, the possibility of using unground oil palm ash (UOPA) for producing foamed concrete is investigated. The UOPA used in this study is produced by incinerating palm oil biomass at a temperature exceeding 1000ºC. A semi-structural density of 1300kg/m3 was used with filler to binder ratio of 1.5 and preliminary water to binder ratio of 0.45. Cement was replaced by UOPA at replacement levels of 0, 25, 35, 45, 55 and 65% by weight of binder. Properties such as density, compressive strength, drying shrinkage and water absorption were investigated to the age of 90 days. The mix with a 35% of UOPA content was chosen to be used as the base material of a newly designed interlocking, mortar-less block system.

Keywords: foamed concrete, oil palm ash, strength, interlocking block

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Authors: Fahad K. Alqahtani

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Nowadays construction industry is developing means to incorporate waste products in concrete to ensure sustainability. To meet the need of construction industry, a synthetic aggregate was developed using optimized technique called compression moulding press technique. The manufactured aggregate comprises mixture of plastic, waste which acts as binder, together with by-product waste which acts as fillers. The physical properties and microstructures of the inert materials and the manufactured aggregate were examined and compared with the conventional available aggregates. The outcomes suggest that the developed aggregate has potential to be used as substitution of conventional aggregate due to its less weight and water absorption. The microstructure analysis confirmed the efficiency of the manufacturing process where the final product has the same mixture of binder and filler.

Keywords: fly ash, plastic waste, quarry fine, red sand, synthetic aggregate

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Authors: Béla Kovács, Éva Bódi, Farzaneh Garousi, Szilvia Várallyay, Áron Soós, Xénia Vágó, Dávid Andrási

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In agriculture for analysis of elements in different food and food raw materials, moreover environmental samples generally flame atomic absorption spectrometers (FAAS), graphite furnace atomic absorption spectrometers (GF-AAS), inductively coupled plasma optical emission spectrometers (ICP-OES) and inductively coupled plasma mass spectrometers (ICP-MS) are routinely applied. An inductively coupled plasma mass spectrometer (ICP-MS) is capable for analysis of 70-80 elements in multielemental mode, from 1-5 cm3 volume of a sample, moreover the detection limits of elements are in µg/kg-ng/kg (ppb-ppt) concentration range. All the analytical instruments have different physical and chemical interfering effects analysing the above types of samples. The smaller the concentration of an analyte and the larger the concentration of the matrix the larger the interfering effects. Nowadays there is very important to analyse growingly smaller concentrations of elements. From the above analytical instruments generally the inductively coupled plasma mass spectrometer is capable of analysing the smallest concentration of elements. The applied ICP-MS instrument has Collision Cell Technology (CCT) also. Using CCT mode certain elements have better (smaller) detection limits with 1-3 magnitudes comparing to a normal ICP-MS analytical method. The CCT mode has better detection limits mainly for analysis of selenium, arsenic, germanium, vanadium and chromium. To elaborate an analytical method for trace elements with an inductively coupled plasma mass spectrometer the most important interfering effects (problems) were evaluated: 1) Physical interferences; 2) Spectral interferences (elemental and molecular isobaric); 3) Effect of easily ionisable elements; 4) Memory interferences. Analysing food and food raw materials, moreover environmental samples an other (new) interfering effect emerged in ICP-MS, namely the effect of various matrixes having different evaporation and nebulization effectiveness, moreover having different quantity of carbon content of food and food raw materials, moreover environmental samples. In our research work the effect of different water-soluble compounds furthermore the effect of various quantity of carbon content (as sample matrix) were examined on changes of intensity of the applied elements. So finally we could find “opportunities” to decrease or eliminate the error of the analyses of applied elements (Cr, Co, Ni, Cu, Zn, Ge, As, Se, Mo, Cd, Sn, Sb, Te, Hg, Pb, Bi). To analyse these elements in the above samples, the most appropriate inductively coupled plasma mass spectrometer is a quadrupole instrument applying a collision cell technique (CCT). The extent of interfering effect of carbon content depends on the type of compounds. The carbon content significantly affects the measured concentration (intensities) of the above elements, which can be corrected using different internal standards.

Keywords: elements, environmental and food samples, ICP-MS, interference effects

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Authors: Azeez Shaik, Yagnik Kalariya, Amit Salvi

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High-performance requirements and emission norms were forcing the automobile industry to opt for lightweight materials which improve the fuel efficiency and absorb energy during crash applications. In such scenario, the woven fabric composites are providing better energy absorption compared to metals. Woven fabric composites have a repetitive unit cell (RUC) and the mechanical properties of these materials are highly dependent on RUC. This work investigates the importance of detailed modelling of the RUC, the size effects associated and the mitigation techniques to avoid them using Finite element analysis approach.

Keywords: repetitive unit cell, representative volume element, size effects, cohesive zone, finite element analysis

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Authors: Megan Burfoot, Ali GhaffarianHoseini, Nicola Naismith, Amirhosein GhaffarianHoseini

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Intelligent Acoustic Technology (IAT) is a novel architectural device used in buildings to automatically vary the acoustic conditions of space. IAT is realized by integrating two components: Variable Acoustic Technology (VAT) and an intelligent system. The VAT passively alters the RT by changing the total sound absorption in a room. In doing so, the Reverberation Time (RT) is changed and thus, the sound strength and clarity are altered. The intelligent system detects sound waves in real-time to identify the aural situation, and the RT is adjusted accordingly based on pre-programmed algorithms. IAT - the synthesis of these two components - can dramatically improve acoustic comfort, as the acoustic condition is automatically optimized for any detected aural situation. This paper presents an evaluation of the improvements of acoustic comfort in an existing tertiary classroom located at Auckland University of Technology in New Zealand. This is a pilot case study, the first of its’ kind attempting to quantify the benefits of IAT. Naturally, the potential acoustic improvements from IAT can be actualized by only installing the VAT component of IAT and by manually adjusting it rather than utilizing an intelligent system. Such a simplified methodology is adopted for this case study to understand the potential significance of IAT without adopting a time and cost-intensive strategy. For this study, the VAT is built by overlaying reflective, rotating louvers over sound absorption panels. RT's are measured according to international standards before and after installing VAT in the classroom. The louvers are manually rotated in increments by the experimenter and further RT measurements are recorded. The results are compared with recommended guidelines and reference values from national standards for spaces intended for speech and communication. The results obtained from the measurements are used to quantify the potential improvements in classroom acoustic comfort, where IAT to be used. This evaluation reveals the current existence of poor acoustic conditions in the classroom caused by high RT's. The poor acoustics are also largely attributed to the classrooms’ inability to vary acoustic parameters for changing aural situations. The classroom experiences one static acoustic state, neglecting to recognize the nature of classrooms as flexible, dynamic spaces. Evidently, when using VAT the classroom is prescribed with a wide range of RTs it can achieve. Namely, acoustic requirements for varying teaching approaches are satisfied, and acoustic comfort is improved. By quantifying the benefits of using VAT, it can confidently suggest these same benefits are achieved with IAT. Nevertheless, it is encouraged that future studies continue this line of research toward the eventual development of IAT and its’ acceptance into mainstream architecture.

Keywords: acoustic comfort, classroom acoustics, intelligent acoustics, variable acoustics

Procedia PDF Downloads 175

Authors: A. G. Pershina, P. S. Postnikov, M. E. Trusova, D. O. Burlakova, A. E. Sazonov

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Invention of magnetic-fluorescent nanocomposites is a rapidly developing area of research. The magnetic-fluorescent nanocomposite attractiveness is connected with the ability of simultaneous management and control of such nanocomposites by two independent methods based on different physical principles. These nanocomposites are applied for the solution of various essential scientific and experimental biomedical problems. The aim of this research is development of principle approach to nanobiohybrid structures with magnetic and fluorescent properties design. The surface of carbon-coated iron nanoparticles (Fe@C) were covalently modified by 4-carboxy benzenediazonium tosylate. Recombinant fluorescent protein TagGFP2 (Eurogen) was obtained in E. coli (Rosetta DE3) by standard laboratory techniques. Immobilization of TagGFP2 on the nanoparticles surface was provided by the carbodiimide activation. The amount of COOH-groups on the nanoparticle surface was estimated by elemental analysis (Elementar Vario Macro) and TGA-analysis (SDT Q600, TA Instruments. Obtained nanocomposites were analyzed by FTIR spectroscopy (Nicolet Thermo 5700) and fluorescence microscopy (AxioImager M1, Carl Zeiss). Amount of the protein immobilized on the modified nanoparticle surface was determined by fluorimetry (Cary Eclipse) and spectrophotometry (Unico 2800) with the help of preliminary obtained calibration plots. In the FTIR spectra of modified nanoparticles the adsorption band of –COOH group around 1700 cm-1 and bands in the region of 450-850 cm-1 caused by bending vibrations of benzene ring were observed. The calculated quantity of active groups on the surface was equal to 0,1 mmol/g of material. The carbodiimide activation of COOH-groups on nanoparticles surface results to covalent immobilization of TagGFP2 fluorescent protein (0.2 nmol/mg). The success of immobilization was proved by FTIR spectroscopy. Protein characteristic adsorption bands in the region of 1500-1600 cm-1 (amide I) were presented in the FTIR spectrum of nanocomposite. The fluorescence microscopy analysis shows that Fe@C-TagGFP2 nanocomposite possesses fluorescence properties. This fact confirms that TagGFP2 protein retains its conformation due to immobilization on nanoparticles surface. Magnetic-fluorescent nanocomposite was obtained as a result of unique design solution implementation – the fluorescent protein molecules were fixed to the surface of superparamagnetic carbon-coated iron nanoparticles using original diazonium salts.

Keywords: carbon-coated iron nanoparticles, diazonium salts, fluorescent protein, immobilization

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Authors: Rajeev Jain, Nimisha Jadon, Kshiti Singh

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Titanium oxide nanoparticles and 1-butyl-2,3-dimethylimidazolium bis (trifluoromethane- sulfonyl) imide modified glassy carbon electrode (TiO2/IL/GCE) has been fabricated for electrochemical sensing of flunarizine dihydrochloride (FRH). The electrochemical properties and morphology of the prepared nanocomposite were studied by electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM). The response of the electrochemical sensor was found to be proportional to the concentrations of FRH in the range from 0.5 µg mL-1 to 16 µg mL-1. The detection limit obtained was 0.03 µg mL-1. The proposed method was also applied to the determination of FRH in pharmaceutical formulation and human serum with good recoveries.

Keywords: flunarizine dihydrochloride, ionic liquid, nanoparticles, voltammetry, human serum

Procedia PDF Downloads 308

Authors: Irshad U. Khan, Tanmay Paul, Murali Mohan Seepana

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This paper presents a study on synthesizing and characterizing a Copper oxide doped Carbon (CuO-C) electrocatalyst for the negative half-cell reactions of Vanadium Redox Flow Battery (VRFB). The CuO was synthesized using a microreactor. The electrocatalyst was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (SEM). The electrochemical performance was assessed by linear sweep voltammetry (LSV). The findings suggest that the synthesized CuO exhibited favorable crystallinity, morphology, and surface area, which reflects improved cell performance.

Keywords: ECSA, electrocatalyst, energy storage, Tafel

Procedia PDF Downloads 69

Authors: Amiza Surmi, Azmi Shariff, Sow Mun Serene Lock

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In recent decades, there has been a significant emphasis on the pivotal role of Rotating Packed Beds (RPBs) in absorption processes, encompassing the removal of Volatile Organic Compounds (VOCs) from groundwater, deaeration, CO2 absorption, desulfurization, and similar critical applications. The primary focus is elevating mass transfer rates, enhancing separation efficiency, curbing power consumption, and mitigating pressure drops. Additionally, substantial efforts have been invested in exploring the adaptation of RPB technology for offshore deployment. This comprehensive study delves into the intricacies of nitrogen removal under low temperature and high-pressure conditions, employing the high gravity principle via innovative RPB distillation concept with a specific emphasis on optimizing mass transfer. Based on the author's knowledge and comprehensive research, no cryogenic experimental testing was conducted to remove nitrogen via RPB. The research identifies pivotal process control factors through meticulous experimental testing, with pressure, reflux ratio, and reboil ratio emerging as critical determinants in achieving the desired separation performance. The results are remarkable, with nitrogen removal reaching less than one mole% in the Liquefied Natural Gas (LNG) product and less than three moles% methane in the nitrogen-rich gas stream. The study further unveils the mass transfer coefficient, revealing a noteworthy trend of decreasing Number of Transfer Units (NTU) and Area of Transfer Units (ATU) as the rotational speed escalates. Notably, the condenser and reboiler impose varying demands based on the operating pressure, with lower pressures at 12 bar requiring a more substantial duty than the 15-bar operation of the RPB. In pursuit of optimal energy efficiency, a meticulous sensitivity analysis is conducted, pinpointing the ideal combination of pressure and rotating speed that minimizes overall energy consumption. These findings underscore the efficiency of the RPB distillation approach in effecting efficient separation, even when operating under the challenging conditions of low temperature and high pressure. This achievement is attributed to a rigorous process control framework that diligently manages the operational pressure and temperature profile of the RPB. Nonetheless, the study's conclusions point towards the need for further research to address potential scaling challenges and associated risks, paving the way for the industrial implementation of this transformative technology.

Keywords: mass transfer coefficient, nitrogen removal, liquefaction, rotating packed bed

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Authors: Xin Chang, Daping Chu

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Oxygen gas sensing technology has progressed since the last century and it has been extensively used in a wide range of applications such as controlling the combustion process by sensing the oxygen level in the exhaust gas of automobiles to ensure the catalytic converter is in a good working condition. Similar sensors are also used in industrial boilers to make the combustion process economic and environmentally friendly. Different gas sensing mechanisms have been developed: ceramic-based potentiometric equilibrium sensors and semiconductor-based sensors by oxygen absorption. In this work, we present a highly sensitive and low-cost oxygen gas sensor based on Zinc Oxide nanoparticles (average particle size of 35nm) dispersion in ethanol. The sensor is able to measure the pressure range from 103 mBar to 10-5 mBar with a sensitivity of more than 102 mA/Bar. The sensor is also erasable with heat.

Keywords: nanoparticles, oxygen, sensor, ZnO

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Authors: Debdut Roy, Vidyasagar Guggilla

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In this research, we highlight our exploratory work on modified zeolite based catalysts for catalytic cracking of hydrocarbons for production of light olefin i.e. ethylene and propylene. The work is focused on understanding the catalyst structure and activity correlation. Catalysts are characterized by surface area and pore size distribution analysis, inductively coupled plasma optical emission spectrometry (ICP-OES), Temperature Programmed Desorption (TPD) of ammonia, pyridine Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermo-gravimetric Analysis (TGA) and correlated with the catalytic activity. It is observed that the yield of lighter olefins increases with increase of Bronsted acid strength.

Keywords: catalytic cracking, zeolite, propylene, structure-activity correlation

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Authors: Thanh Phuong Doan, Narueporn Sutanthavibul

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The influence of freezing cycle on influenza haemagglutinin (HA) conformational stability was investigated in terms of freezing rates and formulation compositions. The results showed that appropriate HA conformation could be evaluated using circular dichroism (CD) spectroscopy with HA concentration of greater than 0.09 mg/ml. The intermediate freezing rate of approximately 1.0oC/min preserved the original HA conformation better than at slow freezing rate (0.5oC/min) and rapid freezing rate (2.6oC/min). The changes in CD spectra of the secondary HA structure were more pronounced than those of the tertiary HA structure during the evaluation. Additionally, the formulations, which resulted in the highest conformational stability were found to have sucrose present in the composition. As opposed to when only glycine was used, the stability of HA conformation was poor.

Keywords: freezing, haemagglutinin, influenza, circular dichroism

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Authors: Viney Dixit, Rohit R. Shahi, Ashish Bhatnagar, P. Jain, T. P. Yadav, O. N. Srivastava

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Carbons are being widely investigated as hydrogen storage material owing to their light weight, fast hydrogen absorption kinetics and low cost. However, these materials suffer from low hydrogen storage capacity at room temperature. The aim of the present study is to synthesize carbon based material which shows moderate hydrogen storage at room temperature. For this purpose, hydrogenation characteristics of natural precursor coconut kernel is studied in this work. The hydrogen storage measurement reveals that the as-synthesized materials have good hydrogen adsorption and desorption capacity with fast kinetics. The synthesized material absorbs 8 wt.% of hydrogen at liquid nitrogen temperature and 2.3 wt.% at room temperature. This could be due to the presence of certain elements (KCl, Mg, Ca) which are confirmed by TEM.

Keywords: coconut kernel, carbonization, hydrogenation, KCl, Mg, Ca

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Authors: S. Vasailor, C. Rattanakawin

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Electro-winning of copper metal from dilute sulfate solution (13.7 g/L) was performed in a lab electrolytic cell with stainless-steel cathode and lead-alloy anode. The effects of various parameters including cell voltage, electro-winning temperature and time were studied in order to acquire an appropriate current efficiency of copper deposition. The highest efficiency is about 95% obtaining from electro-winning condition of 3V, 55°C and 3,600 s correspondingly. The cathode copper with 95.5% Cu analyzed using atomic absorption spectrometry can be obtained from this single-winning condition. In order to increase the copper grade, solvent extraction should be used to increase the sulfate concentration, say 50 g/L, prior to winning the cathode copper effectively.

Keywords: copper metal, current efficiency, dilute sulfate solution, electro-winning

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Authors: Homayon Ahmad Panahi, Seyed Mehdi Seyed Nejad, Elham Moniri

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A novel bio-adsorbent is fabricated by attaching a cibacron blue to yeast cells. The modified bio-sorbent has been characterized by some techniques like Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (CHN) and applied for the preconcentration and determination of samarium from aqueous water samples. The best pH value for adsorption of the brilliant crecyle blue by yeast cells- cibacron blue was 7. The sorption capacity of modified biosorbent was 18.5 mg. g⁻¹. A recovery of 95.3% was obtained for Sm(III) when eluted with 0.5 M nitric acid. The method was applied for Sm(III) preconcentration and determination in river water sample.

Keywords: samarium, solid phase extraction, yeast cells, water sample, removal

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Authors: Haba Hamada, Lavaud Cathrine, Benkhaled Mohammed

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The Silene genus is the most representative of the caryophyllaceae family for their rich content in secondary metabolites; saponins, flavonoids and flavonoids glycosides, phytoecdysones, oligosaccharides have been isolated and identified. The Silene genus represented by about 700 species in the temrerate region of the word, the main concentration of spcies is Europe, Asia and North Africa. Three known compounds 1-3 were isolated from the aerial parts of Silene arenarioides Desf. by using different chromatographic methods. The structures of the isolated compounds were determined as stigmasterolglycoside, Soyacerebroside, maltol glycoside. The structures of the isolated compounds were determined by using the NMR (1H-NMR, 13C-NMR, COSY, HSQC, and HMBC) techniques and mass spectroscopy. The antimicrobial and antioxydant activities of the different extracts and compound have been reported.

Keywords: caryophyllaceae, flavonoids, saponosids, flavonoids glycosides

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Authors: Merve Küçük, M. Lütfi Öveçoğlu

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Zinc oxide particles were synthesized using the sol-gel method and dip coated on polyester fabric. X-ray diffraction (XRD) analysis revealed a single crystal phase of ZnO particles. Chemical characteristics of the polyester fabric surface were investigated using attenuated total reflection-Fourier transform infrared (ATR-FTIR) measurements. Morphology of ZnO coated fabric was analyzed using field emission scanning electron microscopy (FESEM). After particle analysis, the aqueous ZnO solution resulted in a narrow size distribution at submicron levels. The deposit of ZnO on polyester fabrics yielded a homogeneous spread of spherical particles. Energy dispersive X-ray spectroscopy (EDX) results also affirmed the presence of ZnO particles on the polyester fabrics.

Keywords: dip coating, polyester fabrics, sol gel, zinc oxide

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Authors: A. A. Azemati, H. Hosseini

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By using an adequate paint in buildings, energy consumption can be decreased. In this research, a range of wall paints in different climatic conditions has been investigated to observe its effect on energy consumption. In the current study, the researchers have investigated the effect of different parameters including climatic condition, absorption coefficient, and thermal loads on paint coating. In order to study these effects, heating and cooling loads of a typical building with different color paints have been calculated. The effect of building paint in different climatic condition was studied and a comparison was drawn between paints and painting coats with inorganic micro particles in temperate climate to obtain optimized energy consumption.

Keywords: climate, energy consumption, inorganic, painting coats

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Authors: D. Berdous, H. Ferfera-Harrar

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Superabsorbent polymers (SAPs) or hydrogels with three-dimensional hydrophilic network structure are high-performance water absorbent and retention materials. The in situ synthesis of metal nanoparticles within polymeric network as antibacterial agents for bio-applications is an approach that takes advantage of the existing free-space into networks, which not only acts as a template for nucleation of nanoparticles, but also provides long term stability and reduces their toxicity by delaying their oxidation and release. In this work, SAP/nanosilver nanocomposites were successfully developed by a unique green process at room temperature, which involves in situ formation of silver nanoparticles (AgNPs) within hydrogels as a template. The aim of this study is to investigate whether these AgNPs-loaded hydrogels are potential candidates for antimicrobial applications. Firstly, the superabsorbents were prepared through radical copolymerization via grafting and crosslinking of acrylamide (AAm) onto chitosan backbone (Cs) using potassium persulfate as initiator and N,N’-methylenebisacrylamide as the crosslinker. Then, they were hydrolyzed to achieve superabsorbents with ampholytic properties and uppermost swelling capacity. Lastly, the AgNPs were biosynthesized and entrapped into hydrogels through a simple, eco-friendly and cost-effective method using aqueous silver nitrate as a silver precursor and curcuma longa tuber-powder extracts as both reducing and stabilizing agent. The formed superabsorbents nanocomposites (Cs-g-PAAm)/AgNPs were characterized by X-ray Diffraction (XRD), UV-visible Spectroscopy, Attenuated Total reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Inductively Coupled Plasma (ICP), and Thermogravimetric Analysis (TGA). Microscopic surface structure analyzed by Transmission Electron Microscopy (TEM) has showed spherical shapes of AgNPs with size in the range of 3-15 nm. The extent of nanosilver loading was decreased by increasing Cs content into network. The silver-loaded hydrogel was thermally more stable than the unloaded dry hydrogel counterpart. The swelling equilibrium degree (Q) and centrifuge retention capacity (CRC) in deionized water were affected by both contents of Cs and the entrapped AgNPs. The nanosilver-embedded hydrogels exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. These comprehensive results suggest that the elaborated AgNPs-loaded nanomaterials could be used to produce valuable wound dressing.

Keywords: antibacterial activity, nanocomposites, silver nanoparticles, superabsorbent Hydrogel

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Authors: Antonina A. Shumakova, Sergey A. Khotimchenko

Abstract:

The relevance of research is associated, on the one hand, with an ever-increasing volume of production and the expansion of the scope of application of engineered nanomaterials (ENMs), and on the other hand, with the lack of sufficient scientific information on the nature of the interactions of nanoparticles (NPs) with components of biogenic and abiogenic origin. In particular, studying the effect of ENMs (TiO2 NPs, SiO2 NPs, Al2O3 NPs, fullerenol) on the toxicometric characteristics of common contaminants such as lead and cadmium is an important hygienic task, given the high probability of their joint presence in food products. Data were obtained characterizing a multidirectional change in the toxicity of model toxicants when they are co-administered with various types of ENMs. One explanation for this fact is the difference in the adsorption capacity of ENMs, which was further studied in in vitro studies. For this, a method was proposed based on in vitro modeling of conditions simulating the environment of the small intestine. It should be noted that the obtained data are in good agreement with the results of in vivo experiments: - with the combined administration of lead and TiO2 NPs, there were no significant changes in the accumulation of lead in rat liver; in other organs (kidneys, spleen, testes and brain), the lead content was lower than in animals of the control group; - studying the combined effect of lead and Al2O3 NPs, a multiple and significant increase in the accumulation of lead in rat liver was observed with an increase in the dose of Al2O3 NPs. For other organs, the introduction of various doses of Al2O3 NPs did not significantly affect the bioaccumulation of lead; - with the combined administration of lead and SiO2 NPs in different doses, there was no increase in lead accumulation in all studied organs. Based on the data obtained, it can be assumed that at least three scenarios of the combined effects of ENMs and chemical contaminants on the body: - ENMs quite firmly bind contaminants in the gastrointestinal tract and such a complex becomes inaccessible (or inaccessible) for absorption; in this case, it can be expected that the toxicity of both ENMs and contaminants will decrease; - the complex formed in the gastrointestinal tract has partial solubility and can penetrate biological membranes and / or physiological barriers of the body; in this case, ENMs can play the role of a kind of conductor for contaminants and, thus, their penetration into the internal environment of the body increases, thereby increasing the toxicity of contaminants; - ENMs and contaminants do not interact with each other in any way, therefore the toxicity of each of them is determined only by its quantity and does not depend on the quantity of another component. Authors hypothesized that the degree of adsorption of various elements on the surface of ENMs may be a unique characteristic of their action, allowing a more accurate understanding of the processes occurring in a living organism.

Keywords: absorption, cadmium, engineered nanomaterials, lead

Procedia PDF Downloads 77

Authors: F. Fernandes, C. Poleto

Abstract:

This paper aims at assessing the concentrations of heavy metals and the isotopic composition of lead ²¹⁰Pb in different fractions of sediment produced in the watershed that makes up the Mãe d'água dam and thus characterizing the distribution of metals along the sedimentary column and inferencing in the urbanization of the same process. Sample collection was carried out in June 2014; eight sediment cores were sampled in the lake of the dam. For extraction of the sediments core, a core sampler “Piston Core” was used. The trace metal concentrations were determined by conventional atomic absorption spectrophotometric methods. The samples were subjected to radiochemical analysis of ²¹⁰Po. ²¹⁰Pb activity was obtained by measuring ²¹⁰Po activity. The chronology was calculated using the constant rate of supply (CRS). ²¹⁰Pb is used to estimate the sedimentation rate.

Keywords: ²¹⁰Pb dating method, heavy metal, lakes urban, pollution history

Procedia PDF Downloads 288

Authors: Abdurahim Abogdera, Omar Hamza, David Elliott

Abstract:

The soil bacteria can be affected by some factors such as pH, calcium ions and Electrical conductivity. Fresh concrete has high pH value, which is between 11 and 13 and these values will be prevented the bacteria to produce CO₂ to participate with Calcium ions that released from the concrete to get calcite. In this study we replaced 15% and 25% of cement with Fly ash as the fly ash reduce the value of the pH at the concrete. The main goal of this study was investigated whether bacteria can be used on the soil rather than in the concrete to avoid the challenges and limitations of containing bacteria inside the concrete. This was achieved by incubating cracked cement mortar specimens into fully saturated sterilized and non-sterilized soil. The crack sealing developed in the specimens during the incubation period in both soil conditions were evaluated and compared. Visual inspection, water absorption test, scanning electron microscopy (SEM), and Energy Dispersive X-ray (EDX) were conducted to evaluate the healing process.

Keywords: pH, calcium ions, MICP, salinity

Procedia PDF Downloads 101

Authors: C. Rattanakawin, S. Vasailor

Abstract:

Acid leaching of flotation concentrate of oxide copper ore containing mainly of malachite was performed in a standard agitation tank with various parameters. The effects of solid to liquid ratio, sulfuric acid concentration, agitation speed, leaching temperature and time were examined to get proper conditions. The best conditions are 1:8 solid to liquid ratio, 10% concentration by weight, 250 rev/min, 30 ^oC and 5-min leaching time in respect. About 20% Cu grade assayed by atomic absorption technique with 98% copper recovery was obtained from these combined optimum conditions. Dissolution kinetics of the concentrate was approximated as a logarithmic function. As a result, the first-order reaction rate is suggested from this leaching study.

Keywords: agitation leaching, dissolution kinetics, flotation concentrate, oxide copper ore, sulfuric acid

Procedia PDF Downloads 106

Authors: Anika Zafiah M. Rus, Nur Munirah Abdullah, M. F. L. Abdullah

Abstract:

The fabrication and characterization of composite films of graphite- bioepoxy is described. Free-standing thin films of ~0.1 mm thick are prepared using a simple solution mixing with mass proportion of 7/3 (bioepoxy/graphite) and drop casting at room temperature. Fourier transform infra-red spectroscopy (FTIR) and Ultraviolet-visible (UV-vis) spectrophotometer are performed to evaluate the changes in chemical structure and adsorption spectra arising with the increasing of graphite weight loading (wt.%) into the biopolymer matrix. The morphologic study shows a homogeneously dispersed and strong particle bonding between the graphite and the bioepoxy, with conductivity of the film 103 S/m, confirming the efficiency of the processes.

Keywords: absorbance peak, biopolymer, graphite- bioepoxy composites, particle bonding

Procedia PDF Downloads 497

Authors: D. ChobfroushKhoei, S. K. Heidari , Sh. Dariadel

Abstract:

Carbon nanotubes were used in medical sciences especially in drug delivery system and cancer therapy. In this study, we functionalized carboxylated single-wall carbon nanotubes (SWNT-COOH) with 2-en 4-hydroxy cyclo 1-octanon. Synthesized sample was characterized by FT-IR, Raman spectroscopy, SEM, TGA and cellular investigations. The results showed well formation of SWNT-Ester. Cell viability assay results and microscopic observations demonstrated that cancerous cells were killed in the sample. The synthesized sample can be used as a toxic material for cancer therapy.

Keywords: MWNT-COOH, functionalization, phenylisocyanate, phenylisothiocyanate, 1, 4-phenylendiamine, toxicity investigation

Procedia PDF Downloads 435