Search results for: vapor absorption

Authors: M. Shirinbayan, J. Fitoussi, N. Abbasnezhad, A. Lucas, A. Tcharkhtchi

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Sheet Molding Compounds (SMCs) with special microstructures are very attractive to use in automobile structures especially when they are accidentally subjected to collision type accidents because of their high energy absorption capacity. These are materials designated as standard SMC, Advanced Sheet Molding Compounds (A-SMC), Low-Density SMC (LD-SMC) and etc. In this study, testing methods have been performed to compare the mechanical responses and damage phenomena of SMC, LD-SMC, and A-SMC under quasi-static and high strain rate tensile tests. The paper also aims at investigating the effect of an initial pre-damage induced by fatigue on the tensile dynamic behavior of A-SMC. In the case of SMCs and A-SMCs, whatever the fibers orientation and applied strain rate are, the first observed phenomenon of damage corresponds to decohesion of the fiber-matrix interface which is followed by coalescence and multiplication of these micro-cracks and their propagations. For LD-SMCs, damage mechanisms depend on the presence of Hollow Glass Microspheres (HGM) and fibers orientation.

Keywords: SMC, Sheet Molding Compound, LD-SMC, Low-Density SMC, A-SMC, Advanced Sheet Molding Compounds, HGM, Hollow Glass Microspheres, damage

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Authors: Madhuresh Dwivedi, Navneet Singh Deora, Aastha Deswal, H. N. Mishra

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FT-NIR spectroscopy and electronic nose was used to study the kinetics of dough proofing. Spectroscopy was conducted with an optic probe in the diffuse reflectance mode. The dough leavening was carried out at different temperatures (25 and 35°C) and constant RH (80%). Spectra were collected in the range of wave numbers from 12,000 to 4,000 cm-1 directly on the samples, every 5 min during proofing, up to 2 hours. NIR spectra were corrected for scatter effect and second order derivatization was done to transform the spectra. Principal component analysis (PCA) was applied for the leavening process and process kinetics was calculated. PCA was performed on data set and loadings were calculated. For leavening, four absorption zones (8,950-8,850, 7,200-6,800, 5,250-5,150 and 4,700-4,250 cm-1) were involved in describing the process. Simultaneously electronic nose was also used for understanding the development of odour compounds during fermentation. The electronic nose was able to differential the sample on the basis of aroma generation at different time during fermentation. In order to rapidly differentiate samples based on odor, a Principal component analysis is performed and successfully demonstrated in this study. The result suggests that electronic nose and FT-NIR spectroscopy can be utilized for the online quality control of the fermentation process during leavening of bread dough.

Keywords: FT-NIR, dough, e-nose, proofing, principal component analysis

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Authors: Stephen Akong Takim

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This study focused on the optimization of the flexural strength of bio-composite samples of palm kernel, whelks, clams, periwinkles shells and bamboo fiber reinforced with resin for engineering applications. The aim of the study was to formulate different samples of bio-composite reinforced with resin for engineering applications and to evaluate the flexural strength of the fabricated composite. The hand lay-up technique was used for the composites produced by incorporating different percentage compositions of the shells/fiber (10%, 15%, 20%, 25% and 30%) into varied proportions of epoxy resin and catalyst. The cured samples, after 24 hours, were subjected to tensile, impact, flexural and water absorption tests. The experiments were conducted using the Taguchi optimization method L25 (5x5) with five design parameters and five level combinations in Minitab 18 statistical software. The results showed that the average value of flexural was 114.87MPa when compared to the unreinforced 72.33MPa bio-composite. The study recommended that agricultural waste, like palm kernel shells, whelk shells, clams, periwinkle shells and bamboo fiber, should be converted into important engineering applications.

Keywords: bio-composite, resin, palm kernel shells, welk shells, periwinkle shells, bamboo fiber, Taguchi techniques and engineering application

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Authors: Jiwan P. Lavande, A. V. Chandewar

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In the present study, orodispersible tablets of diphenhydramine hydrochloride were prepared using croscarmellose sodium, crospovidone and camphor, menthol (as subliming agents) in different ratios and ODTs prepared with superdisintegrants were compared with ODTs prepared with camphor and menthol (subliming agents) for the following evaluation of in vitro disintegration time, dispersion time, wetting time, hardness and water absorption ratio. Results revealed that the tablets of all formulations have acceptable physical parameters. The drug and excipients compatibility study was evaluated using FTIR technique and has not detected any incompatibility. The in vitro release of drug from DC6 formulation was quick when compared to other formulations. Stability study was carried out as per ICH guidelines for three months and results revealed that upon storage disintegration time of tablets had not shown any significant difference. Microscopic study of different formulations of sublimed tablets showed formation of pores for the tablets prepared by sublimation method. Thus, conclusion can be made that the stable orodispersible tablets of diphenhydramine hydrochloride can be developed for the rapid release of diphenhydramine hydrochloride.

Keywords: orodispersible tablet, subliming agent, super disintegrants, diphenhydramine hydrochloride

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Authors: S. Krustev, V. Angelova, K. Ivanov, P. Zaprjanova

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Approximately a dozen trace elements are vital for the development of all plants and some other elements are significant for some species. Heavy metals do not belong to this group of elements that are essential to plants, but some of them such as copper and zinc, have a dual effect on their growth. Concentration levels of these elements in the different regions of the world vary considerably. Their high concentrations in some parts of Central and Eastern Europe cause concern for human health and degrade the quality of agricultural produce from these areas. This study aims to compare the prevalence and levels of the major trace elements in some rural areas of Central and Eastern Europe. Soil samples from different regions of the Czech Republic, Slovakia, Austria, Hungary, Serbia, Romania, Bulgaria and Greece far from large industrial centers have been studied. The main methods for their determination are the atomic spectral techniques – atomic absorption and plasma atomic emission. As a result of this study, data on microelements levels in soils of 17 points from the main grain-producing regions of Central and Eastern Europe are presented and systematized. The content of trace elements was in the range of 5.0-84.1 mg.kg⁻¹ for Cu, 0.3-1.4 mg.kg⁻¹ for Cd, 26.1-225.5 mg.kg⁻¹ for Zn, 235.5-788.6 mg.kg⁻¹ for Mn and 4.1-25.8 mg.kg⁻¹ for Pb.

Keywords: trace elements, heavy metals, agricultural soils, Central and Eastern Europe

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Authors: Kianoosh Samimi, Farhad Estakhr, Mahdi Mahdikhani, Faramaz Moodi

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The self-consolidating concrete (SCC) performance over ordinary concrete is generally related to the ingredients used. The metakaolin can modify various properties of concrete, due to high pozzolanic reactions and also makes a denser microstructure. The objective of this paper is to examine the influence of three types of Portland cement and metakaolin on compressive strength and transport properties of SCC at early ages and up to 90 days. Six concrete mixtures were prepared with three types of different cements and substitution of 15% metakaolin. The results show that the highest value of compressive strength was achieved for Portland Slag Cement (PSC) and without any metakaolin at age of 90 days. Conversely, the lowest level of compressive strength at all ages of conservation was obtained for Pozzolanic Portland Cement (PPC) and containing 15% metakaolin. As can be seen in the results, compressive strength in SCC containing Portland cement type II with metakaolin is higher compared to that relative to SCC without metakaolin from 28 days of age. On the other hand, the samples containing PSC and PPC with metakaolin had a lower compressive strength than the plain samples. Therefore, it can be concluded that metakaolin has a negative effect on the compressive strength of SCC containing PSC and PPC. In addition, results show that metakaolin has enhanced chloride durability of SCCs and reduced capillary water absorption at 28, 90 days.

Keywords: SCC, metakaolin, cement type, compressive strength, chloride diffusion

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Authors: M. A. Lawal, A. Uzairu, M. S. Sallau

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The presence and bioaccumulation of lead (Pb), cadmium (Cd), and chromium (Cr) in blood, urine, nail, and hair samples of electronic repair technicians in Kaduna-Nigeria were assessed using Fast Sequential Atomic Absorption Spectrophotometry. 10 electronic repair technicians from within Kaduna Metropolis volunteered for the pilot study. The mean blood concentrations of Pb, Cd, and Cr in the subjects were 29.33 ± 4.80, 7.78 ± 10.57, and 24.78 ± 21.77 µg/dL, respectively. The mean urine concentrations of Pb, Cd, and Cr were 24.18 ± 2.98, 6.81 ± 10.05, and 14.78 ± 14.20 µg/dL, respectively. Mean nail metal values of 37.13 ± 4.08, 1.00 ± 1.21, and 18.49 ± 12.71 µg/g were obtained for Pb, Cd, and Cr, respectively while mean hair metal values of 39.41 ± 5.63, 1.09 ± 1.14, and 19.13 ± 11.61 µg/g for Pb, Cd, and Cr, respectively. Positive Pearson correlation coefficients were observed between Pb/Cd, Pb/Cr, and Cd/Cr in all samples and they indicate the metals are likely from the same pollution source. The mean concentrations of the metals in all samples were higher than the WHO, ILO, and ACGIH standards, implying the repairers are likely occupationally exposed and are subject to serious health concerns. Social habits like smoking were found to significantly affect the concentrations of these metals. The level of education, use of safety devices, period of exposure, the nature of electronics and the age of the repairers were also found to remarkably affect the concentrations of the metals.

Keywords: bioaccumulation, electronic repair technicians, heavy metals, occupational hazard

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Authors: Behzad Panahirad, UğUr Atikol

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The current study is based on a combined heat and power system with multi-objectives, driven by biomass. The system consists of a combustion chamber (CC), a single effect absorption cooling system (SEACS), an air conditioning unit (AC), a reheat steam Rankine cycle (RRC), an organic Rankine cycle (ORC) and an electrolyzer. The purpose of this system is to produce hydrogen, electricity, heat, cooling, and air conditioning. All the simulations had been performed by Engineering Equation Solver (EES) software. Pine sawdust is the selected biofuel for the combustion process. The overall utilization factor (εₑₙ) and exergetic efficiency (ψₑₓ) were calculated to be 2.096 and 24.03% respectively. The performed renewable and environmental impact analysis indicated a sustainability index of 1.316 (SI) and a specific CO2 emission of 353.8 kg/MWh. The parametric study is conducted based on the variation of ambient (sink) temperature, biofuel mass flow rate, and boilers outlet temperatures. The parametric simulation showed that the increase in biofuel mass flow rate has a positive effect on the sustainability of the system.

Keywords: biomass, exergy assessment, multi-objective plant, CO₂ emission, irreversibility

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Authors: Gizachew Belay Adugna

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Perovskite solar cells (PSCs) shows rapid development as an emerging photovoltaic material; however, the fast device degradation due to the organic nature, mainly hole transporting material (HTM) and lack of robust and reliable upscaling process for photovoltaic module hindered its commercialization. Herein, HTM molecules with/without fluorine-substituted cyclopenta[2,1-b;3,4-b’]dithiophene derivatives (HYC-oF, HYC-mF, and HYC-H) were developed for PSCs application. The fluorinated HTM molecules exhibited better hole mobility and overall charge extraction in the devices mainly due to strong molecular interaction and packing in the film. Thus, the highest power conversion efficiency (PCE) of 19.64% with improved long stability was achieved for PSCs based on HYC-oF HTM. Moreover, the fluorinated HYC-oF demonstrated excellent film processability in a larger-area substrate (10 cm×10 cm) prepared sequentially with the absorption perovskite underlayer via a scalable bar coating process in ambient air and owned a higher PCE of 18.49% compared to the conventional spiro-OMeTAD (17.51%). The result demonstrates a facile development of HTM towards stable and efficient PSCs for future industrial-scale PV modules.

Keywords: perovskite solar cells, upscaling film coating, power conversion efficiency, solution processing

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Authors: Samera Salimpour Abkenar

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In traditional dyeing of natural fibers with natural dyes, metal salts are commonly used to increase color stability. This method always carries the risk of environmental pollution (contamination of arable soils and fresh groundwater) due to the release of dyeing effluents containing large amounts of metal. Therefore, researchers are always looking for new methods to obtain a green dyeing system. In this research, the use of the enzymatic dyeing method to prevent environmental pollution with metals and reduce production costs has been proposed. After degumming and bleaching, raw silk fabrics were dyed with natural dyes (Madder and Sumac) by three methods (pre-mordanting with a metal salt, one-step enzymatic dyeing, and two-step enzymatic dyeing). Results show that silk dyed with natural dyes by the enzymatic method has higher color strength and colorfastness than the pretreated with a metal salt. Also, the amount of remained dyes in the dyeing wastewater is significantly reduced by the enzymatic method. It is found that the enzymatic dyeing method leads to improvement of dye absorption, color strength, soft hand, no change in color shade, low production costs (due to low dyeing temperature), and a significant reduction in environmental pollution.

Keywords: eco-friendly, natural dyes, silk, traditional dyeing

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Authors: Onuoha Ogbonnaya Gideon, Ishaq Hafsah Yusuf

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Introduction: Meat is a perishable food of good nutrition. Meat ranks among the most significant, nutritious, and favored food items available to most locals. It is a good source of protein (17-19%), depending on sources, and contains appreciable amounts of fat and moisture. However, it has a very short shelf life due mainly to its high moisture, fat, and other nutrient contents. Meat spoilage can result from microbial proliferation as well as inherent enzymes in the meat tissues. Bacteria contamination and permeability to both oxygen and water vapor are major concerns associated with spoilage of meat and its storage. Packaging is fundamental in the preservation and presentation of food. Red clay is a very common substance; hydrous aluminum phyllosilicate, sometimes with varying amounts of iron, magnesium, alkali metals, alkaline earth, and cation formed from sedimentary rocks. Furthermore, red clay is an extremely absorbent material and develops plasticity when wet due to the molecular film of water surrounding the clay particles but can become hard, impervious, brittle, and non-brittle and non-plastic when dry. In developing countries, the high cost of refrigeration technologies and most other methods of preserving meat are exorbitant and thus can be substituted with the less expensive and readily available red clay for the preservation of meat. Methodology: 1000g of lean meat was diced into cubes of 10g each. The sample was then divided into four groups labelled raw meat (RMC); raw in 10% brine solution (RMB), boiled meat (BMC), and fried meat (FMC). It was then encapsulated with 2mm thick red clay and then heated in a muffle furnace at a temperature of 600OC for 30min. The samples were kept on a bench top for 30 days, and a storage study was carried out. Results: Our findings showed a decrease in value during storage for the physiochemical properties of all the sample; pH values decreased [RMC (7.05-7.6), RMB (8.46-7.0), BMC (6.0-5.0), FMC (4.08-3.9)]; free fatty acid content decreased with storage time [RMC (32.6%-31%), RMB (30.2%-28.6%), BMC (30.5%-27.4%), FMC (25.6%-23.8%)]; total soluble solid value decreased [RMC16.20-15.07, RMB (17.22-16.04), BMC (17.05-15.54), FMC (15.3-14.9)]. Conclusion: This result shows that encapsulation with red clay reduced all the values analyzed and thus has the potential to extend the shelf life of stored meat.

Keywords: red clay, encapsulating, shelf life, physicochemical properties, lean meat

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Authors: Muhammad Waqar Ashraf

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Selected heavy metals, namely Cu, Zn, Fe, Mn, Cd, Pb, and As, in seven popular varieties of edible vegetable oils collected from Saudi Arabia, were determined by graphite furnace atomic absorption spectrometry (GF-AAS) using microwave digestion. The accuracy of procedure was confirmed by certified reference materials (NIST 1577b). The concentrations for copper, zinc, iron, manganese, lead and arsenic were observed in the range of 0.035 - 0.286, 0.955 - 3.10, 17.3 - 57.8, 0.178 - 0.586, 0.011 - 0.017 and 0.011 - 0.018 µg/g, respectively. Cadmium was found to be in the range of 2.36 - 6.34 ng/g. The results are compared internationally and with standards laid down by world health agencies. A risk assessment study has been carried out to assess exposure to these metals via consumption of vegetable oils. A comparison has been made with safety intake levels for these heavy metals recommended by Institute of Medicine of the National Academies (IOM), US Environmental Protection Agency (US EPA) and Joint FAO/WHO Expert Committee on Food Additives (JECFA). The results indicated that the dietary intakes of the selected heavy metals from daily consumption of 25 g of edible vegetable oils for a 70 kg individual should pose no significant health risk to local population.

Keywords: vegetable oils, heavy metals, contamination, health risk assessment

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Authors: Pheiroijam Pooja, P. Chinnamuthu

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A novel vertical 1D In2O3/TiO2 nanocolumn (NC) axial heterostructure has been successfully synthesized using Glancing Angle Deposition (GLAD) technique inside E-Beam Evaporator chamber. Field emission scanning electron microscope (FESEM) has been used to evaluate the morphology of the structure grown. The estimated length of In2O3/TiO2 NC is ~250 nm and ~300nm for In2O3 and TiO2 respectively with diameter ~60-90 nm. The surface of the heterostructure is porous in nature which can affect the interfacial wettability properties. The grown structure has been further characterized using X-ray Diffraction (XRD) and UV-Visible absorption measurement. The polycrystalline nature of the sample has been examined using XRD with prominent peaks obtained with phase (101) for anatase TiO2 and (211) for In2O3. Here, 1D axial heterostructure NC thus favors efficient segregation of photo-excited carriers due to their type II band alignment between the constituent materials. Moreover, the 1D nanostructure is known for their large surface area and excellent ionic charge transport property. On exposure to UV light illumination, the surface properties of In2O3/TiO2 NC changes whereby the hydrophobic nature of the heterostructure changes to hydrophilic. As a result, the reversible surface wettability of heterostructure on interaction with UV light can give potential applications as antifogging and self-cleaning surfaces.

Keywords: GLAD, heterostructure, In2O3/TiO2 NC, surface wettability

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Authors: Nety Trisnawaty, Mirna Febriani

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The use of stainless steel wires in the field of dentistry is widely used, especially for orthodontic and prosthodontic treatment using stainless steel wire. The oral cavity is the ideal environment for corrosion, which can be caused by saliva. Prevention of corrosion on stainless steel wires can be done by using an organic or non-organic corrosion inhibitor. One of the organic inhibitors that can be used to prevent corrosion is black tea leaves extracts. To explain the comparison of chromium ions release for stainlees steel between artificial saliva and black tea leaves extracts. In this research we used artificial saliva, black tea leaves extracts, stainless steel wire and using Atomic Absorption Spectrophometric testing machine. The samples were soaked for 1, 3, 7 and 14 days in the artificial saliva and black tea leaves extracts. The results showed the difference of chromium ion release soaked in artificial saliva and black tea leaves extracts on days 1, 3, 7 and 14. Statistically, calculation with independent T-test with p < 0,05 showed a significant difference. The longer the duration of days, the more ion chromium were released. The conclusion of this study shows that black tea leaves extracts can inhibit the corrosion rate of stainless steel wires.

Keywords: chromium ion, stainless steel, artificial saliva, black tea leaves extracts

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Authors: A. Burakowska, M. Piotrowski, M. Kubicki, H. Trzaskowska, R. Sosnowiec, B. Myslek-Laurikainen

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The most important source of atmospheric radioactivity are radionuclides generated as a result of the impact of primary and secondary cosmic radiation, with the nuclei of nitrogen oxygen and carbon in the upper troposphere and lower stratosphere. This creates about thirty radioisotopes of more than twenty elements. For organisms, the four of them are most important: ³H, ⁷Be, ²²Na, ¹⁴C. The natural radionuclides, which are present in Earth crust, also settle on dust and particles of water vapor. By this means, the derivatives of uranium and thorium, and long-life 40K get into the air. ¹³⁷Cs is the most widespread isotope, that is implemented by humans into the environment. To determine the concentration of radionuclides in the atmosphere, high volume air samplers were used, where the aerosol collection took place on a special filter fabric (Petrianov filter tissue FPP-15-1.5). In 2002 the high volume air sampler AZA-1000 was installed at the Polish Polar Observatory of the Polish Academy of Science in Hornsund, Spitsbergen (77°00’N, 15°33’E), designed to operate in all weather conditions of the cold polar region. Since 1991 (with short breaks) the ASS-500 air sampler has been working, which is located in Swider at the Kalinowski Geophysical Observatory of Geophysics Institute of the Polish Academy of Science (52°07’N, 21°15’E). The following results of radionuclides concentrations were obtained from both stations using gamma spectroscopy analysis: ⁷Be, ¹³⁷Cs, ¹³⁴Cs, ²¹⁰Pb, ⁴⁰K. For gamma spectroscopy analysis HPGe (High Purity Germanium) detector were used. These data were compared with each other. The preliminary results gave evidence that radioactivity measured in aerosols is not proportional to the amount of dust for both studied regions. Furthermore, the results indicate annual variability (seasonal fluctuations) as well as a decrease in the average activity of ⁷Be with increasing latitude. The content of ⁷Be in surface air also indicates the relationship with solar activity cycles.

Keywords: aerosols, air filters, atmospheric beryllium, environmental radionuclides, gamma spectroscopy, mid-latitude regions radionuclides, polar regions radionuclides, solar cycles

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Authors: Wannakorn Sangthongngam, Melissa Huerta, Jaewoo Kim, Doyeon Kim

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Continuous glucose monitoring systems are essential for diabetics to avoid health complications but come at a costly price, especially when insurance does not fully cover the diabetic testing kits needed. This paper proposes a noninvasive continuous glucose monitoring system to provide an accessible, low-cost, and painless alternative method of accurate glucose measurements to help improve quality of life. Using a light source with a wavelength of 850nm illuminates the fingertip for the photodetector to detect the transmitted light. Utilizing SeeDevice’s photon-assisted tunneling photodetector (PAT-PD)-based QMOS™ sensor, fluctuations of voltage based on photon absorption in blood cells are comparable to traditional glucose measurements. The performance of the proposed method was validated using 4 test participants’ transmitted voltage readings compared with measurements obtained from the Accu-Chek glucometer. The proposed method was able to successfully measure concentrations from linear regression calculations.

Keywords: continuous glucose monitoring, non-invasive continuous glucose monitoring, NIR, photon-assisted tunneling photodetector, QMOS™, wearable device

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Authors: Nurul Noraziemah Mohd Pauzi, Muhammad Fauzi Mohd Zain

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The rapid advance in the electronic industry has led to the increase amount of the waste cathode ray tube (CRT) devices. The management of CRT waste upon disposal haves become a major issue of environmental concern as it contains toxic elements (i.e. lead, barium, zinc, etc.) which has a risk of leaching if it is not managed appropriately. Past studies have reported regarding the possible use of CRT glass as a part of aggregate in concrete production. However, incorporating waste CRT glass may present an environmental risk via leachability of toxic elements. Accordingly, the preventive measures for reducing the risk was proposed. The current work presented the experimental results regarding potential leaching of toxic elements from four types of concrete mixed, each compromising waste CRT glass as coarse aggregate with different shape and properties. Concentrations of detected elements are measure in the leachates by using atomic absorption spectrometry (AAS). Results indicate that the concentration of detected elements were found to be below applicable risk, despite the higher content of toxic elements in CRT glass. Therefore, the used of waste CRT glass as coarse aggregate in hardened concrete does not pose any risk of leachate of heavy metals to the environment.

Keywords: recycled CRT glass, coarse aggregate, physical properties, leaching, toxic elements

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Authors: Amin H. Almasria, Rajai Z. Alrousanb, Al-Harith Manasrah

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The collapse of a light weight pedestrian bridges due to vehicle collision is investigated and studied in detail using a dynamic nonlinear finite element analysis. Typical bridge widely used in Jordan is studied and modeled under truck collision using one dimensional beam finite element in order to minimize analysis time due to the dynamic nature of the problem. Truck collision with the bridge is simulated at different speeds and locations of collisions using dynamic explicit finite element scheme with material nonlinearity taken into account. Energy absorption of bridge is investigated through principle of energy conservation, where truck kinetic energy is assumed to be stored in the bridge as strain energy. Weak failure points in the bridges were identified, and modifications are proposed in order to strengthen the bridge structure and prevent total collapse. The proposed design modifications on bridge structure were successful in allowing the bridge to fail locally rather than globally and expected to help in saving lives.

Keywords: finite element method, dynamic impact, pedestrian bridges, strain energy, collapse failure

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Authors: Duy M. P. Vo, Cornelia Sennewald, Gerald Hoffmann, Chokri Cherif

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The development of solutions to improve the resistance of buildings to short-term dynamic loads, particularly impact load, is driven by the urgent demand worldwide on securing human life and critical infrastructures. The research training group GRK 2250/1 aims to develop mineral-bonded composites that allow the fabrication of thin-layered strengthening layers providing available concrete members with enhanced impact resistance. This paper presents the development of 3D woven wire cellular structures that can be used as innovative reinforcement for targeted composites. 3D woven wire cellular structures are truss-like architectures that can be fabricated in an automatized process with a great customization possibility. The specific architecture allows this kind of structures to have good load bearing capability and forming behavior, which is of great potential to give strength against impact loading. An appropriate combination of topology and material enables an optimal use of thin-layered reinforcement in concrete constructions.

Keywords: 3D woven cellular structures, ductile behavior, energy absorption, fiber-based reinforced concrete, impact resistant

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Authors: Imen Salhi, Salah Bouhlel, Bernrd Lehmann

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The Kebbouch South Pb-Zn deposit is located 20 km to the east of El Kef (NW) in the southeastern part of the Triassic diapir belt in the Tunisian Atlas. The deposit is composed of sulfide and non-sulfide zinc-lead ore bodies. The aim of this study is to provide petrographic results, mineralogy, as well as fluid inclusion data of the carbonate-hosted Pb-Zn Kebbouch South deposit. Mineralization forms two major ore types: (1) lenticular dolostones and clay breccias in the contact zone between Triassic and Upper Cretaceous strata;, it consists of small-scale lenticular, strata-or fault-controlled mineralization mainly composed of marcasite, galena, sphalerite, pyrite, and (2) stratiform mineralization in the Bahloul Formation (Upper Cenomanian-Lower Turonian) consisting of framboidal and cubic pyrite, disseminated sphalerite and galena. Non-metalliferous and/or gangue minerals are represented by dolomite, calcite, celestite and quartz. Fluid inclusion petrography study has been carried out on calcite and celestite. Fluid inclusions hosted in celestite are less than 20 µm large and show two types of aqueous inclusions: monophase liquid aqueous inclusions (L), abundant and very small, generally less than 15 µm and liquid-rich two phase inclusions (L+V). The gas phase forms a mobile vapor bubble. Microthermometric analyses of (L+V) fluid inclusions for celestite indicate that the homogenization temperature ranges from 121 to 156°C, and final ice melting temperatures are in the range of – 19 to -9°C corresponding to salinities of 12 to 21 wt% NaCl eq. (L+V) fluid inclusions from calcite are frequently localized along the growth zones; their homogenization temperature ranges from 96 to 164°C with final ice melting temperatures between -16 and -7°C corresponding to salinities of 9 to 19 wt% NaCl eq. According to mineralogical and fluid inclusion studies, mineralization in the Pb – Zn Kebbouch South deposit formed between 96 to 164°C with salinities ranging from 9 to 21 wt% NaCl eq. A contribution of basinal brines in the ore formation of the kebbouch South Pb–Zn deposit is likely. The deposit is part of the family of MVT deposits associated with the salt diapir environment.

Keywords: fluid inclusion, Kebbouch South, mineralogy, MVT deposits, Pb-Zn

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Authors: A. H. Jagaba, Musa Babayo, Ab Aziz Abdul Latiff, Sule Abubakar, I. M. Lawal, Isa Zubairu, M. A. Nasara

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Wastewater containing heavy metals is of extreme importance globally because of its potential threat to both the aquatic ecosystem and the soil environment. Heavy metal is hazardous even at low concentration and thereby causing various forms of diseases. One method which has been tested and found to be effective for heavy metals removal is coagulation-flocculation. For the coagulation process of POME obtained from Pertubuhan Peladang Negeri Johor (PPNJ), Oil Palm Mill Company located in Kahang area of Kluang, Johor Darul Takzim, Malaysia, diffèrent coagulants would be used to absorb and then separate the metals from wastewater. The determination of heavy metals concentration in POME was carried out using an inductively coupled plasma (ICP) and an Atomic Absorption Spectrometer (AAS). Results of the study showed that alum coagulant was successful in effectively reducing Cu, Cd, and Mn from 0.840 mg/l, 0.00509 mg/l and 8.191 mg/l to as low as 0.107 mg/l, 0.000270 mg/l and 0.612 mg/l respectively. All were obtained at a dose of 1000 mg/l. 1000 mg/l dose of ferric chloride reduced Pb concentration from 0.0248 mg/l to 0.00151 mg/l. Chitosan was best at reducing Fe and Zn from 62.91 mg/l and 3.616 mg/l to 6.003 mg/l and 0.595 mg/l all at a dose of 400 mg/l.

Keywords: palm oil mill effluent, coagulation, heavy metals, Pertubuhan Peladang Negeri Johor, Malaysia

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Authors: Y. Seki, A. Ç. Kılıç, M. Atagür, O. Özdemir, İ. Şen, K. Sever, Ö. Seydibeyoğlu, M. Sarikanat, N. Küçükdoğan

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Cheap and abundant waste materials have been investigated as filler materials in thermoplastic polymers instead of wood- based materials because of deforestation. Vine stem, as an agricultural waste, was used as a filler material for a thermoplastic polymer, high-density polyethylene (HDPE) in this study. Agricultural waste of vine stem was collected from Manisa region, Turkey. Vine stem at different rations was used to reinforce HDPE. The effect of vine stem loading on tensile strength and Young’s modulus of composites were obtained. It was clearly observed that tensile strength and Young’s modulus of HDPE was increased by vine stem loading. Thermal stabilities of composites were obtained by using thermogravimetric analysis. Water absorption behavior of HDPE was improved by loading vine stem into HDPE. The crystallinity index values of neat HDPE and vine stem loaded HDPE composites were investigated byX-ray diffraction analysis. From this study, it was inferred that vine stem, as an agricultural waste, can be used as a filler material for HDPE.

Keywords: waste filler, high density polyethylene, composite, composite materials

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Authors: Salihu Takuma

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Neem seed oil has high contents of unsaturated fatty acids which can be converted to epoxy fatty acids. The vegetable oil – based epoxy material are sustainable, renewable and biodegradable materials replacing petrochemical – based epoxy materials in some applications. Polystyrene is highly brittle with limited mechanical applications. Raw neem seed oil was obtained from National Research Institute for Chemical Technology (NARICT), Zaria, Nigeria. The oil was epoxidized at 60 0C for three (3) hours using formic acid generated in situ. The epoxidized oil was characterized using Fourier Transform Infrared spectroscopy (FTIR). The disappearance of C = C stretching peak around 3011.7 cm-1and formation of a new absorption peak around 943 cm-1 indicate the success of epoxidation. The epoxidized oil was blended with pure polystyrene in different weight percent compositions using solution casting in chloroform. The tensile properties of the blends demonstrated that the addition of 5 wt % ENO to PS led to an increase in elongation at break, but a decrease in tensile strength and modulus. This is in accordance with the common rule that plasticizers can decrease the tensile strength of the polymer.

Keywords: biodegradable, elongation at break, epoxidation, epoxy fatty acids, sustainable, tensile strength and modulus

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Authors: Ozan Kahraman, Hao Feng

Abstract:

Ultrasonic atomization (UA) is a useful technique for producing a liquid spray for various processes, such as spray drying. Ultrasound generates small droplets (a few microns in diameter) by disintegration of the liquid via cavitation and/or capillary waves, with low range velocity and narrow droplet size distribution. In recent years, UA has been investigated as an alternative for enabling or enhancing ultrasound-mediated unit operations, such as evaporation, separation, and purification. The previous studies on the UA separation of a solvent from a bulk solution were limited to ethanol-water systems. More investigations into ultrasound-mediated separation for other liquid systems are needed to elucidate the separation mechanism. This study was undertaken to investigate the effects of the operational parameters on the ultrasound-mediated separation of three miscible liquid pairs: ethanol-, methanol-, and butanol-water. A 2.4 MHz ultrasonic mister with a diameter of 18 mm and rating power of 24 W was installed on the bottom of a custom-designed cylindrical separation unit. Air was supplied to the unit (3 to 4 L/min.) as a carrier gas to collect the mist. The effects of the initial alcohol concentration, viscosity, and temperature (10, 30 and 50°C) on the atomization rates were evaluated. The alcohol concentration in the collected mist was measured with high performance liquid chromatography and a refractometer. The viscosity of the solutions was determined using a Brookfield digital viscometer. The alcohol concentration of the atomized mist was dependent on the feed concentration, feed rate, viscosity, and temperature. Increasing the temperature of the alcohol-water mixtures from 10 to 50°C increased the vapor pressure of both the alcohols and water, resulting in an increase in the atomization rates but a decrease in the separation efficiency. The alcohol concentration in the mist was higher than that of the alcohol-water equilibrium at all three temperatures. More importantly, for ethanol, the ethanol concentration in the mist went beyond the azeotropic point, which cannot be achieved by conventional distillation. Ultrasound-mediated separation is a promising non-equilibrium method for separating and purifying alcohols, which may result in significant energy reductions and process intensification.

Keywords: azeotropic mixtures, distillation, evaporation, purification, seperation, ultrasonic atomization

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Authors: Zhang Hui, Wu Caiqiu, Yuan Xuyin, Qiu Jie, Zhang Hanpei

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The heavy metal contaminations were determined with a detailed soil survey in roadside soils along Shenyang-Dalian Highway of Liaoning Province (China) and Pb, Cu, Cd, Ni and Zn were analyzed using the atomic absorption spectrophotometric method. The average concentration of Pb, Cu, Cd, Ni and Zn in roadside soils was determined to be 43.8, 26.5, 0.119, 32.1, 71.3 mg/kg respectively, and all of the heavy metal contents were higher than the background values. Different heavy metal distribution regularity was found in different land use type of roadside soil, there was an obvious peak of heavy concentration at 25m from road edge in the farmland, while in the forest and orchard soil, all heavy metals gradually decreased with the increase of distance from road edge and conformed to the exponential model. Furthermore, the heavy metal contents of heavy metals except Cd were markedly increased compared with those in 1999 and 2007, and the heavy metals concentrations of Shenyang- Dalian Highway were considered medium or low in comparison with those in other cities around the world. The assessment of heavy metal contamination of roadside soils illustrated a common low pollution for all heavy metal and recommended that more attention should be paid to Pb contamination in roadside soils in Shenyang-Dalian Highway.

Keywords: heavy metal contamination, roadside, highway, Nemerow Pollution Index

Procedia PDF Downloads 266

Authors: Esther Lorrayne M. Pereira, Adriana Souza M. Batista, Fabíola A. S. Ribeiro, Adelina P. Santos, Clascídia A. Furtado, Luiz O. Faria

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The combination of multi–walled carbon nanotubes (MWCNTs) with polymers offers an attractive route to reinforce the macromolecular compounds as well as the introduction of new properties based on morphological modifications or electronic interactions between the two constituents. As they are only a few nanometers in dimension, it offers ultra-large interfacial area per volume between the nano-element and polymer matrix. Nevertheless, the use of MWCNTs as a rough material in different applications has been largely limited by their poor processability, insolubility, and infusibility. Studies concerning the nanofiller reinforced polymer composites are justified in an attempt to overcome these limitations. This work presents one preliminary study of MWCNTs dispersion into the PVDF homopolymer. For preparation, the composite components were diluted in n,n-dimethylacetamide (DMAc) with mechanical agitation assistance. After complete dilution, followed by slow evaporation of the solvent at 60°C, the samples were dried. Films of about 80 μm were obtained. FTIR and UV-Vis spectroscopic techniques were used to characterize the nanocomposites. The appearance of absorption bands in the FTIR spectra of nanofilled samples, when compared to the spectrum of pristine PVDF samples, are discussed and compared with the UV-Vis measurements.

Keywords: composites materials, FTIR, MWNTs, PVDF, UV-vis

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Authors: Siti Hasnah Kamarudin, Luqman Chuah Abdullah, Min Min Aung, Chantara Thevy Ratnam

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The primary objective of this work was to develop fully nanocomposite material based on poly(lactic acid), epoxidized jatropha oil (EJO) and nanocrystalline cellulose. EJO was investigated as a sustainable alternative to petrochemical-based plasticizers to reinforce the ductility and toughness of plastics, in this case, nanocellulose/poly(lactic acid) (PLA). The EJO was melt blended into nanocellulose/PLA at concentrations from 1 wt% to 5 wt%. The blends were then hot-pressed into sheets to characterize their mechanical and physical properties. Microcrystalline cellulose had been converted to nanocrystalline cellulose by acid mercerisation technique and the effects thereof on the composites’ tensile, flexural, and impact properties, as well as their water absorption and density, were studied. The impact strengths of the nanocomposites were improved with the addition of NCC up to 0.5 wt%, with a maximum over 10 times that of the neat PLA. The flexural strength and modulus increased 4% and 50%, respectively, for NCC/PLA plasticized with EJO. This increase demonstrated the nanocrystalline cellulose addition gave notable improvements to the composites’ properties. Furthermore, analysis by scanning electron microscopy (SEM) of the nanocomposites’ tensile fracture surfaces indicated better interaction adhesion of the NCC/PLA plasticized with EJO compared with the PLA/EJO composites.

Keywords: nanocrystalline cellulose, nanocomposite, poly (lactic acid), epoxidised jatropha oil

Procedia PDF Downloads 148

Authors: Angela Vacaro de Souza, Fernando Ferrari Putti

Abstract:

One of the main plants cultivated in protected environment is tomato crop, which presents significant growth in its demand, because it is a tasty fruit, rich in nutrients and of high added value, however, poor management of fertilizers induces the process of soil salinization, causing several consequences, from reduced productivity to even soil infertility. These facts are derived from the increased concentration of salts, which hampers the process of water absorption by the plant, resulting in a biochemical and nutritional imbalance in the plant. Thus, this study aimed to investigate the effects of untreated and electromagnetically treated water in salinized soils on physical, physicochemical, and biochemical parameters in tomato fruits. The experiment was conducted at the Faculty of Science and Engineering, Tupã Campus (FCE/UNESP). A randomized complete block design with two types of treated water was adopted, with five different levels of initial salinity (0; 1.5; 2.5; 4; 5.5; 7 dS m⁻¹) by fertigation. Although the effects of salinity on fruit quality parameters are evident, no beneficial effects on increasing or maintaining postharvest quality of fruits whose plants were treated with electromagnetized water were evidenced.

Keywords: Solanum lycopersicum, soil salinization, protected environment, fertigation

Procedia PDF Downloads 117

Authors: Maria E. Fortună, Elena Ungureanu, Răzvan Rotaru, Valeria Harabagiu

Abstract:

Polymers are used in a variety of areas due to their unique mechanical and chemical properties. Natural polymers are biodegradable, whereas synthetic polymers are rarely biodegradable but can be modified. As a result, by combining the benefits of natural and synthetic polymers, composite materials that are biodegradable can be obtained with potential for biomedical and environmental applications. However, because of their strong resistance to degradation, it may be difficult to eliminate waste. As a result, interest in developing biodegradable polymers has risen significantly. This research involves obtaining and characterizing two biodegradable poly-ε-caprolactone-polydimethylsiloxane copolymers. A comparison study was conducted using an aminopropyl-terminated polydimethylsiloxane macroinitiator with two distinct molecular weights. The copolymers were obtained by ring-opening polymerization of poly (ɛ-caprolactone) in the presence of aminopropyl-terminated polydimethylsiloxane as initiator and comonomers and stannous 2-ethylhexanoate as a catalyst. The materials were characterized using a number of techniques, including NMR, FTIR, EDX, SEM, AFM, and DSC. Additionally, the water contact angle and water vapor sorption capacity were assessed. Furthermore, the copolymers were examined for environmental susceptibility by conducting biological tests on tomato plants (Lypercosium esculentum), with an accent on biological stability and metabolism. Subsequent to the copolymer's degradation, the dynamics of nitrogen experience evolutionary alterations, validating the progression of the process accompanied by the liberation of organic nitrogen. The biological tests performed (germination index, average seedling height, green and dry biomass) on Lypercosium esculentum, San Marzano variety tomato plants in direct contact with the copolymer indicated normal growth and development, suggesting a minimal toxic effect and, by extension, compatibility of the copolymer with the environment. The total chlorophyll concentration of plant leaves in contact with copolymers was determined, considering the pigment's critical role in photosynthesis and, implicitly, plant metabolism and physiological state.

Keywords: biodegradable, biological stability, copolymers, polydimethylsiloxane

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Authors: Fedda Y. Alzoubi, Ihsan A. Aljarrah

Abstract:

Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in different applications, especially in biomedical applications. Samples of different alkaline water were prepared in order to study the effect of alkalinity of water on the optical properties, size, and morphology of colloidal AgNPs prepared according to the chemical reduction method using the prepared water samples. Ultraviolet-Visible spectrophotometer, Zeta-sizer, and Scanning electron microscope (SEM) have been utilized to carry out this study. Absorption spectra AgNPs in different alkaline water show a surface Plasmon resonance (SPR) peak at the wavelength of 420 nm. The position of this peak is sensitive to the shape of the particles, and in our case, it indicates that the particles are spherical. As the alkalinity increases, the intensity of the SPR peak decreases, indicating the aggregation of particles. Zeta-sizer measurements show that the average diameter for AgNPs in pure water is found to be 53.51 nm, and this value increases as the alkalinity increases. Zeta potential values of samples show that the negatively coated particles are stable in the solution. SEM images insure the spherical shape of the prepared nanoparticles and show that as the alkalinity increases the particles aggregate into larger particles.

Keywords: aggregation, alkalinity, colloid, nanoparticle

Procedia PDF Downloads 127