Search results for: heavy metal pollution

Authors: H. Aghayan, F. A. Hashemi, R. Yavari, S. Zolghadri

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In this work, a new composite adsorbent based on a mesoporous silica SBA-15 with platelet morphology and tin salt of tungstomolybdophosphoric (TWMP) acid was synthesized and applied for uranium adsorption from aqueous solution. The sample was characterized by X-ray diffraction, Fourier transfer infra-red, and N₂ adsorption-desorption analysis, and then, effect of various parameters such as concentration of metal ions and contact time on adsorption behavior was examined. The experimental result showed that the adsorption process was explained by the Langmuir isotherm model very well, and predominant reaction mechanism is physisorption. Kinetic data of adsorption suggest that the adsorption process can be described by the pseudo second-order reaction rate model.

Keywords: platelet SBA-15, tungstomolybdophosphoric acid, adsorption, uranium ion

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Authors: Szilvia Várallyay, Szilvia Veres, Éva Bódi, Farzaneh Garousi, Béla Kovács

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The agricultural environment is contaminated with heavy metals and other toxic elements, which means more and more threats. One of the most important toxic element is the arsenic. Consequences of arsenic toxicity in the plant organism is decreases the weight of the roots, and causes discoloration and necrosis of leaves. The toxicity of arsenic depends on the quality and quantity of the arsenic specialization. The arsenic in the soil and in the plant presents as a most hazardous specialization. A dicotyledon plant were chosen for the experiment, namely sunflower. The sunflower plants were grown in nutrient solution in different As(III) levels. The content of As, P, Fe were measured from experimental plants, using by ICP-MS.Negative correlation was observed between the higher concentration of As(V) and As(III) in the nutrition solution and the content of P in the sunflower tissue. The amount of Fe was decreasing if we used a higher concentration of arsenic (30 mg kg-1). We can tell the conclusion that the arsenic had a negative effect on the sunflower tissue P and Fe content.

Keywords: arsenic, sunflower, ICP-MS, toxicity

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Authors: W. Khati, Y. Guasmi

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The activity of acetylcholinesterase (AChE) was studied in freshwater fish exposed to two heavy metals lead and cadmium. Measurements were made after short exposures (4 and 7 days) at concentrations of 1, 5, and 7μg/L cadmium and 1.25, 2.25, and 5 mg/L of lead. Cadmium induced no significant increases in activity of AChE in the gills for the lowest dose. Except significant inhibition on 7 days. In muscle of Gambusia, under stress of metallic lead, the activity increases compared to the control are noted at 4 days of treatment and inhibitions to 7 days of exposure. The analysis of variance (time, treatment) indicates only a very significant time effect (p<0.05), and as for cadmium, a significant body effect (p<0.01) is recorded. This small fish sedentary, colonizing particularly quiet environments, polluted, can only be the ideal bioindicator of contamination and bioaccumulation of metals. The presence of lead and cadmium in the bodies of fish is a risk factor not only for the lives of these aquatic species, but also for the man who is the top predator at the end of the food chain.

Keywords: biomarkers, bioindicator, environmenlal health, metals

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Authors: Souhila Bendenia, Chahrazed Bendenia, Hanaa Merad-Dib, Sarra Merabet, Samia Moulebhar, Sid Ahmed Khantar

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Today, environmental pollution is a major concernworldwide, threateninghumanhealth. Various techniques have been used, includingdegradation, filtration, advancedoxidationprocesses, ion exchange, membrane processes, and adsorption. The latter is one of the mostsuitablemethods, usinghighly efficient materials. In this study, NaX zeolite was modified with Cu or Ni at various rates. Following ion exchange, the samples were characterized by XRD, BET and SEM/EDX. After characterization, the exchanged zeolites were used for adsorption of various pollutants as CO2. Different thermodynamic parameters were studied such as Qst. XRD results show that the most intense peaks characteristic of 13X persist after the exchange reaction for all samples. The SEM images of our samples have uniform and regular crystal shapes. The results show that ion exhange with Cu or Ni affect the textural properties of X zeolites and prove that the exchange zeolites can be used as an adsorbent for depollution.

Keywords: X zeolites (NaX), ion exchange, characterization, adsorption

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Authors: Katalin Bodor, Zsolt Bodor, Robert Szep

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The particulate matter (PM) smaller than 2.5 μm are less studied due to the limited availability of PM₂.₅, and less information is available on the health effects attributable to PM₁₀ in Central-Eastern Europe. The objective of the current study was to assess the human health risk and characterize the spatial and temporal variation of PM₂.₅ and PM₁₀ in eight Romanian regions between the 2009-2018 and. The PM concentrations showed high variability over time and spatial distribution. The highest concentration was detected in the Bucharest region in the winter period, and the lowest was detected in West. The relative risk caused by the PM₁₀ for all-cause mortality varied between 1.017 (B) and 1.025 (W), with an average 1.020. The results demonstrate a positive relative risk of cardiopulmonary and lung cancer disease due to exposure to PM₂.₅ on the national average 1.26 ( ± 0.023) and 1.42 ( ± 0.037), respectively.

Keywords: PM₂.₅, PM₁₀, relative risk, health effect

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Authors: Moor Avigail

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This research examines gender norms that underlie the propensity to commit sexual assault and to carry it out. Factors that have been shown to relate to such propensity will be enumerated and tied to their ramifications. These include sexual objectification of women, endorsement of gender-based rape myths blaming the victim, masculine entitlement, low empathy to victims, along with elevated empathy towards rapists. Heavy use of pornography as well as a misconstruing of the meaning of refusal to sex, have also been implicated. Additionally, a cutting-edge investigation, which we have just completed, examined what seems to occur in the perpetrator's mind during the assault. No research to date has ventured to uncover what essentially allows the rape to be carried out in real time, in the sense of what mental mechanisms go into operation in rapists during the assault itself. Our findings demonstrate that dehumanization and rationalization are pivotal. On the one hand, the perpetrator apparently allows himself to disregard the victim's humanity while simultaneously justifying his actions in relation to the victim's behavior.

Keywords: gender norms, gender psychology, sexual assault, gender

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Authors: Sameh M. Osman, El-Refaie Kenawy, Zeid A. Al-Othman, Mohamed H. El-Newehy, El-Saied A. Aly, Sherine N. Khattab, Ayman El-Faham

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Recently, there has been a huge interest in using cyanuric chloride in a wide range of functional group transformations, as Cyanuric chloride has temperature-dependent differential reactivity for displacement of chlorides with various nucleophiles In the present work, some copolymers based on s-triazine Unit were prepared by microwave-assisted synthesis. For comparison study, the copolymers were synthesized by the conventional method. Synthesized Copolymers were characterized by MP, IR, TGA, DSC and GPC. The result indicated that copolymers are thermally stable and in good in composition and yield. Further studies that involve the test for selected removal of transition elements such as Cu (II), Zn (II) and Mn (II). Moreover, the effects of the polymeric triazine derivatives containing different functional groups which expected to have a good thermal stability and char formation ability on thermal degradation and flame retardancy.

Keywords: flame retardants, heavy metals, microwave-assisted synthesis, s-triazine

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Authors: Taehan Bae

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In this paper, a class of length-biased Weibull mixtures is presented to model loss severity data. The proposed model generalizes the Erlang mixtures with the common scale parameter, and it shares many important modelling features, such as flexibility to fit various data distribution shapes and weak-denseness in the class of positive continuous distributions, with the Erlang mixtures. We show that the asymptotic tail estimate of the length-biased Weibull mixture is Weibull-type, which makes the model effective to fit loss severity data with heavy-tailed observations. A method of statistical estimation is discussed with applications on real catastrophic loss data sets.

Keywords: Erlang mixture, length-biased distribution, transformed gamma distribution, asymptotic tail estimate, EM algorithm, expectation-maximization algorithm

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Authors: Mansour Fakhri, Monire Zokaei

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Where there are many demolitions on conventional asphalt pavements, heavy costs are paid to repair and reconstruct the pavement roads annually. Recently some research has been done in order to increase the pavement life. Perpetual pavement is regarded as one of them which can improve the pavement life and minimize the maintenance activity and cost. In this research, ABAQUS which is a finite element software is implemented for analyzing and simulation of perpetual pavement. Viscoelastic model of material is used and loading wheel is considered to be dynamic. Effect of different parameters on pavement function has been considered. Because of high primary cost these pavements are not widely used. In this regard, life cost analysis was also carried out to compare perpetual pavement to conventional asphalt concrete pavement. It was concluded that although the initial cost of perpetual pavement is higher than that of conventional asphalt pavement, life cycle cost analysis during 50 years of service life showed that the performance of this pavement is better and the whole life cost of that is less.

Keywords: ABAQUS, lifecycle cost analysis, mechanistic empirical, perpetual pavement

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Authors: Elham Sharifineyestani, Mohammad Farshchin

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Tropical cyclones are one of the most expensive and deadliest natural disasters. They cause heavy rainfall and serious flash flooding that result in billions of dollars of damage and considerable mortality each year in the United States. Prediction of the frequency of tropical cyclone-induced rainfall events can be helpful in emergency planning and flood risk management. In this study, we have developed a machine-learning model to predict the exceedance frequencies of tropical cyclone-induced rainfall events in the United States. Model results show a satisfactory agreement with available observations. To examine the effectiveness of our approach, we also have compared the result of our predictions with the exceedance frequencies predicted using a physics-based rainfall model by Feldmann.

Keywords: flash flooding, tropical cyclones, frequencies, machine learning, risk management

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Authors: Samera Salimpour Abkenar

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In this work, silk yarns were treated using ß-cyclodextrin (ß-CD) and cross-linked with citric acid (CA) via pad-dry-cure method. Elemental and FESEM analyses confirmed the presence of ß-CD on the treated silk samples even after five washing cycles. Then, the treated samples were dyed using natural dyes (carrot, orange and tomato). Results showed that the color strength (K/S) of the treated samples had been markedly enhanced compared with the control sample (after treatment with metal mordant). Finally, the color strength (K/S value) and color fastness (fading, staining and light fastness) of the treated samples with ß-CD were investigated and compared.

Keywords: ß-cyclodextrin, dyeing, natural dyes, silk yarn

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Authors: Caroline M. B. De Araujo, Helenise A. Do Nascimento, Claudia J. Da S. Cavalcanti, Mauricio A. Da Motta Sobrinho, Maria F. Pimentel

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Oil production is often followed by the joint production of water and gas. During the journey up to the surface, due to severe conditions of temperature and pressure, the mixing between these three components normally occurs. Thus, the three phases separation process must be one of the first steps to be performed after crude oil extraction, where the water-oil separation is the most complex and important step, since the presence of water into the process line can increase corrosion and hydrates formation. A wide range of methods can be applied in order to proceed with oil-water separation, being more commonly used: flotation, hydrocyclones, as well as the three phase separator vessels. Facing what has been presented so far, it is the aim of this paper to study a system consisting of a three-phase separator, evaluating the influence of three variables: temperature, working pressure and separator type, for two types of oil (light and heavy), by performing two factorial design plans 23, in order to find the best operating condition. In this case, the purpose is to obtain the greatest oil flow rate in the product stream (m3/h) as well as the lowest percentage of water in the oil stream. The simulation of the three-phase separator was performed using Aspen Hysys®2006 simulation software in stationary mode, and the evaluation of the factorial experimental designs was performed using the software Statistica®. From the general analysis of the four normal probability plots of effects obtained, it was observed that interaction effects of two and three factors did not show statistical significance at 95% confidence, since all the values were very close to zero. Similarly, the main effect "separator type" did not show significant statistical influence in any situation. As in this case, it has been assumed that the volumetric flow of water, oil and gas were equal in the inlet stream, the effect separator type, in fact, may not be significant for the proposed system. Nevertheless, the main effect “temperature” was significant for both responses (oil flow rate and mass fraction of water in the oil stream), considering both light and heavy oil, so that the best operation condition occurs with the temperature at its lowest level (30oC), since the higher the temperature, the liquid oil components pass into the vapor phase, going to the gas stream. Furthermore, the higher the temperature, the higher the formation water vapor, so that ends up going into the lighter stream (oil stream), making the separation process more difficult. Regarding the “working pressure”, this effect showed to be significant only for the oil flow rate, so that the best operation condition occurs with the pressure at its highest level (9bar), since a higher operating pressure, in this case, indicated a lower pressure drop inside the vessel, generating lower level of turbulence inside the separator. In conclusion, the best-operating condition obtained for the proposed system, at the studied range, occurs for temperature is at its lowest level and the working pressure is at its highest level.

Keywords: factorial experimental design, oil production, simulation, three-phase separator

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Authors: Sara Khamseh, Elahe Sharifi

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321 alloy steel is austenitic stainless steel with high oxidation resistance and is commonly used to fabricate heat exchangers and steam generators. However, the low hardness and weak tribological performance can cause dangerous failures during industrial operations. The well-designed protective coatings on 321 alloy steel surfaces with high hardness and good tribological performance can guarantee their safe applications. The surface protection of metal substrates using protective coatings showed high efficiency in prevailing these problems. Carbon-based multicomponent coatings, such as metal-added amorphous carbon coatings, are crucially necessary because of their remarkable mechanical and tribological performances. In the current study, (Nb: Si: a-C) multicomponent coatings (a-C: amorphous carbon) were coated on 321 alloys using a balanced magnetron (BM) sputtering system at room temperature. The effects of the Si/Nb ratio on microstructure, mechanical and tribological characteristics of (Nb: Si: a-C) composite coatings were investigated. The XRD and Raman analysis results showed that the coatings formed a composite structure of cubic diamond (C-D), NbC, and graphite-like carbon (GLC). The NbC phase's abundance decreased when the C-D phase's affluence increased with an increasing Si/Nb ratio. The coatings' indentation hardness and plasticity index (H³/E² ratio) increased with an increasing Si/Nb ratio. The better mechanical properties of the coatings with higher Si content can be attributed to the higher cubic diamond (C-D) content. The cubic diamond (C-D) is a challenging phase and can positively affect the mechanical performance of the coatings. It is well documented that in hard protective coatings, Si encourages amorphization. In addition, THE studies showed that Nb and Mo can act as a catalyst for nucleation and growth of hard cubic (C-D) and hexagonal (H-D) diamond phases in a-C coatings. In the current study, it seems that fully arranged nanocomposite coatings contain hard C-D and NbC phases that embedded in the amorphous carbon (GLC) phase is formed. This unique structure decreased grain boundary density and defects and resulted in high hardness and H³/E² ratio. Moreover, the COF and wear rate of the coatings decreased with increasing Si/Nb ratio. This can be attributed to the good mechanical properties of the coatings and the formation of graphite-like carbon (GLC) structure with lamellae arrangement in the coatings. The complex and self-lubricant coatings are successfully formed on the surface of 321 alloys. The results of the present study clarified that Si addition to (Nb: a-C) coatings improve the mechanical and tribological performance of the coatings on 321 alloy.

Keywords: COF, mechanical properties, microstructure, (Nb: Si: a-C) coatings, Wear rate

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Authors: Seyda Donmez, Oya Aydin Urucu, Ece Kok Yetimoglu

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Solidified floating organic drop microextraction was used for a preconcentration method of trace amount of lead. The analyte was complexed with 1-(2-pyridylazo)-2-naphtol and 1-undecanol, acetonitrile was added as an extraction and dispersive solvent respectively. The influences of some analytical parameters pH, volumes of extraction and disperser solvent, concentration of chelating agent, and concentration of salt were optimized. Under the optimum conditions the detection limits of Pb (II) was determined. The procedure was validated for the analysis of NCS DC 73347a hair standard reference material with satisfactory result. The developed procedure was successfully applied to food and water samples for detection of Pb (II) ions.

Keywords: analytical methods, graphite furnace atomic absorption spectrometry, heavy metals, solidified floating organic drop microextraction

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Authors: Seyedeh Belin Tavakoly Sany, Rosli Hashim, Majid Rezayi, Aishah Salleh, Omid Safari

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The purpose of this paper is to describe the main characteristics of macroinvertebrate species in response to environmental forcing factors. Overall, 23 species of Mollusca, 4 species of Arthropods, 3 species of Echinodermata and 3 species of Annelida were identified at the 9 sampling stations during four sampling periods. Individual species of Mollusca constituted 36.4% of the total abundance, followed by Arthropods (27.01%), Annelida (34.3%) and Echinodermata (2.4%). The results of Kruskal-Wallis test indicated that a significant difference (p <0.05) in the abundance, richness and diversity of the macro-benthic community in different stations. The correlation analysis revealed that anthropogenic pollution and natural variability caused by these variations in spatial scales.

Keywords: benthic invertebrates, diversity, abundance, West Port

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Authors: Bjorn Kierulf, Arun Chundru

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Over the past decade, collegiate rocketry teams have emerged across the country with various goals: space, liquid-fueled flight, etc. A critical piece of the development of knowledge within a club is the use of so-called "sounding rockets," whose goal is to take in-flight measurements that inform future rocket design. Common measurements include acceleration from inertial measurement units (IMU's), and altitude from barometers. With a properly tuned filter, these measurements can be used to find velocity, but are susceptible to noise, offset, and filter settings. Instead, velocity can be measured more directly and more instantaneously using a pitot tube, which operates by measuring the stagnation pressure. At supersonic speeds, an additional thermodynamic property is necessary to constrain the upstream state. One possibility is the stagnation temperature, measured by a thermocouple in the pitot tube. The routing of the pitot tube from the nosecone tip down to a pressure transducer is complicated by the nosecone's structure. Commercial-off-the-shelf (COTS) nosecones come with a removable metal tip (without a pitot tube). This provides the opportunity to make custom tips with integrated measurement systems without making the nosecone from scratch. The main design constraint is how the nosecone tip is held down onto the nosecone, using the tension in a threaded rod anchored to a bulkhead below. Because the threaded rod connects into a threaded hole in the center of the nosecone tip, the pitot tube follows a winding path, and the pressure fitting is off-center. Two designs will be presented in the paper, one with a curved pitot tube and a coaxial design that eliminates the need for the winding path by routing pressure through a structural tube. Additionally, three manufacturing methods will be presented for these designs: bound powder filament metal 3D printing, stereo-lithography (SLA) 3D printing, and traditional machining. These will employ three different materials, copper, steel, and proprietary resin. These manufacturing methods and materials are relatively low cost, thus accessible to student researchers. These designs and materials cover multiple use cases, based on how fast the sounding rocket is expected to travel and how important heating effects are - to measure and to avoid melting. This paper will include drawings showing key features and an overview of the design changes necessitated by the manufacture. It will also include a look at the successful use of these nosecone tips and the data they have gathered to date.

Keywords: additive manufacturing, machining, pitot tube, sounding rocketry

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Authors: Hannachi Med Tahar, H. Djebaili, B. Daheche

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In this approach, we have tried to describe the flattening of welded tubes, and its experimental application. The test is carried out at the (National product processing company dishes and tubes production). Usually, the final products (tubes) undergo a series of non-destructive inspection online and offline welding, and obviously destructive mechanical testing (bending, flattening, flaring, etc.). For this and for the purpose of implementing the flattening test, which applies to the processing of round tubes in other forms, it took four sections of welded tubes draft (before stretching hot) and welded tubes finished (after drawing hot and annealing), it was also noted the report 'health' flattened tubes must not show or crack or tear. The test is considered poor if it reveals a lack of ductility of the metal.

Keywords: flattening, destructive testing, tube drafts, finished tube, Castem 2001

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Authors: Himanshu Payal, Sachin Maheshwari, Pushpendra S. Bharti

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Electrical discharge machining (EDM), a non-conventional machining process, finds wide applications for shaping difficult-to-cut alloys. Process modeling of EDM is required to exploit the process to the fullest. Process modeling of EDM is a challenging task owing to involvement of so many electrical and non-electrical parameters. This work is an attempt to model the EDM process using artificial neural network (ANN). Experiments were carried out on die-sinking EDM taking Inconel 825 as work material. ANN modeling has been performed using experimental data. The prediction ability of trained network has been verified experimentally. Results indicate that ANN can predict the values of performance measures of EDM satisfactorily.

Keywords: artificial neural network, EDM, metal removal rate, modeling, surface roughness

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Authors: Hamid Mohammadi, S. H. Eftekhar Afzali

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The irregular usage of chemical fertilizer cause different types of water and soil pollution and problems in health of human in past decades and organic fertilizer has been considered more and more. Mycorrhizal fungi have symbiosis with plant families and significantly effect on plant growth. Proper management of these symbiosis causes to reduce the usage of chemical fertilizers and absorb nutrition especially phosphor. Pistacia vera is endemic in Iran and is one of the most important products for this country. Considering special circumstances of pistachio orchards according to increasing salinity of water and soil and mismanagement of fertilizer reveals the necessity of the usage of Mycorrhizal fungi in these orchards.

Keywords: pistachio, mycorhiza, nutrition, salinity

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Authors: Elham Zamiri

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In this research, we have focused on numeral simulation of a fuel rod in order to examine distribution of heat temperature in components of fuel rod by Fluent software by providing steady state, single phase fluid flow, frequency heat flux in a fuel rod in nuclear reactor to numeral simulation. Results of examining different layers of a fuel rod consist of fuel layer, gap, pod, and fluid cooling flow, also examining thermal properties and fluids such as heat transition rate and pressure drop. The obtained results through analytical method and results of other sources have been compared and have appropriate correspondence. Results show that using heavy water as cooling fluid along with few layers of gas and pod have the ability of reducing the temperature from above 300 ^◦C to 70 ^◦C. This investigation is developable for any geometry and material used in the nuclear reactor.

Keywords: nuclear fuel fission, numberal simulation, fuel rod, reactor, Fluent software

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Authors: Goodarz Sabetian, Sajjad Moshfe

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Control system for hi-tech industries could be realized generally and deeply by a special document. Vast heavy industries such as power plants with a large number of I/O signals are controlled by a distributed control system (DCS). This system comprises of so many parts from field level to high control level, and junior instrument engineers may be confused by this enormous information. The key document which can solve this problem is “control configuration system diagram” for each type of DCS. This is a road map that covers all of activities respect to control system in each industrial plant and inevitable to be studied by whom corresponded. It plays an important role from designing control system start point until the end; deliver the system to operate. This should be inserted in bid documents, contracts, purchasing specification and used in different periods of project EPC (engineering, procurement, and construction). Separate parts of DCS are categorized here in order of importance and a brief description and some practical plan is offered. This article could be useful for all instrument and control engineers who worked is EPC projects.

Keywords: control, configuration, DCS, power plant, bus

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Authors: H. Mohammadi Majd, M. Jalali Azizpour, V. Tavaf, A. Jaderi

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In upsetting processes contact friction significantly influence metal flow, stress-strain state and process parameters. Furthermore, tribological conditions influence workpiece deformation and its dimensional precision. A viscoplastic constitutive law, the Anand model, was applied to represent the inelastic deformation behavior in upsetting process. This paper presents research results of the influence of contact friction coefficient on a workpiece deformation in upsetting process.finite element parameters. This technique was tested for three different specimens simulations of the upsetting and the corresponding material and can be successfully employed to predict the deformation of the upsetting process.

Keywords: friction, upsetting, barreling, Anand model

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Authors: Shruti Motiwale, Xianlin Zhou, Reuben H. Kraft

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Military and sports personnel are often required to wear heavy helmets for extended periods of time. This leads to excessive cyclic loads on the neck and an increased chance of injury. Computational models offer one approach to understand and predict the time progression of disc degeneration under severe cyclic loading. In this paper, we have applied an analytic non-linear damage evolution model to estimate damage evolution in an intervertebral disc due to cyclic loads over decade-long time periods. We have also proposed a novel strategy for inclusion of recovery in the damage model. Our results show that damage only grows 20% in the initial 75% of the life, growing exponentially in the remaining 25% life. The analysis also shows that it is crucial to include recovery in a damage model.

Keywords: cervical spine, computational biomechanics, damage evolution, intervertebral disc, continuum damage mechanics

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Authors: A. Alshebani, Y. Swesi, S. Mrayed, F. Altaher, I. Musbah

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Cs-type nanocomposite zeolite membrane was successfully synthesized on an alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm; cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.

Keywords: MFI membrane, nanocomposite, ceramic hollow fibre, CO2, ion-exchange

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Authors: Zh. Karaulova, D. Baizhigitov

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At the Aktogay deposit, the oxidized ore section has been developed since 2015; by now, the reserves of easily enriched ore are decreasing, and a large number of copper-poor, difficult-to-enrich ores has been accumulated in the dumps of the KAZ Minerals Aktogay deposit, which is unprofitable to mine using the traditional mining methods. Hence, another technology needs to be implemented, which will significantly expand the raw material base of copper production in Kazakhstan and ensure the efficient use of natural resources. Heap and dump bacterial recovery are the most acceptable technologies for processing low-grade secondary copper sulfide ores. Test objects were the copper ores of Aktogay deposit and chemolithotrophic bacteria Leptospirillum ferrooxidans (L.f.), Acidithiobacillus caldus (A.c.), Sulfobacillus Acidophilus (S.a.), which are mixed cultures were both used in bacterial oxidation systems. They can stay active in the 20-400C temperature range. These bacteria were the most extensively studied and widely used in sulfide mineral recovery technology. Biocatalytic acceleration was achieved as a result of bacteria oxidizing iron sulfides to form iron sulfate, which subsequently underwent chemical oxidation to become sulfate oxide. The following results have been achieved at the initial stage: the goal was to grow and maintain the life activity of bacterial cultures under laboratory conditions. These bacteria grew the best within the pH 1,2-1,8 range with light stirring and in an aerated environment. The optimal growth temperature was 30-33оC. The growth rate decreased by one-half for each 4-5°C fall in temperature from 30°C. At best, the number of bacteria doubled every 24 hours. Typically, the maximum concentration of cells that can be grown in ferrous solution is about 107/ml. A further step researched in this case was the adaptation of microorganisms to the environment of certain metals. This was followed by mass production of inoculum and maintenance for their further cultivation on a factory scale. This was done by adding sulfide concentrate, allowing the bacteria to convert the ferrous sulfate as indicated by the Eh (>600 mV), then diluting to double the volume and adding concentrate to achieve the same metal level. This process was repeated until the desired metal level and volumes were achieved. The final stage of bacterial recovery was the transportation and irrigation of secondary sulfide copper ores of the oxidized ore section. In conclusion, the project was implemented at the Aktogay mine since the bioleaching process was prolonged. Besides, the method of bacterial recovery might compete well with existing non-biological methods of extraction of metals from ores.

Keywords: bacterial recovery, copper ore, bioleaching, bacterial inoculum

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Authors: Sunil Mittal, Sukhpreet Singh, Hardeep Kaur

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The affinity of thiol group with heavy metals is a well-established phenomenon. The present investigation has been focused on electrochemical response of cysteine and thioredoxin against arsenite (As III) on indium tin oxide (ITO) electrodes. It was observed that both the compounds produce distinct response in free and immobilised form at the electrode. The SEM, FTIR, and impedance studies of the modified electrode were conducted for characterization. Various parameters were optimized to achieve As (III) effect on the reduction potential of the compounds. Cyclic voltammetry and linear sweep voltammetry were employed as the analysis techniques. The optimum response was observed at neutral pH in both the cases, at optimum concentration of 2 mM and 4.27 µM for cysteine and thioredoxin respectively. It was observed that presence of As (III) increases the reduction current of both the moieties. The linear range of detection for As (III) with cysteine was from 1 to 10 mg L⁻¹ with detection limit of 0.8 mg L⁻¹. The thioredoxin was found more sensitive to As (III) and displayed a linear range from 0.1 to 1 mg L⁻¹ with detection limit of 10 µg L⁻¹.

Keywords: arsenite, cyclic voltammetry, cysteine, thioredoxin

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Authors: Iris Vural Gursel, Andrea Ramirez

Abstract:

Effective utilization of lignin is an important mean for developing economically profitable biorefineries. Current literature suggests that large amounts of lignin will become available in second generation biorefineries. New conversion technologies will, therefore, be needed to carry lignin transformation well beyond combustion to produce energy, but towards high-value products such as chemicals and transportation fuels. In recent years, significant progress on catalysis has been made to improve transformation of lignin, and new catalytic processes are emerging. In this work, a techno-economic assessment of two of these novel conversion routes and comparison with more established lignin pyrolysis route were made. The aim is to provide insights into the potential performance and potential hotspots in order to guide the experimental research and ease the commercialization by early identifying cost drivers, strengths, and challenges. The lignin conversion routes selected for detailed assessment were: (non-catalytic) lignin pyrolysis as the benchmark, direct hydrodeoxygenation (HDO) of lignin and hydrothermal lignin depolymerisation. Products generated were mixed oxygenated aromatic monomers (MOAMON), light organics, heavy organics, and char. For the technical assessment, a basis design followed by process modelling in Aspen was done using experimental yields. A design capacity of 200 kt/year lignin feed was chosen that is equivalent to a 1 Mt/y scale lignocellulosic biorefinery. The downstream equipment was modelled to achieve the separation of the product streams defined. For determining external utility requirement, heat integration was considered and when possible gasses were combusted to cover heating demand. The models made were used in generating necessary data on material and energy flows. Next, an economic assessment was carried out by estimating operating and capital costs. Return on investment (ROI) and payback period (PBP) were used as indicators. The results of the process modelling indicate that series of separation steps are required. The downstream processing was found especially demanding in the hydrothermal upgrading process due to the presence of significant amount of unconverted lignin (34%) and water. Also, external utility requirements were found to be high. Due to the complex separations, hydrothermal upgrading process showed the highest capital cost (50 M€ more than benchmark). Whereas operating costs were found the highest for the direct HDO process (20 M€/year more than benchmark) due to the use of hydrogen. Because of high yields to valuable heavy organics (32%) and MOAMON (24%), direct HDO process showed the highest ROI (12%) and the shortest PBP (5 years). This process is found feasible with a positive net present value. However, it is very sensitive to the prices used in the calculation. The assessments at this stage are associated with large uncertainties. Nevertheless, they are useful for comparing alternatives and identifying whether a certain process should be given further consideration. Among the three processes investigated here, the direct HDO process was seen to be the most promising.

Keywords: biorefinery, economic assessment, lignin conversion, process design

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Authors: Parham Bakhtiari

Abstract:

The essence of Musical Impressionism is best captured in the compositions of Claude Debussy and Maurice Ravel. These two important individuals represent the core of this art form, with their piano compositions remaining significant, impactful, and commonly performed in contemporary times. Their piano works reflected a revolutionary compositional style that strayed from classical romanticism and drew heavy inspiration from Symbolist poets and Asian arts. Additionally, numerous technical applications are commonly utilized to exemplify the principles of impressionism style by composers who did not frequently use them in prior eras, resulting in effectively evoking impressionistic images through diverse sonorities. The goal of this study is to showcase the range of impressionistic elements and compositional techniques, such as dissonances, pentatonic and whole-tone scales, parallel movements, and polytonality, through an examination of their piano compositions.

Keywords: music, impressionism, Debussy, ravel, piano, composition

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Authors: A. Alshebani, Y. Swesi, S. Mrayed, F. Altaher, I. Musbah

Abstract:

Cs-type nanocomposite zeolite membrane was successfully synthesized on a alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm, cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.

Keywords: MFI membrane, CO2, nanocomposite, ceramic hollow fibre, ion-exchange

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Authors: Biswarup Mukherjee, Aniruddha Ghosal

Abstract:

In this paper, we propose a new technique for implementing a low power full adder using a set of GDI multiplexers. Full adder circuits are used comprehensively in Application Specific Integrated Circuits (ASICs). Thus it is desirable to have low power operation for the sub components. The explored method of implementation achieves a low power design for the full adder. Simulated results using state-of-art Tanner tool indicates the superior performance of the proposed technique over conventional CMOS full adder. Detailed comparison of simulated results for the conventional and present method of implementation is presented.

Keywords: low power full adder, 2-T GDI MUX, ASIC (application specific integrated circuit), 12-T FA, CMOS (complementary metal oxide semiconductor)

Procedia PDF Downloads 343