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Due to outstanding properties of γ–TiAl intermetallic such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration, high working temperature and also its application in aerospace and automotive industry, turbojet engines and blade manufacturing; in this paper, electrical discharge machining (EDM) of γ–TiAl intermetallic by means of three kinds of tool electrodes including copper, graphite and aluminum is investigated, to compare the output characteristics of the machining process such as material removal rate, tool wear ratio, surface roughness and topography and EDS elemental analysis of machined surfaces. The results indicate that major elements in chemical composition of γ–TiAl machined surfaces are including titanium, aluminum, carbon and oxygen. The variation of tool material has not significant effect on formation of different chemical compounds and phases or in other words surface modification of machined surface. While it mainly affects other aspects of output characteristics such as material removal rate, tool wear ratio and surface roughness.

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Damping-off disease caused by Phytophthora melonis is the most common disease of cucumber seedlings Cucumis sativus L.. To study the efficacy of 8-hydroxy quinoline sulfate (Beltanol^®) in control of cucumber damping-off disease, glasshouse experiments were carried out with six treatments at research stations in Tehran, Alborz, and Semnan provinces in Iran. Treatments included 0.3, 0.4, and 0.5 ml∙l^-1 of Beltanol as the experimental fungicide, metalaxyl+mancozeb (Rosalaxyl^® WP 72%; FRAC code 3 + M03) at 2 g∙l^-1 as the standard fungicide along with inoculated and untreated and non-inoculated (healthy) controls. Cucumbers were cultivated from seed in trays, and treatments were applied twice. Once after seed sowing and second time at the 2-leaf stage. Disease incidence was recorded at the 4-leaf stage. Beltanol at 0.3 ml∙l^-1 had the least effect among fungicides, with nearly 50% of treated plants showing signs of disease. Application of Beltanol at 0.4 and 0.5 ml∙l^-1 decreased disease incidence by 59.55 and 64.47% compared to the inoculated control, respectively. Rosalaxyl^® performed better than Beltanol and reduced disease by 83.55%. However, to provide alternatives for proper fungicide rotations, Beltanol at the rate of 0.4 ml∙l^-1 may manage damping-off disease in cucumber.

 

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Due to widespread use of nanoparticles in various fields and the possibility of entering these nanoparticles into aquatic ecosystems, it is necessary to study the effects of these nanoparticles on surrounding environment. Artemia salina nauplii as a suitable biological model in ecotoxicology were exposed to different concentrations of 0.0001, 0.001, 0.005, 0.01 and 0.1 ppm mercury ions separately and simultaneously with a constant concentration of 0.1 ppm and 1 ppm titanium dioxide nanoparticles. The mortality rate of Artemia after 48 hours and the effects of these contaminants on fatty acid profile of Artemia were investigated. Artemia mortality in co-exposure treatment showed a dual effect. The mortality in the simultaneous exposure with constant concentration of 0.1ppm titanium dioxide increased compared with separate treatment of mercury. The mortality in simultaneous treatment with constant concentration of 1ppm titanium dioxide decreased compared with the separate treatment of mercury and the effect of mercury toxicity was reduced. Also, a decrease in saturated fatty acids was observed in the simultaneous exposure of mercury and titanium dioxide nanoparticles with a constant concentration of 1ppm compared with the separate treatment of mercury. The amount of monounsaturated and polyunsaturated fatty acids in the simultaneous exposure with constant concentration of 1ppm titanium dioxide was equal to control and increased compared with separate treatment of mercury. Present findings indicate the necessity of paying more attention to the potential interactions of pollutants in aquatic ecosystems and the effects of these interactions on the bioavailability and toxicity of pollutants regarding their concentration.

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Adsorption of Pb²⁺ from contaminated milk by NaOH treated orange peel due to lead contamination of pasturage, adosorption of Pb²⁺ from contaminated cow milk was investigated by innocuous NaOH treated orange peel. At first. Adsorption of Pb²⁺ was studied in aqueous solution contaminating 50ppm of Pb²⁺. Effect of adsorbent dose was considered in three different doses (1,2,4 g/l) temperature and particle size had no effect on Pb²⁺ biosorption. When pH has increased from 2 to 5.5 Pb²⁺ adosorption has augmented too. Continuing this work, model solution with composition similar to milk was prepared. In this study, the effect of several parameters on adosorption of Pb²⁺  fram milk  model solution was measured by atomic absorption. Effect of adsorbent dose was considered in three different doses (5, 10,15,g/l). The data are better had no effect on the biosorption capacity of  NaOH treated orange peel. Also results show that the ion–excheng mechanism is prevailing in the adsorption of Pb²⁺from milk model solution.    

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Today, the continuous release of environmental pollutants into aquatic ecosystems has made these environments extremely vulnerable and turned them into a storage sites for these toxic substances, so it is necessary to investigate the effects of these pollutants on aquatic life. The present study was conducted with the aim of determining the toxicity of silver nitrate and observing the behavioral changes of Litopenaeus vannamei during its exposure. To determine the toxicity, the standard method of OECD was used. At first, the viability and survival of Litopenaeus vannamei were checked after two weeks of acclimatization to laboratory conditions, then by conducting preliminary tests, the actual lethality values ​​of silver nitrate were obtained. In order to determine the median lethal concentration, shrimps were exposed to concentrations of  0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 mg/L of silver nitrate for 96 h and their mortality were recorded daily every 24 h. The LC₅₀, LOEC, NOEC and MATC were calculated based on shrimp mortality. During the viability and survival test, no mortality were observed up to 96 hours, and the survival rate of shrimps was 100%. The value of LC₅₀, NOEC, LOEC and MATC were determined as 0.084, 0.02, 0.025 and 0.0084 mg/liter, respectively. In different concentrations of silver nitrate, shrimps showed behaviors such as abnormal swimming, fast movements of swimming legs, coming to the surface of the water, twisting the body around itself and eventually losing balance.

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The significance of mangrove species in the world is undeniable and planting artificial mangrove forests is a desirable solution to preserve mangroves. The mangroves provide us with superior ecological services and one of their main services is the bioremediation of heavy metals. Hence, this study aimed to assess the effects of artificial mangroves of Velayat Park of Bandar Abbas on the contamination, adsorption pattern and ecological risk of heavy metals in the sediment samples. Thirty samples were collected from two paralleled sampling sections included those without mangroves and containing mangroves. Each sampling area consisted of upper, middle and lower sections. After drying samples using an oven, the dried sediments were sieved by a 63-micrometer sieve and digested by nitric and hydrochloric acid mixture. The concentration of As, Cu, Fe, Ni, Pb, V, and Zn was determined using ICP. The studied factors suggested a high level of ecological risk for as and Pb and the highest risk was observed in the samples without mangroves and a lower risk was reported for samples containing mangroves. Comparing the results with sediment quality guidelines and other studies indicated a dangerous concentration of As. Pearson correlation coefficient values exhibited that artificial mangroves have significantly affected the adsorption pattern of heavy metals (p-Value < 0.05). The principal component analysis (PCA) showed that As and Pb are dominantly derived from oil products leakages and industrial sewages while Cu, Fe, Ni, V and Zn are predominantly derived from natural and geological sources.

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Metal foams are a new class of materials with interesting structural properties; however no comprehensive understanding of their inelastic behavior has been established yet. Since the experimental studies of these materials have their own limitations, there is a growing research interest towards the mesostructural modeling of these materials. Accordingly many researchers have been trying to generate realistic and representative numerical models of the foams and prepare computational labs in which different aspects of foams mechanical behavior can be thoroughly investigated. The following three kinds of mesostructures have been commonly employed: (1) models based on a unit cell or a building block, (2) random Voronoi diagrams, and (3) CAD structures provided by the X-ray micro-computed tomography. In the current study, the physically representative circle set Voronoi diagrams are employed to define the geometry of 2D metallic foams. It is assumed that the minimum and maximum radii of the circular generators are 0.5 and 1.5 mm, respectively. The first sample is generated using linear distribution of cell size while, compared to the first sample, the second and third specimens have less and more small cells. An extra specimen (the forth sample) is also created with the same structure of the first one unless its edges are straight. In the next step, the FE models of the specimens are created using second order Timoshenko beam elements. Finally, the effects of microstructural features (e.g. strut curvature and cell size distribution) on the initial yield surface, elastic properties, and failure modes of the foams are numerically investigated under various biaxial loading conditions. Displacement-controlled loading is used. A newly energy-based approach developed for the identification of initial yield points has been incorporated. The results show that: (a) the size of the initial yield surface is significantly influenced by the curvature of the cell struts, (b) in the principal stresses space, the initial yield surface is bigger in the tension-tension region, (c) for a constant relative density, the presence of more big cells in a sample increases the size of the yield envelope, and (d) the macroscopic yield properties of the specimens can be interpreted according the microscopic failure mechanisms of the plastic yielding, elasto-plastic buckling, and plastic hinging of the struts. Furthermore, it is found that the previously proposed energy-based method for the identification of yield initiation under multiaxial loading conditions has serious shortcomings and needs revision.

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γ–TiAl intermetallic has outstanding properties such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration and high working temperature. These intermetallics are applied in aerospace and automotive industry, turbojet engines and blade manufacturing. In this paper, powder mixed electrical discharge machining (PMEDM) of γ–TiAl intermetallic by means of different kinds of powders including Al, SiC, Gr, Cr and Fe is investigated to compare the output characteristics of the process such as surface roughness, tool wear rate, material removal rate and surface topography with each other. This is an experimental investigation, by means of die sinking EDM machine and a special tank for machining. The results indicate that, aluminum powder as the most appropriate kind of powder in the optimum particle concentration of 2 g/l, improves the surface roughness about 32% comparing with conventional EDM, decreases the tool wear rate about 19%, but decreases the material removal rate about 7.5% and also the Al powder leads to improving the machined surface topography and decreasing the surface defects and micro cracks.

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Friction Stir Welding (FSW) is a solid state welding method. Now, for joining the variety of materials, especially dissimilar metals, has many applications. This method has no restrictions on the fusion welding. In addition to its many advantages, including the joining of metals with different melting points. In this paper, a successfully joint between Al5050Aluminum alloys to AISI304 stainless steel was reported. Friction Stir Welding (FSW) process was used for joining these dissimilar materials. In friction stir welding many parameters such as tool rotational speed, feedrate, offset and pin profile were effective on microstructure and mechanical properties of weld nugget by. This paper is focused on the effect of tool rotational speed, feedrate and offset on tensile strength and micro-hardness. In addition, effect of annealing operations was investigated on microstructure and mechanical properties of the weld nugget. The elongation and tensile strength of the weld nugget were increased 100 and 9 percent respectively by the annealing process.

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Metalepsis, in its narratological sense, is a trope in which an unnatural relationship is built between different levels of narrative. The natural relationship between narrative levels is formed by the act of narrating; a character from one level becomes the narrator of another. The term “Metalepsis of topic and illustration” can be coined to name a similar trope. This trope has been used for centuries in Persian poetry. Every Image comprises a topic and an illustration. The topic is what is being talked about and the illustration is what the topic is compared to. When several images are present along together, two different levels are distinguishable: the level of the topic and the level of illustration. The natural relationship between these two levels is similarity and any other relationship will result in metalepsis. As in the narratological metalepsis, there is always a paradox in the metalepsis of topic and illustration. The effect of these two kinds of metalepsis is also similar and can be humorous, fantastic, or a mixture of the two.

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The physico-chemical parameters, nutrient status and heavy metal ions of Huluka and Alaltu Rivers of Ambo, Ethiopia were studied. Temperature, pH, electrical conductivity, CO2 content, total dissolved solids, hardness, dissolved oxygen, Ca2+, Mg2+, Cl-, nitrate, phosphate and sulphate have been determined along with selected heavy metals to assess the various water quality profiles along the rivers due to addition of various waste materials through anthropogenic activities. The majority of the parameters show an increasing trend progressing downstream and the declining quality of the rivers. The downstream samples have shown almost a three times increase in most of the measured physico-chemical parameters but fell within the recommended limits for drinking water except for dissolved oxygen and phosphate. Along the river course, most of the heavy metals fulfill the maximum permissible limit for drinking water according to the international standards except Cd and Mn.

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In order to produce shell parts with diffrents applications using the new method in sheet metal forming is inevitable. In this article is intruduced a new process that movement of forming tool is compeltely gradual and controlled. In this method can creat complicated shapes in sheet metal. Also in order to create movement of tool is used Computer numerical Controlled (CNC) machine. In this process with inserting a punch under the sheet and gradual movement of tool in the special path creates a deformation in accoddance to punch shape. In this research by using experimental tests and theoretical analysis (slab analysis) is presented a comprehensive study of the governing equations in process. With calculating of stress field can present applied load at tool and sheet. ge for Calculation of this force is a suitable gauge for choosing kind of CNC machine equipment, sheet type and etc. Also according to analysis results can make decision about the effect of immeasurable important parameters in this process.

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Gobiidae family fishes play a significant role in coastal ecosystems with mud beds and mangrove ecosystems and also play a key role in the food chain in these areas. They are known as a heavy metal biomarkers. The aim of this study was to investigate the metals cadmium, lead and nickel in the muscle of two species including Cryptocentrus cyanotaenia in Hormoz Island and Boleophthalmus dussumieri in the Bandar Kamir. A total number of 30 fishes, samples for each species were collected from selected area and after biometrics and preparation and digestion steps to determine the concentration of nickel, cadmium and lead metals were analyzed by atomic absorption spectrometry. In this study, comparisons were made between the concentration of metals with a maximum of 13.10±1.88 and a minimum of 2.85±1.20 µg/g, respectively for  lead and cadmium in the muscle of B. dussumieri. The highest and lowest values ​​of 12.13±1.96 and 2.86±0.83 respectively were recorded for lead and cadmium in C. cyanotaenia muscle. By examining the correlation between the concentrations of metals in the muscle of the species, it was found that there is a positive and significant relationship between the concentration of metals in the muscle and their biometry (total length and total weight). The results showed that the studied Gobiidae family fish are suitable biomarkers for nickel, cadmium and lead metals.
 

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In this study, a comprehensive assessment of the occurrence and spatial distribution of heavy metals including Nickel, Lead, Zinc, Copper, Cadmium and Chromium, as well as, TPHs in the surface sediments of the coastal areas and far from the coast of the Persian Gulf in Bushehr and Khuzestan provinces were performed to identify the possible sources of sediment contamination and determining the degree of pollution. Eight pollution indices were used to evaluate the quality of sediments in terms of heavy metal and TPH pollution. The investigated areas could be distinguished by a significant degree of heavy metal pollution of Nickel, Cadmium and Zinc. High concentrations of Nickel and Zinc were observed in stations around Nakhiloo, Bushehr. The comparison of average pollution indices between regions showed that both Bushehr and Khuzestan provinces, respectively, with the average of contamination degree (CD) (20.25 and 22.11), modified contamination degree (MCD) (3.38 and 3.69), pollution load index (PLI) (31.17 and 57.57), potential ecological risk index (PERI) (353.54 and 349.39) have a significant degree and risk of Nickel and Cadmium pollution, especially in Nakhiloo area, Bushehr. Investigating the spatial fluctuations of the concentration of TPHs in two provinces showed an increasing trend from Bushehr to Khuzestan. However, areas were located in no pollution or low pollution zonation and were safe from the adverse biological effects of TPHs. Comprehensive and impressive strategies to control and reduce these pollutions, especially in polluted areas, should be considered, so that the sources of these pollutions be managed.
 

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 The accumulation heavy metals in the soil poses a significant risk to the health of plants, animals, and human communities. This study investigated the effect of small amounts of iron, zinc, and copper salts on hemocyte abundance, nutritional indices, and biological characteristics of the Ephestia kuehniella Zeller in-vitro. Fourth instar larvae were treated with iron, zinc, and copper salts at 25, 50, and 100 mg/kg in 24 and 48 h intervals. Immunological assessments included total hemocyte count, plasmatocytes, granulocytes, and phenol oxidase enzyme activity. The results demonstrated significant changes in immunological parameters compared to the control group. Notably, iron and zinc at 100 mg/kg exhibited the significant increase in enzyme activity at both 24 and 48 h. Conversely, iron caused a significant decrease in the activity of this enzyme after 24 h at 50 mg/kg when compared to other treatments. In terms of nutritional indicators, copper metal salt at 25 mg/kg enhanced the relative growth rate compared to the control. This preliminary study highlights the significant impact of zinc, copper, and iron salts on the biological characteristics and immune response of E. kuehniella. These findings suggest that the incorporation of small amounts of these metals into the insect's diet can induce biological and physiological disorders.


 

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Aims: The primary aims of the current research were to quantify the levels of some elements in the edible tissue of Capoeta capoeta and to evaluate the potential health risks to consumers using THQ, TTHQ, and CR indices.
Methods:  For this purpose, samples of the mentioned fish species were taken along the Cheshme Kile River in Mazandaran province. A graphite atomic absorption spectrophotometer was employed to carry out the analysis of elements.
Findings: The mean levels of Cu, Co, Fe, and Ni elements were 0.039, 0.031, 4.451, and 0.987 µg.g^-1 ww, respectively. The mean concentrations of elements measured in the examined species were below the thresholds established by several international organizations, including the EPA, FDA, WHO, NOAA, and EC. The target hazard quotient levels ranged from 2.86 x 10^-4 to 267.9 x 10^-4, and estimated weekly intake levels varied from 37.43 x 10^-4 to 592.85 x 10^-4. Daily intake levels were between 0.0085 and 2.5313 mg.kg^-1.day^-1, while weekly intake levels ranged from 0.0595 to 17.7194 mg.kg^-1.week^-1.
Conclusion: Evaluating the measured contents against international benchmarks, along with the THQ, TTHQ, and CR_lim indices, suggests that consumers are unlikely to face any health risks. It is essential to acknowledge that this research represents the initial study on the health risk evaluation of these metals in this species. Therefore, future studies should evaluate and monitor the risks posed by various pollutants due to the consumption of this species in different aquatic ecosystems.

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Recently, the study of nano materials in different fields of engineering science has been widely performed. In fact, the study on the behaviour of mixtures of nano material with other materials is among the new horizons in engineering research works. In this paper the impact of nanoclay on consolidation behaviour of bentonite in the presence of heavy metal contaminant is investigated. For this purpose, different percentages of nanoclay were mixed with bentonite and were additionally mixed with different concentrations of copper nitrate. Then, the odometer experiments performed on these prepared homogeneous samples in order to study the consolidation and permeability variations of samples. The results of this study show that the presence of industrial nanoclay causes an increase on the osmotic settlement of samples at the heavy metal concentrations up to 30 cmol/kg-soil of copper nitrate in comparison to the settlement of bentonite. Furthermore, the addition of industrial nano-clay to bentonite causes an increase in permeability of sample in comparison to the permeability of bentonite. This difference is more noticeable at high concentration of heavy metal. In addition, with an increase in external pressure, the permeability of bentonite sample and mixtures of bentonite/nanoclay gets closer to each others. This behaviour has been attributed to the presence of clay particles with nano dimensions in the mixtures of nanoclay-bentonite, the cation exchange capacity (CEC) and specific surface area (SSA) variations of samples due to the presence of nanoclay. In other words, according to the results of this study in the process of settlement of mixtures of bentonite and nano clay in the presence and absence of heavy metals the cation exchange capacity and specific surface area have the significant role. In this regard at the low concentration of heavy metals at the effective stress less than 100 kPa, cation exchange capacity governs the soil behaviour. However, at the effective stress more than 100 kPa, specific surface area is the governing factor which controls soil consolidation performance. Once the concentration of heavy metal increases in which it overcomes the soil buffering capacity, the heavy metals will neutralize negative charge of clay particles. Therefore, the cation exchange capacity of soil will have low effect on the settlement behaviour of soil. In such a case the specific surface area governs soil settlement process. For this reason due to the larger surface area of nano clays, the possibility for the secondary consolidation of soil increases.

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In this paper, the role of isotropic and kinematic hardening models are discussed in cold forming of a U-channel considering the springback phenomenon. The effect of influential parameters on the springback is also studied. For this purpose, a cold roll forming machine was built using a milling machine. The effects of forming angle’s changes, sheet material, roll geometry and sheet thickness are studied experimentally and numerically. The results show that the isotropic work hardening model is more precise in prediction of the springback. 304 stainless steel and AISI 1015 are used in experimental verification. Comparison of the simulation results with experimental values demonstrates the accuracy of the modeling.