Due to their high hardness, high wear resistance and self-lubricating capability, electroless nickel-boron coatings have attracted much attention in recent years. Many researchers have reported that the surface structure of this coating is cauliflower-like but few others have reported a nodular structure. There are two different models to describe each surface structure. In the present research, using 2-level factorial model, the effect of ethylenediamine, ammonia and stabilizer concentrations on the thickness and surface structure were researched. Investigating the effect of the variables, both cauliflower-like and granular structures were gained which the cauliflower-like structure and granular structure were contributed to lower and higher plating rates respectively after discussion. In addition, in condition of a stable bath and a pore-free coating where the plating rate was high enough to make surface structure granular, increase in thickness led to the coarsening of surface structure. The maximum thickness of 49 μm was attained when ethylenediamine concentration was at its low level (70 mL/L) and ammonia and stabilizer concentrations were at their high levels (46 and 3.33 mL/L respectively). Also minimum thickness of 23 μm was achieved when ethylenediamine, ammonia and stabilizer concentrations were at their high levels (130, 46, 3.33 mL/L respectively).

Thin films Indium tin oxide (ITO) with various thicknesses, from 130-620nm, have been deposited on the thin glass substrates by RF sputtering using ITO ceramic (90% wt. In2O3 and 10% wt. SnO2) target, and subsequently annealed in vacuum at various temperatures. Electrical and optical characteristics of ITO samples, before and after annealing at different temperatures, were investigated by four point probe and UV/VIS/IR spectrophotometer. Structural properties of layers deposited at optimum temperature of 400˚C were analyzed by XRD. SEM analysis was used to investigate the morphology of the optimal surface layer. Results show that by increasing the thickness, crystalline structure varies, so that sheet resistance, resistivity and transparency of films vary. Layer deposited with 130nm (lower thickness) has 83.71% transmittance and 2.34×10-4Ωcm resistivity. In contrast, 620nm thickness film with 79.07% transparency has the lowest electrical resistivity about 1×10-4Ωcm at 400˚C. This layer can be used as an optimal film with 1.6 Ω/□ sheet resistance for many applications.

In this study, the effects of drying temperature and mechanical pressure on the surface structure and dynamical properties of polyaniline (PAni) were studied. PAni was synthesized through the aniline polymerization process in the presence of ammonium persulfate in acidic medium and normal methyl-2-pyrrolidine solution. The obtained solution was dipped on a substrate of quartz glass. Atomic force microscopy (AFM) analysis based on nano-indentation tests were used to determine the values of hardness, Young’s modulus and Poisson’s ratio of the films. The results of the analysis of the scanning electron microscope demonstrated that the surface morphology of the film is changed from a fiber-to-interconnected cross-linked networkby increasing the drying temperature. The transmission electron microscope analysis showed that the diameter of the fibers on the surfaces dried at 318 K and 418 K was 18 and 30 nm, respectively. AFM results showed that the mean surface roughness of PAni film at 318 K without mechanical pressure was 63 nm, while for the film pressed at 5 MPa was less than 35 nm. Thermo-mechanical analysis showed that the glass transition temperature of the PAni film prepared without mechanical pressure and the film pressed at 5 MPa were 386 K and 378 K, respectively. Investigating the temperature dependence and applied pressure on the film surface in determining the viscoelastic properties of the PAni nanostructured film can provide readers with appropriate information about the storage and loss modulus of the film and the activation energy of the polymer layer during the thermal decomposition process.

Water Treatment is among the most important water quality management criteria in recirculating aquaculture systems (RAS). Nitrogenous wastes are the main pollutants in RAS. Ion exchangers, namely zeolites and clays are widely used in wastewater treatment industries. Due to negative charges within their structural network, they are used frequenty. Through superficial modifications this process can be applied to remove anions as well as cations. In the present study, modification of superficial and layered structures of zeolite and clay were carried out using the organic compound, tetradecyltrimethylammonium bromide and different ambient conditions of temperature (10, 15 and 20oC) and pH (6.0, 6.5, 7.0, 7.5 and 8.0) were examined. Results showed that ambient factors such as temperature, pH, ion concentration, presence of excess anions and interfer ions could affect the extent of ion uptake. It was revealed that higher temperatures increased ion uptake by modified Bentonits. Temperature rise significantly affected nitrite uptake of both absorbents (p<0.05). Higher pH significantly influenced nitrate absorption of both absorbents in a positive manner, while in the case of nitrite it was not depicted. Results indicated that use of modified ion exchangers as a effective tool for anion uptake in RAS is feasible.

IntroductionAquaculture wastewaters when discharged to the environment or another receiving body of water can create serious problems. These effluents contain large amounts of harmful material such as organic compounds, anionic and cationic species, uneaten food and etc., which have undesirable effects on the health of aquatic ecosystems and aquaculture facilities. Aquaculture systems produce large quantities of nutrients (phosphorus and sulphate) that require treatment and/or disposal. Principal sources of aquaculture wastes are uneaten foods. The presence of trace amounts of phosphate (even less than 1 ppm) in treated wastewater is often responsible for eutrophication; particularly in lakes and slow moving rivers. Sulphate and phosphorus, discharged with these effluents, result in enhanced growth of organisms associated with eutrophication. However, regulatory agencies are becoming increasingly concerned over elevated sulfate concentrations in effluents, owing largely to its impact on the salinity of receiving waters. There are several methods to treat wastewater containing sulfate anions. The removal of the anion by means of adsorption on the activated carbon, neutralization with CaCO3, biological treatment, reverse osmosis and dialysis and ion exchange were studied. Aiming for the high quality of receiving waters in aquaculture systems, various techniques such as settling systems, centrifugal systems, mechanical filters (media filter and screen filter) and biological processes have been introduced and were applied. Inorganic ion exchanger materials such as zeolites are utilized to remove ammonia from fish raring facilities. Clay is another material that can be used as an ion exchange adsorbent. However, it is utilized very poorly in the existing aquaculture wastewater treatment facilities. The use of clay as anion exchanger in aquaculture has not been considered yet. After modification, clay is also capable of removing anions and other compounds with negative charges. In this study, by using a cationic surfactant TDTMA, and acid thermo activation methods, the surface of bentonite was changed and the capability of the exchanged clay for the adsorption of anionic compounds such as sulfate and phosphate from aquaculture effluent was analyzed.Materials and MethodsBentonite, natural clay, was acquired from Tabas Iran Co. in Tehran and was used without any further purification. All chemicals were of analytical reagent type and were used as received. The standard solutions were prepared using NaNO3, NaNO2, Na3PO4 and Na2SO4 salts in Milli-Q water.Fish culture system containing two 200-L fish tanks and a sump tank was designed and constructed. Each tank was stocked with 30 trout of 120g mean weight (9.37 Kg/m3). It also included a combined unit of sand and biological filter to remove faces and other suspended particles and biological inter-conversion of nitrogenous wastes, respectively. The X-Ray diffraction pattern of the mineral sample showed that the major clay material present in the sample is bentonite.The main mineralogical impurities are Quartz, hydrated silicates of sodium, calcium, magnesium and aluminum, Stellerite-(Na), Illite, Muscovite and Gypsum. The composition of bentonite in terms of its oxide forms provided by the manufacturer is listed in Table 1. Elemental analysis of the sample using XRF showed that the raw material had Si/Al ratio of 3.46. The Na-exchanged form of bentonite was prepared by stirring samples for 6h with a 1M aqueous solution of NaCl. Excess NaCl and other exchangeable cations were removed from the exchanged bentonite via filtering. Then, it was washed several times with deionized water until a negative chloride test was obtained with 0.1M AgNO3. The Na-saturated bentonite (50g) was dispersed in 1L of distilled water. TDTMA–bentonite was prepared by adding quantities of the respective surfactant equal to twice the cation exchange capacity of the bentonite and was stirred for 6h. After treatment, bentonite was washed with deionized water to obtain salt-free minerals and a negative chloride test was carried out with 0.1M AgNO3. Finally, it was dried, grounded and sieved to a size range of 0.8-1.2mm.The acid thermo activated clay was obtained from a natural sodium bentonite. The raw material was first decarbonated and homoionized. Acid thermo activation is a process that allows controlled extraction of aluminum ions from crystalline structure of clay, also introducing an acceptable acidity level. This process modifies the textural properties of clays, favoring a greater porosity and surface area. To carry out acid thermo activation, the purified clay was put in a flask with an acid solution (10 mL acid/1 g clay), stirred and refluxed and heated to 105°C for 3h. The utilized acid solution was: HNO3 (2N). Thereafter, the clay was washed with de-ionized water and dried at 70°C. The powders were ground to a particle size of 0.8-1.2mm and then heated for 4h at 300°C.The solution pH was carefully adjusted by adding small amounts of HCl or NaOH solutions and measured using a pH-meter (corning 120). The samples were filtered and the equilibrium concentrations ascertained by photometer (palintest® 8000). The amount of anions adsorbed onto TDTMA–Bentonite (SMB) was determined by the difference between the initial and remaining concentrations of anionic solutions. The distribution coefficient (Kd) was determined by using the following equation: Where Ci and Ce are the initial and the equilibrium anions concentrations (mg/L), V is the volume of solution (mL) and m is the amount of the used adsorbent (g).Results and Discussion Structural comparisons between modified and natural bentonite imply that modification procedures have changed crystal lattice and layered structure of the mineral smoothly (Figs. 3 and 4). Heating resulted in increased distance between layers and consequently yielded higher anion uptake compared with natural bentonite. Surfactant layer grafted on surface and within the layers of mineral resulted in anions removal by the modified bentonite.The present study was set out in a laboratory condition to evaluate the anion absorption capacity of surfactant acid thermo modified bentonites so as to reveal the potential of the compound as an alternative water remediation method for aquaculture recirculation system. The research clearly suggests that modified bentonite acts as a proper adsorbent for the removal of harmful anions from aquaculture and aqueous solutions. Because of the importance of generating a viable ion uptake tool for toxic species, different studies have been carried out regarding the use of a low-cost adsorbent for the selective removal of anions from aqueous solutions.ConclusionIt has been shown that bentonite modified by TDTMA and acid thermo activation method provides a considerable ion uptake capacity. The main advantages of this procedure are as follows:1- Natural bentonite is very cheap and abundant.Application of Modified Bentonites (SMB and ATB) for Decreasing… 122- Results showed that bentonite modified by TDTMA was efficient for removing harmful ions from aquaculture wastewater and decreasing anions under the critical levels.3- Since the bentonite clays even in modified forms can remove cationic species, so this adsorbent is very effective for the simultaneous removal of cationic and anionic species from aquaculture recirculation effluents. 4- This new adsorbent can be utilized as a supportive filter in RAS to remove toxic compounds such as NO3-, NO2-, PO43- and SO4 from aquaculture systems.

Nitrogenous compounds are the main anionic pollutants in recirculating aquaculture systems. Ion exchangers are vastly applied in waste water industry. Negative surface charge? of the zeolites and clays enable them for cation absorptions, however, they do not have any tendency for absorbing anion absorptions. Meanwhile, by modifying surface structure??, they can absorb anions. In the present study, modifications of superficial and layered structures of clays were carried out using the organic compound, tetradecyltrimethylammonium and heat treatment to enable the ion exchangers to absorb the nitrogenous anions from rearing system. Three different ambient temperatures (10, 15 and 20 °C) and different pHs (6, 6.5, 7, 7.5 and 8) were used. Results showed that environmental conditions influenced anionic adsorption. Nitrate and nitrite absorption from aquaculture effluent and nitrate from standard solution by two absorbent had significant effect by ambient temperature (P< 0.05). In aquaculture effluent, pH did not show any regular effect on nitrite absorption. It was inferred that environmental factors such as temperature, pH, anion concentration, presence of other ions and counter ions are effective on absorptive capability of a given ion. Results showed that modified ion exchangers might be useful for harmful anion absorption from recirculating aquaculture system.

In recent years, an effective recycling process from smoked cigarette butts is the main challenge for decreasing the worldwide environmental pollution. Therefore, low-cost activated carbon fibers (ACFs) are synthesized by a carbonization/ activation process derived from smoked cigarette filters, in which potassium hydroxide (KOH) acts as the chemical activation agent. The KOH-treated filters were added to a tube oven and heated at various rates and held at 800 °C for 1 h under a nitrogen atmosphere. The effects of various synthesis procedures on surface morphology, microstructure, and porosity of the synthesized ACFs were investigated. The surface morphology and microstructural analysis of ACFs displayed that the porous spots and oxygen-containing groups (COOH, –OH, and C=O) are formed on the surfaces of fibers. The obtained results displayed that the synthesized ACFs have developed porous structures with fibrous shapes. The ACFs with maximum carbon yield, surface area, and total pore volume of 29.41 %, 855 m2/g, and 0.7431 cm3/g were synthesized at a KOH concentration of 10 g/l, a heating rate of 2 °C/min, and carbonization temperature of 800 °C. This study presented an engineering process for the production of ACFs through recycling smoked cigarette butts with chemical activation protocol.

Oral iron drops are recommended for children aged 6-24 months to prevent iron-deficiency anemia. However, their use is associated with the potential risk of erosion and microhardness reduction of primary teeth enamel due to their high acidity. It seems that the combination of silicone oil, nano-hydroxyapatite and chitosan powder may be able to improve the microhardness and surface structure of primary teeth enamel. This study sought to assess the effect of silicone oil plus nano-hydroxyapatite/chitosan on the changed microhardness and surface structure of primary teeth enamel after exposure to iron drop. In this in-vitro study, 30 anterior deciduous teeth were collected and randomly divided into 3 groups. In the first group, samples were exposed to iron drop for 5min and then treated with nano-hydroxyapatite/chitosan and silicone oil for 10min. In the second group, specimens were first treated with the mentioned compound and then exposed to iron drop. Microhardness changes were compared in each group using Wilcoxon one sample or Sign test and between the two groups using Mann Whitney U test. The third group specimens were observed with a scanning electron microscope (SEM) to assess their surface texture and quality. In the first group, iron drop exposure decreased enamel microhardness by 44% of the baseline value (P<0.001). Application of the understudy compound after iron drop exposure significantly increased enamel microhardness by 3% of the baseline value (P=0.006). Use of the mentioned compound before iron drop exposure significantly increased enamel microhardness by 2% of the baseline value (P=0.023). No statistically significant difference was found between the two groups (P=0.74). Iron drop exposure significantly decreased enamel microhardness. Use of silicone oil and nano-hydroxyapatite/chitosan powder caused 3% and 2% increase in enamel microhardness in the first and 2nd group, respectively. These values, compared to the effect of iron drop exposure are clinically significant.

With the rise of new technologies in teaching foreign languages, it has become increasingly important to provide comprehensive and fundamental solutions to tackle the challenges of utilizing technology in teaching different language skills, specifically L2 reading comprehension. The objective of this study was to use transcendental phenomenology to investigate the experiences of English language teachers in Iran, and to uncover their effective solutions for addressing the challenges of teaching English reading comprehension in virtual classes. In this research, the experiences of eight English language teachers were examined using the transcendental phenomenology method to deal with the challenges of teaching English language comprehension. The results of analyzing narratives and phenomenological interviews utilizing Giorgi's five-step phenomenological analysis method (Giorgi, 2009) showed two solutions: 1) the importance of embedding new technologies in the growth of educational technology knowledge and 2) the importance of embedding new technologies in strengthening a positive attitude towards the use of technology, which can help to solve the challenges of teaching English reading comprehension in virtual classes. Based on the findings of this study, it can be concluded that the solutions to address the challenges of virtual teaching of English language comprehension are of interest in two structures: superficial and deep. Solutions in the surface structure, such as improving the Internet speed, may only address the challenges for a limited time and in certain environments. However, deep-level solutions that were the focus of this transcendental phenomenological research can solve the challenges more comprehensively due to their multifaceted nature.

The development of technology has significantly improved the teaching and learning process in today's society. Technology's unique features, such as its wide availability, ease of access at different times and places, and high speed, have contributed to its increased use in teaching and learning over the past two decades (Haleem et al., 2022). Given the importance of learning English in today's world, it is essential to use modern technologies to facilitate the teaching and learning process, especially in non-English-speaking countries (Cifuentes, 2022). Therefore, the use of modern technologies to improve teaching methods, tools, content, equipment, and new strategies is crucial to achieving educational goals in the field of English language education (Prayudi et al., 2021). 
Since reading comprehension is crucial for the academic progress of English language learners (Smith et al., 2021), using new technologies to teach reading comprehension can increase the participation of English language learners in virtual educational environments, improve their attitudes toward learning, and enhance their academic progress (Noordan et al., 2022). Therefore, the purpose of this research was to use transcendental phenomenology to investigate the experiences of English language teachers in Iran and discover their effective solutions to face the challenges of teaching reading comprehension in virtual environments and classrooms.

The researchers used transcendental phenomenology as a type of qualitative research to achieve the research's purpose of providing fundamental solutions to the challenges of teaching English language comprehension to non-English speakers in virtual environments based on teachers' experiences. This method pays attention to the experiences of teachers and leaves aside the experiences of researchers (Moustakas, 1994). By using transcendental phenomenology, the researchers could inform the participants about the goals of research, based on which they obtained more detailed information about teaching strategies without the challenge of understanding content in the virtual environment, which was based on the semantic description of the investigated phenomenon (Edmonds & Kennedy, 2017). The study included eight teachers of English to non-English speakers who were selected purposefully because they faced challenges with teaching reading comprehension in virtual classes and had provided solutions to overcome those challenges.

The obtained results showed multidimensional solutions from the teachers that could affect the existing challenges in a multifaceted and fundamental way. Based on this, two solutions were identified: 1) the importance of embedding new technologies in the growth of educational technology knowledge and 2) the importance of embedding new technologies in strengthening a positive attitude towards the use of technology. These effective solutions can provide fundamental solutions to the challenges of teaching English comprehension in virtual classes.

The findings of the study showed that the solutions to the challenges of virtual teaching of English language comprehension can be classified into two categories: superficial and deep structures. Superficial solutions, such as increasing internet speed, may solve some challenges for a limited period and in some environments. Still, deep-level solutions, such as the ones identified in this research, can solve challenges more effectively. For instance, by introducing new technologies in educational centers, teachers feel the need to strengthen their technology knowledge and act accordingly. At the same time, their positive attitude towards the use of technology is enhanced, which results from observing the usefulness of virtual education, and not a challenge. Thus, educational decision-makers are advised to make a special contribution to the foundation of new technologies to deal with the challenges of virtual education, particularly the challenges of virtual teaching of English language comprehension. Embedding new technologies in strengthening the positive attitude toward the use of technology and in the growth of educational technology knowledge can create a turning point in virtual education, solving many of the current challenges of virtual teaching by creating educational and implementation strategies.

The authors have no conflict of interest. 

We would like to express our gratitude to Imam Khomeini International University for providing financial support for this study.

Synesthesia (sensualism) is a kind of deviation from the norm of meaning, which by breaking the normal system of words and creating a concept contrary to the habit, creates literary pleasure in the audience. In this way of writing, the poet shatters the common mental system of the reader or listener by breaking the superficial structure of the words and not their deep structure and creates a new and pristine image to surprise the audience. In this essay, the authors, inspired by the analytical linguistics school of Lakoff and Johnson, have examined the prevalence of descriptive, analytical, and sensuous in Hafez's poems. The following article shows that the feeling in Hafez's poems, in addition to its different types of feeling; It implies different and different semantic concepts. One of the interesting methods in Hafez's poems is the emphasis on a special type of senses in sensing and transferring meaning from the source area to different areas of semantic purposes. By choosing this type of sensation, Hafez has increased the rhetorical and artistic texture of the speech, and in order to enhance the dignity and rank of tangible things and connect the mental and objective worlds, he has paid special attention to objective-abstract sensation.