The Structural Model of Relationship between Informational Style, Achievement Goals and Cognitive Engagement

As a critical period in people lives, teens’ period relies on two special aspects. In one hand it relates to the changes of believes about the ego. On the other hand, it relates to social and upbringing expectations. There is one unifying concept which unifies the changes and it’s the identity. Based on Brzezinski’s socio-cognitive perspective, identity is considered a theory of self. The self-theory is a conception structure of principles, values and criteria related to self which helps the person to adapt and cope with life problems especially the educational life. The self-theory may lead the teenager toward adaptive values, goals and motivations to make the teenager use one’s cognitive abilities for more success and cooperation. In this way, the purpose of this article is to offer a structural model for cognitive engagement based on informational style, mastery goal and performance-approach goals. The present study is a kind of non-experimental design. To speak more precisely, it is a type of correlations design which has analyzed a structural pattern of variables relationship. The sample size (the number of people taking part in study) is 630. The sample candidates are medical students of Sabzevar and Neyshaboor universities, who have been selected by a multi-stages/steps sampling process. Brzezinski identity style scales (IsI-3), Midgly et al achievement goal (PALS) and also motivational strategies for learning (MSLQ) were used to evaluate the research variables. The data were analyzed by structural pattern of the equations. The results indicated that informational style has got two effects on the cognitive engagement which are 1- A direct positive effect (0/23). 2-An indirect positive effect and more powerful (0/53) that indirect effect between two variable is through mastery goals (which is a mediator variable). Mastery goals make adolescent who have informational identity style and more purposeful in information searching. Mediator variable of mastery goals builds up stronger relationship between informational identity style and cognitive engagement

The Structural Model of Relationship between Informational Style, Achievement Goals and Cognitive Engagement

As a critical period in people lives, teens’ period relies on two special aspects. In one hand it relates to the changes of believes about the ego. On the other hand, it relates to social and upbringing expectations. There is one unifying concept which unifies the changes and it’s the identity. Based on Brzezinski’s socio-cognitive perspective, identity is considered a theory of self. The self-theory is a conception structure of principles, values and criteria related to self which helps the person to adapt and cope with life problems especially the educational life. The self-theory may lead the teenager toward adaptive values, goals and motivations to make the teenager use one’s cognitive abilities for more success and cooperation. In this way, the purpose of this article is to offer a structural model for cognitive engagement based on informational style, mastery goal and performance-approach goals. The present study is a kind of non-experimental design. To speak more precisely, it is a type of correlations design which has analyzed a structural pattern of variables relationship. The sample size (the number of people taking part in study) is 630. The sample candidates are medical students of Sabzevar and Neyshaboor universities, who have been selected by a multi-stages/steps sampling process. Brzezinski identity style scales (IsI-3), Midgly et al achievement goal (PALS) and also motivational strategies for learning (MSLQ) were used to evaluate the research variables. The data were analyzed by structural pattern of the equations. The results indicated that informational style has got two effects on the cognitive engagement which are 1- A direct positive effect (0/23). 2-An indirect positive effect and more powerful (0/53) that indirect effect between two variable is through mastery goals (which is a mediator variable). Mastery goals make adolescent who have informational identity style and more purposeful in information searching. Mediator variable of mastery goals builds up stronger relationship between informational identity style and cognitive engagement

Removal of sulfadimethoxine antibiotic from aqueous solutions using carbon nanotubes

Abstract Background and aim: Antibiotics are a category of organic pollutants that can cause serious environmental problems through their disposal and uncontrolled release to the environment. The purpose of this study was to investigate the removal of sulfadimethoxine from aqueous solutions using carbon nanotubes. Materials and Methods: The present work was an experimental study in which the effects of different parameters, such as PH, time, doses of carbon nanotubes, and different concentrations of sulfadimethoxine, on the removal of antibiotic from solutions were examined. All experiments were carried out in a 100-mL reactor at laboratory temperature (24 ± 2 ° C) using a magnetic stirrer at 350 rpm. Results: The results showed that the maximum removal efficiency (94.5%) was occurred at pH = 6, adsorbent dosage 0.04 g, contact time of 30 min, and initial concentration of 20 mg/L. The findings on the effect of pH showed that the adsorption capacity increases with increasing pH, and at pH = 6, it reaches its maximum and then decreases again. The extent of removal was increased by increasing the dose of carbon nanotubes and the optimum amount for initial concentration of 100 mg/L (50 mL) was 0.04 g. The amount of absorption increased with increasing contact time and the maximum absorption occurred when the contact time was 30 min. The sulfadimethoxine antibiotic isotherm followed the Langmuir isotherm model (R2 = 0.9800) and the pseudo-second-order kinetic model (R2 = 0.9937). Conclusion: The results showed that carbon nanotubes have a high potential for removal of sulfadimethoxine from aqueous solutions, due to its properties like its high surface area

Carbon quantum dot supported semiconductor photocatalysts for efficient degradation of organic pollutants in water: A review

Semiconductor photocatalyst mediated advanced oxidation processes are regarded as one of the most efficient technologies to mitigate organic pollutants in water. However, poor activity under visible light and the recombination of photogenerated electron and hole pairs hinder large scale applicability of semiconductor photocatalysts for water purification. The modification of semiconductor photocatalysts with carbon quantum dots (CQDs) is of high importance due to low toxicity, aqueous stability, enhanced surface area, economic feasibility, good biocompatibility and chemical inertness of CQDs. In this review, we highlight strategies to improve the activity of conventional semiconductor photocatalysts via coupling with CQDs. The enhanced photocatalytic activity of CQD modified narrow and wide band gap photocatalysts is due mainly to up-conversion photoluminescence (UPCL) and the electron reservoir properties of CQDs, while in the case of Z-scheme photocatalysts CQDs act as an electron mediator. Finally, a conclusive outlook and suggested research directions are provided to address challenges such as the inadequate separation of photoinduced charge carriers

Synthesis of Eu3+−doped ZnO/Bi2O3 heterojunction photocatalyst on graphene oxide sheets for visible light-assisted degradation of 2,4-dimethyl phenol and bacteria killing

We reported the immobilization of binary heterojunction Eu3+-ZnO/Bi2O3 over the surface of graphene oxide (GO) sheets by precipitation method to compose a visible light drive photocatalyst. The ternary nanocomposites were characterized by different spectral technique like FESEM, FTIR, XRD, XPS, EDX, HRTEM, UV–visible, PL, HPLC and LCMS analysis. The high specific surface area of 106.0 m2g-1 of Eu3+-ZnO/Bi2O3/GO nanocomposites was ascertained by BET adsorption-desorption isotherm. The nano-composite exhibit excellent photo-efficiency for the photodegradation of 2, 4-dimethyl phenol (DMP) under visible region and was almost completely mineralized in 100 min as compared to the bare and binary system. The mineralized products of DMP were analyzed by HPLC and LCMS analysis. The kinetic model suggests the degradation pathway obeys pseudo-first order kinetic. Their antibacterial property were assessed against E. coli bacteria and nearly 90% of gram negative bacteria were killed by using ternary photocatalyst as determined by CFU method. Also, Eu3+-ZnO/Bi2O3/GO nanocomposites possessed significant recycle efficiency up to six consecutive cycles which is beneficial to minimize the tariff. The improved photo-efficiency is due to the extension towards visible region, increase surface area, and high charge separation in ternary heterojunction

Optimization of Subsurface Artificial Wetlands with Pine Tree Fruit (pine cones) as a Bed Filler for Municipal Wastewater Treatment

Background and Aims: Constructed wetlands are noticeably cost-effective in terms of energy consumption, operation and maintenance. Many researches have been done on the efficiency of wetlands removal in wastewater treatment but the information is limited on media used in these beds and its impact on treatment  efficiency. This study aimed to optimize subsurface artificial wetlands with pine tree fruit as a bed filler for municipal wastewater treatment. Materials and Methods: In this study sample and control pilots were made out of bricks and cement in dimensions of 2*1*0.8 meters.Used municipal wastewater passed through a primary sedimentation tank with a detention time of 3 hours and entered the pilot with flow rate of 0.85 liters per hour. Hydraulic detention time of beds was 8 days. Chemical parameters TN, TP, COD and TSS were evaluated by standard methods. Sampling were commited twice a week, each time in compound way and a time span of 4 hours. Results were extracted based on data average floating. Results: According to data obtained from pilot performance the removal efficiency of TN, TP, TSS, COD, in the control bed were 79.68, 88.31, 85.3, 83.03 percent, and in the sample bed were 91.45, 92.88, 88.86, 86.6 percent respectively. Conclusion: The reason behind increased removal efficiency of using fruit trees can be the high level of area, especially high porous space and biofilm increase and consequently efficiency increase of organic carbon, Nitrogen and suspended solids