The current study was intended to synthesize and characterize the physical, chemical, and mechanical properties of carbon/ carbon (C/C) composites using the chemical vapor infiltration (CVI) process. To that end, carbon fiber felt (CF) was used as a preform, and methane and hydrogen were employed as reactive and carrier gases, respectively. After deciding on the optimum temperature (1050 °C), the composite samples were produced at different times (0–195 h). Then the samples were studied for their phase and microstructure characteristics using XRD, SEM, FESEM, FTIR, and Raman spectroscope. The results showed that by increasing the CVI process time up to 195 h, the density of the produced samples increased from 0.20 to 1.62 g/cm3, and the specific surface area decreased from 58.78 to 0.23 m2/ g. Also, by increasing the process duration, the deposition rate decreased due to the reduction of the available surface for carbon deposition. In other words, due to the increase in density, and decrease in both porosity and specific surface area, the thermal conductivity coefficient and the bending strength of the samples increased. The composite specimens’ SEM images of the fracture surface indicated a weak interface between the carbon fibers and the carbon layer developed by the CVI process. The structural analyses showed that the morphology of carbon growth during the CVI process was initially laminar, but changed to rough-laminar (RL) with the higher duration of the CVI process.

In this study, Fe3O4/ MgO/Activated carbon composite was used to remove arsenic ion (As (III)) from aqueous media. To this end, Frangula Alnus was used to prepare activated carbon (AC) by calcination in the furnace at 700 °C for 4 h and was then used to synthesize the MgO/Fe3O4/AC composite. To study the surface properties of the composite, various analyses such as SEM, EDX/Mapping, FTIR, DLS, BET and VSM were applied. According to the BET analysis, the specific surface area and average pore size of the Fe3O4/ MgO/AC composite were obtained as 190.92 m2/g and 7.57 nm, respectively, which showed that the aforementioned nanocomposite had a mesoporos structure with an excellent specific surface area. Also, VSM analysis indicated that the composite had a superparamagnetic property and could be easily separated from the solution by a magnet. Moreover, the results of the As (III) sorption indicated that the highest uptake efficiency was obtained 96.65% at pH = 7, adsorbent dosage = 0.13 g/L, t = 35 min, T = 45 °C and Co = 6 mg/L. In addition, the pseudo-second-order model could better describe the kinetic behavior of the sorption process. Furthermore, Langmuir model was the best model to describe the equilibroium behavior of the As(III) ion sorption. Besides, according to the the thermodynamic study, enthalpy change and entropy change were obtained 58.11 kJ/mol and 224.49 J/mol.K, respectively, indicating that the sorption process was spontaneous and endothermic. According to the results, the Fe3O4/ MgO/AC composite was a good adsorbent with the extraordinary properties, which can be used on an industrial scale.

A novel approach was presented for deposition of nickel–graphene nanocomposite coating on copper. Unlike conventional methods, graphene and graphene oxide nanosheets were not used. The basis of the method is to synthesize graphene oxide by oxidation of graphite anode during the electrochemical deposition process. The obtained graphene oxide sheets were reduced during the deposition in the cathode and co-formed with the nickel deposition in the coating. The pulsed ultrasonic force was applied during the deposition process. When the ultrasonic force stops, the deposition process begins. Scanning electron microscopy, Raman spectroscopy, atomic force microscopy, X-ray diffraction and X-ray photoelectron spectroscopy confirmed the presence of graphene nanosheets in the coating. The amount of graphene nanosheets increases up to a maximum of 14.8 wt% by increasing the time of applying ultrasonic force to 6 s. In addition, with the presence of graphene in the nickel coating, the wear rate dramatically decreased.

In the present work, the influence of the ball-milling time, milling atmosphere and weight ratio of ball to powder on characteristics of was studied. Results show that, the grain sizes of the and CuO in the ball-milled powder mixture were significantly decreased with increasing the milling time. Those of each oxide ball-milled in Argon and Hexane atmosphere for 30 and 20 hour were about 98 and 84 nm, respectively. After milling of 20 hour in Hexane as PCA, the powder had a homogeneously mixed structure and the average size of powders was determined to about 230nm.

Purpose - objective of this research is to investigate individual, organizational and environmental factors influence tacit knowledge sharing among healthcare professionals. The transmission of Tacit Knowledge is crucial for organizations to ensure that TK will be passed throughout organization, rather than stored in single employee. Research design, data, and methodology - In this study investigate organizational, individual and environmental factors that influence on TK sharing. To test hypothesizes, the survey method was chosen. Sample size was 100 but 74% of questioners returned. Results - The main findings of this research are related to influence of personal, social cultural and behavioral factors on tacit knowledge sharing. According to extracted data all factors have influence on tacit knowledge sharing except Emotional stability that was found to be negatively related to tacit knowledge sharing. That may means anxiety and stress level of workplace applies negative enhance on tacit knowledge sharing. And finally results show that social environment, team oriented culture and organizational commitment have strongest influences on tacit knowledge sharing. Conclusion - the findings of this study shows that personal, social cultural and behavioral factors influence on tacit knowledge sharing. And also indicates that, social and organizational factors enhance strongly on tacit knowledge sharing.