Hypothesis: Dehumidification of a gas stream was carried out by one of the newest separation techniques. Different processes have been proposed for gas humidification such as absorption process using an absorbent and adsorption process with higher capital and operating costs than the former. The former process is more common. Methods: For humidification/dehumidification process two hollow fiber membrane contactor modules were made using Polyetherimide hollow fiber membranes. At first, the dry inlet gas was humidified in the first contactor module and then, the dehumidification process was performed by the second module. In dehumidification process, monoethylene glycol (as the absorbent) was allowed to flow through the shell side of the contactor while the wet gas flowed through the fibers. The different operating parameters such as the pressure and flow rate of the wet gas were studied in relation to the performance of dehumidification system. Findings: The results showed that by increasing the wet gas flow rate from 1 SLPM (standard liter per minute) to 3 SLPM, the water vapor absorption flux increased by 133%, indicating that the effect of decrease in gas phase mass transfer resistance in dehumidification process overcomes the effect of reduction in humidity content of the inlet gas to the dehumidification system. Furthermore, by increasing the gas pressure from 1 bar to 5 bar, the water vapor absorption flux decreased by 55% which showed that drop in humidity content of the inlet gas to dehumidification system (due to the pressure enhancement) affects the water vapor absorption process. Therefore, the operating conditions of the dehumidification process should be selected based on the effective parameters.

This research focused on improving the antifouling properties and rejection performance of Polyetherimide (PEI) nanofiltration membrane by chemical surface modification (surface coating). The hydrophilicity of the PEI nanofiltration membrane’, s surface was enhanced by anchoring guanidine on its surface which the used dosage of guanidine was considered as a variable (0. 5, 1, and 1. 5 g/L of guanidine concentration). ATR-FTIR, SEM, AFM, and water contact angle were used to characterize the surface-modified membranes. Also, dry milk powder solution was considered as an organic foulant to assess antifouling features of the fabricated membranes. According to the obtained results, the surfacemodified membrane with 0. 5 g/L of guanidine concentration was the optimal surface-modified membrane with pure water flux (PWF) and flux recovery ratio (FRR) of 11. 6 kg/m2. h and 88. 8%, respectively. Moreover, the capabilities of the optimal surface-modified membrane and the pristine membrane for rejecting AS5+ and Hg2+ in aqueous solution with concentrations of 20 ppm and 50 mg/L were compared. Based on the obtained results, the optimal surface-modified membrane rejected more than 98. 5 % of AS5+ and Hg2+ solutions with 20 and 50 mg/L of metal ion concentrations.

In hollow fiber membrane fabrication process, a number of parameters such as dope compositions, flow rate, bore fluid type, flow rate, and air gap affect the structure and characteristics of membrane. Spinneret dimension as the effective parameter on the properties of a Polyetherimide (PEI) hollow fiber membrane and its performance in membrane contactor was examined. A polymer solution was used for fabrication of two PEI membranes under the same fabrication conditions, with variable-spinneret dimensions. Through the addition of water as a non-solvent into the polymer solution, the thermodynamic stability of the solution decreased and the phase-inversion process increased, and therefore, the effects of chain reorientation or chain relaxation on the structure of hollow fiber membrane were minimized. The fabricated membranes were characterized by different tests and their performance in membrane contractor and in CO2 absorption test was evaluated in two events: 1-distilled water in lumen side and pure CO2 in shell side and 2-distilled water in shell side and pure CO2 in lumen side. The results showed that smaller dimension of spinneret enhanced the properties of membrane such as 250% increase in mean pore size and 300% increase in gas permeation rate. In addition, the smaller dimension of the spinneret formed more pores in the structure of membrane that could be related to the shorter diffusion distance of the coagulant. Furthermore, the CO2 absorption flux improved by 150%.

This study investigated the efficiency of membrane polyetheretherketone/Polyetherimide modified with magnesium oxide nanoparticles to remove xylene and toluene from the air with gas chromatography. The influence of effective parameters such as sorbent dosage, extraction time, and extraction temperature of the sample was investigated and the optimum conditions were chosen. Various techniques including FT-IR, XRD, EDX, and SEM, were used to characterize this membrane. To optimize adsorption efficiency, factors such as xylene and toluene concentration, adsorbent dosage, temperature, and contact time were carefully fine-tuned. It was found that 50 mg of membranes has the best adsorption efficiency for both pollutants. The maximum adsorption capacities were found to be 163 mg/g for xylene and 200 mg/g for toluene on the PEEK/PEI nanocomposite adsorbent. Moreover, 190 mg/g for xylene and 230 mg/g for toluene were observed on the PEEK/PEI membrane modified with MgO nanoparticles. These results clearly demonstrate that PEEK/PEI membrane modified with MgO nanoparticles is a highly efficient adsorbent for eliminating xylene and toluene from air, making it a promising solution for air quality purification and environmental remediation applications.    

Failures in composite materials occur mainly due to interlaminar fracture, also called delamination, between laminates. This indicates that characterizing interlaminar fracture toughness is the most effective factor in the fracture of composite materials. This study reports investigation on mixed-mode interlaminar fracture behaviour in woven carbon fibre/Polyetherimide (CF/FEI) thermoplastic composite material based on experimental and numerical analyses.Experiments were conducted using the special test loading device. By varying the loading angle,α from 0º to 90º, pure mode-I, pure mode-II and a wide range of mixed-mode data were obtained experimentally. Using the finite-element results, geometrical factors were applied to the specimen. Based on experimentally measured critical loads, mixed-mode interlaminar fracture toughness for the composite under consideration determined. The fracture surfaces were examined by scanning electron microscopy to gain insight into the failure responses.

In the process of molding parts using the plastic injection molding method, it is key essential to apply appropriate parameters in order to produce a qualified product. The purpose of this paper is to choose helpful production parameters and optimize them for molding eight different parts made from Polyetherimide. In the beginning, based on the previous research and the capabilities of Mold Flow software, appropriate process parameters were chosen. These parameters were: melt temperature, mold surface temperature, packing pressure and coolant inlet temperature. The simulations in Mold Flow software were done based on Taguchi’s L25 orthogonal array. Afterward, the critical and comparable results including: volumetric shrinkage, sink mark, warpage and the percentage of frozen volume in parts were exported from the simulations. Eventually, the optimizations were made based on these results by applying the gray relational analysis. The optimizing results show that in all distinguishing coefficients of the gray relational analysis (0.1 to 0.9), the melt temperature was 360 °c, the mold surface temperature was 140 °c, the packing pressure was 100% of the injection pressure and the coolant inlet temperature was 12.5 °c lower than the mold surface temperature of the most optimized ones. Also based on the ANOVA results, in all difference indices, parameters of melt temperature and packing pressure were respectively the most effective.

It is necessary to recover dimethyl sulfoxide (DMSO) from pharmaceutical organic wastewater. In recent years, organic solvent nanofiltration (OSN), as an important means of recovering organic solvents, is being studied and paid attention constantly. Here, we prepared a solvent-resistant composite nanofiltration membrane with stable performance for the recovery of DMSO solvent using orcinol (OL), a natural alkyl resorcinol compound to synthetize a thin-film composite polyarylester membrane with trimesoyl chloride (TMC) by interfacial polymerization (IP) on the Polyetherimide (PEI) substrate crosslinked by ethylenediamine (EDA). The results of chemical characterization such as X-ray photoelectron spectroscopy (XPS) and attenuated total reflection fluorescence transform infrared spectroscopy (ATR-FTIR) show that interfacial polymerization occurs between TMC and orcinol on the surface of PEI and forms polyarylester top-layer. The rejection of crystal violet (CV, 407. 99 g/mol) in DMSO takes place by 91%, and the maximum permeance is about 3. 1 L. m−, 2. h−, 1. bar−, 1. To further improve selectivity of membrane, microwave heating was adopted as a strengthening method of interfacial polymerization. The results illustrate that the microwave heating can significantly increase the rejection of OL-TMC membrane. The optimized membrane shows stable solvent resistance in DMSO with a rejection of 98% for CV and the permeance of 1. 8 L. m−, 2. h−, 1. bar−, 1 and a rejection of 81% for clindamycin phosphate (CLP) with the permeance of 1. 9 L. m−, 2. h−, 1. bar−, 1. This study not only opens up an interesting research field for more natural polyphenols as solvent-resistant nanofiltration membrane materials, but also indicates that microwave-assisted heating can be used as an important means during IP process to strengthen the properties of OSN membranes.

In the present work, development models of a new artificial human soft heart and artificial heart valves using nanocomposite materials and synthetics were designed, manufactured, and tested. The fabricated mechanical artificial heart valves were examined to determine the best service life for each type. The fatigue life results were implemented by using the transient repeated and continuously applied blood pressure on each produced value to simulate diastolic and systolic that occur in the natural heart at each pulse cycle. The obtained results showed that a 3D printing of a new generation soft artificial heart for a permanent replacement was implemented as an alternative to the high-cost available temporary implant mechanical hearts, which may exceed the price by tens and hundreds of thousands of dollars, with a working life of not more than five years. The obtained fatigue safety factors for the produced artificial valves using different materials and designs were decreased with the complexity of the movement of the moving parts of the valve. The highest rates were obtained when using the valves with flat, simple movement in one direction like the single-leaflet type valve, where all the used materials are suitable for the production of this type of valve. The highest obtained safety factor was reached (15). The lowest rates were recorded when using the highly flexible and strong PSN4 nanocomposite material for fabricating the mitral tri-leaflet valve (thick. = 1.0 mm) reached 1.91. This value decreases to 0.99 when using the same type and material of valve but with a thickness equal to 0.5 mm. It can be noted here that the only suitable for the manufacture of this artificial valve type is the nanocomposite Polyetherimide/ silicone rubber with nano silica (PSN4), whereas the other used materials failed because the fatigue factor values are less than 1. The service life span of this material is about 9200 x 106 cycles, which is equivalent to about 290 years, followed by SIBSTAR 103 with a default age of 209.6 x 106 cycles or 9 years.