The electrospun nanofibers membranes (ENMs) have gained great attention due to their superior performance. However, the low mechanical strength of ENMs, such as the rigidity and low strength, limits their applications in many aspects which need adequate strength, such as water filtration. This work investigates the impact of electrospinning parameters on the properties of ENMs fabricated from polyacrylonitrile (PAN) solved in N, N-Dimethylformamide (DMF). The studied electrospinning parameters were polymer concentration, solution flow rate, collector rotating speed, and the distance between the needle and collector. The fabricated ENMs were characterized using scanning electron microscopy (SEM) to understand the surface morphology and estimate the average fiber sizes. The membrane porosity percentage was measured using the dry-wet weight method. Also, a dynamic mechanical analyzer was used to determine the mechanical strength properties (tensile strength and Young's modulus) (DMA). The obtained results revealed that the polymer concentration and flow rate mainly affect the porosity and fiber size in ENMs. Increasing the polymer concentration improves the strength and flexibility, while the flow rate did not show a clear effect on the mechanical strength of ENMs. Both fibers collecting speed and spinning distance did not clearly impact the membrane morphology. ENMs flexibility significantly increased with increasing the collector speed and decreasing the spinning distance. Strong and flexible ENMs with small fibers can be fabricated using 10% PAN/DMF at a flow rate of 1 mL/h, collector speed of 140 rpm, and spinning distance of 13 cm.
Recommender Systems are tools to understand the huge amount of data available in the internet world. Collaborative filtering (CF) is one of the most knowledge discovery methods used positively in recommendation system. Memory collaborative filtering emphasizes on using facts about present users to predict new things for the target user. Similarity measures are the core operations in collaborative filtering and the prediction accuracy is mostly dependent on similarity calculations. In this study, a combination of weighted parameters and traditional similarity measures are conducted to calculate relationship among users over Movie Lens data set rating matrix. The advantages and disadvantages of each measure are spotted. From the study, a n
... Show MoreThe importance of internal audit in the growing demand for services in the public and private economic units, and in the rapid growth of its systems professional, has also been recognition of the importance of internal audit quality and the quality of information provided in a long time, as well as the importance of achieving the greatest possible quality in his work to reduce accounting risks of financial reports misleading or fraudulent, which is one of the important features of the audit.
The internal audit quality are linked with the ability of auditors to detect errors in the financial statements, and their willingness to express an opinion technical neutral and non-aligned based on the results of th
... Show MoreSynthetic polymers such as polyurethane are used widely in the field of biomedical applications such as implants or part of implant systems.
This paper focuses on the preparation of base polymer matrix composite materials by (Hand Lay-Up) method, and studying the effect of selected grain size (32, 53, 63, 75, and 90) µm of (Reenia) particles on some properties of the prepared composite.
Mechanical tests were used to evaluate the prepared system (Tensile, Compression, Impact, and Hardness) tests, and a physical test of (Water absorption %), and all tests were accomplished at room temperature.
Where results showed tensile test (maximum tensile strength and modulus of elasticity) high at small grain size while
... Show MoreTo evaluate impact the difference in stages ofage and related incidence of hemodialysis patients.Two hundred and fifty patients undergoing hemodialysis were collected from general hospital in Baghdad city /Iraq. The samples with renal failure before hemodialysis were divided into (138) male,( 112)female. The sera were separated from samples to physiological investigation. We found that renal failure was more predominant among the patients ages group ranging from (51-70) years old. The results shows A significant increase in the levels of urea, creatinine, in younger patients (≤ 30 years) when compared with older patients (>70 years). Furthermore a significant decrease in serum levels of total protein in patients in older patients (>7
... Show MoreSlurry-infiltrated fibrous concrete (SIFCON) is a special type of concrete that has great strength, as well as high ductility. However, the unit weight is high, which exceeds the unit weight of fiber-reinforced concrete, because of the high fiber content. This research aims to verify the compressive and flexural strength, as well as the density of SIFCON when using two different fibers (steel and polyolefin). Sometimes mono type of fiber steel or polyolefin, sometimes by hybridizing two types of fiber steel + polyplefin. Volume fraction (6% for all species) was used. Hook-end steel fiber and polyolefin fiber are used. With hybridization, a total volume fraction of 6% was used, which
Using photo electrochemical etching technique (PEC), porous silicon (PS) layers were produced on n-type silicon (Si) wafers to generate porous silicon for n-type with an orientation of (111) The results of etching time were investigated at: (5,10,15 min). X-ray diffraction experiments revealed differences between the surface of the sample sheet and the synthesized porous silicon. The largest crystal size is (30 nm) and the lowest crystal size is (28.6 nm) The analysis of Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM) were used to research the morphology of porous silicon layer. As etching time increased, AFM findings showed that root mean square (RMS) of roughness and po
... Show MoreThis study exposed to use the liquid whey (which was produced from of soft cheese processed) partially or completely instead of milk in fatty cake, this whey residue is still not used, instead it is thrown in rivers which effect different environment and economic problems. Different concentrations was used (25% , 50% , 75% , and 100%) of whey in baked cake , Volume , height and other different properties ( panel taste ) was studied too . Sensory evaluation results showed that an improved in all the character of the baked cake was happen by the used of 25% and 50% of the whey in comparison with the control treatment, the 75% replacement showed a decrease in appearance , texture and tenderness , while the degrees of color and fla
... Show MoreABSTRACT
A laboratory experiment was carried out during winter season of 2021 in the Seed Technology Laboratory- College of Agricultural Engineering Sciences/ University of Baghdad, to find out the allopathic effects of aerobic and terrestrial aqueous extracts of Artemisia vulgaris L. on the seed germination and seedling growth of linseed. A factorial experiment according to a completely randomized design (CRD)at three replicates was used; the first factor in clouded type of aqueous extract for two plant parts which were aerobic (stems and leaves) and terrestrial (root and rhizomes), while the second factor included five concentrations
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