Materials Science
Faisal J. Kadhim; Mohamed Hedi Bedoui; Ali A. Turki Aldalawi
Abstract
In this study, Fe₂O₃ nanoparticles were synthesized by a hydrothermal method using chitosan extract and ferric chloride (FeCl₃) as precursor at 150 °C. The hydrothermal approach provides precise control over the size and morphology of the nanoparticles by promoting the decomposition and crystallization ...
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In this study, Fe₂O₃ nanoparticles were synthesized by a hydrothermal method using chitosan extract and ferric chloride (FeCl₃) as precursor at 150 °C. The hydrothermal approach provides precise control over the size and morphology of the nanoparticles by promoting the decomposition and crystallization of the precursors near their evaporation temperatures. The aim of this study was to quantify the antibacterial activity of the nanoparticles to regulate the production of Fe₂O₃ NPs. The optical and structural properties of Fe₂O₃ nanoparticles (NPs) were investigated and tested using various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL). The crystal size and hexagonal structure of Fe₂O₃ NPs in the range of 10 to 25 nm were determined by XRD. In addition, FESEM images were used for measurement. The morphology and particle size of the Fe₂O₃ NPs, which is between 15.63 and 56.84 nm due to the aggregation of the nanoparticles. The UV-visible spectra were used to calculate the direct and indirect optical band gap versus hν of the Fe₂O₃ NPs prepared by the hydrothermal method from chitosan extract NPs. These are 3.8 eV and 3.6 eV, respectively. The band edge emission of Fe₂O₃ NPs was about 2.57 eV as measured by photoluminescence (PL) spectroscopy. Inhibition zones of 40 mm in size were observed for Staphylococcus aureus and Escherichia coli.
Materials Science
Rana Mahdi Salih; Shanaz Husein Ahmad
Abstract
The current work focuses on assessing flexural properties, and water uptake of polymeric composites prepared using various reinforcements. These additives consist of kaolinite nano clays and rock wool (RW). In addition to a polymer blend that consists of epoxy and polyester resins as the matrix. The ...
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The current work focuses on assessing flexural properties, and water uptake of polymeric composites prepared using various reinforcements. These additives consist of kaolinite nano clays and rock wool (RW). In addition to a polymer blend that consists of epoxy and polyester resins as the matrix. The castings were made using a hand lay-up approach. Nanoclay (NC) was added in weight fractions of 5% and 7%, together with RW added in a volume fraction of 10% as reinforcement. The impact test was employed to decide the optimum mixing ratio of the polymer blend that used as a matrix. From the results the blend consisting of 80 wt.% epoxy and 20 wt.% polyester has the highest impact strength value. Thermal analysis was done using differential scanning calorimetry (DSC) as a characterization method to assess the miscibility of the polymer blend. The polyester/epoxy blend showed the maximum flexural strength, which determined as (57.4) MPa. While the hybrid reinforcement using NC (5 wt.%) and RW (10%) lowered the flexural strength to 16.53 MPa. From the water absorption test results showed that, in addition to the standard concentration, the type of material also affects water, in addition to the ratios of its components. Finally, DSC results revealed the presence of two different glass transition temperatures, which indicates that the epoxy/polyester blend is immiscible and there are two distinct phases in this matrix.
Materials Science
Aymen F. Zween; Zaidoon M. Shakor; Bashir Y. Sherhan
Abstract
Recycling residue hydrodesulfurization (HDS) catalysts is essential due to frequent deactivation. Petroleum coke's high ignition temperature and complex combustion behavior stem from its graphite-like structure and low volatile matter. This study investigates petroleum coke combustion and oxidation kinetics ...
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Recycling residue hydrodesulfurization (HDS) catalysts is essential due to frequent deactivation. Petroleum coke's high ignition temperature and complex combustion behavior stem from its graphite-like structure and low volatile matter. This study investigates petroleum coke combustion and oxidation kinetics with metal catalysts. Data from HDS catalysts (5% Co-10% Mo/active kaolin and 5% Co-10% Mo/active bentonite) are crucial for industrial regenerator simulations. Iraqi mineral clays, treated and loaded with cobalt and molybdenum, were used in HDS reactions of Iraqi gas oil with 10200 ppm sulfur at 360°C, 12 bar, and WHSV of 2 h⁻¹. Spent catalysts, coated with coke, were analyzed, and coke was removed using thermogravimetric analysis (TGA) at heating rates of 2.5, 5, and 10°C/min. MATLAB software assessed coke accumulation's impact on combustion activation energy via model-free and model-based methods. Activation energies for coke combustion were 46.48, 87.71, and 102.68 kJ/mol for hydrocarbons, soft coke, and hard coke, respectively, on 5% Co-10% Mo/active kaolin, and 41.98, 68.11, and 100.38 kJ/mol for 5% Co-10% Mo/active bentonite. TGA revealed 7.553% and 7.977% total weight loss in kaolin and bentonite catalysts. The model-based method was most effective for regenerating aged HDS catalysts at 850°C, especially for hard coke removal. DTG analysis showed two concavities, indicating soft coke below 350°C and hard coke between 350 and 850°C. For 5%Co-10%Mo/kaolin catalysts, peak temperatures (Tpeak) were 517, 526, and 610°C at heating rates of 2.5, 5, and 10°C/min. Bentonite catalysts showed lower Tpeak values.
Materials Science
Safa Luay Jasim; Shihab A. Zaidan; Enas Muhi Hadi
Abstract
Refractory ceramics were produced using silicon carbide (SiC) as the main component in combination with different weight percentages of Iraqi white kaolin (20%, 40%, 60% and 80%). Two different weight percentages of alumina (5% and 10%) were then added to each SiC-kaolin mixture. The samples were effectively ...
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Refractory ceramics were produced using silicon carbide (SiC) as the main component in combination with different weight percentages of Iraqi white kaolin (20%, 40%, 60% and 80%). Two different weight percentages of alumina (5% and 10%) were then added to each SiC-kaolin mixture. The samples were effectively mixed, molded, dried and fired at 1300 °C. The structural and physical properties were measured, including X-ray diffraction, apparent porosity, water absorption and thermal conductivity. X-ray diffraction showed that the addition of Al2O3 to the SiC-kaolin composite increased the mullite phase by interacting with the excess silica formed during the firing of kaolin or with the silica formed during the oxidation of SiC. The increase in kaolin content in the composite without alumina was accompanied by a decrease in physical properties, as the apparent porosity decreased from 30.17% to 17.95% and the water absorption from 16.31% to 7.07%. The addition of 80 wt.% kaolin led to a decrease in thermal conductivity from 35 to 15 W/m.K. The addition of 10 wt% Al2O3 also reduced the apparent porosity and water absorption to 13.85% and 5.33% respectively for the (SiC-20 wt% kaolin) sample. The apparent porosity and water absorption of the sample (SiC-80 wt% kaolin) with 10 wt% Al2O3 reached the lowest values of 9.44% and 3.55%, respectively. The thermal conductivity decreased from 15 to 12 W/m.K. This study found that adding alumina improves refractory efficiency due to its high melting point, making it ideal for high-temperature applications.
Materials Science
Shanaz H. Ahmed; Awham M. Hameed; Khalida F. Al-Azawi
Abstract
The brittleness and porosity of cement mortar leads to low compressive, flexural, and tensile strengths and poor hardness, making it susceptible to environmental degradation. This study aimed to improve the mechanical and physical properties of cement mortar using a simple and cost-effective approach ...
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The brittleness and porosity of cement mortar leads to low compressive, flexural, and tensile strengths and poor hardness, making it susceptible to environmental degradation. This study aimed to improve the mechanical and physical properties of cement mortar using a simple and cost-effective approach of impregnating pre-cured hardened mortar with polymers. Three polymers - polyethylene glycol (PEG), polyacrylamide (PAM), and polyvinyl alcohol (PVA) - were used for impregnation. The polymers were blended with a magnetic stirrer and the impregnation was performed via three methods: vacuum, ultrasound, and 24-hour immersion. The results showed significant improvements in mechanical and physical properties. PEG-impregnated samples exhibited the highest compressive strength (24.47 MPa), flexural strength (1.38 MPa), and splitting tensile strength (2.08 MPa) compared to reference samples with 17 MPa, 0.52 MPa, and 1.35 MPa respectively. PAM-impregnated cement mortar displayed the highest hardness value of 81 versus 70.08 for the reference sample. Optimal results were achieved via the vacuum method, with increases in bulk density. The polymer impregnation filled pores and improved bonding, enhancing the mechanical properties of the brittle cement mortar.
Materials Science
Shatha Sh. Batros; Mohammed H. Ali; Ali J. Addie
Abstract
Tin oxide (SnO2) nanoparticles were synthesized via a facile chemical precipitation route using tin chloride (SnCl2•2H2O) as precursor and ammonia as precipitant. The as-synthesized nanoparticles were subjected to post-calcination at 300°C, 400°C and 500°C and thoroughly characterized ...
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Tin oxide (SnO2) nanoparticles were synthesized via a facile chemical precipitation route using tin chloride (SnCl2•2H2O) as precursor and ammonia as precipitant. The as-synthesized nanoparticles were subjected to post-calcination at 300°C, 400°C and 500°C and thoroughly characterized by advanced techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy. XRD patterns revealed the formation of a tetragonal SnO2 crystalline phase with average crystallite sizes of 11.9 nm, 13.9 nm, and 17.2 nm for the samples calcined at 300°C, 400°C and 500°C respectively. SEM micrographs demonstrated agglomerated and irregular morphology of the calcined SnO2 nanoparticles. FTIR spectra confirmed the presence of characteristic Sn-O and O-Sn-O vibrational modes in the calcined SnO2 samples. The antibacterial activity of the synthesized nanoparticles was evaluated against model Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial strains by standard zone of inhibition assays. The SnO2 nanoparticles exhibited excellent antibacterial activity due to their high specific surface area. A systematic increase in the inhibition zone diameter was observed with a decrease in the crystallite size of SnO2 for both bacterial strains, suggesting an inverse relationship between crystallite size and antibacterial behaviour. The present work demonstrates a simple, eco-friendly synthesis of antibacterial SnO2 nanoparticles with controlled crystallite size by tuning the calcination temperature.
Materials Science
Narcisse B. Basosila; Clément L. Inkoto; Ormiel M. Maganga; Blaise Mbembo; Giresse N. Kasiama; Carlos Kabengele; Clarisse M. Falanga; Colette A. Masengo; Pius T. Mpiana; Koto-Te-Nyiwa Ngbolua
Abstract
The use of plant extracts as a bio-reducer for the synthesis of silver nanoparticles has attracted attention due to its rapid, ecological, non-toxic and economical protocol. The aim of this study was to investigate the possibility of synthesizing silver nanoparticles using Cymbopogon citratus leaf extract, ...
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The use of plant extracts as a bio-reducer for the synthesis of silver nanoparticles has attracted attention due to its rapid, ecological, non-toxic and economical protocol. The aim of this study was to investigate the possibility of synthesizing silver nanoparticles using Cymbopogon citratus leaf extract, and characterizing them by Ultraviolet-visible spectroscopy, X-ray Diffraction and X-ray Fluorescence in order to determine their size and composition, as well as to evaluate them in-vitro bioactivity on selected models. The results of this study show that silver nanoparticles were successfully synthesized, with a size of 29.49 nm. The silver nanoparticles showed bactericidal activity against all three types of bacteria (E. coli ATCC 25922, S. aureus ATCC 25923, and P. aerugunosa ATCC 27853) at the minimum inhibitory concentration (MIC=31.25 μg/mL), larvicidal activity against Anopheles larvae and reasonable antioxidant properties. All these results demonstrate the biopharmaceutical potential of these new products. These nanoparticles, synthesized from plant extracts, could be a promising solution for the treatment of a number of diseases, including malaria, bacterial infections and diseases caused by oxidative stress.
Materials Science
Peverga Rex Jubu; Khaled M. Chahrour; Yushamdan Yusof; A. Nathan-Abutu; V. M. Igba; E. Danladi; O. S. Obaseki; M. B. Ochang; W. V. Zhiya; F. K. Yam
Abstract
The presence of multiple phases/ components within a nanocomposite material impacts its properties. Therefore, there is a need to estimate the phase fraction of each element present in a sample. Spurr-Myers proposed a valuable formula for calculating the rutile and anatase phase fraction of a TiO2 sample ...
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The presence of multiple phases/ components within a nanocomposite material impacts its properties. Therefore, there is a need to estimate the phase fraction of each element present in a sample. Spurr-Myers proposed a valuable formula for calculating the rutile and anatase phase fraction of a TiO2 sample from X-ray diffraction. However, this formula is dedicated to TiO2 and is inapplicable to samples that contain more than two phases. The present research proposed a simple method for quantifying the phase fraction of all types of nanomaterials consisting of two or more phases. The precision/ accuracy test, conducted by multiplying the total intensity of all the diffraction peaks present in a sample with the value of the phase fraction of individual components, showed that the proposed method gave precision values equivalent to the sum of the intensity of the peaks for each element. Meanwhile, the S-M gave precision values that were significantly inconsistent with the sum of the intensity of the peaks of each component. The study showed that the proposed method was valid for a wide range of 2θ values and can be deployed to obtain reasonable and reliable values of phase fraction that could assist in understanding the material phase fraction-properties relationship.
Materials Science
Ruaa Khalid Hamdan; Aqeel Al-Adili; Thamer Ahmed Mohammed
Abstract
This study presents an experimental measurements and three-dimensional simulation of time-varying scour, along with the variables affecting the resulted scour hole dimensions and evolution at center and side weirs. Slit weir location, crest level, flow rate and sediment size were tested within 34 steady ...
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This study presents an experimental measurements and three-dimensional simulation of time-varying scour, along with the variables affecting the resulted scour hole dimensions and evolution at center and side weirs. Slit weir location, crest level, flow rate and sediment size were tested within 34 steady and unsteady flow conditions under various flow rates 125, 95, 62, 50 and 34 L/s to study the scour behavior. All tests were carried out with non-uniform sediments of median sizes 0.24 mm and 0.55 mm. Steel slit weirs of 0.25 m width, 0.004 m thickness, and 0.07, 0.12 and 0.17 m crest level with respect to the mobile bed surface, which was constructed in a laboratory flume made up of brick and concrete within dimensions of (8 m, 1.25 m, and 1 m) long, wide and deep respectively. The present research demonstrates that maximum values of scour volume and scour depth obtained when the weir locate at center of the flume with flat crest for both steady and unsteady flow. Besides, the results indicated a low discrepancy between the experimental measures and the sediment scour model FLOW 3D software, both are showed a good agreement in presenting the scour development accurately as well as the model had excellent ability in predicting the velocity magnitudes at the slit location and the values of shear stress which was hard to measure directly.
Materials Science
Sanjeev Singh; Arti Singh; Pavagada Shaifulla
Abstract
The aim of this study was to compare whether the Bispectral Index (BIS) reduces anaesthesia consumption and improves recovery time in coronary artery bypass grafting-off-pump (CABG) surgery without awareness during surgery (ADS). The study was a prospective, randomised and double-blind comparative study ...
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The aim of this study was to compare whether the Bispectral Index (BIS) reduces anaesthesia consumption and improves recovery time in coronary artery bypass grafting-off-pump (CABG) surgery without awareness during surgery (ADS). The study was a prospective, randomised and double-blind comparative study of ASA3 patients enrolled for elective CABG surgery under general anaesthesia (GA). Patients received either propofol or isoflurane anaesthesia and their consumption was calculated and compared. Conventional groups CPG-1 and CIG-3 received propofol and isoflurane, and haemodynamic parameters (± 20% of baseline values) were considered for anaesthesia. Groups BPG-2 and BIG-4 received propofol and isoflurane, and the BIS (value 50±5) was used for maintenance of anaesthesia. Haemodynamic parameters, wake-up conditions, duration of intubation, hospital stay and drug consumption were also recorded. For explicit ADS, patients were interviewed 24 hours after extubation. The amount of propofol used was 178 ± 11 ml in CPG-1 and 117 ± 6 ml in BPG-2, with a 34.26% reduction in BIS. The amount of isoflurane used was 39 ± 8 ml in CIG-3 and 25 ± 6 ml in BIG-4, corresponding to a 35.89% reduction in isoflurane requirements. This difference was statistically significant in BIS monitored anaesthesia compared to conventional anaesthesia. The duration of intubation was 2.2 ±1.27 and 2.3 ±1.49 hours in the BPG-2 and BIG-4 groups, respectively (p<0.05). BIS-assisted CABG surgery with adequate depth of anaesthesia (BIS 50 ± 5) prevents ADS, reduces anaesthetic need for anaesthetics and facilitates ultrafast (UFT) extubation.
Materials Science
Ghaith Y. Dakhil; Rana M. Salih; Awham M. Hameed
Abstract
In this article, the influence of infill ratio and infill pattern on the compressive strength and hardness of 3D printed polylactic acid (PLA) based polymer are studied. The fused deposition modelling (FDM) technique was used to produce the 3D-printed samples. In the current work, three specimens of ...
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In this article, the influence of infill ratio and infill pattern on the compressive strength and hardness of 3D printed polylactic acid (PLA) based polymer are studied. The fused deposition modelling (FDM) technique was used to produce the 3D-printed samples. In the current work, three specimens of each type have been tested with selected infill ratios (30, 50, and 70%) and infill patterns (line, gyroid, and trihexagon). A compression test was done using the general-purpose (EN772-1) manual compression testing machine for blocks, cubes, and cylinders by the standard specification (ASTM D695), and hardness shore-D was tested by using a hand-held durometer (Shore Instruments, Type D), by ASTM D2240-05 (2010) type D. The data were collected and processed. The results showed that the 70 percent infill ratio with a linear pattern had the highest compressive strength. On the other hand, the hardness test shows that the maximum hardness value was found at the base side of the specimens.
Materials Science
Huda Jabbar; Enas Muhi; Tahseen Hussien
Abstract
Highly porous kaolin ceramics composites were produced by adding space-holder materials during dry pressing. To increase the strength of porous kaolin ceramic composites different ratios of cobalt-nickel ferrite nanoparticles (5, 10, 15, and 20%) were added. The sol-gel auto-combustion method prepared ...
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Highly porous kaolin ceramics composites were produced by adding space-holder materials during dry pressing. To increase the strength of porous kaolin ceramic composites different ratios of cobalt-nickel ferrite nanoparticles (5, 10, 15, and 20%) were added. The sol-gel auto-combustion method prepared the nano cobalt-nickel ferrite particles (CNF). Space-holder materials were removed by preheating, and solid specimens were produced by sintering. X-ray diffraction (X-RD) and Fourier transform infrared spectroscopy (FT-IR) was used to examine the structural characteristics. Up to 47.05% porosity was achieved when 20% CNF was added to the porous kaolin ceramics composites. The results indicated that the higher percentages of nano CNF 20% decreased linear shrinkage and the loss of ignition by 4.4% and 30.4%, respectively. While increased apparent density and diametrical strength of 1.42 g/cm3, and 9.03MPa respectively. Diametrical strength nanoparticles increased the strength attributed to the formation of a secondary phase in the porous ceramics, improving the crack bridging mechanism.
Materials Science
Israa F. Ghazi; Jawad K. Oleiwi; Sihama I. Salih; Mohammed A. Mutar
Abstract
In this work, it was evaluated the wear resistance, hardness, and surface roughness values of resin-based composites that applied in dentistry as restorative materials. The resin composites were made from six types of resin matrixes (A, B, C, D, E, and F) and each one of them has contained different ...
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In this work, it was evaluated the wear resistance, hardness, and surface roughness values of resin-based composites that applied in dentistry as restorative materials. The resin composites were made from six types of resin matrixes (A, B, C, D, E, and F) and each one of them has contained different types and ratios of monomers as well as the inorganic nano-fillers (SiO2, ZrO2, HA, and Al2O3). For each test, thirty specimens were prepared, which were classified into six groups depending on the types of the resin matrix and fillers used in the composites. The results prove that the nanocomposites that have the lowest rate of wear were the group E which was derived from the resin matrix of the group E that has monomers are (BIS-GMA, meth acrylamide, methacrylic acid, and 1-6 hexanediol methacrylate) with values range from 8.11 to 6.11 mm3/mm depending on the filler type material. All prepared composites resin materials (A to F) showed an increase in their hardness values as regards the reference, group D showed the highest hardness value followed by group B while group C was the lowest. The highest mean roughness was shown in groups A and F with 0.82 and 0.79 μm respectively, while the smoother surfaces among all groups were groups B and D which had significantly fewer roughness values of 0.16 and 0.19 μm respectively.
Materials Science
Mohsen Hosseini
Abstract
Natural gas has recently drawn considerable attention due to its low emissions upon combustion. Pipeline transmission of natural gas is costly and always encounters different obstacles. Therefore, an effective industrial alternative for the storage and transmission of natural gas is needed. Hydrates, ...
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Natural gas has recently drawn considerable attention due to its low emissions upon combustion. Pipeline transmission of natural gas is costly and always encounters different obstacles. Therefore, an effective industrial alternative for the storage and transmission of natural gas is needed. Hydrates, also known as solidified natural gas, have been proven to be a more feasible replacement compared to pipeline transmission, CNG, or LNG. Scientists have introduced promoters to shorten the induction time, increase the storage capacity, and improve the stability of hydrates. Nanostructure materials have demonstrated promising promotion results, suggesting a bright future and a critical step in the industrialization of this technology. Researchers have mainly used pure methane, which is the main component of natural gas, to form hydrates. In this article, the fundamentals of the selection of a nanopromoter, the hydrate formation process, and related calculations are demonstrated. Finally, recent results have been brought together to provide an overview of advances towards the use of nanostructure promoters to tune hydrates for future industrial processes.
Materials Science
Saja A. Kadhim; Awham M. Hameed; Rashed T. Rasheed
Abstract
In this study, using potassium polyacrylate (KPA), polyvinylalcohol (PVA), and zinc chloride as cross-linking agents, successfully synthesized novel superabsorbent polymers. Different weight ratios of KPA and PVA were used to prepare the polymers using polymerization solution. So, polymers with different ...
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In this study, using potassium polyacrylate (KPA), polyvinylalcohol (PVA), and zinc chloride as cross-linking agents, successfully synthesized novel superabsorbent polymers. Different weight ratios of KPA and PVA were used to prepare the polymers using polymerization solution. So, polymers with different weight ratios made from PVA and KPA. Superabsorbent polymers (SAPs) were produced using a simple approach at ambient temperature. By comparing absorption peaks, Fourier transform infrared spectroscopy (FTIR) and UV analysis were utilized to investigate the molecular interactions. The morphology of superabsorbent polymers was investigated by scanning electron microscopy (SEM). According to FT-IR, UV, and SEM results, the superabsorbent polymers (Zn-KPA and Zn-PVA) were prepared successfully. A comparison of Zn-KPA and Zn-PVA SAPs was conducted. The effects of cross-linking on water absorption were investigated. The Zn-PVA superabsorbent polymer has a maximum swelling capacity of 407%, while the swelling ratio of the Zn-KPA was 304%. Thus, these prepared superabsorbent polymers could be used for agricultural applications such as water storage. With increasing zinc chloride content and time, superabsorbent polymers’ swelling capacity has considerably improved.
Materials Science
Farhan A. Mohammed; Evan T. Salim; Azhar I. Hassan; Mohammed H. A. Wahid
Abstract
Using a chemical spray technique, an n-type WO3 polycrystalline thin film was prepared with optimizing parameters (molarity concentration of 80 mM and a substrate temperature of 350 °C). Study the physical properties of WO3 thin film via UV-Visible spectroscopy, XRD, Field Emission-Scanning Electron ...
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Using a chemical spray technique, an n-type WO3 polycrystalline thin film was prepared with optimizing parameters (molarity concentration of 80 mM and a substrate temperature of 350 °C). Study the physical properties of WO3 thin film via UV-Visible spectroscopy, XRD, Field Emission-Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy, Atomic Force Microscopy, and current-voltage. Tungsten oxide was deposited on glass surfaces at different molarities ranging from 50–90mM. In the UV-Visible spectrum of the WO3 thin film, it was found that the transmittance, reflectivity, and energy gap decreased (78%–53%), (9.63%–5.02%), and (3.40eV–2.63 eV), respectively. The X-ray diffraction of the WO3 film at the optimized was poly-crystalline and had a monoclinic phase, and the preferred orientation (hkl) was 200 at 2 = 24.19. From the image FESEM and EDX, it was found that it has a multi-fibrous network. The average diameter of the fiber is 266 nm, and the ratio of tungsten to oxygen (W/O) is 2.6, with a stoichiometric of 68.6% at the 80 mM concentration. The Atomic Force Microscopy shows that the WO3 thin layer has a nanostructure. The average surface roughness was 5.3 nm, and the Root Mean Square was 8.6 nm. The WO3 film had the lowest resistivity value of 2.393 × 108W cm, and the activation energy was 0.298 eV, among the parameter of the current voltage at substrate temperature and concentration optimum.
Materials Science
Zahraa A. Hussein; Zaidoon M. Shakor; Mohammed Alzuhairi
Abstract
Nowadays, sustainable energies can be found by thermal and catalytic pyrolysis of plastic waste. This study uses high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) to investigate thermal and catalytic pyrolysis ...
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Nowadays, sustainable energies can be found by thermal and catalytic pyrolysis of plastic waste. This study uses high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) to investigate thermal and catalytic pyrolysis using a stainless-steel semi-batch reactor at different conditions: Temperatures (350 - 500°C) and residence times (60, 90, and 120 min). The catalysts were undergone to different characterization techniques such as EDX, SEM, and BET that revealed the PR.9 catalyst consists of Cobalt, Molybdenum, and Platinum loaded on Al2O3. Whereas, the chemical compositions of Platinum RG-412 catalyst contain Chlorine and Platinum. The SEM analysis showed that the PR.9 catalyst is more active than RG-412 for the degradation of plastics. In addition, the properties of the liquid products like density, API, and viscosity were studied. As a result, the properties of the liquid produced by the plastic pyrolysis were similar that those produced from the petroleum refineries. The API findings declared that almost all of the liquids produced were light products, which contain mainly diesel oil, gas oil, kerosene, and gasoline.
Materials Science
Teba M. Hameed; Balqees M. Al-Dabbagh; Ragdaa K. Jasim
Abstract
In this research, composite material consist of PMMA and MMA as a matrix materials was prepared and reinforced by natural fibers (sisal fibers) in different concentrations (5, 10%wt). The conventional processing technique for complete dentures was followed to prepare the composite specimens. FTIR test ...
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In this research, composite material consist of PMMA and MMA as a matrix materials was prepared and reinforced by natural fibers (sisal fibers) in different concentrations (5, 10%wt). The conventional processing technique for complete dentures was followed to prepare the composite specimens. FTIR test was carried out to reinforcement material (sisal fibers) before and after salinization to determine, whether or not there is chemical bond between reinforcements materials and saline coupling agent. Physical tests such as thermal conductivity, water sorption and solubility were performed on all specimens. The results refer to a highly significant differences in: thermal conductivity, water sorption and solubility of reinforced specimens compared with pure specimens. Increasing the fiber concentration showed a slight decrease in the thermal conductivity of PMMA specimens reinforced with sisal fibers, and increase both water sorption and solubility of composite specimens. FTIR results showed a new absorption band was developed after sialne treatment.
Materials Science
Mostafa M. Ibrahim; Mustafa A. Hassan; Khaleel I. Hassoon
Abstract
In this work, the physical properties of iron sulfide (FeS2) thin films deposited by the chemical spray-pyrolysis (CSP) technique were studied. The thin films are deposited on glass substrates at 200oC, using FeCl3 salt with thiourea (NH2)2CS as precursors. Structural analysis of X-Ray diffraction ...
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In this work, the physical properties of iron sulfide (FeS2) thin films deposited by the chemical spray-pyrolysis (CSP) technique were studied. The thin films are deposited on glass substrates at 200oC, using FeCl3 salt with thiourea (NH2)2CS as precursors. Structural analysis of X-Ray diffraction manifested that the thin films contain two phases: Marcasite and Pyrite in planes (110), (111) at angles 2θ =26.3°, 2θ =28.3° respectively. Optical properties analysis showed that the prepared iron sulfide thin-films were highly absorbing in the UV-Visible range and the absorption coefficient was in the range of 1.6x105 cm-1 with a relatively low resistivity of about 0.49 (Ω.cm). The calculated activation energy (Ea) was 0.024 eV and the bandgap value was 2.45 eV. Moreover, the FeS2 thin films were also deposited on (CdO) to fabricate a heterojunction photocell. In conclusion, there is the feasibility of preparing low-cost and highly absorbing iron sulfide (FeS2) thin films for optoelectronic applications with acceptable homogeneity using the spray-pyrolysis technique.
Materials Science
Hajer A. Ali; Nahida J. Hameed
Abstract
To develop bio-packaging materials, nanocomposite films of cellulose acetate reinforced with titanium dioxide and zinc oxide nanoparticles were prepared, by the casting method at different weight ratios of ZnO nanoparticles (1.5, 2, and 2.5) wt% and a constant weight ratio of 2 wt% TiO2. ZnO and TiO2 ...
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To develop bio-packaging materials, nanocomposite films of cellulose acetate reinforced with titanium dioxide and zinc oxide nanoparticles were prepared, by the casting method at different weight ratios of ZnO nanoparticles (1.5, 2, and 2.5) wt% and a constant weight ratio of 2 wt% TiO2. ZnO and TiO2 nanoparticles were tested using scanning electron microscopy (SEM). The mechanical properties (tensile strength and elongation) were improved at a fixed level of Cellulose Acetate+ 2% TiO2+1.5wt% ZnO loading. Beyond that level of loading, they decreased. The tensile strength was decreased due to some degrees of agglomeration of filler particles above a critical content. Fourier-Transform Infrared Spectroscopy (FTIR) was conducted to reveal the microstructures and chemical composition of as-prepared composite films. The wettability of the films was also determined by the sessile drop method. An increase in contact angle was also observed by the addition of ZnO content from 70.6° to 77.1° compared to pure Cellulose Acetate, which indicated a value of 61.3°. Antibacterial activity against Escherichia coli and Staphylococcus aureus was enhanced after incorporation of ZnO-TiO2 compared with pure CA. The enhanced wettability and antibacterial activity of the prepared films suggest that they could be used for packaging applications.
Materials Science
Ishraq A. Fadhil; Balqees M. Aldabbagh; Wijdan T. Mahdi
Abstract
Chitosan holds net ionic positive charges, which contribute its ability to chemically bind with negatively charged fats, lipids, metal ions, proteins, and microorganisms. Magnesium oxide (MgO) nanoparticles are important inorganic materials with a wide band-gap used in many applications such as catalysts, ...
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Chitosan holds net ionic positive charges, which contribute its ability to chemically bind with negatively charged fats, lipids, metal ions, proteins, and microorganisms. Magnesium oxide (MgO) nanoparticles are important inorganic materials with a wide band-gap used in many applications such as catalysts, antibacterial and medical products. The aim of this study was to investigate the effect of Chitosan (CHT) hydrogel loaded MgO nanoparticles on the bacterial growth. CHT/ poly vinyl alcohol (PVA)/ poly ethylene glycol (PEG) hydrogel was blended with various amounts of MgO nanoparticles. The surface morphology of the obtained blends was investigated by Field Emission Scanning Electron Microscope (FE-SEM). Evidently, surfaces with appropriate roughness were obtained for most of the prepared hydrogels. Fourier Transform Infrared Spectroscopy (FT-IR) and Energy Dispersive X-Ray analysis (EDX) were also included in this paper. Thermal properties of all samples was studied by DSC-TGA curves. The antibacterial activity of the prepared hybrids CHT/PVA/PEG/MgO nanoparticles have performed against gram positive bacteria Staphylococcus aureus (S.aureus) and Streptococcus, as well as gram negative bacteria Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E.coli). In this study, MgO nanoparticles various proportions presented high efficiency towards gram positive microorganisms. High resistance of gram negative bacteria against the final products was extremely detected according to measured inhibition zones which were between (0-9) mm.
Materials Science
Zainab B. Abd; Nasser A. Habib; Abbas khammas
Abstract
The modified Graphene Oxide (GO) synthesis methods used over the past sixty years is contributed mainly to improving its characteristics and increasing its advanced applications. Therefore, in this work, modifying Hummer’s Method via oxidizing graphite flakes using one type of acid (H2SO4) was ...
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The modified Graphene Oxide (GO) synthesis methods used over the past sixty years is contributed mainly to improving its characteristics and increasing its advanced applications. Therefore, in this work, modifying Hummer’s Method via oxidizing graphite flakes using one type of acid (H2SO4) was performed without any chemical agents. Also, ultra-sonication and filtration were implemented with optimal parameters (50 kHz frequency during 120 minutes at room temperature 30 oC) to prepare GO nanosheets. These procedures improved GO characteristics via analyzing; Particle size, X-ray diffraction pattern (XRD), Ultra-violet visible (UV-vis) absorption, and Scanning Electron Microscopy (SEM). The obtained results showed that the characteristics of GO nano-sheets had met the preparation requirements, such as reducing the average diameter of GO nano‑sheets from 313 nm to 94 nm. Moreover, characterizing the diffraction angle of GO at 9.86o and the optimal absorption by UV-vis achieved at 230 nm. The synthesis and exfoliation of GO nano-sheets were carried out with fewer impacts of toxicity using distilled water. Finally, this GO synthesis in the lab might be used to make a variety of nanocomposites.
Materials Science
Sahar I. Ahmed; Aqeel S. Al-Adili; Awham M. Hameed
Abstract
Conventional concrete is recognized for its high density, which leads to a higher cost of building foundations and columns. Recently, many efforts have been made to produce lower density concrete with acceptable and applicable mechanical properties. One option can reduce the density of the conventional ...
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Conventional concrete is recognized for its high density, which leads to a higher cost of building foundations and columns. Recently, many efforts have been made to produce lower density concrete with acceptable and applicable mechanical properties. One option can reduce the density of the conventional concrete by using partial or total replacement of porcelanite instead of natural gravel. Porcelanite aggregate concrete can be prepared by adding different ratios of porcelanite and several other additives to the mortar, depending on the required density of the prepared porcelanite concrete. This study aims to assess porcelanite aggregate concrete components, manufacturing methods, and features of porcelanite aggregate concrete. Furthermore, this literature review aims to appraise and provide a complete vision of the testing program, including compressive strength, density, porosity, splitting tensile strength, and water absorption of porcelanite aggregate concrete. Also, this paper focuses on studying the development and applications of the porcelanite aggregate concrete, which will be presented in detail through this study.
Materials Science
Faten Hasan Gata; ENAS MHUI
Abstract
In this paper, Mortar was prepared from medium alumina refractory grog, bricks crashed as a mean material to a particular size, and Iraqi raw (kaolin or bentonite) as binding materials. Refractory bricks were crushed, milled, then sieved to three particle sizes: fine as (1.18 >fine> 0) mm, medium ...
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In this paper, Mortar was prepared from medium alumina refractory grog, bricks crashed as a mean material to a particular size, and Iraqi raw (kaolin or bentonite) as binding materials. Refractory bricks were crushed, milled, then sieved to three particle sizes: fine as (1.18 >fine> 0) mm, medium as (2.36 > medium > 1.18) mm, crushed as (400 > coarse > 2.36) mm. Then these particle sizes were mixed with Iraqi raw kaolin or bentonite with selected ratios (10,15,20,30 and 40) %. Specimens were formed by the wetting method, then drying it at laboratory temperature for one day, followed by firing it at 1200 ℃. Results showed that the porosity of specimens decreases when increasing the clay ratio from 3-4% (kaolin or bentonite), and the bond strength between grog and clay increases when increasing the clay ratio from 2-3% (kaolin or bentonite). Also, the diametrical strength increases when increasing the clay ratio from 4-7% (kaolin or bentonite). The thermal shock results showed that K-mortar is better than B-mortar, depending on the results we obtained through the effect of temperature and diametrical strength. The SEM results showed that mortar structure was produced by adding 40% bentonite with small irregularly shaped. The mortar was produced by adding 40% of kaolin which possesses regular mullite crystals. Finally, the results of the test EDS that K-mortar were revealed in showed that there is no adsorption of carbon while B-mortar showed that there is adsorption of carbon atoms.
Materials Science
Ghadeer Sadiq Jassim; Mojahid Najim; Wafaa Salih
Abstract
In this paper, a homogenous pure Barium Titanate with formula (BaTiO3) was prepared from pure Barium Carbonate (BaCO3) and titanium dioxide (TiO2) using the solid-state reaction technique, were used as raw materials having micro size by mixing of molar ratio [1:1], the powder was calcined at temperatures ...
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In this paper, a homogenous pure Barium Titanate with formula (BaTiO3) was prepared from pure Barium Carbonate (BaCO3) and titanium dioxide (TiO2) using the solid-state reaction technique, were used as raw materials having micro size by mixing of molar ratio [1:1], the powder was calcined at temperatures (900-1350) °C. The solid-State reaction can consider as an attractive process realistic alternative to the expensive wet-chemical route, according to X-ray diffraction, all of the peaks of Barium Titanate powder were perfectly suited to the positions of the peaks of the standard tetragonal phase in the pattern for this process. And with preferred crystalline size for the powder calcined at 1350 °C manifested the best results, where all the peaks indicate the formation of Barium Titanate completely. In addition, each BaTiO3 Nanopowder was compared to a micro powder that had been manufactured, by conducting x-ray diffraction, diffraction peaks undergo shifting toward higher angle to the high value of 2Ө, and Nano powder particles are smaller than micro powder particles. And this refers to a decrease in lattice parameters, in terms of the peaks of the Nano powder preceding the peaks of the micro powder of BaTiO3 and that match the result that is obtained by scanning electron microscopy (SEM).
