This work studies the protection from corrosion in the inner surface of petroleum storage tanks by applying nano-coating on the AISI1018 steel type used in these tanks. BNi-2 alloy, used as coating layer, was deposited using the DC sputtering technique to obtain protection layers of nano-coating. The cyclic potential dynamic polarization technique is used to study and evaluate the resistant metal to localize corrosion, for example, pitting and crevice corrosion. The samples were evaluated in a 3.5% NaCl aqueous solution using the polarization method to determine the corrosion rate. The input parameters of deposition included ion current 16 mA, vacuum 10-1
mbar, time of deposition was 60 minutes, and the distance between target and substrate was 2.5 cm. The surface roughness of the uncoated specimens was (0.1466 µm), and after coating, it decreased to (0.0933µm). The most important factor that affects the corrosion of the coated steel surface is the surface topography of steel before coating, as it is known that the spattering process coats the facing surface to target better than the inclined surface topography. Therefore, some micro scratches non-coated well worked as nucleation for corrosion as detected in stereo microscope images for coated and uncoated surfaces. By calculating the corrosion rate from cyclic potential dynamic polarization for coated and uncoated workpieces, pitting and crevice corrosion improved approximately ten times compared to the uncoated AISI1018 steel surface.
In this work, the cyclic expansion extrusion (CEE) process was applied to ZK60 Mg alloy. The correlation between the evolved microstructure and mechanical properties was investigated. The CEE process was performed at a constant ram speed (15 mm/min) and at different processing temperatures (190, 270, and 350 °
C). Optical and scanning electron microscopes, X-ray diffraction instruments, Vickers hardness tester, and tensile testing machine were utilized to examine the influence of CEE processing temperature on the characteristics of ZK60 Mg alloy. The XRD analysis showed that two phases were presented in the matrix of ZK60 Mg alloy, namely α-Mg and MgZn2,
in small amounts. The CEE process reduced the size of α-Mg grains due to dynamic recrystallization, especially at the processing temperature of 190 °
C. A slight coarsening of the α-Mg grains was observed with increasing processing temperature to 270 and 350 °
C. The hardness value of ZK60 Mg alloy was enhanced by about 11 to 19% using the CEE process compared to the as-extruded sample. The processing temperature greatly affected the mechanical properties, where a significant improvement of about 24% yield strength, 9% ultimate tensile strength, and 38% elongation was observed using a processing temperature of 190 °
C. The characterization of the tensile fracture surface of the tested samples indicated that the ductile-brittle fracture mode was responsible for the failure.
One of the polymeric membranes' main limitations is their susceptibility to fouling, lowering the membrane's performance with time. Therefore, incorporating nanomaterials in polymer matrices has attracted great attention in wastewater treatment applications. It's a promising approach for enhancing membrane hydrophilicity and performance. Herein, ultrafiltration nanocomposite membranes were synthesized by applying the phase inversion method through immobilizing (0.1-0.4 wt.%) tungsten oxide (WO2.89
) nanoparticles in a polyether sulfone (PES) matrix. Membrane's anti-fouling performance was evaluated against tinzaparin sodium. The data showed that the pure water flux improved with increasing nanoparticle loading, reaching its optimum value of 54.9 kg/m2
h at 0.4 wt.% WO2.89
nanoparticles compared to the neat membrane's 30.42 kg/m2 h. The results also demonstrated that the rejection efficiency and flux recovery ratio (FRR) against tinzaparin sodium was enhanced, by 44.89% and 12.69%, respectively, for the membranes modified with 0.4wt.% WO2.89
nanoparticles loading compared to the neat PES membrane. The data also showed that after exposing the nanocomposite membranes to UV light irradiation (λ=365 nm) and intensity (1200mW/cm2
) for 1h, a further enhancement by 8.34% in FRR as compared to the membranes with the same percentage of nanoparticles loading without irradiation. It is concluded that the photocatalytic activity of WO2.89
nanoparticles in the decomposition of organic molecules on/close to the membrane surface was the impact that caused this improvement in membrane anti-fouling property
A pulsed Nd:YAG laser with a fiber optic delivery system was used to accomplish a dissimilar joining of 316 stainless steel (SUS316) to polyethylene terephthalate (PET). Laser Conduction Welding (LCW) was applied as a welding technique to achieve a lap metal/polymer joint by applying the laser from the metal side. The heat was transferred from the metal layer to the polymer layer, which caused the melting and then solidifying of the polymer at the interface. The effect of three welding parameters, laser energy density, pulse duration, and welding speed, on joint force, was studied and discussed. To measure the joint force tensile shear test was conducted. Furthermore, the Taguchi method was used as a design experiment method to optimize the welding parameters by designing an orthogonal L9 matrix. The signal-to-noise ratio of each trial was calculated and plotted. The best welding parameters that gave the highest joint force were achieved. The maximum tensile force obtained was 525 N at 250 J/cm2
energy density, 15 ms pulse duration, and 20 mm/min welding speed. Finally, the comparison between the weakest and the strongest joints was carried out to show the difference between welding with the optimal parameters and any other set of parameters.
Hydroxyapatite (HA) is one of the important biomaterials in the medical field, especially in bone treatment, because of its biological properties close to human bone. A simple co-precipitation technique was used to integrate neodymium and zinc into HA by adding neodymium nitrate and zinc nitrate as a source of substituted elements during synthesis through the wet precipitation method with controlled temperature and pH. Finally, substituted HA was sintered at 800°C after completing the biomaterial preparation. The resulting Nd-Zn/HA was globe-like with nanoparticle size. The Ca+Nd+Zn/P ratio was equal to 1.63, which is relatively close to the molar ratio of bone. Also, the ability of Nd-Zn/HA to cause apoptosis in osteosarcoma cells was discovered. The anti-tumor actions are amplified when increasing the concentration of substituted HA. Therefore, Nd-Zn/HA is a potentially effective biomaterial in osteosarcoma treatment. Meanwhile, it has antibacterial and fungicidal properties against Staphylococcus aureus
, Staphylococcus epidermidis
, Streptococcus mutans
, Escherichia coli
, and Candida albicans
—one of the important properties required in biomaterials to protect the part that is being treated after the biomaterial is implanted inside the body. The inhibition zone of Nd-Zn/HA ranged between (20-31)mm, much higher than gentamicin and nystatin.
In the mobile robot workplace, the path planning problem is crucial. Robotic systems employ intelligence algorithms to plan the robot's path from one point to another. This paper proposes the fastest and optimal path planning of the wheeled mobile robot with collision avoidance to find the optimal route during wheeled mobile robot navigation from the start point to the target point. It is done using a modern meta-heuristic hybrid algorithm called IPSOGWO by combining Improved Particle Swarm Optimization (IPSO) with Grey Wolf Optimizer (GWO). The principal idea is based on boosting the ability to exploit in PSO with the exploration ability in GWO to the better-automated alignment between local and global search capabilities towards a targeted, optimized solution. The proposed hybrid algorithm tackles two objectives: the protection of the path and the length of the path. During, Simulation tests of the route planning by the hybrid algorithm are compared with individual results PSO, IPSO, and GWO concepts about the minimum length of the path, execution time, and the minimum number of iterations required to achieve the best route. This work's effective proposed navigation algorithm was evaluated in a MATLAB environment. The simulation results indicated that the developed algorithm reduced the average path length and the average computation time, less than PSO by (1%, 1.7%), less than GWO by (1%, 1.9%), and less than IPSO by (0.05%, 0.4%), respectively. Furthermore, the superiority of the proposed algorithm was proved through comparisons with other famous path planning algorithms with different static environments.
The study investigates the effect of polycaprolactone (PCL) concentration on the metformin hydrochloride (MH) release ratio of electrospun nanofiber scaffolds. Blend and emulsion electrospinning are used to produce the scaffolds. The performance of nanofibrous scaffolds was evaluated by morphology (Field Emission Scanning Electron Microscopy, FESEM), chemical (Fourier Transform Infrared Spectroscopy, FTIR), thermal (Differential Scanning Calorimetry, DSC), wettability, porosity, mechanical tests, and in vitro drug release. The average fiber diameter ranged from (189.29-2893.93 nm) according to the FESEM results, and it increased with PCL concentration. The average fiber diameter of the electrospun scaffold, prepared by the blend method (259.64±6.1 nm), is lower than that of the electrospun scaffold produced by the emulsion method (487.45±22.53 nm). Melting points of all drug-loaded scaffolds were identical to those of pure PCL polymer. Compared with blend electrospun nanofibers, emulsion electrospun nanofibers showed a marked increase in hydrophilicity. The tensile strength indicated an improvement in the mechanical properties with a decrease in the average fiber diameter. Moreover, the results show that the release of Metformin hydrochloride decreases with the concentration of polycaprolactone. Total MH release from (5% w/v) PCL-MH fibrous scaffolds for three-week was 71.11 % and 93.91 % from the emulsion and blend methods, respectively. The drug release ratio is lower in emulsion electrospinning than in blend because the drug is encapsulated by polymer and surfactant, which improves control and long-term drug delivery system DDS.
A full-dimensions 3-D numerical model based on the Lagrangian approach has been employed to predict the peak temperature and the plastic strain distribution in the FSW of (AA5754) joints using ABAQUS software. The material’s model utilizes the classical plasticity model in addition to defining the thermophysical properties of the alloy using JMatPro software to increase the accuracy of the numerical results. The basic variables of FSW were three rotational speeds (930, 1460, and 1860 rpm) and three traverse speeds (35, 65, and 95 mm/min). The influence of the rotational and traverse speed on temperature profile and plastic strain has been studied. The simulation results showed that increasing the rotational speed led to increasing the peak temperature, which concentrated under the tool’s bottom surface while increasing the traverse speed decreased the peak temperature recorded. The highest peak temperature was (497 o
C) at a rotational speed of (1860 rpm) and a traverse speed of (35 mm/min). It was also found that the rotational speed increased the plastic strain starting from the tool’s neck and continuing along the pins’ position and gradually decreasing towards the bottom. In addition, a V-shape pattern has appeared in the temperature distribution across the workpiece’s cross-section, representing the heat loss during the FSW by the backplate due to heat conductance.
To increase the erosion resistance of 2024 Al alloys, plasma nitriding surface treatment was used. Nitrogen and argon gases are injected into an evacuated chamber until the pressure reaches 15 Pa. The process requirements for normal plasma nitriding were heating at 440˚C for 8 hours, low voltage of 650 V, current of 25 mA, low gas consumption, and no air pollution. A continuous nitriding layer of AlN was formed. The microhardness reached a maximum value of 170 HV, about 3 times higher than that Al melts at, is transported upward through voids and capillaries in the AlN structures, and reacted with N plasma in the melt surface. The growth of the AlN structures promotes this transport of un-nitride alloy subjected to the same heat treatments. As a result, the erosion rate of the nitrided samples decreased by 10% when compared to the ones that are not nitrided.
Recently, geopolymers have received widespread attention due to their ability to completely replace ordinary cement with better efficiency, lower cost, and less damage to the climatic environment. This paper aimed to prepare MK-based geopolymer cement at ambient temperature with different alkaline activators and processing parameters. XRD, PSA, DTA-TGA, SEM, and other techniques have characterized the prepared samples. ANOVA test was employed to identify the main effect of the processing parameters. Results showed that the incorporation of potassium ions has a negative effect on the physical properties of GP, in which the presence of such ions tends to decrease the density of GP. Furthermore, the apparent porosity and water absorption were increased. For Na and K, Na-activated GP, it was also concluded that the density of GP increases by increasing Si/Al ratios. Despite the Na-based GP processes having a larger density in compared to the K, Na-based ones. The results also suggested a strong effect of the W\MK ratio on physical properties, in which decreasing this ratio is necessary to achieve GP with better properties. The findings also revealed that a one-minute mixing period was sufficient for producing a homogeneous and dense GP paste.
SMAs can switch from one crystallographic structure to another in response to temperature or stress stimuli. When SMAs are exposed to mechanical cyclic stress, they can absorb and discharge mechanical energy by experiencing a reversible hysteretic shape change. SMAs are widely used for sensing, actuation, impact absorption, and vibration damping. This work studied the effect of CeO2
addition on the transformation temperature and wear resistance of Cu-Al-Ni SMAs. WhereCeO2
was added at different percent’s 0.5, 1, and 3 wt% to the base alloy, followed by casting and homogenization at 900o
C. Some tests were carried out: Differential scanning calorimeter, Optical Microscope, Scanning Electron microscopy, Energy dispersion spectrometer, X-Ray Diffraction, and Wear and Hardness tests. OM and SEM tests reveal that both phases of martensite β and γ are found. Also, the additions of CeO2
show a visible effect on phase formation and transformation temperatures. It was observed that increasing of CeO2 particles in Cu-based SMAs owing to improve interfacial bonding between matrix and reinforcement and also observed that the variants become thicker with increasing in percent. Additions of different percentages of cerium oxide increase the hardness of Cu-Al-Ni SMAs. Due to the addition of CeO2
particles, the sample's wear rate decreases compared to pure SMAs.
Fused deposition modeling (FDM) is an additive manufacturing (AM) process often used to build geometrically complex prototypes and parts. It is becoming more popular since it improves products by eliminating the need for high-priced equipment. Materials, printing methods, and printing variables all impact the mechanical characteristics of printed items. The process parameters of FDM affect the parts' quality and functionality. This study examines the influence of different infill patterns on test specimens made of polylactic acid (PLA) tensile strength. Total of 10 different infill patterns (IPs): Grid, Lines, Triangles, Tri-Hexagon, Cubic, Gyroid, Zig-zag, Concentric, Octet, and Cubic subdivision were taken as process variables. Samples were printed using processing parameters (speed 60 mm/s, layer height 0.1 mm, infill density 80%, extruded at 200◦C). The ASTM D638 tensile test was used to determine the tensile strength based on this printing parameter. According to tensile test results, the infill pattern significantly affects the tensile strength. The results showed that the concentric infill pattern has a higher tensile strength of 32.174 MPa, whereas the triangles infill pattern has a lower tensile strength of 20.934 MPa.