In the friction stir welding process, preferred joint property is vastly reliant on the selection of optimal welding conditions. The present study aims to use the Taguchi technique to , nd the optimal process conditions for achieving superior Ultimate Tensile Strength (UTS) in friction stir welded Aluminum Matrix Composite (AMC) joints. AMCs reinforced with rutile particles which have a potential application in the aerospace, automotive, and marine industries are used in the present work. Taguchi parametric design technique was used to identify the effect of rotational speed, tool traverse speed, and tool geometry on joint strength. Taguchi approach confined the optimum level of process variables and these variables were optimized. The investigation showed that the parameters within the selected value range will seriously affect the output. The predicted value of the output response was 155. 48 MPa, which was validated by further experiments using the optimum process variables. Analysis Of Variance (ANOVA) results indicated that the UTS of the composite joint is mainly affected by the tool traverse speed followed by rotational speed, and tool geometry. The microstructural study unveiled that grain size is dependent on process variables and , finer grains offer better joint properties.

The survey employs deep log analysis techniques, a more sophisticated form of transaction log analysis, and Data mining algorithms (Association Rules) to demonstrate what usage data can unfold about information seeking behavior of Information center of UTS University in Australia. To meet this goal, we work with the raw server log data which had been gathered on the server. The information seeking behavior of nearly several millions of users is analyzed in respect to the extent to which they penetrate the site, the number of visits made, as well as the type of items and content they viewed or downloaded and when they connected to the web site. The users are broken down by their field of study, geographical location, type of databases they used, the number of items viewed in a session and type of products downloaded. This Article will offer a good knowledge about how IT managers can make their decision to subscribe Databases or change their policy in a better way.

Background and Aim: Elastomeric ligatures are used to secure archwires into orthodontic brackets, but color changing and deformation and at last torn of them is the most current problem . Due to the lack of knowledge about effect of mouth rinse on the mechanical properties of ligatures, goal of this study was to compare the effect of Oral-B and Orthokin mouth rinse on Ultimate Tensile Strength (UTS) of elastomeric ligatures in 2009 .Materials and Methods: This experimental laboratory-based study was carried out on 100 transparent elastomeric ligatures of Dentaurom Company . After division of ligatures in three groups of Oral-B, Orthokin and artificial saliva, Ultimate Tensile Strength of 10 ligatures from each group were measured after 1, 7 and 28 days and also ten ligatures in as received condition using H & P Testing Machine with 5 mm/min cross head speed . Data were subjected to ANOVA and lSD test .Results: Results showed no significant difference in UTS between Three times in artificial saliva group . UTS in Oral-B and Orthokin group was the least after 28 days, also UTS in three groups after 1, 7, 28 days compared to as received condition has a significant decrease.Conclusion: UTS of elastomeric ligatures decreased after using in different conditions and has a significant decrease in all groups . Thus there is no different between using Oral-B and Orthokin, and it is recommended that all ligatures should be replaced at each visit to reduce risk of tearing.

Hydroxyapatite is a biocompatible ceramic and reinforcement for bone implantations. SEVA/HAP composite content HAP filler with difference particle sizes were designed. Mechanical tests like tensile modulus, UTS, strain at break and biodegradation were investigated. Results illustrated much increase tensile modulus of composites content HAP nano powders ratio to micro powders. Also UTS analysis of composites illustrated much increase UTS of composites content HAP nano powders ratio to micro powders and strain at break analysis of composites illustrated much decrease of strain at break composites content HAP nano powders ratio to micro powders. The composites degradation in PBS solution showed slowly degradation time of composites content HAP nano powders ratio to micro powders filler.

The objective underlined in this work is to apply Rotary Friction Welding (RFW) process to joint similar AA2024 and TiAl6V4 welds. The experiment is conducted by varying the input parameters (rotational speed, friction pressure and friction time) using Taguchi’s L9 orthogonal array method. MINITAB software was used to plot the response chart. The output parameter considered in this approach is the Ultimate Tensile Strength (UTS) of the weld joint, where the optimum RFW condition for maximizing the UTS were determined. Besides, the most influential process parameter has been determined using statistical analysis of variance (ANOVA). Finally, the general regression equations of the UTS for both materials are formulated and confirmed by means of the experimental tests values.

The aim of this study is to investigate the fatigue behavior of GFRP composite with biaxial fiber orientation [0,90] under different stress levels. First, the tensile test was performed and the UTS value was 420 MPa. Then, fatigue test was performed at 4 stress levels of 70, 50, 42 and 35% of UTS. Fatigue results had acceptable dispersion and the fitting curve on the data also matched well. Finally, the fatigue failure structures of 70 and 35% of UTS samples, using scanning electron microscopy (SEM) were evaluated. The results showed that in both 70 and 35% samples, the mechanism of pull out fibers was obsvered but its intensity was higher in 35% sample. Also in the 35% sample, significant distortion was observed which was absent in the 70% sample. On the other hand, the brittle failure of matrix was more pronounced in the 70% sample than in the 35% sample. This can be related to the increase of the matrix softness due to the application of cyclic load.

The main aim of this experiment is to determine the mechanical and microstructural of using Nano powder of Al2O3 besides stir welding of Al2024-T6 in multi-pass welding. Nanoparticles welded nine specimens and one particle-free in 1400 rpm rotational speed and 16 mm/min traveling speed. A combination of volume percentage of powder (3%, 5%, and 7%) and three different multi continuous passes (1, 2, and 4) is applied for Nano-rich specimens. The microstructure of joint, micro hardness and ultimate tensile strength (UTS) of the welded joint has been studied. It was observed that by increasing the particle volume from 3% to 7% average grain size increased extremely to 37% and UTS to 10%, and in the staid situation of welding passes, average micro hardness has 10% increase in shoulder affected zone. The result showed that the specimen with 7% of Nanoparticles in two passes has the highest mechanical and metallurgical properties and has a significant decrease (55%) in average grain size compared with a particle-free specimen. Meanwhile, UTS and average micro hardness of the same specimen was about 11% and 48% more than particle free.

The main aim of this experiment is to investigate the effects of Nano-size Al2O3 on the mechanical properties and microstructure of multi-passes friction stir welding of Al 2024 lap joint. Nano  particles were added into the joint line. A combination of rotational speed and travelling speeds were performed. Optical microscopy and scanning electron microscope were used to investigate the microstructure and fracture surface of samples respectively. Optimum condition (sample) was selected due to highest ultimate tensile strength (UTS). It was seen that sample which included Nano particles and fabricated by 1400 rev/min rotational speed and 16 mm/min travelling speed in second pass of continues welding had improvement in UTS in comparison to one pass welded sample of particle free and after that increasing the number of passes reduce the UTS. The average micro hardness of the sample which was particle rich were increased in comparison to particle free sample in nugget zone. Increasing the number of passes was not effect average micro hardness in nugget zone signiicantly. Grain sizes were reduced by 2 passes welding and after that no significant reduction has been seen.

In the present study, a technique has been addressed in order to model and optimize gas tungsten arc welding (GTAW) process which is one of the mostly used welding processes based on the high quality fabrication acquired. The effects of GTAW process variables on the joint quality of AISI304 stainless steel thin sheets (0. 5 mm) have been investigated. The required data for modeling and optimization purposes has been gathered using Taguchi design of experiments (DOE) technique. Next, based on the acquired data, the modeling procedure has been performed using regression functions for two outpUTS,namely, heat affected zone (HAZ) width and ultimate tensile stress (UTS). Then, analysis of variance (ANOVA) has been performed in order to select the most fitted proposed models for single-objective and multi-criteria optimization of the process in such a way that UTS is maximized and HAZ width minimized using simulated annealing (SA) algorithm. Frequency, welding speed, base current and welding current are the most influential variables affecting the UTS at 22%, 21%, 20% and 17% respectively. Similarly, base current, welding current, frequency and welding speed affect the HAZ at 28%, 20%, 16%, and 15% respectively. Based on the results considering the lowest values for current results in the smallest amount of HAZ. By the same token in order to acquire the largest amount of UTSs the highest values of current must be considered. Setting welding and base current, frequency, speed, and debi at 42 and 5 apms, 46 Hz, 0. 4495 m/min, and 5 lit/min respectively resulted the optimized HAZ and UTS simultaneously. The proper performance of the proposed optimization method has been proved through comparison between computational results and experimental data with less than 6% error.

Background and Objective: Starch-based biopolymer films have disadvantages such as poor mechanical and barrier properties against water vapour that restrict their application in packaging. To improve the properties of starch-based films, different methods such as blending with other polymers and adding nanofillers have been suggested. Cellulose nanocrystals (NCC) are a suitable candidate for reinforcing starch biopolymers due to their biodegradability, nontoxicity, abundance in nature, low price, and renewability. The objectives of the current research were to investigate the effects of NCC and polyvinyl alcohol (PVA) on the properties of starch-based films to improve their mechanical and barrier properties.Materials and Methods: NCC was produced from cotton linter and added to the starch-PVA filmforming blend. Tests used to determine the properties of the films thus produced included mechanical, water- vapour permeability, thermal property, X-ray diffraction (XRD), and transmittance electron microscopy (TEM) tests.Results: Addition of PVA and NCC to film-forming solutions caused an increase in the maximum tensile stress (UTS) and a decrease in water-vapour permeability and solubility of the nanobiocomposit films. In addition, the XRD test showed that the 2 components− polymer matrix and nanofiller – were well dispersed in the blend. The optimum structure was observed at a concentration of 10% NCC.Conclusion: Polyvinyl alcohol has OH groups and, hence, it can form hydrogen bonds with the starch OH groups, resulting in enhanced mechanical strength of polymer and improved mechanical and barrier properties of the biocomposite produced. Due to their high crystalline structure (as a result, high rigidity and elastic modulus) and their ability to form strong hydrogen bonds with starch and PVA, cellulose nanocrystals can potentially improve the mechanical and barrier properties of starch-based bionanicomposite films. The starch-based nanocomposites showed the highest UTS at a concentration of 10% NCC. At higher concentrations the UTS decreased, which could be attributed to aggregation of NCC in the polymer matrix. Aggregation of NCC at a level of 15% or 20% was observed as shown by XRD pattern peaks.