1,176 research outputs found
Development of a virtual reality milling machine for knowledge learning and skill training
No full textCurrent methods of training personnel on high cost machine tools involve the use of both classroom and hands on practical training. The practical training required the operation of costly equipment and the trainee has to be under close personnel supervision. The main aim of this project is to reduce the amount of practical training and its inherent cost, time, danger, personal injury risk and material requirements by utilising a virtual reality technology.
In this study, an investigation into the use of Virtual reality for training operators and students to use the Milling Machine was carried out. The investigation has been divided into two sections: first the development of Milling Machine in the 3D virtual environment, where the real machine was re-constructed in the virtual space.
This has been carried out by creating objects and assembling them together. The complete Milling machine was then properly modelled and rendered so it could be viewed from all viewpoints.
The second section was to add motion to the virtual world. The machine was made of functions as for the real machine. This was achieved by attaching Superscape Control Language (SCL) to the objects. The developed Milling machine allows the users to choose the material, speed and feed rate. Upon activation, the virtual machine will be simulated to carry out the machining process and instantaneous data on the machined part can be generated.
The results were satisfactory, the Milling Machine was modelled successfully and the machine was able to perform according to task set. Using the developed Virtual Model, the ability for training students and operators to use the Milling Machine has been achieved
A comparative study of the etiology of adult mandibular fractures in the Sultanate of Oman and South Australia
No full textAl-Hashmi AK, Al-Ismaily MI and Goss AN.http://www.ncbi.nlm.nih.gov/pubmed/1908224
Temporomandibular disorders in patients with mandibular fractures: A preliminary comparative case-control study between South Australia and Oman
No full textA. Al-Hashmi, A. Al-Azri, M. Al-Ismaily, A. N. Gos
Peritoneal patch for retrohepatic vena cava reconstruction during major hepatectomy: how I do it
No full textTraumatic Bilateral Anterior Dislocation of the Mandible With Impaction Over the Maxilla: A Case Report
No full textAndrew Cheng, Ahmed Al Hashmi and Alastair N. Gos
Investigation into coatings produced from nanoparticle blended feedstock for rotating equipment repair applications
No full textCoating of carbon steel with conventional and nano particle blended feedstock material is considered in relation to repair applications of rotating equipment. Gas Metal Arc Welding (GMAW) and Wire Arc Spray (WAS) processes are used to produce the coatings on carbon steel workpieces. The wire arc sprayed workpieces are heat treated at temperature similar to the operating temperature of hot-path components of power gas turbines. The microstructure and metallurgy of the workpieces are examined using the Scanning Electron Microscope (SEM), Optical Microscope, Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD). The indentation tests are carried out to assess the microhardness variation across the coatings. In the case of coatings produced by GMAW, it is found that fine structures are formed in the coating due to the presence of nano particles and they resulted in increased microhardness of the coatings. In the case of the wire arc sprayed workpieces, the formation of dimples like structure at the surface increases the surface roughness of the coatings. In addition, the microhardness of the resulting coating is significantly higher than that of the base material. The heat treatment does not alter the microstructure and microhardness of the coatings significantly
Mechanical and metallurgical properties of two-layered diamalloy 4010 and 2002 HVOF coating
No full textDiamalloy 4010, which is iron/molybdenum blend, is resistive to wear and Diamalloy 2002 is resistive to corrosion and wear. However, combination of these powders in layered structure, may offer advantages over the individual powders. In this case, mechanical properties of the resulting layered structure could be improved. Consequently, investigation into mechanical and metallurgical properties of the resulting structure is necessary. High Velocity Oxy-Fuel coating of Diamalloy 2002 [(WC12Co)50,Ni33Cr9Fe3.5Si2B2C0.5] powders and Diamalloy 4010 [Fe68Mo30Cr1.8Mn0.2] powders as well as two-layered coatings consisting of these powders was carried out. In the two-layered structure, Diamalloy 4010 was sprayed at the substrate surface while Diamalloy 2002 was sprayed on the top of Diamalloy 4010 coating. The coating microstructure and morphology were examined using optical microscope, Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS). The indentation tests were carried out to evaluate the microhardness and surface elastic modulus of the resulting coatings. The mechanical properties of the coatings were examined through tensile and three-point bending tests. It was found that the coating produced for Diamalloy 2002 resulted in higher hardness than that corresponding to Diamalloy 4010. The failure mechanism of coating during tensile and three-point bending tests was mainly crack formation and propagation in the coating. The elastic modulus of coating produced from Diamalloy 2002 was higher than that of Diamalloy 4010 coating, which was due to the presence of 12% WC in the coating. The irregularities observed in the elastic limit of the curves indicated the formation of cracks in the coatings, which was particularly true for two layered coating. The shear stress developed at interface of the two-layered coating was responsible for the crack initiation in the coating. The deep cracks were also formed in the coatings after the tensile tests. This was attributed to the local stress centers, which increased the stress intensity under the tensile load
Risk factors for postoperative bile leakage: a retrospective single-center analysis of 411 hepatectomies
No full textBACKGROUND: The primary focus of the study was to analyze the risk factors for bile leakage after hepatectomy for benign or malignant tumors. METHODS: A total of 411 patients who had undergone hepatectomy between December 2006 and December 2011 were retrospectively analyzed. The severity of bile leakage was graded according to the ISGLS classification. Twenty-eight pre- and postoperative parameters were analyzed. RESULTS: The overall bile leakage incidence was 10.2% (42/411). The severity of the leakage was classified according to the ISGLS classification. Bile leakage was detected early in case of abdominal drainage (11.4% vs 1.9%, P=0.034). It prolonged the time of hospitalization (16 vs 9 days, P=0.001). In all patients, wedge resection was associated with a higher incidence of bile leakage in contrast to anatomical resections (25.6% vs 4.1%, P<0.0001) regardless of the underlying liver disease. Furthermore, total vascular exclusion increased risk of bile leakage (P=0.008). CONCLUSIONS: Bile leakage as a major issue after hepatic resection is related to the postoperative morbidity and the hospitalization time. It is associated with non-anatomical resection and a total vascular exclusion
Investigation into laser re-melting of inconel 625 HVOF coating blended with WC
No full textHigh velocity oxy-fuel (HVOF) spraying of Diamalloy 1005 powders mixed with WC particles onto steel (304) is considered and laser re-melting of the resulting coatings is examined. Laser re-melting process is modeled to determine the melt layer thickness while temperature increase is formulated using the Fourier heating law. The morphological and metallurgical analyses prior and post laser re-melting process are carried out using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). X-ray diffraction (XRD) technique is used to determine the residual stress developed in the coating while the analytical formulation is adopted to predict the residual stress levels at the coating base material interface. The indentation tests are carried out to determine the Young’s modulus and fracture toughness of the coating prior to laser re-melting. Corrosion resistance of coating is measured using potentiodynamic polarization technique prior and post laser treatment process. The predictions of the melt layer thickness are in good agreement with experimental results. The presence of WC particles modifies temperature rise and its gradient in the coating while affecting the Young’s modulus, residual stress levels, and fracture toughness of the coating. The differences in the thermal properties of Inconel 625 powders and WC particles result in formation of small size cellular structure through polyphase solidification. WC dissolution in the central region of the large polycrystalline cells is observed due to the loss of carbon through carbonic gas formation. The results of corrosion tests prevail that significant improvement of corrosion resistance can be achieved after laser treatment process
Incretins, pregnancy, and gestational diabetes
No full textThe number of pregnant women affected by gestational diabetes mellitus (GDM) is increasing among Caucasians, and East Asians. GDM also increases the risk for later advent of type 2 diabetes mellitus (T2DM), obesity, and cardiovascular disease in both women and their offspring. The underlying mechanism of GDM is not fully elucidated. Incretins such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), have been suggested to have a role in maternal metabolism and weight as well as fetal growth. These hormones might be implicated in mechanisms that compensate for the increment in glycemia and insulin resistance seen during pregnancy, while other factors, such as heredity, environment and lifestyle, but also different race/ethnic background might also lead to the comorbid health problems. Some studies indicate that pregnancy is associated with a diminished GLP-1 response which is more prominently evident in women with GDM and normalizes after delivery. Postprandial GIP level seems to be unaffected by pregnancy, despite its increased level in GDM. On the other hand, the reduced incretin effect observed in GDM may represent a risk factor for obesity, T2DM and metabolic disorders even in the offspring of these women. Further investigations are needed to establish the exact role of incretins in pregnancy and gestational glucose intolerance
- …
