1,244,361 research outputs found
Development of a virtual reality milling machine for knowledge learning and skill training
Get PDFCurrent 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
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
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
Funerary archaeology in Qatar: old data and new discoveries
No full textThis paper reports preliminary findings from select re-analyses and new excavations conducted under remit of the project ‘Human Populations and Demographics in Qatar from the Neolithic to the Late Iron Age’ (performed in cooperation with Sidra Medicine, the Department of Biology of the University of Rome Tor Vergata, and Qatar Museums Authority). Due to the absence of large settlements, our understanding of pre-Islamic societies in Qatar has until recently been extremely limited. However, progress in bioarchaeological research methods offers new possibilities to address this knowledge gap. Several thousand pre-Islamic burials can now be used as an important resource to elucidate the relationship between population dynamics and socio-cultural changes in pre-Islamic Qatar. In addition to analysis of previously excavated skeletal remains, new excavations can be conducted in carefully chosen cemeteries from different pre-Islamic periods, thereby allowing bioarchaeological samples to be retrieved from undisturbed burial contexts
Mechanical and metallurgical properties of two-layered diamalloy 4010 and 2002 HVOF coating
Get PDFDiamalloy 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
Investigation into coatings produced from nanoparticle blended feedstock for rotating equipment repair applications
Get PDFCoating 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
Investigation into laser re-melting of inconel 625 HVOF coating blended with WC
Get PDFHigh 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
Nutraceuticals as lipid-lowering treatment in pregnancy and their effects on the metabolic syndrome
No full textMaternal nutrition and lifestyle before and during pregnancy influence both mother and offspring’s health and can be correlated with the metabolic syndrome in later life. Findings from animal and human studies indicate that nutrition during pregnancy has an important role in microbiological, metabolic, physiologic and immunologic development and homeostasis. A low nutritional intake in early pregnancy may represent a risk for adverse effects during pregnancy as well as on birth outcome. It seems that dietary supplementation with probiotics in perinatal period may represent safe and practical approach in dealing with the most common adverse pregnancy outcomes such as obesity and gestational diabetes. The SPRING (Study of Probiotics in the prevention of Gestational diabetes) will give important answers about potential benefits of probiotics in pregnant women who are obese and overweight and otherwise at the high risk for complications during pregnancy. Fish oil supplementation during the last trimester of pregnancy showed no effects on plasma lipids and lipoproteins in offspring, as well as on their adiposity. The effect of hypercholesterolemia during pregnancy on both mothers and child needs to be further investigated as it could have a biological role. The guidelines for the eventual clinical approach currently do not exist. Potential benefits of nutraceuticals on several metabolic parameters have been suggested. Limited evidence does not allow to draw final conclusions on preventive health strategies and dietary patterns that should be promoted during pregnancy. Further prospective and intervention studies are needed to establish it. Healthy lifestyle and dietary advice with appropriate supplements usage should be considered
Nutraceuticals as lipid-lowering treatment in pregnancy and their effects on the metabolic syndrome
No full textMaternal nutrition and lifestyle before and during pregnancy influence both mother and offspring’s health and can be correlated with the metabolic syndrome in later life. Findings from animal and human studies indicate that nutrition during pregnancy has an important role in microbiological, metabolic, physiologic and immunologic development and homeostasis. A low nutritional intake in early pregnancy may represent a risk for adverse effects during pregnancy as well as on birth outcome. It seems that dietary supplementation with probiotics in perinatal period may represent safe and practical approach in dealing with the most common adverse pregnancy outcomes such as obesity and gestational diabetes. The SPRING (Study of Probiotics in the prevention of Gestational diabetes) will give important answers about potential benefits of probiotics in pregnant women who are obese and overweight and otherwise at the high risk for complications during pregnancy. Fish oil supplementation during the last trimester of pregnancy showed no effects on plasma lipids and lipoproteins in offspring, as well as on their adiposity. The effect of hypercholesterolemia during pregnancy on both mothers and child needs to be further investigated as it could have a biological role. The guidelines for the eventual clinical approach currently do not exist. Potential benefits of nutraceuticals on several metabolic parameters have been suggested. Limited evidence does not allow to draw final conclusions on preventive health strategies and dietary patterns that should be promoted during pregnancy. Further prospective and intervention studies are needed to establish it. Healthy lifestyle and dietary advice with appropriate supplements usage should be considered
Xenovarta viraktamathi Meshram & Hashmi 2018, sp.nov.
No full textXenovarta viraktamathi sp.nov. (Figs. 1–12) Pale green with red stripes (Figs. 1&2). Vertex lateral margin with a red stripe terminating into two black dot in dorsal view and ventrally with single dot (Fig. 3). Face yellow, anteriorly with boomerang shaped black spot with red margins (Fig. 4). Pronotum anteriorly orange yellow, rest pale green with four red stripes. Scutellum pale with two obscure orange stripes. Front wing pale green with red stripes (Fig. 4). Head including eyes 0.9x width of pronotum, in dorsal view triangularly produced in front; vertex length as long as width across eyes; ocelli near anterior margin of vertex, close to eye; face 1.6x as long as wide; anteclypeus apically exceeding facial margin, slightly wider apically than at base, 0.34 times as long as frontoclypeus (Fig. 4); frontoclypeus parallel sided; clypellus; antennae situated nearly upper margin of eye in facial view (Fig. 3). Pronotum (Fig. 3) 0.73x as wide as long and 0.76x width of scutellum; anterior margin of pronotum roundly produced between eyes. Male genitalia: Pygofer (Fig. 5 & 6) longer than wide, with posterior lobe produced and terminating in dorsally directed acute processes, one on either side. Segment X stout, dorsal half sclerotized, with a caudo-ventral bifid process (Fig. 6). Valve fused to subgenital plates the latter fused to near apex with a poorly developed caudolateral process; with distal macrosetae and many fine ventral setae arranged irregularly (Figs. 9 & 10). Style (Fig. 11) with well-developed preapical lobe, with few short spine-like setae, apophysis digitate 0.23x of the total length. Connective stem as long as arms (Fig. 12), arms closely appressed. Aedeagus (Figs. 7 & 8), with shaft uniform in width throughout length in lateral and ventral view, abruptly tapered distally to acute apex, with pair of lateral subapical lamellate processes; gonopore large, subapical at base of lateral processes; preatrium absent; dorsal apodeme moderately well developed, tapered to narrowly rounded apex. Measurements (mm) - Male: 7.52 long, 1.20 wide across eyes, 0.75 length of pronotum, 1.31 width of pronotum. Type material. Holotype ♂, INDIA: Arunachal Pradesh: Basar (27°59′0″N 94°40′0″E; Altitude- 1896 ft), 30.vi.2018, net sweeping on bamboo plants, coll. Stuti & Tahseen (NPC). Paratypes 2 ♂, same data as holotype (NPC). NCBI GenBank, accession number: MH 986788. Etymology. The species is named after Prof. C. A. Viraktamath in recognition of his monumental contributions to leafhopper taxonomy. Remarks. Xenovarta viraktamathi sp.nov. runs to Xenovarta in Viraktamath’s (2004) key to genera, disagreeing in having a small ventral process on segment X. It also appears to differ from other species of Xenovarta in having the forewing apex rounded rather than truncate. It resembles Xenovarta acuta Viraktamath externally but differs from this and other species by the more rounded apex of the forewing and simple symmetrical aedeagus with a pair of subapical lateral processes.Published as part of Meshram, Naresh M. & Hashmi, Tahseen Raza, 2018, First record of the leafhopper genus Xenovarta Viraktamath (Hemiptera, Cicadellidae, Deltocephalinae) from India with description of a new species, pp. 444-446 in Zootaxa 4532 (3) on page 446, DOI: 10.11646/zootaxa.4532.3.9, http://zenodo.org/record/261552
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