Experimental study of the strength characteristics of fixation of the symphysis pubis with an original plate for the reconstruction of the anterior pelvic semi-ring

The destabilization of bone fixators has led to repeated surgical interventions that increased the risk of migrations of metal fixators, infectious and inflammatory complications as well. The modern trends in hip bone injury surgery are related to developing and using of metal fixators, which are effective in acute injury; however, sometimes the condition of the patient and the technical support of hospitals don’t allow performing surgery in the acute period, and these metal fixators are ineffective for chronic damage. Consequently, until now, the problem of finding the optimal design of structures for fixing chronic damage of anterior pelvic semi-ring which will be able to exclude its destabilization, is still of current interest.The purpose of the study: developing and experimental researching of durable features of original plate for reconstruction of the anterior pelvic semi-ring.Materials and methods: In order to ensure stable fixation of chronic pelvic injuries, the original metal plates have been worked out. They are made individually in accordance with the anatomical and functional structures of the anterior pelvic semi-ring of the patient with using additive technologies. The study of the reliability of the different variants of ostiosynthesis of the anterior pelvic semi-ring with using well-known pelvic plates and a new original design was carried out. Stability tests for different plate fixing methods and mechanical strength of metallophyxators were carried out on a universal test machine of LFM-50kN series.Results: one plate fixation in tensile test showed the lowest result – 0.341 kN, a low result of shear loads was received with the same object. The best result was shown by the polyaxial monolithic plate fixation in case of stretching – 0.51 kN at the shear loads – 0.591 kN. Necessary force applied to destabilizing of the metal structure while using a polyaxial monolithic plate was a half-higher than stretched, and a third higher than at shear loads, it demonstrates the benefits of using these metal fixators.Conclusion: It is experimentally confirmed that the polyaxial monolithic plate provides the highest stability of fixing anterior pelvic semi-ring indicator in contrast with fixing of one or two plates.

Enhancing Turbine Deposition Prediction Capability With Conjugate Mesh Morphing

A framework for performing mesh morphing in a conjugate simulation in the commercial Computational Fluid Dynamics (CFD) software ANSYS Fluent is presented and validated. A procedure for morphing both the fluid and solid domains to simulate the protrusion of deposit into the fluid while concurrently altering and adding to the solid regions is detailed. The ability to delineate between the original metal sections of the solid and the morphed regions which represent deposit characteristics is demonstrated. The validity and predictive capability of the process is tested through simulation of a canonical impingement jet. A single over-sized impingement jet (6.35 mm) at 894 K and an average flow velocity of 56.5 m/s is used to heat a nickel-alloy target plate. One gram of 0-5 μm Arizona Road Dust (ARD) is delivered to the target and a Particle Shadow Velocimetry (PSV) technique is used to capture the transient growth of the deposit structure on the target. Thermal infrared images are taken on the backside of the target and synchronized with the PSV images. The experiment is modeled computationally using the Fluent Discrete Phase Model (DPM) and the Ohio State University (OSU) Deposition Model for sticking prediction. The target is morphed according to the particulate volume prediction. The deposit regions are assigned an effective conductivity (keff) representative of porous deposit, and the fluid and thermal computations are reconverged. 10 mesh morphing iterations are performed accounting for the first half of the experiment. The morphed deposit volume and height are compared to the experiment and show reasonable agreement. The backside target temperatures are also compared, and the simulations show the ability to predict the reduction in temperature that occurs as the growing deposit insulates the metal surface. It is demonstrated that the assignment of unique thermal conductivities to the deposit and metal cells within the solid is critical. With a more robust and accurate implementation of the deposit keff, this conjugate mesh morphing framework shows potential as a tool for predicting the thermal impact of deposition.

Transmittance enhancement at Graphene/Al interfaces

When two metal films stack together forming “hetero-film”, it has been generally accepted that effective transparency is lower than the respective metal film as a result of the absorption accumulation. Here, we report a counterintuitive phenomenon where transparency of a hetero-film is significantly higher compared to the original metal film1. Specifically, we found that by layering one-atom-thick graphene on an aluminum (Al) film, the transparency of the Al film is dramatically increased from ~60% to 80% under 550 nm wavelength light. Due to the counter-intuitive observation, we anticipate this work will benefit the community in fundamental understanding and reliable utilization of graphene and Al interactions.

Ethylenediamine loading into a manganese-based metal–organic framework enhances water stability and carbon dioxide uptake of the framework

Metal–organic frameworks (MOFs) based on 2,5-dihydroxyterepthalic acid (DOBDC) as the linker show very high CO 2 uptake capacities at low to moderate CO 2 pressures; however, these MOFs often require expensive solvent for synthesis and are difficult to regenerate. We have synthesized a Mn-DOBDC MOF and modified it to introduce amine groups into the structure by functionalizing its metal coordination sites with ethylenediamine (EDA). Repeat framework synthesis was then also successfully performed using recycled dimethylformamide (DMF) solvent. Characterization by elemental analysis, FTIR and thermogravimetric studies suggest that EDA molecules are successfully substituting the original metal-bound DMF. This modification not only enhances the material's carbon dioxide sorption capacity, increasing stability to repeated CO 2 sorption cycles, but also improves the framework's stability to moisture. Moreover, this is one of the first amine-modified MOFs that can demonstrably be synthesized using recycled solvent, potentially reducing the future costs of production at larger scales.

Hydrogen-Bond-Promoted Metal-Free Hydroamination of Alkynes

An original metal-free regio- and stereoselective intermolecular hydroamination of alkynes is described. Various (E)-enamines were obtained from arylacetylenes and aliphatic secondary amines in the presence of ethylene glycol as a solvent. The latter is assumed to play a major role in the mechanism through hydrogen bonding and proton exchange.

THE INFLUENCE OF LASER PEENING PULSE NUMBER ON HARDNESS, RESIDUAL STRESS AND ADHESIVE WEAR OF AISI 316l STAINLESS STEEL

Improvement of Wear adhesive properties using laser peening treatment at varied number ofpulse of Austenitic stainless 316L is studied. According to typical ASTM G99-05 number ofwear inspection test are prepared in dimensions 20x10 mm then compiled into four groups.The surface test of three groups is exposed to a number of laser pulse 1, 2, 4 pulsesrespectively by laser peening without coating. Microstructure, residual stress, hardness, istested. Wear test using pin on disc method are used on all groups of specimens at twoparameters, diverse times 10 ,20,30 min with constant load 1kg , and divers load 1,1.5, 2kg with constant time 10 min. from results it was concluded that decrease in hardness andrises in ductility shared to increases in wear properties for the original metal and leaserpeening participated to rise in the wear resistance due to increase in hardness , compressionresidual stress and the heterogeneity of the evidence in the microstructure ,four pulse laserpeening give the lowest wear rate comparing with one pulse which witness decreases inwear rate.

IM PROVEMENT OF MECHANICAL PROPERTIES OF ALUMINUM ALLOY 6061 –T6 WELD JOINT USING DC PULSED GAS TUNGSTEN ARC WELDING (PGTAW)

The effect of DC pulsed GTAW method factors on mechanical properties of Aluminumalloys 6061–T6 is proves. Throbbed GTAW on the sheet having dimension of (200* 100*5mm) is implemented at variable pulse current (150, 160, 170, 190) and constant frequencyto get numerous connected joints by electrode type" ER4043 (Al Si5) as a padding metallicand argon as protective gas and compared with base current GTAW welding at D C currentat 90 amps. The welded pieces are examined by X-ray radiography. The welded joints weretreated by heat, the joints heated for half an hour in the furnace to 150 C° then cooled in theair to release the residual stresses. Mechanical quality of the weld joints. Microstructuralcategorizations, Micro hardness, enduring stress are examined. Consequences exposed thata common decline of mechanical properties of TIG welded joints conveyed 34% analogieswith parent metal while the PGTAW joined offers better mechanical qualities analogy withof TIG joined in reductions conveyed 8.4% analogies with original metal this is because ofthe microstructure variations through the joining method and compressive residual stressgeneration in the weld zones. It has been found that by PGTAW improved the mechanicalproperties of welded joints which rely on current parameters.

Using three-dimensional rapid prototyping in the design and development of orthopaedic screws in standardised pull-out tests

The majority of orthopaedic screws are designed, tested and manufactured by existing orthopaedics companies and are predominantly developed with healthy bone in mind. The timescales and costs involved in the development of a new screw design, for example, for osteoporotic bone, are high. In this study, standard wood screws were used to analyse the concept of using three-dimensional printing, or rapid prototyping, as a viable stage of development in the design of a new bone screw. Six wood screws were reverse engineered and printed in polymeric material using stereolithography. Three of the designs were also printed in Ti6Al4V using direct metal laser sintering; however, these were not of sufficient quality to test further. Both the original metal screws (metal) and polymeric rapid prototyping screws were then tested using standard pull-out tests from low-density polyurethane blocks (Sawbones). Results showed the highest pull-out strengths for screws with the longest thread length and the smallest inner diameter. Of the six screw designs tested, five showed no more than a 17% variance between the metal and rapid prototyping results. A similar pattern of results was shown between the screw designs for both the metal and rapid prototyping screws in five of the six cases. While not producing fully comparable pull-out results to orthopaedic screws, the results from this study do provide evidence of the potential usefulness and cost-effectiveness of rapid prototyping in the early stages of design and testing of orthopaedic screws.

The use of rapid prototyping in the joining of fractured historical silver object

Purpose This paper aims to present a proposal for the restoration of a silver crown by means of fitting pieces produced by the process of 3D modelling and rapid prototyping. It also analyses the benefits of this procedure in restoration of objects weakened by corrosive processes. Design/methodology/approach Elemental chemical analysis was carried out in the alloy used in the manufacture of the crown and the constructive and corrosive processes present were studied. Three fitting pieces were modelled and prototyped in wax casting by the stereolithography apparatus system aiming to restore the part and protect the original metal against impacts and external tensions which could speed up some deterioration processes. Findings The procedure presented in this paper has shown that formal and dimensional accuracy, only achieved by means of 3D technologies, made the restoration and mechanical stability of the crown possible without the use of adhesives or welding. Originality/value The proposed procedure is a new restoration alternative which causes minimal impact to the object and abides by the main standards for modern conservation. It is made with metal which is compatible with the original piece, retractable and easily identifiable.

A rechargeable metal-free full-liquid sulfur–bromine battery for sustainable energy storage

We report an original metal-free full-liquid battery depending on the reversible conversion chemistry between sulfur species and flexible redox-active couples with highly positive potential, for example, Br3−/Br−.