Study on preparation process parameters and tribological properties of porous PI materials

Purpose Previously, the effect of pore-forming agents on the properties of pore size and morphology was studied. In this paper, we determine the optimal combination of parameters by tensile strength and perform tribological tests with optimal combination of parameters. Design/methodology/approach In this paper, porous polyimide (PI) materials were fabricated using vacuum hot molding technology. The orthogonal experiment was designed to test the mechanical properties of porous PI materials with the process parameters and the content of pore-forming agent as the changing factors. The porous PI oil-bearing materials were obtained by vacuum immersion, and tribological test were carried out. Findings The results showed that porous PI oil-bearing materials are suitable for low-speed and low-load conditions. The actual value of the friction coefficient basically match with the theoretical value of the regression analysis, and the errors of the friction coefficient are within 10% and 3%, respectively, which proves that the method used in the study is feasible for the friction coefficient prediction. Originality/value In this paper, we have produced a new porous oil-bearing material with good tribological properties. This study can effectively predict the friction coefficient of PI porous material.

Fundamental Investigation for Processing of Pb-Cu-S-Bearing Materials

The processing of polymetallic materials provides some challenges to every flowsheet. Within Aurubis Cu-Pb-metallurgical flowsheet, a broad range of raw materials and intermediates are processed. Continuous improvements are required to adapt the flowsheet according to the changing material quantity and quality. Therefore, thermodynamic modeling is the desired and most efficient way to conduct scenario analysis. Hence, databases and software are becoming better and better as the acceptance of this method increased. Further understanding is promoted by conducting experimental test work to validate the calculated results. In this research work, the impact of various oxygen potential on the formation of the condensed phases’ slag, matte, speiss and crude lead were investigated. A frequent check of slag metallurgy, in particular, the iron and lead concentration, provide feedback if the metallurgical process is operating at the right oxygen potential. Following, the calculated distribution coefficients for Cu, Pb, As, Sb, Sn and Ni between matte/speiss and speiss/lead are discussed.

Microstructure Evolution of AlSn20Cu Alloy Prepared by Conventional Casting and Semi Continuous Casting during Rolling and Annealing

AlSn20Cu alloy is currently one of the most widely used bearing materials, and its microstructure is the most important indicator in application. In this paper, AlSn20Cu alloy ingots were prepared by two methods: ordinary casting and semi-continuous casting, and deformation and annealing process of the two ingots were studied. Scanning electron microscope (SEM) and Image Pro Plus software were used to observe and analyze the evolution of the microstructure, and the morphological information such as the average grain size and area fraction of the Sn phase was quantitatively characterized. The effects of casting method, deformation temperature, deformation amount and annealing temperature on the morphology of Sn phase were studied in this paper. Compared with ordinary casting, the cooling rate of semi-continuous casting is higher, so the Sn phase is smaller, the casting defects are less, and the deformability of the alloy is better. The AlSn20Cu alloy prepared by ordinary casting has better deformability at about 140 °C, while the AlSn20Cu alloy prepared by semi-continuous casting can be rolled and deformed at room temperature. When the deformation is greater than 40%, after annealing at 250 °C, the average grain size of the Sn phase in the AlSn20Cu alloy prepared by semi-continuous casting is around one hundred square microns and the area fraction is more than 10%, and the Sn phase morphology is better than ordinary casting alloy under any processing conditions.

The development of an intellectual property strategy for a biotechnology company

<p>The 2014 Masters of Advanced Technology Enterprise (MATE) programme is a multi-disciplinary course with the goal of creating teams that explore the challenges of creating successful technology enterprises. NacreTech is the result of one of the enterprises which has been developed within this course. It has found a market application for a nacre-like material as a biodegradable osteoconductive load bearing materials for orthopaedic implants and developed a target product profile to help guide further material development to out-compete existing materials on the market. In addition a proof of concept testing plan, intellectual property strategy and regulatory analysis has been conducted. This thesis is based on the author’s experience working within NacreTech while applying current knowledge and thinking surrounding protecting intellectual property for biotechnology. In particular, the author has investigated the intellectual property aspects, such as the requirements of the complete specification, filing dates and locations, and existing strategy models, required for commercialisation of the NacreTech biomaterial and examines the factors which influenced the development of the intellectual strategy.</p>

The development of an intellectual property strategy for a biotechnology company

<p>The 2014 Masters of Advanced Technology Enterprise (MATE) programme is a multi-disciplinary course with the goal of creating teams that explore the challenges of creating successful technology enterprises. NacreTech is the result of one of the enterprises which has been developed within this course. It has found a market application for a nacre-like material as a biodegradable osteoconductive load bearing materials for orthopaedic implants and developed a target product profile to help guide further material development to out-compete existing materials on the market. In addition a proof of concept testing plan, intellectual property strategy and regulatory analysis has been conducted. This thesis is based on the author’s experience working within NacreTech while applying current knowledge and thinking surrounding protecting intellectual property for biotechnology. In particular, the author has investigated the intellectual property aspects, such as the requirements of the complete specification, filing dates and locations, and existing strategy models, required for commercialisation of the NacreTech biomaterial and examines the factors which influenced the development of the intellectual strategy.</p>

Science literacy-based sound wave e-worksheet: Validity aspects

This study aims to describe the validity of e-worksheets based on science literacy in sound-bearing materials. This research is research and development with the ADDIE model. This science literacy-based e-worksheet validator numbers three people, consisting of two academics and one practitioner. The validation results using an e-worksheet validation sheet based on science literacy show that the validity of e-worksheets in sound wave material has good criteria. Therefore, e-worksheets based on science literacy can be used to learn physics in sound wave material.

Refining of Precious Metal Bearing Materials from Secondary Sources-Methanesulfonic Acid Leaching of Raw Silver Granules as a Promising Approach towards a Green Way of Silver Refining

The state-of-the-art technology of raw silver refining in a silver nitrate-based electrorefining process (Moebius-electrolysis) is accompanied by several disadvantages, both from a technological and from an ecological point of view. In addition, increasing concentrations of critical impurities from secondary sources, like palladium, in raw silver are a further challenge for the future of silver refining. Thus, there is strong motivation for the development of an adequate, alternative process of raw silver refining to substitute the existing Moebius-electrolysis. Due to its less environmentally toxic character and the high aqueous solubility of its silver salt, methanesulfonic acid (MSA) is a possible base chemical for the design of an efficient refining method based on leaching of raw silver followed by electrowinning, with less ecological and technological complications. In this paper the results of some fundamental investigations on the leaching of raw silver granules, containing approx. 94% silver, with methanesulfonic acid and hydrogen peroxide as an oxidation agent are presented. Agitation leaching experiments were conducted on a laboratory scale and the effects of the solid concentration, the hydrogen peroxide dosage and the temperature as leaching parameters were studied. The obtained results indicate that silver leaching yields of more than 90% are achievable with leaching at elevated temperatures of 65 °C or 80 °C, solid concentrations of 500 g/L and at a stoichiometric H2O2:Ag-ratio of 3:1. Increased solid concentrations greater than 500 g/L and elevated temperatures of 65 °C or 80 °C additionally improved the selectivity of the process regarding the leaching of Pd.

FRESH METHOD: 3D BIOPRINTING AS A NEW APPROACH FOR TISSUE AND ORGAN REGENERATION

Over the last decade, techniques of additive manufacturing of biomaterials have undergone a transformation, from a fast prototype tool used in research and development, to a viable approach in the production of customised medical devices. The key to this transformation is the ability of additive manufacturing to precisely define the structure and properties of a material in three dimensions, and to adjust those properties to unique anatomical and physiological criteria based on the medical data obtained by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). The 3D bioprinting technique was developed as a solution to provide temporary and ubiquitous support of structures during the printing process. In general, integrated 3D printing may be understood as a building chamber that is filled with bearing materials, where biomaterials, cellular spheroids, cell-laden hydrogels and other materials (bioinks) are deposited using a syringe-based extruder. In particular, FRESH 3D bioprinting is a revolutionary technology, which may bring a fast and efficient advancement to medicine thanks to the ability to print new tissues from live cells.

Investigation of the possibility of improving the performance of rolling bearings using metal-coating nanotechnologies

Проведены исследования по повышению износостойкости трущихся деталей подшипника качения за счет использования металлоплакирующих нанотехнологий в процессе обкатки и эксплуатации. Приведены результаты лабораторных триботехнических испытаний подшипниковых материалов в режиме металлоплакирования. Показан механизм образования защитной пленки на стальной поверхности деталей подшипника качения. Экспериментальным путем подтверждена возможность увеличения ресурса подшипников качения в процессе эксплуатации. Studies have been carried out to increase the wear resistance of the friction parts of the rolling bearing due to the use of metal-coating nanotechnologies in the process of running-in and operation. The results of laboratory tribotechnical tests of bearing materials in the metal plating mode are presented. The mechanism of formation of a protective film on the steel surface of rolling bearing parts is shown. The possibility of increasing the service life of rolling bearings during operation has been experimentally confirmed.