The influence of the hardening coolant agent on the properties of hot rolled bars of the steel 42CrMo4

In the work the influence results of two different hardening coolant agents on the basic mechanical proprieties and microstructure of the round hot rolled bars were presented. The bars of 42CrMo4 steel were exposed to analysis, and for those bars in the hardening process, water and modern pro-ecological polymer cooling agents Aqua Quench MK were used

A method for the selection of certain force and energy parameters of automatic sheet metal coiling machines

The paper concerns issues related to the sheet coiling process on processing lines. The industry’s needs and requirements for semi-finished products in the form of coil sheets are presented. The paper also discusses the results of the calculations of selected force and energy parameters of devices for coiling sheets made of a zinc-titanium alloy. The presented results were obtained based on calculations and a practical verification of the adopted assumptions using newly-designed devices introduced into operation

Diagnosis of the wear of gears in the gearbox using the wavelet packet transform

The paper presents research aimed at diagnosing early cases of wear of gears tooth surface in the gearbox based on measurements of vibration signals and their processing using the wavelet packet transform. Analysis concerned the vibration signals recorded in a test bench experiment, during which the wear of gears teeth increased (pitting and spalling). The studies allow conclusions to be drawn that the processing of vibration signals using the wavelet packet transform allows the detection of early cases of wear of the working surface of the teeth on the basis of an analysis of selected details of wavelet decomposition and vibration measures

A method for detecting damage to rolling bearings in toothed gears of processing lines

This paper presents a method of diagnosing damage to rolling bearings in toothed gears of processing lines. The research has shown the usefulness of vibration signal measurements performed with a laser vibrometer and of the method of denoising signals by means of a discrete wavelet transform in detecting damage to bearings. The application of the method of analysis of the characteristic frequencies of changes in the vibration signal amplitude made it possible to draw conclusions about the type of damage to the bearings

Efecto de la preparación mediante maceración con enzima asistida comercial sobre el rendimiento, la calidad, y la bioactividad de aceite esencial de residuos de semillas de zanahoria (Daucus carota L.)

Eight enzyme preparations were screened with a view to maximizing the yield of carrot seed essential oil. Three of the eight enzyme preparations investigated, lipase from Mucor circinelloides, XPect® pectinase, and Esperase® protease, significantly influenced the amount of essential oil obtained, with Esperase® being the most effective. The Taguchi method was applied to optimize the processing conditions for the Esperase® protease. Under the optimum conditions, the essential oil yield increased by approximately 48%. The main constituent compounds in the oil are: carotol (OeA: 40.80%–OeB: 46.17%), daucol (OeA: 7.35%–OeB: 6.22%), sabinene (OeA: 5.12%–OeB: 6.13%), alpha-pinene (OeA: 4.24%–OeB: 5.11%) and geranyl acetate (OeA: 4.50%–OeB: 3.68%). As compared to the control sample, the essential oil obtained from enzyme-pretreated carrot seeds has the same biological activity against Bacillus subtilis and Candida sp., lower activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and higher activity against Aspergillus niger and Penicillium expansum.Ocho preparados enzimáticos fueron seleccionados con el fin de maximizar el rendimiento de aceites esenciales de semillas de zanahoria. Tres de los ocho preparados de las enzimas investigadas, lipasa de Mucor circinelloides, Xpect® pectinasa y Esperase® proteasa, influyeron de manera significativa sobre la cantidad de aceite esencial obtenido, siendo Esperase® el más eficaz. El método de Taguchi se aplicó para optimizar las condiciones del procesamiento para esta última. Bajo las condiciones óptimas, el rendimiento de los aceite esenciales aumentó aproximadamente un 48%. Los principales compuestos constituyentes del aceite son: carotol (OEA: 40.80%–OeB: 46,17%), ducol (OEA: 7,35%–OeB: 6,22%), sabineno (OEA: 5,12%–OeB: 6,13%), alfa-pineno (OEA: 4,24%– OeB: 5,11%) y acetato de geranilo (OEA: 4,50%–OeB: 3,68%). En comparación con la muestra control, el aceite esencial obtenido a partir de las semillas de zanahoria mediante enzima-pretratada tiene la misma actividad biológica frente a Bacillus subtilis y Candida sp., menor actividad frente a Staphylococcus aureus, Escherichia coli, y Pseudomonas aeruginosa, y una mayor actividad contra Aspergillus niger y Penicillium expansum

Adding functionality with additive manufacturing : fabrication of titanium-based antibiotic eluting implants

Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p=0.01) improved the compressive strength (5.8±0.7MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6hour period (<28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16μg/mL) and Staphylococcus epidermidis (1μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections