Search results for "mechanic"

Characterization of lignin enforced tannin/furanic foams

2020

Worldwide, tons of lignin is produced annually in pulping plants and it is mainly considered as a waste material. Usually lignin is burned to produce energy for the pulping reactors. The production of value-added materials from renewable materials like lignin, has proved to be challenging. In this study, the effects of addition of three different types of lignin in the production of tannin/furanic foams is investigated. The foams were matured, first at 373 K and finally carbonized at 1073 K and the properties of them including mechanical strength, specific surface area and pore development are investigated before and after thermal treatment. According to the results, higher mechanical stren…

Contributions to risk injury evaluation of human skin contact caused by welding technology in mechanical engineering a company

2017

Assembly by welding is a very important pollutant technological process, mainly of the atmosphere and soil. The formation of gas in welding process is the result of electrodes, fluxes burning, formation of fused bath and welded seam. A large number of human operators feels different adverse effects on health. Most problems appears in respiratory system and include bronchitis, respiratory irritation, fever caused by smoke, changes in lung function, decreased immunity to infection and a possible increase of lung cancer risk. Very little information are available about effects on the organism and skin after exposure to fumes from welding, therefore. In this order, this paper do a risk assessme…

Injury and Throwing Distance in Teenage Cyclist- Vehicle Crash

2016

The study of the injury caused by vehicle-teenage cyclist crash is presented in this paper. The results of the crash with three vehicles: sedan, SUV and Pick up are compared. Three different positions are analyzed: front, rear and lateral position. The injury on the cyclist head is examined by HIC criterion, in the way indicated by the rules. A comparison is done between the results of the simulations for Pick up, SUV and sedan, concluding that the injury of the head is more dangerous for Pick-up impact than SUV or the sedan, but only at greater speed than 40 km/h. Teenage cyclist is more likely to suffer an injury to the chest in rear impacts with the sedan, because 3 ms values remain abov…

Teenage cyclist - Pick up crash by multibody simulation; HIC evaluation and comparison with previous results

2016

The study of the injury caused by Pick-up vehicle-teenage cyclist crash is presented in this paper. The vehicle has high frontal part, in order to compare the results with those obtained previously in the sedan and SUV - teenage cyclist crash. No variation is executed on the model of the teenage cyclist and the bike. Three different positions are analyzed: front, rear and lateral position. The injury on the cyclist head is examined by HIC criterion, in the way indicated in the rules. Correlation HIC – AIS is used to calculate the lethality of the injuries. A comparison is made between the results of the simulations for Pick up, SUV and sedan, concluding that the injury of the head is more d…

Biomechanical comparison between sprint start, sled-pulling and selected squat type exercises

2012

The purpose of the present study was to compare kinetics, kinematics and muscle activity between sprint start, sled-pulling and selected squat type exercises and also to examine how different exercises and variables correlate with the performance time of the block start (10 m). Nine male athletes (4 sprinters, 3 decathlonists, 1 long jumper and 1 triple jumper; mean ± SD; age = 24.9 ± 3.9 yr; height = 180.4 ± 5.9 cm; weight = 80.3 ± 7.5 kg; 100 m record = 11.35 ± 0.29 s) performed measurements and different force-time, electromyographic (EMG) and kinematic variables were compared to sprint start. Most of the comparison was done to the block phase (the phase of force production towards start…

Thermo-Mechanical Behaviour of Flax-Fibre Reinforced Epoxy Laminates for Industrial Applications

2015

The present work describes the experimental mechanical characterisation of a natural flax fibre reinforced epoxy polymer composite. A commercial plain woven quasi-unidirectional flax fabric with spun-twisted yarns is employed in particular, as well as unidirectional composite panels manufactured with three techniques: hand-lay-up, vacuum bagging and resin infusion. The stiffness and strength behaviours are investigated under both monotonic and low-cycle fatigue loadings. The analysed material has, in particular, shown a typical bilinear behaviour under pure traction, with a knee yield point occurring at a rather low stress value, after which the material tensile stiffness is significantly r…

Effect of oil lamination between plasticized starch layers on film properties

2016

International audience; To reduce the hygroscopic character of biodegradable starch-based films, rapeseed oil was incorporated by lamination (starch-oil-starch 3-layers technique). The lipid lamination followed by starch solution casting step induced an emulsion type structure of dried films. Composite films are more opalescent and glossier than fatty free starch films. For all the films, structure is heterogeneous in the cross-section only. Adding fat induced a twice decrease of the tensile strength. Thermal gravimetry analysis did not show differences between films with and without oil. Lipid reduced the moisture absorption particularly at higher RH as well as the surface swelling index, …

Pressure-Dependent Tuning of Photoluminescence and Size Distribution of Carbon Nanodots for Theranostic Anticancer Applications

2020

Carbon nanodots (CDs) have recently attracted attention in the field of nanomedicine because of the biocompatibility, cost-effective nature, high specific surface, good near infrared (NIR) photothermal conversion into heat and tunable fluorescence properties, which have paved the way toward incorporating use of CDs into innovative anticancer theranostic platforms. However, a reliable synthesis of CDs with established and controlled physiochemical proprieties is precluded owing to the lack of full manipulation of thermodynamic parameters during the synthesis, thus limiting their use in real world medical applications. Herein, we developed a robust solvothermal protocol which allow fine contr…

The thermal performances of historic masonry: In-situ measurements of thermal conductance on calcarenite stone walls in Palermo

2018

Abstract Rich literature explores materials and construction techniques of historic buildings, but limited information is available about the thermal and hygrometric features of their envelope. Nevertheless, accurate hygrothermal data are essential for identifying effective energy upgrade measures, which must be compatible with the conservation of the architectural heritage. In order to fill this gap, it is necessary to refer to local contexts, where the variety of historic buildings is limited and their material and construction features are comparable. This paper focuses on historic masonry walls and discusses the results of twenty in-situ measurements of thermal conductance, performed al…

Coherence properties in superconducting flux qubits

The research work discussed in this thesis deals with the study of superconducting Josephson qubits. Superconducting qubits are solid-state artificial atoms which are based on lithographically defined Josephson tunnel junctions properties. When sufficiently cooled, these superconducting devices exhibit quantized states of charge, flux or junction phase depending on their design parameters. This allows to observe coherent evolutions of their states. The results presented can be divided into two parts. In a first part we investigate operations of superconducting qubits based on the quantum coherence in superconducting quantum interference devices (SQUID). We explain experimental data which ha…