Silver Nano-Coating of Liquid Wood for Nanocomposite Manufacturing

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Cavitation Erosion Tests Performed by Indirect Vibratory Method on Stainless Steel Welded Samples with Hardened Surface

The paper presents the results of cavitation erosion tests performed on two types of samples. The materials of the samples are frequently used for manufacturing and repairs of the hydro turbines components submitted to cavitation. The first sample was made by welding of an austenitic stainless steel on austenito-feritic base material. The second sample was made similarly with the first but with a martensitic base material. After the welding processes, on both samples was applied a hardening treatment by surface peening. The cavitation erosion tests were performed on vibratory equipment using the indirect method with stationary specimen. The results show a good cavitation erosion resistance on both samples

Additive manufacturing of composite materials by FDM technology: A review

The additive manufacturing known also as ―3D printing‖ or ―rapid prototyping‖ is a present manufacturing method (compared to classic manufacturing methods) where layers of material are deposited at a time (successively) until a finished product is obtained. Depending on the phenomenon, material (in solid, liquid or powder state) used by the 3D printing equipment, a solid part, can be achieved using processes as: binder jetting,extrusion, material jetting, direct energy, vat photo-polymerization and powder bed fusion. In the present paper, we have summarized some knowledge regarding the 3D printing technologies, fused deposition modeling (FDM) prototyping method, and different types of test regarding PLA material properties (tensile test, flexural test). The FDM technology has registered benefits as cost, product quality, functionality and manufacturing time, continuously optimized and adopted by more and more companies, research institutes and consumers

Additive manufacturing of composite materials by FDM technology: A review

179-192The additive manufacturing known also as “3D printing” or “rapid prototyping” is a present manufacturing method (compared to classic manufacturing methods) where layers of material are deposited at a time (successively) until a finished product is obtained. Depending on the phenomenon, material (in solid, liquid or powder state) used by the 3D printing equipment, a solid part, can be achieved using processes as: binder jetting,extrusion, material jetting, direct energy, vat photo-polymerization and powder bed fusion. In the present paper, we have summarized some knowledge regarding the 3D printing technologies, fused deposition modeling (FDM) prototyping method, and different types of test regarding PLA material properties (tensile test, flexural test). The FDM technology has registered benefits as cost, product quality, functionality and manufacturing time, continuously optimized and adopted by more and more companies, research institutes and consumers

When myocardial infarction is choosing young victims

We present the case of a 31-year-old patient, without cardiovascular risk factors, without significant pathological or family history of cardiovascular disease, who was diagnosed with severe coronary artery disease, left main bifurcation localization, which required surgical coronary revascularization. The angiographic and intraoperative aspect excluded the most common causes of non-atherosclerotic causes of coronary lesions. Vasculitis was another possible etiology but was also excluded based on the normal clinical examination, negative inflammation markers, lack of diffuse vascular impairment, TPHA and negative VDRL. Prolonged mental stress can lead to accelerated progression of atherosclerosis by inducing endothelial dysfunction, our patient describing a “burnout syndrome” in the last few months. The particularity of the presented case is the severe coronary artery disease in a young patient without discovering the main etiology of the advanced atherosclerotic process

EURONEAR - Recovery, Follow-up and Discovery of NEAs and MBAs using Large Field 1-2m Telescopes

We report on the follow-up and recovery of 100 program NEAs, PHAs and VIs using the ESO/MPG 2.2m, Swope 1m and INT 2.5m telescopes equipped with large field cameras. The 127 fields observed during 11 nights covered 29 square degrees. Using these data, we present the incidental survey work which includes 558 known MBAs and 628 unknown moving objects mostly consistent with MBAs from which 58 objects became official discoveries. We planned the runs using six criteria and four servers which focus mostly on faint and poorly observed objects in need of confirmation, follow-up and recovery. We followed 62 faint NEAs within one month after discovery and we recovered 10 faint NEAs having big uncertainties at their second or later opposition. Using the INT we eliminated 4 PHA candidates and VIs. We observed in total 1,286 moving objects and we reported more than 10,000 positions. All data were reduced by the members of our network in a team effort, and reported promptly to the MPC. The positions of the program NEAs were published in 27 MPC and MPEC references and used to improve their orbits. The O-C residuals for known MBAs and program NEAs are smallest for the ESO/MPG and Swope and about four times larger for the INT whose field is more distorted. The incidental survey allowed us to study statistics of the MBA and NEA populations observable today with 1--2m facilities. We calculate preliminary orbits for all unknown objects, classifying them as official discoveries, later identifications and unknown outstanding objects. The orbital elements a, e, i calculated by FIND_ORB software for the official discoveries and later identified objects are very similar with the published elements which take into account longer observational arcs; thus preliminary orbits were used in statistics for the whole unknown dataset. (CONTINUED)Comment: Accepted in Planetary and Space Science (Aug 2011

Microstructure, mechanical properties and technology of samples obtained by injection from arboblend V2 nature

272-276In all the activity areas, the use of recycled materials has become an important trend. From this point of view, the liquid wood is the material that will replace plastic in the near future. There are three types of liquid wood as follow: arbofill, arboblend and arboform. Liquid wood can be reused up to five times over, without affecting the mechanical properties of the material, as for example fire resistance and durability. The liquid wood has a positive impact over the environment compared to petroleum-derived plastics.  In this paper, arboblend V2 nature is used. Experimental data show that the tensile strength reached 44.05 ± 0.48 MPa at 23°C and the material had a brittle behavior. The results obtained are better than PE-40 MPa, PVDF (poly vinylidene fluoride)-43 MPa, PCTFE (ethylene copolymer)-32 MPa. The friction coefficient registers a slight decrease approximately in the first 25 s and then throughout the completely tested period it registers a slight increase. The friction coefficient average using the disc rotating is 0.1627. Variation of friction coefficient is similar, the average friction coefficient being 0.1376. The results obtained are better than PA 12-(0.32-0.38); PP-0.3; PE-HD (high density polyethylene)-0.29; ABS- 0.5; PVDF (poly vinylidene fluoride)-0.23. Arboblend V2 nature seems to have a structure between amorphous and crystalline. <span style="color:black; mso-ansi-language:EN" lang="EN">Using software of machine equipment is determined the following phases with peaks<span style="color:black; mso-ansi-language:EN" lang="EN"> highlighted, such as C14H26CuO12S2 with monoclinic <span style="color:black; mso-ansi-language:EN" lang="EN">crystal structure and another one with <span style="color:black; mso-ansi-language:EN" lang="EN">unknown crystal structure. The SEM analysis shows a uniform structure with small impurities with a random orientation. In the spectrum of chemical elements dominate, in percentage and atomic mass, carbon and oxygen followed by nitogen. According to the analyses performed and to the conclusions drawn, the arboblend V2 nature can replace the plastic materials in many industrial applications, such as the automobile industry, furniture industry, toys industry, electrical industry, computers, mobile phone, housing etc. </span

Study of microindentation and differential scanning calorimetry of reinforced polyamide

333-340Polyamides comprise the largest family of plastics engineering with a very wide range of applications in many fields of activities. Characteristically polyamides are resistant to wear and abrasion, have good mechanical properties even at elevated temperatures, low permeability to gases and good chemical resistance. Samples are obtained by monocomponent injection using Taguchi experimental plan with six input factors and two levels of variation for each of them. The considered parameters inside the experiment are mold temperature, melt temperature, injection pressure, injection speed, cooling time (in mold) and injection time. This study presents some aspects of microindentation and differential scanning calorimetry for polyamide with 30% fiberglass and microsphere reinforcement. For microindentation experimental study, UMT-2 universal equipment (CETR-Center of Trybology, INC. USA) is used. It was also used a sensor by 2 kg, a maximum force of 15 N and indenter radius Rockwell type with diamond peak is 200 μm. The software package used indicates microhardness values and indentation reduced modulus and Young's modulus and it generates experiment graphs. Concerning the differential scanning calorimetry the experiments were performed on differential scanning calorimeter (DSC) type F3 Maia (supplied by Netzsch) in argon protective atmosphere. The temperature difference between sample and reference is measured and recorded as heat flow. Temperature is measured using three thermocouples, one indicating the sample temperature, the temperature set point second and final furnace temperature. DSC thermograms evaluation will be done with PROTEUS software. To determine the critical points of transformation, transformation starting temperature (onset), temperature when 50% of the change occurred (peak) and finally the transformation temperature (end) and will use the tangent method. The amount of heat dissipated (in the case of endothermic transformation)/absorbed (in the case of exothermic transformation) will be determined using a sigmoidal baseline (ΔH area)

Study of microstructure and mechanical properties of injection molded Arboform parts

534-540The industry of petroleum-based plastic materials is one of the major responsible for numerous unpleasant environmental impacts. The biggest negative effect is given by absence of plastics biodegradability and recyclability, leading to accumulation of huge amount of waste. The experimental study is planed over the Taguchi methodology with two levels and six input parameters. Experimental data show that the tensile strength reached 58.61±2.73 MPa at 23oC and 5.45±0.34 MPa at 60oC. The friction coefficient exhibits a slight decrease during the first 100 s, in case of disk rotation, and then the value is stable throughout the whole testing. Considering disk oscillation, there is an increase in the friction coefficient, which reaches a peak after about 50 s and then decreases within the range of 50-150 s. The material seems to have a completely amorphous structure, without being able to accurately determine the type of existing constituents. It includes C, O and other accompanying elements in very small proportions. The SEM analysis shows a randomly oriented structure. In the chemical elements spectrum, carbon and oxygen predominate, in both percentage and atomic mass. According to the analyses performed Arboform L, V3 Nature can replace plastic materials in many industries, such as automotive, toys, construction, electrical, computers, mobile phone cases, etc. </span