design and control of system for elbow rehabilitation preliminary findings

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Effect of Tool Coating and Cutting Parameters on Surface Roughness and Burr Formation during Micromilling of Inconel 718

Surface roughness and burr formation are among the most important surface quality metrics which determine the quality of the fabricated parts. High precision machined microparts with complex features require micromachining process to achieve the desired yet stringent surface finish and dimensional accuracy. In this research, the effect of cutting speed (m/min), feed rate (µm/tooth), depth of cut (µm) and three types of tool coating (AlTiN, nACo and TiSiN) were analyzed to study their effect on surface roughness and burr formation during the micromachining of Inconel 718. The analysis was carried out using an optical profilometer, scanning electron microscope and statistical technique. Machining tests were performed at low speed with a feed rate (µm/tooth) below the cutting-edge radius for 10 mm cutting length using a carbide tool of 0.5 mm diameter on a CNC milling machine. From this research, it was determined that the depth of cut was the main factor affecting burr formation, while cutting velocity was the main factor affecting the surface roughness. In addition, cutting tool coating did not significantly affect either surface roughness or burr formation due to the difference in coefficient of friction. The types of burr formed during micromilling of Inconel 718 were mainly influenced by the depth of cut and feed rate (µm/tooth) and were not affected by the cutting velocity. It was also concluded that the results for the surface finish at low-speed machining are comparable to that of transition and high-speed machining, while the burr width found during confirmation experiments at low-speed machining was also within an acceptable range

A New Pyrimidine Schiff Base with Selective Activities against Enterococcus faecalis and Gastric Adenocarcinoma

Enterococcus faecalis is known as a significant nosocomial pathogen due to its natural resistance to many antibacterial drugs. Moreover, it was found that E. faecalis infection causes inflammation, production of reactive oxygen species, and DNA damage to human gastric cancer cells, which can induce cancer. In this study, we synthesized and tested the biological activity of a new Schiff base, 5-[(4-ethoxyphenyl)imino]methyl-N-(4-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine (3), and compared its properties with an analogous amine (2). In the biological investigation, 3 was found to have antibacterial activity against E. faecalis 29212 and far better anticancer properties, especially against gastric adenocarcinoma (human Caucasian gastric adenocarcinoma), than 2. In addition, both derivatives were non-toxic to normal cells. It is worth mentioning that 3 could potentially inhibit cancer cell growth by inducing cell apoptosis. The results suggest that the presence of the –C=N– bond in the molecule of 3 increases its activity, indicating that 5-iminomethylpyrimidine could be a potent core for further drug discovery research

Constructing anhydrous halide bridged manganese(II) clusters: Synthesis, structures and magnetic properties

The reaction of Mn0 and HgCl2 with triphenylacetic acid in a mixture of 2-methoxyethanol and toluene afforded complex [Mn2IICl2(O2CCPh3)2(2-methoxyethanol)3] (1) in very good yield. Repeating the same reaction and replacing 2-methoxyethanol with THF forms the complex [Mn3IICl3.04(O2CCPh3)1.96(2-methoxyethanol)(THF)4] (2) in good yield. Furthermore the reaction between Mn0 and triphenylacetic acid in a mixture of THF and toluene after heating produces the complex [Mn4Cl5Na(O2CCPh3)4(THF)6] (3). Finally, the reaction between MnCl2 and potassium triphenylacetate or lithium triphenylacetate in THF and toluene gave complexes [Mn4Cl5K(O2CCPh3)4(THF)6] (4) and [Mn4Cl5Li(O2CCPh3)4(THF)5]·0.75(THF) (5·0.75THF), respectively, in good yields. The crystal structures of 1–5 have been determined by single-crystal X-ray crystallography. Complex 1 is a chloride bridged [MnII2] dimer in which the two metal ions are found in an O5Cl and an O3Cl2 coordination environment. Complex 2 is a trinuclear [MnII3] triangle-like cluster in which the “central” MnII ion is bridged via two chloride ions to the peripheral Mn2+ ions, additionally all manganese ions are connected by oxygen ion in a μ3 mode. Complexes 3–5 are all tetranuclear [MnII4Cl5]3+ metallic clusters displaying similar geometries, in which the tetrametallic core unit possesses a planar square arrangement. DC magnetic susceptibility studies indicate the presence of dominant antiferromagnetic exchange for all 1–4 clusters

Application of Type-2 Fuzzy AHP-ARAS for Selecting Optimal WEDM Parameters

Machining of the nickel-based alloy is very demanding due to its extreme mechanical properties, for example, higher fatigue strength, better corrosion and creep resistance feature, substantial work hardening capability, and appreciable tensile and shear strength. Owing to these properties, the selection of machining parameters is a major challenge for modern machining industries. Therefore, the present experimental work is carried out to select the best parametric combination of the wire electrical discharge machining (WEDM) machine for reducing machining cost and human effort. The Trapezoidal Interval Type-2 fuzzy number (T2FS) integrated Analytical Hierarchy Process (AHP)-based Additive Ratio Assessment (ARAS) method is used for selecting the best WEDM process parameters of Inconel-800 superalloy. Finally, the results were compared with some existing multi-criteria decision-making methods to confirm the validity of the adopted method. The comparison shows that Type-2 Fuzzy AHP-ARAS synergy can help to formulate the problem and facilitate the assessment and ranking of WEDM process parameters when multiple criteria are jointly considered