Design of a compact grinding machine

The availability and cost of tools are among concerns to the public and industries as key operation device used either for commercial or maintenance purposes such precision grinders or polishing machines are usually expensive. Assorted grinding tools in the market differ in terms of cost, required user proficiency levels and have different tool designs that can lead to limitations of flatness of ground surface and significant vibrations with prolonged use. The aim of this study is to develop a design compact grinder that is able to perform precise grinding and polishing while being cost efficient. Both functionality and ergonomic aspects were taken into consideration with market standards derived from datasheets. An initial design of the grinding machine was made using SolidWorks CAD software. A prototype was subsequently constructed and tested by using typical metallurgical sample preparation process with test parameters of grade of grinding paper and usage of lubricant. Microscopic image of ground specimens showed improvement in the quality of grinding with emery paper grades from coarse to fine grits with lubricant during the grinding process. Moreover, the designed compact grinding machine showed better surface finish when compared to using a typical angle grinder on aluminium sample.

Residual Stresses Induced by Surface Working and Their Improvement by Emery Paper Polishing

In many of machine parts and structural components, materials surface would be worked. In this study, residual stresses on the surfaces were measured by X-ray diffraction method, and effects of surface working on the residual stresses were examined. In case of lathe machining of type 304 stainless steel bar, the residual stresses in circumferential directions are tensile, and those in axial directions are almost compressive. Highly tensile residual stresses in the circumferential directions were improved by emery paper polishing. 10 to 20 times of polishing changes high tensile residual stresses to compressive residual stresses. In the case of shot peening on a type 304 stainless steel plate, the compressive residual stress inside is several hundred MPa lower than that on the surface. By applying the emery paper polishing to the shot peened surface 10 or 20 times, the residual stress on the surface is improved to −700 MPa. While fatigue strength at 288 °C in the air of the shot peened material is 30 MPa higher than solution heat treated and electro-polished material, the fatigue strength of the shot peened and followed by emery paper polished material is 60 MPa higher. Thus, the emery paper polishing is simple and a very effective process for improvement of the residual stresses.

Quantitative Analysis of Surface Contouring with Pulsed Bipolar Radiofrequency on Thin Chondromalacic Cartilage

The purpose of this study was to evaluate the quality of surface contouring of chondromalacic cartilage by bipolar radio frequency energy using different treatment patterns in an animal model, as well as examining the impact of the treatment onto chondrocyte viability by two different methods. Our experiments were conducted on 36 fresh osteochondral sections from the tibia plateau of slaughtered 6-month-old pigs, where the thickness of the cartilage is similar to that of human wrist cartilage. An area of 1 cm2 was first treated with emery paper to simulate the chondromalacic cartilage. Then, the treatment with RFE followed in 6 different patterns. The osteochondral sections were assessed for cellular viability (live/dead assay, caspase (cell apoptosis marker) staining, and quantitative analysed images obtained by fluorescent microscopy). For a quantitative characterization of none or treated cartilage surfaces, various roughness parameters were measured using confocal laser scanning microscopy (Olympus LEXT OLS 4000 3D). To describe the roughness, the Root-Mean-Square parameter (Sq) was calculated. A smoothing effect of the cartilage surface was detectable upon each pattern of RFE treatment. The Sq for native cartilage was Sq=3.8±1.1 μm. The best smoothing pattern was seen for two RFE passes and a 2-second pulsed mode (B2p2) with an Sq=27.3±4.9 μm. However, with increased smoothing, an augmentation in chondrocyte death up to 95% was detected. Using bipolar RFE treatment in arthroscopy for small joints like the wrist or MCP joints should be used with caution. In the case of chondroplasty, there is a high chance to destroy the joint cartilage.

Corrosion rate of Al-Si Alloy Reinforced with B4C Nanoparticle prepared by Powder Metallurgy Method using RSM

The current work aims to optimize the Al-Si alloy reinforced with B4C nanoparticles prepared through powder metallurgy technique. The sample was prepared with different weight percentage 0, 4 and 8; the size of the sample was 20 mm x 20mm and sintered in a furnace upto 500oC with argon gas and their by furnace cooled to room temperature. The samples were brushed to remove the slag present in it, and polished by emery paper. Then the samples were weighed in an electric balancing apparatus to measure the initial weight of the sample before dipping it into acid solution. The weight loss was measured to calibrate the corrosion rate of the samples for 9 days. Response surface methodology was designed for three factors at three levels with a response as corrosion rate. The Analysis of Variance (ANOVA) was used to identify the most influencing factor on corrosion rate. The normal probability plot, residual plot, and desirability plot demonstrates the influence of corrosion rate of the composites.

On some variants of figurative compositions in the works of Pyotr Dik

Петр Дик (1939−2002) – всемирно известный художник второй половины XX века, родившийся на Алтае. Его работы хранятся в ведущих музеях России и частных собраниях. Специфической чертой творчества Дика является использование редкой техники – пастель по наждачной бумаге. В данной статье предпринимается попытка выявить в творчестве Дика характерные для художника иконографические мотивы и типы композиций. Pyotr Dik (1939−2002) is the world-famous artist of the second half of the XX century, who was born in Altai. His works are kept in leading Russian museums and private collections. A specific feature of Dik's works is the use of a rare technique − pastel on emery paper. This article attempts to identify iconographic motifs and types of compositions, which were characteristic of the artist's work.

Evaluation of Surface Roughness of 316L Stainless Steel Substrate on Nanohydroxyapatite by Electrophoretic Deposition

The present work was designed on producing nanohydroxyapatite layers using electrophoretic deposition (EPD) on 316L stainless steel substrate. The EPD coatings were prepared by the deposition of hydroxyapatite (HA)-chitosan nanocomposites on different substrate roughness (polish surface, 220 grit SiC grind, and sand blast surfaces). Depositions were performed using the suspensions of HA nano particles (3 g/L) in the mixture of alcohol and distilled water (ethanol, 5 vol. %water and containing 0.5 g/L of chitosan dissolved in 1 vol.% acetic acid. Coatings were achieved on the cathode at constant voltage, time and temperature (90 V, 5 min and 40 °C respectively); the pH value was performed and fitted at 4. After deposition, the coated samples were dried at room temperature for 24 h. The surface topography of coatings was analyzed using atomic force microscopy (AFM). SEM was used to postulate both the surface and the cross section morphology of the coatings. The adhesion bonding between the deposited coatings and substrate were measured using tape tester to evaluate the adhesion bonding between the coating and substrate. The results showed the deposited coatings on sand blasted substrate has less porosity compared with the polish surface and 220 emery paper SiC grinding substrate respectively. The coating on the sand blasted substrate showed higher nanoroughness (122 nm), better adhesion bonding (removal area 15%) and higher thickness layer (12 µm) than that of the polish substrate and 220 emery paper SiC grinding substrate.

Abrasive grit size effect on wear depth of stir cast hybrid Al–Mg–Si composites at high stress condition

The grit size effect on high stress abrasive wear depth of stir cast hybrid self-lubricating Gr/SiC/Al composites was investigated in both as cast (AC) and heat treated (T6) condition. The tests were done at grit size of 100–200 µm, sliding distance of 75 m and applied loads of 5–15 N. The results obtained were differentiated with matrix alloy and SiC/Al composites. At 15 N load, the wear depth of hybrid composites w.r.t. matrix alloy reduced around 19.6% (at 100 µm grit size) and 16.4% (at 200 µm grit size) in AC condition; 26.9% (at 100 µm grit size) and 27% (at 200 µm grit size) in T6 condition. The wear mechanism was analyzed through wear surface analysis of pin and emery paper.

The Tell-Tale Hand: Gothic Narratives and the Brain

The opening story in Winesburg, Ohio (1919) by Sherwood Anderson is called simply “Hands.” It is about a teacher’s remarkable hands that sometimes seem to move independently of his will. This essay explores some of the relevant contexts and potential links, beginning with other representations of teachers’ hands, such as Caravaggio’s St. Matthew and the Angel, early efforts to establish a sign-language for the deaf, and including the Montessori method of teaching children to read and write by tracing the shape of letters with their hands on rough emery paper. The essay then explores filmic hands that betray or work independently of conscious intentions, from Dr Strangelove, Mad Love, to The Beast With Five Fingers. Discussion of the medical literature about the “double” of our hands in the brain, including “phantom hands,” leads on to a series of images that register Rodin’s lifelong fascination with sculpting separate hands.

Computational and Experimental Studies on the Inhibitive Effects of Newbouldia laevis Extract and Magnetic Fields on Copper Corrosion in Aqueous Acidic Media

A ploycrystaline copper (99.99%) coupons of dimension 1x2x5 cm in which a hole of diameter 0.5cm drilled was used. Before all measurements, the coupons were polished successively with metallographic emery paper between (600 and 1200) grits, then washed with doubly distilled water, degreased with acetone and again washed using distilled water and finally allowed to dry in air at room temperature. Explanation of the effects of magnetic fields on inhibition process using the chemical quantum calculations. The dipole moment is the product of a charge and distance of separation of the charges in an atom or molecule. Any process which can cause change in the alignment of the dipoles on the surface of the corroding metal systems can facilitate an increase in inhibition process. The magnetic field acts on the dipoles such that it aligns the charges on the metal thereby providing the needed charge types at the required point. This explains the graph on figure 1 which shows an increase in inhibition efficiency in the presence of magnetic fields.