Improvements of the MQL Cooling-Lubrication Condition by the Addition of Multilayer Graphene Platelets in Peripheral Grinding of SAE 52100 Steel

In most grinding processes, the use of cutting fluid is required, and research has been carried out to reduce the amount of fluid used due to costs and environmental impacts. However, such a reduction of fluid can result in thermal damage to the machined component because the amount of cutting fluid may not be sufficient to lubricate and cool the system. One way of improving the cutting fluid properties is to add micro or nanoparticles of solid lubricants. This paper aims to evaluate the performance of multilayer graphene platelets dispersed in cutting fluid and applied through the technique of minimum quantity of lubrication (MQL) during the peripheral surface grinding of SAE 52100 hardened steel. In this sense, the influence of these solid particles with respect to the surface and sub-surface integrity of the machined components was analyzed, performing the roughness and microhardness measurement and analyzing the ground surfaces. The results showed that the cooling–lubrication conditions employing graphene could obtain smaller roughness values and decreases of microhardness in relation to the reference value and components with better surface texture compared to the conventional MQL technique without solid particles.

Calculation of the Cutting Forces and Torque when Milling with End Mills

This paper presents a computational sequence for calculating the components of the cutting force and torque when milling with carbide end mills. The calculation algorithm includes the transition from the tangential and radial components of the force to the force components in the machine coordinate system. On the helical cutting edge, two parts are highlighted: one on the cylindrical (peripheral) surface and the other one on the arc of the rounded tip of the tooth. These parts of the cutting edge are divided into sections where the calculation is performed, followed by summation of the force components along the axes of the machine co-ordinate system and the moment relative to the axis of the cutter. An analysis of the components of the force and torque depending on the depth of cutting, feed, number of teeth of the cutter, blade wear and radius of the tip rounding is performed. The ratio of forces and moments for various milling conditions of structural carbon steel and aluminum alloys is shown. The developed algorithm is applied in a computational program that can be used to perform operational calculations of forces and torque for various milling conditions. The calculated parameters can be used as technological limiters in optimization problems, as well as for strength calculations of tools, milling equipment, and the selection of components of milling machine drives.

Performance Improvement of Ultrasonic-Assisted Grinding Using PCD Micropin Tools

In the present study it was attempted to improve the performance of ultrasonic-assisted grinding using polycrystalline diamond (PCD) micropin tools processed by electrical discharge machining. The micropins acted as grinding tools because the convex parts of discharge craters can serve as cutting edges of abrasive grains in grinding wheels. The drilling conditions to prevent chippings and cracks on the hole edge were experimentally determined and then employed for the drilling of microholes less than 10 μm in diameter. As a result, microholes as small as 5.5 μm in diameter were successfully drilled in hard and brittle materials such as crown glass and monocrystalline silicon. The high wear resistance of PCD improved the tool life, making it possible to mill trenches and to mass-produce holes using a small number of tools. Moreover, the tool life was further improved by processing the tool peripheral surface at a low electrical discharge energy.

Surveying and High-Resolution Topography of the Ochtiná Aragonite Cave Based on TLS and Digital Photogrammetry

The Ochtiná Aragonite Cave (Slovakia, Central Europe) is a world-famous karst phenomenon of significant geological, geomorphological, and mineralogical values. Its specific origin is determined by particular lithological and hydrogeological conditions of the Ochtiná karst formed in lenses of Paleozoic crystalline limestones, partly metasomatically altered to ankerite and siderite. Although the cave is only 300 m long, it represents a combined labyrinth consisting in parallel tectonically controlled halls and passages, that are largely interconnected through transverse conduits of phreatic and epiphreatic morphology with many medium- and small-scale forms originated in slowly moving or standing water (flat solution ceilings, wall inward-inclined facets, water table notches, convectional cupolas, and spongework-like hollows). The highly dissected and irregular morphologies of the cave were surveyed with terrestrial laser scanning and digital photogrammetry. Both used surveying technologies proved to be suitable for quick and accurate mapping of the complicated cave pattern. While terrestrial laser scanning can provide a rapid survey of larger and more complex areas with results delivered directly in the field, digital photogrammetry is able to generate very high-resolution models with quality photo-texture for mapping of small-scale morphologies. Several data on cave morphometry were generated from terrestrial laser scanning (e.g., the area of cave ground plan, the peripheral surface of underground spaces, and their volume). The new detailed map, sections, and 3D model create an innovation platform for a more detailed study on the morphology and genesis of this unusual cave also for its environmental protection and use in tourism.

PERIPHERAL SURFACE DOSE FROM A LINEAR ACCELERATOR: RADIOCHROMIC FILM EXPERIMENTAL MEASUREMENTS OF FLATTENING FILTER FREE VERSUS FLATTENED BEAMS

There is a growing interest in the use of flattening filter free (FFF) beams due to the shorter treatment times. The reduction of head scatter suggests a better radiation protection to radiotherapy patients, considering the expected decrease in peripheral surface dose (PSD). In this work, PSD of flattened (FF) and FFF-photon beams was compared. A radiochromic film calibration method to reduce energy dependence was used. PSD was measured at distances from 2 to 50 cm to the field border for different square field sizes, modifying relevant clinical parameters. Also, clinical breast and prostate stereotactic body radiotherapy (SBRT) plans were studied. For square beams, FFF PSD is lower compared with FF PSD (differences ranging from 3 to 64%) and 10 MV FFF yields to the lowest value, for distances greater than 5 cm. For SBRT plans, near and far away from the field border, there is a reduction of PSD for FFF-beams, but the behavior at intermediate distances should be checked depending on the case.

Real time implementation of embedded devices as a security system in intelligent vehicles connected via Vanets

<p>The fast boom of technology has made our lives easier. The number of computer based functions embedded in cars have multiplied extensively over the past two decades. These days, many embedded sensors allowing localization and verbal exchange are being advanced to enhance reliability, protection and define new exploitation modes in intelligent guided transports. An in-car embedded electronic architecture is a complex setup machine, the improvement of that particular system is related to unique manufacturers and providers. There are several factors required in an efficient and secure system along with protection features, real time monitoring, reliability, robustness, and many other integrated features[1-2]. The appearance of modern era has also expanded the use of vehicles and its associated dangers. Dangers and the road accidents take place often which causes loss of lives and assets due to the bad emergency centres, lack of safety features and limitations within devices embedded within a vehicle. A rpm-speed calculating device can be used in a vehicle such that risku situations while driving can be detected. A system with Ultra sonic sensor can be used as a crash detector of the automobile in the course of the event and also after a crash. With indicators from the device, extreme coincidences also can be recognized. .As the amount of urban automobile grows automobile theft has become a shared difficulty for all citizens. As a solution an antitheft system can be implemented using PIR motion sensors where the system can be attached to the peripheral surface of the vehicle. When these sensors are interfaced with Arduino microcontroller an efficient and reliable security system can be developed[3].</p>

Application of ultrasonic testing method for determining defects of hot-deformed powder materials

The article is devoted to the analysis of elastic and plastic characteristics of composite materials during hot stamping. The purpose of this work is to offer optimal conditions for hot plasticity of composite porous material with determination of temperature conditions of hot stamping excluding the appearance of defects in the structure. Production of details of the difficult form by method of hot stamping from preparations of the cylindrical form is followed by development of barrel on a peripheral surface. Sludge sintered porous blanks, and sediment compact material, accompanied by a nonuniform height lateral deformation. In connection with the action of friction forces on the contact surfaces, this leads to the formation of a “barrel”. The heterogeneity of the deformed state is associated with the appearance of tangential tensile stresses on the free surface of the workpiece. If they exceed some critical degree of transverse deformation, cracks appear on the side surface, which leads to gas saturation (oxidation) of the inner layers of the forging, to the ingress of grease into them and its pressing into the volume of the part during hot stamping. In the end, this significantly reduces the properties of hot-stamped parts. Conclusion: the methods of determining the elastic characteristics depending on the geometric parameters of the workpieces, the applied strain energy, body density and temperature dependence of the plasticity characteristics of the hot deformation of the powder material are сonsidered.

Analysis of influence of the mono-crystalline corundum grinding wheel wear on grinding forces and roughness parameters in peripheral surface grinding of 100Cr6 steel

The paper presents the experimental study conditions and results of M3X60K5VE01-35 monocorundum with vitrified bond grinding wheel wear in 100Cr6 steel peripheral grinding process. The effect of grinding wheel wear on the values of grinding force components as well as surface roughness parameters was analyzed. The grinding wheel wear was determined by profile measurement of the active grinding wheel surface using an inductive sensor. It was shown that the increase in the normal component of the grinding force during the process can be an acceptable criterion for wear of the grinding wheel due to the quasi-linear changes over time.

Sequential analysis and staging of a diethylnitrosamine-induced hepatocellular carcinoma in male Wistar albino rat model

Hepatocellular carcinoma (HCC) is one of the most life-threatening cancers. The present study was designed to chronologically analyze the HCC chemically induced by diethylnitrosamine (DEN) in male Wistar rats during a 27-week period. DEN was given to rats in drinking water (100 mg/L) to induce HCC. In the present study, the DEN-administered groups recorded dramatic results in the tumor markers, oxidative stress, lipid profile, liver function, and hematological parameters at all intervals when compared with their corresponding values in the control groups. In addition, the morphometric analysis of livers of the DEN-administered groups (from 9 to 27 weeks) showed gradual enlargement and several grayish white nodules and foci on the peripheral surface of the liver as the features of HCC. In conclusion, the present sequential model chronologically analyzes all steps of hepatocarcinogenesis and presents a new staging system for classification of HCC that may be valuable for investigating the effects of anticarcinogenic compounds at varying stages of hepatocarcinogenesis in vivo.