The Research into the Effect of Conditions of Combined Electric Powered Diamond Processing on Cutting Power

2017 ◽  
Vol 736 ◽  
pp. 81-85 ◽  
Author(s):  
D.V. Lobanov ◽  
Pavel V. Arkhipov ◽  
A.S. Yanyushkin ◽  
Vadim Yu. Skeeba
Keyword(s):  
Substantial Reduction ◽  
Disk Surface ◽  
Combined Method ◽  
Cutting Power ◽  
Abrasive Tools ◽  
Mechanical Cutting ◽  
Diamond Processing ◽  
Electrochemical Grinding ◽  
Diamond Abrasive

The paper presents results of the investigation into efficiency of high-tensile composite materials grinding with metal bonded diamond abrasive tools, as well as it demonstrates the necessity to stabilize diamond disks cutting properties in order to reduce cutting power, since it is one of important economic indicators of processing. The comparative analysis of preliminary studies of various diamond processing methods reveals that the minimal cutting power is observed when using the combined method of electric powered diamond processing which includes electrochemical grinding and simultaneous continuous electrochemical dressing of the grinding disk surface. Further research into the suggested method reveals relevant mathematical dependences of metal-bonded diamond disks cutting power and electric modes. The analysis of the results shows that combining of hard-alloy surface electrochemical dissolution and electrochemical dressing of the disk surface facilitates mechanical cutting with high effectiveness and little effort. This leads to substantial reduction of cutting power as compared with other methods. The reasonable electric modes are discovered which provide the minimal cutting power without reducing efficiency of the process and quality of finished product.

scholarly journals Research on The Bonding Properties of Vitrified Bonds With Porous Diamonds and The Grinding Performance of Porous Diamond Abrasive Tools

2021 ◽  
Author(s):  
Jianwei LI ◽  
Wenjun FANG ◽  
Long WAN ◽  
Xiaopan LIU ◽  
Weida HU ◽  
...  
Keyword(s):  
Wafer Surface ◽  
Processing Efficiency ◽  
Abrasive Particles ◽  
Bonding Properties ◽  
New Type ◽  
Vitrified Bond ◽  
Abrasive Tools ◽  
Grinding Efficiency ◽  
Diamond Abrasive

Abstract Ordinary diamond presents the disadvantages of poor self-sharpening and concentrated grinding stress when it is used as an abrasive. Moreover, this kind of diamond cannot be well wetted by the vitrified bond, resulting in a lower holding force of the binder to the abrasives (i.e., the diamond is easy to detach from the binder matrix during grinding). These comprehensive factors not only reduce the surface quality of the processed workpiece, but also hinder the processing efficiency. In order to solve these problems, a new type of porous diamond with high self-sharpening properties was prepared using a thermochemical corrosion method in this study. Our results showed a great improvement in pore volume and specific surface area of the porous diamond compared with ordinary diamond abrasive particles, and the holding force and wettability of vitrified bond to the porous diamond abrasive particles were also improved. Compared with ordinary diamond abrasive tools, porous diamond abrasive tools showed a 29.6% increase in grinding efficiency, a 15.5% decreased in grinding ratio, a 27.5% reduction in workpiece surface roughness, and the scratches on the silicon wafer surface were reduced and refined.

Simulation of the metallic powder mixing process and deterministic formation of homogeneity

2021 ◽  
pp. 93-100
Author(s):  
A. V. Evseev ◽  
V. V. Preys ◽  
N. E. Proskuryakov ◽  
A. V. Lobanov
Keyword(s):  
Mathematical Model ◽  
Cross Section ◽  
Metal Layer ◽  
Mixing Process ◽  
Special Design ◽  
Powder Mixing ◽  
Abrasive Tools ◽  
The One ◽  
Diamond Abrasive

This paper describes a mathematical model simulating the process of deterministic formation of a homogeneous mixture for making diamond abrasive tools. The process of modelling was divided into a few steps: – determining the capacity of the screw feeders; – determining how far the material is thrown by the screw; – building a cross-section of the distributed material; – determining the concentration of components within the microareas of a given size and calculating the mixture quality. The model provides a detailed description of the dosing process. They are the parameters of this process that mainly determine the quality of the resultant mixtures giving them a well-organized structure so that the diamond grains were distributed in the cutting metal layer as evenly as is desired. The obtained results have been verified through a series of full-scale experiments conducted in a special-design mixer. Thanks to this process, the resultant tool has a higher performance as compared with the one produced with the help of existing techniques.

Processability predictions for mechanically recycled blends of linear polymers

2020 ◽  
Vol 40 (9) ◽  
pp. 771-781
Author(s):  
Janne van Gisbergen ◽  
Jaap den Doelder
Keyword(s):  
Molecular Weight ◽  
Circular Economy ◽  
Melt Flow Index ◽  
Building Blocks ◽  
Experimental Designs ◽  
New Method ◽  
Flow Index ◽  
Linear Polymers ◽  
Combined Method

AbstractRecycling of thermoplastic polymers is an important element of sustainable circular economy practices. The quality of mechanically recycled polymers is a concern. A method is presented to predict the structure and processability of recycled blends of polymers based on processability knowledge of their virgin precursor components. Blending rules at molecular weight distribution level are well established and form the foundation of the new method. Two essential fundamental building blocks are combined with this foundation. First, component and blend structure are related to viscosity via tube theories. Second, viscosity is related to melt flow index via a continuum mechanics approach. Emulator equations are built based on virtual experimental designs for fast forward and reverse calculations directly relating structure to viscosity and processability. The new combined method is compared with empirical blend rules, and shows important similarities and also clear quantitative differences. Finally, the new method is applied to practical recycling quality challenges.

scholarly journals Enhancement of Region of Interest CT Reconstructions through Multimodal Data

2018 ◽  
Vol 4 (1) ◽  
pp. 331-335
Author(s):  
David Schote ◽  
Tim Pfeiffer ◽  
Georg Rose
Keyword(s):  
Substantial Reduction ◽  
Region Of Interest ◽  
Proof Of Concept ◽  
Multimodal Data ◽  
New Approach ◽  
Full Field ◽  
Lack Of Information ◽  
Ct Data ◽  
Flight Measurements

AbstractComputed tomography (CT) scans are frequently used intraoperatively, for example to control the positioning of implants during intervention. Often, to provide the required information, a full field of view is unnecessary. I nstead, the region-of-interest (ROI) imaging can be performed, allowing for substantial reduction in the applied X-ray dose. However, ROI imaging leads to data inconsistencies, caused by the truncation of the projections. This lack of information severely impairs the quality of the reconstructed images. This study presents a proof-of-concept for a new approach that combines the incomplete CT data with ultrasound data and time of flight measurements in order to restore some of the lacking information. The routine is evaluated in a simulation study using the original Shepp-Logan phantom in ROI cases with different degrees of truncation. Image quality is assessed by means of normalized root mean square error. The proposed method significantly reduces truncation artifacts in the reconstructions and achieves considerable radiation exposure reductions.

Defect Reduction and Defect Engineering in Silicon-on-Sapphire Material Using Ge Implantation

1990 ◽  
Vol 201 ◽  
Author(s):  
F. Namavar ◽  
E. Cortesi ◽  
N. M. Kalkhoran ◽  
J. M. Manke ◽  
B. L. Buchanan
Keyword(s):  
Leakage Current ◽  
Defect Density ◽  
Solid Phase ◽  
Substantial Reduction ◽  
Interface Region ◽  
Radiation Environment ◽  
Solid Phase Epitaxy ◽  
Defect Reduction ◽  
Radiation Induced

AbstractSubstantial reduction of defect density in silicon-on-sapphire (SOS) material is required to broaden its range of applications to include CMOS and bipolar devices. In recent years, solid phase epitaxy and regrowth (SPEAR) and double solid phase epitaxy (DSPE) processes were applied to SOS to reduce the density of defects in the silicon. These methods result in improved carrier mobilities, but also in increased leakage current, even before irradiation. In a radiation environment, this material has a large increase in radiation induced back channel leakage current as compared to standard wafers. In other words, the radiation hardness quality of the SOS declines when the crystalline quality of the Si near the sapphire interface is improved.In this paper, we will demonstrate that Ge implantation, rather than Si implantation normally employed in DSPE and SPEAR processes, is an efficient and more effective way to reduce the density of defects near the surface silicon region without improving the Si/sapphire interface region. Ge implantation may be used to engineer defects in the Si/sapphire interface region to eliminate back channel leakage problems.

Effect of Abrasive Tools in Galvanomechanical Treatment on the Roughness of the Deposited Chromium Layer

2018 ◽  
Vol 284 ◽  
pp. 1178-1183 ◽  
Author(s):  
D.A. Zherebtcov ◽  
Oksana N. Gruba ◽  
K.R. Smolyakova
Keyword(s):  
Experimental Studies ◽  
The Body ◽  
Abrasive Tool ◽  
Chromium Layer ◽  
Pressing Force ◽  
Hard Chromium ◽  
Chromium Plating ◽  
Cylindrical Parts ◽  
Abrasive Tools

The article deals with the method of obtaining a hard chromium coating on details of the "body of rotation" type with the use of an abrasive tool. The influence of the composition and hardness of the elastic abrasive tool on the results of galvanomechanical chromium plating of rotating cylindrical parts has been studied. Binder compositions for an abrasive tool used to improve the roughness of the deposited chromium layer have been developed. A series of experimental studies has been carried out with chromium plating of steel cylindrical parts with simultaneous abrasive processing. Beforehand, an abrasive tool with previously developed binder formulations was manufactured. The obtained results of the influence of the characteristics of the abrasive tool and its pressing force on the chromium-plated part on the quality of the precipitated chromium made it possible to determine the optimum modes for obtaining a coating of the required thickness. Also, a suitable abrasive tool has been chosen to obtain a coating of proper quality.

Regional blockade for prolonged anesthesia in enucleation and evisceration

Reflection ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 47-55
Author(s):  
I.G. Oleshchenko ◽  
◽  
О.P. Mishchenko ◽  
М.А. Gasparyan ◽  
◽  
...  
Keyword(s):  
Postoperative Period ◽  
Choroidal Melanoma ◽  
Opioid Analgesics ◽  
Early Postoperative Period ◽  
Alternative Methods ◽  
Combined Method ◽  
Retrobulbar Anesthesia ◽  
Pterygopalatine Ganglion ◽  
Systemic Side Effects

Regional anesthesia is widely used in ophthalmology both as an independent method and in combination. Retrobulbar anesthesia has risks of complications and is undesirable in the surgical treatment of choroidal melanoma due to the risk of metastasis of tumor cells when it is performed. Therefore, it is necessary to search for alternative methods of regional blockades in order to create prolonged anesthesia. Purpose. To develop and evaluate the clinical efficacy of pterygopalatine blockade as a component of combined method of anesthesia for evisceration or enucleation of the eyeball. Methods. A comparative analysis of the effectiveness of intraoperative anesthesia and the course of postoperative period was carried out in patients of two clinical groups formed depending on the method of anesthesia. Results. Intraoperative monitoring of hemodynamics in the groups did not differ. The nature of pain in the patients of the compared groups in the postoperative period had significant differences in presence and intensity of pain on the scale of verbal sensations. Discussion. Use of pterygopalatine blockade with levobupivacaine in combination with dexamethasone as an adjuvant allows getting a prolonged analgesic, anti-inflammatory and decongestant effect. This makes it possible to avoid the use of opioid analgesics in the early postoperative period, that is, to avoid such systemic side effects as nausea, dizziness, and in rare cases vomiting, which generally improves the quality of the postoperative period. Conclusions. Use of pterygopalatine ganglion blockade with local prolonged-acting anesthetic levobupivacaine and dexamethasone as an adjuvant based on inhaled anesthesia with sevoflurane provides safe and effective anesthesia in patients with evisceration or enucleation of the eyeball, both in the intra- and postoperative period. Key words: enucleation; evisceration; pterygopalatine blockade; dexamethasone.

Fabrication and Application of Gel Forming Ultrafine Diamond Abrasive Tools

2021 ◽  
Vol 10 (6) ◽  
pp. 063009
Author(s):  
Kaiping Feng ◽  
Binghai Lyu ◽  
Tianchen Zhao ◽  
Zhaozhong Zhou
Keyword(s):  
Ultrafine Diamond ◽  
Abrasive Tools ◽  
Diamond Abrasive

Advances in C. elegans Specimen Preparation for TEM Using Microwave and Fast Freeze Techniques

2001 ◽  
Vol 7 (S2) ◽  
pp. 1196-1197
Author(s):  
D.H. Hall ◽  
T. Starich ◽  
J. Shaw ◽  
V. Gobel ◽  
J. Fleming ◽  
...  
Keyword(s):  
Freeze Substitution ◽  
Microwave Energy ◽  
Specimen Preparation ◽  
Genetic Studies ◽  
Larval Cuticle ◽  
C Elegans ◽  
Larval Stages ◽  
Mechanical Cutting ◽  
Fast Freezing

The nematode C. elegans is a simple model for genetic studies of cell and tissue development. There is a need to improve the preservation of embryonic and early larval stages, during which nematode tissues elaborate and separate. However, these stages are particularly resistant to fixation and embedment due an impenetrable eggshell and larval cuticle. Their small size at these ages precludes mechanical cutting, which has been used successfully for immersion fixation of older stages. Here we compare the quality of preservation under three rather different regimes: using laserholes to permeabilize the eggshell during the primary fixation step, using microwave energy to enhance the first fixation step, or using fast freezing and freeze substitution to circumvent the standard immersion procedure. Vancoppenolle et al (2000) have recently demonstrated very good results through enzymatic weakening of the eggshell prior to immersion fixation. Their data are comparable to what we achieve by either the laserhole or microwave methods.

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