scholarly journals Strengthening Thin-Walled Knives with Nitrogen Plasma

2021 ◽  
Vol 31 (1) ◽  
pp. 56-79
Author(s):  
Tamara S. Skoblo ◽  
Oksana Yu. Klochko ◽  
Anatoly K. Avtukhov ◽  
Vladimir N. Romanchenko ◽  
Artem V. Plugatarev ◽  
...  

Introduction. The completed developments are aimed at creating a new technology for increasing the wear resistance of a thin-walled instrument of complex configuration made of steel 65G for cutting beets at sugar enterprises. The most important requirement to improve the operability and durability of such a tool is the preservation of its profile and cutting edge during operation. Materials and Methods. A new developed equipment and technological process of strengthening using low-temperature nitrogen plasma were used to solve this problem. There have been determined optimal processing parameters that ensure the formation of a quasi-morphic structure on the friction surface that reduces the defectiveness of the cutting edge after its machining and also provides a process of self-sharpening due to tool strengthening on one side. Results. The comparative studies of the friction surface of products after operational tests have shown that their resistance increase significantly when strengthening both new and used products. This is determined by the nature of the quasi-morphic structure formed and the specific relief in friction on the working surface. Discussion and Conclusion. To describe the new process of strengthening thin-walled products, the structure formation on the friction surface was analyzed in detail with the use of metallographic images and its phase relationship variability was estimated by the optic-mathematical analysis of various zones (compression and vacuum) formed as friction bands. This was done trough modeling with the estimation of the distribution density of the conditional colors of the analyzed fragments.

2017 ◽  
Vol 898 ◽  
pp. 1289-1299 ◽  
Author(s):  
Feng Yi ◽  
Xue Feng Liu

Wide plates are mainly prepared through traditional cold mold continuous casting technology. A problem is cracking which caused by the non-uniform temperature field in solidification. Warm mold continuous casting is a new technology. Warm mold continuous casting of wide copper plate (section 500mm×12mm) was studies. Temperature field, solid/liquid interface and microstructure were analyzed by ProCAST software. By simulation, the optimal processing parameters: withdrawing speed was 60-80 mm/min, and the temperature of copper melt, mold and cooling water were 1200°C, 800-900oC and 20 oC, respectively. The temperature field in the width direction of the copper plate broad face was uniform, and the temperature decreased uniformly along the withdrawing direction. The temperature difference between center and edge was within 10 oC, and the temperature difference between narrow and broadfaces was within 25oC. Microstructure of plate contained ‘bamboo-like’ grains along the withdrawing direction.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1416
Author(s):  
Nur Aisyah Miza Ahmad Tamizi ◽  
Shayfull Zamree Abd Rahim ◽  
Abdellah El-hadj Abdellah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Marcin Nabiałek ◽  
...  

Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 274
Author(s):  
Shih-Jyun Shen ◽  
Demei Lee ◽  
Yu-Chen Wu ◽  
Shih-Jung Liu

This paper reports the binary colloid assembly of nanospheres using spin coating techniques. Polystyrene spheres with sizes of 900 and 100 nm were assembled on top of silicon substrates utilizing a spin coater. Two different spin coating processes, namely concurrent and sequential coatings, were employed. For the concurrent spin coating, 900 and 100 nm colloidal nanospheres of latex were first mixed and then simultaneously spin coated onto the silicon substrate. On the other hand, the sequential coating process first created a monolayer of a 900 nm nanosphere array on the silicon substrate, followed by the spin coating of another layer of a 100 nm colloidal array on top of the 900 nm array. The influence of the processing parameters, including the type of surfactant, spin speed, and spin time, on the self-assembly of the binary colloidal array were explored. The empirical outcomes show that by employing the optimal processing conditions, binary colloidal arrays can be achieved by both the concurrent and sequential spin coating processes.


2012 ◽  
Vol 730-732 ◽  
pp. 925-930
Author(s):  
Daniela Nunes ◽  
Vanessa Livramento ◽  
Horácio Fernandes ◽  
Carlos Silva ◽  
Nobumitsu Shohoji ◽  
...  

Nanostructured copper-diamond composites can be tailored for thermal management applications at high temperature. A novel approach based on multiscale diamond dispersions is proposed for the production of this type of materials: a Cu-nDiamond composite produced by high-energy milling is used as a nanostructured matrix for further dispersion of micrometer sized diamond. The former offers strength and microstructural thermal stability while the latter provides high thermal conductivity. A series of Cu-nDiamond mixtures have been milled to define the minimum nanodiamond fraction suitable for matrix refinement and thermal stabilization. A refined matrix with homogenously dispersed nanoparticles could be obtained with 4 at.% nanodiamond for posterior mixture with mDiamond and subsequent consolidation. In order to define optimal processing parameters, consolidation by hot extrusion has been carried out for a Cu-nDiamond composite and, in parallel, for a mixture of pure copper and mDiamond. The materials produced were characterized by X-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.


2008 ◽  
Vol 35 (4) ◽  
pp. 349-357 ◽  
Author(s):  
İlker Bekir Topçu ◽  
Mehmet Uğur Toprak ◽  
Devrim Akdağ

Microwave energy can accelerate the hydration of cement, which results in the rapid strength development of concrete. In this paper, prediction of later age compressive strength of fly ash cement mortars, based on the accelerated strength of mortars cured with microwave energy, was investigated. To accelerate curing properly, optimal processing parameters of microwave curing (MC) on Portland cement mortars (CM) and fly ash cement mortars (FA) were first determined and then were applied to mortars. The possible early ages for the strength prediction were found to be at 6 and 8 h for CM and FA, respectively. The error percentages for prediction of CM were ±2.22% and 2.91% for 7 and 28 d, respectively. Error percentages for FA, on the other hand, were ±4.36% and 5.20% for 7 and 28 d, respectively.


2021 ◽  
Author(s):  
Siti Najmi Farhan binti Zulkipli

Abstract Addressing wellbore integrity through cement evaluation has been an evergreen topic which frequently catches major operators by surprise due to premature water or gas breakthrough causing low production attainability from the wells. Managing idle well strings arising from integrity issues is also a challenge throughout the production period. The remedial solutions to these issues do not come conveniently and require high cost during late life well intervention which often erodes the well economic limit. A critical element of wellbore barrier which is cement integrity evaluation is proposed to be uplifted and given a new perspective to define success criteria for producer wells to achieve certain reserves addition and production recovery. This paper will highlight integrated factors affecting cement bond quality, impact to well production, potential remedies for poor cement bond observed leveraging on the enhanced workflow and new technology and way forward to proactively prevent the unwanted circumstances in the first opportunity taken. A set of recommendations and prioritization criteria for future cement improvement will be also highlighted. Several case specific wells logged with variable cement bond evaluation tools are re-assessed and deep-dived to trace the root causes for unsatisfactory cement bond quality observed which include reservoir characteristics, understanding anomalies during drilling and cementing operation, identifying cement recipe used, log processing parameters applied and observing best practices during cementing operation to improve the quality. New and emerging cement evaluation technology inclusive of radioactive-based logging to meet specific well objectives will be also briefly discussed in terms of differences and technical deliverables. Looking at each spectrum, results show that there are several interdependent factors contributing to poor cement bond quality observed. Accurate understanding of formation behavior, designing fit-for-purpose cement recipe and adequate planning for cementing operation on well-by-well basis are among the top- notch approaches to be applied for an acceptable cement bond quality and placement. Statistics show that 27% to 64% of production attainability is achieved by wells with good cement quality within the first 3 months of production and this increases to 85% to 98% up until 7 months of production period, while only 12% production attainability achieved for those wells with adverse cement quality issue. In another well, water cut as high as 47% since the first day of production is observed which keeps increasing up to 40% thereafter. In a nutshell, cement evaluation exercise shall not be treated as vacuum, instead it requires an integrated foundation and close collaboration to materialize the desired outcomes. Arresting the issue with the right approach in the first place will be the enabler for optimum well performance and productivity to exceed the recovery target.


Author(s):  
Dieudonne Essola ◽  
Achille Pandong Njomoue ◽  
Florence Offole ◽  
Cyrille Adiang Mezoue ◽  
Crick Nelson Zanga ◽  
...  

This work investigates the effect of low frequency vibratory processing for cleaning and washing various machine components parts from rusts and old paints deposits. The experimental investigation was carried out with special prepared samples that were weighted and exposed to paints and rust contaminants. These samples were treated in universal horizontal vibration machine UVHM 4 × 10 with different combination of instrumental processing medium, process fluid, machine amplitude and frequency of oscillations. They were periodically reweighted after processing and compared to etalon with control of quantity of dust that have been removed, sample cleanliness and also other functional parameters. Statistical analysis has been used to characterize ongoing process and full factorial analysis to establish experimental parameters dependency. The result is showing the complex dependence of samples cleanliness to each processing parameters like processing time, amplitude of oscillations, frequency of oscillations, process fluid parameters, instrumental medium, etc. Between this parameters although the most important successively the amplitude of oscillations, the frequency of oscillations the processing medium and the processing fluid depending to his considered composition, the optimal processing time can be reach only by complex combination of all this parameters every of them carry an amplify coefficient. Low frequency oscillations can be used to monitor and optimize washing and cleaning operations of paints and rusts contaminations. That guarantees process automation, its effectiveness for a large industrial application.


Webology ◽  
2021 ◽  
Vol 18 (05) ◽  
pp. 1158-1167
Author(s):  
Jagadeesan S ◽  
Mani C ◽  
Sambasivam S ◽  
Jaisankar P ◽  
Sasikala S

In the brand new technology of cutting-edge technological know-how and era is advanced day via way of means of day. The information confidentiality is danger everywhere in the global and it will increase rapidly. Steganography and cryptography are very vital strategies applied in facts safety to cowl and steady mystery messages in transmitting facts. In this we launch, put in force and check a completely sole technique that can be used as a steady and extraordinarily budget friendly technique {of facts|of knowledge|} interest in addition to information extracting (Jagadeesan, S., 2020). Some efficiency parameters are going to be thru an test received and in comparison with opportunity current approaches parameters to show the efficiency of the deliberate technique. Here we proposes a brand new method to hiding the information the use of steganography strategies primarily based totally on AES and RC5 set of rules cryptosystem. The word Steganography is the splendor of hiding mystery information in the back of the photos, videos, sound and textual content to cowl the name of the game communication. Cryptosystem is the system which given our technique extra perfection. The visible first-class of the quilt photo certainly nice, nobody can consider it how personal information are transmitted the use of this technique. This suggest technique and set of rules ability is exceedingly bendy than different posted set of rules. The AES and RC5 set of rules has no more difficulty and it looks as if thoroughly to hiding the personal information.


2020 ◽  
Vol 7 ◽  
Author(s):  
David C. Sheridan ◽  
Robert Cloutier ◽  
Andrew Kibler ◽  
Matthew L. Hansen

Sepsis currently affects over 30 million people globally with a mortality rate of ~30%. Prompt Emergency Department diagnosis and initiation of resuscitation improves outcomes; data has found an 8% increase in mortality for every hour delay in diagnosis. Once sepsis is recognized, the current Surviving Sepsis Guidelines for adult patients mandate the initiation of antibiotics within 3 h of emergency department triage as well as 30 milliliters per kilogram of intravenous fluids. While these are important parameters to follow, many emergency departments fail to meet these goals for a variety of reasons including turnaround on blood tests such as the serum lactate that may be delayed or require expensive laboratory equipment. However, patients routinely have vital signs assessed and measured in triage within 30 min of presentation. This creates a unique opportunity for implementation point for cutting-edge technology to significantly reduce the time to diagnosis of potentially septic patients allowing for earlier initiation of treatment. In addition to the practical and clinical difficulties with early diagnosis of sepsis, recent clinical trials have shown higher morbidity and mortality when septic patients are over-resuscitated. Technology allowing more real time monitoring of a patient's physiologic responses to resuscitation may allow for more individualized care in emergency department and critical care settings. One such measure at the bedside is capillary refill. This has shown favor in the ability to differentiate subsets of patients who may or may not need resuscitation and interpreting blood values more accurately (1, 2). This is a well-recognized measure of distal perfusion that has been correlated to sepsis outcomes. This physical exam finding is performed routinely, however, there is significant variability in the measurement based on who is performing it. Therefore, technology allowing rapid, objective, non-invasive measurement of capillary refill could improve sepsis recognition compared to algorithms that require lab tests included lactate or white blood count. This manuscript will discuss the broad application of capillary refill to resuscitation care and sepsis in particular for adult patients but much can be applied to pediatrics as well. The authors will then introduce a new technology that has been developed through a problem-based innovation approach to allow clinicians rapid assessment of end-organ perfusion at the bedside or emergency department triage and be incorporated into the electronic medical record. Future applications for identifying patient decompensation in the prehospital and home environment will also be discussed. This new technology has 3 significant advantages: [1] the use of reflected light technology for capillary refill assessment to provide deeper tissue penetration with less signal-to-noise ratio than transmitted infrared light, [2] the ability to significantly improve clinical outcomes without large changes to clinical workflow or provider practice, and [3] it can be used by individuals with minimal training and even in low resource settings to increase the utility of this technology. It should be noted that this perspective focuses on the utility of capillary refill for sepsis care, but it could be considered the next standard of care vital sign for assessment of end-organ perfusion. The ultimate goal for this sensor is to integrate it into existing monitors within the healthcare system.


Author(s):  
Xin Tong ◽  
Shucai Yang ◽  
Xianli Liu ◽  
Weiwei Liu ◽  
Chunsheng He

In the research regarding laser-processed micro-textured carbide tool surfaces, there remains a lack of research on the relationship between micro-textured preparation processes and the degree of fatigue wear experienced by micro-textured surfaces. To study the effect of a laser-textured surface on the friction and wear properties of friction pairs, it first of all conducted friction and wear tests to obtain optimal processing parameters. By using a scanning electron microscope, the fatigue wear mechanism for a micro-textured surface was observed. Experimental results based on fatigue wear theory show that a micro-textured surface phase has better fatigue resistance than a smooth surface. Under the same friction conditions and selected test parameters, a micro-textured surface phase can reduce the maximum fatigue and friction wear of a smooth surface by 38.4%. This study provides a theoretical basis and source of reference for the rational formulation of micro-texture parameters and improvements in the performance of micro-textures during cutting processes.


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