An Experimental Study on Edge-Breakage of Explosive Parts in Machining Using Micro-Photographic Observation Method

2012 ◽  
Vol 214 ◽  
pp. 370-374
Author(s):  
Wei Tang ◽  
Wei Liu ◽  
Qing Xi ◽  
Tong Liu ◽  
Ding Guo Zhang
Keyword(s):  
Final Stage ◽  
Rake Angle ◽  
Sharp Edge ◽  
Work Piece ◽  
Initial Stage ◽  
Deep Rock ◽  
Cutting Zone ◽  
Extension Direction ◽  
Weak Surface ◽  
Observation Method

Crack on the sharp edge remains a major concern and a key problem cries for solution in the course of explosive cutting currently. The adoption of the idea that enlarges the cutting zone and records the cutting behaviors again has founded the micro-photographic system for the cutting process. Tests have found that this system can be applied to research the nucleation and expansion of deep rock crack and the formation and dropping of the chips. The extension direction that controls the cracks is the key to resolve the cracks on the sharp edge. As for the initial stage of cutting, the cracks usually expand from the relatively weak surface of the work piece, while the final stage of the cutting, the cracks point to the weak end face through the inner part of the work piece. The latter is easier to have the cracks on the sharp edge comparing to the former. Working orthogonal rake of tool is an important factor that affects the extension direction of the cracks. At the final stage of the cutting, if the working orthogonal rake is -6°, the angel from the crack extension direction to the main cutting direction is -35°. When the working orthogonal rake is 9°, the angel turns to be -54°. This has shown that enlarging the working orthogonal rake to a certain extend can lower the degree of crack on the sharp edge. In addition, tests have found out that the relatively small working orthogonal rake is likely to bring out potential cracks. However, enlarging the rake angle excessively will lower the rigidity of the tool and thus add risks of shocking.

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
A.M. Zetty Akhtar ◽  
M.M. Rahman ◽  
K. Kadirgama ◽  
M.A. Maleque
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Base Fluid ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Cutting Zone ◽  
Observation Method ◽  
The Stability ◽  
The Relationship ◽  
Zeta Potential Analysis

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

THE DEHYDRATION OF PORK

1943 ◽  
Vol 21d (12) ◽  
pp. 394-404
Author(s):  
Jesse A. Pearce
Keyword(s):  
Moisture Content ◽  
Final Stage ◽  
Open Steam ◽  
Raw Meat ◽  
Initial Stage ◽  
Drying Procedures ◽  
Tray Drying

Four preprocessing and three drying procedures for the dehydration of pork were studied. The best product resulted from cooking in an open steam-jacketed kettle, followed by mincing and tunnel–tray drying in four hours or less with a tray load of 2 lb. per square foot. Little difference in quality of the product was observed for air velocities of 700 to 1200 ft. per min. over the trays, or for initial stage temperatures between 70° and 80 °C. and final stage temperatures between 55° and 70 °C.Pork, when dried to a moisture content of 3 to 4% in less than four hours, still retained a high percentage of the thiamin present in the raw meat, showed no fat deterioration when assessed by peroxide oxygen determinations, and on reconstitution had a palatability rating approximately equal to that of the initial cooked material.

Performance Profiling of Nanoparticulate Graphite Powder as Lubricant in the Machining of AISI 1040 Steel under Variable Machining Conditions

2014 ◽  
Vol 984-985 ◽  
pp. 15-24 ◽  
Author(s):  
S. Srikiran ◽  
K. Ramji ◽  
B. Satyanarayana
Keyword(s):  
Particle Size ◽  
Surface Finish ◽  
Cutting Forces ◽  
Solid Lubricant ◽  
Graphite Powder ◽  
Nano Particles ◽  
Chemical Degradation ◽  
Work Piece ◽  
Tool Temperature ◽  
Cutting Zone

The generation of heat during machining at the cutting zone adversely affects the surface finish and tool life. The heat at the cutting zone, which plays a negative role due to poor thermal conductivity, resistance to wear, high strength at high temperatures and chemical degradation can be overcome by the use of proper lubrication. Advancements in the field of tribology have led to the use of solid lubricants replacing the conventional flood coolants. This work involves the use of nanoparticulate graphite powder as a lubricant in turning operations whose performance is judged in terms of cutting forces, tool temperature and surface finish of the work piece. The experimentation revealed the increase in cutting forces and the tool temperature when the solid lubricant used is decreased in particle size. The surface finish deteriorated with the decrease in particle size of the lubricant in the nanoregime.Keywords-Turning, Solid lubricant, Graphite, Minimum Quantity Lubrication, nano–particles,Weight percentage,Frictioncoefficient.

Influence of Depth of Cut on Contact Phenomenon in Micromachining

2014 ◽  
Vol 660 ◽  
pp. 8-12
Author(s):  
J.B. Saedon ◽  
Noor Aniza Norrdin ◽  
Mohd Azman Yahaya ◽  
N.H. Mohamad Nor ◽  
Mohd Zulhafiz Md Salih
Keyword(s):  
Cutting Tool ◽  
Chip Thickness ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Work Piece ◽  
Arbitrary Lagrangian Eulerian ◽  
Contact Phenomenon ◽  
Aisi D2 ◽  
Material Separation ◽  
Contact Distribution

Chip formation is a dynamic process that is often nonlinear in nature. A chip may not form when the depth of cut is less than a minimum chip thickness. It is aimed to investigate influence of depth of cut on contact phenomenon in micromachining. This paper presents a series of simulation works by finite element method on depth of cut effect on micromachining. A model is developed with consideration of the Johnson-Cook material and Arbitrary Lagrangian–Eulerian (ALE) method. In this work investigate the effect of depth of cut on the contact phenomenon during micromachining AISI D2. The results of the analysis are showed in aspects of interrelationship between material separation and frictional shear contact, distribution of stick-slide regions and contact stress on the work piece and cutting tool. It is found that the sticking and sliding was occurred on three zones as primary, secondary and tertiary shear zone. The contact phenomena can be showed around the tool edge radius where material flows around it and piles in front of the cutting tool through material separation. The investigation of contact phenomena inclusive under three criteria such as a/r < 1, a/r > 1 and a/r = 1 on positive rake angle.

Influence of compaction and degassing on the properties of submicron WCCo produced by the PPS method

2019 ◽  
Vol 108 ◽  
pp. 5-12
Author(s):  
JOANNA WACHOWICZ ◽  
MARCIN ROSIŃSKI ◽  
RADOSŁAW ZIELIŃSKI ◽  
TOMASZ TRUSZKOWSKI
Keyword(s):  
Fracture Toughness ◽  
Heating Rate ◽  
Final Stage ◽  
Sintering Temperature ◽  
Cobalt Content ◽  
Operation Temperature ◽  
Plasma Sintering ◽  
Initial Stage ◽  
Temperature Load ◽  
Pulse Plasma Sintering

Influence of compaction and degassing on the properties of submicron WCCo produced by the PPS method. The present study is concerned with the effect of the parameters of the degassing operation (temperature, load and heating rate) conducted at the initial stage of the Pulse Plasma Sintering (PPS) process and the sintering temperature at the final stage of the process, on the properties and microstructure of WCCo with a 6wt% cobalt content sintered by this method. The results of the study have shown that when the heating rate is too high, the material obtained is porous. In most experiments, the sintering temperature of 1050°C appeared to be too low to obtain WCCo composites with density close to the theoretical value (GT). Sintering at the temperature increased to 1070°C yielded sinters with density above 99%GT, with hardness of about 1900 HV30 and fracture toughness KIC=9.3 MNm-3/2.

scholarly journals INVESTIGATION INTO TT TECHNOLOGICAL PROPERTIES OF COOLANTS WITH LIQUID CRYSTAL ADDITIVES / TEPIMO IR AUŠINIMO SKYSČIO SU SKYSTŲJŲ KRISTALŲ PRIEDAIS TECHNOLOGINIŲ SAVYBIŲ TYRIMAS

2012 ◽  
Vol 3 (6) ◽  
pp. 71-74
Author(s):  
Vaidas Strolia ◽  
Vadim Mokšin ◽  
Robertas Urbanavičius
Keyword(s):  
Liquid Crystals ◽  
Comparative Research ◽  
Liquid Crystalline ◽  
Work Piece ◽  
Machined Surface ◽  
Mineral Oils ◽  
Twisted Nematic ◽  
Iron Work ◽  
Cutting Zone ◽  
Oil Emulsions

The paper presents the results of comparative research on the roughness and tool life of the machined surface when steel and cast iron work pieces were turned, reamed and tapped and the cutting zone was lubricated by various coolants (mineral oils, oil emulsions) with and without twisted nematic liquid crystals. The tested liquid crystals were taken from the same homologous series (fatty acid cholesterol esters) but had different molecular mass. It has been established that the most positive tribological effect of liquid crystalline additives is achieved when high-molecular liquid crystals are used in operations characterized by the largest tool-work piece interface area (reaming, threading). Santrauka Straipsnyje pateikti apdirbto paviršiaus šiurkštumo ir įrankių patvarumo matavimo rezultatai, kai plieno ir ketaus paviršiai buvo tekinami, plečiami ir sriegiami sriegikliais, pjovimo zoną tepant ir aušinant įvairiais tepimo ir aušinimo skysčiais su cholesterinių skystųjų kristalų priedais ir be priedų. Buvo naudojami skirtingos molekulinės masės vienos homologinės eilės cholesteriniai skystieji kristalai (cholesterolio esteriai) ir skirtingi tepimo ir aušinimo skysčiai: tepalai ir mineralinių tepalų vandens emulsijos. Nustatyta, kad didžiausias teigiamas skystųjų kristalų priedų efektas pasiekiamas tų operacijų metu, kai įrankio ir detalės kontakto plotas yra didesnis (pvz., plečiant, sriegiant). Taip pat nustatyta, kad didžiausiu tribologiniu efektu pasižymi didesnės molekulinės masės skystieji kristalai.

scholarly journals A Systematic Research on the Working Mechanism of Decategorization of Nouns in Mandarin Chinese

2019 ◽  
Vol 9 (2) ◽  
pp. 188
Author(s):  
Zhen Li
Keyword(s):  
Mandarin Chinese ◽  
Systematic Study ◽  
Final Stage ◽  
Systematic Research ◽  
Target Domain ◽  
Working Mechanism ◽  
Source Domain ◽  
Initial Stage ◽  
Theory Of Duality ◽  
Metaphor And Metonymy

Based on the previous research, this paper makes a systematic study of the working mechanism of decategorizaiton of nouns in Mandarin Chinese, employing the theories of metaphor and metonymy and the theory of duality of concept. The major findings are as follows: metonymy-metaphor interaction is the working mechanism in the decategorization of nouns in Mandarin Chinese, mainly metaphor from metonymy, with metonymy and metaphor, functioning at different stages of decategorization. At the initial stage, the basic working mechanism is WHOLE-PART METONYMY. By this mechanism, a certain meaning component in the type notion domain of a noun is highlighted through metonymical constituent perspectivization and subjectivization, expressing descriptive or assertive meaning related to the noun. At the final stage, the working mechanism is mainly categorical metaphor, of which the source domain is the token notion of a typical noun with concrete meaning while the target domain is the type notion with abstract sense intended to express in communication.

scholarly journals Selection of rational electrochemical methods for controlling the efficiency of machining of corrosion-resistant steel

2021 ◽  
Vol 2131 (4) ◽  
pp. 042016
Author(s):  
Yu Astsaturov ◽  
S Solovyov ◽  
V Zhigulsky
Keyword(s):  
Anodic Polarization ◽  
Metal Cutting ◽  
Electrolyte Solutions ◽  
Rotating Disk Electrode ◽  
Polarization Curves ◽  
Work Piece ◽  
Mechanical Processing ◽  
Electrode Potentials ◽  
Cutting Zone ◽  
Selection Of

Abstract The article discusses methods of controlling the processes of mechanical processing based on electrochemical effects. The corresponding anodic polarization curves of 1X18H9T steel obtained in electrolyte solutions without and with stirring are presented. The article discusses methods of machining processes control based on electrochemical effects. Lubricating and cooling technological media (LCTM) used in machining are in most cases electrolytes, therefore, electrochemical processes and phenomena actively occur during contact dynamic machining. It is possible to control the processes of machining by acting on the system elements of the tool - LCTM- part, in particular by activating the LCTM and reducing the strength characteristics of the processed steel in the cutting zone. A reserve for increasing the efficiency of mechanical processing can be the composition selection of the applied LCTM, combined with the simultaneous electrochemical polarization of the treated surface of friction pair parts. It was found that when cutting, the efficiency of machining and the chip shapes are changed, which is explained by the influence of the current density on the strength of the processed steel. In the conditions of machining, complex dynamic processes occur due to the rotation of the work piece and/or tool, so it is necessary to take into account the hydrodynamic phenomena and processes that arise in this case. Electrode potentials are considered to be the most important characteristic of the metal cutting process. The potential of the system can regulate such processes and indicators as wear and surface micro hardness. Anodic polarization curves of the steel 1X18H9T obtained in various electrolyte solutions without stirring and with stirring on a rotating disk electrode are given. The study allowed determining the factors affecting the processes occurring in the cutting zone and to identify rational current densities due to simulating the conditions of real technological processes of the combined steel processing. The increase in the processing intensity of the steel 1X18H9T with the cutting zone polarization is associated with the action of factors activating the selective anodic dissolution of the processed alloy.

scholarly journals PROGRAM LAYANAN KONSELING KELUARGA YANG TERDAMPAK COVID 19 DI DESA KALIJAYA KECAMATAN TELAGASARI KABUPATEN KARAWANG

2021 ◽  
Vol 3 (1) ◽  
pp. 11-21
Author(s):  
Sri Wulan Anggraeni ◽  
Lusiana Rahmatiani ◽  
Refiza Praditya Alam
Keyword(s):  
Community Service ◽  
Final Stage ◽  
Counseling Services ◽  
Counseling Service ◽  
Counseling Relationship ◽  
Service Program ◽  
Initial Stage ◽  
The Family ◽  
Service Activity ◽  
The Impact

Latar belakang dalam pengabdian ini adalah dampak yang ditimbulkan dari covid 19 sangat dirasakan bagi keluarga, tak terkecuali pada aspek perekonomian dan psikologis keluarga.. Tujuan kegiatan Pengabdian Pada Masyarakat ini adalah bertujuan untuk memberikan pelayanan konseling kepada keluarga yang terdampak covid 19 untuk dapat meningkatkan motivasi keluarga agar dapat menjalani kehidupan dengan lebih baik lagi. Sasaran kegiatan ini adalah Keluarga yang terdampak covid 19 Kecamatan Telagasari Desa Kalijaya Kabupaten Karawang yang berjumlah satu keluarga yang terdiri dari 4 orang yaitu ayah, ibu, dan dua anak. Metode yang digunakan dalam kegiatan ini terdiri dari beberapa tahapan yaitu tahap awal yang diri dari membangun hubungan konseling dengan klien, mendefinisikan masalah, penjajakan, dan menegosiasikan kontak, selanjutnya tahap kerja yang meliputi penjajakan masalah, bantuan yang diberikan terhadap klien, dan tahap akhir yaitu progress klien. Hasil yang diperoleh adalah proses konseling berhasil untuk meningkatkan motivasi keluarga yang terdampak covid 19. Hal ini dibuktikan dengan adanya perubahan yang terjadi pada klien setelah mengikuti kegiatan konseling yaitu perubahan klien tidak terpuruk lagi dan berusaha bangkit mencari nafkah dan anak-anak klien tetap semangat, sehingga dikatakan untuk program layanan konseling ini dikatakan berhasil. Kata Kunci: Layanan Konseling, Keluarga, Covid 19 The background in this service is that the impact of Covid 19 is felt on families, including the economic and psychological aspects of the family. The purpose of this Community Service activity is to provide counseling services to families affected by Covid 19 to increase family motivation. in order to live life better. The targets of this activity are families affected by covid 19, Telagasari Subdistrict, Kalijaya Village, Karawang Regency, which consists of one family consisting of 4 people, namely father, mother, and two children. The method used in this activity consists of several stages, namely the initial stage which consists of building a counseling relationship with clients, defining problems, exploring, and negotiating contacts, then the work stage includes exploring problems, assistance provided to clients, and the final stage, namely progress. client. The results obtained were that the counseling process was successful in increasing the motivation of families affected by covid 19. This is evidenced by the changes that occur in clients after participating in counseling activities, namely changes in clients do not fall anymore and try to get up to earn a living and the client's children remain enthusiastic, so that the counseling service program is said to be successful. Keywords: Counseling Services, Family, Covid 19          

scholarly journals Pemanfaatan Air Buangan Ac Untuk Tanaman Hias Berbasis Internet Of Things

2019 ◽  
Vol 16 (1) ◽  
pp. 1
Author(s):  
Eky Arjayanto Nurhasana ◽  
Hermansyah Hermansyah ◽  
Lely Aylia ◽  
Kasim Kasim
Keyword(s):  
Waste Water ◽  
Internet Of Things ◽  
Final Stage ◽  
Electronic Circuit ◽  
Electronic Devices ◽  
Ornamental Plants ◽  
Environmentally Friendly ◽  
Initial Stage ◽  
Iot Devices ◽  
The Right

In relation to utilizing AC waste water and the use of water in watering plantsespecially ornamental plants and provide awareness for efforts to save water. By usingapplication of Internet of Things (IoT) based electronic circuit which is one of the programsdeveloped to facilitate the process of watering and fertilizing plants automatically. One ofthe way you can do this is by using IoT devices as a control device.This product is expected to be a product that can be sold to the market at an affordable price. andhas a function that is environmentally friendly and can be used by all people in the future. Activitiesmaking this product starts with the initial stage of observing the room using AC and makingdesign model, after getting the right room, then is to prepare the device to beused to make products both electronic and non-electronic devices and finally prepare toolswhich will be used for installation and configuration of the tool. After the product is finished, the next is testingproduct. The final stage includes functional checks to determine whether the tool is functioning properly based onsystem design that has been designed.

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