Study on the Plastic Removal Mechanism of Nano-ZrO2 Ceramics by Ultrasonic Grinding

2010 ◽  
Vol 455 ◽  
pp. 686-689 ◽  
Author(s):  
Jin Xue Xue ◽  
Bo Zhao ◽  
Guo Fu Gao
Keyword(s):  
Removal Mechanism ◽  
Engineering Ceramics ◽  
High Toughness ◽  
Ductile Grinding ◽  
Ultrasonic Grinding ◽  
Conventional Grinding ◽  
Length Width ◽  
The Common ◽  
Cracking Process ◽  
New Formula

The brittleness, plasticity, super-plasticity and the removal mechanisms of critical fragmentation of the nano ZrO2 ceramics were investigated. The formula of critical ductile grinding depth of the common engineering ceramics was inapplicable to the nano-ZrO2 ceramics. A new formula of critical ductile grinding depth of the nano ceramics was established. The ultrasonic vibration grinding experiments showed that the critical ductile grinding depth of the ceramics was 15μm by conventional grinding, but the increment of the critical ductile grinding depth was 60 percent by ultrasonic grinding. The critical ductile grinding depth increased to 25μm. Analyzed by means of SEM, it was transgranular cracking during its cracking process. The nano-ZrO2 ceramics have high toughness so the critical ductile grinding depth increased. The shape, length, width and thickness of the grindings differed greatly from which obtained by conventional grinding.

Study on Ultrasonic Grinding Method and Mechanism of the Engineering Ceramic Material

2009 ◽  
Vol 416 ◽  
pp. 492-496
Author(s):  
Hua Li Su ◽  
Jun Liu ◽  
Quan Fang Gai
Keyword(s):  
Material Removal ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Engineering Ceramics ◽  
Engineering Ceramic ◽  
Grinding Method ◽  
Ultrasonic Grinding ◽  
Complex Cavity ◽  
Preliminary Study ◽  
Processing Mechanism

It is one of the feasible methods to resolve the complex cavity processing by carrying on rotary ultrasonic grinding machining with the simple tools. On the basis of the theory processing engineering Ceramics, this paper designed the rotary ultrasonic grinding tools and analyzed the material removal mechanism by using rotary ultrasonic grinding NC engineering ceramics processing technology; and carried on a preliminary study to the rotary ultrasonic grinding processing mechanism.

Research on Removal Mechanism and Surface Features of Al2O3 Engineering Ceramics in Ultrasonic Lapping

2014 ◽  
Vol 621 ◽  
pp. 146-152
Author(s):  
Chang Juan Zhang ◽  
Jing Lin Tong ◽  
Bo Zhao ◽  
Feng Jiao
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Microstructure ◽  
Machining Efficiency ◽  
Removal Mechanism ◽  
Engineering Ceramics ◽  
The Common

Ultrasonic lapping can effectively improve machining efficiency and obtain higher machining precision, which can be as the final process. This paper discusses the ultrasonic lapping mechanism through simulating the lapping tracks. Based on the contrast experiments between common and ultrasonic lapping, the influence of different lapping parameters on material removal rate and surface roughness were studied and the surface microstructure of workpiece was analyzed. The experimental results show that material removal rate of ultrasonic lapping is nearly two times that of the common lapping, especially in ultrasonic axial lapping, and the better surface quality can be obtained during ultrasonic lapping. Meanwhile, the reasons for material removal rate increasing and surface quality improving were analyzed.

Study on Critical Ductile Grinding Depth of Nano ZrO2 Ceramics by the Aid of Ultrasonic Vibration

2006 ◽  
Vol 304-305 ◽  
pp. 232-235 ◽  
Author(s):  
Dao Hui Xiang ◽  
Y.P. Ma ◽  
Bo Zhao ◽  
Ming Chen
Keyword(s):  
Ultrasonic Vibration ◽  
Crack Extension ◽  
Grinding Force ◽  
Ultrasonic Machining ◽  
Removal Mechanism ◽  
Grinding Forces ◽  
Ductile Grinding ◽  
High Efficient ◽  
Finished Surface ◽  
Ductile Removal

The crack extension course and ductile removal mechanism of nano ZrO2 ceramics were analyzed in this paper. On the basis of contrast tests with or without ultrasonic vibration, the influences of critical ductile grinding depth on grinding forces and surface quality were studied by dynamometer, SEM and AFM in different grinding condition. The reason for the increase of the critical grinding depth was discussed based on the analysis of grinding force and ultrasonic vibration course. At last, the formation mechanism of surface topography observed by AFM in ductile domain was analyzed. The research indicated that ultrasonic machining could obtain nano finished surface with high efficient.

Surface Behaviors of ELID Ground Engineering Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1469-1472 ◽  
Author(s):  
Jian Yun Shen ◽  
Wei Min Lin ◽  
Hitoshi Ohmori ◽  
Xi Peng Xu
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Material Removal ◽  
Grinding Process ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Silicon Nitride Ceramic ◽  
Engineering Ceramics ◽  
Elid Grinding ◽  
Engineering Ceramic

In this study, grinding of Si3N4, SiC, and Al2O3 ceramics under the condition of electrolytic in-process dressing (ELID) system was investigated. The surface appearances of these engineering ceramics during the ELID grinding process were attentively observed to describe the formation of finely finished surfaces. Based on the analysis of material properties and detailed micro-observation of ground surfaces, it can be concluded that the material removal mechanism of engineering ceramic is closely related to its mechanical properties. The silicon nitride ceramic was most easily machined to precision surface among these three engineering ceramics.

scholarly journals Morphological aspects of fruits, seeds, and seedlings, and anatomy of seedlings of apuleia molaris spruce ex benth

2016 ◽  
Vol 38 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Alisson Rodrigo Souza Reis ◽  
Alessandra Doce Dias de Freitas ◽  
Noemi Vianna Martins Leão ◽  
Benedito Gomes dos Santos Filho
Keyword(s):  
Vascular Bundle ◽  
Scientific Knowledge ◽  
Morphological Characteristics ◽  
Plant Anatomy ◽  
The State ◽  
Fast Growing ◽  
Morphological Aspects ◽  
Field Identification ◽  
Length Width ◽  
The Common

Abstract: Apuleia molaris spruce ex benth, commonly known in Brazil as "amarelão," is a fast-growing forest plant with a potential for use in reforestation; however, there is little information about the physiology and morphology of its fruits, seeds, and seedlings. Thus, the objective of this work was to describe the morphology of the fruits, seeds, and seedlings, in addition to the anatomic patterns of seedlings, as a contribution to the technical-scientific knowledge and production of amazonian species for reforestation in the state of Pará. For this purpose, the morphological descriptions followed the parameters from specialized literature and the common techniques used in plant anatomy. The species presents leguminous fruit; seeds with pleurogram, average dimensions of 51.21, 21.33, and 2.09 mm length, width, and thickness, respectively; and seedlings with eophyll and pinnate metaphylls, cordiform, phanerocotylar germination, epigaeous, and foliaceous. Eophylls and metaphylls present uniseriate epidermis, collateral and dorsiventral vascular bundle. The morphological characteristics may help in field identification and in the identification of young plants, aiding the production of seedlings of this species. Furthermore, anatomically, the hypocotyl has no striking differences from the root.

Study on Grinding Force of High Volume Fraction SiCp/Al Composites with Rotary Ultrasonic Vibration Grinding

2014 ◽  
Vol 1027 ◽  
pp. 48-51 ◽  
Author(s):  
Dao Hui Xiang ◽  
Yu Long Zhang ◽  
Guang Bin Yang ◽  
Song Liang ◽  
Yan Feng Wang ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Material Removal ◽  
Volume Fraction ◽  
High Volume ◽  
Grinding Force ◽  
High Volume Fraction ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Grinding Parameters ◽  
Ultrasonic Grinding

High volume fraction SiCp/Al composites were grinded in rotary ultrasonic vibration aided grinding in this experiment, exploring the effects of different grinding parameters (grinding depth, grinding wheel speed, feed rate) on grinding force and the material removal mechanism with ultrasonic grinding. The results showed that grinding force of ultrasonic grinding is lower than the ordinary grinding in the same grinding parameters. Studying on material removal mechanism of ultrasonic vibration grinding is bound to have important theoretical and practical significance for the improvement of grinding processes and the development of mechanical according to the advantages of grinding and ultrasonic machining. Keywords: High volume fraction SiCp/Al composites; ultrasonic grinding; grinding force

Erynia pieris (Zygomycetes: Entomophthoraceae), a new pathogen of Pieris rapae (Lepidoptera: Pieridae): description, host range, and notes on Erynia virescens

1984 ◽  
Vol 62 (4) ◽  
pp. 653-663 ◽  
Author(s):  
Zengzhi Li ◽  
Richard A. Humber
Keyword(s):  
Heliothis Virescens ◽  
Trichoplusia Ni ◽  
Pieris Rapae ◽  
Heliothis Zea ◽  
Potato Leafhopper ◽  
Width Ratio ◽  
Laboratory Studies ◽  
Spodoptera Eridania ◽  
Length Width ◽  
The Common

Erynia pieris Li & Humber (Entomophthorales: Entomophthoraceae) is described for a fungus originally isolated from Pieris rapae (Lepidoptera: Pieridae). The fungus grows and sporulates well on standard mycological media. Primary conidia are ovoid to obovoid, 21–33 × 11–24 μm (averaging 26 × 16 μm, with a length/width ratio of 1.60), uninucleate, bitunicate, and forcibly discharged from bifurcate or irregularly branched conidiophores. Secondary through quaternary conidia are more nearly globose than primary conidia. Nuclei contain prominent, readily stained chromosomal granulations. Cystidia emerge from the host body before the conidiophores, are only slightly thicker than conidiophores at the base, and taper to a blunt apex. Rhizoids are monohyphal on lepidopterans, are little thicker than vegetative hyphae, and have no discoid terminal holdfast; rhizoidal morphology varies considerably between lepidopterous and nonlepidopterous hosts. No resting spores were observed. Laboratory studies demonstrated the pathogenicity of cultures of this fungus on several other lepidopterans (Estigmene acrea, Heliothis zea, Heliothis virescens, Trichoplusia ni, Spodoptera eridania). on the common housefly (Musca domestica), and on potato leafhopper (Etnpoasca fabae). Erynia virescens (Thax.) Remaudière & Hennebert is emended and compared with E. pieris; both species are assigned to Erynia subg. Furia (Batko) Li & Humber, comb. nov. Furia differs from other Erynia subgenera by the presence of cystidia as thick as conidiophores and of rhizoids no thicker than vegetative hyphae and having no differentiated terminal holdfasts, and by the absence of secondary capilliconidia.

Investigation on surface residual stress distribution and evaluation of engineering ceramics in rotary ultrasonic grinding machining

2016 ◽  
Vol 231 (15) ◽  
pp. 2773-2782 ◽  
Author(s):  
SL Wei ◽  
H Zhao ◽  
JT Jing ◽  
FH Yun ◽  
XL Li
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Tolerance ◽  
Surface Integrity ◽  
Residual Stress Distribution ◽  
Distribution Model ◽  
Surface Residual Stress ◽  
Machined Surface ◽  
Engineering Ceramics ◽  
Ultrasonic Grinding

Residual stress of engineering ceramics is one of surface integrity evaluation indexes affecting the parts’ strength properties. Rotary ultrasonic grinding machining is the most powerful machining method for engineering ceramics with better surface integrity. The residual stress field distribution is changed due to micro cracks which are inevitable in the process. A residual stress distribution model of machined surface micro crack tip has been established in the paper. And the experimental results enable us to obtain surface residual stress distribution of engineering ceramics in rotary ultrasonic grinding machining. Then, we propose an evaluation parameter called confidence stress tolerance to evaluate surface residual stress characteristic. Preliminary results indicate that surface residual stress distribution is in line with the normal distribution. Confidence stress tolerance is an effective parameter to improve the evaluation reliability. Furthermore, precision and affecting factors of confidence stress tolerance evaluation have also been investigated.

Study on Surface Quality of Nano ZrO2 Ceramics in Grinding by the Aid of Ultrasonic Vibration

2006 ◽  
Vol 315-316 ◽  
pp. 190-194 ◽  
Author(s):  
Dao Hui Xiang ◽  
Y.P. Ma ◽  
Bo Zhao ◽  
Ming Chen
Keyword(s):  
Residual Stress ◽  
Ultrasonic Vibration ◽  
High Efficiency ◽  
X Ray Diffraction ◽  
Ultrasonic Grinding ◽  
Surface Character ◽  
Excellent Mechanical Property ◽  
Finished Surface ◽  
Conventional Grinding

Nano ceramics possesses excellent mechanical property and physical characteristics in contrast to conventional engineering ceramics, so it has tremendous application prospect. Adopting ultrasonic composite processing we describe the influences of grinding speed, grinding depth, wheel granularity and no-spark grinding times on the surface roughness of nano ZrO2 ceramics. By means of SEM and AFM the surface character and critical ductile grinding depth of nano ZrO2 ceramics in the condition of conventional and ultrasonic grinding are also discussed. At last, the residual stress of surface and crystalline phase transformation under the condition of conventional grinding and ultrasonic vibration grinding were analyzed by X-ray diffraction. The research indicated that ultrasonic vibration grinding could obtain nano finished surface with high efficiency. The residual stress of nano ZrO2 ceramics surface is determined much by different grinding styles.

scholarly journals SHIP-GENERATED WAVES OVER A COMPLEX BATHYMETRY

2018 ◽  
pp. 35
Author(s):  
Björn Almström ◽  
Magnus Larson ◽  
Lars Granath ◽  
Hans Hanson
Keyword(s):  
Numerical Models ◽  
Water Levels ◽  
Empirical Formulas ◽  
Wave Regime ◽  
Ship Waves ◽  
Ship Wave ◽  
Energy Environment ◽  
Length Width ◽  
Stockholm Archipelago ◽  
New Formula

Problems related to shipping have increased worldwide during the last decades as a result of more traffic travel-ling at higher speeds and using larger vessels. When ships move in a restricted fairway they generate primary (drawdown) and secondary (transverse and divergent) waves (Bertram 2000) that often cause adverse impact to adjacent shores. An example of this is the Furusund fairway in Sweden, which since the 1980’s has experienced increased traffic and larger ships. This has resulted in a loss of natural fine sediment habitats along the shores as well as structural damages to piers and jetties (Granath 2015). Furusund is an important fairway into Stockholm, the capital of Sweden, and is located about 25 km north of the city within the Stockholm archipelago. It is mainly trafficked by large ferries (length/width/draft: 200x30x7m). The wind-wave regime in the fairway can be described as a low-energy environment, due to the short fetches and no swell. Hence, ship waves have a significant impact on the shores in terms of bed and bank erosion. This study aims at determining the primary ship wave characteristics and their relationship to ship properties and bathymetric conditions in the Furusund fairway. Measured water levels were collected for this purpose during three months at three locations. Existing empirical formulas for drawdown are evaluated based on the measurements and compared with a new formula derived for the specific fairway. The results are used for designing nature-based protection against ship-generated waves along the shores and to validate analytical and numerical models that can be employed for ship wave generation and propagation.

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