Mechanism of EDM Intensification at Ultrasound Application

2021 ◽  
Vol 410 ◽  
pp. 21-27
Author(s):  
Andrey A. Gruzdev ◽  
Yuriy A. Morgunov ◽  
Boris P. Saushkin
Keyword(s):  
Small Diameter ◽  
Multiphase Medium ◽  
Bottom Part ◽  
Interelectrode Gap ◽  
Medium Flow ◽  
Cavitation Region ◽  
Cumulative Jets ◽  
Ultrasound Application ◽  
Side Gap ◽  
The Impact

This paper considers some theoretical provisions on the impact ultrasonic mechanical vibrations have on the throughput of an electroerosive piercing of small-diameter holes. The approximate estimates confirm the hypothesis that the cumulative jets mechanism makes the greatest contribution to the intensification of a multiphase medium flow in the interelectrode gap. A model is proposed for a periodic localization of the cavitation region in the bottom part of the annular side gap. It allows explaining the occurrence of a multiphase medium flow during hole processing.

scholarly journals Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1015
Author(s):  
Antonio Bulum ◽  
Gordana Ivanac ◽  
Eugen Divjak ◽  
Iva Biondić Špoljar ◽  
Martina Džoić Dominković ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Large Diameter ◽  
Small Diameter ◽  
Shear Wave Elastography ◽  
Lesion Size ◽  
Ultrasound Elastography ◽  
Breast Lesions ◽  
Malignant Breast ◽  
The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

An Investigation of the Vibration Testing Method for Small Diameter Endmills

2014 ◽  
Vol 625 ◽  
pp. 134-139
Author(s):  
Takenori Ono
Keyword(s):  
Small Diameter ◽  
Milling Process ◽  
Modal Parameters ◽  
Vibration Testing ◽  
Function Generator ◽  
Testing Method ◽  
Milling Tool ◽  
Compliance Curve ◽  
Vibration Tests ◽  
The Impact

This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

scholarly journals Impact of Tracheal Tube on Swallowing in Post-Operative Head and Neck Cancer Patients: Scintigraphic Analysis

Dysphagia ◽  
2020 ◽  
Author(s):  
Jacopo Galli ◽  
Maria Raffaella Marchese ◽  
Tiziana Di Cesare ◽  
Laura Tricarico ◽  
Giovanni Almadori ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Cancer Patients ◽  
Tracheal Tube ◽  
Transit Time ◽  
Neck Cancer ◽  
Retention Index ◽  
Small Diameter ◽  
Swallowing Rehabilitation ◽  
The Impact

AbstractDysphagia is common in tracheostomized patients who underwent head and neck surgery for cancer treatment. The objective of this study was to evaluate, by means of oropharyngoesophageal scintigraphy (OPES), the impact of an occluded tracheal tube (TT) on swallowing in patients treated for head and neck cancer before hospital discharge, to provide further information to the benefit of out-patient care management. From October 2018 to November 2019, we enrolled 19 tracheostomized patients (6 females and 13 males; mean age 61 years) who underwent primary surgical resection of head and neck tumor and swallowing rehabilitation during hospitalization. All subjects underwent a double-standard OPES, one with occluded tracheal tube and the other without TT, with their tracheal stoma being closed directly by a plaster. For each study, we assessed and compared the following quantitative parameters: oral transit time (OTTsec), pharyngeal transit time (PTTsec), esophageal transit time (ETTsec), oral retention index (ORI%), pharyngeal retention index (PRI%), esophageal retention index (ERI%), and aspiration percentage (AP%). The mean values of OTT, PTT, ORI%, PRI%, and ERI% were abnormal during OPES both with TT and without TT and did not statistically differ between the two tests (p > 0.05). Aspiration was detected in 4 cases out of 19 (21.05%) cases during OPES with TT and in 4/19 (21.05%) cases without TT who showed a mean AP% of 11.4% and 11.5% respectively (p > 0.05). Patients with abnormal AP% (> 0%) during OPES with TT showed aspiration signs without TT. Our study showed that the mere presence of a closed tracheal tube does not impact significantly the oropharyngeal transit of bolus during swallowing. This result suggests the possibility to maintain a small-diameter occluded tracheal tube in place for the postsurgical management of head and neck cancer patients.

scholarly journals Simulation of the Impact of Ionized Impurity Scattering on the Total Mobility in Si Nanowire Transistors

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 124 ◽  
Author(s):  
Toufik Sadi ◽  
Cristina Medina-Bailon ◽  
Mihail Nedjalkov ◽  
Jaehyun Lee ◽  
Oves Badami ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Small Diameter ◽  
Golden Rule ◽  
Impurity Scattering ◽  
Boltzmann Transport ◽  
Nanowire Transistors ◽  
Scattering Mechanisms ◽  
Relaxation Time Approximation ◽  
Ionized Impurity Scattering ◽  
The Impact

Nanowire transistors (NWTs) are being considered as possible candidates for replacing FinFETs, especially for CMOS scaling beyond the 5-nm node, due to their better electrostatic integrity. Hence, there is an urgent need to develop reliable simulation methods to provide deeper insight into NWTs’ physics and operation, and unlock the devices’ technological potential. One simulation approach that delivers reliable mobility values at low-field near-equilibrium conditions is the combination of the quantum confinement effects with the semi-classical Boltzmann transport equation, solved within the relaxation time approximation adopting the Kubo–Greenwood (KG) formalism, as implemented in this work. We consider the most relevant scattering mechanisms governing intraband and multi-subband transitions in NWTs, including phonon, surface roughness and ionized impurity scattering, whose rates have been calculated directly from the Fermi’s Golden rule. In this paper, we couple multi-slice Poisson–Schrödinger solutions to the KG method to analyze the impact of various scattering mechanisms on the mobility of small diameter nanowire transistors. As demonstrated here, phonon and surface roughness scattering are strong mobility-limiting mechanisms in NWTs. However, scattering from ionized impurities has proved to be another important mobility-limiting mechanism, being mandatory for inclusion when simulating realistic and doped nanostructures, due to the short range Coulomb interaction with the carriers. We also illustrate the impact of the nanowire geometry, highlighting the advantage of using circular over square cross section shapes.

Electronic and structural study of hexagonal TiC nanowires: ab initio study

BIBECHANA ◽  
2018 ◽  
Vol 16 ◽  
pp. 7-14 ◽  
Author(s):  
Puspa Raj Adhikari ◽  
Om Prakash Upadhyay ◽  
Gopi Chandra Kaphle ◽  
Anurag Srivastava
Keyword(s):  
Density Functional ◽  
Small Diameter ◽  
Hexagonal Structure ◽  
Density Of State ◽  
Electronic Density ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
The One ◽  
The Impact ◽  
Bulk Structures

Nanowire are the one-dimensional nanostructure with the diameter order of one to few hundred nanometre. These structure shows unique properties other than their bulk structures. In this article, a qualitative first principle discussion of TiC nanowire is reported, indicating the impact of DFT based GGA relativistic corrections on its electronic properties. Here, we analyse   the Titanium Carbide (TiC) nanowire of hexagonal structure periodic in Z-direction with the density functional theory (DFT). The GGA with RBBE Correlation analysis of this material shows the metallic characteristics in its bulk but the electronic density of  state shows that the hybridization state are different from their bulk when the material is analysed in nanostructure form. Three structures of hexagonal TiC nanowire directed in (1,1,1) plane were analysed to explore diameter (4-18) Å dependent comparative study of electronic, stabilizing and optical property which shows unique different result counterparts to its bulk. Hexagonal TiC nanowire were found to be semiconducting with narrow band gap (0.21-0.34) eV in small diameter while metallic in higher diameter. They are comparable stables as their bulk for higher structure. Similarly, for the same investigation, the structures are cross checked by surface atom passivation to verify the reliability of the result that we found.BIBECHANA 16 (2019) 7-14

Laser Cutting of Small Diameter Nitinol Tube

2012 ◽  
Vol 729 ◽  
pp. 460-463
Author(s):  
Péter Nagy ◽  
János Dobránszky
Keyword(s):  
Laser Cutting ◽  
Applied Pressure ◽  
Small Diameter ◽  
Cutting Parameters ◽  
Development Project ◽  
Raw Material ◽  
Speed Up ◽  
Inner Diameter ◽  
Ar Gas ◽  
The Impact

In this article the complex research and development project of the laser cutting micromachining of nitinol alloys are shown. The laser cutting parameters of the 1.04 mm inner diameter and 0.1 mm wall thickness nitinol tubes are also shown. The laser cutting parameters of micromachining and the cut surface of nitinol tubes are summarized when 3 mJ pulse energy, 0.02 ms pulse duration, 6 bar Ar gas pressure, 3000 Hz frequency, 10 mm/s rotation speed and 5 mm/s2 speed-up were used. The effect of the laser cutting to the raw material is characterized by microstructural and micromechanical examinations. A detailed description is given of the energy input by laser beam machining. The pulse and the impact of the applied pressure parameters of the gas to the raw material are also shown.

scholarly journals The Capabilities of Electrodischarge Microdrilling of High Aspect Ratio Holes in Ceramic Materials

2015 ◽  
Vol 6 (3) ◽  
pp. 61-69 ◽  
Author(s):  
Sebastian Skoczypiec ◽  
Magdalena Machno ◽  
Wojciech Bizoń
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Efficiency ◽  
Ceramic Materials ◽  
Good Alternative ◽  
Discharge Voltage ◽  
Drilling Speed ◽  
Electrically Conductive ◽  
Side Gap ◽  
The Impact

Abstract In the first part of the article the review of ceramic materials drilling possibilities was presented. Among the described methods special attention is paid to electrodischarge drilling. This process have especially been predicted for machining difficult-to-cut electrically conductive materials. The second part consist of the results analysis of electrodischarge microdrilling of siliconized silicon carbide. The experiment involves the impact of current amplitude, discharge voltage and pulse time on the hole depth, side gap, linear tool wear and mean drilling speed. The results shows that electrodischarge drilling is a good alternative when machining inhomogeneous ceramic materials and gives possibility to drill high aspect ratio holes with relatively high efficiency (the drilling speed >2 mm/min).

Evaluation of Residual Stresses Induced by Repairs to Small Diameter Stainless Steel Pipe Welds

2015 ◽  
Author(s):  
Trevor G. Hicks ◽  
William R. Mabe ◽  
Jason R. Miller ◽  
John V. Mullen
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Large Diameter ◽  
Small Diameter ◽  
Steel Pipe ◽  
Limited Information ◽  
Diameter Pipe ◽  
Stainless Steel Pipe ◽  
Lower Magnitude ◽  
The Impact

Residual stresses within stainless steel pipe welds may cause or exacerbate in-service cracking. Significant investigative efforts have been devoted to the examination of piping residual stresses in large diameter piping using both finite element modeling and experimental techniques, but limited information is available for small diameter piping. Even less information is available for small diameter piping welds which have been repaired or re-worked during initial fabrication. This investigation used both experimental methods and analytical modeling to assess the impact of repair welding during initial fabrication on the residual stresses along the inner diameter (ID) of small diameter pipe specimens. The investigation showed that tensile axial residual stresses were located in the heat affected zone (HAZ) along the ID of the pipe specimens adjacent to regions which were excavated and re-welded. Such repair welds were also shown to markedly increase the magnitude of the tensile axial residual stresses for weld configurations which otherwise had lower magnitude residual stresses.

Influence of feeding damage by small mammals on tree growth and wood quality in young lodgepole pine

1993 ◽  
Vol 23 (5) ◽  
pp. 799-809 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Harry Coates ◽  
Les A. Jozsa ◽  
Paul K. Diggle
Keyword(s):  
Lodgepole Pine ◽  
Wood Quality ◽  
Ring Width ◽  
Small Diameter ◽  
Height Growth ◽  
Diameter Increment ◽  
Significant Difference ◽  
Small Diameter Trees ◽  
Severe Degree ◽  
The Impact

This study assessed the impact of feeding injuries by snowshoe hare (Lepusamericanus Erxleben) and red squirrel (Tamiasciurushudsonicus Erxleben) on diameter growth, height growth, and wood quality of juvenile lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) at Prince George and in the Cariboo Region, British Columbia. In the Prince George control stand, severe girdling damage (50–99% stem circumference) suppressed diameter and height growth of small-diameter (4.1–6.0 cm) trees, but had no effect on larger stems (6.1–8.0 cm). In the spaced stand, diameter and height increments also declined significantly with degree of partial girdling, particularly in small-diameter (3.1–5.0 cm) trees. Paradoxically, diameter increment increased significantly with degree of partial girdling in both stands at the Cariboo study area. Presumably squirrels prefer to feed on vigorous stems, and the lost growth of these trees may be substantial. There was no significant difference in amount of compression wood nor total solvent and water extractives between undamaged and damaged trees. Fiber lengths in wound-associated wood were consistently 19–21% lower than in controls. Damaged trees had greater average ring width and density than undamaged trees. The average increase in relative density of damaged over undamaged trees was 0.0343. These results suggest that a severe degree of partial girdling (which likely occurs more often in small-diameter trees) may significantly affect growth of lodgepole pine, particularly small (<5.0 cm DBH) trees.

A Literature Review of Ultrasound Technology and Its Application in Wastewater Disinfection

2008 ◽  
Vol 43 (1) ◽  
pp. 23-35 ◽  
Author(s):  
John H Gibson ◽  
Darrell Hai Nien Yong ◽  
Ramin R. Farnood ◽  
Peter Seto
Keyword(s):  
Uv Light ◽  
Scale Up ◽  
Suspended Particles ◽  
Poor Quality ◽  
Decrease Particle Size ◽  
Fundamental Information ◽  
Ultrasound Application ◽  
Ultrasound Technology ◽  
Practical Limit ◽  
The Impact

Abstract In recent years, there has been an increase in the application of ultraviolet (UV) light as an alternative to chemical disinfection technologies. However, in the case of poor quality effluents, the practical limit of UV disinfection of wastewater is dictated by disinfection-resistant, particle-associated bacteria. Although these particles may be removed by filtration, an alternative method to reduce the impact of suspended particles on disinfection efficiency is to decrease particle size using ultrasound technology. Mechanical forces exerted on particles due to the collapse of cavitation bubbles created by sonication break suspended particles into small fragments. In this paper, a critical review of ultrasound application for wastewater treatment is presented with emphasis on disinfection. Much of the work in this area remains at the laboratory scale. As a result, there is a need for fundamental information regarding the effect of sonication on the kinetics of disinfection and interaction of ultrasound with suspended particles. Such information is necessary for process engineering, design, and scale-up of ultrasound systems.

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