scholarly journals Peculiarities in use of cutting- electromotive force signal under conditions of computer-aided machine manufacturing

2016 ◽  
Vol 1 (6) ◽  
pp. 21-27 ◽  
Author(s):  
Александр Сергеев ◽  
Aleksandr Sergeyev ◽  
Александр Плотников ◽  
Aleksandr Plotnikov ◽  
Жанна Тихонова ◽  
...  
Keyword(s):  
Electromotive Force ◽  
Chemical Elements ◽  
Geometrical Parameters ◽  
Complex Approach ◽  
Computer Aided ◽  
Force Signal ◽  
Natural Thermocouple ◽  
Metallurgical Processes ◽  
Terminal Pair

In the paper there is considered a problem of properties heterogeneity in a terminal pair under conditions of computer-aided manufacturing. It is emphasized that this circumstance results in decrease of stability and quality of machining on the whole. The existence of tolerances for the content of chemical elements in steel is caused by a complexity in control of metallurgical processes. It is offered to use a parameter of thermo-electromotive force of a terminal pair “tool-blank” obtained in strictly definite modes of a calibrating cut for the further definition and optimization of cutting modes for machining. Drawbacks and possible variants for their solution at the realization of a method to measure cutting-electromotive force under production conditions are emphasized. A complex approach to the assessment of the influence of cutter geometrical parameters and technological factors of production upon the value of a thermo-electromotive force signal of a natural thermocouple “tool-part” is presented. It is established experimentally the influence of the antiwear coating state upon a thermo-electromotive force signal.

A Comprehensive Computational Study on OCH+-Rg (Rg = He, Ne, Ar, Kr, Xe) Complexes

2003 ◽  
Vol 68 (3) ◽  
pp. 489-508 ◽  
Author(s):  
Yinghong Sheng ◽  
Jerzy Leszczynski
Keyword(s):  
Computational Study ◽  
Relativistic Effects ◽  
Dft Method ◽  
Basis Set ◽  
Rare Gas ◽  
Geometrical Parameters ◽  
Minor Effect ◽  
Dissociation Energies ◽  
Equilibrium Geometries

The equilibrium geometries, harmonic vibrational frenquencies, and the dissociation energies of the OCH+-Rg (Rg = He, Ne, Ar, Kr, and Xe) complexes were calculated at the DFT, MP2, MP4, CCSD, and CCSD(T) levels of theory. In the lighter OCH+-Rg (Rg = He, Ne, Ar) rare gas complexes, the DFT and MP4 methods tend to produce longer Rg-H+ distance than the CCSD(T) level value, and the CCSD-calculated Rg-H+ bond lengths are slightly shorter. DFT method is not reliable to study weak interaction in the OCH+-He and OCH+-Ne complexes. A qualitative result can be obtained for OCH+-Ar complex by using the DFT method; however, a higher-level method using a larger basis set is required for the quantitative predictions. For heavier atom (Kr, Xe)-containing complexes, only the CCSD method predicted longer Rg-H+ distance than that obtained at the CCSD(T) level. The DFT method can be applied to obtain the semiquantitative results. The relativistic effects are expected to have minor effect on the geometrical parameters, the H+-C stretching mode, and the dissociation energy. However, the dissociation energies are sensitive to the quality of the basis set. The nature of interaction between the OCH+ ion and Rg atoms was also analyzed in terms of the interaction energy components.

scholarly journals Influence of Sequential CAD/CAM Milling on the Fitting Accuracy of Titanium Three-Unit Fixed Dental Prostheses

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1401
Author(s):  
Doo-Bin Song ◽  
Man-So Han ◽  
Si-Chul Kim ◽  
Junyong Ahn ◽  
Yong-Woon Im ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Computer Aided Design ◽  
Dental Prostheses ◽  
Computer Aided ◽  
Cad Cam ◽  
Fixed Dental Prostheses ◽  
Gap Data ◽  
Aided Design ◽  
Fitting Accuracy

This study investigated the fitting accuracy of titanium alloy fixed dental prostheses (FDP) after sequential CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) fabrication. A three-unit FDP model connecting mandibular second premolars and molars was prepared and scanned to fabricate titanium FDPs by CAD/CAM milling. A total of six FDPs were sequentially milled in one titanium alloy disk using a new set of burs every time (n = 4). The fitting accuracy of FDPs was mesiodistally evaluated by a silicone replica technique and the measurement was triplicated at four different locations: MO (marginal opening), MG (marginal gap), AG (axial gap), and OG (occlusal gap). Data were statistically analyzed using ANOVA and Tukey’s HSD test. The fitting accuracy of PMMA (polymethyl methacrylate) FDPs milled using the worn or new bur were evaluated by the same procedure (n = 6). The mean dimensions of titanium FDP for all measuring positions, except for AG, were significantly increased from the third milling. However, no difference was noted between the first FDP and the second FDP milled with the same set of burs. Severe edge chippings were observed in all milling burs. Detrimental effects of the worn burs on the fitting accuracy were demonstrated in the CAD/CAM-milled PMMA FDP. The results recommend proper changing frequency of cutting burs to achieve the quality of fit and predictable outcomes for dental CAD/CAM prostheses.

Structure of InAs Quantum Dots in Si Matrix Investigated by High Resolution Electron Microscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
N. D. Zakharov ◽  
P. Werner ◽  
V. M. Ustinov ◽  
A.R. Kovsh ◽  
G. E. Cirlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Critical Thickness ◽  
High Resolution Electron Microscopy ◽  
Geometrical Parameters ◽  
Inas Quantum Dots ◽  
Temperature Growth ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTQuantum dot structures containing 2 and 7 layers of small coherent InAs clusters embedded into a Si single crystal matrix were grown by MBE. The structure of these clusters was investigated by high resolution transmission electron microscopy. The crystallographic quality of the structure severely depends on the substrate temperature, growth sequence, and the geometrical parameters of the sample. The investigation demonstrates that Si can incorporate a limited volume of InAs in a form of small coherent clusters about 3 nm in diameter. If the deposited InAs layer exceeds a critical thickness, large dislocated InAs precipitates are formed during Si overgrowth accumulating the excess of InAs.

scholarly journals Simulation of rod vibrations process with an independent pendular suspension and vertical stabilization system

2018 ◽  
Vol 56 (4) ◽  
pp. 469-480
Author(s):  
I. S. Kruk ◽  
A. A. Tiunchik ◽  
V. Romanyuk
Keyword(s):  
Technological Process ◽  
Initial Conditions ◽  
Vertical Movement ◽  
Design Stage ◽  
Geometrical Parameters ◽  
Stabilization System ◽  
Special Approach ◽  
Rod Structures ◽  
Design And Testing

Continuous improvement of field sprayer design aimed at performance increase by increasing the working width, requires a special approach to ensure reliability of the supporting rod structure and quality of technological process. The question of rod vibrations, which arise when the driving systems copy field rough surface and abrupt changes in speed of the unit, remains topical. At the design stage of supporting structures of the rods, special attention is paid to the substantiation of its geometrical parameters in the longitudinal and transverse sections; studies of changes in the characteristics of vertical and horizontal vibrations, taking into account the method of the rod hanging and the system used for its stabilization. This allows to ensure the reliability of the rod design and the required quality of the technological process. The article proposes construction of the rod independent pendulum suspension on the sprayer frame and its stabilization system based on the use of damping elements. The analytical studies sequence system was developed for rod vibrations analysis, depending on initial conditions, parameters and characteristics of the used damping elements, under which they are effectively damped. It is shown that at certain numerical values of the geometrical parameters of the rod, the suspension and vibrations damping methods, not only the numerical values of the functions are changed, but also the functions themselves that describe the process of the rod's vertical movement, including cases of resonance. The obtained theoretical results can be used for design and testing of machines with rod working units and allow, at design stages, to simulate the process of movement of various rod structures from external excitatory forces, and to determine patterns of changes in the characteristics of damped vibrations using different damping elements and their installation parameters.

Computer‐aided selective production of low-resistance NiP and NiCuP layers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Piotr Kowalik ◽  
Edyta Wróbel
Keyword(s):  
Low Temperature ◽  
Computer Program ◽  
Design Methodology ◽  
Surface Resistance ◽  
Temperature Coefficient Of Resistance ◽  
Ceramic Substrates ◽  
Content Type ◽  
Computer Aided ◽  
Chemical Metallization

Purpose This paper aims to present the possibility of computer-aided technology of chemical metallization for the production of electrodes and resistors based on Ni-P and Ni-Cu-P layers. Design/methodology/approach Based on the calculated parameters of the process, test structures were made on an alumina substrate using the selective metallization method. Dependences of the surface resistance on the metallization time were made. These dependencies take into account the comparison of the calculations with the performed experiment. Findings The author created a convenient and easy-to-use tool for calculating basic Ni-P and Ni-Cu-P layer parameters, namely, surface resistance and temperature coefficient of resistance (TCR) of test resistor, based on chemical metallization parameters. The values are calculated for a given level of surface resistance of Ni-P and Ni-Cu-P layer and defined required range of changes of TCR of test resistor. The calculations are possible for surface resistance values in the range of 0.4 Ohm/square ÷ 2.5 Ohm/square. As a result of the experiment, surface resistances were obtained that practically coincide with the calculations made with the use of the program created by the authors. The quality of the structures made is very good. Originality/value To the best of the authors’ knowledge, the paper presents a new, unpublished method of manufacturing electrodes (resistors) on silicon, Al2O3 and low temperature co-fired ceramic substrates based on the authors developed computer program.

Trust in Computer-Mediated Communications

2009 ◽  
pp. 2118-2131
Author(s):  
Susan K. Lippert
Keyword(s):  
Common Factors ◽  
Factors Affecting ◽  
Computer Mediated ◽  
Computer Aided ◽  
Computer Mediated Communications

This chapter explores the concepts of trust as they relate to computer-aided communications. The author defines trust for interpersonal and for inanimate technology, identifies common factors affecting quality of meaning in communication, and identifies ways businesses can foster and enhance trust independent of the medium of communication.

scholarly journals Computer-Aided Rehabilitation Supported by Zygomatic Implants: A Cohort Study Comparing Atrophic with Oncologic Patients after Five Years of Follow-Up

2020 ◽  
Vol 9 (10) ◽  
pp. 3254 ◽  
Author(s):  
Gerardo Pellegrino ◽  
Francesco Basile ◽  
Daniela Relics ◽  
Agnese Ferri ◽  
Francesco Grande ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Clinical Success ◽  
Clinical Success Rate ◽  
Zygomatic Implants ◽  
Oncologic Patients ◽  
Computer Aided ◽  
Prosthetic Complications ◽  
Maxillary Atrophy

The aim of this study was to evaluate the survival and clinical success rate, complications, and patients’ quality of life after computer-aided rehabilitation supported by zygomatic implants in cases of severe maxillary atrophy (ten patients) and in bone defects in oncologic patients (ten patients). All patients underwent computer-aided planning and surgery. Seventy-three zygomatic implants were placed. The mean follow-up period was 39.9 months. Implant survival and clinical success rate, the effectiveness of planning the implant length, biological and prosthetic complications, and the quality of life were evaluated. The five-year implant survival rate for patients with maxillary atrophy and oncologic patients was 97.4% and 96.7%, respectively. The prosthetic survival rate was 100%. Two implant failures occurred in the first year. One implant failure was observed in each group. Minor biological and prosthetic complications occurred in both groups without significant differences. All complications were managed without affecting the treatment. The quality of life increased by 71.3% in the atrophic group and by 82.9% in the oncologic group. Zygomatic implant rehabilitation seems to be a reliable technique for patients with maxillary atrophy and for oncologic patients. The three-dimensional computer-aided approach allows the surgeon to plan the surgery and increase its predictability. Early prosthesis loading certainly allows for better functional outcomes.

New Developments in PC-Based Powder Data Retrieval Programs

1993 ◽  
Vol 37 ◽  
pp. 117-121
Author(s):  
Ron Jenkins
Keyword(s):  
Personal Computer ◽  
Reference Data ◽  
Data Retrieval ◽  
Phase Identification ◽  
Cd Rom ◽  
Computer Aided ◽  
Automatic Search ◽  
Manual Methods ◽  
Multi Phase

While most contemporary methods of qualitative analysis of multi-phase materials are still based on the classic Search/Match/Identify process developed by Hanawalt, Rinn and Frevel in the 1930s, during the past 10 years or so the personal computer, with associated CD-ROM storage, has made a dramatic impact on the ways in which classical procedures are being implemented. Until recently, most of the commercial mainframe and PC based software packages for qualitative phase identification have been designed to implement a fully automatic search/matching sequence. All of the major instrument suppliers now offer such programs as part of their Automated Powder Diffractometer (APD) packages. While these programs are extremely useful, the success of their application to a specific problem is critically dependent on the quality of both experimental data and reference data. Until the problems arising from comparing variable quality experimental and reference data are completely understood, it appears that there will continue to be an interest in user-inter active (computer-aided) manual methods of search/matching. This paper explores the use of the personal computer in the area of computer-aided search/matching

scholarly journals Cholesterol-loaded cyclodextrin plus trehalose improves quality of frozen-thawed ram sperm

2019 ◽  
Vol 64 (No. 03) ◽  
pp. 118-124 ◽  
Author(s):  
ME Inanc ◽  
S Gungor ◽  
C Ozturk ◽  
F Korkmaz ◽  
I Bastan ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Mitochondrial Membrane ◽  
Improve Quality ◽  
Progressive Motility ◽  
Computer Aided ◽  
Acrosome Integrity ◽  
Ram Sperm ◽  
Additive Control ◽  
Artificial Vagina

The objective of this study was to determine effects of supplementing Tris-based semen extenders with either cholesterol-loaded cyclodextrin (CLC) or 7-dehydrocholesterol loaded cyclodextrin (7-DCLC) plus trehalose (T) for cryopreservation of ram semen. Semen was collected with an artificial vagina from five Merino rams (2–3 years of age) during the non-breeding season. Ejaculates were pooled, divided into eight equal portions, diluted with a standard Tris-based extender containing: no additive (control); T (50 mM); or T (50 mM) + 1.5, 2.5 or 3.5 mg of either 7-DCLC or CLC. Semen was chilled from 37°C to 4°C, placed in 0.25 ml French straws, held 5 cm above liquid nitrogen for 12 minutes, then plunged into liquid nitrogen. After thawing, a computer-aided semen analyzer system (CASA) was used to assess motility, whereas plasma membrane and acrosome integrity (PMAI) and high mitochondrial membrane potential (HMMP) were assessed with flow cytometry. Sperm supplemented with 2.5 mg and 3.5 mg CLC + T had the highest (P < 0.05) total and progressive motility (65.2 ± 4.7 and 19.0 ± 1.0% respectively, mean ± SEM), albeit with no significant differences from sperm with 1.5 or 3.5 mg CLC + T. Sperm with 2.5 mg CLC + T had the highest (P < 0.05) PMAI (59.3%; not different from 3.5 mg CLC + T) and highest (P < 0.05) HMMP (64.6%; not different from 1.5 or 3.5 mg CLC + T). The lowest ALH value, 2.8 ± 0.3 µm was in the 2.5 mg 7-DCLC + T group; otherwise, there were no significant differences among groups for any other CASA end point. In conclusion, adding CLC + T to a tris-based extender optimized quality of frozen-thawed ram semen. Therefore, extenders including CLC + T have potential to improve quality of frozen-thawed ram sperm.

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