The Quadratic Curve and the Trajectory in the Shear Zone in Metal Cutting

1975 ◽  
Vol 97 (3) ◽  
pp. 1105-1111 ◽  
Author(s):  
J. H. L. The
Keyword(s):  
Shear Zone ◽  
Metal Cutting ◽  
Fine Grid ◽  
Simple Method ◽  
Quadratic Curve ◽  
Parallel Lines ◽  
Order Of Magnitude ◽  
Experimental Errors ◽  
Best Fit ◽  
Cutting Speeds

The quadratic curve was investigated as an approximation of the streamline in the steady-state shear zone during metal cutting. Experimentally, a very fine grid of parallel lines (spacing 25 μ, depth 6 μ) was inscribed on the work face through a simple method which eliminates the problems associated with the photographic and etching techniques. Quick stops were taken using an explosive device for cutting speeds of 50, 150, and 250 m/min. Next, several quadratic curves were fitted to the experimental streamline, which was measured at six points along its path. The two tangents at the start and end of the shear zone were also measured. Of the three types (ellipse, hyperbola, and parabola) studied, the hyperbola and, specifically, the rectangular hyperbola (x2 − y2 = c2) gave the best fit with experiment. Trajectory deviation in these cases is <1 percent and the strain-rate deviation is <6 percent. These are in the order of magnitude of the experimental errors.

Temperature Dependence of the Self-Assembled Styrene Based Random Ionomers in Aqueous Solution

2003 ◽  
Vol 775 ◽  
Author(s):  
Sung-Hwa Oh ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
Hyang-Rim Oh ◽  
Jeong-A Yu
Keyword(s):  
Partition Coefficients ◽  
Room Temperature ◽  
Aqueous Media ◽  
The Self ◽  
Spectroscopic Methods ◽  
Ion Content ◽  
Repeat Units ◽  
Notable Effect ◽  
Order Of Magnitude ◽  
Experimental Errors

AbstractSolution behaviors of poly(styrene-co-sodium methacrylate) were studied by fluorescence spectroscopic methods using pyrene as a probe. The mol% of methacrylate was in the range 3.6–9.4. Water and N,N-dimethylforamide(DMF) mixture was used as a solvent (DMF/water = 0.2 mol %). The critical micelle (or aggregation) concentrations of ionomers and the partition coefficients of pyrene were obtained the temperature range 10–80°C. At room temperature, the values of CMCs (or CACs) were in the range 4.7 ×10-6 5.3 ×10-6 g/mL and we could not find any notable effect of the content of ionic repeat units within the experimental errors. Unlike CMCs, as the ion content increased, partitioning of pyrene between the hydrophobic aggregates and an aqueous media decreased from 1.5 ×105 to 9.4 ×104. As the temperature increased from 10 to 80 °C, the values of CMCs increased less than one order of magnitude. While, the partition coefficients of pyrene decreased one order of magnitude and the effect of the ion content became negligible.

Studies of calcium-45 desaturation from kidney slices in flow-through chambers

1978 ◽  
Vol 234 (1) ◽  
pp. R34-R38
Author(s):  
T. Uchikawa ◽  
A. B. Borle
Keyword(s):  
Kinetic Parameters ◽  
Rat Kidney ◽  
Kidney Cells ◽  
Tissue Slices ◽  
Kidney Slices ◽  
System A ◽  
Order Of Magnitude ◽  
Exponential Equations ◽  
Flow Through ◽  
Best Fit

This paper describes a method to measure calcium fluxes and calcium exchangeable pools in tissue slices by continuous perifusion in flow-through chambers. 45Ca desaturation from rat kidney slices can be analyzed as in an open three-compartment catenary system. A set of equations is given to calculate all the relevant kinetic parameters from the triple exponential equations which best fit the desaturation curves. The results show that the kinetic parameters obtained in kidney slices by this new method are in the same order of magnitude as those previously observed in cultured monkey kidney cells.

Influence of Free Surface Environment on the Shear Zone in Metal Cutting

1966 ◽  
Vol 181 (1) ◽  
pp. 687-705 ◽  
Author(s):  
P. L. Barlow
Keyword(s):  
Free Surface ◽  
Carbon Tetrachloride ◽  
Strain Hardening ◽  
Shear Zone ◽  
Chemical Reaction ◽  
Cutting Forces ◽  
Metal Cutting ◽  
The Body ◽  
Surface Barrier ◽  
Rehbinder Effect

It has previously been suggested that the reduction in cutting forces obtained by the presence of fluids such as CCl4 on the backface or free surface of the forming chip was due to diffusion of the fluid into the body of the chip in the region of the shear zone. In the present work, experiments with carbon tetrachloride tagged with carbon-14 and with carbon tetrachloride tagged with chlorine-36 were performed with the object of assessing the extent of diffusion of lubricants into the chip when present on the free surface only. The results obtained disprove former hypotheses and suggest that the reduced cutting force is due solely to chemical reaction at the surface of the chip. Confirmation of the sensitivity of the surface of the deforming shear zone to change in surface condition was obtained by removing metal from this region by an electropolishing technique during slow speed cutting. By varying the electropolishing conditions increased or decreased cutting forces could be obtained. It is proposed that the result both of chemical reaction at the surface and of surface removal is to reduce the strain-hardening rate of the metal undergoing shear by reducing the surface barrier to the flow of dislocations out of the metal. The association of the surface reaction of carbon tetrachloride with a change in the strain-hardening characteristics of the metal in the shear zone leads to a classification of the backface phenomenon as a Rehbinder effect and enables this effect to be more closely defined than was hitherto possible. Evidence is also presented which indicates that the backface effect does not contribute to the reduction in cutting forces during rakeface lubrication and is therefore unimportant in practice where flood lubrication of the cutting region invariably occurs.

Expected Improvement in the Determination of G Using an X Pendulum

1997 ◽  
Vol 12 (11) ◽  
pp. 1967-1974 ◽  
Author(s):  
Kazuaki Kuroda ◽  
Mark A. Barton ◽  
Atsushi Onae ◽  
Yukinobu Miki
Keyword(s):  
Gravitational Constant ◽  
New Technique ◽  
Expected Improvement ◽  
Order Of Magnitude ◽  
Experimental Errors ◽  
A New Technique ◽  
Newtonian Gravitational Constant

We propose the application of a new technique, the X pendulum, to determine the Newtonian gravitational constant G. We evaluate the likely experimental errors for configurations realizable with existing technologies and show that improvement of the accuracy by an order of magnitude or more is possible.

scholarly journals Insights into Machining of a β Titanium Biomedical Alloy from Chip Microstructures

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 710 ◽  
Author(s):  
Damon Kent ◽  
Rizwan Rahman Rashid ◽  
Michael Bermingham ◽  
Hooyar Attar ◽  
Shoujin Sun ◽  
...  
Keyword(s):  
Shear Band ◽  
Shear Zone ◽  
Biomechanical Properties ◽  
Temperature Fields ◽  
Large Strains ◽  
Shear Direction ◽  
Grain Sizes ◽  
Β Phase ◽  
Secondary Shear Zone ◽  
Cutting Speeds

New metastable β titanium alloys are receiving increasing attention due to their excellent biomechanical properties and machinability is critical to their uptake. In this study, machining chip microstructure has been investigated to gain an understanding of strain and temperature fields during cutting. For higher cutting speeds, ≥60 m/min, the chips have segmented morphologies characterised by a serrated appearance. High levels of strain in the primary shear zone promote formation of expanded shear band regions between segments which exhibit intensive refinement of the β phase down to grain sizes below 100 nm. The presence of both α and β phases across the expanded shear band suggests that temperatures during cutting are in the range of 400–600 °C. For the secondary shear zone, very large strains at the cutting interface result in heavily refined and approximately equiaxed nanocrystalline β grains with sizes around 20–50 nm, while further from the interface the β grains become highly elongated in the shear direction. An absence of the α phase in the region immediately adjacent to the cutting interface indicates recrystallization during cutting and temperatures in excess of the 720 °C β transus temperature.

Evaluation of the Service Performance of Ships

2005 ◽  
Vol 42 (04) ◽  
pp. 177-183
Author(s):  
Poul Andersen ◽  
Anne-Sophie Borrod ◽  
Hervé Blanchot
Keyword(s):  
Input Data ◽  
High Efficiency ◽  
Service Performance ◽  
The Other ◽  
Simple Method ◽  
Propulsive Efficiency ◽  
Order Of Magnitude ◽  
Time Periods

A simple method has been established for the evaluation of the service performance of ships. Input data are easily collected daily on board and transformed to a well-defined condition that makes possible the comparison between ships, for instance, sister ships, and between different time periods of voyages for the same ship. The procedure has been applied to two ships that are identical, with the only exception that one has a conventional propeller, whereas the other one is fitted with a high-efficiency propeller of the KAPPEL type. The results are obtained from a period of 2 years steaming for both vessels. They clearly confirm the increase of propulsive efficiency obtained with the KAPPEL propeller in the order of magnitude of 4%.

A Simple Method for Elastic Analysis of Grillages

1968 ◽  
Vol 12 (02) ◽  
pp. 153-159
Author(s):  
Pin-Yu Chang
Keyword(s):  
Finite Element ◽  
Plate Theory ◽  
Computer Time ◽  
Design Tool ◽  
Matrix Transformations ◽  
Simple Method ◽  
Elastic Foundations ◽  
Beam Analysis ◽  
Order Of Magnitude ◽  
Desk Calculator

The theory of beams supported by elastic foundations has been shown to be particularly well-suited to the analysis of grillage beams [1, 2, 3[.2 This theory leads to a far more general formulation regarding the types of structures amenable to analysis than that offered by the orthotropic plate theory. As compared to the methods of finite element theory, the theory of beams supported by elastic foundations decreases the computer time by an order of magnitude, thus making the analysis particularly valuable as a design tool. This paper shows that the measurement of the grillage beam analysis based upon the elastic foundation concept can be further simplified by certain matrix transformations that uncouple the deflection equations. The problem has, in fact, been simplified to such an extent that many large grillages can be analyzed with the aid of a desk calculator. Whenever comparison with results obtained from finite element methods has been possible, it has been found that, for all practical purposes, complete correlation exists.

Simplified approach to confidence limited in radioimmunassay.

1980 ◽  
Vol 26 (6) ◽  
pp. 763-765 ◽  
Author(s):  
R C Baxter
Keyword(s):  
Quality Control ◽  
Mean Value ◽  
Confidence Limits ◽  
Simple Method ◽  
Response Variable ◽  
Simplified Approach ◽  
Quadratic Curve ◽  
Wide Range ◽  
Advanced Computing ◽  
Routine Quality Control

Abstract A simple method of calculating confidence limits for radioimmunoassay data is presented. The method involves the use of the within-assay variation in dose estimate of three routine quality-control specimens, measured in repeated assays, to estimate the confidence limits for results on unknown samples. Results for control specimens are combined by calculating the unique quadratic curve fitting a graph of within-assay standard deviation vs mean value for each control. This method requires no special data accumulation or advanced computing equipment. For cortisol, lutropin, and thyroxine radioimmunoassays, confidence limits calculated in this way have been compared with those calculated from the variance of the response variable “B/B0” in repeated standard curves. Both methods agree well with actual limits observed when plasma pools containing a wide range of hormone concentrations are assayed repeatedly.

scholarly journals Investigation into Performance of Multilayer Composite Nano-Structured Cr-CrN-(Cr0.35Ti0.40Al0.25)N Coating for Metal Cutting Tools

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 447 ◽  
Author(s):  
Sergey Grigoriev ◽  
Alexey Vereschaka ◽  
Alexander Metel ◽  
Nikolay Sitnikov ◽  
Filipp Milovich ◽  
...  
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Constructional Steel ◽  
Wear Process ◽  
Layered Architecture ◽  
Process Pattern ◽  
Resistant Layer ◽  
Cutting Speeds

This paper deals with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating. It has a three-layered architecture with a nano-structured wear-resistant layer. The studies involved the investigation into the microstructure (with the use of SEM and TEM), elemental and phase composition (XRD and SAED patterns), wear process pattern in scratch testing, crystal structure, as well as the microhardness of the coating. Cutting tests of tools with the above coating were carried out in dry turning of steel 1045 at cutting speeds of vc = 200, 250, and 300 m·min−1. The comparison included uncoated tools and tools with the commercial TiN and (Ti,Al)N coatings with the same thickness. The tool with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating showed the longest tool life at all the cutting speeds under consideration. Meanwhile, a tool with the coating under study can be recommended for use in turning constructional steel at the cutting speed of vc = 250 m·min−1. At this cutting speed, a tool shows the combination of a rather long tool life and balanced wear process, without any threat of catastrophic wear.

Numerical Investigation of Heat Partition in the Primary Shear Zone in Metal Cutting

2005 ◽  
Author(s):  
Vasant Pednekar ◽  
Vis Madhavan ◽  
Amir H. Adibi-Sedeh
Keyword(s):  
Partition Coefficient ◽  
Strain Rate ◽  
Shear Zone ◽  
Metal Cutting ◽  
Plastic Material ◽  
Shear Plane ◽  
Analytical Models ◽  
Machined Surface ◽  
Element Analysis ◽  
Heat Partition

The fraction of heat generated in the primary shear zone that is conducted into the workpiece is a key factor in the calculation of the shear plane temperature and in calculating the cutting forces based on material flow stress. Accurate analytical, numerical, or experimental determination of this heat partition coefficient is not available to date. This study utilizes a new approach to obtain the heat partition coefficient for the primary shear zone using results for strain, strain rate, and temperature distribution obtained from a coupled thermo-mechanical finite element analysis of machining. Different approaches, using strain rate and equivalent strain, are used for calculating the total plastic power in the primary shear zone and the heat generated by plastic deformation below the plane of the machined surface. The heat carried away by the workpiece is obtained by calculating the heat flow by convection in regions where the conduction is expected to be small. We have used an elastic perfectly plastic material model and constant thermal properties to mimic the assumptions used in analytical models. The fraction of the total heat generated in the primary shear zone that is conducted into the machined workpiece is found and compared to the prediction of different analytical models. It is found that for most of the cutting conditions, the values of heat partition coefficient are closest to those provided by Weiner’s model.

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