1 The Problem of Instantaneous Rates of Change The concept of the instantaneous rate of change of some physical quantity, position most strikingly, poses a significant philosophical dilemma. Notoriously, Zeno argued, in his arrow paradox, that the very concept of an instantaneous rate of change in position is both unavoidable in the explanation of motion and incoherent. Recently worries about i...

BACKGROUND The systolic variation of mitral regurgitation (MR) is a pitfall in its quantification. Current recommendations advocate using quantitative echocardiographic techniques that account for this systolic variation. While prior studies have qualitatively described patterns of systolic variation no study has quantified this variation. METHODS This study includes 41 patients who underwent...

This article reports the effects of various artificial aging methods and lubrication modes (dry, mist, wet) on the recorded cutting forces and chip morphology in drilling Al-Si-Mg (A356) cast alloys. In the course of this work, the work part sampled were as-received alloy (T0), solution heat-treated alloy (SHT) and then aged alloys at 155°C, 180°C, and 220°C (T4, T6, T61, T7), respectively. The...

A judicious choice of insert material, tool geometry and cutting conditions can make hard turning produce better surfaces than grinding. In the present study, an attempt has been made to investigate the effect of cutting tool materials on cutting forces (feed force, thrust force and cutting force) in finish hard turning of AISI D2 cold work tool steel. In conclusion of the results obtained with...

To investigate fluctuations in the wavefront aberrations of the eye and their relation to pulse and respiration frequencies we used a wavefront sensor to measure the dynamics of the Zernike aberrations up to the polynomial fourth radial order. Simultaneously, the subject's pulse rate was measured, from which the instantaneous heart rate was derived. We used an auto-regressive process to derive ...

In this study, the application of gray relational analysis (GRA) and Taguchi method in multi-criteria process parameters selection of turning operation has been investigated. The process responses under study are material removal rate (MRR) and surface roughness (SR); in turn, the input parameters include cutting speed, feed rate, depth of cut and nose radius of the cutting tool. The proposed a...

Many variations exist of yield curve modeling based on the exponential components framework, but most do not consider the generating process of the error term. In this paper, we propose a method of yield curve estimation using an instantaneous error term generated with a standard Brownian motion. First, we add an instantaneous error term to Nelson and Siegel’s instantaneous forward rate model [...

turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as it offers attractive benefits in terms of lower equipment costs, shorter set up time, fewer process setups, higher material removal rate, better surface quality and elimination of cutting fluids compared to cylindrical grinding. in order to obtain desired surface quality by machining, prope...