XXXVI. —On friction in machinery

Notes on Some Remedies. XXXVI. Penicillin

The COPD Pipeline XXXVI.

Contract Pharma is a publication that reviews, among other things, the pharmaceutical industry annually. Those of us who work in chronic obstructive pulmonary disease (COPD) take an interest in the source of the drugs we use and Contract Pharma brings that information to us. Each year they report the status of the top 25 pharmaceutical companies.1 For each pharma, a report lists the newly appro...

Clinical studies of induction agents. XXXVI: Ketamine.

The intravenous anaesthetic ketamine has been given to patients undergoing minor gynaecological surgery after atropine prcmedication in initial doses ranging from 1.0 to 3.0 mg/kg. The chief induction complications were hypertension and hypertonus, the incidence of which was only broadly related to dosage. Recovery of consciousness was rapid, though marred by a high incidence of delirium at all...

On Friction Compensation without Friction Model

This paper presents a new methodology for friction compensation that is not based on any friction model. This is done by using finite-terms Fourier series to approximate the friction term. Updating laws for the coefficients of the series are easily derived from a Lyapunov approach to guarantee asymptotic convergence of the tracking error. Computer simulations are then proposed in which friction...

Lecture XXXVI: Introduction to cosmological perturbations

We begin by considering a spatially flat FRW universe, which has background metric ds = a(η)(−dη + δijdxdx). (1) Note here that we use the conformal time η instead of t as our time coordinate, for consistency with the rest of cosmological perturbation theory. In this case, the spatial metric is γij(η, x ) = a(η)δij . We will also introduce the conformal Hubble rate, H(η) = d ln a(η) dη = aH (2)...