Tension time index

Vassilakopoulos T, Zakynthinos S, Roussos C. The tension-time index and the liequency/tidal volume ratio are the major pathophysiologic determinants of weaning failure and success. Am J Respir Crit Care Med 1998 158 378-385. 

Abbreviations-. IPAP/EPAP, ratio of inspirat(xy positive airway pressure and expiratory positive airway pressure NP ABG, arterial blood gas 6-MWD, six-minute walking distance 6-MWT, six-minute walk test HRQL, health-related quaUty of Ufe RVEL, right ventricular ejection fraction LVEF, left ventricular ejection fraction NIPPV, noninvasive positive pressure ventilation O2, oxygen Til, tension time index. 

Sarnoff, S.J. et al.. Hemodynamic determinants of oxygen consumption of the heart with special reference to the tension-time index. Am J Physiol Legacy Content, 1957.192(1) p. 148-56. 

In several previous papers, the possible existence of thermal anomalies was suggested on the basis of such properties as the density of water, specific heat, viscosity, dielectric constant, transverse proton spin relaxation time, index of refraction, infrared absorption, and others. Furthermore, based on other published data, we have suggested the existence of kinks in the properties of many aqueous solutions of both electrolytes and nonelectrolytes. Thus, solubility anomalies have been demonstrated repeatedly as have anomalies in such diverse properties as partial molal volumes of the alkali halides, in specific optical rotation for a number of reducing sugars, and in some kinetic data. Anomalies have also been demonstrated in a surface and interfacial properties of aqueous systems ranging from the surface tension of pure water to interfacial tensions (such as between n-hexane or n-decane and water) and in the surface tension and surface potentials of aqueous solutions. Further, anomalies have been observed in solid-water interface properties, such as the zeta potential and other interfacial parameters. 

Any reference books to be used in the examination should not be bought at the last moment — books should have been used for some time because it is easier to turn the pages, as those in new books tend to stick together such minor annoyances encountered during an examination can increase the tension. In addition, get used to the newer editions of the textbooks. Practise using the indexes, appendices and footnotes and be familiar with the overall structure of the reference books used in an open-book session.)... 

There has been some controversy over the definition of creep which should be used. Traditionally, creep was defined in the rubber industry as the increase in deformation after a specified time interval expressed as a percentage of the test piece deformation at the start of that time interval. In other industries creep is normally defined as the increase in deformation expressed as a percentage of the original unstressed dimension of the test piece. Consequently, care has to be taken when comparing creep values obtained from different sources. ISO 8013 has both definitions, calling them creep index and creep increment respectively. The definition of creep increment in the standard refers to the original dimension as thickness, which would not apply to tension. ISO 8013 also defines a compliance index which is the ratio of the increase in strain to the constant applied stress. 

The proper choice of a solvent for a particular application depends on several factors, among which its physical properties are of prime importance. The solvent should first of all be liquid under the temperature and pressure conditions at which it is employed. Its thermodynamic properties, such as the density and vapour pressure, and their temperature and pressure coefficients, as well as the heat capacity and surface tension, and transport properties, such as viscosity, diffusion coefficient, and thermal conductivity also need to be considered. Electrical, optical and magnetic properties, such as the dipole moment, dielectric constant, refractive index, magnetic susceptibility, and electrical conductance are relevant too. Furthermore, molecular characteristics, such as the size, surface area and volume, as well as orientational relaxation times have appreciable bearing on the applicability of a solvent or on the interpretation of solvent effects. These properties are discussed and presented in this Chapter. 

In 113 patients undergoing general anesthesia, intravenous midazolam 15 mg slowed recovery of the twitch height after vecuronium and atracurium compared with diazepam. The recovery index was not altered (162). However, in another study in 20 patients, midazolam 0.3 mg/kg did not affect the duration of blockade, recovery time, intensity of fasciculations, or adequacy of relaxation for tracheal intubation produced by suxamethonium 1 mg/kg, nor the duration of blockade and adequacy of relaxation for tracheal intubation produced by pancuronium 0.025 mg/kg in incremental doses until 99% depression of muscle-twitch tension was obtained (161). Furthermore, in 60 patients undergoing maintenance anesthesia randomly assigned to one of six regimens (etomidate, fentanyl, midazolam, propofol, thiopental plus nitrous oxide, or isoflurane plus nitrous oxide), midazolam did not alter rocuronium dosage requirements (165). 

Chief among the interfacial properties of aqueous systems that suggest the occurrence of thermal anomalies are the following index of refraction, density, activation energy for ionic conductance, rates of surface reactions, surface tension, surface potentials, membrane potentials, heats of immersion, zeta potentials, rate of nucleation, viscous flow, ion activities, proton spin lattice relaxation times, optical rotation, ultrasonic velocity and absorption, sedimentation rates, coagulation rates, and dielectric properties. 

Since the time that study was made, a large body of experimental data has accumulated which shows that regular and predictable changes in solid-liquid contact angles result from changes in the outermost layer of atoms in the solid surface. A "wettability spectrum" has been published [14],and the utility of the "critical surface tension of wetting" as an index of solid surface energy has been well established. 

Monomer conversion can be adjusted by manipulating the feed rate of initiator or catalyst. If on-line M WD is available, initiator flow rate or reactor temperature can be used to adjust MW [38]. In emulsion polymerization, initiator feed rate can be used to control monomer conversion, while bypassing part of the water and monomer around the first reactor in a train can be used to control PSD [39,40]. Direct control of surfactant feed rate, based on surface tension measurements also can be used. Polymer quality and end-use property control are hampered, as in batch polymerization, by infrequent, off-line measurements. In addition, on-line measurements may be severely delayed due to the constraints of the process flowsheet. For example, even if on-line viscometry (via melt index) is available every 1 to 5 minutes, the viscometer may be situated at the outlet of an extruder downstream of the polymerization reactor. The transportation delay between the reactor where the MW develops, and the viscometer where the MW is measured (or inferred) may be several hours. Thus, even with frequent sampling, the data is old. There are two approaches possible in this case. One is to do open-loop, steady-state control. In this approach, the measurement is compared to the desired output when the system is believed to be at steady state. A manual correction to the process is then made, based on the error. The corrected inputs are maintained until the process reaches a new steady state, at which time the process is repeated. This approach is especially valid if the dominant dynamics of the process are substantially faster than the sampling interval. Another approach is to connect the output to the appropriate process input(s) in a closed-loop scheme. In this case, the loop must be substantially detuned to compensate for the large measurement delay. The addition of a dead time compensator can... 

Chai oil n. Mexican oil obtained from Salvia hispanica. It has excellent drying properties. A prominent characteristic of the oil is its high surface tension, which causes it to crawl , cooking at 260° C (500°F) for a short time destroys this property. Its main constituent acids may make up more than 90% of the total acids. Properties Sp gr, 0.9338/15°C refractive index, 1.4855 iodine value, 196.3 saponification value 192.2. 

---