Gauge Size Research Articles

J.-F.-B. Charrière: The man behind the “French” gauge

Joseph-Frédéric-Benoît Charrière, a 19th century Parisian maker of surgical instruments, has by virtue of his ingenuity and advanced thinking, continued to have his presence felt in medicine throughout the 20th century. His most significant accomplishment was the development of a uniform, standard gauge specifically designed for use in medical equipment such as catheters and probes. Unlike the gauge system adopted by the British for measurement of needles and intravenous catheters, Charrière's system has uniform increments between gauge sizes (113 of a millimeter), is easily calculated in terms of its metric equivalent, and has no arbitrary upper end point. Today, in the United States, this system is commonly referred to as French (Fr) sizing. In addition to the development of the French gauge, Charrière made significant advances in ether administration, urologic, and other surgical instruments, and the development of the modern syringe.

The origins of the gauge system for medical equipment.

The gauge system for sizing medical catheters and equipment is used widely around the world. Yet both its origins and its interpretation, in terms of conventional measurements, have long been obscure. The gauge, formally known as the Stubs Iron Wire Gauge, was developed in early 19th century England. Developed initially for use in wire manufacture, each gauge size arbitrarily correlates to multiples of .0010 inches. This sizing system was the first wire gauge recognized as a standard by any country (Great Britain, 1884). It was first used to measure needle sizes in the early 20th century. Today it is used in medicine to measure not only needles, but also catheters and suture wires. However, owing to the potential confusion inherent in using a gauge system, the iron wire gauge is rarely used in manufacture of nonmedical equipment.

Manual metal arc weld modelling: Part 1 Effect of process parameters on dimensions of weld bead and heat-affected zone

The properties of a weldment are determined largely by the size and distribution of microstructural regions within the weld metal and heat-affected zone (HAZ). It has been appreciated for some time that these properties may be controlled by adjusting the parameters of the welding process, although until recently this was done mainly qualitatively. Means of achieving more quantitative control are now beginning to be applied. In this paper measurements of the sizes of the weld bead and HAZ are presented for single manual metal arc weld beads. The process variables investigated were electrode type, gauge size, welding position, polarity, welding current, preheat, and welding velocity. Functional relationships between the process variables and the size of the weld bead and HAZ are determined. The generality of these relationships is examined by analysing measurements made previously on other materials. The results are discussed in terms of the theory of the welding process and, as shown in two accompanying papers, they can be used to develop models of multipass manual metal arc welding on which a practical welding procedure may be based.MST/193a

Manual metal arc weld modelling: Part 1 Effect of process parameters on dimensions of weld bead and heat-affected zone

The properties of a weldment are determined largely by the size and distribution of microstructural regions within the weld metal and heat-affected zone (HAZ). It has been appreciated for some time that these properties may be controlled by adjusting the parameters of the welding process, although until recently this was done mainly qualitatively. Means of achieving more quantitative control are now beginning to be applied. In this paper measurements of the sizes of the weld bead and HAZ are presented for single manual metal arc weld beads. The process variables investigated were electrode type, gauge size, welding position, polarity, welding current, preheat, and welding velocity. Functional relationships between the process variables and the size of the weld bead and HAZ are determined. The generality of these relationships is examined by analysing measurements made previously on other materials. The results are discussed in terms of the theory of the welding process and, as shown in two accompanying papers, they can be used to develop models of multipass manual metal arc welding on which a practical welding procedure may be based.MST/193a

Gauge Inspection Using Hough Transforms

An automatic method of inspecting the scaling accuracy of needle-type instrument gauges using a two-stage Hough transform technique is described. The system measures and verifies the relative accuracy of a gauge's response to a specified set of analog input signals. The method does not require that the gauge's position, orientation, or size be known a priori and the algorithm is very suitable for high-speed hardware implementation.

A Gauge For Measurements Of Soil-structureInterface Force Due To Explosive Loading

The paper presents some work regarding construction of a soil-structure interface gauge measuring the interface force distribution over much larger areas than possible with conventional pressure gauges. Different backfill/backpack materials surrounding buried protective structures may have different effects regarding the interface forces between the soil and structure when exposed to explosive loading. The motivation of this work is to study these effects. The gauge concept consists of a grid of uncoupled plane areas using PVDF-film sensors between two mating surfaces to measure the pressure. The gauge is described in detail. This concept is attractive because all parts are commercially available and the concept is easy to extend to large scale gauges for use in full scale explosive tests. The interface gauge is designed to measure both uniform pressure and point loads from backfill/-backpack materials. Design, necessary equipment and some experimental evaluations of the demonstration gauge are presented. INTRODUCTION It has been known for many decades that certain crystals, like quartz, generates an electrical charge across the crystal when stressed. This is called a piezoelectrical effect. The amplitude of the signal are directly proportional to the deformation of the piezoelectric material [1 ]. Today appropriately treated polyvinylidene fluoride (PVDF) exhibits piezoelectric properties suitable for a variety of applications. Piezoelectric film is a flexible, lightweight, tough plastic film commercially available in a large variety of thicknesses and areas, and its properties as a transducer includes wide frequencies and vast dynamic range. This properties make the PVDF-film appropriate as impact and shock wave sensors. The Norwegian Defence Construction Service is running a research program regarding backfill/backpack materials surrounding buried protective structures. The Transactions on the Built Environment vol 8, © 1994 WIT Press, www.witpress.com, ISSN 1743-3509 358 Structures under Shock and Impact objective of this project is to study the interaction between soil and structure subjected to explosive loading, since different backfill/backpack materials are known to impose quite different loads on a buried structure. The following requirements were essential for development of the interface gauge To measure high pressures up to 50 MPa To measure point loads and their distribution Large scale, gauge size 1 nr Be flexible, give correct results also under structural deformation To be insensitive to tough surface conditions To our knowledge, no commercial gauge is available for this purpose, and hence it was decided to develop a small scale demonstrative gauge to come up with a possible construction.

The effect of natural rainfall variability in verification of rain modification experiments

Data from four concentrated rain gage networks in Illinois were used to investigate the effect of natural rainfall variability upon verification of cloud seeding experiments in midwestern, warm season rainfall on areas of county size or less. Hypothetical seeding experiments were made on network data for seasonal periods of 1 to 5 months and or durations of 1 to 10 years. Both target‐control and single‐area randomized experiments were investigated, and the data were grouped into air mass storms and all storms combined. Results indicated that the single‐area sampling experiments are influenced more by the effects of natural rainfall variability than the target control type, but that the background interference is substantial in both cases. The study clearly illustrates the pitfalls in judging the results of cloud seeding on short‐term experiments, and shows how verification may be affected by rain gage density and size of sampling area.

Experimental Study of Propeller-Induced Vibratory Pressures on Simple Surfaces and Correlation With Theoretical Predictions

Vibratory pressures exerted on cylindrical and flat-plate boundaries due to a model propeller were measured at three advance coefficients. A number of "free-space" measurements also were made. All measurements were made by driving a propeller past fixed pressure gages. This method yielded curves of pressure changes which are entirely free from background noise. The magnitudes of the free-space pressures were found to be larger than one half the corresponding magnitudes measured by gages mounted flush in a large plate at equal clearances from the propeller. By postulating that the finite area of the gage diaphragm produces a partial image of the propeller (and hence a larger pressure than that in free space) an experimental procedure was devised for correcting for this finite-area effect yielding results in good agreement with theory. A theoretical treatment of this effect of finite gage size is given in Appendix 2. The decay of maximum amplitudes of vibrating pressures is shown by means of three-dimensional plots. The pressures were found to become vanishingly small within approximately one propeller diameter fore and aft of the center of the propeller. The comparison with theoretically calculated pressures and forces gives very close agreement for free-space pressures and reasonable agreement for forces on a cylindrical surface. The agreement of both pressures and forces with theory is excellent for operation near the design advance ratio. A strong plea is made for further experiments with ship models in an effort to develop design criteria for practical application.