Exactness Of Measurement Research Articles

Cartographies of Genocide

Cartographies of Genocide

Simultaneous measurement of the velocity of an ultrasonic shear wave and the thickness of a test object with plane-parallel boundaries using two antenna arrays

Methods for the determination of the unknown velocity of the propagation of shear US waves and the unknown thickness of a test object were considered. Two antenna arrays working in the double-scanning mode, where echo signals are recorded, which were emitted and received by all pairs of antenna-array elements, were suggested. Antenna arrays on prisms were mounted on the test-object surface towards each other. An algorithm for the treatment of measured echo signals was designed using a method that is similar to the least-squares method. The use of the algorithm enables one to simultaneously determine the sound velocity and thickness of a test object with plane-parallel boundaries with an exactness greater than 0.5%. In this article, the factors were studied that affect the exactness of measurements and methods of their elimination or minimization. The results of numerical experiments and the use of the method on three samples relative to measurements using an IN-5101A instrument are given.

Increase in the exactness of measurement of physical parameters of high-temperature superconductor materials

A procedure for estimating the critical temperature Tc and width ΔTc for the superconducting transition of high-temperature superconductor materials based on plotting the first derivative of the temperature correlation dependence of the electrical resistance of a sample is developed. The critical point of the derivative corresponds to Tc, and its width at half-height corresponds to ΔTc. The procedure provides a decrease in the relative error of estimation of Tc and ΔTc for qualitative samples by a factor of 1.7–2.

A Protocol for Cranial Base Reference in Cephalometric Studies

Establishment of the cranial base references and the coordinate system is important for measurement of events occurring on the face. The literature suggests that the horizontal axis is obtained by tracing a line in clockwise direction at seven degrees from the Sella-Nasion line, and the vertical axis is perpendicular to this former axis passing through the Sella point. However, could this standardization better represent the angle between the Sella-Nasion line and Frankfort Horizontal Plane in a Brazilian population and be employed in cephalometric studies? Thus, the present study had two purposes: to identify the cranial base inclination in adult patients presenting with intermaxillary anteroposterior skeletal disharmony and to evaluate the reliability of a protocol to reproduce the cranial base reference. Lateral cephalograms of three different times were traced: T0) onset of orthodontic treatment and immediately before the orthognathic surgery, T1) six months after surgery, and T2) one year after surgery. The results displayed a mean cranial base inclination of 7.91 degrees. Variation of the intraindividual data allowed the conclusion that the protocol proposed by utilization of an individual template of the cranial base reference was effective for the exactness of measurements in cephalometric studies.

The control of body position in the stick insect (Carausius morosus), when walking over uneven surfaces

An investigation has been made of the way, in which the height of the body of an insect (Carausius morosus) is controlled when walking over an uneven terrain. The animals have been filmed from the side while walking over different types of irregularity (step up, step down, obstacle, ditch). A frame by frame analysis of the height of the three thoracic segments of the insect has been performed. A computer model has been set up, which is able to describe the experimental results within the exactness of measurement. This model consists of three independent height controllers, each having a unique characteristic. The coupling of these three controllers is performed mechanically. One possible interpretation of this model is that the height of each segment is controlled by a closed loop mechanism with a proportional element as a controller.