Willis couplings in continuously varying cross-sectional area duct.

Acoustic wave propagation in a one-dimensional periodic and asymmetric duct is studied theoretically and numerically to derive the effective properties. Closed form expressions for these effective properties, including the asymmetric Willis coupling, are derived through truncation of the Peano-Baker series expansion of the matricant (which links the state vectors at the two sides of the unit-cell) and Padé's approximation of the matrix exponential. The results of the first-order and second-order homogenization (with Willis coupling) procedures are compared with the numerical results. The second-order homogenization procedure provides scattering coefficients that are valid over a much larger frequency range than the usual first-order procedure. The frequency well below which the effective description is valid is compared with the lower bound of the first Bragg bandgap when the profile is approximated by a two-step function of identical indicator function, i.e., two different cross-sectional areas over the same length. This validity limit is then questioned, particularly with a focus on impedance modeling. This article attempts to facilitate the engineering use of Willis materials.

Surface Love-type waves propagating through viscoelastic functionally graded media.

This paper deals with the solution of the model equations, which describes the propagation of the surface Love-type waves in a waveguide structure consisting of a lossy isotropic inhomogeneous layer placed on a viscoelastic homogeneous substrate. The paper points to the possibility of using the triconfluent Heun differential equation to solve the model equation. The exact analytical solution within the inhomogeneous layer is expressed by the triconfluent Heun functions. The exact solutions are general in the sense that only the internal parameters of the triconfluent Heun functions can change the spatial dependencies of the material parameters in the inhomogeneous layer's thickness direction. Based on the comparison, the limits of the WKB method applicability are discussed. It is further demonstrated that substrate losses affect the dispersion characteristics only to a small extent. Using examples in which the surface layer is represented by functionally graded materials, it was shown that the distance between the modes can be influenced through those materials.

Estimating the upper limit of prehistoric peak ground acceleration using an in situ, intact and vulnerable stalagmite from Plavecká priepast cave (Detrekoi-zsomboly), Little Carpathians, Slovakia-first results.

Earthquakes hit urban centres in Europe infrequently, but occasionally with disastrous effects. Obtaining an unbiased view of seismic hazard (and risk) is therefore very important. In principle, the best way to test probabilistic seismic hazard assessments (PSHAs) is to compare them with observations that are entirely independent of the procedure used to produce PSHA models. Arguably, the most valuable information in this context should be information on long-term hazard, namely maximum intensities (or magnitudes) occurring over time intervals that are at least as long as a seismic cycle. The new observations can provide information of maximum intensity (or magnitude) for long timescale as an input data for PSHA studies as well. Long-term information can be gained from intact stalagmites in natural caves. These formations survived all earthquakes that have occurred over thousands of years, depending on the age of the stalagmite. Their 'survival' requires that the horizontal ground acceleration (HGA) has never exceeded a certain critical value within that time period. Here, we present such a stalagmite-based case study from the Little Carpathians of Slovakia. A specially shaped, intact and vulnerable stalagmite in the Plavecká priepast cave was examined in 2013. This stalagmite is suitable for estimating the upper limit of horizontal peak ground acceleration generated by prehistoric earthquakes. The critical HGA values as a function of time going back into the past determined from the stalagmite that we investigated are presented. For example, at the time of Jóko event (1906), the critical HGA value cannot have been higher than 1 and 1.3 m/s2 at the time of the assumed Carnuntum event (∼340 AD), and 3000 years ago, it must have been lower than 1.7 m/s2. We claimed that the effect of Jóko earthquake (1906) on the location of the Plavecká priepast cave is consistent with the critical HGA value provided by the stalagmite we investigated. The approach used in this study yields significant new constraints on the seismic hazard, as tectonic structures close to Plavecká priepast cave did not generate strong earthquakes in the last few thousand years. The results of this study are highly relevant given that the two capitals, Vienna and Bratislava, are located within 40 and 70 km of the cave, respectively.

Effect of intraperitoneal administration of oxygen on the course of experimentally induced peritonitis.

Over the first 3 days of experimentally induced peritonitis, 40 rabbits were given oxygen intraperitoneally (IP) up to a pressure of 3 to 5 mm Hg in the peritoneal cavity at 12-hour intervals. Compared with a control group, significant differences were recorded in the mortality rate within the studied 7-day period of peritonitis (p less than 0.05). In 29 rabbits with intraperitoneal administration of oxygen, the size of the area that formed the inner wall of the abscess cavity was significantly smaller (p less than 0.01) on day 7 of peritonitis than in the control group. The number of samples obtained from the abscesses positive for Clostridium perfringens (p less than 0.05) and for Staphylococcus aureus (p less than 0.001) was significantly lower in rabbits that had received intraperitoneal oxygen than in the control group. The number of samples from the abscesses positive for Escherichia coli and Streptococcus faecalis was significantly lower in the control group than in the group with intraperitoneal administration of oxygen (p less than 0.05). These results indicate that intraperitoneal administration of oxygen has an effect on the mortality rate associated with peritonitis, the size of the intraperitoneal abscess, and the bacterial composition of these abscesses.

[Anomalous myocardial vascularization. Case report]. / Prípad anomální vaskularizace myokardu. Kasuistika.

A 52 years old woman was surgically treated at her 27 years of age for a defect of atrium septum of IInd type. The defect was covered by a patch taken from pericardium. The operation was followed twice by lung embolism. In 1986 there occurred deterioration of the condition. A recanalization of the defect was detected and the patient was recommended to operation. The operation was preceded by selective coronarography, which proved anomalous vascularization of myocardium in the left atrium. Echocardiography and computer tomography detected a pathological formation in this area. The suggested formation was not found during the operation. The explanation of anomalous vascularization of myocardium is believed to have been caused by a thrombus after the first operation; the thrombus may have caused proliferation of coronary vessels, then paradoxically resulted in lung embolism and the pathological vascularization persisted.

[Postoperative aneurysm of the right ventricle]. / Pooperacní aneuryzma pravé komory.

After reconstruction of the right ventricular outflow tract in the tetralogy of Fallot by means of a pericardial patch or patch from synthetic material in rare instances an aneurysm of the right ventricle may develop. The authors diagnosed seven postoperative aneurysms of the right ventricle in a group of 220 children operated on account of the tetralogy of Fallot (3.18%), incl. four where an urgent surgical operation was necessary. The aneurysm developed once after suture of the transmural pericardial patch and six times after an enlarging plastic operation of the outflow tract of the right ventricle by means of a synthetic patch. Of the four operated patients three times a pseudoaneurysm was involved and once a true aneurysm.

[Type II atrial septal defects in adulthood]. / Defekty sínového septa II. typu v dospelosti.

Indication criteria of adult patients with atrial septal defects type II for surgery are not uniform so far. In a group of 150 adult patients with atrial septal defects type II operated in 1978-1987 at the cardiosurgical department in Brno the authors report the following results: a mortality on operation of 0.7% and a very satisfactory postoperative condition in almost all patients. In a group of 16 patients examined in 1978-1987 but not operated because of a defect of the atrial septum type II of minor haemodynamic impact the authors observed after long-term follow up a deterioration of the health status in four patients and they express therefore doubts on the rigorous criterium for operation a 1.5:1 left-to-right shunt in adult patients and assume that in some instances the defect is indicated for surgery even when the shunt is small.

[Long-term results of radical operations on the ventricular septum with organic pulmonary hypertension]. / Dlouhodobé výsledky radikální operace komorového septa s organickou plicní hypertenzí.

From a total group of 189 children with a ventricular septal defect operated in 1978-1985 at the Cardiosurgical and Transplantation Department in Brno the authors followed up 60 patients with pulmonary hypertension. In addition to catheterization and echocardiographic examination, they made in 28 patients (46%) a preoperative pulmonary biopsy. In the majority of children before and after operation by catheterization the pulmonary tension Rp/Rs was measured and in some also pulmonary vascular resistance. During the echocardiographic examination attention was focused on the possibility to as the pulmonary tension by pulsed Doppler and continuous technique, on the detection of left-to-right shunt, pulmonary or tricuspid insufficiency. Of 60 patients 5 children (8.3%) died soon after operation, one patient died six years after operation. Long-term postoperative follow up made is possible to define more accurate indication criteria for operation as well as for pulmonary biopsy.

Surgical treatment of atrial septal defects.

An analysis is presented of the results attained in 207 patients operated for isolated atrial septal defect at Centre of Cardiac Surgery in Brno from Jan. 1, 1978 to March 31, 1982. The paper discusses classification of the defects, the surgical procedure, results and complications, as well as indications and counterindications for surgery. Early mortality was zero. Emphasis is placed on the need to operate as soon as possible after detection of a haemodynamically significant shunt, i.e. before developing pulmonary hypertension.