GEOMETRY FACTORS IN CORROSION FATIGUE CRACK PROPAGATION

Abstract— Fatigue crack growth rates for a steel in saltwater at different but constant stress intensity factor ranges have been evaluated as a function of the crack length (as measured from the notch root) for cracks longer than so-called "short" cracks. Equations describing the crack growth rate as a function of both the crack length and the stress intensity factor range have been obtained, and the effect of simulated infinite thickness of the specimens is discussed. The equations satisfactorily describe the numerous literature data for different steels, different specimens and different test conditions.     

Diagnostics design for steady-state operation of the Wendelstein 7-X stellarator

The status of the diagnostic developments for the quasistationary operable stellarator Wendelstein 7-X (maximum pulse length of 30 min at 10 MW ECRH heating at 140 GHz) will be reported on. Significant emphasis is being given to the issue of ECRH stray radiation shielding of in-vessel diagnostic components, which will be critical at high density operation requiring O2 and OXB heating.     

A scintigraphic method of examining the patency of oviducts using 133Xe

Described below is the radioisotope method of examining the patency of oviducts using a solution of 133Xe. Scintigraphic pictures of the uterine cavity and oviducts were obtained with a Jumbo Toshiba gamma-camera; they were subsequently analysed by an Informatek SIMIS-3 data processing system. A total of 30 women aged between 20 and 36 with primary or secondary infertility were examined. The patency of oviducts and the shape of the uterine cavity was assessed on the basis of: the overall picture of the activity of 133Xe in the uterine cavity and oviducts, the isocontours of the overall picture, curves of increasing and decreasing activity in the fallopian tubes, and the spatial picture of activity distribution in the uterus and fallopian tubes. The results of the examinations corresponded in all cases with the diagnosis made on the basis of hysterosalpingography. An advantage of the isotope method of examining the patency of fallopian tubes and the shape of the uterine cavity is the fact that it is an examination of a dynamic nature, completely safe for the patient and exposes the patients to a considerably lower dose of irradiation than during hysterosalpingography.     

Simple formulas for analysis of C-V characteristics of MIS capacitor

Paper presents few simple formulas which permit for a quick determination of the parameters of MIS capacitor on the grounds of the high-frequency C-V characteristics of MOS capacitor. These formulas allow for a simple and quick interpretation of the experimental data and can be used in the design of VLSI circuits as well as to the automatization of measurement on a technological line. The error of the proposed formulas was analyzed in the range U_F = 9–16.     

Magnetic resonance imaging differentiation of adrenal masses at 1.5 t: t2-weighted images,chemical shift imaging,and gd-dtpa dynamic studies

The purpose of our study was to assess the potential role of spin-echo (SE), chemical shift, and gadolinium-enhanced magnetic resonance imaging (MRI) in the differentiation of adrenal masses.Seventy-two adrenal masses (26 nonhyperfunctioning adenomas, 16 aldosterone-secreting adenomas and 6 other different benign cortical masses, 18 pheochromocytomas, and 6 malignant masses) in 63 patients were evaluated with spin-echo sequences, chemical shift imaging (CSI) and gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA) dynamic studies. Ratios and indices of signal intensity for all examined MRI methods were calculated and examined for significance of difference between different types of adrenal masses.Quantitative magnetic resonance evaluation of adrenal masses showed significant differences (at least<0.01) between nonhyperfunctioning adenomasvs. pheochromocytomas orvs. malignant lesions orvs. aldosterone-secreting adenomas and between pheochromocytomasvs. malignant lesions. The most specific indicators of adrenal mass character proved to be the CSI ratio based on opposed-phase and in-phase two-dimensional fast low-angle shot (FLASH) images, reflecting lipid content in the lesion, and Gd-DTPA dynamic studies ratios reflecting contrast agent inflow and washout in the lesion: Wo_max/last and Dyn_1.2–3.2. There was no overlap of CSI ratio between adenomas and pheochromocytomas. The overlap of ranges of CSI ratio between nonhyperfunctioning adenomas and aldosterone-secreting adenomas was only 18.5%. There was no overlap of Wo_max/last ratio between adenomas and pheochromocytomas, or adenomas and malignant lesions. The overlap of ranges of Dyn_{1.2– 3.2} ratio between pheochromocytomas and malignant lesions was only 17.6%.MRI enables good visualization and specific characterization of adrenal masses. The optimal MRI protocol for the adrenal region is presented.Address for correspondence: Imaging Department, Warsatv Province Hospital, ul. Kondratowicza 8, 03-285 Warsaw, Poland.     

The Application of Mixture Distribution for the Estimation of Extreme Floods in Controlled Catchment Basins

In the estimation of distribution of annual maximum flows it is a generally accepted assumption that the sequence of observations originates from a homogeneous population. This assumption, however, is rarely met. The observed annual maximum flow are only in part generated by flood events. The remaining ones are the result of the effect of other hydrological processes that do not have that character. For this reason, a new solution to this problem is proposed in the paper. It is assumed that the sought distribution is a mixture of two probability distributions: a three-parameter GEV distribution, describing flows generated by events with flood character, and a two-parameter gamma distribution, accounting for maximum annual flows that do not have such a character. The paper presents both the method of estimation of the mixture distribution and its application for gauging stations selected so as to take into account possible the most diverse conditions of meteorological, hydrological and geomorphological character. The area with such a high diversification, selected for the study, is the catchment basin of upper and central river Odra (South-West Poland). In the studied water gauge profiles the proposed mixture distribution indicates correct fit. Its advantages and limitations are presented through a comparative analysis with results obtained during estimation of distributions of maximum annual flows by means of standard methods.     

Einige Betrachtungen über die kapazitive Hochspannungsmessung und deren Fehler

Zusammenfassung Die Gleichrichtermethode wird prinzipiell zur Messung der Maximalwerte der Spannungskurven, die blo\ zwei Scheitelwerte in einer Periode aufweisen, angewendet. Die Spannungskurven, die dieser Bedingung nicht entsprechen, kommen aber in der Praxis manchmal vor. In diesem Falle wird die Messung der Scheitelspannung mit einem Fehler belastet. Eine praktische Methode der Bestimmung dieses Fehlers existiert unseres Wissens noch nicht.Die anderen hier vorkommenden Fehler, die ihre Ursache in der Unvollkommenheit der Anordnung der Elemente haben, können nach dem Verfahren von H. König bestimmt werden, das jedoch keinen allgemeinen Charakter hat und ziemlich umstÄndlich ist. Es ist besser die obere Grenze des dabei begangenen Fehlers auf die hier nÄher beschriebene einfache Weise zu bestimmen.Au\erdem kann die Messung mit anderen Fehlern belastet werden, deren Ursache in der mangelhaften Ausführung der Me\anordnung liegt (schlechte Kontakte, Sprühen der Zuleitung usw.). Solche Fehlerquellen sollen sorgfÄltig geprüft und beseitigt werden.Bei der kapazitiven Spannungsmessung empfiehlt es sich, die dunkelglühenden Elektronenröhren als Gleichrichter zu verwenden. Man kann dann eine Zusatzbatterie vermeiden, die sonst zur Trennung der Arbeit der Gleichrichter nötig ist.Unter diesen Bedingungen kann die Gleichrichtermethode der Messung der Scheitelwerte der Hochspannung als eine sehr praktische und genaue Me\methode, auch in Fabriklaboratorien, betrachtet werden.Die obige Arbeit wurde im Hochspannungslaboratorium der Technischen Hochschule Warschau im Jahre 1931 ausgeführt.     

A new approach to the estimation of basic flow parameters within the electromagnetic measuring method for open channels

This column describes two issues for electromagnetic flowmeters used in open channels: 1) practical aspects of signal conditioning and 2) a new concept of signal processing to be applied in this field. The new signal processing technique uses a least squares (LS) method and provides information about the fluid's flow rate and its level in open channels. We confirmed these concerns by experiments carried out with a laboratory model of the electromagnetic flowmeter.