Damage-based fracture with electro-magnetic coupling

Acoupled elastic and electro-magnetic analysis is proposed including finite displacements and damage-based fracture. Piezo-electric terms are considered and resulting partial differential equations include a non-classical wave equation due to the specific constitutive law. The resulting wave equation is constrained and, in contrast with the traditional solutions of the decoupled classical electromagnetic wave equations, the constraint is directly included in the analysis. The absence of free current density allows the expression of the magnetic field rate as a function of the electric field and therefore, under specific circumstances, removal of the corresponding magnetic degrees-offreedom. A Lagrange multiplier field is introduced to exactly enforce the divergence constraint, forming a three-field variational formulation (required to include thewave constraint). No vector-potential is required or mentioned, eliminating the need for gauges. The classical boundary conditions of electromagnetism are specialized and a boundary condition involving the electric field is obtained. The spatial discretization makes use of mixed bubble-based (of the MINI type) finite elementswith displacement, electric field and Lagrange multiplier degrees-of-freedom. Three verification examples are presented with very good qualitative conclusions and mesh-independence

Electric properties of granitic rocks

The objective of this work is to clarify the role of water content on the charge trans- port mechanisms of different granitic rocks. The mineralogical content of the rocks will also be taken into account. From the electrical point of view these materials are rather insulating porous media where charge injection creates different phenomena like build-up charges, space charge limited currents, surface effects and other behav- iors that resemble much a variety of oxides, like AlO

Influence of seismic activity on the atmospheric electric field in Lisbon (Portugal) from 1955 to 1991

In the present study, we considered the influence of seismic activity on the atmospheric electric field recorded at Portela meteorological station (Lisbon, Portugal) for the period from 1955 to 1991. To this end, an exploratory method was developed, which involved the selection of events for which the distance from the atmospheric electrical field sensor to the earthquake epicenter is smaller than the preparation radius of the event. This enabled the correlation of the atmospheric electric field variations with a quantity S, defined basically as the ratio of the earthquake preparation radius to the distance between the sensor and the event epicenter. The first results show promising perspectives, but clearly a more profound study is required, in which a careful analysis of the weather conditions and other variables, like atmospheric radon levels, must be considered

SEISMO-ELECTROMAGNETIC PHENOMENA IN TECTONICALLY ACTIVE REGIONS

This work presents a research plan that aims to monitor seismo-electromagnetic signals in seismic active regions. Two effects will be considered: electromagnetic field emissions and radio broadcastings. Our study will be focused in the analysis of low magnitude earthquakes almost completely disregarded in literature. We aim to collect novel seismo-electromagnetic emission data emerging from seismic activity. We expect to address the time variation of electromagnetic properties of the crust in relation with the strain field and complement it with the development of proper models. Experimental studies based on the electrical properties of rocks will also be done aiming the understanding of pressure stimulated currents and voltages that produce detectable electromagnetic radiation and can be a cause for seismo-electromagnetic signals

Agrobacterium tumefaciens-mediated transformation revealed an alkaline phytoceramidase that is required in pathogenicity of Colletotrichum kahawae to Coffea arabica

info:eu-repo/semantics/publishedVersio

Объем остаточной тиреоидной ткани и эффективность постоперационной радиойодтерапии больных с дифференцированными формами рака щитовидной железы

Резюме. У 210 больных с дифференцированными формами рака щитовидной железы изучено влияние массы участков остаточной ткани щитовидной железы (ОТЩЖ) на эффективность радиойодтерапии (РЙТ). Через 4–6 нед после хирургического лечения выполняли диагностическую сцинтиграфию с 70–80 МБк 131I, по данным которой на основании эллипсоидной модели рассчитывали объем ОТЩЖ. РЙТ проводили активностями 1,9–4,7 ГБк, контрольную сцинтиграфию выполняли через 4–6 мес. Эффективность первого курса РЙТ при объеме ОТЩЖ 1 см3 и менее составляла 88,9%, при объеме более 4 см3 — 69,3% (р < 0,05). Установлена достоверная корреляция между объемом ОТЩЖ и эффективностью первого курса РЙТ. При наличии нескольких участков ОТЩЖ эффективность РЙТ определяется не столько их количеством и суммарным объемом, сколько объемом каждого участка. Ключевые слова: дифференцированный рак щитовидной железы, тиреоидэктомия, радиойодтерапия, остаточная ткань щитовидной железы.Summary. The influence of the mass of the residual thyroid tissue (RTT) on the efficacy of radioiodine therapy (RT) was investigated in 210 patients with differentiated forms of thyroid cancer (DFTC). 4 to 6 weeks after surgery, diagnostic 131J scintigraphy (70–80 MBq) was applied. On the basis of data obtained, the RTT size was measured based on an ellipsoidal model. Activities applied in RT ranged between 1,9–4,7 GBq; control scintigraphy was performed in 4 to 6 months. The efficacy of the first RT course was 88,9% in patients with RTT of 1 cm3 or smaller and 69,3% in patients with RTT of 4 cm3 or larger (р<0,05). A significant correlation was found between the size of RTT and the efficacy of the first RT course. In cases where there were several RTT areas, the RT efficacy depended on the overall size of each area rather than on the number of such areas. Key Words: differentiated thyroid cancer, thyreoidectomy, radioiodine therapy, residual thyroid tissue

Anomalies Observed in VLF and LF Radio Signals on the Occasion of the Western Turkey Earthquake (Mw = 5.7) on May 19, 2011

VLF radio signals lie in the 10 - 60 kHz frequency band. These radio signals are used for worldwide navigation support, time signals and for military purposes. They are propagated in the earth-ionosphere wave-guide mode along great circle propagation paths. So, their propaga-tion is strongly affected by the ionosphere conditions. LF signals lie in 150 - 300 kHz frequency band. They are used for long way broadcasting by the few (this type of broadcasting is going into disuse) transmitters located in the world. These radio signals are characterized by the ground wave and the sky wave propagation modes [1]. The first generates a stable signal that propagates in the channel Earth-troposphere and is affected by the surface ground and troposphere condition. The second instead gives rise to a signal which varies greatly between day and night, and between summer and winter, and which propagates using the lower ionosphere as a reflector; its propagation is mainly affected by the ionosphere condi-tion, particularly in the zone located in the middle of the transmitter-receiver path. The propagation of the VLF/LF radio signals is affected by different factors such as the meteorological condition, the solar bursts and the geo-magnetic activity. At the same time, variations of some parameters in the ground, in the atmosphere and in the ionosphere occurring during the preparatory phase of earthquakes can produce disturbances in the above men-tioned signals. As already reported by many previous studies [2-18] the disturbances are classified as anoma-lies and different methods of analysis as the residual dA/ dP [15], the terminator time TT [9], the Wavelet spectra and the Principal Component Analysis have been used [6,7]. Here the analysis carried out on LF and VLF radio signals using three different methods on the occasion of a strong earthquake occurred recently in Turkey is pre-sented

Thermodynamic Consistency of the qq-Deformed Fermi-Dirac Distribution in Nonextensive Thermostatics

The $q$-deformed statistics for fermions arising within the non-extensive thermostatistical formalism has been applied to the study of various quantum many-body systems recently. The aim of the present note is to point out some subtle difficulties presented by this approach in connection with the problem of thermodynamic consistency. Different possible ways to apply the $q$-deformed quantum distributions in a thermodynamically consistent way are considered.Comment: 4 pages, 1 figur

Wavelet analysis of the LF radio signals collected by the European VLF/LF network from July 2009 to April 2011

In 2008, a radio receiver that works in very low frequency (VLF; 20-60 kHz) and LF (150-300 kHz) bands was developed by an Italian factory. The receiver can monitor 10 frequencies distributed in these bands, with the measurement for each of them of the electric field intensity. Since 2009, to date, six of these radio receivers have been installed throughout Europe to establish a ‘European VLF/LF Network’. At present, two of these are into operation in Italy, and the remaining four are located in Greece, Turkey, Portugal and Romania. For the present study, the LF radio data collected over about two years were analysed. At first, the day-time data and the night-time data were separated for each radio signal. Taking into account that the LF signals are characterized by ground-wave and sky-wave propagation modes, the day-time data are related to the ground wave and the night-time data to the sky wave. In this framework, the effects of solar activity and storm activity were defined in the different trends. Then, the earthquakes with M ≥5.0 that occurred over the same period were selected, as those located in a 300-km radius around each receiver/transmitter and within the 5th Fresnel zone related to each transmitter-receiver path. Where possible, the wavelet analysis was applied on the time series of the radio signal intensity, and some anomalies related to previous earthquakes were revealed. Except for some doubt in one case, success appears to have been obtained in all of the cases related to the 300 km circles in for the ground waves and the sky waves. For the Fresnel cases, success in two cases and one failure were seen in analysing the sky waves. The failure occurred in August/September, and might be related to the disturbed conditions of the ionosphere in summer

Control of the diffusible hydrogen content in different steel phases through the targeted use of different welding consumables in underwater wet welding

Due to the rising number of offshore structures all over the world, underwater wet welding has become increasingly relevant, mainly as a repair method. Welding in direct contact with water involves numerous challenges. A topic focused by many studies is the risk of hydrogen-induced cracking in wet weldments due to hardness values of up to 500 HV 0.2 in the heat-affected zone (HAZ) and high levels of diffusible hydrogen in the weld metal. The risk of cracking increases as the equivalent carbon content rises, because the potential to form martensitic structures within the HAZ rises too. Thus, high-strength steels are especially prone to hydrogen-induced cracking and are considered unsafe for underwater wet repair weldments. © 2020 The Authors. Materials and Corrosion published by Wiley-VCH Gmb