Design of a High-Q Diamond-Loaded Cavity for a Third-Harmonic Subterahertz Gyrotron Driven by a Low-Power Electron Beam

A continuous-wave (CW) high-harmonic gyrotron driven by a low-power electron beam is a compact radiation source demanded by terahertz applications. Its physical feasibility, however, is hampered by ohmic losses and mode competition in the gyrotron cavity. An ultralow-loss diamond loading of the cavity can give a clue to this problem. This article is concerned with theoretical aspects of mode selection and design for a gyrotron cavity loaded with coaxial rod made of chemical vapor deposition (CVD) diamond. As an example, the design of a high-Q diamond-loaded cavity for a third-harmonic 658-GHz gyrotron powered by a 0.1-A, 15-kV electron beam is presented. It is shown that the designed cavity enables the gyrotron to produce up to 116-W output power in a single oscillating mode

ASSESSING THE SUITABILITY OF GROUNDWATER FOR DRINKING AND AGRICULTURAL USES IN THE ZACHARO BASIN, SW PELOPONNESUS

Στην παρούσα εργασία εξετάζονται ο υδροχημικός χαρακτήρας των υπόγειων νερών της λεκάνης της Ζαχάρως και αξιολογείται η καταλληλότητα τους για υδρευτική και αρδευτική χρήση. Οι τρεις σημαντικότεροι υδροφόροι ορίζοντες της περιοχής είναι ο καρστικός της ζώνης Πίνδου, ο Νεογενής και ο αλλουβιακός. Ελήφθησαν 46 δείγματα νερού από πηγάδια, γεωτρήσεις και πηγές και αναλύθηκαν ως προς τις φυσικοχημικές παραμέτρους (pH, EC και TOC), τα κύρια στοιχεία (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, F-, SO4 2- and NO3-) και τα ιχνοστοιχεία (B, Fe, Mn, Cr, Pb, Se, Ni). Η καταλληλότητα των υπόγειων νερών για ύδρευση και άρδευση εξετάστηκε με τον υπολογισμό του Δείκτη Ποιότητας Νερού και των δεικτών SAR, %Na, RSC και KR. Το νερό του καρστικού και του αλλουβιακού υδροφόρου είναι «εξαιρετικής» ποιότητας για όλες τις χρήσεις. Αντίθετα, ο Νεογενής υδροφόρος παρουσιάζει σοβαρά προβλήματα υποβάθμισης της ποιότητας του νερού αφού το 20% των δειγμάτων είναι «πτωχής» και «εξαιρετικά πτωχής» ποιότητας ως προς την υδρευτική χρήση ενώ το 33% των δειγμάτων του αξιολογούνται ως «ακατάλληλα» για αρδευτική χρήση. Η υποβάθμιση της ποιότητας του νερού συνδέεται με φυσικές διεργασίες έντονης ιοντανταλλαγής, αφού η ικανότητα ανταλλαγής των υλικών του υδροφορέα είναι αυξημένη λόγω της παρουσίας αργιλικών ορυκτών και οργανικού υλικού.The hydrochemical character of the Zacharo basin groundwaters and their suitability for drinking and irrigation purposes are evaluated in this paper. The Pindos karst aquifer, the Neogene and the alluvial aquifer are the three most mportant aquifers of the study area. 46 water samples were taken from wells, boreholes and spring and they analyzed for the physicochemical parameters (pH, EC and TOC), major ions (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, F-, SO4 2- and NO3-) and trace metals (B, Fe, Mn, Cr, Pb, Se, Ni). The suitability of groundwaters for drinking and irrigation is evaluated by the calculation of Water Quality Index and the indices SAR, %Na, RSC and KR. The water of the karstic and alluvial aquifer is of “excellent” quality for both uses. On the other hand, the Neogene aquifer shows serious problems in respect with the degradation of water quality, since 20% of the samples are of “poor” and “extremely poor” quality for drinking purposes and 33% are “unsuitable” for irrigation. The degradation of water quality is attributed to natural processes of enhanced ion exchange, since the cation exchange capacity of the aquifer materials is increased due to the presence of clay minerals and organic matter

ASSESSING THE SUITABILITY OF GROUNDWATER FOR DRINKING AND AGRICULTURAL USES IN THE ZACHARO BASIN, SW PELOPONNESUS

Στην παρούσα εργασία εξετάζονται ο υδροχημικός χαρακτήρας των υπόγειων νερών της λεκάνης της Ζαχάρως και αξιολογείται η καταλληλότητα τους για υδρευτική και αρδευτική χρήση. Οι τρεις σημαντικότεροι υδροφόροι ορίζοντες της περιοχής είναι ο καρστικός της ζώνης Πίνδου, ο Νεογενής και ο αλλουβιακός. Ελήφθησαν 46 δείγματα νερού από πηγάδια, γεωτρήσεις και πηγές και αναλύθηκαν ως προς τις φυσικοχημικές παραμέτρους (pH, EC και TOC), τα κύρια στοιχεία (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, F-, SO4 2- and NO3-) και τα ιχνοστοιχεία (B, Fe, Mn, Cr, Pb, Se, Ni). Η καταλληλότητα των υπόγειων νερών για ύδρευση και άρδευση εξετάστηκε με τον υπολογισμό του Δείκτη Ποιότητας Νερού και των δεικτών SAR, %Na, RSC και KR. Το νερό του καρστικού και του αλλουβιακού υδροφόρου είναι «εξαιρετικής» ποιότητας για όλες τις χρήσεις. Αντίθετα, ο Νεογενής υδροφόρος παρουσιάζει σοβαρά προβλήματα υποβάθμισης της ποιότητας του νερού αφού το 20% των δειγμάτων είναι «πτωχής» και «εξαιρετικά πτωχής» ποιότητας ως προς την υδρευτική χρήση ενώ το 33% των δειγμάτων του αξιολογούνται ως «ακατάλληλα» για αρδευτική χρήση. Η υποβάθμιση της ποιότητας του νερού συνδέεται με φυσικές διεργασίες έντονης ιοντανταλλαγής, αφού η ικανότητα ανταλλαγής των υλικών του υδροφορέα είναι αυξημένη λόγω της παρουσίας αργιλικών ορυκτών και οργανικού υλικού.The hydrochemical character of the Zacharo basin groundwaters and their suitability for drinking and irrigation purposes are evaluated in this paper. The Pindos karst aquifer, the Neogene and the alluvial aquifer are the three most mportant aquifers of the study area. 46 water samples were taken from wells, boreholes and spring and they analyzed for the physicochemical parameters (pH, EC and TOC), major ions (Ca2+, Mg2+, Na+, K+, NH4+, HCO3-, Cl-, F-, SO4 2- and NO3-) and trace metals (B, Fe, Mn, Cr, Pb, Se, Ni). The suitability of groundwaters for drinking and irrigation is evaluated by the calculation of Water Quality Index and the indices SAR, %Na, RSC and KR. The water of the karstic and alluvial aquifer is of “excellent” quality for both uses. On the other hand, the Neogene aquifer shows serious problems in respect with the degradation of water quality, since 20% of the samples are of “poor” and “extremely poor” quality for drinking purposes and 33% are “unsuitable” for irrigation. The degradation of water quality is attributed to natural processes of enhanced ion exchange, since the cation exchange capacity of the aquifer materials is increased due to the presence of clay minerals and organic matter

Dermoscopic evaluation of amelanotic and hypomelanotic melanoma

Objective: To determine the predictive dermoscopic features of amelanotic and hypomelanotic melanoma

Design of MW-Class Coaxial Gyrotron Cavities With Mode-Converting Corrugation Operating at the Second Cyclotron Harmonic

This article presents investigations on the design of coaxial gyrotron cavities with mode-converting corrugations, operating at the second harmonic of the electron cyclotron frequency with output power of the order of megawatts. The suppression of the competing modes interacting at the fundamental cyclotron frequency is achieved by the combination of a corrugated coaxial insert and mode-converting corrugation on the outer wall. The outer corrugation couples the key competing modes to lower order modes with reduced quality factor. The design steps, which form a generally applicable design procedure, are described in detail. As an illustrative example, the proposed procedure is used for the design of a cavity for a fusion-relevant, second-harmonic MW-class gyrotron, operating at 170 GHz with the TE 37,1837,18 mode. From the simulations, it is found that for the proposed design, this mode is excited with an output power of around/ ∼ 1.5 MW. Two additional paths for cavity optimization toward even higher output power are also presented

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

High-Frequency MW-class Coaxial Gyrotron Cavities Operating at the Second Cyclotron Harmonic

Second-harmonic operation of gyrotron oscillators offers the possibility to generate millimeter and submillimeter radiation at half the value of the magnetic field required for operation at the fundamental cyclotron frequency (first harmonic). However, being inherently weaker than the interaction at the first harmonic, high-power second-harmonic continuous-wave (CW) operation employing high-order modes faces strong mode competition from the first-harmonic competing modes. It is shown that coaxial cavities with a corrugated insert allow to drastically enhance the mode selectivity at the second harmonic and suppress the first-harmonic competitors in MW-class gyrotrons. Detailed design considerations for coaxial cavities are presented and specific cavity designs for various candidate operating modes are given. We demonstrate numerically, with multimode interaction simulations, stable second-harmonic CW generation of 2 MW output power at 170 GHz and 0.7 MW at 280 GHz, using high-order modes with eigenvalues > 100. The presented results show the possibility to design second-harmonic gyrotrons with cost-effective magnet systems and achieve MW-class CW operation at frequencies above 250 GHz

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

The existing ECRH system at W7-X consists of 10 gyrotrons, with output power levels ranging from 0.6 MW up to 1.0 MW each at a frequency of 140 GHz, quasi-optical transmission lines and microwave launchers at the plasma vessel. Compared to other large fusion experiments, W7-X has a relatively low power-to-volume ratio. However high heating power is particularly necessary for achieving high plasma beta values, where the improved confinement of fast ions, one of the optimization criteria of W7-X, can be examined. It is therefore necessary to expand the ECRH systems in several consecutive steps. It is planned to increase the number of gyrotron positions from 10 to 12 and at the same time to evolve the gyrotron output power in several development steps from 1 MW to nominal 1.5 MW and, finally, up to 2 MW. At the same time, the transmission lines will also be upgraded for 2 MW operation. A special effort is also made to improve the reliability of the system by the fast control system