The influence of Si and V on the kinetics of phase transformation and microstructure of rapidly solidified Al-Fe-Zr alloys

The influence of Si and V on the precipitation kinetics of the rapidly solidified (RS) Al-Fe-Zr alloys is presented. Precipitation kinetics and microstructural development of RS Al-Fe-Zr alloys with Si or V addition have been investigated by the combination of four point electrical resistance measurement, optical microscopy, transmition electron microscopy (TEM) and scanning electron microscopy (SEM). For verification of the electrical resistivity measurement results differential scanning calorimetry (DSC) and differential thermal analysis (DTA) was also applied. Rapidly solidified samples, in the form of thin ribbons, were prepared with the single roll melt spun technique. For determination of the distinctive temperatures at which microstructural transformations occur in-situ electrical resistivity measurement during heating of the ribbons with various constant heating rates has been used. It was found that microstructure decomposition depends on heating rate and shifts to higher temperatures with increasing heating rate. After heating above the distinctive transition temperatures, heating was stopped and microstructure of the samples examined by electron microscopy

Feasibility studies of a Level-1 Tracking Trigger for ATLAS

The existing ATLAS Level-1 trigger system is seriously challenged at the SLHC's higher luminosity. A hardware tracking trigger might be needed, but requires a detailed understanding of the detector. Simulation of high pile-up events, with various data-reduction techniques applied will be described. Two scenarios are envisaged: (a) regional readout - calorimeter and muon triggers are used to identify portions of the tracker; and (b) track-stub finding using special trigger layers. A proposed hardware system, including data reduction on the front-end ASICs, readout within a super-module and integrating regional triggering into all levels of the readout system, will be discussed

Fracture of drilling head pipe connection due to quenching of heat affected zone (HAZ)

The drilling head pipe connection is made of quenched and tempered steel 34CrNiMo6. The steel characteristic is high hardenability. Due to unsuitable and untested welding technology the heat affected zone (HAZ) cooling rate after welding surpassed the upper critical cooling rate. During horizontal drilling of the rock, the resulting brittle martensite could not bear the dynamic loads which led to a brittle fracture of the pipe connection

Distorzija dijelova prstena tijekom preciznog utiskivanja

Distortion control is one of the most important concerns of the metal processing industry, which also includes the fine-blanking technology. Fine-blanking of sheet metal involves metal flow and shearing, which result in complex deformation. Distortion occurs during the removal of parts from the tool due to the relaxation of internal stresses. Internal stresses that are generated during fine-blanking have an important effect on the shape and size of parts after fine-blanking. The distortion of ring type products during fine-blanking was analyzed by using dimension measurements, microscopic observation and numerical simulation.Kontrola distorzije je jedan od najvažnijih poslova u metaloprerađivačkoj industriji, što također vrijedi i za tehnologiju preciznog utiskivanja. Precizno utiskivanje trake uključuje tok i rezanje materijala, što se odražava na složenost deformacije. Distorzija nastaje tijekom uklanjanja dijelova iz alata zbog oslobađanja unutarnjih naprezanja. Promjena oblika tijekom preciznog utiskivanja prstenova analizirana je mjerenjima dimenzija, mikroskopskim zapažanjima i numeričkim simulacijama

Tests of a proximity focusing RICH with aerogel as radiator

Using aerogel as radiator and multianode PMTs for photon detection, a proximity focusing Cherenkov ring imaging detector has been constructed and tested in the KEK $\pi$2 beam. The aim is to experimentally study the basic parameters such as resolution of the single photon Cherenkov angle and number of detected photons per ring. The resolution obtained is well approximated by estimates of contributions from pixel size and emission point uncertainty. The number of detected photons per Cherenkov ring is in good agreement with estimates based on aerogel and detector characteristics. The values obtained turn out to be rather low, mainly due to Rayleigh scattering and to the relatively large dead space between the photocathodes. A light collection system or a higher fraction of the photomultiplier active area, together with better quality aerogels are expected to improve the situation. The reduction of Cherenkov yield, for charged particle impact in the vicinity of the aerogel tile side wall, has also been measured.Comment: 4 pages, 8 figure

TREATMENT WITH TAMSULOSIN IN PATIENTS WITH DISTAL URETERAL CALCULI

Background: Symptomatic ureteral calculi are one of the most important issues in urologist emergency clinical settings. Spontaneous passage of distal ureteral calculi is usually achieved with good hydration and spasmoanalgetic drugs. alpha-blocker therapy may facilitate and accelerate the spontaneous passage of ureteral stones.Patients and methodsIn retrospective study we analyzed patients with renal colic admitted to our department in 2006. All of them had clinical examination, urine and blood analysis, plain radiography (number, size and location of radiopaque calculi) and intravenous pyelography (kidney function and morphology). All patients with distal ureteral calcus were treated with spasmoanalgetics and with or without alpha-adrenergic antagonist tamsulosin. We analyzed eventual spontaneous passage of the calculi, additional procedures (splints, ureterorenoscopy, open procedures, extracorporeal shock wave lithotripsy (ESWL)). We used Student's t-test for statistical analysis.Results48 from 72 patients had urinary calculus. 35 (73 %) of them had calculus in the distal part of ureter. 17 (49 %) of 35 patients with distal ureteral calculus were treated with tamsulosin and in all (100 %) spontaneous stone passage was observed. 18 (51 %) patients were not treated with tamsulosin and spontaneous passage was observed in 18 (65 %) patients (p = 0.000).ConclusionsTamsulosin therapy promotes expulsion of ureteral stones

Sequent Calculus in the Topos of Trees

Nakano's "later" modality, inspired by G\"{o}del-L\"{o}b provability logic, has been applied in type systems and program logics to capture guarded recursion. Birkedal et al modelled this modality via the internal logic of the topos of trees. We show that the semantics of the propositional fragment of this logic can be given by linear converse-well-founded intuitionistic Kripke frames, so this logic is a marriage of the intuitionistic modal logic KM and the intermediate logic LC. We therefore call this logic $\mathrm{KM}_{\mathrm{lin}}$. We give a sound and cut-free complete sequent calculus for $\mathrm{KM}_{\mathrm{lin}}$ via a strategy that decomposes implication into its static and irreflexive components. Our calculus provides deterministic and terminating backward proof-search, yields decidability of the logic and the coNP-completeness of its validity problem. Our calculus and decision procedure can be restricted to drop linearity and hence capture KM.Comment: Extended version, with full proof details, of a paper accepted to FoSSaCS 2015 (this version edited to fix some minor typos

Synthesis and characterization of hardened Cu-Fe-Ni-P alloy

In the manufacturing industry of electrical contacts, the prohibition of the use of toxic metals (Cd, Be), and desire to avoid the alloying with precious metals (Ag) has created a need for new alloys with good electrical conductivity and high mechanical properties at elevated temperatures. As a potentially useful material for this purpose, we have analyzed the continuously cast Cu-Fe-Ni-P alloy in various heat treatment conditions. Sequence of phase transformations during heat treatment was followed by 4 point D.C. electrical resistivity measuring method, and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Measurements of Vickers hardness and electrical conductivity after various heat treatment procedures indicate on high potential of Cu-Fe-Ni-P alloys as a material for electrical contacts

Structural and thermodynamic analysis of whiskers on the surface of grey cast iron

The paper focuses, first, on the characterization of the whiskers on the surface of grey cast iron and second, it gives an explanation of whiskers growth based on thermodynamic calculations. The whiskers were observed on the surface of hot plates for the electric stove after black-oxide-coating (blackening) performed the furnace at 650°C in order to produce a protective layer mainly of magnetite (Fe3O4). However, the whiskers caused brown spots on dark grey surface and thus, the surface was aesthetically damaged. The investigations confirmed that whiskers are of hematite (Fe2O3); however, the thermodynamic calculations present that hematite may be formed as a result of the oxidation of magnetite if the partial pressure of oxygen is increased during the blackening