Ti50Cu25Ni20Sn5 (at.%) powder was subjected to high-energy ball milling at room temperature and -78 ?C. As a function of the milling time, evaluation of phases, morphology, and the refinement of ...grain size were investigated by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and laser-diffraction particle size analysis (PSA). The transformation of the crystalline structure into an amorphous structure and then the transformation into a nanocrystalline structure during further milling was detected. The stress-induced martensitic transformation occurred after 30 min milling time at both temperatures, the cubic Cu(Ni,Cu)Ti2 phase transformed into the orthogonal structure. The hardness value of powders after 150 min milling time increased from 506 to 780 HV0.01. The milling temperature did not significantly influence the amount of amorphous fraction (33-36 wt.%), however, the composition of amorphous content was more influenced by temperature. The interval of crystallite size was between 1.2 and 11.7 nm after 180 min of milling. The amount and the cell parameters of the Sncontaining phases were different for the two milling experiments because the diffusion coefficients of the Sn atom differed to a large extent.
In this paper we report on a novel, large area method to produce SiC nano- and micro patterns at room temperature where the compound and pattern formation happens in one step. We have previously ...demonstrated that SiC can be produced by noble gas irradiation of a Si/C multilayer system utilizing the ion beam mixing (IBM) taking place at the interfaces. Here we show that by applying IBM in samples masked in any desired way patterned SiC surfaces, micro and nanostructures, result. Two different masking layers were applied to demonstrate the capabilities of the method; a Langmuir-Blodgett (LB) film of 590 nm silica nanoparticles and a lithographic grid, of 2 μm periodicity, mounted to the surface of a Si/C multilayer system. The systems were irradiated by Xe+ ions of 120 keV. The samples before and after IBM have been analyzed by AFM, SEM and AES depth profiling, proving that patterning occurred: the non-covered areas became SiC rich regions, while the covered areas remained untouched. As a possible application for the patterned samples, the gold-coated LB patterned nanostructure was used for surface enhanced Raman spectroscopic detection of an organic dye molecule (R6G) demonstrating the efficiency of IBM for producing SERS substrates consisting of a very stable compound like SiC.
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•A novel method was demonstrated for the production of SiC micro and nanopatterns.•Patterning and SiC compound formation happened in one step at room temperature.•The SiC formation was proved by AES depth profiling.•Two different structures were presented.•The method can be considered as a possibility to fabricate SERS substrates.
Recent implementations of QSAR modelling software provide the user with numerous models and a wealth of information. In this work, we provide some guidance on how one should interpret the results of ...QSAR modelling, compare and assess the resulting models, and select the best and most consistent ones. Two QSAR datasets are applied as case studies for the comparison of model performance parameters and model selection methods. We demonstrate the capabilities of sum of ranking differences (SRD) in model selection and ranking, and identify the best performance indicators and models. While the exchange of the original training and (external) test sets does not affect the ranking of performance parameters, it provides improved models in certain cases (despite the lower number of molecules in the training set). Performance parameters for external validation are substantially separated from the other merits in SRD analyses, highlighting their value in data fusion.
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•WC coating layers with excellent corrosion resistance were produced by IBM.•The corrosion resistance depends on the effective areal density of WC.•The effective areal density shows ...sharp changes as a function of irradiation fluence.•The effective areal density can be predicted by TRIDYN simulations.
Tungsten carbide (WC) belongs to the class of protective coatings due to its good mechanical properties and corrosion resistance. Herein WC-rich coating layers have been produced by irradiating C/W multilayers with noble gases at room temperature. The in-depth concentration distributions after ion irradiation have been measured by Auger electron spectroscopy depth profiling. The corrosion resistance of the formed layers has been tested in 3.5 wt% NaCl solution. It has been shown that the growth of the WC-rich layer started at the interfaces and with increasing fluence the separately growing layers coalesced. With the coalescence of the layers the corrosion resistance of the system suddenly increased. To describe this phenomenon the term effective areal density has been introduced. If the effective areal densities of WC were lower and higher than 550 (1/nm2) and 1200 (1/nm2), the corrosion current densities were 0.5 and 0.08 (µA/cm2), resp. The in-depth distribution of the WC-rich layer and thus the corrosion resistance could be tailored by varying the projectiles, fluences, energies and initial layer structure. The maximum corrosion resistance found was better than that of stainless steel and WC cermet. The effective areal densities could be predicted by TRIDYN simulations allowing the design of corrosion resistive coatings.
A concise account of the physicochemical properties of morphine and its derivatives of therapeutic interest is provided. Such properties include macroscopic and microscopic acid/base parameters, ...lipophilicity, solubility, permeability that all influence the fate of drugs in the body. The dependence of these parameters on pH is discussed and subsequent implications in drug administration and formulation are presented.
Prediction performance often depends on the cross- and test validation protocols applied. Several combinations of different cross-validation variants and model-building techniques were used to reveal ...their complexity. Two case studies (acute toxicity data) were examined, applying five-fold cross-validation (with random, contiguous and Venetian blind forms) and leave-one-out cross-validation (CV). External test sets showed the effects and differences between the validation protocols. The models were generated with multiple linear regression (MLR), principal component regression (PCR), partial least squares (PLS) regression, artificial neural networks (ANN) and support vector machines (SVM). The comparisons were made by the sum of ranking differences (SRD) and factorial analysis of variance (ANOVA). The largest bias and variance could be assigned to the MLR method and contiguous block cross-validation. SRD can provide a unique and unambiguous ranking of methods and CV variants. Venetian blind cross-validation is a promising tool. The generated models were also compared based on their basic performance parameters (r
2
and Q
2
). MLR produced the largest gap, while PCR gave the smallest. Although PCR is the best validated and balanced technique, SVM always outperformed the other methods, when experimental values were the benchmark. Variable selection was advantageous, and the modelling had a larger influence than CV variants.
The efficiency of the Data Acquisition (DAQ) of the Compact Muon Solenoid (CMS) experiment for LHC Run 2 is constantly being improved. A significant factor affecting the data taking efficiency is the ...experience of the DAQ operator. One of the main responsibilities of the DAQ operator is to carry out the proper recovery procedure in case of failure of data-taking. At the start of Run 2, understanding the problem and finding the right remedy could take a considerable amount of time (up to many minutes). Operators heavily relied on the support of on-call experts, also outside working hours. Wrong decisions due to time pressure sometimes lead to an additional overhead in recovery time. To increase the efficiency of CMS data-taking we developed a new expert system, the DAQExpert, which provides shifters with optimal recovery suggestions instantly when a failure occurs. DAQExpert is a web application analyzing frequently updating monitoring data from all DAQ components and identifying problems based on expert knowledge expressed in small, independent logic-modules written in Java. Its results are presented in real-time in the control room via a web-based GUI and a sound-system in a form of short description of the current failure, and steps to recover.
The upgraded High Luminosity LHC, after the third Long Shutdown (LS3), will provide an instantaneous luminosity of 7.5 × 1034 cm−2s−1 (levelled), at the price of extreme pileup of up to 200 ...interactions per crossing. In LS3, the CMS Detector will also undergo a major upgrade to prepare for the phase-2 of the LHC physics program, starting around 2025. The upgraded detector will be read out at an unprecedented data rate of up to 50 Tb/s and an event rate of 750 kHz. Complete events will be analysed by software algorithms running on standard processing nodes, and selected events will be stored permanently at a rate of up to 10 kHz for offline processing and analysis. In this paper we discuss the baseline design of the DAQ and HLT systems for the phase-2, taking into account the projected evolution of high speed network fabrics for event building and distribution, and the anticipated performance of general purpose CPU. Implications on hardware and infrastructure requirements for the DAQ "data center" are analysed. Emerging technologies for data reduction are considered. Novel possible approaches to event building and online processing, inspired by trending developments in other areas of computing dealing with large masses of data, are also examined. We conclude by discussing the opportunities offered by reading out and processing parts of the detector, wherever the front-end electronics allows, at the machine clock rate (40 MHz). This idea presents interesting challenges and its physics potential should be studied.
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