Application of CLTD’s for High Resolution Mass Identification and for Stopping Power Measurements of Heavy Ions

An array of calorimetric low temperature detectors (CLTD’s) for energy sensitive detection of heavy ions was combined with time-of-flight (TOF) detectors to obtain a detector system for high resolution mass identification of low energy heavy ions. In addition the same setup was used to prove the ability of CLTD’s to be used in electronic stopping power measurements for heavy ions in matter. Experiments with 50?MeV ⁶³Cu and ⁶⁵Cu ions at the tandem accelerator at the MPI at Heidelberg, and with 25 to 250?MeV ²³⁸U ions at the UNILAC accelerator at GSI at Darmstadt have been performed. For ^63,65Cu at 50?MeV a mass resolution of Δm(FWHM)=0.9?amu, and for ²³⁸U in an energy range of 65 to 150?MeV a resolution of Δm(FWHM)=1.28?amu, was obtained. The results for stopping powers of ²³⁸U in carbon and gold are presented and compared with theoretical predictions and data from the literature.     

Strategies for Achieving Strength–Ductility Synergy in Face-Centered Cubic High- and Medium-Entropy Alloys

High- and medium-entropy alloys (HEAs/MEAs), also called as multicomponent alloys, are a new class of materials that break through the traditional alloy design concept based on single principal element. However, they do not break away from the magic spell of strength–ductility trade-off. Therefore, designing HEAs/MEAs with both high strength and high ductility still remains a great challenge nowadays. This article provides a review on the recent progress in mechanical properties of face-centered cubic (FCC) HEAs/MEAs. First, several traditional strengthening strategies are briefly reviewed, focusing on the strengthening mechanisms and the optimized mechanical properties. Subsequently, various novel strategies for achieving strength–ductility synergy in HEAs/MEAs are summarized, which include lowering the stacking fault energy, regulating the short-range order, promoting transformation-induced plasticity, and constructing heterogeneous microstructures. The basic ideas and related underlying mechanisms from these strategies are discussed. Finally, the current challenges and the future outlooks are emphasized and addressed systematically. In brief, the present review is expected to provide a useful guide for the design of HEAs/MEAs with superior mechanical properties.     

Normal-State Gap, Supercarrier Mass Anisotropy and Isotope Effects in La2−xSrxCuO4

Magnetization measurements have been performed on the oxygen-isotopeexchanged samples (¹⁶O and ¹⁸O) of the one-layer cuprate superconductorsLa_2?x Sr _x CuO₄ (0.06≤x≤0.20). We find that there is an oxygen-isotopeeffect on the effective supercarrier mass m**, which is huge for x=0.06,and reduced to a smaller value for x=0.15. We also find that there coexistsmall (bi)polarons and free carriers for x≥0.09, but only small (bi)polaronsare present for x≤0.09. The normal-state gap is related to the bipolaronbinding energy which is inversely proportional to x for 0.05≤x≤0.15. Theobserved isotope effects, supercarrier mass anisotropy, normal-state gap,and mid-infrared spectra for x≤0.09 can be quantitatively explained by the small(bi)polaron theory of superconductivity proposed by Alexandrov, Kabanov, andMott (AKM).     

Immobilization of Co(Ⅱ) Ions in Cement Pastes and Their Effects on the Hydration Characteristics

The immobilization of Co(Ⅱ) in various cement matrices was investigated by using the solidification/stabilization(S/S) technique.The different cement pastes used in this study were ordinary Portland cement in absence and presence of water reducing-and water repelling-admixtures as well as blended cement with kaolin.Two ratios of Co(Ⅱ) were used(0.5% and 1.0% by weight of the solid binder).The hydration characteristics of the used cement pastes were tested via the determination of the combined water content,phase composition and compressive strength at different time intervals up to 180 d.The degree of immobilization of the added heavy metal ions was evaluated by determining the leached ion concentration after time intervals extended up to 180 d.The leachability experiments were carried out by using two modes:the static and the semi-dynamic leaching processes.It was noticed that the concentration of the leached Co2+ ions in the static mode of leachability was lower than the solubility of its hydroxide in all the investigated cement pastes.     

Acceptance Criteria for Ultratrace HPLC-Tandem Mass Spectrometry: Quantitative and Qualitative Determination of Sulfonylurea Herbicides in Soil

Eight commonly used sulfonylureas (SUs: nicosulfuron, thifensulfuron methyl, metsulfuron methyl, sulfometuron methyl, chlorsulfuron, bensulfuron methyl, tribenuron methyl, and chlorimuron methyl) and deuterium-labeled nicosulfuron (nicosulfuron-d(6)), used as an internal standard, were isolated from soil by solvent extraction and identified under quantitative and qualitative ion spray LC/MS/MS conditions using the selected reaction monitoring (SRM) mode of acquisition. The lower level of quantitation for these SUs in soil was determined at the 0.05 ppb level using a TurboIonSpray adapted LC/MS interface without a precolumn split and optimizing MS/MS tuning conditions for individual SUs. The eight SUs were qualitatively identified and quantitatively determined in soil. The standard curve for each SU was linear from 0.05 to 10 ppb. This SRM LC/MS method demonstrates high sensitivity and high specificity for these SUs in soil and shows at least a 400-fold improvement in sensitivity over previous reports. Acceptance criteria for forensically valid data are suggested for qualitative SRM LC/MS experiments. These include HPLC retention time reproducibility (±2%), at least two and preferably three precursor-product ions selected, and relative abundance criteria for selected ions (±20% absolute).     

Some Three‐Dimensional Effects of Heat and Mass Transfer in a Fire within a Building

Results of a numerical investigation of heat and mass transfer at the initial stage of a fire within a building in combustion of a liquid fire load, performed with the use of a threedimensional mathematical field model, are presented. Formulas approximating the calculation results are proposed for estimation of the maximum time of operation of an opening to release the gas from the building and determination of the size of the zone within which a change in the position of the fire load causes no marked changes in the parameter of heat and mass transfer. Threedimensional inhomogeneities in the temperature and velocity fields, which have a profound impact on the problems of providing fire safety for buildings, are revealed.     

Normal-State Gap, Supercarrier Mass Anisotropy and Isotope Effects in La2?xSrxCuO4

Magnetization measurements have been performed on the oxygen-isotopeexchanged samples (¹⁶O and ¹⁸O) of the one-layer cuprate superconductorsLa_2–x Sr _x CuO₄ (0.06x0.20). We find that there is an oxygen-isotopeeffect on the effective supercarrier mass m**, which is huge for x=0.06,and reduced to a smaller value for x=0.15. We also find that there coexistsmall (bi)polarons and free carriers for x0.09, but only small (bi)polaronsare present for x0.09. The normal-state gap is related to the bipolaronbinding energy which is inversely proportional to x for 0.05x0.15. Theobserved isotope effects, supercarrier mass anisotropy, normal-state gap,and mid-infrared spectra for x0.09 can be quantitatively explained by the small(bi)polaron theory of superconductivity proposed by Alexandrov, Kabanov, andMott (AKM).     

Ultrahigh Mass Accuracy in Isotope-Selective Collision-Induced Dissociation Using Correlated Sweep Excitation and Sustained Off-Resonance Irradiation: A Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Case Study on the [M + 2H](2+) Ion of Bradykinin

Using electrospray ionization with a 9.4 T Fourier transform mass spectrometer, fragment ion spectra were acquired for a single isotopomer of doubly protonated bradykinin (molecular mass, 1059.6 Da). Correlated sweep excitation methods were applied to mass-select the single isotopomer (m/z = 530.8). Sustained off-resonance irradiation was used to activate and fragment the ions. The accuracy (in terms of m/z) in detection of the fragment ions was on average 1.2 ppm, making the assignments unambiguous. The methods employed would be generally applicable to ions in the mass range of approximately 50 Da to 50 kDa.     

A Monte Carlo Simulation to Evaluate the Pileup Effects on the Sensitivity to Neutrino Mass for the MARE Experiment

In this work, we have developed a Monte Carlo simulation as a tool to analyze the effect of the pulse-pileup on the sensitivity to the neutrino mass. It can be used as a guidance to fix the required properties in time response of the single pixel micro-calorimeter and to study the effects of noise on the pileup identification capability. This Monte Carlo simulation involves the numerical generation of noise in the time domain and bolometer thermal signals. The first goal is to determine the efficiency of discrimination algorithms in recognizing pulse pileup in dependence of the time separation between two pulses, their amplitude ratio and the structure of the noise. We have developed a code based on the Carson theorem able to generate noise with pre-assigned frequency power spectrum, while different software is used to generate thermal pulses with tracked time gap. These tools can be used to improve the discrimination techniques used in the analysis. The second goal consists of generating pulses with amplitudes distributed as the ¹⁸⁷Re beta energy spectrum and to study the effects on the neutrino mass sensitivity due to the distortions of this spectrum induced by pileup in different noise conditions.     

Feasibility Investigation of NbN Nanowires as Detector in Time-of-Flight Mass Spectrometers for Macromolecules of Interest in Biology (Proteins)

We are investigating the possibility of using NbN nanowires as detectors in time-of-flight mass spectrometers for investigation of macromolecules of interest in biology (proteins). NbN nanowires could overcome the two major drawbacks encountered so far by cryogenic detectors, namely the low working temperature in the mK region and the slow temporal response. In fact, NbN nanowires can work at 5 K and the response time is at least a factor 10–100 better than that of other cryogenic detectors. We present a feasibility study based on a numerical code to calculate the response of a NbN nanowire. The parameter space is investigated at different energies from IR to macromolecules (i.e. from eV to keV) in order to understand if larger value of film thickness and width can be used for the keV energy region. We also present preliminary experimental results of irradiation with X-ray photons of NbN to simulate the effect of macromolecules of the same energy.      

Application of Calorimetric Low Temperature Detectors (CLTD’s) for Precise Stopping Power Measurements of Heavy Ions in Matter

Calorimetric low temperature detectors (CLTD’s) have been included in a B-ToF setup, that has already been used several times to perform energy loss measurements at the accelerator laboratory of the University of Jyväskylä. The new experimental setup enabled a precise determination of stopping power data for 0.05–1 MeV/u \(^{131}\) Xe ions in carbon, nickel and gold. The results are presented and compared to data from literature and theoretical predictions. As a by-product, due to the excellent energy resolution of CLTD’s for heavy ions at low energies, an observation of channeling effects in very thin polycrystalline targets and a determination of the channeling energy loss for 0.1–0.5 MeV/u \(^{131}\) Xe-ions in Ni- and Au-absorbers was possible.     

Identifying the Pairing Mechanism in Fe�CAs Based Superconductors: Gaps and Isotope Effects

The temperature dependencies of the coupled superconducting gaps, observed in Fe?CAs based superconducting compounds is calculated and a universal temperature scaling observed which is only present if the coupled order parameters both have s-wave symmetry. Predictions for possible isotope effects on the superconducting transition temperature T _c are made if phonons are involved in the pairing or polaronic effects are of importance. Comparison to experimental data is given where these are available.     

Thunder®: A new frontier in research for smart materials

A powerful new family of high-performance actuators and sensors is shaking up the motion control industry. These solid state devices, called Thunder^®, are capable of delivering extraordinarily high displacement at substantial forces in a compact, energy efficient package. Based on a patented NASA invention, Thunder is a unique, rugged and adaptable member of the ‘smart’ materials group of products. This article describes this new enabling technology and highlights ongoing research.     

Algorithm of Combining Chromatography–Mass Spectrometry Untargeted Profiling and Multivariate Analysis for Identification of Marker Substances in Samples of Complex Composition

Inorganic Materials - A viral development of statistical data processing, computing capabilities, chromatography–mass spectrometry, and omics technologies (technologies based on the...     

Leveraging Ligand and Composition Effects: Morphology-Tailorable Pt–Bi Bimetallic Aerogels for Enhanced (Photo-)Electrocatalysis

Metal aerogels (MAs) are emerging porous materials displaying unprecedented potential in catalysis, sensing, plasmonic technologies, etc. However, the lack of efficient regulation of their nano-building blocks (NBBs) remains a big hurdle that hampers the in-depth investigation and performance enhancement. Here, by harmonizing composition and ligand effects, Pt- and Bi-based single- and bimetallic aerogels bearing NBBs of controlled dimensions and shapes are obtained by facilely tuning the metal precursors and the applied ligands. Particularly, by further modulating the electronic and optic properties of the aerogels via adjusting the content of the catalytically active Pt component and the semiconducting Bi component, both the electrocatalytic and photoelectrocatalytic performance of the Pt–Bi aerogels can be manipulated. In this light, an impressive catalytic performance for electro-oxidation of methanol is acquired, marking a mass activity of 6.4-fold higher under UV irradiation than that for commercial Pt/C. This study not only sheds light on in situ manipulating NBBs of MAs, but also puts forward guidelines for crafting high-performance MAs-based electrocatalysts and photoelectrocatalysts toward energy-related electrochemical processes.     

ICT for development in Tunisia: “Going the last mile”

This paper seeks to provide an overview of achievements and caveats related to ICT strategies for development in Tunisia. We go beyond a conventional approach of digital divide by considering exclusion from or inequalities in access to high-speed wired broadband infrastructure as a significant explanative variable in this area. Accordingly, we link the roles of ICT as enablers of new opportunities for socio-economic growth to the development of the last mile of the wired broadband infrastructure. Our analysis of the Tunisian ICT environment shows a prevalence of mobile technologies for Internet access and telephony as well as regional and social disparities in availability, access to and use of wired broadband technologies and services. Despite the real interest of Tunisian society and economy in using Internet, the range of broadband enabled-services and applications is rather limited. Additionally, the Tunisian case provides a promising perspective as there is a relatively well developed fibre backbone and potentially good opportunity for developing the last mile of wired infrastructure. We therefore suggest that it is necessary to develop a governmental policy in collaboration with the private sector to further develop the last mile section as well as to overcome weaknesses in the current regulatory frameworks.