669 research outputs found

    Business Analyse 2017 : eine empirische Untersuchung im deutschsprachigen Raum und Fallbeispiele aus Unternehmen

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    Der Sammelband Business Analyse 2017 stellt anhand von Befragungsergebnissen und Fallbeispielen die Funktionen und Rollen von Business-Analysten dar

    The Impact of Structural Pattern Types on the Electrochemical Performance of Ultra-Thick NMC 622 Electrodes for Lithium-Ion Batteries

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    An increase in the energy density on the cell level while maintaining a high power density can be realized by combining thick-film electrodes and the 3D battery concept. The effect of laser structuring using different pattern types on the electrochemical performance was studied. For this purpose, LiNi0.6Mn0.2Co0.2O2 (NMC 622) thick-film cathodes were prepared with a PVDF binder and were afterward structured using ultrafast laser ablation. Eight different pattern types were realized, which are lines, grids, holes, hexagonal structures, and their respective combinations. In addition, the mass loss caused by laser ablation was kept the same regardless of the pattern type. The laser-structured electrodes were assembled in coin cells and subsequently electrochemically characterized. It was found that when discharging the cells for durations of less than 2 h, a significant, positive impact of laser patterning on the electrochemical cell performance was observed. For example, when discharging was performed for one hour, cells containing laser-patterned electrodes with different structure types exhibited a specific capacity increase of up to 70 mAh/g in contrast to the reference ones. Although cells with a hole-patterned electrode exhibited a minimum capacity increase in the rate capability analysis, the combination of holes with lines, grids, or hexagons led to further capacity increases. In addition, long-term cycle analyses demonstrated the benefits of laser patterning on the cell lifetime, while cyclic voltammetry highlighted an increase in the Li-ion diffusion kinetics in cells containing hexagonal-patterned electrodes

    Laser patterning and electrochemical characterization of thick-film cathodes for lithium-ion batteries

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    Lithium-ion batteries (LIBs) are currently dominating the electrochemical storage sector due to their excellent properties such as high energy density, high power density, and long cycle lifetime. For automotive applications, current research focuses on the merger of two concepts: (i) the “thick film concept” which enables a high energy density due to a reduced amount of inactive materials, and (ii) the “three-dimensional (3D) battery concept”, which provides a high power density with improved interfacial kinetics at mass loadings ≄ 35 mg/cm2. Latter could be realized by applying ultrafast laser patterning of electrodes, which in turn includes an advanced 3D electrode design. Briefly, a rapid and homogeneous electrode wetting with liquid electrolyte can be induced, and besides a high capacity retention during long-term cyclability. Recently, various electrode designs such as line, grid, and hole structures have been reported for cathodes and anodes. However, the mass loss of those electrodes needs to be considered, since the cathode represents about 50 % of the total material costs of LIBs. Thus, the use of electrode structures with a high aspect ratio as well as a significantly reduced material removal is of great importance. In this work, 150 ÎŒm thick-film Li(Ni0.6Mn0.2Co0.2)O2 electrodes were manufactured by roll-to-roll tape-casting and subsequently structured with different pattern types using ultrafast laser radiation. Additionally, different designs were applied for laser patterning and the mass loss was minimized down to 7 %. Finally, the cathodes were assembled in half-cells for studying the impact of different laser patterning designs on electrochemical performance

    Re-thinking Decision-Making in Cybersecurity: Leveraging Cognitive Heuristics in Situations of Uncertainty

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    The prevailing consensus in cybersecurity is that individuals’ insecure behavior due to inadequate decision-making is a primary source of cyber incidents. The conclusion of this assumption is to enforce desired behavior via extensive security policies and suppress individuals’ intuitions or rules of thumb (cognitive heuristics) when dealing with critical situations. This position paper aims to change the way we look at these cognitive heuristics in cybersecurity. We argue that heuristics can be particularly useful in uncertain environments such as cybersecurity. Based on successful examples from other domains, we propose that heuristic decisionmaking should also be used to combat cyber threats. Lastly, we give an outlook on where such heuristics could be beneficial in cybersecurity (e.g., phishing detection or incident response) and how they can be found or created

    Electronic transport properties of electron- and hole-doped semiconducting C1b Heusler compounds: NiTi1−xMxSn (M=Sc, V)

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    The substitutional series of Heusler compounds NiTi1−xMxSn (where M=Sc,V and 0<x≀0.2) were synthesized and investigated with respect to their electronic structure and transport properties. The results show the possibility to create n-type and p-type thermoelectrics within one Heusler compound. The electronic structure and transport properties were calculated by all-electron ab initio methods and compared to the measurements. Hard x-ray photoelectron spectroscopy was carried out and the results are compared to the calculated electronic structure. Pure NiTiSn exhibits massive “in gap” states containing about 0.1 electrons per cell. The comparison of calculations, x-ray diffraction, and photoemission reveals that Ti atoms swapped into the vacant site are responsible for these states. The carrier concentration and temperature dependence of electrical conductivity, Seebeck coefficient, and thermal conductivity were investigated in the range from 10 to 300 K. The experimentally determined electronic structure and transport measurements agree well with the calculations. The sign of the Seebeck coefficient changes from negative for V to positive for Sc substitution. The high n-type and low p-type power factors are explained by differences in the chemical-disorder scattering-induced electric resistivity. Major differences appear because p-type doping (Sc) creates holes in the triply degenerate valence band at Γ whereas n-type doping (V) fills electrons in the single conduction band above the indirect gap at X what is typical for all semiconducting transition-metal-based Heusler compounds with C1b structure

    Learning from safety science: A way forward for studying cybersecurity incidents in organizations

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    In the aftermath of cybersecurity incidents within organizations, explanations of their causes often revolve around isolated technical or human events such as an Advanced Persistent Threat or a “bad click by an employee.” These explanations serve to identify the responsible parties and inform efforts to improve security measures. However, safety science researchers have long been aware that explaining incidents in socio-technical systems and determining the role of humans and technology in incidents is not an objective procedure but rather an act of social constructivism: what you look for is what you find, and what you find is what you fix. For example, the search for a technical “root cause” of an incident might likely result in a technical fix, while from a sociological perspective, cultural issues might be blamed for the same incident and subsequently lead to the improvement of the security culture. Starting from the insights of safety science, this paper aims to extract lessons on what general explanations for cybersecurity incidents can be identified and what methods can be used to study causes of cybersecurity incidents in organizations. We provide a framework that allows researchers and practitioners to proactively select models and methods for the investigation of cybersecurity incidents

    Cohesin mutations alter DNA damage repair and chromatin structure and create therapeutic vulnerabilities in MDS/AML

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    The cohesin complex plays an essential role in chromosome maintenance and transcriptional regulation. Recurrent somatic mutations in the cohesin complex are frequent genetic drivers in cancer, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Here, using genetic dependency screens of stromal antigen 2-mutant (STAG2-mutant) AML, we identified DNA damage repair and replication as genetic dependencies in cohesin-mutant cells. We demonstrated increased levels of DNA damage and sensitivity of cohesin-mutant cells to poly(ADP-ribose) polymerase (PARP) inhibition. We developed a mouse model of MDS in which Stag2 mutations arose as clonal secondary lesions in the background of clonal hematopoiesis driven by tet methylcytosine dioxygenase 2 (Tet2) mutations and demonstrated selective depletion of cohesin-mutant cells with PARP inhibition in vivo. Finally, we demonstrated a shift from STAG2- to STAG1-containing cohesin complexes in cohesin-mutant cells, which was associated with longer DNA loop extrusion, more intermixing of chromatin compartments, and increased interaction with PARP and replication protein A complex. Our findings inform the biology and therapeutic opportunities for cohesin-mutant malignancies
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