High-Throughput screening of the CoRE MOF database to predict cross-linking of Metal-Organic Frameworks

Metall-organische Gerüststrukturen (engl. Metal-Organic Framework, MOF) sind poröse kristalline Materialien, die in den letzten Jahrzehnten immer mehr an Popularität gewonnen haben. Das liegt an erster Stelle an ihrer Vielseitigkeit, die eine Anwendung in unterschiedlichsten Anwendungsgebieten wie Gastrennung oder Gasspeicherung ermöglicht. Die Bausteine der MOFs sind zum einen die Metallzentren und zum anderen organische Linker, die zwei oder mehr Metallzentren miteinander verbinden. Durch diesen modularen Aufbau ist es möglich aus wenigen Bausteinen viele verschiedene neuartige kristalline Strukturen durch Variation zu erzeugen. Um MOFs als bioaktive Materialien nutzen zu können, ist es wünschenswert die Metalle herauszulösen, da eine etwaige toxische Reaktion durch die Metalle in vivo nicht gänzlich ausgeschlossen werden kann. Zudem ist die eingeschränkte Stabilität in wässriger Umgebung vieler MOF Strukturen ein weiterer Nachteil dieser Materialklasse für die Anwendung in der Biologie oder Medizin. Um die Vorteile der MOFs auch für solche Anwendungen nutzen zu können, wurde eine Strategie entwickelt in der die organischen Linker mit sekundären Linkern (cross-linker) quervernetzt werden (cross-linking). Dies erhöht die Stabilität des MOFs, sodass die Metalle anschließend problemlos entfernt werden können. Das Problem besteht darin die passenden cross-linker für eine bestimmte MOF Struktur zu finden. Zum einen muss der cross-linker ideal in die Struktur passen ohne sie zu verzerren, zum anderen sollte ein durchgängiges cross-linking der Struktur möglich sein, um Größen skalieren zu können. Der modulare Aufbau der MOFs hat aber auch zur Folge, dass die Zahl der theoretisch möglichen MOFs sehr stark zugenommen hat. Große Datenbanken mit zehntausenden solcher Strukturen sind entstanden. Den passenden MOF für einen gegebenen cross-linker zu finden gleicht nun der Suche nach der Nadel im Heuhaufen. In dieser Arbeit geht es gerade darum diese eine Nadel (oder mehrere) zu finden. Durch ein computergestütztes Screening soll eine MOF Datenbank durchleuchtet werden, um nach passenden MOF Kandidaten für einen gegebenen cross-linker zu suchen. Die Analyse und Auswertung dieser Datenbank gibt Aufschluss darüber, ob und wie eine MOF-Struktur sich quervernetzen lässt. Das Ergebnis des Screenings ist demnach eine Vorhersage einer MOF-Struktur, in der ein oder mehrere vorher bekannte cross-linker ideal hineinpassen. Die aus diesem Projekt vorhergesagten MOF cross-linker Kombinationen dienen als Vorlage für zukünftige experimentelle Arbeiten, deren Fokus auf die vielversprechendsten Kandidaten gelenkt wird

NASA Formal Methods Workshop, 1990

The workshop brought together researchers involved in the NASA formal methods research effort for detailed technical interchange and provided a mechanism for interaction with representatives from the FAA and the aerospace industry. The workshop also included speakers from industry to debrief the formal methods researchers on the current state of practice in flight critical system design, verification, and certification. The goals were: define and characterize the verification problem for ultra-reliable life critical flight control systems and the current state of practice in industry today; determine the proper role of formal methods in addressing these problems, and assess the state of the art and recent progress toward applying formal methods to this area

Constraint treatment techniques and parallel algorithms for multibody dynamic analysis

Computational procedures for kinematic and dynamic analysis of three-dimensional multibody dynamic (MBD) systems are developed from the differential-algebraic equations (DAE's) viewpoint. Constraint violations during the time integration process are minimized and penalty constraint stabilization techniques and partitioning schemes are developed. The governing equations of motion, a two-stage staggered explicit-implicit numerical algorithm, are treated which takes advantage of a partitioned solution procedure. A robust and parallelizable integration algorithm is developed. This algorithm uses a two-stage staggered central difference algorithm to integrate the translational coordinates and the angular velocities. The angular orientations of bodies in MBD systems are then obtained by using an implicit algorithm via the kinematic relationship between Euler parameters and angular velocities. It is shown that the combination of the present solution procedures yields a computationally more accurate solution. To speed up the computational procedures, parallel implementation of the present constraint treatment techniques, the two-stage staggered explicit-implicit numerical algorithm was efficiently carried out. The DAE's and the constraint treatment techniques were transformed into arrowhead matrices to which Schur complement form was derived. By fully exploiting the sparse matrix structural analysis techniques, a parallel preconditioned conjugate gradient numerical algorithm is used to solve the systems equations written in Schur complement form. A software testbed was designed and implemented in both sequential and parallel computers. This testbed was used to demonstrate the robustness and efficiency of the constraint treatment techniques, the accuracy of the two-stage staggered explicit-implicit numerical algorithm, and the speed up of the Schur-complement-based parallel preconditioned conjugate gradient algorithm on a parallel computer

A Review of global marketing with an illustration from Turkey

Ankara : The Department of Management and Graduate School of Business Administration of Bilkent Univ. , 1989.Thesis (Master's) -- Bilkent University, 1989.Includes bibliographical references leaves 47-48.Global marketing is a new topic in the marketing world. In this work a review of lobal strategy is done and as an illustration a study about four global products, the similarities and dissimilarities among their preferences and finally, liked and disliked factors about the products and their advertisement characteristics we reanalyzed from a global perspective . The study was conducted in Bilkent University and Hacettepe Medical Center.Pırnar, İgeM.S

Production of urban centralities for a global economy

Thesis (S.M. in Architecture Studies)--Massachusetts Institute of Technology, Dept. of Architecture, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 102-104).Keywords: Monument, CBD, Office tower, Podium, Global economy, China. The Central Business District (CBD) is the monument of the regional urban condition. A monument, which is expressive of financial competence and global connectivity. A monument for capital accumulation. The CBD of the global city is a representational tool manifesting bureaucratic capability and economic ambition. Historically originating in the United States, the CBD grew in an organic manner out the city's core and thus articulated a natural tie between congestion and financial growth - embodied in the typological invention of the skyscraper. Today the CBD of the developing city rises as a "pure" device of the planning and political authorities, a projection of the western paradigmatic "downtown" models into foreign contexts that fail to embody or represent the idea of their city or the collective domain of its inhabitants. Manifested as a cluster of towers, this urban and architectural project has seemingly detached itself from both context and content and appears to be increasingly self-sufficient. Yet while the CBD plays an essential role as a designed urban element that expresses financial progress, this thesis would contest its emphasis on the production of aesthetic contrast and uniqueness, and propose to consider it first and foremost as an operative device with real economic and social validity - not merely a representation of business but a business and an urban asset by its own right. Thus this thesis proposes a strategic revision of the typical CBD models by formulating a set of principles to correspond with key planning and design based challenges, namely issues of: Dimensional, Social, Symbolic and Organizational. These principles would hypothetically promote the mediation of contrast between the global capitalist drive for geographical expansion and the local circumstances that are often facing a process of radical transformation, while maintaining the necessary morphological flexibility and programmatic structuring, which is fundamental for the proper operationally of the CBD. China's current economic rise, which is both facilitated by and materialized in an intensive process of national scale urbanization and centralization, will be used as the geographic, economic and social context of this thesis. Operating within the gap between the automatic production of monumentality through the CBD and the geographic and political structure of the region, this thesis would conclude with a master plan proposal for a new CBD for the rapidly developing regional city of Chang-Zhu-Tan, the newly constructed capital of Hunan province.by Yaacov Eyal Ruthenberg.S.M.in Architecture Studie

Development of real-time cellular impedance analysis system

The cell impedance analysis technique is a label-free, non-invasive method, which simplifies sample preparation and allows applications requiring unmodified cell retrieval. However, traditional impedance measurement methods suffer from various problems (speed, bandwidth, accuracy) for extracting the cellular impedance information. This thesis proposes an improved system for extracting precise cellular impedance in real-time, with a wide bandwidth and satisfactory accuracy. The system hardware consists of five main parts: a microelectrode array (MEA), a stimulation circuit, a sensing circuit, a multi-function card and a computer. The development of system hardware is explored. Accordingly, a novel bioimpedance measurement method coined digital auto balancing bridge method, which is improved from the traditional analogue auto balancing bridge circuitry, is realized for real-time cellular impedance measurement. Two different digital bridge balancing algorithms are proposed and realized, which are based on least mean squares (LMS) algorithm and fast block LMS (FBLMS) algorithm for single- and multi-frequency measurements respectively. Details on their implementation in FPGA are discussed. The test results prove that the LMS-based algorithm is suitable for accelerating the measurement speed in single-frequency situation, whilst the FBLMS-based algorithm has advantages in stable convergence in multi-frequency applications. A novel algorithm, called the All Phase Fast Fourier Transform (APFFT), is applied for post-processing of bioimpedance measurement results. Compared with the classical FFT algorithm, the APFFT significantly reduces spectral leakage caused by truncation error. Compared to the traditional FFT and Digital Quadrature Demodulation (DQD) methods, the APFFT shows excellent performance for extracting accurate phase and amplitude in the frequency spectrum. Additionally, testing and evaluation of the realized system has been performed. The results show that our system achieved a satisfactory accuracy within a wide bandwidth, a fast measurement speed and a good repeatability. Furthermore, our system is compared with a commercial impedance analyzer (Agilent 4294A) in biological experiments. The results reveal that our system achieved a comparable accuracy to the commercial instrument in the biological experiments. Finally, conclusions are given and the future work is proposed