Production of Gasoline and Gaseous Olefins by Catalytic Cracking of Pyrolysis Oil

Co-processing of biomass in petroleum refineries is a promising approach for biofuel production. In this work fluid catalytic cracking of residue from a co-pyrolysis with sawdust and VGO (1:2) was investigated. The pyrolysis oil residue with a boiling range bigger than 350 °C was mixed in different ratios with VGO and could be processed successfully up to 20 m%. Crack gas amounts increased while gasoline and total fuel yields decreased compared to VGO cracking. The gasoline obtained has a high octane number and is oxygen free

Die Krise in Ostasien

Bis in die jüngste Zeit waren die ostasiatischen Tigerstaaten wegen ihrer „beeindruckenden Wirtschaftspolitik" gelobt und als Vorbild für andere Volkswirtschaften dargestellt worden. Kam die Wirtschaftskrise in Ostasien völlig überraschend? Was löste die schweren wirtschaftlichen Turbulenzen schließlich aus? Welche wirtschafts- und währungspolitischen Konsequenzen sind aus der Krise zu ziehen? Welchen Einfluß hat sie auf die Weltwirtschaft und auf die deutsche Wirtschaft? --

Computergestützte Visualisierung eines human-embryonalen Gehirns

In der vorliegenden Arbeit wurde das 3-D-Modell des Gehirns eines frühen humanen Embryos angefertigt, des Weiteren eine 3-D-Software entwickelt, die es erlaubt, das Modell in Echtzeit manipulierbar darzustellen und es schließlich vollwertig stereoskopisch betrachten zu können. Diese Software wird Studierenden auf dem Server des Leibniz-Rechenzentrums zur Verfügung gestellt. Damit können sie am eigenen Rechner virtuelle 3-D-Modelle, die am Lehrstuhl III der Anatomischen Anstalt erarbeitet und bereit gestellt werden, plastisch (auch stereoskopisch) studieren. So besteht in Zukunft die Möglichkeit, die embryonale Entwicklung mit zeitgemäßen Methoden leicht verständlich zu veranschaulichen. Dem 3-D-Modell diente als Quellmaterial eine Schnittserie aus 574 Schichten eines menschlichen Embryos im Carnegie-Stadium 18. Die Schichten wurden über ein Mikroskop digitalisiert und am Computer wieder räumlich zueinander ausgerichtet. Um die ursprünglichen anatomischen Verhältnisse trotz der verzerrten Schnitte mit dem kommerziell verfügbaren Programm AmiraDev 3.0 möglichst korrekt herzustellen, wurde dieser elementare aber komplizierte Schritt durch selbst entwickelte Techniken unterstützt und sichtbar verbessert. Im so entstandenen Bilderstapel wurde das Gehirn markiert und dann zum virtuellen Modell trianguliert. Die hier entwickelte 3-D-Software erlaubt es, das willkürlich drehbare 3-D-Modell sowie andere Rekonstruktionen am Rechner anzuzeigen. Eine frei wählbare Schnittebene und die Transparenzfunktion geben Aufschluss über den inneren Aufbau des 3-D-Modells, z. B. über das Ventrikelsystem. In der Programmiersprache C++ wurden hocheffiziente, handoptimierte Bibliotheken für lineare Algebra und Computergrafik entwickelt, die eine ruckfreie Betrachtung ermöglichen. Im Hinblick auf Effizienz, Erweiterbarkeit und Fehlervermeidung wurde auf ein wohl überlegtes Software-Design mit sicherer Semantik Wert gelegt. Auch wenn ein virtuelles 3-D-Modell bereits einen besseren räumlichen Eindruck als eine plane Abbildung verschafft, kommt eine echte Tiefenwirkung erst durch stereoskopische Darstellung zustande. Diese wurde lege artis als asymmetrische perspektivische Projektion so implementiert, dass sie unkompliziert auf Tastendruck genutzt werden kann. Die ausgereifte Software beherrscht das Anaglyphenverfahren (Rot-Grün-Brille) genauso wie auch aufwendigere Projektionsverfahren. Die Arbeit stellt darüber hinaus in kurzer Form die für die Programmentwicklung relevanten mathematischen Grundlagen dar. Ferner wird ein Überblick über die im Internet verfügbaren, teils kommerziell vertriebenen Datensätze – speziell zur Embryologie – gegeben und das selbst entwickelte Darstellungsmodell mit seinen Vorteilen und den (selbst auferlegten) Beschränkungen in dieses Bezugssystem eingeordnet

New Solutions for Surface Reconstruction from Discrete Point Data by Means of Computational Intelligence

Surface reconstruction by means of triangulation of digitized point data leads to computational complex optimization problems. Here, deterministic algorithms often result in insufficient solutions or very long computation times. In this article, alternative methods of computational intelligence are discussed. A comparative analysis of two evolutionary algorithms applied to four different smoothness criteria for the triangulation of sparse point data sets is presented. optimally triangulated surfaces are the basis for many practical applications. The results presented here cover the efficient implementation and the influence of different triangulations for an adequate touch probe radius compensation (TPRC)

Dropping Out of Higher Education in Germany: Using Retrospective Life Course Data to Determine Dropout Rates and Destinations of Non-completers

In recent years, the high rates of higher education dropout have raised attention of education research and policy makers in Germany. However, due to data privacy legislation, it remains challenging to obtain information about the individual progress of students through higher education and the destinations of non-completers. With conventional administrative or cross-sectional data, it is not possible to distinguish non-completion from dropout, so that it mostly has to remain unclear if non-completers reach graduation elsewhere. This contribution uses the retrospective life course data of the NEPS starting cohort 6 to empirically disentangle non-completion and dropout of full-time students in higher education. We discuss the methodological challenges of conventional approaches and show how the advantages of retrospective life course data can be exploited for higher education research. We furthermore examine the destinations of non-completers and dropouts as well as the labour market returns of dropouts, using sequence data analyses and logistic regressions. Our results show that conventional designs possibly are prone to overestimate dropout rates. Longitudinal analyses of destinations after dropout reveal that the permeability between vocational training and higher education is not unidirectional. Vocational training is a relevant absorber of higher education dropouts, but at the same time, vocational qualifications that were gained prior to higher education work as safety-net that buffers labour market risks of dropouts

Bio-Gasoline from Jatropha Oil: New Applications for the FCC- Process

Jatropha curcas L. is a very drought-resistant plant, and jatropha oil can be ex-tracted from its seeds. Whilst not suitable for human consumption, we found that it is a promising feedstock for producing (bio)-gasoline. The oil was cracked in an inter-nally circulating FCC-reactor using a Grace Davison Ultima® catalyst. The total con-version was around 65%, with ca. 40% gasoline and ca. 25% crack gas (exact num-bers varied with reactor temperature). The gasoline has a RON \u3e 95 and oxy-gen \u3c 0.3% m. The crack-gas consisted of ca. 35% propylene, ca. 13% 1-butene and ca. 6% ethylene

The Interplay Between Instructional Pace, Skill Externalities, and Student Achievement: An Empirical Assessment

This article empirically validates a theoretical model from Kiss (B.E. J Econ Anal Policy 17:1–10, 2017) that addresses the transmission channels through which increases in peer achievement levels may affect other students’ achievement. In his model, a higher share of better students has two effects: first, weaker students benefit from skill externalities generated by their better classmates. At the same time, however, better students further induce teachers to instruct at a more demanding pace. Based on these two effects, I derive three hypotheses and test them on data on German secondary school students. Empirical findings are consistent with the model’s predictions: increases in the share of better classmates (a) are always beneficial for good students, (b) may hurt weak students, and (c) boost weak students’ achievement if the extent of interaction between better and weaker students is high. Taken together, these findings suggest that encouraging better and weaker students to interact more could be Pareto-improving

Bio-Gasoline from Jatropha Oil: New Applications for the FCC- Process

Jatropha curcas L. is a very drought-resistant plant, and jatropha oil can be ex-tracted from its seeds. Whilst not suitable for human consumption, we found that it is a promising feedstock for producing (bio)-gasoline. The oil was cracked in an inter-nally circulating FCC-reactor using a Grace Davison Ultima® catalyst. The total con-version was around 65%, with ca. 40% gasoline and ca. 25% crack gas (exact num-bers varied with reactor temperature). The gasoline has a RON \u3e 95 and oxy-gen \u3c 0.3% m. The crack-gas consisted of ca. 35% propylene, ca. 13% 1-butene and ca. 6% ethylene

Embossing of a screw thread and TCP granules enhances the fixation strength of compressed ACL grafts with interference screws

Purpose: Fixation of soft tissue grafts with interference screws relies on the friction of the graft between the screw and the bone tunnel. The goal of this study was to precondition such grafts by mechanical compression in order to reduce anticipated and undesired viscoelastic adaptation of the graft to screw pressure. Further, the otherwise slippery graft surface was modified with impressed tricalcium phosphate granules (TCP) to improve friction and mechanical hold. Methods: Fresh flexor digitorum tendons from young bovines were used to create bundles with a diameter of 8-9mm and were divided into 10 groups to compare the pullout strength and bone damage in a variety of construct scenarios. Specifically, the effects of graft precompression to reduce preimplantation graft diameter were investigated. Further the effects of impressing TCP granules and/or a screw thread into the tendon surface during the compression process were studied. Results: In sawbone tests, radial graft compression allowed for a smaller bone tunnel (7mm), but resulted in a significantly lower pullout strength of 174N (95% CI: 97, 250), compared with controls [315N (204, 426)]. In contrast, TCP coated [402N (243, 561)], screw embossed grafts [458N (302, 614)], and the combination of TCP and embossing [409N (274, 543)] achieved higher pullout strengths when compared to the standard technique. In porcine bone, untreated grafts using an 8mm screw pulled out at 694±93N, significantly higher loads were required to pullout compressed grafts with or without TCP coating (870±74 and 878±131N), yet fixed with a 7mm screw. Conclusion: Modification of the tendon graft surface has a large influence on the biomechanical performance of interference screw fixation and results in less bone damage inflicted during insertion to a smaller tunnel diameter, while simultaneously achieving superior pullout strengt