Beitrag zur Gestaltung und Herstellung einer integrierten Mikropositionierungssystem

Modern positioning systems are significantly applied in many engineering fields dealing with products emerging from different technologies at macro-, micro- and nanoscale. These systems are the back-bone systems behind any manipulation task in these areas. Currently, miniaturization trend have led numerous scientific communities to realize down scaled versions of these systems with a footprint size up to few hundreds of millimeters. These miniature positioning systems are cost effective solutions in many micro applications. This thesis presents the development of a miniature positioning system integrated with a non-contact long range displacement sensor. The uniqueness of the presented positioning system lies in its simple design with ability to perform micrometer to millimeter level strokes with pre-embedded auto guidance feature. Its design consists of a mobile part driven with four electromagnetic linear motors. Each motor consists of a fixed two phase current carrying planar electric drive coil and permanent magnet array that is realized with 14 permanent magnets arranged in north-south configuration. In order to achieve smooth motion a four point contact technique with hemispherical glass beads has been adapted to minimize the adherence effect. The overall design of the planar positioning system have been optimized to achieve a footprint size of 80 mm × 80 mm. The device can deliver motion within working range of 10 mm × 10 mm in xy-plane with sub micrometer level resolution at a speed of 12 mm/s. The device is capable to deliver a rotation motion of ±11° about the z axis in the xy-plane. Secondly, in order to measure the displacement performed by the mobile part, a non-contact long range linear displacement sensor has been designed. The overall dimensions of the sensor were optimized using a geometrical model. The fabrication of the sensor has been carried out via microfabrication in silicon material to achieve compact dimensions, so that it could be integrated in the mobile part of the positioning system. The sensor is able to provide 30.8 nm resolution with a linear measurement range of 12.5 mm. At the end, a novel cross structure has been designed and fabricated using microfabrication with the perspective to integrate the long range sensor.Moderne Positioniersysteme werden in vielen aufstrebenden Bereichen der Technik eingesetzt. Die Produkte stammen hierbei aus unterschiedlichen Technologiebereichen, die den Makro-, Mikro- und Nano- Maßstab abdecken. Diese Systeme bilden die Basis jeder Manipulationsaufgabe, in diesen Bereichen. In jüngster Zeit hat der Miniaturisierungstrend dazu geführt, dass in zahlreichen wissenschaftlichen Bereichen immer kleinere Versionen von Systemen realisiert wurden. Die typischen Abmessungen wurden dabei auf einige hundert Millimeter reduziert. Diese Miniatur Positioniersysteme sind kostengünstige Lösungen in vielen Mikro Anwendungen. Die vorliegende Arbeit stellt die Entwicklung eines Miniatur-Positioniersystems dar, in welches ein berührungsloser Wegsensor für lange Distanzen integriert wurde. Die Einzigartigkeit dieses Positionierungssystems liegt in der Einfachheit der Konstruktion in Kombination mit der Fähigkeit Bewegungen vom Mikrometer bis zum Millimeter Bereich mittels einer eingebetteten Autopilotfunktion auszuführen. Das Design besteht aus einem beweglichen Teil, welches mit vier elektrischen Linearmotoren angetrieben wird. Jeder Motor besteht aus zwei Teilen: Einem planaren elektrisch angetriebenen Schlitten und einer Anordnung von Permanentmagneten. Die Anordnung ist mit 14 Permanentenmagneten in Nord-Süd Ausrichtung realisiert. Um eine sanfte Bewegung zu erreichen wird eine Vierpunktauflage mit halbkugelförmigen Glasperlen verwendet. Hierdurch werden Adhäsionseffekte minimiert. Das Positionierungssystem kann Bewegungen im Arbeitsbereich von 10 mm × 10 mm in der xy-Ebene mit Submikrometer Auflösung und einer Geschwindigkeit von 12 mm/s ausführen. Das Gerät ist in der Lage eine Drehbewegung von ±11° um die z-Achse in der xy-Ebene auszuführen. Weiterhin wurde, um die Verschiebung des beweglichen Teils zu messen, ein kontak tloser Langstrecken-Wegsensor entworfen. Die Gesamtabmessungen des Sensors wurden mit einem geometrischen Modell optimiert. Die Herstellung des Sensors wurde mittels Mikrostrukturierung in Silizium ausgeführt um eine kompakte Abmessung zu erreichen, so dass es in den beweglichen Teil des Positionierungssystems integriert werden konnte. Der Sensor erreicht eine Auflösung von 30,8 nm in einem linearen Messbereich von 12.5 mm. Am Ende der Arbeit wurde eine neue Kreuz-Struktur konzipiert und hergestellt, gleichfalls mit Hilfe der Mikrostrukturierungstechnik. Hieraus ergibt sich die Perspektive den Langstrecken Wegsensor problemlos zu integrieren

Methyl 2-amino-5-bromo­benzoate

In the title compound, C8H8BrNO2, the dihedral angle between the aromatic ring and the methyl acetate side chain is 5.73 (12)°. The mol­ecular conformation is stabilized by an intra­molecular N—H⋯O hydrogen bond, generating an S(6) ring. In the crystal, mol­ecules are connected by N—H⋯O inter­actions, generating zigzag chains running along the b-axis direction

2-Ethyl-2,3-dihydro-1,2-benzothia­zole-1,1,3-trione

In the title mol­ecule, C9H9NO3S, the bond lengths and angles fall within normal ranges. All nine ring atoms almost lie in a common plane (r.m.s. deviation 0.021 Å). In the crystal, symmetry-related mol­ecules are linked via C—H⋯O hydrogen bonds, forming a three-dimensional network

En bloc resection of a giant retroperitoneal liposarcoma: A surgical challenge

Liposarcomas are exceedingly rare entities that evoke malignant transformation of connective tissue and fat cells.These tumours occur throughout the soft tissues of the body, afflicting a myriad of regions. In the adult population, liposarcomas represent the most prevalent subtype of sarcomas, and often arise de novo. Retroperitoneal liposarcomas (RLS) are a ubiquitous subset of sarcomas that, due to their deep location in the hollow abdomen, can grow to astronomical proportions before manifesting any noticeable symptoms; a prompt diagnosis of RLS is therefore often rendered dilatory. We hereby delineate the case of a 43-year-old woman who presented with vague left hemiabdominal distention and discomfort. A subsequent computed tomography scan divulged a giant retroperitoneal growth impaling on and thus displacing the pancreas. A compartmental, en bloc resection was performed, with subsequent histopathology of the excised specimen revealing a well-differentiated liposarcoma. The surgical intervention was curative and led to an uneventful recovery. This paper highlights the pertinence of surgical management as an appropriate treatment modality for a complete resection of RLS

Performance Evaluation of Flexible Pavement Using Carbon Nanotubes and Plastic Waste as Admixtures

This paper investigates the properties of waste plastic film and carbon nanotubes modified asphalt mixes. The composed asphalt mixes have been evaluated for fatigue cracking and rutting. In this research, a total of 30 numbers of samples were prepared with different percentages of waste plastic films and carbon nanotubes from 0.1 to 0.4% and evaluated for dynamic stability and rutting using the wheel tracking machine. Results show that the addition of carbon nanotubes significantly increases the dynamic stability of asphalt and decreases the rutting up to a sufficient level as compared to plastic and conventional bitumen

4-Amino-2-chloro­benzoic acid

The title compound, C7H6ClNO2, crystallizes with two roughly planar mol­ecules in the asymmetric unit (r.m.s. deviations = 0.073 and 0.074 Å). The amine H atoms of the two mol­ecules have opposite orientations. In the crystal, mol­ecules are linked into dimers by pairs of O—H⋯O hydrogen bonds, generating R 2 2(8) loops. N—H⋯N and N—H⋯Cl hydrogen bonds link the dimers into a three-dimensional network. The crystal studied was found to be a racemic twin

2-(4-Chloro­benzamido)­acetic acid

In the crystal structure of the title mol­ecule, C9H8ClNO3, adjacent mol­ecules are arranged into centrosymmetric dimers through pairs of inter­molecular O—H⋯O inter­actions. Inter­molecular N—H⋯O hydrogen bonds link the dimers into a layer parallel to the bc plane. In the layer, mol­ecules are packed in a face-to-face π-stacked arrangment, showing π–π stacking inter­actions between the benzene rings with a centroid–centroid distance of 3.6884 (8) Å

4-Chloro-N-cyclo­hexyl­benzene­sulfonamide

The title compound, C12H16ClNO2S, adopts an L-shaped conformation, with the central C—S—N—C torsion angle being −78.0 (2)°. The cyclo­hexyl ring adopts a chair conformation. In the crystal, adjacent mol­ecules are connected by pairs of N—H⋯O hydrogen bonds around an inversion centre, forming cyclic dimers [graph set R 2 2(8)]

3-(Propan-2-yl­oxy)-1,2-benzothia­zole 1,1-dioxide

In the title compound, C10H11NO3S, the benzisothia­zole ring system is almost planar [maximum deviation = 0.030 (1) Å for the S atom]. The isoprop­oxy group is almost in the plane of the benzisothia­zole ring system [N—C—O—C = 4.5 (2)°] with one of its methyl groups in an anti­periplanar orientation relative to the benzisothia­zole ring system [C—C—O—C = −162.0 (2)°]

2-(Methoxy­carbon­yl)anilinium dihydrogen phosphate

The title compound, C8H10NO2 +·H2PO4 −, is a derivative of the naturally occurring compound methyl­anthranilate. The asymmetric unit comprises the 2-(methoxy­carbon­yl)anilinium cation and the dihydrogen phosphate anion. In the cation, the dihedral angle between the benzene ring plane and that through the methyl ester substituent is 22.94 (9)°. In the crystal, adjacent cations and anions form dimers through N—H⋯O and O—H⋯O hydrogen bonds, respectively. Additional N—H⋯O and C—H⋯O contacts result in a network of cation and anion dimers stacked down the b axis