Book review of "Life Strategies of Succulents in Deserts with Special Reference to the Namib Desert"

This is the published version

Technologieregelung bildet die Basis für einen robusten Kartontiefziehprozess

Karton ist ein aus nachwachsenden Rohstoffen hergestelltes Halbzeug, biologisch abbaubar und mit sehr guter Wiederverwertbarkeit. Damit stellt Karton eine zukunftsträchtige Grundlage für die Herstellung von Verpackungen für die Lebensmittel- und Konsumgüterproduktion dar. Schon heute werden in vielen Verpackungslösungen Kunststoffe durch naturfaserbasierte Halbzeuge ersetzt, um von den genannten Vorteilen zu profitieren. Um die Verbreitung dieses Naturstoffes weiter zu unterstützen, werden intelligente und effektive Herstellungsverfahren benötigt, die eine Massenfertigung von Packmitteln in hoher Qualität ermöglichen. [... aus der Einleitung

The Chronicle [July 15, 1998]

The Chronicle, July 15, 1998https://repository.stcloudstate.edu/chron/4332/thumbnail.jp

Water Potential Gradients between Old and Developing Leaves in Lithops (Aizoaceae).

Lithops plants consist of a pair of opposite succulent leaves inserted on a short stem. The apical meristem produces a new pair of leaves within the old one every growing season, recycling water from the old leaves. Since there are no data on water relations between the two pairs of leaves, we measured leaf water potential at different stages of development with a pressure chamber. Osmotic potential of cell sap was measured with a cryoscopic osmometer and turgor pressure was calculated indirectly. Leaf water potentials were never very low even though plants were not irrigated. In old leaves water potential ranged between -0.5 and -0.28 MPa. In young leaves water potential increased with size from -1.05 to -0.5 MPa and was always lower than in the corresponding old leaves. The water potential gradient between old and new leaves was steeper in the early stages of development (0.6 MPa) and gradually decreased (0.15 MPa) when young leaves had almost completed their expansion. Our data show that in Lithops water movement from old to young leaves occurs according to a water potential gradient. The maintenance of this gradient may be ascribed to differences in turgor pressure, due to the more elastic and plastic walls of cells of young leaves. The possibility to perform a complete life cycle without external water supply is an extreme adaptation to the arid environment where Lithops grows

Potenziale der Photogrammetrie bei der Vermessung von Verarbeitungsmaschinen

Um die Prozessstabilität in Verarbeitungsmaschinen auch bei hohen Ausbringungen bewerten und darauf aufbauend sicherstellen zu können ist eine geometrisch-kinematische Analyse des realen Verarbeitungsprozesses notwendig. Dazu wird im Beitrag ein optisches Hochgeschwindigkeits-Mehrkamera-Messsystem vorgestellt, mit dem auch schnelle Prozesse berührungslos analysiert werden können. Es wird gezeigt, wie durch die Zusammenführung von Bewegungsanalyse und Daten aus der Maschinensteuerung der Informationsgehalt und damit auch die Aussagefähigkeit von Messungen deutlich erhöht werden kann. Als Beispielprozess wird der intermittierende Transport kleinformatiger Stückgüter (z.B. Schokoladenriegel) gewählt

Derived... Northern Iowa Symphony Orchestra, February 13, 2019 [program]

Program of a music recital given by faculty, students, or guest artists from the School of Music at the University of Northern Iowa.https://scholarworks.uni.edu/recital_programs/1104/thumbnail.jp

Thermally Induced Clamping Force Deviations in a Sensory Chuck for Thin-Walled Workpieces

Deviations between nominal and actual tolerances are a challenging problem during turning processes of thin-walled workpieces. One main cause of these deviations is the clamping force applied by the turning chuck to hold the workpiece. Due to the low stiffness of thin-walled workpieces, large workpiece deformations can occur even when clamping forces are low. For this reason, the clamping force needs to be precisely adjusted. A possible approach are chucks with integrated actuators. As a result of the more direct power transmission, these chucks have a potentially higher clamping force accuracy compared to conventional external actuation. However, integrated actuators are additional heart sources resulting in thermal loads and thermally induced deformations of the chuck components. Due to the resulting mechanical distortion of the chuck system, the precise adjustment of clamping forces is not possible. Thus, this paper evaluates the thermally induced clamping force deviations on a novel turning chuck with four integrated electric drives. A test bench is used to analyse both a single drive and the combination of all four drives regarding the temperature effect on the clamping force adjustability. A clamping force deviation of up to 26% is observed. Based on the measured chuck temperature, a compensation method is introduced leading to a clamping force accuracy of 96.9%

Influence of XHV-adequate atmosphere on surface integrity

In aerospace engineering, high temperature alloys such as titanium are the preferred choice. However, machining of such materials remains a major challenge due to high process forces and process temperatures. Currently, machining is performed almost entirely in the presence of oxygen. This results in a process-inherent oxidation of the metal surface, which leads to higher tool wear during machining. By means of an oxygen-free machining undesirable oxidation reactions will be avoided and thus results in an extension of tool life. In addition, oxygen-free machining in an extreme high vacuum (XHV) adequate environment can influence the resulting workpiece surface and subsurface properties due to change in process forces and chip formation. In the present work, the influence of machining under air and XHV-adequate atmosphere is examined with regard to chip formation, workpiece surface topography and residual stresses. Significant differences can be seen in resulting surface integrity depending on the machining atmosphere