Publications by authors named "Gitzhofer F"

Article Synopsis
  • The study investigates how different punch coatings (Uncoated steel, CrN, ZrN, TiN, and Ultracoat) affect the sticking of microcrystalline cellulose (MCC) during the tableting process with a Manesty F3 press.
  • The analysis focused on surface properties like roughness, free energy, and functional groups, revealing that TiN and uncoated steel had the highest adhesion to MCC after pressing.
  • Results indicated that surfaces with higher Lewis base components in their surface free energy were more prone to sticking due to stronger interactions with evaporating water, and a high percentage of polar functional groups also contributed to this behavior.
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Punch sticking is a recurrent problem during the pharmaceutical tableting process. Powder moisture content plays a key role in the buildup of sticking; it evaporates due to increased tablet temperature, accumulates at the punch-tablet interface, and causes sticking through capillary force. This study investigated the effects of compaction pressure (CP), compaction speed (CS), and lubrication level (magnesium stearate (MgSt) ratio) on tablet surface temperature (TST) and tablet surface moisture content (TSMC).

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The moisture content of pharmaceutical powder is a key parameter contributing to tablet sticking during the tableting process. This study investigates powder moisture behavior during the compaction phase of the tableting process. Finite element analysis software COMSOL Multiphysics 5.

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Lightweight alloys have great importance for car manufacturers that aim to produce safer, lighter, and more environmentally friendly vehicles. As a result, it is essential to develop new lightweight alloys, with superior properties to conventional ones, respecting the demands of the market. Al and its alloys are good candidates for reducing the overall weight of vehicles.

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The behavior of Mo in contact with molten Al was modelled by classical molecular dynamics (CMD) simulation of a pure Mo solid in contact with molten Al at 1200 K using the Materials Studio. Results showed that no reaction or cross diffusion of atoms occurs at the Mo(s)-Al(l) interface, and that molten Al atoms exhibit an epitaxial alignment with the exposed solid Mo crystal morphology. Furthermore, the two phases {Mo(s) and Al(l)} are predicted to interact with weak van der Waals forces and give interfacial energy of about 203 mJ/m.

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The corrosion of refractories in contact with high temperature aluminum-magnesium alloys leads to contamination of the Al-Mg alloy products by solid impurities from degraded refractories. Where both the spinel and corundum phases form in the refractories, cracks are generated and propagated by diffusion of molten Al-Mg, resulting in severe corrosion. In this review paper, the corrosion phenomenon is discussed, and published work is summarized, supplemented by our recent experimental results.

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A study was done on the effect of temperature and catalyst pre-treatment on CO hydrogenation over plasma-synthesized catalysts during the Fischer⁻Tropsch synthesis (FTS). Nanometric Co/C, Fe/C, and 50%Co-50%Fe/C catalysts with BET specific surface area of ~80 m² g were tested at a 2 MPa pressure and a gas hourly space velocity (GHSV) of 2000 cm³ h g of a catalyst (at STP) in hydrogen-rich FTS feed gas (H₂:CO = 2.2).

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Substituted hydroxyapatite coatings with different ions (Mg, Na, K, Cl, F) have been developed by the induction suspension plasma spray process. Suspensions were prepared with sol-gel. The main objective of this study was to demonstrate that induction suspension plasma spray technology possesses high material composition flexibility that allows as-sprayed coatings to closely mimic natural bone composition.

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Calcium phosphate cements (CPCs) are of great interest for bone augmentation procedures. In these a hydraulic calcium phosphate paste is injected through a small bore needle into the bone. The injectability of these pastes is relatively poor, resulting into partial injection only.

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Calcium phosphate (CaP) cements are being increasingly used for minimally invasive hard tissue implantation. Possible approaches to improve the bad injectability of hydraulic calcium phosphate pastes have been discussed and investigated in a number of recent publications. However, the liquid-phase separation mechanism leading to the limited injectability has not yet been addressed.

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Measuring the porosity of materials by digital image analysis of micrographs is a well-established and convenient method for the testing of metallic samples. However, when applied to ceramic materials, this method has been shown to be much less reliable and poorly reproducible. The purpose of this present work is to clarify the reason for this deficiency, involving many porosity measurements, performed on plasma-sprayed zirconia, under systematically varied microscopic imaging conditions, and the porosities being calculated using various evaluation methods.

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Nanometer size hydroxyapatite (HA) crystals are prepared by a wet chemical precipitation method at different synthesis temperatures and with various reactant addition rates. The resulting aqueous suspensions are studied in terms of morphology (transmission electron microscope, specific surface area), phase (X-ray diffraction, electron diffraction and infrared spectroscopy) and rheological properties. This work shows that shape, size and specific surface area of the HA nanoparticles are very sensitive to the reaction temperature and also to the reactant addition rate.

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