This technical paper delves into the creation and application of an enhanced mathematical model for semi crystalline thermoplastics based on the Pressure-Volume-Temperature (PVT) Two Domain Tait Equation. The model is designed to incorporate the impact of the cooling rate on the specific volume of the material. This is achieved by utilizing Flash differential scanning calorimetry (fDSC) measurements, thereby ensuring a direct correlation to the actual behavior of the material in reality.
View Article and Find Full Text PDFThe gas transport properties of thin film composite membranes (TFCMs) with selective layers of PolyActive™, polydimethylsiloxane (PDMS), and polyoctylmethylsiloxane (POMS) were investigated over a range of temperatures (10-34 °C; temperature increments of 2 °C) and pressures (1-65 bar abs; 38 pressure increments). The variation in the feed pressure of condensable gases CO and CH enabled the observation of peaks of permeance in dependence on the feed pressure and temperature. For PDMS and POMS, the permeance peak was reproduced at the same feed gas activity as when the feed temperature was changed.
View Article and Find Full Text PDFThe efficiency of using enriched CO from flue gas for large scale production of the green microalgae Chlorella sorokiniana in a bioenergy facade was studied. Using a membrane device, the enrichment of CO from heating system flue gas in the low pressure product gas was up to 49 vol% and the CO recovery was 62 %. With a static mixer the re-compressed product gas was applied to the culture medium with mean losses during cultivation of only 24 %.
View Article and Find Full Text PDFSweet cherry flesh cells burst when exposed to water but they do so in clusters indicating heterogeneity with respect to osmotic concentration, which depends on proximity to a minor vein. Water plays a key role in cracking in sweet cherry fruit. Magnetic resonance imaging has previously indicated preferential partitioning of water along veins.
View Article and Find Full Text PDFMembranes (Basel)
August 2021
Water-selective membrane reactors are proposed in the literature to improve methanol yield for a standalone reactor. However, the methanol productivity is not a precise metric to show the system improvement since, with this approach, we do not consider the amount of energy loss through the undesirable co-permeation of H, which could otherwise remain on the reaction side at high pressure. In other words, the effectiveness of this new technology should be evaluated at a process flowsheet level to assess its advantages and disadvantages on the overall system performance and, more importantly, to identify the minimum required properties of the membrane.
View Article and Find Full Text PDFNovel selective polymeric thin-film composite membranes (TFCMs) for applications at elevated temperatures were developed. Thin selective layers of the polyimides Matrimid 5218 and 6FDA-6FpDA were cast on a developed polybenzimidazole (PBI) porous support prepared by a phase inversion process. The TFCM properties were investigated with different gases in a wide temperature range, including temperatures up to 270 °C.
View Article and Find Full Text PDFPorous, porous/gutter layer and porous/gutter layer/selective layer types of membranes were investigated for their gas transport properties in order to derive an improved description of the transport performance of thin film composite membranes (TFCM). A model describing the individual contributions of the different layers' mass transfer resistances was developed. The proposed method allows for the prediction of permeation behaviour with standard deviations (SD) up to 10%.
View Article and Find Full Text PDFThree polyimides and six inorganic fillers in a form of nanometer-sized particles were studied as thick film solution cast mixed matrix membranes (MMMs) for the transport of CO₂, CH₄, and H₂O. Gas transport properties and electron microscopy images indicate good polymer-filler compatibility for all membranes. The only filler type thatdemonstrated good distribution throughout the membrane thickness at 10 wt.
View Article and Find Full Text PDFThe PolyActive™ thin film composite membrane (TFCM) has already been successfully applied for CO₂ separation tasks at feed pressures up to 10 bar. To investigate the applicability at higher pressures, measurements were undertaken with C₂H₄ containing gas mixtures with a composition comparable to the product stream of the oxidative coupling of methane process, as well as single gases up to a feed pressure of 30 bar. Furthermore, the permeances of the conducted gas mixture experiments were simulated.
View Article and Find Full Text PDFNovel selective ceramic-supported thin polyimide films produced in a single dip coating step are proposed for membrane applications at elevated temperatures. Layers of the polyimides P84, Matrimid 5218, and 6FDA-6FpDA were successfully deposited onto porous alumina supports. In order to tackle the poor compatibility between ceramic support and polymer, and to get defect-free thin films, the effect of the viscosity of the polymer solution was studied, giving the entanglement concentration (C*) for each polymer.
View Article and Find Full Text PDFIn this work, mixed-matrix membranes (MMMs) for gas separation in the form of thick films were prepared via the combination of the polymer Matrimid 5218 and activated carbons (AC). The AC particles had a mean particle size of 1.5 μm and a mean pore diameter of 1.
View Article and Find Full Text PDFWhether single session tDCS can impact upon cognition in healthy subjects is currently a heated debate against the background of inconsistent results. In view of the current methodological discussion concerning tDCS we developed an alternative approach to measure effects of single session tDCS on the Stroop task. The left DLPFC was stimulated in a pre-post design using a new electrode set-up (a 9 cm electrode was placed over the left DLPFC while a 35 cm was placed over the parieto-occipital cortex) contrasting anodal versus cathodal stimulation.
View Article and Find Full Text PDFDirect laser interference patterning (DLIP) is used to produce periodic line-like patterns on titanium surfaces. An Nd:YAG laser operating at 532 nm wavelength with a pulse duration of 8 ns is used for the laser patterning process. The generated periodic patterns with spatial periods of 5, 10, and 20 µm are produced with energy densities between 0.
View Article and Find Full Text PDFMixed-matrix membranes (MMMs) are promising candidates to improve the competitiveness of membrane technology against energy-intensive conventional technologies. In this work, MMM composed of poly(octylmethylsiloxane) (POMS) and activated carbon (AC) were investigated with respect to separation of higher hydrocarbons (C3+) from permanent gas streams. Membranes were prepared as thin film composite membranes on a technical scale and characterized via scanning electron microscopy (SEM) and permeation measurements with binary mixtures of n-C₄H10/CH₄ under varying operating conditions (feed and permeate pressure, temperature, feed gas composition) to study the influence on separation performance.
View Article and Find Full Text PDFBackground: Carryover experiments are widely used for clinical chemistry and immunochemistry analysers to evaluate and validate carryover effects. The experimental design is well described. However, there is no guideline on the statistical approach on data analysis, especially if absence of carryover has to be shown.
View Article and Find Full Text PDFCogn Affect Behav Neurosci
March 2014
Background: Different FT3 and FT4 assays report significantly different results. We compared the distribution of FT3 and FT4 in a cohort of Swiss patients measured with DxI 800, AxSYM, and Immulite 2000.
Methods: TSH, FT3, and FT4 values were measured in 1,938 serum samples.
Introduction: After measurement of the mean volumes of leukocyte subpopulations as well as the distribution widths (DW) of these volumes has become available, we investigated whether such morphometric leukocyte parameters are associated with a commonly used marker of cobalamin deficiency, i.e., holotranscobalamin (HoloTC).
View Article and Find Full Text PDFUnlabelled: BACKGROUND, OBJECTIVE: An international consensus conference underlined the importance of defining upper parathyroid hormone (PTH) reference values based on 25-OH-vitamin D [25(OH)D] to diagnose mild primary hyperparathyroidism. We determined the importance of this factor in a Belgian population.
Design, Patients, Methods: Intact PTH and 25(OH)D were measured in 261 healthy controls (18-65 years, winter/summer).
Background: To implement Lean Six Sigma in our central laboratory we conducted a project to measure single pre-analytical steps influencing turnaround time (TAT) of emergency department (ED) serum samples. The traditional approach of extracting data from the Laboratory Information System (LIS) for a retrospective calculation of a mean TAT is not suitable. Therefore, we used radiofrequency identification (RFID) chips for real time tracking of individual samples at any pre-analytical step.
View Article and Find Full Text PDFBackground: Folate, a water soluble B vitamin, is necessary for normal cell growth and DNA synthesis. A deficiency leads to megaloblastic anaemia and possible neurological sequelae. Since we receive samples from distant clinics and experience problems due to the long transit times to our laboratory, we carried out a folate stability study.
View Article and Find Full Text PDFBackground: This study was designed to investigate the clinical performance of the Access GI Monitor (Beckman Coulter) on the UniCel DxI 800, a method for CA19-9 antigen determination, and to compare with CA19-9 assay on the AxSYM system (Abbott).
Methods: 1,063 serum samples from unselected patients with different underlying diagnoses were tested with both methods. Passing-Bablok regression analysis and Bland Altman analysis was performed.
The influence of water temperature on the adsorption of natural dissolved organic matter (DOM) on activated carbon has not been investigated intensively yet. In this study, batch experiments with granular activated carbon (GAC) have been carried out at three temperatures (5 degrees C, 20 degrees C, 35 degrees C) using a humic acid model water and different types of surface water (lake, river, canal). Furthermore, the adsorption of an anthropogenic contaminant, atrazine, was quantified in the absence and presence of DOM.
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