Novel composite hollow fibre gas separation membranes with high selectivity and improved solvent resistance

Composite gas separation membranes with a 0.1–3 μm thick film of Hyflon AD 60X on a porous hollow fibre ultrafiltration membrane support of amorphous poly(ether ether ketone), were prepared. The influence of the coating conditions on the film thickness and on the pure gas transport properties was studied. The gas transport properties were related to the film thickness and to the morphology of the supporting UF membrane.     

Beyond 9-ODA: SEX Pheromone Communication in the European Honey Bee Apis mellifera L.

The major component of the mandibular gland secretion of queen honeybees (Apis mellifera L.), 9-ODA ((2E)-9-oxodecenoic acid), has been known for more than 40 yr to function as a long-range sex pheromone, attracting drones at congregation areas and drone flyways. Tests of other mandibular gland components failed to demonstrate attraction. It remained unclear whether these components served any function in mating behavior. We performed dual-choice experiments, using a rotating drone carousel, to test the attractiveness of 9-ODA compared to mixtures of 9-ODA with three other most abundant components in virgin queen mandibular gland secretions: (2E)-9-hydroxydecenoic acid (9-HDA), (2E)-10-hydroxydecenoic acid (10-HDA), and p-hydroxybenzoate (HOB). We found no differences in the number of drones attracted to 9-ODA or the respective mixtures over a distance. However, adding 9-HDA and 10-HDA, or 9-HDA, 10-HDA, and HOB to 9-ODA increased the number of drones making contact with the baited dummy. On the basis of these results, we suggest that at least 9-HDA and 10-HDA are additional components of the sex pheromone blend of A. mellifera.     

STOCHASTIC FINITE-ELEMENT ANALYSIS OF COUPLED HEAT AND MASS TRANSFER PROBLEMS WITH RANDOM FIELD PARAMETERS

A first-order perturbation algorithm for the computation of mean values and variances of transient temperature and moisture fields during coupled heat and mass transfer problems with random field parameters has been developed and implemented. The algorithm is based on the Galerkin finite-element discretization of Luikov's heat and mass transfer equations for capillary porous bodies and is computationally less demanding than the Monte Carlo method. The algorithm has been programmed in MATLAB and applied to a published test case of a drying process for soybean kernels. The simulations indicate that the stochastic fluctuations of the thermophysical properties and the process conditions may cause a considerable level of uncertainty in the predicted temperatures and moisture contents inside the product.     

Deriving control parameter settings from process models to control capsule fillers integrated into continuous manufacturing

The aim of this work was to investigate the mean fill weight control of a continuous capsule-filling process, whether it is possible to derive controller settings from an appendant process model. To that end, a system composed out of fully automated capsule filler and an online gravimetric scale was used to control the filled weight. This setup allows to examine challenges associated with continuous manufacturing processes, such as variations in the amount of active pharmaceutical ingredient (API) in the mixture due to fluctuations of the feeders or due to altered excipient batch qualities. Two types of controllers were investigated: a feedback control and a combination of feedback and feedforward control. Although both of those are common in the industry, determining the optimal parameter settings remains an issue. In this study, we developed a method to derive the control parameters based on process models in order to obtain optimal control for each filled product. Determined via rapid automated process development (RAPD), this method is an effective and fast way of determining control parameters. The method allowed us to optimize the weight control for three pharmaceutical excipients. By conducting experiments, we verified the feasibility of the proposed method and studied the dynamics of the controlled system. Our work provides important basic data on how capsule filler can be implemented into continuous manufacturing systems.     

Eine Formel verändert die Welt

The capacity formula for the Additive White Gaussian Noise (AWGN-) channel is taken for an example to demonstrate the extreme importance of Information Theory of C.E. Shannon for the transition from the Industrial Age to the Information Age. Exemplarily, typical ways of finding basic theorems in Information Theory are shown by means of two mathematical concepts. Simple relationships between information and energy as well as fundamental existence/nonexistence bounds for analogous and digital communication schemes are derived from the capacity formula. General comments on the importance of fundamental theories for the progress in technologies and on the rule of humanities in this process conclude the paper.     

Enhanced expoxidation activity of Ti-mesoporous catalysts containing organic–inorganic porewall

Surfactant templated Ti-containing organic–organic mesoporous catalysts which were synthesized from one step co-condensation of the precursors, showed enhanced liquid phase cyclohexene epoxidation activity and greater deactivation resistance than the parent Ti-MCM-41, with tert-butyl hydroperoxide as oxidant. The order of reactivity observed was Ti-MCM-41-phenylene > Ti-MCM-41-biphenylene > Ti-MCM-41-ethylene > Ti-MCM-41. In the presence of water, the Ti-MCM-41-phenylene catalyst showed up to 3.5-fold enhancement in activity over Ti-MCM-41. The enhancement in catalytic activity was attributed to improvement in surface hydrophobic characteristic from the incorporation of organic functionalities.     

First Tandem Asymmetric Conjugate Addition of Alkenyl Nucleophiles and Silyl Trapping of the Intermediate Enolates

The tandem asymmetric conjugate addition of alkyl or aryl groups to enones and subsequent silyl trapping has already been achieved and yields valuable silyl enol ethers. Herein, the first method for the respective addition of alkenyl groups is reported, which is based on a rhodium(I)‐catalyzed addition of readily available alkenylzirconocenes. As prerequisite for silyl trapping, the initially formed enolates have to be transmetalated from zirconium to lithium by treatment with methyllithium prior to addition of the silyl chloride. Starting from 5‐ to 7‐membered cycloalkenones, the respective silyl enol ethers were obtained in excellent yields and ≥93% ee; an acyclic substrate furnished a moderate enantioselectivity. Besides trimethylsilyl chloride, the silylation was also performed with tert‐butyldimethylsilyl chloride, and the synthetic scope was evaluated by employing five different alkenyl groups. Moreover, the mechanism of this sequence was elucidated by ¹H NMR studies, and the efficiency of catalyst control was exemplified by synthesis of a cis‐3,5‐disubstituted cyclohexanone which, due to strong substrate control, cannot be obtained by copper‐catalyzed conjugate addition.

     

Modifications in the bulk and the surface of unbleached lignocellulosic fibers induced by heat treatment without water removal: effects on tensile properties of unrefined kraft pulp

The effects of heating lab cooked never dried kraft pulp from pine and spruce at 5 % consistency to 80, 100 and 120 °C in a pressurized vessel were evaluated based on various fiber and sheet properties. The settings of pH and conductivity in the lab trial were chosen in accordance with operations such as oxygen delignification, alkaline extraction, washing or storage of pulp in an integrated paper mill. It was found that the tensile strength was reduced steadily with increasing temperature. Nuclear magnetic resonance spectroscopy showed that fiber crystallinity and pore size increased at high temperatures compared to the unheated reference. Crystallinity most likely affected the fiber flexibility and thus resulted in less and weaker fiber–fiber bonds. Atomic force microscopy indicated that the amount of precipitated lignin granules on the fiber surface was reduced with increasing temperature. The roughness of the fiber surface did not significantly change with temperature and hence did not negatively influence the tensile strength. It was remarkable that a so called reversed latency was observed. Instead of a decrease in fiber curl with temperature, the fiber became significantly more curled. A large portion of the losses in tensile strength was attributed to the increase in fiber curl and leaching of hemicelluloses from the fiber wall.     

A Chiral Microporous Polymer Network as Asymmetric Heterogeneous Organocatalyst

Microporous polymer networks, composed of structure‐directing monomers (tectons), can exhibit high permanent surface area and porosity. By choice of suitable tectons various functionalities can be introduced into such networks. Here we introduce chiral BINOL derivatives as novel tectons to generate microporosity in polymer networks. The use of such monomers enables the formation of networks composed solely out of enantiomerically pure compounds. This porous network can be used as a heterogeneous organocatalyst in asymmetric reactions and gives higher enantioselectivty than the homogeneous reaction.