Glycerol valorization: dehydration to acrolein over silica-supported niobia catalysts

The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV–Vis, XPS, N2 adsorption), as well as with ammonia adsorption microcalorimetry. Good results are obtained with initial glycerol conversions of over 70% and with 50–70% selectivity to acrolein. We investigate the influence of changing the catalyst acid strength by varying the niobia content and catalyst calcination temperature. Glycerol conversion and acrolein selectivity depend on the surface acid strength. Catalyst deactivation by coking is also observed, but simple oxidative treatment in air restores the activity of the catalysts completely

The use of Wonnolas in controlling gastrointestinal nematode infections in sheep under traditional grazing management in Indonesia

Blocks containing 3% phenothiazine in solidified molasses (Wonnolas, Animeal Australia Ltd .) were tested to control gastrointestinal nematode infections and the effect on mineral status in sheep in villages in Cirebon, Indonesia. Two hundred and thirteen Javanese Thin Tail sheep which were grazed during the day and housed at night were divided into two groups on the basis of location . One group was allowed in an access to Wonnolas blocks when penned for 24 weeks while the other group remained untreated. The bodyweight was recorded and faecal samples were collected for egg counts and larval culture every four weeks. Sera and saliva samples were collected from 20 adult sheep in each group at weeks 0, 12 and 24 for mineral analysis by AAS and colorimetry. The results indicated that the mean egg counts of the treated group decreased from 576 epg to 123 epg and the percentage of sheep producing viable larvae decreased from 50% to 24%. In contrast egg counts of the control group increased from 768 epg to 4,840 epg and the percentage of sheep producing viable larvae increased from 65% to 84% over the same period . In the treated group the number of Haenronchus larvae declined significantly (36% to 6 %) and at the end of the trial Tiichostrongylus larvae predominanted in larval cultures (80%) . Mineral analysis revealed deficiencies in sodium and copper, low levels of zinc and normal levels of potassium, calcium, magnesium and phosphorus . Wormolas had a significant effect on sodium and zinc status but not on copper although sufficient levels of this element were available. Comparison of bodyweight gains showed a significantly (P0.05) higher rate of increase in the treated animals

Preceding rule induction with instance reduction methods

A new prepruning technique for rule induction is presented which applies instance reduction before rule induction. An empirical evaluation records the predictive accuracy and size of rule-sets generated from 24 datasets from the UCI Machine Learning Repository. Three instance reduction algorithms (Edited Nearest Neighbour, AllKnn and DROP5) are compared. Each one is used to reduce the size of the training set, prior to inducing a set of rules using Clark and Boswell's modification of CN2. A hybrid instance reduction algorithm (comprised of AllKnn and DROP5) is also tested. For most of the datasets, pruning the training set using ENN, AllKnn or the hybrid significantly reduces the number of rules generated by CN2, without adversely affecting the predictive performance. The hybrid achieves the highest average predictive accuracy

General Algorithm For Improved Lattice Actions on Parallel Computing Architectures

Quantum field theories underlie all of our understanding of the fundamental forces of nature. The are relatively few first principles approaches to the study of quantum field theories [such as quantum chromodynamics (QCD) relevant to the strong interaction] away from the perturbative (i.e., weak-coupling) regime. Currently the most common method is the use of Monte Carlo methods on a hypercubic space-time lattice. These methods consume enormous computing power for large lattices and it is essential that increasingly efficient algorithms be developed to perform standard tasks in these lattice calculations. Here we present a general algorithm for QCD that allows one to put any planar improved gluonic lattice action onto a parallel computing architecture. High performance masks for specific actions (including non-planar actions) are also presented. These algorithms have been successfully employed by us in a variety of lattice QCD calculations using improved lattice actions on a 128 node Thinking Machines CM-5. {\underline{Keywords}}: quantum field theory; quantum chromodynamics; improved actions; parallel computing algorithms

Very long optical path-length from a compact multi-pass cell

The multiple-pass optical cell is an important tool for laser absorption spectroscopy and its many applications. For most practical applications, such as trace-gas detection, a compact and robust design is essential. Here we report an investigation into a multi-pass cell design based on a pair of cylindrical mirrors, with a particular focus on achieving very long optical paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported longest path-length obtained with this type of cell configuration. We characterize the mechanical stability of the cell and describe the practical conditions necessary to achieve very long path-lengths

The Effect of Large Amplitude Fluctuations in the Ginzburg-Landau Phase Transition

The lattice Ginzburg-Landau model in d=3 and d=2 is simulated, for different values of the coherence length $\xi$ in units of the lattice spacing $a$, using a Monte Carlo method. The energy, specific heat, vortex density $v$, helicity modulus $\Gamma_\mu$ and mean square amplitude are measured to map the phase diagram on the plane $T-\xi$. When amplitude fluctuations, controlled by the parameter $\xi$, become large ($\xi \sim 1$) a proliferation of vortex excitations occurs changing the phase transition from continuous to first order.Comment: 4 pages, 5 postscript (eps) figure