Catalytic conversion of sodium lignosulphonate to vanillin –engineering aspects. Part 1 Effect of processing conditionson vanillin yield and selectivity

The commercial production of vanillin from sodium lignosulfonate under highly alkaline conditions, catalyzed by Cu2+ at elevated temperature and pressures up to 10 bar, has been simulated in a 3-L stirred reactor. Initially, the process was operated in the presence of nitrogen in dead-end mode, and it was shown that vanillin and vanillic acid were formed by hydrolysis at temperatures of 120, 140, and 160 °C. At the two higher temperatures, the amount of vanillin produced was the same. Subsequently, experiments were conducted at the same elevated pressures and temperatures with addition of air or oxygen-enriched air once the temperature in the reactor had reached temperatures similar to those used when only hydrolysis occurred. In this case, the concentration of vanillin at 140 and 160 °C was equal to that due to hydrolysis, and the subsequent 2-fold increase was due to oxidation. In addition, both vanillic acid and acetovanillone (which has rarely been reported) were produced, as was hydrogen. Thus, for the first time, it has been shown that the production of vanillin (and other compounds) from sodium lignosulfonate at elevated temperatures involves hydrolysis and oxidation, with hydrolysis starting at just above 100 °C, that is, much lower than has previously been reported. Approximately 50% is produced by each mechanism. In addition, the orders of the reactions of the different steps were estimated, and the reaction mechanisms are discussed.

Effect of the P-glycoprotein inhibitor, R(+)-verapamil on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by the inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant and Cullompton TCBZ-susceptible fluke isolates were used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R-VPL]. In the first experiment, flukes were initially incubated for 2 h in R-VPL (100 µM), then incubated for a further 22 h in R-VPL+triclabendazole sulphoxide (TCBZ.SO) (50 µg/ml, or 0.1327 µM). For controls, flukes were incubated for 24 h in R-VPL and TCBZ.SO on their own. In a second experiment, flukes were removed from the incubation media following cessation of movement. In the third experiment, Sligo flukes were incubated in lower concentrations of R-VPL (10 µM) and TCBZ.SO (15 µg/ml, or 0.0398 µM). Morphological changes resulting from drug treatment and following Pgp inhibition were assessed by means of scanning electron microscopy. Incubation in R-VPL alone had minimal effect on either isolate. After treatment with TCBZ.SO alone, there was greater surface disruption to the Cullompton than Sligo isolate. However, combined treatment of R-VPL+TCBZ.SO led to more severe surface changes to the Sligo isolate than with TCBZ.SO on its own; this potentiation of drug activity was not seen with the Cullompton isolate. The phenomenon was evident at both concentrations of TCBZ.SO. Inclusion of R-VPL in the incubation medium also reduced the time taken for the flukes to become inactive; again, this effect was more distinct with the Sligo isolate. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.

Flow due to multiple jets downstream of a barrage: Experiments, 3-D CFD and depth-averaged modelling

The flow through and downstream of a row of seven open draft tubes in a barrage has been investigated through laboratory experiments in a wide flume, a three-dimensional (3D) computational fluid dynamics simulation, and a two-dimensional depth-averaged computation. Agreement between the experiments and the 3D modeling is shown to be good, including the prediction of an asymmetric Coandă effect. One aim is to determine the distance downstream at which depth-averaged modeling provides a reasonable prediction; this is shown to be approximately 20 tube diameters downstream of the barrage. Upstream of this, the depth-averaged modeling inaccurately predicts water level, bed shear, and the 3D flow field. The 3D model shows that bed shear stress can be markedly magnified near the barrage, particularly where the jets become attached.

Investigating the promotional effect of methanol on the low temperature SCR reaction on Ag/Al2O3

Methanol has been shown to promote the hydrocarbon selective catalytic reduction of NO with octane and toluene over 2wt% Ag/AlO catalyst for the first time. In order to understand its role in the reaction fast transient kinetic methods and in situ DRIFTS analysis have been used. The catalytic activity tests showed that the addition of methanol to the HC-SCR reaction results in a significant improvement in the low temperature activity of a Ag/AlO catalyst, despite the fact that methanol on its own is not reactive for the HC-SCR reaction. This promotional effect of methanol is dependent on the concentration of added methanol and is not necessarily associated with a higher concentration of reductant in the SCR feed. The fast transient kinetic analysis has shown that at each temperature the addition of methanol enhances the conversions of both NO and octane and the production of N with high selectivity in comparison with those observed with n-octane or toluene alone. This phenomenon is similar to the effect of H which may be associated with the release of hydrogen and ammonia during the transient switches at 250 and 300°C. Together with the fast transient experiments, the DRIFTS results showed that NCO species are formed when introducing methanol to the n-octane-SCR feed while CN species are removed/consumed from the surfaces of the Ag catalyst. These NCO species formed by adding methanol may play a vital role in promoting the catalytic activity of NO reduction and methanol itself can be an in situ source for hydrogen formation, which subsequently enhances the SCR reaction. © 2014 Elsevier B.V.

Experimental design and batch experiments for optimization of Cr(VI) removal from aqueous solutions by hydrous cerium oxide nanoparticles

Hydrous cerium oxide (HCO) was synthesized by intercalation of solutions of cerium(III) nitrate and sodium hydroxide and evaluated as an adsorbent for the removal of hexavalent chromium from aqueous solutions. Simple batch experiments and a 2⁵ factorial experimental design were employed to screen the variables affecting Cr(VI) removal efficiency. The effects of the process variables; solution pH, initial Cr(VI) concentration, temperature, adsorbent dose and ionic strength were examined. Using the experimental results, a linear mathematical model representing the influence of the different variables and their interactions was obtained. Analysis of variance (ANOVA) demonstrated that Cr(VI) adsorption significantly increases with decreased solution pH, initial concentration and amount of adsorbent used (dose), but slightly decreased with an increase in temperature and ionic strength. The optimization study indicates 99% as the maximum removal at pH 2, 20 °C, 1.923 mM of metal concentration and a sorbent dose of 4 g/dm³. At these optimal conditions, Langmuir, Freundlich and Redlich–Peterson isotherm models were obtained. The maximum adsorption capacity of Cr(VI) adsorbed by HCO was 0.828 mmol/g, calculated by the Langmuir isotherm model. Desorption of chromium indicated that the HCO adsorbent can be regenerated using NaOH solution 0.1 M (up to 85%). The adsorption interactions between the surface sites of HCO and the Cr(VI) ions were found to be a combined effect of both anion exchange and surface complexation with the formation of an inner-sphere complex.

Effect of feed space allowance and period of access to food on dairy cow performance

Two experiments were conducted to examine the ‘long-term’ effect of feed space allowance and period of access to feed on dairy cow performance. In Experiment 1, three horizontal feed space allowances (20, 40 and 60 cm cow−1) were examined over a 127-d period (14 cows per treatment). In Experiment 2, 48 dairy cows were used in a continuous design (10-week duration) 2 × 2 factorial design experiment comprising two horizontal feed space allowances (15 and 40 cm cow−1), and two periods of access to feed (unrestricted and restricted). With the former, uneaten feed was removed at 08·00 h, while feeding took place at 09·00 h. With the latter, uneaten feed was removed at 06·00 h, while feeding was delayed until 12·00 h. Mean total dry-matter (DM) intakes were 19·0, 18·7 and 19·3 kg cow−1 d−1 with the 20, 40 and 60 cm cow−1 treatments in Experiment 1, and 18·1 and 18·2 kg cow−1 d−1 with the ‘restricted feeding time’ treatments, and 17·8 and 18·1 kg d−1 with the ‘unrestricted feeding time’ treatments (15 and 40 cm respectively) in Experiment 2. None of milk yield, milk composition, or end-of-study live weight or condition score were significantly affected by treatment in either experiment (P > 0·05), while fat + protein yield was reduced with the 15-cm treatment in Experiment 2 (P < 0·05). When access to feed was restricted by space or time constraints, cows modified their time budgets and increased their rates of intake.

Optimisation of a two-liquid component pre-filled acrylic bone cement system: A design of experiments approach to optimise cement final properties

The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery—acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery.

Investigating Feasibility of Drive-by Bridge Monitoring by Laboratory Experiments

A potentially powerful drive-by bridge inspection approach was proposed to inspect bridge conditions utilizing the vibrations of a test vehicle while it passes over the target bridge. This approach suffers from the effect of roadway surface roughness and two solutions were proposed in previous studies: one is to subtract the responses of two vehicles (time-domain method) before spectral analysis and the other one is to subtract the spectrum of one vehicle from that of the other (frequency-domain method). Although the two methods were verified theoretically and numerically, their practical effectiveness is still an open question.Furthermore, whether the outcome spectra processed by those methods could be used to detect potential bridge damage is of our interests. In this study, a laboratory experiment was carried out with a test tractor-trailer system and a scaled bridge. It was observed that, first, for practical applications, it would be preferable to apply the frequency-domain method, avoiding the need to meet a strict requirement in synchronizing the responses of the two trailers in time domain; second, the statistical pattern of the processed spectra in a specific frequency band could be an effective anomaly indicator incorporated in drive-by inspection methods.