Pre-treatment technologies,and their effect on international bioenergy supply chain logistics. Techno-economic evaluation of torrefaction,fast pyrolysis and pelletisation

The pre-treatment step has a significant influence on the performance of bioenergy chains, especially on logistics. Torrefaction, pelletisation and pyrolysis technologies can convert biomass at modest scales into dense energy carriers that ease transportation and handling.     

Verleimungsversuche mit Tanninformaldehydharzen aus Rindenextrakten von Pinus brutia Ten.

Tannins from bark of P. brutia are suitable for the preparation of thermosetting adhesives. By using paraformaldehyde or hexamethylenetetramine as hardener boiling water resistant bondings according to DIN 53254 and DIN 68602 could be achieved. Different modifications have been examined. The best results could be obtained with small amounts of a commercial phenolic resin.     

Extraction of sesame seed oil using supercritical CO2 and mathematical modeling

In this work, extraction of sesame oil from sesame seeds using supercritical CO₂ was carried out. The effect of operating parameters such as pressure, temperature, and supercritical CO₂ flow rate and particle size on extraction yield were investigated. An increase in the pressure and the supercritical CO₂ flow rate improved the extraction yield and also shortened the extraction time. The extraction yield increased as the particle size decreased depending on decreasing intraparticle diffusion resistance. The maximum extraction yield obtained was about 85% (relative to Soxhlet extraction by hexane) at 50 °C, 350 bar, 2 mL CO₂/min, 300–600 μm of particle size. Some extraction curves were modeled with two mathematical approaches as shrinking core model and broken and intact core model. The evaluation of model parameters showed that shrinking core model, however, is better than broken and intact cell model.     

Synthesis of chitin calcium phosphate composite in different growth media

This paper presents some results concerning chitin calcium phosphate composites obtained in different growth media. The synthesis of chitin calcium phosphate composite was carried out by phosphorylation, calcification, and soaking in different calcium phosphate growth media. This research is focused on studying and understanding the effect of using different growth media on composite samples. Hydroxyapatite was determined in the composite samples synthesized by using both simulated body fluid (SBF) and calcium phosphorus tris (Ca‐PTris) solution. Calcium/phosphorus (Ca:P) ratio of the composite synthesized by using SBF was found higher than that of composite synthesized by using Ca‐PTris solution as calcium phosphate growth media. The Ca:P ratio of the composite (1.72) immersed in 1.5× SBF for 35 day is similar to the theoretical value of hydroxyapatite (1.67) and closer to the theoretical value of human bone (1.75). POLYM. COMPOS., 29:84–91, 2008. © 2007 Society of Plastics Engineers     

Verwendung der Polyphenole aus der Rinde von Pinus brutia Ten. zur Herstellung von Holzleimen

Hot water extracts of P. brutia bark are eminently suitably for the production of wood adhesives. Up to an extract content of the solution of about 50% the increase of viscosity is only limited. By using paraformaldehyde or hexamethylenetetramine as a curing agent the potlife of adhesive mixtures is sufficient, and without any further modification boil proof bondings can be achieved. Optimum results can be obtained by adding small amounts of a commercial phenolic resin.     

The Effect of Moisture Sorption and Desorption on Furosemide Tablet Properties

The effect of moisture sorption and desorption on the physical characteristics of furosemide tablet was studied at moderately elevated temperatures and different relative humidity conditions over 20 days. The rate of moisture sorption and desorption was founud to follow first order kifietics within first hours. Except ambient conditions (RT/Amb.RH), moisture sorption caused a decrease in hardness values of furosemide tablets. Also the disintegration times of hydrated tablets showed a remarkeable decrease. Changes in hardness and disintegration time were dependent on the amount of water sorbed into the tablets. These significant changes occured during the first days of the test and then became invariant. The variations in hardness and disintegration times of tablets were irreversible as demonstrated by desorption experiments.

Furthermore, except storage at high temperature and high relative humidity dissolution parameters of tablets were less affected by moisture sorption and desorption.     

Equilibrium and kinetic studies for the sorption of 3-methoxybenzaldehyde on activated kaolinites

The sorption of 3-methoxybenzaldehyde on activated kaolinites has been investigated at different temperatures. Two types of activation tests were performed. The sorption equilibrium was studied by sorption isotherms in the temperature range 303-333K for natural (untreated), thermally and acid activated kaolinites. It was shown that the isotherm shapes were not affected by temperature and activation types of kaolinite. The absorbance data at 312nm were fitted reasonably well with the Langmuir and Freundlich isotherm models and the model parameters were determined for different temperatures. Thermodynamic quantities such as Gibbs free energy (DeltaG), the enthalpy (DeltaH) and the entropy change of sorption (DeltaS) were determined for natural, thermally and acid activated kaolinites. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously. Adsorption capacity of acid activated kaolinite for 3-methoxybenzaldehyde was higher compared to that of natural and thermally activated kaolinites at various temperatures. The adsorption and desorption rate constants (k(a) and k(d)) were obtained separately by applying a geometric approach to the first order Langmuir model. This method provided good conformity between the K from Langmuir parameters and K(geo) (k(a)/k(d)) from geometric approach.     

Low cost removal of reactive dyes using wheat bran

In this study, the adsorption of Reactive Blue 19 (RB 19), Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145) onto wheat bran, generated as a by-product material from flour factory, was studied with respect to initial pH, temperature, initial dye concentration, adsorbent concentration and adsorbent size. The adsorption of RB 19, RR 195 and RY 145 onto wheat bran increased with increasing temperature and initial dye concentration while the adsorbed RB 19, RR 195 and RY 145 amounts decreased with increasing initial pH and adsorbent concentration. The Langmuir and Freundlich isotherm models were applied to the experimental equilibrium data depending on temperature and the isotherm constants were determined by using linear regression analysis. The monolayer covarage capacities of wheat bran for RB 19, RR 195 and RY 145 dyes were obtained as 117.6, 119.1 and 196.1 mg/g at 60 degrees C, respectively. It was observed that the reactive dye adsorption capacity of wheat bran decreased in the order of RY 145>RB 19>RR 195. The pseudo-second order kinetic and Weber-Morris models were applied to the experimental data and it was found that both the surface adsorption as well as intraparticle diffusion contributed to the actual adsorption processes of RB 19, RR 195 and RY 145. Regression coefficients (R2) for the pseudo-second order kinetic model were higher than 0.99. Thermodynamic studies showed that the adsorption of RB 19, RR 195 and RY 145 dyes onto wheat bran was endothermic in nature.     

Application of pH control to a tubular flow reactor

Tubular flow reactors are mainly used in chemical industry and waste water discharged units. Control of output variables is very difficult because of the existence of high dead-time in these types of r...     

Particle size design of digitoxin in supercritical fluids

Bioavailability of the pharmaceutical substances is very important for their activity. In case of necessity, bioavailability can be improved by reducing the particle size of the drugs. In this study, particle size of digitoxin was reduced by the Rapid Expansion of Supercritical Solutions (RESS). The effects of pre-expansion temperature (90-110 °C), flow rate (2.5-7.5 ml/min), spray distance (3-7 cm) on the size and size distribution of the precipitated digitoxin particles were carried out. The particles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and LC-MS analysis.While the particle size range of the original digitoxin was 0.2-8 μm, it was decreased to 68-458 nm and determined that 97% of the particles were below 200 nm depending on the different experimental conditions.Response surface method (RSM) was used to optimize the process parameters. The flow rate, 7 ml/min; spray distance, 7 cm; pre-expansion temperature, 95 °C were found to be the optimum conditions to achieve the minimum particle size of digitoxin.