Kinetic Study of the Thermal Dehydration of Fly Ash Filled Geopolymers

Metakaolin-based geopolymers at different percentage of fly ash (namely 25, 50, and 70% wt) are prepared by using recycled fly ash, aiming at reducing the amount of waste to be treated or disposed in landfills. The synthesized samples are subjected to the thermogravimetric analysis (TGA) to investigate the kinetics of dehydration process. To this purpose, TGA data are treated by the Kissinger method to calculate the apparent activation energy (Ea) of dehydration. The obtained kinetics parameters are discussed and compared with each other and with those obtained for the control geopolymer. A decrease in Ea values of the filled geopolymers is found, showing the effect of the fly ash in reducing the dehydration rate. A classification among the samples at different percentage of fly ash is also drawn up, showing the reaching of a plateau at percentage above the 50 wt%

Biocatalysis for biomass valorization: peptides and fatty acids from rice bran

Waste upgrading practises have attracted a significant attention in recent years with the aim of managing agrofood by-products in a gainful and sustainable way. We describe here how biocatalysis can assist rice bran valorization, according to the biorefinery concept. [1] Rice is the staple food for over half the world's population. Rice milling generates a massive amount of waste, namely rice bran (70 kg/ton of rice) and rice husk (200 kg/ton of rice). Rice bran (RB), containing fibers (7-11%), proteins (10-16%), lipids (15-22%), carbohydrates (34-52%), micronutrients, represents a second-generation biomass. [2] Rice bran proteins (RBP) have a high nutritional value and optimal digestibility and are gluten-free, hypoallergenic and rich in essential amino acids. However, the first hurdle to be overcome for RBP production and large scale application is their extraction. Structural complexity, poor solubility, and strong aggregation make RBP hardly available. The sequential treatment of RB with carbohydrases and proteases was used to prepare mixtures of water-soluble peptides (RBPHs, RBP Hydrolysates) to be tested as antibacterial, antioxidant and anticholesterol agents, as well as flavour enhancers. [3] Interestingly, sensory analysis revealed that the obtained RBPHs exert only sweet and umami taste. Rice bran oil (RBO) is one of the most underutilized agricultural commodities. We investigated the use of RBO as a feedstock for the production of FFA-derived chemicals (e.g. sugar fatty acid esters). [4] To this aim, RBO was submitted to a preparative lipase-catalyzed hydrolysis to obtain pure FFA. [5] The high acidity of RBO, so far considered as a bottleneck in the exploitation of RBO (i.e. biodiesel production) was here turned into an advantage, making available FFA mixtures as synthetic precursors for high added value products

Calf health from birth to weaning. II. Management of diarrhoea in pre-weaned calves

Calfhood diseases have a major impact on the economic viability of cattle operations. The second of this three part review series considers the management of diarrhoeic diseases in pre-weaned calves. In neonatal calf diarrhoea, oral rehydration therapy is the single most important therapeutic measure to be carried out by the farmer and is usually successful if instigated immediately after diarrhoea has developed. Continued feeding of milk or milk replacer to diarrhoeic calves is important, to prevent malnourishment and weight loss in affected calves. Indiscriminative antibiotic treatment of uncomplicated diarrhoea is discouraged, whereas systemically ill calves can benefit from systemic antibiotic treatment for the prevention of septicaemia or concurrent diseases. Ancillary treatments and specific preventive measures are discussed. Eimeriosis has a high economic impact on the farming industries due to direct cost of treatment and calf losses, but especially due to decreased performance of clinically as well as sub-clinically affected animals. Emphasis lies on prophylactic or metaphylactic treatment, since the degree of damage to the intestinal mucosa once diarrhoea has developed, makes therapeutic intervention unrewarding

15N NMR Spectroscopy of Annulated \u3942- Pyrazolines and \u3942-1,2,4-Triazolines

Enantiopure \u3942-pyrazolines and \u3942-1,2,4-triazolines fused to the 1,4-benzodiazepine moiety, as well as \u3942-pyrazolines annulated to the 1,5-benzoxazocine moiety (racemic) or inserted in a bis-1,3-pyrazolophane skeleton (enantiopure) were investigated through 15N NMR spectroscopy in natural abundance. Nitrogen chemical shifts were determined by (1D)-INEPT experiments, while proton-nitrogen scalar coupling were obtained through 2D-J-HMBC experiments

Epoxy/thermoplastic blends: the effects of two different aromatic modifiers

In this article, a study of the properties of selected epoxy/thermoplastic blends based on the addition of two different types of aromatic modifiers is presented. The epoxy monomer used was a diglycidyl ether of biphenol A cured by 4,4′methylene bis(2,6-diethylaniline) as an amine-curing agent. One modifier was a commercial poly(2,6-dimethyl-1,4-phenylene ether or oxide) (PPE or PPO), while the other was a random copolyethersulphone synthesized in our laboratory. Several different percentages of modifiers varying from 5 to 30 wt% were considered in order to evaluate a wide spectrum of morphologies. The blends have been thoroughly characterized by parallel plate rheometry, dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM). The isothermal rheology revealed some peculiar features for the blends modified by the addition of PPO as modifier. PPO bimodal mass distribution induced a two-phase separation transitions that were not observed with blends containing copolyethersulphone. All the blends presented phase-separated morphology that was clearly observed by SEM analysis. DMTA supported the results of SEM and rheology showing multi-peak behaviour in the loss tangent curves that are typical of phase-separated systems. </jats:p

15N NMR spectroscopy of partially unsaturated pyrazoles

Partially saturated pyrazoles, namely 1-(4-substituted)phenyl-3-methoxycarbonyl-5-ethoxycarbonyl-4,5-dihydropyrazoles, were submitted to extensive 15N NMR spectroscopic analyses, performed in natural abundance. Nitrogen chemical shifts were measured by means of INEPT and HMBC experiments, while long range proton\u2013nitrogen scalar coupling values were taken through J-HMBC experiments. A linear plot between nitrogen chemical shifts and Hammett \u3c3p was observed, enabling us to relate quantitatively the observed chemical shifts to the electronic features of the substituent in the 1-position of the 4,5-dihydropyrazole ring

Esca studies on the structure of amorphous addition complexes of tin dichloride with aromatic schiff bases

The ESCA characterization of three similar new amorphous addition complexes of tin dichloride with tetradentate aromatic Schiff bases has been carried out. The results support the previously proposed ionic structure. © 1983