► Chemical, physical and morphological properties of
R. communis were evaluated by microscopy and image analysis. ► Size and shape descriptors allow characterize endosperm, embryo cells and lipid ...bodies of seeds. ► Numerical data integrate information useful for thermal and mechanical processing of
R. communis seed. ► Microscopy and images analysis were efficient for the characterization of macro and microstructure of seeds and understanding of their relationships properties–structure.
Ricinus communis seed is a source of protein and oil with a high potential to use as animal's feedstock and biodiesel production. However, the oil yield and the extraction efficiency depend on the process conditions applied, as well as on the physical, chemical and structural properties of the seed, which have not been fully investigated. Hence, the objective of this study was to evaluate some chemical and physical properties of
R. communis seed as well as to describe and quantify the macro and microstructure of this raw material by microscopy techniques and image analysis. Chemical analysis confirmed the seeds’ high contents of protein (28.48
±
0.25%) and fat (51
±
0.31%). On the other hand, the values of geometric mean diameter (8.95
±
0.05
mm), bulk density (538
±
11
kg/m
3), and true density (1458
±
27
kg/m
3), among others, were higher than the ones reported about similar oils seeds. Microstructural studies showed that the endosperm cells presented an ovoid shape, as obtained from the aspect ratio results (AR
=
1.28
±
0.17), and a cell density of 570
±
10
cell/mm
2, resulting in a porous structure, while the embryo cells had a cell density of 4903
±
2
cell/mm
2, and an AR of 2.41
±
0.48, related to a more compact structure (rectangular form) in this part of the seed. Regarding to lipids bodies (lb), they were only visible in the endosperm cells, showing a circular shape (AR
=
1.16
±
0.1), and a mean cell density of 9.57
±
2.40
lipid
bodies/μm
2, associated to protein as observed by the mineral presence (K, P, Mg and S) as determined by the energy dispersive X-ray analysis. Microscopy techniques and images analysis were efficient tools for the characterization of macro and microstructure of seeds and the data obtained integrate numerical information that could be useful for thermal and mechanical processing of
R. communis seed, as well as for the design process equipment.
Electrospraying is a technique now applied for the production of food nanoparticles, nanofibres and nanocapsules, which could constitute a good alternative for the development of films. The goal of ...this work was to determine the electrospraying operation conditions and the zein concentration that would allow a film to be produced and also to evaluate the structural characteristics and barrier and thermal properties of films developed at different thicknesses. Results showed that films can be obtained by electrospraying, resulting possible to produce homogeneous films, without electrical arc formation during processing when using a 11.4% zein solution, an electrical voltage of 7.8–8.7 kV and a distance of 1.5 ± 0.5 cm between the nozzle and the deposit plaque. Regarding the effect of the production methods (electrospraying and casting) and the film thickness on film appearance, both variables had significant effect on colour parameters, observing a more yellowish colour (b* = 72.3 ± 6.8) and lower transparency (%T = 90.6 ± 0.21) at larger thicknesses (100 μm), and a smoother and more homogeneous surface (ESEM) when films were obtained by electrospraying. Water vapour permeability was only influenced by film thickness (1.51 × 10−08 to 3.11 × 10−08 g/s-m-Pa) in both methodologies. The glass transition temperatures (Tg) for electrospraying and casting films were different (222 °C and 231 °C respectively) and higher than that of zein powder (165 °C), indicating a possible change in the film structure due to the process. Under the process conditions tested in this work, electrospraying can be considered as an alternative technique to produce films.
Display omitted
•Electrospraying can be used to produce zein films.•Electrospraying generates similar films to those produce by casting.•Electrosprayied zein generates different products as varying process conditions.
Unsupported and y-A12O3-, MCM-41-supported (Ni, Mo) carbides were prepared and modified by `in situ' polymer (PAN: polyacrylonitrile) pyrolysis. The supported catalysts were impregnated with Ni and ...Mo metals, i.e. 2.8 atom Mo/nm2, whose atomic ratio was Ni/Ni + Mo = 0.5. X-ray diffraction (XRD) showed single NiC, MoC phases in all cases, with relatively low surface areas, as verified by N2 adsorption (BET). The catalytic behaviour of the supported (Ni, Mo)C phases for n-C8 hydrocracking depended on the support type. (Ni, Mo)C/MCM41-PAN-P (P = pyrolyzed) showed a total conversion of 40% while it was only 15% on Ni, MoC/y-A12O3. The most active catalysts were (Ni, Mo)C unsupported catalysts, i.e., 90% total conversion. In all cases the hydrocracking selectivity favoured lighter hydrocarbons (C1-C4). The need for clean fuels for improving the quality of air has motivated the development of new catalysts, which must have higher activity and more stringent properties to withstand severe operation conditions.
MCM-41 and FSM-16 were used for enzyme immobilization on account of their good physical and chemical properties. In this work, the catalytic activity of acetylcholinesterase (AChE) immobilized on ...these materials was investigated, using neostigmina as AChE inhibitor. The results show that AChE was adsorbed on MCM-41 and on FSM-16-TIPB. AChE immobilized on the latter material maintained 70% of its activity and the material did not hydrolyze ACh (as MCM-41) by itself. Therefore, FSM-16-TIPB was the best material, considering also that when neostigmine was applied to AChE immobilized on FSM-16-TIPB, the activity of AChE decreased as occurs in its free from. Hence, this model could be useful in the evaluation of different kinds of AChE inhibitors, allowing the recycling of enzymes and making possible several assays and thereby, lowering cost.
The synthesis of Al2O3-composites having different amount of very fine titanium and titanium carbide reinforcement-particles was studied. Two steps were given for the synthesis, the first consisting ...of the pressureless sintering of Al2O3-titanium powders which were thoroughly mixed under high energy ball-milling and the second inducing the formation of TiC over different times at 500 C by the cementation packing process. SEM and EDS analysis of the microstructures obtained in both sintered and cemented bodies were performed to understand the effect of the activated carbon used as the cementing agent on the titanium for each studied composite. It was observed that a TiC layer grew from the surface into the bulk and reached different depths as the titanium content in the composites increased. However, the use of ductile titanium notably enhanced the density level and fracture toughness of the composites.
Castor oil, 2,4-tolylene diisocyanate (2,4 TDI), cellulose acetate, and hydroxiethyl cellulose, based polyurethane (PU) - polyacrylic acid (PAA) sequential interpenetrating polymer networks (IPN's) ...were synthesized. PU's were prepared by reaction of hydroxyl groups from castor oil, and cellulose acetate or hydroxiethyl cellulose with 2,4 TDI, using dibutyl tin dilaurate (DBDTL) as catalyst. PU's were swollen in acrylic acid monomer solution and subsequently polymerized by radical polymerization initiated with 4,4-azobis(4-cyanovaleric acid) (ACVA), and N,N'-methylenebis acrylamide (NNMBA) as crosslinking agent. Series of three PU/PAA ratios (75/25, 50/50, 25/75) were prepared. Viscoelastic properties were studied by means of dynamic mechanical analysis (DMA), showing a maximum modulus for IPN with 25% PAA content. Tan d curve showed two main peaks, and ? relaxation which is due to lateral chains of PU, suggesting phase separation. The existence of two Tg in each IPN was also confirmed by differential scanning calorimeter DSC). Morphology of samples was observed using a scanning electron microscope (SEM), which revealed different fracture surfaces between the compatible and incompatible PU/PAA ratios studied. Fractures were decreasing to turn into roughness surfaces when the PAA was increasing within the IPN's.
In order to determine ways of tailoring Al2O3 in order that one or more toughening mechanisms are activated in service, the production of Al2O3-based composites with different reinforcement metals ...and intermetallics was investigated. The composites were synthesised by means of both liquid and solid pressureless sintering of an intensive mechanical mixture of powders. With the use of various metals in the chemical formulations, significant improvements in ceramic toughness were reported. From fracture toughness measurements and microstructural observations, it could be concluded that the toughening mechanism in Al2O3/metal reinforced composites was due to crack bridging and crack deflection.
A study of NiMo catalysts supported on MCM41 modified with alumina prepared by the sol–gel method is presented. Ni–Mo phases were impregnated on the supports using the solution method with the ...purpose to obtain a material whose hexagonal structure of the MCM41 would not be affected with the addition of these active phases. The impregnation of the metals method used in the present work was outstanding, the textural properties of the catalysts decreased from 42 to 67%. There was a diminution in the textural properties of the catalysts with respect to the supports, nevertheless the prepared materials had more significant textural properties that the conventional catalysts of HDS. The adsorption–desorption isotherms of the catalysts did not change considerably with the support source. By DRX was determined the structural properties of the metallic phases present in the material where phases such as NiMoO
4
, MoO
3
and NiO were observed. Support wall thickness was increased with the incorporation of Ni and Mo metals into the materials. By means of Raman spectroscopy, the presence of MoO
3
and Mo
8
O
26
4−
species was corroborated. Through UV–vis where determined NiO of octahedral symmetry as well as Mo of tetrahedral and octahedral symmetry. The main reaction products were biphenyl (BP), cyclohexylbenzene (CHB) and bicyclohexyl (BCH) when the materials were tested in the HDS of DBT.
The aim of this study was to characterize the growth of the fungus
Leucoagaricus gongylophorus
LEU18496, isolated from the fungus garden of the nest of leaf cutter ants
Atta mexicana.
The fungus ...garden was cultivated in an artificial laboratory nest and the fungus further grown in submerged (SmC) and solid state (SSC) cultures with sugarcane bagasse, grass or model substrates containing CM-cellulose, xylan or lignin. The CO
2
production rate with grass in SmC (Vmax 34.76 mg CO
2
L
gas
−1
day
− 1
) was almost four times than SSC (Vmax 9.49 mg CO
2
L
gas
−1
day
− 1
), while the production rate obtained in sugarcane bagasse in SmC (Vmax 16.02 mg CO
2
L
gas
−1
day
− 1
) was almost three times than that for SSC (Vmax 5.42 mg CO
2
L
gas
−1
day
− 1
). In addition, the fungus grew with defined carbon substrates mixtures in SmC, but at different rates, first xylan, followed by CM-cellulose and lignin. Endoglucanase and xylanase activities (U mg
protein
−1
) were detected in all cultures, the specific activity was higher in the fungus-garden, 5.2 and 1.8; followed by SSC-grass, 1.5 and 0.8, and SSC-bagasse, 0.9 and 0.8, respectively. Laccase activity in the fungus-garden was 44.8 U L
− 1
and 10.9 U L
− 1
in the SSC-grass. The gongylidia structures observed by environmental scanning electron microscopy were ca. 40 µm and the hyphae width ca. 5 µm. The results show that
L. gongylophorus
from
A. mexicana
have promising applications for the treatment of plant residues to release fermentable sugars and the production of high value lignocellulolytic enzymes such as endoglucanase, xylanase or laccases.
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