Studies of the effect of molding pressure and incorporation of sugarcane bagasse fibers on the structure and properties of poly (hydroxy butyrate)

Poly (hydroxy butyrate) (PHB) is a biodegradable polymer that can be obtained from both renewable and synthetic resources. There have been many attempts to improve its structure and properties by different methods. This paper, while mentioning briefly PHB and sugarcane bagasse fibers, focuses on the effect of compressive/molding pressure on its structure and thermal properties with incorporation of sugarcane bagasse fibers, with and without steam explosion treatment. Thermal behavior (thermogravimetry and dynamic mechanical analysis), X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy methods were used to understand the changes in PHB resulting from the pressure and incorporation of fibers while scanning electron microscopy is used to understand the morphology of both the fiber and PHB.     

Isolation and Characterization of Starch from Seeds of Araucaria brasiliensis: A Novel Starch for Application in Food Industry

The pinhão seeds (Araucaria angustifolia), are composed of 34% of starch and very low fractions of protein, lipids and phenolic compounds. This composition is favorable to obtain a stable, white in color and odorless starch, useful in the food industry. The isolated starch is constituted predominantly of small‐sized round granules (10–25 μm), rather than oval ones. Compared to corn starch, pinhão starch has a lower temperature and enthalpy of gelatinization. Retrogradation occurs to a lower extent in pinhão starch, due to its lower amylose content (∼25%). The pasting profile of pinhão starch showed a higher consistency than that of corn starch, with lower temperature in the peak of maximum viscosity. The higher swelling and solubility values of pinhão starch, in conjunction with the higher storage modulus (G') suggest new different applications of this novel starch. The low protein content of the starch granule favors applications like production of glucose and fructose syrups. The simple method of extraction and the high yield of starch from pinhão seed might be attractive not only for pilot‐plant but also for commercial‐scale production.     

Mass Transfer During Vanilla Pods Solid Liquid Extraction: Effect of Extraction Method

In this paper, experimental kinetics of vanilla pods’ solid–liquid extraction were obtained by three different methods: with agitation, without agitation, and microwave-assisted (MAE) without agitation. The extraction kinetics of aroma compounds (vanillin, p-hydroxybenzaldehyde, and p-hydroxybenzoic acid) was measured in vanilla pods (refined) and extracts by high-performance liquid chromatography. Additionally, the equilibrium distribution of aroma compounds between phases and the retained solution by refined pods were experimentally evaluated. A mechanistic model of two simultaneous algebraic equations was fitted to experimental data in order to estimate the aroma compound diffusivities inside the pods and mass transfer coefficients in the extract. The diffusivities in vanilla pods at 50 °C were 4.31?×?10^?11, 2.93?×?10^?11, and 3.50?×?10^?11?m²?s^?1 for vanillin, p-hydroxybenzaldehyde, and p-hydroxybenzoic acid, respectively. External mass transfer coefficients were in the order of 1.0?×?10^?4?m?s^?1 for forced convection extraction and MAE and 3.33?×?10^?7?m?s^?1 for natural convection extraction.     

Limnology and pollution of a small, shallow tropical water-body (jagüey) in North-East Mexico

The environmental characteristics and degree of pollution of a jagüey (a small, shallow tropical water‐body) in Mexico were identified by means of an environmental impact matrix. Jagüeys are important as their main sources of water are the subsurface water‐table and rainfall, however, they have not been studied because of their small size. A flow diagram was designed to incorporate the main climatic, geological and hydrological environmental factors, as well as physico‐chemical data on sediment and water qualities, and biological, technostructural and socioeconomic aspects. The resulting index of –90 in the environmental impact matrix indicates a severe negative impact on jagüeys from the input of allochtonous nutrients because of their small depth, limited circulation and the high rate of evaporation. The jagüeys studied appear in a state of hypertrophy and senility, despite geological youth.     

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

Melting gels are hybrid gels that have the ability to soften and flow at around 100°C for some combinations of mono‐ and di‐substituted alkoxysiloxanes, where substitutions are either all aromatic or all aliphatic. In this study, melting gels were prepared using phenyltriethoxysilane (PhTES) and dimethyldiethoxysilane (DMDES), meaning both an aromatic and aliphatic substitution. Differential scanning calorimetry was performed to identify glass‐transition temperatures, and thermal gravimetric analysis coupled with differential thermal analysis (TGA‐DTA) was performed to measure weight loss. The glass‐transition temperatures (T_g) ranged from ?61°C to +5.6°C, which are between the values in the methyl only system, where all T_g values are less than 0°C, and those values in the phenyl only system, where T_g values are greater than 0°C. The T_g decreased with an increase in the DMDES fraction. Below 450°C, the gels lost little weight, but around 600°C there was a drop in weight. This temperature is lower than the temperature for gels prepared with only aromatic substitutions, but higher than that for gels prepared with only aliphatic substitutions. Final heat treatment was carried out at 150°C for the gel with 80%PhTES‐20%DMDES (in mol%), and the consolidation temperature increased with increasing DMDES content to 205°C for the gel with 50%PhTES‐50%DMDES. After this heat treatment, the melting gels no longer soften.     

Paving the way to collaborative context-aware mobile applications: a case study on preventing worsening of allergy symptoms

Multimedia Tools and Applications - In recent years, the evolution of smartphones and their software applications has grown exponentially; together with the advance of the Internet of Things and...     

Advances in the knowledge of the double perovskites derived from the conformation and substitution of the material Sr2MgMoO6-δ as anode with potential application in SOFC cell

Regardless of the manufacturing process such as solid-state reaction, sol-gel, etc., applied in obtaining anodes in solid oxide fuel cells (SOFCs), Sr₂MgMoO_6-δ (SMMO) double perovskites are recognized worldwide and widely used as anodic material with potential application in SOFC. This is due to several factors such as high electronic conductivity, high electrocatalytic activity, structural stability under reducing atmosphere, high transition temperature, giant magnetoresistance, reasonable tolerance to carbon formation, and its desired ability to reduce sulfur poisoning. In this review article, the advances of the SMMO double perovskite are analyzed.