Physico chemical Properties

Chitosan films obtained by dry phase inversion were prepared from an aqueous solution of chitosan in acetic acid. The films, of thickness less than 20 μm, were transparent, very flexible and had smooth surfaces. Increasing the film thickness induced an increase of the internal tensions and the consequent formation of a rough surface. Structural investigations by X-ray diffraction and Fourier transform IR analysis, showed that the chitosan films, as prepared, are amorphous. Further annealing to evaporate acetic acid and water traces, changed the amorphous phase into a more ordered phase, characterized by diffraction peaks at 2θ values of 9, 17, 20 and 23 degrees. Thermal investigations by TG, DTG, and DTA revealed that the decomposition of the chitosan films as prepared proceeds in two stages, starting from 180°C and 540°C.

Siliceous, aluminosilicate and niobosilicate mesoporous molecular sieves of MCM-41 type have been used as matrices for nickel incorporated via the wet impregnation. The N 2 adsorption, XRD, H 2 -TPR and Ni dispersion study were applied for the characterization of the ...

An interesting aspect of nanotechnology is the remarkable size-dependent physico-chemical properties of nanomaterials that have led to the rise of synthesis procedures for nanomaterials across a range of sizes, shapes, and chemical compositions. This chapter will concentrate on the different methods such as electron irradiation, laser ablation, and chemical reduction, biological methods, photochemical methods; microwave processing, chemical vapour condensation (CVC), arc discharge, hydrogen plasma-metal reaction, and laser pyrolysis in the vapour phase. This chapter will also include the various characterization techniques for the conformation of nanomaterials such as UV-visible spectroscopy, x-ray diffraction, and electron microscopy (e.g., transmission electron microscopy [TEM], scanning electron microscopy [SEM], and atomic force microscopy [AFM]).

Annona squamosa and Catunaregam nilotica seeds and oils were characterized for their approximate analysis and physico-chemical properties. The oil and protein contents were 26.8, 17.5 and 40.0, 22.2%, in A. squamosa and C. nilotica seeds, respectively. The oils were extracted using cold extraction (CE) and Soxhlet extraction (SE) methods. Fatty acids and tocopherols were determined by GC–MS and HPLC, respectively. Generally the physico-chemical properties and fatty acids were not significantly (P ≤ 0.05) affected by the extraction methods. The major fatty acids of A. squamosa oil extracted by CE and SE were oleic 49.2 and 50.5%, linoleic 22.3 and 22.7%, palmitic 15.6 and 15.2%, and stearic 10.6 and 9.3%, respectively. While the major fatty acids in C. nilotica oil extracted by CE and SE were oleic 10.5, and 10.4%, linoleic 63.1 and 63.4%, palmitic 9.7 and 9.8% and stearic 5.1 and 5.4%, respectively. The tocopherol content of CE and SE extracted oils from A. squamosa amounted to 16.6 and 15.5 and from C. nilotica amounted to 110.5 and 107.7 mg/100 g oil, respectively, with delta-tocopherol as the predominant tocopherol in A. squamosa oil, and beta-tocopherol in C. nilotica oil. The total amount of amino acids was found to be 7.266 and 14.202 g/100 g protein, in seeds of A. squamosa and C. nilotica, respectively.

Revista BISTUA I 91 INTRODUCCIÓN El 17 de febrero de 1869 [1 ], Mendeléiev 2 encontró las relaciones periódicas de los elementos químicos, pero tal vez lo más relevante de su descubrimiento no fueron estas relaciones, o las periodicidades de las propiedades con respecto al peso atómico (hoy al número atómico gracias a los trabajos de RESUMEN El sistema periódico de los elementos químicos visto como un conjunto de objetos definidos por sus propiedades físico-químicas, es susceptible de ser estudiado mediante matemática de conjuntos y topología general. En este trabajo hacemos una revisión de este estudio y resaltamos resultados como que la frontera matemática de los metales es un grupo de elementos semimetálicos y que los elementos alcalinos y gases nobles son elementos que guardan pocas relaciones de similitud con el resto de los elementos. ABSTRACT The periodic system of chemical elements view as a set of objects, all of them defined by their physico-chemical properties, can be stu...

Physico-chemical and sensory quality of juice from purple passion fruit under different storage temperature and time were assessed. The maximum loss in fruit weight was recorded under room temperature (25 ± 1°C) followed by at 11 ± 1°C. There was an increase in juice percentage up to 9 and 13 days under room temperature and storage at 11 ± 1°C respectively. The optimum flavour in juice was

In this study, local assessment of water quality is used to illustrate key features of aquatic environments, and demonstrate how human activities on the landscape can influence water quality in both positive and negative ways. Poor water quality can be the result of natural processes but more associated with human activities and is closely linked to industrial development. Iligan City is considered a home of majestic waterfalls and other bodies of water. Thus, this study was conducted to assess the water quality of Timoga River (downstream), Buruun, Iligan City in terms of physico-chemical parameters (temperature, water salinity, dissolved oxygen and pH); nutrient analyses (phosphates, nitrates and nitrites) and bacteriological analysis (coliform load) using standard methods. Results of this study yield pH values ranging from 9.11 to 9.72 hence, indicating poor water quality for all the sampling stations since, based on EPA standard (2007) pH values between 6.5 and 8.5 are the pH values indicating good water quality. A possibility for the observed high alkalinity of water in the area is the presence of man-made laundry well near the river used by community residents for washing clothes, washing dishes and for cleaning purposes. The water coming from the well containing soaps, detergents and " bleach, " Sodium Hypochlorite (NaOCl) flows directly to the river system and the rise of water level may cover the well especially during high tide. Alkaline compounds as discharges from industries are also great contributors to water alkalinity (increase in pH). Moreover, based on the EPA guidelines for healthy surface, waters dissolved oxygen concentration-DO (mg/L) should be at least 8, here sampling stations yield values below the standard. In terms of nutrient analyses, nitrate concentrations were relatively high compared to the standard of no more than 0.38 mg/L, while the nitrite concentration is relatively low. Phosphate concentrations for all stations were also fairly higher than 10.0µg/L. In terms of bacteriological analyses, the bacteria present were Escherichia coli and Enterobacter sp. With this information, appropriate actions should be disseminated in order to address the need in taking care of these water resources which is vital to environment and human health.