Chemometric Comparison of Data Files Using Several Thermal Analytical Techniques for Dating Fossil Bones from Two Old Burial Sites.

Background:: The possibility of estimating the age of fossil bones using only classic thermogravimetry, on the basis of proper % mass loss ratio values, has been widely considered in the past years. Objective:: Our research has brought some innovations to the previous background, by using chemometric methods and by processing the numerical files of whole thermogravimetric curves. The objective of this paper is the selection, among the main thermal analysis methods available, i.e. thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA) and thermal dilatometry analysis (TDA), of the most suitable one, in order to evaluate the age of fossil bones. Methods:: Fossil bone samples from two ancient cemeteries in Sudan were analyzed using different thermal methods (TG, DTG, DTA and TDA). Data of whole recorded thermal curves have been processed by PCA analysis. Results:: A systematic comparison of several thermal analytical techniques allowed to conclude that TG or DTG curves can provide more appropriate information to determine how old fossil bones of different ages are, as evidenced by PCA processing of the entire file set of TG or DTG curves. Conclusion:: It can be concluded that the chemometric processing of TG or DTG curves data files is the best method, however, discussing other thermal analytical curves (DTA and TDA), can complete the information found by means of chemometric processing of whole TG and DTG curves.

Cyclization of Multi Components Reactions and (Preparation, Investigation, Thermal Curves)

Many cyclic compounds were formatted via multi components reactions and cyclization reaction through many steps with ( various conditions , various starting materials , various components ), in first step , aromatic amine derivative were reacted with ammonium thiocyanate in cyclization reaction to yield 2-aminobenzothiazole derivative , which reacted with formaldehyde and benzaldehyde as a multi components reaction ., then the resulting compounds cyclized with ( semicarbazide , ortho-phenyl diamine , ortho-thiol aniline , ortho- amino phenol ). Investigation of compounds carried out through many techniques ( FT.IR , H.NMR , Mass ) – Spectra , Thermal studies

Thermal Behavior and Spectroscopy Analysis of Carbonized Nanostructures Derived from Polypyrrole Nanotubes

Carbonaceous nanotubes with a calculated specific heat of 710[Formula: see text]J K[Formula: see text] Kg[Formula: see text], and an outer diameter of 58[Formula: see text]nm, made by a micro-thermal reaction, using polypyrrole nanotubes precursor is presented here. Three degradation stages from the thermal curves are identified. We observe a decomposition temperature at 371[Formula: see text]C that relates to the presence of amorphous carbon on samples for the first time in this material. Also, it is identified that gradual decomposition of the fragments provides a different kind of residue percentage in the range 48–32% that is related to stirring speed used in each synthesis. It is worthy to note that electron transmission microscope images of carbonaceous nanotubes present defects as well, wherein we identify chloride and nitrogen as doped agents. Finally, results of nanotubes using Infrared, Raman spectrometry analysis, scanning electron microscopy and electron diffraction are presented here.

Quantitative Study of Thermal Disturbances Due to Nonuniformly Perfused Tumors in Peripheral Regions of Women’s Breast

Background: Mathematical modeling of biothermal processes is widely used to enhance the quantitative understanding of thermoregulation system of human body organs. This quantitative knowledge of thermal information of various human body organs can be used for developing clinical applications. In the past, investigators have studied thermal distribution in hemisphere-shaped human breast in the presence of sphere-shaped tumor. The shape and size of the breast as well as tumor may also affect thermal distribution which can have serious implications in thermography. In this article, a model of thermal disturbances in peripheral regions of ellipsoid-shaped human breast involving ellipse-shaped nonuniformly perfused tumor has been developed for a 2-dimensional steady-state case. The modeling study will provide biomedical scientists vital insights of thermal changes occurring due to the shape and size of breast and tumor which can influence the development of protocols of thermography for diagnosis of tumors in women’s breast. Method: We have incorporated the significant parameters such as blood flow, metabolic activity, and thermal conductivity in the thermal model for normal and malignant tissues. The controlled metabolic activity has been incorporated for normal tissues, and uncontrolled metabolic activity has been incorporated for tumor regions. The peripheral regions of breast are divided into 3 major layers, namely, epidermis, dermis, and subdermal tissues. An ellipse-shaped nonuniformly perfused tumor is assumed to be present in dermal layers. The nonuniformly perfused tumor is divided into 2 natural components, namely, the necrotic core and tumor periphery. The outer surface of the breast is assumed to be exposed to the environment, and the heat loss takes place by conduction, convection, radiation, and evaporation. The finite element approach is used to obtain the solution. The numerical results have been used to study the effect of shape and size of tumor on temperature distribution in matured breast of different shapes. Results: By selecting appropriate model parameters, we have shown the spatial thermal variation in matured breast of different shapes which could be replicated by the proposed model. We have also shown the thermal disturbances caused by different shapes and sizes of tumors by selecting appropriate values of parameters. In addition, the thermal information from our model provides us the basis for prediction of shape and size of tumors in terms of change of the slope of temperature profiles at the junction of tumor and normal tissues and tumor periphery and tumor core. Conclusions: The proposed model was successfully used to study the impact of different sizes and shapes of nonuniformly perfused tumor on thermograms in peripheral regions of ellipse-shaped woman’s breast. The proposed model is more realistic in terms of shape and size of tumors and woman’s breast in comparison with earlier models reported in the literature. The finite element discretization of breast into large number of triangular ring elements effectively models the heterogeneity of region. The changes in slope of the thermal curves at the junctions of various peripheral and tumor layers are due to the nonhomogeneous nature of the region. The location of major thermal disturbances in the tissues indicates the presence of tumor. The change in the slope of the thermal curves gives us idea about the position, type, and size of the tumors in the peripheral tissues. This thermal information can be exploited for detection of tumors by thermographic techniques.

Influence of Nitrogen Atmosphere Annealing on Structural and Transport Properties of Fe1.125Te

Fe1.125Te alloys had been synthesized by solid state reaction methods. The effects of nitrogen annealing on Fe1.125Te lattice structure and physical properties had been studied. It was found that the lattice constants a and c increased after annealed at temperature 400~600 oC. When the temperature is above 850 oC, the size of the unit cell returns to the similar size of original samples. The step-like magnetic-thermal curves were observed after annealed at 900 oC, which is associated with two magnetic transitions. In vacuum, the transition temperatures are 122 K and 128 K, while in the nitrogen, they are 122 K and 138 K. The resistance-temperature curves indicate a semiconductor to metal transition around 69 K for N2 atmosphere.

A Preliminary Discussion of the Polynomial Fits to the Thermal Curves of Solid-Solid Reactions, Carried Out in Bulk

Dozens of authors have obtained experimental thermal curves of solid-solid reactions, carried out in bulk. Different mathematical functions were used to obtain fits to the thermal curve data. Polynomials were found to give the best fits to the data. The data may be divided into three types on the basis of the shape of the curves, with one peak, with two peaks and with three peaks. In this preliminary report we present one fitted curve of each of the three types as specimen. The importance of the Thermal Curves is briefly pointed out. A detailed discussion of the large amount of the available data may be taken up later.

Evaluation of Crosslinking in Elastomers Using Thermoporometry, Densimetry and Diffential Scanning Calorimetry Analysis

The classical methods available for evaluating the degree of crosslinking in elastomers are stress-strain and swelling measurements. In this study, we have adopted a new analytical approach based on thermoporometry, densimetry and DSC for comparing the crosslinking density in elastomers. Crosslinking by chemical reaction or by photo-oxidation has been studied on polymer samples Ethylene-Propylene-Diene rubber (EPDM) and PolyButadiene (PB). Analysis has been done separately for soluble and insoluble fractions. The soluble fraction has been studied by densimetry and the insoluble fraction by thermoporometry and measurement of decomposition of dicumyl peroxide (DCP). The results of both these studies are complementary to each other. The DSC thermal curves of both EPDM and PB are identical in nature, but the density of the photo-oxidized EPDM samples shows a marked increase contrary to that found in PB.