Modeling of Asphalt Aging Based on Short-Term Aging Temperature and Time of Normal Asphalt Mixture for Quantifying Binder Aging

The binder in hot-mix asphalt (HMA) is aged (oxidized) in a short-time period during haul-and-queue in the field. Since the oxidative aging of asphalt is a complex chemical process, it is difficult to define the asphalt aging as a function of limited variables. When comparing the same types of asphalt mixes, however, the mix temperature (T) and time (t) kept at the T will be the primary source of variation affecting aging levels of the binder in the mix. Since the binder aging level is not easy to estimate without measuring a physical property, this study concentrated on developing an aging quantity (AQ) model for estimating aging levels of the binder in the mix based on T and t. The loose asphalt mixes were artificially short-term aged at various Ts for different t; 130, 160, and 180 °C for 1, 2, 4, and 8 h. The absolute viscosity (AV) values, which represent aging levels of the recovered binder after each short-term aging (SA) of normal dense-graded mix, were used for regression with AQ values computed by the AQ model. The best-fit AQ model was selected by trial-and-error regression iterations between measured AV and computed AQ. The AQ was then used to estimate AV (EAV) of the aged asphalts in various normal asphalt mixes. It was found that the AQ was useful for estimating AV of the binder in the SA-treated mix, and the EAV by AQ showed an excellent correlation with the measured AV with R2 > 0.99. Therefore, it was possible to conclude that the AQ could be used to predict aging level of various short-term-aged normal asphalt mixes if the materials sources were limited.

Sintesis dan Karakterisasi Carbon Nanotube (CNt) dari Arang Kayu Jati serta Pemanfaatannya Sebagai Bahan Aktif Antibakteri

Carbone Nanotube (CNt) was one of antibacterial compound synthesized from carbon pr activated carbon. In this study threated the synthesis of CNt from teak charcoal used strong acid and sonication. The rendement of CNt synthesis showed potential result 37,6555±0,8038%. The characterization to the CNt showed density 1,0145±0,0037g/cc; Absolute Viscosity 1,06±0,0245P.a; Molecule weight 0,0007±0,00002g/mol. Threated the metal ionic doped to the CNt solution used Ag, Cu, Fe(II), Fe(III). Mg and Zn to increase the stabilitation and interaction. The characterization of CNt-Ag showed density 1,0072±0,0055g/cc; Absolute Viscosity 0,66±0,0400P.a; Molecule weight 0,0007±0,00004g/mol. The characterization of CNt-Cu showed density 1,0086±0,0040g/cc; Absolute Viscosity 0,56±0,0400P.a; Molecule weight 0,0007±0,00003g/mol. The characterization of CNt-Fe(II) showed density 1,0060±0,0013g/cc; Absolute Viscosity 0,76±0,0400P.a; Molecule weight 0,0007±0,000001g/mol. The characterization of CNt-Fe(III) showed density 1,0159±0,0042g/cc; Absolyte Viscosity 0,82±0,0200P.a; Molecule weight 0,0007±0,00003g/mol. Characterization of CNt-Mg showed density 0,9970±0,0008g/cc; Absolute Viscosity 0,64±0,0400P.a; Molecule weight 0,0007±0,000005g/mol. Characterization of CNt-Zn showed density 1,0013±0,0013g/cc; Absolute Viscosity 0,60±0,0447P.a; Molecule weight 0,0007±0,000005g/mol. Threated the mix to the CNt by another antibacterial compounds like Hydroxyapatite (HAp), Chitosan and Nano Chitosan. From the characterization of CNt-HAp obtained density 1,0008±0,0010g/cc; Absolute Viscosity 0,60±0,0316P.a; Molecule weight 0,0007±0,000007g/mol. Characterization CNt-Chitosan obtained density 0,9992±0,0019g/cc; Absolute Viscosity 0,42±0,0200P.a; Molecule weight 0,4343±0,0207g/mol. Characterization CNt-Nano Chitosan obtained density 1,0084±0,0002g/cc; Absolute Viscosity 0,50±0,0316P.a; Molecule weight 0,5170±0,3270g/mol. The results of antibacterial activity measurements against E.coli bacteries showed that all of the threatment to the chars produced the antibacterial activity in middle to strong range.

Rheological Properties of Aqueous Dispersions of Bacterial Cellulose

Bacterial cellulose as polysaccharide possessing outstanding chemical purity and a unique structure compared with wood cellulose, attracts great attention as a hydrocolloid system. It was shown, that at intense mechanical action on a neat bacterial cellulose film in presence of water, the gel-like dispersions are obtained. They retain stability in time (at least, up to several months) and temperature (at least, up to 60 °C) without macro-phase separation on aqueous and cellulose phases. The main indicator of the stability is constant viscosity values in time, as well as fulfilling the Arrhenius dependence for temperature dependence of viscosity. Flow curves of diluted dispersions (BC content less than 1.23%) show strong non-Newtonian behavior over the entire range of shear rates. It is similar with dispersions of micro- and nanocrystalline cellulose, but the absolute viscosity value is much higher in the case of BC due to more long fibrils forming more dense entanglements network than in other cases. Measuring the viscosity in increase and decrease shear rate modes indicate an existence of hysteresis loop, i.e., thixotropic behavior with time lag for recovering the structural network. MCC and NCC dispersions even at cellulose content more than 5% do not demonstrate such behavior. According to oscillatory measurements, viscoelastic behavior of dispersions corresponds to gel-like systems with almost total independence of moduli on frequency and essentially higher values of the storage modulus compared with the loss modulus.

Evaluation of gum arabic from Acacia senegal var kerensis and Acacia senegal var senegal as a stabilizer in low-fat yoghurt

Gum arabic is a dried, gummy exudate obtained from the stems and branches of Acacia senegal and Acacia seyal. In Kenya, gum arabic comes from Acacia senegal var kerensis although its exploitation for commercial and industrial application is marginal. Therefore, the aim of this study was to characterize and determine the effect of the gum from A. senegal var kerensis on the quality characteristics of set low-fat yoghurt compared to gum arabic from A. senegal var senegal, with a view to increasing its utilization locally. Yoghurt was prepared containing gum arabic at four concentrations (0.2%, 0.4%, 0.6%, 0.8% gum w/v). Results showed that A. senegal var kerensis gum had higher molecular weight and gelling properties compared to A. senegal var senegal gum. In addition, A. senegal var kerensis gum was less susceptible to syneresis and showed a higher absolute viscosity compared to A. senegal var senegal gum at all concentration levels. Sensory evaluation revealed that addition of gum arabic significantly improved the body and the texture of the yoghurt. Therefore, A. senegal var kerensis gum is a better yoghurt stabilizer than gum arabic from A. senegal var senegal. An optimal gum concentration of 0.6% of A. senegal var kerensis gum in low-fat yoghurt is recommended from the results of this study.

Fatty acid profile and physicochemical characterization of buriti oil during storage

ABSTRACT: The objective of this research was to evaluate the fatty acid profile and physicochemical properties of buriti oil under storage conditions. The oil was analyzed for 70 days by evaluating the physicochemical characteristics of acidity index, refractive index, bulk density, absolute viscosity, peroxide index, lipid oxidation by TBARS method, color parameters (L *, a *, b *, C * e h *) and carotenoid profile (α-carotene and β-carotene) for every 10 days of storage, in addition to the β-carotene/linoleic acid system and fatty acid profile. Variables remained stable over the analysis periods and the total carotenoids ranged from 836.91 to 1036.96 µg/g. Oleic acid accounted for the highest content among fatty acids, with a value of 78.06 g/100 g of fatty acids and a ω6/ω3 ratio of 1.95. Buriti oil has a nutritional quality and a fatty acid profile that justifies recommendations for its consumption, suggesting the need for regulatory bodies to draw up a standardized protocol for extracting oil from the fruit pulp.

Utilization of ATR-FTIR Spectroscopy-Multivariate Chemometric Analysis in the Examine of Food Quality Edible Sesame Oils

Attenuated total reflectance (ATR)-Fourier transform infrared spectroscopy (FTIR) and multivariate chemometric analysis was established to distinguish and classify edible sesame oils of various branded (refined) and unbranded (cold pressed) oils and principal components. For this determination, available branded and unbranded traditional cold pressed sesame oils from southern districts of Tamilnadu, India were qualitative and quantitatively analyzed and authenticated. The FTIR spectra were generated in absorption ranges from 599- 4000 cm-1 observed through ATR mode. The generated spectral data combined with multivariate chemometric analyses such as Principal components analysis (PCA), Principal coordinate analysis (PCoA), Agglomerative hierarchical clustering analysis (AHC), Discriminant analysis (DA) were analyzed. Further, observed qualitative analyses through colour, UV-light absorption, absolute viscosity, saponification and iodine values were well differentiated between branded and unbranded sesame oil samples. Based on the multivariate chemometric analysis, unbranded 2 and branded 1 sesame oil samples have shown essential phytocomponents like sesamin, sesaminol, and sesamolin. However, other oil samples did not show those essential phytocomponents and may be missing/eliminated during the refining/filtration processes. In addition, branded and unbranded sesame oil samples have been classified through discriminant analysis (DA) based on the major absorption frequencies. As per the experimental and statistical outcomes, it might be established that ATR-FTIR method has potential to detect and identify essential components of similar food products for classification and authentication, further; it is nondestructive, effective and simple alternative method.

Viscosity and Density of 1-Alkanol (C3–C11) Quaternary and Quinary Systems at Different Temperature Levels.

The measured kinematic viscosity and density and the calculated absolute viscosity for selected quaternary and quinary n-alkanol mixtures are presented in this study. The mixtures are composed of 1-propanol, 1-pentanol, 1- heptanol, 1-nonanol, and 1-undecanol. Both the kinematic viscosity and density were measured for the pure components and several intermediate compositions for the selected mixtures at two temperature levels of 293.15 and 298.15 K. The measured data were used to test the predictive capability of different models. The McAllister three body interaction model and the GC-UNIMOD model showed the best overall predictive capability of all models.

A novel technique for mapping viscosity in discrete subcellular locations with a BODIPY based fluorescent probe

Numerous cellular processes, including enzyme behaviour, signalling, and protein folding and transport are highly influenced by the local microviscosity environment within living cells. Molecular rotors are fluorescent molecules that respond to the viscosity of their environment through changes in both the intensity and lifetime of their fluorescence. We have synthesised a novel boron-dipyrrin (BODIPY) molecular rotor that is also a substrate for the SNAP-tag targeting system (named BG-BODIPY), allowing us to target the rotor to discrete locations within the living cell. We demonstrate that BG-BODIPY reports viscosity, and that this can be measured either through fluorescence lifetime or intensity ratiometric measurements. The relative microviscosities within the ER, Golgi, mitochondrial matrix, peroxisomes, lysosomes, cytoplasm, and nucleoplasm were significantly different. Additionally, this approach permitted fluorescence lifetime imaging microscopy (FLIM) to determine the absolute viscosity within both mitochondria and stress granules, showcasing BG-BODIPY’s usefulness in studying both membrane bound and membraneless organelles. These results highlight targeted BG-BODIPY’s broad usefulness for making measurements of cellular viscosity both with FLIM and conventional confocal microscopy, the latter option greatly extending the accessibility of the technique.