Removing Simultaneously Sulfur and Nitrogen from Fuel under a Sustainable Oxidative Catalytic System

An effective process to remove nitrogen-based compounds from fossil fuels without harming the process of sulfur removal is an actual gap in refineries. A success combination of desulfurization and denitrogenation processes capable of completely removing the most environmental contaminates in diesel under sustainable conditions was achieved in this work, applying polyoxometalates as catalysts, hydrogen peroxide as oxidant, and an immiscible ionic liquid as an extraction solvent. The developed process based in simultaneous oxidative desulfurization (ODS) and oxidative denitrogenation (ODN) involved initial extraction of sulfur and nitrogen compounds followed by catalytic oxidation. Keggin-type polyoxomolybdates revealed much higher reusing capacity than the related polyoxotungstate. Effectively, the first catalysts practically allowed complete sulfur and nitrogen removal only in 1 h of reaction and for ten consecutive cycles, maintaining the original catalyst and ionic liquid samples.

KINETICS AND THERMODYNAMICS OF PEPPERMINT OIL EXTRACTION FROM PEPPERMINT LEAVES

This study aimed to extraction of essential oil from peppermint leaves by using hydro distillation methods. In the peppermint oil extraction with hydro distillation method is studied the effect of the extraction temperature to the yield of peppermint oil. Besides it also studied the kinetics during the extraction process. Then, 2nd -order mechanism was adopted in the model of hydro distillation for estimation many parameters such as the initial extraction rate, capacity of extraction and the constant rat of extraction with various temperature. The same model was also used to estimate the activation energy. The results showed a spontaneous process, since the Gibbs free energy had a value negative sign.

Kinetic Modelling of Solid-Liquid Extraction of Anthocyanins of Gynura Crepioides Leaves

Gynura crepioides is one of the natural resources of flavonoid compounds, including anthocyanins (ACs) that provide a lot of nutritional values to human and use as a natural colourant. For efficient extraction, optimization and kinetic data is very essential. In this investigation, optimization and kinetic modelling focusing on temperature effect on solid-liquid extraction of freeze-dried anthocyanins leaves of Gynura crepioides was performed. Freeze drying material was used in extraction to ensure high recovery of useful bioactive compounds in subsequent process. It was found that the rate of extraction was very fast at the beginning, but it began to slow down until it remained constant and reached the plateau after 45 minutes for all temperatures. As temperature increases, the initial extraction rate (h) and extraction rate constant (k) values also increased. The highest initial extraction rate and extraction rate constant were calculated to be 16.64 mg L-1 min-1 and 17.8 x 10-3 L mg-1 min-1 at 333K.However, after 60 minutes of extraction time, degradation of anthocyanins can be seen at 333K and thus reduce the yield. Higher temperature is known to reduce the quantity and quality of bioactive compound. Hence temperature of lower than 333K is desirable for industrial application. The kinetics of extraction data were corresponding well to second-order reaction. The activation energy is calculated as 18.45 kJ mol-1, which is an indication of an endothermic process. An empirical correlation was also done to establish the relationship of extraction rate constant and initial extraction rate with respect to temperature. Both parameters were found to increase with increase temperature. Finally, a three-dimensional model was predicted to show the capacity of extraction at all times and temperatures of extraction. This predicted model exhibited good fitting to experimental values with low standard deviation.

Modeling Human Factors Topics in Aviation Reports

This paper describes the development and new application of a text modeling process for identifying human factors topics, such as fatigue, workload, and distraction in aviation safety reports. Current approaches to identifying human factors topic representations in text data rely on manual review from subject matter experts. The implementation of a semi-supervised text modeling method overcomes the need for lengthy manual review through an initial extraction of pre-defined human factors topics, freeing time for focus on analyzing the information. This modeling approach allows analysts to use keywords to define topics of interest up front and influence the convergence of the model toward a result that reflects them, which provides an advantage over classic topic modeling approaches where domain knowledge is not integrated into the generation of derived topics. This paper includes a description of the modeling approach and rationale, data used, evaluation methods, challenges, and suggestions for future applications.

Grey zones of production: Discussing the technology of tools at the Lojanik quarry in west-central Serbia

Flaked stone artefacts found on the quarry Lojanik in west-central Serbia are good examples of how the function of non-diagnostic pieces could be determined through technological and use-wear analysis. In this study, we present the examples of surface clusters and artefacts from stratigraphic layers. Our attention is focused on the prevailing category of fragmented raw materials in the initial phase of knapping, preforms, debris, shattered pieces of anthropogenic origin and an immense number of artefacts and geofacts. The study of mines and quarries, as well as distribution of the raw materials that come from the central Balkans is an understudied phenomenon. Flaked stone artefacts found on the outcrops of the Lojanik hilltop is a good example of how we can apply technological, petrological and use-wear analysis on this type of site. Keeping in mind the loose context of the finds, as well as the lack of any datable material, this issue has to be approached with a lot of caution, since the locality itself seems to show human presence during Palaeolithic, Neolithic and Chalcolithic. The main focus of the study was put on the prevailing categories linked to the initial extraction of raw material on the site, as well as initial steps of shaping the raw material into cores. Samples were collected from several outcrops and so-called workshops from two localities of the hilltop: Lojanik 1 and Lojanik 2. The focal points of interest are categories that include waste, shatter, technical or shaping flakes. Worked pieces of raw material are now in the central position, and the study of these pieces have opened new grounds for this and similar occurrences - the study of so-called “grey zones” of production.

Preliminary Study: Kinetics of Oil Extraction from Sandalwood by Microwave-assisted Hydrodistillation

Sandalwood and its oil, is one of the oldest known perfume materials and has a long history (more than 4000 years) of use as mentioned in Sanskrit manuscripts. Sandalwood oil plays an important role as an export commodity in many countries and its widely used in the food, perfumery and pharmaceuticals industries. The aim of this study is to know and verify the kinetics and mechanism of microwave-assisted hydrodistillation of sandalwood based on a second-order model. In this study, microwave-assisted hydrodistillation is used to extract essential oils from sandalwood. The extraction was carried out in ten extraction cycles of 15 min to 2.5 hours. The initial extraction rate, the extraction capacity and the second-order extraction rate constant were calculated using the model. Kinetics of oil extraction from sandalwood by microwave-assisted hydrodistillation proved that the extraction process was based on the second-order extraction model as the experimentally done in three different steps. The initial extraction rate, h, was 0.0232 g L-1 min-1, the extraction capacity, CS, was 0.6015 g L-1, the second-order extraction rate constant, k, was 0.0642 L g-1 min-1 and coefficient of determination, R2, was 0.9597.

Effect of temperature on the evolution of colour during the maceration of fruits in liquor

The effect of temperature on the kinetics of pigment extraction during the maceration of different fruits (raspberry, blackberry, and cranberry) into a commercially available hard spirit (orujo, with 42% v/v ethanol) was evaluated. The analytical method used was UV-Vis spectrophotometry. The initial extraction rate showed an Arrhenius-type dependence with apparent energy activation of 28.8, 69.8, and 55.6 kJ/mol, respectively. Furthermore, a study about the evolution of the colour (from colourless to reddish colour appearance) during the soaking process was done by calculating the CIE tristimulus values (X, Y, Z) for illuminant C, until reaching the apparent stabilisation of colour, which occurs after about two to four weeks for the studied temperatures (5, 23, and 40°C). Studies about the evolution of colour in the soaking process of this kind of fruit liquors can lead to a better understanding of this process, and thus to a better control over the mechanisms underlying it.