PYROLYSIS OF AROMATIC COMPOUNDS AS A GUIDE TO SYNTHETIC REACTIONS IN SEDIMENTS

1994 ◽  
Vol 34 (1) ◽  
pp. 231 ◽  
Author(s):  
J. W. Smith ◽  
S. C. George ◽  
B. D. Batts
Keyword(s):  
Aromatic Hydrocarbon ◽  
Aromatic Compounds ◽  
Crucial Role ◽  
High Concentration ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Synthetic Reactions ◽  
High Degree

The syntheses of methylaromatics by the reactions of phenanthrene, anthracene and pyrene with coals and CH4 at 220°C to 400°C is demonstrated. At temperatures not exceeding 350°C the experimental conditions may be thermally equated, in terms of R0 values, to those approximating the oil window. Therefore, the high degree of methylation achieved, the insensitivity of the methylation process to reaction conditions and the systematic and theoretically predictable increases with temperature in the ratio of the ß/α substituted methyl isomers of the parent aromatic hydrocarbon, provide support for significant geosynthetic processes in sediments. The high concentration of n-alkanes generated from the coal may play a crucial role in reactions.

scholarly journals Software-guided microscale flow calorimeter for efficient acquisition of thermokinetic data

2021 ◽  
Author(s):  
Timothy Aljoscha Frede ◽  
Marlene Dietz ◽  
Norbert Kockmann
Keyword(s):  
Design Of Experiments ◽  
Process Development ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Flow Calorimeter ◽  
Microscale Flow ◽  
Increased Sensitivity ◽  
Important Time ◽  
Optimal Reaction

AbstractFast chemical process development is inevitably linked to an optimized determination of thermokinetic data of chemical reactions. A miniaturized flow calorimeter enables increased sensitivity when examining small amounts of reactants in a short time compared to traditional batch equipment. Therefore, a methodology to determine optimal reaction conditions for calorimetric measurement experiments was developed and is presented in this contribution. Within the methodology, short-cut calculations are supplemented by computational fluid dynamics (CFD) simulations for a better representation of the hydrodynamics within the microreactor. This approach leads to the effective design of experiments. Unfavourable experimental conditions for kinetics experiments are determined in advance and therefore, need not to be considered during design of experiments. The methodology is tested for an instantaneous acid-base reaction. Good agreement of simulations was obtained with experimental data. Thus, the prediction of the hydrodynamics is enabled and the first steps towards a digital twin of the calorimeter are performed. The flow rates proposed by the methodology are tested for the determination of reaction enthalpy and showed that reasonable experimental settings resulted. Graphical abstract A methodology is suggested to evaluate optimal reaction conditions for efficientacquisition of kinetic data. The experimental design space is limited by thestepwise determination of important time scales based on specified input data.

scholarly journals Occurrence of Penta-Aromatic Hydrocarbons in Jaintia and Barail Group Mudstones, Northeastern Bengal Basin, Bangladesh

2014 ◽  
Vol 8 ◽  
pp. 105-112
Author(s):  
HM Zakir Hossain ◽  
Md Sultan-Ul-Islam ◽  
Quazi Hasna Hossain
Keyword(s):  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Concentration Distribution ◽  
Gas Chromatography Mass Spectrometry ◽  
Bengal Basin ◽  
Drill Core ◽  
Environmental Condition ◽  
High Concentration ◽  
Biogenic Origin

In the present experiment, concentration, distribution and sources of penta-aromatic hydrocarbons in seven drill core and outcrop samples from Jaintia and Barail Group mudstones, northeastern Bengal Basin, Bangladesh have been studied. Gas chromatography-mass spectrometry (GC-MS) was used to obtain composition details about the sedimentary organic matter (OM). Mudstone samples were found to contain relatively high penta-aromatic hydrocarbon abundances in the lower Jaintia Group than in the overlying Barail Group. High concentration of perylene suggests terrigenous sources and significantly higher content of total organic carbon in the samples. A biogenic origin of perylene therefore indicates oxygen deficient environmental condition for deposition of OM. Perylene over pentacyclic aromatic hydrocarbon isomers regulating in-situ diagenetic origin. DOI: http://dx.doi.org/10.3329/jles.v8i0.20154 J. Life Earth Sci., Vol. 8: 105-112, 2013

scholarly journals Evaluation of Sealing Materials Adhesion to Enamel An in vitro study

2017 ◽  
Vol 54 (1) ◽  
pp. 129-132
Author(s):  
Andreea Simona Pop ◽  
Radu Septimiu Campian ◽  
Mariana Pacurar ◽  
Elina Teodorescu ◽  
Olimpia Bunta ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Specific Method ◽  
High Concentration ◽  
Posterior Teeth ◽  
Inorganic Particles ◽  
Material Homogeneity ◽  
Materials Used ◽  
High Degree ◽  
Pits And Fissures

Sealing the pits and fissures of posterior teeth represents a local and specific method of caries prevention. The aim of this study was to evaluate the adhesion of two materials used in sealing pits and fissures: Pitt and Fisure and Fissurit FX (Voco), with the help of the scanning electronic microscope (SEM). The results of the study revealed a much higher quality of the Fissurit FX (Voco) product both in terms of adhesion to the enamel and material homogeneity. The Pitt and Fisure product showed a high degree of detachment from the enamel, marginal infiltration, large particles and a high concentration of inorganic particles.

Human placental and fetal membrane nitric oxide synthase activity before, during and after labour at term

1995 ◽  
Vol 7 (6) ◽  
pp. 1505 ◽  
Author(s):  
Iulio JL Di ◽  
NM Gude ◽  
RG King ◽  
SP Brennecke
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Caesarean Section ◽  
Normal Vaginal Delivery ◽  
Fetal Membrane ◽  
High Concentration ◽  
Experimental Conditions ◽  
Nos Inhibitor ◽  
Tissue Specimens ◽  
Oxide Synthase

The aim of this study was to determine whether any labour-associated changes in nitric oxide synthase (NOS) activity occur in human placenta and fetal membranes. NOS activity in amnion, choriodecidua, and placenta obtained from women before (at Caesarean section, not in labour), during (at Caesarean section, in labour) and after (spontaneous onset labour, normal vaginal delivery) labour was assessed by measuring conversion of radio-labelled L-arginine to L-citrulline. NOS activity, as judged by its inhibition by the specific NOS inhibitor N omega-nitro-L-arginine, was present in placental and amnionic tissues, but not in choriodecidual tissue specimens. Activity detected in choriodecidua was significantly blocked during incubation with a high concentration of valine, suggesting that L-arginine was being consumed by reactions other than NOS under the experimental conditions in that tissue. There were no significant differences among the labour groups in either amnion or placental NOS activities measured in the presence of 1 microM L-arginine. Amnion NOS activity was significantly less than that in placenta. Placental V(max) and Km values (determined after removal of endogenous L-arginine) did not differ significantly among the different labour groups.

1. International Relations Theory and the Middle East

2019 ◽  
pp. 21-38
Author(s):  
Fred H. Lawson
Keyword(s):  
Middle East ◽  
International Relations ◽  
Crucial Role ◽  
Structural Realism ◽  
International Relations Theory ◽  
English School ◽  
Alternative Perspective ◽  
The Many ◽  
High Degree ◽  
Neoliberal Institutionalism

This chapter discusses the different theories and approaches that characterize the study of international relations. Mainstream theories focus on the ways that states interact with one another in circumstances where no overarching authority governs their behavior — in other words, under conditions of anarchy. These theories include structural realism, neoliberal institutionalism, and the scholarship on relational contracting. An important alternative perspective — the English School — argues that, even under anarchic conditions, there is a high degree of orderliness in world affairs. Meanwhile, proponents of constructivism assert that states take shape in specific historical contexts, and that the conditions under which states coalesce and become socialized to one another play a crucial role in determining how they conceive of themselves and formulate their basic interests. Scholars of the Middle East have so far addressed only a fraction of the many theoretical debates and controversies that energize the field of international relations.

Significance of Qualitative Factors for a Deeper Understanding of Service Productivity

2013 ◽  
Vol 4 (2) ◽  
pp. 46-59 ◽  
Author(s):  
Sabrina Cocca
Keyword(s):  
Crucial Role ◽  
Processing Time ◽  
Service Management ◽  
Black Box ◽  
Process Efficiency ◽  
Input Output ◽  
Service Productivity ◽  
Qualitative Factors ◽  
High Degree ◽  
Measurable Factors

Analysing and optimising service productivity is a widely discussed task in service management. While directly measurable factors such as processing time or service turnover are frequently used in order to measure the productivity of services, underlying factors that are, in many cases, not (directly) measurable are not considered in-depth. However, these “qualitative” factors influence service productivity to a high degree. The idea behind the approach provided in this article is to open the former “black box” view on productivity (input–output) to a process efficiency-oriented perspective instead and to show which qualitative factors play a crucial role regarding service productivity.

scholarly journals Cave Drip Water-Related Samples as a Natural Environment for Aromatic Hydrocarbon-Degrading Bacteria

2019 ◽  
Vol 7 (2) ◽  
pp. 33 ◽  
Author(s):  
Eric Marques ◽  
Gislaine Silva ◽  
João Dias ◽  
Eduardo Gross ◽  
Moara Costa ◽  
...  
Keyword(s):  
Aromatic Hydrocarbon ◽  
Microbial Communities ◽  
16S Rdna ◽  
Aromatic Compounds ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Amplicon Sequencing ◽  
Drip Water ◽  
Rdna Sequencing ◽  
Degrading Bacteria ◽  
Cave Drip Water

Restricted contact with the external environment has allowed the development of microbial communities adapted to the oligotrophy of caves. However, nutrients can be transported to caves by drip water and affect the microbial communities inside the cave. To evaluate the influence of aromatic compounds carried by drip water on the microbial community, two limestone caves were selected in Brazil. Drip-water-saturated and unsaturated sediment, and dripping water itself, were collected from each cave and bacterial 16S rDNA amplicon sequencing and denaturing gradient gel electrophoresis (DGGE) of naphthalene dioxygenase (ndo) genes were performed. Energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) were performed to evaluate inorganic nutrients, and GC was performed to estimate aromatic compounds in the samples. The high frequency of Sphingomonadaceae in drip water samples indicates the presence of aromatic hydrocarbon-degrading bacteria. This finding was consistent with the detection of naphthalene and acenaphthene and the presence of ndo genes in drip-water-related samples. The aromatic compounds, aromatic hydrocarbon-degrading bacteria and 16S rDNA sequencing indicate that aromatic compounds may be one of the sources of energy and carbon to the system and the drip-water-associated bacterial community contains several potentially aromatic hydrocarbon-degrading bacteria. To the best of our knowledge, this is the first work to present compelling evidence for the presence of aromatic hydrocarbon-degrading bacteria in cave drip water.

scholarly journals Propane Pre-Reforming into Methane-Rich Gas over Ni Catalyst: Experiment and Kinetics Elucidation via Genetic Algorithm

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3393 ◽  
Author(s):  
Sergey I. Uskov ◽  
Dmitriy I. Potemkin ◽  
Leniza V. Enikeeva ◽  
Pavel V. Snytnikov ◽  
Irek M. Gubaydullin ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Molar Ratio ◽  
Ni Catalyst ◽  
Propane Conversion ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Chromium Catalyst ◽  
Nickel Chromium ◽  
Wide Range ◽  
The Given

Pre-reforming of propane was studied over an industrial nickel-chromium catalyst under pressures of 1 and 5 bar, at a low steam to carbon molar ratio of 1, in the temperature range of 220–380 °C and at flow rates of 4000 and 12,000 h−1. It was shown that propane conversion proceeded more efficiently at low pressure (1 atm) and temperatures above 350 °C. A genetic algorithm was applied to search for kinetic parameters better fitting experimental results in such a wide range of experimental conditions. Power law and Langmuir–Hinshelwood kinetics were considered. It was shown that only Langmuir–Hinshelwood type kinetics correctly described the experimental data and could be used to simulate the process of propane pre-reforming and predict propane conversion under the given reaction conditions. The significance of Langmuir–Hinshelwood kinetics increases under high pressure and temperatures below 350 °C.

Preliminary Study on the Removal of Hexavalent Chromium in Wastewater with Reduction of Sulfur Dioxide

2013 ◽  
Vol 864-867 ◽  
pp. 1699-1703
Author(s):  
Ji Ming Wu ◽  
Sheng Gao Cheng
Keyword(s):  
Reaction Time ◽  
Sulfur Dioxide ◽  
Hexavalent Chromium ◽  
Reduction Reaction ◽  
High Concentration ◽  
Reaction Conditions ◽  
Ph Values ◽  
Different Temperatures ◽  
Preliminary Study ◽  
High Concentrations

The paper focused on a self-developed methodology through using sulfur dioxide to deal with high concentration of chromium-containing wastewater. It studied the effects of different pH values, different reaction time, different temperatures and different amounts of sulfur with sulfur dioxide reduction reaction on the chromium-containing wastewater. The results showed that: when the reaction conditions were controlled as follows: the pH values ranged from 2 to 4, the reaction temperature was controlled 40~60°C, the amount of sulfur in theoretical was 1.2 times and the reaction time was 40 min, the hexavalent chromium in the high concentrations of chromium-containing wastewater could be effectively removed.

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