Conversion Of Different Types Research Articles

Analysis of color stability and degree of conversion of different types of resin composites.

Resin composites containing surface pre-reacted glass (S-PRG) have been introduced to reduce demineralization and improve remineralization of the tooth structure. However, water diffusion within the material is necessary for its action, which can impair its overall physicomechanical properties over time, including color stability. This study aimed to evaluate the color stability and related degree of conversion (DC) of four resin composites. Discs (6 x 4 mm, n = 5/group) of microhybrid (MH), nanofilled (NF), nanohybrid (NH), and S-PRG-based nanohybrid (S-PRG-NH) composites with two opacities (A2/A2E and A2O/A2D) were prepared. Color (CIELab and CIEDE2000) was evaluated with a spectrophotometer after aging in grape juice (2 x 10 min/10mL/7days). The DC was analyzed by using Fourier transform infrared spectroscopy before and after light-curing. Data were statistically analyzed by using two-way analysis of variance and post-hoc least significant difference tests (p<0.05). In the color stability analysis, the interaction between filler type and opacity was significant (CIELab, p = 0.0015; CIEDE2000, p = 0.0026). NH presented the highest color stability, which did not differ from that of MH. The greatest color alteration was observed for S-PRG-NH. S-PRG fillers also influenced DC (p < 0.05). The nanohybrid resin composite presented favorable overall performance, which is likely related to its more stable organic content. Notwithstanding the benefits of using S-PRG-based nanohybrid resins, mostly in aesthetic procedures, professionals should consider the susceptibility of such resins to color alteration, probably due to the water-based bioactive mechanism of action.

Recent trends of plastic waste management for sustainable environment in Indian context

One of the most rapidly expanding waste streams in municipal solid waste worldwide is plastic waste. Due to their non-decaying, large quantities and difficulties in disposing of them, waste plastics have become a significant threat to the environment. India has ranked 12th among the countries with improper management of waste plastics, but it is projected that it will be ranked 5th by the year 2025. Energy recuperation from pyrolysis of plastic waste in the form of liquid fuel is acquiring fascination overall by meeting the difficulties of energy security and natural assurance. A brief overview about the conversion of different types of plastic waste into fuel and summary of the results emphasising the utilization of fuel as a replacement of diesel is presented in this paper. The different operating parameters of pyrolysis process, their impact on yield, constraints of the implementation in large scale of this technology and recent technological advancements have been covered in this review. The review has also discussed the Indian government policies on plastic waste management, challenges and future scope.

Room Temperature Synthesis of Bioactive 1,2,4-Oxadiazoles.

1,2,4-Oxadiazole is an essential motif in drug discovery represented in many experimental, investigational, and marketed drugs. This review covers synthetic methods that allow the conversion of different types of organic compounds into 1,2,4-oxadiazole at ambient temperature and the practical application of the latter approaches for the preparation of pharmaceutically important molecules. The discussed methods are divided into three groups. The first combines two-stage protocols requiring the preliminary preparation of O-acylamidoximes followed by cyclization under the action of organic bases. The advantages of this route are its swiftness, high efficiency of the cyclization process, and uncomplicated work-up. However, it requires the preparation and isolation of O-acylamidoximes as a separate preliminary step. The second route is a one-pot synthesis of 1,2,4-oxadiazoles directly from amidoximes and various carboxyl derivatives or aldehydes in aprotic bipolar solvents (primarily DMSO) in the presence of inorganic bases. This recently proposed pathway proved to be highly efficient in the field of medicinal chemistry. The third group of methods consists of diverse oxidative cyclizations, and these reactions have found modest application in drug design thus far. It is noteworthy that the reviewed methods allow for obtaining 1,2,4-oxadiazoles with thermosensitive functions and expand the prospects of using the oxadiazole core as an amide- or ester-like linker in the design of bioactive compounds.

Niobium: The Focus on Catalytic Application in the Conversion of Biomass and Biomass Derivatives.

The world scenario regarding consumption and demand for products based on fossil fuels has demonstrated the imperative need to develop new technologies capable of using renewable resources. In this context, the use of biomass to obtain chemical intermediates and fuels has emerged as an important area of research in recent years, since it is a renewable source of carbon in great abundance. It has the benefit of not contributing to the additional emission of greenhouse gases since the CO2 released during the energy conversion process is consumed by it through photosynthesis. In the presented review, the authors provide an update of the literature in the field of biomass transformation with the use of niobium-containing catalysts, emphasizing the versatility of niobium compounds for the conversion of different types of biomass.

Evaluation of Degree of Conversion of Different Types of Bulk-fill Resin Composites

Evaluation of Degree of Conversion of Different Types of Bulk-fill Resin Composites

The Heterogeneous Impact of High-Speed Railway on Urban Expansion in China

High-speed railway (HSR) promote the efficient flow of the population and materials between cities and have profoundly affected urban economic development in China. However, there is currently limited research about how HSR influences urban expansion, especially related to the variable impacts on different urban agglomerations, different size cities, and the conversion of non-urban land to urban land. In this study, from two levels of regional heterogeneity and type heterogeneity, a multi-stage difference-in-differences (multi-stage DID) model and land use remote sensing data are used to investigate these research areas. The main conclusions are as follows: (1) The first opening of HSR had a more significant role in promoting urban expansion than HSR frequency, but several years after opening, HSR no longer promotes urban expansion. (2) The opening of HSR only played a significant role in promoting urban expansion in Beijing–Tianjin–Hebei. HSR frequency had a significant role in promoting urban expansion in the Yangtze River Delta. (3) The opening of HSR had no significant impact on urban expansion for different size cities, and HSR frequency only had a significant negative impact on urban expansion of small cities. (4) The first opening of HSR led to urban expansion dominated by the occupation of cultivated land. Cities in Xinjiang and Inner Mongolia mainly converted barren land and vegetation cover to urban land after the first opening of HSR. In northeast China, the first opening of HSR made the conversion of vegetation cover and cultivated land to urban land roughly equivalent in size. The results of this study are helpful to understand the impact of the first opening of HSR and the scale of conversion of different types of non-urban land into urban land on urban expansion. In the era of HSR, these findings provide a valuable reference for regional planning and preventing the disorderly expansion of cities.

A comprehensive review of renewable and sustainable biosourced carbon through pyrolysis in biocomposites uses: Current development and future opportunity

Highly order-structured carbon-based materials such as graphite, graphene, and carbon nanotubes hold promise in delivering the next generation of carbon-based advanced composite materials due to their superior performance in many applications. Recently, partially graphitic biosourced carbon (BioC) has shown to be a new, sustainable, inexpensive and practical alternative carbonaceous functional filler for polymer and biocomposite development (i.e. thermoplastic, thermoset, elastomer and foam). The thermochemical conversion of different types of biomass in a limited oxygen environment (pyrolysis) can be controlled and optimized to produce engineered BioCs with tunable surface area, morphology, polarity, porosity, intrinsic modulus and carbon content, which are being explored in different applications. Renewable BioCs exhibit variable surface chemistry that can be further modified to achieve better compatibility with polymers. BioC can be used as a reinforcing agent and as a multi-functional filler (e.g. electrical conductivity, antimicrobial, fire retardant, etc.) for polymer composite uses, which opens a new generation of biobased composite materials in the commercial market. This article provides an in-depth review of the current state-of-the-art fabrication, characterization, and performance of the BioC-based biocomposites. Further, the effect of the different synthesized BioCs on the polymers’ behavior and performance are reviewed in-depth. Finally, the challenges and future perspectives for these BioC-based biocomposites are discussed.

Are there differences in the forces driving the conversion of different non-urban lands into urban use? A case study of Beijing.

Examining the heterogeneous factors behind the conversion of various types of non-urban land into urban use is of great significance for controlling urban land expansion and formulating reasonable land use policies. Taking Beijing as an example, this study identified the spatial patterns of urban expansion in China's large cities and then explored the different driving factors behind its various sources. The results showed that, from 2001 to 2010, Beijing's urban land presented a compound expansion mode in which multiple spatial modes coexisted. Urban encroachment contributed differently to the loss of different non-urban lands. Cultivated land and ecological land were the main sources of newly developed urban land, of which the conversion was driven jointly by topography, location, transportation, socioeconomic development, and spatial planning. Moreover, the main factors behind the conversion of various land types varied: closing to existing built-up area and infrastructures increases the conversion probability of most land types; socioeconomic development has common but differentiated effects; governments at different levels have their influences on the conversion of different types of non-urban land. Based on the results, this study suggested the importance of considering varied approaches in managing non-urban lands to better controlling their conversion into urban use and the different roles that could be played by governments at various levels.

Fate of phosphorus and potassium in single-pellet thermal conversion of forest residues with a focus on the char composition

The phosphorus and potassium contents of the char obtained from thermal conversion of forest residues can limit its utilization as an alternative fuel and reducing agent to substitute coal/coke in the steelmaking industry. In this study, ash transformation and release of K and P during single-pellet thermal conversion of different types of forest residues (i.e., bark, twigs, and bark+twigs) were investigated with the aid of a vertical tube furnace (Macro-TGA) at different temperatures (i.e., 600, 800, and 950 °C) and within and after different fuel conversion stages, i.e., devolatilization and char gasification. The residual char before and after full devolatilization, and ash after char gasification were characterized by SEM-EDS, XRD, and ICP-OES with the support of thermochemical equilibrium calculations. The concentrations of K (7970–19500 mg/kg) and P (1440–4925 mg/kg) in the char produced after devolatilization were more than four times higher than in coke and pulverized coal frequently used in metallurgical processes. A low amount of P and K (≤15%) were released from all fuels. K and P were evenly distributed within the char residues, and no crystalline compounds containing K and P were found. In ash residues of bark, K was found in K2Ca2(CO3)3, and K2Ca(CO3)2. K in ash residues from twigs and bark+twigs was mainly found in the amorphous part of ash, most likely in the form of K-Ca rich silicates. Apatite was found as the main P crystalline compound in all ashes at all temperatures. Estimations show that a release of more than 80% is needed for the studied forest residual assortments to reach K and P concentrations typical of blast furnace coals and cokes.

Stochastic day-ahead scheduling of multiple energy Carrier microgrids with demand response

Microgrids are indispensable components of active energy systems that supply diverse electrical and thermal demands. A microgrid is composed of distributed energy resources (DER) including renewable resources, combined heat and power generation (CHP) and conventional generation resources that rely on fossil fuels. Energy hubs in microgrids facilitate the conversion of different types of energy resources. The coupling among natural gas and electricity distribution networks introduces new challenges to the short-term operation planning of microgrids. In this paper, a two-stage stochastic optimization problem is formulated for the short-term operation planning of microgrids with multiple-energy carrier networks to determine the scheduled energy and reserve capacity. The problem is formulated as a mixed integer linear programming problem in which the objective function is to minimize the expected operation cost in the short-term operation horizon. The uncertainties in the renewable generation including the wind and solar photovoltaic generation, and electrical and thermal demands are captured by introducing scenarios with respective probabilities. The proposed solution framework ensures the reliability and security of energy supply in multiple scenarios. The advantage of capturing the interdependence among the electricity and natural gas systems to promote energy efficiency is presented. Furthermore, the effectiveness of demand response programs to reduce the operation costs and improve the security measures is investigated. The sensitivity of the operation costs to the variation of natural gas flow and congestion in pipelines and energy prices is addressed to highlight the interdependence among natural gas and electricity infrastructure systems.

Enzyme preparations and biocatalytic processes in the food industry

Enzyme preparations are essential to biotechnological processes for the production of food. Classification of enzymes, the specificity of their action on various substrates and processes of obtaining enzyme preparations based on various microorganisms-producers of enzymes are presented. Overview of the world and internal market of enzyme preparations used in the food industry is provided. The issues of efficient bioconversion of different plant materials to improve the quality of juices, fruit drinks, reducing the viscosity and increasing the productivity of biologically valuable components for functional products are considered; microbial raw materials - to produce protein or amino acid and vitamin enriched foods, as well as food ingredients; animal raw materials - for intensification of technological processes, for processing of wastes of meat, dairy industry, as well as in cheese making to improve the quality of products. The review is of scientific and practical interest for specialists in the field of biotechnology of food production of high quality food obtained by the enzymatic conversion of different types of agricultural raw materials.

Religion and Social Class: Theory and Method after Bourdieu

This article outlines two inter-related but distinct theoretical approaches to the study of Christianity and Social Class developed from the work of Pierre Bourdieu. The first is a model derived from Distinction (Bourdieu [1979] 1984), the second comes from Bourdieu's work on religious fields with a focus on the conversion of capital between different fields. The former, better known, approach has the potential to provide important insights, including identifying the affinity of different religious groups with different class locations; on the other hand, this would tell us little about the internal workings of religious communities; it is also unfortunately hampered by a lack of suitable data. The conception of fields and their inter-relations will not answer the questions about the affinity of particular class fragments for particular kinds of religiosity, but it does provide much keener insight into the operation of class within religious communities, by examining the conversion of different types of capital into religious capital. This is illustrated with an extended Bourdieusian hypothesis, a schematic outline that could be used as the starting point for empirical research on the operation of different kinds of capital in the Church of England.

Сучасні тенденції зміни суб’єктності публічної політики

У статті аналізується проблема інституціоналізації публічних акторів і форм їх взаємодії в сучасному постмодерновому політичному просторі. Виявлено і охарактеризовано нові тенденції зміни їх суб’єктності у формуванні громадського капіталу в різних типах режимів: гібридизація, мережевість, індивідуалізація, транскордонність, конфліктність. Оцінено вплив інформаційних технологій, які стають одним з головних інструментів реалізації публічної політики в сучасних політичних умовах і яких у перспективі можна розглядати в якості основи трансформації політичних систем всіх типів. Визначено, що ключовим механізмом розвитку політичних практик акторів є конвертація різних видів ресурсів в публічний капітал, який є частиною політичного капіталу. З’ясовано, що публічні актори діють в конкретних інституційних режимних рамках, мають інкорпоровану здатність брати участь в колективних та індивідуальних діях, грунтуючись на своїх інтересах, перевагах і ідентичностях. В роботі доведено, що публічні актори, перебуваючи в певному режимному середовищі, формують особливі форми публічного капіталу, який відображає ступінь ефективності, відкритості та конфліктності політичної системи.

Two-stage pyrolytic conversion of different types of biomass into synthesis gas

Possibilities of using the method of two-stage pyrolytic processing of the main types of biomass for the production of synthesis gas are considered. A comparison of the biomass characteristics (volatile content, ash content, elemental composition, and heating value) and the characteristics of gas mixtures obtained from it (volume, composition, and heating value) is performed. From the results obtained, it follows that the considered method of pyrolytic processing allows obtainment of 1.25 to 1.39 m3 of synthesis gas (per kg of combustible mass of the raw material) with heating value at 10–12 MJ/m3, and a high degree of energy conversion as compared with other methods for biomass gasification.

Biomass Conversion into Solid Composite Fuel for Bed-Combustion

The purpose of this research is the conversion of different types of biomass into solid composite fuel. The subject of research is the heat conversion of biomass into solid composite fuel. The research object is the biomass of the Tomsk region (Russia): peat, waste wood, lake sapropel. Physical experiment of biomass conversion is used as method of research. The new experimental unit for thermal conversion of biomass into carbon residue, fuel gas and pyrolysis condensate is described. As a result of research such parameters are obtained: thermotechnical biomass characteristics, material balances and product characteristics of the heat-technology conversion. Different methods of obtaining solid composite fuel from the products of thermal technologies are considered. As a result, it is established: heat-technology provides efficient conversion of the wood chips and peat; conversion of the lake sapropel is inefficient since the solid composite fuel has the high ash content and net calorific value.

Removal of Tartrazine Dye onto Mixed‐Waste Activated Carbon: Kinetic and Thermodynamic Studies

Numerous studies have been performed on the conversion of individual types of waste into activated carbon (AC). However, this study focused on the evaluation of the simultaneous conversion of different types of wastes (palm, paper, and plastic wastes) into AC via copyrolysis. The tartrazine adsorption capacity onto the produced AC was optimized. The results showed that the carbon content of the AC improved as the calcium hydroxide concentration varied from 0.0 to 2.0 mol L−1. In addition, the volatile matter and ash content were reduced as the concentration of calcium hydroxide was increased from 0.0 to 2.0 mol L−1. The tartrazine adsorption capacity of the prepared AC samples increased as the calcium hydroxide concentration increased from 0.5 to 2 mol L−1 at a carbonization temperature of 400°C for 2 h and a final activation temperature of 500°C for 1 h. Effective adsorption occurred at pH 2. The maximum adsorption capacity (74.9 mg g−1) was obtained with a contact time of 300 min and an initial tartrazine concentration of 150 ppm. The adsorption kinetics of tartrazine were modeled with pseudo‐first order, pseudo‐second order, and intraparticle diffusion models, which revealed that the tartrazine adsorption onto the AC showed a best fit with the pseudo‐second order kinetic model. The thermodynamic parameters ΔG0, ΔH0, and ΔS0 indicated that the adsorption of tartrazine onto the AC was spontaneous and endothermic. The values of ΔG0 were between −1.3 and −2.3 kJ mol−1, and the ΔH0 and ΔS0 values, in the temperature range of 25–50°C, were 9.12 kJ mol−1 and 35.5 J mol−1 K−1, respectively. In general, the thermodynamic parameters indicate that the adsorption is spontaneous and endothermic.

Evaluation of the Influence of Three Types of Light Curing Systems On Temperature Rise, Depth of Cure and Degree of Conversion of Three Resin Based Composites (An In vitro study)

Aim of study: The purpose of this study was to evaluate the effect of Quartz tungsten halogen, Light emitted diode & soft start light curing units on temperature rise, depth of cure & degree of conversion of different types of dental composites (Spectrum, Esthet X & Z250). Methodology: Thirty sound, single–rooted human bicuspids extracted for orthodontic purpose were used to measure the temperature rise inside the pulp chamber by using a needle probe, connected to thermocouple thermometer through the apical foramen. Ninety specimens of dental composites (Spectrum, Esthet X & Z250) were prepared by using special mold to determine the depth of cure of different light curing modes (Quartz tungsten halogen, Light emitted diode & soft start) by using the scraping method described by ISO standard for polymer –based filling restorative & luting materials. For the assessment of the degree of conversion, eighteen samples of dental composites were tested by the Fourier – transformed infrared spectrometry according to the standard baseline technique of Rueggeberg et al., 1990. Result and Conclusion: QTH light curing showed the highest temperature rise value, while the soft start gave the lowest values. Soft start light curing revealed the highest depth of cure values, while the QTH showed the lowest values among three curing modes. There were overall statistical significant differences in the depth of cure values among groups of different curing systems & types of dental composites. Soft start light curing system showed the highest degree of conversion and QTH had the lowest values. Esthet X dental composite gave the highest results of the degree of conversion while Z250 showed the lowest values.

Catalytic reforming of hydrocarbon feedstocks into fuel for power generation units

The feasibility of realization of the multifuel operation principle, specifically, production of a hydrogen-containing gas from various types of hydrocarbon feedstocks using the same catalyst under similar reaction conditions is considered. The steam reforming of two types of hydrocarbon mixtures, namely diesel fuel satisfying GOST (State Standard) R 52368-2005 (EN 590:2004) and a methane-propane mixture imitating the composition of associated petroleum gas, has been investigated to clarify this issue. These hydrocarbon feedstocks were chosen for the reason that they are universally used as a fuel for various types of power generation units. Experiments have been carried out in a catalytic flow reactor at 250–480°C (for the methane-propane mixture) and 500–600°C (for diesel fuel) and pressures of 1–15 atm using a nickel-containing catalyst (NIAP-18). This catalyst has been demonstrated to ensure conversion of different types of hydrocarbon feedstocks into synthesis gas and methane-hydrogen mixtures usable as a fuel for power generation units based on high-temperature fuel cells and for spark-ignition, diesel, and gas-diesel engines.

Chemical Kinetic Modeling in Coal Gasification Processes: an Overview

&lt;p&gt;Coal is the fuel most able to cover world deficiencies in oil and natural gas. This motivates the development of new and more effective technologies for coal conversion into other fuels. Such technologies are focused on coal gasification with production of syngas or gaseous hydrocarbon fuels, as well as on direct coal liquefaction with production of liquid fuels. The benefits of plasma application in these technologies is based on the high selectivity of the plasma chemical processes, the high efficiency of conversion of different types of coal including those of low quality, relative simplicity of the process control, and significant reduction in the production of ashes, sulphur, and nitrogen oxides. In the coal gasifier, two-phase turbulent flow is coupled with heating and evaporation of coal particles, devolatilization of volatile material, the char combustion (heterogeneous/porous oxidation) or gasification, the gas phase reaction/oxidation (homogeneous oxidation) of gaseous products from coal particles. The present work reviews literature data concerning reaction kinetic modelling in coal gasification. Current state of related kinetic models for heterogeneous/homogeneous oxidation of coal particles, included plasma assisted, is reviewed.&lt;/p&gt;

Effect of feedstock composition on product yields and energy recovery rates of fast pyrolysis products from different straw types

The conversion of different types of straw by fast pyrolysis has been investigated in this study. The mass and energy balance for corn stover, wheat straw and also rape and sunflower stalks are reported. A process development unit with a twin screw mixer reactor has been utilised for the experiments with a feeding rate of 10kg/h at fixed operation conditions of reactor temperature, cooling temperature, vapour residence time, biomass particle size and heat carrier material. The results in product yields and energy recovery rates are compiled and compared. It can be observed that different types of straw produce different char, condensate and gas mass yields due to their varying ash content and differing lignocellulosic composition. On a dry and ash-free basis elemental formulas for feedstock, char, organic condensate and gas could be defined independent of the feedstock due to similar elemental compositions. Gas flow rate and composition measurements provide additional information on mass yields: a CO/CO2-ratio of 1 (i.e. wood) corresponds to an organic condensate yield of about 50wt.%, whereas a ratio of 0.3–0.7 (straw) corresponds to about 18–32wt.%.