scholarly journals A bezel of an automotive headlamp: scrap/virgin ratio effects on its physicochemical properties due to the use of recycled polycarbonate

2016 ◽  
Vol 26 (3) ◽  
pp. 50-62
Author(s):  
Etzail Vega ◽  
J. A. González-Calderón ◽  
Antonio Villegas ◽  
Raúl Montiel ◽  
Elías Pérez ◽  
...  
Keyword(s):  
Surface Properties ◽  
Chemical Structure ◽  
Chemical Properties ◽  
Chain Scission ◽  
Operating Conditions ◽  
Recycling Process ◽  
Injection Process ◽  
Physical Chemical ◽  
Process Fluid ◽  
Recycled Material

Automotive bezels of polycarbonate (PC) were prepared in this work by varying the amount of recycled polymer in order to estimate an acceptable scrap/virgin ratio that maintains the material properties. Conducted tests allow us to define the limit to don't compromise the performance of recycled pieces. The studied properties were their chemical structure, molecular weight distribution, mechanical and surface properties of the samples. Results showed no change in the chemical structure of PC chains. However, variations in molecular distribution was observed by the addition of recycled material. Last one ascribed to chain scission at the carbonyl group of the PC molecules, and the formation of physical cross-linking as a consequence of degradation due to injection process. Both stiffness and surface properties of the material increased as the percentage of recycled PC rose. Therefore, although the chemical structure of the PC is preserved during the recycling process, fluid and elastic properties are modified limiting their operating conditions and industrial tolerance. Conducted analysis allows to establish that the addition to virgin PC of 20% of recycled material don't affect the physical-chemical properties of pieces, also maintains the quality standars of cosmetics tests.  

Chemical structure and physical-chemical properties of mucilage from the leaves of Pereskia aculeata

2017 ◽  
Vol 70 ◽  
pp. 20-28 ◽  
Author(s):  
Andressa Amado Martin ◽  
Rilton Alves de Freitas ◽  
Guilherme Lanzi Sassaki ◽  
Paulo Henrique Labiak Evangelista ◽  
Maria Rita Sierakowski
Keyword(s):  
Chemical Structure ◽  
Chemical Properties ◽  
Physical Chemical

scholarly journals Various Impregnation Methods Used for the Surface Modification of the Adsorbent: A Review

2018 ◽  
Vol 7 (4.7) ◽  
pp. 330 ◽  
Author(s):  
C. R. Girish ◽  
. .
Keyword(s):  
Surface Modification ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Surface Properties ◽  
Chemical Treatment ◽  
Water Contamination ◽  
Recent Time ◽  
Operating Conditions ◽  
Physical Chemical

The water contamination is an important crisis which is to be addressed in the recent time. The pollutants present in wastewater are treated by adsorption using activated carbon, which is considered as one of the effective method. The adsorbent has to be modified to improve the adsorption capacity and the surface properties. Various methods such as physical, chemical treatment, impregnation and functionalization techniques are available. Impregnation is one of the effective method carried out for surface modification and to increase the adsorption capacity. Therefore, current study investigates the different impregnation methods used for the surface modification of the adsorbent. It also reviews the various precursors used for adsorbent preparation, the impregnating agent, the operating conditions and the adsorption capacity of the adsorbent.  

Preparation of Glutinous Rice Starch Nanofibers by Electrospinning

2012 ◽  
Vol 506 ◽  
pp. 230-233 ◽  
Author(s):  
P. Jaiturong ◽  
Krit Sutjarittangtham ◽  
Sukum Eitssayeam ◽  
Jakkapan Sirithunyalug
Keyword(s):  
Chemical Structure ◽  
Chemical Properties ◽  
Rice Starch ◽  
High Porosity ◽  
High Voltage Power Supply ◽  
Electrospinning Technique ◽  
Physical Chemical ◽  
Glutinous Rice ◽  
Ft Ir ◽  
Basic Characteristics

Glutinous rice starch (GRS) is produced from glutinous rice which is commonly cultivated in the Northeast of Thailand. GRS contains two types of glucose polymers which are amylose and amylopectin. Glutinous rice starch nanofibers (GNF) can be produced by an electrospinning technique. This is not a complicated method but needs a high voltage power supply. The aim of this study was to understand the production of GNF and physical-chemical properties of GNF. The morphology of GNF was examined by scanning electron microscopy. The characteristics of GNF are high porosity, flake multi-layers and a high swelling power. The Electrospinning technique did not change the chemical structure of GRS based on an FT-IR evaluation. This research revealed the basic characteristics of electrospun glutinous starch for use in various applications in the future.

Transient Predictive Model for Dynamic Analysis, Kinetic Study, and Reactor Design of Triglycerides Transesterification to Biodiesel

2016 ◽  
Vol 14 (1) ◽  
pp. 235-249
Author(s):  
Felipe A. Perdomo-Hurtado ◽  
Rubén Vázquez-Medina
Keyword(s):  
Heat Exchanger ◽  
Batch Reactor ◽  
Mechanistic Model ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Experimental Results ◽  
Order Kinetic ◽  
Physical Chemical ◽  
Molecular Group ◽  
Biodiesel Synthesis

AbstractThis paper proposes a predictive mechanistic model to describe the classical pseudo-homogeneous second order kinetic law; the objective of the model is to study the transesterification process of any triglycerides feed stock into the synthetized biodiesel in a batch reactor, which contains a jacket heat exchanger system and a stirrer. The developed model consists of a set of ordinary differential equations which represent the mass and the energy balance for each chemical component in the reactor, accomplished by the temperature’s dynamics in the heat exchanger system, as well as, a reaction kinetic scheme, where the apparent rate and activation energies follow the Arrhenius equation (Noureddini and Zhu 1997, 1457), and the physical-chemical properties of oils, biodiesel and products have been considered. The physical-chemical properties required for products, intermediates and reactants were estimated implementing molecular group contribution methods. The constants in the reactions rates were taken directly from relevant works oriented to experimental study of the kinetic triglycerides methanolysis. The model’s usefulness was verified comparing the produced results against experimental results obtained in the biodiesel synthesis from sunflower (Vicente et al. 2005, 5447), Brassica carinata (Vicente et al. 2005, 899) and soybean (Noureddini and Zhu 1997, 1457) oils. In each case, the model matched the experimental results. Using the proposed model, it is possible to evaluate how the operating conditions and variables like the type of feed, the temperatures of the reactor and the jacket, the heat transfer, the stirrer rate and the changes on thermophysical properties of the species affect the conversion and reactor performance.

scholarly journals On the Degree-Based Topological Indices of Some Derived Networks

Mathematics ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 612 ◽  
Author(s):  
Haidar Ali ◽  
Muhammad Ahsan Binyamin ◽  
Muhammad Kashif Shafiq ◽  
Wei Gao
Keyword(s):  
Chemical Structure ◽  
Chemical Properties ◽  
Chemical Compounds ◽  
Wiener Index ◽  
Topological Indices ◽  
Theoretical Chemistry ◽  
Zagreb Index ◽  
Entire Structure ◽  
Physical Chemical ◽  
Chemical Descriptors

There are numeric numbers that define chemical descriptors that represent the entire structure of a graph, which contain a basic chemical structure. Of these, the main factors of topological indices are such that they are related to different physical chemical properties of primary chemical compounds. The biological activity of chemical compounds can be constructed by the help of topological indices. In theoretical chemistry, numerous chemical indices have been invented, such as the Zagreb index, the Randić index, the Wiener index, and many more. Hex-derived networks have an assortment of valuable applications in drug store, hardware, and systems administration. In this analysis, we compute the Forgotten index and Balaban index, and reclassified the Zagreb indices, A B C 4 index, and G A 5 index for the third type of hex-derived networks theoretically.

scholarly journals Influence of the reaction time on the quality (physical-chemical properties) of biofuels obtained through catalytic cracking of crude palm oil

2021 ◽  
Vol 17 (6) ◽  
Author(s):  
Silvio Alex Pereira Mota ◽  
Andréia Andrade Mancio ◽  
Jhuliana Silva Santanna ◽  
Valtiane de Jesus Pantoja Gama ◽  
Nélio Teixeira Machado
Keyword(s):  
Reaction Time ◽  
Specific Gravity ◽  
Palm Oil ◽  
Catalytic Cracking ◽  
Kinematic Viscosity ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Crude Palm Oil ◽  
Physical Chemical

The present paper investigated the influence of the reaction time on the quality (physical-chemical properties) of biofuels obtained by catalytic cracking of crude palm oil (CPO). The influence of the reaction time (10, 20, 30, 40, 50, and 60 min) on the quality of crude biofuels denominated organic liquid products (OLP) was investigated through experiments carried out in a cracking pilot plant with capacity of 143 L in the following operating conditions: 20 wt% sodium carbonate (Na2CO3) as catalyst, 450 °C, 1 atm and batch mode operation. The quality of the biofuels produced was certified through physical-chemical analyzes (acid value, saponification value, specific gravity, refractive index, kinematic viscosity, corrosiveness to copper, and flash point). The results show that the physical-chemical properties of OLP decrease as the reaction time increases, in such a way that, catalytic cracking process occurs efficiently in the interval of 10 to 20 min after its start, which can be finalized when it reaches 30 minutes of reaction. In addition, Na2CO3 was essential as a catalyst in the cracking reaction to reduce the physical-chemical properties of OLPs obtained at different times, allowing the specific gravity, kinematic viscosity and corrosivity to copper to be within or very close to the limits established for Diesel S10.

Improving Structure Based Models for Predicting Chemical Functions and Weight Fractions in Cosmetic Products using Ensemble Support Vector Machine

2020 ◽  
Author(s):  
Tanja B Vojinovic ◽  
Ljiljana Kascelan ◽  
Zorica Potpara ◽  
Natasa Radonjic ◽  
Zorka Kascelan
Keyword(s):  
Support Vector Machine ◽  
Chemical Structure ◽  
Chemical Properties ◽  
Toxic Chemicals ◽  
Support Vector ◽  
Cosmetic Products ◽  
Toxic Chemical ◽  
Cosmetic Product ◽  
Physical Chemical ◽  
Lack Of Information

Abstract Through usage of a large number of cosmetic products, consumers are very often exposed to toxic chemicals. This paper is aimed at proposing a model for the prediction of chemical functions and weight fractions in these products based on the structural and physical-chemical properties of the chemicals. Due to the imbalance of classes we used Support Vector Machine (SVM) method, which can complement a smaller class with the examples that are most similar to it and identify the examples that are most different. The generality of the SVM method was additionally enhanced by combining it with ensemble Bootstrap Aggregation (Bagging). The research results show that the proposed bagging SVM method can overcome the disadvantages of previously applied methods. Further, it can help address the lack of information needed to assess exposure to risk from the use of cosmetic products containing toxic chemicals in their composition. The proposed models can be applied to predict whether a certain chemical may be a substitute for a function performed by another possibly toxic chemical in a cosmetic product, as well as well as to determine the quantity proportion of a certain dangerous chemical on the basis of its chemical structure and physical-chemical properties.

scholarly journals STUDY OF THE CORRELATION BETWEEN THE CONTENT OF NANOOBJECTS AND SURFACE FEATURES

2021 ◽  
Vol 2 ◽  
pp. 47-51
Author(s):  
Natalia Kamanina
Keyword(s):  
Surface Properties ◽  
Chemical Properties ◽  
Current Paper ◽  
Surface Features ◽  
Physical Chemical ◽  
Wetting Phenomena ◽  
Good Coincidence

It is well known that at the present time two basic aspects of a material’s nano-objects sensitization should be considered. The first aspect relates to the change of the material’s basic physical-chemical properties when the concentration of the nanoobjects in the material’s body is varied. The second aspect is in regard to the modification of surface properties on the content of the nanoobjects in the material’s body. In the current paper the correlation between the concentration of the nanoobjects and wetting phenomena of the material’s surface is considered. Different experimental instruments and supporting models are presented with good coincidence.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

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