Dispersion of Pigments in Rubber—II

1929 ◽  
Vol 2 (4) ◽  
pp. 656-667 ◽  
Author(s):  
Ernst A. Grenquist
Keyword(s):  
Special Reference ◽  
Experimental Evidence ◽  
Chemical Properties ◽  
Experimental Results ◽  
Rubber Compound ◽  
Physical Chemical ◽  
Natural Resins ◽  
Theoretical Conception ◽  
Correct Understanding ◽  
Vulcanization Process

Abstract A theoretical conception of the reënforcement of rubber by pigments has been developed. New experimental evidence has been presented which leads to a better understanding of the final dispersion and reënforcement of a rubber compound. It is shown that pigment reënforcement is influenced by (a) rubber structure, (b) the state of aggregation of proteins and natural resins, (c) the isotropic properties of carbonblack particles, and (d) the presence of recrystallized rhombic sulfur at the beginning of vulcanization. A PREVIOUS paper (10)* described the distribution of particles in compounded rubber with special reference to agglomeration and flocculation. It was emphasized that a correct understanding of the final dispersion and reënforcement of a rubber compound could only be obtained with a more thorough knowledge of the structure and physical-chemical properties of rubber and pigments themselves and of the nature of the vulcanization process. New experimental results in regard to these particular points are presented in the following investigation.

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.

Size Effect and Shape Stability of Nanoparticles

2010 ◽  
Vol 444 ◽  
pp. 47-68 ◽  
Author(s):  
J.L. Rodríguez-López ◽  
J.M. Montejano-Carrizales ◽  
J.P. Palomares-Báez ◽  
H. Barrón-Escobar ◽  
J. Jesús Velázquez-Salazar ◽  
...  
Keyword(s):  
Energy Storage ◽  
Chemical Synthesis ◽  
Size Effect ◽  
Metallic Nanoparticles ◽  
Wide Spectrum ◽  
Chemical Properties ◽  
Experimental Results ◽  
Applied Physics ◽  
Shape Stability ◽  
Physical Chemical

Nanoparticle research disciplines—chemical synthesis, applied physics and devices based on their physical-chemical properties, and computational physics—have been very active fields for the last 15 years or so, because of the potential and current applications in medicine, catalysis, energy storage, environment and electronics applications. This wide spectrum of disciplines and their applications keep metallic nanoparticles as one of the most promising nanostructures and their research as one of the cornerstones of nanotechnology. In this contribution we present a comprehensive and extended geometrical description for the most common shapes and structures for metallic nanoparticles, as well as experimental results for these geometries with some variations given by truncations.

Chlorinated Organics in Nearshore Waters and Tributaries of the St. Clair River

1986 ◽  
Vol 21 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Barry G. Oliver ◽  
Klaus L.E. Kaiser
Keyword(s):  
United States ◽  
Suspended Sediment ◽  
Waste Disposal ◽  
Large Volume ◽  
Water Samples ◽  
Chemical Properties ◽  
Low Level ◽  
Chemical Company ◽  
Physical Chemical ◽  
The Individual

Abstract The concent rat ions of hexachloroethane (HCE), hexachlorobutadiene (HCBD), pentachlorobenzene (QCB), hexachlorobenzene (HCB) and octachlorostyrene (OCS) in large volume water samples show that the major sources of these chemicals to the St. Clair River are Dow Chemical Company effluents and, to a lesser degree, Sarnia’s Township ditch which drains one of Dow’s waste disposal sites. Tributaries entering the river on both sides of the Canada/United States border contain measurable concentrations of these chemicals indicating low level contamination throughout the area. The degree of water/suspended sediment partitioning of the chemicals (Kp) was studied. Kp values for the individual chemicals changed in a manner consistent with changes in their physical-chemical properties.

Polymer-Graphene Nanoassemblies and their Applications in Cancer Theranostics

2020 ◽  
Vol 20 (11) ◽  
pp. 1340-1351 ◽  
Author(s):  
Ponnurengam M. Sivakumar ◽  
Matin Islami ◽  
Ali Zarrabi ◽  
Arezoo Khosravi ◽  
Shohreh Peimanfard
Keyword(s):  
Mechanical Stability ◽  
Chemical Properties ◽  
The Other ◽  
Hydrophilic Polymer ◽  
Two Dimensional ◽  
Normal Tissues ◽  
Physical Chemical ◽  
Anti Cancer ◽  
Good Biocompatibility ◽  
Cancer Theranostics

Background and objective: Graphene-based nanomaterials have received increasing attention due to their unique physical-chemical properties including two-dimensional planar structure, large surface area, chemical and mechanical stability, superconductivity and good biocompatibility. On the other hand, graphene-based nanomaterials have been explored as theranostics agents, the combination of therapeutics and diagnostics. In recent years, grafting hydrophilic polymer moieties have been introduced as an efficient approach to improve the properties of graphene-based nanomaterials and obtain new nanoassemblies for cancer therapy. Methods and results: This review would illustrate biodistribution, cellular uptake and toxicity of polymergraphene nanoassemblies and summarize part of successes achieved in cancer treatment using such nanoassemblies. Conclusion: The observations showed successful targeting functionality of the polymer-GO conjugations and demonstrated a reduction of the side effects of anti-cancer drugs for normal tissues.

scholarly journals Shellfish Chitosan Potential in Wine Clarification

2021 ◽  
Vol 11 (10) ◽  
pp. 4417
Author(s):  
Veronica Vendramin ◽  
Gaia Spinato ◽  
Simone Vincenzi
Keyword(s):  
Molecular Structure ◽  
Chemical Properties ◽  
Allergic Reactions ◽  
Chitin Content ◽  
Deacetylation Degree ◽  
Physical Chemical ◽  
Similar Chemical ◽  
Fungal Chitosan ◽  
Significant Difference ◽  
Fish Industry

Chitosan is a chitin-derived fiber, extracted from the shellfish shells, a by-product of the fish industry, or from fungi grown in bioreactors. In oenology, it is used for the control of Brettanomyces spp., for the prevention of ferric, copper, and protein casse and for clarification. The International Organisation of Vine and Wine established the exclusive utilization of fungal chitosan to avoid the eventuality of allergic reactions. This work focuses on the differences between two chitosan categories, fungal and animal chitosan, characterizing several samples in terms of chitin content and degree of deacetylation. In addition, different acids were used to dissolve chitosans, and their effect on viscosity and on the efficacy in wine clarification were observed. The results demonstrated that even if fungal and animal chitosans shared similar chemical properties (deacetylation degree and chitin content), they showed different viscosity depending on their molecular weight but also on the acid used to dissolve them. A significant difference was discovered on their fining properties, as animal chitosans showed a faster and greater sedimentation compared to the fungal ones, independently from the acid used for their dissolution. This suggests that physical–chemical differences in the molecular structure occur between the two chitosan categories and that this significantly affects their technologic (oenological) properties.

scholarly journals Electrospinning: A promising technique for drug delivery systems

2020 ◽  
Vol 59 (1) ◽  
pp. 441-454
Author(s):  
Carlos A. Martínez-Pérez
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Chemical Properties ◽  
Delivery Systems ◽  
Extrinsic Factor ◽  
Promising Technique ◽  
Physical Chemical ◽  
Set Up ◽  
Final System ◽  
Intense Research

AbstractIn the last years, electrospinning has become a technique of intense research to design and fabricate drug delivery systems (DDS), during this time a vast variety of DDS with mainly electrospun polymers and many different active ingredient(s) have been developed, many intrinsic and extrinsic factor have influence in the final system, there are those that can be attributed to the equipment set up and that to the physical-chemical properties of the used materials in the fabrication of DDS. After all, this intense research has generated a great amount of DDS loaded with one or more drugs. In this manuscript a review with the highlights of different kind of systems for drug delivery systems is presented, it includes the basic concepts of electrospinning, types of equipment set up, polymer/drug systems, limitations and challenges that need to be overcome for clinical applications.

Variability in soil physical–chemical properties along the root-explored profile in deep Oxisols of commercial eucalypt plantations

2021 ◽  
Vol 494 ◽  
pp. 119334
Author(s):  
Vinicius Evangelista Silva ◽  
Thiago Assis Rodrigues Nogueira ◽  
Cassio Hamilton Abreu-Junior ◽  
Arun Dilipkumar Jani ◽  
Salatier Buzetti ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Physical Chemical ◽  
Eucalypt Plantations

scholarly journals Insights in Behavior of Variably Formulated Alginate-Based Microcapsules for Cell Transplantation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Pia Montanucci ◽  
Silvia Terenzi ◽  
Claudio Santi ◽  
Ilaria Pennoni ◽  
Vittorio Bini ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Chemical Properties ◽  
Live Cells ◽  
High Performing ◽  
Physical Chemical ◽  
Degenerative Disorders ◽  
Selection Of ◽  
Better Than

Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M) enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation,in vitroandin vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.

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