Brake friction composite materials: A review on classifications and influences of friction materials in braking performance with characterizations

2021 ◽  
pp. 135065012110640
Author(s):  
G. Sathyamoorthy ◽  
R. Vijay ◽  
D. Lenin Singaravelu
Keyword(s):  
Natural Products ◽  
Composite Materials ◽  
Basic Knowledge ◽  
Great Promise ◽  
Processing Methods ◽  
Friction Materials ◽  
Braking Performance ◽  
Toxic Materials ◽  
The Common

Brake friction materials play an important role in automobiles to reduce speed and to stop the vehicles. Advances in friction materials were updated to ensure effective performances in braking systems and to provide the maximum safety and comfort. Presently eco-friendly friction materials have been used as a replacement for conventional friction materials. Many synthetic and natural products were identified and claimed as better alternatives to banned toxic materials like asbestos and copper. Friction materials developed from natural products are eco-friendly and assure a great promise when applied in modern vehicles. To develop innovative formulations, basic knowledge of common ingredients and their effects in friction materials was needed. This review focuses mainly on providing detailed information about the common ingredients used, processing methods and the characteristics of brake friction materials.

Formal Total Syntheses of Crocacin A-D

2005 ◽  
Vol 70 (10) ◽  
pp. 1696-1708 ◽  
Author(s):  
Magnus Besev ◽  
Christof Brehm ◽  
Alois Fürstner
Keyword(s):  
Natural Products ◽  
Aldol Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
The Common ◽  
Selective Addition

A concise route to the common polyketide fragment5of crocacin A-D (1-4) is presented which has previously been converted into all members of this fungicidal and cytotoxic family of dipeptidic natural products by various means. Our synthesis features asyn-selective titanium aldol reaction controlled by a valinol-derived auxiliary, a zinc-mediated, palladium-catalyzedanti-selective addition of propargyl mesylate10to the chiral aldehyde9, as well as a comparison of palladium-catalyzed Stille and Suzuki cross-coupling reactions for the formation of the diene moiety of the target.

scholarly journals Effects of Alkyl-Substituted Polybenzoxazines on Tribological Properties of Non-Asbestos Composite Friction Materials

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 567
Author(s):  
Anun Wongpayakyotin ◽  
Chanchira Jubsilp ◽  
Sunan Tiptipakorn ◽  
Phattarin Mora ◽  
Christopher W. Bielawski ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Materials ◽  
Coefficient Of Friction ◽  
Aromatic Amines ◽  
Underlying Structure ◽  
Methyl Groups ◽  
Friction Materials ◽  
Wear Rates ◽  
Structure Properties ◽  
Crosslink Densities

A series of substituted polybenzoxazines was synthesized and studied as binders in non-asbestos friction composite materials. The structures of the polybenzoxazines were varied in a systemic fashion by increasing the number and position of pendant alkyl (methyl) groups and was accomplished using the respective aromatic amines during the polymer synthesis step. By investigating the key thermomechanical and tribological characteristics displayed by the composite materials, the underlying structure-properties relationships were deconvoluted. Composite friction materials with higher thermomechanical and wear resistance properties were obtained from polybenzoxazines with relatively high crosslink densities. In contrast, polybenzoxazines with relatively low crosslink densities afforded composite friction materials with an improved coefficient of friction values and specific wear rates.

Synthetic Strategies to Access Heteroatomic Spirocentres Embedded in Natural Products

Synthesis ◽  
2021 ◽  
Author(s):  
Michael P. Badart ◽  
Bill C. Hawkins
Keyword(s):  
Natural Products ◽  
Heterocyclic Compound ◽  
Chemical Space ◽  
Three Dimensional ◽  
Coupling Reactions ◽  
Conjugate Additions ◽  
Biological Targets ◽  
Compound Libraries ◽  
The Common ◽  
Significant Attention

AbstractThe spirocyclic motif is abundant in natural products and provides an ideal three-dimensional template to interact with biological targets. With significant attention historically expended on the synthesis of flat-heterocyclic compound libraries, methods to access the less-explored three-dimensional medicinal-chemical space will continue to increase in demand. Herein, we highlight by reaction class the common strategies used to construct the spirocyclic centres embedded in a series of well-studied natural products.1 Introduction2 Cycloadditions3 Palladium-Catalysed Coupling Reactions4 Conjugate Additions5 Imines, Aminals, and Hemiaminal Ethers6 Mannich-Type Reactions7 Oxidative Dearomatisation8 Alkylation9 Organometallic Additions10 Conclusions

Microorganisms in Bioflotation and Bioflocculation: Potential Application and Research Needs

2009 ◽  
Vol 71-73 ◽  
pp. 319-328 ◽  
Author(s):  
K. Hanumantha Rao ◽  
Annamaria Vilinska ◽  
I.V. Chernyshova
Keyword(s):  
Energy Charge ◽  
Surface Reactivity ◽  
Basic Knowledge ◽  
Primary Data ◽  
Great Promise ◽  
Mineral Surface ◽  
Processing Technologies ◽  
Ore Processing ◽  
Charge Potential ◽  
Mineral Beneficiation

Conventionally, physico-chemical methods are used in mineral processing for recovering value minerals from ores. The ageing of ore processing tailings and waste rocks, and mining tailings contamination by chemical reagents constitute a major threat to the environment. It is imperative to develop novel economically more efficient and environmentally benign methods of flotation and waste processing, exploiting the intriguing and exciting ability of bacteria to selectively modify the surface properties of solids. Microorganisms have not only facilitate hydrometallurgical leaching operations but have also show a great promise in mineral beneficiation processes such as flotation and flocculation. Several laboratory investigations revealed that microorganisms could function similar to traditional reagents. Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. The bio-modification of mineral surfaces involves the complex action of microorganism on the mineral surface. The manner, in which bacteria affect the surface reactivity and the mechanism of bacteria adsorption, is still unknown and accumulation of the primary data in this area is only starting. The bio-flotation and bio-flocculation processes concern the mineral response to the bacterium presence, which is essentially interplay between microorganism and the physicochemical properties of the mineral surface, such as the atomic and electronic structure, the net charge/potential, acid-base properties, and wettability of the surface. There is an urgent need for developing basic knowledge that would underpin biotechnological innovations in the natural resource (re)processing technologies that deliver competitive solutions.

A Review on Non-Asbestos Friction Materials: Material Composition and Manufacturing

2018 ◽  
Vol 1150 ◽  
pp. 22-42
Author(s):  
Dinesh Shinde ◽  
Kishore N. Mistry ◽  
Suyog Jhavar ◽  
Sunil Pathak
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Single Phase ◽  
Friction Material ◽  
Material Surface ◽  
Surface Wear ◽  
Friction Modifier ◽  
Friction Materials ◽  
Morphological Studies ◽  
The Impact

The peculiar feature of friction materials to absorb the kinetic energy of rotating wheels of an automobile to control the speed makes them remarkable in automobile field. The regulation of speed cannot be achieved with the use of single phase material as a friction material. Consequently, the friction material should be comprised of composite materials which consist of several ingredients. Incidentally, the friction materials were formulated with friction modifier, binders, fillers and reinforcements. Due to its pleasant physical properties, asbestos was being used as a filler. Past few decades, it is found that asbestos causes dangerous cancer to its inhaler, which provides a scope its replacement. Several attempts have been made to find an alternative to the hazardous asbestos. The efforts made by different researchers for the impact of every composition of composite friction material in the field are reviewed and studied for their effect on the properties of friction material. Surface morphological studies of different friction material are compared to interpret the concept of surface wear and its correlation with material properties.

scholarly journals The Review of Chemistry, Pharmacology and Processing Method of Rhubarb (Rheum species)

2019 ◽  
Vol 8 ◽  
Author(s):  
Jingwen He ◽  
Liang Wang ◽  
Hongxing Guo ◽  
Hui Zhao ◽  
Jiachen Sun
Keyword(s):  
Blood Circulation ◽  
Processing Method ◽  
The Body ◽  
Chemical Compositions ◽  
Pharmacological Activities ◽  
Processing Methods ◽  
Traditional Medicines ◽  
Toxic Materials ◽  
Different Types ◽  
Body Cooling

Rhubarb is one of the Chinese traditional medicines. About ninety-four compounds with five different types of skeletons (anthraquinone, anthrones, stilbenes, flavonoids and acylglucosides) have been isolated from rhubarb so far. These constituents are effective in purgative, clearing heat-fire, removing toxic materials from the body, cooling blood and promoting blood circulation. Recent studies have shown that the appropriate processing methods may directly impact on its nutraceutical activities and chemical compositions. Here, we summarize the update progress in the chemical compositions, pharmacological activities and processing methods of rhubarb.

Tribological performance characterization of brake friction materials: What test? What coefficient of friction?

2018 ◽  
Vol 233 (1) ◽  
pp. 214-226 ◽  
Author(s):  
Mohamed Kchaou ◽  
Amira Sellami ◽  
Jamal Fajoui ◽  
Recai Kus ◽  
Riadh Elleuch ◽  
...  
Keyword(s):  
Material Properties ◽  
Experimental Methods ◽  
Tribological Performance ◽  
Small Sample ◽  
Large Field ◽  
Friction Materials ◽  
Braking Performance ◽  
Specific Protocol ◽  
Reduced Scale

This article describes and explains the tribological tests and methods for the evaluation of the performance of the brake friction materials. It starts by discussing the particularities of these materials and the variation of characterization tests, which can experimentally simulate many aspects of brake situation but with a large field of tribo-test, from standard to specific protocol. Examples of preparation, procedures, instrumentation, and analysis results for the tribological aspect testing ranging from the scale of vehicle braking performance (by methods including inertia dynamometers, Krauss testing, friction assessment screening test, and Chase testing) to simplified test using reduced-scale prototypes for small-sample friction, are explained. A particular attention is attributed to the discussion of the viability of the friction coefficient report in relation to the material properties and brake compound performance. At the end of this article, the guarantee of the performance output or ranking evaluated by such experimental methods is discussed.

Endoscopic retrograde cholangio-pancreatography: a review for endoscopy nurses and assistants

2019 ◽  
Vol 17 (Sup8) ◽  
pp. S8-S14
Author(s):  
Muhammad Waqas Fazal ◽  
Maria Tan ◽  
Shyam Menon
Keyword(s):  
Bile Duct ◽  
Common Bile Duct ◽  
Pancreatic Duct ◽  
Clinical Outcomes ◽  
Endoscopic Retrograde Cholangiopancreatography ◽  
Patient Selection ◽  
Basic Knowledge ◽  
Endoscopic Retrograde ◽  
The Common

Endoscopic retrograde cholangiopancreatography (ERCP) facilitates endoscopic access to the common bile duct and pancreatic duct. It has become central to the management of a variety of benign and malignant pancreatobiliary disorders. ERCP remains a technically challenging procedure and patient selection and pre-assessment is critical to ensure good clinical outcomes. Staff assisting in ERCP should familiarise themselves with the underlying principles and basic knowledge pertaining to various aspects of ERCP.

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