Littérature scientifique sur le sujet « Tyre compounding »

Epoxidized natural rubber (ENR) / silica (Si) organic-inorganic composites were prepared by using a sol-gel technique. The choice of ENR (50 mol % epoxidation level), as a matrix was made because of its polar nature which can interact with the silica. The processing of the masterbatch was carried out by sol-gel method at room temperature by dispersing the silica in the rubber and coagulated with steam bath. The performance of the composites was evaluated in this work for the viability of ENR/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. Silica was also efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers. Improvement in tensile strength over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the rubber phase.

For both environmental and economic reasons, there is a continuing broad-based interest in the recycling of scrap rubber and therefore in the development of recycling technologies. In the present work three different sizes of mechanically ground Indian crumb rubbers were used in a natural rubber (NR) based tyre tread cap compound. Varying doses of crumb rubber were used as an additional compounding ingredient. The minimum torque and Mooney viscosity values were marginally increased with increasing dose and mesh size of crumb rubber. In a Rubber Process Analyser (RPA) study, the Payne effect before curing was marginally higher for compounds containing crumb rubber, while, after curing a comparable Payne effect was observed with respect to the control compound without having crumb rubber. A marginal deterioration in tensile strength, fatigue to failure and abrasion properties was observed. At all levels of usage, the 100 mesh size ground crumb rubber retained the properties better than other lower mesh size crumb rubbers.

Since the introduction of the so-called Green Tyre concept, in the early 90ies, the use of silica as reinforcing fillers has spread and grown worldwide. The general advantages of silica as reinforcing filler over carbon black filler are better rolling resistance by achieving at least equal wet traction while tread wear should not be adversely affected. One way to obtain both low rolling resistance and high wet traction is indeed, to use precipitated silica together with solution polymers in tyre treads. The benefits of reinforcement by silane coupled silicas, in certain blends of solution styrene –butadiene rubber (SBR) and butadiene rubber (BR), were recognized by major tyre manufacturer. However, the use of silica compounds entails considerable disadvantages in terms of raw material costs and processability (before vulcanization). These difficulties include higher compound Mooney Viscosity (ML1+4) that increases upon storage, short scorch time and environmental problems related to alcohol evolution. The high viscosity and poor processability in silica filled rubber compounds are believed to be associated with silica reaggregation (self aggregation) after rubber compounding. The study has been made of the effect of increased mixing stage and dispersion agent in rubber on uncured properties of the Silica Filled Epoxidised Natural Rubber Compounds. In this experiment, two orders of mixing were considered (1) Two Stages Mixing and (2) Three Stages Mixing. Results showed that filler dispersion, Mooney Viscosity and Payne Effect was influenced by the degree of mixing. The incorporation of dispersion agents in the compounds also resultant in the similar manner. It is believed that the dispersion agent could coat the silica surfaces as they are being broken down during the mixing and then stabilize the dispersed structure by stearically preventing silica reagglomeration.

In recent years, the increasing concern on the toxicity of highly aromatic oils has been incentive to the development of rubber process oils (RPOs) which are more environmentally-friendly. Many alternative eco-friendly RPOs have been tested with the aims of selecting the most suitable replacement for these highly aromatic oils. As a consequence, in order to achieve both environmental friendliness and effective rubber compounding, the aromatic content in RPOs must be optimised. In the present study, the experiments have been carried out to investigate the effects of aromatic and polycyclic aromatic compounds (PCAs) contents in RPOs on processability and mechanical properties of styrene butadiene rubber (SBR) compounds and vulcanisates. Results obtained suggest that the presence of RPOs leads to a decreased compound viscosity, and thus an enhanced processability. By incorporating the RPOs into SBR compounds, some mechanical properties including elongation at break and tear strength of cured SBR can be improved, particularly for the RPOs with high aromatic content. It is believed to be attributed to the increased compatibility between RPOs and SBR matrix. Nevertheless, the aromatic and PCA contents play little or insignificant role on the crosslink density and bulk viscosity of rubber compounds as well as hardness and compression set of vulcanisates.

Abstract In order to improve the quality of truck retreaded tyres, the cushion gum (CG) plays an important role as an adhesion medium to bond the carcass of the new tread to the worn old tyre. This study investigates the effect of natural rubber types such as reclaimed skimmed latex (RSL), ribbed smoke sheet (RSS), chloroprene (CR) and RSS added 10 phr of carbon black (CB) towards its CG performance in cold cure systems. The CG was compounded based on ASTM D3182 with 10 phr of Cumaroun Resin, 5 phr of Calcium Silicate, and other chemicals. The 4 types of CG were tested its physical and tensile properties. To determine the curing time, the rheological was analysed. The results show that the addition of carbon black may improve physical and tensile properties, excluding the elongation at break. It is found that the curing time of cushion gum based on SL rubber has the shortest duration. Each CG was applied to retreat the same type of truck’s worn tyres (1000R20). After surface modification, 5 mm of CG was bonded new same carcass the old surface and continued by heating in the autoclave chamber for 3 hours with pressure at 2 atm. The results show that the adhesion strength of cushion gum based on RSL; RSS; CR; RSS/CB is as follows: 13.64; 8.21; 8.04; 8.01 kN/m respectively, while the adhesion strength of commercial cushion gum is 15,38 kN/m. The spectra FTIR of each cushion gum convince that the less dispersion matrix compared to commercial cushion gum. To sum up, the RSL-NR is the recommended polymer for cushion gum compounding. However, in order to improve its quality, it is suggested to do some pre-treatment and increase the number of tackifier and processing oil in the formulation

Agro-industrial waste has become a major environmental issue in most parts of the world. Rice husk is one of the major agricultural wastes especially in Asian countries. It is currently thrown away into landfills or rarely use as an alternative energy source, which in turn produce another waste, rice husk ash (RHA). Silica is the major component in well-burnt RHA. This work was aimed to evaluate the feasibility of utilizing silica extracted from RHA and another industrial waste, used tyre treads, with natural rubber to develop composite with enhanced mechanical properties especially for flooring products such as rugs, pavement blocks, door mats, etc. In this work extracted silica was characterized using Fourier-transform infrared spectroscopy, X-ray diffractometry (XRD), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy (SEM). The SEM images confirmed that the extracted silica is in the nanometer to sub-micrometer length scale in size. Further our results confirmed that extracted silica has comparable chemical composition and amorphous nature as commercially used silica in rubber compounding. Composites were first formulated using crumb rubber to identify the optimum crumb rubber loading. It is found that 25 phr of crumb rubber provides the optimal mechanical properties. Finally, extracted silica was incorporated to 25 phr crumb rubber loaded composite to further reinforcement. SEM images confirm that 10 phr of silica have enhanced matrix-filler interactions to produce continuous structure, which was not observed in crumb rubber loaded rubber composite.

For decades, carbon black is the most preferred reinforcing filler in rubber industry especially in tyre manufacturing. Carbon black which originated from crude oil is a non renewable source that may diminish over time. Therefore, an alternative from natural source is needed to replace carbon black as the reinforcing agent in rubber industries without so much affecting the physical and mechanical properties of the final products. Since bamboo is an abundant natural source in Malaysia and proved to be one of the strongest natural fibres comparable to other building materials like steel, concrete, and timber that have been subjected to lot of studies, bamboo seems to be the best alternative to replace carbon black in reinforcing rubber. Bamboo chips were first treated using alkalinisation method and dried before ground to 180-250μm to improve the interfacial adhesion with the rubber matrix. The bamboo fibres were then incorporated into rubber through compounding process at different loading. The cure characteristics of the composites were determined at 150oC using rheometer. The curing times were then used to vulcanise the rubber compounds using a hot press. The mechanical behaviour of the bamboo fibre filled natural rubber composite like tensile strength, elongation at break, and hardness are then evaluated by taking the optimum loading of carbon black as the comparison. The strength of the composite were decreased and become harder as the fibre loading were increased. The weak adhesion of fibres to rubber matrix and uneven particle size distribution of fibres contribute to the fracture of the composites. These can be observed through the surface morphological analysis of the composite by using scanning electron microscopy (SEM).

Abstract Purpose The evolution of sterile compounding in the context of hospital patient care, the evolution of related technology, past incidents of morbidity and mortality associated with preparations compounded in various settings, and efforts over the years to improve compounding practices are reviewed. Summary Tightened United States Pharmacopeial Convention standards (since 2004) for sterile compounding made it difficult for hospitals to achieve all of the sterile compounding necessary for patient care. Shortages of manufactured injections added to the need for compounding. Non-hospital-based compounding pharmacies increased sterile compounding to meet the needs. Gaps in federal and state laws and regulations about compounding pharmacies led to deficiencies in their regulation. Lapses in sterility led to injuries and deaths. Perspectives offered include potential actions, including changes in practitioner education, better surveillance of sterile compounding, regulatory reforms, reexamination of the causes of drug shortages, and the development of new technologies. Conclusion Over the years, there have been numerous exhortations for voluntary better performance in sterile compounding. In addition, professional leadership has been vigorous and extensive in the form of guidance, publications, education, enforceable standards, and development of various associations and organizations dealing with safe compounding practices. Yet problems continue to occur. We must engage in diligent learning from the injuries and tragedies that have occurred. Assuming that we are already doing all we can to avoid problems would be an abdication of the professional mission of pharmacists. It would be wrong thinking to assume that the recent problems in large-scale compounding pharmacies are the only problems that warrant attention. It is time for a systematic assessment of the nature and the dimensions of the problems in every type of setting where sterile compounding occurs. It also is time for some innovative thinking about ensuring safety in sterile compounding.

By the composing of the rotation movements with the concurrent instantaneous axes in a point, a rotation movement with the instantaneous axis passing through that point is obtained. The resultant instantaneous angular velocity is sum of the component angular velocity. As examples of the mechanical systems in which appear the concurrent rotation movements are: the pivot bearings of the radial-axial with balls type, the ball radial bearings and the planetary mechanisms with bevel gears which are used both as differential to automotives and as orientation mechanisms (wrist) on the industrial robots.

Background and Objectives: With the increased prevalence of patients with cancer, the demand for preparing cytotoxic drugs was increased by health-system pharmacists. To reduce the workload and contamination of work areas in pharmacies, compounding robots preparing cytotoxic drugs have been introduced, and the use of the robots has been expanded in recent years. As reports on the comprehensive and quantitative evaluation of compounding robots remain lacking, a systematic review and meta-analysis were conducted to provide descriptive and quantitative evaluations of the accuracy of preparing injectable cytotoxic drugs. Materials and Methods: A systematic review and meta-analysis were conducted using published studies up to 2020. To identify eligible studies, PubMed, EMBASE, and Cochrane Library were used. All studies reporting the outcomes relevant to drug-compounding robots such as accuracy, safety, and drug contamination were included. Outcomes from included studies were descriptively summarized. Drug contamination by the robot was quantitatively analyzed using the odds ratio (OR) with a 95% confidence interval (CI). The risk of bias was assessed using the Risk of Bias Assessment tool for Non-randomized Studies (RoBANS). Results: A total of 14 compounding robot studies were eligible for review and 4 studies were included in the meta-analysis. Robotic compounding showed failure rates of 0.9–16.75%, while the accuracy range was set at 5%. Two studies reported that robotic compounding needed more time than manual compounding, two reported that robotic compounding needed less time, and one just reported preparation time without a control group. In a meta-analysis regarding the contamination of the compounding area, manual compounding was associated with lower contamination, although the result was not statistically significant (OR 4.251, 95% CI 0.439–51.772). For the contamination of infusion bags, the robot was associated with lower contamination (OR 0.176, 95% CI 0.084–0.365). Conclusions: Robotic compounding showed better accuracy than manual compounding and, without control groups, showed a high accuracy rate and also reduced the risk of drug contamination and compounding workload. The preparation time of the robot was not consistent because the type of robot and introduced system were different. In conclusion, robotic compounding showed mixed results compared to the manual compounding of drugs, so the system should be introduced considering the risks and benefits of robots.

Una delle principali applicazioni in cui i polimeri elastomerici trovano impiego è come componente strutturale nella formulazione di mescole per pneumatici. Tuttavia, affinché il prodotto finale possa soddisfare gli standard di prestazione richiesti, è necessario introdurre nella matrice polimerica dei componenti (filler) inorganici (Silice e Carbon Black). Sotto questo profilo, la compatibilità tra la fase polimerica e inorganica è dunque un aspetto di cruciale importanza. In questo contesto si colloca il presente progetto di dottorato, che ha come obiettivo quello di sviluppare un’innovativa strategia per migliorare il composito finale attraverso l’introduzione di gruppi funzionali sulla matrice polimerica in grado di interagire con le componenti inorganiche presenti in una mescola. Come prima cosa sono state scandagliate le opportunità che la letteratura offriva per trovare una reattività in grado di interessare i legami insaturi presenti nella matrice polimerica. In particolare, sono state identificate tre possibili alternative:cicloaddizione 1,3-dipolare, reazioni di tipo Tiol-Ene e reazioni di tipo Alder-Ene. Dopo aver verificato pregi e difetti di ciascuna reattività, la più promettente si è rivelata essere quella basata su una reazione di tipo Alder-Ene, che prevede l’interazione tra un’olefina, recante idrogeni in posizione allilica, ed un enofilo elettron-povero. Il composto enofilo da noi utilizzato e studiato come sistema modello è stato il 4-phenyl-1,2,4-triazoline-3,5-dione (PhTAD). Questo sistema, una volta ancorato sul polimero, presenta un gruppo ammidico secondario libero, in grado di modificare localmente la polarità della matrice e, contemporaneamente, di interagire tramite legami ad idrogeno con i filler inorganici come la silice. L’attività di ricerca è stata dunque concentrata sulla modifica chimica, con PhTAD, di olefine commerciali. Tali polimeri modificati, con diverse quantità di funzionalizzante, sono stati quindi caratterizzati tramite un approccio multitecnica (DSC, TGA, FTIR e prove di swelling) ed in seguito introdotti in mescola. Le proprietà reologiche delle mescole ottenute sono state valutate sia con un reometro a disco oscillante (ODR) sia tramite analisi dinamico meccaniche a temperatura variabile (DMTA) ed analizzandone le curve di stress-strain. Si è quindi tentato di risolvere le criticità emerse nell’utilizzo di PhTAD come agente di funzionalizzazione. Innanzitutto, è stato necessario ottimizzarne la quantità introdotta in mescola arrivando, nel migliore dei casi, ad ottenere compositi in cui i valori di G’ fossero comparabili con gli standard di rifermento industriali, che si basano sull’utilizzo di agenti compatibilizzanti come il TESPT, con un contestuale leggero peggioramento dei valori come il tanδ o l’effetto Payne, indice di un’effettiva interazione tra la matrice polimerica funzionalizzata con le cariche di silice, seppur non ottimale. Inoltre, uno dei maggiori problemi intrinseci da risolvere nell’utilizzo di una molecola come il PhTAD, risiede nella sua alta reattività che rende impossibile operare in massa, direttamente sul polimero pristino. L’ultima parte del progetto è stata quindi dedicata alla sintesi di funzionalizzanti di natura simile, a base diazenica, ma meno reattivi, allo scopo di far avvenire la reazione sul polimero direttamente in fase di formulazione, alle temperature a cui vengono processate le mescole (≈140°C), svincolandosi così dalla difficoltà derivanti dell’operare in soluzione. In particolare,l’avvenuta funzionalizzazione di un sistema oligomerico modello con ethyl(anilinocarbonyl)diazenecarboxylate ha permesso di dimostrare la validità dell’idea di una funzionalizzazione in massa termicamente stimolata, aprendo alla possibilità di impiego di altri sistemi molecolari, modificabili appositamente per assolvere una funzione specifica all’interno della mescola.
One of the main applications in which elastomeric polymers are used is as a structural component in the formulation of tire compounds. However, to match the required performance standards for the final product, it is necessary to introduce inorganic components (fillers) (Silica and Carbon Black) into the polymer matrix. From this point of view, the compatibility between the polymeric and inorganic phases is, therefore, an aspect of crucial importance. In this context the present PhD project is set up, which aims to develop an innovative strategy to improve the final composite through the introduction of functional groups on the polymer matrix able to interact with the inorganic components present in a compound. First, the opportunities offered by the literature to find a reactivity able to affect the unsaturated bonds present in the polymer matrix were explored. In particular, three possible alternatives have been identified: 1) 1,3-dipolar cycloaddition 2) Tiol-Ene type reactions 3) Alder-Ene type reactions After having verified the strengths and weaknesses of each reactivity, the most promising one has been to be based on an Alder-Ene reaction, which involves the interaction between an olefin (bearing hydrogen in an allyl position) and an electron-poor enophile. The enophilic compound we studied as a model system was 4-phenyl-1,2,4-triazoline-3,5-dione (PhTAD). This system, once anchored on the polymer, has a secondary amide group, able to modify locally the polarity of the matrix and, at the same time, able to interact through hydrogen bonds with inorganic fillers such as silica. The research activity has been focused on the chemical modification, with PhTAD, of commercial unsaturated polymers. These modified polymers, with different amounts of functionalizer, were then characterized by a multitechnical approach (DSC, TGA, FT-IR and swelling tests) and subsequently introduced into the mixture. The rheological properties of the compounds obtained were evaluated both with an oscillating disk rheometer (ODR), and by dynamic mechanical analysis at variable temperatures (DMTA) and by analyzing stress-strain curves. Preliminary attempts have been performed to resolve the critical issues that emerged when using PhTAD as a functionalization agent. First, it was necessary to optimize the amount introduced into the mixture, arriving, at best, to obtain composites in which the values of the G' module were comparable with the industrial reference standards, which are based on the use of compatibilizing agents such as TESPT, with a slight contextual deterioration of the values such as tanδ or the Payne effect, indicating an effective interaction between the polymer matrix functionalized with silica fillers, even if not yet optimally. Moreover, one of the major intrinsic problems to be solved in the use of a molecule such as PhTAD lies in its high reactivity which makes it impossible to operate in bulk, directly on the pristine polymer. The last part of the project was then dedicated to the synthesis of functionalizers of a similar nature, based on diazenics, but less reactive, in order to make the reaction occur on the polymer directly in the formulation phase, at the temperatures normally used to process compounds (≈140 °C), thus avoiding the difficulty due to operating in solution. The successful functionalization of a model oligomeric system with ethyl (anilinocarbonyl) diazenecarboxylate has allowed to demonstrate the validity of the idea of a thermally stimulated mass functionalization, opening to the possibility of using other molecular systems, that can be tuned specifically to perform a specific function within the compound.

Gothic is rich in endocentric N+N compounds. Except for V+N, other kinds of nominal endocentrics are also plentiful. Less frequent are adjectival endocentrics. Most productive of the exocentric compounds is the adjectival type (bahuvrihis). Predominant among the synthetic type are those with -(j)an- and participial heads. Gothic has identificational compounds but possibly no dvandvas. These are difficult to identify due to uncertainties in the meaning of the constituents. Several compounding heads were grammaticalized as suffixes, most notably -laus (free from, deprived of) and -leiks ((a)like, -ly). A composition vowel is normal in endocentrics. Bahuvrihis with a non-n-stem adjectival first component have no juncture -a-, nor do compounds beginning with a P-word or indeclinable numeral. No compound types are shared exclusively by Gothic and North Germanic.

Abstract Elastomers comprise a subclass of polymers that display the ability to stretch and recover that is typical of a rubber band. This chapter describes the properties determined by tensile testing of elastomers and the factors influencing them, namely, structuring of the molecular matrix, compounding, specimen preparation, specimen type, vulcanization parameters, and temperature. The chapter also provides information on ASTM D 412, the most widely referenced standard for determining the tensile properties of elastomers.

This chapter focuses on Type 2 (lexical aspectual) compound verbs, which appear to occupy a unique position in the systems of V-V complexes in Asian languages because they make up lexical combinations with desemanticized verbs in V2. Based on diachronic data, it is suggested that this marked class of compound verbs arose in Late Middle or Early Modern Japanese via two paths: (i) reanalysis and lexicalization of aspectual auxiliary constructions in Old and Early Middle Japanese and (ii) constructionalization of a special compounding schema where V2 specifies the manner and other adverbial meanings of V1. The latter path is characterized by the desemanticization of V2s in Type 1 thematic compounds or by spontaneous coinage of new V2s with adverbial meanings. The multifaceted development of Type 2 compounds, which does not readily fit in with the standard view of item-by-item grammaticalization, presents a motivation for viewing grammaticalization as creation of a novel morphological construction.

The aim of this paper was to assess the influence of the modification of the surface of dolomite and kaolin with SiO2 and TiO2 precursors, on the block copolymer styrene-butadiene-styrene (SBS) type thermoplastic rubber properties. These composite materials were obtained by compounding SBS with various ratio of powders. Based on the SEM images it can conclude that the powders were homogenously dispersed in to the SBS matrix. The dolomite particles can be clearly identified in the SEM images as particles of 10 micrometers. The samples obtained with modified dolomite have similar morphology. The EDS elemental distribution confirming a good corroboration between the elements of the dolomite, kaolin and titanium or silicon elements. Based on the thermal analysis according to the residual mass, the presence of 20% mineral phase can be confirmed. According to the DSC curves a strong stabilization of the composite appears, because of the presence of the mineral component. According to the physical-mechanical data all the composite materials exhibit improved mechanical properties. Additionally, the modification of the kaolin and/or dolomite bring important improvements in mechanical properties. The samples 13 and 14 exhibit high tensile and tear strength. These composites can be used for various applications, such as, for instance, soles for firefighters' footwear.

In many industrial gas turbine compressor designs, the compressors later stage blade angles are reduced in a constant flow area section as a means to even out the per stage workload. Most compressors use NACA 65 series type airfoils, which are good for high subsonic and supersonic flow, but are poor for middle or low subsonic flows. The temperature increases as the compression ratio increases; which cause the Mach number to drop. With reduced blade cascade overlaps, a reduction in axial blade solidity results. The compounding effect of low solidity and a low Mach number can cut the stalling angle by several degrees. This recent study found that compressor stall more or less is linked to the change of moment coefficient Cm, rather than lift coefficient Cl. Designing the airfoil, by extending the constant moment coefficient to a higher angle of attack region can delay the trailing edge upper surface separation to a higher angle of attack, the main source of rotating stall. This separated flow exhibits itself more clearly on the moment coefficient, but is obscured by an increase in lift coefficient before “aerodynamic” stall. This new design is based on the second order derivative of the camber line, with a low drag symmetrical airfoil thickness. Numerical simulation of a single airfoil and cascade of the new airfoil is compared with other shapes. The results show that the trailing edge flow separation begins at a 9.5-degree angle of attack for the NACA 65 series airfoils. The NACA 0012 separation (i.e. change in Cm) starts at 5 degrees (total stall occurs at 11 degrees). The new airfoil CFS18-0010 exhibits no separation for a single airfoil of up to 12 degrees. The cascade results showed no flow separation up to an angle of 15 degrees, which is enough to eliminate most of the rotating stall.

Abstract ASME Code Section VIII Division 1 [1] provides rules for the shape of openings, size of openings, strength and design of openings, however, the existing rules do not provide any restrictions on the specific location of the nozzle on the dished head knuckle region. Many corporate guidelines/ user design requirements meant for pressure vessel design and specification suggest avoiding placement of any type of nozzle in the knuckle area of a dished head and generally state in their design specification to limit the placement of a nozzle including its reinforcement within the crown area. This applies to Torispherical and Ellipsoidal dished heads. Code [1] rule UG-37(a) provides the benefit in reinforcement by reducing the required thickness (tr) of the dished head when the nozzle is in the spherical portion of the dished head for the Ellipsoidal and Torispherical dished head. High stresses occur in the knuckle region of the dished head due to the edge bending effect caused as the cylinder and head try to deform in different directions. For various reasons the user design requirements insist on placing the nozzle in the knuckle region, further compounding the complexity of the stress pattern in the knuckle area. The work carried out in this paper was an attempt to check whether it is safe to locate a nozzle in the knuckle region of the dished head since the knuckle portion is generally subjected to higher stresses in comparison to the crown portion of a dished head and the Code [1] and [2] does not impose any restrictions for the placement of nozzles in the knuckle region. Also, in this paper an attempt was made to evaluate the induced stresses when equivalent sizes of nozzles are placed in the crown as well as the knuckle portion of the dished head.

The effect of directional orientation of Chopped steel wool fiber in a friction material matrix / Brake pads that influences Friction, Wear and Mechanical properties of the Brake pads have been evaluated in a phenolic resin-based asbestos-free semi-metallic friction material composition. </p><p>Brake pad compositions widely use chopped steel wool fibers having a nominal length of less than 10 mm; diameter of about 500 microns; carbon content between 0.05 – 0.15 % as reinforcement. During compounding and mixing of friction material formulation, chopped Steel wool fibers along with dozen other raw materials are mixed/homogenized using plough shear mixer resulting in the steel fibers dispersed and oriented randomly in different plan and direction in the mixture and so over the final brake pad matrix too. </p><p>Trials have been carried out in Fricmart’s prototype Lab to orient chopped steel wool fiber in an uni directional plan in various semi-metallic formulations and progress has been achieved only in a medium- steel brake pad formulation that contains about 25% chopped steel fibers. Fricmart’s S-428 grade Steel wool fiber conforming to the above said specification has been used in the experiments. Fibers were initially classified using a set of sieves to remove the fines having diameter and length less than 200 microns and 3 mm respectively to meet the desired loose density / bulk density limit of 0.55 – 0.70 gm/cc to support the process of orientation. Further, a brake pad model that has rectangular geometry ( Merc. W-123 Pad) with an area of about 50 sq. cm was chosen to conduct the trials and to support the process of orientation. Brake pads were molded using conventional compression molding process at temp. of 150 deg. C with specific pressure of 250 bar and 6 minutes curing followed by 4 hours step curing ( post-baking ) to max. temp. of 180 deg. C in an air oven . Preparation of Samples: Sample 1 -By employing bi-directional magnetic field coupled with other special charging chute and dispersing techniques, the desired orientation of chopped steel wool fiber that was targeted to be parallel to the sliding direction of the brake (pad) was achieved to a level of more than 90% evenly oriented throughout the layer and matrix of the brake pad. Fricmart’s PLM – Stereo Microscope surveillance facility is used to ascertain percentage orientation during trials. Sample - 2: Brake pads processed as above by “parallel orientation to sliding direction’’ have later been used to study the effect of “orientation in perpendicular to the sliding direction’’ just by “inverting the new sample” specimen at the time of testing. Sample - 3: One set of brake pads were processed as per industries standard using the same batch/composition of raw materials with a random distribution of chopped steel wool fiber under identical process condition without carrying out directional orientation. Testing & Evaluation:The samples were cut from the brake pad and tested in Chase Type Friction Tester as per SAE J661 – small sample testing and the following are the observations. Internal shear measured as per ISO 6311 of sample -1 was significantly higher than sample – 2 & least in the case of sample 3 Faster bedding or faster adaptability to the disc in case of the sample- 1. 80% bedding achieved within 10 minutes of burnishing as compared to 20 minutes in case of samples- 2 & 3. The coefficient of friction is also dependent on the fiber orientation and µ for the developed pad ranges between 0.35 and 0.40. Fade resistance for samples 1 & 2 is superior when compared to sample 3.</p><p>Further, it was observed that as temperature increases, initially there was abrasion/plowing and on a further rise in temperature, a transfer film was developed making the steady-state friction. The wear rates decreased if the sliding path/direction changes from parallel to the perpendicular direction. The worn surface morphology was studied using FESEM and found that wear resistance is found to relate to the stability of the developed film. Sample 1 with the fibers oriented parallel to the sliding direction exhibited smoother running whereas sample 2 created undesirable judder noise. Hence it can be concluded that the Orientation of fibers with respect to sliding direction is preferable to the randomly oriented fibers towards frictional characteristics.

Analysis of intersecting social inequalities is key to effective, inclusive interventions in crisis settings. Gender equality and social inclusion analytical frameworks provide key research questions and participatory methodologies which seek to understand: Who is excluded? How are they excluded? Why are they excluded? What can be done to address this and support greater inclusion? There is a focus on underlying power dynamics, drivers of marginalisation, and entry points for external support. This rapid review presents a summary of relevant analytical frameworks and good practice for analysing intersecting social inequalities in crisis settings. The focus is on how to undertake contextual analysis of the vulnerabilities and needs of people in crises that are shaped by overlapping and compounding social inequalities, arising from discrimination based on gender, age, disability, sexual orientation, gender identity and/or expression and sex characteristics, ethnicity and religion (among other identifiers). The review draws on and presents prior research that identified relevant analytical frameworks, learning and key resources on how to undertake this type of analysis, through a rapid literature search and input by key experts. It summarises a range of frameworks relevant for analysing intersecting social inequalities in crisis settings, developed for various development, humanitarian and peacebuilding objectives. It was harder to find published learning from undertaking this analysis that focuses specifically on crisis settings, but it was possible to draw findings from some individual case studies as well as relevant summaries of learning presented in the analytical frameworks and other guidance materials.