Utilization of tyre rubber hybrid with ceramic and wood for impact energy absorption application

The used tyre rubber, scrap ceramic tiles and wood dust are largely dumped into landfills, which create environmental pollution to the surrounding. The recycling of tyre rubber is very limited, but it has good property to absorb the impact energy. Hence, these materials are used to prepare the composite in the present work. Composite materials were prepared by the resin transfer moulding method with different weight percentage of particles. The tensile, flexural and impact strength of composite specimens were compared with other combination of composites and also with the neat resin sample specimen. The tensile and flexural strength of composites were decreased with the addition of the rubber. But, the rubber particle with the ceramic in the resin matrix increases the impact strength of composite by 45.91% when compared with the neat resin sample. The addition of rubber enhances the impact strength of composite materials with all the combination of particles. The better distribution and good interfacial adhesion of particles with a resin matrix along the fractured surface were observed by the scanning electron microscope. And also, the nature of failure was identified by morphological studies.

Volatile Compounds in Oleo-gum Resin of Socotran Species of Burseraceae

Socotra Island is well known for its high rate of plant species endemism and having the highest concentration of frankincense species in the world. Thirteen species in Burseraceae occur on the island, of which 12 are endemic. A total of only four species from the island have had the chemical compositions of their resins published. Moreover, in general, most studies on chemical composition of frankincense and myrrh resins have analysed samples that were not freshly collected (including some of considerable age). Our study therefore aimed at analysing the volatile compound composition of all Socotran Burseraceae species, using fresh resin sample analysis. We found a total of 103 volatile compounds in all the species, with 53 of them fully identified, 27 of them partially determined and 23 still unidentified. These include four compounds (α‑fenchene, calarene, trans‑β‑farnesene, α‑elemene) newly reported from Boswellia and two (phytol and ledene) newly reported from Commiphora. Our results suggested the huge potential to find new chemical compounds among endemic Burseracean species.

Investigation of electroless nickel plating on rapid prototyping material of acrylic resin

Purpose – This paper aims to investigate the layer of material deposited on a sample of acrylic resin by electroless nickel plating process. Acrylic resin is a popular material in rapid prototyping (RP) which uses the additive manufacturing technique to build prototypes for visual inspection, assembly, etc. Metallization of the RP materials can extend application envelop of RP techniques, as they can be used in decorative or functional applications. Design/methodology/approach – Unlike electroless nickel plating on a metal substrate, the plating process for an acrylic resin substrate is different, as there is no metal ion for the auto-catalytic electroless reaction. Pre-treatment processes are performed on an acrylic resin sample to initiate electroless nickel plating. The morphology, chemical composition and structure of the layer deposited on the sample are examined using scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Findings – The investigation shows that a nickel phosphorous alloy layer is plated on to the substrate surface of the acrylic resin sample. Originality/value – Plating a layer of nickel phosphorous alloy layer on an acrylic resin RP material can widen the application of RP technology. An application of nickel plated acrylic resin sample to rapid tooling for low-volume production plastic parts is presented.

The Effect of Mechanical Stress and Surface Tracking of 22 kV Cable Spacer

Surface tracking is one of the causes that degraded the property of cable spacer. This research investigates about the mechanical stress and surface tracking performance of 22 kV cable spacer. Sample were tested according to the surface tracking under IEC 60587 standard under modified condition by and addition of the mechanical weight on the surface of pure epoxy resin sample. The mechanical load use were 0 kg and increase from 5 kg until 15 kg. The results showed that mechanical stress has affected the surface degradation of an insulation performance when the mechanical load is increased combined with high electrical field.

The Moss Macromitrium Richardii (Orthotrichaceae) with Sporophyte and Calyptra Enclosed in Hymenaea Resin from the Dominican Republic

Dominican amber is an important source for Early Miocene bryophytes. We report the moss Macromitrium richardii Schwägr., an extant representative of the Orthotrichaceae, from the Dominican amber collection of the American Museum of Natural History. This species is currently a widespread Neotropical epiphyte. The specimen includes several gametophytes and sporophytes, and represents the first fossil record of Orthotrichaceae. Alongside the Macromitrium shoots we observed several fragments of the liverworts Cheilolejeunea antiqua and Frullania sp. The unusual thermal behavior of the resin sample initially led to doubts about the Miocene age of the specimen, but chemical analyses of the Hymenaea resin provides evidence that the specimen represents a highly oxidized sample of Miocene Dominican amber rather than an artificially thermally-treated subfossil resin (copal). Our inclusion demonstrates the exceptional preservation potential of tree resin, but our observations also suggest that provenance (including any possibility that a modern resin has been thermally treated to make it appear older) should be scrutinized when single pieces with atypical thermal behavior and exceptionally well-preserved extant morphotypes come to light.

Advances in a Bioprocess for the Treatment of Nuclear Waste: Spent Ionic Exchange Resins

ABSTRACTDevelopment of a bioprocess intended to achieve a volume reduction of spent resins (either from research and power reactors) is the main purpose of this research project. Search is constrained to microorganisms that exhibit radioresistance, and which can be cultured in a heavy metal environment with additives of nuclear reactor waters such as boron, lithium and gadolinium compounds.Bacteria adapted to a radioactive environment were obtained by treating a RA-3 Reactor spent ionic exchange resin sample (kept at Área de Gestión Ezeiza: AGE) with sterile water; microorganisms suspended were isolated, subject to purity controls and characterized.Experiments performed with these strains include:-Culture in a mineral-broth having polystyrene as source of both carbon and energy. The strain RMB 1200 gave the highest number of viable cells, then being tested with some aromatic compounds, and with some additives of nuclear reactor waters and other elements found in spent resins.-An anionic exchange resin sample was heated, yielding a chemical environment resembling to that of radiolysed resins, and then RMB 1200 strain was cultured with this solid.-A technique to stain polymers was developed in order to find morphological changes caused by microbiological activity. Microscopic examination of cultured polymer samples has been performed.Results obtained with RMB 1200 include metabolic capabilities to use aromatic carbon sources (benzoate, polyphenols), its growth with polystyrene and resin, and short-term tolerance to several xenobiotics assayed at higher concentration levels than the ones of spent resins.

Perubahan kekuatan impak resin akrilik polimerisasi panas dalam perendaman larutan cuka apel

Acrylic resin being has been used in dentistry since 1946. Apple vinegar solutioncurrently popular as healthy supplement drink. It consists of tanin (fenol), acid, andother subtances. Fenol and acid are able to chemically damage to acrylic resin. Thepurpose of this study was to investigate the impact strength of heat cured acrylic resinafter immersed in apple vinegar solution. This experiment was carried out on the heatcured acrylic resin sample of size 65 x 10 x 2.5 mm. The immersion periods variedfrom 45 minutes, 11 days, and 17 days. There were 42 samples, divided into 21samples for three treatment groups and 21 samples for three control groups. Theresult showed that there were significant differences of acrylic resin strength afterimmersion in apple vinegar at 45 minutes and 17 days. The conclusion was the longerimmersion time of acrylic resin in apple vinegar would reduce the impact strength.

Measurement of the optical density of packable composites: comparison between direct and indirect digital systems

The aim of this study was to measure the optical density of four packable composite resins with widths of 1, 2, 3 and 4 mm, by means of Digora® (direct) and DentScan DentView® (indirect) digital imaging systems, in order to compare both methods. Twenty acrylic plates, with the proposed thicknesses, were used, each one containing a sample of each resin. Each acrylic plate was radiographed three times, under a standardized technique. For the Digora® system, an optical plate was used under each resin sample, and, for the DentScan DentView® system, occlusal films were employed, totalizing 60 exposures for each system. Optical plates and films were scanned and three consecutive optical readouts were carried out, totalizing 1,440 readouts. The results were submitted to statistical analysis and revealed that the average optical density of the four resins always increased as thickness increased. Regarding the comparisons between the composite resins, in both analysis the resin with the greater optical density was SurefilTM followed by ProdigyTM Condensable, AlertTM and Solitaire®. The correlations between the results of Digora® and DentScan DentView® were significant for the different thicknesses and materials. The observed tendency is that as the values obtained with the Digora® system increase, so do the values obtained with DentScan DentView®. While thickness increased, the values of optical density in both Digora® and DentScan DentView® tended to approach each other. The Digora® system presented smaller amplitude between the results obtained in adjacent thicknesses.

Potassium Permanganate Staining Allows For The Visualization Of An Outer Surface Component Of Selected Ehrlichiae

The Ehrlichia spp. are tick-borne pathogens that infect leucocytes and erythrocytes of human beings and animals (1-4). Three ehrlichial organisms, E. chaffeensis, E. equi, HGE (human granulocytic ehrlichiosis agent, equivalent to E. phagocytophila and closely related to E. equi), and Anaplasmamarginale were studied with respect to their morphology after using a combined fixative/potassium permanganate staining protocol (5). Cell cultures infected with the respective organisms were fixed and treated as follows: Tissues were initially fixed with Karnovsky's fixative [glutaraldehydeparaformaldehyde, 2.5/4.0% respectively], containing 0.1% tannic acid, in a Sorenson's phosphate buffer with 0.1M sucrose. Post fixation with OsO4 or without it occurred in some samples. En bloc staining with 1% aqueous uranyl acetate was always done. Dehydration was in a graded ethanol series followed by embedding in Spurr's™ resin. Sample sections were stained for 30-60 minutes at RT with 1% potassium permanganate. These were then washed for 5-15 seconds with 0.025-0.05% sodium citrate, jet washed with dH20, dried and examined (6).