Resin Deposits Research Articles

The conductive network optimization of composite graphite plates and its morphological analysis

The improvement of the conductivity and mechanical properties of composite graphite bipolar plates is critical for the performance optimization of proton exchange membrane fuel cells (PEMFC). However, it is difficult to achieve the balance of the conductivity and mechanical properties. An important element is that the resin deposits between graphite layers, resulting in weakened interconnection between the graphite layers, and this structure feature is directly related to the graphite and resin mixing process. In this study, a continuous conductive network was established to optimize the performance of composite graphite plates by developing the infiltration methods, which involved graphite plates preforming and resin infiltration (FGP-I). The conductive network was constructed preferentially through the preforming of graphite plates, which decreased the adverse effects of resin on the graphite connection during the mixing process. The conductivity of FGP-I was 322.64 S/cm at a resin content of 25 wt%, which was higher than that of the composite graphite plate made from the mixture of graphite and resin (FGP-M). The flexural strength of FGP-I was 86.95 MPa, higher than 57.97 MPa for FGP-M and 22.66 MPa for the flexible graphite infiltrated plates. And its helium permeability was 1.1*10-6 cm3·cm−2·s−1. The cross-section analysis and the density measurement confirmed that FGP-I possessed a more sufficient graphite conductive network and less structural defect, which were crucial factors to improve the composite plate performance. FGP-I was a viable candidate for composite bipolar plate preparation because the preparation method was straightforward and favorable to the balanced improvement of electrical conductivity and mechanical properties.

A Preliminary Study of Chemical Profiles of Honey, Cerumen, and Propolis of the African Stingless Bee Meliponula ferruginea.

Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Meliponula ferruginea from Tanzania. The honey of M. ferruginea was profiled by NMR and indicated different long-term stability from Apis mellifera European (Bulgarian) honey. It differed significantly in sugar and organic acids content and had a very high amount of the disaccharide trehalulose, known for its bioactivities. We suggested trehalulose to be a potential marker for African stingless bee honey analogously to the recent proposal for Meliponini honey from Asia, South America, and Australia and demonstrated its easy discrimination by 13C NMR. Propolis and cerumen were studied by GC-MS (gas chromatography-mass spectometry). The samples contained mainly terpenoids (di-and triterpenes) but demonstrated qualitative and quantitative differences. This fact was an indication that possibly M. ferruginea has no strict preferences for resins used to construct and protect their nests. The antimicrobial and anti-quorum sensing properties of the two materials were also tested. These first results demonstrated that the honey, cerumen, and propolis of African stingless bees were rich in biologically active substances and deserved further research.

Agarotetrol in agarwood: its use in evaluation of agarwood quality.

Agarwood, which is used as medicine and incense, contains sesquiterpenes and chromones. Agarotetrol is a chromone derivative found in high concentrations in the water-extract fraction of agarwood and thus may be present in pharmaceutical products made from decoctions of agarwood. Agarotetrol has been reported to be present at the early stages of cell death in calli. We therefore examined the presence of agarotetrol in medical- and incense-grade agarwood, in agarwood-source plants lacking resin deposits, and in artificially made agarwood. Agarotetrol appeared as a large peak in the HPLC chromatograms of all samples of medical-grade and artificially made agarwood, and in most incense-grade agarwood samples. In contrast, agarwood samples lacking resin deposits did not contain agarotetrol. These results show that agarotetrol is characteristic of resin formation. Agarotetrol was also detected in decoctions of agarwood. A newly developed TLC method for the detection of agarotetrol in agarwood is described.

Morphoanatomical and histochemical characterization of Larrea species from Northwestern of Argentina

Larrea divaricata Cav., L. cuneifolia Cav. and L. nitida Cav., Zygophyllaceae, are evergreen xerophytic shrubs occurring in Northwestern Argentina used in traditional medicine. The aim of this work was to characterize the morphology, anatomy and histochemistry of the vegetative organs of three Larrea species by light and scanning electron microscopy in order to provide supporting data for their correct identification and to determine the site of synthesis and accumulation of its main active compounds. The shape, number and percentage of coalescence of leaflets, presence or absence of mucrones and rachis and the shape of the stipules represented the main botanical differences between the studied Larrea species. Anatomically three species presented amphystomatic leaves, with thick resinous slightly striated cuticle with resinous deposits, polygonal epidermal cells with straight anticlinal walls, ciclocytic, brachy-paracytic and paracytic stomatal types, non-glandular trichomes and isolateral mesophyll. The position and abundance of the sclerenchyma at the mid vein and petiole transection allows the differentiation of the three species, been more abundant in L. cuneifolia. Secondary phloem and parenchyma cells presented abundant calcium oxalate druses and solitary rhomboidal crystals. Epidermal cells and cuticle layer of leaflets and stipules of the three species presented amber resin deposits and content which stained positively for polysaccharides, phenolic compounds, flavonoids and tannins, while mesophyll palisade cells showed small refracting droplets stained positively for lipophilic substances.

Production and preservation of resins-past and present.

Amber is fossilised plant resin. It can be used to provide insights into the terrestrial conditions at the time the original resin was exuded. Amber research thus can inform many aspects of palaeontology, from the recovery and description of enclosed fossil organisms (biological inclusions) to attempts at reconstruction of past climates and environments. Here we focus on the resin itself, the conditions under which it may have been exuded, and its potential path to fossilisation, rather than on enclosed fossils. It is noteworthy that not all plants produce resin, and that not all resins can (nor do) become amber. Given the recent upsurge in the number of amber deposits described, it is time to re-examine ambers from a botanical perspective. Here we summarise the state of knowledge about resin production in modern ecosystems, and review the biological and ecological aspects of resin production in plants. We also present new observations on conifer-derived resin exudation, with a particular focus on araucarian conifer trees. We suggest that besides disease, insect attacks and traumatic wounding from fires and storms, other factors such as tree architecture and local soil conditions are significant in creating and preserving resin outpourings. We also examine the transformation of resin into amber (maturation), focusing on geological aspects of amber deposit formation and preservation. We present new evidence that expands previous understanding of amber deposit formation. Specific geological conditions such as anoxic burial are essential in the creation of amber from resin deposits. We show that in the past, the production of large amounts of resin could have been linked to global climate changes and environmental disruption. We then highlight where the gaps in our knowledge still remain and potential future research directions.

Analytical characterization of “Indonesian amber” deposits: evidence of formation from volcanic activity

In this study the new mineralogical and geochemical evidence for the reason behind intensive resin production in trees and the formation of Indonesian resin deposits is presented. The analysed specimens of the “Indonesian amber” were subjected to the following comprehensive investigations: PAS, IR, RS XRD and SEM-EDS. It was found that the resins are originated due to intensive volcanic activity. Based on spectroscopic investigations, “Indonesian amber” was assigned to the glessite group. The investigations revealed that the traces of volcanic activity have survived in the studied specimens in their structure were the presence of tonstein and inorganic minerals are related to volcanic phenomena. “Floating” in opaque solid–foam resin indicated that resinous substance was strongly heated trough volcanic activity.

Species-level determination of closely related araucarian resins using FTIR spectroscopy and its implications for the provenance of New Zealand amber.

Some higher plants, both angiosperms and gymnosperms, can produce resins and some of these resins can polymerize and fossilize to form ambers. Various physical and chemical techniques have been used to identify and profile different plant resins and have then been applied to fossilized resins (ambers), to try to detect their parent plant affinities and understand the process of polymerization, with varying levels of success. Here we focus on resins produced from today’s most resinous conifer family, the Araucariaceae, which are thought to be the parent plants of some of the Southern Hemisphere’s fossil resin deposits. Fourier transform infrared (FTIR) spectra of the resins of closely related Araucariaceae species were examined to test whether they could be distinguished at genus and species level and whether the results could then be used to infer the parent plant of a New Zealand amber. The resin FTIR spectra are distinguishable from each other, and the three Araucaria species sampled produced similar FTIR spectra, to which Wollemia resin is most similar. Interspecific variability of the FTIR spectra is greatest in the three Agathis species tested. The New Zealand amber sample is similar in key shared features with the resin samples, but it does differ from the extant resin samples in key distinguishing features, nonetheless it is most similar to the resin of Agathis australis in this dataset. However on comparison with previously published FTIR spectra of similar aged amber and older (Eocene) resinites both found in coals from New Zealand and fresh Agathis australis resin, our amber has some features that imply a relatively immature resin, which was not expected from an amber of the Miocene age.

Возможные методы и пути утилизации отходов нефтедобывающей отрасли (на примере асфальтосмолопарафинистых отложений)

Возможные методы и пути утилизации отходов нефтедобывающей отрасли (на примере асфальтосмолопарафинистых отложений)

Анализ условий образования и методы борьбы с асфальтеносмолопарафиновыми отложениями в скважинах при добыче нефти на месторождениях Верхнего Прикамья

Анализ условий образования и методы борьбы с асфальтеносмолопарафиновыми отложениями в скважинах при добыче нефти на месторождениях Верхнего Прикамья

The Application of a New Association Equation of State (AEOS) for Prediction of Asphaltenes and Resins Deposition During CO2 Gas Injection

Asphaltene deposition is a serious problem that can cause fouling in the reservoir, well, pipeline, and the oil production and processing facilities. An association equation of state (AEOS) is one of the most useful models used to predict asphaltene phase behavior and asphaltene deposition conditions. For an AEOS, it is assumed that the total compressibility factor consists of physical and chemical parts. The authors apply the conventional form of compressibility factor developed by G. Soave (1972) to the physical compressibility factor. However, for the chemical compressibility factor a new form is proposed. The total compressibility factor obtained is then used to calculate the asphaltene and resin deposits. The amounts of deposited asphaltenes calculated through the proposed model along with the experimental results are used to calculate resin deposit. A comparison with the experimental results shows that the new proposed model can be used to predict the amounts of deposited resins and asphaltenes within an acceptable range of accuracy.

Variation in the Deterioration of Fossil Resins and Implications for the Conservation of Fossils in Amber

The deterioration of fossil resins (crazing, cracking, and darkening) was investigated by comparing the effects of one year of accelerated aging—specifically intensive exposure to light, heat, and fluctuating humidity, both individually and in combination—on samples from several natural resin deposits. These included two Cretaceous ambers (from Myanmar [Burma] and central New Jersey), two Tertiary ambers (from the Baltic and the Dominican Republic), and Holocene copal from Zanzibar. The five resins were chosen for their disparate ages and botanical origins (and thus chemical and physical properties), as well as their paleontological significance. In all cases, pronounced deterioration occurred under combined exposure to light and fluctuating humidity, based on surface crazing and a decrease in absorbance of light in the UV region (360–400 nm). While crazing did not visibly occur in cases of fluctuating humidity in dark conditions, or UV exposure alone, spectrophotometric evidence indicates that some deterioration did take place. Yellowing after exposure to elevated temperatures occurred in all samples tested, with the exception of Burmese amber. All four true ambers exhibited a decrease in UV absorbance after exposure to heat (while copal actually showed an increase). The samples from the five deposits represent three chemical subclasses of fossil resins, and each of the resins reacted differently to the various aging conditions, with New Jersey amber particularly unstable. Based on these results, amber collections should be stored in an environment with stable humidity, relatively low heat, and minimal exposure to light. Anoxic sealing and storage, and particularly embedding amber samples in a high-grade epoxy, may be beneficial, and further investigation is indicated.

First record of the family Belidae (Insecta, Coleoptera) in amber. New genus and species from the uppermost Albian amber of France

Until now, fossil weevils of the family Belidae were unknown from fossil resin deposits. In this article, Gratshevbelus erici n. gen., n. sp. is described a from the Lower Cretaceous (uppermost Albian) amber deposits of southwestern France. Recent members of this family are present only in the southern hemisphere, therefore this new finding in northern deposits helps to better understand the first stages of the radiation of this group during the Late Mesozoic.

Long-term impact of acid resin waste deposits on soil quality of forest areas I. Contaminants and abiotic properties

Acid resins are residues characterised by elevated concentrations of hydrocarbons and trace elements, which were produced by mineral oil industries in Central Europe during the first half of the last century. Due to the lack of environmental legislation at that time, these wastes were dumped into excavated ponds in public areas without further protection. In this work, the long-term effects of such resin deposits on soil quality of two forest areas (Bayern, Germany) were assessed. We evaluated the distribution and accumulation of contaminants in the surroundings of the deposits, where the waste was disposed of about 60 years ago. General soil chemical properties such as pH, C, N and P content were also investigated. Chemical analysis of resin waste from the deposits revealed large amounts of potential contaminants such as hydrocarbons (93 g kg − 1 ), As (63 mg kg − 1 ), Cd (24 mg kg − 1 ), Cu (1835 mg kg − 1 ), Pb (8100 mg kg − 1 ) and Zn (873 mg kg − 1 ). Due to the location of the deposits on a hillside and the lack of adequate isolation, contaminants have been released downhill despite the solid nature of the waste. Five zones were investigated in each site: the deposit, three affected zones along the plume of contamination and a control zone. In affected zones, contaminants were 2 to 350 times higher than background levels depending on the site. In many cases, contaminants exceeded the German environmental guidelines for the soil–groundwater path and action levels based on extractable concentrations. Resin contamination yielded larger total C/total N ratios in affected zones, but no clear effect was observed on absolute C, N and P concentrations. In general, no major acidification effect was reported in affected zones.

Long-term impact of acid resin waste deposits on soil quality of forest areas II. Biological indicators

In this study, we evaluated the effects of two acid resin deposits on the soil microbiota of forest areas by means of biomass, microbial activity-related estimations and simple biological ratios. The determinations carried out included: total DNA yield, basal respiration, intracellular enzyme activities (dehydrogenase and catalase) and extracellular enzyme activities involved in the cycles of C (β-glucosidase and chitinase), N (protease) and P (acid-phosphatase). The calculated ratios were: total DNA/total N; basal respiration/total DNA; dehydrogenase/total DNA and catalase/total DNA. Total DNA yield was used to estimate soil microbial biomass. Results showed that microbial biomass and activity were severely inhibited in the deposits, whilst resin effects on contaminated zones were variable and site-dependant. Correlation analysis showed no clear effect of contaminants on biomass and activities outside the deposits, but a strong interdependence with natural organic matter related parameters such as total N. In contrast, by using simple ratios we could detect more stressful conditions in terms of organic matter turnover and basal metabolism in contaminated areas compared to their uncontaminated counterparts. These results stress that developed ecosystems such as forests can buffer the effects of pollutants and preserve high functionality via natural attenuation mechanisms, but also that acid resins can be toxic to biological targets negatively affecting soil dynamics. Acid resin deposits can therefore act as contaminant sources adversely altering soil processes and reducing the environmental quality of affected areas despite the solid nature of these wastes.

Comparative Anatomy of the Wood of Abies Pinsapo and Its two Moroccan Varieties

This study describes the structure of the wood of Abies pinsapo from samples taken from its three natural distribution areas in the Iberian Peninsula (Sierra de Grazalema, Sierra de las Nieves and Sierra Bermeja) and compares them with the varieties from the north of Africa, Abies pinsapo var. marocana from the Talassemtane mountains and A. pinsapo var. tazaotana from the Tazaout mountains. All the samples were collected in their regions of provenance. To put the results into perspective, a comparison was also made with the wood of Abies alba and A. numidica. The wood of the Iberian A. pinsapo and of its two varieties from the Rif mountains in Morocco is anatomically similar, and there are no qualitative differences that enable the wood to be differentiated except for the presence of resin deposits in the tracheids adjacent to the rays in the samples from Grazalema. Quantitatively, for tracheid diameter and tracheid length there are statistically significantly differences (p<0.05) between those of Spanish provenance and the Moroccan varieties, but for tracheid pit diameter, largest diameter of cross-field pits and tall ray frequency the samples from Sierra Bermeja have more in common with the African samples.

Morphological Characteristics of Asbestos Fibers Released During Grinding and Drilling of Friction Products

There has been considerable interest during the past 30 years regarding the potential for exposure to asbestos fibers generated during asbestos-containing automobile and light-duty truck brake replacement and repair operations. Less attention has been directed to asbestos fiber exposures resulting from servicing of brakes on heavy-duty trucks and other machinery. Potential for the generation of respirable fibers as a result of using a rotary bench grinder and the drilling of asbestos-containing friction pads was investigated to assess the characteristics of the fibers generated from these procedures. The data from the grinding process revealed that this material was either resin matrix or fibers bound to the resin matrix. Fibers generated from the drilling procedure revealed morphology consistent with chrysotile asbestos. In each case, nonfibrous materials remained bound to the fibers released from these processes. These fibers had resin deposits attached. This investigation offers evidence that drilling and grinding of brake pads generates fibers that, for the most part, remain bound to the underlying matrix, suggesting that grinding and drilling may not pose an important source of exposure to respirable asbestos fibers.

Morphological characteristics of asbestos fibers released during grinding and drilling of friction products.

There has been considerable interest during the past 30 years regarding the potential for exposure to asbestos fibers generated during asbestos-containing automobile and light-duty truck brake replacement and repair operations. Less attention has been directed to asbestos fiber exposures resulting from servicing of brakes on heavy-duty trucks and other machinery. Potential for the generation of respirable fibers as a result of using a rotary bench grinder and the drilling of asbestos-containing friction pads was investigated to assess the characteristics of the fibers generated from these procedures. The data from the grinding process revealed that this material was either resin matrix or fibers bound to the resin matrix. Fibers generated from the drilling procedure revealed morphology consistent with chrysotile asbestos. In each case, nonfibrous materials remained bound to the fibers released from these processes. These fibers had resin deposits attached. This investigation offers evidence that drilling and grinding of brake pads generates fibers that, for the most part, remain bound to the underlying matrix, suggesting that grinding and drilling may not pose an important source of exposure to respirable asbestos fibers.

Consolidant Distribution in Deteriorated Wood Treated With Soluble Resins

Scanning electron microscopy was used to study the distribution of synthetic resin consolidants after treatment of deteriorated wood samples by vacuum impregnation. These resins included Butvar B98, Acryloid B72, and Butvar B90. After the samples had been completely saturated with consolidant, evidence of resin could be found throughout cross sections taken from them, although examination of the samples showed that the resin was not uniformly distributed. Most strikingly, some tracheids could be observed to have heavy deposits of resin, which in some cases completely filled the cell lumen, while adjacent tracheids contained litde or no resin. The percentage of earlywood tracheids with visible resin deposits in a given sample area was then used as an indicator of resin content. Results showed that there was greater concentration of resin in the surface layers of radial or tangential faces than in the specimen core, as well as a tendency toward increasing concentration toward the end surfaces.

Consolidant Distribution in Deteriorated Wood Treated with Soluble Resins

Scanning electron microscopy was used to study the distribution of synthetic resin consolidants after treatment of deteriorated wood samples by vacuum impregnation. These resins included Butvar B98, Acryloid B72, and Butvar B90. After the samples had been completely saturated with consolidant, evidence of resin could be found throughout cross sections taken from them, although examination of the samples showed that the resin was not uniformly distributed. Most strikingly, some tracheids could be observed to have heavy deposits of resin, which in some cases completely filled the cell lumen, while adjacent tracheids contained litde or no resin. The percentage of earlywood tracheids with visible resin deposits in a given sample area was then used as an indicator of resin content. Results showed that there was greater concentration of resin in the surface layers of radial or tangential faces than in the specimen core, as well as a tendency toward increasing concentration toward the end surfaces.

The basic principles of electrophoretic paint deposition and its application to the development of coating systems for metal powders on metal substrates for subsequent diffusion treatment

Electrophoretic coating is analogous to electroplating in that a voltage is applied across electrodes in a bath and insoluble solids are deposited to achieve a coating. However, in the case of electrophoretic coating the electrode coated is usually the anode, although cathodic systems have recently been developed. The anodic system dates back to the 1950s and is currently in use on a large scale in the motor industry for paint application because of its speed, the evenness of coating and the ease of draining. The system works by using water-soluble resins solubilized at pH 7.6 – 8.4 with organic amines. For paint systems pigments and extenders are also added. The paint deposition on the anode is achieved by using a high voltage (50 – 300 V) low current (0.3 – 0.5 A dm −2) d.c. supply. The resin macro-anions are attracted towards the anode by the steep voltage gradient close to the anode, i.e. electrophoresis. At the same time counterflow of the aqueous phase take place, i.e. electroendosmosis. This, together with the build-up of hydrogen ions, also near the anode, which gives an acidified layer, causes the resin to lose solubility and to coagulate on the anode. Where resin deposits it forms a resistive layer so that further deposition occurs at extremities; this is responsible for the high throwing power of the system and the evenness of the coating thickness. Pigment is deposited in a similar fashion since the pigment itself is coated with resin macro-ions. The system was adapted for the deposition of aluminium powder of 6 μm particle size onto Nimonic substrates and turbine blades for the purpose of providing a coating which, after diffusion treatment, was capable of providing a nickel aluminide layer for high temperature oxidation resistance at about 1000 °C. The main problems with the electrophoretic