Journal articles: 'Comparison of waxes'

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Wójcicka, Agnieszka. "Effect of epicuticular waxes from triticale on the feeding behaviour and mortality of the grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae)." Journal of Plant Protection Research 56, no. 1 (January 1, 2016): 39–44. http://dx.doi.org/10.1515/jppr-2016-0006.

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AbstractSurface waxes from wax-covered triticale plants (RAH 122) were sprayed on plants of the waxless genotype RAH 366 or the surface waxes were used to make artificial diet preparations. The results were significant increases in the mortality of apterous adults of the grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) at all concentrations tested in comparison with those aphids which fed on the control plants or aphids which were reared on the diets. In the choice tests, most aphids settled on plants without surface waxes or on diet preparations which did not have surface waxes (the controls). When the concentration of the surface waxes was increased on one of the plants or surface waxes were increased in the diet preparation, the number of wandering aphids increased. Those aphids which did not wander were mainly on the waxless control plants or on the waxless diet preparations. Aphids did settle on those plants or on the diet preparations which had 100 and 1,000 μg · g-1of surface wax. The aphids rarely settled on the diet preparations containing 10,000 μg ∙ g-1of surface waxes. From these observations it appears that surface waxes can act as a feeding deterrent. Since aphids on plants with surface waxes, or aphids which settled on diet preparations with surface waxes, started to die earlier than aphids fed only the control plants or the control diet preparations, it is possible that the surface waxes had a toxic effect that led to early mortality. Thus, it can be said that the surface waxes caused feeding deterrence and had a toxic effect on the aphids.

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Petersson, Maria, Ingrid Gustafson, and Mats Stading. "Comparison of microstructural and physical properties of two petroleum waxes." Journal of Materials Science 43, no. 6 (March 2008): 1869–79. http://dx.doi.org/10.1007/s10853-007-2417-9.

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Prüm, Bettina, Robin Seidel, Holger Florian Bohn, and Thomas Speck. "Plant surfaces with cuticular folds are slippery for beetles." Journal of The Royal Society Interface 9, no. 66 (June 8, 2011): 127–35. http://dx.doi.org/10.1098/rsif.2011.0202.

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Plant surfaces covered with three-dimensional (3D) waxes are known to strongly reduce insect adhesion, leading to slippery surfaces. Besides 3D epicuticular waxes, cuticular folds are a common microstructure found on plant surfaces, which have not been quantitatively investigated with regard to their influence on insect adhesion. We performed traction experiments with Colorado potato beetles on five plant surfaces with cuticular folds of different magnitude. For comparison, we also tested (i) smooth plant surfaces and (ii) plant surfaces possessing 3D epicuticular waxes. Traction forces on surfaces with medium cuticular folds, of about 0.5 µm in both height and thickness and a spacing of 0.5–1.5 µm, were reduced by an average of 88 per cent in comparison to smooth plant surfaces. Traction forces were reduced by the same order of magnitude as on plant surfaces covered with 3D epicuticular waxes. For surface characterization, we performed static contact angle measurements, which proved a strong effect of cuticular folds also on surface wettability. Surfaces possessing cuticular folds of greater magnitude showed higher contact angles up to superhydrophobicity. We hypothesize that cuticular folds reduce insect adhesion mainly due to a critical roughness, reducing the real contact area between the surface and the insect's adhesive devices.

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Mpanza, H. S., and A. S. Luyt. "Comparison of different waxes as processing agents for low-density polyethylene." Polymer Testing 25, no. 4 (June 2006): 436–42. http://dx.doi.org/10.1016/j.polymertesting.2006.01.008.

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Smith, Roger M., Jillian A. Marshall, Michael R. Davey, Kenneth C. Lowe, and J. Brian Power. "Comparison of volatiles and waxes in leaves of genetically engineered tomatoes." Phytochemistry 43, no. 4 (November 1996): 753–58. http://dx.doi.org/10.1016/0031-9422(96)00364-0.

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Oliveira, Antonio F. M., and Antonio Salatino. "Major Constituents of the Foliar Epicuticular Waxes of Species from the Caatinga and Cerrado." Zeitschrift für Naturforschung C 55, no. 9-10 (October 1, 2000): 688–92. http://dx.doi.org/10.1515/znc-2000-9-1003.

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Abstract The epicuticular waxes of leaves of four species (Aspidospermci pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) from the Caatinga, (a semi-arid ecosystem of Northeast Brazil) and four species (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) from the Cerrado, (a savanna ecosystem covering one third of the Brazilian territory), were analyzed. Six species contained a high content (above 60 μg.cm-2) of wax, four of them from the Caatinga. Triterpenoids and n-alkanes were the most frequent and abundant constituents found in the species from both habitats. The distribution of n-alkanes predominated by homologues with 27, 29, 31 and 33 carbon atoms, displayed no consistent differences between species from the two habitats. Lupeol, β-amyrin, epifriedelinol and ursolic acid were the triterpenoids found. Triterpenoids clearly predominate over alkanes in the waxes from the Cerrado species. The waxes of two evergreen species from the Caatinga yielded n-alkanes as predominant constituents. A comparison of foliar epicuticular waxes of native plants from ecosystems with different hydric constraints is discussed.

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Kerfourn, C., and J. P. Garrec. "Modifications in the alkane composition of cuticular waxes from spruce needles (Picea abies) and ivy leaves (Hedera helix) exposed to ozone fumigation and acid fog: comparison with needles from declining spruce trees." Canadian Journal of Botany 70, no. 4 (April 1, 1992): 861–69. http://dx.doi.org/10.1139/b92-110.

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Our study on the chemical composition of cuticular waxes showed that the configuration of alkane homologues, in needles from declining spruce trees as well as in artificially polluted ivy leaves and spruce needles, presented a significant shift towards lower molecular weight chains. On the contrary, in both materials ageing was characterized by increasing chain lengths. This work emphasizes the importance of the short and long carbon chains as representative parameters of chemical alteration of cuticular waxes. As far as alkanes are concerned, pollutants may change cuticular wax composition by acting on sites of their metabolic biosynthesis rather than through a direct passive chemical contact effect. Key words: Picea abies, Hedera helix, forest decline, ozone, acid fog, waxes, cuticles, alkanes.

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Yilmaz, Emin, Eda Keskin Uslu, and Ceren Öz. "Oleogels of Some Plant Waxes: Characterization and Comparison with Sunflower Wax Oleogel." Journal of the American Oil Chemists' Society 98, no. 6 (April 28, 2021): 643–55. http://dx.doi.org/10.1002/aocs.12490.

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Schulten, H. R., K. E. Murray, and N. Simmleit. "Natural Waxes Investigated by Soft Ionization Mass Spectrometry." Zeitschrift für Naturforschung C 42, no. 3 (March 1, 1987): 178–90. http://dx.doi.org/10.1515/znc-1987-0302.

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Field ionization (FI) and field desorption (FD) mass spectra of 35 aliphatic long-chain and branched long-chain compounds, representing the major six classes of constituents of natural waxes, are examined. In the FI mode the molecular ions are usually formed at comparatively low levels, while in FD such species are almost exclusively generated. In addition, some fast atom bombardment mass spectra, in the positive and negative ion mode, of selected lipids are recorded for comparison. In general, field ionization and field desorption techniques are found to be superior for mass spectrometric studies of low-polarity compounds. Examination of several natural waxes, such as Jojoba wax, preen gland wax of goose, beeswax and epicuticular wax of Norway spruce, shows that field desorption mass spectrometry has a most promising role in the characterization of wax components. The intense molecular ions allow the identification of the constituents of complex lipid mixtures without the need for derivatization. Thus, for the first time, the carbon number distribution, especially of the high-mass wax constituents can be established for the natural waxes investigated. For identification of high-mass wax constituents the present results suggest that field desorption mass spectra could be best employed in conjunction with class and individual separation of constituents by chromatographic procedures. The analysis of natural waxes is nowadays of major concern because of its importance in the problem of forest damage.

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Canizares, D., P. Angers, and C. Ratti. "A proposal standard methodology for the characterization of edible oil organogelation with waxes." Grasas y Aceites 71, no. 2 (May 19, 2020): 355. http://dx.doi.org/10.3989/gya.0106191.

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Saturated and trans fatty acids play a significant role in the plastic properties of food. However, health recommendations suggest limiting their intake. One approach which got the attention of researchers was to decrease the amount of saturated and trans fatty acids in food by the structuring of edible oils through the crystallization of waxes. The underlying mechanisms that lead to organogelation and the properties that characterize well-structured edible oil have been slow to fully understand due in part to a lack of standardization in their analysis which often makes the comparison between research results from different laboratories difficult. The aim of this work was to review previously reported methods for the characterization of organogelation using vegetable and animal waxes, and to propose a minimal standardization for an organogelation analysis.

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Hwang, Hong-Sik, Matthew Fhaner, Jill K. Winkler-Moser, and Sean X. Liu. "Oxidation of Fish Oil Oleogels Formed by Natural Waxes in Comparison With Bulk Oil." European Journal of Lipid Science and Technology 120, no. 5 (March 30, 2018): 1700378. http://dx.doi.org/10.1002/ejlt.201700378.

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Kühn, G., St Weidner, U. Just, and G. Hohner. "Characterization of technical waxes comparison of chromatographic techniques and matrix-assisted laser-desorption/ionization mass spectrometry." Journal of Chromatography A 732, no. 1 (April 1996): 111–17. http://dx.doi.org/10.1016/0021-9673(95)01255-9.

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Farid, Mohammed M., Yongsik Kim, and Atsushi Kansawa. "Thermal Performance of a Heat Storage Module Using PCM’s With Different Melting Temperature: Experimental." Journal of Solar Energy Engineering 112, no. 2 (May 1, 1990): 125–31. http://dx.doi.org/10.1115/1.2929644.

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A latent heat storage module was constructed, consisting of 45 cylindrical capsules fixed vertically in 15 rows. The capsules, made of 0.335-m long copper tubes having external diameters of 31.8 mm, were fixed in an insulated rectangular duct. Three commercial waxes having melting temperatures of 44°C, 53°C, and 64°C were selected. Each of the three sets of 15 tubes was filled with different wax. For comparison purposes, experiments were also done with a single commercial wax, having a melting temperature of 53°C, in all the tubes. During heat charge, hot air flowed across the capsules such that the melting temperature of the waxes decreased in the flow direction. Air flow direction was reversed during heat discharge. Experimental measurements showed some improvement in the heat transfer rates during both heat charge and discharge when three types of PCM’s were used. There was no improvement in the heat transfer rate during the sensible heat storage period, while a maximum increase of 15 percent was observed during the latent heat period. Theoretical predictions for the performance of the storage module were in reasonable agreement with the experimental measurements.

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IVANOVA, I. K., A. A. DIAKONOV, M. E. SEMENOV, and V. V. KORYAKINA. "MORPHOLOGY AND KINETICS OF PETROLEUM WAX DISSOLUTION IN HYDROCARBON SYSTEMS." Periódico Tchê Química 15, no. 30 (August 20, 2018): 570–77. http://dx.doi.org/10.52571/ptq.v15.n30.2018.574_periodico30_pgs_570_577.pdf.

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This paper studies the effect of solvent chemical nature on the kinetic parameters of dissolution and the morphology of the petroleum waxes. The kinetics of the petroleum wax dissolution in gas condensate and the hexane-cyclohexane-benzene mixture was examined on the torsion balance within the temperature range from 10 to 40°C. The process was described using the Erofeev-Kolmogorov equation. The following kinetic parameters were calculated: reaction rate, the order of reactions and effective energy for activation the wax dissolution in the studied solvents. It was found that the wax dissolution rate in the ternary composite is an order of magnitude greater and the activation energy is three times less in comparison with the process of wax dissolution in the gas condensate. The morphological features of the wax samples, treated by these solvents, were examined by means of scanning electron microscopy. It was found that in the ternary composite, wax has a porous structure and in the gas condensate, it is compressed. Thus, the identified kinetic and morphological behavior of petroleum waxes indicates the influence of the chemical nature of the solvent. The findings of this study can be useful when choosing a solvent for the paraffin deposits removal.

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Pokrovskiy, Oleg Igorevich, Denis Igorevich Prokopchuk, Saida Amiranovna Bagatelia, Sergei Alexandrovich Pokryshkin, Mikhail Olegovich Kostenko, Olga Olegovna Parenago, Anatolyevich Markolia, and Valery Vasilyevich Lunin. "COMPARISON OF LAURUS NOBILIS EXTRACTS COMPOSITION OBTAINED BY MICROWAVE EXTRACTION, SUPERCRITICAL FLUID EXTRACTION AND STEAM DISTILLATION." chemistry of plant raw material, no. 4 (December 27, 2019): 373–85. http://dx.doi.org/10.14258/jcprm.2019045431.

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A comparison of chemical composition of bay laurel extracts obtained by microwave extraction, supercritical fluid extraction and steam distillation was performed. Microwave extraction and steam distillation were shown to give similar essential oils. Microwave extract contains more monoterpenoid components, especially hydrocarbons. Steam distillation oil contains more sesquiterpenoid compounds, mostly oxygenated. SFE extract composition differs substantially from the ones obtained by two other methods. According to GC-MS data they contain much more sesquiterpenoid components, namely sesquiterpene lactones. This makes SFE a perspective candidate for isolation of biologically active compounds from laurel leaves. However, apart from valuable compound SFE extracts also contain substantial amounts of waxes as well as large quantities of some non-volatile component undetectable via GC-MS. In order to implement SFE into the practice of laurel processing one has to develop an approach for the fractionation of SFE extracts allowing isolating sesquiterpene lactone enriched fraction.

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Oros, Daniel R., Laurel J. Standley, Xiaojing Chen, and Bernd R. T. Simoneit. "Epicuticular Wax Compositions of Predominant Conifers of Western North America." Zeitschrift für Naturforschung C 54, no. 1-2 (February 1, 1999): 17–24. http://dx.doi.org/10.1515/znc-1999-1-205.

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The compositions of epicuticular waxes from conifers constituting the predom inant species of western North America were determined by GC and GC-MS. The primary components identified include alkanes, fatty acids, fatty alcohols, aldehydes, ketones, phytosterols, triterpenoids and wax esters. Average chain lengths (ACL) for alkanes in Oregon conifers decreased with increasing distance away from the Coastal range which suggests an adaptation by conifers to humid climate conditions. Differences in the chemical compositions make this information useful for chemotaxonomic purposes, for identifying natural organic aerosol input sources to the atmosphere, for comparison with the tracers in smoke emissions from burning of these biomass fuels, and for monitoring in assessment of global climate change

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Leide, Jana, Klaas G. J. Nierop, Ann-Christin Deininger, Simona Staiger, Markus Riederer, and Jan W. de Leeuw. "Leaf cuticle analyses: implications for the existence of cutan/non-ester cutin and its biosynthetic origin." Annals of Botany 126, no. 1 (March 28, 2020): 141–62. http://dx.doi.org/10.1093/aob/mcaa056.

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Abstract Background and Aims The cuticle of a limited number of plant species contains cutan, a chemically highly resistant biopolymer. As yet, the biosynthesis of cutan is not fully understood. Attempting to further unravel the origin of cutan, we analysed the chemical composition of enzymatically isolated cuticular membranes of Agave americana leaves. Methods Cuticular waxes were extracted with organic solvents. Subsequently, the dewaxed cuticular membrane was depolymerized by acid-catalysed transesterification yielding cutin monomers and cutan, a non-hydrolysable, cuticular membrane residue. The cutan matrix was analysed by thermal extraction, flash pyrolysis and thermally assisted hydrolysis and methylation to elucidate the monomeric composition and deduce a putative biosynthetic origin. Key Results According to gas chromatography–mass spectrometry analyses, the cuticular waxes of A. americana contained primarily very-long-chain alkanoic acids and primary alkanols dominated by C32, whereas the cutin biopolyester of A. americana mainly consisted of 9,10-epoxy ω-hydroxy and 9,10,ω-trihydroxy C18 alkanoic acids. The main aliphatic cutan monomers were alkanoic acids, primary alkanols, ω-hydroxy alkanoic acids and alkane-α,ω-diols ranging predominantly from C28 to C34 and maximizing at C32. Minor contributions of benzene-1,3,5-triol and derivatives suggested that these aromatic moieties form the polymeric core of cutan, to which the aliphatic moieties are linked via ester and possibly ether bonds. Conclusions High similarity of aliphatic moieties in the cutan and the cuticular wax component indicated a common biosynthetic origin. In order to exclude species-specific peculiarities of A. americana and to place our results in a broader context, cuticular waxes, cutin and cutan of Clivia miniata, Ficus elastica and Prunus laurocerasus leaves were also investigated. A detailed comparison showed compositional and structural differences, indicated that cutan was only found in leaves of perennial evergreen A. americana and C. miniata, and made clear that the phenomenon of cutan is possibly less present in plant species than suggested in the literature.

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Becker, Rafał, Soyol Dashbaldan, Cezary Pączkowski, Tomasz Golis, and Anna Szakiel. "Comparison of steroids and triterpenoids in leaf cuticular waxes of selected Polish and Russian cultivars and genotypes of edible honeysuckle." Phytochemistry Letters 30 (April 2019): 238–44. http://dx.doi.org/10.1016/j.phytol.2019.01.009.

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SYKORA, O., and E. J. SUTOW. "Comparison of the dimensional stability of two waxes and two acrylic resin processing techniques in the production of complete dentures." Journal of Oral Rehabilitation 17, no. 3 (May 1990): 219–27. http://dx.doi.org/10.1111/j.1365-2842.1990.tb00002.x.

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Rajchard, J. " Biologically active substances of bird skin: a review." Veterinární Medicína 55, No. 9 (October 7, 2010): 413–21. http://dx.doi.org/10.17221/2981-vetmed.

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Bird skin has a number of specific properties. The uropygial gland is a significant skin gland in many species. The secretion of this gland is particularly necessary for maintaining physical characteristics, including feather waterproofing. In some bird species this gland secretion has a repellent effect against potential mammalian predators; in other species it affects the final colour of feathers. In the investigated species of storks (genus Ciconia), secretions of the uropygial gland have been found to be mixtures of monoester waxes, diester waxes, triester waxes and triglycerides. Wax diesters were also found in the red knot Calidris canutus (order Charadriiformes). Lipid substances in the secretions of the rock dove (Columba livia) consist mainly of unsaturated fatty acids (59% secretion; mostly oleic acid – 37%, linoleic acid – 6% and arachidonic acid – 7%). Free fatty acids, which are decomposition products of epidermal lipids, can regulate microbial colonization of skin (e.g., by modification of pH); a shift of these values was detected in poultry in battery husbandry. Analysis of fatty acids from lipids shows the influence of age, diet, and also the relationship to feather pecking – the individual composition affects the smell and taste, and thus the attractiveness to other individuals. The antibacterial activity of skin secretions has been demonstrated. Secretions of the hoopoe (Upupa epops) have besides the function of maintenance of physical properties of feathers also a repellent effect on parasites and predators. Its active substance is a peptide bacteriocin, produced by strains of Enterococcus faecalis. This substance is active against a number of both G + and G-bacteria and helps to sustain the nest hygiene, it is also effective against Bacillus licheniformis that produces keratin-decompositing enzymes. A similar antimicrobial activity of uropygial secretion against bacteria which degrade feathers was demonstrated in the wild house finch Carpodacus mexicanus. Changes in skin microflora have been demonstrated in parrots kept for breeding in comparison with those living in the wild, which may have significance for husbandry practices and veterinary care. Passerines of the genus Pitohui and Ifrita living in New Guinea store in their skin and feather batrachotoxins, which they receive from food - beetles of the genus Choresine. These toxins are active against parasites (e.g. lice – Phthiraptera). In contrast, substances that act as potential attractants for hematophagous insects (e.g. mosquitoes of genus Culex) were found in the skin of chickens. Alcohols, ketones and diones were detected in these substances. The composition of uropygial gland secretions may be a guide in assessing the relatedness of bird species. Feather waxes can be analyzed also from old museum specimens. Lipid-enriched organelles, multigranular bodies in the epidermis mean that zebra finches (Taeniopygia castanotis) are facultatively waterproof, which appears to have a function in protecting the organism against dehydrating when water is unavailable.

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Hausnerova, Berenika, and Martin Novak. "Environmentally Efficient 316L Stainless Steel Feedstocks for Powder Injection Molding." Polymers 12, no. 6 (June 5, 2020): 1296. http://dx.doi.org/10.3390/polym12061296.

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In this study, environmentally convenient highly metal powder filled feedstocks intended for powder injection molding is presented. The composition of 60 vol % 316L stainless steel gas atomized powder feedstocks containing semicrystalline waxes: acrawax or carnauba wax and paraffin wax, combined with polyethylene glycol and modifier, was optimized to provide defect-free parts. Rheological as well as thermogravimetric analyses supported with scanning electron microscopy and metallography were employed to set up optimum conditions for molding, debinding and sintering. The performance of the novel feedstock was compared with currently available polyolefines-based materials, and results showed an efficiency enhancement due to the substantially lower (about 100 °C) mixing and molding temperatures as well as a reduction of debinding and sintering times at the simultaneous achievement of better mechanical properties in terms of elongation and tensile strength, in comparison to the mass production feedstock.

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Ly, Dang Thi Phuong, Nguyen Thi Nga, Dang Thi Minh Tuyet, Pham Minh Quan, and Andrey Imbs Borisovich. "Comparison of lipid compositions of soft coral Sinularia brassica collected in different coastal regions of Vietnam." Tạp chí Khoa học và Công nghệ biển 19, no. 2 (September 4, 2019): 285–91. http://dx.doi.org/10.15625/1859-3097/19/2/14046.

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Five soft coral samples belonging to the same specimen Sinularia brassica were collected in the coastal area of Ha Long Quang Ninh, Nhat Le beach, Quang Binh, Hon Vang - Thanh Hoa and Nha Trang areas (2014–2016), these samples were examined and analyzed by total lipid content, content and composition of lipid and fatty acids. Highest total lipid content was found in the sample SHM 09 collected in Nha Trang bay (1.11%), and the lowest total lipid content was in HL-SHM 07 collected in Ha Long, Quang Ninh (0.68%).The lipid composition of samples contained basic classes such as polar lipids, sterols, free fatty acids, triacylglycerols, monoankyldiacylglycerols, hydrocarbons and waxes. In studied soft corals, there are the appearance of all fatty acids from C12 to C24. There are differences in composition and content of lipids and fatty acids in samples collected in different locations: Samples collected at Nha Trang bay contain more polyunsaturated fatty acids than the other samples collected in Ha Long, Thanh Hoa, Quang Binh. Another two samples, collected in Hon Vang (Thanh Hoa) have similar composition and content of lipid classes, the composition and content of fatty acids in total lipids. The obtained results also show the significant impact of habitat and time of acquisition on the studied subject.

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Moreira, Celine, Richard Lloyd, Gavin Hill, Florence Huynh, Ana Trufasila, Faith Ly, Hasan Sawal, and Christopher Wallis. "Temperate UV-Accelerated Weathering Cycle Combined with HT-GPC Analysis and Drop Point Testing for Determining the Environmental Instability of Polyethylene Films." Polymers 13, no. 14 (July 20, 2021): 2373. http://dx.doi.org/10.3390/polym13142373.

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Polyethylene films are one of the most frequently used packaging materials in our society, due to their combination of strength and flexibility. An unintended consequence of this high use has been the ever-increasing accumulation of polyethylene films in the natural environment. Previous attempts to understand their deterioration have either focused on their durability using polymer analysis; or they have focused on changes occurring during outdoor exposure. Herein, this study combines those strategies into one, by studying the chemical and physical changes in the polyethylene structure in a laboratory using molecular weight and IR spectroscopic mapping analysis, combined with temperate UV-accelerated weathering cycles. This approach has been correlated to real-world outdoor exposure timeframes by parallel testing of the sample polyethylene films in Florida and France. The formation of polyethylene microparticles or polyethylene waxes is elucidated through comparison of drop point testing and molecular weight analysis.

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Holmes, M. G., and D. R. Keiller. "Effects of pubescence and waxes on the reflectance of leaves in the ultraviolet and photosynthetic wavebands: a comparison of a range of species." Plant, Cell & Environment 25, no. 1 (January 2002): 85–93. http://dx.doi.org/10.1046/j.1365-3040.2002.00779.x.

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Anderson, Scott C., Linh Chu, Chandra Bouma, Logan Beukelman, Rayna McLouth, Evan Larson, and Amanda M. Nienow. "Comparison of the Photodegradation of Imazethapyr in Aqueous Solution, on Epicuticular Waxes, and on Intact Corn (Zea Mays) and Soybean (Glycine Max) Leaves." Journal of Environmental Science and Health, Part B 54, no. 2 (October 4, 2018): 129–37. http://dx.doi.org/10.1080/03601234.2018.1511400.

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Galus, Sabina, Margaux Gaouditz, Hanna Kowalska, and Frédéric Debeaufort. "Effects of Candelilla and Carnauba Wax Incorporation on the Functional Properties of Edible Sodium Caseinate Films." International Journal of Molecular Sciences 21, no. 24 (December 8, 2020): 9349. http://dx.doi.org/10.3390/ijms21249349.

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The aim of this study was to evaluate the effects of candelilla (CAN) or carnauba wax (CAR) incorporation on functional properties of edible sodium caseinate (CAS) films. Glycerol and Tween-80 were used as the plasticizer and the emulsifier, respectively. The results showed that the incorporation of waxes increased film opacity, total color differences (∆E), and mechanical resistance and reduced film lightness, water vapor permeability (WVP), and elongation at break. Scanning electron microscopy showed heterogeneous structure of emulsion films with regular distribution of lipid particles. A different internal arrangement was observed as a function of the film composition with both layered and incorporated film structure. Films containing candelilla wax exhibited more regular lipid reorganization, which resulted in better water vapor barrier efficacy and mechanical resistance in comparison to control films. The presence of Tween-80 resulted in better dispersion of lipid particles in film-forming solutions and lower water solubility, lightness, film opacity, and water vapor permeability, whereas the total color differences (∆E) were significantly larger and the improvement in mechanical properties was also achieved.

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He, Ding, Bernd R. T. Simoneit, Blanca Jara, and Rudolf Jaffé. "Compositions and isotopic differences of iso- and anteiso-alkanes in black mangroves (Avicennia germinans) across a salinity gradient in a subtropical estuary." Environmental Chemistry 13, no. 4 (2016): 623. http://dx.doi.org/10.1071/en15128.

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Environmental contextMangroves dominate at the interface between land and sea, especially along tropical and subtropical coasts. To gain a better understanding of how mangroves respond to various environmental stress factors, we investigated the use of monomethylalkanes as potential chemical tracers for black mangroves. The application of these chemical tracers could elucidate how black mangroves respond to environmental stress such as sea level rise in mixed mangrove environments. AbstractA series of iso- and anteiso-monomethylalkanes (MMAs) with carbon numbers from C23 to C35 and C14 to C34 respectively were detected in Avicennia germinans. These compounds were present in varying amounts up to 54.1, 1.0 and 3.4µg g–1 dry weight in the leaves, bark and the crustose lichens attached to the bark of A. germinans respectively. These MMAs were not detected in the leaf waxes of Rhizophora mangle and Laguncularia racemosa, but were detected in significantly lower abundances (2–6% of that in A. germinans leaf wax) in the bark and lichen of R. mangle. Significant odd-carbon number distributions and even-carbon number distributions were observed for long chain (C ≥ 25) iso- (maximising at C31) and anteiso-MMAs (maximising at C32) respectively in A. germinans leaf wax. However, no obvious carbon number preferences were detected for bark and lichen. The long chain (LC) iso- and anteiso-MMAs in A. germinans leaf waxes were found to be enriched in 13C by 0.3–4.3 and 0.7–4.2 per mille (‰) compared to the n-alkanes with the same carbon numbers respectively across the salinity gradient of 19.7–32.0 practical salinity units (psu). In comparison, the LC iso- and anteiso-MMAs were found to be more depleted in D by 6.1–55.1 and 7.3–57.0 ‰ compared to the n-alkanes with same carbon numbers respectively. The results imply that A. germinans could be another important source of iso- and anteiso-alkanes in sediments and soils, and that these compounds could potentially be used as biomarkers for this species in mixed mangrove environments.

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Paroul, N., RL Cansian, M. Rossato, GF Pauletti, LA Serafini, L. Rota, P. Moyna, and H. Heinzen. "Use of palmae wax hydrocarbon fractions as chemotaxonomical markers in Butia and Syagrus." Brazilian Journal of Biology 69, no. 2 (May 2009): 353–61. http://dx.doi.org/10.1590/s1519-69842009000200017.

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The wax hydrocarbon fractions of native Butia and Syagrus species collected from Palms in different regions of the of Rio Grande do Sul state (Brazil) and in Rocha (Uruguay) were analyzed to evaluate their potential as chemotaxonomic markers. The wax was extracted with chloroform and the resulting wax was fractionated by preparative TLC. The hydrocarbon fractions were analyzed by GC-MS. Statistical analyses were completed with the Statistica 5.0 program. The total crude wax yields averaged 0.31% w.w-1 dried leaves for Butia samples and 0.28% for Syagrus samples. The linear hydrocarbons represented on average 15% of the total waxes in the case of Butia samples and 13.7% in Syagrus samples. Hentriacontane and triacontane were the main components of all samples. The comparison of the means showed significant differences among Butia and Syagrus samples, and amongst Butia samples collected in different localities. In the case of the Syagrus collections no consistent groupings could be made. In the case of Butia samples the formation of three groupings could be observed, which were consistent with the species described for their geographical distribution. These results are discussed in the paper.

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Soliman, Fathi S., Heba H. El-Maghrabi, Tamer Zaki, Amr A. Nada, and Fouad Zahran. "Enhancement of Separated Ultra Pure n-paraffin as Phase Change Materials (PCM) by W-Fe Bimetallic Oxides." Nanoscience & Nanotechnology-Asia 10, no. 6 (November 30, 2020): 817–26. http://dx.doi.org/10.2174/2210681209666190807153016.

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Objective:: Six ultra pure Paraffin Waxes (PW) were successfully fractionated at 35°, 30°, 25°, 20°, 15° and 10°C. The bimetallic oxide (Ferberite) was successfully synthesized by Microwave assisted method. Methods: Enhanced Phase Change Materials (PCMs) were designed by loading W/Fe bimetallic oxides in the ultra pure PW matrix at 1, 2, 3, 4 and 5 wt. %. paraffin wax, W/Fe bimetallic oxide and the resultant composite blends were characterized by X-ray Diffraction (XRD), Gas Chromatography (GC), Deferential Scanning Calorimetry (DSC), Polarized Optical Microscope (POM), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). In addition to testing the thermal conductivity of the designed blends. According to SEM, DSC and POM data, the prepared nanocomposite was homogeneously dispersed into the selected PW matrix. Results: Data revealed that thermal conductivity of the designed composite increases with increasing the loading ratio of W-Fe bimetallic oxides. The total latent heat storage ΔHT of the initial sample was improved from 295.91 J/g to 311.48 J/g at 5 wt. % loading percent. Conclusion:: Thermal conductivity was improved from 8.54 to 21.77 W/m2k with increasing up to 255% in comparison with pure paraffin wax.

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Rogowski, Isabelle, Jean-Yves Gauvrit, Didier Léonard, and Pierre Lanteri. "Typology of the gliding waxes in cross-country skiing: Comparison between classifications based on the chemical composition and those based on the physical and physicochemical properties." Cold Regions Science and Technology 43, no. 3 (December 2005): 140–49. http://dx.doi.org/10.1016/j.coldregions.2005.03.002.

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Sepúlveda, Francisco José, María Teresa Miranda, Irene Montero, José Ignacio Arranz, Francisco Javier Lozano, Manuel Matamoros, and Paloma Rodríguez. "Analysis of Potential Use of Linear Fresnel Collector for Direct Steam Generation in Industries of the Southwest of Europe." Energies 12, no. 21 (October 24, 2019): 4049. http://dx.doi.org/10.3390/en12214049.

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Industry sector has an important impact on primary energy consumption at the international level, and solar energy constitutes a real alternative to cover these energy needs partially. Among thermosolar concentration technologies, Linear Fresnel Collector (LFC) technology has some advantages that make it more accessible to industries. With the aim of providing new tools for easier decision-making processes, in the present work, several energy audits were carried out in industries (located in the south-west of Europe, with considerable steam consumptions), quantifying thermal and energy consumptions and defining both work schedules and seasonality. Afterwards, a comparison based on three factors was carried out: Thermal consumption regarding total industry consumption, the performance of the work during the solar schedule, and the quantification of the monthly average concentrated energy for a certain LFC facility. The analysis carried out according to these criteria showed different results for each case, making a global assessment necessary to suitably ponder each factor. This analysis ranked tomato industries as the most suitable for LFC technology, due to the fact that their main operating period was during the months with the highest solar isolation, and the solar schedule was completely integrated in a 24-h working day. Also, industrial waxes and laundries showed a good combination of both facts.

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Wongpreedee, Kageeporn, Adiruj Peerawat, Bongkot Phichaikamjornwut, and Duangkhae Bootkul. "Lost Wax Casting Conditions with Tourmaline In Situ." Key Engineering Materials 737 (June 2017): 595–98. http://dx.doi.org/10.4028/www.scientific.net/kem.737.595.

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The technique of stone-in-place casting has been established in jewelry production for three decades. However, the process is not widely used since it is limited to precious stones with high hardness and high stability at high temperature. This experiment tested tourmaline, which is a semi-precious gemstone having less hardness and less stability compared with precious stones. The objective was to achieve the conditions of a lost-wax casting process with tourmaline placed in waxes in the casting process. The experiment was divided into two parts. The first part was to understand the tolerance of tourmaline under the heating conditions. Natural tourmaline stones were investigated and compared inclusions tested at a temperature of 700°C. Tourmaline with ion-implantation was also heated to 700°C for comparison. The second part was to test tourmaline in-place casting with tree conditions of flask casting at 550°C, 625°C, and 700°C. The results showed that stones were able to tolerate as much as at 700°C. The inclusion growth of ion-implantation under heating to 700°C also observed the growth of inclusion in the same way as untreated tourmaline. The casting condition at 550°C showed better results. The highest probability of stones breaking after casting occurred in bezel settings.

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O'Reilly, Shane, Roger Summons, Gerald Mayr, and Jakob Vinther. "Preservation of uropygial gland lipids in a 48-million-year-old bird." Proceedings of the Royal Society B: Biological Sciences 284, no. 1865 (October 18, 2017): 20171050. http://dx.doi.org/10.1098/rspb.2017.1050.

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Although various kinds of organic molecules are known to occur in fossils and rocks, most soft tissue preservation in animals is attributed to melanin or porphyrins. Lipids are particularly stable over time—as diagenetically altered ‘geolipids’ or as major molecular constituents of kerogen or fossil ‘geopolymers’—and may be expected to be preserved in certain vertebrate tissues. Here we analysed lipid residues from the uropygial gland of an early Eocene bird using pyrolysis gas chromatography mass spectroscopy. We found a pattern of aliphatic molecules in the fossil gland that was distinct from the host oil shale sediment matrix and from feathers of the same fossil. The fossil gland contained abundant n -alkenes, n -alkanes and alkylbenzenes with chain lengths greater than 20, as well as functionalized long-chain aldehydes, ketones, alkylnitriles and alkylthiophenes that were not detected in host sediment or fossil feathers. By comparison with modern bird uropygial gland wax esters, we show that these molecular fossils are likely derived from endogenous wax ester fatty alcohols and fatty acids that survived initial decay and underwent early diagenetic geopolymerization. These data demonstrate the high fidelity preservation of the uropygial gland waxes and showcase the resilience of lipids over geologic time and their potential role in the exceptional preservation of lipid-rich tissues of macrofossils.

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He, Yue, Juzhi Hou, Erik T. Brown, Shuyun Xie, and Zhengyu Bao. "Timing of the Indian Summer Monsoon onset during the early Holocene: Evidence from a sediment core at Linggo Co, central Tibetan Plateau." Holocene 28, no. 5 (December 11, 2017): 755–66. http://dx.doi.org/10.1177/0959683617744267.

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The spatial and temporal variability, effects, and mechanisms of the Indian Summer Monsoon (ISM) have been investigated intensively during the past few decades. The pattern of a relatively strong ISM during the early to middle Holocene, and a relatively weak ISM in the late Holocene, has been widely demonstrated in both marine and continental records. However, the timing of the ISM onset during the early Holocene remains controversial. Here, we present oxygen isotope record from ostracods and hydrogen isotope record from sedimentary leaf waxes from a sediment core at Linggo Co, a glacier-fed lake on the central Tibetan Plateau, in order to investigate the onset of the ISM. The ostracod δ18O record indicates an early ISM onset at ~11.7 ka, whereas the leaf wax δD record indicates a later ISM onset at ~10 ka. This apparent two-step development of the ISM revealed by aquatic and terrestrial records is confirmed by principal component analysis of nine marine records from the ISM domain. The comparison between isotope records from Linggo Co and the marine records implies that the early ISM onset was likely linked to elevated temperatures in the Northern Hemisphere, while the later ISM onset may be related to intensified precipitation.

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Norsic, Sebastien, Cherif Larabi, Marco Delgado, Anthony Garron, Aimery de Mallmann, Catherine Santini, Kai C. Szeto, Jean-Marie Basset, and Mostafa Taoufik. "Low temperature hydrogenolysis of waxes to diesel range gasoline and light alkanes: Comparison of catalytic properties of group 4, 5 and 6 metal hydrides supported on silica–alumina." Catal. Sci. Technol. 2, no. 1 (2012): 215–19. http://dx.doi.org/10.1039/c1cy00256b.

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King, Matthew J. S., C. Paul Fairhurst, and Trevor J. Hill. "Solids Transport in Multiphase Flows—Application to High-Viscosity Systems." Journal of Energy Resources Technology 123, no. 3 (March 9, 2001): 200–204. http://dx.doi.org/10.1115/1.1385382.

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Solids transport in multiphase systems falls under the umbrella of “flow assurance.” Unlike issues such as waxes and hydrates, solids transport has received relatively little attention to date. This is especially true for solids transport in high-viscosity fluids such as Venezuelan crude, where viscosities around the 300–400-cP mark are commonly encountered. This paper describes some experiments performed on the BP Amoco 6-in. multiphase flow test facility located at Sunbury. These looked at the transport of field representative sand through a pipeline dip. Several fluids were selected for these experiments to examine the influence of liquid viscosity on the results. These were water, oil, and two different carboxymethylcellulose solutions (150 and 300 cP). These experiments showed that, in slug flow, water and low-viscosity oil were able to transport the sand uphill, whereas neither high-viscosity solution was able to transport the solids. This feature was examined in comparison to the model for solids transport in near-horizontal pipes discussed in this paper. Three-phase flow experiments (water-oil-air) were also performed to investigate the effect of oil or water prewetting of the solids on solids transport. If prewetted by water, the sand could not be moved by oil slugs. Once water was added to the system, the sand became increasingly mobile.

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SOTO-MUÑOZ, Lourdes, Victoria MARTÍNEZ-BLAY, María B. PÉREZ-GAGO, Asunción FERNÁNDEZ-CATALÁN, Maricruz ARGENTE-SANCHIS, and Lluís PALOU. "Starch-glyceryl monostearate edible coatings formulated with sodium benzoate control postharvest citrus diseases caused by Penicillium digitatum and Penicillium italicum." Phytopathologia Mediterranea 60, no. 2 (September 13, 2021): 265–79. http://dx.doi.org/10.36253/phyto-12528.

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The curative antifungal activity of edible composite coatings (ECs) based on pregelatinized potato starch-glyceryl monostearate (PPS-GMS) formulated with or without sodium benzoate (SB) to control green mould (caused by Penicillium digitatum) and blue mould (P. italicum) was assessed on ‘Orri’ mandarins, ‘Valencia’ oranges and ‘Fino’ lemons. These fruit were artificially inoculated with P. digitatum or P. italicum, treated by immersion in coating emulsions and compared to uncoated control fruit immersed in water and fruit immersed in 2% SB (w/v) aqueous solution. Treated fruit were then stored at either 20°C or commercial low temperature (5°C for mandarins and oranges, 12°C for lemons). Coatings without SB did not exhibit antifungal activity, whereas coatings containing 2% SB reduced incidence and severity of green and blue moulds, in comparison to the controls, on all citrus species and in all storage conditions, without differing from the aplication of 2% SB alone. For example, incidence reduction on ‘Fino’ lemons was from 99 to 0% after 7 d at 20°C, and from 99 to 30% after 2 weeks at 12°C. None of the treatments was phytotoxic. These results indicate that applications of SB as antifungal ingredient of PPS-GMS based ECs is a promising non-polluting alternative to control Penicillium postharvest decay of citrus, and these ECs are effective substitutes for conventional waxes amended with synthetic fungicides.

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Świercz, Anna. "Reaction of Coniferous Forest Vegetation to Particulate Deposition Under Alkaline Pressure." Folia Biologica et Oecologica 7 (December 12, 2011): 229–46. http://dx.doi.org/10.2478/v10107-009-0027-9.

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The aim of this study was to determine direction, rate and character of the changes in coniferous forest communities caused by anthropogenic stress factors (alkaline emission and imission) changing with time. To fulfil this goal, we have performed comprehensive studies of soils and plants at the study sites located in coniferous forest communities remaining under direct influence of cement and lime industry in the Świętokrzyskie Voivodeship. There were differences in the accumulation of elements in pine needles collected at alkalized sites in comparison with needles from the control site: Ca content was 2.5 times higher and Cu, Pb and Sr contents were 2–3 times higher, while Al and Fe, and Mn contents were twice and 10 times lower respectively. SEM analysis of morphological features of pine needle surface, in particular degree of preservation of epicuticular waxes can be as an indicator of assimilatory organ degeneration caused by dust deposition which induces wax layer erosion. Declining species number and biodiversity, particularly conspicuous at the Sitkówka site, was a general tendency observed over the study period (from 18 to 10 years). Other noticeable processes include slow regenerative changes of the community with a tendency towards higher contribution of acidophilic coniferous forest species with lower light and temperature requirements and suppression of meadow, ruderal and associated taxa. Further studies are required in order to define succession rate and direction of changes in species composition of these communities.

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Johnson, Chris E., Ronald J. Smernik, Thomas G. Siccama, David K. Kiemle, Zhihong Xu, and Daniel J. Vogt. "Using 13C nuclear magnetic resonance spectroscopy for the study of northern hardwood tissues." Canadian Journal of Forest Research 35, no. 8 (August 1, 2005): 1821–31. http://dx.doi.org/10.1139/x05-122.

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Nuclear magnetic resonance (NMR) spectroscopy is a useful tool for examining the structural chemistry of natural organic matter. The use of cross-polarization and magic-angle spinning to study 13C functionality (CPMAS 13C NMR) is convenient, but not always quantitative. We used various 13C NMR techniques to examine the structural chemistry of bark and wood of sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifolia Ehrh.), and yellow birch (Betula alleghaniensis Britt.). Spin counting experiments showed that 87%97% of the 13C in the samples was observable by CPMAS 13C NMR. A comparison of CPMAS and Bloch decay experiments revealed few differences in spectral properties. Together, these results suggest that CPMAS 13C NMR is quantitative for these tissues. We observed little variation in the structural chemistry of wood, either among samples of the same species or among species. Within-species variations in bark chemistry were greater than in wood, probably because of variations in environmental conditions. However, we observed no significant differences in bark chemistry among the species. Bark and wood chemistry differed significantly, with the bark spectra displaying greater contributions from lignin, suberin, waxes, and resins. Hardwood spectra differ from softwood spectra in the aromatic C regions because of the contribution of syringyl units to hardwood lignin. Hardwood bark appears to contain less tannins than softwood bark. Together, the quantitative and qualitative features of CPMAS 13C NMR spectra are useful for studying the ecology of living and detrital wood and bark.

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Jafari, Alireza, and Nick Cartwright. "EVALUATION OF A PARAMETRIC-TYPE WAVE TRANSFORMATION MODEL AGAINST FIELD AND LABORATORY DATA." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 51. http://dx.doi.org/10.9753/icce.v33.waves.51.

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Predicting wave properties via parametric wave propagation models are broadly used in many coastal engineering applications. Numerous researchers have refined these types of models to increase their accuracy including; Battjes and Janssen (1978), Thornton and Guza (1983), Baldock et al. (1998), and Alsina and Baldock (2007). Alsina and Baldock (2007), proposed an improved parametric wave propagation models for a non-saturated surfzone which returns relatively more accuracy in comparison to others. In this paper, the Alsina and Baldock (2007) model along with Baldock et al. (1998) and Thornton and Guza (1983), are applied to data collected in South-East Queensland under stormy and calm conditions as well as laboratory data. Some of the comparisons indicate the need to incorporate some additional energy loss at the break point to account for plunging type breakers where the existing bore dissipation model is insufficient.

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Chen, Qin Jim, Kelin Hu, and Andrew Kennedy. "NUMERICAL MODELING OF OBSERVED HURRICANE WAVES." Coastal Engineering Proceedings 1, no. 32 (February 2, 2011): 30. http://dx.doi.org/10.9753/icce.v32.waves.30.

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Extensive field measurements of wind waves in deep and shallow waters during Hurricane Gustav (2008) in the Gulf of Mexico have been simulated by the spectral wave prediction model, SWAN. First, a parametric asymmetric hurricane wind model with three major improvements is used to generate hurricane wind fields for the wave model. The changes of water level near the coast are taken into account by using a storm surge model. Forced by the verified hurricane winds and hindcasted water levels, the wave model performs fairly well in comparison to the observed wave heights and periods in both deep and shallow waters except a few locations with complex bathymetry and landscape. In addition to the hurricane wind field that controls the accuracy of wave modeling in deep water, wave-surge interaction plays an important role in the wave growth and transformation in shallow water. Wave spectral comparisons show that the white-capping formulation of Westhuysen et al. (2007) generally outperforms the default formulation of Komen et al. (1984) in SWAN under hurricane conditions. The model result indicates that the asymmetry of hurricane winds and the hurricane translation result in the maximum wind waves occurring on the right side of the hurricane track and propagating in the direction parallel to the hurricane translation direction, consistent with field observations.

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Jackson, D. R., A. Gadian, N. P. Hindley, L. Hoffmann, J. Hughes, J. King, T. Moffat-Griffin, et al. "The South Georgia Wave Experiment: A Means for Improved Analysis of Gravity Waves and Low-Level Wind Impacts Generated from Mountainous Islands." Bulletin of the American Meteorological Society 99, no. 5 (May 2018): 1027–40. http://dx.doi.org/10.1175/bams-d-16-0151.1.

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AbstractGravity waves (GWs) play an important role in many atmospheric processes. However, the observation-based understanding of GWs is limited, and representing them in numerical models is difficult. Recent studies show that small islands can be intense sources of GWs, with climatologically significant effects on the atmospheric circulation. South Georgia, in the South Atlantic, is a notable source of such “small island” waves. GWs are usually too small scale to be resolved by current models, so their effects are represented approximately using resolved model fields (parameterization). However, the small-island waves are not well represented by such parameterizations, and the explicit representation of GWs in very-high-resolution models is still in its infancy. Steep islands such as South Georgia are also known to generate low-level wakes, affecting the flow hundreds of kilometers downwind. These wakes are also poorly represented in models.We present results from the South Georgia Wave Experiment (SG-WEX) for 5 July 2015. Analysis of GWs from satellite observations is augmented by radiosonde observations made from South Georgia. Simulations were also made using high-resolution configurations of the Met Office Unified Model (UM). Comparison with observations indicates that the UM performs well for this case, with realistic representation of GW patterns and low-level wakes. Examination of a longer simulation period suggests that the wakes generally are well represented by the model. The realism of these simulations suggests they can be used to develop parameterizations for use at coarser model resolutions.

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Ozalp, Mustafa Kemal, and Serdar Beji. "TIME DOMAIN COMPARISONS OF MEASURED AND SPECTRALLY SIMULATED BREAKING WAVES." Coastal Engineering Proceedings, no. 35 (June 23, 2017): 12. http://dx.doi.org/10.9753/icce.v35.waves.12.

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For realistic wave simulations in the nearshore zone besides nonlinear interactions, the dissipative effects of wave breaking must also be taken into account. This paper presents the applications of a spectral nonlinear wave model with a dissipative breaking mechanism introduced by Beji and Nadaoka (1997). Results obtained for spectral components are converted to the time series and compared with Beji and Battjes' (1993) laboratory measurements and the field measurements of Nakamura and Katoh (1992) in the surf zone. While the model predicts the spilling-type breaking of irregular waves in acceptable agreement with the measurements in time domain, the agreement is unsatisfactory for plunging-type breakers.

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Bender, Christopher, Ashley Kauppila, and Hunter Bredesen. "SIMULATIONS OF HURRICANE MATTHEW SURGE AND WAVES; COMPARISONS TO MEASUREMENTS." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 72. http://dx.doi.org/10.9753/icce.v36.waves.72.

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Hurricane Matthew formed into a hurricane in the eastern Caribbean and rapidly intensified with peak intensity occurring in late September 2016 when the storm reached Saffir-Simpson Category 5 strength with 160 mph winds (Stewart, 2017). After leaving the Caribbean, Hurricane Matthew moved northward and remained close to the coasts of Florida, Georgia, South Carolina, and North Carolina and caused elevated water levels, large waves, and extensive coastal erosion.

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JIANG, QINGFANG, and RONALD B. SMITH. "V-waves, bow shocks, and wakes in supercritical hydrostatic flow." Journal of Fluid Mechanics 406 (March 10, 2000): 27–53. http://dx.doi.org/10.1017/s0022112099007636.

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The structure of the bow shock, V-wave, and the related wave drag and wake in supercritical ambient flow are investigated for homogeneous hydrostatic single-layer flow with a free surface over an isolated two-dimensional (i.e. h(x, y)) obstacle. The two control parameters for this physical system are the ratio of obstacle height to fluid depth and the Froude number F = U/√gH. Based on theoretical analysis and numerical modelling, a steady-state regime diagram is constructed for supercritical flow. This study suggests that supercritical flow may have an upstream bow shock with a transition from the supercritical state to the subcritical state near the centreline, and a V-shock in the lee without a state transition. Unlike subcritical flow, neither a flank shock nor a normal lee shock is observed, due to the local supercritical environment. Both the bow shock and V-shock are dissipative and reduce the Bernoulli constant, but the vorticity generation is very weak in comparison with subcritical ambient flow. Thus, in supercritical flow, wakes are weak and eddy shedding is absent.Formulae for V-wave shape and V-wave drag are given using linear theory. Both formulae compare well with numerical model runs for small obstacles.These results can be applied to air flow over mountains, river hydraulics and coastal ocean currents with bottom topographies.

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Bender, Christopher, William Miller, Ashley Naimaster, and Tucker Mahoney. "WAVE MODELING WITH SWAN+ADCIRC FOR THE SOUTH CAROLINA COASTAL STORM SURGE STUDY." Coastal Engineering Proceedings 1, no. 33 (October 25, 2012): 48. http://dx.doi.org/10.9753/icce.v33.waves.48.

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The South Carolina Surge Study (SCSS) used the tightly coupled SWAN+ADCIRC model to simulate tropical storm surge events. The tightly coupled model allowed calculation of wave-induced water level changes within the storm surge simulations. Inclusion of the wave-induced water level changes represents a more physics-based approach than previous methods that added wave setup after model simulations ended. Development of the SWAN+ADCIRC model included validation of water levels to local tidal forcing and for three historical hurricanes — Hazel (1954), Hugo (1989), and Ophelia (2005). The validation for waves did not include Hurricane Hazel because measured data was unavailable. Additional comparisons with WAM model results provided supplemental support to the SWAN model results. Model output applied in comparisons included contour plots of maximum wave parameters, time series of wave parameters at selected locations, and wave spectra.

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Irschik, Kai, Stefan Schimmels, and Hocine Oumeraci. "BREAKING CRITERIA FOR LABORATORY EXPERIMENTS BASED ON THE PHASE-TIME-METHOD (PTM)." Coastal Engineering Proceedings 1, no. 32 (January 27, 2011): 6. http://dx.doi.org/10.9753/icce.v32.waves.6.

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Breaking waves generated by focusing of transient wave packets have been analyzed. By a comparison of video data and gauge measurements the threshold frequency for the use of the PTM as a breaking criterion is derived. The present result is slightly higher than the original value of Zimmermann & Seymour (2002) for spilling breakers, but confirms the results of Irschik & Oumeraci (2006). Additionally the use of the zero down-cross period Tz instead of the peak period TP is investigated. Both definitions lead for the present conditions with plunging breakers to almost identical results.

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Moura, Theo Garcia Rolim de, Claudio Freitas Neves, and José Claudio De Faria Telles. "APPLYING BIVARIATE HHT TO HORIZONTAL VELOCITIES." Coastal Engineering Proceedings 1, no. 32 (February 2, 2011): 66. http://dx.doi.org/10.9753/icce.v32.waves.66.

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The Hilbert-Huang Transform (HHT) is extended to the time series analysis of wave orbital velocities resulting from the superposition of waves propagating in different directions. On a theoretical basis, it is shown that an apparently chaotic velocity signal may result from the interaction of three or more waves, each one with its own period and direction of propagation. Such result is compatible with records of PUV instruments. The comparison between bivariate HHT with Fourier directional analysis shows several advantages of the former, such as identification of wave groups and non-linear interaction components.

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Edge, Billy L., Margery F. Overton, Robert A. Dalrymple, Alexis Hérault, Giuseppe Bilotta, M. Onur Kurum, and Kevin Gamiel. "APPLICATION OF GPU SMOOTH PARTICLE HYDRODYNAMICS: WAVE RUNUP AND OVERTOPPING ON COMPOSITE SLOPES." Coastal Engineering Proceedings 1, no. 33 (December 31, 2012): 74. http://dx.doi.org/10.9753/icce.v33.waves.74.

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Smooth Particle Hydrodynamics is a Lagrangian meshless numerical method with substantially improved capabilities in simulation of both fluid dynamics and solid mechanics due to its meshless nature. GPUSPH is an implementation of Smoothed Particle Hydrodynamics (SPH) on Nvidia CUDA-enabled (graphics) cards. In this paper the GPUSPH is applied to runup and overtopping applications and compared with experimental results from Roos and Battjes for a plane slope and Oaks, Edge and Lynett for complex bathymetry representing a complex levee transition. Results for both models show good comparison with experimental data and suggest GPUSPH as a reasonable tool for complex runup and overtopping problems.

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Norkus, Zenonas, Aelita Ambrulevičiūtė, and Jurgita Markevičiūtė. "Real Wages of Lithuanian Construction Workers from 1913 to 1939 (Measured in Subsistence and Welfare Ratios) in a Cross-National Comparison." Lithuanian Historical Studies 23, no. 1 (December 28, 2019): 25–57. http://dx.doi.org/10.30965/25386565-02301002.

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This article provides two comparisons: (1) a cross-time comparison of real wages of skilled and unskilled workers in Kaunas before the First World War and during the interwar period; and (2) a cross-national quantitative comparison of the wages of unskilled workers in Kaunas and the capital cities of most European countries during the same period. For the second comparison, we use the findings of researchers who applied Robert C. Allen’s methodology of real wage estimation. In this methodology, the wages of unskilled construction workers (known in interwar Lithuania as zimagoras) are used as proxies for the wages of unskilled urban workers, and those of construction site carpenters provide a sample for skilled workers’ wages. Real wages are measured in subsistence and welfare ratios, indicating the distances separating the purchasing power of wages from the subsistence level of a single worker (subsistence ratio = 1 meaning absolute poverty) or his family (welfare ratio = 1 meaning absolute poverty). Subsistence or absolute poverty levels are defined by regionally adjusted (to variations in survival needs) minimum consumption baskets. The main findings are: (1) although during the first decade of independence (in the 1920s) the real wages of unskilled construction workers in Kaunas were lower than in 1913, by 1938 they had markedly surpassed the pre-First World War level; (2) in no year with available data did the real wages of unskilled construction workers in Kaunas fall below the absolute poverty level; (3) the real wages of skilled construction workers in Kaunas had markedly surpassed the pre-First World War level even before the Great Depression in the early 1930s, and remained above this level even in the worst years of the depression; (4) the real wages of skilled and unskilled construction workers in Kaunas in 1913 were no lower than in metropolitan centres of the Russian Empire; (5) in the period 1927 to 1929, the wages of unskilled construction workers in Kaunas were lower than in Moscow, but largely surpassed Russian wages in the 1930s, when Stalin’s policy of industrialisation forced them below the subsistence level; (6) the real wages of unskilled construction workers in Kaunas in the 1930s surpassed those in Riga and Tallinn. While this finding is surprising, it concurs with earlier (2007) findings by Gediminas Vaskela, who compared the mean wages of workers and employees in the Baltic countries in the period 1938 to 1940.

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Journal articles on the topic 'Comparison of waxes'

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