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Journal articles on the topic 'Differential weathering'

Author: Grafiati
Published: 4 June 2021
Last updated: 16 February 2022

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1

White, Art F., Thomas D. Bullen, Marjorie S. Schulz, Alex E. Blum, Thomas G. Huntington, and Norman E. Peters. "Differential rates of feldspar weathering in granitic regoliths." Geochimica et Cosmochimica Acta 65, no. 6 (March 2001): 847–69. http://dx.doi.org/10.1016/s0016-7037(00)00577-9.

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2

Deng, Zhiyong, Fengchong Lan, and Jiqing Chen. "Differential Distribution Analysis and Region and Grade Regulation on Auto-Parts Weathering External Factors with Non-Uniform Thermal Environment." Applied Sciences 10, no. 15 (July 25, 2020): 5116. http://dx.doi.org/10.3390/app10155116.

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It is difficult to comprehensively master and precisely regulate the external factors distribution of automobile weathering in non-uniform thermal environment as well as the consequent disequilibrium weathering problem, while exploring weather-resistant materials in uniform thermal environment. Thus, a numerical calculation method for the weathering external factors is proposed, on the basis of annual experimental study on the outdoor weathering inconsistencies of auto-parts. The time–space distribution characteristics and day–night variation rules of the external factors are studied, and the disequilibrium weathering mechanism among parts is revealed from the perspective of non-uniform distribution of external factors. The laws of automotive physical parameters, orientations and locations, as well as their influences on external factors distribution are analyzed in detail, and hereby the targeted schemes to effectively reduce the local external factor intensity and the thermal gradient between parts are investigated. The method can be used to rapidly predict weathering external factors distribution of vehicle exposed to outdoor in any direction during day and night, so as to provide auto-parts with differentiated test schemes in accelerated tests and IP/DP box tests, and it also contributes to present some pertinence guidance for the accurate regulation of automobile disequilibrium weathering on regions at different levels.
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3

Guo, Yan Fen, You Ji Tao, Gan Xin Jie, Jun Wang, Xiao Dong Zhang, Li Fen Hu, and Xin Liu. "Degradation Behavior of Pure Polystyrene Subjected to Two Natural Climate Types and the Simulated Effect of Artificial Accelerated Weathering." Applied Mechanics and Materials 713-715 (January 2015): 2632–39. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.2632.

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Pure polystyrene (PS) was subjected to natural weathering in Qionghai (QH) and Ruoqiang (RQ) of China, representing hot and humid climate and xerothermic climate respectively. The degradation profile of pure PS was studied by Fourier Transform Infrared (FTIR) Spectroscopy, Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS) and Spectrophotometer. Artificial accelerated weathering tests protocol A and B were carried out to simulate hot and humid climate and xerothermic climate respectively. Results show that pure PS degrade slowly at the initial stage and then become faster. Color shift could be an appropriate indicator for evaluating simulated effect of artificial accelerated weathering and protocol A simulate hot and humid climate perfectly while protocol B turns out weak for xerothermic climate.
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4

McCarroll, Danny. "Differential weathering of feldspar and pyroxene in an arctic-alpine environment." Earth Surface Processes and Landforms 15, no. 7 (November 1990): 641–51. http://dx.doi.org/10.1002/esp.3290150706.

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5

Ibarra, Daniel E., Jeremy K. Caves, Seulgi Moon, Dana L. Thomas, Jens Hartmann, C. Page Chamberlain, and Kate Maher. "Differential weathering of basaltic and granitic catchments from concentration–discharge relationships." Geochimica et Cosmochimica Acta 190 (October 2016): 265–93. http://dx.doi.org/10.1016/j.gca.2016.07.006.

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6

Andersson, P. O. D., and R. H. Worden. "Stratigraphic variations in mudstone mineral assemblages from a submarine fan-complex: Karoo Basin, South Africa." Clay Minerals 41, no. 4 (December 2006): 839–52. http://dx.doi.org/10.1180/0009855064140223.

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AbstractDespite the high-grade diagenesis experienced by the Skoorsteenberg Formation mudstones, Tanqua Karoo basin, South Africa, geochemical data have been interpreted to reveal primary mineralogy and so help understand provenance evolution. The geochemical signatures show systematic variations related to stratigraphy. The main changes in mudstones from the lower to the upper part of the section include: (1) an increase in the feldspar content of the primary sediment and a decrease in the content of Al-rich clay (probably dioctahedral smectite); (2) a decrease in the degree of chemical weathering of the sediment, representing a change to a dryer and/or cooler climate; (3) an increase in TiO2/Al2O3 representing increasing mafic sources; (4) an increase in CaO/(K2O+CaO) also possibly representing increasing mafic sources. Mass flux and differential diagenesis are unlikely to be responsible for the depth-related changes since the rocks have undergone the same degree of high-grade diagenesis and the mudstones are interrupted by other lithologies, so disturbing any sort of diffusion gradient. These variations could plausibly be the result of one or more of differential weathering, evolving provenance characteristics or variable hydrodynamic fractionation of the sediment. The ratio of Zr/Y, a possible indicator of hydrodynamic fractionation, increases only slightly and irregularly up-section. There is no relationship between the silica content, representative of the quartz-silt content of the sediment, and TiO2/Al2O3 showing that the amount of quartz, and so the degree of hydrodynamic fractionation, has not controlled mudstone geochemistry. The stratigraphic increase in feldspar content, the decrease in Al-rich clay content and increase of both TiO2/Al2O3 and CaO/(K2O+CaO) must be due to a combination of marginally evolving provenance characteristics (more mafic and felsic rocks exposed to weathering with time) and changes in the degree of rock weathering (less chemical weathering with time).
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7

Zhu, Tengwei, Feng Huang, Jing Liu, Qian Hu, and Wei Li. "Effects of inclusion on corrosion resistance of weathering steel in simulated industrial atmosphere." Anti-Corrosion Methods and Materials 63, no. 6 (November 7, 2016): 490–98. http://dx.doi.org/10.1108/acmm-05-2015-1538.

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Purpose This paper aims to investigate the atmospheric corrosion mechanism of structural materials to develop more advanced corrosion-control technologies and cost-reduction strategies. As a second phase in steels, the non-metallic oxide inclusions are considered to not only affect the mechanical properties of steel but also the corrosion resistance of steel. So, an important research goal in this paper is to investigate the indoor accelerated corrosion kinetics of Q450NQR1 weathering steel, analyzing the galvanic polarity of different inclusions in electrochemical corrosion microcell between the inclusion and steel matrix and then elucidating the influence mechanism of inclusions on corrosion resistance of weathering steel. Design/methodology/approach Two methods of inclusion modification are usually used to improve the properties of weathering steel: one is calcium treatment on aluminum killed steel and the other one is rare earth (RE) modification. Wet/dry cyclic immersion corrosion test field emission scanning electron microscopy (FE-SEM) metallographic optical microscope. Findings The indoor accelerated corrosion kinetics of Q450NQR1 weathering steel could be divided into two stages with different log (thickness loss, D)-log (time, t) fitting functions, and the effect of inclusions on the corrosion resistance of Q450NQR1 weathering steel was only reflected in the initial stages of corrosion. The inclusions of CaS in Ca-modified test steel and RE oxides and sulfides in RE-modified test steel were preferentially dissolved in acid media, slowing down the corrosion rate of steel matrix, but the non-metallic inclusion Al2O3 may accelerate the corrosion rate of the steel matrix as a form of differential aeration corrosion. Originality/value The effects of inclusions on corrosion resistance of Q450NQR1 weathering steel was investigated by dry–wet cycle immersion test and FE-SEM. The effect of inclusions on the corrosion resistance of Q450NQR1weathering steel was only reflected in the initial stages of corrosion. The inclusions of CaS in Ca-modified test steel and rare earth (RE) oxides and sulfides in RE-modified test steel were preferentially dissolved in acid media, slowing down the corrosion rate of steel matrix, but the non-metallic inclusion Al2O3 may accelerate corrosion rate of the steel matrix as a form of differential aeration corrosion.
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8

Darmody, Robert G., Colin E. Thorn, and John C. Dixon. "Differential rock weathering in the ‘valley of the boulders', kärkevagge, swedish lapland." Geografiska Annaler: Series A, Physical Geography 90, no. 3 (September 2008): 201–9. http://dx.doi.org/10.1111/j.1468-0459.2008.339.x.

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9

Todisco, Dominique, and Hervé Monchot. "Bone Weathering in a Periglacial Environment: The Tayara Site (KbFk-7), Qikirtaq Island, Nunavik (Canada)." ARCTIC 61, no. 1 (March 1, 2009): 87. http://dx.doi.org/10.14430/arctic9.

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Bone weathering analysis of the Palaeoeskimo Tayara site (Qikirtaq Island, Nunavik, Canada) documents site taphonomy in the Arctic periglacial environment. Like a majority of sites in the eastern Canadian Arctic, Tayara has a faunal assemblage dominated by marine mammals (seal, walrus, and beluga whale) and some terrestrial mammals (caribou, fox, and bear). Statistical and spatial analyses of five weathering stages reveal that large mammal bone preservation is generally good and does not seem to be influenced by taxonomic and skeletal differences. The good preservation of the faunal assemblage seems to have been favored by the burial of bones and their incorporation into the active layer, which suggests only limited mechanical deterioration (i.e., freeze-thaw or wet-dry cycles, or both) before or at the time of burial. Burial depth partly explains the degree of bone weathering. Indeed, the well-preserved bones are found mainly where burial is associated with thicker overlying sediments. This implies rapid bone burial with a low degree of exposure to temperature changes and atmospheric processes. However, analysis also shows the presence of highly weathered bones where burial is associated with thicker overlying sediments. Consequently, differential bone depth probably does not explain all bone-weathering variability within the site. These results show the importance of examining bone weathering before any archaeozoological and paleoethnographic interpretations.
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10

Butylina, Svetlana, Marko Hyvärinen, and Timo Kärki. "Weathering of wood-polypropylene and wood-wollastonite-polypropylene composites containing pigments in Finnish climatic conditions." Pigment & Resin Technology 44, no. 5 (September 7, 2015): 313–21. http://dx.doi.org/10.1108/prt-08-2014-0066.

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Purpose – The purpose of this paper is to study the resistance of wood-polypropylene and wood-wollastonite-polypropylene composites containing pigments to natural weathering. Design/methodology/approach – Natural weathering of composites was conducted in Finnish climatic conditions for one year. The colour of the composites was determined with a spectrophotometer, the morphology of the composite surface was analysed by scanning electron microscopy (SEM), and the changes in the polymer structure in surface layer of the composites were analysed with differential scanning calorimetry (DSC). Charpy impact strength was determined with an impact tester. Findings – The pigments used in this study reduced the colour change of the composites exposed to outdoor weathering as compared with the un-coloured composite. The carbon black pigment was more effective than the iron oxide pigment. Moreover, only the carbon black pigment was found to reduce the degradation of the surface layer of the composites. The addition of the carbon black pigment had a positive effect on the dimensional stability of the composites in a water absorption test. Only the combination of the carbon black pigment and wollastonite resulted in a composite which was capable to retain its Charpy impact strength both after one year of outdoor weathering and cyclic treatment. Research limitations/implications – This study is a part of continuous research on the development of wood-polymer composites (WPUs) suitable for outdoor applications in Finnish climatic conditions. The first part of the study, which has been published earlier, showed the results of weathering of composites in accelerated tests in comparison with 1,000 hours outdoor exposure during summer time (June and July). Outdoor weathering limited to 1,000 hours cannot give an objective view on the weathering behaviour of composites in Finnish climatic conditions. The results of the current study were obtained from one-year outdoor exposure of composites. Originality/value – The wood-polypropylene composite made with the combination of the carbon black pigment and wollastonite can be recommended for outdoor applications. The study provides useful information on the resistance of wood-polypropylene composites to weathering in Finnish climatic conditions.
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11

Place, Joachim, Deyan Draganov, Alireza Malehmir, Christopher Juhlin, and Chris Wijns. "Crosscoherence-based interferometry for the retrieval of first arrivals and subsequent tomographic imaging of differential weathering." GEOPHYSICS 84, no. 4 (July 1, 2019): Q37—Q48. http://dx.doi.org/10.1190/geo2018-0405.1.

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Exhumation of crust exposes rocks to weathering agents that weaken the rocks’ mechanical strength. Weakened rocks will have lower seismic velocity than intact rocks and can therefore be mapped using seismic methods. However, if the rocks are heavily weathered, they will attenuate controlled-source seismic waves to such a degree that the recorded wavefield would become dominated by ambient noise and/or surface waves. Therefore, we have examined the structure of differential weathering by first-break traveltime tomography over a seismic profile extending approximately 3.5 km and acquired at a mining site in Zambia using explosive sources and a source based on the swept-impact seismic technique (SIST). Seismic interferometry has been tested for the retrieval of supervirtual first arrivals masked by uncorrelated noise. However, use of crosscorrelation in the retrieval process makes the method vulnerable to changes in the source signal (explosives and SIST). Thus, we have developed a crosscoherence-based seismic-interferometry method to tackle this shortcoming. We investigate the method’s efficiency in retrieving first arrivals and, simultaneously, correctly handling variations in the source signal. Our results illustrate the superiority of the crosscoherence- over crosscorrelation-based method for retrieval of the first arrivals, especially in alleviating spurious ringyness and in terms of the signal-to-noise ratio. These benefits are observable in the greater penetration depth and the improved resolution of the tomography sections. The tomographic images indicate isolated bodies of higher velocities, which may be interpreted as fresh rocks embedded into a heavily weathered regolith, providing a conspicuous example of differential weathering. Our study advances the potential of seismic methods for providing better images of the near surface (the critical zone).
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12

Kajaks, Janis, Karlis Kalnins, and Juris Matvejs. "Accelerated Aging of WPCs Based on Polypropylene and Plywood Production Residues." Open Engineering 9, no. 1 (June 19, 2019): 115–28. http://dx.doi.org/10.1515/eng-2019-0014.

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AbstractA lot of researchers are closely connected with natural, lignocellulose fibre containing bio-composites producing and studies. Various of polymer matrices, mainly polyolefins, combinations with natural fibres as a reinforcement are used. Our studies are focused on polypropylene based bio-composites containing birch plywood production by-product sanding dust (PSD) accelerated weathering processes. The nine groups of the samples with different composition were exposed in an accelerated weathering chamber for a total duration of the 1032 h. The surface colour, gloss, whiteness degree, micro-hardness and the tensile properties of the samples during the weathering were tested. In addition, the weathered surfaces were characterized by scanning electron microscopy (SEM) studies and by differential scanning calorimetry (DSC) investigations. The obtained results showed the following sight: after the weathering the surface of all samples is faded, also the changes of the gloss and of the whiteness degree occurs, but microhardness of the surface of specimens has decreased. The tensile strength of the samples changes a little, in the same time the tensile modulus increases significantly due to the decrease of the deformation ability of the polypropylene matrix and recrystallization processes in PP. The SEM images taken at the 100 and 500 times of the magnification revealed a lot of the different shape and sizes cracks on the surface of the weathered samples. DSC measurements showed the increase of the degree of crystallinity of the polypropylene after the weathering due to the recrystallization process in the polypropylene matrix.
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13

Mysiukiewicz, Olga, Mateusz Barczewski, Katarzyna Skórczewska, Joanna Szulc, and Arkadiusz Kloziński. "Accelerated Weathering of Polylactide-Based Composites Filled with Linseed Cake: The Influence of Time and Oil Content within the Filler." Polymers 11, no. 9 (September 12, 2019): 1495. http://dx.doi.org/10.3390/polym11091495.

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This paper presents the effects of accelerated weathering on the properties of polylactide (PLA) composites filled with linseed cake. The particle-shaped waste filler with different linseed oil content (0.9–39.8 wt %) was incorporated with constant amount of 10 wt % to a polymeric matrix and subjected to accelerated weathering tests with different exposition times. The structure of the composites, their mechanical, thermal, and thermo-mechanical properties were evaluated by means of scanning electron microscopy, tensile test, dynamic mechanical thermal analysis, and differential scanning calorimetry prior to and after weathering. The results of the measurements were analyzed in reference to the amount of crude oil contained in the filler. The behavior of the multiphase composite during weathering was described. It was found that the oil-rich samples during the first stage of the process showed increased resistance to hydrolytic degradation due to their relatively high crystallinity. The presence of water and elevated temperatures caused swelling of the filler and cracking of the polymeric matrix. Those discontinuities enabled the plasticizing oil to be rinsed out of the composite and thus water penetrated into the samples. As a result, the PLA-based composites containing oil-rich linseed cake were found to be more vulnerable to hydrolytic degradation in a longer time.
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14

Genthon, Pierre, Jean-Lambert Join, and Julie Jeanpert. "Differential weathering in ultramafic rocks of New Caledonia: The role of infiltration instability." Journal of Hydrology 550 (July 2017): 268–78. http://dx.doi.org/10.1016/j.jhydrol.2017.04.059.

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15

Seo. "Effect of geological characteristics on differential weathering of low-graded metasedimentary rock slopes." Journal of Korean Tunnelling and Underground Space Association 15, no. 4 (2013): 375. http://dx.doi.org/10.9711/ktaj.2013.15.4.375.

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16

SCHWID, MAXWEL F., SHUHAI XIAO, MORRISON R. NOLAN, and ZHIHUI AN. "DIFFERENTIAL WEATHERING OF DIAGENETIC CONCRETIONS AND THE FORMATION OF NEOPROTEROZOIC ANNULATED DISCOIDAL STRUCTURES." PALAIOS 36, no. 1 (January 29, 2021): 15–27. http://dx.doi.org/10.2110/palo.2020.018.

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ABSTRACT Annulated discoidal structures are common in many Neoproterozoic and particularly Ediacaran successions. Their interpretations, especially their biogenicity, are often contentious. Some of them (e.g., Aspidella and related forms) are demonstrably biological structures and may represent holdfasts of frondose Ediacara-type organisms. Others may represent fluid escape structures or tool marks produced by the rotation of tethered organisms. Here we show that differential chemical weathering of diagenetic dolomite concretions can also produce annulated discoidal structures that could be mistaken as Ediacara-type discoidal fossils. Using transmitted-light and cathodoluminescence microscopy in conjunction with Raman and energy dispersive spectroscopy, we analyzed dolomitized discoidal concretions embedded in a phosphorite matrix from the Ediacaran Miaohe Member of South China. Our observations reveal that pervasive and displacive syn-compactional dolomitization of the concretions and differential compaction of surrounding sediment led to the formation of biconvex or upward-convex primary laminae within the concretions. When exposed along parting surfaces and/or bedding planes, disparities in the weatherability of the warped primary laminae within the concretions resulted in the formation of circular annuli that mimic Neoproterozoic discoidal structures, some of which have been contentiously interpreted as discoidal fossils. These findings emphasize the importance of thin-section petrographic observations in the study of discoidal dubiofossils in order to assess their origin as diagenetic concretions or as discoidal macrofossils.
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17

Mansur, Lamya, Alan Williams, Keith D. Bartle, and Mark W. Raynor. "CHARACTERIZATION OF THE INITIAL WEATHERING OF PETROLEUM HYDROCARBONS BY FTIR SPECTROSCOPY AND SUPERCRITICAL FLUID CHROMATOGRAPHY." International Oil Spill Conference Proceedings 1989, no. 1 (February 1, 1989): 427–31. http://dx.doi.org/10.7901/2169-3358-1989-1-427.

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ABSTRACT Chemical changes resulting from the weathering processes of oils have been investigated on a bench scale weathering apparatus. A multicomponent oil simulating crude oil was developed for this purpose. Hydrocarbon concentrations resulting from evaporation and dissolution were measured using Fourier transform infrared (FTIR) spectroscopy and interpreted by a computer program (CIRCOM), which uses the method of principal components regression for multicomponent quantitative analysis. This method could be fast and accurate for quantitative assessments of changes in chemical and physical properties of an oil. However, this study outlines only the chemical measurements of saturated and aromatic hydrocarbon composition. Experiments were also undertaken to study weathering processes on oil droplets. In this technique single droplets of crude oil were suspended in water, the trends of dissolution were studied, and the behavior of the remaining heavy fraction assessed by FTIR spectroscopy and capillary column supercritical fluid chromatography (SFC). SFC was used to identify compounds, especially high molecular weight alkanes, and their changes in concentration with time in suspension in water. The results show that the main changes in the composition of oil droplets in stagnant waters are loss of low molecular weight material and differential loss of high boiling n-alkanes compared to their isoprenoid counterparts. FTIR spectroscopy and SFC proved powerful techniques for detecting minimal weathering processes, including oxidation, dissolution, and microbial degradation.
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18

Awad, Sameer A., and Eman M. Khalaf. "Evaluation of the photostabilizing efficiency of polyvinyl alcohol–zinc chloride composites." Journal of Thermoplastic Composite Materials 33, no. 1 (October 11, 2018): 69–84. http://dx.doi.org/10.1177/0892705718804585.

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Accelerated weathering of polyvinyl alcohol (PVA) and PVA reinforced with 20 wt% of zinc chloride (ZnCl2) was investigated. The developed PVA composites were subjected to 100, 200, and 300 h of accelerated weathering exposure times. The effects of exposure on the PVA composites were characterized by Fourier transform infrared (FTIR), thermal properties as thermogravimetric analysis and differential scanning calorimetry, the mechanical and morphology properties, and X-ray diffraction analysis. The results of FTIR displayed that lower carbonyl and hydroxyl indexes are due to PVA composite. The results of mechanical tests showed that the accelerated weathering reduced the tensile strength of PVA. However, PVA composites exhibited fewer reduction of the tensile strength values. PVA composites exhibited better thermal stability after extent to ultraviolet irradiation. The storage modulus from dynamic mechanical analysis results that displayed a higher value for the storage modulus is related to PVA composites, compared to PVA. Before exposure, PVA composite showed a high intensity, compared to PVA. After exposure to accelerated weathering, the intensity of all samples shifted and decreased. Scanning electron microscopic micrographs showed that the surface of the PVA composites had fewer defects compared to the PVA after exposure. The results of characterization revealed that 20% of ZnCl2 into the PVA made less vulnerable to environmental degradation, and these PVA composites are suitable as packaging films for use in outdoor applications.
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19

Awad, Sameer A., Christopher M. Fellows, and Seyed S. Mahini. "Evaluation of bisphenol A-based epoxy resin containing multiwalled carbon nanotubes to improve resistance to degradation." Journal of Composite Materials 53, no. 21 (December 3, 2018): 2981–91. http://dx.doi.org/10.1177/0021998318816784.

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The influence of exposure to UV light and moisture on the durability of a multiwalled carbon nanotube(MWCNT)/epoxy nanocomposite was investigated. Samples of epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) cured with 2,2,4-trimethylene-1,6-hexadiamine (TMDA), and epoxy nanocomposite containing 0.5% MWCNT were exposed to different accelerated weathering times between one and six months. Changes in surface chemistry, mechanical properties (tensile tests), thermal properties (thermogravimetric analysis and differential scanning calorimetry), and morphology were evaluated before and after exposure to accelerated weathering for a period of up to six months. Epoxy nanocomposite (DGEBA–TMDA/0.5%MWCNT) samples had improved thermal stability and resistance to degradation, compared to epoxy resin (DGEBA–TMDA). The effect of MWCNT at reducing degradation was more pronounced than previously found for resins prepared with hydrogenated DGEBA.
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Admassu, Yonathan, Abdul Shakoor, and Neil A. Wells. "Evaluating selected factors affecting the depth of undercutting in rocks subject to differential weathering." Engineering Geology 124 (January 2012): 1–11. http://dx.doi.org/10.1016/j.enggeo.2011.09.007.

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21

Martínez-Martínez, Javier, Anna Arizzi, and David Benavente. "The Role of Calcite Dissolution and Halite Thermal Expansion as Secondary Salt Weathering Mechanisms of Calcite-Bearing Rocks in Marine Environments." Minerals 11, no. 8 (August 23, 2021): 911. http://dx.doi.org/10.3390/min11080911.

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This research focuses on the analysis of the influence of two secondary salt weathering processes on the durability of rocks exposed to marine environments: chemical dissolution of rock forming minerals and differential thermal expansion between halite and the hosting rock. These processes are scarcely treated in research compared to salt crystallisation. The methodology followed in this paper includes both in situ rock weathering monitoring and laboratory simulations. Four different calcite-bearing rocks (a marble, a microcrystalline limestone and two different calcarenites) were exposed during a year to a marine semiarid environment. Exposed samples show grain detachment, crystal edge corrosion, halite efflorescences and microfissuring. Crystal edge corrosion was also observed after the laboratory simulation during a brine immersion test. Calcite chemical dissolution causes a negligible porosity increase in all the studied rocks, but a significant modification of their pore size distribution. Laboratory simulations also demonstrate the deterioration of salt-saturated rocks during thermal cycles in climatic cabinet. Sharp differences between the linear thermal expansion of both a pure halite crystal and the different studied rocks justify the registered weight loss during the thermal cycles. The feedback between the chemical dissolution and differential thermal expansion, and the salt crystallisation of halite, contribute actively to the rock decay in marine environments.
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22

Nguyen, Khoi Van, Tung Thanh Nguyen, Duc Trung Nguyen, and Ha Thi Thu Pham. "EFFECT OF CaCO3 FILLER ON THE DEGRADATION OF HIGH DENSITY POLYETHYLENE (HDPE) FILM CONTAINING PROOXIDANTS." Vietnam Journal of Science and Technology 56, no. 3B (September 13, 2018): 79. http://dx.doi.org/10.15625/2525-2518/56/3b/12770.

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The aim of this work is investigation of effect of CaCO3 filler on the degradation of high density polyethylene (HDPE) films containing stearate salts as prooxidant additves. The films with thickness of 30 µm were prepared by adding 0.3 % (w/w) prooxidant additives mixture (manganese (II) stearate/feric stearate/cobalt (II) stearate ratio of 18:4:1) and CaCO3 filler from 5 to 20 % (w/w) in HDPE resins using twin screw extruder. The films were carried out accelerated weathering treatment according to ASTM G154 standard (340 nm UV lamp, 8 hours UV, 4 hours condensation at 50 0C) for maximum duration of 96 hours. The mechanical properties, FTIR analysis, Differential Scanning Calorimetry (DSC), Thermo gravimetric analysis (TGA) and Scanning Electron Microscope (SEM) were used to assess the changes in the structure and surface morphology of films during accelerated weathering. The results showed that the degradation rate of HDPE films decreased by adding CaCO3 filler and versused with CaCO3 filler content. FTIR traces revealed that CaCO3 filler didn’t affect to the mechanism of polyethylene degradation. After 96 hours of aceelerated weathering treatment, the elongation at break of the HDPE film with 5 % CaCO3 almost unchanged while this value of the HDPE films with 10 and 20 % CaCO3 decreased significantly (96 % and 100 %, respectively).
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ADMASSU, YONATHAN, and ABDUL SHAKOOR. "Cut Slope Design for Stratigraphic Sequences Subject to Differential Weathering: A Case Study from Ohio." Environmental & Engineering Geoscience 21, no. 4 (November 2015): 311–24. http://dx.doi.org/10.2113/gseegeosci.21.4.311.

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24

Pye, K., A. S. Goudie, and A. Watson. "Petrological influence on differential weathering and inselberg development in the Kora area of central Kenya." Earth Surface Processes and Landforms 11, no. 1 (January 1986): 41–52. http://dx.doi.org/10.1002/esp.3290110106.

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25

Putra, Andius D., Masaya Takahashi, and Mamoru Kikumoto. "Weathering-induced deformation of crushed weak rocks and its countermeasure." E3S Web of Conferences 92 (2019): 09003. http://dx.doi.org/10.1051/e3sconf/20199209003.

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Geotechnical issues such as differential settlements have been reported usually in embankments made of materials derived from weak rocks such as mudstones, siltstones, and shales. The primary cause of the issue is a gradual weakening due to weathering. Crushed weak rocks tend to turn into smaller particles under repeated wetting and drying processes. This phenomenon is a mechanical-hydraulic process known as “slaking”. The present paper discusses the deformation of crushed weak rocks due to slaking and its countermeasure. We performed a series of one-dimensional slaking tests on several weak rocks. We first performed one-dimensional compression tests on dried samples, and applied wetting and drying cycles to the samples while keeping the compression stress constant. The test results revealed that particle size distribution of the samples was broadened due to cyclic wetting and drying processes and that significant compression was exhibited. Moreover, we explored possible countermeasures for reducing the slaking-induced deformation and revealed that compacting the soil to a denser state is the most effective way in reducing the slaking-induced deformation of the crushed mudstone.
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Slack, Richard D., Daniel A. Ebrom, John A. McDonald, and Robert H. Tatham. "Thin layers and shear‐wave splitting." GEOPHYSICS 58, no. 10 (October 1993): 1468–80. http://dx.doi.org/10.1190/1.1443361.

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The near‐surface weathering layer is considered by many to be strongly anisotropic. Any shear‐wave signal passing through this low‐velocity layer will inherit, to some degree, the anisotropic response of this layer. For thin weathering layers, information about previous anisotropic events may be distorted; when the thickness of this layer approaches some physically defined limit, however, a previous layer’s anisotropic signature is completely overwritten. Hodograms and Alford rotations are typically used to analyze shear‐wave splitting in the presence of azimuthal anisotropy. When the time‐delay generated by an azimuthally anisotropic layer is ⩾τ/8, where τ = one period of the wavelet’s dominant frequency, distortion of a shear‐wave signal is great enough to degrade the accuracy of the interpretation in hodogram analysis. We found that Alford rotations are superior to visual hodogram analysis when the time delay between the fast and slow shear‐waves is less than τ/8. When two azimuthally anisotropic layers with different symmetry axes exist, however, interpretations generated through both hodogram analysis and Alford rotations begin to deteriorate when the time‐delay generated by the second layer is ⩾τ/8. Recent field work has shown that the weathering layer may possess differential shear‐wave birefringence in excess of 25 percent. If we assume a dominant frequency of 40 Hz and shear‐wave velocities of [Formula: see text] and [Formula: see text], then an azimuthally anisotropic weathering layer may be as little as 5.8 m (19 ft) thick when it begins to overwrite a previous layer’s anisotropic response. When the time delay generated by a second anisotropic layer is ⩾τ (46.4 m, 152 ft thick), information about earlier anisotropic events are completely overwritten.
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27

Löhr, S. C., M. Grigorescu, and M. E. Cox. "Iron nodules in ferric soils of the Fraser Coast, Australia: relicts of laterisation or features of contemporary weathering and pedogenesis?" Soil Research 51, no. 2 (2013): 77. http://dx.doi.org/10.1071/sr12372.

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The genesis of ferruginous nodules and pisoliths in soils and weathering profiles of coastal southern and eastern Australia has long been debated. It is not clear whether iron (Fe) nodules are redox accumulations, residues of Miocene laterite duricrust, or the products of contemporary weathering of Fe-rich sedimentary rocks. This study combines a catchment-wide survey of Fe nodule distribution in Poona Creek catchment (Fraser Coast, Queensland) with detailed investigations of a representative ferric soil profile to show that Fe nodules are derived from Fe-rich sandstones. Where these crop out, they are broken down, transported downslope by colluvial processes, and redeposited. Chemical and physical weathering transforms these eroded rock fragments into non-magnetic Fe nodules. Major features of this transformation include lower hematite/goethite and kaolinite/gibbsite ratios, increased porosity, etching of quartz grains, and development of rounded morphology and a smooth outer cortex. Iron nodules are commonly concentrated in ferric horizons. We show that these horizons form as the result of differential biological mixing of the soil. Bioturbation gradually buries nodules and rock fragments deposited at the surface of the soil, resulting in a largely nodule-free ‘biomantle’ over a ferric ‘stone line’. Maghemite-rich magnetic nodules are a prominent feature of the upper half of the profile. These are most likely formed by the thermal alteration of non-magnetic nodules located at the top of the profile during severe bushfires. They are subsequently redistributed through the soil profile by bioturbation. Iron nodules occurring in the study area are products of contemporary weathering of Fe-rich rock units. They are not laterite duricrust residues nor are they redox accumulations, although redox-controlled dissolution/re-precipitation is an important component of post-depositional modification of these Fe nodules.
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Dubey, P. N., B. P. Bhaskar, P. Chandran, B. Singh, and B. K. Mishra. "Geochemistry of some ferruginous soils of Kerala, India." Journal of Applied and Natural Science 8, no. 1 (March 1, 2016): 196–207. http://dx.doi.org/10.31018/jans.v8i1.773.

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The four representative ferruginous soils on lateritic cover developed over Precambrian rocks in parts of Kottayam of Kerala were studied to understand the weathering pattern and genesis through geochemistry. These soils are strongly to moderately acidic, reddish brown with low Cation exchange capacity CEC and base saturation having SiO2 - 33 to 57%, Al2O3 - 16-31%, Fe2O3 - 8 to 15% and TiO2 -0.7 to 1.4%. Kanjirapalli (P3) and Athirampuzha (P4) soil series were more intensely weathered as compared to the Kinalur (P1) and Chingavanam series (P2) with silica to alumina -iron ratio less than 2 and had a significant negative relationship with Chemical index of alteration CIA ( -0.75**), Harnois index ( -0.678**), Richie index (-0.953**) and Plagioclase Index of Weathering (-0.705**). The trace elemental concentration ranges were above the values of world soils having an enrichment index more than 1 in Kanjirapalli series (P3) and Ni contamination in genetic horizons (Ni > 200µgg-1 ). The cluster analysis showed similar major oxide concentration pattern in Group -1 and Group - 2 but varied in trace elemental pattern with Cr > Ba > Cu in Group - 1 and Cu > Cr > Ba in Group- 2 soils whereas Zr > Ni > Mn in Group - 3 to Ni > Mn > Zr in Group - 4 soils. The study further showed that differential rate of weathering in soils under tropical climate was further accelerated due to anthropogenic activities such as improper land use practices and deforestation on sleep slopes.
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Das, Biswa Ranjan, Dasaradhan Bharathi, Deepak Kumar Yadav, Manoj Kumar Singh, Thako Hari Goswami, and Namburi Eswara Prasad. "DEVELOPMENT OF SPECIALTY COATED FABRICS FOR CANOPY OF INFLATABLE MILITARY TENT (IMT) FOR FOREST AREA." International Journal of Research -GRANTHAALAYAH 9, no. 2 (February 24, 2021): 81–92. http://dx.doi.org/10.29121/granthaalayah.v9.i2.2021.3387.

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The principal objectives of this present work were to develop novel coated fabrics in olive green (OG) colour to serve as canopy for inflatable military tent (IMT) for forest area. Two varieties of coated fabrics were developed by coating of specific grade aliphatic thermoplastic polyurethane (TPU) on Nylon fabrics and one more with coating of plasticized polyvinyl chloride (PVC) on Polyester fabric. The construction parameters and properties of the substrate basic fabrics used for coating were evaluated and reported. The various functional parameters such as breaking strength and elongation%, tear strength, bursting strength, waterproofness, flame retardancy, flexing, accelerated ageing (-400C and 700C), blocking, ultraviolet (UV) radiation protection and colour fastness to washing and light of the coated fabrics were measured and reported with details, along with an elaborate note on the preparatory process pursued for the development of these coated fabrics. The most suitable coated fabric for canopy of IMT was selected based on the evaluated functional features. Further, the thermal analysis was carried out for the selected coated fabric using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) for assessing its heat resistance. The shelf-life of the selected coated fabric was assessed by evaluating the residual strength (tensile and bursting), measured by subjecting it to accelerated and natural weathering tests. A special device was fabricated to carry out natural weathering test. Statistical analysis was performed at 95% significance level to estimate the actual strength (tensile and bursting) loss upon weathering.
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30

Jiménez-Espinosa, Rosario, Mercedes Vázquez, and Juan Jiménez-Millán. "Differential weathering of granitic stocks and landscape effects in a Mediterranean climate, Southern Iberian Massif (Spain)." CATENA 70, no. 2 (July 2007): 243–52. http://dx.doi.org/10.1016/j.catena.2006.09.001.

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31

Nagel, Norbert, Hans Bock, and Peter Eller. "Dimorphism and inclusion compounds of N,N′-di(benzenesulfonyl)-p-phenylenediamine." Acta Crystallographica Section B Structural Science 56, no. 2 (April 1, 2000): 234–44. http://dx.doi.org/10.1107/s0108768199005790.

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Crystal structures of a new polymorph of N,N′-(p-phenylene)bis(benzenesulfonamide) (C18H16N2O4S2) and of two inclusion compounds with acetone [(CH3)2CO] and dimethylsulfoxide [2(CH3)2SO], respectively, have been determined at 150 K. For a more reliable comparison, the structure of the already known polymorph of N,N′-di(benzenesulfonyl)-p-phenylenediamine has been redetermined under identical conditions. In addition, the phase transformation behavior has been examined by differential scanning calorimetry and the crystallization conditions of both polymorphs including their formation by weathering of the inclusion compounds were investigated.
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32

Sam, S. T., H. Ismail, and H. P. S. Abdul Khalil. "Degradation of epoxidized natural rubber compatibilized linear low density polyethylene/ soya powder blends: the effect of natural weathering." Journal of Polymer Engineering 33, no. 7 (October 1, 2013): 579–88. http://dx.doi.org/10.1515/polyeng-2013-0002.

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Abstract In the present study, linear low density polyethylene (LLDPE)/soya powder blends were compatibilized with epoxidized natural rubber (ENR 50) and exposed to natural weathering. The exposure period for the blends was 1 year. It was found that the degradability of the compatibilized blends was higher than that of uncompatibilized blends. Fourier transform infrared (FTIR) spectra, the tensile test, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) were applied to analyze the degradability of the blends. IR spectra showed that the carbonyl index (CI) of the blends increased as a function of exposure period and soya powder content. The compatibilized blends gave higher carbonyl indices. The retention tensile strength and elongation at break (Eb) of the compatibilized blends after weathering was generally lower than for the uncompatibilized blends. The increase of crystallinity also indicated a reduction of the amorphous portion after degradation. The higher crystallinity in compatibilized blends further confirms the higher degradability of ENR 50 compatibilized blends. The weight loss and molecular weight change indicated that the incorporation of ENR 50 into LLDPE/soya powder blends can enhance the degradability of the blends upon outdoor exposure.
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33

Gao, Shan, Wen-Bin Zhang, Xia-Fang Sheng, Lin-Yan He, and Zhi Huang. "Chitinophaga longshanensis sp. nov., a mineral-weathering bacterium isolated from weathered rock." International Journal of Systematic and Evolutionary Microbiology 65, Pt_2 (February 1, 2015): 418–23. http://dx.doi.org/10.1099/ijs.0.067249-0.

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A Gram-stain-negative, aerobic, yellow-pigmented, non-motile, non-spore-forming, rod-shaped bacterial strain, Z29T, was isolated from the surface of weathered rock (potassic trachyte) from Nanjing, Jiangsu Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain Z29T belongs to the genus Chitinophaga in the family Chitinophagaceae . Levels of 16S rRNA gene sequence similarity between strain Z29T and the type strains of recognized species of the genus Chitinophaga ranged from 92.7 to 98.2 %. The main fatty acids of strain Z29T were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. It also contained menaquinone 7 (MK-7) as the respiratory quinone and homospermidine as the main polyamine. The polar lipid profile contained phosphatidylethanolamine, unknown aminolipids, unknown phospholipids and unknown lipids. The total DNA G+C content of strain Z29T was 51.3 mol%. Phenotypic properties and chemotaxonomic data supported the affiliation of strain Z29T with the genus Chitinophaga . The low level of DNA–DNA relatedness (ranging from 14.6 to 29.8 %) to the type strains of other species of the genus Chitinophaga and differential phenotypic properties demonstrated that strain Z29T represents a novel species of the genus Chitinophaga , for which the name Chitinophaga longshanensis sp. nov. is proposed. The type strain is Z29T ( = CCTCC AB 2014066T = LMG 28237T).
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34

Zhang, Ke, Peng Tan, Guowei Ma, and Ping Cao. "Modeling of the progressive failure of an overhang slope subject to differential weathering in Three Gorges Reservoir, China." Landslides 13, no. 5 (December 30, 2015): 1303–13. http://dx.doi.org/10.1007/s10346-015-0672-4.

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35

Fisk, Shera, Francesco Berna, Deborah C. Merrett, and Hugo F. V. Cardoso. "Post-mortem gross composition changes and differential weathering of immature and mature bone in an experimental burial environment." Journal of Archaeological Science: Reports 26 (August 2019): 101904. http://dx.doi.org/10.1016/j.jasrep.2019.101904.

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36

Dahanayake, K., and S. M. N. D. Subasinghe. "Variable mineralogy and solubility of a terrestrial phosphorite resulting from differential weathering phenomena — an example from Sri Lanka." Chemical Geology 84, no. 1-4 (July 1990): 42–44. http://dx.doi.org/10.1016/0009-2541(90)90159-5.

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37

Zdraveva, Emilija, Budimir Mijovic, Emi Govorcin Bajsic, and Vedrana Grozdanic. "The efficacy of electrospun polyurethane fibers with TiO2 in a real time weathering condition." Textile Research Journal 88, no. 21 (July 26, 2017): 2445–53. http://dx.doi.org/10.1177/0040517517723025.

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This study focuses on the behavior of electrospun polyurethane fibers filled with nano, micro spheres and nanotube TiO2, thus nTiO2, mTiO2 or TiNT, under real time ultraviolet (UV) radiation. Analyses were conducted using scanning electron microscopy (SEM), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis and differential scanning calorimetry (DSC) techniques. Significant changes of thermoplastic polyurethane (TPU) + 0.5% nTiO2 and TPU + 0.5% mTiO2 fibers morphology, that is, agglomerated TiO2 particles, were observed on material surfaces due to TPU fiber degradation, also supported by FTIR spectra given as reduction in the peaks intensities after UV radiation, especially in the case of TPU + 0.5% nTiO2. Further, after UV radiation, the initial degradation temperature reduction of the hard segment for all materials was up to 40℃. A significant reduction in the final degradation temperature (from 397.8℃ to 274.1℃) was noticed for the mTiO2 filled fibers, suggesting their photocatalytic activity, while Tg was increased up to 20℃ for almost all fillers added to TPU, thus indicating lower molecular chain mobility upon UV radiation.
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38

Tasaki, Ryo, and Akihiro Ogawa. "Two-Component Model for Crude Oil Evaporation and its Application to Weathering Prediction." International Oil Spill Conference Proceedings 1999, no. 1 (March 1, 1999): 271–80. http://dx.doi.org/10.7901/2169-3358-1999-1-271.

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ABSTRACT The model approximates a crude oil as a mixture of an evaporating and non-evaporating component of which the physico-chemical properties are calculated by their composing fractions. The ordinary differential equation with separated variables derived from the model yields a concept of the evaporation time constant TQ that is defined by the initial oil properties and thickness, and the ambient temperature and wind speed. The evaporation ratios Q measured in flume tests on six types of Middle East crude oils are analyzed for the elapsed time non-dimensionalized by TQ. The measured values collapse well to a single straight line Q-log(t/TQ) for each type of oil, independently of emulsification and wave disturbance. A single line common to all the six types of oils is enough for rough estimation. A method using the common line or, more accurately, a line derived from the distillation test of each type of oil is proposed for evaporation prediction. Further analyses of the test results reveal the one-to-one correspondence between evaporation and properties (viscosity and density) of evaporated residual water-free oil. Formulae using the correspondence are suggested for estimating the properties of residual oil. The influences of substrates and thickness of an oil slick on evaporation and oil properties were examined in a small-scale laboratory. The laboratory tests are discussed as a useful procedure for obtaining basic prediction data.
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39

Vu, Thevu, Peyman Nikaeen, William Chirdon, Ahmed Khattab, and Dilip Depan. "Improved Weathering Performance of Poly(Lactic Acid) through Carbon Nanotubes Addition: Thermal, Microstructural, and Nanomechanical Analyses." Biomimetics 5, no. 4 (November 17, 2020): 61. http://dx.doi.org/10.3390/biomimetics5040061.

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To understand the interrelationship between the microstructure and degradation behavior of poly(lactic acid) (PLA), single-walled carbon nanotubes (CNTs) were introduced into PLA as nucleating agents. The degradation behavior of PLA-CNT nanocomposites was examined under accelerated weathering conditions with exposure to UV light, heat, and moisture. The degradation mechanism proceeded via the Norrish type II mechanism of carbonyl polyester. Differential scanning calorimetry (DSC) studies showed an increase in glass transition temperature, melting temperature, and crystallinity as a result of the degradation. However, pure PLA showed higher degradation as evidenced by increased crystallinity, lower onset decomposition temperature, embrittlement, and a higher number of micro-voids which became broader and deeper during degradation. In the PLA-CNT nanocomposites, CNTs created a tortuous pathway which inhibits the penetration of water molecules deeper into the polymer matrix, making PLA thermally stable by increasing the initial temperature of mass loss. CNTs appear to retard PLA degradation by impeding mass transfer. Our study will facilitate designing environmentally friendly packaging materials that display greater resistance to degradation in the presence of moisture and UV light.
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40

Ponti, S., M. Pezza, and M. Guglielmin. "The development of Antarctic tafoni: Relations between differential weathering rates and spatial distribution of thermal events, salts concentration and mineralogy." Geomorphology 373 (January 2021): 107475. http://dx.doi.org/10.1016/j.geomorph.2020.107475.

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41

Maher, Kate, and Friedhelm von Blanckenburg. "Surface ages and weathering rates from 10Be (meteoric) and 10Be/9Be: Insights from differential mass balance and reactive transport modeling." Chemical Geology 446 (December 2016): 70–86. http://dx.doi.org/10.1016/j.chemgeo.2016.07.016.

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42

Al-Salem, S. M., M. H. Behbehani, H. J. Karam, S. F. Al-Rowaih, and F. M. Asiri. "On the Kinetics of Degradation Reaction Determined Post Accelerated Weathering of Polyolefin Plastic Waste Blends." International Journal of Environmental Research and Public Health 16, no. 3 (January 30, 2019): 395. http://dx.doi.org/10.3390/ijerph16030395.

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Polyolefin (PO) polymers constitute the majority of consumer plastic commodities. The reliance on such materials make it near imposable to avoid touching one in any given day. Therefore, the accumulation of plastic solid waste (PSW) in developed and developing societies alike requires immediate attention to manage and valorize this type of waste. In this work, PSW originating from real life sources and virgin linear low-density polyethylene (LLDPE) films were compounded in a mechanical recycling effort. The recycled blends constituted up to 100% (by weight) of the waste material. Accelerated weathering (aging) was conducted on the blends, reaching threshold limit of exposure to study the major changes occurring on the recycled blends. Thermogravimetry and differential scanning calorimetry (DSC) were used to determine their characteristics and applicability for future recycling using thermo-chemical treatment (TCT) methods. Analytical solution methods following the international committee of thermal analysis and calorimetry (ICTAC) were followed in conducting the measurements and kinetic calculations alike. A novel analytical mathematical solution model is also introduced to determine both the pre-exponential factor (Ao) and apparent activation energy (Ea) of the degradation reaction. The model proved to be a more accurate analysis tool, and the work in whole enabled the determination of future plans for using such waste components as a feedstock to thermal units.
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43

Yin, Ke, Hanlie Hong, Gordon Jock Churchman, Zhaohui Li, Wen Han, and Chaowen Wang. "Characterisation of the hydroxy-interlayered vermiculite from the weathering of illite in Jiujiang red earth sediments." Soil Research 52, no. 6 (2014): 554. http://dx.doi.org/10.1071/sr14014.

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The clay mineralogy and formation of hydroxy-interlayered vermiculite (HIV) in the Jiujiang red earth sediments were investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and inductively coupled plasma-atomic emission spectrometer (ICP-AES) analyses. The 1.4-nm peak of HIV did not change after Mg2+ saturation and glycol solvation, but it exhibited partial collapse to 1.0 nm after K+ saturation followed by heat treatment at successively higher temperatures. HIV was also characterised by FTIR adsorption bands at ~3485 cm–1 and ~3415 cm–1, which did not change with increasing temperature. DSC analysis revealed that the dehydroxylation of hydroxides in the interlayer of HIV began at ~400°C, and a further dehydroxylation was confirmed by the XRD of the sample heated to ~600°C. The ICP-AES analysis of sodium citrate extracts showed that the Al concentration was higher than that of Fe, indicating that the Al was probably present as hydroxy-Al in the interlayer of HIV. The presence of hydroxy-Al polymers in the interlayer influenced both expandability and thermal properties of HIV clays from Jiujiang red earth sediments.
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44

Douminge, Ludovic, S. Mallarino, X. Feaugas, and J. Bernard. "Following the First Steps of UV Degradation of High Density Polyethylene by Fluorescence Spectroscopy." Defect and Diffusion Forum 289-292 (April 2009): 741–46. http://dx.doi.org/10.4028/www.scientific.net/ddf.289-292.741.

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Ultraviolet radiation is one of the major factors that affect weathering of polymers. Indeed, diffusion of oxygen containing groups [-C-O, C=O and C(=O)O-] into the molecular chains of polymers is particularly enhanced by UV irradiation in air, thus entailing structural and chemical changes such as polymeric chain breaking, cross-linking and oxidation. The goal of this study is to predict the photo-chemical ageing of polymers upon UV radiation through a non destructive method: fluorescence spectroscopy. In the case of high density polyethylene (HDPE) the addition of fluorophore is required to make it fluorescent. The spectral features of fluorescence are very sensitive to the interactions between the excited molecules and the matrix. In this way, Fourier-Transform InfraRed spectrophotometry (FTIR) and Differential Scanning calorimetry (DSC) have been employed to correlate the fluorescence spectra with the degradation phenomena.
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45

Lee, M. R., P. A. Bland, and G. Graham. "Preparation of TEM samples by focused ion beam (FIB) techniques: applications to the study of clays and phyllosilicates in meteorites." Mineralogical Magazine 67, no. 3 (June 2003): 581–92. http://dx.doi.org/10.1180/0026461036730119.

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AbstractTransmission electron microscope samples were prepared of ALH 78045 and ALH 88045, two clay-and phyllosilicate-bearing Antarctic meteorites, using argon ion milling and focused ion beam (FIB) techniques. ALH 78045 contains clay- and phyllosilicate-filled veins that have formed by terrestrial weathering of olivine, orthopyroxene and metal. Very narrow (∼10 nm) intragranular clay-filled veins could be observed in the TEM samples prepared by argon ion milling, whereas differential thinning and lack of precision in the location of the electron-transparent areas hindered the study of wider (5 — 15 μm) phyllosilicate-filled intergranular veins. Using the FIB instrument, electron-transparent slices were cut from specific parts of the wider veins and lifted out for TEM study. Results show that these veins are occluded by cronstedtite, a mixed-valence Fe-rich phyllosilicate. This discovery shows that silicates can be both dissolved and precipitated during terrestrial weathering within the Antarctic ice. ALH 88045 is one of a small number of known CM1 carbonaceous chondrites. This meteorite is largely composed of flattened ellipsoidal aggregates of serpentine-group phyllosilicates. To determine the mineralogy and texture of phyllosilicates within specific aggregates, TEM samples were prepared by trenching into the cut edge of a sample using the FIB instrument. Results show that Mg-rich aggregates are composed of lath-shaped serpentine crystals with a ∼0.73 nm basal spacing, which is typical of the products of low temperature aqueous alteration within asteroidal parent bodies. Results of this work demonstrate that the FIB has enormous potential in a number of areas of Earth and planetary science.
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46

Yang, Guo Xiang, Jin Yu Dong, Fa Quan Wu, Dong Wang, and Ji Hong Yang. "Study on High Cutting Slopes with Horizontal Soft-Hard Strata in Three Gorges Reservoir Area." Advanced Materials Research 168-170 (December 2010): 2595–601. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.2595.

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High cutting slopes with nearly horizontal soft-hard alternant strata are widely distributed in three gorges reservoir area, the soft and hard rocks are mainly mud stone and sandstone of Jurassic system. Sliding failure of this kind of slope is also the main geo-hazards in this area. Firstly, this paper analyzed the impact of topography, water as well as the differential weathering and combination characteristics of soft and hard rocks etc. on the sliding failure of slopes; secondly, sliding failure modes of this kind of slope were classified into four types including circular sliding, sliding along the extroversion structural surface, sliding along the mudded intercalation and wedge sliding, they were analyzed combined with case study. And lastly, support methods against the certain failure mode were put forward. The research results are significant to the support and treatment of high cutting slopes in Three gorges area.
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47

Tsirambides, Ananias. "Texture and mineralogical composition of Quaternary terrestrial and marine sediments from Macedonia and Thrace, Greece." Bulletin of the Geological Society of Greece 55, no. 1 (October 23, 2019): 137. http://dx.doi.org/10.12681/bgsg.20628.

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Clastic sediments collected from land and gulfs of Macedonia and Thrace in Greece are examined on the basis of their texture and mineral composition. All terrestrial samples are coarse-grained and poorly sorted, with angular to sub-angular grains. These are mainly composed of quartz and feldspars, followed by micas, calcite and Fe-Mg minerals. Among the clay minerals illite predominates over smectite and smectite over vermiculite (+chlorite+kaolinite). In addition, the interstratified phases illite/smectite, chlorite/vermiculite, and smectite/vermiculite are present in significant amounts in the clay fraction (<2 μm), signifying the incomplete weathering of the primary minerals. Mixing during transportation, flocculation, differential settling processes and organic matter are the main mechanisms for the distribution of the discharged terrigenous load into the North Aegean Gulfs. All gulf bottom samples are coarse to fine grained and medium sorted, and their grains are angular to sub-angular. Quartz and feldspars predominate. In addition, biogenic calcite, micas and various Fe-Mg minerals exist as primary and/or accessory minerals. Among clay minerals, illite predominates over smectite and smectite over kaolinite (+chlorite+vermiculite). Almost in all gulf sediments the interstratified phase illite/smectite is apparent. The presence of feldspars and Fe-Mg minerals, as well as the high content of clay minerals and the polymodal grain-size distribution with angular to sub-angular grains, signify mineralogical and textural immaturity of all the examined sediments, as well as predominance of mild climatic conditions and thus mild weathering processes. The quartz content in these sediments is usually <70%. Therefore, a sedimentation cycle of these materials has not been completed.
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48

López-Suevos, Francisco, and Charles E. Frazier. "The role of resol fortifiers in latex wood adhesives." Holzforschung 60, no. 5 (August 1, 2006): 561–66. http://dx.doi.org/10.1515/hf.2006.093.

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Abstract Static and dynamic rheological analyses using time/temperature equivalence were applied to freestanding poly(vinyl acetate-co-NMA) adhesive films and to wood-bonded films (composites), which were completely dry in all cases. Films and composites were prepared with two types of cross-linking: (1) cross-linking through AlCl3 catalysis of N-methylolacrylamide (NMA) comonomer; and (2) additional cross-linking using a resol phenolic (PF) additive, in addition to AlCl3 catalysis. Rheological experiments revealed that accelerated weathering (AW) significantly modified the mechanical response of films and composites lacking the PF additive. For samples lacking PF fortifier, AW caused a new thermal transition appearing as a major mechanical softening in the long time domain (creep master curves) or in the low-frequency region (dynamic master curves). This new transition correlated to a performance loss found with fracture testing in a previous publication. Here, the static and dynamic rheological data indicated that the AW-induced softening was a reversible transition. Differential scanning calorimetry analysis and the manipulation of physical aging effects demonstrated that the AW-induced softening was a glass transition. The calorimetric weakness and temperature of this transition indicated that it corresponds to the Tg of poly(vinyl alcohol) (PVOH), which is the emulsion polymerization interfacial agent. In contrast, all PF-formulated samples displayed only the base polymer Tg. Therefore, the PF additive prevented weathering effects that lead to PVOH softening. Atomic force and scanning electron microscopy provided visual evidence of the action of PF on PVOH at interparticle boundaries. We suggest that the PF fortifier enhances latex durability through the formation of hydrolytically stable PVOH cross-links at the interparticle boundaries.
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Latos-Brozio, Malgorzata, and Anna Masek. "Biodegradable Polyester Materials Containing Gallates." Polymers 12, no. 3 (March 18, 2020): 677. http://dx.doi.org/10.3390/polym12030677.

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Gallates are widely used as antioxidants in the food and cosmetics industries. The purpose of the study was to obtain pro-ecological materials based on biodegradable polyesters, such as polylactide (PLA) and polyhydroxyalkanoate (PHA), and gallates. Gallates (ethyl, propyl, octyl, and lauryl) have not been used so far in biodegradable polymers as stabilizers and indicators of aging. This manuscript examines the properties of gallates such as antioxidant capacity and thermal stability. This paper also presents the following analyses of polymer materials: specific migration of gallates from polymers, SEM microscopy, differential scanning calorimetry (DSC), wide-angle X-ray diffraction, mechanical properties, surface free energy, and determination of change of color after controlled UV exposure, thermooxidation, and weathering. All gallates showed strong antioxidant properties and good thermal stability. Due to these properties, in particular their high oxidation temperature, gallates can be successfully used as polyester stabilizers. Biodegradable polyesters containing gallates can be an environmentally friendly alternative to petrochemical packaging materials.
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50

Bowden, M. C. B., D. A. Mackay, and N. K. Blood. "A New Survey of Ingleborough Hillfort, North Yorkshire." Proceedings of the Prehistoric Society 55, no. 1 (1989): 267–71. http://dx.doi.org/10.1017/s0079497x00005454.

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Abstract:
A survey of Ingleborough was undertaken by RCHME in the summer of 1988 at the request of the Yorkshire Dales National Park who are concerned by the considerable erosion and damage occurring on the Peak as a result of the popularity of the Three Peaks footpath. This is affecting not only the natural surface of the hill but also the archaeological remains.The summit of Ingleborough, one of the Three Peaks of the Yorkshire Dales, is a gritstone cap overlying the sandstone, shale and limestone beds of the Yoredale Series which, in turn, overlie the Great Scar Limestone. This formation gives Ingleborough its distinctive stepped profile, created by differential weathering, except where glacial drift forms smoother slopes on the flanks (Crutchley 1981, 41–44). The coarse gritstone forms a roughly triangular, plateau-like summit with only a slight rise from the rim to the highest point, at 723 m OD, now occupied by a triangulation pillar and cruciform walkers's shelter.
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