Wax Distribution Research Articles

Caracteres foliares en diez especies neotropicales y argentinas de Canna (Cannaceae, Zingiberales).

Se llevó a cabo un estudio con microscopía de luz y electrónica de barrido (MEB) de los caracteres de la epidermis y de la ontogenia de los estomas en especies neotropicales de Canna (Cannaceae). Se estudiaron la presencia y tipos de indumento, el contorno foliar, los tipos de cera epicuticular, los modelos epidérmicos, el ordenamiento celular típico de epifilos e hipofilos, el espesorde la pared externa de las células epidérmicas y los caracteres de los estomas adultos paracíticos en ejemplares de C. ascendens, C. glauca, C. indica, C. lineata, C. paniculata, C. tandilensis y C. variegatifolia. Los caracteres se correlacionaron con el hábitat de las plantas. La ontogenia estomáticase analizó en dos especies: C. coccinea y C. glauca; se encontraron desarrollos perígenos y mesógenos, éstos no descritos previamente para la familia. El conjunto de los caracteres foliares macroscópicos y los microscópicos resultan diagnósticos en las especies analizadas y por ello, se consideran especialmenteútiles en la determinación de especies de Canna cuando se trabaja con ejemplares en estado vegetativo y sin flores.

Sediment biomarker, bacterial community characterization of high arsenic aquifers in Jianghan Plain, China

Representative biomarkers (e.g., n-alkanes), diversity and microbial community in the aquifers contaminated by high concentration of arsenic (As) in different sediment depth (0–30 m) in Jianghan Plain, Hubei, China, were analyzed to investigate the potential mechanism of As enrichment in groundwater. The concentration of As was abundant in top soil and sand, but not in clay. The analysis of the distribution of n-alkanes, CPI values, and wax to total n-alkane ratio (Wax(n)%) indicated that the organic matter (OM) from fresh terrestrial plants were abundant in the shallow sediment. However, n-alkanes have suffered from significant biodegradation from the depth of 16 m to 30 m. The deposition of fresh terrestrial derived organic matters may facilitate the release of As from sediment to groundwater in the sediment of 0–16 m. However, the petroleum derived organic matters may do the favor to the release of As in the deeper section of borehole (16 m to 30 m). The 16S rRNA gene sequences identification indicated that Acidobacteria, Actinomycetes and Hydrogenophaga are abundant in the sediments with high arsenic. Therefore, microbes and organic matters from different sources may play important roles in arsenic mobilization in the aquifers of the study area.

Leaf waxes in litter and topsoils along a European transect

Abstract. Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C27 alkane and n-C28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C31 and C33 n-alkanes and C32 and C34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C31 + n-C33) / (n-C27 + n-C31 + n-C33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.

Numerical prediction of wax deposition in oil–gas stratified pipe flow

Wax deposition in oil–gas two-phase pipe flow can be a significant flow assurance problem. It becomes complicated when gas phase flow is involved. In this work, a numerical model is proposed for the wax deposition for oil–gas stratified smooth pipe flow. A unidirectional flow numerical model is used to calculate the non-isothermal hydrodynamics, heat and mass transfer. The wax deposit layer is assumed to be a growing porous layer, which caused by the diffusion of wax molecules through a porous medium. The numerical calculation performance is illustrated by the lab-scale flow experiment. The model could give the non-uniformly circumferential distribution of wax deposit on the inner pipe wall, i.e. a crescent shape, and the predicted deposit thickness is shown to increase with an increasing in superficial gas velocity and superficial oil velocity. The trends in the model predictions compare satisfactorily with those from lab-scale experimental results. In addition, it was found that the concave-down configuration of the oil–gas interface must be taken into accounted for the wax deposit. Unfortunately, this has not been taken into account in all previous studies.

Predicting of Parameters Affecting on PE Wax Powder Size Distribution and Shape in Atomization Process

The aim of this work is to study the parameters affecting on the particle size distribution and shape of Polyethylene wax (PE wax) powders in atomization process. Effect of liquid flow rate, melting temperature and air pressure are studied parameters. External mixing two fluid nozzles is used and temperature is controlled at 200˚C to avoid freeze-up within the liquid cap. PE wax is melted at various temperatures from 120˚C to 180˚C and is atomized with air pressures from 1 to 7 bar. Particle size and size distribution are determined by Particle Sizing Unified System (Mastersizer, 2000). Using 1 bar of air pressure, 140˚C of melting temperature and 3.0:1.5 of ALR gives the PE wax powders size that smaller than 200 micron and high bulk density. Moreover, smoothly and silky surface of PE wax powders are obtained.

Non-destructive detection of the wax bloom on European plum during post-harvest handling

Post-harvest handling may disturb the wax bloom of plum, blueberry or grape berry, which constitutes both an external visual (speckled fruit) as well as physiological fruit quality parameter (disturbing the water loss barrier) with the following results:(a)Destructive ESEM analysis showed the wax bloom of European plum to be caused by wax platelets, where the wax is largely re-distributed on handling rather than removed.(b)CIE L* values significantly (p<0.05) decreased from 37.3 to 28.1, indicating a darker plum surface after polishing. The a-value of the plum surfaces increased significantly from 2.35 to 2.86, whereas b-values decreased ca. 2.5-fold from −13.9 to −5.0 after polishing viz the plum surface became more red and less blue.(c)Luster levels (glossiness) detected non-destructively increased by almost 3-fold from 111 (SD+20) to 284 (SD+32) relative units.(d)Analysis of RGB images visualised the relative wax distribution over the fruit surface after polishing, as uneven with a more dense wax coverage at the fruit apex and less at the fruit equator, where the contacts by hand are most frequent.The changes in L and b values, and to a lesser extent in the a-value, luster levels and RGB image analysis may be used as a technical fruit quality parameter as determined non-destructively.

Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films

This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG+wax+PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface.

Understanding the distribution of natural wax in starch–wax films using synchrotron-based FTIR (S-FTIR)

High amylose starch–glycerol (HAG) films were produced incorporating beeswax, candelilla wax and carnauba wax in the presence and absence of Tween-80 in order to determine the distribution of wax in the films during the film formation process. The distribution of these waxes within the film was studied using Synchrotron based Fourier Transform Infrared Spectroscopy (S-FTIR) which provided 2D mapping along the thickness of the film. The incorporation of 5% and 10% wax in HAG films produced randomly distributed wax or wax-rich domains, respectively, within these films. Consequently, the addition of these waxes to HAG increased the surface roughness and hydrophobicity of these films. The addition of Tween-80 caused variations in wax-rich bands within the films. The HAG+carnauba wax+Tween-80 films exhibited domed wax-rich domains displayed with high integrated CH2 absorption value at the interior of the films, rougher surface and higher contact angle values than the other films. The S-FTIR 2D images indicated that the distribution of wax in starch–wax films correlated with the roughness and hydrophobicity of the starch–wax films.

Thermal and mechanical properties of bio-based PCMs encapsulated with nanofibrous structure

An environmentally friendly phase change material (PCM) was successfully prepared by encapsulating natural soy wax into polyurethane (PU) nanofibers using coaxial electrospinning technique. The morphology and the structure of the wax/PU composites were characterized. Thermal behaviors as well as mechanical properties of the composites were also investigated. The results indicated that coaxial electrospinning produced uniform fiber morphology with a core–shell structure and a homogeneous wax distribution throughout the core of the fibers. The soy wax was successfully encapsulated into PU fibers without being miscible with PU fibers. Thermal analysis results show that the enthalpy increases as the wax content increases. The fibrous structures exhibited balanced thermal storage and released properties for thermo-regulating function. The thermal properties were unaltered after 100 heating–cooling cycles, demonstrating that the composite fibers had good thermal stability and reliability. Tensile tests also indicate that the presence of wax enhanced the modulus and lowered the tensile strain.

Study on the phase behavior of asphalt mastic

In order to improve the road performance of asphalt mixture, the phase behavior of asphalt mastic which is the most important component of asphalt mixture was studied. The glass transition temperature (Tg) and glass transition activation energy of asphalt mastic were obtained by the dynamic mechanics analysis (DMA) method, and the effect of fillers on the distribution of wax in asphalt was studied by the differential scanning calorimetry (DSC). The effect of fillers on temperature sensitivity of asphalt mastic was studied through Brookfield viscometer. The phase separation of asphalt mastic and the applicability of time temperature superposition principle (TTSP) on asphalt mastic were studied by van Gurp-Palmen (vGP) plot. The results show that the faster the load frequency is, the higher Tg is, and the addition of fillers can increase Tg and glass transition activation energy. The distribution of wax in asphalt is discrete, and fillers have little impact on it. The addition of fillers can improve the temperature sensitivity of asphalt mastic, and the effect order is as follows: granite>andesite>limestone. The TTSP is effective for virgin asphalt at any temperature because of its homogeneity, but it is not effective for modified asphalt when the temperature is higher than 45°C because of its phase separation, and the addition of fillers can promote phase separation occur in modified asphalt.

Distribution and stable isotopes of plant wax derived n-alkanes in lacustrine, fluvial and marine surface sediments along an Eastern Italian transect and their potential to reconstruct the hydrological cycle

Reconstructing terrestrial water budgets is of prime importance for understanding past climate and environment. To shed more light on how plant-wax derived n-alkanes may be used for this purpose we investigated the distribution and stable isotopic compositions of hydrogen (δD) and carbon (δ13C) of plant-wax derived n-C29 and -C31 alkanes in terrestrial, coastal and offshore surface sediments in relation to hydrology along a NW–SE transect east of the Italian Apennines from the Po River to the Eastern Gulf of Taranto. The plant wax average chain length increases southward and may relate to increasing temperature and/or aridity. The plant wax δD of the terrestrial and coastal samples also increases southward and mainly reflects changes in the δD of precipitation. The δ13C of plant waxes is primarily interpreted in terms of C3 vegetation changes rather than varying contributions by C4 plants. The plant wax δ13C–δD composition of the Po River and Apennine rivers differs considerably from that in southern Italy, and suggests a mainly southern source for plant waxes in marine sediments of the Gulf of Taranto. This calibration provides a basis for the reconstruction of past changes in the Italian water balance and n-alkane source areas.

Chemotaxonomic significance of n-alkane distributions from leaf wax in genus of Sinojackia species (Styracaceae)

Sinojackia is a Chinese endemic genus of Styracaceae, containing eight species. The taxonomy of one species, Sinojackia dolichocarpa (≡ Changiostyrax dolichocarpa ), is controversial. Here we investigate the distribution of leaf wax n -alkanes to clarify the chemotaxonomic position of S. dolichocarpa . Leaf samples of six Sinojackia species from Wuhan Botanical Garden in central China were collected during April, July, and December in 2010 to capture different developmental stages of the epicuticular waxes. Our results show that the waxes of S. dolichocarpa differ from the other five species by having a lower abundance of n C 31 but a higher abundance of n C 33 . Although developmental variations of n -alkane distributions were observed during the sampling periods, cluster analysis based on the percentages of n -alkanes from C 27 to C 33 separates S. dolichocarpa from the other Sinojackia species. Based on these finding, we suggest S. dolichocarpa is a species independent of the Sinojackia genus. ► Leaf samples of six Sinojackia species were collected in three months (April, July and December) in 2010. ► Temporal and inter-species variations of n -alkane distributions were observed during sampling periods. ► The results suggested that significant differentiation occurred among the genus. ► n -alkane distributions provide evidence to support that Sinojackia dolichocarpa is a species independent of the Sinojackia genus.

Effect of Carbon Number Distribution of Wax on the Yield Stress of Waxy Oil Gels

Wax deposition is one of the most important problems in flow assurance of petroleum pipelines. Pigs are commonly employed for the removal of wax deposit (actually a wax–oil gel consisting of liquid oil and solid wax particles) on the pipe wall. Understanding of the wax deposit strength, which may be a function of the carbon number distribution of wax, assists in preventing the pig from getting stuck in the pipeline. This study focuses on the effect of the carbon number distribution of wax on the yield stress of waxy oil gels. Waxes with different carbon number distribution were dissolved into a crude oil to prepare the model oils. The vane method was used to determine the yield stress of waxy oil gels formed under quiescent or shear conditions, in which an applied shear stress was maintained during the process of cooling and isothermal holding. The results showed that the yield stresses dramatically decrease with increase of average carbon number of wax regardless of the quiescent or shear conditions. How...

Waxy Oil Pipeline Transportation through Cold Flow Technology: Rheological and Pressure Drop Analyses

The cold flow of waxy slurries has been recently appointed as a potential method to avoid or partially reduce the wax deposition in a waxy oil transportation pipeline (Merino-Garcia, D. and Correra, S.Pet. Sci. Technol.2008, 26, 446−459). An experimental investigation on a large flow loop with rough pipes (inner diameter = 5.08 cm; L ∼ 70 m) was then carried out with the aim to study the cold flow of waxy slurries. The wax slurry was constituted by a commercial paraffin wax distribution in n-decane, previously characterized from a rheological point of view. The influences of the wax concentration and flow rates on the pressure drop were investigated by loop runs. A comparison between the experimental pressure drop and modeling results was carried out by investigating friction factor correlations suitable for waxy slurry flow. Furthermore, the same set of data was used, regardless of the rheological characterization, to assess the rheological behavior of the suspensions. This second approach has allowed ev...

A Survey of Paragenetic and Associated Resources in Lignite of China

Lignite is abundant in natural resource in china, and its production increases year by year. However, the accompanying resources in lignite have not been used effectively and comprehensively such as lignite wax, humic acid and coalbed methane (CBM), etc. We analyzed distribution and characteristics of lignite wax, humic acid and CBM in our country, and estimated its resources in the lignite main distribution area. To be specific, total resource extent of lignite wax is approximate 33.21×108t; humic acid is 623.09×108t and that of CBM is about 14000×108m3.

Encapsulation of bio-based PCM with coaxial electrospun ultrafine fibers

In this study, bio-based phase change material (bio-PCM) was successfully encapsulated in ultrafine fibers via coaxial electrospinning technique. Natural soy wax was used as the bio-PCM for thermal storage and Polyurethane (PU) was used as the shell material for encapsulation. The bio-PCM fibers were characterized by environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and X-ray Diffraction (XRD). The results indicate that coaxial electrospinning resulted in a uniform fiber morphology with a core-shell structure, and a homogeneous wax distribution throughout the core of the fibers. Thermal analysis results show that the enthalpy increases with wax content. The fibrous structures exhibited balanced thermal storage and releasing properties for thermo-regulating functions. The thermal properties were unaltered after 100 heating-cooling test cycles, demonstrating that the composite fibers have good thermal stability and reliability.

The interactions between wax and UF resin in medium density fibreboard

Through the use of fluorescently labelled paraffin wax and UF resin, fluorescence microscopy has been used to simultaneously visualise wax and resin components on medium density fibreboard (MDF) fibre. To simulate differing application methods, the wax and resin were applied to fibre either separately or as a mixture. Visualisation on unpressed fibre and in panels suggests the application order can lead to differing wax-resin behaviours and how each interact with fibre. Both qualitative and quantitative analyses of wax and resin distribution on fibre established that the main differences in behaviours were due to wax and occur on pressing. Applying wax first to fibre led to wax droplet agglomeration in panels whereas applying wax after resin or as a mixture appeared to allow wax to be retained as relatively smaller droplets within the resin matrix. This also manifested itself in differences in wax overlap with resin in panels, where a relatively low overlap was observed when applying wax first, despite a substantially higher overlap in unpressed fibre. Application of wax after resin or as a mixture resulted in the wax generally staying with the resin. The observed differences in wax distribution were also correlated with panel cold water soak properties.

Resin and wax distribution and mobility during medium density fibreboard manufacture

Fluorescently labelled UF resin and paraffin wax have been used at a medium density fibreboard (MDF) production facility to characterise resin and wax distribution and mobility on MDF fibre and panels. The major findings from these comprehensive mill-scale trials have been the mobility of UF resin on fibre throughout the MDF process, while wax mobility occurs only on panel pressing. Complex interactions exist between resin distribution and wood fibre wall penetration which collectively provide evidence for three-dimensional resin movement on fibre through the production process. Fibre exiting the blowline had relatively high rates of resin coverage with resin droplet sizes dominated by the process of resin smearing through fibre-fibre contacts. On passing through the dryer resin coverage of fibre reduces, before increasing again on panel pressing. Wax distribution on unpressed fibre was dependent on the mode of application with emulsion and slack wax addition at the refiner being relatively similar, but differing to emulsified wax added via the blowline. On pressing, wax distribution in panels was distinguished by wax type, and was independent of the addition points.

Leaf epidermal characteristics of Cissampelos L. (Menispermaceae) species from Northeastern Brazil

The morphological similarities among the species of Cissampelos are remarkable and the difficult to distinguish them as well. This article presents a comparative anatomical study of the leaves of common Northeastern Brazilian species of Cissampelos, carried out using light and scanning electron microscopy. The leaf epidermal was studied to obtain data on epidermal characteristics and to evaluate their taxonomic significance. As results, some micromorphological characters on the leaf epidermal like the cuticular waxes, the presence of papillae in epidermis and nonglandular trichomes, the anticlinal walls epidermal cells, the distribution, density and type of trichomes, and also the type and distribution of epicuticular wax proved to be the most useful characteristics to distinguish the species in taxonomic studies.

Morphology of wax modified coil coatings without and with pigmentation

Wax modified coil coatings without and with white pigmentation were analyzed by optical light microscopy, Raman spectroscopy and Atomic Force Microscopy. By optical light and Raman microscopy dispersed spherical wax domains in the micrometer range were ascertained on the surface and within the bulk of the coatings. By the combined Atomic Force microscopical and Raman spectroscopical approach it was possible to detect resin and pigment residues in the lubricant features with diameters above 2 μm. Vice versa indications for wax inclusions with diameters below 2 μm in the matrix and rather thin wax layers expanding from the spherical lubricant domains onto the surface were obtained. As to the wax distribution evaluated by optical light and Raman microscopy significant differences between clearcoat and white topcoat were detected. The non-pigmented coating exhibited smaller wax features and an inhomogeneous distribution with less wax on the surface.