1,090 research outputs found
Design Theory Manual For ARMORFORM® Erosion Protection Mats
No full text1.0 Determination Of Forces Generated By Moving Water 1 1.1 Forces Due To Flowing Water 1 1.2 Forces Due To Wave Action 8 2.0 Resisting Forces Provided By Erosion Proteetion 11 2.1 ARMORFORM Mat Characteristics 11 2.2 Resisting Forces On Channel Bottom 12 2.3 Resisting Force On Slopes 17 2.4 Additional Resisting Force Given By Anchors 18 3.0 Design Of ARMORFORM Mat Erosion Proteetion 20 3.1 Mats In Channels With Flowing Water 20 3.2 Proteetion Against Wave Action 22 3.3 Design Charts 28KWP-collectio
Supplemental Material - Author gender and text characteristics in contemporary Swedish fiction
No full textSupplemental Material for Author gender and text characteristics in contemporary Swedish fiction by Mats Dahllöf in Language and Literature</p
Supplemental Material - Author gender and text characteristics in contemporary Swedish fiction
No full textSupplemental Material for Author gender and text characteristics in contemporary Swedish fiction by Mats Dahllöf in Language and Literature</p
Short-chain n-alkanes in benthic mats and mosses from the Larsemann Hills, East Antarctica
No full textVariation in leaf colour (green, red and grey) of mosses and lake benthic mats in Antarctica is often linked to water stress and ultraviolet light (UV-B) exposure. Changes in the abundance of organic compounds, such as pectin and phenols, are associated with mechanisms protecting against desiccation and UV radiation. However, the function of n-alkanes, especially against UV radiation, is rarely examined. Here, gas chromatography–mass spectrometry and Fourier-transform infrared spectroscopy analyses were performed to study the variation in n-alkanes in freshwater lake benthic mats and mosses collected from the Larsemann Hills in East Antarctica. Stable isotopes of organic carbon and nitrogen, environmental DNA characterisation and microscopy-based analyses are used to estimate the presence of cyanobacteria, algae and diatoms in moss and benthic mat consortia. Variation in the short-chain (n-C17 to n-C20) versus long-chain (n-C21 to n-C30) n-alkanes in the mosses and benthic mats with their colour were noted. The research links the relative abundance of short-chain n-alkanes to the UV-B exposure and proposes that Antarctic mosses and benthic mats synthesise short-chain n-alkanes for protection against UV-B.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin
Physical properties of a model set of solid, texture-modified foods
No full textThose suffering from swallowing disorders, or dysphagia, require texture-modified foods for safe swallowing. The texture is modified according to the severity of the disorder, as maintained by the guidelines outlining classes of texture-modified foods, ranging from viscous soups to soft, solid foods. As a basis for studies of bolus rheology and oral response of solid texture-modified foods, a set of well-defined, solid foods has been identified and characterized regarding texture and physical properties. Gelled food is compared to both the firmer timbale class and to the corresponding regular food. Foods eaten at room temperature were chosen to avoid temperature effects: bread, cheese, tomato, and the combination into a sandwich. All foods were tested as gel, timbale, and regular food. The texture was determined by compression and penetration tests, thereby showing a decrease in strength (compression stress), stiffness (modulus), and penetration force for increased degree of modification. The moisture content increased with increased degree of modification. The structural change from room to oral temperature was monitored by the complex shear modulus that showed a decrease with increasing temperature. Cheese and the gelatine-based tomato gel showed a distinct melting when the temperature was increased to 37 degrees C. The texture-modified foods were softer and moister in all aspects as compared to the regular foods, which follows the intended modification. The classes for the texture-modified foods were qualitatively comparable to other national classification systems with regard to solid foods, but there is a lack of objective, physics-based classification of texture, especially for solid, texture-modified foods
Bolus rheology of texture‐modified food: Effect of degree of modification
No full textSwallowing disorders, or dysphagia, require an intake of texture-modified foods progressively softer, smoother, and moister depending on the severity of the disorder. Bolus rheology was determined for five healthy subjects for a set of such solid foods regularly given to dysphagia patients. The softest class was gel food, then a smooth timbale which both were compared to the corresponding regular, un-modified food. The foods investigated were bread, cheese, tomato, and the combination as a sandwich, all for the respective texture class: gel, timbale, and regular food. The subjects chewed until ready to swallow and the expectorated bolus was immediately measured for complex shear modulus and viscosity, and moisture and saliva content were determined. Rheology show that texture-modification influenced bolus rheology with decreased viscosity and modulus for increased degree of modification. Also saliva content as well as chews-to-swallow decreased with degree of modification. Overall, the bolus saliva content was lower for the combination (sandwich) than for the individual components. Saliva content was fairly constant irrespective of food moisture content. The phase angle for all boluses was also relatively constant, indicating a similar bolus structure. All boluses of the texture-modified foods showed high extensional viscosity, which is important for bolus cohesiveness. Bolus rheology rather than food texture determines if a food is safe to swallow and the results show that the intended texture-modification is reflected in the flow properties of the respective boluses
Determination of extensional rheological properties by hyperbolic contraction flow
No full textExtensional rheologyy is important for diverse applications such as processing of viscoelastic fluids, mouthfeel of semi-solid foods, cell mitosis and baking, and is also a useful tool for testing the applicability of constitutive equations. Despite the documented influence of extensional rheological properties, it is seldom measured due to experimental difficulties. There are only commercial equipments available for low-viscosity fluids by Capillary Breakup and for polymer melts by Meissner-type winding of ribbons around cylinders. Both methods have limited applicability for medium-viscosity fluids such as foods and other biological systems. Contraction flows are extensively studied and a new test method has been developed based on contraction flow through a hyperbolic nozzle. The method is suitable for medium-viscosity fluids and has been validated by comparison to results from Filament Stretching and Capillary Breakup. The hyperbolic contraction flow method has been used to characterize food and medical systems, distinguish between different products having equal shear behavior, quantify ropy mouth feel and to predict foaming behavior of biopolymers
Recycled carbon fibre mats for interlayer toughening of carbon fibre/epoxy composites
No full textExploring routes for the effective use of recycled carbon fibres (rCFs) is critical to close the loop in the life cycle of carbon fibres. This work demonstrated a potential of using rCFs for interlayer toughening of carbon fibre/epoxy composites. Nonwoven mats based on rCFs and commingled rCFs/Polyphenylene-sulfid (PPS) fibres were used to interlay a laminate, aiming to improve the mode-I and mode-II fracture toughness. The experimental results proved significant enhancements in the interlaminar fracture properties upon interleaving, with the rCF/PPS mats exhibiting a more prominent toughening effectiveness than the rCF mats. For example, the maximum increase in mode-I and mode-II fracture initiation energies of the laminates was 51% and 66%, respectively upon interleaving the rCF mats, and 220% and 105%, respectively by adding the rCFs/PPS mats. The fractography analysis proved that the main toughening mechanisms were fibre debonding and pulling-out for the rCF mats and fibre bridging for the commingled rCFs/PPS mats. The differences in the toughening mechanisms resulted in opposite effects of the interlayer/epoxy adhesion to the fracture toughness, i.e. an improved interlayer/epoxy adhesion increased the toughening effectiveness of the rCF mats, but negatively affected the toughening performance of the rCF/PPS mats.Structural Integrity & CompositesAerospace Manufacturing Technologie
Bioremediation of uranium contaminated waters using microbial mats, 2000
No full textMicrobial mats are complex, layered microbial communities dominated by cyanobacteria. Mats have been used successfully in the bioremediation of Pb, Cd, Cu, Zn, and Mn contaminated water. This study investigated the possible removal through reduction of soluble U( VI) present in the ionic complexed form in the presence of highly carbonated waters (240 mg/L) by microbial mats. Mats developed in the Bioremediation Laboratory at Clark Atlanta University were used in batch and water column studies. Preliminary studies showed optimum uranium uptake was produced by a 1:1:1 ratio of whole microbial mats, predominately cyanobacteria, and two bacterial groups isolated from the mats: Rhodospeudomonas and a mixed anaerobe group, dominated by sulfur reducers. X-ray absorption near-edge structure spectroscopy (XANES) revealed U(VI) was reduced to U(IV). Uranium removal rate was dependent on temperature, nutrients available, photosynthetic and reducing conditions, and amount of bacterial material per volume of solution
Remediation of mining water with cyanobacterial mats, 1992
No full textMicrobial mats, stimulated with ensiled grass clippings, have been developed to seguester heavy metals from contaminated water. Mixed populations of photosynthetic and heterotrophic bacteria, dominated by Oscillatoria, spp. were developed for metal tolerance and intergrated into a durable, self sustaining community of microbes attached to ensiled grass. Microbial components of the mat and water column effectively removed a number of toxic metals and metalloids from contaminated water by precipitation in the cell mass. Three applications of mats have been found to be effective in treating metal contaminated water. (1) Ponds with floating mats deposited metals at the surface removing 90 99% of the test metal. (2) Excised mats sequestered various metals from mixed solution (28 mg/1 per month of Cd). (3) Immobilized mats, composed of microbes attached to glass wool, in treatment systems employing flow through baffles and floater balls, removed 85 90% of the test metal
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