Browsing by Subject "TEXTURE"

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  • Riskila, Elina; Lindqvist, Hannakaisa; Muinonen, Karri (2021)
    Atmospheric ice crystals scatter sunlight, affecting Earth's climate through the radiation properties of cirrus clouds. Naturally occurring surface roughness and its effect on the scattering properties of ice crystals remain largely unknown. Scattering by ice crystals with rough surfaces is studied by placing a finite, thin surface-roughness element on an infinitely large, planar vacuum-ice boundary. The elements are generated using a statistical model based on fractional Brownian motion. The horizontal roughness scale is described by the Hurst exponent Hand the vertical roughness scale with the root-mean-square roughness parameter R-q. The computations are performed with the surface mode of the Discrete Dipole Approximation software ADDA (version 1.34b). Several incident directions for wavelength of 0.5 mu m from both above and below the planar surface are studied. A refractive index for ice m = 1.313 + i5.889 x10(-10) is used throughout the computations. Results are averaged over ten rough surface realizations for a specific H, R-q-pair. Scattering by the rough elements is compared to that by the corresponding smooth elements. The rougher the element is, the more of the scattered intensity is transmitted through the surface. The rough elements have distinctively smoother angular distributions for the degree of linear polarization than their smooth counterparts. Also, it is found that while roughness itself affects polarization, the exact surface morphology does not seem to have a significant effect. The vertical roughness scale R-q has a larger effect on the light scattering results than the horizontal scale H. Enhanced angular scattering is detected in directions nearly parallel to the vacuum-ice boundary within the ice medium. The phenomenon is explained with a strong internal reflection mechanism. The model for surface roughness, along with the light scattering methodology used here, could be incorporated into geometric optics ray-tracing computations for large ice crystals and other particles. (C) 2021 The Authors. Published by Elsevier Ltd.
  • Strani, Flavia; Profico, Antonio; Manzi, Giorgio; Pushkina, Diana; Raia, Pasquale; Sardella, Raffaele; DeMiguel, Daniel (2018)
    Mastication of dietary items with different mechanical properties leaves distinctive microscopic marks on the surface of tooth enamel. The inspection of such marks (dental microwear analysis) is informative about the dietary habitus in fossil as well as in modern species. Dental microwear analysis relies on the morphology, abundance, direction, and distribution of these microscopic marks. We present a new freely available software implementation, MicroWeaR, that, compared to traditional dental microwear tools, allows more rapid, observer error free, and inexpensive quantification and classification of all the microscopic marks (also including for the first time different subtypes of scars). Classification parameters and graphical rendering of the output are fully settable by the user. MicroWeaR includes functions to (a) sample the marks, (b) classify features into categories as pits or scratches and then into their respective subcategories (large pits, coarse scratches, etc.), (c) generate an output table with summary information, and (d) obtain a visual surface-map where marks are highlighted. We provide a tutorial to reproduce the steps required to perform microwear analysis and to test tool functionalities. Then, we present two case studies to illustrate how MicroWeaR works. The first regards a Miocene great ape obtained from through environmental scanning electron microscope, and other a Pleistocene cervid acquired by a stereomicroscope.
  • Wang, Hang; Luo, Yongkang; Ertbjerg, Per (2017)
    Minced beef was stored for 8 days and myofibrillar protein (MP) was extracted to investigate the effect of oxygen concentration (0, 20, 40, 60, and 80%) in modified atmosphere packaging (MAP) on heat-induced gel properties. Compression force of gels was lower when prepared from beef packaged in 0% oxygen, intermediate in 20 to 60% oxygen and greater in 80% oxygen. Total water loss of gels prepared from beef packaged with oxygen (20-80%) was higher and rheology measurements presented higher G' and G '' values. Additionally, gels from beef packaged without oxygen exhibited higher J (t) values during creep and recovery tests, demonstrating that oxygen exposure of meat during storage in MAP affect MP in such a way that heat-induced protein gels alter their characteristics. Generally, storage with oxygen in MAP resulted in stronger and more elastic MP gels, which was observed already at a relative low oxygen concentration of 20%. (C) 2017 Elsevier Ltd. All rights reserved.
  • Muukkonen, Ilkka; Kilpeläinen, Markku; Turkkila, Roosa; Saarela, Toni; Salmela, Viljami (2022)
    Previous composite face studies have shown that an unattended face half that differs in identity or in expression from the attended face half distracts face perception. These studies have typically not controlled for the amount of information in different face halves. We investigated feature integration while participants discriminated angry and happy expressions. The stimuli were scaled using individual thresholds to control the expression strength in face halves. In the first experiment, we varied the relative amount of information in upper and lower parts. In the second experiment, participants tried to ignore one half of the face, which was either congruent or incongruent with the attended half. We found both beneficial and obligatory integration of face halves. A robust face composite effect was found both when attending eyes or mouth, and both for congruent and incongruent expressions, suggesting similar processing of face halves when the amount of information is controlled for.
  • Kantanen, Katja Annika; Oksanen, Anni; Edelmann, Minnamari; Suhonen, Heikki; Sontag-Strohm, Tuula; Piironen, Vieno; Ramos-Diaz, Jose Martin; Jouppila, Kirsi (2022)
    Faba bean is a potential ingredient due to its high protein yield and its possible cultivation in colder climate regions. In this study, meat analogues made from faba bean protein isolate (FPI) and concentrate (FPC) blends were produced using high moisture extrusion. The aim of this study was to investigate the effect of the FPI content (FPIc), feed water content (FWC), and temperature of the long cooling die (LT) during extrusion on the mechanical and physicochemical properties as well as on the structure of the meat analogues. Increased FPIc resulted in higher values in hardness, gumminess, chewiness, and cutting strengths as well as in darker colour and decreased water absorption capacity. The effect of increased FWC on these properties was weaker and the opposite. Images from microtomography revealed that higher FPIc led to a less organised fibrous structure. In conclusion, fibrous structures can be achieved by utilising a mixture of faba bean protein ingredients, and a higher FPC content seemed to promote fibre formation in the meat analogue.
  • Pulkkinen, Marjo; Coda, Rossana; Lampi, Anna-Maija; Varis, Jutta; Katina, Kati; Piironen, Vieno (2019)
    Vicine and convicine may be removed from faba bean by hydrolysis to the corresponding aglycones, divicine and isouramil. For total elimination of their toxicity, further degradation of the aglycones should be shown. The aim of the study was to investigate hydrolysis of vicine and convicine using the enzymatic activity in faba bean in flour suspensions and selected lactic acid bacteria used as starters for faba bean fermentation. In addition, the effect of acidity on the stability of vicine and convicine was investigated. Sourdoughs were used in a baking process to obtain breads as final products. Vicine, convicine, and their aglycones were analyzed using reversed phase high pressure liquid chromatography with UV detection (RP-HPLC-UV). Incubation of the suspensions showed rather small vicine and convicine losses. Acidity itself did not cause losses under the conditions studied, apart from that of convicine at low pH. In sourdough fermentation with strains of Lactobacillus plantarum and Pediococcus pentosaceus, losses of vicine and convicine were dependent on the fermentation temperature and the β-glucosidase activity of the starter. Compared to fermentation at 20 °C, more intense acidification at 25 °C resulted in decrease of vicine up to 85% and convicine up to 47%. Levels of vicine and convicine in breads were comparable to levels in sourdoughs. Furthermore, the aglycones were not detected from breads.
  • Soinne, Helena; Keskinen, Riikka; Räty, Mari; Kanerva, Sanna; Turtola, Eila; Kaseva, Janne; Nuutinen, Visa; Simojoki, Asko; Salo, Tapio (2021)
    To achieve appropriate yield levels, inherent nitrogen (N) supply and biological N fixation are often complemented by fertilization. To avoid economic losses and negative environmental impacts due to over-application of N fertilizer, estimation of the inherent N supply is critical. We aimed to identify the roles of soil texture and organic matter in N mineralization and yield levels attained in cereal cultivation with or without N fertilization in boreal mineral soils. First, the net N mineralization and soil respiration were measured by laboratory incubation with soil samples varying in clay and organic carbon (C) contents. Secondly, to estimate the inherent soil N supply under field conditions, both unfertilized and fertilized cereal yields were measured in fields on clay soils (clay 30-78%) and coarse-textured soils (clay 0-28%). In clay soils (C 2.5-9.0%), both the net N mineralization and the cereal yields (without and with fertilization) decreased with increasing clay/C ratio. Moreover, in soils with high clay/C ratio, the agronomic N use efficiency (additional yield per kg of fertilizer N) varied considerably, indicating the presence of growth limitations other than N. In coarse-textured soils, the yield increase attained by fertilization increased with increasing organic C. Our results indicate that for clay soils in a cool and humid climate, the higher the clay content, the more organic C is needed to produce reasonable yields and to ensure efficient use of added nutrients without high N losses to the environment. For coarse soils having a rather high mean organic C of 2.3%, the organic C appeared to improve agronomic N use efficiency. For farmers, simple indicators such as the clay/C ratio or the use of non-N-fertilized control plots may be useful for site-specific adjustment of the rates of N fertilization. Highlights We aimed to identify simple indicators of inherent soil N supply applicable at the farm level. In clay soils, the net N mineralization was found to correlate negatively with the clay/C ratio. In coarse-textured soils, agronomic N use efficiency improved with increasing soil organic C. Clay soils with high clay/C ratio are at risk of low yield levels.