231 research outputs found

    Surface engineering and vapor phase technologies for coating and functionalizing complex objects and small particles

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    The requirements for materials performance in different areas of application continues to face increased technological, economical and environmental challenges, while considering ever improving materials mechanical, optical, electrical, electrochemical and other functional properties and their combination (multifuntionality). This opens new and exciting opportunities for further development of surface engineering methodologies that allow one to fabricate functional coatings and functionalized surfaces with tailored characteristics. Further progress in this field is only possible when considering a holistic approach in which the desired functions are well understood and closely linked with the materials microstructure and the detailed physical and chemical reactions involved in the processes. This presentation will describe the progress in surface engineering of materials using chemical vapor deposition, physical vapor deposition, and plasma-enhanced chemical vapor deposition of functional coatings. It will particularly focus on the following aspects: a) Effect of surface reactions on the evolution of the coating microstructure during the film growth in different pressure regimes ranging from vacuum to the atmospheric pressure. b) Relationship between the microstructure and the film functional characteristics suitable for different areas of application including optics, aerospace, energy, manufacturing and others. c) Application of the vapor phase deposition techniques to coat complex objects including small particles. The latter one will be illustrated by our recent results on the development of the fluidized bed chemical vapor deposition process. Throughout the presentation, we demonstrate the need for advanced diagnostic techniques suitable for the process and materials control on the nanoscale

    Conformal multilayer coatings on fine silica microspheres by atmospheric pressure fluidized bed chemical vapor deposition

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    Surface properties of fine particles can be tuned through deposition of films or coatings. This approach is an area of science and technology of interest in numerous fields such as catalysis, energy production, microelectronics, optoelectronics, etc. Surface coating of powders can be applied by a dry technique (i.e., the use of a reactive gas phase), so-called chemical vapor deposition (CVD). However, conventional CVD processes cannot provide an efficient conformal deposition while fine particles are considered as substrates. This is due to the fact that mixing of particles, in such a way that their entire surface is exposed to the reactive gas phase, is rather complicated and not often addressed. Therefore, fluidization, as a recognized particle treatment process which meets the requirement of gas–solid contact, can be associated with the gas–solid reactions that are often used in the context of various CVD processes. The combination of such mature techniques, namely fluidized bed chemical vapor deposition (FBCVD) leads to innovative, flexible and cost-effective particle treatment processes [1]. In the present investigation, soda lime spherical particles with a particle size of ca. 27 µm were used as the substrate. Single- and multi-layer depositions composed of TiO2 and SiO2 films were applied to the surface of the particles by the FBCVD at atmospheric pressure, while employing, respectively, titanium and silicon tetrachloride as precursors, and using water as an oxidation agent. TiO2 and SiO2 films were deposited at 300oC and ambient temperatures, respectively. Please click Additional Files below to see the full abstract

    THE EFFECT OF ALTITUDE ON BREAKING SEED DORMANCY AND STIMULATION OF SEED GERMINATION OF PERSIAN HOGWEED (HERACLEUM PERSICUM)

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    Persian hogweed is a odorous perennial herb which has pharmaceutical and fodder values. seed is the main propagation method of this species. A seed analysis test was designed to survey the effects of high altitude on breaking dormancy and germination stimulates of Persian hogweed seeds. For this purpose seeds were collected from three different elevations (1700, 2200, 2700 masl) in Kojoor area. After primary cleanings, germination percent(GP) and germination speed (GS) of each elevation were determined by cold stratification compared to control. According to results control seeds were not germinate then seeds of this species need to treat. Statistical analysis of results showed that there are sensible differences between GP and GS of each elevation. As seeds of higher elevation germinate slower and less than higher elevation but in a longer periods. So changes of elevation is an effective factor on germination characteristics of Persian hogweed seeds which have to be considered for every seed collection and rehabilitation program of this species

    A novel mutation in SEPN1 causing rigid spine muscular dystrophy 1: A Case report

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    Abstract Background Muscular dystrophies are a clinically and genetically heterogeneous group of disorders characterized by variable degrees of progressive muscle degeneration and weakness. There is a wide variability in the age of onset, symptoms and rate of progression in subtypes of these disorders. Herein, we present the results of our study conducted to identify the pathogenic genetic variation involved in our patient affected by rigid spine muscular dystrophy. Case presentation A 14-year-old boy, product of a first-cousin marriage, was enrolled in our study with failure to thrive, fatigue, muscular dystrophy, generalized muscular atrophy, kyphoscoliosis, and flexion contracture of the knees and elbows. Whole-exome sequencing (WES) was carried out on the DNA of the patient to investigate all coding regions and uncovered a novel, homozygous missense mutation in SEPN1 gene (c. 1379 C > T, p.Ser460Phe). This mutation has not been reported before in different public variant databases and also our database (BayanGene), so it is classified as a variation of unknown significance (VUS). Subsequently, it was confirmed that the novel variation was homozygous in our patient and heterozygous in his parents. Different bioinformatics tools showed the damaging effects of the variant on protein. Multiple sequence alignment using BLASTP on ExPASy and WebLogo, revealed the conservation of the mutated residue. Conclusion We reported a novel homozygous mutation in SEPN1 gene that expands our understanding of rigid spine muscular dystrophy. Although bioinformatics analyses of results were in favor of the pathogenicity of the mutation, functional studies are needed to establish the pathogenicity of the variant

    SpikeletFCN: Counting Spikelets from Infield Wheat Crop Images Using Fully Convolutional Networks

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    Currently, crop management through automatic monitoring is growing momentum, but presents various challenges. One key challenge is to quantify yield traits from images captured automatically. Wheat is one of the three major crops in the world with a total demand expected to exceed 850 million tons by 2050. In this paper we attempt estimation of wheat spikelets from high-definition RGB infield images using a fully convolutional model. We propose also the use of transfer learning and segmentation to improve the model. We report cross validated Mean Absolute Error (MAE) and Mean Square Error (MSE) of 53.0, 71.2 respectively on 15 real field images. We produce visualisations which show the good fit of our model to the task. We also concluded that both transfer learning and segmentation lead to a very positive impact for CNN-based models, reducing error by up to 89%, when extracting key traits such as wheat spikelet counts
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