175 research outputs found

    Design, Manufacturing, and Testing of a Variable Stiffness Composite Cylinder

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    Fiber steering is one of the promising capabilities of Automated Fiber Placement (AFP) technology in manufacturing of advanced composite structures with spatially tailored properties. The so-called variable stiffness (VS) composites have considerable scope to outperform their traditionally made constant stiffness (CS) counterparts. However, there are several design and manufacturing challenges to be addressed before practically using them as structural components. In this work we demonstrate the design, manufacturing and testing procedure of a variable stiffness (VS) composite cylinder made by fiber steering. The improved bending-induced buckling performance is the objective of the VS cylinder to be compared with its CS counterpart. The experimental results show that the buckling capacity of the VS cylinder is about 18.5% higher than its CS counterpart

    Discriminative Localized Sparse Representations for Breast Cancer Screening

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    Breast cancer is the most common cancer among women both in developed and developing countries. Early detection and diagnosis of breast cancer may reduce its mortality and improve the quality of life. Computer-aided detection (CADx) and computer-aided diagnosis (CAD) techniques have shown promise for reducing the burden of human expert reading and improve the accuracy and reproducibility of results. Sparse analysis techniques have produced relevant results for representing and recognizing imaging patterns. In this work we propose a method for Label Consistent Spatially Localized Ensemble Sparse Analysis (LC-SLESA). In this work we apply dictionary learning to our block based sparse analysis method to classify breast lesions as benign or malignant. The performance of our method in conjunction with LC-KSVD dictionary learning is evaluated using 10-, 20-, and 30-fold cross validation on the MIAS dataset. Our results indicate that the proposed sparse analyses may be a useful component for breast cancer screening applications

    Constitutive modelling of skin ageing

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    The objective of this chapter is to review the main biomechanical and structural aspects associated with both intrinsic and extrinsic skin ageing, and to present potential research avenues to account for these effects in mathematical and computational models of the skin. This will be illustrated through recent work of the authors which provides a basis to those interested in developing mechanistic constitutive models capturing the mechanobiology of skin across the life course

    Metal-Substituted Microporous Aluminophosphates

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    This chapter aims to present the zeotypes aluminophosphates (AlPOs) as a complementary alternative to zeolites in the isomorphic incorporation of metal ions within all-inorganic microporous frameworks as well as to discuss didactically the catalytic consequences derived from the distinctive features of both frameworks. It does not intend to be a compilation of either all or the most significant publications involving metal-substituted microporous aluminophosphates. Families of AlPOs and zeolites, which include metal ion-substituted variants, are the dominant microporous materials. Both these systems are widely used as catalysts, in particular through aliovalent metal ions substitution. Here, some general description of the synthesis procedures and characterization techniques of the MeAPOs (metal-contained aluminophosphates) is given along with catalytic properties. Next, some illustrative examples of the catalytic possibilities of MeAPOs as catalysts in the transformation of the organic molecules are given. The oxidation of the hardly activated hydrocarbons has probably been the most successful use of AlPOs doped with the divalent transition metal ions Co2+, Mn2+, and Fe2+, whose incorporation in zeolites is disfavoured. The catalytic role of these MeAPOs is rationalized based on the knowledge acquired from a combination of the most advanced characterization techniques. Finally, the importance of the high specificity of the structure-directing agents employed in the preparation of MeAPOs is discussed taking N,N-methyldicyclohexylamine in the synthesis of AFI-structured materials as a driving force. It is shown how such a high specificity could be predicted and how it can open great possibilities in the control of parameters as critical in catalysis as crystal size, inter-and intracrystalline mesoporosity, acidity, redox properties, incorporation of a great variety of heteroatom ions or final environment of the metal site (surrounding it by either P or Al)

    Barriers to Predicting the Mechanisms and Risk Factors of Non-Contact Anterior Cruciate Ligament Injury

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    High incidences of non-contact anterior cruciate ligament (ACL) injury, frequent requirements for ACL reconstruction, and limited understanding of ACL mechanics have engendered considerable interest in quantifying the ACL loading mechanisms. Although some progress has been made to better understand non-contact ACL injuries, information on how and why non-contact ACL injuries occur is still largely unavailable. In other words, research is yet to yield consensus on injury mechanisms and risk factors. Biomechanics, video analysis, and related study approaches have elucidated to some extent how ACL injuries occur. However, these approaches are limited because they provide estimates, rather than precise measurements of knee - and more specifically ACL - kinematics at the time of injury. These study approaches are also limited in their inability to simultaneously capture many of the contributing factors to injury

    Effect of Sodium Chloride Concentrations and Its Foliar Application Time on Quantitative and Qualitative Characteristics of Pomegranate Fruit (Punica granatum L.) CV. “Malas Saveh”

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    Introduction: Pomegranate (Punica granatum L.) belong to Punicaceae family is native to Iran and grown extensively in arid and semi-arid regions worldwide. Pomegranate is also important in human medicine and its components have a wide range of clinical applications. Cracking causes a major fruit loss, which is a serious commercial loss to farmers. Fruit cracking, seems to be a problem that lessens the marketability to a great extent. Fruit cracking is one of the physiological disorders wherever pomegranate trees are grown. It may be due to moisture imbalances as this fruit is very sensitive to variation in soil moisture prolonged drought causes hardening of skin and if this is followed by heavy irrigation the pulp grows then skin grows and cracks. Many factors i.e., climate, soil and irrigation, varieties, pruning, insects and nutrition statues influence the growth and production of fruit trees. Deficiencies of various nutrients are related to soil types, plants and even to various cultivars. Most nutrients are readily fixed in soil having different PH. Plant roots are unable to absorb these nutrients adequately from the dry topsoil. Foliar fertilization is particularly useful under conditions where the absorption of nutrients through the soil and this difficult situation to be present in the nutrients such as calcium. Since the calcium element is needed, so spraying them at the right time is correct way to save the plant requirements. Therefore, a research conducted on effect of sodium chloride concentrations and its foliar application time on quantitative and qualitative characteristics of pomegranate fruit (Punica granatum L.) CV. “Malas Saveh”. Materials and Methods: An experiment conducted at Jarghoyeh, Esfahan, Iran in 2012. The factors were Sodium chloride (0, 5 and 10 g/L) and times of spray (15, 45 and 75 days before harvest). The study was factorial experiment in the base of randomized complete blocks design with three replications. The measured traits were cracking and sun scald percentage, seed dry and fresh weight, total fruit weight, vitamin C and titratable acidity (TA) using titration method, total soluble solids (TSS) using hand refractometer, skin fruit firmness using hand penetrometre, pH using pH meter and dry material. Data analyzed using SAS and MSTAT-C statistical program and means compared using an LSD test (p < 0.05). Results and Discussion: Analysis of variance showed that calcium chloride had significant effect on creaking percentage. Mean comparison was conducted using LSD range test (at 5% level). Sodium chloride decreased cracking percentage compared to control. Different stages of sodium chloride application show significant effect on cracking percentage. Sodium chloride decreased the cracking rate by increasing of its concentrations. Effect of calcium chloride was significant on sun scald. The lowest sun scald occurred inthe second time and the highest in the third time of calcium chloride spraying. The effects of sodium chloride at different stages and concentrations were significant on the total fruit weight and seed fresh weight. The highest total fruit weight and seed fresh weight obtained in the first time and the lowest in the third time of calcium chloride spraying. The effects of sodium chloride at different stages and concentrations were significant on the skin firmness. The highest skin firmness obtained in the third time of calcium chloride spraying and 10 sodium chloride concentrations and the lowest in the first time of calcium chloride spraying and control. The time of calcium chloride spraying had significant effect on total acidity, pH and vitamin C. The highest and lowest fruit total acidity and pH obtained in first and third time of calcium chloride spraying, respectively. However, the highest and lowest fruit vitamin C observed in third and first time of calcium chloride spraying, respectively. Fruits treated with Sodium chloride showed a reduction in vitamin C and fruit firmness, but increased total soluble solids (TSS). In fruit traits increased by higher sodium concentration and earlier spraying time. In addition, later spraying time increased fruit skin firmness conclusion sodium chloride decreased cracking and sun scald percentage Quantitative. Conclusion: In conclusion, higher sodium chloride concentration reduced fruit creaking and sun scald. In addition, earlier time and higher sodium chloride concentration caused improve quantitative fruit traits. Finally, skin firmness increased with higher sodium chloride concentration and later spraying time

    Regulation of the ascorbate-glutathione cycle in wild almond during drought stress

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    In wild species of almond (Prunus spp.), the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR), as well as the levels of ascorbate/glutathione pools and H2O2 were subjected to water deficit and shade conditions. After 60 days of water shortage, the species were subjected to a rewatering treatment. During water recovery, leaves exposed to sunlight and leaves under shade conditions of about 20–35% of environmental irradiance were sampled. After 70 days without irrigation, mean predawn leaf water potential of all the species fell from −0.32 to −2.30 MPa and marked decreases in CO2 uptake and transpiration occurred. The activities of APX, MDHAR, DHAR, and GR increased in relation to the severity of drought stress in all the wild species studied. Generally, APX, MDHAR, DHAR, and GR were down-regulated during the rewatering phase and their activities decreased faster in shaded leaves than in sun-exposed leaves. The levels in total ascorbate, glutathione, and H2O2 were directly related to the increase in drought stress and subsequently decreased during rewatering. The antioxidant response of wild almond species to drought stress limits cellular damage caused by reactive oxygen species during periods of water deficit and may be of key importance for the selection of drought-resistant rootstocks for cultivated almond

    Salt stress induction of some key antioxidant enzymes and metabolites in eight Iranian wild almond species

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    The present work describes the changes in the activities of key antioxidant enzymes and the levels of some metabolites in relation to salt tolerance in eight wild almond species. All the species were exposed to four levels of NaCl (control, 40, 80 and 120 mM). Plant fresh biomass, α-, γ- and Ύ-tocopherol, total soluble proteins, malondialdehyde (MDAeq), H2O2, total phenolics, and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were analyzed in leaves of salt-stressed and non-stressed plants of the eight almond species. In all the species, salt stress significantly enhanced the activities of SOD and POD, levels of total phenolics and γ- and Ύ-tocopherols. High levels of salt stress significantly depressed the levels of total soluble proteins, MDA and CAT activity, while salt stress did not significantly affect leaf H2O2 contents. Regression analysis showed that the relationship between salt levels and total soluble proteins, CAT, γ-tocopherol, MDAeq, SOD and POD were statistically significant. Principal component analysis discriminated the almond species on the basis of their degree of tolerance/sensitivity to saline conditions: Prunus reuteri and P. glauca were ranked as salt tolerant, P. lycioides and P. scoparia as moderately tolerant, and P. communis, P. eleagnifolia , P. arabica and P. orientalis as salt sensitive. The results could be used for selecting salt tolerant genotypes to be used as rootstocks for almond cultivation
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