26 research outputs found

    Seed anatomical studies on dormancy and germination in Chamaecrista absus

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    Present study was conducted to analyze the anatomical structure of seed to study the dormancy behaviour in Chamaecrista absus. Seed germination behaviour was also studied after breaking the seed dormancy by artificial seed treatments. The anotamical studies revealed that seed has apical hilar region and seed coat has four layers consisting of outer cuticle, sub cuticle, palisade layer and inner tegma leading to physical dormancy. Outer cuticle and sub cuticle layers are very hard to break naturally and hence seeds possess hard seed coat dormancy. This physically hard seed coat should be made soft to enhance germination. Studies to break dormancy were conducted involving treatments like hot water, hormones and in combinations of both. The results revealed that seeds dipped in boiling water made inner layers permeable for water absorption in hilar region and thus germination enhanced. In specific seeds treated with boiling water for 5 minutes recorded higher germination (82 %) over untreated control (26 %). . Other artificial treatments with hormones gibberellic acid (33 % ) and ethrel (34 % ) did not enhanced the germination significantly over control. C. absus has hard coat dormancy and can be overcame by treating seeds with boiling water treatment

    Experiments and simulations on a cold-flow blast furnace hearth model

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    The blast furnace hearth plays an important role in the operational stability and lifetime of the reactor. The quasi-stagnant bed of coke particles termed the deadman undergoes complex interaction with the flowing hot metal, and remains largely ill-understood. In this work, a cold model blast furnace hearth is presented, and studied using both numerical and experimental techniques. Magnetic Particle Tracking (MPT) is used to investigate the individual particle behaviour within the cylindrical, opaque bed. At high liquid holdup, the particle bed was found to alternate between floating and sitting states, following the liquid level during the tapping and filling cycle. This bed motion was found to induce a migration of particles, thereby slowly renewing the deadman. The rate of horizontal migration increases with the vertical bed amplitude, and the renewal of particles is concentrated around the opening of the tap hole. No direct influence of the coke-free space on the tapping rate was found in these experiments. Instead, the disturbance of the packing in front of the tap hole was observed to lead to a higher tapping rate. Additionally, a coupled numerical framework is presented, in which Computational Fluid Dynamics (CFD), the Volume of Fluid (VOF) method and the Discrete Element Method (DEM) are combined. A simulation set-up is presented which closely replicates the experimental conditions. The position and movement of the floating bed are found to be well-predicted by the VOF/CFD-DEM model. Particle trajectories are presented, and migration of particles within the deadman is observed. Alongside the particle motion, the liquid flow pattern during draining of the vessel is visualised. It is concluded that a coke-free space underneath the deadman significantly impacts the shape of the liquid flow pattern, which affects the erosion processes within the blast furnace hearth.</p

    Series analysis for the flow between two stretchable disks

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    In this paper, we present the semi-analytical/semi-numerical solution of an axis-symmetric flow between two coaxial infinite stretching disks. The governing momentum equations in cylindrical co-ordinates are reduced to fourth order nonlinear ordinary differential equation (NODE) with the relevant boundary conditions. The resulting nonlinear boundary value problem is solved by using Computer Extended Series Solution (CESS) and Homotopy Analysis Method (HAM). The effects of Reynolds number R and disk stretching parameter Îł are discussed in detail. The resulting solutions are compared with the earlier numerical findings. The above methods admit a desired accuracy and the results are presented in the form of graphs. The validity of the series solution is extended to a much larger values of R up to infinity. Further, the variations of shear stress and pressure parameter as a functions of R and Îł are analyzed. For very large R, the governing equation reduces to third order NODE with infinite boundary is solved by using Dirichlet series and the solution is compared with the numerical findings

    Prevalence of subclinical thyroid disorders in type 2 diabetes mellitus

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    Background: Subclinical thyroid disorders usually do not produce symptoms of thyroid disease until they turn into over thyroid disease. Thyroid disease is more common in people with diabetes mellitus than in the general population and it is important to detect thyroid disorder before its clinical manifestation. Subclinical hypothyroidism (SCH) can produce dyslipidemia, obesity thus resulting increased predisposition to coronary artery disease. Subclinical hyperthyroidism can aggravate hyperglycemia and impair blood sugar control. Objectives: Our objective is to determine the prevalence of subclinical thyroid disorders in patients with type 2 diabetes mellitus (T2DM) and to analyze the clinical and metabolic profile of patients with this dual endocrine disorder. Methods and Results: One hundred consecutive type 2 diabetic patients without clinical manifestations of thyroid disorders were screened for SCH and subclinical hyperthyroidism using serum free T 3 , free T 4 and thyroid stimulating hormone (TSH) levels. Individuals of subclinical thyroid disease were further screened for thyroperoxidase (TPO) antibodies. SCH was detected in 13% of type 2 diabetic patients and none had subclinical hyperthyroidism in our study. SCH was common among females with type 2 diabetes (84.6%). Elevated TPO antibody levels were present in 84.6% SCH patients. Diabetic retinopathy among SCH patients showed significant association with higher serum TSH levels. Left ventricular diastolic dysfunction was present in 30.8% of SCH patients. Conclusion: SCH is common among type 2 diabetic patients, especially in females. It is most commonly secondary to autoimmune thyroid disease. Microvascular complications are commonly observed in this group of patients with dual endocrinal disorder and treating physician should be aware of the impact and should routinely screen SCH to prevent complications

    Experiments and simulations on a cold-flow blast furnace hearth model

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    The blast furnace hearth plays an important role in the operational stability and lifetime of the reactor. The quasi-stagnant bed of coke particles termed the deadman undergoes complex interaction with the flowing hot metal, and remains largely ill-understood. In this work, a cold model blast furnace hearth is presented, and studied using both numerical and experimental techniques. Magnetic Particle Tracking (MPT) is used to investigate the individual particle behaviour within the cylindrical, opaque bed. At high liquid holdup, the particle bed was found to alternate between floating and sitting states, following the liquid level during the tapping and filling cycle. This bed motion was found to induce a migration of particles, thereby slowly renewing the deadman. The rate of horizontal migration increases with the vertical bed amplitude, and the renewal of particles is concentrated around the opening of the tap hole. No direct influence of the coke-free space on the tapping rate was found in these experiments. Instead, the disturbance of the packing in front of the tap hole was observed to lead to a higher tapping rate. Additionally, a coupled numerical framework is presented, in which Computational Fluid Dynamics (CFD), the Volume of Fluid (VOF) method and the Discrete Element Method (DEM) are combined. A simulation set-up is presented which closely replicates the experimental conditions. The position and movement of the floating bed are found to be well-predicted by the VOF/CFD-DEM model. Particle trajectories are presented, and migration of particles within the deadman is observed. Alongside the particle motion, the liquid flow pattern during draining of the vessel is visualised. It is concluded that a coke-free space underneath the deadman significantly impacts the shape of the liquid flow pattern, which affects the erosion processes within the blast furnace hearth

    Seminal plasma and its effect on ruminant spermatozoa during processing

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    Seminal plasma can both inhibit and stimulate sperm function, making its use as a supportive medium somewhat contradictory. These effects are directed by the multifunctional action of numerous inorganic and organic components, but it is the direct association of seminal plasma proteins with the sperm membrane that is thought to exert the most significant response. In vitro handling of spermatozoa in preparation for artificial insemination may involve washing, dilution, cooling, freezing, re-warming and sex-sorting. These processes can alter proteins of the sperm surface and reduce seminal plasma in the sperm environment. This, among other factors, may destabilize the sperm membrane and reduce the fertilizable lifespan of spermatozoa. Such handling-induced damage may be prevented or reversed through supplementation of seminal plasma, but the effectiveness of this technique differs with species, and the source and subsequent treatment of both spermatozoa and seminal plasma. Seminal plasma appears to act as a protective medium during in vitro processing of ram spermatozoa, but this does not appear to be the case for bull spermatozoa. The reasons for this divergent effect will be discussed with particular emphasis on the influence of the major proteins of ruminant seminal plasma, known as BSP proteins. The biochemical and biophysical properties of these proteins are well documented, and this information has provided greater insight into the signalling pathways of capacitation and the protective action of extender components
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