1,170 research outputs found
The effect of foliar application of methanol on productivity and fruit quality of grapevine cv. Flame Seedless
Field experiments were conducted in 2002 and 2003 on 6-year-old grapevine cv. Flame Seedless. The content of chlorophyll a and b, carotenoids and total carbohydrates increased after methanol application. Foliar application of aqueous methanol was very effective increasing the number of leaves per shoot and leaf area. Furthermore, 30 % methanol increased significantly the number of stomata of developing leaves at the first application time (shoot length: 20-30 cm) while 10, 30, 40 and 50 % methanol solutions were more effective at the second application date (prebloom). Increasing the chlorophyll content, the leaf area and the number of stomata per unit leaf area by methanol application increased net productivity of vines. There was a highly significant positive correlation between total yield, chlorophyll and carbohydrates content. Generally, all methanol treatments significantly increased length and diameter of shoots and internode length at both application dates. Application of methanol increased total soluble solids (TSS), the TSS/acid ratio and total anthocyanins in berry skins but decreased total acidity. Most significant effects were obtained by spraying 30 % methanol at the two application dates.
Optimasi Parameter Permesinan Terhadap Waktu Proses Pada Pemrograman Cnc Milling Dengan Berbasis Cad/cam
The milling process is one of many machining processes for manufacturing component. The length of time in the process of milling machining is influenced by selection and design of machining parameters including cutting speed, feed rate and depth of cut. The purpose of this study to know the influence of cutting speed, feed rate and depth of cut as independent variables versus operation time at CNC milling process as dependent variables. Each independent variable consists of three level of factors; low, medium and high.Time machining process is measured from operation time simulation program, feed cut length and rapid traverse length. The results of statistically from software simulation MasterCam X Milling, then do the comparison to CNC Milling machine. The data from experiments was statistically analyzed by ANOVA and Regression methods by software Minitab 16.Results show that the greater feed rate and depth of cut shorten the operation time of machinery, whereas cutting speed is not a significant influence. The depth of cut has the highest contribution to the value of 49.56%, followed by feed rate 43% and cutting speed 0.92%. Optimal time of machining process total is 71.92 minutes, with machining parameter on the condition cutting speed is 75360 mm/minutes, the feed rate is 800 mm/minutes and depth of cut = 1 mm. Results of comparison time machining process in software Mastercam X milling with CNC Milling machine indicates there is the difference not significant with the value of 0,35%
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Geothermal based hybrid energy systems, toward eco-friendly energy approaches
Geothermal Energy is a very attractive source of naturally-occurring green renewable energy. Exploiting this natural resource is straightforward and causes almost no ill effects to the environment. But, while geothermal does not suffer the intermittence of other renewable sources, its extraction efficiency is fairly modest as compared to other sources. As a result, there has been significant interest recently in hybrid systems that integrate geothermal and other forms of energy to increase the output efficiency. This work will survey the different possible integrations involving geothermal energy. A review of the literature shows that the most common hybrid systems implementation involve the integration of geothermal with solar (45% of systems) followed by the integration of a cooling tower into the geothermal system (30% of systems). This work will also investigate the applications for geothermal hybrids and show that 44% of systems are designed for heating applications. Another 44% are used for cooling while only 12% are designed for electrical power generation. Complexity of control remains as the main obstacle facing hybrid multi-source energy systems including those involving geothermal energy
Actively Learning Reinforcement Learning: A Stochastic Optimal Control Approach
In this paper we provide a framework to cope with two problems: (i) the
fragility of reinforcement learning due to modeling uncertainties because of
the mismatch between controlled laboratory/simulation and real-world conditions
and (ii) the prohibitive computational cost of stochastic optimal control. We
approach both problems by using reinforcement learning to solve the stochastic
dynamic programming equation. The resulting reinforcement learning controller
is safe with respect to several types of constraints and it can actively learn
about the modeling uncertainties. Unlike exploration and exploitation, probing
and safety are employed automatically by the controller itself, resulting
real-time learning. A simulation example demonstrates the efficacy of the
proposed approach
Histological, immunohistochemical and ultrastructural study of secondary compressed spinal cord injury in a rat model
Introduction. Spinal cord injury (SCI) is a life-disrupting condition in which the first few days are the most critical. Secondary conditions remain the main causes of death for people with SCI. The response of different cell types to SCI and their role at different times in the progression of secondary degeneration are not well understood. The aim of this study was to study the histopathological changes of compressed spinal cord injury (CSCI) in a rat model.
Material and methods. Forty adult male Sprague-Dawley rats were divided into four groups. In group I, the rats were left without any surgical intervention (control). In group II, the rats were subjected to laminectomy without spinal cord compression (sham-operated). In group III, the rats were sacrificed one day after CSCI. In group IV, the rats were sacrificed seven days after CSCI. The light microscopy was employed to study the morphology using H&E, osmic acid staining and immunohistochemistry to detect glial fibrillary acidic protein (GFAP). The electron microscopy was applied for ultrastructure study.
Results. Histopathological examination of the posterior funiculus of the white matter revealed minute hemorrhages and localized necrotic areas on day 1, which transformed to areas of cavitation and fibrinoid necrosis surrounded by a demarcating rim of numerous astrocytes by day 7. The mean percentage of area of GFAP expression increased significantly by day 7. Osmic acid staining revealed swollen nerve fibers after one day, while numerous fibers had been lost by day 7. An ultrastructure study revealed swollen redundant thinned myelin and myelin splitting, as well as degeneration of axoplasm on day 1. On day 7, layers of the myelin sheath were folded and wrinkled with partial or complete demyelination areas. The myelin lamellae were disorganized and loose. The G-ratio was significantly greater on day 1 than day 7 after CSCI.
Conclusions. In the rat model of CSCI details of the progressive spinal cord injury can be analyzed by morphological methods and may be helpful in the identification of the onset and type of clinical intervention
Ordered growth of vanadyl phthalocyanine (VOPc) on an iron phthalocyanine (FePc) monolayer
The growth and characterisation of a non-planar phthalocyanine (Vanadyl Phthalocyanine, VOPc) on a complete monolayer (ML) of a planar phthalocyanine (Iron (II) Phthalocyanine, FePc) on an Au (111) surface, has been investigated using ultra-high vacuum (UHV) scanning tunnelling microscopy (STM) and low energy electron diffraction (LEED). The surface mesh of the initial FePc monolayer has been determined and shown to correspond to an incommensurate overlayer, not commensurate as previously reported. Ordered islands of VOPc, with (1x1) epitaxy, grow on the FePc layer at submonolayer coverages. The individual VOPc molecules occupy sites directly atop the underlying FePc molecules, indicating that significant intermolecular bonding must occur. It is proposed that this interaction implies that the V=O points down into the surface, allowing a Fe-O bond to form. The detailed appearance of the STM images of the VOPc molecules is consistent with previous studies in other VOPc growth studies in which this molecular orientation has been proposed
Modeling of Tsunami Generation and Propagation by a Spreading Seismic Faulting in two Orthogonal Directions in Linearized Shallow-Water Wave Theory
The process of tsunami evolution during its generation in search for possible amplification mechanisms resulting from spreading of the sea floor uplift in the x-and y-direction is investigated under the effect of rupture velocities, uplift length and width and rise times. This study shows that focusing and amplification of tsunami amplitudes can occur in an arbitrary direction, determined by the velocities of spreading. Tsunami waveforms within the frame of the linearized shallow water theory for constant water depth are analyzed analytically by transform methods (Laplace in time and Fourier in space) for the spreading source model. We analyzed the normalized peak amplitude as a function of the propagated uplift length, width and the average depth of the ocean along the generation path. The amplification of tsunami amplitudes builds up progressively as time increases during the generation process due to wave focusing while the maximum wave amplitude decreases with time during the propagation process due to the geometric spreading and also due to dispersion. The normalized peak amplitudes were smaller when the slip-fault spreads in two orthogonal directions than the numerical values for one dimensional solution because of the interaction of the velocities. The maximum amplitude amplification is proportion to the propagation length and the width of the source model and inversely proportional with the water depth
Structural templating in a nonplanar phthalocyanine using single crystal copper iodide
Solution-grown copper iodide crystals are used as substrates for the templated growth of the nonplanar vanadyl phthalocyanine using organic molecular beam deposition. Structural characterization reveals a single molecular orientation produced by the (111) Miller plane of the copper iodide crystals. These fundamental measurements show the importance of morphology and structure in templating interactions for organic electronics applications
Ogbu and the debate on educational achievement: an exploration of the links between education, migration, identity and belonging
This paper looks at some of the issues raised by Ogbuâs work in relation to the education of different minority ethnic groups. Ogbu poses questions such as the value attached to education,
its links to the future and its measurable outcomes in terms of âsuccessâ as experienced by black participants. The desire for better life chances leads families to consider migration to a new country or resettlement within the same country, thus making migration both a local and a global phenomenon. As an example, attention is drawn to the situation facing South Asian
children and their families in the UK. In terms of ethnicity and belonging, the wider question that is significant for many countries in the West after âNine-Elevenâ is the education of Muslim children. A consideration of this current situation throws Ogbuâs identification of âautonomous minorityâ into question. It is argued that a greater understanding of diverse needs has to be
accompanied by a concerted effort to confront racism and intolerance in schools and in society, thus enabling all communities to make a useful contribution and to avoid the âriskâ of failure and disenchantment
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