Numerical Modeling and Evaluation of PEM Used for Fuel Cell Vehicles

The present study sought to analyze a novel type of polymer membrane fuel cell to be used in vehicles. The performance of the fuel cell was evaluated by modeling the types of production–consumption heat in the anode and cathode (including half-reaction heat, activation heat, and absorption/desorption heat) and waterflood conditions. The meshing of flow channels was carried out by square cells and the governing equations were numerically discretized in the steady mode using the finite difference method followed by solving in MATLAB software. Based on the simulation results, the anodic absorption/desorption heat, anodic half-reaction heat, and cathodic activation heat are positive while the cathodic absorption/desorption heat and cathodic half-reaction heat show negative values. All heat values exhibit a decremental trend over the flow channel. Considering the effect of relative humidity, the relative humidity of the cathode showed no significant change while the anode relative humidity decreased along the flow channel. The velocity at the membrane layer was considerably lower, due to the smaller permeability coefficient of this layer compared to the gas diffusion and reactants (cathode) layers.

The D5 Silo of Manganese of the Lampreana (Zamora): History, Construction Characteristics and Technology

Spain’s National Network of Silos and Granaries building a total de 665 silos and 285 granaries. 20 different typologies of silos were built, highlighting type D over all of them with a total of 389 units. This typology prolonged its construction for 34 years, appearing several subtypes (D1, D2, D3 D4 y D5). The Manganese of the Lampreana silo (Zamora) is a D5 type silo with 3,350 t of storage capacity, distributed in 24 storage tanks called cells, built in 1968. Architecturally speaking it is a simple and powerful silo. It has a rectangular shape, made up of three rows of square cells, the outer rows of cells rested directly on the ground storey floor and the center row is raised. Front tower between two cells, being embedded between them in a central position, achieving a compact and robust volume. The structure is made up of reinforced concrete pillars at the corners of the cells and the cell walls of reinforce bricks. Technologically speaking it has many similarities with its predecessors, types A and B. Here the elevator receives the grain directly from the reception hopper raising wheat and emptying it onto an upper horizontal belt conveyor, where dampers motorized valves, it is distributed across other tubes to one of the three cells in each bay. The grain is unloaded onto lower horizontal belt conveyors lying at different heights. From there it is carried to a raised cell for bulk offloading onto a lorry.

A Binary Integer Programming Method for Optimal Wind Turbines Allocation

The present study introduces a Binary Integer Programming (BIP) method to minimize the number of wind turbines needed to be installed in a wind farm. The locations of wind turbines are selected in a virtual grid which is constructed considering a minimum distance between the wind turbines to avoid the wake effect. Additional equality constraints are also included to the proposed formulation to prohibit or enforce the installation of wind turbines placement at specific locations of the wind farmland. Moreover, a microscopic wind turbine placement considering the local air density is studied. To verify the efficiency of this proposal, a square site was subdivided into 25 square cells providing a virtual grid with 36 candidate placement locations. Moreover, a virtual grid with 121 vertices related with a Greek island is also tested. All simulations conducted considering the area of geographical territory, the length of wind turbine blades, as well as the capacity of each turbine.

Adaptive Radial Basis Function Partition of Unity Interpolation: A Bivariate Algorithm for Unstructured Data

In this article we present a new adaptive algorithm for solving 2D interpolation problems of large scattered data sets through the radial basis function partition of unity method. Unlike other time-consuming schemes this adaptive method is able to efficiently deal with scattered data points with highly varying density in the domain. This target is obtained by decomposing the underlying domain in subdomains of variable size so as to guarantee a suitable number of points within each of them. The localization of such points is done by means of an efficient search procedure that depends on a partition of the domain in square cells. For each subdomain the adaptive process identifies a predefined neighborhood consisting of one or more levels of neighboring cells, which allows us to quickly find all the subdomain points. The algorithm is further devised for an optimal selection of the local shape parameters associated with radial basis function interpolants via leave-one-out cross validation and maximum likelihood estimation techniques. Numerical experiments show good performance of this adaptive algorithm on some test examples with different data distributions. The efficacy of our interpolation scheme is also pointed out by solving real world applications.

Application of block-discretization method for analysis of electrical conductivity of graphene-containing shungite.

The block-discretization method for calculation of electrical conductivity of graphene-contained shungite is proposed and realized in practice. It is established that in the basis of forming of shungite carbon conductivity is presented the structure and arrangement of graphene packets which may be investigated only by electron microscopy method. The card of space allocation of graphene packets on the flat section of shungite specimen is brought. It is found two varieties of graphene packets distribution – regular when packets forms the ribbons one after the other and irregular when the packets are oriented in arbitrary directions. As a result of this cards character it is proposed to distinguish two varieties of observed structure – power-contrast which is formed by regulated ribbons and weak-contrast which is formed by chaotic oriented graphene packets. On the basis of model of current-tubes the valuing of electrical resistance for both kinds of structure is made. As a maximum cases for conditions of current flow it is investigated two orientation of packets inside of tube – suitable when the layers of graphene are oriented along the axis of tube and unsuitable when the layers of graphene are oriented across the axis of tube. In this case it is taken into account that the resistance of graphene packet across the layer is more then the resistance of its layer along the plane on three orders and more. It is found that the main resistance of tube is formed not only by graphene layers but in the most influence of joint from neighbouring graphene packets. The method of making of contour card which consist of the construction of boundaries between two kinds of structure and tracing the contour lines which correspond to individual ribbons in these boundaries is proposed. From the consideration of cards of flat section of structure it is established that the arrangement of packets, its orientation and conditions of grouping in general have same character in different parts of whole card. It is established that the extracted from the whole structure sufficient small area has the same specific conductivity as the whole structure. For the analysis of whole structure the method of block-discretization is proposed. This method consist of the breaking the whole massif on parts which are sufficiently similar to each other and analysis of several parts with subsequent averaging. It is supposed that the parameters of this averaged part may be calculated using simple means. After these actions the received meanings of parameters are repeated so times as it is necessary and as a result it is found the parameters of whole structure. The detailed step-by-step algorithm of using block-discretization method for the founding the specific conductivity of whole structure using the contour card of flat section of specimen is proposed. As a procedure of discretization it is proposed the breaking of whole card on square parts which are named as “blocks”. After this breaking from the different localizations from whole card it is chooses several blocks which parameters are subjected to averaging. After these actions it is constructed the net which is the same as initial net on the whole card but in this case the cells of this net are filled by equal averaged blocks. The calculation of parameters of whole card which consist of equal blocks gives the parameters of initial task. The application of block-discretization method is considered on the example of real shungite specimen from the deposit Nigozero which structure contains the ribbons intermitted by unregulated packets. It is constructed the contour card of specimen part having dimensions 40 x 40 nm. On this card is applied the net with square cells having dimension 10 x 10 nm which breaks the whole card into 16 blocks. It is made the secondary block discretization of blocks so as on the each block applied the net having cells 1 x 1 nm. Using this net the areas of block which contain the ribbons and unregulated packets and also the length and quantity of ribbons in block are found. The results of these measuring are averaged above all blocks. On the basis of averaged values of block parameters the geometrical structure of averaged block is constructed. It is found that the block may be presented as the closely packed on the flat of structure which consist of the equal single current tubes. In this case equal single tube consist of two successive connected parts. The first of these parts correspond to suitable orientation of grapheme packets and the second correspond to unsuitable orientation of the same packets. Using the received by electron microscopy methods parameters of grapheme layers and packets and also the gaps between its the resistance of single tube and averaged block consisted of these tubes is calculated. In supposition that the shungite structure is uniform in three axis on the basis of single tube and averaged block parameters the specific conductivity of carbon part of shungite is calculated. It is found that the obtained value of specific conductivity in comparison of specific conductivity of real shungite containing 97% carbon is larger approximate in three-four times. It is proposed the optimization of model by consideration into account the gap between packets and volume distribution of tubes in isotropic structure. These additions allows to obtain the good agreement between received data and meanings of conductivity of real shungites. In briefly mentioned some possibilities of development this work, mentioned the universal character of block-discretization method and mentioned some possible tasks for its application.

Diversidad anatómica de cinco biotipos de la especie Theobroma cacao(cacao) en la región sur de Ecuador

Agrobiodiversity includes variability at the specific and genetic level, its dynamics and relationships between cultivated plants and their wild relatives. The Theo b ro m a c a c aoL. species has a high cultural and economic value inEcuador because it helps around 100,000 rural families. However, the structure of its wood and the variability of microscopic characteristics between its biotypes is unknown. For this reason, this study seeks to fill th is gap with an anatomical analysis of the wood in its three planes (transverse, tangentia l, a n d radial) according to IAWA regulations in five biotypes of T. cocoa (aromático, criollo, forastero, trinitario y CCN51) from the Piuntza and Guayzimi sectors of the province of Zamora Chinchipe. Itwas found that all biotypes presented simple perforation plates, alternating polygonal pits, diffuse axial parenchyma, multiseriate and uniseriate ra y s , ra y s with procumbent cells of 2-4 rows of vertical and / or marginal square cells,h ow e ve r, th e prismatic crystals, drusen, envelope cells, and perforated radial cells were variable. At a quantitative level, the highest radii were found mainly in the creole and fore ign b io ty pe s , while the CCN51 and trinitariobiotypes obtained higher values in vessels per square millimeter. With this, it was shown that all the individuals analyzed, despite being of the same species, had anatomical differences, which shows that the microscopic study of woo d is a very useful tool for the identification of biotypes within a species.Keywords:Wood anatomy, cacao, biotype, IAWA, agrobiodiversity

Evaluation of Different Designs of Isolated Cells to Raise Single Rice Seedlings for SRI Mechanized Transplanting

Numerous benefits of the system of rice intensification (SRI) have been documented since SRI was popularized 30 years ago. To date, more than 58 rice growing countries are practicing SRI, covering around 4 million ha of paddy fields and involving more than 10 million farmers. Many paddy farmers shy away from practicing SRI due to extreme labour endurance and number of labors required, especially during transplanting and frequent weeding. The manual transplanting technique to ensure proper root establishment of the seedlings, makes SRI less appealing to many paddy farmers. Furthermore, the transplanting shock is a problem arises from manual transplanting technique needs to be solved that resulted to damaged roots causing delays in crop establishment and reducing productivity. Mechanized transplanting of the young single seedlings into the paddy fields at a wider plantation area eliminates drudgery and enables better exposure to sunlight, water, air, and nutrients. This paper presents a solution to overcome the problem of transplanting shock and the back-breaking manual transplanting, which was achieved by containing the roots of each seedling in a grid of isolated cells. Several designs of the isolated cells to contain the root system were fabricated and tested. These include using aluminum square cells, polyvinyl chloride pipe circular cells, biodegradable grid cells, biodegradable conical capsules, and germinated seeds sowed in a grid without isolated cells. The typical grid cell size was 15 mm by 15 mm with a depth of each cell varied from 40 mm to 60 mm. The most promising design was one with single seedlings raised in bio-degradable capsules arranged close together to fit the conventional rice seedling tray of 300 mm by 600 mm and can accommodate 684 capsules per tray. Upon reaching 2-3 leaf stage, the seedlings with undisturbed roots are ready to be transplanted into the paddy fields using the currently available rice transplante rs.

Damage Size Estimation for Composite Laminates Based on an Anisotropic Wavefront Expression

A Multistage Elliptical Parametric (MEP) method is developed in this research for damage size evaluation in anisotropic composite laminates. The Lamb waves are actuated and sensed using piezoelectric (lead zirconate titanate, PZT) transducers arranged as a network of square cells. The dynamic response signals are processed using a continuous wavelet transformation (CWT) based on the Gabor wavelet for accurate time of flight (ToF) measurements. A numerical method is developed for the construction of non-elliptic path loci for each actuator-sensor pair. The damage is localized first using the least squares method, and then the damage edge points are located on each non-elliptic path loci as points which have the minimum distance from the damage location. The MEP method based on the damage edge points is implemented in multiple stages for damage size evaluation in a cross-ply laminate. Each stage is designed on the basis on excitation of specific prearranged transducers inside the square cell. The results indicate that the MEP method can quantitatively estimate the size of an elliptical damage in cross-ply laminates.

Faraday Waves in a Square Cell Network: The Effects of Varying the Cell Size

We have conducted experiments of the Faraday instability in a network of square cells filled with water for driving frequencies and amplitudes in the intervals 10≤F≤22 Hz and 0.1≤A≤3 mm, respectively. The experiments were aimed at studying the effects of varying the size of the cells on the surface wave patterns. Images of the surface wave patterns were recorded with a high-speed camera. The time series of photographs composing each video was Fourier analyzed, and information about the waveforms was obtained by using a Pearson correlation analysis. For small square cells of side length l=2.5 cm, adjacent cells collaborate synchronously to form regular patterns of liquid bumps over the entire grid, while ordered matrices of oscillons are formed at higher frequencies. As the size of the cells is increased to l=5 cm, collective cell behaviour at lower frequencies is no longer observed. As the frequency is increased, a transition from three triangularly arranged oscillons within each cell to three, or even four, irregularly arranged oscillons is observed. The wave patterns, the waveforms and the energy content necessary to excite Faraday waves are seen to depend on the cell size.

Measurement of local shear deformation in fabric drape using three-dimensional scanning

We propose a measuring method of shear deformation in drape using three-dimensional (3D) scanning. We measured the local shear angles in fabric drape based on the Fabric Research Laboratories (FRL) drape test for woven fabrics using the proposed method. We investigate the effects of the relative positions of the node to the center grainlines that cross at the fabric center, and the bending and shear properties of fabric on the shear angles. To measure the local shear deformation, we obtained 3D drape shapes of four different fabrics with three to six nodes. We covered the obtained drape shapes using a fabric model composed of square cells that allowed shear deformation. By calculating the shear angles of the cells, we obtained the local shear deformation. We found that the FRL drape can be characterized by three areas, except for the flat areas of the support disks: (a) areas along the center grainlines with zero or small shear angles within 3°, which could result from single curvature bending; (b) areas in the bias directions with relatively large shear angles over 3°, which could result from double curvature bending; and (c) polygon edges connected by tangents of the support disk with relatively larger shear angles than their surroundings, which could result from both bending and shear deformation, such as folding and wrinkles. By investigating the relationships between areas with large shear angles and the bending rigidity/shear stiffness, we clarified that the bending rigidity indirectly affects the local shear deformation of drape.