Mixed convection in a baffled grooved channel

Indian Academy of Sciences (India)

MS received 16 May 2014; revised 19 October 2014; accepted 06 November 2014. Abstract. In the present numerical work, flow structure and heat transfer charac- teristics are investigated in a baffled grooved channel, differentially heated from the sides. The baffle is placed vertically downward from the top wall of grooved ...

The baffle influence on sound radiation characteristics of a plate

Directory of Open Access Journals (Sweden)

Bao Liu

2017-01-01

Full Text Available The acoustic radiation characteristics of the baffle plates and unbaffle plates are calculated and compared by single-layer potential and double-layer potential. Based on the boundary integral equation, the sound pressure integral equation of the baffle and the baffle are deduced respectively. According to the boundary compatibility condition, the sound pressure and the vibration velocity of the plates are obtained. Further, the dynamic equation of the structure is substituted into the vibration equation in the form of the baffle plate and the baffle plate. The sound pressure difference and the displacement of a plate surface are in the form of the vibration mode superposition and the acoustic radiation impedance of the double integral form is obtained, which determines vibration mode coefficient and sound radiation parameters. The effect of the baffle on the acoustic radiation characteristics of the thin plate is analyzed by comparing the acoustic radiation parameters with the simple and simple rectangular plate in water.

Numerical investigation of the performances of axial separation helical baffle heat exchangers

International Nuclear Information System (INIS)

Tang, Hongling; Chen, Yaping; Wu, Jiafeng; Yang, Shifan

2016-01-01

Highlights: • Seriation incline angles of axial separation reduce helical baffle manufacture cost. • Adjacent helical baffles are separated by sleeve tubes to form a greater pitch helix. • Flow and thermal performances of normal and axial separation schemes were simulated. • Deviation of h.t.c. or pressure drop of 21(15)° and 21° schemes is −1.21% or 4.96%. • Seriation step of baffle incline angles can be extended to 8° by axial separation. - Abstract: Axial separation is a novel baffle connection configuration of circumferential overlap helical baffle heat exchangers which makes baffle incline angle seriation possible. The adjacent baffle plates are separated by sleeve tubes to form a greater pitched helix for enhancing heat transfer under required pressure drop with the least number of molds for reducing baffle manufacture cost. Numerical simulations of flow and heat transfer performances were conducted and the calculation results were verified by the experimental ones. Performance investigation was conducted on eight normal trisection helical baffle schemes with baffle incline angles from 15° to 23° and five axial separation schemes of equivalent 17–22° angles using 15° baffles. In the calculation scope the average deviations of heat transfer coefficients and pressure drops of the normal helical schemes are respectively about −1.97% and −8.11% per 1° deviation of incline angle. The axial separation schemes using 15° baffles with equivalent 21° and 22° incline angles have deviation values of heat transfer coefficient 1.21% and 1.33% lower and pressure drop 4.96% and 5.55% higher respectively than those of the normal 21° and 22° incline angle schemes. By adopting axial separation approach the seriation step of baffle incline angles can be extended to 8°.

Vacuum outgassing from diffuse-absorptive baffle materials

International Nuclear Information System (INIS)

Egert, C.M.; Basford, J.A.

1990-01-01

Quantitative measurements of outgassing for Martin black and a variety of metallic, diffuse absorptive baffle materials under development for stray light management are reported in this paper. Outgassing measurements were made during pumpdown from atmosphere at room temperature. Mass scans indicate water was the major outgassing species for all materials tested. Calibrated measurements of water vapor outgassing as a function of time were also made for each baffle material. Most baffle materials exhibited total water vapor outgassed during pumpdown of between 1 x 10 -5 and 4 x 10 -5 moles/cm 2 . Plasma sprayed beryllium, currently under development exhibited approximately an order of magnitude lower total water vapor outgassed during pumpdown

Energy Loss, Velocity Distribution, and Temperature Distribution for a Baffled Cylinder Model

Science.gov (United States)

Brevoort, Maurice J

1937-01-01

A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that cooling can be improved by 20 percent by using a correctly designed baffle. Such a gain is as effective as a 65 percent increase in pressure drop across the standard baffle, which had a 1/4 inch clearance between baffle and fin tips.

Exergetic performance evaluation of a single pass baffled solar air heater

International Nuclear Information System (INIS)

Sabzpooshani, M.; Mohammadi, K.; Khorasanizadeh, H.

2014-01-01

In this study, the exergetic performance of a baffled type solar air heater has been evaluated theoretically. A detailed parametric study was done to investigate the effect of variation of fin and baffle parameters, number of glass covers, bottom insulation thickness and inlet air temperature at different mass flow rates on the exergy efficiency. The results indicated that attaching fins and baffles at low mass flow rates can lead to noticeable enhancement of the exergy efficiency. The results revealed that the trend of variation of the energy and exergy efficiencies are not the same and the exergy efficiency is the chief criterion for performance evaluation. Increasing the baffles width, reducing the distance between baffles and increasing the number of fins are effective at low mass flow rates, but at high mass flow rates the inverse trend is observable, such that exergy efficiency reduces sharply. The results showed that exergy efficiency increases with increasing the solar radiation intensity. By adding the second glass cover the exergy efficiency enhances at low mass flow rates. Increasing the insulation thickness over an optimum value doesn't improve the exergy efficiency. Increasing the inlet air temperature increases the exergy efficiency especially at high mass flow rates. - Highlights: • We study the exergetic performance of an upward type baffled solar air heater. • The effect of several design parameters on the performance is investigated. • Exergetic performance is very sensitive to the variation of baffles parameters. • Adding fins and baffles and increasing their parameters are efficient at low m . . • At high m . increment of baffles parameters causes decline of the exergy efficiency

Vibro-impact responses of a tube with tube--baffle interaction

International Nuclear Information System (INIS)

Shin, Y.S.; Sass, D.E.; Jendrzejczyk, J.A.

1978-01-01

The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments

Relay telescope including baffle, and high power laser amplifier utilizing the same

Science.gov (United States)

Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

2006-09-19

A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

Design and manufacturing of WEST Baffle

International Nuclear Information System (INIS)

Batal, Tristan; Firdaouss, Mehdi; Richou, Marianne; Ferlay, Fabien; Larroque, Sébastien; Gargiulo, Laurent; Dupas, Timothée; Verger, Jean-Marc; Doceul, Louis; Samaille, Franck; Bucalossi, Jérôme; Salami, Michael

2015-01-01

Highlights: • Disruption's torque in the PFC was simulated thanks to ANSYS. • The ANSYS thermal results comply with WEST project requirements. • The cycling analysis complies with WEST project requirements. • 316L components comply with A level RCC-MRx criteria. - Abstract: The Tore Supra tokamak is being transformed in an X-point divertor fusion device in the frame of the WEST project, launched in support to the Iter tungsten divertor strategy. The WEST Baffle aims to evacuate particles by creating a toroidal pumping throat. It also protects the lower divertor cooling pipes and the passive stabilization plate from heat fluxes. The Baffle is made of actively cooled plasma facing components (PFCs), with underneath a passive stabilization plate and a support beam. The Baffle design is presented in a first part. In a second time the different ANSYS simulations are described: electromagnetic, thermal and mechanical results are presented. The design choices are justified for the different results obtained thanks to the simulation. In a final part, some aspects of the PFC manufacturing are presented.

Ageing management of baffle former bolts in Belgian nuclear power plants

International Nuclear Information System (INIS)

Somville, F.; Gerard, R.; Bosch, R.W.; Bertolis, D.; Vissers, S.

2015-01-01

The Pressurized Water Reactors internals support the reactor core, distribute the coolant flow through the core, and guide and protect the rod control cluster assemblies and in-core instrumentation. The baffle-to-former bolts are used in Pressurized Water Reactors to attach the baffle plates to the former plates in the reactor vessel lower internals. The resulting structure forms a boundary for the flow of coolant and provides lateral support to the fuel assemblies. Some edge bolts are also present, assembling together the baffle plates. After an operating time of the order of 120.000 hours, some bolts exhibit cracking at the junction of the head and the shank of the bolt. Examinations of failed bolts have made it possible to identify the cause of cracking as irradiation assisted stress corrosion cracking (IASCC). Up to now, baffle bolt cracking has been detected in units older than 15 years, where the baffle bolts are not cooled (no holes in the former to allow a water flow on the bolt shank). In Belgium, the concerned units are Tihange 1 and Doel 1-2. The paper summarizes the experience with baffle bolts cracking in Belgian units and the strategy implemented to mitigate this problem, consisting of structural integrity analyses, baffle bolts inspections and replacement, and research programs in the field of IASCC, including examinations of highly irradiated replaced bolts. (authors)

Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands

Science.gov (United States)

Lihu Cui; Ying Ouyang; Weizhi Yang; Zhujian Huang; Qiaoling Xu; Guangwei Yu

2015-01-01

Three new baffle flow constructed wetlands (CWs), namely the baffle horizontal flow CW (Z1), baffle vertical flow CW (Z2) and baffle hybrid flow CW (Z3), along with one traditional horizontal subsurface flow CW (Z4) were designed to test the removal efficiency of nitrogen (N) and phosphorus (P) from the septic tank effluent under varying hydraulic retention times (HRTs...

Vibro-impact responses of a tube with tube--baffle interaction. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Shin, Y S; Sass, D E; Jendrzejczyk, J A

1978-01-01

The relatively small, inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the vibrational characteristics and the response of the tube. Numerical studies were made to predict the vibro-impact response of a tube with tube-baffle interaction. The finite element method has been employed with a non-linear elastic contact spring-dashpot to model the effect of the relative approach between the tube and the baffle plate. The coupled equations of motion are directly integrated with a proportional system damping represented by a linear combination of mass and stiffness. Lumped mass approach with explicit time integration scheme was found to be a suitable choice for tube-baffle impacting analysis. Fourier analyses indicate that the higher mode contributions to the tube response are significant for strong tube-baffle impacting. The contact damping forces are negligible compared with the contact spring forces. The numerical analysis results are in reasonably good agreement with those of the experiments.

The baffle-barrel-bolting analysis program: evolution and technical accomplishments

International Nuclear Information System (INIS)

Schwirian, R.E.; Forsyth, D.R.; Snyder, M.D.; Bhandari, D.R.; Barsic, J.A.; Rabenstein, W.D.

2001-01-01

In Westinghouse pressurized water reactors (PWR) the reactor core is surrounded by baffle plates, which provide lateral restraint for the fuel assemblies at the core boundary. Baffle plates are attached to horizontal supports called former plates by baffle-former bolts. The formers are attached to the core barrel which also provides vertical support for the core. The B3 analysis program addresses the possibility of reduced baffle-former bolting in Westinghouse U.S. domestic plant designs with respect to the relevant design criteria. Since safety is the overriding motivation for the program, faulted events have received the most in-depth attention. This focus has been reinforced by the fact that the loads produced by the loss-of-coolant-accident (LOCA) have usually been the most limiting of all those considered. Consequently, much of the presentation below deals with the development of analysis techniques and acceptance criteria to demonstrate that LOCA-induced loads on the bolts and the fuel assemblies will be acceptable with significantly reduced baffle-former bolting. A discussion of the other faulted, normal, and upset analyses performed as part of the program will also be presented. (author)

Thermal Hydraulic Performance in a Solar Air Heater Channel with Multi V-Type Perforated Baffles

Directory of Open Access Journals (Sweden)

Anil Kumar

2016-07-01

Full Text Available This article presents heat transfer and fluid flow characteristics in a solar air heater (SAH channel with multi V-type perforated baffles. The flow passage has an aspect ratio of 10. The relative baffle height, relative pitch, relative baffle hole position, flow attack angle, and baffle open area ratio are 0.6, 8.0, 0.42, 60°, and 12%, respectively. The Reynolds numbers considered in the study was in the range of 3000–10,000. The re-normalization group (RNG k-ε turbulence model has been used for numerical analysis, and the optimum relative baffle width has been investigated considering relative baffle widths of 1.0–7.0.The numerical results are in good agreement with the experimental data for the range considered in the study. Multi V-type perforated baffles are shown to have better thermal performance as compared to other baffle shapes in a rectangular passage. The overall thermal hydraulic performance shows the maximum value at the relative baffle width of 5.0.

Energy efficiency improvement and fuel savings in water heaters using baffles

International Nuclear Information System (INIS)

Moeini Sedeh, Mahmoud; Khodadadi, J.M.

2013-01-01

Highlights: ► Thermal efficiency improved by simple/novel design of baffles inside water reservoir. ► Noticeable steady-state natural gas savings of about 5%. ► Extensive 3-D numerical investigations followed by experimental verifications. ► Baffle designs prototyped in identical water heaters for ANSI/US DOE test protocols. ► Numerical/experimental results verified thermal efficiency improvement and fuel savings. -- Abstract: Thermal efficiency improvement of a water heater was investigated numerically and experimentally in response to presence of a baffle, particularly designed for modifying the flow field within the water reservoir and enhancing heat transfer extracted into the water tank. A residential natural gas-fired water heater was selected for modifying its water tank through introducing a baffle for lowering natural gas consumption by 5% as a target. Based on the geometric features of the selected water heater, three-dimensional models of the water heater subsections were developed. Upon detailed studies of flow and heat transfer in each subsection, various sub-models were integrated to a complete model of the water heater. Thermal performance of the selected water heater was investigated numerically using computational fluid dynamics analysis. Prior to baffle design process and in order to verify the developed model of the water heater, time-dependent numerically-predicted temperatures were compared to the experimentally-measured temperatures under the same conditions at six (6) different locations inside the water tank and good agreement was observed. Upon verifying the numerical model, the fluid flow and heat transfer patterns were characterized for the selected water heater. The overall design of the baffle and its location and orientation were finalized based on the numerical results and a set of parametric studies. Finally, two baffle designs were proposed, with the second design being an optimized version of the first design. The

Stress evaluation of baffle former bolt for IASCC failure prediction

International Nuclear Information System (INIS)

Matsubara, T.; Tsutsui, T.; Kamei, Y.; Kitsu, M.

2011-01-01

Baffle structure in PWRs Reactor is quite important assembly for the core safety, and Baffle Former Bolts (BFBs) are fastener members for maintaining Baffle structure. It has been reported worldwide that some of BFBs were cracked due to IASCC (Irradiation Assisted Stress Corrosion Cracking) because BFBs are located at core region under severe environments, high neutron flux, high temperature and high stress. According to the material studies of IASCC on austenitic stainless steel, a crack initiation of IASCC is strongly related with the stress and the neutron fluence. For this reason, it is very important for IASCC failure prediction to simulate the stress of BFBs. However, the stress of BFBs are considered to be influenced by several factors and to be changed complexly as operational time increases, by irradiation creep of Bolt itself, swelling of Baffle structure, and so on. Therefore, it is difficult to estimate the stress histories of BFBs (Bolt stress as a function of operational time) precisely. Then, the author has developed the calculation method of the stress histories of BFBs considering irradiation effects (swelling and irradiation creep). In this method, the stress histories of BFBs are calculated by combining two kinds of FE models, Global model (modeled whole Baffle structure which consists of Baffle plates, Former plates and Core Barrel) and Local model (modeled around BFB finely). The whole Baffle structure deformation changes as a function of heat, swelling and irradiated creep are calculated by Global model, and the stress histories of BFBs are calculated by Local model using the outputs (deformations on driving nodes) of Global model. In the FE analysis of Local model, the stress of BFBs are calculated considering irradiation effects and elastic-plastic characteristics depending on neutron fluence, so this method enables to calculate precisely the stress of extreme small area of BFBs surface. This paper shows the outline of the calculation method

Study of Baffle Boundary and System Parameters on Liquid-Solid Coupling Vibration of Rectangular Liquid-Storage Structure

Directory of Open Access Journals (Sweden)

Wei Jing

2016-01-01

Full Text Available In order to study the vibration problem of liquid-solid coupling of rectangular liquid-storage structure with horizontal elastic baffle, ignoring the influence of surface gravity wave, two different velocity potential functions corresponding to the liquid above and below the elastic baffle are assumed; based on the theory of mathematical equation and energy method, the formulas of basic frequency of liquid-solid coupling vibration system are derived, the baffle joined to the tank wall with 3 kinds of boundary conditions, namely, four edges simply supported, two opposite edges clamped and two opposite edges simply supported, and four edges clamped; the influence rules of baffle length-width ratio, the ratio of baffle height to liquid level, baffle elastic modulus, baffle density, baffle thickness, and liquid density on the coupling vibration performance are studied. The results show that the frequency of the clamped boundary is minimum; the influences of baffle length-width ratio and relative height on the basic frequency are much greater than that of the other system parameters; the relation between baffle length-width ratio and the frequency is exponential, while baffle relative height has a parabola relation with the frequency; the larger the baffle length-width ratio, the closer the baffle to the liquid level; the coupling frequency will be reduced more obviously.

Coupled thermo-elastic and optical performance analyses of a reflective baffle for the BepiColombo laser altimeter (BELA) receiver

Science.gov (United States)

Heesel, E.; Weigel, T.; Lochmatter, P.; Rugi Grond, E.

2017-11-01

For the BepiColombo mission, the extreme thermal environment around Mercury requires good heat shields for the instruments. The BepiColombo Laser altimeter (BELA) Receiver will be equipped with a specular reflective baffle in order to limit the solar power impact. The design uses a Stavroudis geometry with alternating elliptical and hyperbolic vanes to reflect radiation at angles >38° back into space. The thermal loads on the baffle lead to deformations, and the resulting changes in the optical performance can be modeled by ray-tracing. Conventional interfaces, such as Zernike surface fitting, fail to provide a proper import of the mechanical distortions into optical models. We have studied alternative models such as free form surface representations and compared them to a simple modeling approach with straight segments. The performance merit is presented in terms of the power rejection ratio and the absence of specular stray-light.

Low Frequency Sloshing Analysis of Cylindrical Containers with Flat and Conical Baffles

Directory of Open Access Journals (Sweden)

Gnitko V.

2017-12-01

Full Text Available This paper presents an analysis of low-frequency liquid vibrations in rigid partially filled containers with baffles. The liquid is supposed to be an ideal and incompressible one and its flow is irrotational. A compound shell of revolution is considered as the container model. For evaluating the velocity potential the system of singular boundary integral equations has been obtained. The single-domain and multi-domain reduced boundary element methods have been used for its numerical solution. The numerical simulation is performed to validate the proposed method and to estimate the sloshing frequencies and modes of fluid-filled cylindrical shells with baffles in the forms of circular plates and truncated cones. Both axisymmetric and non-axisymmetric modes of liquid vibrations in baffled and un-baffled tanks have been considered. The proposed method makes it possible to determine a suitable place with a proper height for installing baffles in tanks by using the numerical experiment.

Numerical Simulation of Sloshing Phenomena in Cubic Tank with Multiple Baffles

Directory of Open Access Journals (Sweden)

Mi-An Xue

2012-01-01

Full Text Available A two-phase fluid flow model solving Navier-Stokes equations was employed in this paper to investigate liquid sloshing phenomena in cubic tank with horizontal baffle, perforated vertical baffle, and their combinatorial configurations under the harmonic motion excitation. Laboratory experiment of liquid sloshing in cubic tank with perforated vertical baffle was carried out to validate the present numerical model. Fairly good agreements were obtained from the comparisons between the present numerical results and the present experimental data, available numerical data. Liquid sloshing in cubic tank with multiple baffles was investigated numerically in detail under different external excitation frequencies. Power spectrum of the time series of free surface elevation was presented with the aid of fast Fourier transform technique. The dynamic impact pressures acting on the normal and parallel sidewalls were discussed in detail.

Optimized baffle and aperture placement in neutral beamlines

International Nuclear Information System (INIS)

Stone, R.; Duffy, T.; Vetrovec, J.

1983-01-01

Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. We have found that the beam losses can be reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field can be supplied by current coils without the iron poles. In addition, placement of the baffles and apertures can affect the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. In our study we varied the placement of the baffles, which determine the amount of pumping in each chamber, and the apertures, which determine the beam loss. Our results indicate that a baffle/aperture configuration can be set for either minimum cold gas into the plasma region or minimum beam losses, but not both

Influence of slosh baffles on thermodynamic performance in liquid hydrogen tank.

Science.gov (United States)

Liu, Zhan; Li, Cui

2018-03-15

A calibrated CFD model is built to investigate the influence of slosh baffles on the pressurization performance in liquid hydrogen (LH 2 ) tank. The calibrated CFD model is proven to have great predictive ability by compared against the flight experimental results. The pressure increase, thermal stratification and wall heat transfer coefficient of LH 2 tank have been detailedly studied. The results indicate that slosh baffles have a great influence on tank pressure increase, fluid temperature distribution and wall heat transfer. Owning to the existence of baffles, the stratification thickness increases gradually with the distance from tank axis to tank wall. While for the tank without baffles, the stratification thickness decreases firstly and then increases with the increase of the distance from the axis. The "M" type stratified thickness distribution presents in tank without baffles. One modified heat transfer coefficient correlation has been proposed with the change of fluid temperature considered by multiplying a temperature correction factor. It has been proven that the average relative prediction errors of heat transfer coefficient reduced from 19.08% to 4.98% for the wet tank wall of the tank, from 8.93% to 4.27% for the dry tank wall, respectively, calculated by the modified correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

Energy Loss, Velocity Distribution, and Temperature Distribution for a Baffled Cylinder Model, Special Report

Science.gov (United States)

Brevoort, Maurice J.

1937-01-01

In the design of a cowling a certain pressure drop across the cylinders of a radial air-cooled engine is made available. Baffles are designed to make use of this available pressure drop for cooling. The problem of cooling an air-cooled engine cylinder has been treated, for the most part, from considerations of a large heat-transfer coefficient. The knowledge of the precise cylinder characteristics that give a maximum heat-transfer coefficient should be the first consideration. The next problem is to distribute this ability to cool so that the cylinder cools uniformly. This report takes up the problem of the design of a baffle for a model cylinder. A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that the cooling can be improved 20% by using a correctly designed baffle. Such a gain is as effective in cooling the cylinder with the improved baffle as a 65% increase in pressure drop across the standard baffle and fin tips.

A Probabilistic Approach to Baffle Bolt IASCC Predictions

International Nuclear Information System (INIS)

Griesbach, Timothy J.; Licina, George J.; Riccardella, Peter C.; Rashid, Joe R.; Nickell, Robert E.

2012-01-01

A methodology for evaluating the probability of baffle-former bolt cracking was developed for applicability to PWRs. The methodology is based upon IASCC test results for the stainless steels most commonly used for baffle-former bolts (e.g., Type 304 SA, Type 347 SA, and Type 316 CW) and predictions of the representative stress patterns in those bolts that were developed as inputs to the model. The predictive methodology for IASCC is based on a single parameter that was developed to incorporate the combined effects of dose and stress ratio (applied stress divided by yield strength, where the yield strength includes irradiation hardening) plus a Weibull statistical distribution that is defined in terms of that parameter. Baffle-former bolt cracking has been observed in a number of PWRs, and these incidents have raised concerns about the likelihood of future cracking or failures. In this damage model, IASCC 'failure' is defined when the component becomes fully susceptible to stress corrosion cracking; that is, after a certain level of irradiation and sustained stress. The length of time required for the material to become fully susceptible was determined from IASCC test data. IASCC crack initiation, which is defined to be equivalent to failure as noted above, is defined by an IASCC susceptibility curve from the test data that relates applied stress and cumulative neutron dose. The dose duration under constant stress is interpreted as the incubation time needed to make the material susceptible to stress corrosion cracking, after which crack initiation and propagation to full rupture under constant stress will occur within a relatively short time (hundreds of hours). The IASCC failure model uses the calculated stress in a material such as the baffle-former bolt and calculates a damage index as the ratio of the current applied stress to the allowable stress as a function of irradiation dose. IASCC initiation data for various irradiated bolting materials was obtained from

The examination of the effects of the flow baffle on the thermal hydraulic performance of IHX shell side

International Nuclear Information System (INIS)

Kim, W. K.; Sim, Y. S.; Kim, S. O.; Baek, B. J.

2002-01-01

The effects of the flow baffle on the thermal hydraulic performance of IHX shell side has been examined using ASTEEPL, 2DHX code for the variation of baffle distance, baffle cut and baffle flow hole design data. When KALIMER design data were selected as a base for the study, a shell baffle structures does not influence on a total heat transfer rate and it is better to reduce baffle distance rather than baffle flow hole size from the view of pressure loss in the IHX. Radial thermal imbalance between tubes was reduced to 6 .deg. C when the number of baffle is beyond 13. And thermal imbalance decreased also when flow hole size decreases. If flow hole clogs perfectly, thermal imbalance can be reduced up to 2 .deg. C

Numerical investigation on a novel shell-and-tube heat exchanger with plate baffles and experimental validation

International Nuclear Information System (INIS)

Yang, Jie; Liu, Wei

2015-01-01

Highlights: • A novel shell-and-tube heat exchanger with plate baffles is proposed. • Heat transfer and pressure drop of computational calculations are studied. • Experimental method is carried out to verify the modeling approach. • Path lines, temperature field and pressure field are analyzed. - Abstract: A novel shell-and-tube heat exchanger with new plate baffles is proposed. It is numerically investigated in comparison with a shell-and-tube heat exchanger with rod baffles. Commercial softwares FLUENT 6.3 and GAMBIT 2.3 are adopted for modeling and computational calculations. The modeling approach is verified with experimental approach. The shell-side results of heat transfer, flow performance, and comprehensive performance are analyzed. The Nusselt number for the plate baffles heat exchanger is around 128–139% of that for the rod baffles heat exchanger. The pressure drop for the novel one is about 139–147% of that for the rod baffles heat exchanger. Overall, the novel plate baffles heat exchanger illustrates evidently higher comprehensive performance (115–122%) than the rod baffles one. The temperature field, pressure field, and path lines are analyzed to demonstrate the advantage of the novel shell-and-tube heat exchanger

CFD simulation of alleviation of fluid back mixing by baffles in bubble column

Energy Technology Data Exchange (ETDEWEB)

Xia, Y.K.; Peng, F.F.; Wolfe, E. [Sedgman LLC, Pittsburgh, PA (United States)

2006-07-15

The global back mixing of liquid in an open flotation column is harmful to mineral separations. The inclusion of baffles and packing in open columns can dampen the effects of global back mixing. A mathematical model based on the principle of fluid dynamics is helpful in designing baffled or packed columns. This paper presents a two-dimensional Euler-Lagrangian model to simulate the multiphase flow for some cases of baffled and packed columns. Fluid motion is calculated by directly solving the Navier-Stokes equations by a SIMPLE approach. Bubbles are moved in a Lagrangian frame through the interaction forces imposed by the gas-fluid coupling. The simulated results successfully reveal that the liquid back-mixing effect in the open bubble columns can be alleviated by baffles or packings.

Wave impact on a deck or baffle

Science.gov (United States)

Md Noar, Nor Aida Zuraimi; Greenhow, Martin

2015-02-01

Some coastal or ocean structures have deck-like baffles or horizontal platforms that can be exposed to wave action in heavy seas. A similar situation may occur in partially-filled tanks with horizontal baffles that become engulfed by sloshing waves. This can result in dangerous wave impact loads (slamming) causing a rapid rise of pressures which may lead to local damaging by crack initiation and/or propagation. We consider the wave impact against the whole of underside of horizontal deck (or baffle) projecting from a seawall (or vertical tank wall), previously studied by Wood and Peregrine (1996) using a different method based on conformal mappings. The approach used is to simplify the highly time-dependent and very nonlinear problem by considering the time integral of the pressure over the duration of the impact pressure-impulse, P (x, y). Our method expresses this in terms of eigenfunctions that satisfy the boundary conditions apart from that on the impact region and the matching of the two regions (under the platform and under the free surface); this results in a matrix equation to be solved numerically. As in Wood and Peregrine, we found that the pressure impulse on the deck increases when the length of deck increases, there is a strong pressure gradient beneath the deck near the seaward edge and the maximum pressure impulse occurs at the landward end of the impact zone.

Modelling of baffled stirred tanks

Energy Technology Data Exchange (ETDEWEB)

Ahlstedt, H.; Lahtinen, M. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

1996-12-31

The three-dimensional flow field of a baffled stirred tank has been calculated using four different turbulence models. The tank is driven by a Rushton-type impeller. The boundary condition for the impeller region has been given as a source term or by calculating the impeller using the sliding mesh technique. Calculated values have been compared with measured data. (author)

Modelling of baffled stirred tanks

Energy Technology Data Exchange (ETDEWEB)

Ahlstedt, H; Lahtinen, M [Tampere Univ. of Technology (Finland). Energy and Process Engineering

1997-12-31

The three-dimensional flow field of a baffled stirred tank has been calculated using four different turbulence models. The tank is driven by a Rushton-type impeller. The boundary condition for the impeller region has been given as a source term or by calculating the impeller using the sliding mesh technique. Calculated values have been compared with measured data. (author)

A study of the various baffles used in the Marcoule chimneys and the search for a new model (1961)

International Nuclear Information System (INIS)

Chassany, J.; Salaun-Penquer, G.

1961-01-01

The baffle placed at the top of a chimney determines the shape of the smoke pall for low exit-velocities. The G. 1 type baffle was studied taking into account the characteristics of its collar: totally hollow - partially hollow - solid; on a ribbed chimney or on a plain chimney. The Pu type baffle was also tested. The search for a new type of baffle was limited to variants of the blade - type baffle: - a porous envelope device; - a cone - shaped device and - a deflector of the cupel type. Only the blade-type baffle was rejected, efficient solutions are proposed using the other types or their combinations. (authors) [fr

The effects of baffles and gas superficial velocity on a bubble fluidized bed reactor's applications

International Nuclear Information System (INIS)

Ghorbanpour, A.; Ghannadi Maragheh, M.; Mallah, M. H.

2008-01-01

Baffles are used for decreasing bubbles diameter in order to increase the conversion rate along the bubbling fluidized bed reactors. The appearance of this phenomenon is due to bursting of the bubbles during the pass of bubbles from baffles. In this work, a computerized modeling and simulation have been performed in order to obtain a fundamental knowledge of the influence of the baffles on the bubble diameter and the specific mass transfer area. The height of the bed is 5 meters and its diameter is 0.3 meter. Baffles are located at 1 and 2 meters from the bottom of the bed. A two phase model together with a comprehensive fluid dynamical description of bubbling fluidized is presented. The effects of baffles and gas superficial velocity on the operating behavior of fluidized bed reactors are considered. The results are compared to the previously reported documents, and the experiments which have been carried out. MATLAB software is used in this simulation

Optical and mechanical design and characterization of the new baffle for the 2.4-m Thai National Telescope

Science.gov (United States)

Buisset, Christophe; Prasit, Apirat; Lépine, Thierry; Poshyajinda, Saran

2015-09-01

The first astronomical images obtained at the 2.4 m Thai National Telescope (TNT) during observations in bright moon conditions were contaminated by high levels of light scattered by the telescope structure. We identified that the origins of this scattered light were the M3 folding mirror baffle and the tube placed inside the fork between the M3 and the M4 mirrors. We thus decided to design and install a new baffle. In a first step, we calculated the optical and mechanical inputs needed to define the baffle optical design. These inputs were: the maximum length of the baffle, the maximum dimensions of the vanes and the incident beam diameter between M3 and M4 mirrors. In a second step, we defined the number, the position and the diameter of the vanes to remove the critical objects from the detector's FOV by using a targeted method. Then, we verified that the critical objects were moved away from the detector's view. In a third step, we designed and manufactured the baffle. The mechanical design is made of 21 sections (1 section for each vane) and comprises an innovative mechanism for the adjustment of the baffle position. The baffle installation and adjustment is performed in less than 20 minutes by 2 operators. In a fourth step, we installed and characterized the baffle by using a pinhole camera. We quantified the performance improvement and we identified the baffle areas at the origin of the residual stray light signal. Finally, we performed targeted on-sky observations to test the baffle in real conditions.

Estimation of material degradation of VVER-1000 baffle

Science.gov (United States)

Harutyunyan, Davit; Koš'ál, Michal; Vandlík, Stanislav; Hojná, Anna; Schulc, Martin; Flibor, Stanislav

2017-09-01

The planned lifetime of the first commercial VVER-1000 units were designed for 30 to 35 years. Most of the early VVER plants are now reaching and/or passing the 35-year mark. Service life extension for another 10 to 30 years is now under investigation. Life extension requires the evaluation of pressure vessel internals degradation under long-term irradiation. One of the possible limiting factors for the service life of VVERs is a void swelling of the Russian type titanium stabilized stainless 08Ch18N10T steel used to construct the baffle surrounding the core. This article aims to show first steps towards deeper analysis of the baffle degradation process and to demonstrate the possibilities of precise calculation and measurements on the VVER-1000 mock-up in LR-0 reactor.

SAFL Baffle retrofit for suspended sediment removal in storm sewer sumps.

Science.gov (United States)

Howard, Adam; Mohseni, Omid; Gulliver, John; Stefan, Heinz

2011-11-15

Standard sumps (manholes) provide a location for pipe junctions and maintenance access in stormwater drainage systems. Standard sumps can also remove sand and silt particles from stormwater, but have a high propensity for washout of the collected sediment. With appropriate maintenance these sumps may qualify as a stormwater best management practice (BMP) device for the removal of suspended sediment from stormwater runoff. To decrease the maintenance frequency and prevent standard sumps from becoming a source of suspended sediment under high flow conditions, a porous baffle, named the SAFL Baffle, has been designed and tested as a retrofit to the sump. Multiple configurations with varying percent open area and different angles of attack were evaluated in scale models. An optimum configuration was then constructed at the prototype scale and evaluated for both removal efficiency and washout. Results obtained with the retrofit indicate that with the right baffle dimensions and porosity, sediment washout from the sump at high flow rates can be almost eliminated, and removal efficiency can be significantly increased at low flow rates. Removal efficiency and washout functions have been developed for standard sumps retrofitted with the SAFL Baffle. The results of this research provide a new, versatile stormwater treatment device and implemented new washout and removal efficiency testing procedures that will improve research and development of stormwater treatment devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands.

Science.gov (United States)

Cui, Lihua; Ouyang, Ying; Yang, Weizhi; Huang, Zhujian; Xu, Qiaoling; Yu, Guangwei

2015-04-15

Three new baffle flow constructed wetlands (CWs), namely the baffle horizontal flow CW (Z1), baffle vertical flow CW (Z2) and baffle hybrid flow CW (Z3), along with one traditional horizontal subsurface flow CW (Z4) were designed to test the removal efficiency of nitrogen (N) and phosphorus (P) from the septic tank effluent under varying hydraulic retention times (HRTs). Results showed that the optimal HRT was two days for maximal removal of N and P from the septic tank effluent among the four CWs. At this HRT, the Z1, Z2, Z3 and Z4 CWs removed, respectively, 49.93, 58.50, 46.01 and 44.44% of TN as well as 87.82, 93.23, 95.97 and 91.30% of TP. Our study further revealed that the Z3 CW was the best design for overall removal of N and P from the septic tank effluent due to its hybrid flow directions with better oxygen supply inside the CW system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Numerical Analysis of Edge Over Coating and Baffle Effect on Hot-Dip Galvanizing

Science.gov (United States)

Bao, Chengren; Kang, Yonglin; Li, Yan

2017-06-01

In hot-dip galvanizing process, air jet wiping control is so crucial to determine the coating thickness and uniformity of the zinc layer on the steel strip. A numerical simulation of gas-jet wiping in hot-dip galvanizing was conducted to minimize the occurrence of edge over coating (EOC). The causes of EOC were identified by contrasting and analyzing the airflow fields on the strip edge with and without a baffle. The factors influencing the airflow field on the strip edge during the change in the gap between the baffle and the strip edge were also analyzed. The effect of the distance between the air knife and the strip was evaluated. Technological parameters with on-site guidance role were obtained by combining them with the actual production to elucidate the role of the baffle in restraining the occurrence of EOC. The uniform distribution of pressure and coating thickness on the strip is achieved when the distance of the baffle from the strip edge is about 0.3 times of the jetting distance.

Effects of Movable-Baffle on Heat Transfer and Entropy Generation in a Cavity Saturated by CNT Suspensions: Three-Dimensional Modeling

Directory of Open Access Journals (Sweden)

Abdullah A.A.A. Al-Rashed

2017-04-01

Full Text Available Convective heat transfer and entropy generation in a 3D closed cavity, equipped with adiabatic-driven baffle and filled with CNT (carbon nanotube-water nanofluid, are numerically investigated for a range of Rayleigh numbers from 103 to 105. This research is conducted for three configurations; fixed baffle (V = 0, rotating baffle clockwise (V+ and rotating baffle counterclockwise (V− and a range of CNT concentrations from 0 to 15%. Governing equations are formulated using potential vector vorticity formulation in its three-dimensional form, then solved by the finite volume method. The effects of motion direction of the inserted driven baffle and CNT concentration on heat transfer and entropy generation are studied. It was observed that for low Rayleigh numbers, the motion of the driven baffle enhances heat transfer regardless of its direction and the CNT concentration effect is negligible. However, with an increasing Rayleigh number, adding driven baffle increases the heat transfer only when it moves in the direction of the decreasing temperature gradient; elsewhere, convective heat transfer cannot be enhanced due to flow blockage at the corners of the baffle.

Effect of Baffles on the Sloshing in Road Tankers Carrying LPG: A Comparative Numerical Study

Directory of Open Access Journals (Sweden)

J. L. Bautista-Jacobo

2015-01-01

Full Text Available This work presents a comparative numerical study of the effect of using baffles, and its design, on the behavior of sloshing in a partially filled road tanker carrying LPG. Navier-Stokes equations and standard k-ε turbulence model are used to simulate fluid movement; the Volume of Fluid (VOF method is used to track the liquid-gas interface. Velocity distributions, sloshing stabilization times, and contours of turbulent kinetic energy, which are of high importance in choosing the best design of baffles, are shown. The results show sloshing stabilization times of 22 and 21 s for road tankers with cross-shaped (Type I and X-shaped (Type II baffles, respectively, finding lower values of turbulent kinetic energy for Type II design, being, therefore, the best design of baffles for damping of sloshing and vehicle control among studied ones.

Nuclear reactor core flow baffling

International Nuclear Information System (INIS)

Berringer, R.T.

1979-01-01

A flow baffling arrangement is disclosed for the core of a nuclear reactor. A plurality of core formers are aligned with the grids of the core fuel assemblies such that the high pressure drop areas in the core are at the same elevations as the high pressure drop areas about the core periphery. The arrangement minimizes core bypass flow, maintains cooling of the structure surrounding the core, and allows the utilization of alternative beneficial components such as neutron reflectors positioned near the core

Validity of Miles Equation in Predicting Propellant Slosh Damping in Baffled Tanks at Variable Slosh Amplitude

Science.gov (United States)

Yang, H. Q.; West, Jeff

2018-01-01

Determination of slosh damping is a very challenging task as there is no analytical solution. The damping physics involves the vorticity dissipation which requires the full solution of the nonlinear Navier-Stokes equations. As a result, previous investigations were mainly carried out by extensive experiments. A systematical study is needed to understand the damping physics of baffled tanks, to identify the difference between the empirical Miles equation and experimental measurements, and to develop new semi-empirical relations to better represent the real damping physics. The approach of this study is to use Computational Fluid Dynamics (CFD) technology to shed light on the damping mechanisms of a baffled tank. First, a 1-D Navier-Stokes equation representing different length scales and time scales in the baffle damping physics is developed and analyzed. Loci-STREAM-VOF, a well validated CFD solver developed at NASA MSFC, is applied to study the vorticity field around a baffle and around the fluid-gas interface to highlight the dissipation mechanisms at different slosh amplitudes. Previous measurement data is then used to validate the CFD damping results. The study found several critical parameters controlling fluid damping from a baffle: local slosh amplitude to baffle thickness (A/t), surface liquid depth to tank radius (d/R), local slosh amplitude to baffle width (A/W); and non-dimensional slosh frequency. The simulation highlights three significant damping regimes where different mechanisms dominate. The study proves that the previously found discrepancies between Miles equation and experimental measurement are not due to the measurement scatter, but rather due to different damping mechanisms at various slosh amplitudes. The limitations on the use of Miles equation are discussed based on the flow regime.

Optimal design of sandwich ribbed flat baffle plates of a circular cylindrical tank

International Nuclear Information System (INIS)

Malinowski, Marek; Magnucki, Krzysztof

2005-01-01

The subject of this paper is a sandwich ribbed flat baffle plate of a circular cylindrical tank. The paper deals with a problem of optimal thickness of this construction with a soft core. The construction is distinguished by a local axisymmetric pre-springing. The mathematical description is based on the theory of shells with analysis of disturbance of the stress membrane state. The sandwich ribbed flat baffle plate divides the tank into two chambers. One of them is loaded by uniform pressure, while the other is empty and unloaded. Dimensions of ribs, faces and the entire baffle plate have been determined with a view to minimize the mass under strength constraints. The effect of optimal thickness of this sandwich plate has been examined by means of the finite element method

Baffles Promote Wider, Thinner Silicon Ribbons

Science.gov (United States)

Seidensticker, Raymond G.; Mchugh, James P.; Hundal, Rolv; Sprecace, Richard P.

1989-01-01

Set of baffles just below exit duct of silicon-ribbon-growing furnace reduces thermal stresses in ribbons so wider ribbons grown. Productivity of furnace increased. Diverts plume of hot gas from ribbon and allows cooler gas from top of furnace to flow around. Also shields ribbon from thermal radiation from hot growth assembly. Ribbon cooled to lower temperature before reaching cooler exit duct, avoiding abrupt drop in temperature as entering duct.

Reactor Vessel and Reactor Vessel Internals Segmentation at Zion Nuclear Power Station - 13230

Energy Technology Data Exchange (ETDEWEB)

Cooke, Conrad; Spann, Holger [Siempelkamp Nuclear Services: 5229 Sunset Blvd., (Suite M), West Columbia, SC, 29169 (United States)

2013-07-01

Zion Nuclear Power Station (ZNPS) is a dual-unit Pressurized Water Reactor (PWR) nuclear power plant located on the Lake Michigan shoreline, in the city of Zion, Illinois approximately 64 km (40 miles) north of Chicago, Illinois and 67 km (42 miles) south of Milwaukee, Wisconsin. Each PWR is of the Westinghouse design and had a generation capacity of 1040 MW. Exelon Corporation operated both reactors with the first unit starting production of power in 1973 and the second unit coming on line in 1974. The operation of both reactors ceased in 1996/1997. In 2010 the Nuclear Regulatory Commission approved the transfer of Exelon Corporation's license to ZionSolutions, the Long Term Stewardship subsidiary of EnergySolutions responsible for the decommissioning of ZNPS. In October 2010, ZionSolutions awarded Siempelkamp Nuclear Services, Inc. (SNS) the contract to plan, segment, remove, and package both reactor vessels and their respective internals. This presentation discusses the tools employed by SNS to remove and segment the Reactor Vessel Internals (RVI) and Reactor Vessels (RV) and conveys the recent progress. SNS's mechanical segmentation tooling includes the C-HORCE (Circumferential Hydraulically Operated Cutting Equipment), BMT (Bolt Milling Tool), FaST (Former Attachment Severing Tool) and the VRS (Volume Reduction Station). Thermal segmentation of the reactor vessels will be accomplished using an Oxygen- Propane cutting system. The tools for internals segmentation were designed by SNS using their experience from other successful reactor and large component decommissioning and demolition (D and D) projects in the US. All of the designs allow for the mechanical segmentation of the internals remotely in the water-filled reactor cavities. The C-HORCE is designed to saw seven circumferential cuts through the Core Barrel and Thermal Shield walls with individual thicknesses up to 100 mm (4 inches). The BMT is designed to remove the bolts that fasten the Baffle

Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe U – Tube Terhadap Aliran Fluida Dan Perpindahan Panas

Directory of Open Access Journals (Sweden)

Reza Hidayatullah

2014-09-01

Full Text Available Alat penukar kalor sangat berpengaruh dalam industri terhadap keberhasilan keseluruhan rangkaian proses, karena kegagalan operasi alat ini baik akibat kegagalan mekanikal maupun opersional dapat menyebabkan berhentinya operasi unit. Penelitian terhadap desain heat exchanger masih terus dilakukan untuk mencari kinerja dari heat exchanger yang paling optimal, baik pada bagian baffle cut dan baffles inclination maupun susunan dari tube dengan menggunakan heat exchanger ukuran kecil sebagai model. Berdasarkan pada permasalahan di atas, maka dilakukan penelitian terhadap kinerja heat exchanger tipe U-tube dengan memvariasikan baffle inclination. Penelitian ini dilakukan secara numerik dengan variasi baffle inclination sebesar 0o, 10o, 20o dan variasi laju aliran massa sebesar 0,5 kg/s, 1kg/s, dan 2 kg/s. Tube yang digunakan adalah tipe U-tube yang disusun secara persegi. Model viskous yang digunakan adalah turbulensi model yaitu k-ε standar, dimana fluida yang digunakan adalah air pada boundary condition. Hasil analisa numerik menunjukkan adanya pengaruh baffle inclination pada alat penukar kalor tipe U – tube terhadap aliran fluida dan perpindahan panas. Peningkatan laju aliran massa dapat meningkatkan pressure drop secara cepat, alat penukar kalor shell and tube tipe U – tube dengan baffle inclination 20o memiliki unjuk kerja yang terbaik dibandingkan dengan baffle inclination 0o dan 10o.

Determination of in-service change in the geometry of WWER-1000 core baffle: Calculations and measurements

International Nuclear Information System (INIS)

Margolin, B.Z.; Varovin, A.Y.; Minkin, A.J.; Sorokin, A.A.; Piminov, V.A.; Evdokimenko, V.V.; Fedosovsky, M.E.; Sherstobitov, A.E.; Ovchinnikov, A.G.; Pikulik, S.S.; Erak, D.Y.; Bobkov, A.V.; Timofeev, A.M.; Timokhin, V.I.; Yakushev, S.V.; Vasiliev, V.G.

2015-01-01

The paper gives the basic constitutive equations describing radiation swelling and creep depending on neutron dose, irradiation temperature and triaxial stress state, and justifies these equations experimentally. The WWER-1000 core baffle change in geometry was calculated by different models describing the effect of stresses on radiation swelling. The calculated results are compared with the measured ones for the operating WWER-1000 core baffle at the Balakovo NPP, Unit 1. A method of individual prediction of core baffle geometry change on the basis of the measurement results has been proposed. (authors)

Core baffle for nuclear reactors

International Nuclear Information System (INIS)

Machado, O.J.; Berringer, R.T.

1977-01-01

The invention concerns the design of the core of a LWR with a large number of fuel assemblies formed by fuel rods and kept in position by spacer grids. According to the invention, at the level of the spacer grids match plates are mounted with openings so the flow of coolant directed upwards will not be obstructed and a parallel bypass will be obtained in the space between the core barrel and the baffle plates. In case of an accident, this configuration reduces or avoids damage from overpressure reactions. (HP) [de

Investigation of Damping Physics and CFD Tool Validation for Simulation of Baffled Tanks at Variable Slosh Amplitude

Science.gov (United States)

Yang, H. Q.; West, Jeff

2016-01-01

Determination of slosh damping is a very challenging task as there is no analytical solution. The damping physics involves the vorticity dissipation which requires the full solution of the nonlinear Navier-Stokes equations. As a result, previous investigations were mainly carried out by extensive experiments. A systematical study is needed to understand the damping physics of baffled tanks, to identify the difference between the empirical Miles equation and experimental measurements, and to develop new semi-empirical relations to better represent the real damping physics. The approach of this study is to use Computational Fluid Dynamics (CFD) technology to shed light on the damping mechanisms of a baffled tank. First, a 1-D Navier-Stokes equation representing different length scales and time scales in the baffle damping physics is developed and analyzed. Loci-STREAM-VOF, a well validated CFD solver developed at NASA MSFC, is applied to study the vorticity field around a baffle and around the fluid-gas interface to highlight the dissipation mechanisms at different slosh amplitudes. Previous measurement data is then used to validate the CFD damping results. The study found several critical parameters controlling fluid damping from a baffle: local slosh amplitude to baffle thickness (A/t), surface liquid depth to tank radius (d/R), local slosh amplitude to baffle width (A/W); and non-dimensional slosh frequency. The simulation highlights three significant damping regimes where different mechanisms dominate. The study proves that the previously found discrepancies between Miles equation and experimental measurement are not due to the measurement scatter, but rather due to different damping mechanisms at various slosh amplitudes. The limitations on the use of Miles equation are discussed based on the flow regime.

A three-dimensional numerical investigation of trapezoid baffles effect on non-isothermal reactant transport and cell net power in a PEMFC

International Nuclear Information System (INIS)

Perng, Shiang-Wuu; Wu, Horng-Wen

2015-01-01

Highlights: • We study how angle and height of trapezoid baffle affect PEMFC net power. • The jet-type, trapping, and blockage effects augment non-isothermal transport in flow channel. • Greater angles and heights of trapezoid baffles provide more reactant to the catalyst layer. • Baffles of 1.5 mm and 90° fully block flow channel to show bad heat transfer and large pressure drop. • Maximum enhancement of cell net power is 90% with baffles of 60° angle and 1.125 mm height. - Abstract: The present study performed a three-dimensional numerical simulation to observe how trapezoid baffles affect non-isothermal reactant transports and cell net power in the proton exchange membrane fuel cell (PEMFC) by the SIMPLE-C method. The geometric parameters of trapezoid baffles installed in the gas channel employed in this study include the angle and height with the same gas diffusion and catalyst layers to realize the cell net power considering the effect of liquid water formation on the fluid flow field. The cell net power is adopted to evaluate the real enhancement of cell performance due to the additional pumping power induced by the pressure loss through the PEMFC. The results illustrated that compared with traditional gas channel without baffles, the novel gas channel with trapezoid baffles, whose angle is 60° and height is 1.125 mm, enhances the cell net power best by approximately 90% among all trapezoid baffle designs

Performance Study of Solar Air Heater Having Absorber Plate with Half-Perforated Baffles

OpenAIRE

Maheshwari, B. K.; Karwa, Rajendra; Gharai, S. K.

2011-01-01

The paper presents a detailed mathematical model for performance prediction of a smooth duct solar air heater validated against the experimental results. Experimental study on a solar air heater having absorber plate with half-perforated baffles on the air flow side shows thermal efficiency enhancement of 28%–45% over that of the smooth duct solar air heater, which is attributed to the heat transfer enhancement (of the order of 180%–235%) due to the perforated baffles attached to the absorber...

CORRIDOR-TYPE BAFFLED MIXING BASIN WITH CROSS POROUS BARRIERS

Directory of Open Access Journals (Sweden)

S. M. Epoyan

2018-02-01

Full Text Available Purpose. The paper hightlights the increase in operational efficiency of corridor-type baffled mixing basin by installing of cross porous barriers made of gravel (or other materials and epoxy resin, grade ED-20 (ED-16 with the hardener polyethylenepolyamine (PEPA, approved by Ukrainian Ministry of Health in systems of utility and drinking water supply. Methodology. The first stage of the experiments was performed on the model of the proposed mixer in scale 1:4 in order to determine the local resistance of the porous barrier, which is made of gravel with a size of 10-15 mm (average diameter 12.5 mm and thickness of 50 mm. The local resistance of the barrier was measured using piezometers installed before and after the porous barrier. The velocity of water motion in the corridor of the mixer was determined depending on the water consumption, incoming on the mixer accordingly to the water meter and by the volumetric method. Findings. In accordance with researches when the water flows at a velocity of 0.1 m/s in the corridor of the mixer, the head losses in the porous barrier is 17 cm (0.17 m, and at a velocity of 0.2 m/s–0.68 m. The resistance coefficient (ξ, which is equal to 333.2 for the investigated barrier, was determined experimentally. It allows determining the head losses in the porous barrier at other velocities of water motion. When the velocity of water motion in the corridors of the mixer is from 0.7 up to 0.5 m/s, head losses increase almost fourfold. The conducted researches allowed to develop a calculation methodology for corridor-type baffled mixing basin with porous polymer-concrete barriers. Originality. Authors developed and investigated the corridor-type baffled mixing basin with porous polymer-concrete barriers. These barriers allow increasing and regulating the intensity and time of reagents mixing with the initial water exactly in the barriers, improving the distribution of the flow through the section of the mixer

Stability of inner baffle-shell of pool type LMFBR - experimental and theoretical studies

International Nuclear Information System (INIS)

Lebey, J.; Combescure, A.

1987-01-01

I pool type LMFBR, the primary coolant circuit, inside the main vessel, comprises a hot plenum separated from a cold plenum by an inner baffle. For Superphenix 1 reactor, it was judged advisable to built a double-shell baffle, each shell withstanding only one type of loading (primary loading for one shell, secondary loading for the other). Due to the size and intricacy of the structure, this design involves unnegligible supplementary costs and manufacturing difficulties. Thus, an alternative solution has been studied for future plants projects. It consists of a single shell baffle having a shape especially studied to sustain the two types of applied loadings (thermal plus primary loadings). Such a shape was calculated by NOVATOME, and it was decided to check the ability of methods of analysis to predict the ruin of this structure under primary loading. For this purpose, a mock-up has been tested, and the experimental results compared with the calculated ones. (orig./GL)

A Computational Fluid Dynamics Study of Swirling Flow Reduction by Using Anti-Vortex Baffle

Science.gov (United States)

Yang, H. Q.; Peugeot, John W.; West, Jeff S.

2017-01-01

An anti-vortex baffle is a liquid propellant management device placed adjacent to an outlet of the propellant tank. Its purpose is to substantially reduce or eliminate the formation of free surface dip and vortex, as well as prevent vapor ingestion into the outlet, as the liquid drains out through the flight. To design an effective anti-vortex baffle, Computational Fluid Dynamic (CFD) simulations were undertaken for the NASA Ares I vehicle LOX tank subjected to the simulated flight loads with and without the anti-vortex baffle. The Six Degree-Of-Freedom (6-DOF) dynamics experienced by the Crew Launch Vehicle (CLV) during ascent were modeled by modifying the momentum equations in a CFD code to accommodate the extra body forces from the maneuvering in a non-inertial frame. The present analysis found that due to large moments, the CLV maneuvering has a significant impact on the vortical flow generation inside the tank. Roll maneuvering and side loading due to pitch and yaw are shown to induce swirling flow. The vortical flow due to roll is symmetrical with respect to the tank centerline, while those induced by pitch and yaw maneuverings showed two vortices side by side. The study found that without the anti-vortex baffle, the swirling flow caused surface dip during the late stage of drainage and hence early vapor ingestion. The flow can also be non-uniform in the drainage pipe as the secondary swirling flow velocity component can be as high as 10% of the draining velocity. An analysis of the vortex dynamics shows that the swirling flow in the drainage pipe during the Upper Stage burn is mainly the result of residual vortices inside the tank due to the conservation of angular momentum. The study demonstrated that the swirling flow in the drainage pipe can be effectively suppressed by employing the anti-vortex baffle.

A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

DEFF Research Database (Denmark)

Dich, Mikael; Rengarajan, S.R.

1997-01-01

An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

The anaerobic baffled reactor (ABR): An appropriate technology for ...

African Journals Online (AJOL)

This project has studied the appropriateness of the ABR for on-site primary sanitation in low-income communities. The baffled design of the ABR ensures high solids retention resulting in high treatment rates, while the overall sludge production is characteristically low. Effluent COD values measured from a 3 000 l pilot ABR ...

Treatment of domestic wastewater using conventional and baffled septic tanks.

Science.gov (United States)

Nasr, Fayza Aly; Mikhaeil, Basem

2013-01-01

The main theme of the study was a comparative study of domestic wastewater treatment using conventional and baffled septic tanks. The septic tanks were fed continuously with domestic wastewater at three different hydraulic retention times (HRTs). The HRTs chosen were 24, 48 and 72 h with corresponding organic loads of 0.321, 0.436 and 0.885 kg chemical oxygen demand (COD) per m3 per day, respectively. The performance of the septic tanks at the three HRTs gave satisfactory results. For the conventional septic tank, COD removal was 53.4%, 56% and 65.3%, at an HRT of 24, 48 and 72 h, respectively, with residual COD of 412, 380 and 334mg/l, respectively. At HRTs of 72, 48 and 24 h, the following percentages removals were realized for: biochemical oxygen demand (BOD), 68.4%, 57, 53.5%; total suspended solid (TSS), 65.3%, 58.3, 55%; phosphorus, 29.3%, 26.9, 25.6%; total Kjeldahl nitrogen 26.8%, 20.8, 17.7%, respectively. On the contrary, ammonia concentrations increased by 7.1%, 5.2 and 4.2% under the same conditions. Consequently, the results showed that the removal of fecal coliform at all HRTs was less than one log. The two baffled septic tanks exhibited superior results at HRTs of 72, 48 and 24 h. Comparing the treated domestic wastewater quality produced by the two types of septic tanks in terms of physico-chemical and biological characteristics, better results were obtained using the two baffles type.

Analytical and Experimental Study of Recycling Baffled Double-Pass Solar Air Heaters with Attached Fins

Directory of Open Access Journals (Sweden)

Chun Sheng Lin

2013-03-01

Full Text Available The study of the heat transfer of solar air heaters with a new design using an absorbing plate with fins and baffles, which facilitate the recycling of flowing air, is reported. The mathematical formulation and analytical analysis for such a recyclic baffled double-pass solar air heater were developed theoretically. The performance of the device was studied experimentally as well. The theoretical predicted and experimental results were compared with another design, i.e., a downward-type single-pass solar air heater without recycle and double-pass operations reported in our previous work. Significant improvement in heat-transfer efficiency is achieved with the baffle and fin design due to the recycling heating and the extended heat transfer area. The effects of mass flow rate and recycle ratio on the heat-transfer efficiency enhancement as well as on the power consumption increment are also discussed.

Treatment of a textile dye in the anaerobic baffled reactor | Bell ...

African Journals Online (AJOL)

scale anaerobic baffled reactor (ABR). The results of the physical decolorisation tests suggested significant decolorisation due to adsorption to the biomass; however, it is possible that the dye chromophores were reduced due to the low redox ...

Flow Control by Slot Position and Noise Baffle in a Self-Recirculation Casing Treatment on an Axial Fan-Rotor

Directory of Open Access Journals (Sweden)

Xiangjun Li

2017-01-01

Full Text Available To address the situations where the casing treatment needs to be used to stabilize axial compressors through strong recirculation, this paper initiated a CFD study to investigate how the flow could be suitably controlled in the casing treatment to minimize the efficiency penalty and increase the flow range. A counter-swirl self-recirculation casing treatment was first designed on a low speed axial fan rotor as a baseline case. Then three different slot positions and the influence of including the noise baffle were numerically studied. Based on the understanding of their coeffects, the shorter noise baffle was considered and it was found that the highest efficiency was achieved in the case of the upstream slot when the length of baffle was suitably adjusted to balance the incoming flow and recirculation. The largest flow range was achieved by locating the slot at the most downstream position and using a 50% length baffle since it suitably controlled the recirculating flow and relieved the separation at the low-span region. An optimization study showed that the optimum length of the baffle for efficiency was always larger than for the flow range. Both of the two optimum values reduce as the slot moves downstream.

On the dynamic spatial response of a heat exchanger tube with intermittent baffle contacts

International Nuclear Information System (INIS)

Rogers, R.J.; Pick, R.J.

1976-01-01

Flow-induced vibration in heat exchanger tubes can result in fretting wear at the baffle supports and subsequent tube failure. As one step in correlating the random flow excitation to the rate of fretting wear, this paper presents a dynamic finite element technique for predicting the motions and baffle contact forces of a single heat exchanger tube. Using a modal superposition approach, the modal equations of motion are generated and numerically integrated. The predicted results are compared with experimental data for both planar and spatial vibration of harmonically excited cantilevered beams with a clearance support at the free end. (Auth.)

Dynamic thermal baffle on lower head of FBR sodium-sodium intermediate heat exchanger

International Nuclear Information System (INIS)

Charbonnel, A.; Foussat, C.

1981-01-01

The cover head of the heat exchanger is bathed on the one side by the primary sodium of the 'cold' header of the vessel and on the other side by the secondary sodium which feeds the heat exchange tube bank through the lower tubesheet. In the case of transient or permanent operating conditions at partial ratings, there are large temperature differences between the inner sodium (inlet temperature conditions of secondary sodium) and the outer sodium (mean temperature conditions in the primary sodium outlet port), hence the necessity of designing a thermal baffle which protects the head and its connection to the tubesheet. A 'static' thermal baffle consisting of a thick steel plate enclosing static sodium around the head proves inadequate during transient operating conditions. This is why a 'dynamic' thermal baffle is used whose design is based on the fact that the primary sodium in the lower part of the outlet port is always at a temperature close to that of the secondary sodium in the inlet header and the head. The primary sodium is taken from the bottom of the outlet port by a ring deflector and circulates in an annulus created by a double housing and the head. It flows out through openings in the lower part of the housing. (orig./GL)

The effect of anaerobic baffled reactor effluent on nitrogen and ...

African Journals Online (AJOL)

Leaching of nitrogen and phosphorus from soil columns during application of anaerobic baffled reactor effluent was evaluated. The soils used were from Inanda (Ia), Cartref (Cf), and Sepane (Se) forms, and a silica sand (SS). Each was packed into duplicate columns (103 mm internal diameter; 200 mm length), four each for ...

Low cost anaerobic system for Indonesia: single baffled septic tank.

Science.gov (United States)

Wibisono, G; Mathew, K; Ho, Goen

2003-01-01

The insertion of a single baffle into a laboratory septic tank to mix incoming feed with sludge has been shown to improve anaerobic degradation of the feed. This is particularly true of soluble organic matter such as glucose. Oil or cellulose fed separately does not undergo degradation. It is expected however that a balanced feed such as sewage will be better degraded.

Modelos

Directory of Open Access Journals (Sweden)

Luis Argudín

2011-01-01

Full Text Available Este texto es una reflexión en torno a la categoría de modelos, que piensa con modelos, a partir de los modelos y para los modelos; también se piensa, se interpreta, se revisa, el significado del modelo. Y esto no sólo por lo que estos exigen su lugar desde la tradición artística, sino por lo que significan para la estética, y aún para la filosofía y la ciencia, pues de lo que se trata es de un ir y venir del pensamiento entre la materialidad y el ejercicio de pensar el oficio.

Optimizing the longitudinal and transverse electroosmotic pumping in a rectangular channel with horizontal baffle plates

Science.gov (United States)

Lai, Anison K. R.; Chang, Chien-Cheng; Wang, Chang-Yi

2018-04-01

This paper presents a continued study to our previous work on electroosmotic (EO) flow in a channel with vertical baffle plates by further investigating EO flow through an array of baffle plates arranged in parallel to the channel walls. The flow may be driven either in the direction along or in the direction transverse to the plates, thus distinguishing the longitudinal EO pumping (LEOP) and the transverse EO pumping (TEOP). In both types of EO pumping, it is more interesting to examine the cases when the baffle plates develop a higher zeta potential (denoted by α) than that on the channel walls (β). This semi-analytical study enables us to compare between LEOP and TEOP in the pumping efficiency under similar conditions. The TEOP case is more difficult to solve due to the higher order governing partial differential equations caused by the induced non-uniform pressure gradient distribution. In particular, we examine how the EO pumping rates deviate from those predicted by the Helmholtz-Smoluchowski velocity and illustrate the general trend of optimizing the EO pumping rates with respect to the physical and geometric parameters involved.

Thermal interaction of core melt debris with the TMI-2 baffle, core-former, and lower head structures

International Nuclear Information System (INIS)

Cronenberg, A.W.; Tolman, E.L.

1987-09-01

Recent inspection of the TMI-2 core-former baffle walls (vertical), former plates (horizontal), and lower plenum has been conducted to assess potential damage to these structures. Video observations show evidence of localized melt failure of the baffle walls, whereas fiberoptics data indicate the presence of resolidified debris on the former plates. Lower plenum inspection also confirms the presence of 20 tons or more of core debris in the lower plenum. These data indicate massive core melt relocation and the potential for melt attack on vessel structural components. This report presents analyses aimed at developing an understanding of melt relocation behavior and damage progression to TMI-2 vessel components. Thermal analysis indicates melt-through of the baffle plates, but maintenance of structural integrity of the former plates and lower head. Differences in the damage of these structures is attributed largely to differences in contact time with melt debris and pressure of water. 29 refs., 17 figs., 9 tabs

Passage and behaviour of cultured Lake Sturgeon in a prototype side-baffle fish ladder: I. Ladder hydraulics and fish ascent

Science.gov (United States)

Kynard, B.; Pugh, D.; Parker, T.

2011-01-01

Research and development of a fish ladder for sturgeons requires understanding ladder hydraulics and sturgeon behaviour in the ladder to insure the ladder is safe and provides effective passage. After years of research and development, we designed and constructed a full-scale prototype side-baffle ladder inside a spiral flume (38.3m long??1m wide??1m high) on a 6% (1:16.5) slope with a 1.92-m rise in elevation (bottom to top) to test use by sturgeons. Twenty-eight triangular side baffles, each extending part way across the flume, alternated from inside wall to outside wall down the ladder creating two major flow habitats: a continuous, sinusoidal flow down the ladder through the vertical openings of side-baffles and an eddy below each side baffle. Ascent and behaviour was observed on 22 cultured Lake Sturgeon=LS (Acipenser fulvescens) repeatedly tested in groups as juveniles (as small as 105.1cm TL, mean) or as adults (mean TL, 118cm) during four periods (fall 2002 and 2003; spring 2003 and 2007). Percent of juveniles entering the ladder that ascended to the top was greater in spring (72.7%) than in fall (40.9-45.5%) and 90.9% of 11 adults, which ascended as juveniles, ascended to the top. Six LS (27.3%) never swam to the top and seven (31.8%) swam to the top in all tests, indicating great variability among individuals for ascent drive. Some LS swam directly to the top in <1min, but most rested in an eddy during ascent. Juveniles swimming through outside wall baffle slots (mean velocity, 1.2ms-1) swam at 1.8-2.2body lengthss-1 and 3.2-3.3tail beatss-1, either at or approaching prolonged swimming speed. The side-baffle ladder was stream-like and provided key factors for a sturgeon ladder: a continuous flow and no full cross-channel walls, abundant eddies for resting, an acceptable water depth, and a water velocity fish could ascend swimming 2bls-1. A side-baffle ladder passes LS and other moderate-swimming fishes. ?? 2011 Blackwell Verlag, Berlin.

Computational Investigation on Fully Developed Periodic Laminar Flow Structure in Baffled Circular Tube with Various BR

Directory of Open Access Journals (Sweden)

Withada Jedsadaratanachai

2014-01-01

Full Text Available This paper presents a 3D numerical analysis of fully developed periodic laminar flow in a circular tube fitted with 45° inclined baffles with inline arrangement. The computations are based on a finite volume method, and the SIMPLE algorithm has been implemented. The characteristics of fluid flow are presented for Reynolds number, Re = 100–1000, based on the hydraulic diameter (D of the tube. The angled baffles were repeatedly inserted at the middle of the test tube with inline arrangement to generate vortex flows over the tested tube. Effects of different Reynolds numbers and blockage ratios (b/D, BR with a single pitch ratio of 1 on flow structure in the tested tube were emphasized. The flows in baffled tube show periodic flow at x/D ≈ 2-3, and become a fully developed periodic flow profiles at x/D ≈ 6-7, depending on Re, BR and transverse plane positions. The computational results reveal that the higher of BR and closer position of turbulators, the faster of fully developed periodic flow profiles.

Experimental investigation of effect of flow attack angle on thermohydraulic performance of air flow in a rectangular channel with discrete V-pattern baffle on the heated plate

Directory of Open Access Journals (Sweden)

Raj Kumar

2016-05-01

Full Text Available In this work, the effect of angle of attack ( α a of the discrete V-pattern baffle on thermohydraulic performance of rectangular channel has been studied experimentally. The baffle wall was constantly heated and the other three walls of the channel were kept insulated. The experimentations were conducted to collect the data on Nusselt number ( N u b and friction factor ( f b by varying the Reynolds number (Re = 3000–21,000 and angle of attack ( α a from 30° to 70°, for the kept values of relative baffle height ( H b / H = 0 . 50 , relative pitch ratio ( P b / H = 1 . 0 , relative discrete width ( g w / H b = 1 . 5 and relative discrete distance ( D d / L v = 0 . 67 . As compared to the smooth wall, the V-pattern baffle roughened channel enhances the Nusselt number ( N u b and friction factor ( f b by 4.2 and 5.9 times, respectively. The present discrete V-pattern baffle shapes with angle of attack ( α a of 60° equivalent to flow Reynolds number of 3000 yields the greatest thermohydraulic performance. Discrete V-pattern baffle has improved thermal performance as compared to other baffle shapes’ rectangular channel.

Numerical Investigation of Effects of Inlet Placement and Characteristics of Baffles in Settling Tanks

Directory of Open Access Journals (Sweden)

Hamid Shamloo

2012-12-01

Full Text Available Settling tanks are one of the main parts of treatment plants and different parameters are effective in the settling tank performance. In this study effects of some of these parameters such as the situation of the inlet opening as well as the existence and position of baffles in the tanks are investigated.  2D numerical simulations of primary settling tanks are carried out using 2D Fluent software and the best position for the  inlet to enhance  the  their performance found  to be in the middle of the tank  with optimum size  of the baffle about 30% the height of settling tank  at a distance about 5-10% settling tank's length.

An exploratory study of three-dimensional MP-PIC-based simulation of bubbling fluidized beds with and without baffles

DEFF Research Database (Denmark)

Yang, Shuai; Wu, Hao; Lin, Weigang

2018-01-01

In this study, the flow characteristics of Geldart A particles in a bubbling fluidized bed with and without perforated plates were simulated by the multiphase particle-in-cell (MP-PIC)-based Eulerian-Lagrangian method. A modified structure-based drag model was developed based on our previous work....... Other drag models including the Parker and Wen-Yu-Ergun drag models were also employed to investigate the effects of drag models on the simulation results. Although the modified structure-based drag model better predicts the gas-solid flow dynamics of a baffle-free bubbling fluidized bed in comparison...... with the experimental data, none of these drag models predict the gas-solid flow in a baffled bubbling fluidized bed sufficiently well because of the treatment of baffles in the Barracuda software. To improve the simulation accuracy, future versions of Barracuda should address the challenges of incorporating the bed...

Modelos

OpenAIRE

Aroca Hernández-Ros, Ricardo

2000-01-01

Para estudiar las estructuras se recurre a modelos más o menos simplificados más manejables que la cruda realidad. Una vez formulado un modelo nunca hay que olvidar que el modelo es en sí mismo un sistema de información en el que sólo existe lo que tiene cabida en el sistema. Debe cuidarse por tanto al formularlo que no haya aspectos relevantes de la realidad no considerados ya que ello conduciría a graves discrepancias aunque todo el manejo matemático del modelo sea perfecto.

Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing

International Nuclear Information System (INIS)

AbuRomia, M.M.; Chu, A.W.; Cho, S.M.

1976-01-01

Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle. The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated. The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels. The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle. The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry. The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle. The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits. The effect of flow maldistribution, present on the tube or shell sides of the heat exchangers, in altering the temperature field of tube bundles is also noted

Optimum radii and heights of U-shaped baffles in a square duct heat exchanger using surrogate-assisted optimization

Directory of Open Access Journals (Sweden)

Kittinan Wansasueb

2017-06-01

Full Text Available In this paper, optimum U-shaped baffles in a square channel heat exchanger using air as a working fluid were developed using surrogate-assisted optimization. The design problem is set to maximize heat transfer performance and simultaneously minimize pressure loss across the channel. Design variables determine the radii and heights of the baffles, whereas the optimization problem is treated as box-constrained optimization. The work in this paper is aimed at finding an appropriate surrogate model for designing such a heat exchanger system. Function evaluations are performed by means of computational fluid dynamics (CFD. The computations are based on the finite volume method and are carried out at a Reynolds number of 4000. It has been found that the use of U-shaped baffles as heat transfer enhancement devices improves the thermal performance of the heat exchanger. Comparative results reveal that the Kriging model is the most accurate surrogate model, however, the surrogate model giving the best result is support vector regression.

Sensing performance analysis on Fano resonance of metallic double-baffle contained MDM waveguide coupled ring resonator

Science.gov (United States)

Chen, Ying; Luo, Pei; Liu, Xiaofei; Di, Yuanjian; Han, Shuaitao; Cui, Xingning; He, Lei

2018-05-01

Based on the transmission property and the photon localization characteristic of the surface plasmonic sub-wavelength structure, a metallic double-baffle contained metal-dielectric-metal (MDM) waveguide coupled ring resonator is proposed. Like the electromagnetically induced transparency (EIT), the Fano resonance can be achieved by the interference between the metallic double-baffle resonator and the ring resonator. Based on the coupled mode theory, the transmission property is analyzed. Through the numerical simulation by the finite element method (FEM), the quantitative analysis on the influences of the radius R of the ring and the coupling distance g between the metallic double-baffle resonator and the ring resonator for the figure of merit (FOM) is performed. And after the structure parameter optimization, the sensing performance of the waveguide structure is discussed. The simulation results show that the FOM value of the optimized structure can attain to 5.74 ×104 and the sensitivity of resonance wavelength with refractive index drift is about 825 nm/RIU. The range of the detected refractive index is suitable for all gases. The waveguide structure can provide effective theoretical references for the design of integrated plasmonic devices.

Method of calculation of new cyclone-type separator with swirling baffle and bottom take off of clean gas - part II: experimental verification

Energy Technology Data Exchange (ETDEWEB)

Chmielniak, T.; Bryczkowski, A. [Inst. for Chemical Processing of Coal, Zabrze (Poland)

2001-05-01

The results of tests and experimental verification of the derived model to predict collection efficiency and pressure drop of the Institute for Chemical Processing of Coal (IChPW) design of a cyclone-type separator with a swirling baffle are presented. The experimental work contains the testing of the effect of gas flow rate and rotational speed of the rotor on separation efficiency and pressure drop. The effect of sealing flow on dedusting efficiency was also tested. The separator with a swirling baffle is characterized by high efficiency and low pressure drop. Higher dedusting efficiency and lower pressure drop can be obtained by extension of the baffle height. The calculational method shows good agreement with the experiments.

Wastewater treatment in a hybrid activated sludge baffled reactor

Energy Technology Data Exchange (ETDEWEB)

Tizghadam, Mostafa [Laboratoire des Sciences de l' Eau et de l' Environnement, Universite de Limoges, ENSIL, Parc ESTER, 16 Rue Atlantis, F-87068 Limoges Cedex (France); Dagot, Christophe [Laboratoire des Sciences de l' Eau et de l' Environnement, Universite de Limoges, ENSIL, Parc ESTER, 16 Rue Atlantis, F-87068 Limoges Cedex (France)], E-mail: dagot@ensil.unilim.fr; Baudu, Michel [Laboratoire des Sciences de l' Eau et de l' Environnement, Universite de Limoges, ENSIL, Parc ESTER, 16 Rue Atlantis, F-87068 Limoges Cedex (France)

2008-06-15

A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98 {+-} 2% of the total COD and 98 {+-} 2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593 {+-} 11 mg COD/L and 43 {+-} 5 mg N/L, respectively, at a HRT of 10 h. These results were 93 {+-} 3 and 6 {+-} 3% for the CAS reactor, respectively. Approximately 90 {+-} 7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654 {+-} 16 mg COD/L at a 3 h HRT, and in the organic loading rate (OLR) of 5.36 kg COD m{sup -3} day{sup -1}. The result for the CAS reactor was 60 {+-} 3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank.

Investigations of the Gas-Liquid Multiphase System Involving Macro-Instability in a Baffled Stirred Tank Reactor

Directory of Open Access Journals (Sweden)

Shuo Zhang

2016-01-01

Full Text Available Bubble Sauter Mean Diameter (SMD in gas-liquid multiphase system is of particular interest and the quantification of gas characteristics is still a challenge today. In this contribution, multiphase Computational Fluid Dynamic (CFD simulations are combined with Population Balance Model (PBM to investigate the bubble SMD in baffled stirred tank reactor (STR. Hereby, special attention is given to the phenomenon known as the fluid macro-instability (MI, which is a large-scale low-frequency fluid velocity variation in baffled STRs, since the fluid MIs have a dominating influence on the bubble breakage and coalescence processes. The simulations, regarding the fluid velocity, are validated with Laser Doppler Anemometry (LDA experiments, in which the instant radial velocity is analyzed through Fast Fourier Transform (FFT spectrum. The frequency peaks of the fluid MIs are found both in the simulation and in the experiment with a high degree of accuracy. After the validation, quantitative predictions of overall bubble SMD with and without MIs are carried out. Due to the accurate prediction of the fluid field, the influence of the fluid MI to bubble SMD is presented. This result provides more adequate information for engineers working in the field of estimating bubble SMDs in baffled STRs.

Experimental investigation on a semi-circular trough-absorber solar still with baffles for fresh water production

International Nuclear Information System (INIS)

Sathyamurthy, Ravishankar; Nagarajan, P.K.; El-Agouz, S.A.; Jaiganesh, V.; Sathish Khanna, P.

2015-01-01

Highlights: • Experiments are carried out to analyze the performance. • Baffles are placed in the absorber to increase the residence time of water with solar intensity. • Yield of fresh water from present solar still is 16.66% more than a conventional solar still. • Payback period of the present model is quicker. - Abstract: The main objective of this research is to increase the contact time of water in the basin to enhance yield of fresh water by using a semicircular absorber solar still with baffles. An experimental as well as theoretical investigation is carried out. The productivity and efficiency of present still are analyzed with the influence of the number baffles and the water flow rate. A good agreement between the experimental and theoretical results is observed. The results indicate that, the daily yield of present solar still is higher than that for conventional still approximately by 16.66%. The outlet water temperature present solar still is high subsequently, it can be coupled with multi-state of solar stills to increase productivity. Therefore, the present solar still can be sufficiently extended for other continuous solar desalination systems. Economic analysis concluded that, the payback period of the present model solar still is quicker while comparing it with other solar still

Analysis of a double pipe heat exchanger performance by use of porous baffles and pulsating flow

International Nuclear Information System (INIS)

Targui, N.; Kahalerras, H.

2013-01-01

Highlights: • A double pipe heat exchanger performance is numerically studied. • Use of porous baffles and pulsating flow to enhance heat exchanger efficiency. • The governing equations are solved by the control volume method. • The efficiency increases with the amplitude and frequency of pulsation. • The highest values of are obtained when only hot fluid is pulsating (Case3). - Abstract: A numerical investigation is carried out to analyze the effect of porous baffles and flow pulsation on a double pipe heat exchanger performance. The hot fluid flows in the inner cylinder, whereas the cold fluid circulates in the annular gap. The Darcy–Brinkman–Forchheimer model is adopted to describe the flow in the porous regions and the finite volume method is used to solve the governing equations with the appropriate boundary conditions. The effects of the amplitude and frequency of pulsation, as well as the porous baffles permeability on the flow structure and the heat exchanger efficiency are analyzed. The results reveal that the addition of an oscillating component to the mean flow affects the flow structure, and enhances the heat transfer in comparison to the steady non pulsating flow. The highest heat exchanger performance is obtained when only the flow of the hot fluid is pulsating

Post-Service Examination of PWR Baffle Bolts, Part I. Examination and Test Plan

Energy Technology Data Exchange (ETDEWEB)

Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-04-30

In support of extended service and current operations of the US nuclear reactor plants, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating with Ginna Nuclear Power Plant, The Westinghouse Electric Company, LLC, and ATI Consulting, the selective procurement of baffle bolts that were withdrawn from service in 2011 and currently stored on site at Ginna. The goal of this program is to perform detailed microstructural and mechanical property characterization of baffle former bolts following in-service exposures. This report outlines the selection criteria of the bolts and the techniques to be used in this study. The bolts available are the original alloy 347 steel fasteners used in holding the baffle plates to the baffle former structures within the lower portion of the pressurized water reactor vessel. Of the eleven possible bolts made available for this work, none were identified to have specific damage. The bolts, however, did show varying levels of breakaway torque required in their removal. The bolts available for this study varied in peak fluence (highest dose within the head of the bolt) between 9.9 and 27.8x10²¹ n/cm² (E>1MeV). As no evidence for crack initiation was determined for the available bolts from preliminary visual examination, two bolts with the higher fluence values were selected for further post-irradiation examination. The two bolts showed different breakaway torque levels necessary in their removal. The information from these bolts will be integral to the LWRS program initiatives in evaluating end of life microstructure and properties. Furthermore, valuable data will be obtained that can be incorporated into model predictions of long-term irradiation behavior and compared to results obtained in high flux experimental reactor conditions. The two bolts selected for the ORNL study will be shipped to Westinghouse with bolts of

Ultraviolet and visible BRDF data on spacecraft thermal control and optical baffle materials

Science.gov (United States)

Viehmann, W.; Predmore, R. E.

1987-01-01

Bidirectional scattering functions of numerous optical baffle materials and of spacecraft thermal control coatings and surfaces are presented. Measurements were made at 254 nm and at 633 nm. The coatings and surfaces include high-reflectance white paints, low-reflectance optical blacks, thermal control blankets, and various conversion coatings on aluminum.

Inspection and replacement of baffle assembly screws inside American reactor vessels

International Nuclear Information System (INIS)

Neal, K.; Chaumont, J.C.

1999-01-01

The baffle assembly inside the vessel of a 900 MWe reactor designed by Framatome, is made up of 44 plates fixed on 8 horizontal supports by a system of about 1000 screws. These plates undergo high neutron flux and the problem of screw cracking appeared at the end of the eighties in the first-generation reactors. The first operation on a large scale concerning the screws of a Westinghouse type reactor, was performed on the Tihange-1 power plant where Framatome controlled 960 screws and replaced 91. In 1997 as a consequence of the Belgian and French feedback experience, American plant operators launched a vast program of preventive actions: material analysis, inspection of baffle plate screws and replacement of defective screws. This program was held in cooperation with EPRI (electric power research institute) and under the control of NRC (nuclear regulatory commission). Framatome Technologies Inc (FTI) was in charge of the in-situ inspection and replacement of the screws. FTI designed special tools and equipment adapted to the 2-loop American reactors but the basis ideas were those applied on the Tihange reactor. The successful experience of FTI has allowed the firm to be commissioned for 6 2-loops American reactors. (A.C.)

Scale up of diesel oil biodegradation in a baffled roller bioreactor.

Science.gov (United States)

Nikakhtari, Hossein; Song, Wanning; Kumar, Pardeep; Nemati, Mehdi; Hill, Gordon A

2010-05-01

Diesel oil is a suitable substance to represent petroleum contamination from accidental spills in operating and transportation facilities. Using a microbial culture enriched from a petroleum contaminated soil, biodegradation of diesel oil was carried out in 2.2, 55, and 220 L roller baffled bioreactors. The effects of bioreactor rotation speed (from 5 to 45 rpm) and liquid loading (from 18% to 73% of total volume) on the biodegradation of diesel oil were studied. In the small scale bioreactor (2.2L), the maximum rotation speed of 45 rpm resulted in the highest biodegradation rate with a first order biodegradation kinetic constant of 0.095 d(-1). In the larger scale bioreactors, rotation speed did not affect the biodegradation rate. Liquid loadings higher than 64% resulted in reduced biodegradation rates in the small scale bioreactor; however, in the larger roller bioreactors liquid loading did not affect the biodegradation rate. Biodegradation of diesel oil at 5 rpm and 73% loading is recommended for operating large scale roller baffled bioreactors. Under these conditions, high diesel oil concentrations up to 50 gL(-1) can be bioremediated at a rate of 1.61 gL(-1)d(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Wastewater treatment in a hybrid activated sludge baffled reactor

International Nuclear Information System (INIS)

Tizghadam, Mostafa; Dagot, Christophe; Baudu, Michel

2008-01-01

A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98 ± 2% of the total COD and 98 ± 2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593 ± 11 mg COD/L and 43 ± 5 mg N/L, respectively, at a HRT of 10 h. These results were 93 ± 3 and 6 ± 3% for the CAS reactor, respectively. Approximately 90 ± 7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654 ± 16 mg COD/L at a 3 h HRT, and in the organic loading rate (OLR) of 5.36 kg COD m -3 day -1 . The result for the CAS reactor was 60 ± 3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank

TEM study of radiation induced defects in baffle-former-barrel assembly from decommissioned NPP Greifswald

International Nuclear Information System (INIS)

Srba, O.; Michalicka, J.; Keilova, E.; Kocik, K.

2013-06-01

A complex transmission electron microscopy (TEM) study of reactor vessel internal (RVI) materials from the baffle-former-barrel assembly from NPP Greifswald (VVER 440), Unit 1 decommissioned after 15 service cycles has been undertaken. All parts of the baffle-former-barrel assembly are made from Ti-stabilized austenitic stainless steel 08Ch18N10T. The materials were exposed to different dose of neutron radiation (2.4 - 11.4 dpa) at temperatures 267 - 398 deg. C depending on position in the core. Three types of radiation induced defects were identified and quantified, namely: dislocations, cavities (voids) and fine-scaled precipitated particles of Ni-Si rich phases. Black-dot type defects were observed too. Operation conditions are around ≅ 300 deg. C that is why we have observed defect typical for both low and high regions of irradiation temperatures. (authors)

Performance improvement of a hybrid air conditioning system using the indirect evaporative cooler with internal baffles as a pre-cooling unit

Directory of Open Access Journals (Sweden)

A.E. Kabeel

2017-12-01

Full Text Available In the present paper, the effects of the indirect evaporative cooler with internal baffle on the performance of the hybrid air conditioning system are numerically investigated. The hybrid air conditioning system contains two indirect evaporative coolers with internal baffle, one is utilized to pre-cool the air inlet to the desiccant wheel and the other is utilized to pre-cool the supply air inlet to the room. The effects of the inlet conditions of the process and reactivation air and working air ratio on the thermal performance of the hybrid air conditioning system have been analyzed. The results of this study show that in the hybrid air conditioning system for using the indirect evaporative cooler with internal baffle as a pre-cooling unit, the supply air temperature reduced by 21% and the coefficient of performance improved by 71% as compared to previous designs of the hybrid air conditioning system at the same inlet conditions. For increasing process air inlet temperature from 25 °C to 45 °C, supply air temperature increases from 12.7 °C to 14.2 °C, thermal COP increases from 1.87 to 2.84, and supply air relative humidity increases from 76.7% to 77.4%. Also, for increasing the reactivation air inlet temperature from 70 °C to 110 °C, supply air temperature dropped from 15.9 °C to 10.9 °C, supply air relative humidity dropped from 82.7% to 71.8%, and thermal COP dropped from 4.5 to 1.7. The recommended optimal air working ratio in the indirect evaporative cooler with internal baffle should be 0.15. Keywords: Desiccant material, Solar air collector, Evaporative cooler, Internal baffles, Air conditioning

Supply of a prototype component for the ITER divertor baffle

International Nuclear Information System (INIS)

Bobin-Vastra, I.; Febvre, M.; Schedler, B.; Ploechl, L.; Bouveret, Y.; Cauvin, D.; Raisson, G.; Merola, M.

2001-01-01

The ITER divertor baffle is one of the Plasma facing components which are developed in the frame of the ITER concept. The supply consisted in the manufacturing of four panels with four First Wall geometries using macroblock or heat sink+armour concepts. DS-Copper, and CuCrZr were the materials for the heat sink, and CFC or Tungsten Plasma spray were the armour. The panels included two Copper-based tubes each. The final purpose is the comparison of the fabricability of each type and the performances of each panel under heat fluxes

The numerical simulation of the performances of water rotors used in pipelines with the water baffle plates

International Nuclear Information System (INIS)

Altan, Burcin Deda

2014-01-01

In this study, obtaining energy especially from large and medium sized pipelines used for drinking water, rain water, or even some used for waste water has been aimed. In line with this objective, it has been investigated how to increase the performance of the water rotors used in the pipelines in order to benefit optimally from the energy of the flowing fluid in pipe. Furthermore, in order to increase the performance of the water rotor used in pipelines, a water baffle plate has been placed in front of the water rotor. In this way, the effects of size parameters of the water rotor used in the pipeline in conjunction with the various design parameters of the water baffle plate on the power performance of rotor has been investigated. By comparing design parameters, the number of the water rotor blades has also been investigated. Optimization steps have been carried out with numerical results of the study supported by theoretical computation. For numerical optimization of the water rotor, both static and dynamic performances of rotor have been found. According to the optimization study, the maximum power performance values have been obtained from a power pipe unit which consists of a water rotor and a water baffle plate with (x g /r r = 0.1, y g /r r = 0.4, ve r r /r p = 0.4 ve α = 60 .deg. ) size ratios.

Preservation of Thermal Control Specular Gold Baffle Surface on the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) Electronics Compartment (IEC)

Science.gov (United States)

MonteedeGarcia, Kristina; Patel, Jignasha; Perry, Radford, III

2010-01-01

Extremely tight thermal control property degradation allowances on the vapor-deposited, gold-coated IEC baffle surface, made necessary by the cryogenic JWST Observatory operations, dictate tight contamination requirements on adjacent surfaces. Theoretical degradation in emittance with contaminant thickness was calculated. Maximum allowable source outgassing rates were calculated using worst case view factors from source to baffle surface. Tight requirements pushed the team to change the design of the adjacent surfaces to minimize the outgassing sources

Studies of high-δ (baffled) and low-δ (open) pumped divertor operation on DIII-D

International Nuclear Information System (INIS)

Allen, S.L.; Fenstermacher, M.E.; Greenfield, C.M.

1998-08-01

The authors report new experimental results with the RDP-OB (Radiative Divertor Project-outer baffle) and cryopump in both upper single-null (USN) and double-null (DN) ELMing H-mode discharges. The baffled divertor reduced the core ionization (∼2--2.5x), in reasonable agreement with predictions from UEDGE/DEGAS modeling (∼3.75x). The upper cryopump achieved density control of n e /n gw ∼ 0.22 (line density/Greenwald density) with Z eff ∼ 2 in high-δ plasmas. The measured exhaust is comparable to the lower pump, except at lower core electron densities (n e 19 m -3 ). Efficient impurity exhaust was obtained with deuterium SOL flow. Preliminary experiments with DN operation has shown that the particle exhaust to the upper pump depends on the up/down magnetic balance. Preliminary experiments indicate that the DN exhaust is roughly 40--50% of the USN exhaust at n e ∼ 4 x 10 19 m -3

Aeroelastic Dynamics Simulation of Two BaffleBased Connected Shells

Directory of Open Access Journals (Sweden)

G. A. Shcheglov

2015-01-01

Full Text Available The present work is an extention study of aeroelastic vibrations of thin-walled structures with a spatial subsonic flow. An original algorithm for solving complex conjugated aeroelasticity problem, allowing to carry out direct numerical simulation of structural oscillations in the spatial flow of an incompressible medium are developed and tested. On the basis of this simulation study of the spectrum comes the driving forces acting on the flow in a spatial component elastic structure mounted on an impenetrable screen.Currently, updating the mathematical models of unsteady loads that act on the spacepurpose elastic designs such as launch vehicles, service tower installed on the launch pad is a challenge. We consider two thin-walled cantilevered rotating shells connected by a system of elastic couplings, installed next to the impenetrable baffle so that the axes of rotation are perpendicular to the baffle. Dynamics of elastic system is investigated numerically, using the vortex element method with the spatial separated flow of an incompressible medium. A feature of the algorithm is the common commercial complex MSC Patran / Nastran which is used in preparing data to calculate the shell dynamics thereby allowing to consider very complex dynamic schemes.The work performs the first calculations of the model problem concerning the forced oscillations of two coupled cylindrical shells in the flow of an incompressible medium. Comparing the load spectra for the elastic and absolutely rigid structure has shown that the frequency spectra vary slightly. Further calculations are required in which it will be necessary to increase the duration of the calculations, sampling in construction of design scheme, and given the large number of vibration modes that require increasing computing power.Experience in calculating aeroelastic dynamics of complex elastic structures taking into account the screen proved to be successful as a whole, thereby allowing to turn to

The numerical simulation of the performances of water rotors used in pipelines with the water baffle plates

Energy Technology Data Exchange (ETDEWEB)

Altan, Burcin Deda [Pamukkale University, Kinikli (Turkmenistan)

2014-11-15

In this study, obtaining energy especially from large and medium sized pipelines used for drinking water, rain water, or even some used for waste water has been aimed. In line with this objective, it has been investigated how to increase the performance of the water rotors used in the pipelines in order to benefit optimally from the energy of the flowing fluid in pipe. Furthermore, in order to increase the performance of the water rotor used in pipelines, a water baffle plate has been placed in front of the water rotor. In this way, the effects of size parameters of the water rotor used in the pipeline in conjunction with the various design parameters of the water baffle plate on the power performance of rotor has been investigated. By comparing design parameters, the number of the water rotor blades has also been investigated. Optimization steps have been carried out with numerical results of the study supported by theoretical computation. For numerical optimization of the water rotor, both static and dynamic performances of rotor have been found. According to the optimization study, the maximum power performance values have been obtained from a power pipe unit which consists of a water rotor and a water baffle plate with (x{sub g} /r{sub r} = 0.1, y{sub g}/r{sub r} = 0.4, ve r{sub r}/r{sub p} = 0.4 ve α = 60 .deg. ) size ratios.

Radial midframe baffle for can-annular combustor arrangement having tangentially oriented combustor cans

Science.gov (United States)

Rodriguez, Jose L.

2015-09-15

A can-annular gas turbine engine combustion arrangement (10), including: a combustor can (12) comprising a combustor inlet (38) and a combustor outlet circumferentially and axially offset from the combustor inlet; an outer casing (24) defining a plenum (22) in which the combustor can is disposed; and baffles (70) configured to divide the plenum into radial sectors (72) and configured to inhibit circumferential motion of compressed air (16) within the plenum.

Influence of presence of inclined centered baffle and corrugation frequency on natural convection heat transfer flow of air inside a square enclosure with corrugated side walls

Energy Technology Data Exchange (ETDEWEB)

Hussain, Salam Hadi; Jabbar, Mohammed Yousif; Mohamad, Ahmad Saddy [Mechanical Engineering Department, College of Engineering, Babylon University, Babylon Province (Iraq)

2011-09-15

The main objective of this study is to investigate the effect of presence of insulated inclined centered baffle and corrugation frequency on the steady natural convection in a sinusoidal corrugated enclosure. The present study is based on such a configuration where the two vertical sinusoidal walls are maintained at constant low temperature whereas a constant heat flux source whose length is 80% of the width of the enclosure is discretely embedded in the bottom wall. The remaining parts of the bottom wall and the top wall are adiabatic. The finite volume method has been used to solve the governing Navier-Stokes and the energy conservation equations of the fluid medium in the enclosure in order to investigate the effects of baffle inclination angles, corrugation frequencies and Grashof numbers on the fluid flow and heat transfer in the enclosure. The values of the governing parameters are the Grashof number Gr (10{sup 3}-10{sup 6}), the corrugation frequencies CF (1, 2 and 3), baffle inclination angles (0 deg. {<=} {phi} {<=} 150 deg.) and Prandtl number Pr (0.71). Results are presented in the form of streamline and isotherm plots. The results of this investigation are illustrated that the average Nusselt number increases with increase in both the Grashof number and corrugation frequency for different baffle inclination angles and the presence of inclined baffle and increasing the corrugation frequency have significant effects on the average Nusselt numbers, streamlines and isotherms inside the enclosure. The obtained numerical results have been compared with literature ones, and it gives a reliable agreement. (authors)

Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries.

Science.gov (United States)

Sabry, Tarek

2010-02-15

A new concept for a low-cost modified septic tank, named Upflow Septic Tank/Baffled Reactor (USBR), was constructed and tested in a small village in Egypt. During almost one year of continuous operation and monitoring, this system was found to have very satisfactory removal results, where the average results of COD, BOD, and TSS removal efficiencies were 84%, 81%, and 89%, respectively, and the results of the experiment proved that the second compartment (Anaerobic Baffled Reactor) was the main treatment unit in removing the pollutants during the start-up period and at the very early steady-state stage. However, after this period and during the steady-state operation conditions, the second compartment served as a polishing step. Also, it was observed that the USBR system was not affected by the imposed shock loads at the peak flow and organic periods. The results showed that the system is slightly influenced by the drop in the temperature. Decreasing in BOD and COD removal by factor of 9% was observed, when temperature decreases from the average of 35 degrees C in summer time (for the first 127 days) to the average of 22 degrees C in winter time (between day 252 and day 280). Whereas, the TSS removals were not affected by the drop in temperature. The results of the sewage flow variations during one year of operation were compared with Goodrich Formula to see the applicability of this equation in rural developing countries. MAIN FINDING OF THE WORK: The Upflow Septic Tank/Baffled Reactor system could become a promising alternative to the conventional treatment plants in rural developing countries.

Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries

International Nuclear Information System (INIS)

Sabry, Tarek

2010-01-01

A new concept for a low-cost modified septic tank, named Upflow Septic Tank/Baffled Reactor (USBR), was constructed and tested in a small village in Egypt. During almost one year of continuous operation and monitoring, this system was found to have very satisfactory removal results, where the average results of COD, BOD, and TSS removal efficiencies were 84%, 81%, and 89%, respectively, and the results of the experiment proved that the second compartment (Anaerobic Baffled Reactor) was the main treatment unit in removing the pollutants during the start-up period and at the very early steady-state stage. However, after this period and during the steady-state operation conditions, the second compartment served as a polishing step. Also, it was observed that the USBR system was not affected by the imposed shock loads at the peak flow and organic periods. The results showed that the system is slightly influenced by the drop in the temperature. Decreasing in BOD and COD removal by factor of 9% was observed, when temperature decreases from the average of 35 deg. C in summer time (for the first 127 days) to the average of 22 deg. C in winter time (between day 252 and day 280). Whereas, the TSS removals were not affected by the drop in temperature. The results of the sewage flow variations during one year of operation were compared with Goodrich Formula to see the applicability of this equation in rural developing countries. Main finding of the work: The Upflow Septic Tank/Baffled Reactor system could become a promising alternative to the conventional treatment plants in rural developing countries.

Integración de un Modelo S&OP con un Modelo ALM

OpenAIRE

Insuasty Chamorro, Andrés Felipe

2015-01-01

DecisionWare International Corp. (DW) Este trabajo presenta los fundamentos metodológicos y la aplicación de la integración de un modelo financiero ALM (Assets Liabilities Management) con los modelos de planificación de la cadena de oferta de una empresa industrial global como son el SCD (Supply Chain Design) y el S&OP (Sales & Operation Planning). La aplicación en este trabajo se concentra en el modelo S&OP vinculado a un modelo ALM. Como resultado práctico se presenta la implementación d...

The energy-saving anaerobic baffled reactor membrane bioreactor (EABR-MBR) system for recycling wastewater from a high-rise building.

Science.gov (United States)

Ratanatamskul, Chavalit; Charoenphol, Chakraphan

2015-01-01

A novel energy-saving anaerobic baffled reactor-membrane bioreactor (EABR-MBR) system has been developed as a compact biological treatment system for reuse of water from a high-rise building. The anaerobic baffled reactor (ABR) compartment had five baffles and served as the anaerobic degradation zone, followed by the aerobic MBR compartment. The total operating hydraulic retention time (HRT) of the EABR-MBR system was 3 hours (2 hours for ABR compartment and very short HRT of 1 hour for aerobic MBR compartment). The wastewater came from the Charoen Wisawakam building. The results showed that treated effluent quality was quite good and highly promising for water reuse purposes. The average flux of the membrane was kept at 30 l/(m2h). The EABR-MBR system could remove chemical oxygen demand, total nitrogen and total phosphorus from building wastewater by more than 90%. Moreover, it was found that phosphorus concentration was rising in the ABR compartment due to the phosphorus release phenomenon, and then the concentration decreased rapidly in the aerobic MBR compartment due to the phosphorus uptake phenomenon. This implies that phosphorus-accumulating organisms inside the EABR-MBR system are responsible for biological phosphorus removal. The research suggests that the EABR-MBR system can be a promising system for water reuse and reclamation for high-rise building application in the near future.

Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

Energy Technology Data Exchange (ETDEWEB)

Sumantri, Indro; Purwanto,; Budiyono [Chemical Engineering Department, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto, SH, Kampus Baru Tembalang, Semarang (Indonesia)

2015-12-29

The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration.

Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

International Nuclear Information System (INIS)

Sumantri, Indro; Purwanto,; Budiyono

2015-01-01

The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration

Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

Science.gov (United States)

Sumantri, Indro; Purwanto, Budiyono

2015-12-01

The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration.

PERTURBACIONES EN MODELOS COSMOLOGICOS INFLACIONARIOS

OpenAIRE

CID MUÑOZ; MARIA ANTONELLA; CID MUÑOZ; MARIA ANTONELLA

2010-01-01

Mostramos el desarrollo de la teoría de Relatividad General y el surgimiento a partir de ella del primer modelo cosmológico parcialmente exitoso en describir el universo observado, el modelo cosmológico estándar. Exponemos los problemas de este modelo al intentar describir el universo temprano y cómo éstos encuentran solución en el contexto de los modelos inflacionarios. Mostramos cómo los modelos inflacionarios son capaces de proveer una explicación razonable para el origen de las estruct...

Numerical analysis of blast flow-field of baffle type muzzle brake

Energy Technology Data Exchange (ETDEWEB)

Kim, D.H. [Graduate School, Chungnam National University, Taejon (Korea); Ko, S. [Chungnam National University, Taejon (Korea)

1998-11-01

A three-dimensional unsteady, inviscid blast flow-field of a baffle type muzzle brake has been simulated by solving the Euler equation. The blast flow-field includes the effect of the free air blast, precursor blast flow and the propellant blast gas flow. Chimera grid scheme was used to generate 9 multi-block volume grids for the complex geometry. The evolution of the blast flow-field is presented by showing the contours of pressure, density and Mach number for certain time step. The comparison of the calculated and measured peak pressures on the surfaces of the muzzle brake is also presented. (author). 4 refs., 5 figs., 1 tab.

Rapid production of biodiesel in mesoscale oscillatory baffled reactors

Energy Technology Data Exchange (ETDEWEB)

Phan, A.N.; Harvey, A.P.; Eze, V. [School of Chemical Engineering and Advanced Materials, Newcastle Upon Tyne (United Kingdom)

2012-07-15

Continuous alkali-catalyzed transesterification of rapeseed oil with methanol was carried out in three mesoreactor designs. The induction time decreased with oscillatory Reynolds number for all three reactors. Stable steady states were achieved within induction times of 1.5, 2.5, and 4.0 residence times for the integral, wire wool, and helical baffle designs, respectively. Both experimental and simulated results indicated that under the given conditions there is an optimal residence time for homogeneous transesterification. Higher residence times resulted in reduced fatty acid methyl ester content due to the saponification side reaction. The results demonstrate that biodiesel can be produced at an industrially acceptable level of conversion (> 95 %) in < 5 min residence time. This requires a combination of high catalyst concentration and good mixing. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A study of the various baffles used in the Marcoule chimneys and the search for a new model (1961); Etude des differents deflecteurs utilises pour les cheminees de Marcoule et recherche d'un nouveau type de deflecteur (1961)

Energy Technology Data Exchange (ETDEWEB)

Chassany, J [Commissariat a l' Energie Atomique, Centre de Production de Plutonium, Marcoule (France). Centre d' Etudes Nucleaires; Parigi, H [Institut de Mecanique des Fluides de Marseille, 13 (France); Salaun-Penquer, G [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)

1961-07-01

The baffle placed at the top of a chimney determines the shape of the smoke pall for low exit-velocities. The G. 1 type baffle was studied taking into account the characteristics of its collar: totally hollow - partially hollow - solid; on a ribbed chimney or on a plain chimney. The Pu type baffle was also tested. The search for a new type of baffle was limited to variants of the blade - type baffle: - a porous envelope device; - a cone - shaped device and - a deflector of the cupel type. Only the blade-type baffle was rejected, efficient solutions are proposed using the other types or their combinations. (authors) [French] Le deflecteur place au sommet d'une cheminee conditionne l'allure du panache pour les rejets a faible vitesse de sortie. Le deflecteur type Gl a ete etudie en tenant compte de son embase: totalement evidee - partiellement evidee - pleine; sur une cheminee striee et sur une cheminee lisse. Le deflecteur type Pu a ete egalement teste. La recherche d'un nouveau type de deflecteur a porte sur les deflecteurs a aubage: - un dispositif a enveloppe poreuse; - un dispositif en ogive et - le deflecteur en coupelle. Seul le deflecteur a aubage a ete rejete, des solutions efficaces sont proposees avec les autres types ou leur combinaison. (auteurs)

FEM-DBEM approach to analyse crack scenarios in a baffle cooling pipe undergoing heat flux from the plasma

Directory of Open Access Journals (Sweden)

R. Citarella

2017-02-01

Full Text Available Wendelstein 7-X is the world’s largest nuclear fusion experiment of stellarator type, in which a hydrogen plasma is confined by a magnet field generated with external superconducting coils, allowing the plasma to be heated up to the fusion temperature. The water-cooled Plasma Facing Components (PFC protect the Plasma Vessel (PV against radiative and convective heat from the plasma. After the assembly process of heat shields and baffles, several cracks were found in the braze and cooling pipes. Due to heat load cycles occurring during each Operational Phase (OP, thermal stresses are generated in the heat sinks, braze root and cooling pipes, capable to drive fatigue crack-growth and, possibly, a water leak through the pipe thickness. The aim of this study is to assess the most dangerous initial crack configurations in one of the most critical baffles by using numerical models based on a FEM-DBEM approach.

Ultrasonic testing of core baffle former bolts of the core tanks of pressurised water reactors; Ultraschallpruefung von Kernumfassungsschrauben der Kernbehaelter von Druckwasserreaktoren

Energy Technology Data Exchange (ETDEWEB)

Bies, Christian M.; Alaerts, Louis; Bonitz, Frank W. [Westinghouse Electric Germany GmbH, Mannheim (Germany); Devlin, Russell S.; Minogue, Patrick [WesDyne International, Madison, PA (United States)

2013-07-01

This article presents the MIDAS VI testing robot used by Westinghouse / WesDyne. This is a remotely operated underwater vehicle which positions ultrasonic probes under camera control. This vehicle makes it possible to substantially reduce the time required for setting up and preparing ultrasonic tests on core baffle former bolts. It has also accelerated the test procedure itself. Test methods have also been developed for bolt types which were hitherto considered incapable of being tested. One of these methods is based on a phased array probe. The article also reports on experiences gained over the course of years in testing core baffle former bolts in European nuclear power plants using the SUPREEM testing robot.

ITER baffle module small-scale mock-ups: first wall thermo-mechanical testing results

International Nuclear Information System (INIS)

Severi, Y.; Giancarli, L.; Poitevin, Y.; Salavy, J.F.; Le Marois, G.; Roedig, M.; Vieider, G.

1998-01-01

The EU-home team is in charge of the R and D related to the ITER baffle first wall. Five small-scale mock-ups, using Be, CFC and W tiles and different armour/heat-sink material joints under development, have been fabricated and thermomechanically tested in FE200 (Le Creusot) and JUDITH (Juelich) electron beam facilities. The small-scale mock-ups have been submitted to thermo-mechanical fatigue tests (up to failure using accelerating techniques). The objective was to determine the performances of the armour material joints under high heat flux cycles. (orig.)

Active control of radiated sound power from a baffled, rectangular panel

DEFF Research Database (Denmark)

Mørkholt, Jakob

1996-01-01

with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained over......Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... a broad frequency range using few piezoceramic actuators, provided that an accurate estimate of the sound power is available for minimisation....

Contraste de un modelo de envejecimiento exitoso derivado del modelo de Roy

Directory of Open Access Journals (Sweden)

María Amparo Kantún Marín

2017-01-01

Full Text Available Se formula y contrasta un modelo de envejecimiento exitoso derivado del modelo de adaptación de Roy. Se analizó una muestra no probabilística de 255 adultos mayores de seis centros sociales y un centro médico de consulta externa en Nuevo León, México. Se usó un modelamiento de ecuaciones estructurales. En el modelo final los estímulos focales de autopercepción del envejecimiento, entorno peatonal inmediato y el estímulo contextual de síntomas depresivos incidieron sobre el afrontamiento, que a su vez predijo el envejecimiento exitoso. El modelo tuvo buen ajuste al añadirse dos correlaciones entre residuos de medida de afrontamiento y envejecimiento exitoso. Los resultados obtenidos sugieren que el afrontamiento es un indicador directo del envejecimiento activo.

Radiative and SOL experiments in open and baffled divertors on DIII-D

International Nuclear Information System (INIS)

Allen, S.L.; Brooks, N.H.; Bastasz, R.

1998-11-01

The authors present recent progress towards an understanding of the physical processes in the divertor and scrape-off-layer (SOL) plasmas in DIII-D. This has been made possible by a combination of new diagnostics, improved computational models, and changes in divertor geometry. They have focused primarily on ELMing H-mode discharges. The physics of Partially Detached Divertor (PDD) plasmas, with divertor heat flux reduction by divertor radiation enhancement using D 2 puffing, has been studied in 2-D, and a model of the heat and particle transport has been developed that includes conduction, convection, ionization, recombination, and flows. Plasma and impurity particle flows have been measured with Mach probes and spectroscopy and these flows have been compared with the UEDGE model. The model now includes self-consistent calculations of carbon impurities. Impurity radiation has been increased in the divertor and SOL with puff and pump techniques using SOL D 2 puffing, divertor cryopumping, and argon puffing. The important physical processes in plasma-wall interactions have been examined with a DiMES probe, plasma characterization near the divertor plate, and the REDEP code. Experiments comparing single-null (SN) plasma operation in baffled and open divertors have demonstrated a change in the edge plasma profiles. These results are consistent with a reduction in the core ionization source calculated with UEDGE. Divertor particle control in ELMing H-mode with pumping and baffling has resulted in reduction in H-mode core densities to n e /n gw ∼ 0.25. Divertor particle exhaust and heat flux has been studied as the plasma shape was varied from a lower SN, to a balanced double null (DN), and finally to an upper SN

Feasibility of an Anaerobic Baffled Reactor (ABR In Treating Starch Industry Wastewater

Directory of Open Access Journals (Sweden)

Ali Assadi

2007-03-01

Full Text Available The anaerobic baffled reactor (ABR includes a mixed anaerobic culture separated into compartments and a novel process with a series of vertical baffles at each compartment. It dose not require granulation for its operation, resulting in shorter start-up time. In this study, the feasibility of the ABR process was investigated for the treatment of wheat flour starch wastewater. Simple gravity settling was used to remove suspended solids from the starch wastewater and used as feed. Start-up of a reactor (13.5L with five compartments using a diluted feed of approximately 4500 mg/L chemical oxygen demand (COD was accomplished in about 9 weeks using seed sludge from the anaerobic digester of a municipal wastewater treatment plant. The reactor with a hydraulic retention time (HRT of 72 h at 35°C and an initial organic loading rate (OLR of 1.2 kgCOD/m3.d showed a removal efficiency of 61% COD. The best reactor performance was observed with an organic loading rate of 2.5 kgCOD/m3.d (or hydraulic retention time of 2.45 d when a COD conversion of 67% was achieved. The main advantage of using an ABR comes from its compartmentalized structure. The first compartment of an ABR may act as a buffer zone to all toxic and inhibitory materials in the feed and, thus, allows the later compartments to be loaded with a relatively harmless, more uniform, and mostly acidified influent. In this respect, the later compartments would be more likely to support active populations of the relatively sensitive methanogenic bacteria.

Sound radiation from a loudspeaker, from a spherical pole cap, and from a piston in an infinite baffle

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2011-01-01

Loudspeakers are often modelled as a rigid piston in an infinite baffle. This model is for real loudspeakers somewhat limited in two ways. One issue is that a loudspeaker is not rigid and a second issue is that a loudspeaker is mostly used in a cabinet. Both issues are addressed here by developing

Traducción del modelo genérico del modelo de negocio a Object-Z

OpenAIRE

Daniele, Marcela; Martellotto, Paola; Baum, Gabriel Alfredo

2005-01-01

Este trabajo muestra el modelo genérico del modelo de negocio [BDMN04], representado gráficamente en términos de UML a través de un diagrama de clases, producto del análisis de los artefactos del Proceso Unificado que componen el modelo de negocio y sus relaciones. Además, se definen un conjunto de reglas que el modelo debe verificar. Esta demostrado que el modelado gráfico es muy útil para visualizar, especificar, construir y documentar los artefactos de un sistema, brindando un lenguaje ...

Inactivation of Escherichia coli in a baffled pond with attached growth: treating anaerobic effluent under the Sahelian climate.

Science.gov (United States)

Moumouni, D A; Andrianisa, H A; Konaté, Y; Ndiaye, A; Maïga, A H

2016-01-01

This study aimed to investigate and understand the zero-level detection of Escherichia coli (E. coli) at the outlet of an improved waste stabilization pond. Wastewaters were collected from the International Institute for Water and Environmental Engineering (2iE) campus and were subjected to biological treatment. The system included two-stage Anaerobic Reactors followed by a Baffled Pond (AR-BP) with recycled plastic media as a medium for attached growth and a control pond (CP). Three vertical baffles were installed, giving four compartments in the baffled pond (BP). The research was conducted on the pilot scale from March to July 2014, by monitoring E. coli, pH, temperature, dissolved oxygen (DO) and chlorophyll-a in each compartment and at different depths. The results show that E. coli concentrations were lower in top layers of all compartments with an undetectable level in the last compartment up to 0.60 m deep. E. coli mean removal efficiencies and decay rates were achieved by significant difference in BP (4.5 log-units, 9.1 day(-1)) and CP (1.1 log-units, 1.1 day(-1)). Higher values of pH (≥9), temperature (≥32°C), DO (≥ 8 mg/L) and chlorophyll-a (≥ 1000 µg/L) were observed at the surface of BP, whereas lower values were shown at the bottom. Sedimentation combined with the synergetic effects of the physicochemical parameters and environmental factors would be responsible for the inactivation of E. coli in BP. It was concluded that the AR-BP could be applied as an alternative low-cost wastewater treatment technology for developing countries and recommended for reuse of their effluent for restricted peri-urban irrigation.

Sound radiation from a loudspeaker, from a spherical pole cap, and from a piston in an infinite baffle

NARCIS (Netherlands)

Aarts, R.M.; Janssen, A.J.E.M.

2012-01-01

Loudspeakers are often modelled as a rigid piston in an infinite baffle. As a model for real loudspeakers, this approach is limited in two ways. One issue is that a loudspeaker cone is not rigid, and a second issue is that a loudspeaker is mostly used in a cabinet. Both issues are addressed here by

The high integrity design and manufacture of the Heysham II/Torness gas baffle

International Nuclear Information System (INIS)

Armor, J.; Day, B.V.; White, C.M.

1985-01-01

The AGR design used on the Heysham II and Torness power stations requires a gas baffle which is essentially a steel pressure vessel for which one can demonstrate a high degree of integrity. The design, analytical, manufacturing, erection and testing processes which were undertaken to achieve the standard required of the completed assembly are discussed. To this end the vessels were manufactured in purpose-made shops and transported to site, leaving a minimum amount of work to be undertaken at site. Subsequent evaluation has shown a very low probability of failure compared with conventional steel pressure vessels. (author)

COMO EVOLUEM OS MODELOS MENTAIS

Directory of Open Access Journals (Sweden)

A. Tarciso Borges

Full Text Available Resumo: Após revisão da literatura onde se define o conceito de modelo mental, apresentamos resultados de estudo sobre os modelos mentais de eletricidade, magnetismo e eletromagnetismo de seis grupos de indivíduos. Entre estudantes e profissionais com experiências de escolarização diversificadas, foram entrevistadas 56 pessoas. As entrevistas ocorreram enquanto se realizaram experimentos com imãs, eletroímãs e circuitos elétricos simples. Foram identificados quatro modelos de eletricidade, cinco de magnetismo e três para explicar o magnetismo no eletroímã. Apresentamos os dados desse estudo centrando atenção na evolução dos modelos identificados. Em nossa análise, destacamos quais aspectos dos modelos sofrem mudanças significativas à medida que os sujeitos ganham maior compreensão conceituai e experiência com os fenômenos estudados.

Mathematical Model to Compare Egg Production C Modelo Matemático para Comparar Curvas de Produção de Ovos

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FB Fialho

2001-12-01

Full Text Available A segmented polynomial model was used on several egg production curves in an attempt to analyze the differences between the curves in a more descriptive manner. Production curves from different commercial and experimental genetic lines of layers were used. The parameters of the model include the age and level of peak production, rate of decrease in production after the peak and time between start and peak of production. These and other derived variables were compared between the curves using contrasts. The methodology used allowed an easier interpretation of the curves, and the detection of differences in sexual maturity, uniformity and peak of production. This work validates the segmented polynomial model for use in future research dealing with analysis of egg production curves.Um modelo polinomial segmentado foi usado em diversas curvas de produção de ovos, numa tentativa de analisar as diferenças entre as curvas de um modo mais descritivo. Foram usadas curvas de produção de diferentes linhagens comerciais e experimentais de poedeiras. Os parâmetros do modelo incluem a idade e nível do pico de produção, a taxa de decréscimo na produção após o pico e o tempo entre o início e o pico de produção. Essas e outras variáveis derivadas pelo modelo foram comparadas entre as curvas usando contrastes. A metodologia usada facilitou a interpretação das curvas e a detecção de diferenças na maturidade sexual, uniformidade e pico de produção. Esse trabalho valida o modelo de polinômios segmentados para uso em pesquisas futuras que tratem de análise de curvas de produção de ovos.

Data analysis and analytical predictions of a steam generator tube bundle flow field for verification of 2-D T/H computer code

International Nuclear Information System (INIS)

Hwang, J.Y.; Reid, H.C.; Berringer, R.

1981-01-01

Analytical predictions of the flow field within a 60 deg segment flow model of a proposed sodium heated steam generator are compared to experimental results obtained from several axial levels between baffling. The axial/crossflow field is developed by use of alternating multi-ported baffling, accomplished by radial perforation distribution. Radial and axial porous model predictions from an axisymmetric computational analysis compared to intra-pitch experimental data at the mid baffle span location for various levels. The analytical mechanics utilizes a cylindrical, axisymmetric, finite difference model, solving conservation mass and momentum equations. 6 refs

Monte Carlo analysis of thermal transpiration effects in capacitance diaphragm gauges with helicoidal baffle system

International Nuclear Information System (INIS)

Vargas, M; Stefanov, S; Wüest, M

2012-01-01

The Capacitance Diaphragm Gauge (CDG) is one of the most widely used vacuum gauges in low and middle vacuum ranges. This device consists basically of a very thin ceramic or metal diaphragm which forms one of the electrodes of a cap acitor. The pressure is determined by measuring the variation in the capacitance due to the deflection of the diaphragm caused by the pressure difference established across the membrane. In order to minimize zero drift, some CDGs are operated keeping the sensor at a higher temperature. This difference in the temperature between the sensor and the vacuum chamber makes the behaviour of the gauge non-linear due to thermal transpiration effects. This effect becomes more significant when we move from the transitional flow to the free molecular regime. Besides, CDGs may incorporate different baffle systems to avoid the condensation on the membrane or its contamination. In this work, the thermal transpiration effect on the behaviour of a rarefied gas and on the measurements in a CDG with a helicoidal baffle system is investigated by using the Direct Simulation Monte Carlo method (DSMC). The study covers the behaviour of the system under the whole range of rarefaction, from the continuum up to the free molecular limit and the results are compared with empirical results. Moreover, the influence of the boundary conditions on the thermal transpiration effects is investigated by using Maxwell boundary conditions.

Cultivation of Chlorella vulgaris in a pilot-scale sequential-baffled column photobioreactor for biomass and biodiesel production

International Nuclear Information System (INIS)

Lam, Man Kee; Lee, Keat Teong

2014-01-01

Highlights: • A new sequential baffled photobioreactor was developed to cultivate microalgae. • Organic fertilizer was used as the main nutrients source. • Negative energy balance was observed in producing microalgae biodiesel. - Abstract: Pilot-scale cultivation of Chlorella vulgaris in a 100 L sequential baffled photobioreactor was carried out in the present study. The highest biomass yield attained under indoor and outdoor environment was 0.52 g/L and 0.28 g/L, respectively. Although low microalgae biomass yield was attained under outdoor cultivation, however, the overall life cycle energy efficiency ratio was 3.3 times higher than the indoor cultivation. In addition, negative energy balance was observed in producing microalgae biodiesel under both indoor and outdoor cultivation. The minimum production cost of microalgae biodiesel was about RM 237/L (or USD 73.5/L), which was exceptionally high compared to the current petrol diesel price in Malaysia (RM 3.6/L or USD 1.1/L). On the other hand, the estimated production cost of dried microalgae biomass cultivated under outdoor environment was RM 46/kg (or USD 14.3/kg), which was lower than cultivation using chemical fertilizer (RM 111/kg or USD 34.4/kg) and current market price of Chlorella biomass (RM 145/kg or USD 45/kg)

Development and testing of 140 GHz absorber coatings for the water baffle of W7-X cryopumps

International Nuclear Information System (INIS)

Floristan, Miriam; Mueller, Philipp; Gebhardt, Andreas; Killinger, Andreas; Gadow, Rainer; Cardella, Antonio; Li, Chuanfei; Stadler, Reinhold; Zangl, Guenter; Hirsch, Matthias; Laqua, Heinrich P.; Kasparek, Walter

2011-01-01

Due to the relatively high strayfield radiation (140 GHz) from the electron cyclotron radio frequency heating system to which the W7-X cryopumps are expected to be subjected, coating systems acting as an efficient absorber for 140 GHz radiation have been developed for the water-cooled baffle shield in order to reduce the thermal load on the liquid N shield and the liquid He cryopanel. Several types of oxide ceramic coatings were applied on planar copper substrates by Atmospheric Plasma Spraying. The influence of the process parameters on the coating properties and microwave absorbing capability was analysed. It was found that film thickness and microstructure of the sprayed coatings have a significant influence on microwave absorption behaviour. For Al 2 O 3 /TiO 2 coatings, absorption values over 90% were obtained for the 140 GHz probing beam. After optimisation of the coating structure for maximum microwave absorption, the coating procedure was adapted by special robot trajectories to the complex water baffle geometry. The selected spray parameters and kinematics were then used for the complete coating of four mock-ups, which have been tested in the W7-X strayfield test facility Mistral. The mock-ups showed absorption values of 75%.

Development and testing of 140 GHz absorber coatings for the water baffle of W7-X cryopumps

Energy Technology Data Exchange (ETDEWEB)

Floristan, Miriam, E-mail: miriam.floristan@gsame.uni-stuttgart.de [Graduate School for advanced Manufacturing Engineering (GSaME), Universitaet Stuttgart (Germany); Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), Universitaet Stuttgart, Allmandring 7 b, D-70569 Stuttgart (Germany); Mueller, Philipp; Gebhardt, Andreas; Killinger, Andreas; Gadow, Rainer [Institute for Manufacturing Technologies of Ceramic Components and Composites (IMTCCC), Universitaet Stuttgart, Allmandring 7 b, D-70569 Stuttgart (Germany); Cardella, Antonio [European Commission c/o Wendelstein 7X, Boltzmannstasse 2, D-85748 Garching (Germany); Li, Chuanfei; Stadler, Reinhold; Zangl, Guenter; Hirsch, Matthias; Laqua, Heinrich P. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Assoc., Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Kasparek, Walter [Institut fuer Plasmaforschung, Universitaet Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany)

2011-10-15

Due to the relatively high strayfield radiation (140 GHz) from the electron cyclotron radio frequency heating system to which the W7-X cryopumps are expected to be subjected, coating systems acting as an efficient absorber for 140 GHz radiation have been developed for the water-cooled baffle shield in order to reduce the thermal load on the liquid N shield and the liquid He cryopanel. Several types of oxide ceramic coatings were applied on planar copper substrates by Atmospheric Plasma Spraying. The influence of the process parameters on the coating properties and microwave absorbing capability was analysed. It was found that film thickness and microstructure of the sprayed coatings have a significant influence on microwave absorption behaviour. For Al{sub 2}O{sub 3}/TiO{sub 2} coatings, absorption values over 90% were obtained for the 140 GHz probing beam. After optimisation of the coating structure for maximum microwave absorption, the coating procedure was adapted by special robot trajectories to the complex water baffle geometry. The selected spray parameters and kinematics were then used for the complete coating of four mock-ups, which have been tested in the W7-X strayfield test facility Mistral. The mock-ups showed absorption values of 75%.

3-D numerical study of the effect of Reynolds number and baffle angle on heat transfer and pressure drop of turbulent flow of air through rectangular duct of very small height

Directory of Open Access Journals (Sweden)

Abhijit Paul

2016-09-01

Full Text Available Present article illustrates a computational study of three-dimensional steady state heat transfer and high turbulent flow characteristics through a rectangular duct with constant heat fluxed upper wall and single rectangular cross-sectioned baffle insertion at different angles. RNG k–ɛ model along with standard wall function based computations has been accomplished applying the finite volume method, and SIMPLE algorithm has been executed for solving the governing equations. For a Reynolds number, Re of 10,000 to 50,000, Prandtl Number, Pr of 0.707 and baffle angle, α of 30°, 60°, 90°, 120°, 150°, computational studies are executed, centred onto the hydraulic diameter, Dh, test section and hydrodynamic entry length of the duct. Flow field has been solved using Ansys Fluent 14.0 software. Study exposes that baffled rectangular duct has a higher average Nusselt number, Nu and Darcy friction factor, f compared to a smooth rectangular duct. Nu as well as f are found to be maximum at 90° baffle angle. Results illustrate that both α and Re play a significant role in heat transfer as well as flow characteristics and also effects TEF. The correctness of the results attained in this study is corroborated by comparing the results with those existing in the literature for smooth rectangular duct within a precision of ±2% for f and ±4% for Nu.

Modelos socioeconómicos para las pymes

OpenAIRE

Viloria, Amelec

2007-01-01

En el presente artículo se revisan (5) modelos socioeconómicos para las Pequeñas y Medianas Empresas (PYMES): formación continua, asociatividad, desarrollo sostenible de empresas innovadoras, PYMES inteligentes y web fractal. Las ventajas y desventajas de dichos modelos se utilizaran para elaborar un nuevo modelo cuyo objetivo será incrementar la productividad de las PYMES del sector manufacturero en el estado Lara. Entre los aportes más importantes que los (5) modelos estudiados pueden hacer...

Modelos de engajamento

OpenAIRE

Santos,Roberval de Jesus Leone dos

2005-01-01

O artigo apresenta três modelos de engajamento propostos por autores fundamentais do século XX: Gramsci, Sartre e Camus. Após a revisão dos modelos, o autor desenvolve uma abordagem generalizada do fenômeno e apresenta duas conclusões principais: o engajamento tem de ser entendido em termos de grau; o engajamento é um fenômeno exclusivo de sociedades políticas ou antagônicas.The paper presents three models of engagement proposed by fundamental authors of the 20th century: Gramsci, Sartre and ...

Qualidade de vida de adolescentes modelos profissionais

Directory of Open Access Journals (Sweden)

Luciana Pires

Full Text Available Muitas adolescentes deixam suas famílias para seguir a profissão de modelo, sonhando com um futuro glamoroso. O presente estudo caso-controle analisou a qualidade de vida de 74 adolescentes do sexo feminino, sendo 37 modelos, agenciadas em São Paulo, com delineamento transversal, utilizando o World Health Organization Quality of Life - versão breve (WHOQOL-BREF, que avalia qualidade de vida global e os domínios físico, psicológico, social e ambiental. Utilizou-se o Critério Brasil 2008, para avaliação do nível socioeconômico e para parear o grupo controle. Em geral, o grupo de modelos obteve médias superiores ao grupo de não modelos, sendo esta diferença significante apenas no domínio psicológico. Observou-se que as adolescentes modelos apresentaram uma qualidade de vida semelhante à das não modelos.

Hacia un modelo de desempeño ocupacional : desarrollo del modelo = Towars a model of occupational performance: Model development

Directory of Open Access Journals (Sweden)

Chapparo , Christine

2008-02-01

Full Text Available RESUMEN:Este artículo ha esbozado el proceso de construcción del modelo que ha tenido como resultado un modelo de Desempeño Ocupacional. El estímulo para el desarrollo del modelo vino de la percepción de la necesidad de un modelo conceptual de la práctica de la terapia ocupacional y las ocupaciones humanas que fuera capaz de organizar el contenido de la terapia ocupacional dentro del currículo universitario en La Universidad de Sydney. El modelo actual incorpora ocho constructos fundamentales que incluyen: desempeño ocupacional, rol ocupacional, áreas ocupacionales, componentes del desempeño ocupacional, elementos centrales del desempeño ocupacional, ambiente, espacio y tiempo. Estos constructos emergieron a través de un proceso circular de teorización que incluía una revisión del material publicado, realización de pruebas sobre el terreno, reflexión y construcción del modelo. Este proceso circular continúa y la forma actual del modelo es considerada como una fase en la evolución de futuras nociones conceptuales del desempeño ocupacional.

Estudio del modelo de desgaste propuesto por Archard

Directory of Open Access Journals (Sweden)

FABIO ALEXANDER SUÁREZ BUSTAMANTE

2005-01-01

Full Text Available El comportamiento de componentes de máquinas y de materiales necesita ser optimizado para reducir los costos de operación en las plantas industriales. Este hecho ha impulsado la Tribología, un área relacionada con el estudio de la fricción, la lubricación y el desgaste. Uno de los principales objetivos de esta área del conocimiento es elaborar modelos matemáticos para expresar la variación del desgaste durante el contacto de superficies en movimiento, con el fin de predecir la vida útil de los elementos de máquinas. El modelo de Archard para desgaste por deslizamiento en seco, formulado en 1953, es un modelo clásico que plantea una variación del desgaste inversamente proporcional a la dureza del material y directamente proporcional a la carga aplicada. En el presente trabajo, se ha utilizado el método de modelamiento de problemas físicos, propuesto por Asbhy, para analizar los modelos propuestos por Archard (Modelo de contactos múltiples en superficies rugosas y modelo de desgaste mecánico. Con base en él se ha podido realizar un análisis profundo a dichos modelos, mostrando un panorama más amplio del modelo de Archard; se discuten aspectos no mostrados en los textos y artículos de tribología, donde el tratamiento dado a este modelo resulta ser superficial, desconociendo las limitaciones y la perspectiva que tuvo Archard sobre los aspectos que deberían considerarse en un modelo de desgaste.

La tutoría universitaria: del modelo actual a un modelo integral

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Manuel Álvarez González

2015-01-01

Full Text Available Este artículo señala la importancia de la acción tutorial en una educación universitaria de calidad y en un espacio de convergencia docente y tutorial, que tiene como objetivo primordial la formación integral del alumnado. Ahora bien, hemos de admitir que el modelo de tutoría actual ha mostrado una serie de déficits que no le han permitido cumplir con su cometido. Para ello, es necesario plantear una serie de aspectos de mejora que nos conduzcan a un modelo integral de tutoría donde han de tener cabida, de forma coordinada, los diferentes niveles o modalidades de tutoría, con la implicación, motivación y formación de todos los agentes educativos y de orientación de la institución. Y, para que este nuevo modelo tutorial pueda implantarse, requiere de un cambio en la función tutorial como un aspecto de la función docente y se han de facilitar las condiciones que permitan la consolidación de dicho modelo y esto no pude venir exclusivamente por la vía de una mera imposición (mandato legal, sino a través de un verdadero plan estratégico, que esté consensuado por todos.

Modal radiation patterns of baffled circular plates and membranes.

Science.gov (United States)

Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain; Jensen, Jørgen Arendt

2014-05-01

The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation force, which is used as a sound receiver in any medium or as a sound transmitter in a gaseous medium. A general, concise expression is given for the radiation pattern of any mode of the membrane and the plate with arbitrary boundary conditions. Specific solutions are given for the four special cases of a plate with clamped, simply supported, and free edge boundary conditions as well as for the membrane. For all non-axisymmetric modes, the velocity potential along the axis of the radiator is found to be strictly zero. In the long wavelength limit, the radiation pattern of all axisymmetric modes approaches that of a monopole, while the non-axisymmetric modes exhibit multipole behavior. Numerical results are also given, demonstrating the implications of having non-axisymmetric excitation using both a point excitation with varying eccentricity and a homogeneous excitation acting on half of the circular radiator.

Modelos de valoración basados en magnitudes contables: limitaciones del modelo de resultado residual Modelos de avaliação baseados na contabilidade: limitações do modelo do lucro residual

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Sonia Caro Fernández

2010-08-01

Full Text Available La investigación contable orientada al mercado de capitales ha vuelto a dirigir recientemente su interés hacia los modelos de valoración de acciones. Este cambio se ha venido produciendo de manera paralela a la constatación empírica de la existencia de numerosas anomalías en el comportamiento del mercado y la capacidad de las variables contables para explicar las diferencias en las rentabilidades obtenidas por los títulos en el mercado. Todo ello ha propiciado el diseño y desarrollo de estrategias de inversión que permitían obtener rentabilidades anormales positivas. En este escenario, el análisis de los datos contables ha ido cobrando mayor interés, centrándose el interés en tratar de determinar el valor de una empresa (valor intrínseco y, pasando a un segundo plano, la explicación del comportamiento del precio. La determinación del valor intrínseco pasa necesariamente por el establecimiento de un modelo de valoración. Durante la última década, el Modelo de Resultado Residual (MRR ha llegado a ser prominente en la literatura. El objetivo de este trabajo es analizar los fundamentos conceptuales del MRR. Después de indicar sus ventajas en comparación con los modelos tradicionales de valoración, nos centramos en la descripción de sus limitaciones tanto desde un punto de vista teórico como empírico. Las características más significativas que se analizan son: la violación de la "condición de excedente limpio", el efecto escala, y la estimación del valor terminal. Las distintas circunstancias inherentes a la aplicación empírica del modelo hacen que su análisis sea problemático, y que difícilmente podamos poner en duda su validez, ya que pueden ser las distintas proposiciones asumidas y necesarias para llevar el modelo a la práctica las que sean erróneas.A pesquisa contábil na área do mercado de capitais recentemente voltou a investigar os modelos de avaliação de ações. Esta mudança tem ocorrida de forma

Desde la coexistencia de modelos de representación, hasta la cristalización de un nuevo modelo: la ventana indiscreta

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Francisco Manuel Sánchez Sánchez

2014-12-01

Full Text Available Noël Burch puso las bases para la sistematización de los diferentes modelos de representación cinematográfica. El eje esencial de su argumentación, expuesto en El tragaluz del infinito, es que lo que distinguen los diferentes modelos es la posición de la mirada del espectador sobre la diégesis. Tomando en cuenta este punto de partida, Burch identifica dos modelos: el modelo de representación primitivo (MRP, regido por una mirada frontal y exterior al mundo diegético, y el modelo de representación institucional (MRI que se caracteriza por la ubicuidad de una mirada interior a ese mundo. Partiendo de esta consideración metodológica de estudio, el presente artículo rastrea la coexistencia de ambos modelos en La ventana indiscreta de Alfred Hitchcock,concretamente cómo se articulan y cohabitan en el texto fílmico, así como la cristalización de un modelo tercero caracterizado por una mirada independizada y vinculada a la cámara.

Influencia local em modelos de series temporais

OpenAIRE

Bruno Reis dos Santos

2008-01-01

Resumo: Nesta dissertação é discutido o uso da metodologia de diagnóstico de Influência Local em modelos de séries temporais. Especificamente, serão estudados os modelos autoregressivos de ordem um, os modelos de regressão com erros autoregressivos de ordem um e modelos de longa-memória. As medidas de influência local consideradas são: Inclinação de Billor e Loynes e Curvatura de Cook. As principais contribuições nesta dissertação são duas. Primeiro, a utilização da metodologia de limiares (b...

Modelo de contaminación del aire

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Iván Naula

2010-12-01

Full Text Available El presente documento estudia un modelo matemático de contaminación del aire, este modelo se basa en una ecuación en derivadas parciales de tipo parabólico lineal llamada ecuación de convección difusión. En la primera parte se trata el tema de contaminación del aire, su importancia, causas, consecuencias y por qué es necesario formular modelos matemáticos, luego se realiza un estudio de los principales resultados de la mecánica de medios continuos aplicados a la contaminación del aire, y se propone un modelo matemático.

Propuesta de un modelo genérico para el modelo de negocio

OpenAIRE

Daniele, Marcela; Baum, Gabriel Alfredo; Martellotto, Paola; Novaira, Maria Marta

2004-01-01

Para el abordaje al diseño y desarrollo de todo sistema de software es necesario estudiar en detalle la estructura y dinámica de la organización donde el mismo deberá funcionar. Esto ayudará a obtener una lista de requerimientos del sistema más acertada. Con el propósito enunciado, Booch, Rumbaugh y Jacobson [3] proponen construir el modelo de negocio como primera etapa del Proceso Unificado de desarrollo de software. En este trabajo analizamos los artefactos del modelo del negocio y sus rela...

Modelos matemáticos en un problema de epidemias

Directory of Open Access Journals (Sweden)

Anna Vidal

2016-01-01

Full Text Available La introducción de conceptos matemáticos a través del desarrollo y estudio de modelos ha sido tratado en numerosos trabajos. La introducción de los modelos suele hacerse básicamente desde el discurso del professor y el trabajo del alumno suele reducirse a la experimentación con el modelo dado. La aproximación a un problema mediante modelos IBM (Individual Based Model resulta más comprensible para el alumno, permite justificar y complementar otras aproximaciones a la solución (modelos diferenciales continuos y/o modelos discretos. En este trabajo se presenta una experiencia docente basada en afrontar un mismo problema mediante enfoques complementarios en base a modelos continuos, discretos e IBM. Finalmente se presenta una propuesta metodológica para ponerla en práctica utilizando el Aprendizaje Cooperativo y el Problem/Project Based Learning.

Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

Science.gov (United States)

Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

2015-01-01

In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

Evaluación de un modelo de la brdf a partir de simulaciones con modelos semi-empíricos lineales (sel

Directory of Open Access Journals (Sweden)

Edgardo Rafael Medrano Ruedaflores

2013-07-01

Full Text Available Los modelos semi-empíricos lineales, también conocidos como modelos lineales basados en kernels, han sido utilizados con relativo éxito en la derivación de parámetros biofísicos de la vegetación a partir de imágenes satelitales. Su construcción se basa en hipótesis difíciles de corroborar y su calibración demanda suponer condiciones de homogeneidad en el sistema suelo-vegetación-atmósfera. Un modelo de la BRDF libre de estas limitaciones es evaluado en este estudio simulando el proceso de dispersión de la radiación solar según diferentes configuraciones de cobertura terrestre. Los datos fueron generados mediante la implementación de cuatro modelos lineales basados en kernels. Se evaluó el ajuste del modelo en cada escenario simulado a través de regresión lineal simple, obteniéndose valores del coeficiente de determinación superiores a 0.98. Los resultados sugieren que es posible utilizar el modelo evaluado en aplicaciones donde actualmente se emplean modelos semi-empíricos lineales.

Heat Flow Characteristics of a Newly-Designed Cooling System with Multi-Fans and Thermal Baffle in the Wheel Loader

Directory of Open Access Journals (Sweden)

Yidai Liao

2017-03-01

Full Text Available In the traditional cooling case, there is usually one fan in charge of heat transfer and airflow for all radiators. However, this seems to be inappropriate, or even insufficient, for modern construction machinery, as its overall heat flow density is increasing but thermal distribution is becoming uneven. In order to ensure that the machine works in a better condition, this paper employs a new cooling system with multiple fans and an independent cooling region. Based on the thermal flow and performance requirements, seven fans are divided into three groups. The independent cooling region is segregated from the engine region by a thermal baffle to avoid heat flowing into the engine region and inducing an overheat phenomenon. The experiment validates the efficiency of the new cooling system and accuracy of simulation. After validation, the simulation then analyzes heat transfer and flow characteristics of the cooling system, changing with different cross-sections in different axis directions, as well as different distances of the fan central axes. Finally, thermal baffles are set among the fan groups and provided a better cooling effect. The research realizes a multi-fan scheme with an independent cooling region in a wheel loader, which is a new, but high-efficiency, cooling system and will lead to a new change of various configurations and project designs in future construction machinery.

Un procedimiento para selección de los modelos Logit Mixtos

OpenAIRE

Ruíz Gallegos, José de Jesús

2004-01-01

En el presente trabajo se hace una revisión de dos modelos que han tenido una fuerte aplicabilidad en los problemas de elecciones discretas: El modelo Logit y el modelo Logit Mixto. Además, se propone el uso del estadístico de Cox para seleccionar modelos, en el modelo Logit Mixto.

Modelo hipermedia creador (HC

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Manuel Armenteros Gallardo

2012-04-01

Full Text Available El presente artículo expone las bases creativas del modelo Hipermedia Creador (HC, un modelo basado en la filosofía de los llamados tutores inteligentes. Tiene como objetivo la creación de una herramienta hipermedia que permita y facilite la producción creativa de proyectos hipermedias educativos con parámetros comunes a los usados en la fórmula del videojuego (entretenimiento. Se describe su estructura, y se analiza y explica la disposición creativa de sus elementos, entre los cuales sobresale las posibilidades pedagógicas del movimiento expresivo de la imagen.

Las Maquiladoras Fronterizas, (Modelo Agotado?)

OpenAIRE

Carrillo, Jorge

2008-01-01

Los esfuerzos por parte de paises en desarrollo para actualizar su capacidad industrial ha llevado a Ia reorganizacion de sus sectores manufactureros. En Mexico Ia viabilidad de este modelo ha sido cuestionada debido al declive de Ia industria maquiladora a lo largo de Ia frontera. Dos razones que explican el declive son frecuentemente discutidas: primero, el aumento de Ia competitividad de paises como China, y segundo, los limites estructurales del modelo de industrializacion basado en expor...

El dinero en los modelos macroeconómicos

OpenAIRE

Wilfredo Toledo

2006-01-01

Un reto de la economía monetaria es el desarrollo de una teoría endógena del dinero; un modelo en el que el dinero surja de manera natural y no como una imposición externa. Este trabajo discute los principales enfoques de la economía monetaria, y argumenta que los modelos de generaciones traslapadas y los modelos de búsqueda son las mejores alternativas

El dinero en los modelos macroeconómicos

Directory of Open Access Journals (Sweden)

Toledo , Wilfredo

2006-12-01

Full Text Available Un reto de la economía monetaria es el desarrollo de una teoría endógena del dinero; un modelo en el que el dinero surja de manera natural y no como una imposición externa. Este trabajo discute los principales enfoques de la economía monetaria, y argumenta que los modelos de generaciones traslapadas y los modelos de búsqueda son las mejores alternativas

Performance study of solar air heater duct having absorber plate with V down perforated baffles

Directory of Open Access Journals (Sweden)

Sunil Chamoli

2014-04-01

Full Text Available This paper presents results of a study of the performance of solar air heaters with V down perforated baffles as roughness on the air flow side of the absorber plate. Investigations have been carried out using a mathematical model to study the effects of ambient conditions, operating and design parameters on effective efficiency of such air heaters. The thermal and effective efficiencies differ only marginally at lower flow rates. With an increase in the flow rate, the difference between the thermal and effective efficiencies increases because of the increase in the pumping power. The results of the study are presented in the form of plots to show the effect of ambient, design and operating conditions on thermal and effective efficiency.

Modelo de contaminación del aire

OpenAIRE

Iván Naula

2010-01-01

El presente documento estudia un modelo matemático de contaminación del aire, este modelo se basa en una ecuación en derivadas parciales de tipo parabólico lineal llamada ecuación de convección difusión. En la primera parte se trata el tema de contaminación del aire, su importancia, causas, consecuencias y por qué es necesario formular modelos matemáticos, luego se realiza un estudio de los principales resultados de la mecánica de medios continuos aplicados a la contaminación del aire, y se p...

Questionando empiricamente a validade do modelo fleuriet

OpenAIRE

Medeiros, Otávio Ribeiro de; Rodrigues, Fernanda Fernandes

2004-01-01

O estudo relata o resultado de testes empíricos sobre a validade do modelo Fleuriet, também conhecido como Análise Avançada ou Dinâmica do Capital de Giro. Segundo alguns autores, o modelo, introduzido no Brasil nos anos 1980, trouxe importantes inovações para a análise do capital de giro. Uma hipótese fundamental do modelo é que ativos e passivos circulantes financeiros são variáveis erráticas, não relacionadas às operações das empresas, ao contrário dos ativos e passivos circ...

Identificación Robusta de Modelos Wiener y Hammerstein

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Silvina I. Biagiola

2009-04-01

Full Text Available Resumen: Los modelos orientados a bloques han mostrado ser útiles y eficaces como representaciones no lineales en muchas aplicaciones. Son modelos simples y a la vez válidos en una región más amplia que un modelo lineal invariante en el tiempo. En cuanto a su estructura, consisten en una cascada integrada por una dinámica lineal y un bloque estático no lineal.Si bien existen en la literatura numerosos trabajos que abordan la identificación nominal de estos modelos, el problema de identificación robusta en presencia de incertidumbre no ha sido cabalmente tratado.En este trabajo, se consideran dos clases de modelos orientados a bloques: modelos Wiener y Hammerstein. Empleando una representación paramétrica, se propone describir la incertidumbre como un conjunto de parámetros, cuyos valores se obtienen resolviendo un problema de optimización. El algoritmo de identificación desarrollado se ilustra mediante ejemplos de simulación. Palabras clave: Wiener, Hammerstein, Identificación, Incertidumbre, Optimización

Modelos de engajamento

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Roberval de Jesus Leone dos Santos

2005-08-01

Full Text Available O artigo apresenta três modelos de engajamento propostos por autores fundamentais do século XX: Gramsci, Sartre e Camus. Após a revisão dos modelos, o autor desenvolve uma abordagem generalizada do fenômeno e apresenta duas conclusões principais: o engajamento tem de ser entendido em termos de grau; o engajamento é um fenômeno exclusivo de sociedades políticas ou antagônicas.The paper presents three models of engagement proposed by fundamental authors of the 20th century: Gramsci, Sartre and Camus. After the revision of the models, the author develops a generalized approach of the phenomenon and it presents two main conclusions: the engagement must be understood within limits of degree; the engagement is a phenomenon exclusive of political or antagonistic societies.

Armonización de modelos de calidad del software

Directory of Open Access Journals (Sweden)

Gabriel Alberto Garcia Mireles

2013-06-01

Full Text Available La tendencia actual entre las organizaciones que desarrollan software es la adopción de más de un modelo de calidad para estar en condiciones de competir en diversos sectores del mercado. En esa situación, las organizaciones se enfrentan al problema de coordinar la implantación de múltiples modelos de tal manera que cada modelo logre los beneficios esperados, y al mismo tiempo, que los costos y esfuerzo de implantación sean mínimos. Como respuesta a este problema, surge la armonización de modelos de calidad del software. Actualmente los estudios se centran en la composición de modelos de calidad que abordan prácticas del proceso de desarrollo de software. Sin embargo, las organizaciones también deberían considerar la perspectiva de la calidad del producto. En este artículo, se presenta un avance de la investigación en la armonización de modelos de calidad que toma en cuenta ambas perspectivas, proceso y producto. Se describe la técnica que se propuso para realizar comparaciones de bajo nivel en este contexto. La técnica se aplica en los modelos CMMI-DEV, ISO 12207 e ISO 25010 y, como resultado, se encuentra que los modelos que abordan la perspectiva de proceso contienen prácticas, que corresponden a las etapas de análisis y diseño de software, en donde se debería prestar más atención a la calidad del producto de software.

Un modelo SETAR para el PIB colombiano

Directory of Open Access Journals (Sweden)

Vivas Lorena

2010-08-01

Full Text Available En este artículo se estudia el comportamiento de la tasa de crecimiento del PIB colombiano entre 1982-2008 a partir de un modelo SETAR (Self-Exciting Threshold Autoregressive, empleando la metodología propuesta por Tsay (1989 y Tong (1990 para la detección de no linealidades relacionadas con la existencia de regímenes cambiantes. Adicionalmente, se comparan los pronósticos generados con los obtenidos en un modelo autorregresivo lineal para diferentes horizontes de predicción, empleando funciones de pérdida simétricas. Los resultados muestran evidencia empírica de que existe no linealidad de umbral en la serie asociada a las altas o bajas tasas de crecimiento registradas por su rezago anual (permaneciendo más tiempo en el régimen de tasas de crecimiento más elevadas y que el desempeño de los pronósticos del modelo SETAR parece no mejorar con respecto al modelo base.

MODELOS HETERODOXOS DE CRESCIMENTO EM ECONOMIAS ABERTAS: UMA EXTENSÃO DOS MODELOS DE KALDOR-THIRLWALL

Directory of Open Access Journals (Sweden)

André Luís Cabral de Lourenço

2015-12-01

Full Text Available RESUMO O artigo teve por objetivo central contribuir para o processo de construção de modelos de crescimento heterodoxos para economias abertas na linha de Kaldor (1970 e Thirlwall (1979. Para tanto: i recuperou os elementos comuns a esses modelos que forneceram uma base teórica geral para a construção de modelos; ii buscou melhorar a articulação entre as taxas de crescimento da demanda agregada e a taxa de crescimento permitida pela restrição externa, bem como preencher o vácuo decorrente da ausência do crescimento da demanda agregada; iii resenhou a literatura que visa melhorar a modelagem da restrição externa nessa linha teórica, recolhendo importantes inspirações para construir uma forma de modelar a restrição externa que evitasse algumas das deficiências presentes na literatura; iv explorou algumas das propriedades e aspectos mais salientes da solução assim gerada.

El modelo neurobiológico de la conciencia

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Luis Álvarez Munárriz

2014-01-01

Full Text Available El modelo neurobiológico de la conciencia está implantado y arraigado en la ciencia actual. En esta contribución se pretende probar que posee unos débiles cimientos que deben ser reforzados. Para mostrarlo se reflexiona críticamente sobre tres de sus dimensiones que se pueden considerar esenciales: (i la identificación de conciencia y cerebro; (ii la negación del libre albedrío; y (iii las escasas aplicaciones clínicas del modelo. Estas reflexiones nos indican la necesidad de construir un modelo más robusto. Se necesita un modelo predictivo cuyos resultados no solamente se puedan validar sino que además tengan aplicaciones prácticas que sirvan para mejorar el bienestar y la calidad de vida de las personas.

Modelo de Cuidado: ¿Qué es y como elaborarlo?

Directory of Open Access Journals (Sweden)

Patricia Kuerten Rocha

Full Text Available En el presente artículo se realiza una reflexión teórica sobre el significado del modelo de cuidado de enfermería, además de ofrecer elementos para su elaboración. Existe una diversidad de terminologías sobre lo que es modelo de cuidado y sus elementos, tales como: modelo de cuidado, marco/sistema/modelo conceptual, marco de referencia, marco teórico, metodología y método. En este estudio son presentadas las etapas que sistematizan el desarrollo de un modelo de cuidado, a saber: planeamiento, desarrollo, implementación y evaluación. Por ser dinámica, la elaboración de un modelo de cuidado necesita de la interacción directa entre el investigador y el sujeto. La lógica inductiva-deductiva-inductiva le permite al investigador un ir y venir del mundo de la práctica al mundo abstracto reflexivo. Un modelo de cuidado nos remite a la construcción de un conocimiento que favorece un cuidar diferenciado y específico, al mismo tiempo que estimula el conocimiento y el desarrollo de la Enfermería. De esa manera, los modelos de cuidado engloban un conjunto de conocimientos que califican y perfeccionan la praxis de la Enfermería.

Effect of Six Missile-Bay Baffle Configurations and a Rocket End Plate on Ejection Releases of an MB-1 Rocket from a 0.05 Scale Model of the Convair F-106A Airplane

Science.gov (United States)

Hinson, William F.; Lee, John B.

1959-01-01

As a continuation of an investigation of the release characteristics of an MB-1 rocket carried internally by the Convair F-106A airplane, six missile-bay baffle configurations and a rocket end plate have been investigated in the 27- by 27-inch preflight jet of the NASA Wallops Station. The MB-1 rocket used had retractable fins and was ejected from a missile bay modified by the addition of six different baffle configurations. For some tests a rocket end plate was added to the model. Dynamically scaled models (0.04956 scale) were tested at a simulated altitude of 22,450 feet and Mach numbers of 0.86, 1.59, and 1.98, and at a simulated altitude of 29,450 feet and a Mach number of 1.98. The results of this investigation indicate that the missile-bay baffle configurations and the rocket end plate may be used to reduce the positive pitch amplitude of the MB-1 rocket after release. The initial negative pitching velocity applied to the MB-1 rocket might then be reduced in order to maintain a near-level-flight attitude after release. As the fuselage angle of attack is increased, the negative pitch amplitude of the rocket is decreased.

Modelo Concesionado de Prisiones Federales en México

OpenAIRE

Gutiérrez Rosales, Francisco

2016-01-01

El presente proyecto de investigación aplicada se elaboró con la finalidad de comparar el modelo concesionado de prisiones federales en México con el modelo público de prisiones. El objetivo general fue analizar el modelo concesionado de prisiones federales, en términos de reinserción social, capacidad y población reclusa, para emitir recomendaciones de Política Pública. La finalidad de los objetivos específicos; conocer la situación actual del sistema penitenciario mexicano e identificar...

Modelo experimental de un motor unipolar

Directory of Open Access Journals (Sweden)

Luz Karine Sandoval

2010-01-01

Full Text Available Se describe la caracterización experimental de un prototipo de motor unipolar con el objeto de validar su modelo matemático. Este tipo de motor es bastante controversial a la hora de pretender explicar su modelo y fundamento de operación. Ha existido por cerca de casi dos siglos y aún persiste su misteriosa forma de funcionamiento; parece eludir cualquier explicación convencional a la luz de las ecuaciones de Maxwell. Es un dispositivo que genera una fuerza electromotriz (fem, aunque el flujo magnético que atraviesa el circuito no varía con el tiempo. El prototipo construido mostró la validez del modelo, esto es, una resistencia eléctrica y una fuente de tensión, puesto que al medir la velocidad angular alcanzada durante un intervalo de tiempo, se observó su crecimiento exponencial. La función de transferencia del motor es de primer orden, justo como se esperaba, dado que carece de elementos como bobinas o capacitores; sin embargo, tarda de treinta a cuarenta segundos en alcanzar su estado estable. Esto se debe, según el modelo planteado, a la resistencia eléctrica interna de este dispositivo.

Modelos matemáticos a partir del modelo nomológico–deductivo de la explicación científica

OpenAIRE

Caraballo, Horacio A.; González, Cecilia Z.

2008-01-01

Mostraremos a continuación la posibilidad de generar modelos matemáticos simples a partir de la explicación de un hecho físico. El marco teórico de partida es el de la explicación científica con la estructura del modelo nomológico deductivo. El uso de modelos matemáticos en este marco genera herramientas didácticas de distinto tipo, en este articulo desarrollamos brevemente el diseño de proyectos de investigación para los alumnos. El docente puede generar y luego utilizar estos proyectos de d...

Modelo de gerencia del conocimiento: visión integral

Directory of Open Access Journals (Sweden)

César A. Bernal Torres

2011-12-01

Full Text Available Este artículo tiene como propósito el diseño de un modelo integral de la gerencia o administración del conocimiento como recurso estratégico para potenciar la capacidad competitiva de las organizaciones. El objetivo del modelo es contribuir a dar respuesta a dos inquietudes básicas de muchos directivos empresariales y estudiosos del á tema en el entorno de los países en desarrollo: a la necesidad de modelos gerenciales propios y pertinentes a la realidad de las organizaciones y b la integración de la diversidad de modelos dispersos existentes sobre este campo para facilitar su comprensión y aplicación. La construcción del modelo se realizó a partir de una amplia revisión bibliográfica sobre el tema, un trabajo de campo en el contexto de referencia con entrevistas a directivos empresariales y un análisis de expertos

IDENTIFICACIÓN DE MODELOS ARFIMA

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Elkin Castaño-Vëlez

2016-01-01

Full Text Available Desde la introducción de los modelos fraccionalmente integrados ARFIMA para  series de tiempo con memoria larga, ha surgido un gran interés en el estudio de sus propiedades y áreas de aplicación. En este modelo, el grado de la memoria está definido por el parámetro de diferenciación fraccional, el cual toma valores en un intervalo continuo de números reales. Para realizar la estimación de este parámetro y probar la existencia de memoria larga, se han propuesto distintos procedimientos en la literatura. Ahora bien, generalmente no basta con conocer si hay memoria larga en la serie de tiempo, sino que es necesario estimar adecuadamente el valor del parámetro de diferenciación fraccional, del cual depende la dinámica de largo plazo de la serie, y de la componente ARMA asociada al comportamiento de corto plazo. Esta estimación requiere de la especificación correcta del modelo ARFIMA.  El objeto de este documento es el de implementar un proceso de identificación del modelo ARFIMA para series estacionarias a partir de un procedimiento paramétrico propuesto, y comparar su desempeño con métodos semiparamétricos propuestos en la literatura.  Los resultados obtenidos a través de un estudio de simulación, muestran que el procedimiento propuesto tiene, en general, un mejor desempeño.

Development of a compact W-shaped pumped divertor in JT-60U

Energy Technology Data Exchange (ETDEWEB)

Sakurai, S.; Hosogane, N.; Masaki, K.; Kodama, K.; Sasajima, T.; Kishiya, K.; Takahashi, S.; Shimizu, K.; Akino, N.; Miyo, Y.; Hiratsuka, H.; Saidoh, M. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Inoue, M.; Umakoshi, T.; Onozuka, M.; Morimoto, M. [Mitsubishi Heavy Industries, Wadasaki-cho, Hyogo-ku, Kobe-shi, 642 (Japan)

1998-09-01

In JT-60U, the modification to a W-shaped pumped divertor will be completed in May 1997, aiming to realize sufficient reduction in heat flux to the targets and good H-mode confinement simultaneously. W-shaped geometry is optimized not only for forming radiative divertor plasmas and reducing the back flow of neutral particles but also for allowing various experimental configurations. Toroidally and poloidally segmented divertor plates, dome and baffles are arranged in a W-shaped poloidal configuration. The pumping speed can be changed during a shot by variable shutter valves in the three pumping ports under the outer baffle. The net throughput is enough for particle control in the steady radiative operations with high power NBI heating. Carbon fiber composite (CFC) tiles are used for the divertor targets and the divertor throat where large heat flux is expected. Gaps between two adjacent segments are carefully sealed to suppress the leak of neutral gas from the exhaust duct below the divertor and baffles. The strength of the whole structure is confirmed by an electromagnetic force analysis and structural analysis carried out for disruptions of 3 MA discharges with a halo current. (orig.) 11 refs.

Vortex Shedding Inside a Baffled Air Duct

Science.gov (United States)

Davis, Philip; Kenny, R. Jeremy

2010-01-01

Common in the operation of both segmented and un-segmented large solid rocket motors is the occurrence of vortex shedding within the motor chamber. A portion of the energy within a shed vortex is converted to acoustic energy, potentially driving the longitudinal acoustic modes of the motor in a quasi-discrete fashion. This vortex shedding-acoustic mode excitation event occurs for every Reusable Solid Rocket Motor (RSRM) operation, giving rise to subsequent axial thrust oscillations. In order to better understand this vortex shedding/acoustic mode excitation phenomena, unsteady CFD simulations were run for both a test geometry and the full scale RSRM geometry. This paper covers the results from the subscale geometry runs, which were based on work focusing on the RSRM hydrodynamics. Unsteady CFD simulation parameters, including boundary conditions and post-processing returns, are reviewed. The results were further post-processed to identify active acoustic modes and vortex shedding characteristics. Probable locations for acoustic energy generation, and subsequent acoustic mode excitation, are discussed.

Modelos de gestión de resultados: un estudio transnacional

Directory of Open Access Journals (Sweden)

Nuria Reguera Alvarado

2015-01-01

Así pues, a partir de los modelos desarrollados en la literatura para cuantificar la discrecionalidad contable, el objetivo de este trabajo es determinar si alguno de estos modelos ofrece mejores resultados en cuanto a la cuantificación de la gestión del resultado a partir de las pruebas de especificación y potencia. Para ello se ha utilizado una muestra de 33.410 observaciones correspondientes a empresas no financieras de Estados Unidos, Canadá, Reino Unido, Corea, Japón, Italia, Alemania, Francia, España, Canadá y Australia que han cotizado en mercados de valores a lo largo del periodo 2005-2009. Los resultados ponen de manifiesto la superioridad del modelo de Jones ajustado al ROA con respecto al modelo de Jones y al modelo de Jones modificado.

Segmentation: Identification of consumer segments

DEFF Research Database (Denmark)

Høg, Esben

2005-01-01

It is very common to categorise people, especially in the advertising business. Also traditional marketing theory has taken in consumer segments as a favorite topic. Segmentation is closely related to the broader concept of classification. From a historical point of view, classification has its...... origin in other sciences as for example biology, anthropology etc. From an economic point of view, it is called segmentation when specific scientific techniques are used to classify consumers to different characteristic groupings. What is the purpose of segmentation? For example, to be able to obtain...... a basic understanding of grouping people. Advertising agencies may use segmentation totarget advertisements, while food companies may usesegmentation to develop products to various groups of consumers. MAPP has for example investigated the positioning of fish in relation to other food products...

Pretreatment of textile dyeing wastewater using an anoxic baffled reactor.

Science.gov (United States)

Kong, Huoliang; Wu, Huifang

2008-11-01

A study on pretreatment of textile dyeing wastewater was carried out using an anoxic baffled reactor (ABR) at wastewater temperatures of 5-31.1 degrees C. When hydraulic retention time (HRT) was 8h, the color of outflow of ABR was only 40 times at 5 degrees C and it could satisfy the professional discharge standard (grade-1) of textile and dyeing industry of China (GB4287-92). The total COD removal efficiency of ABR was 34.6%, 47.5%, 50.0%, 53.3%, 54.7% and 58.1% at 5, 9.7, 14.9, 19.7, 23.5 and 31.1 degrees C, respectively. Besides, after the wastewater being pre-treated by ABR when HRT was 6h and 8h, the BOD5/COD value rose from 0.30 of inflow to 0.46 of outflow and from 0.30 of inflow to 0.40 of outflow, respectively. Experimental results indicated that ABR was a very feasible process to decolorize and pre-treat the textile dyeing wastewater at ambient temperature. Moreover, a kinetic simulation of organic matter degradation in ABR at six different wastewater temperatures was carried through. The kinetic analysis showed the organic matter degradation was a first-order reaction. The reaction activation energy was 19.593 kJ mol(-1) and the temperature coefficient at 5-31.1 degrees C was 1.028.

Metallurgical examinations update of baffle bolts removed from operating French PWR. Microstructural investigations of a baffle to former bolt located on a high level of the internal structures

International Nuclear Information System (INIS)

Panait, C.; Fargeas, E.; Miloudi, S.; Moulart, P.; Tommy-Martin, M.; Monteil, N.; Pokor, C.

2015-01-01

This paper presents the microstructural investigations conducted on a cracked baffle to former bolt extracted from an upper former level of the internal structures of a French Pressurized Water Reactor (PWR). Extensive microstructural investigations using Light Microscopy, Scanning Electron Microscopy and Transmission Electron Microscopy (TEM) have been conducted to understand the degradation mechanisms of this bolt. TEM investigations have revealed neutron irradiation damage in the microstructure of the bolt such as Frank loops and cavities and/or bubbles. The number of features per unit volume as a function of diameter was determined in the head and in the shank of the bolt. The obtained results are relatively similar to those obtained for other damaged bolts extracted from PWR-type reactors and irradiated in similar conditions (dose and temperature). The irradiation damage has induced an evolution of the mechanical properties (hardening of the material), as revealed by the hardness measurements along the bolt, with a higher average value in the head (400 HV), compared to the shank (15 mm under the head), about 340 HV. The metallurgical investigations have confirmed that this bolt was damaged by Irradiation Assisted Stress Corrosion Cracking (IASCC)

Modelo ENCUIST: aplicación al perfilado criminal

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Lucía Halty

2017-01-01

Full Text Available El presente trabajo se encuentra dentro del marco de la Psicología Jurídica. Dentro de este ámbito uno de los aspectos que más interés suscita son los perfiles criminales. Se propone el modelo ENCUIST como modelo de personalidad para la realización del perfil indirecto de la personalidad, con la inclusión de las variables de extroversión/búsqueda de sensaciones, neuroticismo (ansiedad, ira y asco, insensibilidad emocional, impulsividad/agresividad y necesidad de cognición. Mediante la aplicación de modelos de ecuaciones estructurales se analiza tanto la influencia directa como indirecta de dichas variables en el modelo de Gray (BIS/BAS. La muestra está formada por 737 sujetos a los que se aplica el test de personalidad ENCUIST para evaluar los rasgos mencionados. Los resultados de la investigación se discuten a continuación.

Una taxonomía de modelos de desarrollo sustentable

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Darcy Tetreault

2004-01-01

Full Text Available Este ensayo pretende ayudar a desenmarañar una parte del discurso sobre desarrollo sustentable mediante la construcción de una taxonomía de modelos de desarrollo sustentable. La misma taxonomía se basa en una revisión literaria extensiva que en cierta medida privilegia la experiencia mexicana. De este modo, el ensayo presenta y compara tanto modelos normativos como positivos. Los modelos incluidos son el modelo dominante, el cual corresponde con la estrategia esbozada en el Informe Bruntland y Agenda 21; la ecología política, un modelo desarrollado por el economista francés Alain Lipietz; el modelo comunitario de desarrollo sustentable, cuyas raíces se encuentran en una escuela de pensamiento de la década de los setenta conocida como el “otro desarrollo”; el comercio justo, una experiencia cuyas raíces se encuentran en las comunidades indígenas de Oaxaca; la producción forestal industrial comunitaria, que ha sido puesta en práctica por varias comunidades forestales en el sur y el centro del país; el activismo ambiental, sobre todo respecto a los con- fl ictos locales que giran en torno al control de los recursos naturales; y la conservación basada en la comunidad, cuya manifestación principal es la reserva de la biosfera

Calculo y comparacion de la prima de un reaseguro de salud usando el modelo de opciones de Black-Scholes y el modelo actuarial

Directory of Open Access Journals (Sweden)

Luis Eduardo Giron

2015-12-01

Full Text Available La presente investigación pretende calcular y comparar la prima de un reaseguro  usando el modelo de opciones de Black-Scholes y el modelo clásico actuarial tradicional. El período de análisis va desde enero de 2011 hasta diciembre de 2012. Los resultados obtenidos muestran que el modelo de Black-Scholes, que se utiliza normalmente para valorar opciones financieras, puede ser también usado para la estimación de primas de reaseguros de salud; y que la prima neta estimada a partir de este modelo se aproxima a las establecidas por el método actuarial, excepto cuando el deducible del reaseguro es muy alto (por encima de $200.000.000.

Application of beryllium as first wall armour for ITER primary, baffle and limiter modules

International Nuclear Information System (INIS)

Cardella, A.; Barabash, V.; Ioki, K.; Yamada, M.; Mazul, I.; Merola, M.; Strebkov, Y.

2000-01-01

During the engineering design activities of the ITER project, beryllium has been selected as the armour material for the first wall of the primary, baffle and limiter blanket modules. These components have different requirements according to their function, so the armour design and its joining technology has been developed in order to withstand different operating and loading conditions. Extensive R and D has been performed to develop, select and characterise the beryllium material and the joining techniques. In parallel, beryllium plasma spray coating has been developed, mainly as a possible in situ repair method for locally damaged areas. For the reduced technical objectives / reduced cost (RTO/RC) ITER project, it is proposed to maintain Be as the reference armour material and to optimise the manufacturing technologies in order to minimise costs. The paper presents the rationale of the design choices for the application of beryllium to the blanket first wall and gives an overview of the R and D performed and the results achieved. (orig.)

Modelos clínico e psicossocial de atenção ao indivíduo e à família na assistência domiciliar: bases conceituais Modelos clínico y psicosocial de atención al individuo y la familia en la asistencia domiciliaria: bases conceptuales Clinical and psychosocial models of attention to the individual and the family in home care: conceptual frameworks

Directory of Open Access Journals (Sweden)

Vilanice Alves de Araújo Püschel

2006-06-01

Full Text Available Prestar assistência no domicílio tem sido uma prática em expansão no Brasil. No entanto, o modelo de assistência tem se baseado no modelo clínico e hospitalar. Este artigo tem como objetivo propor referenciais teóricos para um modelo de atenção voltado à assistência domiciliar, considerando a dimensão psicossocial. São apresentadas, didaticamente separadas, as bases conceituais dos modelos clínico e psicossocial, apesar de serem indissociáveis, de modo a contribuir para o aprimoramento de uma prática que seja capaz de agregar expressões da pessoa e do contexto enquanto elementos de uma dinâmica psicossocial.Prestar asistencia en el domicilio ha sido una práctica en expansión en el Brasil. No obstante, el modelo de asistencia se ha basado en el modelo clínico y hospitalario. Este artículo tiene como objetivo proponer referenciales teóricos para un modelo de atención volcada a la asistencia domiciliaria, considerando la dimensión psicosocial. Se presentan las bases conceptuales del modelo clínico y psicosocial, didácticamente separados, a pesar de no ser disociables, como una contribución al perfeccionamiento de una práctica capaz de agregar expresiones de la persona y del contexto en cuanto elemento de una dinámica psicosocial.Home care is a rapidly expanding segment in Brazil. The model currently applied to home care is based on clinical and hospital models. The objective of this article is to propose theoretical frameworks that can be applied to home care by taking into account its psychosocial dimension. Although indivisible, the conceptual frameworks of the clinical and the psychosocial models are broken down, for clarity purposes, in order to contribute to the improvement of practices, so as to add personal expressions and contexts as elements of psychosocial dynamics.

Intergranular cracking mechanism in baffle former bolt materials for PWR core internals

Energy Technology Data Exchange (ETDEWEB)

Yonezawa, Toshio; Arioka, Koji; Kanasaki, Hiroshi; Fujimoto, Koji [Takasago R and D Center, Mitsubishi Heavy Industries Ltd., Takasago, Hyogo (Japan); Ajiki, Kazuhide [Kobe Shipyard and Machinery, Mitsubishi Heavy Industries Ltd., Kobe, Hyogo (Japan); Matsuoka, Takanori [Nuclear Development Corp., Tokai, Ibaraki (Japan); Urata, Sigeru; Mizuta, Hitoshi [Kansai Electric Power Co., Inc., Osaka (Japan)

2000-03-01

In this study, the cause of intergranular cracking in baffle former bolts(BFBs) was estimated from metallurgical and chemical viewpoints based upon the experimental data and information published by EdF. At first, five kinds of possibilities were estimated as the cause of intergranular cracking in BFBs. Five possibilities estimated were (1) mechanical cracking caused by high strain in irradiation hardened austenitic stainless steels, (2) O{sub 2} SCC due to residual oxygen in the bolt stagnant region, (3) caustic SCC due to dry and wet phenomenon, (4) low pH SCC due to oxygen concentration cell, and (5) PWSCC due to radiation induced segregation. In this study each possibility was evaluated by the calculation and some out of pile tests. And also, the cause of the intergranular cracking in BFBs was estimated by the data of the post-irradiation examinations and basic out of pile tests for Type 316CW and Type 347 stainless steels in the authors' previous study. From these evaluation, the intergranular cracking in BFBs seems to be caused by the PWSCC, but not caused by mechanical cracking O{sub 2} SCC, caustic SCC or low pH SCC. (author)

Terapia cognitivo-comportamental da fobia social: modelos e técnicas

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Gustavo J. Fonseca D'El Rey

2006-08-01

Full Text Available A fobia social é um dos transtornos mentais mais prevalentes na população geral. As principais formas de tratamento são a psicoterapia e a farmacoterapia. Este artigo tem como objetivo realizar uma breve revisão bibliográfica dos mais importantes modelos e técnicas cognitivas e comportamentais da fobia social. Os modelos antigos - modelo de déficit de habilidades sociais, modelo de crenças irracionais, modelo da vulnerabilidade cognitiva e os modelos integrativos - serão revisados brevemente. Serão apresentadas as técnicas de tratamento - como a exposição, reestruturação cognitiva, técnicas de relaxamento e treino de habilidades sociais. Estudos de metaanálise sobre a eficácia da terapia cognitivo-comportamental no tratamento da fobia social também serão descritos.La fobia social es uno de los trastornos mentales más prevalentes en la población general. Las principales formas de tratamiento son la psicoterapia y la farmacoterapia. Este artículo posee como objetivo realizar una breve revisión bibliográfica de los más importantes modelos y técnicas cognitivas y comportamentales de la fobia social. Los modelos antiguos - modelo de déficit de habilidades sociales, modelo de creencias irracionales, modelo de la vulnerabilidad cognitiva y los modelos integrativos - serán revisados brevemente. Serán presentadas las técnicas de tratamiento - como la exposición, reestructuración cognitiva, técnicas de relajamiento y entrenamiento de habilidades sociales. Estudios de metaanálisis sobre la eficacia de la terapia cognitivo-comportamental en el tratamiento de la fobia social también serán descritos.Social phobia is a widespread mental disorder in the general population. The main forms of treatment are psychotherapy and pharmacotherapy. This article has as objective to carry out a brief bibliographical review of the most important cognitive and behavior models and techniques of social phobia. The old models - social

Base temperature and simulation model for nodes appearance in cape gooseberry (Physalis peruviana L. Temperatura base e modelo de simulação da aparição de nós em plantas de fisalis(Physalis peruviana L.

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Melba Ruth Salazar

2008-12-01

Full Text Available Data was analyzed on development of the solanaceen fruit crop Cape gooseberry to evaluate how well a classical thermal time model could describe node appearance in different environments. The data used in the analysis were obtained from experiments conducted in Colombia in open fields and greenhouse condition at two locations with different climate. An empirical, non linear segmented model was used to estimate the base temperature and to parameterize the model for simulation of node appearance vs. time. The base temperature (Tb used to calculate the thermal time (TT, ºCd for node appearance was estimated to be 6.29 ºC. The slope of the first linear segment was 0.023 nodes per TT and 0.008 for the second linear segment. The time at which the slope of node apperance changed was 1039.5 ºCd after transplanting, determined from a statistical analysis of model for the first segment. When these coefficients were used to predict node appearance at all locations, the model successfully fit the observed data (RSME=2.1, especially for the first segment where node appearance was more homogeneous than the second segment. More nodes were produced by plants grown under greenhouse conditions and minimum and maximum rates of node appearance rates were also higher.Dados analisados durante o desenvolvimento de fisalis, espécie frutífera da família das solanáceas, foram usados para avaliar a aparição de nós em diferentes condições ambientais através de um modelo clássico termal de tempo. Os dados usados na análise foram obtidos de experimentos conduzidos em dois locais, com clima diferente, em campos abertos e em condições de estufa, na Colômbia. O modelo não-linear empírico segmentado foi usado para estimar a temperatura-base, e para estabelecer os parâmetros do modelo da simulação da aparição de nós em função do tempo. A temperatura-base (Tb usada para calcular o tempo termal (TT, ºCd para a aparição de nós foi 6,29 ºC. A inclina

Armonización de modelos de calidad del software

OpenAIRE

Gabriel Alberto Garcia Mireles; Felix Oscar Garcia Rubio

2013-01-01

La tendencia actual entre las organizaciones que desarrollan software es la adopción de más de un modelo de calidad para estar en condiciones de competir en diversos sectores del mercado. En esa situación, las organizaciones se enfrentan al problema de coordinar la implantación de múltiples modelos de tal manera que cada modelo logre los beneficios esperados, y al mismo tiempo, que los costos y esfuerzo de implantación sean mínimos. Como respuesta a este problema, surge la armonización de mod...

Estudio de distintos modelos de protuberancias solares

Science.gov (United States)

Cirigliano, D.; Rovira, M.; Mauas, P.

En este trabajo presentamos perfiles de líneas del CaII, MgII y HeI calculados para distintos modelos de protuberancias, y los comparamos con observaciones obtenidas por los satélites OSO 8 y SOHO. Para obtener las poblaciones de los distintos niveles de los átomos, utilizamos un código numérico que combina las ecuaciones de transporte de radiación y equilibrio estadístico en un único sistema de ecuaciones no lineal. Los modelos básicos que consideramos para las protuberancias consisten en placas homogéneas y unidimensionales apoyadas sobre la superficie del Sol. Dichas placas se hallan estratificadas en hebras y los modelos difieren entre sí en la temperatura y ancho de la placa, en la presión a la cual se halla el plasma y en el número de hebras. A partir de estos modelos se investiga cada uno de estos parámetros libres y como influyen en la atmósfera de las protuberancias solares y en el perfil de línea de cada especie estudiada, con el objetivo de determinar las condiciones en las que se halla el material atmosférico de estas protuberancias.

MODELO PARA LA INTEROPERABILIDAD DE CONTENIDOS EDUCATIVOS EN DIVERSAS PLATAFORMAS

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Adriana Xiomara Reyes-Gamboa

2014-01-01

Full Text Available Este artículo presenta los resultados del proyecto de interoperabilidad entre plataformas “diseño de un modelo para la interoperabilidad de contenidos educativos en las diversas plataformas basadas en la nube”, el cual busca el correcto despliegue de contenidos audiovisuales en las diferentes plataformas de los dispositivos, el modelo desarrollado se basó en una caracterización de cada una de las plataformas en busca de funcionalidades comunes entre ellas. Este modelo fue validado mediante un caso práctico donde un grupo de personas utilizo el modelo y evaluó su desempeño y despliegue de los contenidos en cada uno de los dispositivos

Status of the segment interconnect, cable segment ancillary logic, and the cable segment hybrid driver projects

International Nuclear Information System (INIS)

Swoboda, C.; Barsotti, E.; Chappa, S.; Downing, R.; Goeransson, G.; Lensy, D.; Moore, G.; Rotolo, C.; Urish, J.

1985-01-01

The FASTBUS Segment Interconnect (SI) provides a communication path between two otherwise independent, asynchronous bus segments. In particular, the Segment Interconnect links a backplane crate segment to a cable segment. All standard FASTBUS address and data transactions can be passed through the SI or any number of SIs and segments in a path. Thus systems of arbitrary connection complexity can be formed, allowing simultaneous independent processing, yet still permitting devices associated with one segment to be accessed from others. The model S1 Segment Interconnect and the Cable Segment Ancillary Logic covered in this report comply with all the mandatory features stated in the FASTBUS specification document DOE/ER-0189. A block diagram of the SI is shown

Effect of tube-support interaction on the dynamic responses of heat exchanger tubes

International Nuclear Information System (INIS)

Shin, Y.S.; Jendrzejczyk, J.A.; Wambsganss, M.W.

1977-01-01

Operating heat exchangers have experienced tube damages due to excessive flow-induced vibration. The relatively small inherent tube-to-baffle hole clearances associated with manufacturing tolerances in heat exchangers affect the tube vibrational characteristics. In attempting a theoretical analysis, questions arise as to the effects of tube-baffle impacting on dynamic responses. Experiments were performed to determine the effects of tube-baffle impacting in vertical/horizontal tube orientation, and in air/water medium on the vibrational characteristics (resonant frequencies, mode shapes, and damping) and displacement response amplitudes of a seven-span tube model. The tube and support conditions were prototypic, and overall length approximately one-third that of a straight tube segment of the steam generator designed for the CRBR. The test results were compared with the analytical results based on the multispan beam with ''knife-edge'' supports

MODELOS DE SISTEMAS MRP CERRADOS INTEGRANDO INCERTIDUMBRE MODELOS DE SISTEMAS MRP FECHADOS INTEGRANDO INCERTEZA CLOSED MODELS OF MRP SYSTEMS CONSIDERING UNCERTAINTIES

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Martín Dario Arango

2012-12-01

Full Text Available En este artículo se muestran cuatro modelos de los sistemas MRP cerrados con incertidumbre en los componentes de producción, como son: la capacidad necesaria de fabricación de cada producto, el tiempo de entrega y la disponibilidad del inventario. Dichos parámetros se tratan mediante la lógica difusa modelizando un sistema MRP cerrado determinista. Por tanto, se presentan inicialmente tres modelos de sistema MRP cerrado, donde cada uno considera de forma independiente la incertidumbre en capacidad, tiempo de entrega y disponibilidad de inventario. Igualmente, se presenta un cuarto modelo de sistema MRP cerrado que de forma conjunta analiza la incertidumbre en los tres parámetros mencionados. Cada uno de estos modelos es validado con información de una empresa del sector eléctrico colombiano, evaluando el costo total del plan de producción, nivel de inventarios, nivel de servicio y complejidad computacional.Neste artigo mostram-se quatro modelos dos sistemas MRP fechados com incerteza nos componentes de produção, como são: a capacidade necessária de fabricação da cada produto, o tempo de entrega e a disponibilidade do inventario. Ditos parâmetros tratam-se mediante a lógica difusa modelando um sistema MRP fechado determinista. Por tanto, apresentam-se inicialmente três modelos de sistema MRP fechado, onde a cada um considera de forma independente a incerteza em capacidade, tempo de entrega e disponibilidade de inventario. Igualmente, apresenta-se um quarto modelo de sistema MRP fechado que de forma conjunta analisa a incerteza nos três parâmetros mencionados. A cada um destes modelos é validado com informação de uma empresa do setor elétrico colombiano, avaliando o custo total do plano de produção, nível de estoques, nível de serviço e complexidade computacional.In this paper, we present four models of uncertainty in the MRP closed systems in the production components, such as: manufacturing capacity of each product

Captura y evaluación del modelo de negocio de las heladerias artesanales

OpenAIRE

Vilchez, María Isabel

2015-01-01

A. Presentación del Proyecto - I. Resumen - II. Marco Teórico - III. Metodología - IV. Objetivos del trabajo - V. Límites o Alcance del trabajo - VI. Organización del trabajo - VII. Introducción - B. Desarrollo del Proyecto.- I. Modelo de Negocio - II. Modelo CANVAS - III. Consumo del Helado en Argentina - IV. Aplicación del modelo CANVAS en el caso de estudio - V. Presentación del modelo de negocio de Heladería Artesanal con Servicio tipo Buffet y recomendaciones al modelo actual de Córdoba ...

Segmented block copolymers with monodisperse aramide end-segments

NARCIS (Netherlands)

Araichimani, A.; Gaymans, R.J.

2008-01-01

Segmented block copolymers were synthesized using monodisperse diaramide (TT) as hard segments and PTMO with a molecular weight of 2 900 g · mol-1 as soft segments. The aramide: PTMO segment ratio was increased from 1:1 to 2:1 thereby changing the structure from a high molecular weight multi-block

Modelo resorte-paríicula para telas hiperlasticas

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MANUEL GARCÍA

2007-01-01

Full Text Available Este artículo presenta un modelo computacional para la simulación de telas hiperelásticas. El modelo propuesto tiene un enfoque multi−partículas y simula la interacción de un material textil con un objeto deformante. La tela está representada por mallas rectangulares compuestas por resortes, este hecho permite al modelo comportarse ortotrópicamente y en consecuencia es posible simular sus propiedades en ambos sentidos. Las relaciones constitutivas del material preservan las capacidades hiperelásticas naturales de la tela. En el modelo desarrollado aquí, inicialmente la tela se encuentra en su estado natural no deformado. Luego se le da una deformación inicial que garantice el no contacto o intersección con el objeto deformante. Finalmente, la tela deformada es liberada, en consecuencia ella comienza a moverse iterativamente hacia a una posición de equilibrio. La posición final de equilibrio es alcanzada cuando las fuerzas internas son balanceadas por las fuerzas externas de contacto causadas por el objeto. Esto se logra cuando el criterio de parada ha sido satisfecho.

Modelo genérico de celdas fotovoltaicas

OpenAIRE

Fernández, Herman; Martínez, Abelardo; Guzmán, Víctor Manuel; Giménez, María Isabel

2008-01-01

Este trabajo presenta el modelado y la simulación en PSpice de un circuito que se comporta eléctricamente como un panel solar. El modelo permite seleccionar un circuito que representa una única celda o combinaciones de múltiples celdas solares conectadas en serie y paralelo. La evaluación del modelo se realiza mediante una herramienta computacional, que permite ingresar parámetros relacionados con el número de celdas conectadas en distintas configuraciones serie-paralelo, las resistencias de ...

Segmentation of consumer's markets and evaluation of market's segments

OpenAIRE

ŠVECOVÁ, Iveta

2013-01-01

The goal of this bachelor thesis was to explain a possibly segmentation of consumer´s markets for a chosen company, and to present a suitable goods offer, so it would be suitable to the needs of selected segments. The work is divided into theoretical and practical part. First part describes marketing, segmentation, segmentation of consumer's markets, consumer's market, market's segments a other terms. Second part describes an evaluation of questionnaire survey, discovering of market's segment...

Frequency and Magnitude Analysis of the Macro-instability Related Component of the Tangential Force Affecting Radial Baffles in a Stirred Vessel

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P. Hasal

2002-01-01

Full Text Available Experimental data obtained by measuring the tangential component of force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with pitched blade impellers is analysed. The maximum mean tangential force is detected at the vessel bottom. The mean force value increases somewhat with decreasing impeller off-bottom clearance and is noticeably affected by the number of impeller blades. Spectral analysis of the experimental data clearly demonstrated the presence of its macro-instability (MI related low-frequency component embedded in the total force at all values of impeller Reynolds number. The dimensionless frequency of the occurrence of the MI force component is independent of stirring speed, position along the baffle, number of impeller blades and liquid viscosity. Its mean value is about 0.074. The relative magnitude (QMI of the MI-related component of the total force is evaluated by a combination of proper orthogonal decomposition (POD and spectral analysis. Relative magnitude QMI was analysed in dependence on the frequency of the impeller revolution, the axial position of the measuring point in the vessel, the number of impeller blades, the impeller off-bottom clearance, and liquid viscosity. Higher values of QMI are observed at higher impeller off-bottom clearance height and (generally QMI decreases slightly with increasing impeller speed. The QMI value decreases in the direction from vessel bottom to liquid level. No evident difference was observed between 4 blade and 6 blade impellers. Liquid viscosity has only a marginal impact on the QMI value.

Generación de código Hibernate desde modelos UML

OpenAIRE

Nogueiro Mariscal, Alejandro

2012-01-01

Este proyecto consiste en un generador de código para Hibernate desde modelos UML. El código generado es el conjunto de clases del modelo implementadas en Java con una serie de anotaciones JPA 2.0. Estas clases, mediante Hibernate, sirven para añadir persistencia a nuestro código. Los modelos UML tendrán una serie de anotaciones para poder transformarlos correctamente.

Modelo cinematico del mini robot movil Ricimaf

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Abelardo del Pozo Quintero

2012-12-01

Full Text Available El presente trabajo describe el modelo dinámico del mini robot móvil construido en el Icimaf, cuya  tracción se logra mediante dos motores de paso acoplados a dos ruedas plásticas forradas con una capa de goma para facilitar su  movimiento y una pequeña rueda direccional. Se elabora la estructura jacobiana necesaria para el desarrollo del modelo dinámico. Se incluye el análisis de un rasgo especial de estos robots, que  es su naturaleza no holonómica, en contraste  con los robots manipuladores, lo que da lugar a un tipo de restricción del movimiento. La elaboración del modelo dinámico originó el empleo de los multiplicadores de Lagrange. Para la obtención de las ecuaciones dinámicas se emplea el método de Euler-Lagrange

Apparatus for leaching core material from clad nuclear fuel pin segments

International Nuclear Information System (INIS)

Yarbro, O.O.

1980-01-01

This invention relates to improved apparatus for countercurrently contacting liquids and solids to dissolve, or leach, a selected component of the solids while minimizing back-mixing of the liquid phase. The apparatus includes an elongated drum which is rotatable about its longitudinal axis in either direction and is partitioned radially into a solids-inlet/liquid-outlet compartment at one end, a solids-outlet/liquid-inlet compartment at its other end, and leaching compartments therebetween. The drum is designed to operate with its acid-inlet end elevated and with the longitudinal axis of the drum at an angle in the range of from about 3* to 14* to the horizontal. Each leaching compartment contains a chute assembly for advancing solids into the next compartment in the direction of solids flow when the drum is rotated in a selected direction. The chute assembly includes a solids-transfer baffle and a chute in the form of a slotted, skewed, conical frustum portion. When the drum is rotated in the direction opposite to that effecting solids transfer, the solids-transfer baffles continually separate and re -mix the solids and liquids in their respective compartments. The partitions defining the leaching compartments are formed with corresponding outer, annular, imperforate regions, each region extending inwardly from the partition rim to an annular array of perforations concentric with the rim. In each leaching compartment, the spacing between the rim and the perforations determines the depth of liquid at the liquid-outlet end of the compartment. The liquid input to the drum assembly flows continuously through the compartments, preventing back-mixing due to density differences, whereas backflow due to waves generated by the solids-transfer baffles is virtually eliminated because of the tilted orientation of the drum assembly

El MOOC: ¿un modelo alternativo para la educación universitaria?

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Carlos Ruiz Bolívar

2015-10-01

Full Text Available El propósito de este trabajo es realizar una reflexión crítica sobre el modelo educativo MOOC a partir de la información proveniente de la literatura especializada y de nuestra propia experiencia como usuario. Nos propusimos dar respuesta a la pregunta ¿cuál es la intención y el alcance real del MOOC como modelo educativo emergente?; es decir, ¿es realmente el MOOC una alternativa válida frente al modelo tradicional de la educación superior? La revisión de la literatura revela que dicho modelo representa una opción real de democratización del conocimiento, ya que brinda acceso libre a todo usuario que lo desee, sin otra limitación que tener un dispositivo con conexión a internet, el deseo de aprender y la motivación genuina para hacerlo. Sin embargo, como toda innovación, este modelo educativo tiene partidarios y detractores. Los MOOC, aun cuando han sido impulsados por prestigiosas universidades internacionales, no han sido creados para sustituir el modelo universitario clásico; no obstante, se espera que como modelos educativos abiertos tendrán un impacto importante tanto en la educación a distancia actual como en el modelo educativo universitario tradicional, incluyendo el cambio de roles de sus actores principales (profesores y estudiantes en el proceso educativo.

A horizontal plug-flow baffled bioelectrocatalyzed reactor for the reductive decolorization of Alizarin Yellow R.

Science.gov (United States)

Sun, Qian; Li, Zhiling; Wang, Youzhao; Cui, Dan; Liang, Bin; Thangavel, Sangeetha; Chung, Jong Shik; Wang, Aijie

2015-11-01

An application-oriented membrane-free, continuous plug-flow baffled bioelectrocatalyzed reactor (PFB-BER), was designed and testified for the decolorization of Alizarin Yellow R. Decolorization efficiency (DE) with an external power source of 0.5 V was higher than without electrolysis, i.e. 93.4% versus 73.6% (HRT of 24 h). Product formation efficiencies of p-phenylenediamine and 5-aminosalicylic acid were above 95% and 50%, respectively. When HRT decreased to 8 h and 4 h, DE reduced to 69.9% and 44.9%, respectively. An additional electrode assembly improved DE to 96.4% (HRT of 8 h) and 80% (HRT of 4 h), while energy consumption (HRT of 4 h) was lower than that of HRT of 12 h with single electrode assembly under comparable DE. The PFB-BER with higher removal capacity, lower internal resistance and energy consumption provides a new solution to treat the high loading azo dye-containing wastewaters. Copyright © 2015. Published by Elsevier Ltd.

Control of Malaria Vector Mosquitoes by Insecticide-Treated Combinations of Window Screens and Eave Baffles.

Science.gov (United States)

Killeen, Gerry F; Masalu, John P; Chinula, Dingani; Fotakis, Emmanouil A; Kavishe, Deogratius R; Malone, David; Okumu, Fredros

2017-05-01

We assessed window screens and eave baffles (WSEBs), which enable mosquitoes to enter but not exit houses, as an alternative to indoor residual spraying (IRS) for malaria vector control. WSEBs treated with water, the pyrethroid lambda-cyhalothrin, or the organophosphate pirimiphos-methyl, with and without a binding agent for increasing insecticide persistence on netting, were compared with IRS in experimental huts. Compared with IRS containing the same insecticide, WSEBs killed similar proportions of Anopheles funestus mosquitoes that were resistant to pyrethroids, carbamates and organochlorines and greater proportions of pyrethroid-resistant, early exiting An. arabiensis mosquitoes. WSEBs with pirimiphos-methyl killed greater proportions of both vectors than lambda-cyhalothrin or lambda-cyhalothrin plus pirimiphos-methyl and were equally efficacious when combined with binding agent. WSEBs required far less insecticide than IRS, and binding agents might enhance durability. WSEBs might enable affordable deployment of insecticide combinations to mitigate against physiologic insecticide resistance and improve control of behaviorally resistant, early exiting vectors.

El suspenso del melodrama. Entre modelos narrativos y modelos de conducta

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Álvaro A. Fernández Reyes

2008-01-01

Full Text Available Al final de la llamada Época de Oro, el cine mexicano adapta sus formas de representación para reconstruir tanto sus modelos y estrategias narrativas como sus nuevos sujetos representados, desplegando, no obstante, una tensión entre la modernidad y la lucha por conservar valores pretéritos. En la película Que Dios me perdone (Tito Davison, 1947 indago el carácter cambiante de una tradición impresa en la expresión artística masificada. Con el estudio del caso, abordo la representación de la mujer moderna de los años cuarenta en sus roles fundamentales para la construcción simbólica del género y sus modelos de conducta; detecto la manera en que se comporta ese género en tensión con la retórica del suspenso y del melodrama, centrándome en las desviaciones y regulaciones del ideal materno y de su inherente conflicto sexual en escenarios y situaciones extraordinarias para este rol: convóquese a la maternidad negada, al crimen o al espionaje.

Modelo integrador de estrategias competitivas: aplicación al sector portuario

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Luis Silva-Domingo

2010-12-01

Full Text Available A pesar de los importantes avances de la literatura y la práctica profesional, los modelos teóricos de estrategia competitiva aún no han alcanzado su madurez. En este trabajo se exponen y discuten distintas visiones sobre los modelos de estrategias competitivas, defendiendo la necesidad de un desarrollo que integre los aspectos clave en la posición competitiva de las organizaciones: el entorno y las capacidades de la organización. En este sentido, el objetivo es resaltar el potencial del modelo integrador de estrategias competitivas propuesto por Parnell (2006, el que aún no cuenta con suficiente evidencia empírica. A través de la reflexión teórica aplicando conceptualmente el modelo en el sector portuario de cargas –que se describe y analiza brevemente-, este trabajo concluye que el modelo referido puede resultar de gran relevancia para la práctica profesional y, consecuentemente, para la academia

Modelo artesanal para treinamento de acesso vascular periférico

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Ingrid Rodrigues de Oliveira Rocha

2017-08-01

Full Text Available Resumo Contexto O acesso vascular é o procedimento mais comum realizado entre pacientes hospitalizados. Assim, na tentativa de minimizar complicações e aliar conhecimento técnico ao conhecimento teórico, os modelos de simulação são capazes de oferecer um ambiente seguro para profissionais em formação e evitar os dilemas éticos de treinamento direto em pacientes. Com esse objetivo, surgiram diversos manequins de treinamento, mas devido ao seu alto custo eles não são acessíveis a todos, e com frequência os profissionais em formação da área da saúde realizam procedimentos sem que tenham um treinamento prévio. Objetivo Desenvolver um modelo de ensino e treinamento de acesso vascular periférico, utilizando um modelo de baixo custo para fins educacionais. Método Para reproduzir a via periférica de acesso, utilizou-se um macarrão de polietileno com equipos de infusão, com uma extremidade em fundo cego e a outra conectada a duas bolsas de 500 mL de soro fisiológico acrescido de corante. A bolsa foi instalada em um suporte metálico. Resultado O formato sugerido para o modelo apresentou semelhança com a anatomia do antebraço simplificada. O modelo se mostrou prático na punção e, devido à sua extensão, tem-se a possibilidade de puncionar diversas vezes o mesmo modelo, facilitando o treinamento. Conclusão O modelo proposto permite o treinamento de acesso vascular periférico, sendo uma alternativa de baixo custo que pode ser utilizada para fins educacionais.

Metadecisão no modelo de gestão toyotista

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Alvair Silveira Torres Júnior

2010-12-01

Full Text Available O processo decisório no modelo de produção enxuta aparece como um fator pouco explorado na literatura. Os elementos que compõem o processo decisório aparecem marginalmente quando se discutem fatores como just-in-time, as parcerias com fornecedores, o desenvolvimento de produtos e a qualidade embutida no processo. O objetivo desta pesquisa é explorar como o processo decisório se apresenta no modelo de produção enxuta. Foram desenvolvidas entrevistas em profundidade com três ex-executivos do primeiro e médio escalão da subsidiária brasileira da Toyota Motor. Os entrevistados foram escolhidos intencionalmente e por oportunidade. Os resultados apresentam um conjunto de elementos do modelo de produção enxuta, denominados na literatura processos de solução de problemas, organizados em uma disposição própria, aqui reconhecida como uma metadecisão, a qual estrutura de forma peculiar o processo decisório do modelo Toyota. A contribuição deste trabalho é tornar explícita a estrutura de metadecisão do modelo de produção enxuta.

Modelo de aseguramiento de la calidad en el proceso de desarrollo de software basado en los modelos de madurez de capacidades (CMMi), proceso de software para equipos (TSP) y personas (PSP)

OpenAIRE

Espejo Chavarría, Alex José

2016-01-01

Genera e implementa un modelo de aseguramiento de la calidad en el proceso de desarrollo de software con un enfoque orientado al factor humano; factor que es responsable de introducir y gestionar la calidad en el proceso de desarrollo de software. El modelo propuesto se basa en tres modelos “Modelos de Madurez de Capacidades Integrado, Proceso de Software para Equipos y Proceso de Software para Personas. Tesis

Modelos de enseñanza y modelos de comunicación en las clases de ciencias naturales

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Laura Levin

2009-09-01

Full Text Available El objetivo de la investigación relatada en este trabajo fue analizar si el estilo de enseñanza al que dice adherir el profesorado de ciencias naturales se expresa en las diversas formas de comunicación que se establecen en sus clases. El foco de la observación de clases estuvo principalmente en las interacciones lingüísticas entre profesor/a y estudiantes. La enseñanza y la comunicación se tipificaron con diversos modelos teóricos, que aquí se revisan. A partir del análisis de las clases observadas se robustecen las siguientes precisiones: a el modelo “didáctico” constructivista necesita en algún momento del despliegue efectivo de una comunicación dialógica en el aula; b por tanto, “adherir” declarativamente al constructivismo mientras se generan modos de comunicación clausurantes en clase deja al descubierto modelos implícitos de transmisión o de condicionamiento; c sin embargo, en las aulas argentinas se observan tipos híbridos de práctica en donde el lenguaje asume muchos papeles.

Modelo de capacidades e maturidade para defesa cibernética

OpenAIRE

Sylvio Andre Diogo Silva

2011-01-01

Uma implantação eficaz de defesa cibernética requer o desenvolvimento de esforços coordenados nas seguintes capacidades-chave: detecção de ataques, mecanismos de defesa, monitoramento de situação, comando e controle, aprimoramento de estratégias e táticas e desenvolvimento seguro de sistemas. A dissertação apresenta um modelo de capacidades para defesa cibernética. A partir das seis capacidades-chave, foi identificado um modelo com capacidades essenciais para a defesa cibernética. O modelo de...

En busca de un posicionamiento de mercado: Modelo de Mercadotecnia

OpenAIRE

Nancy Imelda Montero Delgado; Daniel Muñoz Zapata; Sergio Octavio Vázquez Núñez

2016-01-01

Esta investigación nace con la finalidad de identificar las variables que inciden en el diseño efectivo de una estrategia de mercadotecnia, de tal forma que el empresario implemente acciones que lo lleven a mejorar la posición en el mercado y su reflejo en el nivel de ventas. Para esto, se observan los modelos que han intentado explicar la efectividad de la mercadotecnia en el tiempo; partiendo así del modelo de Kotler (1977) y se integran los hallazgos identificados en otros modelos, así com...

Intervención en Proyecto Hombre desde un Modelo Biopsicosocial

OpenAIRE

Ramirez Córdoba, Myriam

2016-01-01

En Proyecto Hombre asumimos que el modelo que mejor explica el fenómeno de las adicciones es el Modelo Bio-psico-social. Este modelo defiende que las adicciones vienen causadas por múltiples factores y no por un factor único. Estos factores serían: Factores Biológicos, Factores Psicológicos (lo que implica pensamientos, emociones y conductas), y Factores Sociales. Todos ellos juegan un papel importante en el funcionamiento humano en el contexto de las adicciones y de la percepción que se tie...

Comprehensive study for Anammox process via multistage anaerobic baffled reactors

Science.gov (United States)

Ismail, Sherif; Tawfik, Ahmed

2017-11-01

Continuous anaerobic ammonia oxidation (Anammox) process in multistage anaerobic baffled (MABR) reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT) of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L). The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN) removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR) of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h). Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

Modelo de negocio para bebidas funcionales Ceiba

OpenAIRE

Gil Giraldo, Jhonatan; Restrepo Mesa, Juan Eduardo

2017-01-01

El presente documento, modelo de negocio para bebidas naturales Ceiba, es el trabajo de grado realizado por los autores con el fin de optar al título de magíster en Administración (MBA) de la Universidad EAFIT -- El cual esta soportado en los diferentes conceptos y metodologías de modelo de negocio y planes de negocio -- Por tratarse de un prototipo que busca definir los elementos estratégicos necesarios para su desarrollo, arrojó como resultado que la metodología más adecuada para ser aplica...

Photo-fermentative hydrogen production in a 4m3 baffled reactor: Effects of hydraulic retention time.

Science.gov (United States)

Zhang, Quanguo; Lu, Chaoyang; Lee, Duu-Jong; Lee, Yu-Jen; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Wang, Yi; Jiang, Danping; He, Chao; Zhang, Tian

2017-09-01

A 4m 3 pilot-scale baffled continuous-flow photoreactor with four sequential chambers (#1-#4) was established and tested to evaluate its photo-fermentative hydrogen production from wastewater that contains (10g/L glucose using a functional consortium at 30°C, under light with an intensity of 3000±200lux with a hydraulic retention time (HRT) of 24-72h. The hydrogen production rate and the broth characteristics varied significantly in the flow direction. The hydrogen production rate was highest in chamber #1, and lower in chambers #2-#4 at an HRT of 72h, while the peak production rate shifted to the latter chambers as the HRT was shortened. The overall H 2 production rate increased as HRT decreased, but was not consistent with the predictions that were based on the complete-mixing assumption. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arc erosion of full metal plasma facing components at the inner baffle region of ASDEX Upgrade

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V. Rohde

2016-12-01

Full Text Available At the inner baffle of the AUG divertor massive polished inserts of tungsten and P92 steel were installed to measure the erosion by arcing. For tungsten most of the traces are less than 0.4µm deep and a similar amount of tungsten is deposited close to the traces. Few craters up to 4µm resulting in an average erosion rate of 2×1013 at cm−2s−1 are observed. The behaviour for P92 steel is quite different: most of the traces are 4µm deep, up to 80µm were observed. An average erosion rate of 400×1013 at cm−2s−1, i.e. more than a factor of hundred higher compared to tungsten, is found. Therefore, erosion by arcing has to be taken into account to determine the optimal material mix for future fusion devices.

Evaluation of Baffle Fixes Film up Flow Sludge Blanket Filtration (BFUSBF System in Treatment of Wastewaters from Phenol and 2,4-Dinitrophenol Using Daphnia Magna Bioassay

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Mohammad Javad Ghannadzadeh

2016-02-01

Full Text Available Background: Phenol and nitrophenol are common compounds found in different types of industrial wastewater known as serious threats to human health and natural environment. In this study, Daphnia magna was used to evaluate the effectiveness of "baffle fixes film up flow sludge blanket filtration" (BFUSBF system in elimination of phenolic compounds from water. Methods: D. magna cultures were used as toxicity index of phenol and 2,4-DNP mixtures after treatment by a pilot BFUSBF system which consisted of baffle in anoxic section and biofilm in aerobic sections. Initial concentrations were 312 mg/L phenol and 288 mg/L 2,4-dinitrophenol (2,4-DNP. Results: Bioassay tests showed that D. magna was influenced by the toxicity of phenol and 2,4 DNP mixtures. The comparison between the toxicity of initial phenol and 2,4-DNP mixtures and the output toxic unit (TU derived from BFUSBF treatment system showed that the TU of the effluent from BFUSBF reactor was much lower than that of the solution that entered the reactor. Conclusion: Based on the acute toxicity test, BFUSBF process could reduce phenol and 2,4-DNP in aqueous solutions. Therefore, it is possible to use BFUSBF process as an appropriate treatment option for wastewaters containing phenolic compounds.

Previsão de demanda: uma aplicação dos modelos Box-Jenkins na área de assistência técnica de computadores pessoais Demand forecasting: an application of the Box-Jenkins models in the technical assistance of personal computer

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Liane Werner

2003-04-01

Full Text Available A previsão de demanda é uma atividade importante para auxiliar na determinação dos recursos necessários para a empresa. Neste artigo, a metodologia de Box-Jenkins foi utilizada para analisar dados históricos de uma empresa de assistência técnica de computadores pessoais e obter previsões do número de atendimentos. A empresa estudada apresenta três tipos de clientes diferenciados: contratos, garantia e avulsos. Como cada segmento de clientes tem suas peculiaridades, a previsão de demanda foi direcionada a cada tipo, buscando representar o comportamento de tendência e a sazonalidade por meio dos modelos de Box-Jenkins. A obtenção dos modelos mais adequados foi baseada na análise de gráficos e em testes estatísticos próprios da metodologia, os quais subsidiaram a decisão de adotar o modelo AR(1 para prever o número de atendimentos dos clientes tipo contrato, o modelo ARIMA(2,1,0 para os clientes tipo garantia e um modelo sazonal SARIMA(0,1,0(0,1,112 para os clientes tipo avulsos.Demand forecasting is an important tool to aid on the determination of necessary resources of a given company. In this paper, the Box-Jenkins methodology was applied to analyze historical data of a personal computer repair company and provide a forecast for the number of service calls. The company studied presents three segments of clients: contracts, warranty, and on-call. As each client has it own characteristics, in order to better represent tendency and seasonality behavior through the Box-Jenkins models, a specific forecasting model was developed for each segment. The choice of the optimum models were based into graphic analysis and statistical tests, which lead to the decision of adopting the AR(1 model to foresee the number of contract clients, the ARIMA(2,1,0 model for warranty clients and the SARIMA(0,1,0(0,1,112 seasonal model for on-call clients.

Ecuador. Modelo de consumo y prevención

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Jack Laufer

2015-01-01

Full Text Available Dossier Comunicación y Drogas. El autor presenta la construcción de un modelo antidrogas, basado en la dinámica de sistemas. Plantea la propia conceptualización del modelo, los lineamientos básicos de un sistema de consumo y prevención de drogas y destaca los roles determinantes que deben ejercer los medios y la opinión pública. ¡Es muy útil y novedoso!

Modelos contables y comprensión de la crisis financiera

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Dirk J. Bezemer

2012-06-01

Full Text Available Este artículo muestra que los modelos macroeconómicos contables ayudaron a prever la crisis de crédito y la recesión económica, mientras que los modelos de equilibrio ubicuos en la formulación de política y la investigación de la corriente principal no. Explora los antecedentes intelectuales del enfoque contable como alternativa a la economía neoclásica y el ascenso y declive de los modelos de flujo de fondos durante la posguerra. Incluye estudios de caso actuales de ambos tipos de modelos y analiza por qué el enfoque contable se ha mantenido fuera de la corriente dominante. Hace recomendaciones constructivas para revisar los métodos de evaluación de la estabilidad financiera y aboga por una “contabilidad de la economía”.

En busca de un posicionamiento de mercado: Modelo de Mercadotecnia

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Nancy Imelda Montero Delgado

2016-03-01

Full Text Available Esta investigación nace con la finalidad de identificar las variables que inciden en el diseño efectivo de una estrategia de mercadotecnia, de tal forma que el empresario implemente acciones que lo lleven a mejorar la posición en el mercado y su reflejo en el nivel de ventas. Para esto, se observan los modelos que han intentado explicar la efectividad de la mercadotecnia en el tiempo; partiendo así del modelo de Kotler (1977 y se integran los hallazgos identificados en otros modelos, así como la inserción de una variable adicional que pretende explicar con mayor claridad el nivel de mercadotecnia que emplea la empresa. Como resultado se propone un modelo aplicable a la mipyme a través del cual el empresario identifica en forma clara y sencilla el nivel de mercadotecnia con el que trabaja y su efectividad

Modelos de Requisitos Basados en I* para Detectar Proactividad en Dashboards

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Alain Pérez-Acosta

2014-06-01

Full Text Available El objetivo del trabajo es presentar modelos para la captura de los requisitos de un dashboard para detectar un comportamiento proactivo. Estos modelos siguen un enfoque orientado hacia metas y fueron creados con el marco de trabajo i*, que toma como base las premisas del modelado social. Para detectar el comportamiento proactivo se usaron patrones basados en modelos de i* para detectar proactividad en la etapa de requisitos de un sistema de software. Los modelos que se obtienen como resultado del trabajo tienen representados los actores, metas, intenciones, tareas y recursos que se necesitan para modelar los requisitos de un dashboard con un comportamiento proactivo y pueden, además, ser utilizados en distintos contextos de negocio.

GRUPO EMPRESARIAL ANTIOQUEÑO 1978-2002 ANÁLISIS DEL MODELO EMPRESARIAL

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Carlos Felipe Londoño

Full Text Available Como se había planteado en el artículo "Grupo Empresarial Antioqueño. Evolución de políticas y estrategias, 1978-2002", publicado en el número 1 de la Revista EIA, el análisis de las políticas y estrategias del GEA debe conducir a un modelo que permita pensar y estructurar el futuro del Grupo, a la luz de los cambios que afronta el país y el mundo. En esta oportunidad se presenta un análisis DOFA del modelo histórico del GEA, denominado .modelo de enroque., con una propuesta de un nuevo esquema de gobierno que responda en forma oportuna a las circunstancias cambiantes del mundo: el modelo de "holdings".

Los modelos explicativos del estudiantado acerca de la célula eucarionte animal

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Johanna Patricia Camacho González

2012-01-01

Full Text Available El principal objetivo de esta investigación fue analizar los modelos explicativos del estudiantado de 8vo básico, acerca de la estructura de la célula eucarionte animal, antes y después de una intervención didáctica, fundamentada desde el Modelo Cognitivo de Ciencia (Giere, 1992 y estructurada según el Ciclo Constructivista de Aprendizaje (Sanmartí, 2000. La investigación se desarrolló en dos fases: a. En la fase descriptiva interpretativa, se categorizaron los modelos explicativos identificados en 18 familias de modelos y b. En la fase pre-experimental, se identificó sí existían diferencias significativas entre dichos modelos antes y después de la intervención didáctica a través, de las técnicas estadísticas de Wilcoxon y ANOVA de aleatoriedad de datos. Los principales hallazgos evidenciaron que la intervención didáctica favorece la construcción de modelos explicativos dinámicos y flexibles, que se caracterizan por poseer un lenguaje más especializado, establecer nuevas relaciones entre los organelos y funciones celulares, así como la capacidad de incorporar nuevos elementos para enriquecer el modelo de célula escolar, demostrando así que estos modelos se transforman progresivamente (Rodríguez y Moreira, 1999; Justi, 2006.

Prueba para el error de ajuste de un modelo multivariante

OpenAIRE

Rodríguez, Luis H.

2012-01-01

En el ajuste de un modelo a una serie de observaciones se presenta el interesante problema de decidir sobre lo adecuado del modelo para describir tales observaciones .. Una prueba para esta clase de decisión se denomina "Error de ajuste", No conocíamos una tal prueba para el caso de un modelo multivariante  (cada observación es un vector), por lo que este articulo hacemos una extensión de la  técnica de  "error de ajuste" utilizada en el análisis  univariante al caso multivariante,  y se prod...

Comparación de la satisfacción de los usuarios de atención domiciliaria: modelo integrado vs. modelo dispensarizado

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Marta Gorina

2014-06-01

Conclusiones: El grado de satisfacción de los pacientes de atención primaria domiciliaria parece depender de las características propias de cada modelo organizativo, siendo el modelo dispensarizado el que presenta un mayor grado de satisfacción o calidad asistencial percibida. Se debería realizar un mayor número de estudios para generalizar estos resultados a otros centros de atención primaria pertenecientes a otras instituciones.

UM MODELO INFORMACIONAL PARA EMPRESAS MULTIPLANTA

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Rogério Matos Dias

2006-09-01

Full Text Available Este estudo objetiva conceber, testar e demonstrar a aplicabilidade de um modelo informacional que possibilite a gestão integrada das operações da cadeia de suprimentos para firmas geograficamente dispersas – também denominadas empresas multiplanta. Para tanto, foram aplicados os métodos de pesquisa de caso e pesquisa-ação em uma empresa representativa do setor mínero-metalúrgico em âmbito mundial, a Rio Doce Manganês S.A., subsidiária da Cia. Vale do Rio Doce. A pesquisa pretende demonstrar que o modelo de sistema informacional proposto, por meio da automatização dos processos transacionais e gerenciais, é capaz de prover recursos de planejamento e controle nos níveis operacional, tático e estratégico, devido a sua capacidade de incrementar velocidade e qualidade nos processos de análise e decisão. Adicionalmente, pretende conduzir, após análise dos resultados e avaliação das contribuições a empresa estudada, a um modelo informacional adequado para gerir as operações de outras empresas de mineração e metalurgia com características semelhantes.

Clima organizacional: análise fatorial confirmatória de modelos de mensuração concorrentes

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Daniel Ioshiteru Kinpara

Full Text Available O objetivo deste trabalho foi verificar qual modelo de mensuração para a Escala Clima Organizacional (ECO ajusta-se melhor aos dados. Quatro modelos concorrentes foram comparados: 1 o modelo de sete fatores de Laros e Puente-Palacios; 2 um modelo de cinco fatores derivado do modelo anterior; 3 um modelo de seis fatores baseado na teoria de campo vital de Lewin; e 4 um modelo de três fatores baseado na teoria de motivação de McClelland. Foram analisados os dados de 9.901 respondentes da ECO. Os resultados de análise fatorial confirmatória indicaram o modelo de três fatores como o melhor. Todos os modelos mostram ajuste suficiente aos dados. Sugere-se que a escolha do modelo baseie-se na finalidade de uso da escala.

Modelo de Comportamiento Afectivo para Sistemas Tutores Inteligentes

OpenAIRE

Hernández Pérez, María Y.

2008-01-01

Las emociones se han reconocido como parte fundamental de la motivación, y la motivación como un componente indispensable en el aprendizaje. En este documento se propone un modelo de comportamiento afectivo para sistemas tutores inteligentes. Dicho modelo combina el estado afectivo y pedagógico de los estudiantes para establecer las acciones tutoriales. En el contexto de este trabajo, el comportamiento afectivo tiene dos funciones principales: 1) inferir el estado afectivo del estudiante; y 2...

Modelo de competencias del profesor de medicina

Directory of Open Access Journals (Sweden)

A. Martínez-González

Full Text Available Objetivo. Generar el modelo de competencias del profesor para ejercer la docencia de alto nivel en Medicina. Materiales y métodos. Para generar el modelo se analizó la bibliografía, el propósito del plan de estudio por competencias y se utilizó el método Developing a Curriculum (DACUM, con la participación de 35 expertos que integraron mediante consenso el trabajo que debe realizar un docente de medicina para cumplir con éxito el propósito del plan de estudio. Resultados. Se identificaron las funciones básicas de los profesores de medicina, así como las actividades para su cumplimiento. Se conformó el modelo con seis competencias: disciplinaria, de investigación, psicopedagógica, de comunicación, académico-administrativa y humanística. Conclusiones. El modelo pretende guiar las acciones de los profesores que actualmente participan en el programa y aquellos que aspiran a formar parte del proceso educativo; elaborar programas para la formación de profesores que favorezcan el desarrollo de competencias académicas; identificar elementos que se deben considerar para la evaluación del desempeño docente; orientar el diseño de indicadores útiles para otorgar reconocimientos y estímulos a los profesores cuyo desempeño académico sea excepcional; orientar al estudiante, en la relación profesor-alumno, sobre las funciones y actividades que puede esperar del profesor.

Análisis de la apertura comercial en México mediante modelos multisectoriales, 1970-93.

OpenAIRE

Chapa Cantú, Joana Cecilia

2003-01-01

En esta tesis se analiza y calcula el impacto de la apertura comercial mexicana y el efecto marginal del TLCAN sobre la estructura productiva, niveles de actividad y redistribución de recursos. Esta política es analizada en un entorno de interdependencia general, implementando tres modelos multisectoriales y estáticos: Modelo Input-Output, Modelo Lineal SAM o de Multiplicadores Contables y un Modelo de Equilibrio General Computable (MEGC). El Modelo Input-Ouput permite calcular indicadores de...

Las emociones en el deporte: conceptos empleados en un modelo tridimensional

OpenAIRE

Latinjak, Alexander T.; López Ros, Víctor; Font Lladó, Raquel

2014-01-01

La psicología del deporte utiliza modelos dimensionales para organizar el complejo mundo de las emociones. Este trabajo estudia los conceptos empleados en el modelo de Latinjak (2012), que incorpora la perspectiva temporal a las dimensiones tradicionales de valor y activación en el ámbito deportivo. El objetivo principal del presente estudio fue determinar los conceptos más pertinentes para las ocho emociones principales del modelo. Para ello se realizó una investigación en tres etapas consis...

Las emociones en el deporte : conceptos empleados en un modelo tridimensional

OpenAIRE

Latinjak, Alexander T.

2014-01-01

La psicología del deporte utiliza modelos dimensionales para organizar el complejo mundo de las emociones. Este trabajo estudia los conceptos empleados en el modelo de Latinjak (2012), que incorpora la perspectiva temporal a las dimensiones tradicionales de valor y activación en el ámbito deportivo. El objetivo principal del presente estudio fue determinar los conceptos más pertinentes para las ocho emociones principales del modelo. Para ello se realizó una investigación en tres etapas consis...

MODELOS CONSTITUTIVOS DRUCKER PRAGER EXTENDIDO Y DRUCKER PRAGER MODIFICADO PARA SUELOS RHODIC FERRALSOL

Directory of Open Access Journals (Sweden)

Omar González Cueto

2014-10-01

Full Text Available La aplicación del Método de Elementos Finitos (MEF a la solución de problemas de compactación del suelo, para las condiciones tropicales, necesita de modelos constitutivos validados para estos tipos de suelos. El objetivo del presente trabajo fue validar los modelos constitutivos Drucker Prager Extendido (DPE y Drucker Prager Modificado (DPM para un suelo Rhodic Ferralsol. La metodología empleada incluyó el desarrollo, en el software Abaqus/Standard 6.8-1, de un modelo en MEF que simula un ensayo triaxial, a partir del cual se predijo la curva esfuerzo-deformación del suelo. Las propiedades del material se representaron con los modelos constitutivos DPE y DPM. Para la validación de los modelos se realizaron ensayos triaxiales a probetas remoldeadas del suelo objeto de estudio. Los estadísticos de Kolmogorov-Smirnov (P < 0.05, demostraron el adecuado ajuste entre resultados experimentales y predicciones, cuando se utilizan los modelos constitutivos DPE y DPM para representar la respuesta mecánica del suelo Rhodic Ferralsol, tanto en condiciones de falla frágil como plástica. Los resultados validan ambos modelos constitutivos para su empleo como modelos del material en la implementación del MEF a la solución de problemas de compactación del suelo. El modelo DPE demanda menor capacidad computacional, requiere menor cantidad de parámetros constitutivos y estos se puedan obtener con el equipamiento tradicionalmente disponible en los laboratorios de mecánica de suelos, lo cual lo hace más asequible para su utilización.

Modelos de horno de arco eléctrico para estudios del efecto flicker

Directory of Open Access Journals (Sweden)

Catalina González Castaño

2016-06-01

Full Text Available Objetivo: El objetivo de este artículo es evaluar las fluctuaciones de voltaje o flicker de dos modelos de un horno de arco eléctrico a través de la comparación con datos reales. Método: El primer modelo se fundamenta a partir del principio de conservación de la energía, de la cual se obtiene una ecuación diferencial no lineal que captura la característica voltaje – corriente del arco eléctrico. Las fluctuaciones de voltaje se generan con un circuito de caos que modula la amplitud del voltaje del arco eléctrico. El segundo modelo está basado en las relaciones empíricas entre la longitud de arco, la tensión y la corriente a través del arco. Las fluctuaciones de voltaje se obtienen agregando una señal aleatoria a la longitud del arco eléctrico. Ambos modelos son implementados en PSCADTM. Resultados: Los resultados de ambos modelos son comparados con mediciones reales tomadas en la etapa más crítica de la operación del horno, y muestran que el modelo basado en la conservación de la potencia presenta un menor error medio cuadrático promedio en los voltajes y corrientes de 5,6 V y 1.7 kA frente a 27,2 V y 3.38 kA obtenidos con el segundo modelo. Conclusiones: Ambos modelos consideran la no linealidad y comportamiento aleatorio que exhibe este tipo de carga, validando su inclusión en modelos computacionales de sistemas eléctricos de potencia.

Modelos reológicos aplicados a masas de trigo y maíz

OpenAIRE

Rodriguez Sandoval, Eduardo; Fernández Quintero, Alejandro; Ayala Aponte, Alfredo

2005-01-01

Los modelos reológicos de un alimento procesado permiten simular la respuesta del material a un esfuerzo o deformación aplicada, al igual que predecir el comportamiento del material de acuerdo a su composición y su forma de preparación. Su aplicación se puede llevar a cabo cuando se tienen datos experimentales expresados en unidades fundamentales. Este artículo describe dos modelos reológicos empleados en el estudio de masas de trigo y maíz, el modelo extensional biaxial y el modelo dinámico ...

Modelos reológicos aplicados a masas de trigo y maíz

OpenAIRE

Rodríguez Sandoval, Eduardo; Fernández Quintero, Alejandro; Ayala Aponte, Alfredo

2010-01-01

Los modelos reológicos de un alimento procesado permiten simular la respuesta del material a un esfuerzo o deformación aplicada, al igual que predecir el comportamiento del material de acuerdo a su composición y su forma de preparación. Su aplicación se puede llevar a cabo cuando se tienen datos experimentales expresados en unidades fundamentales. Este artIculo describe dos modelos reológicos empleados en el estudio de masas de trigo y maIz, el modelo extensional biaxial y el modelo dinámico...

EL MODELO DE REGRESIÓN LOGÍSTICA PARA EL CASO EN QUE LA VARIABLE DE RESPUESTA PUEDE ASUMIR UNO DE TRES NIVELES: ESTIMACIONES, PRUEBAS DE HIPÓTESIS Y SELECCIÓN DE MODELOS

Directory of Open Access Journals (Sweden)

Humberto Llinás Solano

2017-04-01

Full Text Available Este tratado sigue el siguiente esquema: se presenta, primero el vector score y la matriz de información de los modelos logístico y saturado multinomial con tres posibles niveles de respuesta a partir de la primera y segunda derivada de la función de verosimilitud respecto a los parámetros de los modelos; las relaciones entre el vector score y la matriz de información; la estandarización multivariante de las variables de entrada de cada modelo; las respectivas distribuciones asintóticas; las pruebas de comparación y selección de modelos que abarcan para la variable politómica con tres niveles los modelos logístico y saturado, logístico y submodelo, logístico con el modelo nulo, y logístico con el submodelo de una variable explicativa menos.

Consideration of heat transfer performance of helium-gas/water coolers in HENDEL

International Nuclear Information System (INIS)

Inagaki, Yoshiyuki; Miyamoto, Yoshiaki

1986-10-01

The helium engineering loop (HENDEL) has four helium-gas/water coolers, where the cooling water flows in the tubes and the helium gas flows on the shell side. Their cooling performance depends on mainly the heat transfer of helium gas on the shell side. This report describes the operational data of the coolers and the consideration of the heat transfer performance which is important for the design of coolers. It becomes clear that Donohue's equation is close to the operational data and conservative for the segmental baffle type cooler and preduction by Fishenden-Saunders or Zukauskas' equation is conservation for the step-up baffle type cooler. (author)

A new method to calculate pressure drop and shell-side heat transfer coefficient in a shell-and-tube heat exchanger

International Nuclear Information System (INIS)

Baptista Filho, B.D.; Konuk, A.A.

1981-01-01

A new method to calculate pressure drop (Δp) and shell-side heat transfer coefficient (h sub(c)) in a shell-and-tube heat exchanger with segmental baffles is presented. The method is based on the solution of the equations of conservation of mass and momentum between two baffles. The calculated distributions of pressure and velocities given respectively, Δp and h sub(c). The values of Δp and h sub(c) are correlated for a given geometry whit the shell side fluid properties and flow rate. The calculated and experimental results agree very well for a U-Tube heat exchanger. (Author) [pt

Estudio comparativo de los modelos de propagación de canal inalámbrico

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Reinier Alonso Quintana

2013-04-01

Full Text Available Los modelos de propagación del canal inalámbrico resultan de gran importancia en el diseño de redes y sistemas, dada su gran diversidad, es necesario determinar los modelos más eficaces para cada entorno. En este artículo se evalúa el desempeño de una selección de modelos de propagación en ambientes urbanos y suburbanos. Se determina el impacto de la altura de la estación base sobre las predicciones de los modelos, destacándose la sensibilidad de aquellos que incluyen información detallada del entorno en su formulación. Finalmente, son comparadas las predicciones de los modelos evaluados con mediciones reales, resultando el Hata y el Walfisch-Ikegami como los modelos más precisos para su aplicabilidad en estos entornos.

Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

KAUST Repository

Pathak, Nirenkumar; Li, Sheng; Kim, Youngjin; Chekli, Laura; Phuntsho, Sherub; Jang, Am; Ghaffour, NorEddine; Leiknes, TorOve; Shon, Ho Kyong

2018-01-01

A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxic–anoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100 %) due to its higher molar mass and positive charge. With inorganic DS caffeine (94-100 %) revealed highest removal followed by atenolol (89-96 %) and atrazine (16-40 %) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.

Assessing the removal of organic micropollutants by a novel baffled osmotic membrane bioreactor-microfiltration hybrid system

KAUST Repository

Pathak, Nirenkumar

2018-04-14

A novel approach was employed to study removal of organic micropollutants (OMPs) in a baffled osmotic membrane bioreactor-microfiltration (OMBR-MF) hybrid system under oxic–anoxic conditions. The performance of OMBR-MF system was examined employing three different draw solutes (DS), and three model OMPs. The highest forward osmosis (FO) membrane rejection was attained with atenolol (100 %) due to its higher molar mass and positive charge. With inorganic DS caffeine (94-100 %) revealed highest removal followed by atenolol (89-96 %) and atrazine (16-40 %) respectively. All three OMPs exhibited higher removal with organic DS as compared to inorganic DS. Significant anoxic removal was observed for atrazine under very different redox conditions with extended anoxic cycle time. This can be linked with possible development of different microbial consortia responsible for diverse enzymes secretion. Overall, the OMBR-MF process showed effective removal of total organic carbon (98%) and nutrients (phosphate 97% and total nitrogen 85%), respectively.

Um modelo alternativo para a quantificação de multiprodutos em árvores individuais

OpenAIRE

Soares,Thelma Shirlen; Leite,Helio Garcia; Vale,Antônio Bartolomeu do

2004-01-01

Neste estudo foram conduzidos testes preliminares com o objetivo de avaliar um modelo de taper, proposto a partir da adaptação dos modelos desenvolvidos por Ormerod (1973) e Turnbull (1979), caracterizados pela sua simplicidade e facilidade de ajuste. Em comparação com modelos já consagrados, observou-se que o modelo alternativo apresentou consistência nos ajustes realizados. Portanto, pode-se concluir que o modelo apresentado é recomendável para a quantificação de multiprodutos de árvores in...

Estimacion de modelos de volatilidad estocástica en series de rendimientos bursátiles

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Calvo Martín, Meri Emilia

2005-01-01

Full Text Available Las series temporales de alta frecuencia observadas en los mercados financieros y cambiarios se caracterizan por ser asimétricas, leptocúrticas, agrupamiento de la volatilidad, mostrar una elevada persistencia en volatilidad, correlaciones en los cuadrados, efecto leverage, etc. Estas características son las que se conoce en la literatura econométrica como hechos estilizados. Para recoger estas características de las series temporales se han planteado modelos no lineales, entre los que se pueden destacar básicamente dos tipos: por un lado, los modelos ARCH y GARCH y todas sus posibles variantes y por otro lado, los modelos de volatilidad estocástica. Estos modelos se diferencian entre sí en la forma de modelizar la volatilidad, así el primer tipo de modelos se caracteriza porque la varianza condicional depende de las observaciones pasadas de la serie (modelos ARCH y de sus propios valores pasados (modelos GARCH, mientras que en los modelos de volatilidad estocástica la volatilidad es función de un proceso estocástico no observable. En este trabajo, vamos a analizar los distintos resultados obtenidos de la estimación de los dos tipos de modelos anteriormente propuestos, aplicados a series de rendimientos de índices bursátiles.

Incorporando graus de liberdade de rotação em modelo clássico em acidente de trânsito – modelo de espalhamento entre dois veículos

Directory of Open Access Journals (Sweden)

Flávio Henrique Severino Oliveira Vieira

2011-09-01

Full Text Available Neste trabalho é apresentado de modo detalhado um modelo simples onde é introduzido o grau de liberdade de rotação no espalhamento de dois veículos, sendo o modelo clássico apresentado em detalhes na referência [3]. São adotadas aqui as mesmas aproximações não rigorosas quanto a dissipação de energia e momento no vértice de interação entre os veículos, sendo este efeito desconsiderado. O objetivo principal é o estabelecimento de um modelo com a incorporação de graus de liberdade de rotação para comparação do seu efeito frente ao modelo de “pontos materiais” usualmente empregado. Tal modelo aqui apresentado encontra-se em trabalho de formação de curso da ACADEPOL São Paulo do ano de 2006 de autoria do presente.

COMUNICACIÓN EN SALUD: CONCEPTOS Y MODELOS TEORICOS

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Iván Ríos Hernández

2011-01-01

Full Text Available A través de este artículo de revisión de tema se analiza el concepto comunicación en salud y algunas de las definiciones esbozadas hasta el momento por organismos internacionales y expertos del tema. Se presenta una mirada crítica y reflexiva sobre algunos de los principales modelos teóricos desarrollados en el campo de la comunicación en salud. Se esboza un análisis del paradigma de la Comunicación para el Cambio Social y se compara con las otras teorías y modelos de comunicación en salud discutidos en el escrito. Luego del análisis reflexivo se concluye que el apoderamiento de las comunidades en las estrategias de prevención de enfermedades, representa un reto para los estudios concernientes a las teorías y modelos que tratan de explicar de forma simplificada los elementos inmersos en un proceso de comunicación en salud.

Evaluation of Baffle Fixes Film up Flow Sludge Blanket Filtration (BFUSBF) System in Treatment of Wastewaters from Phenol and 2,4-Dinitrophenol Using Daphnia Magna Bioassay

OpenAIRE

Mohammad Javad Ghannadzadeh; Ahmad Jonidi Jafari; Abbas Rezaee; Fatemeh Eftekharian; Ali Koolivand

2016-01-01

Background: Phenol and nitrophenol are common compounds found in different types of industrial wastewater known as serious threats to human health and natural environment. In this study, Daphnia magna was used to evaluate the effectiveness of "baffle fixes film up flow sludge blanket filtration" (BFUSBF) system in elimination of phenolic compounds from water. Methods: D. magna cultures were used as toxicity index of phenol and 2,4-DNP mixtures after treatment by a pilot BFUSBF system which...

CALIDAD Y RESPONSABILIDAD SOCIAL EMPRESARIAL: UN MODELO DE CAUSALIDAD

Directory of Open Access Journals (Sweden)

AMPARO ZAPATA-GÓMEZ

2013-01-01

Full Text Available El presente artículo desarrolla un modelo basado en el uso de funciones matemáticas y estadísticas, que identifica las relaciones de causalidad entre las dimensiones de la calidad y las dimensiones de la responsabilidad social empresarial. La investigación partió del desarrollo de un instrumento que permite evaluar, con suficiente fiabilidad y validez, la relación entre la calidad, los procesos, los clientes y la innovación. Posteriormente, se formuló un modelo causal según las dimensiones planteadas; los resultados permitieron establecer que existe una correlación fuertemente positiva entre la calidad y la responsabilidad social. Adicionalmente, el modelo brinda información para desarrollar otras aplicaciones teóricas a partir de datos empíricos.

Transición de fase para modelos diluidos con espines discretos y medidas de Young-Gibbs para el modelo de Ising

OpenAIRE

Soprano Loto, Nahuel

2015-01-01

Esta tesis contiene dos partes con un tema en común: en cada una de ellas, estudiamos diferentes modelos de mecánica estadística. En la primera parte, estudiamos modelos diluidos de vecinos próximos con espacio de espines finito, donde el grafo subyacente es un subgrafo aleatorio del reticulado d-dimensional. Más precisamente, proporcionamos condiciones suficientes y necesarias para que ocurra co-existencia de fases mediante técnicas de aglomerado aleatorio. En la segunda parte, estudiamos un...

Modelo de PCP para pequenas empresas do setor alimentício

OpenAIRE

Carvalho, Vianey Santos de; Pacheco, Diego Augusto de Jesus

2015-01-01

O principal objetivo desta pesquisa foi desenvolver e implantar um modelo de Planejamento e Controle da Produção no contexto das pequenas empresas do setor alimentício brasileiro. Os principais procedimentos metodológicos adotados foram a abordagem quantitativa e qualitativa e o estudo de caso para avaliar o desempenho do modelo. O estudo de caso contemplou o desenvolvimento de um modelo específico para o setor alimentício e a aplicação de atividades de PCP de acordo com as necessidades da pe...

Estandarización de un modelo para inducir obesidad en ratas

OpenAIRE

Gipsis Suárez Román; Alfredo Jesús Perera Calderín; Sonia Clapés Hernández; Tammy Fernández Romero; Esteban Egaña Morales

2013-01-01

Fundamento: La obesidad es un factor de riesgo para múltiples enfermedades. Existen diversos modelos en ratas para inducir obesidad. Los modelos genéticos y la obesidad inducida por la dieta son costosos. Dentro de los modelos hipotalámicos de obesidad está el que se logra mediante la administración de glutamato monosódico en período neonatal. Esta sustancia no es costosa y produce las alteraciones metabólicas más importantes que se ven en la obesidad humana. Objetivo: seleccionar un esquema ...

Resistencias barriales al modelo empresarial de ciudad

Directory of Open Access Journals (Sweden)

Oscar Alexander Granada Ortiz

2016-05-01

Full Text Available Este texto, es un avance de la investigación Fronteras urbanas: Análisis Territorial y Crítica Política del Modelo de Ciudad en el POT Medellín”, la cual está inspirada en la inquietud que genera el pensar el Modelo de Ciudad explícito en la Política de Ordenamiento Territorial que viene ejecutando la administración municipal, debido a que esta se muestra como una nueva y regenerada forma de administrar lo público, y que pretende aparentar que se han superado los problemas que aquejan a la ciudad y sus pobladores.

Biologic treatment of wastewater from cassava flour production using vertical anaerobic baffled reactor (VABR

Directory of Open Access Journals (Sweden)

Gleyce T Correia

2008-08-01

Full Text Available The estimate cassava production in Brazil in 2007 was of 25 million tons (= 15% of the world production and most of it is used in the production of flour. During its processing, waste that can cause environmental inequality is generated, if discharged inappropriately. One of the liquid waste generated, manipueira, is characterized by its high level of organic matter. The anaerobic treatment that uses a vertical anaerobic baffled reactor (VABR inoculated with granulated sludge, is one of the ways of treating this effluent. The anaerobic biodigestion phases are separated in this kind of reactor, allowing greater stability and resistance to load shocks. The VABR was built with a width/height rate of 1:2. The pH, acidity, alkalinity, turbidity and COD removal were analyzed in 6 different regions of the reactor, which was operated with an increasing feeding from ? 2000 to ? 10000 mg COD L?¹ and HRT between 6.0 and 2.5 days. The VABR showed decreasing acidity and turbidity, an increase in alkalinity and pH, and 96% efficiency in COD removal with 3-day HRT and feeding of 3800 mg COD L?¹.

Agrupamiento de Filas y Columnas Homogéneas en Modelos de Correspondencia

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Marinelli Claudia

2011-04-01

Full Text Available Goodman (1981 propone criterios de homogeneidad y estructura para Modelos de Asociación que permiten determinar si pueden agruparse ciertas filas o columnas en una tabla de contingencia. Luego muestra las relaciones entre scores canónicos y los scores correspondientes a Modelos de Asociación. Gilula (1986 desarrolla resultados de agrupamiento sugeridos por los scores canónicos asociados en una tabla de contingencia bajo un modelo de Correlación Canónica RC. Por otra parte, el Análisis de Correspondencia se puede ver como una reparametrización del Modelo de Correlación Canónica en virtud de la propuesta de Goodman (1986 y van der Heijden et al (1994.

O desenvolvimento de um modelo de assistência continua ao parto Desarrollo de un modelo de asistencia continua en el parto Development of a delivery continued care model

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Ana Cláudia Silveira Lambert

2010-07-01

Full Text Available Objetivo. Descrever as experiências das enfermeiras obstétricas relacionadas com o desenvolvimento de um modelo de assistência ao parto. Metodologia. investigação do tipo estudo de caso. Analisaramse as declarações de quatro enfermeiras obstétricas, que desenvolveram o modelo de assistência ao parto proposto pelo Hospital Universitário da Universidade de São Paulo. A informação obtida se analisou de modo indutivo e interpretativo. Resultados. das narrativas surgiram quatro categorias descritivas: a a convivência com o sentimento de ambivalência, b o trabalho com facilidades e dificuldades com a adoção do novo modelo, c as mudanças no conceito da assistência ao parto, e d os benefícios proporcionados pelo modelo. As enfermeiras reconhecem a viabilidade do modelo, mas sua implementação definitiva na instituição depende das mudanças nas diretrizes filosóficas e gerenciais relacionadas com a assistência ao parto e do compromisso dos profissionais. Conclusão. Reconheceramse os diversos aspectos envolvidos na implementação do modelo de atendimento no parto.Objetivo. Describir las experiencias de las enfermeras obstétricas relacionadas con el desarrollo de un modelo de asistencia al parto. Metodología. Investigación del tipo estudio de caso. Se analizaron las declaraciones de cuatro enfermeras obstétricas, que desarrollaron el modelo de asistencia al parto propuesto por el Hospital Universitario de la Universidad de São Paulo. La información obtenida se analizó de modo inductivo e interpretativo. Resultados. De las narrativas surgieron cuatro categorías descriptivas: a la convivencia con el sentimiento de ambivalencia, b el trabajo con facilidades y dificultades con la adopción del nuevo modelo, c los cambios en el concepto de la asistencia al parto, y d los beneficios proporcionados por el modelo. Las enfermeras reconocen la viabilidad del modelo, pero su implementación definitiva en la institución depende de

Brookhaven segment interconnect

International Nuclear Information System (INIS)

Morse, W.M.; Benenson, G.; Leipuner, L.B.

1983-01-01

We have performed a high energy physics experiment using a multisegment Brookhaven FASTBUS system. The system was composed of three crate segments and two cable segments. We discuss the segment interconnect module which permits communication between the various segments

MODELO AUTORREGRESIVO BILINEAL APLICADO A LA PREDICCIÓN MENSUAL DE CAUDALES EN COLOMBIA

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Juan David Cadavid

2013-12-01

Full Text Available Se aplica un modelo estocástico bilineal, el cual inicialmente es propuesto para análisis de retornos financieros y otros sistemas complejos combinando la alta no linealidad y multiplicidad del ruido. Este modelo, por su carácter aleatorio, no tiene componente determinística que permita considerar la persistencia de los caudales en una aplicación a la Hidrología. Por lo tanto, se propone el acoplamiento entre la parte determinística de un modelo autorregresivo de orden 2 y el modelo estocástico bilineal como componente aleatorio, y se obtiene un modelo autorregresivo bilineal (MAB. El MAB se empleó para la predicción de caudales en ventanas de 3, 6 y 12 meses en 12 ríos de Colombia de diferentes regiones del país. El MAB tiene una estructura simple y muestra una mejora sustancial en la disminución de los errores para los caudales máximos y mínimos en el período de validación respecto de los modelos estocásticos tradicionales.

Active Segmentation.

Science.gov (United States)

Mishra, Ajay; Aloimonos, Yiannis

2009-01-01

The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary.We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach.

Aproximación a un modelo de aprovisionamiento de servicios convergentes

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Julián Andrés Caicedo

2014-12-01

Full Text Available El aprovisionamiento de servicios de telecomunicaciones ha cambiado notablemente en los últimos 30 años; se ha pasado de modelos estáticos, rígidos y controlados por un solo actor de negocio a modelos dinámicos, flexibles, con múltiples actores en la cadena de valor y orientados a los usuarios finales. Diferentes enfoques han planteado modelos de aprovisionamiento que cumplan requerimientos específicos a los operadores de telecomunicaciones. Sin embargo, aún no están claros los procesos principales que deben desarrollarse en cada fase del ciclo de vida del servicio para que permitan una integración efectiva entre diferentes modelos de aprovisionamiento. En este artículo se presenta una aproximación al modelo inicial de aprovisionamiento de servicios convergentes, el cual abstrae los principales procesos dentro de las fases de diseño, despliegue y operación del servicio. De igual manera, se presenta un piloto funcional que ejecuta de manera automática el proceso de despliegue inicial en un entorno convergente con base en los procesos definidos en esta fase. Finalmente, el mecanismo es sometido a una prueba de escalabilidad para evaluar su desempeño.

ANÁLISIS DE LA INESTABILIDAD DE TURING EN MODELOS BIOLÓGICOS

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JUAN VANEGAS

2009-01-01

Full Text Available El análisis matemático de modelos biológicos descritos por ecuaciones de reacción difusión da lugar al concepto de inestabilidad de Turing. En este artículo se analiza este concepto y el espacio matemático en donde tiene lugar, conocido como espacio de Turing. El objetivo es establecer la relación entre el conjunto de parámetros que definen la presencia de patrones espacio-temporales en un sistema de reacción difusión. Estos parámetros son validados mediante la implementación numérica por el método de los elementos finitos en 1D y 2D de dos modelos conocidos: el modelo de Schnakenberg y el modelo de glucólisis. Los resultados demuestran que los parámetros obtenidos mediante el análisis matemático cumplen las restricciones de Turing y permiten la formación de patrones espacio-temporales. Se concluye que el análisis matemático de estabilidad es una herramienta útil para la obtención de parámetros desconocidos en modelos que usualmente requieren de ajustes mediante experimentación numérica.

BALANCED SCORECARD PARA EMPRENDEDORES: DESDE EL MODELO CANVAS AL CUADRO DE MANDO INTEGRAL

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JOSÉ MANUEL SÁNCHEZ VÁZQUEZ

2016-01-01

Full Text Available El Cuadro de Mando Integral (BSC y el modelo Canvas pueden enlazarse como herramientas complementarias para los emprendedores. La primera desarrolla objetivos y medidas operativas en cuatro perspectivas principales para alcanzar la misión y estrategia. La segunda ha supuesto una (re-evolución en la generación de modelos de negocio, estableciendo nueve apartados que reflejan su lógica. En el artículo se desarrolla un modelo de trabajo que, partiendo de la necesidad de dispo - ner de un BSC, relaciona su diseño con la información recogida previamente en el modelo Canvas, señalando su mutua necesidad.

Modelos animais de aneurisma de aorta Animal models of aortic aneurysm

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Rodrigo Argenta

2009-06-01

Full Text Available Os modelos experimentais em animais vêm sendo utilizados em cirurgia vascular há décadas. O desenvolvimento de novas técnicas para tratamento endovascular dos aneurismas requer a criação de bons modelos experimentais para testar esses dispositivos e estudar seu impacto sobre a progressão da doença. Este artigo tem por objetivo revisar os modelos de aneurisma arterial descritos atualmente. Entre os diversos modelos descritos, nenhum reúne todas as características de um modelo ideal de aneurisma. Os modelos em animais de grande porte são adequados para treino, estudo de alterações em parâmetros fisiológicos durante e após a liberação dos dispositivos e integração do mesmo à parede do vaso. Algumas desvantagens significantes incluem dificuldade do manejo, alto custo, difícil manutenção e regulamentações legais, dificultando a disponibilidade de diversas espécies animais. Modelos em animais menores, como os coelhos e camundongos, embora sejam menos caros e de fácil obtenção, não são adequados para estudos de técnicas endovasculares pelas pequenas dimensões de seus vasos. Nenhum modelo descrito até o momento consegue reproduzir todas as características dos aneurismas observados em humanos. Modelos disponíveis são descritos nesta revisão, e suas vantagens e desvantagens são discutidas.Experimental animal models have been used in vascular surgery for decades. The development of new interventional techniques in the endovascular treatment of aneurysms requires the creation of good experimental models to test these devices and study their impact on disease progression. The aim of this article was to review arterial aneurysm models currently available. Several distinct models have been described but none of them satisfies all the requirements of an ideal aneurysm model. Large animal models are appropriate for training, study of alterations in physiological parameters during and after device delivery, and integration

GeoSegmenter: A statistically learned Chinese word segmenter for the geoscience domain

Science.gov (United States)

Huang, Lan; Du, Youfu; Chen, Gongyang

2015-03-01

Unlike English, the Chinese language has no space between words. Segmenting texts into words, known as the Chinese word segmentation (CWS) problem, thus becomes a fundamental issue for processing Chinese documents and the first step in many text mining applications, including information retrieval, machine translation and knowledge acquisition. However, for the geoscience subject domain, the CWS problem remains unsolved. Although a generic segmenter can be applied to process geoscience documents, they lack the domain specific knowledge and consequently their segmentation accuracy drops dramatically. This motivated us to develop a segmenter specifically for the geoscience subject domain: the GeoSegmenter. We first proposed a generic two-step framework for domain specific CWS. Following this framework, we built GeoSegmenter using conditional random fields, a principled statistical framework for sequence learning. Specifically, GeoSegmenter first identifies general terms by using a generic baseline segmenter. Then it recognises geoscience terms by learning and applying a model that can transform the initial segmentation into the goal segmentation. Empirical experimental results on geoscience documents and benchmark datasets showed that GeoSegmenter could effectively recognise both geoscience terms and general terms.

Modelo de benchmarking de la cadena de abastecimiento para pymes manufactureras.

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Alfredo Beltrán Amador

2002-01-01

Full Text Available El modelo de benchmarking de la cadena de abastecimiento para Pymes manufactureras representa una guía para el mejoramiento de los procesos logísticos de una Pyme dedicada a la producción. En el presente artículo se muestra tanto el desarrollo del modelo como los principales resultados de su implementación en una muestra de empresas del Prodes (Programa de Desarrollo Sectorial de alimentos de Acopi, de la ciudad de Cali. Con base en los resultados de este estudio de aplicación demostrativa y de prueba, se establecen pautas para futuras investigaciones y aplicaciones del modelo en otros sectores. Este modelo ha sido desarrollado con base en los hallazgos del estudio titulado «Propuesta para el desarrollo de un sistema logístico integral para Pymes», realizado por los autores, como opción de grado para el título de Maestría en Administración, en convenio con la Universidad de Tulane.

Modelos epidémicos con control por vacunación

OpenAIRE

Saralegui Vallejo, Unai

2016-01-01

Existen diferentes tipos de modelos epidémicos no lineales en los que las dinámicas de las sub-poblaciones ( susceptibles, infectados , recobrados , vacunados etc. ) están acopladas. La vacunación puede interpretatrse como un control cuyo objetivo es eliminar la infección. Se estudian estos modelos matemáticamente, para despues comprobar los resultados obtenidos mediante simulaciones.

Modelos de serviços hospitalares para casos agudos em idosos

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Coelho Filho João Macedo

2000-01-01

Full Text Available Embora a atenção ao idoso seja uma prioridade emergente no Brasil, pouca ênfase tem sido dada a modelos de organização de serviços hospitalares para pacientes geriátricos. São revisados modelos de serviços hospitalares para admissão e manuseio de casos agudos em idosos, com ênfase na discussão sobre o papel e o posicionamento da medicina geriátrica (incluindo sua interface com especialidades e com a clínica médica no âmbito da atenção hospitalar. Foi realizada pesquisa na base de dados Medline (1989-1999, bem como nos principais livros-texto de geriatria e de gerontologia, buscando identificar descrições de serviços hospitalares para cuidado agudo de pacientes idosos. As características dos modelos identificados foram compiladas e descritas à luz de sua adequação à realidade dos serviços de saúde no Brasil. Exemplos de intervenções em geriatria, com efetividade demonstrada através de revisões sistemáticas, foram também citadas. Os modelos mais freqüentemente relatados foram cuidado prolongado, tradicional, baseado na idade cronológica, não especializado e integrado. Adaptações e variantes de alguns desses modelos foram freqüentemente relatadas, assim como seu impacto potencial na efetividade do cuidado geriátrico. Evidências sobre o melhor modelo a seguir não foram identificadas, mas aqueles modelos favorecendo a integração da geriatria com a clínica geral pareceram mais adequados à nossa realidade. Ressalta a necessidade de reestruturação de serviços de saúde para responder às novas demandas que surgem com o envelhecimento da população, bem como do delineamento de serviços hospitalares para casos agudos, importantes para a efetividade do cuidado geriátrico e que devem ser objeto de maior debate e pesquisa no Brasil.

MODELO INTERACTIVO FUNCIONAL DEL SISTEMA DE TELEVISIÓN

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Cesar Augusto Ramirez Corzo

2011-01-01

Full Text Available El siguiente artículo presenta el modelo comunicativo interactivo mediante el cual se describe, se analiza y se demuestra la incapacidad del sistema de televisión en Colombia para garantizar la protección de los menores de edad frente a los contenidos televisivos, destacándose tres subsistemas, el industrial, el humano y el legal. El modelo permite visualizar cómo funcionan y se integran los actores, cuáles son su propósitos, y el impacto que generan en el público receptor. El marco teórico se centra en el Interaccionismo Simbólico y en el estructural funcionalismo, para demostrar como el menor de edad queda totalmente expuesto a unos intereses económicos de la industria, sin suficiente protección del sistema legal, produciendo graves consecuencias en su dimensión espiritual, personal y social. El modelo comunicativo interactivo se convierte en un referente de análisis para investigaciones sociales que contemplen la influencia de los contenidos culturales en el individuo y en la sociedad.

Single-segment and double-segment INTACS for post-LASIK ectasia.

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Hassan Hashemi

2014-09-01

Full Text Available The objective of the present study was to compare single segment and double segment INTACS rings in the treatment of post-LASIK ectasia. In this interventional study, 26 eyes with post-LASIK ectasia were assessed. Ectasia was defined as progressive myopia regardless of astigmatism, along with topographic evidence of inferior steepening of the cornea after LASIK. We excluded those with a history of intraocular surgery, certain eye conditions, and immune disorders, as well as monocular, pregnant and lactating patients. A total of 11 eyes had double ring and 15 eyes had single ring implantation. Visual and refractive outcomes were compared with preoperative values based on the number of implanted INTACS rings. Pre and postoperative spherical equivalent were -3.92 and -2.29 diopter (P=0.007. The spherical equivalent decreased by 1 ± 3.2 diopter in the single-segment group and 2.56 ± 1.58 diopter in the double-segment group (P=0.165. Mean preoperative astigmatism was 2.38 ± 1.93 diopter which decreased to 2.14 ± 1.1 diopter after surgery (P=0.508; 0.87 ± 1.98 diopter decrease in the single-segment group and 0.67 ± 1.2 diopter increase in the double-segment group (P=0.025. Nineteen patients (75% gained one or two lines, and only three, who were all in the double-segment group, lost one or two lines of best corrected visual acuity. The spherical equivalent and vision significantly decreased in all patients. In these post-LASIK ectasia patients, the spherical equivalent was corrected better with two segments compared to single segment implantation; nonetheless, the level of astigmatism in the single-segment group was significantly better than that in the double-segment group.

Optical Design of the STAR-X Telescope

Science.gov (United States)

Saha, Timo T.; Zhang, William W.; McClelland, Ryan S.

2017-01-01

Top-level science goals of the Survey and Time-domain Astrophysical Research eXplorer (STAR-X) include: investigations of most violent explosions in the universe, study of growth of black holes across cosmic time and mass scale, and measure how structure formation heats majority of baryons in the universe. To meet these goals, the field-of-view of the telescope should be about 1 square-degree, the angular resolution should be 5 arc-seconds or below across large part of the field-of-view. The on-axis effective area at 1 KeV should be about 2,000 sq cm. Payload cost and launch considerations limit the outer diameter, focal length, and mass to 1.3 meters, 5 meters, and 250 kilograms, respectively. Telescope design is based on a segmented meta-shell approach we have developed at Goddard Space Flight Center for the STAR-X telescope. The telescope shells are divided into 30-degree segments. Individual telescopes and meta-shells are nested inside each other to meet the effective area requirements in 0.5 - 6.0 KeV range. We consider Wolter-Schwarzschild, and Modified-Wolter-Schwarzschild telescope designs as basic building blocks of the nested STAR-X telescope. These designs offer an excellent resolution over a large field of views. Nested telescopes are vulnerable to stray light problems. We have designed a multi-component baffle system to eliminate direct and single-reflection light paths inside the telescopes. Large number of internal and external baffle vane structures are required to prevent stray rays from reaching the focal plane. We have developed a simple ray-trace based tool to determine the dimensions and locations of the baffles. In this paper, we present the results of our trade studies, baffle design studies, and optical performance analyses of the STAR-X telescope.

Modelo de administración de inventarios para una empresa de telecomunicaciones

OpenAIRE

Recalde Suárez, Daniel Leonardo

2015-01-01

Esta tesis de Maestría propone un Modelo de Administración de Inventarios para una empresa del sector de las Telecomunicaciones. Se basa en identificar un Modelo de acuerdo a las características del Inventario según (Heizer Render, 2009). El resultado de este trabajo es definir la Administración del Inventario cumpliendo con los requerimientos para este tipo de empresas; porque utilizan los inventarios para impulsar de alguna manera el consumo de los servicios, el Modelo de Administración pe...

Un Modelo Holístico de Competencia Docente para el Mundo Digital

OpenAIRE

Esteve, Francesc; Castañeda, Linda; Adell Segura, Jordi

2018-01-01

En este trabajo se presenta un modelo de competencia docente para el mundo digital que pretende superar algunas de las principales limitaciones de modelos previos, especialmente un concepto de competencia restrictivo, una visión de la acción docente reducida al aula y una perspectiva instrumentalista de la tecnología. El modelo, pensado para la enseñanza básica, describe a un docente generador de prácticas y contenidos pedagógicos digitales, práctico-reflexivo aumentad...

Capacidad Predictiva de Modelos de Insolvencia con Base en Números Contables y Datos Descriptivos

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Júlio Orestes da Silva

2012-01-01

Full Text Available En el Brasil la pesquisa sobre modelos de previsión de insolvencia se inició en la década de 1970, siendo que lamayor parte de los trabajos hizo uso del Análisis Discriminante como herramienta estadística del modelo. En losúltimos años, se buscó verificar si es posible prever la insolvencia de las empresas utilizando datos descriptivoscontenidos en los informes de las organizaciones. Así, este estudio tiene como objetivo verificar la capacidad dealgunos modelos de previsión de insolvencia en prever la discontinuidad de empresas brasileñas que decretaron quiebra. La pesquisa se caracteriza como descriptiva y posee abordaje cuantitativo, realizado por medio de pesquisadocumental. La muestra totalizó 13 empresas que decretaron quiebra entre los años de 1997 y 2003. Los resultadosindican que la mayoría de los modelos de previsión de quiebra testados presentó resultados elevados deprevisiones correctas. Los modelos de previsión de discontinuidad con base en informes descriptivos obtuvieronen media más previsiones asertivas en relación a la capacidad de prever la quiebra de las empresas. Esos descubrimientosdemuestran que, a pesar de que algunas pesquisas apunten hacia la falta de validez de predictores creadosen realidades empresariales diferentes, algunos modelos todavía poseen buena capacidad de previsión de insolvencia.Se concluye que tanto los modelos de previsión de insolvencia con base en números contables en relación alos modelos que se utilizan datos de informes descriptivos pueden prever la discontinuidad de las organizaciones.Por fin, se puede inferir que la mayoría de los modelos de previsión de quiebra que hacen uso de números contablespueden ser funcionales y capaces de prever la discontinuidad de las organizaciones.

Construindo um modelo de sistema de cuidados Construyendo un modelo de sistema de cuidados Developing an explanatory theoretical model of system of care

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Alacoque Lorenzini Erdmann

2007-06-01

Full Text Available OBJETIVO: Construir um modelo teórico explicativo de Sistema de Cuidados. METODO: Estudo exploratório qualitativo apoiado nos pressupostos da Grounded Theory. Participaram do estudo 15 profissionais e os dados foram coletados por entrevista aberta. RESULTADOS: O Modelo teórico foi delimitado a partir do fenômeno Construindo o Sistema Complexo de Cuidados determinado pelas categorias: Convivendo com a dinamicidade do sistema de cuidados e Organizando o sistema de cuidados a partir de múltiplas interações. CONCLUSÃO: O modelo de sistema de cuidados apresentou-se como sistema vital e dinâmico construído a partir de redes interacionais de vários saberes do agir humano expresso pelo trabalho compartilhado, multidisciplinar e em equipe.OBJETIVO: Construir un modelo teórico explicativo de Sistema de Cuidados. MÉTODO: Se trata de un estudio cualitativo exploratorio apoyado en las premisas de la Teoría Fundamentada en los Datos. Participaron del estudio 15 profesionales. Los datos fueron recolectados por medio de una entrevista abierta. RESULTADOS: El modelo teórico se delimitó al fenómeno Construyendo el Sistema Complejo de Cuidados determinado por las categorías: Viviendo junto con la dinamicidad del sistema de cuidados y Organizando el sistema de cuidados a partir de interacciones múltiples. CONCLUSIÓN: El modelo de sistema de cuidados se presenta como un sistema vital y dinámico construido a partir de redes de interacción de conocimientos del actuar humano expresado en el trabajo conjunto, multidisciplinario y en equipo.OBJECTIVE: To develop an explanatory theoretical model of the system of care. METHOD: Grounded theory served as the conceptual framework to conduct this qualitative exploratory study. Unstructured interviews were conducted among 15 care professionals. RESULTS: The theoretical model was delimited from the phenomenon "building complex system of care" as determined by the following categories: "dealing with a

Modelo interrelacionado de decisiones

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Edwin Haramoto Nishikimoto

2002-01-01

Full Text Available Propone la implementación de un sistema interrelacionado de decisiones que permita superar los problemas que enfrentan los agentes que participan en las áreas de trabajo involucradas en la acción habitacional. Para estos describe cuatro modelos (habitacional, de decisión, de información y de alternativas habitacionales que permiten ordenar, relacionar, agrupar y jerarquizar todos los componentes del proceso habitacional

Estimativa da produtividade de café com base em um modelo agrometeorológico-espectral

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Viviane Gomes Cardoso da Rosa

2010-12-01

Full Text Available O objetivo deste trabalho foi avaliar um modelo agrometeorológico-espectral, para estimar a produtividade de cafezais. Utilizaram-se imagens do sensor MODIS e dados agrometeorológicos do modelo regional de previsão do tempo (ETA, para fornecer as variáveis de entrada para o modelo agrometeorológico-espectral da mesorregião geográfica sul/sudoeste do estado de Minas Gerais nos anos-agrícolas de 2003/2004 a 2007/2008. A variável espectral de entrada do modelo agrometeorológico-espectral, índice de área foliar (IAF, usada no cálculo da produtividade máxima, foi estimada com o índice de vegetação por diferença normalizada (NDVI, obtido de imagens MODIS. Outras variáveis de entrada no modelo foram: dados meteorológicos gerados pelo modelo ETA e a capacidade de água disponível no solo. Ao comparar a produtividade média estimada pelo modelo com a fornecida oficialmente pelo IBGE, as diferenças relativas obtidas em escala regional foram de: 0,4, 3,0, 5,3, 1,5 e 8,5% para os anos agrícolas 2003/2004, 2004/2005, 2005/2006, 2006/2007 e 2007/2008, respectivamente. O modelo agrometeorólogico-espectral, que tem como base o modelo de Doorenbos & Kassan, foi tão eficaz para estimar a produtividade dos cafezais quanto o modelo oficial do IBGE. Além disso, foi possível espacializar a quebra de produtividade e prever 80% da produtividade final na primeira quinzena de fevereiro, antes do início da colheita

Uma extensão ao modelo Schumpeteriano de Crescimento Endógeno

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Marco Flávio da Cunha Resende

2006-03-01

Full Text Available O modelo Schumpeteriano de Crescimento Endógeno considera o progresso técnico determinante fundamental do crescimento econômico. Porém, ainda não conseguiu explicar como as inovações tecnológicas são geradas. Nesse modelo, elas ocorrem aleatoriamente. Todavia, os fatos sugerem uma explicação que apresenta um componente determinístico (tendência e outro componente aleatório para o surgimento das inovações. Portanto, foi desenvolvida neste trabalho uma extensão ao modelo schumpeteriano que visa incorporar um componente determinístico das inovações, além do componente aleatório. A partir desta modificação do modelo e da simulação da trajetória da renda per capita de cinco países entre 1800 e 2000 constatou-se que esta extensão ao modelo schumpeteriano pode explicar diversos fatos da realidade que o modelo básico não explicava.In the Schumpeterian endogenous growth model, random innovations (technical progress are the main element that explains economic growth. Empirical analyses suggest there are two variables that explain the introduction of innovations: a randomly variable and a deterministic trend. In this paper we add a deterministic variable to the basic Schumpeterian growth model. The introduction of a determinist variable improves the basic model. The new model reproduces several styled facts, which are shown in simulations.

MODELO DE NEGOCIO PARA EMPRESAS RECICLADORAS DE LLANTAS

OpenAIRE

Sanchéz Santiago, Esther

2015-01-01

El objetivo de esta investigación es diseñar un modelo de negocio sustentable que aproveche las oportunidades de mercado en la industria del reciclaje de llantas. El supuesto teórico que guió la investigación afirma que una empresa es sustentable y competitiva en función de su modelo de negocio basado en la creación de valor, su compromiso con el desarrollo sustentable, e incorpora: la gestión global, análisis de la competitividad, relación con los grupos de interés, impactos al medio ambient...

En busca de un modelo matemático

OpenAIRE

Barrales, Marco

2002-01-01

El objetivo de nuestra investigación fue ajustar un modelo matemático a un problema real. Específicamente centramos nuestra atención en determinar un modelo matemático referente al aprendizaje de una rata de laboratorio en resolver un laberinto, es decir controlamos el tiempo que invierte la rata en completar el recorrido del laberinto y el número de veces que se repetía la experiencia. Después de aplicar la interpolación Lagrangeana el comportamiento de las ratas se ajustó a una rama de una ...

O modelo de negócio do Rock in Rio: uma perspetiva exploratória

OpenAIRE

Ribeiro, Tatiana Dinis

2015-01-01

Tema: Modelo de Negócio e Criação de Valor Partilhado. Âmbito: Construção do modelo de negócio do Rock in Rio. O conceito da criação de valor partilhado é integrada nesta dissertação para compreensão da abordagem da sustentabilidade do Rock in Rio. Objetivos: O objetivo principal deste trabalho é a construção do modelo de negócio do Rock in Rio com base no modelo canvas. Os objetivos secundários são análise do funcionamento do modelo de negócio, verificar de existência de políticas de c...

Modelos de supervivencia adecuados para análisis actuariales de mortalidad.

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Medina lópez, Ana

2003-01-01

Full Text Available En el seguro de vida, se destacará el interés de los denominados modelos o funciones de supervivencia como instrumentos imprescindibles en distintas fases del análisis de mortalidad. El estudio se adaptará a los mejores datos reales disponibles en las aseguradoras respecto de la población objetivo (población asegurable: datos de pólizas que evitan sesgos derivados del uso de tablas de población general. Se analizará la utilidad de los modelos de supervivencia actuarial a tres niveles. En primer lugar, se mostrará la necesidad de utilizar hipótesis de mortalidad intraintervalo para estimar las probabilidades anuales de muerte que permitan obtener un modelo tabular. En segundo lugar, los modelos se emplearán en la denominada graduación paramétrica para mejorar las estimaciones iniciales incorporando información sobre relaciones existentes en el conjunto de estimaciones y sobre creencias previas a las observaciones. En tercer lugar, nuevos modelos serán los instrumentos que proyecten el fenómeno de la mortalidad a futuro según la dinamicidad del colectivo estudiado respecto a la mortalidad. Se presentará una visión actual de las posibilidades existentes, valorando las alternativas y trabajos empíricos ya realizados, y ofreciendo nuevas posibilidades.

Dos enfoques no abordados en los modelos de calidad: CMM y SPICE.

Directory of Open Access Journals (Sweden)

Yudith Rodríguez Pérez

2006-07-01

Full Text Available Muchas organizaciones de software tienden a resolver sus problemas de calidad institucionalizando sus procesos a través de la certificación de un modelo de calidad, sin tener en cuenta que en estos modelos no se abordan aspectos tan importantes en la vida de una organización como son la gestión de los recursos humanos y la gestión de comercialización. Con el objetivo de señalar cuales son las deficiencias de los modelos SPICE y CMM se desarrolla este trabajo.

A la búsqueda de un modelo integrado de Orientación

OpenAIRE

Rodríguez Diéguez, Antonio

2008-01-01

El artículo constituye una reflexión sobre el Modelo Comprensivo de Gysbers, sus bases teóricas, su estructura organizativa y funcional. Su fundamentación en las teorías del Desarrollo de la Carrera; el carácter de comprensividad como seña de identidad y su integración en el proceso educativo propician; por un lado establecer un paralelismo con el modelo institucional de orientación de nuestro país; por otro retomarlo como inspiración para el modelo organizativo y funcional ...

Modelo actancial. Los resortes narratológicos de la obra de Greimas

OpenAIRE

David Cruz, Janeth

2013-01-01

Este texto parte de una investigación sobre la configuración del relato en el cine de animación de la alianza Disney - Pixar y estudia el concepto del personaje desde la perspectiva del modelo actancial. Dicho modelo ha sido teorizado por Algirdas Julien Greimas y se basa en la idea de entender el personaje como un actante, es decir como un vehículo que permite el desarrollo de las acciones narrativas. Por eso se explica el alcance del modelo, sus orígenes y las actualizaciones y reinterpreta...

MODELO CINÉTICO DEL SECADO DE LA PULPA DE MANGO

Directory of Open Access Journals (Sweden)

Aquiles Ocampo

Full Text Available El propósito de este trabajo fue encontrar un modelo que permitiera predecir el tiempo de secado de la pulpa de mango (Mangifera indica con diferentes condiciones de temperatura. Se construyó un secador de laboratorio en el que se llevaron a cabo pruebas de secado a temperaturas de 55 °C, 60 °C y 65 °C, con una velocidad de aire constante de 2,0 m/s y una humedad relativa controlada de 50%. Se presenta un procedimiento sencillo que convierte el modelo de GAB en una ecuación polinomial de segundo orden. Igualmente, se muestra una manera simple aplicable a procesos similares de secado para establecer su cinética a partir de modelos simplificados de la ecuación clásica de Fick.

El Plan de la Microempresa: agotamiento de modelos ineficientes

Directory of Open Access Journals (Sweden)

Javier Pineda

1998-12-01

Full Text Available Este artículo identifica y examina tres modelos de operación de los servicios financieros y no financieros del Plan Nacional de la Microempresa en Colombia a través de su evolución histórica desde 1984 hasta 1998. Se demuestra que los tres modelos ejecutados han estado básicamente en función de garantizar mecanismos de financiación a las actividades de las ONG participantes en el Plan. En los dos primeros al colocar la capacitación como prerrequisito para el crédito y en el tercero a través de la Corporación Mixta para el Desarrollo de la Microempresa. Esta característica de los modelos, la predominancia de los intereses de las ONG, le ha generado profundas limitaciones e ineficiencias a la experiencia más significativa, en los programas de microempresa, de trabajo conjunto entre el Estado y la sociedad civil en América Latina.

Effect of substrate concentration on hydrogen production by photo-fermentation in the pilot-scale baffled bioreactor.

Science.gov (United States)

Lu, Chaoyang; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Ge, Xumeng; Xia, Chenxi; Zhao, Jia; Wang, Yi; Jing, Yanyan; Li, Yameng; Zhang, Quanguo

2018-01-01

Effect of substrate concentration on photo-fermentative hydrogen production was studied with a self-designed 4m 3 pilot-scale baffled photo-fermentative hydrogen production reactor (BPHR). The relationships between parameters, such as hydrogen production rate (HPR, mol H 2 /m 3 /d), hydrogen concentration, pH value, oxidation-reduction potential, biomass concentration (volatile suspended solids, VSS) and reducing sugar concentration, during the photo-fermentative hydrogen production process were investigated. The highest HPR of 202.64±8.83mol/m 3 /d was achieved in chamber #3 at a substrate concentration of 20g/L. Hydrogen contents were in the range of 42.19±0.94%-49.71±0.27%. HPR increased when organic loading rate was increased from 3.3 to 20g/L/d, then decreased when organic loading rate was further increased to 25g/L/d. A maximum HPR of 148.65±4.19mol/m 3 /d was obtained when organic loading rate was maintained at 20g/L/d during continuous bio-hydrogen production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of Organic Load in Communal Wastewater by using the Six Stage Anaerobic Baffle Reactor (ABR

Directory of Open Access Journals (Sweden)

Trilita Minarni Nur

2016-01-01

Full Text Available The reduction of water quality in the urban drainage is a crucial problem to overcome because it can affect the health of community. This fact encouraged the researcher to conduct the research in efforts to increase the water quality in the drainage. One of the solutions to increase the water quality in the drainage is that the domestic wastewater must be treated at first before it is flown through the drainage. Furthermore, the wastewater treatment was conducted by employing the communal wastewater processor. The research was aimed at knowing the capability of Anaerobic Baffle Reactor with the six-stage design in communal wastewater processor in efforts to decrease the organic load. This research was conducted in a laboratory scale. Meanwhile, the sort of waste used was taken from the domestic wastewater of settlement by varying its discharge and waste concentration flowing into the waste processor. Finally, the research result showed that the reduction of organic load of COD was reaching up to 92%, N was 85% and Phosphate was 50%.

Un nuevo modelo urbano

OpenAIRE

Duque Escobar, Gonzalo

2012-01-01

Urge un nuevo modelo de ciudad para para resolver la integración, abordando temas sustantivos como: el agua, las cuencas, la inversión, los servicios públicos, y la movilidad, además de la vocación de los entes territoriales y de la ciudad región como elementos clave para decidir sobre la asignación de las funciones metropolitanas y usos del suelo en el Eje Perera-Manizales

Propuesta para el manejo de restricciones en modelos de clases usando atom3

OpenAIRE

Carlos M. Zapata J.; Carlos A. Álvarez C.; Fernando Arango I.

2005-01-01

La construcción de los modelos para el desarrollo de software se ha realizado tradicionalmente con herramientas CASE. En estas herramientas los formalismos de cada modelo ya se encuentran plenamente definidos, lo que implica que no es posible agregarles nuevas restricciones. Las herramientas de Metamodelado surgieron como una manera de solución a este problema, pues poseen formalismos propios (generalmente gráficos) que permiten la expresión de diferentes modelos, incluyendo su...

Modelos para maximizar ingresos de proyectos de viviendas en el gran Concepción

Directory of Open Access Journals (Sweden)

Roberto Schovelin Surhoff

2004-07-01

Full Text Available El diseño general de viviendas incorpora características que se definen con criterios variables, por eso no siempre se obtienen buenas soluciones de mercado. En este trabajo se modeló la relación entre las características y el precio de la vivienda. Estos modelos, que son hedónicos, permiten cuantificar la incidencia de las características en el precio de las viviendas.  Para obtener mejores soluciones y maximizar el precio de  mercado del diseño del proyecto inmobiliario se debe proporcionar una combinación óptima de las características que valora el consumidor. Para diseñar departamentos de un edificio, casas de un conjunto residencial individuales o en condominio con la finalidad de maximizar su precio, requirió inicialmente confeccionar un modelo hedónico 2 para cada tipo de vivienda. Para ello se utilizó información de precios y características de viviendas, recopilada en construcciones reales desarrolladas durante los años 2002 y 2003. Los modelos de precios resultantes, obtenidos mediante regresión múltiple, resultaron los tres de tipo lineal. Todos incluyeron variables inherentes a la localización y variables relacionadas con las características de las viviendas. Con los coeficientes obtenidos por los modelos hedónicos se prepararon modelos para optimizar precios. Para el modelo de casas individuales y en condominio se busca maximizar el precio que se obtendrá por lote de viviendas que se construirán en un sitio previamente seleccionado. Para el caso de departamentos, el modelo busca maximizar el precio por planta de edificio. Como datos fijos en los modelos entraron las características del sitio y localización. Las  restricciones legales, variables arquitectónicas generales y restricciones económicas también se incluyeron como datos fijos. Las otras características funcionales de la vivienda y el precio se determinaron por los modelos de optimización. Los modelos fueron probados, encontrándose que

¿CÓMO IMPLEMENTAR UN MODELO DE VOLATILIDAD USANDO LENGUAJE R?

Directory of Open Access Journals (Sweden)

FERNÁN VILLA GARZÓN

2011-12-01

Full Text Available El modelado y pronóstico de series de tiempo financieras es una actividad de interés económico para los agentes del mercado. Las series de tiempo provenientes de ésta área a menudo presentan relaciones dinámicas complejas entre sus variables las cuales pueden ser capturadas mediante modelos de volatilidad. Estos pueden ser implementados en la mayoría de entornos de programación existentes. Sin embargo, la implementación de los modelos es compleja por no tener pautas para diseñar e implementar su código. Dado que R es un entorno de programación gratuito y estable, en este trabajo se proponen algunas pautas para diseñar e implementar el código de un modelo de volatilidad en R; como caso de ejemplo, se propone la creación del paquete Volatility que incluye el modelo de volatilidad GARCH y se mostrará su aplicabilidad al modelar la volatilidad de una serie de tiempo real.

Accounting for segment correlations in segmented gamma-ray scans

International Nuclear Information System (INIS)

Sheppard, G.A.; Prettyman, T.H.; Piquette, E.C.

1994-01-01

In a typical segmented gamma-ray scanner (SGS), the detector's field of view is collimated so that a complete horizontal slice or segment of the desired thickness is visible. Ordinarily, the collimator is not deep enough to exclude gamma rays emitted from sample volumes above and below the segment aligned with the collimator. This can lead to assay biases, particularly for certain radioactive-material distributions. Another consequence of the collimator's low aspect ratio is that segment assays at the top and bottom of the sample are biased low because the detector's field of view is not filled. This effect is ordinarily countered by placing the sample on a low-Z pedestal and scanning one or more segment thicknesses below and above the sample. This takes extra time, however, We have investigated a number of techniques that both account for correlated segments and correct for end effects in SGS assays. Also, we have developed an algorithm that facilitates estimates of assay precision. Six calculation methods have been compared by evaluating the results of thousands of simulated, assays for three types of gamma-ray source distribution and ten masses. We will report on these computational studies and their experimental verification

Análisis de cambio de régimen en series de tiempo no lienales utilizando modelos TAR

Directory of Open Access Journals (Sweden)

Hermilson Velásquez

2004-12-01

Full Text Available En muchas situaciones, la teoría recomienda un determinado modelo predictivo para una serie de tiempo financiera. Sin embargo, algunos comportamientos de estas series hacen que el modelo no sea apropiado. Una de las razones para ello puede ser la no linealidad de esos comportamientos. Se propone tratar estas series con modelos TAR (modelo autorregresivo por tramos; dichos modelos se definen por una variable umbral, por lo que en general resulta ser un modelo temporal no lineal. Un modelo de este tipo se formula como una serie temporal con su rezago como variable umbral, donde d es un entero positivo denominado retardo umbral. La variable umbral se desconoce en la práctica, y es importante saber cómo determinarla; en este artículo se explica cómo. Los modelos TAR se ilustran haciendo una modelación del PIB de España.

Análisis de cambio de régimen en series de tiempo no lineales utilizando modelos TAR

Directory of Open Access Journals (Sweden)

Fredy Pérez

2004-01-01

Full Text Available En muchas situaciones, la teoría recomienda un determinado modelo predictivo para una serie de tiempo financiera. Sin embargo, algunos comportamientos de estas series hacen que el modelo no sea apropiado. Una de las razones para ello puede ser la no linealidad de esos comportamientos. Se propone tratar estas series con modelos TAR (modelo autorregresivo por tramos; dichos modelos se definen por una variable umbral, por lo que en general resulta ser un modelo temporal no lineal. Un modelo de este tipo se formula como una serie temporal con su rezago como variable umbral, donde d es un entero positivo denominado retardo umbral. La variable umbral se desconoce en la práctica, y es importante saber cómo determinarla; en este artículo se explica cómo. Los modelos TAR se ilustran haciendo una modelación del PIB de España.

Métodos de diagnóstico em modelos logísticos trinomiais

OpenAIRE

Jose Alberto Pereira da Silva

2003-01-01

Os modelos logísticos trinomiais podem ser interpretados como uma extensão natural do modelo logístico binomial para situações em que a resposta admite apenas três resultados. Introduzimos inicialmente os modelos logísticos trinomiais e discutiremos em seguida alguns aspectos inferenciais, tais como estimação e testes. Medidas de qualidade do ajuste são também apresentadas. Contudo, o principal foco deste trabalho é a apresentação de métodos de diagnóstico. Mostramos que as técnicas usuais de...

Luchando infructuosamente contra la hidra: un modelo sencillo del narcotráfico

Directory of Open Access Journals (Sweden)

Ortiz Carlos Humberto

2002-12-01

Full Text Available En este artículo se presenta un modelo sencillo del narcotráfico que incorpora los riesgos de esta actividad. El modelo contribuye a explicar dos características notables del narcotráfico: la generación de ganancias extraordinarias y la gran capacidad de reproducción en condiciones de prohibición y represión. El modelo genera una relación directa entre la represión a la oferta –la estrategia
dominante de lucha contra el narcotráfico– y las características mencionadas.

Estudio de modelos de dispersión y su aplicación al control industrial

OpenAIRE

Villar Lagos, Germán

2017-01-01

El presente trabajo aborda el análisis de los modelos de dispersión de contaminantes en la atmósfera y su posible aplicabilidad en el control industrial particularmente de plantas industriales. En la primera parte se presenta una visión general sobre la atmósfera y una panorámica de los modelos de dispersión y terminología de los principales modelos y sus aplicaciones. En la segunda parte, se presenta el control industrial de planta industriales y se analiza la integración de los modelo...

Un modelo de eventos discretos para la simulación de sistemas de tiempo real

OpenAIRE

Páez, Francisco E.; Urriza, José M.; Orozco, Javier D.; Buckle, Carlos

2011-01-01

En este trabajo se presenta un modelo de eventos discretos para el diseño de simuladores de Sistemas de Tiempo Real. Los simuladores sirven para realizar comprobaciones de algoritmos, modelos, técnicas y para evaluar métricas de rendimiento. El modelo de eventos discretos se ajusta perfectamente a los sistemas dinámicos discretos como lo son los Sistemas de Tiempo Real. El modelo se desarrolla empleando la técnica de grafo de eventos, debido a su sencillez y facilidad de implementación.

Modelos alternativos para el análisis epidemiológico de la obesidad como problema de salud pública

Directory of Open Access Journals (Sweden)

Parra-Cabrera Socorro

1999-01-01

Full Text Available Los problemas de salud pública han sido estudiados desde muy diversas perspectivas y utilizando diferentes modelos teóricos y metodológicos. Dos modelos que han sido frecuentemente utilizados son el modelo epidemiológico clásico y el modelo epidemiológico social. Estos modelos emplean distintos criterios conceptuales, metodológicos e ideológicos. Se objetivó hacer una contrastación entre estos modelos de acuerdo a los criterios mencionados, utilizando el estudio de la obesidad como ejemplo de la utilización de estos modelos. Esta contrastación muestra que el conocimiento generado por cada modelo es muy distinto. Se discuten posibles áreas de complementariedad entre ambos modelos y la utilización de las ciencias sociales como estrategia para ampliar nuestro conocimiento sobre problemas de salud pública, en especial el problema de la obesidad.

Hydrophilic segmented block copolymers based on poly(ethylene oxide) and monodisperse amide segments

NARCIS (Netherlands)

Husken, D.; Feijen, Jan; Gaymans, R.J.

2007-01-01

Segmented block copolymers based on poly(ethylene oxide) (PEO) flexible segments and monodisperse crystallizable bisester tetra-amide segments were made via a polycondensation reaction. The molecular weight of the PEO segments varied from 600 to 4600 g/mol and a bisester tetra-amide segment (T6T6T)

Comparación entre modelos de molinos de viento

Directory of Open Access Journals (Sweden)

Julio Mario Rodríguez Devis

1983-09-01

Full Text Available Este trabajo hace parte de la Investigación sobre Aerogeneración patrocinada por CINDEC-COLCIENCIAS. Se evaluaron varios modelos de molinos de viento diseñados con la metodología de Jansen y Smulders y es la intención fundamental probar la versatilidad y limitación del túnel de viento instalado en el Laboratorio de Hidráulica de la Universidad Nacional, así como los problemas que se presentan en el ensayo de dichos modelos en él.

Spinal segmental dysgenesis

Directory of Open Access Journals (Sweden)

N Mahomed

2009-06-01

Full Text Available Spinal segmental dysgenesis is a rare congenital spinal abnormality , seen in neonates and infants in which a segment of the spine and spinal cord fails to develop normally . The condition is segmental with normal vertebrae above and below the malformation. This condition is commonly associated with various abnormalities that affect the heart, genitourinary, gastrointestinal tract and skeletal system. We report two cases of spinal segmental dysgenesis and the associated abnormalities.

Modelo de predisposición adquirida para el uso de alcohol en adolescentes argentinos

Directory of Open Access Journals (Sweden)

Gabriela Rivarola Montejano

2016-07-01

Full Text Available Se analizó, en una muestra de adolescentes argentinos, el modelo de predisposición adquirida. El modelo propone que el rasgo desinhibición influye de manera indirecta, a través de variables cognitivas, sobre el consumo de alcohol. La exposición a modelos de consumo del grupo de pares influye directa e indirectamente (mediante las expectativas hacia el alcohol sobre el uso de alcohol. Participaron 343 adolescentes asistentes a colegios públicos de educación media de la ciudad de Córdoba (Argentina. Se midió impulsividad, expectativas hacia el alcohol, motivos de consumo de alcohol, normas sociales de consumo y consumo de alcohol de los adolescentes. Para determinar el efecto de las variables señaladas como antecedentes del consumo se aplicó un análisis de senderos. Se propusieron dos modelos teóricos que diferían en la inclusión, o no, de las normas sociales del consumo de alcohol. Los resultados apoyan el modelo de predisposición adquirida e indican que el efecto de impulsividad sobre el consumo de alcohol es indirecto mediado por las expectativas hacia el alcohol. Aunque ambos modelos presentan adecuado ajuste a los datos, el modelo que incorpora el efecto de las normas sociales de consumo presenta un ajuste excelente. Los resultados de este trabajo, el primero de nuestro medio en evaluar el modelo de predisposición adquirida sobre el consumo de alcohol, destacan la utilidad de diagramar esfuerzos preventivos focalizados en el control de los impulsos, en las expectativas positivas hacia el alcohol y en la reducción de la percepción del consumo de los pares.

Modelo de negocio de Youtube

OpenAIRE

Julio Larrañeta Rubio; Amelia N. Ruiz Molina

2012-01-01

El uso de las nuevas tecnologías está implicando un profundo cambio en las pautas de consumo de los contenidos audiovisuales, y el consumidor, sobre todo los de menor edad, se están alejando de las formas tradicionales de consumo de estos contenidos. Los portales de video online suponen un nuevo modelo de negocio para los productos audiovisuales.

APROXIMACIÓN AL ESTUDIO DEL MODELO MENTAL SOBRE FOTOSÍNTESIS EN UN PROFESOR DE CIENCIAS NATURALES

Directory of Open Access Journals (Sweden)

Disana Navarro

2015-12-01

Desde una metodología cualitativa, se busca explorar el modelo, aplicando técnicas e instrumentos para dar cuenta de: ¿Cuál es el modelo que está presente en el profesor de Ciencias Naturales, sobre el concepto fotosíntesis?. A manera de ejercicio ilustrativo, se muestra el modelo de un profesor, caracterizando dos aspectos: el constituyente ontológico y el epistemológico de su representación, mediante la aplicación del modelo ONEPSI (Gutiérrez 2001; López A., Arcuri G., 2014. Por último, se hace un análisis de las aproximaciones del modelo del profesor, con el modelo científico construido a partir de la revisión teórica, buscando identificar fortalezas y debilidades en la construcción del concepto y sus posibles implicaciones en los procesos de enseñanza y aprendizaje.

El modelo de propaganda de Noam Chomsky: medios mainstream y control del pensamiento

OpenAIRE

Pineda, Antonio

2001-01-01

El objetivo de este trabajo es ofrecer una panorámica del modelo de propaganda desarrollado por el lingüista y activista político norteamericano Noam Chomsky, con especial incidencia en el análisis realizado por Chomsky y Edward Herman en «Los guardianes de la libertad». Recorreremos el mecanismo institucional, la estructura operativa de los medios, los efectos y los presupuestos ideológicos de los que parte el modelo, destacando las aportaciones del modelo chomskyano para el estudio del func...

El modelo socioproductivo impulsado por el Estado venezolano, 2007-2013: algunos impactos territoriales

OpenAIRE

María Andreina Salas-Bourgoin; Gloria Yulier Cadena Montero; Delfina Trinca Fighera; Nubis Miriam Pulido

2016-01-01

Para aproximarse a algunos de los impactos territoriales del modelo socioproductivo venezolano es necesario conocer algunos antecedentes de la organización del espacio, así como identificar los motivos y las premisas bajos las cuales, el Estado venezolano impulsa un ‘nuevo modelo económico productivo’. En la implementación de este nuevo modelo, el Estado se sustenta en un conjunto de leyes, planes y programas que proponen cambios en las relaciones sociales de producción, lo que no excluye...

BALANCED SCORECARD PARA EMPRENDEDORES: DESDE EL MODELO CANVAS AL CUADRO DE MANDO INTEGRAL

OpenAIRE

JOSÉ MANUEL SÁNCHEZ VÁZQUEZ; MARÍA LUISA VÉLEZ ELORZA; PEDRO ARAÚJO PINZÓN

2016-01-01

El Cuadro de Mando Integral (BSC) y el modelo Canvas pueden enlazarse como herramientas complementarias para los emprendedores. La primera desarrolla objetivos y medidas operativas en cuatro perspectivas principales para alcanzar la misión y estrategia. La segunda ha supuesto una (re-)evolución en la generación de modelos de negocio, estableciendo nueve apartados que reflejan su lógica. En el artículo se desarrolla un modelo de trabajo que, partiendo de la necesidad de dispo - ner de un B...

Gestão educativa gerencial: superação do modelo burocrático? Gestión educativa gerencial: ¿superación del modelo burocrático? Educational management: overcoming the bureaucratic model?

Directory of Open Access Journals (Sweden)

Suêldes de Araújo

2011-03-01

Full Text Available O estudo discute as mudanças ocorridas na gestão pública e suas repercussões no campo educacional a partir da adoção do modelo flexível de produção. Parte do pressuposto de que as modificações ocorridas nas sociedades contemporâneas foram influenciadas pela necessidade de reorganização do capital que, em crise, tentava superar o modelo taylorista/fordista de produção, por um modelo mais ágil, mais flexível que atendesse às atuais exigências do mercado. Para a implementação da nova gestão pública, os países latino-americanos passaram a utilizar estratégias que tinham, como referência, o modelo empresarial e se baseavam em critérios de eficiência, de eficácia e de produtividade. Nesse novo paradigma gerencial, defendia a substituição do modelo burocrático de gestão por um modelo descentralizado, com foco no atendimento ao cliente. Essas diretrizes tiveram uma ampla repercussão no campo educacional e foram disseminadas pelos organismos internacionais. Os estudos evidenciam que o modelo de gestão gerencial não têm conseguido superar o modelo de gestão burocrática que existia no interior da escola; o que se constata é a transformação desta em uma burocracia flexível, coerente com o novo modelo de produção.Este estudio discute los cambios ocurridos en la gestión pública y sus repercusiones en el área educacional a partir de la adopción del modelo flexible de producción. Parte de la idea de que las modificaciones ocurridas en las sociedades contemporáneas son fruto de la necesidad de reorganización del capital que, estando en crisis, trataba de superar el modelo taylorista/ fordista de producción, por un modelo más ágil, más flexible que atendiera las actuales exigencias del mercado. Para la implementación de la nueva gestión pública, los países latinoamericanos pasaron a utilizar estrategias que tenían, como referencia, el modelo empresarial y que se basaban en criterios de eficiencia

The startup performance and microbial distribution of an anaerobic baffled reactor (ABR) treating medium-strength synthetic industrial wastewater.

Science.gov (United States)

Jiang, Hao; Nie, Hong; Ding, Jiangtao; Stinner, Walter; Sun, Kaixuan; Zhou, Hongjun

2018-01-02

In this study, an anaerobic baffled reactor (ABR) with seven chambers was applied to treat medium-strength synthetic industrial wastewater (MSIW). The performance of startup and shock test on treating MSIW was investigated. During the acclimation process, the chemical oxygen demand (COD) of MSIW gradually increased from 0 to 2,000 mg L -1 , and the COD removal finally reached 90%. At shock test, the feeding COD concentration increased by one-fifth and the reactor adapted very well with a COD removal of 82%. In a stable state, Comamonas, Smithella, Syntrophomonas and Pseudomonas were the main populations of bacteria, while the predominant methanogen was Methanobacterium. The results of chemical and microbiological analysis indicated the significant advantages of ABR, including buffering shocks, separating stages with matching microorganisms and promoting syntrophism. Meanwhile, the strategies for acclimation and operation were of great importance. Further work can test reactor performance in the treatment of actual industrial wastewater.

Psicosinergia en Millon: Del modelo Biopsicosocial al modelo Ecológico

OpenAIRE

Jesús R. Herrero Sánchez

2014-01-01

Desde la publicación de Psicopatología Moderna, el modelo psicopatológico de Millon ha evolucionado sustantivamente. En su forma actual, Millon afirma que la estructura de una ciencia clínica consiste en cuatro elementos principales: una teoría que explica los fenómenos bajo observación, (b) una taxonomía que categoriza estos fenómenos en dimensiones significantes, (c) una instrumentación que mide estos fenómenos, y (d) una intervención que permite tratar los casos problemáticos. Este artícul...

Automatic Melody Segmentation

NARCIS (Netherlands)

Rodríguez López, Marcelo

2016-01-01

The work presented in this dissertation investigates music segmentation. In the field of Musicology, segmentation refers to a score analysis technique, whereby notated pieces or passages of these pieces are divided into “units” referred to as sections, periods, phrases, and so on. Segmentation

Acoplamiento de modelos de transporte de solutos y de modelos de reacciones químicas

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Samper, J.

1993-08-01

ímicos asociados a reacciones de diversa naturaleza. La mayoría de los modelos de transporte de solutos tienen en cuenta de forma rigurosa los procesos hidrodinámicos, pero sólo consideran las interacciones de tipo químico de forma muy simplificada. Por otro lado, los modelos de especiación química contemplan una gran variedad de procesos químicos en condiciones de equilibrio químico, aunque sólo son aplicables a sistemas acuáticos estáticos sin flujo. En la última década se han desarrollado un número considerable de modelos acoplados que contemplan, con grados muy variables de sofisticación, tanto los procesos hidrodinámicos como los químicos. Estos modelos contienen por un lado las ecuaciones diferenciales en derivadas parciales (EDP correspondientes al transporte de solutos y las correspondientes a los. procesos químicos, que en la hipótesis de equilibrio químico, son ecuaciones algebraicas no lineales. Un aspecto importante en la solución del problema es la adecuada selección de las variables primarias dependientes, las cuales satisfacen las ecuaciones de transporte. La inadecuada elección de las variables primarias limita la aplicabilidad del método de solución a sistemas químicos mixtos que contienen reacciones lentas (cinética y rápidas (equilibrio. Una característica común de la mayoría de los modelos existentes es la extraordinaria exigencia de tiempos de cálculo que motiva que con determinados enfoques sólo sea viable la solución de problemas unidimensionales.

MDA Y EL PAPEL DE LOS MODELOS EN EL PROCESO DE DESARROLLO DE SOFTWARE

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Juan Bernardo Quintero

2007-12-01

Full Text Available El papel de los modelos es fundamental en el desarrollo de software para potenciar el reúso de los diferentes elementos del software y facilitar la labor de los diferentes roles que participan del proceso. La Arquitectura Dirigida por Modelos (MDA propone un proceso de desarrollo basado en la realización y transformación de modelos. Los principios en los que se fundamenta MDA son la abstracción, la automatización y la estandarización. El proceso central de MDA es la transformación de modelos que parten del espacio del problema (CIM hasta modelos específicos de la plataforma (PSM, pasando por modelos que describen una solución independientemente de la computación (PIM. Para explicar el papel de los modelos en el proceso de desarrollo de software este artículo explora los principales conceptos presentados en la propuesta de MDA.The role of models is critical in software development to enable the reuse of different software elements and to aid the work of several roles involved in the process. Model Driven Architecture (MDA suggests a development process based on models realization and transformation. The principles in which MDA is based are abstraction, automation, and standardization. The central process of MDA is the transformation of models from the problem space (CIM to platform specific models (PSM, passing across models describing a platform independent solution (PIM. In order to explain the model role in the software process development, this paper explores the main concept presented in the MDA proposal.

Modelo de pronóstico de reoperación en cirugía abdominal

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Caridad de Dios Soler Morejón

2016-12-01

Full Text Available Introducción: En presencia de complicaciones infecciosas intrabdominales postoperatorias, la decisión de reoperar es todavía difícil para el cirujano actuante. Los modelos matemáticos representan una buena ayuda al diagnóstico en estas condiciones. Método: Estudio prospectivo observacional de 300 pacientes post-cirugía abdominal ingresados en la unidad de cuidados intensivos del Hospital Calixto García desde enero de 2008 a enero de 2010. Los pacientes fueron aleatoriamente separados (2:1 en dos grupos; estimación (GE y validación (GV. En el GE se desarrollaron tres modelos estadísticos para la reoperación, que fueron validados en el GV .Estos modelos incluyeron variables, que en estudios anteriores demostraron su utilidad en el pronóstico, como el índice predictivo de reoperación aguda (ARPI y la presión intrabdominal (PIA Resultados: El modelo ARPI-PIA fue el mejor de los tres modelos, según el estadígrafo Hosmer-Lemeshow (calibración C=9,976 p=0.267, discriminación área bajo la curva ROC=0,989 IC 95% 0,976-1,000. Conclusión: La inclusión de la PIA junto al ARPI en un modelo matemático puede aumentar la certeza del pronóstico de reoperación en presencia de complicaciones infecciosas intrabdominales tras cirugía abdominal. Este modelo puede ser de utilidad en situaciones de recursos diagnósticos limitados.

¿Importa Europa en las elecciones europeas? Un modelo explicativo de las elecciones del 2009 al Parlamento Europeo

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Paolo Bellucci

2012-01-01

Full Text Available Este trabajo evalúa la validez de diferentes modelos interpretativos del comportamiento electoral en las elecciones europeas partiendo del resultado de junio de 2009. Nos centramos, en primer lugar, en modelos que conectan el voto europeo con aspectos políticos basados en el nivel nacional (modelo de segundo orden y en el ciclo electoral doméstico (modelo de ciclo electoral; en segundo lugar se evalúa la capacidad explicativa de un modelo reñido con las interpretaciones tradicionales, y basado en el papel de la posición de los partidos políticos y la campaña electoral (modelo de Europa importa. Finalmente, se avanza un modelo sintético, con el objetivo de proporcionar una más sólida explicación de las elecciones de 2009 al Parlamento Europeo.

Modelo geral das atividades da empresa General model of company activities

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José Celso Contador

2001-12-01

Full Text Available O modelo evidencia que as atividades de qualquer tipo de empresa, inclusive a de serviços, podem ser organizadas em quatro grupos (produção, atendimento, apoio e planejamento e que essa organização é aplicável à empresa como um todo, a qualquer órgão (departamento, seção e a qualquer célula de trabalho, inclusive a constituída por apenas um funcionário. O modelo, por mergulhar, como nenhum outro, nas profundezas da empresa, complementa outros modelos (Tavistock, Katz & Kahn, Kast & Rosenzweig. A comparação com o modelo da Cadeia de Valores de Porter e as vantagens apontadas no texto permitem concluir que o modelo é bastante adequado para a proposição de mudanças na empresa que melhorem sua posição competitiva.The model shows that the activities of any type of company, including service companies, can be divided into four groups (production, service, support, planning and that such organization is applicable to the company as a whole, to any part of it (division, department and even to single employees. Since the model, as no other, covers nearly all sections of the company, it complements other ones (Tavistock, Katz & Kahn, Kast & Rosenzweig. The comparison with Porter’s Chain of Values and the advantages shown in the text, allow the conclusion that this model is perfectly adequate to the proposed changes in the company and to the improvement of its competitiveness.

El derecho como modelo para las ciencias naturales

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Vittorio Villa

2005-12-01

Full Text Available El artículo comienza con una exposición del modo tradicional de entender, durante siglos, la relación entre ciencia jurídica y ciencias naturales. Describe después el cambio radical del contexto epistemológico de fondo que se ha producido en las últimas cuatro décadas. Expone luego cómo, dentro de ese cambio, va apareciendo el derecho como modelo para las ciencias naturales, en fuerza de dos tipos diversos de analogía entre el derecho y esas ciencias. La última parte está dedicada a proponer la concepción del autor sobre las razones de la elección del derecho como modelo

Segmented trapped vortex cavity

Science.gov (United States)

Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

2010-01-01

An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

Performance Analysis of Segmentation of Hyperspectral Images Based on Color Image Segmentation

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Praveen Agarwal

2017-06-01

Full Text Available Image segmentation is a fundamental approach in the field of image processing and based on user’s application .This paper propose an original and simple segmentation strategy based on the EM approach that resolves many informatics problems about hyperspectral images which are observed by airborne sensors. In a first step, to simplify the input color textured image into a color image without texture. The final segmentation is simply achieved by a spatially color segmentation using feature vector with the set of color values contained around the pixel to be classified with some mathematical equations. The spatial constraint allows taking into account the inherent spatial relationships of any image and its color. This approach provides effective PSNR for the segmented image. These results have the better performance as the segmented images are compared with Watershed & Region Growing Algorithm and provide effective segmentation for the Spectral Images & Medical Images.

Modelo mecánico para el análisis biomecánico del servicio de tenis

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Esperanza Navarro

2010-10-01

Full Text Available

El propósito de este artículo es plantear un nuevo modelo mecánico del cuerpo, adaptado a los gestos técnicos del tenis. El modelo consta de 28 puntos articulares, en él se definen barras y sólido-rígidos. Dicho modelo permite un estudio del gesto técnico completo. Se analizó un servicio filmado con dos cámaras a 250 fps de una jugadora con ranking WTA mundial 42. Los resultados reflejan la validez de dicho modelo ya que nos permite cuantificar la evolución de la energía de toda la cadena cinética.
Palabras Clave: Modelo, mecánico, biomecánica, servicio, tenis.

Modelo de negocio de Youtube

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Julio Larrañeta Rubio

2012-04-01

Full Text Available El uso de las nuevas tecnologías está implicando un profundo cambio en las pautas de consumo de los contenidos audiovisuales, y el consumidor, sobre todo los de menor edad, se están alejando de las formas tradicionales de consumo de estos contenidos. Los portales de video online suponen un nuevo modelo de negocio para los productos audiovisuales.

UN MODELO ELÉCTRICO DE ESTRUCTURAS ALGEBRAICAS

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Gabriel Poveda Ramos

Full Text Available Los libros y los cursos de Álgebra Abstracta (o Álgebra Moderna definen y estudian varios tipos de estructuras algebráicas, como los grupos, los espacios vectoriales, los anillos, los ideales y los cuerpos (o campos de racionalidad. Estas estructuras se definen y se analizan en términos de unas operaciones que se caracterizan mediante propiedades que se presentan como salidas de la nada y que en realidad son solamente inferidas por abstracción de operaciones muy conocidas en disciplinas más elementales como la Geometría Euclidiana, la Teoría de Números y el Análisis Real. Pero nada se dice allí acerca de que hay sistemas de objetos físicos con relaciones mutuas, que son modelos (o ejemplos rigurosamente fieles de tales estructuras algebraicas. Aquí se presenta uno de tales modelos, que está constituido por una clase de objetos eléctricos llamados cuadripolos, y que pueden conectarse mutuamente en paralelo (como ejemplo de una «suma» de tales cuadripolos y en serie (como ejemplo de un «productos entre ellos». En este sistema, y con estas dos operaciones eléctricas, se muestra, por consideraciones eléctricas, que se puede formar un modelo eléctrico de varias estructuras algebraicas: de un grupo conmutativo, de un espacio vectorial, de un anillo de entericidad y de un campo de racionalidad.

Funções de afilamento não segmentadas e segmentadas para Tectona grandis na região centro-sul matogrossense Non-segmented and segmented taper models to Tectona grandis in center-southern region of Mato Grosso

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Sidney Fernando Caldeira

2012-12-01

Full Text Available O objetivo deste estudo foi comparar a acurácia dos modelos polinomiais não segmentados do quinto grau e de Hradetzky de 1976 e os segmentados de Max e Burkhart de1976 e Clark et al. de 1991, na estimativa dos diâmetros ao longo do fuste de Tectona grandis L.f., com ajustes para o conjunto total dos dados e por classe de diâmetro, em um povoamento com 16 anos, na região centro- sul matogrossense. A base de dados foi composta por 114 árvores, cubadas pela metodologia de Hohenadl modificada e distribuídas em classes de diâmetro. O ajuste dos modelos foi avaliado em função do coeficiente de determinação corrigido, erro padrão da estimativa e pela distribuição dos resíduos em porcentagem. A acuracidade dos modelos ao longo do fuste foi avaliada pelo desvio, desvio padrão das diferenças, somatório de quadrado dos resíduos relativos e a porcentagem dos resíduos. A Equação de Hradetzky foi a que apresentou o melhor ajuste para estimar os diâmetros ao longo do fuste de Tectona grandis tanto para o conjunto total dos dados quanto para as classes de diâmetro com os menores valores nas estatísticas auxiliares, exceto na Classe 3, onde a equação selecionada foi a de Clark et al. The aim of this study was to compare the accuracy of the non-segmented polynomial models of Fifth degree and Hradetzky from 1976 and the segmented models of Max and Burkhart from 1976 and Clark et al. from 1991, in estimating diameters along the stem of Tectona grandis L.f., with adjustments for the full set of data and by diameter class in a 16 years old stand in the center–southern region of Mato Grosso State, Brazil. The database consisted of 114 trees, scaled by the modified Hohenadl method and distributed in diameter classes. The models adjustments were evaluated according to the adjusted coefficient of determination, standard eError of estimate and distribution of residuals. The accuracy of the models along the stem was evaluated by deviation

Crescimento e produção de plantios comerciais de eucalipto estimados por duas categorias de modelos

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Renato Vinícius Oliveira Castro

2013-03-01

Full Text Available O objetivo deste trabalho foi avaliar e comparar duas categorias de modelos de crescimento e produção em plantios comerciais de eucalipto. Para isso, foram ajustados um modelo de crescimento e produção para povoamento e outro para árvore individual, por meio de equações simultâneas e redes neurais artificiais, respectivamente. O volume de madeira por área foi estimado em diferentes idades e classes de produtividade. Foram avaliados dados de 63 parcelas permanentes de plantios clonais, não desbastados, do híbrido Eucalyptus grandis x E. urophylla, com os dados de 33 parcelas utilizados para o ajuste do modelo e o treinamento das redes neurais, e os das 30 parcelas restantes, para a validação dos modelos. As duas categorias de modelos ajustaram-se bem aos dados observados. No entanto, na validação dos modelos com dados independentes, o volume de madeira por área foi mais bem estimado com o modelo para árvore individual.

MODELOS PARA EL ANÁLISIS Y DIAGNÓSTICO DE EQUIPOSDE TRABAJO

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Carlos Alberto Franco Gutiérrez

2004-01-01

Full Text Available En este artículo presentaremos variosmodelos para el análisis de la opera-ción de los equipos de trabajo queayudan a conocer el estado de efecti-vidad con que está trabajando el equi-po, con el fin de contribuir a conse-guir las condiciones para una opera-ción que eleve su productividad. El primer modelo que presentaremoses el de Hackman. Posteriormentenos centraremos en el denominadotradicional y finalmente en el mode-lo de las 3P y 3 C.El primer modelo determina las con-diciones necesarias para satisfacerciertas condiciones de efectividad, elsegundo se centra en tres factoresgenerales que determinan la produc-tividad y el rendimiento y el tercermodelo considera los factores clavespara la operación de equipos exitosos.

Desarrollo No Perturbativo para el Modelo de Hubbard Generalizado

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Oscar P. Zandron

2010-01-01

Full Text Available Se extienden a un estado superconductor nuestros resultados previamente obtenidos para un estado normal en el marco del formalismo Lagrangiano. Se considera la expansión noperturbativa a N grande aplicada a un modelo generalizado de Hubbard describiendo N bandas degeneradas correlacionadas. Se obtienen la diagramática Feynman del modelo y se calculan y analizan las cantidades físicas renormalizadas. Nuestro propósito es obtener la corrección 1/N de los propagadores bosónico y fermiónico renormalizados cuando se tiene en cuenta un estado de condensación de pares de Cooper.

Un modelo postkeynesiano simple de inestabilidad financiera y ciclos

OpenAIRE

Óscar de Juan Asenjo; Josep González Calvet

2003-01-01

En este trabajo se examina la interacción entre el sector real de la economía (representado por la tasa de crecimiento) y el sector financiero (representado por la tasa de interés). Se utiliza el modelo depredador-presa propuesto en 1926 por los científicos naturales Lotka y Volterra, que fue aplicado por primera vez al ámbito económico por Goodwin en 1967. A diferencia de los modelos convencionales del ciclo económico, cuyo punto de partida son las perturbaciones exógenas sobre la economía r...

Modelo de estimação de Brand Equity

OpenAIRE

Marta Olívia Rovedder de Oliveira

2013-01-01

Embora haja um consenso sobre a importância do valor da marca, um modelo de estimação único e uniformemente aceito ainda não surgiu, nem na perspectiva baseada no cliente ou consumidor nem na perspectiva da firma ou financeira. Assim, os profissionais de marketing ainda são desafiados a estimar o valor da marca. Além disso, é importante para a construção de um modelo de estimativa de valor da marca detectar as percepções dos consumidores e também apresentar uma estimativa monetária do valor d...

Modelo para la Predicción Energética de una Instalación Hotelera

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Adriana V. Acosta

2011-10-01

Full Text Available Resumen: Este artículo describe la obtención y validación de un modelo de predicción energética para el hotel Meliá Habana de la ciudad Habana en Cuba. El modelo obtenido emplea el método de series de tiempo radiantes para la determinación de la carga térmica de los bloques habitacionales de la instalación. El modelo es implementado en el lenguaje de programación MatLab®. La validación experimental del modelo se realiza con mediciones reales del consumo energético diario del hotel. El valor de uso del modelo obtenido es apreciable para estudios de comportamiento energético y para la implementación de estrategias avanzadas de control. Palabras clave: Modelado, Control de la Energía, Coeficientes de Temperatura, Validación

Segmental Vitiligo.

Science.gov (United States)

van Geel, Nanja; Speeckaert, Reinhart

2017-04-01

Segmental vitiligo is characterized by its early onset, rapid stabilization, and unilateral distribution. Recent evidence suggests that segmental and nonsegmental vitiligo could represent variants of the same disease spectrum. Observational studies with respect to its distribution pattern point to a possible role of cutaneous mosaicism, whereas the original stated dermatomal distribution seems to be a misnomer. Although the exact pathogenic mechanism behind the melanocyte destruction is still unknown, increasing evidence has been published on the autoimmune/inflammatory theory of segmental vitiligo. Copyright © 2016 Elsevier Inc. All rights reserved.

Segmental vitiligo with segmental morphea: An autoimmune link?

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Pravesh Yadav

2014-01-01

Full Text Available An 18-year old girl with segmental vitiligo involving the left side of the trunk and left upper limb with segmental morphea involving the right side of trunk and right upper limb without any deeper involvement is illustrated. There was no history of preceding drug intake, vaccination, trauma, radiation therapy, infection, or hormonal therapy. Family history of stable vitiligo in her brother and a history of type II diabetes mellitus in the father were elicited. Screening for autoimmune diseases and antithyroid antibody was negative. An autoimmune link explaining the co-occurrence has been proposed. Cutaneous mosiacism could explain the presence of both the pathologies in a segmental distribution.

Market Segmentation in Business Technology Base: The Case of Segmentation of Sparkling

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Valéria Riscarolli

2014-08-01

Full Text Available A common market segmentation premise for products and services rules consumer behavior as the segmentation center piece. Would this be the logic for segmentation used by small technology based companies? In this article we target at determining the principles of market segmentation used by a vitiwinery company, as research object. This company is recognized by its products excellence, either in domestic as well as in the foreign market, among 13 distinct countries. The research method used is a case study, through information from the company’s CEOs and crossed by primary information from observation and formal registries and documents of the company. In this research we look at sparkling wines market segmentation. Main results indicate that the winery studied considers only technological elements as the basis to build a market segment. One may conclude that a market segmentation for this company is based upon technological dominion of sparkling wines production, aligned with a premium-price policy. In the company, directorship believes that as sparkling wines market is still incipient in the country, sparkling wine market segments will form and consolidate after the evolution of consumers tasting preferences, depending on technologies that boost sparkling wines quality. 

Modelo de negocio para optimizar las estrategias productivas de personalización en masa

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Luis Miguel Arroyo Gutierrez

2015-01-01

Full Text Available Objeto: Describir un modelo general de proceso y negocio de personalización en masa. Destacar los elementos claves para llevar a cabo la personalización en masa como estrategia productiva principal o complementaria de una empresa. El  modelo propuesto se basa en una revisión exhaustiva de la literatura y se define en su completa dimensión, describiendo diferentes etapas, elementos, interrelaciones y flujos de información; ofreciendo una perspectiva global hasta ahora inexistente en la literatura. Diseño/metodología: Se ha llevado una exhaustiva revisión de la literatura y no se ha encontrado un modelo o estructura del proceso de personalización en masa universalmente aceptada, ni tampoco una estructura amplia y de conjunto, que cubra y describa el proceso completo y pueda asimilarse a un modelo de negocio. Sin embargo en la literatura se ofrecen cinco enfoques parciales y diferentes  en las que los autores se han basado para proponer un  modelo de negocio integrado de personalización. Aportaciones y resultados: En este trabajo se ha definido y desarrollado el proceso general de  implantación de la personalización en masa en tres etapas, enfatizando las iteraciones que existen entre las ellas que le convierten en proceso retroalimentado. Se ha encontrado que el modelo resulta especialmente útil en la generación de valor. El modelo expone los principios para identificar el valor y como la generación de valor refleja la particularidad de la personalización en masa frente a otras estrategias Limitaciones: El modelo de negocio presentado es teórico, por ello es interesante desarrollar un contraste empírico. Así mismo, al ser un modelo de aplicación general no ha sido posible entrar en las peculiaridades de cada industria. Implicaciones prácticas: La estrategia productiva de personalización en masa permite la generación de valor ofreciendo productos que satisfacen preferencias individuales, con costes y eficiencias similares

Simultaneous denitrification and anaerobic digestion in GRAnular Bed Baffled Reactor (GRABBR)

International Nuclear Information System (INIS)

Baloch, M.I.; Akunna, J.C.

2002-01-01

This study elucidates the characteristics of compartmentalised anaerobic system seeded with UASB granules, called GRAanular Bed Baffled Reactor (GRABBR), for combined denitrification and anaerobic digestion processes. The reactor was used for the treatment of glucose enriched synthetic wastewater with various nitrate concentrations. The study was carried out with a 10 litre working volume GRABBR divided into 5 equal compartments operating at organic loading rate (OLR) of 20 kg COD/m 3 .d with a hydraulic retention time (HRT) of 6 hours. At these conditions, phase separation (between acidogenesis and methanogenesis) was created in the system and then the effect of varying nitrate concentrations (50-200 mg/l NO 3 -N) in the acidogenic zone (i.e. first compartment) was studied. Due to its unique compartmentalised design, denitrification was the major pathway for nitrate reduction with no noticeable dissimilatory nitrate reduction to ammonia (DNRA). More than 84% of all added nitrates were removed in the acidogenic zone, showing that acidogens possess high denitrifying capabilities. The denitrification rate increased with increase in nitrate concentration, with maximum value estimated as 175 mg NO 3 -N/l.h at influent nitrate concentration of 200 mg/l NO 3 -N in the acidogenic zone. Although nitrate addition resulted in lower methane production, COD removal efficiencies improved by up to 8% when compared with the reactor performance before nitrate addition. Furthermore, the alkalinity produced during denitrification improved the stability of the system by controlling the decrease in pH resulting from acidogenesis. The system encouraged simultaneous denitrification and anaerobic digestion in a single unit by accommodating denitrifiers in the early compartments and allowing methanogenesis to flourish in the downstream compartments of the system, thus minimising inhibition to methane producing bacteria by nitrates. (author)

Modelo integrativo de teorias cognitivas da motivação. Uma investigação realizada com professores

OpenAIRE

Jesus, Saul Neves de; Vieira, Luís Sérgio; Almeida, H.; Santos, J.; Gomes, Alexandra; Martins, C.

2009-01-01

Neste estudo começamos por fundamentar a pertinência de um modelo integrativo que integre diversas teorias cognitivistas da motivação, no sentido de explicar como é que diversas variáveis motivacionais se relacionam e influenciam mutuamente, para melhor compreender o empenhamento e também o bem-estar profissional. O modelo que apresentamos parte do Modelo do Desânimo Aprendido e dos Modelos Expectativa-Valor da Motivação Humana, em particular do Modelo da Discrepância Motivacional, mas pr...

Contra los modelos inalcanzables. Perfección, tecnología y sociedad

Directory of Open Access Journals (Sweden)

Luca Valera

2018-01-01

Full Text Available El presente artículo aborda el tema de la preocupación contemporánea por los desarrollos tecnológicos recientes, comenzando por la discusión actual sobre el tema de la perfección. Precisamente, una de las hipótesis con respecto a las causas de esta preocupación es el modelo de perfección que promueve la sociedad de la civilización tecnológica: un modelo inalcanzable. Una vez que hemos aclarado el hecho de que la idea de perfección, que inspira la contemporaneidad, es una "perfección metafísica intramundana" que busca eliminar ciertos aspectos corporales no deseados, podemos argumentar que los modelos sociales y culturales actuales no pueden alcanzarse por cuatro razones principales: son extrínsecos, globalizados, irreales y dependen de la lógica de la tecnología. En este contexto, y en base a estos modelos, el principal objetivo ético del ser humano se vuelve imposible: ser uno mismo.

CAPACIDAD PREDICTIVA DE MODELOS DE INSOLVENCIA CON BASE EN NÚMEROS CONTABLES Y DATOS DESCRIPTIVOS

Directory of Open Access Journals (Sweden)

Júlio Orestes da Silva

2012-09-01

Full Text Available En el Brasil la pesquisa sobre modelos de previsión de insolvencia se inició en la década de 1970, siendo que la mayor parte de los trabajos hizo uso del Análisis Discriminante como herramienta estadística del modelo. En los últimos años, se buscó verificar si es posible prever la insolvencia de las empresas utilizando datos descriptivos contenidos en los informes de las organizaciones. Así, este estudio tiene como objetivo verificar la capacidad de algunos modelos de previsión de insolvencia en prever la discontinuidad de empresas brasileñas que decretaron quiebra. La pesquisa se caracteriza como descriptiva y posee abordaje cuantitativo, realizado por medio de pesquisa documental. La muestra totalizó 13 empresas que decretaron quiebra entre los años de 1997 y 2003. Los resultados indican que la mayoría de los modelos de previsión de quiebra testados presentó resultados elevados de previsiones correctas. Los modelos de previsión de discontinuidad con base en informes descriptivos obtuvieron en media más previsiones asertivas en relación a la capacidad de prever la quiebra de las empresas. Esos descubrimientos demuestran que, a pesar de que algunas pesquisas apunten hacia la falta de validez de predictores creados en realidades empresariales diferentes, algunos modelos todavía poseen buena capacidad de previsión de insolvencia. Se concluye que tanto los modelos de previsión de insolvencia con base en números contables en relación a los modelos que se utilizan datos de informes descriptivos pueden prever la discontinuidad de las organizaciones. Por fin, se puede inferir que la mayoría de los modelos de previsión de quiebra que hacen uso de números contables pueden ser funcionales y capaces de prever la discontinuidad de las organizaciones.

¿Realmente existe convergencia regional en México? Un modelo de datos-panel TAR no lineal

Directory of Open Access Journals (Sweden)

Domingo Rodríguez-Benavides

2016-01-01

Full Text Available Este trabajo analiza la hipótesis de convergencia regional en México para el periodo 1970-2012 por medio de un modelo de crecimiento no lineal. La metodología empleada combina tres enfoques: el modelo panel autorregresivo de umbral (tar, threshold autorregresive, las pruebas de raíces unitarias en panel y el cálculo de los valores críticos a través de simulación bootstraping. Los resultados empíricos del modelo no lineal aplicado al pib per cápita de distintos grupos de estados de la república mexicana sugieren que el modelo propuesto es superior al modelo lineal y muestran evidencia de convergencia parcial y absoluta para el grupo de las 11 entidades “más ricas” en ciertos subperiodos.

Fluence map segmentation

International Nuclear Information System (INIS)

Rosenwald, J.-C.

2008-01-01

The lecture addressed the following topics: 'Interpreting' the fluence map; The sequencer; Reasons for difference between desired and actual fluence map; Principle of 'Step and Shoot' segmentation; Large number of solutions for given fluence map; Optimizing 'step and shoot' segmentation; The interdigitation constraint; Main algorithms; Conclusions on segmentation algorithms (static mode); Optimizing intensity levels and monitor units; Sliding window sequencing; Synchronization to avoid the tongue-and-groove effect; Accounting for physical characteristics of MLC; Importance of corrections for leaf transmission and offset; Accounting for MLC mechanical constraints; The 'complexity' factor; Incorporating the sequencing into optimization algorithm; Data transfer to the treatment machine; Interface between R and V and accelerator; and Conclusions on fluence map segmentation (Segmentation is part of the overall inverse planning procedure; 'Step and Shoot' and 'Dynamic' options are available for most TPS (depending on accelerator model; The segmentation phase tends to come into the optimization loop; The physical characteristics of the MLC have a large influence on final dose distribution; The IMRT plans (MU and relative dose distribution) must be carefully validated). (P.A.)

Strategic market segmentation

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Maričić Branko R.

2015-01-01

Full Text Available Strategic planning of marketing activities is the basis of business success in modern business environment. Customers are not homogenous in their preferences and expectations. Formulating an adequate marketing strategy, focused on realization of company's strategic objectives, requires segmented approach to the market that appreciates differences in expectations and preferences of customers. One of significant activities in strategic planning of marketing activities is market segmentation. Strategic planning imposes a need to plan marketing activities according to strategically important segments on the long term basis. At the same time, there is a need to revise and adapt marketing activities on the short term basis. There are number of criteria based on which market segmentation is performed. The paper will consider effectiveness and efficiency of different market segmentation criteria based on empirical research of customer expectations and preferences. The analysis will include traditional criteria and criteria based on behavioral model. The research implications will be analyzed from the perspective of selection of the most adequate market segmentation criteria in strategic planning of marketing activities.

Why segmentation matters: Experience-driven segmentation errors impair "morpheme" learning.

Science.gov (United States)

Finn, Amy S; Hudson Kam, Carla L

2015-09-01

We ask whether an adult learner's knowledge of their native language impedes statistical learning in a new language beyond just word segmentation (as previously shown). In particular, we examine the impact of native-language word-form phonotactics on learners' ability to segment words into their component morphemes and learn phonologically triggered variation of morphemes. We find that learning is impaired when words and component morphemes are structured to conflict with a learner's native-language phonotactic system, but not when native-language phonotactics do not conflict with morpheme boundaries in the artificial language. A learner's native-language knowledge can therefore have a cascading impact affecting word segmentation and the morphological variation that relies upon proper segmentation. These results show that getting word segmentation right early in learning is deeply important for learning other aspects of language, even those (morphology) that are known to pose a great difficulty for adult language learners. (c) 2015 APA, all rights reserved).

Mapa Hipertextual (MHTX): um modelo para organização hipertextual de documentos

OpenAIRE

Gercina Angela Borem de Oliveira Lima

2004-01-01

Este estudo visa a construção de um modelo estruturado semanticamente para auxiliar a organização e representação do conhecimento humano estruturado em hipertextos, baseado nas teorias da análise facetada e do mapa conceitual. O segundo passo neste estudo é a aplicação do modelo semântico para criar um protótipo chamado MAPA HIPERTEXTUAL (MHTX): um modelo para organização hipertextual de documentos que deverá ser utilizado para implementar a BTDECI UFMG (Biblioteca de Teses e Dissertações do...

El rendimiento en ELE en la enseñanza reglada: un modelo explicativo

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Roncel Vega, Víctor M.

2007-11-01

Full Text Available En este trabajo se describen los pasos seguidos en la construcción de un modelo explicativo del rendimiento en ELE en la enseñanza formal. Tras la estimación de un modelo empírico final, se pone de manifiesto la importancia de algunas variables de carácter afectivo como el autoconcepto del estudiante, la motivación y la ansiedad específica en la clase de idiomas, integradas en dicho modelo y, por lo tanto, responsables delRendimiento final en ELE en la enseñanza reglada.

INDUÇÃO DE TENDINOPATIA DEAQUILES EM MODELO ANIMAL: REVISÃO BIBLIOGRÁFICA

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Leticia Boldo de Sousa

2017-02-01

Full Text Available Tendinopatia é uma lesão no tendão que varia de dor e/ou inflamação à condição crônica. Afeta pessoas de meia-idade e atinge 14% dos atletas de elite. O tratamento é com medicação orientada pelo especialista, além de atividades físicas que fortalecem a região afetada e com muita fisioterapia, enquanto os sucessos cirúrgicos são baixos e requerem um tratamento de longa duração. Esta revisão bibliográfica tem como objetivo mostrar os diferentes tipos de protocolos usando  modelo animal para induzir tendinopatia de aquiles. Foram utilizados artigos dos últimos 5 anos, publicados no Lillacs, Pubmed e Scielo, descartando os que não usaram modelo mecânico de indução. Não há modelos ideais que se aproximam da realidade humana e cada um tem suas vantagens e desvantagens, sendo necessários mais estudos aprofundados de tendinopatia no aquiles em modelo animal.   Palavras-chave: tendão de Aquiles, tendinopatia, modelo animal, corrida. Área do Conhecimento: Ciências da Saúde

Selección de modelos y estimación bayesiana para la tasa de cambio semanal de Colombia.

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Norberto Rodriguez Niño

2010-05-01

Full Text Available Este documento revisa y aplica técnicas recientemente desarrolladas para la estimación bayesiana y la selección de modelos en el contexto del modelaje de series de tiempo para la volatilidad estocástica. Luego de ofrecer una revisión de la literatura sobre modelos generalizados autorregresivos condicionales, modelos de volatilidad estocástica y los resultados relevantes en métodos de cadenas de Markov y Montecarlo, se muestra un ejemplo aplicando dichas técnicas. La metodología de siete modelos diferentes se aplica a una serie de tiempo de la tasa de cambio semanal entre Estados Unidos y Colombia. El modelo GARCH, que utiliza una distribución Pearson tipo IV, se prefiere por su técnica de selección (Salto Reversible MCMC en comparación a otros modelos, entre los cuales se incluyen modelos de volatilidad estocástica con una distribución probabilística T-student.

El modelo de inventarios de mercancías considerando la interacción entre procesadores y especuladores

OpenAIRE

César Revoredo Giha

2008-01-01

Este artículo considera una versión alternativa del modelo de inventarios de mercancías bajo expectativas racionales, donde tanto especuladores como firmas procesadoras almacenan productos. El modelo identifica tanto los inventarios llevados por los procesadores como aquellos descritos por el modelo de oferta de inventarios. Sin embargo, en lugar de usar el motivo de conveniencia (retornos por conveniencia), la demanda por inventarios es derivada a partir de un modelo microeconómico de invent...

REFLEXIONES SOBRE UN MODELO AUTORIAL: PARA LA HISTORIA DE LA FOTOGRAFÍA EN COLOMBIA

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Santiago Rueda Fajardo

2011-04-01

Full Text Available Las historias fundacionales del medio fotográfico fueron escritas en el modelo autorial cuya creación se le atribuye a Beaumont Newhall. Este tipo de ralatos históricos presentan sintomas de desgaste, en especial ante el surgimeinto de nuevos modos de investigación. En nuestro país, donde la historia de la fotografía es un campo de estudios muy reciente, el modelo autorial apenas ha sido autorizado y tiene una aplicación vigente, especialmente si se le emplea a un modelo de investigación multidisciplinar. Este escrito tiene por objeto describir y proponer los posibles nuevos modelos y los beneficios que puede aportar, en especial si se utiliza y apoyándose en la interpretación iconológica.

Experimental study of hydrodynamic and operation start of a baffled anaerobic reactor treating sewage

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Ana Carolina Silveira Perico

2009-12-01

Full Text Available It is important to provide individual sanitation systems for sewage peri-urban communities or rural areas to minimize impacts on the environment and human health caused by sewage discharge in natura into water resources. In this context, the anaerobic digestion of effluent has been one of the main considered technologies due to easy implementation, material minimization and reduction in waste production. The objective of this work was to study a Baffled Anaerobic Reactor (BAR including its hydrodynamic characteristics, percentile of inoculum to be applied and reactor operation start. It was concluded that the flow is dispersed with 3.84% of dead spaces and that 20% of the cow manure provided best results; however, due to the high fiber content of the manure, its use is not recommended as inoculum. The BAR system, composed of four chambers, presented good performance for sewage treatment of a rural community in terms of organic substance removal (COD, turbidity and solids meeting effluent disposal standards of these parameters considering the Federal and Minas Gerais State legislation, in Brazil, even in a transient phase of operation, at temperatures below 20°C. However, the effluents from the BAR can’t be released into water bodies without other parameters such as nitrogen, phosphorus, fecal coliforms, and others are investigated to be conforming to those standards.

Modelo de Excelencia de Programas Formativos en Línea (MEPFL)

OpenAIRE

Olga María ALEGRE DE LA ROSA; Luis Miguel VILLAR ANGULO

2006-01-01

La mejora de la calidad de la docencia universitaria requiere el desarrollo profesional y docente del profesorado. Este artículo ilustra el Modelo de Excelencia de Programas Formativos en Línea (MEPFL) basado en el modelo europeo de aseguramiento de la calidad para la mejora de criterios, estándares e indicadores de un programa formativo. Los resultados de la aplicación del MEPFL indican la necesidad de políticas de calidad que apoyen las competencias de los evaluadores para mejorar los prog...

Modelo Didáctico Co - Sujeto en las Competencias Investigativas

OpenAIRE

Llanquiche Jara, Pilar Dansi

2017-01-01

El presente trabajo de tesis titulado: El modelo didáctico de co-sujeto en las competencias investigativas surge como respuesta a la problemática del bajo nivel de desarrollo de las competencias investigativas propedéuticas de los estudiantes de 5º grado de estudios de educación secundaria de la I.E. Independencia Americana del cercado de la ciudad de Arequipa. El objetivo planteado es elaborar y proponer un modelo didáctico co-sujeto para inculcar las competencias investigativas propedé...

Synergetic Effects of Runaway and Disruption Induced by VDE on the First Wall Damage in HL-2A

International Nuclear Information System (INIS)

Song Xianying; Yang Jinwei; Li Xu; Yuan Guoliang; Zhang Yipo

2012-01-01

The plasma facing component in HL-2A has been damaged seriously after disruption, and for this reason its operation is suspended for maintenance. The experimental phenomena and plasma configurations, calculated by the current filament code (CF-code) using the plasma parameters measured by diagnostics and the signals of the magnetic probes, confirm that the first wall is damaged by the synergetic effects of runaway electrons and disruption induced by a vertical displacement event (VDE). When the plasma column is displaced upward/downward, the strong runaway electrons normally hit the baffle plate of the MP 3 or MP 1 coil in the upper and lower divertor during the disruption, causing the baffle plates to be holed and wrinkled by the energetic runaway current, and water (for cooling or heating the baffle plates) to leak into the vacuum vessel. Another disastrous consequence is that bellows underlying the baffle plate and outside the coil of MP 3 for connecting two segments of the jacket casing pipe are punctured by arcing. The arc may be part of the halo current that forms a complete circuit. The experimental phenomena are indirect but compelling evidence for the existence of a halo current during the disruption and VDE, though the halo current has not been measured by the diagnostics in the HL-2A tokamak.

Synergetic Effects of Runaway and Disruption Induced by VDE on the First Wall Damage in HL-2A

Science.gov (United States)

Song, Xianying; Yang, Jinwei; Li, Xu; Yuan, Guoliang; Zhang, Yipo

2012-03-01

The plasma facing component in HL-2A has been damaged seriously after disruption, and for this reason its operation is suspended for maintenance. The experimental phenomena and plasma configurations, calculated by the current filament code (CF-code) using the plasma parameters measured by diagnostics and the signals of the magnetic probes, confirm that the first wall is damaged by the synergetic effects of runaway electrons and disruption induced by a vertical displacement event (VDE). When the plasma column is displaced upward/downward, the strong runaway electrons normally hit the baffle plate of the MP3 or MP1 coil in the upper and lower divertor during the disruption, causing the baffle plates to be holed and wrinkled by the energetic runaway current, and water (for cooling or heating the baffle plates) to leak into the vacuum vessel. Another disastrous consequence is that bellows underlying the baffle plate and outside the coil of MP3 for connecting two segments of the jacket casing pipe are punctured by arcing. The arc may be part of the halo current that forms a complete circuit. The experimental phenomena are indirect but compelling evidence for the existence of a halo current during the disruption and VDE, though the halo current has not been measured by the diagnostics in the HL-2A tokamak.

PROGRESIÓN DEL APRENDIZAJE BASADO EN MODELOS: LA ENSEÑANZA DEL APRENDIZAJE DEL SISTEMA NERVIOSO.

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Alma Adrianna Gómez Galindo

2014-12-01

Full Text Available En esta comunicación presento una propuesta de desarrollo curricular basado en la modelización. Se recuperan las aportaciones de la ciencia escolar en la que se afirma que una de las actividades primordiales de los alumnos es la construcción de modelos teóricos escolares. Los modelos se entienden como tramas de ideas que permiten explicar teóricamente un fenómeno, estas explicaciones se ajustan altamente a las intervenciones experimentales, discursivas y representacionales de los alumnos sobre el mundo. Esta propuesta de desarrollo curricular se basa en la generación de una hipótesis de progresión en el desarrollo de los modelos, asentada en las aportaciones teóricas del área, definiéndose un modelo blanco y cinco modelos intermediarios. Cada modelo intermediario va dirigido a un ciclo educativo, abarcando desde pre-escolar hasta educación secundaria. A partir de la hipótesis de progresión inicial se diseñaron secuencias de aprendizaje, las de pre-escolar y primaria fueron discutidas con los docentes de un jardín de niños y una primaria (10 docentes y llevadas al aula en condiciones naturales, fueron analizadas y publicadas. A partir del análisis y de la retroalimentación con docentes se reconstruyó la hipótesis de progresión. Consideramos que esta metodología de desarrollo curricular basada en modelización y progresión el aprendizaje, en la cual se retroalimentan teoría y práctica, nos permite generar propuestas de desarrollo para modelos escolares más auténticos, los cuales no consideran únicamente los modelos científicos eruditos, sino las aportaciones del profesorado y los resultados de la práctica escolar con alumnos.

Estrategias y modelos de financiación del documental interactivo y transmedia

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Arnau Gifreu-Castells

2014-12-01

Full Text Available La revolución digital ha facilitado la expansión denuevos formatos audiovisuales que se reinventan brindando nuevas posibilidades al público. El documental interactivo es uno de los géneros en gestación en continuo crecimiento que seha beneficiado de estas nuevas lógicas, modelos y dinámicas. La novedad radica en la posibilidad por parte del espectador de interactuar con la historia. El objetivo de este artículo es dara conocer el género documental interactivo y analizar sus principales métodos de financiación. Para ello estudiaremos las características de este formato, abordaremos los modelos de financiación del documental tradicional, interactivo y transmedia, y profundizaremos en la manera de financiar algunos documentales como Alma, hija de la violencia (2012, 0 responsables (2013 y Las Sinsombrero (2014. En este trabajo analizaremos la evolución del género documental con el objetivo de describir tres etapas o periodos: la audiovisual, la interactiva y la transmedia. Cada una de estas fases contempla el uso de un conjunto de estrategias y modelos de financiación comunes y necesarios para la viabilidad económica de los proyectos. En cada modelo propuesto reflexionaremos sobre los principales mecanismos de financiación que requiere y analizaremos tanto los formatos tradicionales como los nuevos formatos de financiación que componen el modelo de negocio documental en su conjunto.

Modelos de crescimento resultantes da combinação e variações dos modelos de Chapman-Richards e Silva-Bailey aplicados em Leucaena leucocephala (Lam. de Wit.

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Cícero Carlos Ramos de Brito

2010-08-01

Full Text Available O objetivo deste trabalho foi desenvolver novos modelos de crescimento para recursos florestais aplicados à leucena [Leucaena leucocephala (Lam. de Wit], tendo como base as hipóteses biológicas propostas por Chapman-Richards e Silva-Bailey. O experimento de leucena foi conduzido na Estação Experimental da Empresa Pernambucana de Pesquisa Agropecuária - IPA, Caruaru, PE. Foram utilizadas 544 árvores de leucena de um experimento com vinte remedições realizadas ao longo de 12 anos. Compararam-se novos modelos de crescimento resultantes da combinação e variações dos modelos de Chapman-Richards e Silva-Bailey, bem como outros comumente usados em recursos florestais. Para a seleção das equações, utilizaram-se o Índice de Ajuste (IA, o erro-padrão da estimativa e a distribuição gráfica dos resíduos. Os resultados indicaram que todos os modelos testados se ajustaram de maneira satisfatória aos dados, podendo ser utilizados para se estimar o crescimento em altura da leucena.

Modelo de dinámica lateral de vehículo mediante bond graph

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Juan Carlos Parra Márquez

2008-07-01

Full Text Available Este trabajo presenta los resultados de la investigación, cuyo objetivo es obtener un modelo matemático que permita determinar la dinámica lateral de un vehículo mediante el uso de Bond Graph. Este modelo es válido para robótica móvil. Los análisis de comportamiento del modelo han sido probados con simulaciones típicas del movimiento lateral de un vehículo. Finalmente, este modelo ha sido obtenido e implementado mediante el software 20-Sim. This paper presents the results of a research whose objective was to find a mathematical model in order to determine the lateral dynamic of Vehicle by means of the use of Bond Graph. This model is valid also for mobile robotics. The analyses of behavior of the model were realized across typical simulations of a vehicle in lateral movement. Finally, this mathematical model was obtained and implemented across the software 20-Sim.

Beneficios de utilizar modelos ad-hoc de gestión de inventarios en presencia de flujos de retorno

OpenAIRE

Juan Pedro Sepúlveda Rojas; Felipe Baesler Abufarde; Domingo Antonio Núñez Morales

2010-01-01

En este trabajo se analiza el impacto de la logística reversa en los modelos de gestión de inventarios a través del análisis de las implicancias y extensiones de algunos modelos estudiados en la literatura. A través de experimentación con modelos de inventario determinísticos encontramos que en gran parten de los escenarios estudiados, los costos de utilizar modelos clásicos de gestión de inventarios son superiores a modelos que toman en cuenta los flujos de retorno. Solo en casos muy particu...

¿Divinas? Moda y blogs de maquillaje: modelos femeninos

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Arana Caballero, Rocío

2016-04-01

Full Text Available This paper aims to draw a qualitative comparison between two recent books on fashion, in order to attempt a parallel reading on female models, and secondly, provides a brief overview of beauty blogs. In the first part of the work, the analysis of the recent Anagram essay prize winner, ¡Divinas! Modelos, poder y mentiras (Soley-Beltran, 2015, which considers the female identity as a transvestite; as a coat-hanger to be used or changed depending on the interests and situations in hand, culminates in several questions: is this the model of the modern woman? Is there a female essence scent?. The work also attempts to give a brief overview of beauty blogs to try to answer one question: are there ethical and aesthetic concerns behind these spaces?.Este trabajo pretende por una parte analizar cualitativamente dos libros recientes sobre moda, en una lectura paralela que compare modelos femeninos sacando conclusiones sobre ellos, y en segundo término realizar una breve panorámica de blogs de belleza. En la primera parte del trabajo, el análisis del reciente premio de ensayo Anagrama, ¡Divinas! Modelos, poder y mentiras (Soley-Beltran, 2015, que considera la identidad femenina como un travesti, una percha de usar y cambiar según intereses y situaciones, culmina en varios interrogantes: ¿es este el modelo de mujer actual? ¿Existe una esencia femenina?. Tras ello y como complemento, se desarrolla una breve panorámica de blogs de maquillaje, con cuatro calas en este universo, para intentar responder a una pregunta: ¿existe realmente una inquietud ética y estética detrás de estos espacios?.

¿Qué son los modelos físicos?

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José Luis Rolleri

2013-01-01

Full Text Available En este artículo analizamos los principales conceptos propuestos de modelo con el propósito de resaltar el carácter idealizado y abstracto de los modelos físicos, que generalmente es pasado por alto en la literatura filosófica relevante desde diversas posiciones, como el instrumentalismo y el pragmatismo; el cual, sin embargo tiene importantes implicaciones en problemas filosóficos como el del realismo científico. Desde una posición conceptualista, sostenemos que los modelos desidealizados son los vehículos para conceptualizar los sistemas físicos desde la perspectiva de una teoría. In this paper we analyze the main intended concepts of model in order to underline the idealized and abstract character of physical models, that generally is overpass in the relevant philosophical literature from diverse positions on the scientific knowledge, such as instrumentalism and pragmatism, which however has important implications on philosophical problems such as that of scientific realism. From a conceptualistic position we hold that the de-idealized models are the vehicles to conceptualized physical systems from the perspective of a theory

Modelos de reproducción en desequilibrio: Nuevos desarrollos

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Edith Klimovsky

2010-04-01

Full Text Available En este artículo se presentan los nuevos resultados que hemos obtenido a partir de los modelos clásicos bisectoriales de reproducción en desequilibrio elaborados conjuntamente con Carlo Benetti y Christian Bidard, y publicados en la cuarta y última parte del libro Capital, salaire et crises, 2006. Se distinguen las extensiones de los modelos básicos y las nuevas líneas de investigación encaminadas por un lado a estudiar la formación de los precios de mercado y su dinámica, y por el otro a analizar las condiciones de las crisis de reproducción en el modelo de Marx.   ABSTRACT This paper presents the new results we obtained on the basis of the classical bi-sectoral disequilibrium models of reproduction, jointly developed by Carlo Benetti, Christian Bidard and Edith Klimovsky as published in the last section of the book Capital, salaire et crises, 2006. A distinction is drawn between extensions of the basic models, and new research aimed at: a studying market price formation and its dynamics, and b analyzing the conditions of reproduction crisis in Marx’ model.

Condominios: modelo de organización administrativa

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Luz Alexandra Montoya Restrepo

2016-05-01

Full Text Available Este artículo recopila las ideas fundamentales de la monografía de grado titulada Condominios, modelo de organización administrativa, que fue realizada con la intención de proponer nuevos mecanismos para elevar la calidad de vida de los habitantes de las grandes ciudades colombianas, quienes se enfrentan cada día con los problemas de inseguridad, contaminación ambiental, salubridad y dificultades de tráfico, entre otros. Se utilizó la bibliografía jurídica, ambiental y social que enmarca a los condominios, la experiencia de administradores y habitantes, y los conocimientos gerenciales para el desarrollo de un modelo en que la calidad y el factor humano son los pilares fundamentales. De allí en adelante se planteó un sendero para la planificación de los recursos físico, tecnológico, financiero y ambiental.

MODELO MULTIDIMENSIONAL

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Alexis Cedeño Trujillo

2006-04-01

Full Text Available

Data Warehousing, es una tecnología para el almacenamiento de grandes volúmenes de datos en una amplia perspectiva de tiempo para el soporte a la toma de decisiones. Debido a su orientación analítica, impone un procesamiento distinto al de los sistemas operacionales y requiere de un diseño de base de datos más cercano a la visión de los usuarios finales, permitiendo que sea más fácil la recuperación de información y la navegación. Este diseño de base de datos se conoce como modelo multidimensional, este artículo, abordará sus características principales.

Un modelo de redes neuronales para complementariedad no lineal

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Favián Arenas

2016-01-01

Full Text Available En este artí ulo presentamos un modelo de red neuronal para resolver el problema de omplementariedad no lineal. Para ello, reformulamos este problema omo uno de minimiza ión sin restri iones usando una familia uniparamétri a de fun iones de omplementariedad. Demostramos resultados de existen ia y onvergen ia de la traye toria de la red neuronal, así omo resultados de estabilidad en el sentido de Lyapunov, estabilidad asintóti a y exponen ial. Además, presentamos resultados numéri os preliminares que ilustran un buen desempeño prá ti o del modelo.

Spots educativos : un modelo de evaluación creativa

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Jorge Montalvo-Castro

2010-03-01

Full Text Available En esta investigación se precisan las semejanzas y diferencias entre los spots comerciales, sociales y educativos. Se analizan el problema de la eficacia de los spots y el papel de la creatividad. Además, se plantea la necesidad de contar con un modelo apropiado de evaluación de spots educativos que tome en cuenta ciertos principios de la teoría del aprendizaje significativo de David Ausubel. Finalmente, se diseña y propone un modelo de evaluación creativa —tipo lista de cotejo— que es sometido a una prueba experimental y cuyos resultados apoyan el planteamiento.

Modelo de simulación de sistemas de drenaje operados por bombeo

OpenAIRE

Sánchez Bribiesca, José L.; Fuentes Mariles, Óscar Arturo; Gràcia Sabaté, Francesc Xavier

1994-01-01

Se describe un modelo matemático que simula el funcionamiento de sistemas de drenaje operados por bombeo teniendo en cuenta la forma de trabajo de las bombas, según sus curvas de operación y el flujo transitorio en los conductos del sistema. Se comentan las posibles formas de utilizar el modelo en la solución de algunos problemas.

Dos modelos de interpretación: la indeterminación de la traducción en quine y el argumento modelo teorético de Putnam

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Carlos E. Caorsi

2013-06-01

Full Text Available Las tesis de la indeterminación de Quine establecen que las condiciones de verdad de una oración sub-determinan la referencia de los términos que ocurren en la misma. La cuestión es ¿cuál es el alcance de esa sub-determinación? En Reason, Truth and History Putnam señala que la su-determinación es mayor de lo que podría suponerse a partir de los argumentos de Quine y se propone, con su "argumento modelo teorético", prolongar radicalmenteestos resultados. En este artículo pretendo mostrar que el argumento modelo teorético de Putnam no es una mera prolongación de los resultados de Quine, sino que se trata de un argumento que supone un modelo de interpretación distinto del que subyace al argumento de este último. Si estoy en lo cierto, tendríamos en este caso dos modos de entender la interpretación y dependerá de qué modo la entendamos, el alcance que le demos a la sub-determinación de la referencia por los valores veritativos. Considero, por lo tanto, que el argumento de Putnam, si bien radicaliza las conclusiones de Quine, lo hace introduciendo un modelo de interpretación diferente al que es desarrollado en Word and Object.

OFERTA Y DEMANDA: UN MODELO MATEMÁTICO CON ECUACIONES DIFERENCIALES

OpenAIRE

Hernán Alberto Escobar

2010-01-01

Se presentan inicialmente unas ideas relacionadas con los modelos matemáticos en general, para luego enfocarse en uno muy concreto: el que utiliza como insumo básico las ecuaciones diferenciales ordinarias (EDOs). Dado que el modelo de oferta y demanda, utiliza para su explicación matemática y económica, las ecuaciones diferenciales lineales, se lleva a cabo una explicación de cómo obtener una solución analítica y gráfica de dichas ecuaciones. Posteriormente, se explica con detalle los elemen...

Metadecisão no modelo de gestão toyotista

OpenAIRE

Torres Júnior,Alvair Silveira

2010-01-01

O processo decisório no modelo de produção enxuta aparece como um fator pouco explorado na literatura. Os elementos que compõem o processo decisório aparecem marginalmente quando se discutem fatores como just-in-time, as parcerias com fornecedores, o desenvolvimento de produtos e a qualidade embutida no processo. O objetivo desta pesquisa é explorar como o processo decisório se apresenta no modelo de produção enxuta. Foram desenvolvidas entrevistas em profundidade com três ex-executivos do pr...

Modelo de costos para bases de datos en memoria principal

OpenAIRE

Martí, José Luis; Brand, Horst H. von

2002-01-01

El modelo de costos de un optimizador de consultas es un componente esencial de cualquier sistema administrador de bases de datos y, en especial, para un sistema basado en la memoria principal, en el cual los factores de costos son mucho más, en número y complejidad, que aquéllos usados por los tradicionales sistemas basados en el disco. El presente trabajo ejemplifica una propuesta destinada a plantear un modelo de costos para tal entorno, la que se basa en expresiones genéricas construidas ...

EL ACTO PEDAGÓGICO Y EL MODELO PEDAGÓGICO INSTITUCIONAL

Directory of Open Access Journals (Sweden)

Gustavo Alberto Barajas

2013-12-01

Full Text Available Este artículo muestra la importancia del acto pedagógico como escenario de aprendizaje donde el estudiante es el protagonista de su proceso de formación integral y donde el docente lleva a cabo su ejercicio de enseñanza en concordancia con el modelo pedagógico de la institución; además, se expone la relación entre el modelo pedagógico y el Proyecto Educativo Institucional (PEI como centro de partida para lograr objetivos y metas institucionales.

MODELO DE CLASIFICACIÓN DE OPINIONES SUBJETIVAS EN REDES SOCIALES

OpenAIRE

Tapia Perales, Miluska Rosangela; Universidad Señor de Sipán; Ruiz Montalvo, Osmar Niels; Universidad Señor de Sipán; Chirinos Mundaca, Carlos Alberto; Universidad Señor de Sipán

2015-01-01

El proyecto “modelo de clasificación de opiniones subjetivas en redes sociales”, aplica técnicas de Minería de datos para interpretar la opinión subjetiva (favorable o desfavorable) de los usuarios en las redes sociales que realizan en su actividad cotidiana (publicaciones) para analizar tendencias de un determinado producto, servicio o persona que sirva para la aplicación de marketing a fin de generar ventajas competitivas haciendo el uso de la analítica en la web 2.0.  El Modelo usa técnica...

Propuesta de modelo intraemprendedor para la innovación en organizaciones perdurables.

Directory of Open Access Journals (Sweden)

Manuel Alfonso Garzón Castrillón

2010-05-01

Full Text Available Esta ponencia desarrolla una propuesta de modelo teórico intraemprendedor, para la innovación en organizaciones que perduran, con resultados de tres investigaciones. Contempla dos estudios experimentales en México y Colombia, respectivamente, en grandes organizaciones, y un estudio exploratorio con directivos de Pymes en Bogotá D.C. Esta propuesta de modelo intenta predecir la incidencia de las variables independientes “características organizacionales”, “características individuales” y “creación del contexto organizacional”, sobre la variable dependiente “innovación”. Es un avance del libro titulado “Propuesta de modelo intraemprendedor para la innovación”, que actualmente se encuentra en revisión de pares internacionales para su publicación.

Estudio de soluciones metálicas. (I Aplicabilidad y limitaciones de algunos modelos termodinámicos

Directory of Open Access Journals (Sweden)

Jaime Valderrama N.

2009-07-01

Full Text Available Se presentan y analizan las características centrales de los modelos termodinámicos energéticos basados en la interacción por pares entre un átomo y sus próximos vecinos. Se discute la aplicabilidad de estos modelos a sistemas metálicos binarios. Se concluye sugiriendo posibles alternativas para el refinamiento de estos modelos.

Un modelo explicativo de resiliencia en jovenes y adolescentes Um modelo explicativo de resiliência em jovens e adolescentes An explanatory model of resilience in youth and adolescents

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Alicia Omar

2011-06-01

Full Text Available La resiliencia ha sido definida como la capacidad para superar y salir fortalecido de las adversidades. Esta capacidad es evolutiva y es influenciada por factores protectivos, tanto personales como ambientales. Si bien muchos de estos factores han sido identificados, poco se sabe acerca de las complejas interacciones entre ellos y la forma que contribuyen al desarrollo de la resiliencia. Con base en la evidencia científica más reciente, el objetivo del presente trabajo fue desarrollar un modelo explicativo de la resiliencia en jóvenes y adolescentes. Cada variable introducida en el modelo asienta sus bases en la evidencia teórica o empírica publicada. Por la naturaleza de las variables incluidas (optimismo, sentido del humor, emociones positivas, bienestar, inteligencia emocional, el modelo propuesto se enmarca dentro de los lineamientos de la Psicología Positiva. Se ofrecen sugerencias teóricas, metodológicas y epistemológicas para poner a prueba el modelo..Tem-se definido resiliência como a capacidade de superar as adversidades e sair delas mais fortalecido. Esta capacidade é evolutiva e é influenciada por fatores de proteção tanto pessoal como ambiental. Embora muitos desses fatores tenham sido identificados, pouco se sabe sobre as complexas interações entre eles e a maneira como contribuem para o desenvolvimento da resiliência. O bjetivo destes trabalho foi desenvolver, com base nos últimos dados científicos, um modelo explicativo da resiliência em jovens e adolescentes. Cada variável introduzida no modelo está enraizada na prova teórica ou empírica publicada. Pela natureza das variáveis incluídas (otimismo, senso de humor, emoções positivas, bem-estar e inteligência emocional, o modelo proposto enquadra-se nas diretrizes da Psicologia Positiva. Sugestões teóricas, metodológicas e epistemológicas são oferecidas para testar o modelo.Resilience has been defined as the ability to overcome and emerge stronger

Sobre un modelo de Holthausen para la empresa competitiva bajo incertidumbre en el precio

OpenAIRE

Álvarez López, A. A.

1999-01-01

El modelo presentado por HOLTHAUSEN (1979) amplía el modelo original de SANDMO (1971) para una empresa competitiva bajo incertidumbre en el precio y aversión al riesgo. La aportación esencial de HOLTHAUSEN es la de considerar que existe un mercado de futuros para el bien que la empresa produce, lo que causa que el comportamiento de ésta frente al riesgo sea diferente. En este trabajo planteamos el problema de decisión de la empresa del modelo de HOLTHAUSEN como un problema de optimización de ...

Um estudo dos principais modelos de transações em banco de dados móveis e uma proposta diferenciada do modelo pro-motion

OpenAIRE

Silva, Edson Carlos da

2003-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação. Este trabalho apresenta um estudo sobre as principais arquiteturas e modelos de transações móveis. Faz uma revisão sobre os principais problemas encontrados no ambiente móvel, suas características, modelos e propriedades da transação, bem com uma revisão sobre as transações convencionais dos Sistemas Gerenciadores de Banco de Dados Distribuídos # SGBDD # ...

Proposta de um modelo de maturidade para sítios de governo eletrônico

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Rafael de Mello Lechakoski

2015-09-01

Full Text Available Introdução: Tendo em vista a crescente utilização da tecnologia da informação - em especial a internet - pelo governo como meio de interação com cidadãos, a investigação apresenta estudo bibliográfico acerca de modelos de maturidade para governo eletrônico, abordando os temas de serviços públicos e de maturidade tanto para conceituar a Maturidade em Governo Eletrônico como para propor um modelo de maturidade para sítios de governo eletrônico. Método: Para atendimento ao propósito da pesquisa efetuou-se coleta intencional de 24 modelos de maturidade para governo eletrônico e se procedeu a análise comparativa entre eles verificando-se suas limitações em relação aos serviços prestados; à acessibilidade; à usabilidade e à integração com redes sociais, considerando-se a realidade brasileira e os requisitos previstos no Modelo de Acessibilidade em Governo Eletrônico (e-MAG. Resultados: Propõe-se um modelo de maturidade para sítios de governo eletrônico baseado na convergência dos modelos analisados, o qual é composto por quatro estágios voltados à avaliação de requisitos de serviços, acessibilidade, usabilidade e redes sociais. Diferentemente dos demais analisados, o modelo apresentado considera tanto as recomendações de acessibilidade para internet do World Wide Web Consortium (W3C, como aquelas de acessibilidade e usabilidade do governo brasileiro (e-MAG. Em cada estágio proposto apresentam-se exemplos de requisitos que podem ser avaliados e, potencialmente, transformados em indicadores. Conclusão: A utilização de um modelo para avaliar a maturidade em sítios de governo eletrônico evidencia a situação em que o sítio se encontra em relação ao que é esperado em cada estágio e qual é a linha conceitual de evolução dentro do modelo de maturidade, que reflete em melhorias a seus usuários ou cidadãos de maneira geral.

Deformable meshes for medical image segmentation accurate automatic segmentation of anatomical structures

CERN Document Server

Kainmueller, Dagmar

2014-01-01

? Segmentation of anatomical structures in medical image data is an essential task in clinical practice. Dagmar Kainmueller introduces methods for accurate fully automatic segmentation of anatomical structures in 3D medical image data. The author's core methodological contribution is a novel deformation model that overcomes limitations of state-of-the-art Deformable Surface approaches, hence allowing for accurate segmentation of tip- and ridge-shaped features of anatomical structures. As for practical contributions, she proposes application-specific segmentation pipelines for a range of anatom

Modelos para la investigación con embriones

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López de la Vieja, M.ª Teresa

2013-10-01

Full Text Available Different models to approach research on embryos are relevant in theory and in practice. The Spanish Act of 2007 could exemplify the possibility of regulating research on human pre-embryos and, at the same time, establishing clear requirements to accept projects and practices. On the one hand, the gradualist model usually considers different levels of development and, for this reason, different levels of protection of human life. On the other hand, the nongradualist model rejects research on embryos, since it defends the protection of human life from the very beginning and in general. Disagreements about the topic and different laws only prove that it is still a difficult issue in European and other countries. The article argues that, in plural societies, respect for all perspectives and models requires to regulate biomedical research rather than prohibiting certain practices that are coherent with a specific idea of human life.Los modelos son relevantes para la teoría y para la práctica de la investigación con embriones. La Ley del año 2007, de investigación biomédica, ejemplifica la posibilidad de regular este tipo de investigación y, al mismo tiempo, establecer condiciones para autorizar proyectos y prácticas. Por un lado, el modelo gradualista considera que el desarrollo tiene diferentes etapas y, por lo mismo, ha de tener distintos grados de protección. Por otro, el modelo no gradualista rechaza este tipo de investigación, al defender la protección de la vida humana, desde sus inicios. Los desacuerdos en torno al tema demuestran que se trata de una cuestión que sigue siendo polémica, en la Unión Europea y en otros países. El artículo defiende que, en sociedades pluralistas, el respeto por todos los enfoques y modelos llevará a regular la investigación biomédica, no a prohibir prácticas acordes con una determinada noción de la vida humana.

Modelos de equações estruturais em psicologia: conceitos e aplicações

Directory of Open Access Journals (Sweden)

Ronaldo Pilati

Full Text Available O debate sobre procedimentos e técnicas de tratamento de dados é relevante para o contexto de produção e avanço do conhecimento em várias áreas do saber. Os Modelos de Equações Estruturais são um conjunto de técnicas de tratamento de dados que têm recebido grande atenção de pesquisadores, especialmente nos últimos 10 anos. Esse procedimento de tratamento de dados possui suas raízes relacionadas a distintas áreas do conhecimento: a biometria, a econometria e a psicometria. Como conseqüência de suas peculiaridades, o relato científico em Modelos de Equações Estruturais deve considerar vários aspectos relevantes, como a definição teórica do modelo a ser testado, a especificação e identificação do modelo, além de aspectos de estimação e mensuração dos índices de adequação. Vários desses elementos são apresentados e discutidos no presente artigo focando-se nas possibilidades de aplicação na Psicologia e em ciências correlatas. Perspectivas futuras e limitações dos Modelos de Equações Estruturais são discutidas.

Modelos de Personalidad de marca: una descripción de 1997 a 2015

Directory of Open Access Journals (Sweden)

Manuel Escobar Farfán

2016-12-01

Full Text Available La personalidad de marca ha sido estudiada y complementada en las últimas dos décadas. Actualmente entrega aspectos de caracterización y diferenciación entre una marca y otra. Por este motivo, Jennifer Aaker (1997 propone un modelo en el contexto de Estados Unidos, mediante una escala generalizable y confiable, señalando que existen cinco dimensiones de personalidad: competencia, rudeza, sinceridad, sofisticación y emocionalidad. Sin embargo, existe evidencia en la literatura que el modelo puede ser replicado en diversos contextos culturales y empresariales, como también constan críticas que señalan que no es posible duplicarlo en toda circunstancia, ya que la percepción y gustos de los consumidores pueden variar entre un país y otro. Por este motivo diferentes investigadores han propuesto nuevos modelos de personalidad, señalando que existen dimensiones acordes al estudio. En este contexto, en la presente investigación se realiza una revisión teórica y evolutiva de los modelos desde 1997 a 2015, conceptualizando la definición de marca y personalidad. Como conclusión en este estudio, el modelo de Aaker se encuentra presente en la mayoría de los estudios analizados, ratificando el respaldo de la literatura a las cinco dimensiones de personalidad de marca.

Propuesta de mejoramiento del modelo de productividad laboral y su aplicación en la empresa Tubometales Cuernu Ltda.

OpenAIRE

Correcha Saavedra, Luis Felipe; Gutiérrez Forero, Manolo Andrés

2013-01-01

El trabajo contiene la propuesta de mejoramiento del modelo de productividad laboral y su aplicación en la empresa Tubometales Cuernu Ltda., a partir de la investigación y definición de los siguientes modelos de productividad: modelo de productividad total, modelo de productividad del valor agregado (MPVA) y el modelo de productividad basado en prácticas de gestión humana. Por otra parte de definen los métodos Justo a tiempo (Just in Time), 5´s, Six Sigma y el método de mantenimiento producti...

Reformas estructurales: modelos difíciles de armar

Directory of Open Access Journals (Sweden)

Jaime Alberto Rendón Acevedo

2005-01-01

Full Text Available Un balance crítico de los modelos de desarrollo con los que se ha pretendido entregarle a América Latina mejores condiciones de crecimiento y equidad. Desde el modelo de sustitución de importaciones hasta las reformas estructurales de segunda generación, propias del final de la década de 1990, el continente ha debido enfrentar programas de ajuste macroeconómico, político y social que muy poco han contribuido a subsanar las difíciles condiciones estructu rales existentes. Sin embargo, quedan retos grandes hacia los años venideros, de tal manera que se pueda lograr la viabilidad económica y social de un continente plagado de frustraciones, retos que se habrán de enfrentar con gran responsabilidad y creatividad.

Speaker segmentation and clustering

OpenAIRE

Kotti, M; Moschou, V; Kotropoulos, C

2008-01-01

07.08.13 KB. Ok to add the accepted version to Spiral, Elsevier says ok whlile mandate not enforced. This survey focuses on two challenging speech processing topics, namely: speaker segmentation and speaker clustering. Speaker segmentation aims at finding speaker change points in an audio stream, whereas speaker clustering aims at grouping speech segments based on speaker characteristics. Model-based, metric-based, and hybrid speaker segmentation algorithms are reviewed. Concerning speaker...

Modelaje matemático del modelo neurobiológico de las adicciones

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Miguel Angel Mendoza

2016-06-01

Full Text Available Introducción: la adicción es considerada una enfermedad del sistema nervioso central que consta de tres etapas: intoxicación, abstinencia y craving. El modelo neurobiológico de las adicciones propuesto por Volkow y colaboradores (2003 incluye los estados de control, memoria, motivación y recompensa, sin embargo, con el fin de generar una solución explícita y universal a dicha enfermedad es necesario matematizar los modelos teóricos. Objetivo: proponer y desarrollar la matematización de un modelo estocástico usando Cadenas de Markov en el fenómeno del consumo de sustancias psicoactivas y las adicciones. Método: matematización de un modelo estocástico usando Cadenas de Markov y ecuaciones diferenciales. Resultados: utilizando Cadenas de Markov, se compararon los modelos de dos cerebros, uno sano (de una persona no consumidora de sustancias psicoactivas y otro perteneciente a una persona adicta, y por medio de las probabilidades de transición se observaron las diferencias entre ambos. Se utilizaron ecuaciones diferenciales para estimar el tiempo del efecto de una droga en el cuerpo y, en combinación con ecuaciones trigonométricas, se buscó la mejor función para estimar las probabilidades de continuar con una adicción y una recaída. Discusión y conclusiones: el modelaje matemático obtenido nos indica que el modelo neurobiológico de las adicciones puede ser representado por una Cadena de Markov no homogénea. En el caso de un cerebro sano se puede pasar con igual probabilidad (p = 1/3 de un estado a otro, mientras que en el caso de una persona adicta, las probabilidades de transición dependen del tiempo, el tipo de droga, la dosis y la vía de administración.

Modelo Teórico Integrado de Gamificación en Ambientes E-Learning (E-MIGA

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Angel Torres-Toukoumidis

2018-01-01

Full Text Available La presencia de elementos lúdicos en el contexto educativo, específicamente en la modalidad de formación E-learning, demuestra que la incorporación de la gamificación sistematiza la experiencia del usuario en base a parámetros relacionados con los juegos. Este artículo presenta la integración de dos modelos conceptuales de gamificación extraídos de la revisión literaria publicada entre el 2012 y el 2015, validando cada una de las dimensiones e indicadores mediante un estudio Delphi con expertos en pedagogía y diseño de juegos. Posteriormente, se exhiben los resultados cualitativos de la aplicación del modelo en 6 aplicaciones móviles educativas analizadas durante 7 meses (junio 2015- enero 2016 manifestando la correlación de los modelos seleccionados según los criterios de idoneidad y pertinencia. En definitiva, el siguiente modelo construye una vía de conexión entre la base teórica y el análisis empírico de la gamificación con el fin de sobreponerse a los retos de la educación E-learning en el siglo XXI teniendo como última instancia la transposición del modelo teórico a un modelo de utilidad cuantitativo al servicio de futuras investigaciones.

Segmentation of the Infant Food Market

OpenAIRE

Hrůzová, Daniela

2015-01-01

The theoretical part covers general market segmentation, namely the marketing importance of differences among consumers, the essence of market segmentation, its main conditions and the process of segmentation, which consists of four consecutive phases - defining the market, determining important criteria, uncovering segments and developing segment profiles. The segmentation criteria, segmentation approaches, methods and techniques for the process of market segmentation are also described in t...

Um novo modelo de previsão de demanda para inovações radicais

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Donald Neumann

2014-09-01

Full Text Available Este trabalho apresenta um novo modelo para a previsão de demanda de inovações radicais baseada em simulação de Dinâmica de Sistemas que combina conceitos do modelo de difusão de Bass e do modelo de escolha discreta. Diferentemente de outras abordagens existentes, esta proposta permite estimar não somente a fatia de mercado do produto, mas também seu comportamento no tempo (timing, a partir das preferências individuais do consumidor e das forças que as influenciam. O modelo proposto pode ser facilmente parametrizado através da Conjoint Analysis e foi testado em escala real no mercado alemão de carros elétricos. Os resultados obtidos colocam em evidência o potencial da abordagem proposta, auxiliando na compreensão dos principais fatores na escolha desse produto.

Pancreas and cyst segmentation

Science.gov (United States)

Dmitriev, Konstantin; Gutenko, Ievgeniia; Nadeem, Saad; Kaufman, Arie

2016-03-01

Accurate segmentation of abdominal organs from medical images is an essential part of surgical planning and computer-aided disease diagnosis. Many existing algorithms are specialized for the segmentation of healthy organs. Cystic pancreas segmentation is especially challenging due to its low contrast boundaries, variability in shape, location and the stage of the pancreatic cancer. We present a semi-automatic segmentation algorithm for pancreata with cysts. In contrast to existing automatic segmentation approaches for healthy pancreas segmentation which are amenable to atlas/statistical shape approaches, a pancreas with cysts can have even higher variability with respect to the shape of the pancreas due to the size and shape of the cyst(s). Hence, fine results are better attained with semi-automatic steerable approaches. We use a novel combination of random walker and region growing approaches to delineate the boundaries of the pancreas and cysts with respective best Dice coefficients of 85.1% and 86.7%, and respective best volumetric overlap errors of 26.0% and 23.5%. Results show that the proposed algorithm for pancreas and pancreatic cyst segmentation is accurate and stable.

Phasing multi-segment undulators

International Nuclear Information System (INIS)

Chavanne, J.; Elleaume, P.; Vaerenbergh, P. Van

1996-01-01

An important issue in the manufacture of multi-segment undulators as a source of synchrotron radiation or as a free-electron laser (FEL) is the phasing between successive segments. The state of the art is briefly reviewed, after which a novel pure permanent magnet phasing section that is passive and does not require any current is presented. The phasing section allows the introduction of a 6 mm longitudinal gap between each segment, resulting in complete mechanical independence and reduced magnetic interaction between segments. The tolerance of the longitudinal positioning of one segment with respect to the next is found to be 2.8 times lower than that of conventional phasing. The spectrum at all gaps and useful harmonics is almost unchanged when compared with a single-segment undulator of the same total length. (au) 3 refs

FRAMEWORK FOR COMPARING SEGMENTATION ALGORITHMS

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G. Sithole

2015-05-01

Full Text Available The notion of a ‘Best’ segmentation does not exist. A segmentation algorithm is chosen based on the features it yields, the properties of the segments (point sets it generates, and the complexity of its algorithm. The segmentation is then assessed based on a variety of metrics such as homogeneity, heterogeneity, fragmentation, etc. Even after an algorithm is chosen its performance is still uncertain because the landscape/scenarios represented in a point cloud have a strong influence on the eventual segmentation. Thus selecting an appropriate segmentation algorithm is a process of trial and error. Automating the selection of segmentation algorithms and their parameters first requires methods to evaluate segmentations. Three common approaches for evaluating segmentation algorithms are ‘goodness methods’, ‘discrepancy methods’ and ‘benchmarks’. Benchmarks are considered the most comprehensive method of evaluation. This paper shortcomings in current benchmark methods are identified and a framework is proposed that permits both a visual and numerical evaluation of segmentations for different algorithms, algorithm parameters and evaluation metrics. The concept of the framework is demonstrated on a real point cloud. Current results are promising and suggest that it can be used to predict the performance of segmentation algorithms.

CFD modeling of a UV-A LED baffled flat-plate photoreactor for environment applications: a mining wastewater case.

Science.gov (United States)

Devia-Orjuela, John Steven; Betancourt-Buitrago, Luis Andrés; Machuca-Martinez, Fiderman

2018-06-02

The use of ultraviolet light in photoreactors for wastewater treatment has become popular as an alternative of known chemical oxidative substances. UV LED light represents cheaper, robust, and versatile alternative to traditional UV lamps. In this study, it was designed and evaluated a photoreactor with an approach of chemical fluid dynamics (CFD) and experimental validation. The evaluation consisted of (1) CFD velocity profile analysis, (2) characterization of the average light distribution with potassium ferrioxalate actinometry, (3) degradation of a typical recalcitrant metallic cyanocomplex Fe(CN) 6 3- , and (4) scavenger effect analysis in the photodegradation using potassium persulfate. Actinometrical essay concluded that the system was able to receive 1.93 μE/s. The reactor operated under turbulent regime and best result for Fe(CN) 6 3- degradation was obtained at 4 h of operation, using 5-W UV-A LEDs, with pH ~ 7 and 10 mM de S 2 O 8 2- . Baffled photoreactor demonstrated to be useful for this type of illumination and wastewater treatment.

MODELO MATEMÁTICO PARA EL PROCESO TÉRMICO DE PRODUCTOS CÁRNICOS DE GEOMETRÍA CILÍNDRICA

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DIANA ARBOLEDA

2010-01-01

Full Text Available El objetivo del trabajo fue desarrollar un modelo matemático que permita simular el comportamiento de la temperatura y la pérdida de peso en un producto cárnico con forma cilíndrica durante el proceso térmico. Para desarrollar el modelo se utilizó una forma geométrica similar a la del producto real la cual se dividió en volúmenes de control representados por cilindros concéntricos. Sobre este volumen de control se realizó un balance de masa y energía y se obtuvo el modelo propuesto en este trabajo, el cual fue validado con datos obtenidos de pruebas experimentales. Se obtuvo un modelo matemático que representa de manera precisa el comportamiento de la temperatura en varias posiciones a lo largo del radio del producto, sin embargo el modelo de pérdida de peso no exhibe la misma calidad debido a limitaciones en los instrumentos de medición. Los modelos se simularon en MATLAB ® utilizando la herramienta Simulink.

Why segmentation matters: experience-driven segmentation errors impair “morpheme” learning

Science.gov (United States)

Finn, Amy S.; Hudson Kam, Carla L.

2015-01-01

We ask whether an adult learner’s knowledge of their native language impedes statistical learning in a new language beyond just word segmentation (as previously shown). In particular, we examine the impact of native-language word-form phonotactics on learners’ ability to segment words into their component morphemes and learn phonologically triggered variation of morphemes. We find that learning is impaired when words and component morphemes are structured to conflict with a learner’s native-language phonotactic system, but not when native-language phonotactics do not conflict with morpheme boundaries in the artificial language. A learner’s native-language knowledge can therefore have a cascading impact affecting word segmentation and the morphological variation that relies upon proper segmentation. These results show that getting word segmentation right early in learning is deeply important for learning other aspects of language, even those (morphology) that are known to pose a great difficulty for adult language learners. PMID:25730305

IDENTIFICANDO OS MODELOS DIDÁTICOS DE UM GRUPO DE PROFESSORES DE QUÍMICA

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João Batista Santos Junior

Full Text Available Esta investigação visa a identificar os modelos didáticos de um grupo de professores de Química de escolas públicas e propõe uma meto dologia para a sua utilização como instrumento de reflexão do docente em relação às suas concepções acerca do processo de ensino e aprendiza gem. Para tal, foi solicitado aos professores que respondessem a um ques tionário baseado nas ideias de Garcia Pérez (2000. Os resultados obtidos apontam que os professores combinam características diferentes dos modelos didáticos para formar um modelo didático eclético (GUIMARÃES, ECHEVERRÍA & MORAES, 2006. Esses modelos ecléticos encerram características antagônicas e podem indicar a necessi dade de aprofundamento da reflexão dos docentes sobre as suas concep ções. É proposta uma metodologia para a utilização do instrumento de investigação do pensamento do professor.

Segment-Tube: Spatio-Temporal Action Localization in Untrimmed Videos with Per-Frame Segmentation

OpenAIRE

Le Wang; Xuhuan Duan; Qilin Zhang; Zhenxing Niu; Gang Hua; Nanning Zheng

2018-01-01

Inspired by the recent spatio-temporal action localization efforts with tubelets (sequences of bounding boxes), we present a new spatio-temporal action localization detector Segment-tube, which consists of sequences of per-frame segmentation masks. The proposed Segment-tube detector can temporally pinpoint the starting/ending frame of each action category in the presence of preceding/subsequent interference actions in untrimmed videos. Simultaneously, the Segment-tube detector produces per-fr...

MODELOS COGNITIVOS, OPERACIONES COGNITIVAS Y USOS FIGURADOS DEL LENGUAJE

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Francisco José Ruiz de Mendoza Ibáñez

2012-06-01

Full Text Available El presente artículo está dedicado al estudio de los diferentes mecanismos cognitivos que, al operar sobre diferentes modelos cognitivos (ya sea en solitario o en combinación, dan origen a una serie de efectos de significado en el plano comunicativo. Dichos efectos constituyen lo que normalmente se conoce como usos figurados del lenguaje, tales como la ironía, la paradoja, la hipérbole, etc. Con este propósito, presentamos una taxonomía tanto de modelos como de operaciones cognitivas, atendiendo a varios criterios de clasificación. Además, proponemos una serie de principios reguladores que constriñen la actuación de las operaciones cognitivas.

Modelos cognitivos, operaciones cognitivas y usos figurados del lenguaje

Directory of Open Access Journals (Sweden)

Francisco José Ruiz de Mendoza Ibáñez

2012-01-01

Full Text Available El presente artículo está dedicado al estudio de los diferentes mecanismos cognitivos que, al operar sobre diferentes modelos cognitivos (ya sea en solitario o en combinación, dan origen a una serie de efectos de significado en el plano comunicativo. Dichos efectos constituyen lo que normalmente se conoce como usos figurados del lenguaje, tales como la ironía, la paradoja, la hipérbole, etc. Con este propósito, presentamos una taxonomía tanto de modelos como de operaciones cognitivas, atendiendo a varios criterios de clasificación. Además, proponemos una serie de principios reguladores que constriñen la actuación de las operaciones cognitivas.

Reducción de costo total de inventario aplicando un modelo de control de inventario del tipo (s,S).

OpenAIRE

Matos Quispe, Cesar Anibal; Matos Quispe, Cesar Anibal; Matos Quispe, Cesar Anibal

2012-01-01

El presente informe de suficiencia propone un modelo de control de inventario para minimizar los costos totales de inventario, aplicando una política de inventario de tipo (s, S) que es un modelo de control de inventario de clase estocástica. Explica cómo se desarrolla el modelo mediante el uso de la simulación Monte Cario tanto para simular el modelo de inventario, así como también la metodología de optimización para obtener los valores de decisión. Para el modelo de simulación se conside...

Un modelo para facilitar el cambio en la escuela: el modelo CBAM

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José M. CORONEL LLAMAS

2009-11-01

Full Text Available RESUMEN: En este artículo se describen los rasgos generales de un modelo para conocer el modo en que los centros pueden hacer frente a diversas propuestas de innovación, concretamente, el modelo CBAM. Nos detenemos en el marco conceptual que lo sustenta y presentamos sus dimensiones tanto diagnósticas (Estados de Preocupación, Niveles de Uso y Configuraciones de la Innovación, como prescriptivas (Anatomía de Intervenciones y Taxonomía de Intervenciones, como herramientas sobre las que trabajar con procesos de innovación educativa.ABSTRACT: This paper describes the general features of a model with which it may be possible to know how schools can face up to different innovative proposals; namely the CBAM model. We examine the conceptual framework underlying the model and present its diagnostic (States of Concern, Levéis of Use and Innovation Configurations and prescriptive (Anatomy and Taxonomy of Interventions dimensions as tools on which to work with processes of educational innovation.RÉSUMÉ: Cet article décrit les principaux traits généraux d'un modele -le modele CBAM- en vue de savoir la facón dont les centres peuvent faire face a diverses propositions d'innovation. Nous nous centrons sur le cadre conceptuel qui compose ce modele et nous présentons ses diverses dimensions: dimensions diagnostiques (Etats de Préoccupation, Niveaux d'usage et Configurations de Hnnovation ou dimensions prescriptives (Anatomie d'interventions et Taxonomie d'Interventions. Ces deux dimensiones constituent l'outillage nécessaire pour travailler sur les plans de l'innovation éducative.

Las fuentes del desempleo en Colombia: un examen a partir de un modelo SVEC

OpenAIRE

Enrique López Enciso; Martha Misas Arango

2006-01-01

En este artículo se analizan las fuentes del desempleo en Colombia en el marco de un modelo estructural de corrección de errores (SVEC). Con este propósito se estima un modelo de corrección de errores. El análisis de cointegración muestra la existencia de una relación de largo plazo entre la productividad, el empleo, el desempleo, la tasa real de cambio y el salario real. Con base en la forma reducida del modelo de corrección de errores se identifican los shocks estructurales y se determina s...

Estilos de aprendizaje y actividades polifásicas : modelo EAAP

OpenAIRE

Lago, Baldomero; Colvin, Lilian; Cacheiro González, María Luz

2008-01-01

En esta comunicación [url: caceres2008) se parte de una fundamentación sobre la utilidad pedagógica de la aplicación de teoría sobre los estilos de aprendizaje en la que se basa el CHAEA [url: chaea): Activo, Reflexivo, Teórico y Pragmático a la hora de seleccionar las estrategias de enseñanza-aprendizaje. Este trabajo propone un modelo para la selección o creaclon de actividades didácticas basadas en los estilos de aprendizaje: Modelo EAAP-Estilos de Aprendizaje y Actividades Polif...

Numerical simulation of flow field in shellside of heat exchanger in nuclear power plant

International Nuclear Information System (INIS)

Wang Xinliang; Qiu Jinrong; Gong Zili

2010-01-01

Heat exchanger is the important equipment of nuclear power plant. Numerical simulation can give the detail information inside the heat exchange, and has been an effective research method. The geometric structure of shell-and-tube heat exchanger is very complex and it is difficult to simulate the whole flow field presently. According to the structure characteristics of the heat exchanger, a periodic whole-section calculation model was presented. The numerical simulation of flow field in shellside of heat exchange of a nuclear power plant was done by using this model. The results of simulation show that heat transfer in the periodic section of the heat exchange is uniform, the heat transfer is enhanced by using baffles in heat exchange, and frictional resistance is primary from the effect of segmental baffles. (authors)

Various methods to improve heat transfer in exchangers

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Pavel Zitek

2015-01-01

Full Text Available The University of West Bohemia in Pilsen (Department of Power System Engineering is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors. For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production. In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

Consideraciones sobre la categoría epistemológica de modelo

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Adriana Patricia Gallego Torres

2012-04-01

Full Text Available En este artículo la autora presenta las diversas concepciones acerca de la categoría epistemológica de modelo científico. Intenta demostrar que esta categoría sigue estando afincada en el estatuto científico de la física, por lo que emplear la de teoría científica o la de modelo sin unas especificaciones desde aproximaciones históricas no aporta un cambio significativo en la mirada habitual sobre el estatuto científico de las diferentes ciencias de la naturaleza, especialmente si las conceptualizaciones al respecto siguen teniendo como matriz la física. Tampoco contribuye a una didáctica de la modelización o modelación, esto es, la de la construcción de modelos científicos en el aula, como se demuestra en los párrafos de este artículo.

LUCHANDO INFRUCTUOSAMENTE CONTRA LA HIDRA: UN MODELO SENCILLO DEL NARCOTRÁFICO

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Carlos Humberto Ortiz

2002-12-01

Full Text Available En este artículo se presenta un modelo sencillo del narcotráfico que incorpora los riesgos de esta actividad. El modelo contribuye a explicar dos características notables del narcotráfico: la generación de ganancias extraordinarias y la gran capacidad de reproducción en condiciones de prohibición y represión. El modelo genera una relación directa entre la represión a la oferta -la estrategia dominante de lucha contra el narcotráfico- y las características mencionadasA simple model of drug trafficking, which embodies this activity risks, is shown in this paper. The model helps to explain two stylized facts of this activity: the generation of extraordinary profits and strong reproduction ability under prohibition and repression. The model creates a direct link between the repression of supply, which has been the dominant strategy in the fight against drug trafficking, and the mentioned facts.

Beneficios de utilizar modelos ad-hoc de gestión de inventarios en presencia de flujos de retorno

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Juan Pedro Sepúlveda Rojas

2010-01-01

Full Text Available En este trabajo se analiza el impacto de la logística reversa en los modelos de gestión de inventarios a través del análisis de las implicancias y extensiones de algunos modelos estudiados en la literatura. A través de experimentación con modelos de inventario determinísticos encontramos que en gran parten de los escenarios estudiados, los costos de utilizar modelos clásicos de gestión de inventarios son superiores a modelos que toman en cuenta los flujos de retorno. Solo en casos muy particulares en donde el costo de mantención de stocks en el taller de reparables era muy elevado, se observaba la conveniencia del uso de los modelos tradicionales en detrimento de los que consideran flujos de retorno. Se puede observar además que no existen comparaciones cuantitativas entre una gestión tradicional de inventarios y una que considere los flujos de retorno.

Precisão na montagem em articulador em função do tipo de gesso e tratamento do modelo

OpenAIRE

Lopes, Luis Artur; Cezero, Leonardo; Mezzomo, Élio; Suzuki, Roberto

2010-01-01

O objetivo do presente estudo foi investigar a influência do tipo de gesso na precisão da montagem de modelos superiores secos e hidratados em articulador semi-ajustável. Neste estudo, 36 modelos de gesso pedra foram confeccionados e montados em articulador segundo as condições de seis grupos experimentais e de acordo com o tipo de gesso e o tempo de hidratação dos modelos: Grupo 1: modelos secos fixados com gesso pedra; Grupo 2: modelos secos f...

Modelos de regressão com platô na estimativa do tamanho de parcelas em experimento de conservação in vitro de maracujazeiro Using of regression plateau models in estimation of plot sizes for experiments with passion fruit

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Ana Patricia Bastos Peixoto

2011-11-01

Full Text Available A determinação do tamanho de parcela é uma prática pertinente ao planejamento experimental e sua caracterização otimizada, em conjunto com o controle do material experimental, permite a obtenção de resultados com maior precisão e qualidade. Neste trabalho, determinou-se o tamanho de parcelas para experimentos de conservação in vitro de maracujazeiro, em dez ensaios de uniformidade com a espécie Passiflora Giberti N. E. Brown, utilizando-se o modelo de regressão linear segmentado com platô e o modelo de regressão quadrática segmentado com platô, que utilizam a técnica de resposta com platô a modelos que possuam mínimo. Os ensaios de uniformidade foram oriundos de experimento conduzido no delineamento inteiramente casualizado, com 20 unidades básicas (ub, e os tratamentos dispostos em esquema fatorial com três concentrações de sacarose, três concentrações de sorbitol e uma testemunha. A coleta dos dados foi realizada aos 60 dias após a incubação, medindo-se o comprimento das brotações. Os tamanhos de parcelas variaram com o método utilizado, encontrando-se parcelas formadas por seis explantes pelo modelo da regressão linear segmentado com platô e de dez explantes pelo modelo de regressão quadrática segmentado com platô.The determination of the plot size is a practical question to the experimental design, and its characterization in an optimized way allows obtaining larger precision and quality results. This research aimed to determine the plot size in experiments in vitro that seek the passion fruit plant conservation in ten uniformity assays with the species Passiflora Giberti N. E. Brown. The tests of uniformity came from an experiment conducted in a completely randomized design with treatments in a factorial design with three concentrations of sucrose, three concentrations of sorbitol and a control. Each treatment was considered as a uniformity assay, with 20 basic units. The evaluations of the experiments

MODELO DE INCREMENTO PARA ÁRVORES SINGULARES – Nectandra megapotamica (Spreng. Mez

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Peter Spathelf

2004-05-01

Full Text Available No setor florestal, os modelos de crescimento e incremento são utilizados para predizer o crescimento de uma árvore, de um povoamento ou de uma floresta. Nas florestas heterogêneas e de várias idades do Rio Grande do Sul, modelos de árvores individuais são apropriados. O presente trabalho foi estabelecido para contribuir para a formulação de um modelo de incremento de uma espécie da Floresta Estacional Decidual do Rio Grande do Sul: a Nectandra megapotamica. A coleta de dados foi realizada no distrito de Vale Vêneto, próximo a Santa Maria, nos anos de 1994 e 1997. A vegetação foi classificada em diferentes estágios sucessionais e nesses estágios, instaladas unidades amostrais permanentes (uap. Em cada uap, todas as árvores com DAP ≥ 5 cm foram identificadas, numeradas e medidas. Adicionalmente, a posição sociológica e variáveis do sítio foram estimadas. Em cada uap, calcularam-se a área basal individual, área basal por ha e área basal das árvores maiores que a concorrida (BAL. Em seguida, estabeleceram-se funções de crescimento utilizando o procedimento stepwise. A fórmula geral do modelo é: Incremento (g/ano = f (Dimensões, Concorrência, Sítio. O melhor modelo para Nectandra megapotamica é: ICA = 0,002084 + 0,000001039 x DAP² – 0,0003498 x Degradação – 0,000375 x P.S. – 0,00000904 x Pedregosidade – 0,0000103 x BAL.

Diseno de un Modelo de Franquicia para Comercializar Calzado en PYMES

OpenAIRE

Freire Valencia, Elga Verónica

2015-01-01

1. Introducción.-- 2. Planteamiento de la Propuesta de Trabajo.-- 3. Marco Teórico.-- 4. Metodología.-- 5. Resultados.-- 6. Conclusiones y Recomendaciones El presente trabajo se enfocó en el diseño de un modelo de Franquicia para comercializar calzado en PYMES; aprovechando el impulso que el estado está proveyendo al sector productivo, se proyectó plasmar una idea innovadora y moderna de ventas frente a la inexistencia de un modelo de franquicia para comercializar calzado en nuestro medio....

ANÁLISIS DE INCERTIDUMBRE DE UN MODELO PARA LECHUGAS (Lactuca sativa L. CULTIVADAS EN INVERNADERO

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Irineo Lorenzo López-Cruz

2013-01-01

Full Text Available Un análisis de incertidumbre para un modelo de crecimiento de un cultivo permite evaluar la variabilidad en sus parámetros y deducir una distribución de incertidumbre para cada variable que el modelo predice. Estos estudios se han practicado raramente en modelos para cultivos bajo invernadero. En el presente trabajo se presenta una metodología para llevar a cabo un análisis de incertidumbre para un modelo de un cultivo bajo invernadero y se aplica para determinar la variabilidad de los parámetros del modelo NICOLET desarrollado para explicar el crecimiento de lechugas (Lactuca sativa L.. Se definieron funciones de densidad de probabilidad para todos los parámetros del modelo y se asignaron sus valores mediante muestreo Monte Carlo, aleatorio e hipercubo latino, mediante un total de N = 2000 muestras. Posteriormente se ejecutaron 2000 simulaciones para calcular las salidas del modelo NICOLET para cada escenario. Finalmente, se analizó la distribución de las variables carbono en las vacuolas, carbono en la estructura, peso seco total y contenido de nitratos, mediante el cálculo de sus histogramas y medidas estadísticas. Las simulaciones se realizaron con el programa para análisis de incertidumbre y sensibilidad Simlab, disponible para el ambiente de programación Matlab. La variable carbono en las vacuolas presentó la mayor incertidumbre ya que su coeficiente de variación (CV en ambos muestreos, aleatorio e hipercubo latino, fue de 35.27 y 35.67 %, respectivamente, seguida del contenido de nitratos (CV = 18.16 % y CV = 19.07 %, el carbono estructural (CV = 5.52 % y CV = 5.67 % y el peso seco total (CV = 4.80 % y CV = 4.82 %.

Modelo analítico del efecto de PRS sobre satélites GPS

Science.gov (United States)

Meza, A.; Brunini, C.; Usandivaras, J. C.

El sistema GPS (Global Position System) es, hoy en día, la herramienta de navegación y posicionamiento más potente y lo será sin duda en la próxima década. Gran parte de su valiosa utilidad se debe a la alta precisión que permite lograr y ésta, a su vez, depende, entre otras causas, de la precisión con que se conocen las órbitas de los satélites. La presión de radiación solar (PRS) fija el límite de la precisión con que pueden calcularse en la actualidad las efemérides satelitarias. El objetivo de este trabajo es proponer una mejor resolución de este fenómeno. El modelo analítico aquí presentado, se basa en el análisis del comportamiento de los residuos de un ajuste por mínimos cuadrados en el que se utiliza el modelo de PRS propuesto por Beutler. El mismo consiste en un modelo determinista del fenómeno con dos parámetros libres. Los resultados obtenidos ponen de manifiesto que, aún después de aplicar dichos parámetros, prevalecen en los residuos efectos semidiurnos en las componentes radial,tangencial y normal. Estos resultados obtenidos se comparan con los de un trabajo desarrollado por el Instituto de Berne (Beutler et al., 1994), en el que se utilizaron como pseudo-observaciones las órbitas precisas del IGS (CODE). El intervalo de integración escogido por este centro fueron las semanas 680 y 681. En resumen se tienen arcos de 14 días para todos los satélites, donde las efemérides precisas de los mismos para los 14 días fueron utilizados como pseudo-observaciones. El modelo de fuerza que empleó dicho centro fue básicamente el tradicional en lo que respecta al modelo de las fuerzas gravitacionales, y para la PRS utilizo el modelo standard de Beutler. Los parámetros de este modelo junto con las 6 condiciones iniciales (posición y velocidad) fueron ajustados por el método general de mínimos cuadrados. Los residuos en la componente radial, tangencial y normal, para los satélites con un buen comportamiento, presentan una

MODELO PARA EL PERFECCIONAMIENTO DE LAS COMPETENCIAS DEL INGENIERO INDUSTRIAL BASADO EN LABORATORIOS DE APRENDIZAJE

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Eduyn Ramiro Lopez Santana

2015-09-01

Full Text Available Se propone un modelo basado en la metodología de dinámicas de sistemas que valida las bondades que trae al perfeccionamiento de las competencias del ingeniero industrial de la Universidad Distrital (Colombia basado en los principios de los laboratorios de aprendizaje. Su campo de aplicación permite re-significar el papel que tiene el estudiante y docente en el proceso de aprendizaje. El modelo parte del principio de causalidad que intrínsecamente representa el proceso de aprendizaje y como se puede reforzar el mismo a través de la práctica de la simulación como mecanismo de un laboratorio de aprendizaje. El resultado ha sido la elaboración de varios prototipos de modelo en donde el estudiante se enfrenta a casos de la vida real pero en un ambiente simulado. Los resultados arrojan una serie de propuestas que validan las premisas del modelo de perfeccionamiento, y por otro lado, permitirá en un futuro el desarrollo de modelos de simulación en el contexto de la concepción del laboratorio de aprendizaje.

O MODELO DE PRECIFICAÇÃO POR ARBITRAGEM NO CONTEXTO DOS FUNDOS DE INVESTIMENOS BRASILEIROS

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Bruno Milani

2014-07-01

Full Text Available O objetivo deste estudo é precificar o retorno dos fundos de investimento brasileiros com base na aplicação da Arbitrage Pricing Theory, também conhecido como modelo APT, oriundo dos estudos de Ross (1976. Primeiramente, apresentou-se o modelo original proposto por Ross (1976, além dos fatores definidos posteriormente por Chen, Roll e Ross (1986. Em seguida, foram exploradas as adaptações realizadas para a aplicação do modelo no contexto brasileiro. Utilizando dados de frequência mensal, que abrangem o período de abril de 2001 a fevereiro de 2009, o estudo abordou fundos de investimento de gestão ativa e passiva cujos benchmarks são o Ibovespa e o IBrX, além de segregar todas as análise em quartis, para ajustar-se a possíveis discrepâncias em decorrência das diferenças de tamanho entre os fundos. Os resultados evidenciam que o retorno dos fundos é precificado pelos fatores do modelo APT, tornando este um complemento importante do tradicional modelo CAPM.

Modelo integral de motores alternativos con aplicaciones docentes: motores diesel de inyección directa

OpenAIRE

Torres García, Miguel; Chacartegui, R.; Ruiz Marín, Juan José

2002-01-01

Con fines docentes se ha desarrollado un programa en MATLAB que simula el comportamiento de un MDID utilizando un modelo de combustión de una zona incluyendo renovación de la carga, de fugas y perdidas mecánicas. Para la validación del modelo se han comparado los resultados con los reales de varios motores a pesar de la falta de información detallada del motor. Las mayores diferencias aparecen para régimen de giro alto donde los efectos dinámicos, que este modelo no considera, son...

Modelos matemáticos para o aprimoramento do desempenho térmico de condensadores evaporativos

OpenAIRE

Alex Trigo Nakalski

2007-01-01

Esta dissertação tem por objetivo propor melhorias no desempenho térmico de condensadores evaporativos a partir do estudo de dois modelos desenvolvidos para representar a transferência de calor e a efetividade deste tipo de equipamento, chamados de Ajuste Global e Psicrométrico. São elaborados dois aplicativos computacionais para a simulação dos modelos. Dados experimentais obtidos em uma bancada de testes são usados para o ajuste dos modelos. São apresentados gráficos comparativos do erro re...

Panorama dos modelos de negócios emerg entes da tv digital aberta

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Felippe Souza de Lima

2015-12-01

Full Text Available O presente artigo tem como objetivo descrever modelos de negócios emergentes aplicados àTV digital aberta. A partir de uma pesquisa exploratória, o trabalho apresenta a atual realidadeda televisão aberta e seus modelos de negócios. Posteriormente, é feito um mapeamentopanorâmico buscando, assim, novas oportunidades de geração de receitas em negócio decomunicação audiovisual, considerando novos recursos tecnológicos que foramproporcionados pela digitalização da televisão aberta. Por fim, são apresentados casos,demonstrando maneiras adotadas por emissoras televisivas para gerar conteúdo adicionalmultiplataforma e desdobramentos estratégicos desenvolvidos para captar receitas por meiodestes modelos de negócios emergentes.

Análise de modelos matemáticos aplicados ao estudo de chuvas intensas

Directory of Open Access Journals (Sweden)

C. R. Mello

2001-09-01

Full Text Available A estimativa de chuvas intensas máximas é de grande importância para o dimensionamento de projetos agrícolas, tais como: terraços para controle de erosão, obras de barragens de terra e drenagem em solo agrícola. As chuvas são caracterizadas pela sua intensidade (mm h-1, pelo tempo de duração (min e pelo período de retorno (anos. O modelo básico tem sido usado para determinação da intensidade de precipitação máxima diária a ser aplicada no dimensionamento de estruturas de contenção, fixando-se o período de retorno e a duração da chuva. O tempo de concentração em bacias hidrográficas, que normalmente fica entre 60 e 120 min para bacias consideradas pequenas, tem sido usado como tempo de duração na estimativa de chuvas intensas. Nesse intervalo, existem outros modelos que propiciam melhores ajustes e, conseqüentemente, maior confiabilidade na estimativa da chuva a ser usada nos dimensionamentos de estruturas de contenção. Assim, este trabalho teve como objetivo ajustar dois outros modelos para a estimativa de chuvas intensas: um exponencial e um linear, além do modelo básico. Esses modelos foram ajustados com base em dados de precipitação máxima diária anual da região de Lavras (MG, empregando-se dados de chuvas diárias do período de 1914 a 1991. Os dados foram transformados em intensidades de precipitação, com tempo de retorno variando de 2 a 100 anos e duração entre 5 e 1.440 min. Verificou-se que o modelo exponencial proposto proporcionou melhores ajustes, com menores erros na estimativa, para chuvas variando de 5 a 240 min, sendo, portanto, recomendável a bacias em que o tempo de concentração se enquadre nesta faixa de tempo; o modelo básico mostrou-se mais aplicável a bacias em que o tempo de duração seja maior que 240 min, enquanto o modelo linear não se mostrou confiável para a estimativa de chuvas intensas.

Joint shape segmentation with linear programming

KAUST Repository

Huang, Qixing

2011-01-01

We present an approach to segmenting shapes in a heterogenous shape database. Our approach segments the shapes jointly, utilizing features from multiple shapes to improve the segmentation of each. The approach is entirely unsupervised and is based on an integer quadratic programming formulation of the joint segmentation problem. The program optimizes over possible segmentations of individual shapes as well as over possible correspondences between segments from multiple shapes. The integer quadratic program is solved via a linear programming relaxation, using a block coordinate descent procedure that makes the optimization feasible for large databases. We evaluate the presented approach on the Princeton segmentation benchmark and show that joint shape segmentation significantly outperforms single-shape segmentation techniques. © 2011 ACM.

Modelo de inferencia difuso para estudio de crédito

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SANTIAGO MEDINA HURTADO

2008-01-01

Full Text Available El trabajo presenta el estudio realizado en una cooperativa de servicios financieros, la cual utilizó un Sistema de Inferencia Difuso para evaluar la solvencia de los asociados de la cooperativa solicitantes de crédito. Para desarrollar el modelo se contó con la base de datos de los asociados de la cooperativa y la opinión de expertos. De la base de datos se extrajo información sobre el monto del crédito otorgado, plazo, garantías, aportes sociales e historial crediticio de los clientes, para utilizarlos en el desarrollo del Modelo, el cual parte de definir las relaciones entre las variables de entrada y salida con ayuda del criterio experto. Lo anterior permite definir la base de conocimiento que representa por una parte, el entendimiento que los expertos tienen del fenómeno y por otra, sus sistemas de razonamiento. De esta manera se obtiene un modelo que considera toda la información en el proceso de evaluación crediticia bajo una perspectiva más objetiva con el fin de minimizar así el riesgo operativo y de contraparte en el otorgamiento del crédito.

Segmentation-DrivenTomographic Reconstruction

DEFF Research Database (Denmark)

Kongskov, Rasmus Dalgas

such that the segmentation subsequently can be carried out by use of a simple segmentation method, for instance just a thresholding method. We tested the advantages of going from a two-stage reconstruction method to a one stage segmentation-driven reconstruction method for the phase contrast tomography reconstruction......The tomographic reconstruction problem is concerned with creating a model of the interior of an object from some measured data, typically projections of the object. After reconstructing an object it is often desired to segment it, either automatically or manually. For computed tomography (CT...

Um modelo de hipertexto para apoio ao ensino mediado pela Web

OpenAIRE

Willie Dresler Leiva

2003-01-01

Atualmente há uma demanda crescente por aplicações hipermídia baseadas na WWW (World Wide Web), conhecidas como WIS (Web Information Systems). Esse novo tipo de aplicação apresenta requisitos adicionais aos sistemas de software clássicos, o que resulta na necessidade de investigar modelos mais adequados para apoiar o seu desenvolvimento. Em especial, os sistemas para apoio ao EaD (Ensino a Distância) baseados na Web apresentam características e requisitos ainda mais específicos. Os modelos at...

Modelo Predictivo para la Permanencia en la Educación Superior

OpenAIRE

Rodríguez, Vera Montserrat; González Campos, José; Patricio Aguilera, Juan

2017-01-01

El objetivo de este trabajo es reportar el modelo multivariado predictivo para la permanencia universitaria a partir de atributos previos al ingreso a la universidad y de variables medidas durante el primer semestre de 2017 de los estudiantes de la Universidad de Playa Ancha que ingresaron a la universidad a través del Programa de Acompañamiento y Acceso Efectivo a la Educación Superior del Ministerio de Educación de Chile.El presente texto describe de manera breve el modelo de Tinto (1975). ...

Clasificación de los modelos de comercio electrónico

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Celestino Robles Estrada

2016-02-01

Full Text Available El presente artículo describe y analiza tres de las principales aportaciones realizadas hasta el presente para clasificar los modelos de negocio, mismos que se han desarrollado gracias a internet. En específico, describe y analiza las taxonomías propuestas por Tapscott, Timmers y Rappa, y hace una reflexión final sobre la complejidad de diseñar un modelo taxonómico único que explique adecuadamente los diferentes tipos de comercio electrónico  que se han desarrollado hasta la fecha.

Rediscovering market segmentation.

Science.gov (United States)

Yankelovich, Daniel; Meer, David

2006-02-01

In 1964, Daniel Yankelovich introduced in the pages of HBR the concept of nondemographic segmentation, by which he meant the classification of consumers according to criteria other than age, residence, income, and such. The predictive power of marketing studies based on demographics was no longer strong enough to serve as a basis for marketing strategy, he argued. Buying patterns had become far better guides to consumers' future purchases. In addition, properly constructed nondemographic segmentations could help companies determine which products to develop, which distribution channels to sell them in, how much to charge for them, and how to advertise them. But more than 40 years later, nondemographic segmentation has become just as unenlightening as demographic segmentation had been. Today, the technique is used almost exclusively to fulfill the needs of advertising, which it serves mainly by populating commercials with characters that viewers can identify with. It is true that psychographic types like "High-Tech Harry" and "Joe Six-Pack" may capture some truth about real people's lifestyles, attitudes, self-image, and aspirations. But they are no better than demographics at predicting purchase behavior. Thus they give corporate decision makers very little idea of how to keep customers or capture new ones. Now, Daniel Yankelovich returns to these pages, with consultant David Meer, to argue the case for a broad view of nondemographic segmentation. They describe the elements of a smart segmentation strategy, explaining how segmentations meant to strengthen brand identity differ from those capable of telling a company which markets it should enter and what goods to make. And they introduce their "gravity of decision spectrum", a tool that focuses on the form of consumer behavior that should be of the greatest interest to marketers--the importance that consumers place on a product or product category.

ANÁLISIS DE UN MODELO DE RED DE RELACIONES EN ÁREAS INNOVADORAS

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Beatriz González Vázquez

2006-01-01

Full Text Available La estructura de relaciones sobre la que se asientan las áreas económicas ha adquirido gran importancia en los últimos años; y si además esto se traslada a un entorno innovador, donde la transferencia de conocimiento se realiza a través de dichas relaciones, éstas devienen en fundamentales. El objetivo de este artículo es comprobar si existe un modelo en la red de relaciones que se establece en un área de alta tecnología. Para alcanzar el objetivo anterior, hay que estudiar la red que se conforma en dichos espacios tanto desde una perspectiva reticular, como de la búsqueda de un modelo explicativo. En el modelo se incorpora, además de los atributos de las empresas, las variables relacionales extraídas de los flujos interorganizativos. Se aplica el modelo a las redes de tres Parques Tecnológicos, y en los resultados se observa que la estructura de la red viene determinada, además de las variables consideradas, por la condiciones socioinstitucionales e industriales del área geográfica sobre la que se asientan.

Modelo de negocio para emprendedores: Estudio de caso

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Ruben Macías Acosta

2015-11-01

Full Text Available Las empresas y los emprendedores necesitan estructurar proyectos que sean viables, por lo cual la generación de valor debe estar presente en los mismos. El modelo de negocios canvas es una herramienta que permite desarrollar estrategias adecuadas para las empresas o emprendedores que generen valor. El objetivo del artículo es dar a conocer el modelo de negocios canvas y presentar un caso de éxito del proyecto Taxiwoman mediante el uso de esta metodología. La metodología realizada en la investigación fue cualitativa, ya que solo se realizó el llenado del lienzo, no probabilísticos, y el tamaño de la muestra fue del grupo de trabajo, la unidad de análisis fue el resultado del proyecto de los estudiantes. Los resultados de la factibilidad del proyecto fueron obtenidos mediante la evaluación emitida por los jurados del Evento Nacional de Innovación Tecnológica 2014. Por lo que se concluye que el modelo de negocios canvas es una herramienta efectiva en la estructuración de los modelos de negocio, ya que considera todos los aspectos clave necesarios de un negocio. Companies and entrepreneurs need to structure projects that are viable, so generating value must be included. Companies or entrepreneurs can create value by designing their business models by using the Canvas methodology. The aim of this article is to explain the development of a business model using the Canvas methodology to design the project, presenting the success story of Taxiwoman project. The Taxiwoman project was part of several competitions of entrepreneurs in Mexico, its presentation at the National Technological Innovation Event 2014 (ENIT 2014 was outstanding; in the first phase of the event different projects from the State of Aguascalientes, in the second phase there were different projects from several States of the region. Due to the success of the competitions, it was possible to corroborate the feasibility of using the Canvas methodology for designing business

Un modelo para la optimización de políticas de inventario conjuntas en cadenas de suministro

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Ernesto Pacheco Velásquez

2013-01-01

Full Text Available La evolución en la manera de operar de las cadenas de suministro obliga a replantear los modelos utilizados para optimizarla. Si bien es cierto que los modelos tradicionales de inventarios proveen de una guía en la formulación de los nuevos modelos, es necesario entender cuáles de los supuestos deben mantenerse y cuáles deberían cambiarse. En este artículo se contempla la creación de un modelo que minimiza los costos de inventarios en un eslabón cliente-proveedor dentro la cadena de suministro. Se ha utilizado el cálculo diferencial para alcanzar la optimización de este modelo. Los resultados se comparan con los obtenidos por otros autores que han mantenido la perspectiva clásica y se basan en la formulación original de los modelos de la cantidad económica de pedido y el tamaño económico del lote de producción.

O ensino de biblioteconomia no Brasil: questões acerca do modelo deweyano

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Francisco das Chagas de Souza

1997-04-01

Full Text Available Parte da idéia de que há um modelo Deweyano de Organização da Informação e que a este liga-se um modelo de Educação bibliotecária. Ambos, enquanto prática e formação de recursos humanos, são enformados por um paradigma geral, o Paradigma da Estabilidade da Organização da Informação.

Reflection symmetry-integrated image segmentation.

Science.gov (United States)

Sun, Yu; Bhanu, Bir

2012-09-01

This paper presents a new symmetry-integrated region-based image segmentation method. The method is developed to obtain improved image segmentation by exploiting image symmetry. It is realized by constructing a symmetry token that can be flexibly embedded into segmentation cues. Interesting points are initially extracted from an image by the SIFT operator and they are further refined for detecting the global bilateral symmetry. A symmetry affinity matrix is then computed using the symmetry axis and it is used explicitly as a constraint in a region growing algorithm in order to refine the symmetry of the segmented regions. A multi-objective genetic search finds the segmentation result with the highest performance for both segmentation and symmetry, which is close to the global optimum. The method has been investigated experimentally in challenging natural images and images containing man-made objects. It is shown that the proposed method outperforms current segmentation methods both with and without exploiting symmetry. A thorough experimental analysis indicates that symmetry plays an important role as a segmentation cue, in conjunction with other attributes like color and texture.

Medidas da condutividade térmica efetiva de modelos de polpas de frutas no estado congelado

Directory of Open Access Journals (Sweden)

Resende Jaime Vilela de

2002-01-01

Full Text Available As propriedades termofísicas de alimentos, necessárias nas simulações e cálculos do processo de congelamento, incluem principalmente a densidade, condutividade térmica e calor específico. Neste trabalho, as difusividades e condutividades térmicas da solução, usadas como modelo para o congelamento de polpas de frutas, foram medidas pelo método da sonda com aquecimento. Os experimentos foram conduzidos na faixa de -25 a 0masculineC com modelos alimentícios constituídos de 0,5% de K- carrageenan + 10% de sacarose (massa/volume de água. Modelos estruturais foram usados para as avaliações da condução de calor, combinada com a fração de gelo predita para as amostras a partir dos modelos de Heldman e foram comparados com os valores das condutividades térmicas efetivas medidas. Os modelos estruturais empregados foram: em série, paralelo e Maxwell-Eucken, com o gelo considerado como a fase dispersa. Em todos os ensaios, o modelo de Maxwell-Eucken apresentou os melhores resultados (erro máximo de 6,13% quando comparado com os valores experimentais medidos e foi escolhido para a predição da condutividade térmica efetiva de soluções-modelo de polpas de frutas congeladas. Os valores calculados da condutividade térmica foram ajustados em termos de funções polinomiais, divididas em quatro faixas de temperatura e podem ser usadas na resolução dos problemas de transferência de calor, nos processos de congelamento.

Un modelo de gestión ambiental para empresas fabricantes de pinturas

Directory of Open Access Journals (Sweden)

Humberto Palos Delgadillo

2016-02-01

Full Text Available Dada una problemática medioambiental que existe en las organizaciones, y particularmente la que se manifiesta en la empresa mexicana, la presente investigación está referida a una empresa dedicada a la fabricación de pinturas y recubrimientos, instalada en la ciudad de Guadalajara. En este sentido, el propósito de esta investigación  es presentar un modelo de gestión ambiental en una empresa seleccionada. El modelo desarrollado está basado en el ciclo de mejora continua de Edward Deming que incluye las cuatro etapas: planear, hacer, verificar y actuar, y donde se dan a conocer las relaciones que fundamentan el modelo con las estrategias propuestas; además, se discuten los indicadores ambientales, los procedimientos, la identificación de las áreas  generadoras de desechos, y finalmente la implantación del sistema.

Comparación de modelos de calidad, factores y métricas

Directory of Open Access Journals (Sweden)

Marcela Alejandra Constanzo

2014-07-01

Full Text Available Existen diferentes enfoques de desarrollo de software, en su mayoría priorizan lacalidad en el proceso y el producto obtenido. Para poder lograr esto es importante el uso de modelos de calidad apropiados para cada metodología. Estos modelos de calidad presentan factores e indicadores que describen las características del software y sus relaciones y pueden ser adaptaciones de otros o creados tomando como base los estándares existentes.Este trabajo describe y analiza algunos modelos de calidad desarrollados para las metodologías de desarrollo de software orientada a objetos, a componentes, a aspectos y los métodos ágiles, realiza una comparación según los criterios, factores y características que lo componen, niveles de abstracción y métricas para llevar a cabo la medición.

MODELO PARA LA CREACIÓN DEL CONOCIMIENTO PARA PYMES

Directory of Open Access Journals (Sweden)

Marino Valencia Rodríguez

2009-01-01

Full Text Available La creciente importancia del conocimiento, como nuevo factor de producción, hace que la creación y transferencia se convierta en una de las principales prioridades de las organizaciones. El presente artículo describe tanto los fundamentos de la teoría de los recursos y capacidades de la empresa como el enfoque de la gestión del conocimiento, con sus procesos de generación y transferencia del conocimiento. Estos sirven de guía básica teórica para alcanzar el siguiente objetivo: Diseñar un modelo de generación y transferencia de conocimiento para los procesos de dirección, gestión humana y del conocimiento para PyMES, con el fin de que éstas alcancen mayores niveles de competitividad. El modelo se diseña, a partir del direccionamiento estratégico de la organización. Está conformado por tres etapas, articuladas con elementos y actividades. Las acciones se enfocan en dos factores clave de éxito: la cultura organizacional y la formación. La utilización del modelo permitirá a las PyMES optimizar los recursos y capacidades disponibles, lo cual se refleja en el desempeño del trabajador y en el fortalecimiento de la cultura organizacional.

Modelo formal de pruebas funcionales de software para alcanzar el Nivel de Madurez Integrado 2

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Milton Eduardo Escobar-Sánchez

2015-05-01

Full Text Available Las aplicaciones de software son cada vez más importantes para las organizaciones debido a que permiten llevar a cabo efiientemente sus tareas primordiales; por ello es mandatorio realizar las pruebas de calidad de software. Esta investigación se enfocó en diseñar un modelo formal para desarrollar pruebas funcionales de software que permitan alcanzar el nivel de calidad 2 del Modelo de Madurez de Pruebas Integrado (TMMI. El proceso se inició con un diagnóstico situacional, aplicando la norma ISO-9001-2000; luego, se evaluaron diversos modelos de prueba de calidad de software, como el ISO/IEC 9126, el TMM, el TMMI, el Proceso de Mejoramiento de Pruebas (TPI y el Enfoque de Gestión de Pruebas (TMAP, realizando una comparación bajo algunos criterios como año de publicación, licenciamiento, niveles, factorías y riesgos. Con esta información se diseñó el modelo propuesto, que es independiente del proceso de desarrollo de software. Concretamente, se fundamentó en el ciclo de prueba, y se compone de cuatro fases: Especifiación, Planifiación, Ejecución y Evaluación, en el que se contrasta en forma real el comportamiento esperado del software. Como caso de estudio y validación se aplicó este modelo a una PYME; los resultados mostraron la efiiencia del modelo y revelaron que es preciso desarrollar una cultura de calidad organizacional en esta empresa.

Lung segment geometry study: simulation of largest possible tumours that fit into bronchopulmonary segments.

Science.gov (United States)

Welter, S; Stöcker, C; Dicken, V; Kühl, H; Krass, S; Stamatis, G

2012-03-01

Segmental resection in stage I non-small cell lung cancer (NSCLC) has been well described and is considered to have similar survival rates as lobectomy but with increased rates of local tumour recurrence due to inadequate parenchymal margins. In consequence, today segmentectomy is only performed when the tumour is smaller than 2 cm. Three-dimensional reconstructions from 11 thin-slice CT scans of bronchopulmonary segments were generated, and virtual spherical tumours were placed over the segments, respecting all segmental borders. As a next step, virtual parenchymal safety margins of 2 cm and 3 cm were subtracted and the size of the remaining tumour calculated. The maximum tumour diameters with a 30-mm parenchymal safety margin ranged from 26.1 mm in right-sided segments 7 + 8 to 59.8 mm in the left apical segments 1-3. Using a three-dimensional reconstruction of lung CT scans, we demonstrated that segmentectomy or resection of segmental groups should be feasible with adequate margins, even for larger tumours in selected cases. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

New experimental model for training in videosurgery Novo modelo experimental para treinamento em videocirurgia

Directory of Open Access Journals (Sweden)

Danilo Malta Batista

2012-10-01

Full Text Available PURPOSE: To develop a new experimental model of lower cost for training in videosurgery. METHODS: This project was performed at the Nucleus of Experimental Surgery of the Bahiana School of Medicine and Public Health, based on previous models described in the literature and under the supervision of the full professor of Operative Technique and Experimental Surgery II. It was made a model cube-shaped, made of wood, with holes distributed in various locations, rubber stoppers for the holes and lined externally with carpet, and internally with laminate. RESULTS: The new experimental model is of low cost and reproduces quite faithfully several videosurgical procedures. CONCLUSION: Medical schools interested in the subject may adopt the new model for training in videosurgery without the need of high costs for making and using these models.OBJETIVO: Desenvolver um novo modelo experimental de baixo custo para treinamento em videocirurgia MÉTODOS: Este projeto foi conduzido no Núcleo de Cirurgia Experimental da Escola Bahiana de Medicina e Saúde Pública, baseado em modelos prévios descritos na literatura e sob a supervisão do professor titular de Técnica Operatória e Cirurgia Experimental II. Foi feito um modelo em formato de cubo, de madeira, com furos distribuídos em vários locais, tampas de borracha para os orifícios e forrado externamente com carpete e internamente com laminado. RESULTADOS: O novo modelo experimental desenvolvido é de baixo custo e reproduz de forma bastante fiel diversos procedimentos videocirúrgicos. CONCLUSÃO: Faculdades médicas interessadas no tema poderão adotar o novo modelo para o treinamento em videocirurgia sem que sejam necessários gastos elevados para a confecção e o uso desses modelos.

Taxonomía de los modelos y metodologías de desarrollo de software más utilizados

OpenAIRE

J. Cervantes Ojeda; María del Carmen Gómez Fuentes

2012-01-01

A través de una recopilación y análisis de los principales modelos de desarrollo de software existentes, proponemos una taxonomía que los integra con el fin de facilitar la e lección de un modelo apropiado para cada proyecto en particular. Una buena elección de modelo (correctamente aplicado) ahorra tiempo y mejora la calidad de los sistemas que se producen. Sin embargo, la amplia variedad de modelos y metodologías en el mundo del desarrollo de software, dificulta esta elección. La taxonomía ...

El desarrollo de software dirigido por modelos en los repositorios institucionales

Directory of Open Access Journals (Sweden)

Jose Texier

2014-01-01

Full Text Available Los Repositorios Institucionales (RI se han consolidado en la academia, prueba de ello es el crecimiento en número de registros en los directorios existentes realizado por diferentes vías: autoarchivo por parte de autores, la incorporación de material a cargo de bibliotecarios, entre otras. En este trabajo se hace un relevamiento bibliográfico sobre el uso del enfoque de Desarrollo de Software Dirigido por Modelos (MDD en los sistemas de RI con el propósito de establecer una relación entre ellos. El MDD es un paradigma de construcción de software que asigna a los modelos un rol central y se derivan modelos que van desde los más abstractos a los más concretos. Este paradigma, además, proporciona un marco de trabajo que permite a los interesados compartir sus puntos de vista y manipular las representaciones de las entidades del dominio. En conclusión, el seguimiento de las diferentes investigaciones relevadas y lo aquí expuesto permiten incentivar implementaciones de software para los RI.

Modelos de servicios bibliotecarios: el acceso a la información

Directory of Open Access Journals (Sweden)

El acceso a los servicios bibliotecarios se ha visto modificado y adaptado con el paso del tiempo. El modelo cerrado, instaurado por la realeza, nobleza y los dueños de las bibliotecas, que perduró hasta el siglo XV se transformó en un modelo abierto al permitir la entrada a los ciudadanos a los fondos. Hasta finales del siglo XX, los usuarios acudían a los centros para consultar fondos y satisfacer sus necesidades documentales. Desde finales del siglo XX es posible acceder a la información a través de Internet y gracias a las asociaciones y consorcios de las bibliotecas la oferta documental ha incrementado, teniendo en cuenta connotaciones como la propiedad física de los documentos frente a la propiedad virtual de los mismos. El sistema bibliotecario en combinación con las tecnologías de la información y la comunicación ha modificado el modelo de servicios existente hasta la fecha.

2008-12-01

Full Text Available El acceso a los servicios bibliotecarios se ha visto modificado y adaptado con el paso del tiempo. El modelo cerrado, instaurado por la realeza, nobleza y los dueños de las bibliotecas, que perduró hasta el siglo XV se transformó en un modelo abierto al permitir la entrada a los ciudadanos a los fondos. Hasta finales del siglo XX, los usuarios acudían a los centros para consultar fondos y satisfacer sus necesidades documentales. Desde finales del siglo XX es posible acceder a la información a través de Internet y gracias a las asociaciones y consorcios de las bibliotecas la oferta documental ha incrementado, teniendo en cuenta connotaciones como la propiedad física de los documentos frente a la propiedad virtual de los mismos. El sistema bibliotecario en combinación con las tecnologías de la información y la comunicación ha modificado el modelo de servicios existente hasta la fecha.

Las emociones en el deporte: Conceptos empleados en un modelo tridimensional

Directory of Open Access Journals (Sweden)

Alexander T. Latinjak

2014-01-01

Full Text Available La psicología del deporte utiliza modelos dimensionales para organizar el complejo mundo de las emociones. Este trabajo estudia los conceptos empleados en el modelo de Latinjak (2012, que incorpora la perspectiva temporal a las dimensiones tradicionales de valor y activación en el ámbito deportivo. El objetivo principal del presente estudio fue determinar los conceptos más pertinentes para las ocho emociones principales del modelo. Para ello se realizó una investigación en tres etapas consistentes en (a encontrar conceptos diferentes para las ocho emociones, (b escoger el más adecuado en cada caso, y (c comprobar su especificidad. Para cada etapa se empleó una muestra diferente y medidas ajustadas a los objetivos. Los resultados permiten indicar los conceptos que mejor definen las ocho emociones principales señaladas en Latinjak (2012, y aportar evidencias en favor de la perspectiva temporal. Finalmente, se discuten algunas aportaciones teóricas y prácticas y las limitaciones del estudio.

Aplicaciones del modelo On/Off al tráfico agregado en las redes de comunicaciones

OpenAIRE

Parra León, Andrés; Piedrahita, Elkin M; Salcedo, Octavio

2011-01-01

Los modelos que permiten recrear trazas de tráfico generadas en una red de comunicaciones, pueden utilizarse en predicciones y estimaciones de tráfico a fin de optimizar el uso de los recursos de la red; uno de estos es el modelo On/Off, el cual permite describir el comportamiento del tráfico agregado por una o más fuentes de información. La importancia de este artículo se centra en la incidencia que dicho modelo ha tenido al aplicarse en diversas tecnologías de comunicaciones, para esto se e...

Equações discretas no ensino médio: modelos de dinâmicas populacionais

OpenAIRE

Maligeri, Glaucía Cristina Alecci Meneghim [UNESP

2013-01-01

As equações discretas fornecem as ferramentas matemáticas básicas para a correta modelagem da dinâmica populacional ao se tomar como hipótese tempos discretos. Neste trabalho, apresentamos a teoria das equações discretas e algumas aplicações no capítulo 01, dando ênfase aos modelos de dinâmica populacional conhecidos como modelo de Malthus e de Verhulst junto com exemplos que evidenciam tais modelos na modelagem de populações reais. No capítulo 02 apresentamos duas propostas didáticas; a prim...

Sipunculans and segmentation

DEFF Research Database (Denmark)

Wanninger, Andreas; Kristof, Alen; Brinkmann, Nora

2009-01-01

mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral...

Modelos de Previsión del Fracaso Empresarial: ¿Funciona Entre Nuestras Empresas el Modelo de Altman de 1968?

Directory of Open Access Journals (Sweden)

Fermín Lizarraga Dallo

1998-06-01

Full Text Available El modelo discriminante de Altman (1968 ha sido muchas veces propuesto como herramienta válida de predicción en los dos años previos al fracaso de la empresa. Esta supuesta utilidad exige ser contrastada previa aplicación a condiciones geográficas y de información contable distintas a las utilizadas para su estimación. El trabajo que aquí se presenta contrasta el comportamiento del modelo utilizando una muestra de 120 empresas industriales españolas de tamaño medio, tomando como definición de fracaso la solicitud de un procedimiento concursal de suspensión de pagos. Las conclusiones obtenidas tras diferentes fases de reestimación sugieren la no conveniencia de una aplicación directa del modelo, cuyo comportamiento mejora sustancialmente al reducir sus cinco variables a únicamente dos, representativas de la rentabilidad de activos una vez incorporado el efecto de la carga financiera sobre la cifra de resultado y del nivel de endeudamiento calculado a valores contables. Altman's 1968 discriminant model has been presented as a useful prediction tool for the two years previous to firm failure. However, this utility must be tested before its aplication to geografical and accounting information conditions different from the original ones. The main purpose of this study is to analyze the behaviour of the model in a sample of 120 medium-sized industrial Spanish firms, using "suspensión de pagos" as a definition of failure. After a reestimation process we conclude about the non-convenience of a direct aplication of the model, finding a substantial improvement after reducing the number of variables from five to two, representative of asset profitability (once incorporated the effect of interest charges on net income and financial leverage.

Modelo integral para la evaluación de la calidad de la accesibilidad al contenido web

OpenAIRE

Gallardo, Cecilia Elizabeth; Funes, Ana; Ahumada, Hernán César

2016-01-01

El presente trabajo, que se enmarca en el área del Aseguramiento de la Calidad del Software, busca dar respuesta a la necesidad de contar con un modelo integral o marco de referencia que permita conceptualizar y, posteriormente, evaluar la accesibilidad al contenido web. Para tal fin, se propone, por un lado, el desarrollo de un modelo de conceptos de calidad correspondiente a la subcaracterística Accesibilidad del modelo de calidad de la norma ISO 25010, para lo cual se analizarán las Pau...

Modelo base para la gestión del conocimiento de empresas peruanas que realicen actividades operativas

OpenAIRE

Vilca Taco, Yaneth

2013-01-01

El propósito de la presente investigación es plantear un modelo de gestión de conocimiento para empresas peruanas medianas y pequeñas que realicen actividades operativas en el sector minero. Por ello se estudia diversos modelos de gestión, para luego aplicar el modelo IC-PHVA en la investigación. Al finalizar este estudio se concluye que gestionar los conocimientos implica caracterizar los recursos intangibles de una organización, con lo cual podremos identificar, cuantificar e inventariar el...

Using Predictability for Lexical Segmentation.

Science.gov (United States)

Çöltekin, Çağrı

2017-09-01

This study investigates a strategy based on predictability of consecutive sub-lexical units in learning to segment a continuous speech stream into lexical units using computational modeling and simulations. Lexical segmentation is one of the early challenges during language acquisition, and it has been studied extensively through psycholinguistic experiments as well as computational methods. However, despite strong empirical evidence, the explicit use of predictability of basic sub-lexical units in models of segmentation is underexplored. This paper presents an incremental computational model of lexical segmentation for exploring the usefulness of predictability for lexical segmentation. We show that the predictability cue is a strong cue for segmentation. Contrary to earlier reports in the literature, the strategy yields state-of-the-art segmentation performance with an incremental computational model that uses only this particular cue in a cognitively plausible setting. The paper also reports an in-depth analysis of the model, investigating the conditions affecting the usefulness of the strategy. Copyright © 2016 Cognitive Science Society, Inc.

Efficient graph-cut tattoo segmentation

Science.gov (United States)

Kim, Joonsoo; Parra, Albert; Li, He; Delp, Edward J.

2015-03-01

Law enforcement is interested in exploiting tattoos as an information source to identify, track and prevent gang-related crimes. Many tattoo image retrieval systems have been described. In a retrieval system tattoo segmentation is an important step for retrieval accuracy since segmentation removes background information in a tattoo image. Existing segmentation methods do not extract the tattoo very well when the background includes textures and color similar to skin tones. In this paper we describe a tattoo segmentation approach by determining skin pixels in regions near the tattoo. In these regions graph-cut segmentation using a skin color model and a visual saliency map is used to find skin pixels. After segmentation we determine which set of skin pixels are connected with each other that form a closed contour including a tattoo. The regions surrounded by the closed contours are considered tattoo regions. Our method segments tattoos well when the background includes textures and color similar to skin.

Modelo de negocios de una red social orientada a la comunidad LGBTI

OpenAIRE

Ochoa Franco, César Eduardo; Arroyave Roldán, Fabio Alejandro

2015-01-01

En el presente trabajo de grado del MBA de la Universidad EAFIT, se plantea la generación de un modelo de negocios de redes sociales, orientado en la comunidad de lesbianas, gays, bisexuales, transexuales, transgénero e intersexuales (en adelante LGBTI), basado en el modelo Canvas -- Para este fin se toman fuentes secundarias y primarias; estas últimas son tomadas mediante las metodologías de investigación: entrevista semiestructurada, grupo focal y encuesta, por medio de las cuales se determ...

Percepción por un modelo de fachada vegetada

Directory of Open Access Journals (Sweden)

Jazmin Carbajal-Avila

2016-07-01

Full Text Available El presente estudio tuvo por objetivo mostrar la percepción sobre un sistema de fachada vegetada ubicada en Acapulco, México; para lo cual se aplicó un sondeo a estudiantes de nivel superior. Los resultados muestran las sensaciones y los beneficios que fueron percibidos por el modelo, así como los inmuebles más convenientes para su aplicación, su apreciación económica y los colores preferentes en las flores de la vegetación. Las conclusiones indicaron que en un clima cálido-húmedo el modelo tiene una sensación visual refrescante de la temperatura ambiente. También se encontró su efecto reparador en ambientes estresantes. CC BY-NC-SA Gestión y Ambiente (2016.

ESTUDIO DEL MODELO DE PROPAGACIÓN SUZUKI PARA REDES MÓVILES

Directory of Open Access Journals (Sweden)

Gina Sierra

2013-12-01

Full Text Available Este artículo presenta brevemente la teoría fundamental del Modelo Suzuki comúnmente usado para modelar la propagación en canales inalámbricos. El modelo toma en cuenta los efectos del sombreado y del multi-trayecto de manera simultánea. Además, se valida el modelo mediante una comparación estadística entre mediciones realizadas en el entorno real y simulaciones realizadas en MATLAB® a través de la generación de series de tiempo Suzuki distribuidas. Las mediciones se realizaron durante diez horas sobre la banda de frecuencias entre 850 MHz y 900 MHz. Con los datos obtenidos en medición durante los primeros cinco minutos, se caracterizó el canal inalámbrico para cada una de las frecuencias muestreadas calculando la media y desviación estándar de la señal recibida. Estos dos parámetros fueron introducidos como variables de entrada para la generación de las respectivas series de tiempo. Para cada frecuencia se realizaron simulaciones prediciendo los niveles de la señal que se obtendrían durante diez horas. Finalmente, se calculó el error cuadrático medio entre los valores medidos y los valores generados en simulación. Los resultados obtenidos demuestran que el modelo es válido como una herramienta de predicción de las características de propagación en comunicaciones móviles.

MODELO MATEMÁTICO APLICADO A LA CURVA DE LACTANCIA EN GANADO VACUNO DOBLE PROPÓSITO

Directory of Open Access Journals (Sweden)

Luz Botero

2006-05-01

Full Text Available hembras vacunas. Materiales y métodos. Durante 11 meses, se estudió la producción de leche en 500novillas doble propósito Bos taurus x Bos indicus, de las sabanas del trópico bajo colombiano. Laproducción se cuantificó en kilogramos. Se incluyeron los datos de la producción de leche en época(seca-lluviosa y número de lactancias (primera; segunda y tercera y, más de tres. Los datos hacen partedel archivo de la Ganadería XB, ubicada en las sabanas de Bolívar, Colombia, recopilados desde el año1990 hasta el 2000. A estos datos se le aplicó los modelos lineal simple, cuadrático, lineal logarítmico,cuadrático logarítmico, gamma incompleto, lineal hiperbólico y polinomial inverso. Los parámetros paralos modelos gamma incompleto y polinomial inverso fueron estimados, a partir del método de “Gauss-Newton”, para la regresión no lineal; los demás modelos fueron ajustados por regresión lineal de lasproducciones, en función de los meses en lactancia, por el método de los cuadrados mínimos. Resultados.En los modelos propuestos, se observó que el modelo polinomial inverso es el que mejor caracteriza lacurva de lactancia por presentar los mayores valores para el estadístico Durbin-Watson y coeficiente dedeterminación (R2 y sobre dicho modelo existe información necesaria para obtener parámetros prácticoscalculados a partir de la ecuación de la curva de lactancia. Conclusión. El modelo matemático polinomialinverso se constituye en una excelente herramienta para aplicar en la administración y toma de decisionesen el manejo de hatos del sistema de doble propósito

Hacia la construcción de un Modelo Integral de Organizaciones Saludables

Directory of Open Access Journals (Sweden)

Merlin Patricia Grueso-Hinestroza

2013-01-01

Full Text Available El concepto de organización saludable adquiere cada vez mayor relevancia en el mundo académico y empresarial, pues se ha defendido que estas se encuentran relacionadas con resultados positivos en función de los distintos grupos de interés: empleados, socios, proveedores, clientes y la sociedad. Con fundamento de lo anterior, se plantea como objetivo de este artículo, proponer un modelo explicativo de organización saludable. Para lograr dicho propósito, se emplea una metodología descriptiva, en tanto se compilan diferentes aproximaciones y modelos existentes que enfocan distintos aspectos de la salud-enfermedad en las instituciones. Como resultado del análisis, se propone un modelo explicativo de organización saludable que busca ser integrador e incorpora factores internos y externos que determinan el bienestar de la organización y el de sus grupos de interés.

Adequabilidade dos principais modelos de periodização do treinamento esportivo

Directory of Open Access Journals (Sweden)

Estélio Henrique Martin Dantas

2011-06-01

Full Text Available O estudo identificou, sob o prisma da adequabilidade, qual o melhor modelo de periodização do treinamento esportivo (PTE. Foram considerados dois indicadores: a estrutura da periodização e a forma de modulação da carga. Foi utilizada a metanálise como ferramenta metodológica. 103 citações foram levantadas numa pesquisa sistemática, em bases de dados. A avaliação pelos critérios estabelecidos indicou cinco modelos de PTE passíveis de estudo. A análise estatística, empregando o tamanho efeito (TE, gerou um Índice de Adequabilidade (IADEQ e a classificação dos modelos em: Muito Bom - Matveev (IADEQ = 3,44; TE = 1,13; Bom - Verkhoshansky (IADEQ = 2,88; TE = 0,57, Bompa (IADEQ = 2,66; TE = 0,34 e Regular - ATR (IADEQ = 1,96; TE = -0,37, Forteza (IADEQ = 2,25; TE = -0,07.

Transformações no modelo industrial, "novos" trabalhos e nova temporalidade

OpenAIRE

Aquino,Cássio Adriano Braz de

2007-01-01

O presente artigo visa à análise da transformação da temporalidade, como elemento chave para a compreensão das mudanças no mundo do trabalho. Tomamos como referente dessa análise as teorias dos tempos sociais e a idéia do tempo dominante na constituição dos quadros temporais das sociedades. A passagem de um modelo de temporalidade relativamente estável e quase hegemônica do modelo industrial, para um tempo cada vez mais diversificado e diluído, advindo das novas jornadas - com durações e ritm...

Un modelo Macroeconométrico para la Economía Colombiana.

Directory of Open Access Journals (Sweden)

Javier Arturo Birchenall

2010-05-01

Full Text Available Este documento analiza un modelo macroeconométrico de corto plazo para la economía colombiana, con el fin de evaluar el impacto de procesos de ajuste y estabilización. Se basa en una estructura que reconoce no neutralidades por rigideces de precios y descompone la economía a través de oferta y demanda agregada. El modelo se estima por diversos métodos para el período comprendido entre 1977 y 1998 con una frecuencia trimestral, con el fin de realizar proyecciones para períodos de uno y dos años.

Modelos de acceso abierto en educación y ciencia

Directory of Open Access Journals (Sweden)

Karen Isabel Cabrera-Peña

2014-08-01

Full Text Available Este artículo presenta los modelos de acceso abierto en educación y ciencia, implementados en seis países pioneros en el tema (Argentina, Australia, Brasil, Estados Unidos, Inglaterra y España, desde la perspectiva de la Unión Europea. El análisis parte del marco político y legal de acceso abierto, hasta la interrelación de los modelos implementados en cada uno de los países de estudio. Se concluye que lo "abierto" contribuye a la calidad de los procesos de información y conocimiento; sin embargo, existen dificultades tecnológicas y legales para su implementación.

Fold distributions at clover, crystal and segment levels for segmented clover detectors

International Nuclear Information System (INIS)

Kshetri, R; Bhattacharya, P

2014-01-01

Fold distributions at clover, crystal and segment levels have been extracted for an array of segmented clover detectors for various gamma energies. A simple analysis of the results based on a model independant approach has been presented. For the first time, the clover fold distribution of an array and associated array addback factor have been extracted. We have calculated the percentages of the number of crystals and segments that fire for a full energy peak event

Aproximación de un modelo didáctico para la creación de objetos virtuales de aprendizaje

OpenAIRE

Arango Vásquez, Sandra Isabel; Universidad de Medellín; Vásquez Lopera, Claudia Patricia; Universidad de Medellín; Salazar Ceballos, Alexander; Universidad del Magdalena; Álvarez-Miño, Lídice; Universidad del Magdalena

2013-01-01

Este artículo muestra los hallazgos iniciales del proyecto “Modelo didáctico para la creación de objetos virtuales de aprendizaje soportado en una red académica de alta velocidad”. La Universidad de Medellín y la Universidad del Magdalena presentan una aproximación a este modelo teniendo en cuenta la conceptualización de los enfoques pedagógicos, los modelos pedagógicos y los modelos didácticos. Esta investigación de corte cualitativo con enfoque hermenéutico obtuvo como resultados iniciales ...

Constructos y variables del ambiente virtual de aprendizaje, desde la perspectiva del modelo de ecuaciones estructurales

Directory of Open Access Journals (Sweden)

Alfredo Ángel Ramírez\\u2013Carbajal

2016-01-01

Full Text Available Este artículo presenta el diseño y los resultados de un proyecto de investigación. Se inicia con la contextualización en el área educativa y enseguida se describe una aproximación a la revisión de la literatura sobre el ambiente virtual de aprendizaje y el modelo de ecuaciones estructurales. En la fundamentación, se explican las teorías de la acción razonada, la del modelo de aceptación de la tecnología, la del modelo de éxito de los sistemas de información y la del modelo de ecuaciones estructurales. Mediante el método, se logra recopilar 1175 artículos de distintas revistas científicas. A partir de estos y con la aplicación de una serie de criterios se identifica una muestra representativa de 421. Los resultados dan cuenta de los constructos, las variables y el tipo de teorías aplicadas en los ambientes virtuales investigados. Por último, la discusión y las conclusiones están referidas a las asociaciones entre los elementos de los modelos publicados por sus autores.

DESCRIPCIÓN DE LA DINÁMICA DE CARBONO EN SUELOS FORESTALES MEDIANTE UN MODELO DE RESERVORIOS

Directory of Open Access Journals (Sweden)

Gustavo Orellana-Rivadeneyra

2012-01-01

Full Text Available Se propone una aproximación sobre variables medioambientales mediante funciones de distribución dependientes del tiempo para simplificar un modelo de la dinámica del carbono orgánico en el suelo. El modelo se basa en el concepto de reservorios, que supone que los diferentes estados de la materia orgánica del suelo constituyen masas homogéneas. Este modelo se enfoca en el intercambio de materia orgánica entre dichas masas, estableciendo relaciones de contacto. Usando el modelo simplificado se calculó la acumulación de materia orgánica en el suelo y la emisión de CO2 desde un ecosistema de bosque de pino (Pinus elliottii ubicado en Gainesville, Florida, EU. Se verificó la viabilidad de las aproximaciones en el modelo para estudiar la dinámica del carbono orgánico en suelos forestales. Se calculó la acumulación relativa de materia orgánica en el suelo. Con esto se obtuvo una estimación de la actividad del bosque de P. elliottii como secuestrador.

Intercalary bone segment transport in treatment of segmental tibial defects

International Nuclear Information System (INIS)

Iqbal, A.; Amin, M.S.

2002-01-01

Objective: To evaluate the results and complications of intercalary bone segment transport in the treatment of segmental tibial defects. Design: This is a retrospective analysis of patients with segmental tibial defects who were treated with intercalary bone segment transport method. Place and Duration of Study: The study was carried out at Combined Military Hospital, Rawalpindi from September 1997 to April 2001. Subjects and methods: Thirteen patients were included in the study who had developed tibial defects either due to open fractures with bone loss or subsequent to bone debridement of infected non unions. The mean bone defect was 6.4 cms and there were eight associated soft tissue defects. Locally made unilateral 'Naseer-Awais' (NA) fixator was used for bone segment transport. The distraction was done at the rate of 1mm/day after 7-10 days of osteotomy. The patients were followed-up fortnightly during distraction and monthly thereafter. The mean follow-up duration was 18 months. Results: The mean time in external fixation was 9.4 months. The m ean healing index' was 1.47 months/cm. Satisfactory union was achieved in all cases. Six cases (46.2%) required bone grafting at target site and in one of them grafting was required at the level of regeneration as well. All the wounds healed well with no residual infection. There was no residual leg length discrepancy of more than 20 mm nd one angular deformity of more than 5 degrees. The commonest complication encountered was pin track infection seen in 38% of Shanz Screws applied. Loosening occurred in 6.8% of Shanz screws, requiring re-adjustment. Ankle joint contracture with equinus deformity and peroneal nerve paresis occurred in one case each. The functional results were graded as 'good' in seven, 'fair' in four, and 'poor' in two patients. Overall, thirteen patients had 31 (minor/major) complications with a ratio of 2.38 complications per patient. To treat the bone defects and associated complications, a mean of

El modelo de trabajo en equipo

OpenAIRE

Iñaki Rodríguez Cueto

2008-01-01

El modelo de trabajo en equipo constituye una herramienta basica en cualquier organizacion que quiera conseguir los objetivos propuestos y, ademas, lo quiera conseguir dentro de parametros de eficacia y calidad.En el entorno de la Comunidad Terapeutica cobra mayor importancia el dominio de saber trabajar en equipo debido a la necesidad de conjugar aspectos psico-terapeuticos, educativos, medicos e, incluso, administrativos a la hora de planificar el tratamiento a nivel grupal e individual.El ...

Asignación del color en modelos tridimensionales

Directory of Open Access Journals (Sweden)

Vicente Domínguez

2011-04-01

Full Text Available Hoy en día los sensores tridimensionales de última generación proporcionan información geométrica con un alto grado de precisión. En el proceso de construcción de un modelo digital, la información colorimétrica es añadida a través de cámaras de color, externas o integradas en el propio sensor 3D. Así, se obtiene una información completa (geometría+color para cada toma de la escena. Sin embargo, la fusión de información de color desde distintos puntos de vista es un problema que los sistemas digitalizadores actuales no resuelven satisfactoriamente. El presente trabajo se centra en el desarrollo de algoritmos que permitan obtener modelos digitales 3D completos, dedicando especial atención al problema de integración de texturas para diferentes posiciones del sensor 3D.

Modelos experimentais de desnutrição e sua influência no trofismo cutâneo

OpenAIRE

Leite,Saulo Nani; Jordão Júnior,Alceu Afonso; Andrade,Thiago Antônio Moretti de; Masson,Daniela dos Santos; Frade,Marco Andrey Cipriani

2011-01-01

FUNDAMENTOS: A pele, para exercer suas funções, necessita de níveis adequados de nutrientes. OBJETIVO: Analisar o trofismo cutâneo de ratos nutridos e desnutridos por meio de dois modelos de desnutrição. MÉTODOS: No Modelo Marasmo, utilizaram-se 60 ratos Wistar em controle dietético, dos quais 30 foram selecionados aleatoriamente para receber metade da dieta diária durante 60 dias. No Modelo Gelatina, empregaram-se 60 ratos, dos quais 30 receberam dieta associada a proteína de baixa qualidade...

Integración de Modelos de Planeamiento y Scheduling en Sistemas de Información Empresariales

OpenAIRE

Vidoni, Melina; Rodriguez, Maria Analia; Vecchietti, Aldo

2016-01-01

La aplicación e implementación de modelos matemáticos tendientes a colaborar con la toma de decisiones no resulta un proceso sencillo y directo: existen diversos factores que dificultan la integración de los modelos matemáticos desarrollados con los sistemas de información empresariales. ERP 2 Optimizer Linkage (E2OL) es un sistema que acopla un modelo matemático al sistema empresarial o ERP utilizado, proveyendo las interfaces necesarias para la adecuada visualización y facilitando el modela...

Contribuições a estudos biológicos com o uso de modelos biofísicos

OpenAIRE

de Cássia Moura do Nascimento, Rita

2004-01-01

Um modelo biofísico é uma representação simplificada e/ou abstrata de processos ou sistemas biológicos. Objetivando ampliar o conhecimento sobre a modelagem biofísica, esta Tese enfoca prioritariamente os modelos que desenvolvemos, visando contribuir com os estudos biológicos. Proteínas transportadoras do tipo canal iônico encontram-se presentes na membrana plasmática de todos os seres vivos e o primeiro modelo biofísico é uma membrana plasmática artificial, na qual há um co...

RoboAct modelo de control autónomo y cooperativo para el Teatro Robótico

OpenAIRE

Peña Santana, Andrés Armando de la

2014-01-01

El teatro robótico es un campo de investigación relativamente joven con un gran crecimiento a futuro. Pensando en esto, este proyecto plantea un modelo que permita desarrollar guiones teatrales para robots, incluyendo potencialidades de nuevas áreas como la robótica móvil, la robótica cooperativa y los robots sociales. Este proyecto presenta un modelo que posee características sobresalientes como la inclusión de ontologías por medio de redes semánticas que representan los modelos relacionales...

Modelos organizativos basados en el conocimiento. Desde la gerencia de la información a la gestión del conocimiento

OpenAIRE

Olmedo Narbona, Antonio

2011-01-01

Esta tesis doctoral estudia la evolución de los modelos de gestión del conocimiento, analizando la relación entre el modelo EFQM y los modelos organizativos basados en el conocimiento. Como aplicación práctica se propone el desarrollo de un modelo organizativo basado en el conocimiento para los Centros del Profesorado, unidades administrativas de la Junta de Andalucía.

ESPECIFICIDADES E IMPORTÂNCIA DE MODELOS MATEMÁTICOS DE QUALIDADE DA ÁGUA

Directory of Open Access Journals (Sweden)

Leandro Fleck

2013-06-01

Full Text Available Como alternativa aos impactos ambientais provenientes do desenvolvimento econômico várias ferramentas de apoio a gestão pública vêm sendo desenvolvidas, onde os modelos matemáticos de qualidade da água merecem especial destaque por apresentarem ampla aplicação no processo de gerenciamento da qualidade dos recursos hídricos. Neste sentido, o presente trabalho tem como objetivo apresentar uma revisão bibliográfica acerca dos principais fatores relacionados à modelagem matemática da qualidade da água de rios. Ao criar um modelo matemático algumas etapas devem ser consideradas para que as informações geradas sejam confiáveis. Dentre as principais etapas, o processo de calibração e validação do modelo se destaca, pois nessas etapas o modelo é confrontado com os dados experimentais e o poder preditivo do mesmo é confirmado. Em geral, a modelagem matemática quando corretamente utilizada por profissionais capacitados, engloba processos químicos, físicos e biológicos de forma simples e eficiente, justificando assim seu uso no controle da qualidade dos recursos hídricos.

Modelo Biomecánico de una Prótesis de Pierna

Directory of Open Access Journals (Sweden)

A.M. Diego Bravo

2014-10-01

Full Text Available Resumen: En este trabajo se presenta el modelo biomecánico de una prótesis de pierna. Con el objetivo de estudiar el cambio de velocidad en la unión prótesis-muñón al momento del impacto del pie con el suelo, está se modeló como un sistema resorte-amortiguador, per- mitiendo evidenciar la necesidad de construir la unión muñón-prótesis con dispositivos de impedancia mecánica variable. Adema's se desarrolló un simulador con el objetivo de hacer representaciones virtuales de un paciente con prótesis. Para ello se modeló al paciente como un robot b́ıpedo planar, el simulador permite estudiar el efecto de las fuerzas de impacto con el suelo de la unión prótesis-muñón como una etapa anterior a la implementación real de la misma. Palabras clave: Marcha humana, Modelo biomecánico, prótesis, simulación.

Estudo comparativo de sete diferentes modelos estatísticos para a característica ganho de peso em bovinos de corte

Directory of Open Access Journals (Sweden)

Fernandes Henrique Dorneles

2000-01-01

Full Text Available Foram analisadas uni e bivariadamente as características ganho de peso do nascer à desmama e ganho de peso pós-desmama de 4883 animais, filhos de 328 touros da raça Charolês, com o objetivo de comparar diferentes modelos ao considerado mais completo, porém de mais difícil aplicabilidade. Os modelos estudados foram o MA1, modelo animal que inclui os efeitos genético direto do animal e genético materno; MA2, modelo animal que inclui o efeito aditivo direto do animal e o efeito de ambiente permanente; MA3, que inclui os três efeitos já citados (considerado o "melhor"; MA4, modelo animal que inclui apenas o efeito aditivo direto; MTV, modelo touro-vaca que inclui o efeito genético direto do pai, além dos efeitos genéticos materno e de ambiente permanente; MT1, modelo touro com efeito genético aditivo direto do pai e efeito de ambiente permanente; e MT2, modelo touro com apenas efeito direto do pai. Com base nos resultados, observou-se diferença estatística somente entre os modelos MA4 e MT2, em relação ao MA3, para o ganho de peso do nascer à desmama. Concluiu-se que, para a característica pré-desmama, a inclusão de pelo menos um dos efeitos (genético materno ou ambiental foi indicada, enquanto para a pós-desmama até mesmo modelos mais simples como o MA4 e o MT2 podem ser utilizados para substituir o modelo mais complexo (MA3. As análises bivariadas são indicadas, principalmente por apresentarem as correlações genéticas entre as características.

Market segmentation in behavioral perspective.

OpenAIRE

Wells, V.K.; Chang, S.W.; Oliveira-Castro, J.M.; Pallister, J.

2010-01-01

A segmentation approach is presented using both traditional demographic segmentation bases (age, social class/occupation, and working status) and a segmentation by benefits sought. The benefits sought in this case are utilitarian and informational reinforcement, variables developed from the Behavioral Perspective Model (BPM). Using data from 1,847 consumers and from a total of 76,682 individual purchases, brand choice and price and reinforcement responsiveness were assessed for each segment a...

Evaluating the effect of different draw solutes in a baffled osmotic membrane bioreactor-microfiltration using optical coherence tomography with real wastewate

KAUST Repository

Pathak, Nirenkumar

2018-05-03

This study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor for real sewage employing baffles in the reactor. To study the biofouling development on forward osmosis membranes optical coherence tomography (OCT) technique was employed. On-line monitoring of biofilm growth on a flat sheet cellulose triacetate forward osmosis (CTA-FO) membrane was conducted for 21 days. Further, the process performance was evaluated in terms of water flux, organic and nutrient removal, microbial activity in terms of soluble microbial products (SMP) and extracellular polymeric substance (EPS), and floc size. The measured biofouling layer thickness was in the order sodium chloride (NaCl) > ammonium sulfate (SOA) > potassium dihydrogen phosphate (KH2PO4). Very high organic removal (96.9±0.8 %) and reasonably good nutrient removal efficiency (85.2±1.6 % TN) was achieved. The sludge characteristics and biofouling layer thickness suggest that less EPS and higher floc size were the governing factors for less fouling.

Noise destroys feedback enhanced figure-ground segmentation but not feedforward figure-ground segmentation

Science.gov (United States)

Romeo, August; Arall, Marina; Supèr, Hans

2012-01-01

Figure-ground (FG) segmentation is the separation of visual information into background and foreground objects. In the visual cortex, FG responses are observed in the late stimulus response period, when neurons fire in tonic mode, and are accompanied by a switch in cortical state. When such a switch does not occur, FG segmentation fails. Currently, it is not known what happens in the brain on such occasions. A biologically plausible feedforward spiking neuron model was previously devised that performed FG segmentation successfully. After incorporating feedback the FG signal was enhanced, which was accompanied by a change in spiking regime. In a feedforward model neurons respond in a bursting mode whereas in the feedback model neurons fired in tonic mode. It is known that bursts can overcome noise, while tonic firing appears to be much more sensitive to noise. In the present study, we try to elucidate how the presence of noise can impair FG segmentation, and to what extent the feedforward and feedback pathways can overcome noise. We show that noise specifically destroys the feedback enhanced FG segmentation and leaves the feedforward FG segmentation largely intact. Our results predict that noise produces failure in FG perception. PMID:22934028

Moldes contrários: o romantismo como modelo (negativo) para o naturalismo

OpenAIRE

DA SILVA, Alan Victor Flor; SALES, Germana Maria Araújo

2014-01-01

Modelos negativos são paradigmas com os quais não desejamos ser comparados, aos quais queremos nos contrapor ou dos quais esperamos ser diferentes. Considerando-se, portanto, esse conceito, a partir dos romances O Mulato (1881), de Aluísio de Azevedo, A Normalista (1893), de Adolfo Caminha, e Hortência (1888), de Marques de Carvalho, objetivamos, com este trabalho, demonstrar que os idealizadores do Naturalismo no Brasil atribuem ao Romantismo, ainda que de forma negativa, a função de modelo....

Modelo POE en la simulación por computador de sistemas complejos

Directory of Open Access Journals (Sweden)

Jorge Eduardo Ortiz Triviño

1999-07-01

La idea central es simular características de los seres vivos, tales como su capacidad de decisión y acoplamiento al entorno. Con este fin surgió el MODELO POE, que integra tres características biológicas interesantes: Philogenia (evolución, Ontogenia (diversidad y especialización, y Epigenia (aprendizaje. En este artículo se explica el surgimiento y la filosofía del MODELO POE y su aplicación directa en ciencias de la computación.

Estandarización de modelo experimental porcino para defectos óseos maxilares

OpenAIRE

A.F. Aguilera-Salgado; M.R. Pérez-Dosal

2014-01-01