Powered by
Teklogin
copyright 2004©
www.prlsamp.org
|
Enginnering |
|
González, Luis |
Rodríguez-Sanabria, Doeg |
González, Luis*UPR-Mayagüez, Moreno, Pedro, Civil Engineering, Vega, Héctor, Carrasco, Emmanuel, Vargas, Javier, Santos, Jeannette; General Engineering, Acosta, Felipe; Civil Engineering, UPR-Mayaguez.
Evaluation of Concrete Properties Using Thermosetting Polymer as Aggregate
Many daily-life products are manufactured using thermosetting polymers. As a consequence, great amount of scrap material is disposed to landfills because the thermosetting nature of the polymer does not allow their reuse. This situation creates an extra expense to manufacturers for the material’s disposal and it creates an environmental problem since it will take approximately five hundred years to biodegrade in landfills. An alternate use of these polymers is as aggregates for concrete mixes. Previous works have shown that substituting between 5 to 10 percent of the fine aggregate by polyethylene and paper phenolic reduce the strength of concretes within the allowable tolerances. The purpose of this study is to expand the available work by investigating the effect on the mechanical properties of concrete mixes containing a wider variety of thermosetting polymers as fine aggregate substitute. Several mixes are designed; varying the proportions of the polymer from 0% to 15% percentage. Standard cylinder specimens are cased to evaluate their compressive strength, having a control mix as base for comparison. Also the permeability of the mix is assessed since this variable has a direct relationship with concrete durability.
Hermida, Cristina*UPR-Mayagüez, Civil Engineering;
Integration of the Tren Urbano systen to the Carolina Municipality
Tren Urbano (TU) is the new and innovative mass public transportation system under construction in Puerto Rico. TU is a heavy rail, automated metro system designed to serve the congested San Juan Metropolitan Area (SJMA), which generates more than 3.2 million vehicular trips per day. This system will be the key factor in the mass transportation plan that the Department of Transportation and Public Works (DTPW, 2002) has for the SJMA. The integration with the existing transit services is a crucial element to create the expected acceptance of the general public. Each municipality the train is projected to serve has its own characteristics and their recognition and consideration will create an effective transit system. Among the future extensions considered are the municipalities of Caguas, Old San Juan, and Carolina via Luis Muñoz Marin Airport and via “65 de Infanteria” Avenue. Numerous feasibility studies have identified Carolina as a mayor activity center and a fundamental part of the TU Master Plan. This municipality has exclusive characteristics that make it an excellent origin and destination for many riders that wish to arrive to the SJMA, including schools, industries and shopping centers as well as numerous housing developments conveniently located along the projected project corridor.
The Carolina municipality is a very dense inhabited area integrated to the SJMA. This municipality is also known as the industrial capital of Puerto Rico because of the countless industries located within city limits. The main arterial road that crosses the municipalities of Rio Piedras and Carolina from East to West is called “Regimiento 65 de Infanteria” (PR-3). The stretch of the “65 de Infanteria” Avenue from Rio Piedras to Carolina Judicial Center (Centro Judicial de Carolina, CJC) has an urgent need for the implementation of an effective transit system to ease the asphyxiating traffic congestion that affects the roads of this municipality. The problem worsens during the peak-hour with the invasion of commuters form adjacent municipalities who depend on this main road to arrive to the SJMA, and to the abundant educational facilities and industrial parks conveniently located in Carolina, including pharmaceutical, electronics and textiles manufacturers, shopping centers, etc.
The transportation system in this municipality needs extensive improvements for the system to be effective integration with existing transit service is imperative. Currently the Metropolitan Bus Authority (AMA) has five routes that serve the Carolina community from 8 am to 9 pm. There is also a público service (jitney) that transports passengers to numerous parts of the SJMA and adjacent municipalities. These drivers work to satisfy the demand and do not have fixed schedules. The past year the DTOP signed an agreement between the leaders of this authorities that will guarantee a cooperation between all agencies. The unification of the TU, AMA buses, and públicos will provide the urgently needed dependable transit service. This research will identify the deficiencies of the current transit facilities and provide improvement plans by evaluating system providers as well as the potential riders, including all the special communities located along the TU alignment. It will provide the needed integration plan of these services in order for the TU to be a complete success, and satisfy the demands of the Puerto Rican community.
Marín, José Xavier*UIA-Bayamón, Engineering Department, Inter American University of Puerto Rico, Bayamón Campus; Díaz, Otoniel Mechanical
Dynamic Analysis of Rockets
Numerous mathematical models exist to describe the trajectory of a rocket during its travel trough the atmosphere. Most of them disregard the variation of gravity and density with altitude because increase the number of non-linear terms in the equation of motion. The purpose of this research is to develop a high precision mathematical model to describe the kinematics (position, velocity and acceleration) of a rocket trough the atmosphere. Factors such as variation of gravity, variation of air density, variation of fuel mass, and variation in the drag force are taken into account in order to achieve an excellent approach of what it will be in the real world. Because of the complexity of the equation of motion the Taylor Differential Transform method is used in order to manipulate the non-linear terms easily. The algorithm developed is programmed in MATLAB. As a result, the program plots the position, velocity and acceleration of a particular rocket. Later on, the model will be compared with the results obtained launching a model rocket with an altimeter device inboard.
Martínez, Néstor*UPR-Mayag, Engineering/University of Puerto Rico,Mayaguez Campus; Donovan, James Mechanical and Industrial Engineering, University of Massachusetts Amherst Calcagno, Bárbara General Engineering, University of Puerto Rico-Mayaguez
The Effect of Specimen Size and Strain Induced Crystallization on Unstable Fracture of Natural Rubber
Natural Rubber (NR) crystallizes when it is strained, consequently improving it resistance to crack formation and propagation. The specific conditions for crack instability depend on the energy release rate of the total system. This rate is determined by the degree of crystallization and specimen size. Therefore, the effect of specimen geometric configuration and the material's ability to strain crystallize on the conditions for unstable crack growth will be studied. The ability of NR to strain crystallize can be controlled by the concentration of carbon black, a widely used impurity to improve the resistance of rubber to fatigue, fracture and wear failures. The extent of crosslinking will also determine the material's ability to strain crystallize. The resistance of rubber to crack growth will be measured by using a tension test machine to study samples with intentionally induced cracks in different configurations: edge crack (single and double side cracks) and center crack. Tearing test techniques will be used to consider the application of pure shear stress. The fact that the rubber's fracture energy is function of the sample's dimensions, length and width, and the cracks length, will be considered. This is an important and practical problem to understand the conditions for unstable crack growth in rubber, and relevant for
understanding recent rubber failures.
Moreno, Pedro*UPR-Mayagüez, Civil Engineering; Gonzalez, Luis, Vega, Hector, Carrasco, Emmanuel, Vargas, Javier, Acosta, Felipe, Santos, Jeannette, General Engineering, UPR-Mayagüez
The Study of Thermoplastic Polymers as Aggregate and its Effect on Concrete Properties
The purpose of this research is to study how the uses of polymers affect the strength of the concrete. Finding a possible alternative for the recycling of materials such as Polyvinyl Chloride (PVC) and polycarbonate. Fine and coarse aggregates of concrete mix are replaced by chosen sizes of polymers in different proportions, which for one of them has been studied previously. It is desired to optimize what size gives the best substitution. It is also wanted to establish a correlation between the properties of the polymers such as Tensile Strength with the change in the strength of the concrete. This is accomplished by the use of the same experimental condition, but with different thermoplastic polymers. Also, the permeability of the mix is assessed since this variable has a direct relationship with concrete durability.
Perales Sellés Rafael*UPR-Mayagüez, Mechanical Engineering; Jia, Yi,
Development of Smart Orthodontic Devices
Medical technology continues to advance rapidly as physicians and engineers move closer to and understand better each other's needs. There are more and more evidences that various engineering tools can be applied to biomedical and biomechanics research projects. The objective of this proposed research topic is to introduce engineering modeling and analysis tools and micro sensors technologies into biomedical engineering and biomechanics with particular interests in the development of smart orthodontic devices. During the project, the students will (1) develop a FE model to stimulate the performance of the orthodontic device, (2) integrate micro stress sensors into the orthodontic devices to monitor the tooth movements during active treatment and the performance of the device.
Rodríguez, Griselle*UPR-Mayagüez, Engineering; Ramirez, Nazario Industrial Engineering, UPR Mayaguez
Estimación de Parámetros de Calidad de Agua del Río Guanajibo
El propósito de la investigación es encontrar un modelo matemático para predecir doce parámetros de calidad de agua del río Guanajibo y Yaguez. Para esto fue necesario ordenar datos desde 1973 al 2001 de 4 estaciones. Este proceso fue sumamente tedioso y complicado debido a la cantidad de datos. La tarea de ordenar los datos fue culminada, utilizando principalmente el programa Microsoft Excel. Luego de ordenados los datos se procedió a buscar los modelos para los parámetros de las estaciones comenzando con la estación 50136400 del río Guanajibo. La búsqueda de estos modelos se lleva a cabo utilizando los programas “Statgraphics” y “Matlab”. Los parámetros se escogen en orden para así poder comparar el parámetro en cuestión con el anterior. También se utilizan datos de otras estaciones (en este caso las distintas estaciones del río de Añasco), para así encontrar un modelo que provea un estimado lo más parecido a las observaciones. Se pretende encontrar modelos satisfactorios que expliquen el 60% o más de la variabilidad total. Para identificar el modelo se deben eliminar los “outliers”, estos son datos incorrectos que no revelan el comportamiento normal del proceso. Luego de obtener el modelo utilizando “Statgraphics” se procede a probarlo. Esto se hace en otra aplicación de “Statgraphics”. Por último, se utiliza “Matlab” para obtener estimados de observaciones que no se realizaron. Se deben comparar los datos que ya están, con los encontrados para ver si concuerdan los unos con los otros. De ser así se sustituyen los espacios vacíos con los estimados. Si no concuerdan los datos se procede a buscar otro modelo. Estos pasos se repiten para cada parámetro de cada estación.
Rodríguez-Sanabria, Doeg*UPR-Mayagüez, Electrical Engineering; O'Neill-Carrillo, Efraín
Education Modules for Distributed Generation in Power Systems
This paper presents an effort to develop education tools that illustrate the benefits, as well as the problems related to Distributed Generation. This work is the result of an undergraduate research project at the University of Puerto Rico-Mayagez (UPRM). The education modules include theoretical discussions of interconnection issues, and the modeling of DG in distribution networks. The emphasis was on protection systems and the analysis of alternate ways to configure protective devices at the distribution level. Economic aspects of DG were also considered. The Alternative Transients Program (ATP) and PowerWorld were used to develop an environment to study DG and create visual aid tools and materials. These modules are being developed at UPRM, not only for academic use, but also as a demonstration and orientation tool for thepublic, Pre-college students and professionals. It is the aim of this work to clarify DG concepts and help answer basic questions about the technologies involved in a simple, understandable manner.
Santiago, Marianela*UPR-Mayagüez, Eléctrical Engineering; Carlos Torres, Dr. Efraín O'Neill-Carrillo
Simulation of Power Electronics Systems in Power Systems Studies
Modeling and simulation of power electronics in power systems is usually centered on the interaction between the converter and the system. In general, there is no need to use detailed device models. For steady state studies, a simple model is enough to assess the impact on the system. However, system dynamic performance requires detailed modeling of control loops and device firing. To study the effects of power electronics in the utility system, all sensitive loads must be included. Models are also more involved for harmonic propagation and resonance since all nonlinear components, capacitors and filters must be included in the model. This paper presents the first stage in the effort to implement a software environment for power quality studies that includes the level of detail necessary to assess power electronics impact in power systems.
Santos, Abigail*UPR-Mayagüez, Mechanical Engineering;
Analyzing the Parts Behavior in a Vibratory Bowl Feeder to Predict the Dynamic Probability Profile
The vibratory bowl feeder is used in automated assembly to sort and orient variety of parts. To design a part feeder the engineer needs knowledge related to the tendency of the parts to fall in different positions or aspects as well as the complexity of the feeder, and the number of parts. Currently, the design of a feeder is based in heuristics rather than sound manalytical models. The investigation proposes the development of a model that predicts the influence or the effect of the vibration amplitude in the orientation efficiency. For that reason, the model will be based on the identified parameters, such as part’s geometry and part’s orientation at the end of the bowl feeder, to optimize the design and performance of the vibratory bowl feeder.
In addition, experiments will be conducted using five different parts in the bowl feeder test-bed to estimate the probabilities that the parts have when resting in all possible aspects while moving through a surface in movement. The set of these probabilities is called the Dynamic Probability Profile. With these experiments, any deviation between the Dynamic Probability Profile and the Static Probability Profile obtained from static models and static experiments will be compared. These experiments will provide information that will help in the development of the model. This paper summarizes the status of the investigation so far.
Ubaldo Córdova*UPR-Mayagüez, Chemical Engineering Department; Berrios, María E.,
Conklin, Lourdes, Rodríguez, Melissa, Méndez, Rafael , Cardona-Martínez, Nelson
Synthesis and characterization of binary and ternary nanoparticle oxide for the photocatalytic oxidation of Toluene using UV and visible light
Conventional semiconductor photocatalysts utilize UV light, typically generated by lamps, for electronic excitation. The UV portion of the solar spectrum is less than 10% of the total energy output from the sun. The potential of appropriate semiconductor nanoparticles to absorb in the visible range offer a significant incentive for further study because not only the additional light intensity should improve the efficiency of the photocatalytic processes but also the use of solar radiation will reduce fossil fuel consumption. This effect is not be possible by using only TiO2, because bulk titania absorbs light in the near UV region at about 390 nm and as the particles get smaller they will absorb light at even lower wavelengths. For bulk TiO2, only about 3% of the solar spectrum can be harvested. An interesting approach for achieving a better charge separation and an enhancement in the process of hole trapping in semiconductor particulate systems involves the coupling of two semiconductors with different energy levels.
The study proposed here includes the systematic study of the synthesis, characterization, and photocatalytic oxidation of toluene of a series of WO3-TiO2, WO3-SiO2-TiO2, MoS2-TiO2, MoS2-SiO2-TiO2, and Fe2O3-TiO2 sol-gel based catalysts. The catalysts will be synthesized using the traditional sol-gel preparation method with a variation that involves the use of organic as well as inorganic precursors for the WO3 containing samples and a modification of the method described by Wilcoxon for the MoS2 containing photocatalysts.
Vargas, Osvaldo*UPR-Mayagüez, Civil Engineering; Esquilín, Omar, Acosta, Felipe
Mechanical Properties of Concrete Masonry Blocks with Recycled Tire Rubber as Aggregates
Presently in Puerto Rico more than 4 million automobile tires are rejected and disposed annually, of which approximately 800,000 are recycled. This situation creates serious environmental and health problems, such as the spreading of mosquitoes and other vermin, pose fire hazard, and reduce the life-span of land-fills. Finding alternate uses for the rubber material of both the disposed and recycled tires can greatly alleviate these problems. Therefore, the purpose of this research is to investigate the effect on the mechanical properties of concrete blocks when recycled tire rubber is used to substitute part of the aggregates. This study complements the limited amount of information available in the literature related to the subject. Results from this work will serve as the bases for future investigation to eventually develop design and construction guidelines. The experimental program consists of evaluating the engineering properties of the masonry concrete blocks with the recycled tire rubber by performing compression and flexural test on masonry prisms following the procedures of the ASTM standards. The results are compared with control specimens made of conventional masonry units. An insignificant reduction of the strength is expected since the proportions of the rubber in the mix are not to exceed the 20% to 25% of the total aggregate volume reported by previous works as critical quantities that significantly affect performance.