Development of an Electro-Centrifugal Spinning Setup for Nanofiber Production Research

Nanofiber production methods have been developed and improved over the course of decades. Each process allows for the creation of fibers with distinct properties that provide benefits to growing number of applications. On the same note, every process has shortcomings that keep them from being universally valid for all applications. This research considers electrospinning and centrifugal spinning systems and attempts to create a process which maintains high fiber qualities like small and consistent fiber diameters, and improved fiber alignment while providing a high fiber yield. The electro-centrifugal (EC) spinning machine that resulted was designed utilizing computer aided design (CAD) software to create crucial components and 3D print them with unique specifications that will help with vibration reduction, improved modularity, and facilitate cleaning procedure. When tested using 8 wt% polyethylene oxide (PEO) solution in deionized water (DI H2O), the machine was able to produce fibers at 2000, 3000 and 4000 rpm each run with a 0 V, 2000 V and 4000 V potential input. The produced fibers were measured using a scanning electron microscope (SEM) and ImageJ software. The tests showed that adjusting input voltage to higher values improved fiber quality and increased fiber yield. Increasing rotational velocity greatly increased fiber yield but increased fiber diameters. The results showed promise for future testing procedures that could be fine-tuned to produce fibers within the nanometer range (1 – 100 nm)

Offshore CO2 storage resource assessment of the northern Gulf of Mexico (Texas-Louisiana)

The Offshore CO2 Storage Resource Assessment of the Northern Gulf of Mexico (Texas-Louisiana) project (a.k.a., "TXLA" study) supports Goals 3 & 4 of the DOE NETL Carbon Storage Program Plan by aiding industry's ability to predict CO2 storage capacity in geologic formations to within +/- 30%. This is achieved by assessing potential regional storage formations in the State and federally regulated portions of the Gulf of Mexico. The objective of the project was to conduct an offshore carbon storage resource assessment of the Gulf of Mexico, Texas — Louisiana study area. This was accomplished by: 1. Assessing the carbon dioxide (CO2) storage capacity of depleted oil and natural gas reservoirs utilizing existing data (well logs, records and sample descriptions from existing or plugged/abandoned wells, available seismic surveys, existing core samples, and other available geologic and laboratory data) from historical hydrocarbon industry activities in the heavily explored portions of the inner continental shelf portions of the Texas and Louisiana Gulf of Mexico coastal areas. 2. Assessing the ability and capacity of saline formations in the region to safely and permanently store nationally-significant amounts of anthropogenic CO2 using existing data. Additionally, the study identified at least one specific site with the potential to store at least 30 million tonnes of CO2, which may be considered in the future for commercial or integrated demonstration projects. The study also engaged the public and other stakeholders in the region through outreach activities to apprise them of the study objectives and results.Bureau of Economic Geolog

Comparing carbon sequestration in an oil reservoir to sequestration in a brine formation-field study

Geologic sequestration of CO2 in an oil reservoir is generally considered a different class than sequestration in formations which contain only brine. In this paper, the significance and validity of this conceptualization is examined by comparing the performance of CO2 injected into a depleted oil reservoir with the performance of similar injection into non-oil bearing sandstones using a field test at Cranfield Field, Mississippi as a case study. The differences considered are: (1)Residual oil in the reservoir slightly reduces the CO2 breakthrough time and rate of pressure build up as compared to a reservoir containing only brine, because under miscible conditions, more CO2 dissolves into oil than in to brine. (2)Dense wells provide improved assessment of the oil reservoir quality leading to improved prediction as well as verification of CO2 movement in this reservoir as compared to the sparsely characterized brine leg. The value of this information exceeds the risk of leakage. Assessment of the difference made by the presence of residual oil requires a good understanding reservoir properties to predict oil and gas distribution. Stratal slicing, attribute analysis and petrographic analyses are used to define the reservoir architecture. Real-time pressure response at a dedicated observation well and episodic pressure mapping has been conducted in the reservoir under flood since mid-2008; comparison measurements are planned for 2009 in down-dip environments lacking hydrocarbons. Model results using GEM compositional simulator compare well in general to measured reservoir response under CO2 flood; imperfections in model match of flood history document uncertainties Time laps RST logging is underway to validate fluid composition and migration models. Monitoring assessing the performance of the wells during the injection of CO2 suggests that the value of wells to provide field data for characterization exceeds the risk of leakage.Bureau of Economic Geolog

Fluid net models: from behavioral properties to structural objects

Increasing the production in manufacturing systems is one of the main demands in modern systems. The naive approach that this goal can be achieved when more or faster resources are used is not always valid. In fact, the complex interactions among system’s elements may lead to paradoxical behaviors; for example, using faster machines could reduce the equilibrium throughput (number of part fabricated per unit time in steady state) of the system, or even worse, block all system activities, reducing it to zero. This work leverages the concepts about fluidization and analysis techniques used in Timed Continuous Petri nets (TCPN) presented in earlier works to study the behavior of the equilibrium throughput when more/faster machines are used. Herein, we illustrate how discontinuities induced bifurcations of the equilibrium throughput are due to the existence of paths that can increase/decrease the marking of certain subnets. In particular, if paths gaining/losing tokens are fired without a particular balance, then the equilibrium throughput exhibits discontinuities since the equilibrium marking loses hyperbolicity. Moreover, these discontinuities imply other undesired throughput behaviors; for example, the existence of non-monotonicities of the equilibrium throughput (when more/faster resources are used in the system, its equilibrium throughput is reduced). The discontinuities together with a homothecy property are used to explain non-monotonicities in the equilibrium throughput. A relevant aspect is that these undesired system behaviors appear when the net has structural objects named problematic configurations that are associated with certain subnets in which there are no P-semiflows. Although the number of these configurations increase exponentially in the size of the net, some reduction rules are introduced to remove configurations, while the problematic ones are kept (or can be recovered) in the reduced net. This saves computation time in the analysis and, more importantly, provides useful insights about the root of undesired behaviors. This work focus on systems that can be modeled with fluid (or continuous) mono T-semiflow Timed Continuous Petri nets. Even if under certain constraints, they are capable of capturing many characteristics of modern systems, such as interleaving of cooperation and competition

Structural Sequence Detectability in Free Choice Interpreted Petri Nets

This paper is concerned with the structural sequence detectability problem in Free Choice Interpreted Petri nets, i.e. with the possibility of recovering the firing transition sequence in Free Choice Interpreted Petri nets using the output information when the initial marking is unknown. Based on the Free Choice Interpreted Petri net structure, three relationships are proposed which are devoted to capture the confusion over the transitions. These relationships depend on interpreted Petri nets structures such as T-invariants, P-Invariants, attribution and distribution places. Thus, the approach herein presented exploits the interpreted Petri nets structural information in order to determine the structural sequence detectability of an interpreted Petri net.Consejo Nacional de Ciencia y Tecnologí

Análisis del consumo de cerveza en el área metropolitana de Monterrey: Un modelo de respuesta censurada

This study analyses the effect of household income and socioeconomic composition on household expenditure on beer. Tobit models are used in order to capture the response on the magnitude of beer purchases as well as the behavior of non-purchasing households. The results indicate, without regard to income segment, that household income and education of the household manager determine beer consumption and have a greater effect on potential consumers.

Energy-Efficient Thermal-Aware Scheduling for RT Tasks Using TCPN

This work leverages TCPNs to design an energy-efficient, thermal-aware real-time scheduler for a multiprocessor system that normally runs in a low state energy at maximum system utilization but its capable of increasing the clock frequency to serve aperiodic tasks, optimizing energy, and honoring temporal and thermal constraints. An off-line stage computes the minimum frequency required to run the periodic tasks at maximum CPU utilization, the proportion of each task''s job to be run on each CPU, the maximum clock frequency that keeps temperature under a limit, and the available cycles (slack) with respect to the system with minimum frequency. Then, a Zero-Laxity online scheduler dispatches the periodic tasks according to the offline calculation. Upon the arrival of aperiodic tasks, it increases clock frequency in such a way that all periodic and aperiodic tasks are properly executed. Thermal and temporal requirements are always guaranteed, and energy consumption is minimized