bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoeconomic Model for the Energy Optimization of Industrial Air Compressed Supply Network Under Transient Condition
Authors: Corredor M. Lesme , Guillen Diego , Prada José , Contreras Alisson 
Published: October 2013

Air compression represents around 20% of industrial total electric power demand, especially in chemicals and process companies. Few technical studies related with energy optimization of air compressed networks are reported in the specialized literature, in contrast, in natural gas and steam networks have been widely analyzed. Pressure, temperature and flow monitoring of air compression is not enough for implementation of energy optimization models, for this reason authors have developed a transit conditions model which takes into account air supply equipments and air compressed process requirements. This paper presents a decision support system for the scheduling selection of a set of air compressors in an industrial plant based on energy demand minimization.
Several constraints must be taken in consideration during the optimization process, this can be desegregate in two types, the first set of constrains was used for simulate the operation of scroll, screw and centrifuges compressors, the second based in graph an node theory and contain the mathematical transit conditions model of supply air network topology, for the complexity of the problem the use of a genetic algorithm to search an optimal combination was necessary.
The Complementary Nature of CO2-Plume Geothermal (CPG) Energy Production and Electrical Power Demand
Authors: Adams Benjamin M. , Kuehn Thomas H. 
Published: October 2013

CO2 Plume Geothermal (CPG) energy generation is a renewable technology that uses CO2 as the geologic working fluid within naturally permeable, sedimentary thermal reservoirs. In this paper, we compare the ability for CPG geothermal technology to meet electrical demand requirements, compared with other renewable technologies, for a 10MW, northern climate town near Minot, North Dakota. Wind and solar are both supply-driven technologies, capturing energy when it is available; However CPG is demand-driven—the rate at which energy is removed from within the earth is chosen to meet electrical demand. Using meteorological data, we compare estimated system performance with actual 2010 electrical load to gage each system’s ability to meet demand.
CPG is found to most closely match system demand during the three-season (fall, winter, spring) year, where solar production is inversely related to demand. At the same time, wind does not track demand during any portion of the year, consistently having a large variability. None of these renewable technologies was found to track demand all year. Ultimately we show that CPG may be used to reliably track hourly demand during 95% of the year—an unattainable result for wind and solar.
Energy Use Comparison of Air Distribution Systems Serving a Section of a School Building
Authors: Jordan Stillman , Manteufel Randall D. 
Published: October 2013

An optimal air distribution design accomplishes both comfort and ventilation requirements while consuming as little energy as possible. This paper analyzes four different air distribution systems and technologies including single duct variable air volume air handlers, chilled beam cooling systems, total energy recovery wheels, displacement ventilation, and dedicated outside air systems; in an effort to determine the best air distribution system for a representative section of a school in hot and humid climate. The effectiveness of the air distribution systems is evaluated by analyzing how the different technologies take advantage of the natural convective properties of air to create a comfortable environment for the occupied region of the space. Distribution effectiveness and energy consumption must be weighed against considerations such as system complexity and ease of operation.
This paper compares several alternative air distribution systems to a baseline single inlet VAV system that is commonly used in new schools designed today. Calculations show that the total energy recovery wheels result in a 16% energy savings over the baseline air distribution system because of the large amount of outside air required in school buildings. Chilled beams are not well suited for schools because of the large amount of outside air required by the space and the sophisticated design and operation needed to prevent condensation from occurring at the chilled beam. The results show that the air distribution system that consumes the least amount of energy is a displacement ventilation system. The system also inherently promotes better indoor air quality as it allows air to naturally rise out and return out of the space with minimal mixing of contaminates that may be recirculated within the room for others to breath. The displacement ventilation system’s overall energy savings of 20% over the baseline is mainly attributed to its total energy recovery wheel and the system’s ability to drastically reduce the cooling load seen by the air cooled chiller by effectively ventilating spaces using less outside air.
Learning Outcomes From Design of Wind Turbines Carried Out by Underserved High School Mentees Participating in DREAM
Authors: Valley Kyle J. , Nguyen Leslie Q. , Rodela Alejandro , Houchens Brent C. 
Published: October 2013

The fall 2011 DREAM design project required teams to design and build a working wind turbine. The turbines were tested at three wind speeds, with the most points awarded for power production at the lowest speed, forcing mentees to optimize their blade designs. The Pre-engineering Concept Inventory (PCI) and Intuition Inventory (II), which focus on wind energy, were used to measure pre- and post-content knowledge of high school mentees. The use of mini-lectures to convey content simultaneously with design is discussed.
The Inventories show that participation in DREAM generally increases mentees’ understanding of wind energy concepts. However, insufficient mathematics foundations hamper their ability to understand algebraic representations and evaluate numerical predictions. Results provide feedback on current practices and help pinpoint specific areas for improvement to increase the efficacy of DREAM in future years.
Enhancement of Forced Convection in Ribbed Channels by Nanofluids
Authors: Manca O. , Nardini S. , Ricci D. 
Published: October 2013

The enhancement technologies in convection heat transfer allow the effectiveness improvement of heat exchangers. The employment of rough surfaces could be taken into account. In fact, in a ribbed channel, turbulators break the laminar sub-layer and create local turbulence in order to reduce the thermal resistance and augment heat transfer rates. Another available technique is represented by the introduction of nanoparticles in the base fluids in order to improve the fluid thermal conductivity. However, both the methods provide increasing pressure drops.
In this paper a numerical investigation is carried out on water-Al2O3 nanofluid forced convection in a two-dimensional ribbed channel, heated by a constant heat flux. Ribs have trapezoidal shapes and different geometric arrangements were analyzed. The mixture model was employed in order to describe the nanofluid behaviour and different nanoparticle volume fractions were considered. The aim consists into describe the thermal and fluid-dynamic performances of ribbed channels filled with Al2O3/water based nanofluids in the turbulent regime. Results show increasing heat transfer rates as particle concentrations and Reynolds numbers increase but higher required pumping powers.
FEM Analysis of the Effects of Cooling Techniques on the Microstructure of Aluminum 7075 Friction Stir Welded Joints
Authors: Kheireddine A. H. , Ammouri A. H. , Hamade R. F. , Kridli G. T. 
Published: October 2013

Friction stir welding (FSW) is a proven solid-state technique for joining metal alloys. Given the low melting temperatures of light alloys, excessive heat build-up in such joints may have undesirable consequences such as melting and/or undesired grain growth. It is widely recognized that the resulting mechanical properties of a welded joint depends to a great extent on microstructure development.
The aim of this paper is to improve the microstructure of friction stir welded aluminum alloy joints by utilizing two different cooling techniques. To this end, a 3D FEM model is developed to simulate the friction stir welding plunging and advancing phases. The parameters used in the FEM model were optimized for minimum simulation time and resulting in accurate simulations as compared with experimental results previously published by other workers. The work material was modeled as a visco-plastic material and dynamic recrystallization was implemented and added to the material model. Two main cooling techniques were compared: temperature controlled backing plate and another via cryogenic CO2 direct nozzle. The monitored output parameters were: temperature, stress, strain, and strain rate. Consequently, values of the Zener-Hollomon parameter, Z, were calculated and the resulting grain size distribution in the joint was found. Due to dynamic recrystallization, nano-sized grains were predicted to be generated in the cryogenically cooled weld line when compared to non-cooled one.
FEA Robustness Verification in the Modeling of 1-D Stress Wave Propagation for a Split Hopkinson Bar (SHB) Test
Authors: McCoy Michael L. , Moradi Rasoul , Lankarani Hamid M. 
Published: October 2013

Impact loading on mechanical structures and components produces stress conditions that are large in magnitude and fluctuate with time which are difficult for the engineer to assess for design. The Stress Wave Propagation (SWP) is a classical methodology to account for these large stress levels. Due to the highly mathematical approach of stress wave theory along with consideration of boundary conditions interactions in the struck solid, the stress wave propagation method generates closed solutions to impact problems that are only 1-D in nature [1, 2]. In engineering practice, most mechanical problems are more complex than 1-D and thus numerical methods need to be applied to provide engineering solutions. The Finite Element Method (FEM) is a numerical technique that is commonly used in static and dynamic loading conditions to provide engineering solution to complex geometry and loading. In this paper, the FEM is examined to determine if this methodology is robust enough to accurately represent Stress Wave Propagation in solid mediums by the capturing wave propagation velocities, boundary reflections and transmissions along with large transient stress magnitudes using simple 2-D axisymmetrical elements. The most complex 1-D problem and perhaps the most practical solved problem by the Stress Wave Propagation is the Split Hopkinson Bar (SHB) test. The purpose of this test is to determine the dynamic strength of materials. A finite element (FE) model of an as-built SHB test apparatus was developed. In the same function as the strain gages, two nodes were used to extract the strain time histories from the FE model of the apparatus bars. It was found that the pseudo-strain gages of the FEA compared well to the SWP theory. The pulse magnitudes of strains, strain rates and stress were found extremely similar and exhibited magnitudes within 4% between SWP and direct examination.
This model replicating a dynamic impact event demonstrated that the FEA can be used to solve complex impact problems involving stress wave propagation with the use of simple 2-D axisymmetric elements reducing computation time.
Vibration Control of Relative Tool-Spindle Displacement for CNC Lathe With Pipe Frame Structure
Authors: Morimoto Yoshitaka , Suzuki Naohiko , Kaneko Yoshiyuki , Isobe Minoru 
Published: October 2013

A new CNC lathe with a pipe frame bed has been developed. One requested improvement for machine tools is their downsizing by minimizing the number of mechanical parts. Some researchers aim to construct a desktop factory. This trend has been attracting a lot of attention lately in the industrial field. When a machine tool bed is designed using castings and/or welded steel plate structures to comply with this request, it is difficult to ensure space for chip evacuation because of the space limitations of solid body components. This led us to develop another type of structure for machine tools.
A pipe frame bed has the ability to solve this problem. As represented by bridge trusses and flexible space structures, truss structures are traditional and fundamental in their design. This structure is expected to have enough space between the truss bars to solve the space problem. However, rigidity is the most significant issue for machine tools. Therefore, the desired rigidity is ensured by the use of diagonal braces.
Based on this design concept, a CNC lathe whose frame consists of pipes, joints, and diagonal braces has been developed with enough rigidity and space utility for chip evacuation. From the viewpoint of machine tool usage, the rigidity and stable dynamic characteristics of the structure must be obtained. Then, real-time vibration control theory is applied to the relative displacement between the tool post and the spindle. Active vibration control is used to suppress specific relative vibration modes.
In this paper, the effects of vibration control are evaluated by comparing the relative vibratory motion between the tool post and the spindle. Over 50% suppression has been achieved by applying vibration control to the target vibration mode. Additionally, using this control, the machined profile has been improved, and the roundness and harmonic analysis of the workpiece showed over 30% improvement.
Hands-On Assessment During Computer Aided Engineering Education
Authors: Hallberg Peter , Ölvander Johan 
Published: October 2013

This contribution discusses aspects and benefits from involving physical representations when teaching engineering design and Computer Aided Engineering at Linköping University, Sweden.
The paper presents a syllabus for a comprehensive introductory CAD course. The course is populated by some 300 students on the Mechanical Engineering Master’s and Bachelor’s programs, as well as the Design and Product Development Master’s program. Assessment is made via a project where the students are assigned to model and optimize a small catapult. The catapult is then produced, using cheap materials, by the hands of the students who modeled it. Finally, the catapult is validated by entering a contest, where it is judged in respect of accuracy, weight, and cost. The catapult assignment is constructed in such a way that the students are forced to seek individual ways of applying their newly acquired knowledge of the CAD tool. Some 100 catapults are produced but the material cost for each catapult is only about €4.
The low-cost nature of the catapults originates from research conducted at the Division of Machine Design at Linköping University, where the concept of Low-Cost-Demonstrators for enhancement of the conceptual design phase has been developed over the past decade. The results from this research point towards several benefits from using physical representations alongside the common digital tools during the early stages of the product development process. Furthermore, evaluation of parameters such as the students’ performance and their own opinions of the course show notable enhancement compared to previous courses.
Methodology for the Economic Viability of Companies in the Semantic Adaptation of Information Systems
Authors: Marcelino-Jesus Elsa , Sarraipa Joao , Antão Mário , Jardim-Goncalves Ricardo , Mendonça da Silva João 
Published: October 2013

In the current globalized and competitive business world it has become increasingly more important that companies adapt their knowledge bases, in order to establish more dynamic business partnerships. However, one of the main problems found in the establishment of such partnerships has to do with the lack of interoperability between technologic systems, especially those related to the semantic of shared knowledge. The integration and sharing of the knowledge representation elements of companies, performs a key role in the research challenges in the business interoperability area.
The paper presents a methodology to analyse the economic viability of companies in the needed effort to the conception of a common knowledge base in their operational domain area, in order to stimulate interoperability in the business cooperation. These studies also have as objective to support the development of the thesis that argues that in the future, the capability to adapt the semantics of business information systems will promote collaboration between companies, providing them new business opportunities.
Aeroderivative Power Generation With Coke Oven Gas
Authors: Dicampli James , Madrigal Luis , Pastecki Patrick , Schornick Joe 
Published: October 2013

A major environmental concern associated with integrated steel mills is the pollution produced in the manufacture of coke, an essential intermediate product in the reduction of iron ore in a blast furnace. Coke is produced by driving off the volatile constituents of the coal—including water, coke oven gas, and coal-tar—by baking the coal in an airless furnace at temperatures as high as 2,000 degrees Celsius. This fuses together the fixed carbon and residual ash. The coke oven gas (COG) byproduct, a combustible hydrogen and hydrocarbon gas mix, may be flared, recycled to heat the coal, or cleaned to be used as a fuel source to generate energy or used to produce methanol.
There are several inherent problems with COG as a fuel for power generation, notably contaminants that would not be found in pipeline natural gas or distillate fuels. Tar, a by-product of burning coal, is plentiful in COG and can be detrimental to gas turbine hot gas path components. Particulates, in the form of dust particles, are another nuisance contaminant that can shorten the life of the gas turbine’s hot section via erosion and plugging of internal cooling holes.
China, the world’s largest steel producing country, has approximately 1,000 coke plants producing 200MT/year of COG. GE Energy has entered into the low British thermal unit (BTU) gases segment in China with an order from Henan Liyuan Coking Co., Ltd. The gas turbines will burn 100% coke oven gas, which will help the Liyuan Coking Plant reduce emissions and convert low BTU gas to power efficiently. This paper will detail the technical challenges and solutions for utilization of COG in an aeroderivative gas turbine, including operational experience. Additionally, it will evaluate the economic returns of gas turbine compared to steam turbine power generation or methanol production.
3D Ultrasound Elastographic Imaging and Characterization of Breast Cancer In Vivo
Authors: Sayed Ahmed , Layne Ginger , Abraham Jame , Mukdadi Osama 
Published: October 2013

Breast cancer has a high mortality rate and caused about 13.7% of all cancer types deaths in women. Mammography imaging, having a good sensitivity to cancer, is used along with biopsy in a routinely manner, to differentiate between malignant and benign masses. Biopsy is an invasive procedure, and to reduce the necessity for performing it, ultrasound elastography was proposed. Elastography is a potential imaging technique to characterize breast masses, and to differentiate malignant from benign lesions, based on imaging estimated tissue strains under compression. This can result in lowering the number of unnecessary biopsies.
Using 3D elastography, lesion relative stiffness with the surrounding soft tissue is estimated at different compression levels, and used as a classification parameter to judge the malignancy of the lesion. In addition, elastography provided a means of emphasizing the strain difference of the lesion from the surrounding soft tissue, which can be used as an additional classification parameter. A pilot study on volunteered patients was performed, and results were compared with biopsy diagnosis as a reference. Initial elastography results showed good agreement with biopsy outcomes. Moreover, we constructed different strain elastograms including first principal, maximum shear and von Mises strains. Those new types of elastographic volumes incorporated the normal axial and shear strains together, which provided better distinction of the hard lesion from the soft tissue. In summary, the proposed elastographic techniques can be used as a noninvasive quantitative characterization tool for breast cancer, with the capability of visualizing and separating the masses in three dimensional space.
Using Hybrid and Problem-Based Learning Techniques to Enhance Teaching Effectiveness in a Large Feedback Controls Lecture Course
Authors: Parker Johné M. , Polston J. Daniel 
Published: October 2013

Enrollments in Mechanical Engineering programs continue to increase. Unfortunately, increases in faculty size have not kept pace at many universities, resulting in large course enrollments in even junior- and senior-level major courses. The primary goals of this study were to increase (or at least maintain) the quality of instruction, and increase student competency and understanding in a large lecture course having the same instructional personnel resources as a course with 60% of the enrollment. Hybrid and problem-based learning techniques, along with two optional weekly recitation sessions and an online discussion forum were incorporated into the course to meet these goals.
The course, a classical controls course, is one in which course concepts are generally considered to be a bit abstract to a considerable percentage of the class. The instructor had previously taught the course several times, so a well-paced course schedule and solid foundation of course notes were already in place. Student evaluation instruments in previous offerings included weekly homework, bi-weekly short quizzes, two exams and the final exam.
For the large lecture course (with an enrollment of 84 students), the evaluation instruments (homework, quizzes and exams) remained the same; however, the students formed self-selected triad teams. Approximately two-thirds of the quizzes, one-half of the homework and sixty percent of the final exam questions were assigned to the triad teams (the balance and both mid-term exams were individual submissions). The primary advantages of group quizzes and assignments were multi-fold: they facilitated group learning and peer-teaching to reinforce course concepts and allowed the instructor and teaching assistant to give the type of detailed feedback on submissions that would have been difficult or impossible to give on 84 individual submissions.
Course notes (including short Echo360 modules), handouts and homework and quiz solutions were maintained on an online course management system (i.e., Blackboard); additionally, the use of an online threaded discussion forum, Piazza, allowed students to post/answer questions (anonymously, if desired) and follow discussions about course content.
Team-based learning techniques were heavily used in latter course topics; the assigned readings, along with online course notes were used to prepare the students for the individual readiness assessment tests (RATs). Students discussed their answers on the RAT instruments in their triad groups (another opportunity for peer teaching) and disclosed group answers (which generally reflected a much higher level of understanding) to the entire class.
Student assessment of course techniques and a comparison of traditional (lecture-based) and hybrid-/problem-based techniques will be used to assess the efficacy of the problem-based approach and to suggest improvements for future offerings.