bluuebunny/crossref_metadata_2025 huggingface dataset:
Developed to be Unique
Authors: Bank William A.
Published: July 2018

This article focuses on that fact that the part of developing a successful product requires an understanding of what features in the product concept may be proprietary. Once understood, the proprietary features may be purposefully designed into or emphasized in the commercialized product. Successful product development basically involves research related to a product and potential markets, analysis of the research, and planning based on the research analysis. Research respecting the proprietary features of a product concept derives from or focuses on information regarding what can be protected in a product. Whether or not a product meets all the appropriate design criteria, driving product development with IP intelligence to emphasize features that can command market exclusivity and high demand will help ensure its success. IP intelligence also can reveal opportunities in applications and fields that may not have been considered. Successful product development is IP and market-driven.
From Simple Rules, Complex Behavior
Authors: Brown Alan S.
Published: July 2018

This article focuses on creation of autonomous robots by engineers that can interact with the world around them by layering simple behaviors. The growing presence of autonomous robots at Hanover echoes the interest seen worldwide. In the United States, for instance, autonomous robots range in sophistication from simple Roomba household vacuum cleaners to the complex vehicles that competed in Defense Advanced Research Projects Agency’s Urban Challenge. Instead, engineers are looking for clues in the behavior of social insects. Ants have attracted the most interest. While an individual ant has only a limited range of simple behaviors, the way it interacts with other ants produces responses that make the nest appear intelligent. Autonomous robots need better localization and mapping. They must learn faster and more efficiently. They should work together better as a team. They need to be more robust. Above all, they need to get smarter. An ant works randomly because it has no choice. It stumbles around until it creates the shortest path to food. Humans can see the whole picture and pick out that path immediately.
Nuclear’s Model T
Authors: Smith Craig F.
Published: July 2018

This article discusses that the future of nuclear energy could lie in plants that can be factory built, shipped to a site, and operated 30 years without refueling. The scope and timing •of the “nuclear renaissance,” however, remain somewhat uncertain. All that is known is that in countries around the globe, including the United States, significant numbers of new nuclear energy projects are under way or in various stages of planning, and this activity represents a departure from that of recent decades. The broad interest in developing new small reactor system concepts seems to be in conflict with the trend toward ever-larger central station power plants, which is driven by the principle of economy of scale. The Secure Transportable Autonomous Reactor (STAR) concept and the Small Secure Transportable Autonomous Reactor (SSTAR) reactor in particular provide good examples of additional design features that could make the introduction of such reactors more readily accepted while offering the potential for economic performance that makes sense in comparison to other alternative sources of energy.
The Right Mix
Authors: Heijmans Ad
Published: July 2018

This review explores the use of computation fluid dynamics (CFD) tools embedded in its computer-aided design (CAD) software to create a right mix of gas and air for a wide range of applications. The new tools provide the ability to evaluate the performance of many potential alternatives in the initial stages of the design process. Early stage analysis makes it possible to improve the performance of the product and resolve design problems quickly and before large sums have been spent on a design that must be changed. The review also discusses that several best practices can help ensure the accuracy of CFD gas and air mixing simulation. The utilization of native 3D data places a premium on the quality of the solid model. The newest generation of CFD software contains sophisticated automatic control functions that make it possible to converge to a solution in almost every application without the need for manual tuning. CFD simulation in the preliminary stages in the design of products involving gas mixing can save time and money. Best practices tuned for the requirements of a particular industry can help design engineers avoid analysis mistakes.
Finding Forces
Authors: Thilmany Jean
Published: July 2018

This article explains how today's analysis software are helping engineers to quickly solve for more than one physical phenomenon at a time. Today's simulation software mirror real-life behavior. Engineers can now run multiple analyses within the same application or within loosely coupled applications. Other systems allow users to solve for more than one force at the same time. The capability to solve in tandem or to work with integrated systems greatly speeds the analysis process. Analysis advances also allow engineering firms to call upon the analysis software to design complex and never-before-seen products, to test for safety quicker than before, and to cut costs by perfecting designs earlier in the development process.
Floating Wind Turbines
Authors: Roddier Dominique , Weinstein Joshua
Published: July 2018

This article discusses the functioning of floating wind turbines. The engineering requirements for the design of floating offshore wind turbines are extensive. Wind turbine design tools usually consist of an aerodynamic model (for flow around the blades) coupled with a structural code. Aero-elastic models used in the design of fixed turbines calculate all the necessary loading parameters, from turbine thrust and power generation, to blade and tower deflections. The design of floating structures usually involves hydrodynamics tools such as WAMIT Inc.’s software for studying wave interactions with vessels and platforms, or Principia’s DIODORE, to predict the hydrodynamic quantities, such as added mass, damping and wave exciting forces, which are used as a kernel in the time domain simulations. In marine projects, design tools typically need to be validated against model tests in a wave tank or basin. Such work is performed frequently, and scaling laws are very well defined.
Keeping Secrets
Authors: Staley Daniel
Published: July 2018

This article explains how companies can handle confidential information properly to reduce leaks to competitors. Once a company identifies what information is or contains a trade secret, it is beneficial to list all trade secrets and sensitive material in a central register or secure computer database. Classifying trade secrets can also help determine how valuable a particular trade secret is to the company. Companies can restrict disclosure of trade secrets to key employees with a “need to know.” They can also require key employees to sign individual secrecy and noncompete agreements, making them personally liable for unauthorized disclosures. If possible, the agreement should be executed before hiring the employee. For those already on the payroll, the agreement should include a statement that the trade secret restrictions are being applied as part of a standard policy applicable to all employees. Companies also need to do their housekeeping. They need a regularly scheduled review of the trade secret portfolio to remove items that should no longer be considered trade secrets and perhaps to reclassify others.
Avoiding the Blowout
Authors: Borchardt John K.
Published: July 2018

This article elaborates the steps that a driller can take to keep oil and gas secure in a deep seawell. The first step is to use drilling fluid to create hydrostatic pressure in the wellbore to prevent oil and gas from surging up the well. Later, when the well is completed, the wellbore is usually filled with a completion fluid also designed to have a density sufficient to prevent escape of oil and gas from the rock formation. Drilling and completion fluids must be designed in such a way that they do not create excessive hydrostatic pressure. Too much pressure will incur waste because large volumes of the fluids will leak into the rock formations penetrated by the wellbore, where they cannot be retrieved. The next step of preparation is to pump a cement slurry containing various additives through the casing. Once hardened, the cement seals off the oil- and gas-bearing rock from the wellbore until the oil company is ready to produce the well.
Compelled to be Green
Authors: Winters Jeffrey
Published: July 2018

This article discusses comments and feedbacks received from the respondents of the ASME’s Sustainable Design Trend Watch Survey. The ASME/Autodesk study on sustainability was a comprehensive two-part survey gauging the opinions of members of ASME on matters of general sustainability and sustainable technologies. Part I included 10 aided questions, where respondents were asked to select from a list of answers. This survey was e-mailed to members of ASME. Part II included four aided questions and was mailed only to student members. Despite the challenging economy, respondents of the study indicate with a 6% increase over last year that they believe sustainable design will be further incorporated into their work in the year 2010. In addition to the survey questions, the respondents were given an opportunity to comment on the sustainability process in manufacturing, and many of those comments revealed a deep ambivalence toward the very idea of ‘sustainable manufacturing.’ A majority of engineers surveyed expected that no matter what, the companies they work for would have an increasingly large involvement with green or sustainable design specifications over the coming years.
Case of Misplaced Technology
Authors: Teska Kirk
Published: July 2018

This article demonstrates through several examples of misplaced technology and clash between intellectual property laws and freedom of speech. The first example stated in the article is that of an Apple engineer leaving his prototype next-generation iPhone in a bar and it ended up at gizmodo.com—a website devoted to technology. The folks at Gizmodo tore into the iPhone, confirmed its authenticity, and then put photographs of the phone along with a list of its new features on the gizmodo.com site. Apple, rather than suing, at least so far, simply asked for the prototype phone back and Gizmodo complied. Could Apple sue Gizmodo or would First Amendment protect Gizmodo, only depending upon certain different factors and to an extent on the particular court hearing the case. The ultimate authority on the First Amendment, the United States Supreme Court, generally loathes limiting free speech for any reason.
the mechanics of healing
Authors: Wiznia Daniel
Published: July 2018

This chapter discusses research and engineering programs undertaken to study knees and machines to help ligament-graft patients get on their feet. At the Hospital for Special Surgery in New York, researchers are investigating the biological mechanisms of how tendon heals to bone to ultimately influence rehabilitative protocols for the anterior fibula. The lab has been focusing on how mechanical loads placed on tendons affect the healing process by initiating biological signals. The current model involves studying rodents that have undergone anterior cruciate ligament (ACL) reconstruction to examine the effect of mechanical loading on tendon biology. The team will develop empirical evidence that is expected to lead to future protocols for therapy—in short, to have people heal and return to their normal lives.. One therapy that has demonstrated some success in patients recovering from ACL surgery has been continuous passive motion (CPM). The clinical CPM design has been rendered in Solidworks. The lab built a device and is now testing it on cadaver rats before moving on to live subjects.
Growth of Opportunity
Authors: Thornton Jack
Published: July 2018

This chapter focuses on growing opportunities for engineers starting early in the professional field. The convergence of Baby Boomer demographics, rising demand for electricity, and the state of America’s electricity infrastructure are shaping up to create a major job market in the United States for early-career engineers. The convergence points to a need by the power industry to hire thousands of new engineers by 2030. Large investment numbers are cited for the nation’s transmission and distribution grid that links generators, motors, computers, light bulbs, and everything in between. The chapter also discusses various challenges such as high percentage of industry workers reaching retirement eligibility. Coupled with those retirement concerns is the industry-wide expectation that electricity demand nationally is expected to grow in spite of the economic slowdown. The power companies’ observations reveal different approaches to their engineering workforces. Some lean toward new engineering school graduates. One reason for the expectation of growth in the transmission and distribution businesses is the ongoing development of smart grid technology, which will permit embedded metering, automatic load redistribution, and ultimately time-of-day pricing.
Patent Trolls
Authors: Teska Kirk
Published: July 2018

This article elaborates the practice of patent trolls. The maligned patent trolls have never been clearly defined and thus can be difficult to handle. The earliest trolls were first called “submariners.” The typical profile was someone who had numerous patent filings for futuristic ideas (futuristic at the time, anyway), who did not actually manufacture or sell anything, and who purposefully delayed letting the patents issue (often for twenty years or more) until the marketplace had fully embraced the technology mentioned in the patent filings. Then these submariners surfaced, allowed their patents to issue, and sued or threatened to sue many of the businesses in an entire industry often seeking a small percentage of a large company’s entire yearly revenue. A change in the patent laws put an end to these submariners: patents, beginning in 1995, now have a life of 20 years from the date of the application (instead of 17 years from issuance of the patent), meaning the submarining tactic of keeping a patent application pending eats up the life of any resulting patent.
Improving Survivability of Aircraft from Uncontained Gas Turbine Engine Failures
Authors: Adams Chris , Manion John
Published: July 2018

This article describes new measures to improve survivability of aircraft from uncontained gas turbine engine failures. The US military has adopted a common tool—Uncontained Engine Debris Damage Assessment Model (UEDDAM)—for its methodology to consider uncontained events in a more realistic manner. UEDDAM can handle the analysis for the release of the primary rotor-disk segment plus smaller engine debris fragments in directions out of the plane of rotation. The UEDDAM code requires an input of a three-dimensional geometric description of aircraft component positions within the aircraft and thus, in relationship to each other. The description uses a specific input format. Adopting an assessment methodology, like UEDDAM, results in a universal standard and uniformity of debris hazard evaluation across the involved agencies. Maintaining the 3D aircraft geometry model and its components/system functional flow data generated by aircraft manufacturers during their initial hazard assessment would simplify later debris hazard reassessments required by maintenance, repair, or military-modification to a commercial aircraft.
Complexity and Consequence
Authors: Armen Harry , Flumerfelt Shannon , Halada Gary P. , Kahlen Franz-Josef
Published: July 2018

This article discusses different reasons of failure of engineering systems and how such failures can be avoided. It is human nature and economically attractive to discount the low-probability, high-severity consequences in the design and development of complex systems. Discounting or ignoring the effects of worst-case scenarios, however, can lead to a culture of complacency that heightens risks. Failure due to poor development can be traced to a lack of organizational commitment to systems thinking. An example of this is a lack of communications between designers and end users. System designed without the user in mind and without regard to human factors for safe operation and maintenance can have disastrous results. Overly complex user interfaces in both hardware and software systems are common points of failure. Failures due to a lack of training should not be considered the fault of the individual operator, but as a blunder in foresight by management. Improved training of end users has been shown to significantly reduce system failures and improve the integrity of systems.
Hiring the Newly Minted
Authors: Rorrer Ronald
Published: July 2018

This article discusses Ronald Rorrer’s views of hiring a newly graduate engineer. He recommends that when hiring a newly graduated engineer, one should contact senior design instructors for realistic references. He believes that the senior design sequence, as much as a college course, can reveal the relevant character of an individual with respect to the ability to work with others and to a future work ethic. In fact, there are limitations to the senior design instructor’s view of students. The instructor can fixate on the manufacture of the product, and ignore the overall process of design, working in a team, and finally the production of the design. The senior design instructor will often have a more accurate insight into the students as practical engineers than any other professor.
Heads Up, Ears Perked
Authors: Sledje Ron
Published: July 2018

This article gives tips for career advancement for engineering graduates who are seeking for jobs. Engineers should listen attentively to gather information about the state of the business that is basic and important. They should evaluate options by looking at the probability of success, cost versus benefit, risk versus reward, and other criteria that may be important to their boss. The various survival skills that every engineer needs to develop are: think on the next level, work hard and work smart, develop your business skills, keep your résumé current, always look for jobs, never stop developing yourself, always develop your network, and do not be naïve. Following these principles successfully allows you to feel secure in yourself, regardless of your company situation, and this is empowering when times get tough.
Divided Opinion
Authors: Christensen Adam , Friedman Peter
Published: July 2018

This article explores the need of a government regulation that will play a vital role in US long-term economic/environmental/energy stability strategy. It is also important to remember that at every stage of the rulemaking process, there are opportunities for the general public to voice opinions about the rule, and the agency is often required by law to consider each of these comments. The regulatory uncertainty is nearly as detrimental as the regulations themselves, and it is often counterproductive to the goal of improving the environment. Expert points out that the regulatory uncertainty is nearly as detrimental as the regulations themselves, and it is often counterproductive to the goal of improving the environment. The United States has abundant natural resources and the technical expertise to harness them. Now there is only a need to put in place policies that positively impact our energy picture and carefully consider policies that interfere with that goal.
Scada Security?
Authors: Thilmany Jean
Published: July 2018

This article focuses on the introduction of advance security checks to counter negative publicity of supervisory control and data acquisition (SCADA) systems. The SCADA security concerns have come to be seen as a big deal because the systems can be found within power plants, refineries, pipelines, water treatment plants, and the telecommunications industry, where hackers could do great damage that would affect the public. In light of SCADA security concerns, security researchers have stepped up efforts to find and to call attention to the systems’ vulnerabilities. As national attention has only recently turned to SCADA security, system users have few regulatory specifications by which they must abide. In 2006, the federal government charged the North American Electric Reliability Corp., or NERC, with defining and implementing standards for critical infrastructure protection within the industry. A number of pieces of legislation have been passed and proposed to address software security. The big one right now is the Cybersecurity Act of 2012, which has been introduced by Senator Joseph Lieberman of Connecticut.
The Gasoline Diesel
Authors: Ciatti Steve
Published: July 2018

This article evaluates engine efficiency as a step towards improving fuel economy and emissions performance. Diesel engines tend to be very efficient; however, they have an emissions problem. They require complex and expensive equipment to meet pollution mandates. Spark ignition gasoline engines, on the other hand, do a much better job with emissions, but they are inherently less efficient. Thus, the research team at Argonne National Laboratory has decided to look for ways to combine the best characteristics of both. This new system is more like traditional diesel combustion than spark ignition, but uses a gasoline-like fuel and an innovative approach to combustion to minimize emissions. Diesel engines tend to run lean, meaning there is more oxygen in the mix than fuel, which reduces in-cylinder average temperatures. Research shows that gasoline spark engines have fatal efficiency flaws but comply easily and relatively inexpensively with emission requirements. Diesels are more efficient, but carry a heavy penalty for emission compliance. Different research teams’ challenge is to ensure robust, reliable operation during transient operation. The new system’s torque profile is essentially the same as that of a conventional diesel, and it provides excellent performance in the powerband where most people drive.
The Last Island of Automation
Authors: Edwards Rhex A.
Published: July 2018

This article reviews the transformation and application of inspection and measurement (I&M) technology in the manufacturing industry. I&M offers a wealth of information needed in the development of new products. Cummins and Ford are among the pioneers in connecting I&M systems to the rest of their companies’ computerized decision support systems. Both companies are making wider use of I&M information and bringing factory floor and top-level decision-making closer together. Inspection, test, and measurement results are also vital to establishing the performance of the assembly tools and the capabilities of the processes. Lack of good I&M information can help weaken competitiveness and undermine strategies such as design for manufacturing and design for assembly. Timeliness is also crucial. Squirreling I&M data away in engineering silos perpetuates inspection and measurement as the last island of automation, the repository of information learned and lost.
Lifecycle Management
Authors: Thilmany Jean
Published: July 2018

This article discusses the application of product life-cycle management (PLM) concepts in all types of manufacturing industries. PLM can handle product complexity whether a company designs a few items with many parts or a number of products that need to be localized to many communities around the globe. Fashion-driven industries are using PLM systems in new, idiosyncratic ways, and that means that they cannot simply purchase and implement an existing system the way an engineering company can. In fashion, PLM is used to keep abreast of trends and consolidate designs and inspirations. A study shows that the retail and apparel industries aren’t nearly as focused on product development as engineering companies are. For engineers, PLM is a way to centralize and to focus on product development and innovation. In retail and apparel, PLM is used to manage the supply chain more than product development.
The Winning Interview
Authors: Freisen E.N.
Published: July 2018

This article provides an overview of various successful tips and considerations that could result in a winning interview for a mechanical engineer. A winning interview is one that allows you to find out if the position and potential employer are really right for you. It is also one that allows the potential employer to determine if you are the best candidate for the position, and if you will fit into the employer’s team, now and in the future. One of the self-diagnostic tools is called ‘SWOT Analysis,’ in which ‘SWOT’ stands for ‘strengths, weaknesses, opportunities, and threats.’ Strengths and weaknesses focus on you. Opportunities and threats are directed away from you toward the organization and the environment in which it operates. Opportunities and threats are both external and internal to the organization. Learning about them requires some intelligence gathering. Besides noting the opportunities that you foresee for the employer, you should develop a strategy for overcoming the threats. Being open and direct in your questioning and observations during the interview will show your level of confidence and the effort you have made.
Turning Trash into Treasure
Authors: Crawford Mark
Published: July 2018

This article describes various aspects of advanced waste-to-energy (WTE) technologies for converting trash into a clean and valuable resource. Renewed interest in WTE is largely driven by new technologies, improved economic models, energy trends, and policy changes. Gasification of municipal solid waste is gaining attention as new technological advances make this process more affordable. Gasification is the partial oxidation of the organic content in the municipal solid waste (MSW) feedstock to produce a synthesis gas, or syngas, rich in hydrogen and carbon monoxide. Covanta Energy, a major player in the waste-to-energy field, has developed and commercialized a gasification process for unprocessed, post-recycled MSW, in an air-based process requiring no other reactants or energy inputs. Another WTE approach is converting waste into solid recovered fuels—blends of non-recycled waste that are engineered into a fuel-pellet feedstock. This technology is especially suitable for plastics such as disposable diapers that are difficult to recycle, or those that decompose slowly in landfills.
The Robotic Moment
Authors: Brown Alan S.
Published: July 2018

This article explores the change that robotic machines bring in human culture. A study shows that some children are learning to confide in robots because they are safer than people. Experts believe that technology is seducing humans with the illusion of companionship that could be turned on and off at will, without any mutuality. Robots’ faces and especially their eyes show emotion, and their voices reflect rhythms and tones of human skin, mimicking an interested listener. Researchers believe that sociable robots and artificial intelligence software are changing human expectations. Today’s robots are not only smarter, but also are increasingly able to engage humans emotionally. As a result, humans have begun to think about their relationships with robots in new and often startling ways. Many people view robots as safer than people. A big percentage of people believe that the need for caretaker robots for the elderly is self-evident. These robotic technologies are seductive, because they promise taht we will always be heard and never be alone.
Looking Back 40 Years—The Reheat Gas Turbine Applied to Energy Storage
Authors: van der Linden Septimus
Published: July 2018

The article presents an overview of the compressed air energy storage gas turbines (CAES GT). The CAES GT works at low turbine inlet temperatures and is capable of fast start and loading 10 minutes to full load. It is characterized by high ramp rates up or down with minimum load as low as 10%, and flat heat rate for most of the load range. With exceptional low fuel input efficiency of 85%, the kW/hr equivalent Btu input to the compression cycle must be added, resulting in an overall efficiency of close to 55%, impressive versus a 300 MW GTCC plant that is required to load follow when integrating renewable energy source. The metamorphosis from that of a “peak shaving” unit to that of a grid support and renewable energy enabler is now complete. Advanced Reheat Gas Turbines such as the GT24/26 with higher operating temperatures offer further potential development for CAES.
Endoscopic Closure of Large Defects With a Novel Clipping Device and a 4S-Modified Roeder Slipknot
Authors: Ge Shuchen , Ai Liaoyuan , Erdman Arthur G. , Song Chengli
Published: July 2018

Endoscopic closure is an essential procedure in gastrointestinal (GI) surgery, but currently it is difficult to close large defects endoscopically because of the lack of an appropriate device. Previously, we developed an endoscopic clipping device that has multifiring function and is equipped with an independent clamp. The goal of this study is to provide a new closure method with this device and 4S-modified Roeder (4SMR) slipknot. The feasibility of the closure method is examined by deploying two clips during one insertion onto the 4SMR slipknot to close a 5 cm full-thickness linear defect of an ex vivo porcine stomach from the center. Mechanical strengths of clip-knot closure and the slipknot as regards to tensioning forces are also evaluated. Specifically, the mechanical strength of the 4SMR slipknot is verified by mean peak forces to failure, while the knot is tensioning by 2.5, 5, 7.5, and 10 N force (n = 20 for each group), respectively. Experimental results indicate the clip-slipknot closure can withstand a distracting force of 6.3 ± 5.6 N. Tensioning force has a great influence on the mechanical strength of slipknot, with the mean peak force (tensioning force) being 7.1± 6.5, 16.3 ± 9.3, 18.9 ± 10.4, and 24.2 ± 12.0 N, respectively. The proposed closure method can be used for large defects. Tensioning force higher than 5 N is suitable to ensure a stronger 4SMR slipknot.
Experimental Investigation of Self-Excited Combustion Instabilities in a Lean, Premixed, Gas Turbine Combustor at High Pressure
Authors: Buschhagen Timo , Gejji Rohan , Philo John , Tran Lucky , Enrique Portillo Bilbao J. , Slabaugh Carson D.
Published: July 2018

Self-excited combustion instabilities in a high pressure, single-element, lean, premixed, natural gas (NG) dump-combustor are investigated. The combustor is designed for optical access and instrumented with high frequency pressure transducers at multiple axial locations. A parametric survey of operating conditions including inlet air temperature and equivalence ratio has been performed, resulting in a wide range of pressure fluctuation amplitudes (p′) of the mean chamber pressure (pCH). Two representative cases, flames A and B with p′/pCH=23% and p′/pCH=12%, respectively, both presenting self-excited instabilities at the fundamental longitudinal (1L) mode of the combustion chamber, are discussed to study the coupling mechanism between flame-vortex interactions and the acoustic field in the chamber. 10 kHz OH*-chemiluminescence imaging was performed to obtain a map of the global heat release distribution. Phase conditioned and Rayleigh index analysis as well as dynamic mode decomposition (DMD) is performed to highlight the contrasting mechanisms that lead to the two distinct instability regimes. Flame interactions with shear layer vortex structures downstream of the backward-facing step of the combustion chamber are found to augment the instability magnitude. Flame A engages strongly in this coupling, whereas flame B is less affected and establishes a lower amplitude limit cycle.
Modeling Approach for a Hydrolysis Reactor for the Ammonia Production in Maritime Selective Catalytic Reduction Applications
Authors: Johe Katrin , Sattelmayer Thomas
Published: July 2018

The catalytic generation of ammonia from a liquid urea solution is a critical process determining the performance of selective catalytic reduction (SCR) systems. Solid deposits on the catalyst surface from the decomposition of urea have to be avoided, as this leads to reduced system performance or even failure. At present, reactor design is often empirical, which poses a risk for costly iterations due to insufficient system performance. The presented research project proposed a performance prediction and modeling approach for SCR hydrolysis reactors generating ammonia from urea. Different configurations of hydrolysis reactors were investigated experimentally. Ammonia concentration measurements provided information about parameters influencing the decomposition of urea and the system performance. The evaporation of urea between injection and interaction with the catalyst was identified as the critical process driving the susceptibility to deposit formation. The spray of urea solution was characterized in terms of velocity distribution by means of particle-image velocimetry. Results were compared with theoretical predictions and calculation options for processes in the reactor were determined. Numerical simulation was used as an additional design and optimization tool of the proposed model. The modeling approach is presented by a step-by-step method, which takes into account design constraints and operating conditions for hydrolysis reactors.
A Multistage Approach to the Selective Assembly of Components Without Dimensional Distribution Assumptions
Authors: Aderiani Abolfazl Rezaei , Wärmefjord Kristina , Söderberg Rikard
Published: July 2018

Selective assembly is a means of obtaining higher quality product assemblies by using relatively low-quality components. Components are selected and classified according to their dimensions and then assembled. Past research has often focused on components that have normal dimensional distributions to try to find assemblies with minimal variation and surplus parts. This paper presents a multistage approach to selective assembly for all distributions of components and with no surplus, thus offering less variation compared to similar approaches. The problem is divided into different stages and a genetic algorithm (GA) is used to find the best combination of groups of parts in each stage. This approach is applied to two available cases from the literature. The results show improvement of up to 20% in variation compared to past approaches.
Investigation of Street Lamp With Automatic Solar Tracking System
Authors: Lu Siyuan , Dai Rong , Zhang Guangru , Wang Quan
Published: July 2018

A street lamp with automatic solar tracking system can control the adjusting mechanism of azimuth and altitude so that the solar panel may adapt itself to the sunlight to improve the photoelectric conversion efficiency. In this work, we demonstrated the design of the adjusting mechanism of azimuth and altitude and verified the wind resistance. The method was realized by capturing the incident direction of sunlight using the photodiode array. The signal of the photodiode array can be processed by LM339N and then was sent to the single chip, which can deal with the signal to the motor of the adjusting mechanism of azimuth and the linear actuator of the adjusting mechanism of altitude, respectively. The hall sensors, embedded in the adjusting mechanism, are utilized to fulfill the feedback of the motion position to the single chip. These results clearly reveal the potential of the system in application.
Experimental Study on Tribological Properties of Graphite-MoS2 Coating on GCr15
Authors: Meng F. M. , Cui Z. T. , Cheng Z. T. , Han H. L.
Published: July 2018

The graphite-MoS2 coated on GCr15 bearing steel is prepared through air spraying and its tribological performances are investigated experimentally. Then its coefficient of friction (COF) and wear scar width (WSW) are investigated through the MFT-5000 multifunction tribometer and other test equipments. The experimental results show that the addition of the graphite can effectively decrease the COF and narrow the WSW of the MoS2. There exists a critical applied load for wearing out the surface with the graphite-MoS2 coating. Moreover, there exists an optimal rotational speed of 500 rpm to decrease the COF and WSW of the GCr15 steel.
Inverted Brayton Cycle With Exhaust Gas Condensation
Authors: Kennedy Ian , Chen Zhihang , Ceen Bob , Jones Simon , Copeland Colin D.
Published: July 2018

Approximately 30% of the energy from an internal combustion engine is rejected as heat in the exhaust gases. An inverted Brayton cycle (IBC) is one potential means of recovering some of this energy. When a fuel is burnt, water and CO2 are produced and expelled as part of the exhaust gases. In an IBC, in order to reduce compression work, the exhaust gases are cooled before compression up to ambient pressure. If coolant with a low enough temperature is available, it is possible to condense some of the water out of the exhaust gases, further reducing compressor work. In this study, the condensation of exhaust gas water is studied. The results show that the IBC installed in series on a turbocharged engine can produce an improvement of approximately 5% in brake-specific fuel consumption at the baseline conditions chosen and for a compressor inlet temperature of 310 K. The main factors that influence the work output are heat exchanger pressure drop, turbine expansion ratio, coolant temperature, and turbine inlet temperature. For conditions when condensation is possible, the water content of the exhaust gas has a significant influence on work output. The hydrogen to carbon ratio of the fuel has the most potential to vary the water content and hence the work generated by the system. Finally, a number of uses for the water generated have been presented such as to reduce the additional heat rejection required by the cycle. It can also potentially be used for engine water injection to reduce emissions.
Spray–Wall Interactions in a Small-Bore, Multicylinder Engine Operating With Reactivity-Controlled Compression Ignition
Authors: Wissink Martin L. , Curran Scott J. , Kavuri Chaitanya , Kokjohn Sage L.
Published: July 2018

Experimental work on reactivity-controlled compression ignition (RCCI) in a small-bore, multicylinder engine operating on premixed iso-octane, and direct-injected n-heptane has shown an unexpected combustion phasing advance at early injection timings, which has not been observed in large-bore engines operating under RCCI at similar conditions. In this work, computational fluid dynamics (CFD) simulations were performed to investigate whether spray–wall interactions could be responsible for this result. Comparison of the spray penetration, fuel film mass, and in-cylinder visualization of the spray from the CFD results to the experimentally measured combustion phasing and emissions provided compelling evidence of strong fuel impingement at injection timings earlier than −90 crank angle degrees (deg CA) after top dead center (aTDC), and transition from partial to full impingement between −65 and −90 deg CA aTDC. Based on this evidence, explanations for the combustion phasing advance at early injection timings are proposed along with potential verification experiments.
Design of a Wide-Range Centrifugal Compressor Stage for Supercritical CO2 Power Cycles
Authors: Pelton Robert , Jung Sewoong , Allison Tim , Smith Natalie
Published: July 2018

Supercritical carbon dioxide (sCO2) power cycles require high compressor efficiency at both the design point and over a wide operating range. Increasing the compressor efficiency and range helps maximize the power output of the cycle and allows operation over a broader range of transient and part-load operating conditions. For sCO2 cycles operating with compressor inlets near the critical point, large variations in fluid properties are possible with small changes in temperature or pressure. This leads to particular challenges for air-cooled cycles where compressor inlet temperature and associated fluid density are subject to daily and seasonal variations as well as transient events. Design and off-design operating requirements for a wide-range compressor impeller are presented where the impeller is implemented on an integrally geared compressor–expander concept for a high temperature sCO2 recompression cycle. In order to satisfy the range and efficiency requirements of the cycle, a novel compressor stage design incorporating a semi-open impeller concept with a passive recirculating casing treatment is presented that mitigates inducer stall and extends the low flow operating range. The stage design also incorporates splitter blades and a vaneless diffuser to maximize efficiency and operating range. These advanced impeller design features are enabled through the use of direct metal laser sintering (DMLS) manufacturing. The resulting design increases the range from 45% to 73% relative to a conventional closed impeller design while maintaining high design point efficiency.
Efficient Uncertainty Propagation for High-Fidelity Simulations With Large Parameter Spaces: Application to Stiffened Plate Buckling
Authors: Nahshon Ken , Reynolds Nicholas , Shields Michael D.
Published: July 2018

Uncertainty quantification (UQ) and propagation are critical to the computational assessment of structural components and systems. In this work, we discuss the practical challenges of implementing uncertainty quantification for high-dimensional computational structural investigations, specifically identifying four major challenges: (1) Computational cost; (2) Integration of engineering expertise; (3) Quantification of epistemic and model-form uncertainties; and (4) Need for V&V, standards, and automation. To address these challenges, we propose an approach that is straightforward for analysts to implement, mathematically rigorous, exploits analysts' subject matter expertise, and is readily automated. The proposed approach utilizes the Latinized partially stratified sampling (LPSS) method to conduct small sample Monte Carlo simulations. A simplified model is employed and analyst expertise is leveraged to cheaply investigate the best LPSS design for the structural model. Convergence results from the simplified model are then used to design an efficient LPSS-based uncertainty study for the high-fidelity computational model investigation. The methodology is carried out to investigate the buckling strength of a typical marine stiffened plate structure with material variability and geometric imperfections.
Multiphysics Modeling of Pressurized Water Reactor Fuel Performance
Authors: Zhu Wang , Chungyu Zhang , Cenxi Yuan
Published: July 2018

Nuclear fuel rods operate under complex radioactive, thermal, and mechanical conditions. Nowadays, fuel rod codes usually make great simplifications on analyzing the multiphysics behavior of fuel rods. The present study develops a three-dimensional (3D) module within the framework of a general-purpose finite element solver, i.e., abaqus, for modeling the major physics of the fuel rods. A typical fuel rod, subjected to stable operations and transient conditions, is modeled. The results show that the burnup levels have an important influence on the thermomechanical behavior of fuel rods. The swelling of fission products causes a dramatically increasing strain of pellets. The variation of the stress and the radial displacement of the cladding along the axial direction can be reasonably predicted. It is shown that a quick power ramp or a reactivity insertion accident can induce high tensile stress in the outer regime of the pellet and may cause further fragmentation to the pellets. Fission products migration effects and differential thermal expansion become more severe if there are flaws or imperfections on the pellet.
The Effect of Solvent on the Capacity Retention in a Germanium Anode for Lithium Ion Batteries
Authors: Mishra Kuber , Xu Wu , Engelhard Mark H. , Cao Ruiguo , Xiao Jie , Zhang Ji-Guang , Zhou Xiao-Dong
Published: July 2018

A thin and mechanically stable solid electrolyte interphase (SEI) is desirable for a stable cyclic performance in a lithium ion battery. For the electrodes that undergo a large volume expansion, such as Si, Ge, and Sn, the presence of a robust SEI layer can improve the capacity retention. In this work, the role of solvent choice on the electrochemical performance of Ge electrode is presented by a systematic comparison of the SEI layers in ethylene carbonate (EC)-based and fluoroethylene carbonate (FEC)-based electrolytes. The results show that the presence of FEC as a cosolvent in a binary or ternary solvent electrolyte results in an excellent capacity retention of ∼85% after 200 cycles at the current density of 500 mA g−1; while EC-based electrode suffers a rapid capacity degradation with a capacity retention of just 17% at the end of 200 cycles. Post analysis by an extensive use of X-ray photoelectron spectroscopy (XPS) was carried out, which showed that the presence of Li2O in FEC-based SEIs was the origin for the improved electrochemical performance.
Dynamic Analysis on Unbuckling Process of Helically Buckled Coiled Tubing While Milling Plugs
Authors: Qin Xing , Gao Deli , Liu Yongsheng
Published: July 2018

In down-hole interventions, the thin elastic coiled tubing (CT) extended for thousands of meters underground would typically undergo helical buckling as a result of axial compressive force. This paper builds an analytical model to describe the unbuckling behavior of a helically buckled CT with a new view to the stretching process in the plug milling operations. The new dynamic unbuckling equation is built on the basis of the general bending and twisting theory of rods. Under the continuous contact assumption, the helical angle is only subject to time; thus, the dynamic equations can be simplified and the analytical solutions can be obtained. By using the new governing equations, the angular velocity, axial force, and contact force relative to CT are analyzed in the unbuckling process. The calculation results indicate that the parameters including CT diameters and wellbore diameters have a strong influence on the variation of axial force and wellbore contact force. Moreover, the wellbore contact force is greater than zero during the whole unbuckling process which confirms the continuous contact assumption. These new results provide important guidance for accurate job design for the plug milling operations during the well completion stage.