bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulating the Effects of Initial Condition Variance in the Investment Casting Process
Authors: Sowden Ike , Currier George 
Published: November 2013

A consistent casting process can sometimes be a challenge to achieve due to the wide array of initial conditions that can affect the process. Variation in these initial conditions during the casting process can generate an array of unexpected results, which sometimes have a negative effect on the structural integrity of the castings. Cold shuts, shrinkage formation, and hot tears are just a few examples of the defects that can arise.
Throughout the history of the railroad, castings found with these types of defects have plagued the industry. Since castings are considered a leading method for manufacturing metal components, it is important to have a consistent and repeatable process. Without this, defects can drive the quality of the product down and cause castings to fail while in service. Studying the effects of initial condition variance can teach us which parameters can positively or negatively affect the overall casting process. Improvements in a foundry’s process can then be implemented resulting in a more consistent, reliable final product.
Computer simulation software has proven to assist in predicting defects before a single casting has even been poured. As with any simulation, care must be taken when setting up the input parameters. Without careful consideration of the initial conditions, the results may not reflect the actual process. Because of this fact, Strato, Inc. continues researching and sharing its findings regarding the effectiveness of these simulations. This research helps to ensure that a higher quality product with a lower fall-out rate is delivered promptly to the customer.
Specific initial conditions are explored in this paper. Variance in the soundness of the casting process is examined through the use of material density plots. These density plots, which provide a visual indication of internal shrinkage, have been obtained using simulation software. These predictions of shrinkage are then compared to actual castings that were poured using the same initial conditions. Results from the following three case studies present evidence to further the belief that using this software, which allows for a deeper understanding of the thermal and fluid dynamics of the casting process, has a direct impact on both quality, as well as the time it takes to develop a sound process. With the knowledge gained by simulating variance in initial casting conditions, a more robust rigging design and overall casting process can be achieved.
This paper is a continuation of Strato’s investigation into the effects of varying initial conditions with simulation software and comparison with real world results. The first part was presented at the 2012 ASME JRC and can be found within its proceedings. Although some concepts and terms are explained in both papers, it is suggested that part one of this paper be reviewed by those who would like more insight into the framework of this paper.
Detection of GNSS Horizontal Position Error Using 3D-Track Map
Authors: Jonas M. 
Published: November 2013

The increasing progress in the field of satellite navigation systems (GNSS, SBAS) in the recent decades supports effort to use it for determination of train position for railway safety-related systems. Satellite-based augmentation systems (SBAS) such as WAAS in the USA, and EGNOS in Europe, are available and a new global satellite navigation system Galileo is being built by the European GNSS agency (GSA). The currently available SBAS systems were developed in order to satisfy aviation requirements. But the safety concept on railways is very different from the aviation safety concept. The railway safety concept in Europe is determined by means of the CENELEC standards (EN 50126, EN 50129, EN IEC 61508). So it is necessary to find a way how to use GNSS systems in accordance with strict railway standards. The main problem is attainment of sufficient integrity of position solution [5, 12]. Satisfaction of safety integrity level 4 (SIL4) is necessary for railways [6, 7, 8, 9]. At the beginning, it can provide low-cost controlling system for the local, regional and freight railway lines. GNSS provides a 3D position (position in horizontal and vertical plane). The value of altitude is cruical for application in aviation, in ground transportation this value is not so important. On the contrary, the value of horizontal position is cruical. For the purpose of increasing the integrity of GNSS-based position determination we propose a new method of the detection of a GNSS horizontal position error based on the relation between vertical and horizontal position error. As was mentioned for example in [4], as GPS is a three dimensional positioning system, errors between any two coordinates may be correlated, and so there can be relations between errors in individual dimensions. The general 3D GPS-based position solution can be divided into two parts:
- 2D horizontal position
- 1D vertical position
We investigated the relation between errors in the horizontal and vertical plane in real data measured by a GNSS receiver. It was static measurement and the antenna location was exactly known. The vertical position provided by GNSS is not constant. In ground transportation we can mostly make an assumption of nearly a constant value of altitude during the ride. Especially in railway transportation the changing of altitude during the ride is limited by many factors (railway standards, properties of track) So we investigate the possibility of using values of altitude to estimate a position error in the horizontal plane. As the receiver determines the values of the vertical position in real time, the detection of the horizontal position error based on the values of altitude can help detect the actual position error in horizontal plane during the train ride also in real time. The sensitivity of this method to errors in pseudoranges (error caused by multipath) was also investigated. This was done by simulation with software receiver Pegasus (Eurocontrol). The analysis was based on real data from GNSS.
Performance Evaluation of Hybrid Technology Networking for Real-Time Monitoring in Freight Railroad Operations
Authors: Shrestha Pradhumna Lal , Hempel Michael , Rakshit Sushanta , Sharif Hamid , Punwani John , Stewart Monique 
Published: November 2013

Traditional Wireless Sensor Network (WSN) solutions have been deemed insufficient to address the requirements of freight railroad companies to implement real-time monitoring and control of their trains, tracks and wayside equipment. With only ZigBee-based elements, the transmission capabilities of WSN devices are limited in terms of coverage range and throughput. This leads to severe delay and congestion in the network, particularly in railroad scenarios that usually require the nodes to be arranged in linear chain-like topology. In such a multi-hop topology to communicate from one end of a train to the locomotive — and due to ZigBee’s limited communication range — data needs to be transmitted using a very high number of hops and thus generates long delays and congestion problems.
To overcome this drawback, we have proposed a heterogeneous multi-hop networking approach called “Hybrid Technology Networking” (HTN). In HTN we combined Wireless Local Area Network (WLAN) technologies like WiFi, which provide improved communication range and higher data rates, with low-power communication technologies like ZigBee. This significantly reduces the number of hops required to deliver data across the network and hence solves the issues of delay and congestion, while also achieving superior enery efficiency and network lifetime. The sensor nodes are logically divided into clusters and each cluster has a WiFi “gateway”. All intra-cluster communication is achieved via IEEE 802.15.4 and ZigBee protocols, while all inter-cluster communication utilizes WiFi protocol standards.
To implement our proposed technology in railroad networks, we are designing hardware prototypes and simulation models to evaluate the functionality and performance of our HTN solution, which is designed around a dual network stack design governed by the HTN protocol. This ensures full compliance with IEEE and industry communication protocols for interoperability. Since no simulation tools that seamlessly combine both WSN and WLAN technologies in a single module exist, we wrote our own simulation environment using OPNET. In this paper, we have provided information of implementing the HTN protocol in OPNET and the simulation results for different scenarios relevant to railroad operations. These results will demonstrate the efficacy of our proposed system as well as provide the baseline data for testing the hardware devices in live networks. Under simulated traffic and channel conditions and device configurations, we observed a decrease of 77.27% in end-to-end delay and an increase of 69.70% in received data volume when using HTN compared to ZigBee-only multi-hop networks, simulated over 14 railcars in railroad-relevant scenarios.
Recommendations for the PRIIA Specifications on the Next Generation of Accessible Passenger Rail Cars
Authors: Hunter-Zaworski K. M. , Rutenberg Uwe , Shurland Melissa 
Published: November 2013

The recommendations for the new PRIIA specifications of the Next Generation of Accessible Passenger rail cars take access by people with disabilities to a new level of inclusion. The recommendations under consideration are more responsive to changes in population demographics and reflect the changes in wheeled mobility devices technologies. The new recommendations are evidence based on research, and the development process involves a broad cross section of the passenger rail industry as well as federal agencies responsible for accessibility.
The recommendations focus on making the next generation of passenger rail cars more inclusive and accessible. The recommendations incorporate changes in population demographics and wheeled mobility technologies and go above and beyond current Americans with Disabilities Act regulations that were written over twenty years ago. Specifically that the US population is getting older and more obese. In most US states between 20 and 30% of the population show a Body Mass Index (BMI) of 30. Some examples of the new recommendations include the following; the wheelchair lift minimum payload will be increased from 600 to 800 pounds, the lift platform will be extended in length from 30 × 48 to 30 × 54 inches, and the maneuvering and accessible seating location is increased to 32 inches wide by 59 inches long. A new recommendation for making the rail car vestibule more accessible for a 90 degree turn includes increasing the vestibule width from 42 to 44 inches. These recommendations will make passenger rail cars accessible to about 90 percent of the current users of wheeled mobility devices. Currently the passenger rail vehicles can only accommodate approximately 50 percent of wheeled mobility devices.
There are also provisions in the new recommendations for improving the accessible restroom and its components, even though some of the current passenger rail vehicles have reasonably accessible lavatories. The new recommendations include space for dependent and independent transfers in the restroom and will provide a more consistent level of accessibility for all the new passenger rail cars. Space is recommended for the accommodation of service animal in each car.
The new recommendations also include enhanced provisions for passengers who are deaf or hard of hearing. At a minimum the recommendations incorporate current technologies that are used in transit vehicles for dual mode communication, and also include suggestions for accessible real time passenger information and communication systems, and making information accessible on personal mobile media.
The new recommendations are in the validation and approval process. As a first step, the recommendations will be approved by the PRIIA Section 305 Next Generation Equipment Committee.
Viable Production of Diesel From Non-Recyclable Waste Plastics
Authors: Bordynuik John William 
Published: November 2013

The art of refining liquid hydrocarbons (crude oil) into diesel, gasoline, and fuel oils was commercially scaled decades ago. Unfortunately, refineries are technologically limited to accepting only a very narrow range of liquid hydrocarbons with very specific properties and minimal contaminates. Unrecyclable, hydrocarbon-based waste is a significant environmental problem increasing every year. According to the Environmental Protection Agency’s 2010 Facts and Figures report, over 92% of waste plastic is not recycled and with a growth rate of approximately 8% per year, there exists a critical need for a viable and environmentally sound, general purpose hydrocarbon-based recycling process. Hydrocarbon streams that fall outside of accepted refinery standards have traditionally been landfilled or melted into products of low value.
The barriers and challenges are so great that previous attempts to refine waste plastics into fuel resulted in unviable batch-based machines producing low-value, unstable mixed fuels. However, over the course of three years JBI, Inc. (“JBI”) has broken through these barriers and has designed and built a viable commercial-scale continuous refinery capable of processing a wide-range of hydrocarbon-based waste into ASTM specification fuels.
Research and testing of scale-up through 1-gallon, 3000 gallon, multi-kiln, and 40 ton/day processors took place in a plant in Niagara Falls, NY. Technical challenges encountered and lessons learned during process development will be explained in detail.
In 2009, our technology was “molecularly audited” by IsleChem, LLC (“IsleChem”) of Grand Island, NY and in 2012, the full-scale plant was viably validated by SAIC Energy, Environment & Infrastructure, LLC (“SAIC”). Numerous sources of waste plastic and users of the resulting fuel products conducted extensive audits of the technology, process, and plant. For the purpose of this paper, processing of waste plastics will be discussed in detail; however, this technology can be applied to other waste hydrocarbon-based materials such as contaminated monomers, waste oils, lubricants and other composite waste streams.
N-methyl-d-aspartate Receptor Antagonist Ketamine Impairs Action-monitoring Activity in the Prefrontal Cortex
Authors: Skoblenick Kevin , Everling Stefan 
Published: November 2013

Abstract
Failures in monitoring of self-generated actions are thought to underlie the positive symptoms in schizophrenia. It has been hypothesized that these deficits may be caused by a dysfunction of N-methyl-d-aspartate receptors (NMDARs). Here we recorded the activity of prefrontal neurons in monkeys performing an antisaccade task, while we administered a subanesthetic dose of the noncompetitive NMDAR antagonist ketamine. Many neurons discriminated between correct antisaccades and response errors in their postresponse activity. Ketamine increased the activity for the neurons' nonpreferred response, thereby decreasing the neurons' performance selectivity. Ketamine also affected the monkeys' behavior after an error, consistent with a deficit in error detection. The results show that NMDARs play an important role in action monitoring in primates. The decrease in performance selectivity of prefrontal neurons after ketamine can help to explain the deficits in action monitoring found in humans after ketamine administration and provides support for the hypothesis that an NMDAR dysfunction underlies self-monitoring deficits and psychotic symptoms in schizophrenia.
Potential Predictability of North American Surface Temperature. Part I: Information-Based versus Signal-To-Noise-Based Metrics
Authors: Tang Y. , Chen D. , Yan X. 
Published: November 2013

Abstract
In this study, the potential predictability of the North American (NA) surface air temperature was explored using information-based predictability framework and Ensemble-Based Predictions of Climate Changes and their Impacts (ENSEMBLES) multiple model ensembles. Emphasis was put on the comparison of predictability measured by information-based metrics and by the conventional signal-to-noise ratio (SNR)-based metrics. Furthermore, the potential predictability was optimally decomposed into different modes by maximizing the predictable information (equivalent to the maximum of SNR), from which the most predictable structure was extracted and analyzed.
It was found that the conventional SNR-based metrics underestimate the potential predictability, in particular in these areas where the predictable signals are relatively weak. The most predictable components of the NA surface air temperature can be characterized by the interannual variability mode and the long-term trend mode. The former is inherent to tropical Pacific sea surface temperature (SST) forcing such as El Niño–Southern Oscillation (ENSO), whereas the latter is closely associated with the global warming. The amplitude of the two modes has geographical variations in different seasons. On this basis, the possible physical mechanisms responsible for the predictable mode of interannual variability and its potential benefits to the improvement of seasonal climate prediction were discussed.
Approximate and Efficient Methods to Assess Error Fields in Spatial Gridding with Data Interpolating Variational Analysis (DIVA)
Authors: Beckers Jean-Marie , Barth Alexander , Troupin Charles , Alvera-Azcárate Aida 
Published: November 2013

Abstract
This paper presents new approximate methods to provide error fields for the spatial analysis tool Data Interpolating Variational Analysis (DIVA). The first method shows how to replace the costly analysis of a large number of covariance functions with a single analysis for quick error computations. Then another method is presented where the error is only calculated in a small number of locations, and from there the spatial error field itself is interpolated by the analysis tool. The efficiency of the methods is illustrated on simple schematic test cases and a real application in the Mediterranean Sea. These examples show that with these methods, one has the possibility for quick masking of regions void of sufficient data and the production of “exact” error fields at reasonable cost. The error-calculation methods can also be generalized for use with other analysis methods such as three-dimensional variational data assimilation (3DVAR) and are therefore potentially interesting for other implementations.
Simulations of Observed Lee Waves and Rotor Turbulence
Authors: Ágústsson Hálfdán , Ólafsson Haraldur 
Published: November 2013

Abstract
On 18 November 2008 a commercial aircraft encountered severe turbulence while flying in westerly flow along the southeastern coast of Iceland and descending from 2500 m down to the ground for a safe landing. Numerical simulations at horizontal resolutions of 9, 3, and 1 km are compared to the available observations. The simulations reproduce the situation, with an observed severe downslope windstorm at the ground as well as associated amplified lee waves and a rotor aloft, while climate data indicate that all observed westerly windstorms in the region are of the same type and occur in a similarly structured atmosphere. Strong shear turbulence is simulated at the interface of the lee wave and the rotor, as well as inside the rotor. The lee waves and the turbulence patterns are not stationary and as the upstream vertical wind shear increases, the lee wave becomes less steep, but the turbulence increases temporarily while the rotor circulation breaks down. From a forecasting perspective, this event could have been foreseen quite accurately, but not with the NWP tools that were in use for aviation forecasts, as their resolution was simply not adequate for resolving hazardous features of flow in and above complex terrain on the scale of this event. This event underlines the urgency of delivering products from finescale simulations over complex terrain to pilots and forecasters. Such products need to be developed taking into account the transient nature of the flows and the hazards.
Precursor Circulation Features for Persistent Extreme Precipitation in Central-Eastern China
Authors: Chen Yang , Zhai Panmao 
Published: November 2013

Abstract
Using a composite analysis, the typical precursor circulation configuration from the lower to the upper troposphere responsible for persistent extreme precipitation events (PEPEs) of double-blocking-high type in central-eastern China is identified. The potential of these precursors is further assessed based on the composites of normalized anomalies. The composite results reveal that at 500 hPa, about 2 weeks prior to the onset of PEPEs, a positive height anomaly progresses toward the Ural Mountains region from 30°E and another positive anomaly extends southwest from high latitudes toward the Sea of Okhotsk. Afterward, these two positive anomalies grow in magnitude in situ. The double blocking highs are finally well established with height anomalies of 2.4 and 1.8 standard deviations above normal, respectively. At 850 hPa, an anomalous anticyclone originating from the equatorial western Pacific migrates northwestward 1 week prior to the event occurrence, resulting in a greatly intensified moisture transport toward central-eastern China with a magnitude anomaly over four standard deviations above normal. In the upper troposphere, the eastward-extended South Asia high and the southward-displaced westerlies combine to provide favorable upper-level divergence for PEPEs.
These composites of the anomalies and normalized anomalies may offer forecasters some useful clues in recognizing significant weather events about 1–2 weeks in advance of an event.
Ultrasound-guided lumbar puncture as a diagnostic aid to reduce number of attempts and complication rates
Authors: Honarbakhsh Shohreh , Osman Chinar , Teo James TH , Gabriel Carolyn 
Published: November 2013

Ultrasound-guided lumbar puncture (LP) could be beneficial in situations where anatomical landmarks are difficult to identify. There is some evidence that it is associated with increased success rates and procedural ease. Its effect on complication rates has not been explored. This mixed retrospective-prospective case-control study over 6 months compares unguided (retrospective data, n = 28) and ultrasound-guided LPs (prospective data, n = 23) in non-emergency patients. Presence of factors making LPs difficult (DF) i.e. BMI ≥30 kg/m2, scoliosis and previous lumbar spinal surgery were recorded. There was a significant difference in attempt rates between unguided and ultrasound-guided LPs (median 2 vs. 1; p = 0.01) with complication rates of 50% and 26.1%, respectively ( p = 0.15). In a subgroup analysis, complication rates were significantly different in those with DF (76.9%, unguided LPs (n = 13) vs. 33.3%, ultrasound-guided LPs (n = 12); p = 0.03), with an absolute risk reduction of complications of 43.6% (NNT of 2.3) in ultrasound-guided vs. unguided LPs. In those with DF, the back pain rates were significantly reduced (53.8% unguided LPs vs. 8.3% ultrasound-guided LPs; p = 0.02). In the ultrasound-guided LP group, there was no blood contaminated cerebrospinal fluid samples, whereas this occurred in 14% of unguided LPs. Ultrasound-guidance significantly reduced the number of LP attempts. In those with DF, the use of ultrasound significantly reduced post-procedural complication, particularly back pain. Ultrasound-guidance during LP procedures can reduce patient discomfort and encourage patient safety, thereby improving clinical practice.