bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuel Tank Integrity Research: Fuel Tank Analyses and Test Plans
Authors: Jacobsen Karina , Llana Patricia , Carolan Michael , Sullivan Laura
Published: November 2013

The Federal Railroad Administration’s Office of Research and Development is conducting research into fuel tank crashworthiness. Fuel tank research is being performed to determine strategies for increasing the fuel tank impact resistance to mitigate the threat of a post-collision or post-derailment fire. In accidents, fuel tanks are subjected to dynamic loading, often including a blunt or raking impact from various components of the rolling stock or trackbed. Current design practice requires that fuel tanks have minimum properties adequate to sustain a prescribed set of static load conditions. Current research is intended to increase understanding of the impact response of fuel tanks under dynamic loading. Utilizing an approach that has been effective in increasing the structural crashworthiness of railcars, improved strategies can be developed that will address the types of loading conditions which have been observed to occur in a collision or derailment event.

U.S. rail accident surveys reveal the types of threats fuel tanks are exposed to during collision, derailments and other events. These include both blunt impacts and raking impacts to any exposed side of the tank. This research focuses on evaluating dynamic impact conditions for fuel tanks and investigating how fuel tank design features affect the collision performance of the tank. Research activities will include analytical modeling of fuel tanks under dynamic loading conditions, dynamic impact testing of fuel tank articles, and recommendations for improved fuel tank protection strategies.

This paper describes detailed finite element analyses that have been developed to estimate the behavior of three different fuel tanks under a blunt impact. These analyses are being used to understand the deformation behavior of different tanks and prepare for planned testing of two of these tanks. Observations are made on the influence of stiffeners, baffles, and other design details relative to the distance from impact.

This paper subsequently describes the preliminary test plans for the first set of tests on conventional passenger locomotive fuel tanks. The first set of tests is designed to measure the deformation behavior of the fuel tanks with a blunt impact of the bottom face of the tanks. The test articles are fuel tanks from two retired EMD F-40 locomotives. A blunt impact will be conducted by securing the test articles to a crash wall and impacting them with an indenter extending from a test cart. This set of tests is targeted for late summer 2013 at the Transportation Technology Center (TTC) in Pueblo, Colorado.

Both blunt and raking impact conditions will be evaluated in future research. Tests are also being planned for DMU fuel tanks under dynamic loads.
Integrated Traffic Signal Control Along Corridors With Multiple Intersections Near Highway-Rail Grade Crossings
Authors: Chen Yifeng , Rilett Laurence R.
Published: November 2013

Traffic signal optimization for traffic signals located near highway-rail grade crossings (HRGC) can be difficult because of the complex nature of the interactions between the two systems and the necessity of considering multiple objectives, such as safety and operational efficiency. The problems are magnified when considering traffic control for corridors that have multiple intersections located near HRGCs.

This paper develops a methodology for optimizing traffic signals along a highway-railway corridor while considering the dual objectives of maximizing safety and efficiency. The Highway 6 (Cornhusker Hwy) corridor in Lincoln, Nebraska was used as a test bed. The corridor was modeled in VISSIM, and was used to emulate the traffic control along Highway 6, including the preemption logic. The traffic control logic was modeled using the Vehicle Actuated Programming (VAP) in the VISSIM simulation model. In addition, the logic allows multiple train events on the railway track that runs parallel to Highway 6 to be modeled. The model was calibrated to local traffic conditions using empirical field data. The impact of train frequency, length, direction, speed, etc., on the performance of the network and pedestrian safety will be evaluated.
Analysis of End Hose Elasticity
Authors: Hoefler Michael , Bonacum Brian , Hua Lin
Published: November 2013

This paper investigates the relationship between end hose elasticity and the potential amount of energy coupled railroad cars can absorb in charged condition before pull a part force separation occurs.

One of the most significant issues with the existing end hose is that it will uncouple after enough force is applied causing a loss of pressure in the brake system. Our initiative to evolve the end hose into a more durable wire braided rubber material from the standard hand wrapped construction has decreased this potential for separation in the field.

Simulation testing using end hoses from three manufacturers is studied and compared. Charged hose assemblies were coupled and pulled apart. The results showed one end hose stretched nearly double the distance of the other hoses. Analysis of the resulting data will show that a more elastic hose will allow a train brake system to absorb more energy thus reducing the opportunity for a disconnect while in service.
Aluminum/Stainless Steel Conductor Technology: A Case for its Adoption in the US
Authors: Forman K. G.
Published: November 2013

Numerous technologies exist for providing electrical power to transit systems. Where overhead space is costly or where overhead structures may be deemed obtrusive, 3rd rail is a reliable and cost-effective way to provide considerable power to transit vehicles. Since the early years of railway electrification, 3rd rail conductors have evolved from steel to aluminum/steel composite to aluminum/stainless steel compositions. Aluminum stainless steel conductors are currently used in approximately 40% of the over 10,000km of 3rd rail systems worldwide. Adoption of this technology in the United States, however, stands at less than 5%.

This paper examines aluminum/stainless steel 3rd rail technology from technical and economic perspectives. The author makes a case for its adoption in new and existing 3rd rail systems in the United States.
Developing a Reliable Method for Signal Wire Attachment Without Martensite
Authors: Workman David , Levesque Stephen , Vaze Suhas
Published: November 2013

Railroad signaling systems are a vital part of the national railroad that detect trains on the track, identify track fractures, prevent derailments, and alert signal crossing stations when a train approaches. Failures in the signal wire attachments (studs) to rail create uncertainty in the system resulting in reduced train speeds, additional inspection and reinstallation costs, which translate into train delays, downtime, lost productivity and lost profitability for the railroads. Current methods of attaching studs to rails appear to exceed the critical (phase transformation) temperature in the rail material. There have been cases where this has resulted in formation of martensite in the stud-to-rail bond area during cooling. A brittle phase like martensite can produce fractures when stress is applied. Additionally, liquid metal embrittlement has been found in weld joints that involve the use of a brazing compound or solder to attach a signal wire. Methods that involve drilling for a plug attachment through the neutral axis of the rail result in decreased but acceptable fatigue performance. In an effort to avoid damage to the rail, studs have been moved from their ideal location (on the side of the rail head) to the middle of the web, close to or at the rail neutral axis. However, this location for studs causes other problems — wires and studs are highly prone to interfere with maintenance-of-way equipment. Under funding from the Federal Railroad Administration, EWI has developed and patented an inertia friction welding (IFW) process that is a field-portable, repeatable, and reliable solution for signal-wire attachments; in addition, the solid-state bonding mechanism provides advantages over the existing bonding solutions. IFW is used to weld a stud of dissimilar metal to rail, which in turn allows a signal wire to be connected.

Several weld stud alloys were chosen for process feasibility trials. These trials identified parameters that produced solid-state welds between the stud and rail with no martensite at or near the bond line. Further experimental trials were conducted to define a range for rotational speed and welding thrust load. Repeatability testing was also conducted to ensure that there is no evidence of martensite at or near the bond line after multiple stud weld-remove-and-repair cycles. A conceptual design of a field-portable rail inertia welder, based on EWI’s patented portable inertia welding technology, has been completed. The welder is lightweight and capable of being powered by a small electric motor. Internal timing and process controls can maintain and deliver weld quality. The simplicity of the process will yield consistent joint performance with minimal operator training and a variety of environmental conditions. Research is being conducted to examine the reliability of the process through a series of bending fatigue tests, corrosion tests and in service testing.
Analyzing the Progression From Single to Double Track Networks
Authors: Sogin Samuel L. , Dick C. Tyler , Lai Yung-Cheng , Barkan Christopher P. L.
Published: November 2013

Long term demand for rail transportation in North America is projected to increase considerably in the coming decades. A significant portion of the routes in the United States are single track with passing sidings. Eventually, the second mainline track will become necessary to maintain network fluidity. However, the full funding for the second track may not be available all at once; subsequently the track can be phased in over time creating a hybrid track configuration. Depending upon the traffic characteristics, traffic will transition from a delay characteristic of single track to a delay characteristic of double track. A response surface model was developed that tested various factors including the amount of second main track added, traffic volume, traffic composition, and the speed differential between train types. Design of experiments software (JMP) was used in conjunction with railway simulation software (Rail Traffic Controller) to conduct the analysis. The benefit of full double track can be realized for high priority trains with partial double-track. However, the low priority traffic may not experience double-track-like performance until nearly the entire second mainline track is installed. The results suggest a linear relationship between miles of second mainline track added and reduction in train delay. The maximum speed of the freight train has a great impact on train delays in a congested network. These results further the understandings of key mainline interactions between passenger and freight trains. In addition the models presented will facilitate the development of an optimal incremental upgrade model for capacity expansion. Also, the methodology presented can be adopted to analyze the progression from double to triple track.
Railway Engineering Education Symposium (REES) — Universities and Industry Collaborate to Develop Railway Education
Authors: Lautala Pasi T. , Dick C. Tyler , McKinney James L. , Clarke David B.
Published: November 2013

The national emphasis on highway transportation and a lack of demand for graduates in rail related fields led to a decades long neglect of rail transportation and engineering education by universities in the United States (U.S.). However, the vitality of the private sector freight railroads, along with a growing interest in rail passenger transportation is creating a strong demand for graduates with rail expertise, particularly in engineering and related technical fields. This has re-energized the academic community, and several universities are currently either investigating or implementing rail-related programs. They are finding, however, that the information and knowledge needed for railway engineering course development in the civil, mechanical and electrical fields is hard to find. It has been so long since most U.S. universities offered rail related courses that few present day faculty have expertise in the subject.

The American Railway Engineering and Maintenance of Way Association (AREMA) has teamed up with academia to address the problem through an innovative Railway Engineering Education Symposium (REES). This program brings university professors together to learn the basics of rail transportation and railway civil engineering and to return with materials that can be used for course implementation. REES has been organized biannually since 2008 and is considered a great success, making it a model for extension to railway mechanical and electrical engineering. This paper describes the reasoning behind development of REES, content and organization of the symposium, and its evolution. It also describes REES outcomes based on participant surveys conducted after each event and provides examples showing how universities have used REES to launch railway focused classes.
Creating Scanning Pattern Maps of Driver Fixations During Hazards
Authors: Hardy A. F. , Hill J. D.
Published: November 2013

Previous research has shown that drivers only look for a train about 33% of the time at railroad crossings. With driver inattention composing a large proportion of reported accidents, there exists a need to be able to quantify exactly what a driver fixates on over the course of a drive. This paper presents a method using simulated railroad situations as a hazard-medium to create driving scan pattern maps over the course of a long drive.
Comparison Between Wayside Storage and Reversible Thyristor Controlled Rectifiers (RTCR) for Heavy Rail Applications
Authors: Gelman Vitaly
Published: November 2013

There had been a substantial interest in the traction community to use wayside Energy Storage Systems (ESS) to better utilize train braking energy and thus achieve reduction of energy cost and peak power, and voltage stabilization. An alternative solution to reach the same goals is using recuperating (also called regenerating) traction power stations such as a Reversible Thyristor Controlled Rectifiers (RTCR). The paper compares advantages and disadvantages of ESS of three most common types — flywheels, batteries and supercapacitors — and RTCR. The analysis takes into account size, capital cost, the “round trip” energy losses and energy savings for heavy rail applications.
Review of State-Level Loan and Grant Funding Programs for Local Freight Rail Infrastructure
Authors: Sperry Benjamin R. , Morgan Curtis A.
Published: November 2013

This paper reports the results of a comprehensive review of state-level loan and grant funding programs specifically for local freight railroad infrastructure improvements. A total of 33 unique funding programs exist in 24 states. A majority of the programs are administered through the State DOT; however, other agencies can be involved. Programs typically offer a low-interest loan, grant, or a combination of loan and grant assistance; however, some loan programs allow for conversion to a grant if performance targets (typically jobs or local carloads) are achieved. Eligible entities typically include public agencies, freight railroad companies, or private industry. While these programs appear to be providing local communities with much-needed funding for rail projects, this review finds that administrative details of state-level funding programs within the public domain, such as published project selection criteria or a clear process of decision-making for funding, are the exception rather than the rule. Furthermore, ex post evaluation of project outcomes appears to be rare, underscoring the need for greater transparency in reporting of funding awards and assessment of how funding has been used to advance economic development goals. The findings from this paper can be used by state and local policymakers considering the creation of loan or grant funding programs for freight railroad infrastructure projects or by those who are seeking to improve existing programs.
Analysis of Passenger Transfer Patterns Based on Transit Smart Card Data in Seoul
Authors: Song Ji-Young , Eom Jin-Ki
Published: November 2013

This study analyzes the transfer patterns of passengers in Seoul based on transit smart card data that was observed in 2010. The smart card recorded maximum four times of transfer and reported that approximately 90% of trips were less than one transfer and the remains were more than 2 transfers. We focus on trips with more than 3 transfers to figure out the relationship between transit service and regional connectivity. The results show that the average travel time, distance, fare are 45 minutes, 18.3km, and 1,119(KW) respectively. We develop a map for investigating transfer patterns at a regional level (dong and gu). By doing this, three types of transfers are observed as: 1) trips of which origin and destination is either same or near, 2) trips with middle distance (shorter then 6km), and 3) long distance (from 6km to 12km) trip with low transit connectivity.
Image Detection System and its Application for Dynamic Wheel/Rail Contact in High Speed Railway
Authors: Wang Ping , Chen Rong , Xiao Jieling
Published: November 2013

Dynamic wheel/rail contact is the core connecting link between vehicle and track under high speed running condition. Based on optical technology, photoelectric technology, digital image processing techniques and software engineering, a image detection system for dynamic wheel/rail contact is developed. This system is used to get the distribution law of wheel/rail contact points on rail head and wheel tread under high speed running condition. High-speed cameras are placed at the rail’s inside and outside. When the train passes the test zone at high-speed, the wheel/rail dynamic contact image can be obtained. A complete wheel/rail contact space trace and contact state are also obtained through process of image feature recognition. The system consists of such hardware as camera imaging and optical unit, image acquisition and storage devices, lighting sources, trigger unit and a image processing software. There is a key step in image acquisition and processing. Image with distortion is restored by the distortion correction function for distortion-free images. Then according to the markers information of calibration parameter, inside and outside part of the corrected image is stitched to form a complete image of wheel/rail contact. This system is verified by laboratory test assembly and field measurement. It can accurately collect clear wheel/rail contact image and qualitatively present the wheel/rail contact state. It can also provide the wheel and rail contour curve and the wheel/rail normal distance of each section. This has provided data support and visual reference for the further study on wheel/rail contact state of high-speed railway.
Development and Implementation of a Trespass Location Severity Analysis on a Commuter Rail Right of Way
Authors: daSilva Marco
Published: November 2013

The United States Department of Transportation’s (USDOT) Research and Innovative Technology Administration’s John A. Volpe National Transportation Systems Center (Volpe Center), under the direction of the USDOT Federal Railroad Administration (FRA) Office of Research and Development (R&D), is conducting a Trespass Prevention Research Study (TPRS) in the city of West Palm Beach, Florida. The main objective of this research is to demonstrate potential benefits, including documenting best practices and lessons learned, of implementation and evaluation of trespass prevention strategies on the rail network in West Palm Beach, Florida and all of its rights-of-way.

This paper will detail the development and implementation of a risk based data analysis to determine the locations of highest trespass risk along the TriRail commuter rail corridor through the City of West Palm Beach, FL. This feeds into the overall study objective by providing a methodology for prioritizing safety improvement programs for high-risk trespass locations.

The research team used a hazard analysis process based on the U.S. Department of Defense’s MIL-STD-882 and the APTA hazard identification/resolution processes. The adaptation of this methodology facilitated the systematic identification, analysis, and resolution/mitigation of hazards for this study.

The research team also developed a risk-based prioritization algorithm for analyzing the trespass issue on the corridor. The hazard analysis and risk-based prioritization algorithm were used to identify several trespass high-risk areas along the TriRail corridor. The results of the analysis have been used by the study’s stakeholder group, composed of railroads, state and local agencies, and their safety partners, to develop a set of mitigation strategies for those higher-risk locations as identified though this analysis.
Modification of the Relation Between Grade and Curvature — Purpose, Reasons, and Advantages
Authors: Hasan Nazmul
Published: November 2013

In cases where grades and horizontal curves are combined, the current relation between the grade and the degree of curve, D, is defined as follows:G+cD=r

in which

G = The maximum allowable compensated grade in %,

D = Degree of curve,

c = 0.04, compensation factor in % grade per degree of curve,

r = The maximum grade achievable by the train in %.

The above relation is a design tool to combine grade and curvature. The author intends to modify the above relation for two purposes —

• to make the relation more rational for combining grade and curve for LRT design, and

• to make the relation useful in computing the installation slope of special trackwork.

A modified formula is suggested as under:G+cD=kr

in which

c = compensation factor in % grade per degree of curve determined on the basis of curvature,

k = grade reduction factor arbitrarily chosen between 0.2 ∼ 1 depending on curvature and type of rail.

The justification of the proposed modification and the advantages of the modified formula are discussed in details.
Use of Archard’s Wear Law for the Calculation of Uniform Wheel Wear of High Tonnage Freight Vehicles
Authors: Casanueva Carlos , Jönsson Per-Anders , Stichel Sebastian
Published: November 2013

Wheel profile evolution has a large influence on track and wheelset related maintenance costs. It influences important parameters such as equivalent conicity or contact point positioning, which will affect the dynamic behavior of the vehicle, in both tangent track and curve negotiation. High axle loads in freight wagons may increase both the wheel wear and the damage caused by vehicles with both new and already worn profiles. A common profile in Europe is the S1002 profile, developed for rail inclination 1/40. In Sweden rail inclination is 1/30, so contact conditions might not be optimal. The presented work uses Archard’s wear law to analyze the profile wear evolution in a two axle freight vehicle with Unitruck running gear on the Swedish network. This wear calculation methodology has been successfully used to predict uniform wear in passenger vehicles. First, the vehicle model has been optimized in order to improve the speed of the wear simulations. Experimental measurements of wheel profiles have been performed in order to validate the simulations. The conclusion is that the wear methodology successfully used to predict uniform wheel wear in passenger vehicles cannot be directly applied for the calculation of wheel profile evolution in high tonnage freight vehicles. The influence of block brakes or switches and crossings cannot be dismissed when calculating uniform wheel wear in these cases.
Tank Car Puncture Analyses for Various Impactors and Impact Conditions
Authors: Kirkpatrick Steven W. , Gonzalez Francisco , Alexy Karl
Published: November 2013

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture prediction. However, the evaluations in these past studies were primarily performed for a few idealized impact scenarios.

This paper describes a research program to evaluate railroad tank car puncture behaviors under more general impact conditions. The approach used in this research program was to apply a tank impact and puncture prediction capability using detailed finite element analyses (FEA). The analysis methodologies apply advanced damage and failure models that were validated by series of material tests under various loading conditions. In this study, the analyses were applied to investigate the tank puncture behaviors for a wide range of impact conditions.
Noise and Vibration Reduction Performance Test of Rubber Damping Pad Under Slab Track in High Speed Railway
Authors: Chen Rong , Wang Ping , Guo Likang
Published: November 2013

Rubber damping pad under ballastless slab track can isolate structure vibration and noise so as to reduce stress and wear of railway track components. In order to make scientific evaluation on the influence of rubber damping pad on the dynamic response of the track structure, focusing on the engineering practice of Chengdu-GuanDujiangyan high-speed railway, comparative test of slab track with and without rubber damping pad is carried out by using acceleration sensors, acoustic sensors, and dynamic data acquisition system. Spectrum analysis of vibration acceleration and noise test results shows that rubber damping pad under track slab can greatly isolate the substructure vibration of the track, the bridge vibration and ground vibration; vibration level of the base slab under the pad is reduced by about 20.1dB; the rubber damping pad can reduce some of the structure noise caused by the bridge structure vibration, but it has no significant effect on noise reduction of the whole system due to the influences of EMU pantograph’s arc noise, severe air turbulence noise and field test environment.
Effect of Number of Bars and Reciprocation Speed on Residence Time of Particles on a Moving Grate
Authors: Nakamura Masato R. , Singh Jason
Published: November 2013

The moving grate systems of waste-to-energy (WTE) mass-burn combustion chambers are designed for providing efficient flow and mixing of the municipal solid waste (MSW) over the length of the grade. This study presents results from a numerical analysis of the effect of number of reciprocating bars and reciprocation speed on the degree of mixing and residence time of MSW particles on the grate. A particle-based bed model of MSW and a physical model of reverse-acting grate were used in order to quantify the mixing diffusion coefficient of MSW particles. We analyzed the particle mixing with different parameters: particle size (d = 6–22cm diameter), reciprocation speed of moving bars (Rr = 0–90recip./h), and number of moving bars (Nb = 0 to 16 bars). This combination of mathematical modeling and experimental work has shown that: (1) different particle sizes result in different residence times, according to the Brazil Nut Effect (BNE) (2) The number of moving bars (from 0 to 16 bars) of a reverse-acting grate has the net effect of increasing the mean residence time of small and medium sized particles, while decreasing that of large particles. (3) The bar height, h, was found to be one of the major geometric parameters influencing mixing diffusion coefficient, D, and residence time.
Numerical Analysis of the Size and Shape of New York City Municipal Solid Waste (NYCMSW) and Residues for Combustion Chamber Design
Authors: Diaconu Florin , Nakamura Masato R.
Published: November 2013

The size and shape of New York City municipal solid waste (NYCMSW) and combustion residues (ashes) are numerically analyzed in order to investigate the size reduction of particles on the grate of a waste-to-energy (WTE) combustion chamber. It is also necessary for designing a new combustion chamber, due to the heterogeneous MSW particles. About 360 MSW particles for this study were sampled in the black bags collected in residential areas at five boroughs of New York City. Also about 210 ash particles from a WTE combustion chamber were sampled. Length, breadth, perimeter and area of each MSW and ash particle are measured by means of image analysis that is more accurate than sieve analysis. Based on the image analysis, the particle size distributions (PSiD) and particle shape distributions (PShD) of MSW and residues were created. The mean size of NYCMSW was found to be 12.8cm and standard deviation of the MSW PSiD to be 6.4. Also mean size and standard deviation of the ash PSiD to be 2.4cm and 0.5889, respectively. Also Three types of shape factors (aspect ratio, roundness and sphericity) are used for creating 3 PShDs (aspect-ratio distributions, roundness distributions and sphericity distributions). Based on the similarity of the particle shapes quantified as these shape factors, the particles of MSW and residues are divided into 9 clusters by means of cluster analysis. This cluster analysis showed categorized characteristics of particle shapes that can be used for predicting surface areas of particles and mobility of particles in MSW bed on the traveling grate, both of which are major parameters for simulating combustion process in WTE systems.
Growth and wood properties of genetically improved loblolly pine: propagation type comparison and genetic parameters
Authors: Antony Finto , Schimleck Laurence R. , Jordan Lewis , Hornsby Benjamin , Dahlen Joseph , Daniels Richard F. , Clark Alexander , Apiolaza Luis A. , Huber Dudley
Published: November 2013

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties.
Relative influence of contextual factors on deliberation and development of cooperation in community-based forest management in Ontario, Canada
Authors: Robson Mark
Published: November 2013

Co-management of forests has been reported from more than fifty countries and stakeholder advisory committees have become central to forest planning in Canada. Scientists tend to agree that local users are capable of self-organising to manage resources more effectively than state agencies alone, whether jointly with governments or with considerable autonomy. Little, however, is known about how the network of contextual influences helps, hinders, or overrides the deliberation that facilitates the development of cooperation critical for co-management success. The objectives of the paper are to identify the relative influence of contextual factors, participants’ sense of control over contextual factors, and effects on performance. In a comparative case study of two stakeholder advisory committees in Ontario, Canada, the objectives are addressed by identifying and analysing advisory committee thinking about consensus building using network analysis of group cognitive maps. The paper concludes with three lessons regarding how the mix of hierarchical, market, and community institutions that influence community-based deliberation can be coordinated for effective forest management.
Vacuum expansion in arbitrary–gauge Lyra geometry
Authors: Hova Hoavo
Published: November 2013

We propose a cosmological model containing a cosmological term in arbitrary gauge in Lyra’s geometry. In the absence of matter fields (such as radiation or baryonic), a constant cosmological term does not lead to the de Sitter universe as it is seen in Riemannian geometry, while a time-varying cosmological term can drive the universe into an accelerated expansion.
LRS Bianchi type I stiff fluid inflationary universe with variable bulk viscosity
Authors: Bali Raj , Singh Swati
Published: November 2013

Stiff fluid inflationary cosmological model with variable bulk viscosity in the frame work of locally rotationally symmetric (LRS) Bianchi type I space–time, is investigated. To get the deterministic solution, we have also assumed that σ is proportional to θ and ζθ = constant = α where σ is shear, θ the expansion, and ζ the coefficient of bulk viscosity. The ansatz ζθ = constant, was found to connect with the occurrence of Little Rip cosmology using Friedmann–Robertson–Walker metric given by Brevik et al. (Phys. Rev. D, 84, 103508 (2011)). We find that the model has constant expansion but represents accelerating phase. The model in general represents an anisotropic universe but in special case, it leads to an isotropic one. The spatial volume increases exponentially with time representing the inflationary scenario. The presence of bulk viscosity tends to increase the inflationary phase. Also, the model leads to the de Sitter model in a special case. The presence of bulk viscosity prevents the matter density to vanish at late time. The energy conditions as given by Kolassis et al. (Classical Quantum Gravity, 5, 1129 (1988)). Chatterjee and Banerjee (Gen. Relativ. Gravitation, 36, 303 (2004)) are also discussed. We find that the energy conditions are satisfied for stiff fluid inflationary universe with variable bulk viscosity.
A ΣΔ MODULATOR USING GAIN-BOOST CLASS-C INVERTER FOR AUDIO APPLICATIONS
Authors: LUO HAO , HAN YAN , CHEUNG RAY C. C. , CAO TIANLIN , LIU XIAOPENG , GAO FENG
Published: November 2013

This paper provides an audio 2-1 cascaded ΣΔ modulator using a novel gain-boost class-C inverter. The gain-boost class-C inverter behaves as a subthreshold amplifier. By introducing a gain-boost module, the inverter DC-gain is increased from 48 dB to 67 dB. The gain-boost class-C inverter consumes 57 μW at 1.2-V supply, where the gain-boost module consumes only 3 μW. In addition, an on-chip body bias technique is introduced to compensate the process and supply voltage variations of the class-C inverter. The proposed inverter-based ΣΔ modulator chip is implemented in 0.13-μm CMOS process, and achieves 86-dB peak-signal to noise and distortion ratio (SNDR) and 90-dB dynamic range (DR) over 22.05-KHz bandwidth at 1.2-V supply consuming 360 μW, which demonstrates that the gain-boost class-C inverter is particularly suitable for micro-power high-resolution applications.
UNCERTAIN BUCKLING AND RELIABILITY ANALYSIS OF THE PIEZOELECTRIC FUNCTIONALLY GRADED CYLINDRICAL SHELLS BASED ON THE NONPROBABILISTIC CONVEX MODEL
Authors: BI R. G. , HAN X. , JIANG C. , BAI Y. C. , LIU J.
Published: November 2013

The uncertain buckling and reliability of the laminated piezoelectric functionally graded material (FGM) cylindrical shells subjected to axially compressed loads are investigated in this research. Considering the shear deformation, the buckling governing equations of the piezoelectric FGM cylindrical shells are derived on the basis of Donnell assumptions. And then the nonprobabilistic convex model is introduced to predict the uncertain buckling loads of the piezoelectric FGM cylindrical shells resulting from the unavoidable scatter in structural parameters. Finally, the reliability degree of the structures is obtained by computing the ratio of the multidimensional volume falling into the reliability domain to the one of the whole convex model. Numerical results indicate that uncertainties in structural parameters have significant effects on the critical buckling loads and reliability of the piezoelectric FGM cylindrical shells.
The Role of Mites in Insect-Fungus Associations
Authors: Hofstetter R.W. , Moser J.C.
Published: November 2013

The interactions among insects, mites, and fungi are diverse and complex but poorly understood in most cases. Associations among insects, mites, and fungi span an almost incomprehensible array of ecological interactions and evolutionary histories. Insects and mites often share habitats and resources and thus interact within communities. Many mites and insects rely on fungi for nutrients, and fungi benefit from them with regard to spore dispersal, habitat provision, or nutrient resources. Mites have important impacts on community dynamics, ecosystem processes, and biodiversity within many insect-fungus systems. Given that mites are understudied but highly abundant, they likely have bigger, more important, and more widespread impacts on communities than previously recognized. We describe mutualistic and antagonistic effects of mites on insect-fungus associations, explore the processes that underpin ecological and evolutionary patterns of these multipartite communities, review well-researched examples of the effects of mites on insect-fungus associations, and discuss approaches for studying mites within insect-fungus communities.
Chemoprevention of Prostate Cancer
Authors: Vemana Goutham , Hamilton Robert J. , Andriole Gerald L. , Freedland Stephen J.
Published: November 2013

Large prospective randomized trials, such as the Prostate Cancer Prevention Trial (PCPT), Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial, and Selenium and Vitamin E Cancer Prevention Trial (SELECT), have provided practitioners with considerable data regarding methods of treatment and prevention of prostate cancer. The best-studied medications for prevention are 5 alpha-reductase inhibitors. Their efficacy and side effects are well characterized. Other medications, dietary nutrients, and supplements have not been as well studied and generally do not demonstrate efficacy for disease prevention with an acceptable level of evidence.
The Role of Gut Hormone Peptide YY in Energy and Glucose Homeostasis: Twelve Years On
Authors: Manning Sean , Batterham Rachel L.
Published: November 2013

Although the role of peptide YY (PYY) as a regulator of energy homeostasis was first highlighted only in 2002, our understanding of the physiological role of PYY has since rapidly advanced. In recent years, insights from mechanistic studies in patients undergoing bariatric surgery, from pancreatic islet research, from functional neuroimaging studies, and from exercise research have greatly added to the field, and these areas provide the focus of discussion for this narrative review. We critically discuss recent findings relating to the role of PYY in mediating the beneficial effects of bariatric surgery, the role of PYY in glucose homeostasis, the role of hepatoportal PYY in mediating its central physiological effects, the specific modulation of brain regions by PYY, and the exercise-induced PYY response.
Combining the Power of Stories and the Power of Numbers: Mixed Methods Research and Mixed Studies Reviews
Authors: Pluye Pierre , Hong Quan Nha
Published: November 2013

This article provides an overview of mixed methods research and mixed studies reviews. These two approaches are used to combine the strengths of quantitative and qualitative methods and to compensate for their respective limitations. This article is structured in three main parts. First, the epistemological background for mixed methods will be presented. Afterward, we present the main types of mixed methods research designs and techniques as well as guidance for planning, conducting, and appraising mixed methods research. In the last part, we describe the main types of mixed studies reviews and provide a tool kit and examples. Future research needs to offer guidance for assessing mixed methods research and reporting mixed studies reviews, among other challenges.
Service Quality of Online Shopping Platforms: A Case-Based Empirical and Analytical Study
Authors: Choi Tsan-Ming , Chow Pui-Sze , Kwok Bowood , Liu Shuk-Ching , Shen Bin
Published: November 2013

Customer service is crucially important for online shopping platforms (OSPs) such as eBay and Taobao. Based on the well-established service quality instruments and the scenario of the specific case on Taobao, this paper focuses on exploring the service quality of an OSP with an aim of revealing customer perceptions of the service quality associated with the provided functions and investigating their impacts on customer loyalty. By an empirical study, this paper finds that the “fulfillment and responsiveness” function is significantly related to the customer loyalty. Further analytical study is conducted to reveal that the optimal service level on the “fulfillment and responsiveness” function for the risk averse OSP uniquely exists. Moreover, the analytical results prove that (i) if the customer loyalty is more positively correlated to the service level, it will lead to a larger optimal service level, and (ii) the optimal service level is independent of the profit target, the source of uncertainty, and the risk preference of the OSP.
Improvement of the Dynamic Responses of Heart Rate Variability Patterns after Needle and Laser Acupuncture Treatment in Patients with Burnout Syndrome: A Transcontinental Comparative Study
Authors: Litscher Gerhard , Liu Cun-Zhi , Wang Lu , Wang Lin-Peng , Li Qian-Qian , Shi Guang-Xia , Gaischek Ingrid , Litscher Daniela , Wang Xiao-Min
Published: November 2013

We investigated manual needle and laser needle acupuncture as a complementary therapy for patients with burnout syndrome. Twenty patients with a mean age ± SD of 38.7 ± 8.4 years were assigned to two groups, each consisting of ten patients. One group was treated with manual needle acupuncture and the other with laser needle acupuncture. Heart rate, heart rate variability (HRV), and a new score called dynamic acupuncture treatment score (DATS) served as evaluation parameters. The study documented significant effects on heart rate after needle acupuncture treatment and significant effects on HRV caused by both needle and laser needle acupuncture. Based on new neurovegetative acupuncture treatment evaluation scores, it can be stated that both noninvasive laser needle acupuncture and manual needle acupuncture have the potential to be a powerful approach for evidence-based complementary treatment of patients with burnout syndrome. Further transcontinental studies to verify or refute the preliminary findings are in progress.
An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique
Authors: Shafi Nighat , Siddiqui Farhan Ahmed , Naseem Huma , Sher Nawab , Zubair Arif , Hussain Azhar , Sial Ali Akbar , Baig Mirza Tasawer
Published: November 2013

This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2 receptor antagonists (cimetidine, ranitidine, and famotidine) by one of the spectroscopic technique (UV spectrophotometery) and separation technique such as high‐performance liquid chromatography (HPLC). The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry‐related journals has been compiled in its review. A synopsis of reported spectrophotometric and high‐performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.
MCML D-Latch Using Triple-Tail Cells: Analysis and Design
Authors: Gupta Kirti , Pandey Neeta , Gupta Maneesha
Published: November 2013

A new low-voltage MOS current mode logic (MCML) topology for D-latch is proposed. The new topology employs a triple-tail cell to lower the supply voltage requirement in comparison to traditional MCML D-latch. The design of the proposed MCML D-latch is carried out through analytical modeling of its static parameters. The delay is expressed in terms of the bias current and the voltage swing so that it can be traded off with the power consumption. The proposed low-voltage MCML D-latch is analyzed for the two design cases, namely, high-speed and power-efficient, and the performance is compared with the traditional MCML D-latch for each design case. The theoretical propositions are validated through extensive SPICE simulations using TSMC 0.18 µm CMOS technology parameters.
Machine Directional Register System Modeling for Shaft-Less Drive Gravure Printing Machines
Authors: Liu Shanhui , Mei Xuesong , Li Jian , Ma Li'e
Published: November 2013

In the latest type of gravure printing machines referred to as the shaft-less drive system, each gravure printing roller is driven by an individual servo motor, and all motors are electrically synchronized. The register error is regulated by a speed difference between the adjacent printing rollers. In order to improve the control accuracy of register system, an accurate mathematical model of the register system should be investigated for the latest machines. Therefore, the mathematical model of the machine directional register (MDR) system is studied for the multicolor gravure printing machines in this paper. According to the definition of the MDR error, the model is derived, and then it is validated by the numerical simulation and experiments carried out in the experimental setup of the four-color gravure printing machines. The results show that the established MDR system model is accurate and reliable.
Synthesis and Optical Characterization of Sulfonated Polyaniline/Single-Walled Carbon Nanotube/Zinc Sulphide Nanocomposite
Authors: Agrawalla Rajesh K. , Paul Rima , Chakraborty Amit K. , Mitra Apurba K.
Published: November 2013

Polyaniline functionalized with sulfonate groups (SPANI) shows excellent solubility in water. Single-walled carbon nanotubes functionalized with carboxylic groups (f-SWCNTs) and then hybridized with freshly prepared zinc sulphide (ZnS) nanocrystals have been found to be good luminescent material with tuned emission properties. Nanocomposite of sulfonated polyaniline with embedded SWCNT/ZnS nanohybrid fibers has been prepared by a simple solution mixing process and characterized by using high resolution transmission electron microscopy (HRTEM), X-ray diffractometry, Raman spectroscopy, FTIR spectroscopy, and thermogravimetric analysis (TGA). The study of optical properties by UV-vis absorption and photoluminescence spectroscopy reveals that the composite is a luminescent material of enhanced emission intensity in the visible region of the spectrum.