bluuebunny/crossref_metadata_2025 huggingface dataset:
An integrative review of the antecedents and consequences of lateral hiring
Authors: Amankwah-Amoah Joseph
Published: July 2015

Purpose

– Although there is a burgeoning stream of research on lateral hiring (LH), lack of integration of the literature has obscured the past accomplishments and future directions remain unclear. The purpose of this paper is to review and synthesise the existing literature on LH in the spirit of further development of this field.

Design/methodology/approach

– The paper is based on an extensive review of the literature across multiple social science disciplines.

Findings

– The study integrates the existing streams of research in such a way that human resources and personnel practitioners see the relevance of research and how they can mitigate the negative effects of LH. The study demonstrates how employers can acquire, develop and retain scarce human capital (HC) to help improve their competitiveness.

Research limitations/implications

– The main limitation of the review is that the search might have overlooked studies that employed specialised terminologies or keywords not used here.

Practical implications

– The study outlines a number of implications for theory and human resource management.

Originality/value

– This study advances research on LH by developing an integrated conceptual framework of how the attributes of the target employee, current employer and potential employer influence how LH is considered, instigated, responded to and accepted. The findings highlight the increasingly important role played by HC in developing sustainable competitive advantage.
Beyond the unidimensional collective leadership model
Authors: Mendez Maria J , Howell Jon P. , Bishop James W.
Published: July 2015

Purpose

– A theoretical analysis evidences the existence of multiple patterns of collective leadership and serves as foundation for the proposal of a two-dimensional model of collective leadership, which evaluates leadership sharedness (the extent to which leadership roles are shared by group members), and leadership distribution (the extent to which different leadership roles are permanently assigned to group members). The relationship between these dimensions and committee effectiveness is further tested.

Design/methodology/approach

– A social networks methodology is used with a sample of 28 committees. Two complementary network properties (centralization and density) are used to operationalize leadership sharedness and a new measure is developed to operationalize leadership distribution. Stepwise regressions test the relation between collective leadership dimensions and performance.

Findings

– The model proposed advances the understanding of collective leadership’s internal dynamics and facilitates empirical comparisons of the effectiveness of various forms of collective leadership. The highest committee performance was found in groups where members contribute equally to charismatic and supportive leadership but only when these equal contributions were high. In collective directive and participative leadership, however, equality of contribution was associated to higher performance independently on the strength of members’ contributions. No relationship was found between the distribution of leadership roles among group members and committee performance.

Research limitations/implications

– A small sample size may have reduced hypothesis testing power. The intraclass corrections (ICC(2)) were lower than recommended. Finally, results cannot be extrapolated beyond committees, which have very unique characteristics due to their low typical interaction.

Practical implications

– Organizations can improve committee performance by ensuring high and equal participation of members in their group’s leadership through training and selection. Enhancing participation of all members in leadership requires special attention to women and members of minorities, that are typically attributed less leadership influence and whose commitment to the group may be hurt by lack of involvement.

Originality/value

– The two-dimensional model proposed goes beyond previously published models in exploring several aspects of collective leadership internal dynamics by advancing the understanding how different aspects of collective leadership patterns affect group performance.
The McGill library chapbook project: a case study in TEI encoding
Authors: Rankin Sharon , Lees Casey
Published: July 2015

Purpose

– The purpose of this case study is to describe a multi-year text encoding initiative (TEI) project that took place in the McGill University Library, Rare Books and Special Collections.

Design/methodology/approach

– Early nineteenth century English language chapbooks from the collection were digitized, and the proofed text files were encoded in TEI, following Best Practices for TEI in Libraries (2011).

Findings

– The project coordinator describes the TEI file structure and customizations for the project to support a distinct subject classification of the chapbooks and the encoding of the woodcut illustrations using the Iconclass classification.

Research limitations/implications

– The authors focus on procedures, use of TEI data elements and encoding challenges.

Practical implications

– This paper documents the project workflow and provides a possible model for future digital humanities projects.

Social implications

– The graduate students who participated in the TEI encoding learned a new suite of skills involving extensible markup language (XML) file structure and the application of a markup language that requires interpretation.

Originality/value

– The McGill Library Chapbook Project Web site, launched in 2013 now provides access to 933 full-text works.
Responses of Linear and Nonlinear Oscillators to Fractional Gaussian Noise With Hurst Index Between 1/2 and 1
Authors: Lin Deng Mao , Qiu Zhu Wei
Published: July 2015

The responses of linear and nonlinear oscillators to fractional Gaussian noise (fGn) are studied. First, some preliminary concepts and properties of fractional Brownian motion (fBm) and fGn with Hurst index 1/2<H<1 are introduced. Then, the exact sample solution, correlation function, spectral density, and mean-square value of the response of linear oscillator to fGn are obtained. Based on the sample solution, it is proved that the long-range correlation index of displacement response of linear oscillator is the same as that of excitation fGn, i.e., 2-2H, while the velocity response has no such long-range correlation. An interesting discovery is that the ratio of kinetic energy to total energy decreases as increasing Hurst index H. Finally, for the responses of one and two degrees-of-freedom (DOF) nonlinear oscillators to fGn, the equivalent linearization method is applied to obtain the sample functions, correlation functions and mean-square values of the responses. Plenty of digital simulation results are obtained to support these solutions. It is shown that the approximate solution is effective for weakly nonlinear oscillators and it is feasible to apply the equivalent linearization to study multi-DOF weakly nonlinear oscillators.
A Multilevel Upscaling Method for Material Characterization of Additively Manufactured Part Under Uncertainties
Authors: Gorguluarslan Recep M. , Park Sang-In , Rosen David W. , Choi Seung-Kyum
Published: July 2015

An integrated multiscale modeling framework that incorporates a simulation-based upscaling technique is developed and implemented for the material characterization of additively manufactured cellular structures in this paper. The proposed upscaling procedure enables the determination of homogenized parameters at multiple levels by matching the probabilistic performance between fine and coarse scale models. Polynomial chaos expansion (PCE) is employed in the upscaling procedure to handle the computational burden caused by the input uncertainties. Efficient uncertainty quantification is achieved at the mesoscale level by utilizing the developed upscaling technique. The homogenized parameters of mesostructures are utilized again at the macroscale level in the upscaling procedure to accurately obtain the overall material properties of the target cellular structure. Actual experimental results of additively manufactured parts are integrated into the developed procedure to demonstrate the efficacy of the method.
Investigation in the Near-Field of a Row of Interacting Jets
Authors: Ghahremanian Shahriar , Moshfegh Bahram
Published: July 2015

Multiple interacting jets (confluent jets) are employed in many engineering applications, and the significant design factors must be investigated. Computational fluid dynamics (CFD) is used to numerically predict the flow field in the proximal region of a single row of round jets. The numerical results that are obtained when using the low Reynolds k-ε are validated with the experimental data that are acquired by particle image velocimetry (PIV). PIV was used to measure mean velocity and turbulence properties in the proximal region of a row of six parallel coplanar round air jets with equidistant spacing at low Reynolds number (Re = 3290). The low Reynolds k-ε underpredicts the streamwise velocity in the onset of the jets' decay. The characteristic points are determined for various regions between two neighboring jets. The comparison of the merging point (MP) and the combined point (CP) computed from measurements and simulations shows good agreement in the different regions between the jets. In this study, a computational parametric study is also conducted to determine the main effects of three design factors and the interactions between them on the flow field development using response surface method (RSM). The influences of the inlet velocity, the spacing between the nozzles, and the diameter of the nozzles on the locations of the characteristic points are presented in the form of correlations (regression equations). CFD is used to numerically predict the characteristic points for a set of required studies, for which the design values of the simulation cases are determined by the Box–Behnken method. The results indicate that the spacing between the nozzles has a major impact on the flow characteristics in the near-field region of multiple interacting jets. The RSM shows that the inlet velocity has a marginal effect on the merging and CPs. All of the square terms are removed from the response equations of MP, and only one two-way interaction term between inlet velocity and spacing remains in the regression model with a marginal effect. The square of the nozzle diameter contributes in the regression equations of CP in some regions between the jets.
A Self-Adjusting Method for Real-Time Calculation of Thermal Loads in HVAC-R Applications
Authors: Fayazbakhsh M. A. , Bagheri F. , Bahrami M.
Published: July 2015

A significant step in the design of heating, ventilating, air conditioning, and refrigeration (HVAC-R) systems is to calculate room thermal loads. The heating/cooling loads encountered by the room often vary dynamically while the common practice in HVAC-R engineering is to calculate the loads for peak conditions and then select the refrigeration system accordingly. In this study, a self-adjusting method is proposed for real-time calculation of thermal loads. The method is based on the heat balance method (HBM) and a data-driven approach is followed. Live temperature measurements and a gradient descent optimization technique are incorporated in the model to adjust the calculations for higher accuracy. Using experimental results, it is shown that the proposed method can estimate the thermal loads with higher accuracy compared to using sheer physical properties of the room in the heat balance calculations, as is often done in design processes. Using the adjusted real-time load estimations in new and existing applications, the system performance can be optimized to provide thermal comfort while consuming less overall energy.
Reconfiguration Analysis of a Two Degrees-of-Freedom 3-4R Parallel Manipulator With Planar Base and Platform1
Authors: Kong Xianwen , Yu Jingjun , Li Duanling
Published: July 2015

This paper deals with a 2-DOF (degrees-of-freedom) 3-4R parallel manipulator (PM) with planar base and platform—a novel PM with multiple operation modes (or disassembly free reconfigurable PM) that can use the minimum number of actuated joints. At first, a set of constraint equations of the 3-4R PM are derived with the orientation of the moving platform represented using a Euler parameter quaternion (also Euler–Rodrigues quaternion) and then solved using the algebraic geometry method. It is found that this 3-4R PM has six 2-DOF operation modes, including the two expected spherical translation mode and sphere-on-sphere rolling mode when the PM was synthesized. The motion characteristics of the moving platform are obtained using the kinematic interpretation of Euler parameter quaternions with certain number of constant zero components, which was presented in a recent paper by the first author of this paper, instead of the eigenspace-based approach in the literature. The transition configurations, which are constraint singular configurations, among different operation modes are also presented. This work provides a solid foundation to the development and control of the 2-DOF 3-4R PM with both 2-DOF spherical translation mode and 2-DOF sphere-on-sphere rolling mode.
Drone-Based Experimental Investigation of Three-Dimensional Flow Structure of a Multi-Megawatt Wind Turbine in Complex Terrain
Authors: Subramanian B. , Chokani N. , Abhari R. S.
Published: July 2015

The aerodynamic characteristics of wakes in complex terrain have a profound impact on the energy yield of wind farms and on the fatigue loads on wind turbines in the wind farm. In order to detail the spatial variations of the wind speed, wind direction, and turbulent kinetic energy (TKE) in the near-wake, comprehensive drone-based measurements at a multi-megawatt (MW) wind turbine that is located in complex terrain have been conducted. A short-time Fourier transform (STFT)-based analysis method is used to derive time-localized TKE along the drone's trajectory. In upstream and in the near-wake, the vertical profiles of wind speed, wind direction, and TKE are detailed. There is an increase in the TKE from upstream to downstream of the wind turbine, and whereas, the characteristic microscale length scales increase with increasing height above the ground upstream of the turbine, in the near-wake the microscale lengths are of constant, smaller magnitude. The first-ever measurements of the pressure field across a multi-MW wind turbines rotor plane and of the tip vortices in the near-wake are also reported. It is shown that the pitch between subsequent tip vortices, which are shed from the wind turbines blades, increases in the near-wake as the wake evolves. These details of the near-wake can have an important effect on the subsequent evolution of the wake and must be incorporated into the three-dimensional (3D) field wake models that are currently under intensive development.
An Adaptive Wind Turbine Controller Considering Both the System Performance and Fatigue Loading
Authors: Ma Zheren , Shaltout Mohamed L. , Chen Dongmei
Published: July 2015

Wind energy is a clean and renewable source for electricity generation. To reduce the costs associated with wind power generation, development of a control methodology that maximizes the wind energy capture and mitigates the turbine fatigue loading is desired. In this paper, a new adaptive gain modified optimal torque controller (AGMOTC) for wind turbine partial load operation is presented. A gain-scheduling technique with an internal proportional integral (PI) control is developed to accelerate the controller's convergence to a reference tip speed ratio (TSR). The reference TSR is then adjusted to its optimal value in real-time through an adaptive algorithm capable of rejecting model uncertainties and estimation errors of the control gain. A fatigue mitigation method is also designed to reduce the impact of exacerbated tower bending moments due to the resonance effect. The proposed AGMOTC is evaluated based on the National Renewable Energy Laboratory (NREL) 5 MW wind turbine model using the NREL fast simulator. Simulation results have shown that the AGMOTC has improved efficiency and robustness in wind energy capture and reduced tower fatigue loading as compared to the traditional control technique.
2014 Drucker Medal Paper: A Derivation of the Theory of Linear Poroelasticity From Chemoelasticity
Authors: Anand Lallit
Published: July 2015

The purpose of this brief paper is to present a new derivation of Biot's theory of linear poroelasticity (Biot, M., 1935, “Le Probleḿe de la Consolidation des Matiéres Argileuses Sous une Charge,” Ann. Soc. Sci. Bruxelles,B55, pp. 110–113; Biot, M., 1941, “General Theory of Three-Dimensional Consolidation,” J. Appl. Phys., 12, pp. 155–164; and Biot, M., and Willis, D., 1957, “The Elastic Coefficients of the Theory of Consolidation,” J. Appl. Mech., 24, pp. 594–601) in a modern thermodynamically consistent fashion, and show that it may be deduced as a special case of a more general theory of chemoelasticity.
Double Block and Bleed Pipeline Isolations: Improving Safety/Decreasing Maintenance Costs
Authors: Dum Frank , Hamblin Patrick , Garaev Niyaz
Published: July 2015

Safety is always the number one focus of the pipeline industry. This paper will discuss how Double Block & Bleed (DB&B) maximizes safety during a pipeline isolation. In addition to safety, DB&B also maximizes project efficiency, which results in minimizing project and maintenance costs.

The goal of DB&B for both safety and efficiency is to approach 100 percent success in achieving a seal with no detectable seepage.

Pipeline isolations are frequently utilized for maintenance such as replacement of leaking block valves, cut out and repair of third party damage, and cut out and replacement of imperfections identified during inline inspection runs.

This paper will begin with a review of laboratory testing and calculation of DB&B efficiency, followed by one or more field case studies.
Pipeline Corrosion Integrity Management by Direct Assessment
Authors: Javia Shailesh
Published: July 2015

Integrity management of pipelines is a systematic, comprehensive and integrated approach to proactively counter the threats to pipeline integrity. Pressure testing, in-line inspection and direct assessment methods are used to verify the integrity of a buried pipeline. The Paper Discuses Direct Assessment Methodologies for Hydrocarbon Non Piggable Pipelines. Advantages and Disadvantages of Direct Assessment methodology and DA Protocols. The DA process accomplishes this by utilizing and integrating condition monitoring, effective mitigation, meticulous documentation and timely structured reporting processes. DA is a structured, iterative integrity assessment process through which an operator may be able to assess and evaluate the integrity of a pipeline segment. TIME DEPENDENT THREATS INEVITABLY LED TO NUMEROUS FAILURES WITH A COMMON DEFINING MECHANISM OR SOURCE – CORROSION. This Paper will focus on internal, external and stress corrosion cracking direct assessment along with pre and post assessment, quality assurance, data analysis and integration, and remediation and mitigation activities. This paper will discuss some of the regulatory requirements for Pipeline Integrity Management System.
High-Resolution EMAT as a Diagnostic Tool for Analysis of SCC and Crack-Like Pipelines Defects
Authors: Hilvert Matthias , Beuker Thomas
Published: July 2015

In succession of a research project, the Electro-Magnetic Acoustical Transducer (EMAT) technology could be utilized to generate ultrasound for crack detection in pipelines.

The EMAT technology and smart In-Line Inspection (ILI) tools have been developed to an advanced tool kit for inspection. Today high-resolution EMAT ILI is a diagnostic tool, that provides rich information on pipeline cracking as also the type and condition of external pipeline coatings. A high number of EMAT sensors distributed and acting over the entire pipe circumference enable high-resolution mapping of the pipe wall. Ultrasonic shear-waves at different modes are generated and captured by the transducer arrangement. Acquisition of the ultrasonic reflection and transmission signal in frequency and time domain allows for spectroscopic imaging of the pipe wall. The preferred ultrasonic modes and their associated frequencies can be determined using the corresponding dispersion relation.

This contribution shows how mode selective assessments of the captured ultrasonic spectra can be used for analysis of pipeline defects. Validation of EMAT ILI as an inspection process according to API 1163 is outlined. The established exceptionally high Probability Of Detection (POD) and Identification (POI) is derived from Level I, II and III process verification assessments. Latest developments of tailored EMAT sensor kits for ILI pipeline diagnostics are given.
Internal Corrosion Monitoring System Selection for Cross Country Natural Gas Pipeline: A Case Study of SHPPL
Authors: Vyas Sandeep
Published: July 2015

Reliance Gas Pipelines Limited (RGPL) is currently implementing a gas pipeline project from Shahdol, Madhya Pradesh to Phulpur, Uttar Pradesh for evacuation of gas produced from Coal Bed Methane (CBM) blocks owned by Reliance Industries Ltd. This pipeline will be hooked up with GAIL’s HVJ Pipeline at Phulpur. Over all Pipeline system includes 312 km (approx.) long trunk line, and associated facilities such as Compressor Station at Shahdol, Intermediate Pigging facilities, Metering & Regulating facilities at Phulpur and 12 No. Mainline valve stations.

Gas produced from CBM blocks will be dehydrated within Gas Gathering Station facilities of CBM Project located upstream of pipeline Compressor station at Shahdol. Gas received at pipeline battery limit is dry and non-corrosive gas in nature, Internal corrosion is not expected in normal course of operation, however internal corrosion of the natural gas pipeline can occur when the pipe wall is exposed to moisture and other contaminants either under process upset conditions or under particular operating conditions. Even though internal corrosion is not expected during normal course of operations, to take care of any eventuality, it is proposed to implement Internal Corrosion Monitoring (ICMS) system in this project. ICMS will provide an efficient and reliable means of continuous monitoring internal corrosion.

Internal Corrosion Monitoring (ICMS) system is used as a part of overall integrity management framework; to achieve two objectives viz., verify the corrosive behaviour of gas and to verify the efficacy of applied preventive actions. Philosophy involved in evaluating a suitable CM technique would include :

• Applicable corrosion damage mechanisms, anticipated corrosion rates and probable locations.

• Suitable CM technique and location based on process condition, system corrosivity, water content, pigging facilities, available corrosion allowance, design life, maintenance etc.,

• Measurement frequency.

Some of the Corrosion Monitoring techniques used for pipeline and of relevance are:

• Weight-loss Corrosion Coupons (CC),

• Electrical Resistance probes (ER),

• Linear Polarization Resistance Probe (LPR)

• Ultrasonic Thickness Measurement (UT)

• Sampling Points (SP)

This paper discusses the merits / demerits of these corrosion monitoring techniques, considerations for selecting a specific technique for the Shahdol – Phulpur Gas Pipeline Project and highlights the implementation of the internal corrosion monitoring system.
Latest Generation of ILI Tools for High Resolution Ultrasonic Inspection and Integrity Assessment
Authors: Hennig Thomas , Lokwani Girish
Published: July 2015

Intelligent inline inspections (ILI) are widely used to guarantee a safe operation of pipelines. The inline inspection provides reliable data in an economic way. Historically, magnetic flux leakage technology (MFL) was one of the main technologies applied in pipeline systems. Within the last few years some minor improvements have been introduced in the existing MFL tool fleets, mainly focusing on a higher resolution. Nevertheless, a general restriction based on the physical basics finally limits the sizing capabilities of corrosion defects, esp. for complex shaped defects.

Ultrasonic (UT) is currently the most accurate and reliable In-Line Inspection technology available in the market. These UT ILI Tools record data while travelling through the entire pipeline from Launcher to Receiver. In most cases, the Pipeline Operator does not need to make major adjustments to their pipeline.

The latest generation of UT tools offers high inspection velocities — consequently a reduction of medium flow and loss of production can be avoided. In addition, a very high resolution of transducers in axial and circumferential direction provides excellent input for accurate pressure calculations, e.g. based on Riverbottom profiles or even 3D Finite element modeling.

Using UT as the inspection method greatly increases the confident level of the inspection survey results. This in turn will give Pipeline Operators a greater peace of mind that their true pipeline condition is known thereby reducing unnecessary and costly digs and repairs.

The authors will present some basic background information about ultrasound inspection technologies. State of the art solutions are presented for crack and wall thickness tools.

Combining different technologies in one tool offers additional benefit. One single inspection tool with corrosion and crack transducers enables pipeline operators to operate their system safe with a minimized impact. Finally, the authors will present some special solutions for high pressure deep water applications and multi diameter pipeline systems.
Self Directed Integrity Assessment of Non-Piggable Pipelines
Authors: Khera Ashish , Uprety Rajesh , Baniah Bidyut B.
Published: July 2015

The responsibility for managing an asset safely, efficiently and to optimize productivity lies solely with the pipeline operators. To achieve these objectives, operators are implementing comprehensive pipeline integrity management programs. These programs may be driven by a country’s pipeline regulator or in many cases may be “self-directed” by the pipeline operator especially in countries where pipeline regulators do not exist.

A critical aspect of an operator’s Integrity Management Plan (IMP) is to evaluate the history, limitations and the key threats for each pipeline and accordingly select the most appropriate integrity tool. The guidelines for assessing piggable lines has been well documented but until recently there was not much awareness for assessment of non-piggable pipelines. A lot of these non-piggable pipelines transverse through high consequence areas and usually minimal historic records are available for these lines. To add to the risk factor, usually these lines also lack any baseline assessment.

The US regulators, that is Office of Pipeline Safety had recognized the need for establishment of codes and standards for integrity assessment of all pipelines more than a decade ago. This led to comprehensive mandatory rules, standards and codes for the US pipeline operators to follow regardless of the line being piggable or non-piggable. In India the story has been a bit different. In the past few years, our governing body for development of self-regulatory standards for the Indian oil and gas industry that is Oil Industry Safety Directorate (OISD) recognized a need for development of a standard specifically for integrity assessment of non-piggable pipelines. The standard was formalized and accepted by the Indian Ministry of Petroleum in September 2013 as OISD 233.

OISD 233 standard is based on assessing the time dependent threats of External Corrosion (EC) and Internal Corrosion (IC) through applying the non-intrusive techniques of “Direct Assessment”. The four-step, iterative DA (ECDA, ICDA and SCCDA) process requires the integration of data from available line histories, multiple indirect field surveys, direct examination and the subsequent post assessment of the documented results.

This paper presents the case study where the Indian pipeline operators took a self-initiative and implemented DA programs for prioritizing the integrity assessment of their most critical non-piggable pipelines even before the OISD 233 standard was established. The paper also looks into the relevance of the standard to the events and other case studies following the release of OISD 233.
Online Sulphur Analyzers for Interface Management of BS III/BS IV/BS V Grades in Cross Country Pipelines
Authors: Satya Narayana K. S. L.
Published: July 2015

Over the last few years, the importance of detecting sulphur in petroleum products has increased dramatically. This is related to the necessity of complying with increasingly stringent government regulations and ensuring product quality. Reasons for detection and Monitoring of sulphur in different petroleum products has existed for the last so many years, but detection limits have been reduced dramatically in recent times. The sulphur analyzers for present requirements must now have the ability to detect sulphur from 1 parts per billion to 500 parts per million. This paper discusses about the following aspects:

• Indian Emission standards

• Evolution of BS 3/4/5 grades

• Need for online sulphur analyzers (OSA) in Pipeline industry.

• Detection technology

• Various options available in Online sulphur analyzers

Low Sulphur norms in Petroleum Products have evolved due to the following reasons:

- SO2 formed during combustion of fuels in IC engines damage the engines.

- Acids of SO2 increase rusting of engine parts, piston rings and cylinder walls.

- In environment, SO2 converts to Sulphuric acid by reaction with moisture and harm vegetation, aquatic, animal and human life.

- SO2 also corrodes man made buildings and monuments

This paper also explains about the various types of Online Suplhur analyzers users in HPCL and the issues faced with the same at feld level.
Influence of atomic layer deposition valve temperature on ZrN plasma enhanced atomic layer deposition growth
Authors: Muneshwar Triratna , Cadien Ken
Published: July 2015

Atomic layer deposition (ALD) relies on a sequence of self-limiting surface reactions for thin film growth. The effect of non-ALD side reactions, from insufficient purging between pulses and from precursor self-decomposition, on film growth is well known. In this article, precursor condensation within an ALD valve is described, and the effect of the continuous precursor source from condensate evaporation on ALD growth is discussed. The influence of the ALD valve temperature on growth and electrical resistivity of ZrN plasma enhanced ALD (PEALD) films is reported. Increasing ALD valve temperature from 75 to 95 °C, with other process parameters being identical, decreased both the growth per cycle and electrical resistivity (ρ) of ZrN PEALD films from 0.10 to 0.07 nm/cycle and from 560 to 350 μΩ cm, respectively. Our results show that the non-ALD growth resulting from condensate accumulation is eliminated at valve temperatures close to the pressure corrected boiling point of precursor.
Application of cubic spline models in electron-beam lithography
Authors: Jedidi Nader , Tortai Jean-Hervé , Figueiro Thiago , Schiavone Patrick
Published: July 2015

Proximity effects in electron beam lithography impact feature dimensions and uniformity. These effects are addressed using a mathematical model representing the radial exposure intensity distribution produced by a point source of electrons, commonly named point spread function (PSF). Unfortunately, the multiple Gaussian distribution approximation, the most common PSF model used till now, reaches its limits in terms of efficiency, particularly in case of high atomic number Z substrate materials. A broad family of approximating functions, known as splines, is considered here as a substitute to Gaussian. Through a simulation study using specific test structures, the authors demonstrate the high potential of cubic splines in accurately characterizing high Z substrates PSFs.
A generalized reconstruction framework for unconventional PET systems
Authors: Mathews Aswin John , Li Ke , Komarov Sergey , Wang Qiang , Ravindranath Bosky , O'Sullivan Joseph A. , Tai Yuan‐Chuan
Published: July 2015

Purpose:

Quantitative estimation of the radionuclide activity concentration in positron emission tomography (PET) requires precise modeling of PET physics. The authors are focused on designing unconventional PET geometries for specific applications. This work reports the creation of a generalized reconstruction framework, capable of reconstructing tomographic PET data for systems that use right cuboidal detector elements positioned at arbitrary geometry using a regular Cartesian grid of image voxels.

Methods:

The authors report on a variety of design choices and optimization for the creation of the generalized framework. The image reconstruction algorithm is maximum likelihood‐expectation–maximization. System geometry can be specified using a simple script. Given the geometry, a symmetry seeking algorithm finds existing symmetry in the geometry with respect to the image grid to improve the memory usage/speed. Normalization is approached from a geometry independent perspective. The system matrix is computed using the Siddon's algorithm and subcrystal approach. The program is parallelized through open multiprocessing and message passing interface libraries. A wide variety of systems can be modeled using the framework. This is made possible by modeling the underlying physics and data correction, while generalizing the geometry dependent features.

Results:

Application of the framework for three novel PET systems, each designed for a specific application, is presented to demonstrate the robustness of the framework in modeling PET systems of unconventional geometry. Three PET systems of unconventional geometry are studied. (1) Virtual‐pinhole half‐ring insert integrated into Biograph‐40: although the insert device improves image quality over conventional whole‐body scanner, the image quality varies depending on the position of the insert and the object. (2) Virtual‐pinhole flat‐panel insert integrated into Biograph‐40: preliminary results from an investigation into a modular flat‐panel insert are presented. (3) Plant PET system: a reconfigurable PET system for imaging plants, with resolution of greater than 3.3 mm, is shown. Using the automated symmetry seeking algorithm, the authors achieved a compression ratio of the storage and memory requirement by a factor of approximately 50 for the half‐ring and flat‐panel systems. For plant PET system, the compression ratio is approximately five. The ratio depends on the level of symmetry that exists in different geometries.

Conclusions:

This work brings the field closer to arbitrary geometry reconstruction. A generalized reconstruction framework can be used to validate multiple hypotheses and the effort required to investigate each system is reduced. Memory usage/speed can be improved with certain optimizations.
CT perfusion analysis by nonlinear regression for predicting hemorrhagic transformation in ischemic stroke
Authors: Bennink Edwin , Horsch Alexander D. , Dankbaar Jan Willem , Velthuis Birgitta K. , Viergever Max A. , de Jong Hugo W. A. M.
Published: July 2015

Purpose:

Intravenous thrombolysis can improve clinical outcome in acute ischemic stroke patients but increases the risk of hemorrhagic transformation (HT). Blood–brain barrier damage, which can be quantified by the vascular permeability for contrast agents, is a potential predictor for HT. This study aimed to assess whether this prediction can be improved by measuring vascular permeability using a novel fast nonlinear regression (NLR) method instead of Patlak analysis.

Methods:

From a prospective ischemic stroke multicenter cohort study, 20 patients with HT on follow‐up imaging and 40 patients without HT were selected. The permeability transfer constant Ktrans was measured in three ways; using standard Patlak analysis, Patlak analysis with a fixed offset, and the NLR method. In addition, the permeability‐surface (PS) area product and the conventional perfusion parameters (blood volume, flow, and mean transit time) were measured using the NLR method. Relative values were calculated in two ways, i.e., by dividing the average in the infarct core by the average in the contralateral hemisphere, and by dividing the average in the ipsilateral hemisphere by the average in the contralateral hemisphere. Mann–Whitney U tests and receiver operating characteristic (ROC) analyses were performed to assess the discriminative power of each of the relative parameters.

Results:

Both the infarct‐core and whole‐hemisphere averaged relative Ktrans (rKtrans) values, measured with the NLR method, were significantly higher in the patients who developed HT as compared with those who did not. The rKtrans measured with standard Patlak analysis was not significantly different. The relative PS (rPS), measured with NLR, had the highest discriminative power (P = 0.002). ROC analysis of rPS showed an area under the curve (AUC) of 0.75 (95% confidence interval: 0.62–0.89) and a sensitivity of 0.75 at a specificity of 0.75. The AUCs of the Patlak rKtrans, the Patlak rKtrans with fixed offset, and the NLR rKtrans were 0.58, 0.66, and 0.67, respectively.

Conclusions:

CT perfusion analysis may aid in predicting HT, but standard Patlak analysis did not provide estimates for rKtrans that were significantly higher in the HT group. The rPS, measured in the infarct core with NLR, had superior discriminative power compared with Ktrans measured with either Patlak analysis with a fixed offset or NLR, and conventional perfusion parameters.
A novel synthetic single crystal diamond device for in vivo dosimetry
Authors: Marinelli Marco , Prestopino G. , Tonnetti A. , Verona C. , Verona‐Rinati G. , Falco M. D. , Bagalà P. , Pimpinella M. , Guerra A. S. , De Coste V.
Published: July 2015

Purpose:

Aim of the present work is to evaluate the synthetic single crystal diamond Schottky photodiode developed at the laboratories of “Tor Vergata” University in Rome in a new dosimeter configuration specifically designed for offline wireless in vivo dosimetry (IVD) applications.

Methods:

The new diamond based dosimeter, single crystal diamond detector (SCDD‐iv), consists of a small unwired detector and a small external reading unit that can be connected to commercial electrometers for getting the detector readout after irradiation. Two nominally identical SCDD‐iv dosimeter prototypes were fabricated and tested. A basic dosimetric characterization of detector performances relevant for IVD application was performed under irradiation with 60Co and 6 MV photon beams. Preirradiation procedure, response stability, short and long term reproducibility, leakage charge, fading effect, linearity with dose, dose rate dependence, temperature dependence, and angular response were investigated.

Results:

The SCDD‐iv is simple, with no cables linked to the patient and the readout is immediate. The range of response with dose has been tested from 1 up to 12 Gy; the reading is independent of the accumulated dose and dose rate independent in the range between about 0.5 and 5 Gy/min; its temperature dependence is within 0.5% between 25 and 38 °C, and its directional dependence is within 2% from 0° to 90°. The combined relative standard uncertainty of absorbed dose to water measurements is estimated lower than the tolerance and action level of 5%.

Conclusions:

The reported results indicate the proposed novel offline dosimeter based on a synthetic single crystal diamond Schottky photodiode as a promising candidate for in vivo dosimetry applications with photon beams.
How the thermocline affects the value of the waveguide invariant in a shallow-water waveguide
Authors: Zhao Z. D. , Wu J. R. , Shang E. C.
Published: July 2015

On the basis of the principle of stationary phase, Chuprov [Ocean Acoustics: Current State (Nauka, Moscow, 1982)] proposed a scalar parameter—the waveguide invariant β, to interpret the dispersive properties of underwater acoustic waveguide. It has been found that β may be useful in many applications in underwater acoustics. A reasonable prediction of the value of β is often necessary in such applications. It was known that β has some “canonical” values for waveguides with simple sound speed profiles (SSP). When a thermocline exists, β for refractive modes (with a turning point) is no longer constant and can even change its sign. In this paper, by dividing the SSP into the non-refractive part and the refractive part, a clear explanation of how the value of β is affected by the thermocline is presented. The results show that β can be positive and increase continually from around 1 to +∞; or negative from −∞ to about −3. An analytic criterion of the sign of β is developed. This method can also be used to analyze the value of β for any other kind of SSP.
Killer whale call frequency is similar across the oceans, but varies across sympatric ecotypes
Authors: Filatova Olga A. , Miller Patrick J. O. , Yurk Harald , Samarra Filipa I. P. , Hoyt Erich , Ford John K. B. , Matkin Craig O. , Barrett-Lennard Lance G.
Published: July 2015

Killer whale populations may differ in genetics, morphology, ecology, and behavior. In the North Pacific, two sympatric populations (“resident” and “transient”) specialize on different prey (fish and marine mammals) and retain reproductive isolation. In the eastern North Atlantic, whales from the same populations have been observed feeding on both fish and marine mammals. Fish-eating North Pacific “residents” are more genetically related to eastern North Atlantic killer whales than to sympatric mammal-eating “transients.” In this paper, a comparison of frequency variables in killer whale calls recorded from four North Pacific resident, two North Pacific transient, and two eastern North Atlantic populations is reported to assess which factors drive the large-scale changes in call structure. Both low-frequency and high-frequency components of North Pacific transient killer whale calls have significantly lower frequencies than those of the North Pacific resident and North Atlantic populations. The difference in frequencies could be related to ecological specialization or to the phylogenetic history of these populations. North Pacific transient killer whales may have genetically inherited predisposition toward lower frequencies that may shape their learned repertoires.
Acoustical analysis of Canadian French word-final vowels in varying phonetic contexts
Authors: Law Franzo , Strange Winifred
Published: July 2015

This study analyzed Canadian French (CF) vowels /i y ø e ɛ o u a/ in word-final position. Of particular interest was the stability of /e-ɛ/; although some dialects of French have merged /e-ɛ/ to /e/ in word-final context, this contrast is maintained in CF. The present study investigated the stability of this contrast in various preceding phonetic contexts and in lexical vs morphological contrasts. Results showed that the contrast was maintained by all four speakers, although to varying degrees.
Laboratory Determinants of Repeated-Sprint and Sport-Specific-Technique Ability in World-Class Ice Sledge Hockey Players
Authors: Baumgart Julia Kathrin , Sandbakk Øyvind
Published: July 2015

Purpose:

To investigate on-ice repeated-sprint and sports-specific-technique abilities and the relationships to aerobic and anaerobic off-ice capacities in world-class ice sledge hockey players.

Methods:

Twelve Norwegian national team players performed 8 repeated maximal 30-m sprints and a sports-specific-technique test while upper-body poling on ice, followed by 4 maximal upper-body strength tests and 8-s peak power and 3-min peak aerobic-capacity (VO2peak) tests while ergometer poling.

Results:

The fastest 30-m sprint time was 6.5 ± 0.4 s, the fastest initial 10-m split-time 2.9 ± 0.2 s, and the corresponding power output 212 ± 37 W. Average 30-m time during the 8 repeated sprints was 6.7 ± 0.4 s, and the sprint-time decrement was 4.3% ± 1.8%. Time to execute the sport-specific-technique test was 25.6 ± 2.7 s. Averaged 1-repetition-maximum strength of the 4 exercises correlated with the fastest 30-m sprint time (r = –.77), the fastest initial 10-m split time (r = –.72), the corresponding power output (r = .67), and the average 30-m sprint time (r = –.84) (all P < .05). Peak power of the 8-s ergometer sprint test correlated with the highest initial 10-m power (r = .83, P < .01) and the average 30-m sprint time (r = –.68, P < .05). Average 3-min ergometer power (r = –.86, P < .01) and VO2peak (r = –.67, P < .05) correlated with the sprint-time decrement. All off-ice variables except VO2peak correlated with technique-test time (r = –.58 to .73, all P < .05).

Conclusion:

Maximal strength and power are associated with the ability to sprint fast and rapid execution of a technically complex test, whereas mode-specific endurance capacity is particularly important for maintenance of sprint ability in ice sledge hockey.
Three-Compartment Body Composition in Academy and Senior Rugby League Players
Authors: Till Kevin , Jones Ben , O’Hara John , Barlow Matthew , Brightmore Amy , Lees Matthew , Hind Karen
Published: July 2015

Purpose:

To compare the body size and 3-compartment body composition between academy and senior professional rugby league players using dual-energy X-ray absorptiometry (DXA).

Methods:

Academy (age 18.1 ± 1.1 y, n = 34) and senior (age 26.2 ± 4.6 y, n = 63) rugby league players received 1 total-body DXA scan. Height, body mass, and body-fat percentage alongside total and regional fat mass, lean mass, and bone mineral content (BMC) were compared. Independent t tests with Cohen d effect sizes and multivariate analysis of covariance (MANCOVA), controlling for height and body mass, with partial eta-squared (η2) effect sizes, were used to compare total and regional body composition.

Results:

Senior players were taller (183.2 ± 5.8 vs 179.2 ± 5.7 cm, P = .001, d = 0.70) and heavier (96.5 ± 9.3 vs 86.5 ± 9.0 kg, P < .001, d = 1.09) with lower body-fat percentage (16.3 ± 3.7 vs 18.0 ± 3.7%, P = .032, d = 0.46) than academy players. MANCOVA identified significant overall main effects for total and regional body composition between academy and senior players. Senior players had lower total fat mass (P < .001, η 2 = 0.15), greater total lean mass (P < .001, η 2 = 0.14), and greater total BMC (P = .001, η 2 = 0.12) than academy players. For regional sites, academy players had significantly greater fat mass at the legs (P < .001, η 2 = 0.29) than senior players.

Conclusions:

The lower age, height, body mass, and BMC of academy players suggest that these players are still developing musculoskeletal characteristics. Gradual increases in lean mass and BMC while controlling fat mass is an important consideration for practitioners working with academy rugby league players, especially in the lower body.