bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simulink Pathway for Model-Based Control of Vapor Compression Cycles
Authors: Ngo Anhtuan D. , Cory Joshua R. , Hencey Brandon M. , Patnaik Soumya S.
Published: January 2016

Current and next generation tactical aircraft face daunting thermal challenges that involve reliably maintaining thermal constraints despite large transient loads. Model-based control synthesis has the potential to improve the performance of a vapor compression cycle system during its transient operating condition, driven by intermittent and dynamic thermal loads, when compared to the current heuristic control design technique. However, the excessive labor and expertise necessary to develop models amenable to model-based control design techniques has been an impediment to widespread deployment. This paper demonstrates a Simulink pathway for model-based design via the AFRL Transient Thermal Modeling and Optimization (ATTMO) toolbox. An effective, simple linear quadratic gaussian control design is demonstrated and opens the door for widespread deployment of many advanced control techniques.
Dynamic Affection-Based Motion Control of a Humanoid Robot to Collaborate With Human in Flexible Assembly in Manufacturing
Authors: Rahman S. M. Mizanoor , Wang Yue
Published: January 2016

This article presents a hybrid cell for human-robot collaboration (HRC) in flexible light assembly in manufacturing and investigates the effects of the robot’s dynamic affections on human-robot interactions (HRI) and assembly performance. We develop a one human-one robot hybrid cell using a humanoid robot with affection display ability where the human and the robot collaborate to assemble few parts into a final product. Based on an optimization strategy, the assembly subtasks are optimally allocated between the human and the robot. We determine a computational dynamics model of the robot’s affections for various situations associated with the assembly. Taking inspiration from the affection dynamics, we develop an affection-based motion control strategy for the robot so that the robot can dynamically adjust its affective expressions with task situations. We develop a comprehensive evaluation scheme to evaluate HRI and assembly performance in two different conditions of the robot: (i) the robot displays affections in its face dynamically with assembly task situations, (ii) the robot does not display affection. The results show that the motion control of the robot with dynamic affective expressions produce significantly better HRI and assembly performance than that produced by the motion control of the robot with no affective expression.
Efficient Aeroelastic Energy Harvesting From HVAC Ducts
Authors: Ma Xiaokun , Rahn Christopher D.
Published: January 2016

Piezoelectric energy harvesters can be used to scavenge energy for unattended sensors in heating ventilation and air conditioning (HVAC) ducts. In this paper, an aeroelastic energy harvester using a pinned-pinned beam is designed, modeled, and analyzed. To obtain the desired model, we use nonlinear Euler-Bernoulli beam theory, a linear piezoelectric constitutive law, and nonlinear pressure dynamics. Compared with the traditional cantilever beam used by previous researchers, the pinned-pinned beam has a higher frequency limit cycle and more efficient mode shape, which ensure higher power output at the same strain level. The pinned-pinned boundary condition also self-limits the response amplitude, limiting strain in the piezoelectric beam and premature failure. Simulation results show that the pinned-pinned beam can harvest at least 4 times more average power than a cantilever beam with the same maximum strain.
A Real-Time Brainwave Based Neuro-Feedback System for Cognitive Enhancement
Authors: Abiri Reza , McBride Joseph , Zhao Xiaopeng , Jiang Yang
Published: January 2016

Brain Computer Interface (BCI) provides a pathway to connect the brain to external devices. Neuro-rehabilitation provides advanced means to assist people with movement disorders such as post-stroke patients and those with lost limbs. While much progress has been made in neuro-rehabilitation as assistive devices, few studies had examined mental rehabilitation assisted by BCI such as memory training using neuroenhancement. It should be noted that many patients with physical disabilities also suffer cognitive difficulties. On the other hand, cognitive decline can also be the result of normal aging without brain injury nor diseases. Here, we propose a novel real-time brainwave BCI platform for enhancing human cognitive by designing and employing a personalized neuro-feedback robot. Short-term memory and attention are among the most important cognitive abilities which manifest in many mental diseases. A social robot is integrated into the BCI system to provide feedback based on individual’s brainwaves and memory performance. As a simple scenario of memory task, real-time EEG signals will be monitored during a visual object memory task. Our novel neuro-feedback system has great potential as a neuro-enhancing device for cognitive rehabilitation.
Adaptive Air Fuel Ratio Controls in Presence of Oxygen Sensor Faults
Authors: Jammoussi Hassene , Makki Imad
Published: January 2016

Fault monitoring of the upstream universal exhaust gas oxygen (UEGO) sensor, as mandated by the California air resources board (CARB), is a necessary action to maintain the performance of the operation of the air-fuel ratio (AFR) control system and indicate the need for maintenance when a fault is present which could potentially lead to exceeding the emissions limits. When the UEGO sensor fault is accurately diagnosed, i.e. fault is detected, direction is identified and magnitude is estimated, tuning of the controller gains can be performed accurately with minimal calibration efforts. Presented in this paper is a control strategy that utilizes the type, direction and magnitude of fault detected to adapt the gains of the controller and update the parameters of the Smith predictor (SP) in order to maintain the stability of AFR control loop. The proposed approach has been validated on a vehicle (Mustang V6 3.7L) equipped with ATI No-Hooks rapid prototyping system. Different fault types and magnitudes were tested and the tailpipe emissions were assessed on federal test procedure (FTP) cycles.
Appearance-Based Outdoor Localization Using Group LASSO Regression
Authors: Do Huan N. , Choi Jongeun
Published: January 2016

This paper presents appearance-based localization for an omni-directional camera that builds on a combination of the group Least Absolute Shrinkage and Selection Operator (LASSO) and the extended Kalman filter (EKF). A histogram that represents the population of the Speeded-Up Robust Features (SURF points) is computed for each image, the features of which are selected via the group LASSO regression. The EKF takes the output of the LASSO regression-based first localization as observations for the final localization. The experimental results demonstrate the effectiveness of our approach.
An Iterative Learning Control Approach to Multi-Agent Formations
Authors: Quann Michael , Barton Kira
Published: January 2016

This paper presents an iterative learning control (ILC) based method for trading off both individual and formation tracking for multiple agents with heterogeneous dynamics. The proposed framework provides precise trajectory tracking for systems involving repetitive, cooperative motion. The frequency domain based controller has the capability of being able to shift weighting between the desire for precise formations amongst the agents and precise trajectory tracking for each individual agent. Stability and convergence conditions are shown and the proposed controller is validated through simulations.
Automatic Alignment of Motion Capturing System Markers to a Small Differential Drive Robot’s Position and Heading Angle
Authors: Milutinović Dejan , Casbeer David W.
Published: January 2016

Marker-based motion capturing systems are effective in tracking a robot only if the marker configuration is somehow aligned with the robot’s body. To overcome the manual alignment, in this paper we propose an automatic procedure for a small differential drive ground robot. The procedure requires that the robot travels along an arbitrary curved trajectory. The parameters describing the relative position between the marker configuration and the robot’s body are estimated. Once the parameters are known, they can be used to compute the robot’s center and its heading angle. The effectiveness of the procedure is illustrated by an experiment and the results showing that the accuracy of the robot center position exceeds the accuracy of the motion capturing measurements of the markers’ positions.
Energy Harvesting Efficiency Optimization via Varying the Radius of Curvature of a Piezoelectric THUNDER
Authors: Wang Fengxia , Wu Wei , Alizadehyazdi Vahid , Abedini Amin
Published: January 2016

In this work the energy harvesting performance of a piezoelectric curved energy generator (THUNDER) is studied via experimental and analytical methods. The analytical model of the THUNDER is created based on the linear mechanical electrical constitutive law of the piezoelectric material, the linear elastic constitutive law of the substrate, and the Euler-Bernoulli beam theory. With these linear modal functions, the Rayleigh-Ritz approach was used to then obtain the reduced mechanical electrical coupled modulation equations. The analytical model is verified by the experimental results. Both the experimental and analytical results of the THUNDER’s AC power output, DC power output with Rectifier Bridge and a capacitor, as well as the power output with a microcontroller energy harvesting circuit are reported. Based on the theoretical model, the analytical solution of the DC power is derived in terms of the vibration amplitude, frequency, and the electrical load. To harvest energy from low frequency vibration source by a piezoelectric generator requires the piezoelectric device possessing low resonance frequency and good flexibility. The THin layer UNimorph DrivER (THUNDER) developed by Langley Research Center exhibits high power when it is used as an energy generator and large displacement when it is used as an actuator. Compared to the less flexible PZT, although THUNDER is more difficult to model, THUNDER has better vibration absorption capacity and higher energy recovery efficiency. The effect of the THUNDER’s radius of curvature on energy harvesting efficiency is mainly investigated. We set the THUNDER’s radius of curvature as a dynamic tuning parameter which can tune the piezoelectric generators’ frequency with the source excitation frequency.
Optimal Switching in Anti-Lock Brake Systems of Ground Vehicles Based on Approximate Dynamic Programming
Authors: Sardarmehni Tohid , Heydari Ali
Published: January 2016

Approximate dynamic programming, also known as reinforcement learning, is applied for optimal control of Antilock Brake Systems (ABS) in ground vehicles. As an accurate and control oriented model of the brake system, quarter vehicle model with hydraulic brake system is selected. Due to the switching nature of hydraulic brake system of ABS, an optimal switching solution is generated through minimizing a performance index that penalizes the braking distance and forces the vehicle velocity to go to zero, while preventing wheel lock-ups. Towards this objective, a value iteration algorithm is selected for ‘learning’ the infinite horizon solution. Artificial neural networks, as powerful function approximators, are utilized for approximating the value function. The training is conducted offline using least squares. Once trained, the converged neural network is used for determining optimal decisions for the actuators on the fly. Numerical simulations show that this approach is very promising while having low real-time computational burden, hence, outperforms many existing solutions in the literature.
Robust Attitude Tracking Control for a Quadrotor Based on the Uncertainty and Disturbance Estimator
Authors: Dai Jiguo , Lu Qi , Ren Beibei , Zhong Qing-Chang
Published: January 2016

In this paper, a robust control method based on the uncertainty and disturbance estimator (UDE) is developed to achieve the attitude tracking control for a quadrotor. To facilitate the control design, the coupled terms in the roll, pitch and yaw dynamics are lumped into the uncertainty term and the remained dynamics can be regarded as decoupled subsystems. As a result, for each subsystem, the lumped uncertainty term contains all the coupled terms, uncertainties and disturbances, then the UDE method is applied for the uncertainty compensation. Compared with the existing UDE control works, the introduced filtered tracking error dynamics simplifies the controller design and implementation. Furthermore, the stability analysis of the closed-loop system is established and experimental studies are carried out to illustrate the effectiveness of the developed control method.
Finite Element Modelling of a Generic Rotor-Bearing System and Experimental Validation
Authors: Rehman A. , Ahmed K. S. , Umrani F. A. , Munir B. , Mehboob A. , Ahmad S. M. , Kazmi Z.
Published: January 2016

The design and development of the rotating machinery require a precise identification of its dynamic response for efficient operation and failure prevention. Determination of critical speeds and mode shapes is crucial in this regard. In this paper, a finite element model (FEM) based on the Euler beam theory is developed for investigating the dynamic behavior of flexible rotors. In-house code in Scilab environment, an open source platform, is developed to solve the matrix equation of motion of the rotor-bearing system. The finite element model is validated by the impact hammer test and the dynamic testing performed on the rotors supported on a purpose-built experimental setup. Bearing stiffness is approximated by using the Hertzian contact theory. Obtaining the critical speeds and mode shapes further improves the understanding of dynamic response of rotors. This study paves way towards advanced research in rotordynamics in Faculty of Mechanical Engineering, GIK Institute.
Simultaneous Stabilization of Pitch and Yaw of a Gliding Robotic Fish Using Sliding Mode Control
Authors: Castaño Maria L. , Tan Xiaobo
Published: January 2016

Oceanic sustainability has been a growing global concern due to the increase of potential threats to the integrity of aquatic ecosystems. As a result, more attention has been paid to the monitoring of such environments, leading to the need for autonomous aquatic robots that are capable of monitoring them in an efficient and accurate manner. A gliding robotic fish is a type of underwater robot that stems from combining the energy-efficient underwater glider with the highly maneuverable robotic fish. For accurate trajectory control and precise sensor measurement, stabilization of both pitch and yaw during gliding is of great importance. In this paper we propose a multi-input-multi-output sliding mode controller for simultaneous stabilization of pitch and yaw. In this design, the outputs of both actuators, tail angle and center of gravity, are determined by the errors in both pitch and yaw. The effectiveness of the proposed approach is demonstrated via simulation with comparison to several alternative designs, including a pair of sliding mode controllers dealing with yaw and pitch separately, and a PI controller.
A New Continuum Robot With Crossed Elastic Strips: Extensible Sections With Only One Actuator per Section
Authors: Remirez Andria A. , Webster Robert J.
Published: January 2016

We propose a new kind of continuum robot based on crossed elastic strips. The actuator-specified location of the crossover point controls the lengths of the sections, enabling a wider range of configurations than would be possible with traditional fixed-section-length robots. Push-pull actuation of the crossed strips controls the curvature of the sections. We provide a model that describes the resulting configurations in terms of tangent circular arcs of varying lengths. Experiments with a prototype yield tip positions that agree with model predictions with an average error of 4.6% of the robot’s length.
Modeling of Ionic Polymer-Metal Composite-Enabled Hydrogen Gas Production
Authors: Nagpure Tushar , Chen Zheng
Published: January 2016

Hydrogen extraction using water electrolysis, and microbial biomass conversion are clean and minimum-emission option for renewable energy storage applications. Ionic polymer-metal composite (IPMC) is a category of electro-active polymers that exhibits the property of ion migration under the application of external voltage. This property of IPMC is useful in electrolysis of water (H2O) and produce hydrogen (H2) and oxygen (O2) gases. This paper discusses the electrochemical fundamentals of electrolysis, which provides a linear relationship between the flow rate of hydrogen from electrolysis and the source current. An IPMC electrolyzer circuit model is developed to capture the electrical characteristic of IPMC. The model incorporates nonlinear capacitance, pseudo-capacitance, and a nonlinear resistance defined with a polynomial function. A state-space equation is then obtained to simulate the proposed circuit model for electrolysis. Experimental result shows that the flow-rate of hydrogen production is proportional to the system current and the proposed model validates the step-response of the system. The model prediction error is less than 4.5647%.
Analysis of the Improvement in Accuracy Using Multiple Gyros
Authors: Li Shuyang , Wang Yizhou , Tomizuka Masayoshi
Published: January 2016

The possibility to improve the accuracy of angular velocity estimate by optimally combining multiple individual micro electromechanical systems (MEMS) gyroscopes is analyzed in this paper. Kalman filter (KF) is used to fuse the numerous measurements into a single improved rate estimate. Based on the virtual gyro idea, a revised approach can give an unbiased estimator regardless of the true angular velocity signal. Numerical simulations are performed to demonstrate the desirable performance, reducing the bias drift and noise.
Hybrid System Based Analytical Approach for Optimal Gear Shifting Schedule Design
Authors: He Chaozhe R. , Qin Wubing B. , Ozay Necmiye , Orosz Gábor
Published: January 2016

In this paper, we present a systematic design for gear shifting using a hybrid system approach. The longitudinal motion of the vehicle is regulated by a PI-controller that determines the required axle torque. The gear scheduling problem is modeled as a hybrid system and an optimization-based gear shifting strategy is introduced, which guarantees that the propulsion requirements are delivered while minimizing fuel consumption. The resulting dynamics is proved to be stable theoretically. In a case study, we compare our strategy with a standard approach used in the industry and demonstrate the advantages of our design for class 8 trucks.
Improved Robust Stability Bounds for Sampled Data Time Delay Systems
Authors: Kurudamannil Jubal , Yedavalli Rama
Published: January 2016

This paper presents improved bounds on the perturbations of continuous time plant matrix for robust stability in a sampled data time delay system framework using discrete Lyapunov stability criterion. The proposed improvement on the bounds is achieved using the state transformations as a vehicle. Several state transformation approaches are explored that result in improved bounds. In addition to the sampling period, time delay induced by the controller (in the form static output feedback) in the network is also incorporated in the analysis via state augmentation. The proposed robustness analysis is carried out for various classes of perturbations such as time invariant perturbations, as well as for structured and unstructured perturbations. The proposed methodologies are illustrated with the help of examples along with a discussion of future research directions in this area.
On Improving Battery State of Charge Estimation Using Bulk Force Measurements
Authors: Mohan Shankar , Kim Youngki , Stefanopoulou Anna G.
Published: January 2016

Lithium-ion (Li-ion) batteries undergo physical deformation as their state-of-charge (SOC) changes. The physical deformation causes changes in the pressure (equivalently, force) applied at the end-plates of a constrained battery pack or module. This paper proposes the fusion of bulk force and battery voltage measurements to estimate the SOC in Li-ion battery packs. In this paper, using discrete Linear Quadratic Estimators (dLQEs), the advantage of using force measurements in addition to voltage measurement to improve SOC estimates is quantitatively studied through simulations. It is observed that including force measurements can decrease the mean and standard deviation of SOC estimation error by 50% in some SOC intervals.
Estimation of Location and Orientation From Range Measurements
Authors: Hari Sai Krishna Kanth , Darbha Swaroop
Published: January 2016

Localization is an important required task for enabling vehicle autonomy. Localization entails the determination of the position of the center of mass and orientation of a vehicle from the available measurements. In this paper, we focus on localization by using the range measurements available to a vehicle from the communication of its multiple onboard receivers with roadside beacons. The model proposed for measurement is as follows: the true distance between a receiver and a beacon is at most equal to a predetermined function of the range measurement. The proposed procedure for localization is as follows: Based on the range measurements specific to a receiver from the beacons, a finite LP (linear programming) is proposed to estimate the location of the receiver. The estimate is essentially the Chebychev center of the set of possible locations of the receiver. In the second step, the location estimates of the vehicle are corrected using rigid body motion constraints and the orientation of the rigid body is thus determined. Two numerical examples provided at the end corroborate the procedures developed in this paper.
Rapid Optimization of Multiple-Planetary-Gear Power-Split Hybrid Powertrains
Authors: Zhuang Weichao , Zhang Xiaowu , Peng Huei , Wang Liangmo
Published: January 2016

In recent years, clutches have been used to create multi-mode power-split hybrid electric vehicles (HEVs). Designing an HEV for optimal performance is computationally intensive because of the enormous design space. For single planetary gear (PG) or a double-PG hybrid powertrains, the design with the best fuel economy and launching performance can be identified through exhaustive search. Exhaustive search for a hybrid powertrain with 3PGs is computationally expensive, because of the astronomical number of design candidates. To address the design problem with extremely large design space, a rapid structure optimization method is proposed, which is based on combining different operating modes. A case study compares several different schemes against the results of the exhaustive search. The results show that the proposed mode combination method can identify almost 90% of the best designs. The proposed method shows great potential when applied to hybrid systems with three or more PGs.
Mathematical Modeling of Cardiopulmonary Resuscitation
Authors: Jalali Ali , Berg Robert A. , Nadkarni Vinay M. , Nataraj C.
Published: January 2016

The cardiopulmonary resuscitation procedure (CPR) is a widely used procedure for resuscitating cardiac arrest patients. Many physiological aspects of the procedure are not yet well understood. The first step for understanding and modeling such a complicated procedure is to develop an accurate model of mechanical properties of the chest during CPR. In this paper we propose a novel nonlinear model of the chest that captures the complex behavior of the chest during CPR. The proposed model consists of nonlinear elasticity and nonlinear damping along with frequency dependent hysteresis. We use an optimization technique to estimate the model coefficients for force-compression data collected from careful experiments conducted on swine. The results show excellent agreement.
Hierarchical Design for Connected Cruise Control
Authors: Zhang Linjun , He Chaozhe , Sun Jing , Orosz Gábor
Published: January 2016

In this paper, we propose a hierarchical framework to reduce the design complexity of connected cruise control (CCC), which is used to regulate the longitudinal motion of a vehicle by utilizing wireless vehicle-to-vehicle (V2V) communication. A high-level controller is designed to generate desired motion of the CCC vehicle based on the motion of multiple vehicles ahead. A low-level controller is used to regulate the engine torque and select the appropriate gear to enable the vehicle to track the desired motion. To cope with external disturbances and uncertain physical parameters, we use an adaptive control strategy for the low-level controller. In a case study, we design a specific CCC algorithm by using the presented hierarchical framework. Numerical simulations are used to validate the analytical results and test the system performance.
Parameterized Uncertainty Model Using a Genetic Algorithm With Application to an Electro-Hydraulic Valve Control System
Authors: Kang Zuheng , Kazem Bahaa I. , Fales Roger C.
Published: January 2016

This work proposes a new method of determining a parameterization of an uncertainty model using a genetic algorithm. A genetic algorithm is used in a unique way to solve the non-convex parameterization problem in this work. The methods presented here are demonstrated on an electrohydraulic valve control system problem. This demonstration includes parameterizing an uncertainty class determined from test data for 30 replications of an electrohydraulic flow control valve. The parameterization of the uncertainty is used to analyze the robust stability of a control system for a class of valves.
A Model of Liquid-Drop Spreading for Electrohydrodynamic Jet Printing
Authors: Pannier Christopher P. , Barton Kira , Hoelzle David , Wang Zhi
Published: January 2016

Electrohydrodynamic jet (E-jet) printing is a recent technique for high resolution additive micromanufacturing. With high resolution comes sensitivity to small disturbances, which has kept this technique from reaching its industrial potential. Closed loop control of E-jet printing can overcome these disturbances, but it requires an improved understanding of ink droplet spreading on the substrate and a physical model to predict printed feature locations and geometries from process inputs and disturbances. This manuscript examines a model of ink droplet spreading that uses assumptions that are important to the e-jet process. Our model leverages previous energy balance models that were derived for larger length scale droplets. At the smaller length scale, we find that viscous losses are a significant portion of the energy budget and must be accounted for; this is in contrast to models at length scales two orders of magnitude larger. Our model predicts the droplet height, base radius and contact angle in time from an initial volume and E-jet printing control parameters. The model is validated with published droplet spreading data and new measurements of E-jet printed droplets of diameter 8 μm. The viscous friction calculated in the new model is found to be significant compared to surface energy.
Procedure for Identifying Deformations in Oil and Gas Pipelines Subject to External Forces, Based on Primary ILI Data
Authors: Galvis Fuentes Adriana
Published: January 2016

Oil and gas pipelines that pass through mountainous terrain are subject to an increase in the number of sections affected by the bending deformation’s resulting from external forces, which, when coupled with the construction and operational processes of the systems, cause mechanical damage to the pipelines that has led to containment losses, resulting in operational cost overruns and harmful effects on the environment and on nearby communities, while leaving at high risk the integrity of the petroleum infrastructure.

By using primary data obtained through so-called “smart” in-line inspections or intelligent line inspections (ILIs), the occurrence and magnitude of these deformations and displacements of the pipelines can be determined. With the aid of geotechnical analytical techniques, this information can facilitate the interpretation of the processes that induce these thrusts.

The starting point is the existing knowledge of the characteristics of the installation of the pipelines and of the clearances permitted by the rules and/or reference standards of the industry. The next step consists of comparing that data against the XYZ Data inertial mapping data (obtained through rotations of the XGP geometric tool) in one or more ILI runs, as part of the mechanical analysis procedure.

As a recommended practice, an algorithm is developed for handling the ILI data, showing in parallel the geotechnical zoning data, illustrating it with a study algorithm.
Determining Critical Limits for Creep Velocities of OSBAT Right-of-Way Slope
Authors: Ito William Hideki , Peixoto Vinicius Carvalho
Published: January 2016

Petrobras Transporte S/A – TRANSPETRO – is the largest natural-gas processing company in Brazil and holds the leading position in fuel transportation and logistics in the country. The 14,000-km pipeline network, like other civil transportation infrastructure, crosses a huge variety of geological-geotechnical terrains, including those susceptible to natural hazards. The OSBAT right-of-way, which belongs to TRANSPETRO’s pipeline network, has become the object of study in this paper because some sections along the right-of-way have installed geotechnical instrumentation that indicates creep movements, which have been acting continuously for decades. Due to the importance of the OSBAT pipeline, a bibliographic review to support the development of limits for displacement velocity of slope shearing zones was concluded to assist the department responsible for evaluating when atypical behavior in the historical displacement data occurs. This geotechnical warning, allied with field and in-line inspections, will improve the pipeline risk management program. The limits for inclinometers were established using T-Student statistical analysis from a reading database based on geotechnical field inspections. However, direct correlation with pipe strain was not verified due to small accumulated displacements.
Unprovoked Errors in Geotechnical Monitoring Activities in an RoW
Authors: Montes Edward Francisco Oliveros
Published: January 2016

The Camisea Pipeline Transmission System (PTS), owned by Transportadora de Gas del Perú (TgP) in Peru, consists of two parallel pipelines, a Natural Gas (NG) pipeline and a Liquefied Natural Gas (LNG) pipeline. The NG pipeline is 834 km in length, including a 105 km loop. The LNG pipeline is 557 km in length.

The first 210 km, are defined as having Amazonian geotechnical characteristics, with the presence of sedimentary and metamorphic rocks and a deposit of materials that are easily altered, which are associated with the transition between the Amazon plain and the Andes mountains. The area between km 210 and km 420 is defined as a mountainous sector with materials having better mechanical properties while the section between km 420 and km 730 located in the coastal sector and has erosive processes such as those associated with wind erosion, seismic activity, alluvial deposits, etc.

Due to the variety of geological and geotechnical circumstances of the TgP’s RoW, its PTS incorporates many types of geotechnical monitoring in order to maintain and increase the reliability and integrity of the system. In several sectors not all of the types of monitoring are applicable. Some types of monitoring are: inclinometers and piezometers, aerial surveillance, patrolling, strain gauges (SG), topographic, GIS images (satellite, laser, radar, etc.), culverts, geotechnical optical fiber, accelerometer stations, etc.

This article describes some unprovoked errors that can occur in a complex operation (in terms of logistics, geological, geotechnical and socially), in the development of geotechnical monitoring activities of an RoW. Some of the errors that can occur are:

• Unacceptable photographic record through aerial surveillance;

• Damage to the coating during topographic verification;

• Field reports with incorrect data;

• Incorrect SG records;

• Improper placement of equipment over the pipeline;

• Incorrect records in the GIS database;

• Errors in the topographical record; and

• Inexperience of monitoring staff, etc.

However, occurrence of the above-mentioned errors has been lessened through improved operating procedures. These procedures are based on discussions from the various “lessons learned” sessions, which improved:

• the appropriate recording of conditions identified in the field;

• the labor climate;

• crosswise communication between the different areas; and

• the preventive approach within the operation of the PTS.
Geotechnical Guidelines for the Assessment and Design of Mitigation Measurements for Operating Oil Pipelines
Authors: Alvarez Fabian Rene , Torres Angela Tatiana , Escobar Camilo Marulanda , Aristizabal Jaime Hernan
Published: January 2016

The Colombian petroleum pipelines go through different types of geomorphologies and geological settings; so that the pipeline system is exposed to a variety of processes such as landslides, erosion, scour, sedimentation, and karstification. In order to prevent some of the effects caused by these processes, geotechnical remedial works have been designed and implemented over time. However, in some cases the remedial actions have not exhibited a proper behavior. For this reason, a better understanding of local conditions is required in order to conceive more effective solutions.

This paper provides an overview of a methodological framework for geotechnical assessment and design of mitigation measures based on the evaluation of geological and geomorphological aspects, computational tools, and data processing. Finally, the characteristics of an existing and unsuccessful mitigation civil work are described, and a brief summary of the relevant geotechnical aspects of the proposed design are presented.
Determining the Corrosivity Index of the Electrolyte From the Management of the Weather-Related and Outside Force Threat
Authors: Aristizábal Ceballos Jaime Hernán , Sarmiento Elquier Enrique , Chaves Julián Fernando , Rodríguez Fredy Alberto
Published: January 2016

With regard to hydrocarbon transmission lines, the analysis of susceptibility to external corrosion constitutes a fundamental tool in formulating management plans for the purpose of mitigating such threat by establishing protection barriers that are appropriate for the environmental characteristics identified.

This document presents a perspective from the management of the Weather-related and Outside Force Threat as a contribution to the determination of the corrosivity index for the electrolyte by relating the lithological units of soils with their potential for generating electrochemical oxidation-reduction processes that can lead to the corrosion of buried pipelines.
Importance of Monitoring Third-Party Actions in the Management of the Threat and Risk Posed by Climate and External Forces
Authors: Chamorro Ruíz Mayelis , Chaves Julián Fernando , Aristizábal Ceballos Jaime Hernán , Isabel Montoya María , Henao Padilla María José , Castro Villamarín Nestor
Published: January 2016

The major events involving geotechnical instability that have affected the operation of the hydrocarbon-transfer systems maintained by VIT-Ecopetrol in recent years indicate the importance of managing — in conjunction with the local authorities, the communities, and other stakeholders — policies regarding appropriate land use on and near the rights-of-way (ROWs).

With a view toward ensuring ongoing operations that are in harmony with the environment, VIT-Ecopetrol has been implementing strategies for working with the Colombian government toward the development of scenarios involving shared responsibility for risk management. These scenarios include the harmonization of regional land-use planning with the presence of the hydrocarbon-transport infrastructure; the preparation of emergency plans; and the mitigation of slope-instability events associated with intense deforestation, uncontrolled urban expansion, and other significant changes in land use.

This paper describes the advances that have been made in monitoring the actions of third parties in connection with the management of the threat and risk posed by climate and external forces, based on an analysis of the development of the region and its interaction with areas of geotechnical interest.
ARPEL Guide for the Monitoring of Pipe, Rights of Way and Triggering Agents in the Management of the Integrity of Oil and Gas Pipelines Threatened by Geohazards
Authors: García Hugo , Contreras Maria F.
Published: January 2016

Incidents associated with geohazards involving oil and gas pipelines can be avoided in most cases if there is an adequate program for monitoring pipelines, rights of way and triggering agents aimed at prevention.

Knowledge about how to manage geohazards is currently dispersed in the operators’ experiences, and it is necessary to compile a guide that will facilitate the selection of the appropriate technology for monitoring pipelines, rights of way and triggering agents.

This document explains the development of a project of the Regional Association of Oil, Gas and Biofuels Sector Companies in Latin America and the Caribbean – ARPEL, the deliverable of which will be a practical technical guide for companies operating in Latin America and the Caribbean for which geohazards represent one of the greatest risks to the integrity of oil and gas pipelines.
Validation of Maturity Offset in the Fels Longitudinal Study
Authors: Malina Robert M. , Choh Audrey C. , Czerwinski Stefan A. , Chumlea Wm. Cameron
Published: January 2016

Sex-specific equations for predicting maturity offset, time before or after peak height velocity (PHV), were evaluated in 63 girls and 74 boys from the Fels Longitudinal Study. Serially measured heights (0.1 cm), sitting heights (0.1 cm), weights (0.1 kg), and estimated leg lengths (0.1 cm) from 8 to 18 years were used. Predicted age at PHV (years) was calculated as the difference between chronological age (CA) and maturity offset. Actual age at PHV for each child was derived with a triple logistic model (Bock-Thissen-du Toit). Mean predicted maturity offset was negative and lowest at 8 years and increased linearly with increasing CA. Predicted ages at PHV increased linearly with CA from 8 to 18 years in girls and from 8 to 13 years in boys; predictions varied within relatively narrow limits from 12 to 15 years and then increased to 18 years in boys. Differences between predicted and actual ages at PHV among youth of contrasting maturity status were significant across the age range in both sexes. Dependence of predicted age at PHV upon CA at prediction and on actual age at PHV limits its utility as an indicator of maturity timing and in sport talent programs.
Effects of Sport-Specific Training Intensity on Sleep Patterns and Psychomotor Performance in Adolescent Athletes
Authors: Suppiah Haresh T. , Low Chee Yong , Chia Michael
Published: January 2016

Purpose:

Adolescent student-athletes face time constraints due to athletic and scholastic commitments, resulting in habitually shortened nocturnal sleep durations. However, there is a dearth of research on the effects of sleep debt on student-athlete performance. The study aimed to (i) examine the habitual sleep patterns (actigraphy) of high-level student-athletes during a week of training and academic activities, (ii) ascertain the effects of habitual sleep durations experienced by high-level student-athletes on psychomotor performance, and (iii) examine the impact of sport training intensities on the sleep patterns of high-level student-athletes that participate in low and high intensity sports.

Methods:

Sleep patterns of 29 high-level student-athletes (14.7 ± 1.3 yrs) were monitored over 7 days. A psychomotor vigilance task was administered on weekdays to ascertain the effects of habitual sleep durations.

Results:

Weekend total sleep time was longer than weekdays along with a delay in bedtime, and waketimes. Psychomotor vigilance reaction times on Monday were faster than on Thursday and Friday, with reaction times on Tuesday also faster than on Friday. False starts and lapses were greater on Friday compared with Monday.

Conclusion:

There was a negative impact of sleep debt on student-athletes’ psychomotor performance.
Astroglial networks promote neuronal coordination
Authors: Chever Oana , Dossi Elena , Pannasch Ulrike , Derangeon Mickael , Rouach Nathalie
Published: January 2016

Gap junction–linked astrocytes form a network that coordinates neuronal activity.
CSF-1 delivers a painful signal
Authors: Prabakaran Sudhakaran
Published: January 2016

Injured pain neurons signal microglia by releasing colony-stimulating factor (CSF-1).
Novel Piperazine Arylideneimidazolones Inhibit the AcrAB-TolC Pump in Escherichia coli and Simultaneously Act as Fluorescent Membrane Probes in a Combined Real-Time Influx and Efflux Assay
Authors: Bohnert Jürgen A. , Schuster Sabine , Kern Winfried V. , Karcz Tadeusz , Olejarz Agnieszka , Kaczor Aneta , Handzlik Jadwiga , Kieć-Kononowicz Katarzyna
Published: January 2016

In this study, we tested five compounds belonging to a novel series of piperazine arylideneimidazolones for the ability to inhibit the AcrAB-TolC efflux pump. The biphenylmethylene derivative (BM-19) and the fluorenylmethylene derivative (BM-38) were found to possess the strongest efflux pump inhibitor (EPI) activities in the AcrAB-TolC-overproducing
Escherichia coli
strain 3-AG100, whereas BM-9, BM-27, and BM-36 had no activity at concentrations of up to 50 μM in a Nile red efflux assay. MIC microdilution assays demonstrated that BM-19 at 1/4 MIC (intrinsic MIC, 200 μM) was able to reduce the MICs of levofloxacin, oxacillin, linezolid, and clarithromycin 8-fold. BM-38 at 1/4 MIC (intrinsic MIC, 100 μM) was able to reduce only the MICs of oxacillin and linezolid (2-fold). Both compounds markedly reduced the MIC of rifampin (BM-19, 32-fold; and BM-38, 4-fold), which is suggestive of permeabilization of the outer membrane as an additional mechanism of action. Nitrocefin hydrolysis assays demonstrated that in addition to their EPI activity, both compounds were in fact weak permeabilizers of the outer membrane. Moreover, it was found that BM-19, BM-27, BM-36, and BM-38 acted as near-infrared-emitting fluorescent membrane probes, which allowed for their use in a combined influx and efflux assay and thus for tracking of the transport of an EPI across the outer membrane by an efflux pump in real time. The EPIs BM-38 and BM-19 displayed the most rapid influx of all compounds, whereas BM-27, which did not act as an EPI, showed the slowest influx.
Toward an Evidence-Based Nonclinical Road Map for Evaluating the Efficacy of New Tuberculosis (TB) Drug Regimens: Proceedings of a Critical Path to TB Drug Regimens-National Institute of Allergy and Infectious Diseases
In Vivo
Pharmacology Workshop for TB Drug Development
Authors: Nuermberger Eric , Sizemore Christine , Romero Klaus , Hanna Debra
Published: January 2016

Novel tuberculosis (TB) drug regimens are urgently needed, and their development will be enabled by improved preclinical approaches that more effectively inform and ensure safe selection of clinical candidates and drug combination/regimens. An evidence-based approach for the assessment of nonclinical models supporting TB drug development has been proposed by a joint partnership between the National Institute of Allergy and Infectious Diseases (NIAID) and the Critical Path to TB Drug Regimens (CPTR) Consortium.
Contribution of Population Pharmacokinetics to Dose Optimization of Ganciclovir-Valganciclovir in Solid-Organ Transplant Patients
Authors: Padullés A. , Colom H. , Bestard O. , Melilli E. , Sabé N. , Rigo R. , Niubó J. , Torras J. , Lladó L. , Manito N. , Caldés A. , Cruzado J. M. , Grinyó J. M. , Lloberas N.
Published: January 2016

Treatment of solid-organ transplant (SOT) patients with ganciclovir (GCV)-valganciclovir (VGCV) according to the manufacturer's recommendations may result in over- or underexposure. Bayesian prediction based on a population pharmacokinetics model may optimize GCV-VGCV dosing, achieving the area under the curve (AUC) therapeutic target. We conducted a two-arm, randomized, open-label, 40% superiority trial in adult SOT patients receiving GCV-VGCV as prophylaxis or treatment of cytomegalovirus infection. Group A was treated according to the manufacturer's recommendations. For group B, the dosing was adjusted based on target exposures using a Bayesian prediction model (NONMEM). Fifty-three patients were recruited (27 in group A and 26 in group B). About 88.6% of patients in group B and 22.2% in group A reached target AUC, achieving the 40% superiority margin (
P
< 0.001; 95% confidence interval [CI] difference, 47 to 86%). The time to reach target AUC was significantly longer in group A than in group B (55.9 ± 8.2 versus 15.8 ± 2.3 days,
P
< 0.001). A shorter time to viral clearance was observed in group B than in group A (12.5 versus 17.6 days;
P
= 0.125). The incidences of relapse (group A, 66.67%, and group B, 9.01%) and late-onset infection (group A, 36.7%, and group B, 7.7%) were higher in group A. Neutropenia and anemia were related to GCV overexposure. GCV-VCGV dose adjustment based on a population pharmacokinetics Bayesian prediction model optimizes GCV-VGCV exposure. (This study has been registered at ClinicalTrials.gov under registration no. NCT01446445.)
Novel Aminoglycoside Resistance Transposons and Transposon-Derived Circular Forms Detected in Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates
Authors: Karah Nabil , Dwibedi Chinmay Kumar , Sjöström Karin , Edquist Petra , Johansson Anders , Wai Sun Nyunt , Uhlin Bernt Eric
Published: January 2016

Acinetobacter baumannii
has emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates of
A. baumannii
collected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (
n
= 16) and CC25 (
n
= 7). Resistance to carbapenems was related to
bla
OXA-23
(20 isolates),
bla
OXA-24/40-like
(6 isolates),
bla
OXA-467
(1 isolate), and IS
Aba1-bla
OXA-69
(1 isolate). Ceftazidime resistance was associated with
bla
PER-7
in the CC25 isolates. Two classical point mutations were responsible for resistance to quinolones in all the isolates. Isolates with high levels of resistance to aminoglycosides carried the 16S rRNA methylase
armA
gene. The isolates also carried a variety of genes encoding aminoglycoside-modifying enzymes. Several novel structures involved in aminoglycoside resistance were identified, including Tn
6279
, ΔTn
6279
, Ab-ST3-
aadB
, and different assemblies of Tn
6020
and Tn
aphA6
. Importantly, a number of circular forms related to the IS
26
or IS
Aba125
composite transposons were detected. The frequent occurrence of these circular forms in the populations of several isolates indicates a potential role of these circular forms in the dissemination of antibiotic resistance genes.