bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid State Lighting Life Prediction Using Extended Kalman Filter
Authors: Lall Pradeep , Wei Junchao , Davis Lynn
Published: January 2014

Solid-state lighting (SSL) luminaires containing light emitting diodes (LEDs) have the potential of seeing excessive temperatures when being transported across country or being stored in non-climate controlled warehouses. They are also being used in outdoor applications in desert environments that see little or no humidity but will experience extremely high temperatures during the day. This makes it important to increase our understanding of what effects high temperature exposure for a prolonged period of time will have on the usability and survivability of these devices. The U.S. Department of Energy has made a long term commitment to advance the efficiency, understanding and development of solid-state lighting (SSL) and is making a strong push for the acceptance and use of SSL products to reduce overall energy consumption attributable to lighting.

Traditional light sources “burn out” at end-of-life. For an incandescent bulb, the lamp life is defined by B50 life. However, the LEDs have no filament to “burn”. The LEDs continually degrade and the light output decreases eventually below useful levels causing failure. Presently, the methods described in IES TM-21 are used to predict the L70 life of white LEDs from LM-80 test data. Several failure mechanisms may be active in a LED at a single time causing lumen depreciation. The underlying TM-21 Arrhenius Model may not capture the failure physics in presence of multiple failure mechanisms. Correlation of lumen maintenance with underlying physics of degradation at system-level is needed.

In this paper, a Kalman Filter and Extended Kalman Filters (EKF) have been used to develop a 70% Lumen Maintenance Life Prediction Model for LEDs used in SSL luminaires. This model can be used to calculate acceleration factors, evaluate failure-probability and identify ALT methodologies for reducing test time. Nine-thousand hour LM-80 test data for various LEDs have been used for model development. System state has been described in state space form using the measurement of the feature vector, velocity of the feature vector change and the acceleration of the feature vector change. System state at each future time has been computed based on the state space at preceding time step, system dynamics matrix, control vector, control matrix, measurement matrix, measured vector, process noise and measurement noise. The future state of the lumen depreciation has been estimated based on a second order Kalman Filter model and a Bayesian Framework. The measured state variable has been related to the underlying damage using physics-based models. Life prediction of L70 life for the LEDs used in SSL luminaires from KF and EKF based models have been compared with the TM-21 model predictions and experimental data.
Dynamic Analysis of Thin Glass Under Ball Drop Impact With New Metrics
Authors: Xue Liang , Coble Claire R. , Lee Hohyung , Yu Da , Chaparala Satish , Park Seungbae
Published: January 2014

Response of brittle plate to impact loads has been the subject of many research studies [1–7]. Specifically, glass presents a wide variety of applications in daily life, and helps to protect the displays of smartphones, tablets, PCs, and TVs from everyday wear and tear. Therefore, the necessity of glass to resist scratches, drop impacts, and bumps from everyday use leads to the importance of investigation of the glass response under dynamic impact loading. The ball drop test has been applied in the past, specifying an energy threshold as a prediction metric. Use of energy as the key parameter in impact testing is limited, since it does not account for the time spent in contact during the impact event. This study attempts to establish a reliable metric for impact testing based on a momentum change threshold. The deformation and the strain of the glass will be obtained by the Digital Image Correlation (DIC) system, while the rebound velocity will be measured with the high speed cameras. The global and local measurements are conducted to verify the accuracy of the experimental results. Finally, the FEA model is developed using ANSYS/LS-DYNA to provide a comprehensive understanding of the dynamic response of the glass. Excellent correlation in deflection is obtained between the measurements and predictions.
An Experimental and Numerical Study of the Behavior of the Thin Glass Edge Under Ball Drop Impact
Authors: Xue Liang , Liu Dapeng , Lee Hohyung , Yu Da , Chaparala Satish , Park Seungbae
Published: January 2014

Glass is widely used as cover glass to protect the smartphones, tablets, PCs, and TVs from everyday wear and tear nowadays. There has been an increasing effort to understand the global behavior of glass substrate under impact, but the behavior of the edge for the thin glass has rarely been touched. In this study, the dynamic response of the glass edge when impacted with 1.75-inch steel ball from different heights (different potential energy) and different angles is studied. High-speed camera is applied for the direct visualization of the whole impact process. The Digital Image Correlation (DIC) method enables to obtain displacements (in-plane displacement and out-of-plane displacement) of the glass during the impact process. The failure mode for the edge impact is found to be predominantly buckling. The tape used in this study decreases wave propagation from the impact location. In addition, the FEA model of edge impact test is developed in ANSYS/LS-DYNA™.
Combining Computational Fluid Dynamics (CFD) and Flow Network Modeling (FNM) for Design of a Multi-Chip Module (MCM) Cold Plate
Authors: Fernandes John , Ghalambor Saeed , Docca Akhil , Aldham Chris , Agonafer Dereje , Chenelly Evan , Chan Benson , Ellsworth Michael
Published: January 2014

The objective of the study is to improve on performance of the current liquid cooling solution for a Multi-Chip Module (MCM) through design of a chip-scale cold plate with quick and accurate thermal analysis. This can be achieved through application of Flow Network Modeling (FNM) and Computational Fluid Dynamics (CFD) in an interactive manner. Thermal analysis of the baseline cold plate design is performed using CFD to determine initial improvement in performance as compared to the original solution, in terms of thermal resistance and pumping power. Fluid flow through the solution is modeled using FNM and verified with results from the CFD analysis. In addition, CFD is employed to generate flow impedance curves of non-standard components within the cold plate, which are used as input for the Hardy Cross method in FNM. Using the verified flow network model, design parameters of different components in the cold plate are modified to promote uniform flow distribution to each active region in the chip-scale solution. Analysis of the resultant design using CFD determines additional improvement in performance over the original solution, if available. Thus, through complementary application of FNM and CFD, a robust cold plate can be designed without requiring expensive fabrication of prototypes and with minimal computational time and resources.
Modeling and Optimization of Small Thermoelectric Generators for Low-Power Electronics
Authors: Dunham Marc T. , Barako Michael T. , LeBlanc Saniya , Asheghi-Roudheni Mehdi , Chen Baoxing , Goodson Kenneth
Published: January 2014

Compact thermoelectric generators operating with small temperature differences can be used to power autonomous circuitry and low-power electronics. This work presents an analysis of potential design optimizations for such devices, also called μTEGs. The analysis considers the effects of external thermal resistances, fill factor, ZT values, and the choice of insulating filler material on the thermoelectric performance. Many of the trends are strongly related to the ratio of internal to external thermal resistance, which determines the proportion of the total temperature drop realized across the active region of the thermoelectric. The results of this analysis provide a framework for thermal optimization of thermoelectric devices designed for small-scale heat to electricity conversion. Further, external thermal resistances are shown to be a dominant factor in performance for compact devices.
Estimation Method of Temperature Distribution and Energy Saving Technology of Air Conditioner in Data Center
Authors: Sano Kentaro , Shimizu Hayato , Kondo Yoshihiro , Fujimoto Takayuki
Published: January 2014

Reducing the energy consumption of a data center has recently become important because the data center market is rapidly expanding. We developed the “IT-facility linkage system” to deal with this energy saving requirement. This system reduces the amount of energy consumed in a data center by linking two systems, one is the optimized server load allocation system and the other is the air conditioning optimization control system. One of the key technologies of the “IT-facility linkage system” is the precise prediction of the server inlet temperature. If we can comprehend the future temperature distributions, we can reduce the amount of energy consumed in a data center by consolidating the IT load to the more effectively cooled servers. We carried out computational thermal fluid dynamics to predict server inlet temperatures and evaluated the prediction precision by comparing the measured temperature data for this paper. As a result, we found out that when we use a detailed rack model and reproduce the characteristic air flow of a data center such as the recirculation, we can precisely predict the server inlet temperature to within less than one degree.
CFD Modeling of Indirect/Direct Evaporative Cooling Unit for Modular Data Center Applications
Authors: Gebrehiwot Betsegaw , Dhiman Nikhil , Rajagopalan Kasturi , Agonafer Dereje , Kannan Naveen , Hoverson James , Kaler Mike
Published: January 2014

An information technology (IT) container needs to be supplied with cold air to cool IT equipment housed in it. The type of cooling system to be used depends on many factors including geographical location of the modular data center. Data centers located in regions where the climate is cold benefit from use of air-side economization (ASE) and those located in hot and dry climate benefit from use of direct and/or indirect evaporative cooling (DIEC) systems. In terms of energy saving, ASE, direct evaporative cooling (DEC) system, and indirect evaporative (IEC) systems are better than compressor based cooling systems such as computer room air conditioning (CRAC) units and air handling units (AHU).

In this study, an existing DIEC unit which can also be operated in ASE mode is modeled in a computational fluid dynamics (CFD) tool. The cooling unit is intended to be used for supplying cold air to a containerized data center with specified volume flow rate, dry-bulb temperature and relative humidity. The CFD model is compared with published data of the cooling unit to see how well the CFD model represents the actual system and few design improvement ideas are tested by modifying the CFD model and running simulations. Results show that supplying air horizontally or as a downdraft to an IT container has negligible effect on the overall system. Results also show that orientation of dampers and placement of blanking panels inside the mixing chamber could affect the lifespan of air filters.
Assessment of Lumen Degradation and Remaining Life of LEDs Using Particle Filter
Authors: Lall Pradeep , Zhang Hao , Davis Lynn
Published: January 2014

The development of light-emitting diode (LED) technology has resulted in widespread solid state lighting use in consumer and industrial applications. Previous researchers have shown that LEDs from the same manufacturer and operating under same use-condition may have significantly different degradation behavior. Applications of LEDs to safety critical and harsh environment applications necessitate the characterization of failure mechanisms and modes. This paper focuses on a prognostic health management (PHM) method based on the measurement of forward voltage and forward current of bare LED under harsh environment. In this paper experiments have been done on single LEDs subjected to combined temperature-humidity environment of 85°C, 85% relative humidity. Pulse width modulation (PWM) control method has been employed to drive the bare LED in order to reduce the heat effect caused by forward current and high frequency (300Hz). A data acquisition system has been used to measure the peak forward voltage and forward current. Test to failure (luminous flux drops to 70 percent) data has been measured to study the effects of high temperature and humid environment loadings on the bare LEDs. A solid state cooling method with a peltier cooler has been used to control the temperature of the LED in the integrating sphere when taking the measurement of luminous flux. The shift of forward voltage forward current curve and lumen degradation has been recorded to help build the failure model and predict the remaining useful life. Particle filter has been employed to assess the remaining useful life (RUL) of the bare LED. Model predictions of RUL have been correlated with experimental data. Results show that prediction of remaining useful life of LEDs, made by the particle filter model works with acceptable error-bounds. The presented method can be employed to predict the failure of LED caused by thermal and humid stresses.
Experimental Observation of the Effect of Crystallographic Orientation on Mechanical Behavior of Single Crystal Cu6Sn5 Intermetallic
Authors: Choudhury Soud Farhan , Ladani Leila
Published: January 2014

Solder joints in electronic packages and devices serve as mechanical and electrical connections as well as thermal paths for heat dissipation. Due to the miniaturization of electronic packaging, nowadays solder joints contain large volume fraction of IMCs. It has been observed that solder joint strength is controlled largely by intermetallic strength at higher strain rate. Macroscopic properties such as tensile and shear strength, creep, ductility depend on Intermetallic layer’s properties of solder joints. This study is carried out to determine elastic-plastic properties of Cu6Sn5 intermetallic in Sn-3.5Ag/Cu system with reflow soldering by nanoindentation. Elastic properties such as elastic modulus and hardness were determined from the load-depth curve. A widely used reverse analysis model described by Dao et al. [1] was considered to extract plastic properties such as yield strength and strain hardening exponent using nanoindentation results. Anisotropy of Cu6Sn5 was taken into consideration to see if that has any effect on the mechanical properties. Our study considered crystallographic grain orientation along normal to the growth axis of Cu6Sn5 IMC which was extracted using Electron backscatter diffraction (EBSD) mapping. Statistically indistinguishable properties were observed for Cu6Sn5 IMC. Average elastic-plastic properties of Cu6Sn5 were than compared with already published results in literatures.
Residual Stress in Silicon Caused by Cu-Sn Wafer-Level Packaging
Authors: Taklo Maaike M. V. , Vardøy Astrid-Sofie , De Wolf Ingrid , Simons Veerle , van de Wiel H. J. , van der Waal Adri , Lapadatu Adriana , Martinsen Stian , Wunderle Bernhard
Published: January 2014

The level of stress in silicon as a result of applying Cu-Sn SLID wafer level bonding to hermetically encapsulate a high-performance infrared bolometer device was studied. Transistors are present in the read out integrated circuit (ROIC) of the device and some are located below the bond frame. Test vehicles were assembled using Cu-Sn SLID bonding and micro-Raman spectroscopy was applied on cross sectioned samples to measure stress in the silicon near the bond frame. The test vehicles contained cavities and the bulging of the structures was studied using white light interferometry. The test vehicles were thermally stressed to study possible effects of the treatments on the level of stress in the silicon. Finite element modeling was performed to support the understanding of the various observations. The measurements indicated levels of stress in the silicon that can affect transistors in regions up to 15 μm below the bond frame. The observed levels of stress corresponded well with the performed modeling. However, no noticeable effect was found for the ROIC used in this work. The specific technology used for the fabrication of the ROIC of a MEMS device is thus decisive. The level of stress did not appear to change as a result of the imposed thermal stress. The level of stress caused by the bond frame can be expected to stay constant throughout the lifetime of a device.
Effect of Hydrogen on the Mechanical Properties of Silicon Crystal Surface
Authors: Izumi Hayato , Mukaiyama Ryota , Shishido Nobuyuki , Kamiya Shoji
Published: January 2014

This paper reports the mechanical properties of single crystal silicon surface changed with hydrogen atoms trapped by underwater boiling treatment. Nanoindentaion test using a Berkovich indenter in six different indentation loads ranging from 100 μN to 1000 μN was conducted to obtain the load-displacement curve. The energy dissipated in plastic deformation, i.e. plasticity energy, during indentation on silicon wafers with different carrier concentration (undoped, lightly and heavily boron doped silicon) were compared. After boiling treatment, increment in the plasticity energy was observed on silicon containing boron. This result suggests that hydrogen atoms trapped inside silicon enhanced dislocation mobility leading to larger plastic deformation.
Neotectonics in Hydrocarbon Transportation Lines Corridors: The Need of a Detailed Study
Authors: Amórtegui José Vicente
Published: January 2014

The Colombian pipeline network is exposed to the permanent activity of geological processes that happen in the country, due to the location of the country in the north-western corner of the South American plate — where it is interrelated to the Nazca and Caribbean plates —, the Andean zone is subject to compression strains that cause the uplifting of the mountain ranges and with it their slopes, which eases the instability processes. On the other hand, since the country is located in the inter-tropic zone of the planet, where the rock deterioration processes are harsher, landslides are more frequent, this together with the condition of strains, makes instability something fairly common.

Evidence on pipelines for hydrocarbon transport is obtained from the fault activity, like this:

The Santiago–El Porvenir oil pipeline, that rises from the plains to the mountain range, in December of 1991 a sudden linear landslide of the pipe was evidenced in the Santiago field (flat zone in the plains, south of Maní, Casanare), the position of the topographic control markers of the line was verified and a terrain shortening of 22.5cm was found in the markers located both sides of the Yopal fault, for this reason the pipe had moved from the area into the launching trap of Santiago, located 60km away from the trace of the fault.

In the Medellín–Cartago pipeline, in the crossing above the Cauca river, in the area of La Felisa, there is a 2.57m misalignment, in relation to the construction location, where the towers were aligned with the direction of the pipe, around 25 years ago. Nowadays the curve in the pipe suspended from the bridge cables can be observed, which, given the length of the bridge of around 200m doesn’t affect the mechanical conditions of the pipe. Along the Cauca river passes one of the geological faults of the Romeral system. (figure 5).

Due to the tracing of the initial pipes of the Cusiana Field, in the late 90s of the past century, a shortening of more than 2m of distance was detected between the geodesic spots of the National Geodesic Network, Taura and Mena, that are found beside the Guaicaramo faults system, these spots were built in the early 50s and located with first order geodesic precision procedures.
Protection Works of Crossings River in the Camisea Pipeline Transport System (STD)
Authors: Tupayachi Beisaga José Luis , Hernández Chaupis Emilio A.
Published: January 2014

The experience gained during the operation and maintenance stages of the Camisea pipeline transportation system (STD) in Peru, crossing from the Tropical jungle in the Cusco region to the coast, in Lima city, has enabled us to develop and apply techniques in construction and maintenance works focused on controlling of the vertical undermining of riverbeds and the erosion of margins at river crossings and creeks crossed by the pipeline carrying NG and NGL. According to the above, a technical assessment study was conducted of the crosses rivers and creeks that have high priority of the Camisea pipeline path, comprising — among other disciplines — hydraulic and undermining analysis, as well as an hydrologic and geo-morphological evaluation and other issues regarding general geology and geo-techniques at each crossing site.

A work program was developed using the information obtained in the three sectors travelled by the (STD) in order to develop and complement works at the crossings of rivers and valleys aiming to protect the integrity of the pipeline from erosion produced by major and extraordinary floods in riverbeds and alluvial slides in narrow valleys, by means of confinement and sedimentation works.

The jobs performed in rainforest, mountain and coastal terrain crossed by the pipeline considered different river morphology types — being the most common the straight, gravel braided and curved river travels — and regimes in both flow speed and width of the riverbed.

From the topographic follow-up and monitoring stage on — before and after the rain season — at crossings beneath the riverbeds, it was determined that the deterioration process affecting the crossing stripe corresponds to erosion consisting in the alteration of the watercourse banks that affects the piping foundations.

The works are completed considering the type of resources available at the site of the river crossing — i. e., the engineering is particular to each sector, and designing is performed upon available materials in the area.

The most utilized works at river and creeks crossings on the Camisea piping system are as follows: i) protection of riverbeds and creeks slopes using gabion mesh and pads; ii) sedimentation systems on gabion mesh; iii) Energy dissipation devices at creeks crossings; iv) rip-rap–type armoring of riverbeds; v) confinement check dams; vi) marginal protection dikes; vii) marginal protection rock fill dams; viii) protection and sedimentation breakwaters, among others.
Landslide Followed by a Leak at the Patagonian Andes, Argentina
Authors: Carnicero Martin , Hryciuk Pedro
Published: January 2014

Gasoducto del Pacífico is a pipeline that carries natural gas from southern Argentina to Chile, through the Patagonian Andes. During previous years of operation only minor sign of soil movement were registered by the monitoring program, taking the form of ditch settlements. However, on September, 2005 a landslide took place producing a gas leak, at a segment that was previously characterized as a non-critical one. An initial office review of available information and site pictures would not yield a clear reason of land movement initiation given the terrain mild slope. Actions were taken aiming at three different time frames. Immediate remedial actions were taken such as ditch opening to free stresses and replacement of buckled pipeline. Integrity specialist flew to the site to conduct geological survey and a stress analysis was conducted at a lab, allowing to asses and manage present risk before transportation began. Mid-term solutions were implemented as the ditch remained open until the next summer season, when access to the site was guaranteed. Finally, two new river crossings were constructed to mitigate this natural hazard permanently. Lessons from this incident revealed design aspects that need to be reconsidered to assure mountain pipelines integrity.
Technological Platform for the Monitoring of Natural Hazards in the OCENSA Pipeline System
Authors: García Hugo , Corrales Julián , Colonia Juan Diego , Jaramillo Guillermo
Published: January 2014

The OCENSA pipeline system crosses two mountain ranges with diverse geological origins, as well as 288 river crossings and areas with diverse climates and seismic activity. To monitor these natural hazards, the OCENSA pipeline has implemented its own rain gauge network, which together with the satellite information service, electrical radar and seismic information, are integrated into a web platform that receives information in real time. This paper presents the equations that define the thresholds for rains that trigger landslides and the relationship between earthquakes and consequent probability of material affectation.
Analysis of Undermining and Lateral Erosion to Maximize Designs of River Crossing of Pipelines
Authors: Avendaño Jorge Alejandro , García López Manuel
Published: January 2014

Erosion of the riverbank is one of the main issues that affect the oil lines in the world. Several studies, developed by the authors of this paper, in different basins of the country, identified the most common processes of instability and erosion of riverbanks in the affected areas. Concerning the characteristics of the problem, several alternatives have been considered to reduce the erosion rate and give priority to the mitigation of geomorphic processes and the stability of agricultural soils adjacent to the riverbank. The general goal of this article is to present several case studies and analytical tools that will allow estimating and evaluating the processes of lateral migration and undermining of the river-bed in the design of river crossing and outline of oil pipelines, in general. The experience of these authors in regards to erosion issues has allowed identifying the contribution of deposits suspended from the banks and that can be controlled combining stabilizing techniques according to the affected area. Usually, the lower half of the slope that is exposed to high shearing forces has to be protected through the use of strong and durable materials while the rest of the slope can be protected with native vegetation. Finally, the analytical alternatives presented by mathematical modeling are employed to predict hydraulic and mechanical effects from which can be exposed to margins in the construction stage and operation of the oil pipeline.
Monitoring and Control System in an Area of Geotechnical Risk Unstable in the Camisea Gas Transport System
Authors: Velásquez Martinez Fernando A. , Acero Carlos Romero
Published: January 2014

The experience gained during the operation and maintenance activities on the Camisea Pipeline Gas Transport System (SDT) owned by TGP in Peru — which goes from the Amazon rainforest in the region of Cusco to the Pacific coast near Lima, along 729 Km — has led to the evolution and the optimization of the design, construction and maintenance processes regarding works focused on the stabilization of the slopes along the right of way of the pipeline carrying natural gas and natural gas liquid.

This section of the right of way is 95 km long and crosses tropical mountains in the Amazon rainforest, in a transitional area between the Manugaly valley and the basin top boundary.

It was noticed since 2005 that the right of way had being affected by a land slide consisting of a horizontal crack in the ground, between both pipelines and along them. So, after number of in-site inspections, the team concluded that the area was being affected by a large ground removal event.

As a consequence, traces of geotechnical instability were found on the right side of the right of way, consisting of stress cracks, transverse settlements and leaks. All of those were affecting the stability conditions of the ground. From the annual in-site follow-up, monitoring and geotechnical testing, the team established that this process affecting the right of way was caused by a large mass removal process directly related to the increase of the imbalance rate of an old colluvial deposit below the entire area, triggered by the heavy rainfall in the area — ca. 3 500 mm a year, mainly between October and April.

It is to be mentioned that the axis of the NG and NGL pipelines is located on the top of this colluvial deposit, which is susceptible to landslides. This is noticeable because of cracks present in the place. Local geomorphology and heavy deforestation — caused by locals — triggers an increase of the rainfall water filtration rate into the ground, thus speeding up the slide processes. Piezometers installed in the area showed high levels of the local water table. Movement readings are: top length: 70 m; length: 250 m; width: 150 m.

Criteria for the construction of landslide mitigation structures in the pipeline área are being established based on a permanent land survey monitoring system — including inclinometers, piezometers and strain-gages — as this is a large regional movement. This control action allowed the operation to continue free of damages to the pipelines and under controlled costs.
Integrity Management Program for Geo-Hazards in the OCENSA Pipeline System
Authors: García Hugo , Nieves Carlos , Colonia Juan Diego
Published: January 2014

Oil pipelines systems for hydrocarbons transportation are linear projects that can reach great lengths. For this reason, theirs paths may cross different geological formations, soil types, navigable or torrential waters; and they may face geotechnical and hydrological instability problems such as creeping slopes, geological faults, landslides, scour and differential settling which causes different relative movements between the soil and the pipeline. The OCENSA (Oleoducto Central S.A) 30″ and 36″ diameter system was built in 1997 to transport crude oil from the eastern foothills of the Andes to the Caribbean Coast along some 830 km of the Eastern Andes mountains range and the spurs of the central Andes mountains range of Colombia: it was a major challenge to secure the integrity of the pipeline in the face of natural events.
A Rating Method for Assessment Risk at River Crossings
Authors: Carnicero Martin
Published: January 2014

Detailed studies performed to design works at river crossings provide all the information needed to asses hydro technical hazards. TGN performed such studies for critical rivers as part of its Integrity Management Program. By monitoring performance of remediation works, experience was built throughout 10 years comprising different hydrological years. This was the base for the development of a simpler methodology aimed at assessing risk using information that can be readily available in regions such as Latin America where the existence of gaging stations and historic records at most rivers are not common. The method is based in river geomorphology, summarized with two parameters: area of drainage basin area and river slope at the crossing. They characterized the type of problems that can be expected and they can be estimated from topographic maps or digital terrain models available from the internet. The rating method follows a basic structure consisting in the product of two factors: causes and consequences. Causes include: bank erosion, river bed scour, meanders and river diversion along the right of way. Then, increasing factors are applied accounting for deforestation, land use and the occurrence of debris flows; decreasing factors consider proper remediation works, design and construction aspects implemented during construction. Finally, consequences are focused at loss of human life, impact on the environment, and interruption of fluid transport. This method is aimed to be performed by a pipeline operator that can have a good feeling of problems related to rivers, without having the technical knowledge of a specialized consultant. While rating, subjective judgment still plays an important role. However, this methodology provides a systematic approach that includes all aspects affecting river crossings, allows for prioritizing works based on rates and, as new rivers are included from new watersheds, it can be improved as prediction and characterization tool.
Pipeline Integrity Assessment and Mitigation Techniques in Unstable Soil Conditions Based on Comparison of In Line Inspection Results
Authors: Contreras Maria F. , Vergara Carlos , Pereira Mauricio , Colonia Juan Diego , García Hugo
Published: January 2014

The Andes Mountains, rich in geographical features and diversity, poses a significant threat to the integrity of oil and gas pipelines due to geohazards. Land movement and unstable soil conditions can trigger changes in the original trajectory of the pipeline resulting in undesired bending strain which can result on failure of the facility.

OCENSA – Oleoducto Central S.A. from Colombia assesses the pipeline condition in geotechnical unstable places by comparison of In Line inspection results taking into account pipeline movements and bending strains changes along the zone of study. Bending strains in the pipe are compared against allowable values and emergency values which constitute the criteria to execute mitigation and/or remediation activities that must be done in order to maintain the pipe integrity. To project the pipeline behavior in time, 3D finite element models are developed, allowing the programming of future activities. This paper presents results obtained in a study case to show how pipeline is assessed and how different mitigation activities are developed. Mitigation Techniques such as stress relief procedures and EPS (Expanded Poly-Styrene) blocks incorporations are explained. These techniques are executed in order to reduce the pipe response due to soil displacements during landslide events and creeping slopes, with the final scope of assuring a safe operation.
Determination of the Separation of Diverter Berms for Erosion Control
Authors: Pineda Carlos Eduardo Rodríguez , Rodríguez Paula Andrea , Gómez Juan Sebastián Gutiérrez
Published: January 2014

Diverter berms are structures that are intended to control erosion by means of the reduction of the dragging forces due to runoff. In a hillside, as the slope and length increases, the towing capacity of the runoff increases; diverter berms aim to reduce the flow length and with this the water potential erosion.

In Colombia is common to determine the separation of diverter berms based in the graphics presented in the NIO 0802 standard (Ecopetrol, 2001), in which separation is function of the slope of the hillside, the type of soil and the rainfall intensity.

In this paper the equations proposed by Morgan (1995) and Mirtskhoulava (2001) are applied to determine the separation of diverter berms based on the maximum non-eroding velocity, the discharge flow, the surface roughness and the slope steepness.

In order to compare the results of the application of the Morgan (1995) and Mirtskhoulava (2001) models, with those curves of the NIO 0802 standard (Ecopetrol, 2001), an application was made to the right-of-way for the Medellín-Cartago pipeline, along the called Sinifana variant. The information regarding topography, soils and coverage was provided by Civil and Tech SAS.
Susceptibility to Erosion of Pipeline Rights-of-Way in Tropical Soils: Case of a Brazilian Pipeline
Authors: Russo Wanderley Camargo , dos Santos Filho Alcindo Pereira , da Silveira Filho Celso Rodrigues , dos Santos Amaral Cláudio , Sales Maurício Martines , Vargas Carlos Alberto Lauro , Romão Patrícia de Araújo , Nascimento Diego Tarley Ferreira
Published: January 2014

TRANSPETRO is responsible, among other activities, by operation and maintenance of pipelines throughout Brazil. Particularly in the Midwest region the company operates the OSBRA pipeline, which moves about 8.7 Mm3/years of fuel and covers approximately 1,000 km long, predominantly in tropical soils. Erosive processes are significant and constitute the main geotechnical occurrence in OSBRA pipelines rights-of-way. In order to identify the susceptibility to erosion of the area close to the pipelines were developed basic thematic maps, that overlaid will help in identifying homogeneous zones in terms of existing material susceptibility. The mapping is being accompanied by an extensive endeavor of field inspections along the pipeline rights-of-way, that comprised geotechnical investigations, verifying the conditions of use and soil management, the conservation status of existing drainage works and geotechnical characterization of soil samples of major geological formations, including erodibility tests. The methodology is being developed in ArcGIS frame, starting from the morphometric analysis and the use of Digital Elevation Models (DEM), aiming to understanding superficial flow conditions (acceleration and concentration) and consequent soil loss. The modeling results will be compared with historical occurrences erosive 15 (fifteen) years of pipeline operation, seeking for an adherence on various geological, topographical and meteorological tested. The methodology will improve further procedures for identifying potential erosions in tropical soils and will allow to anticipating preventive maintenance in the most susceptible locals the pipeline rights-of-way, suggesting mitigation measures best suited for each type of potential erosive mechanism.
Emergency due to Rain Event on OSPAR Pipeline Right-of-Way: Lessons Learnt From the Rapid Approach in March, 2011
Authors: Oliveira Hudson Régis , de Paula Henrique Xavier
Published: January 2014

Nowadays, natural disasters have become much frequently in Brazil, having as result serious consequences such as social, economic and environmental damages and losses.

The aim of this paper is evaluate the actions provided by TRANSPETRO in emergency span occurred in OSPAR right-of-way due to intense and heavy rains that occurred in March 2011 in the Serra do Mar Hills, in Parana State, southern Brazil.

The geotechnical phenomenon affected three pipelines:

• OSPAR Oil Pipeline, which is responsible for supplying the Presidente Getulio Vargas Refinery - REPAR with crude oil;

• OPASC Oil Pipeline: used for distribute derivatives from REPAR to Santa Catarina State;

• GASBOL Gas Pipeline: supplies Southern Brazil with natural gas from Bolivia.

After several days of heavy and steady rain, on 11th March 2011 the rainfall reached the peak of 180mm in 24 hours what generated more than 50 geotechnical and hydrotechnical occurrences in OSPAR stream at Serra do Mar crossing,.

The actions, necessary to reducing the hazard, required stopping of oil pipelines, decrease of internal pressure in the gas pipeline, rearrangement of internal staff and machinary structure, and support of external companies structure, such as partnerships companies and new emergency contracts including heavily aircraft support, staffs and machines.

The emergency works, carried out in the occasion, leaded to the return of pipeline operations in less than five days. The total pipeline security was established with the stabilization of more than 50 geotechnical and hydrotechnical occurrences.
Overview of Pipeline Geohazard Assessment Approaches and Strategies
Authors: Rizkalla Moness , Read R. S. (Rod)
Published: January 2014

Undertaking a systematic pipeline geohazard assessment may be driven by the design and regulatory permitting needs for proposed new pipelines or as an input to the integrity management of operating pipeline assets. Yet the leading international pipeline codes do not provide explicit direction on undertaking such assessments, rather providing considerable latitude in the guidance to do so which in turn provides several options. The methods for identifying and assessing the potential likelihood and severity of geohazards vary significantly, from purely expert judgment-based approaches relying largely on visual observations of geomorphology to analytically-intensive methods incorporating phenomenological and/or mechanistic models and route, pipeline properties and, where applicable, operational monitoring data. Each of these methods can be used to assess hazard and risk associated with specific geohazards in terms of qualitative, semi-quantitative or quantitative approaches provided that associated underlying assumptions are clearly understood. Some of these methods are better suited to provide a continuous contiguous geohazard risk assessment for a pipeline system while others are better suited for localized site-specific risk assessments. Following a brief review of pipeline codes, this paper provides an overview of the range of pipeline geohazard assessment approaches and explores the “fitness for purpose” strategy that allows for continuing improvement during design stages and into operations.
Geotechnical Aspects of a Pipeline Rupture in Ecuador: Factors and Mitigation
Authors: Oswell James M. , Chiriboga Gualberto
Published: January 2014

In February 2009 a pipeline rupture occurred along a sloped section of the Oleoducto de Crudos Pesados (OCP) Ecuador S.A. pipeline. The spill resulted in crude oil flowing down the hillside and into the Rio Santa Rosa.

Post rupture investigations were initiated to identify the geotechnical factors that may have contributed to the incident and what mitigation may be necessary to ensure future pipeline integrity. The investigation consisted of several activities including detailed site reconnaissance by a geotechnical engineering team and installation of slope inclinometers to assess ground movements. The intent of the slope inclinometers was to determine the depth, areal extent and rate of ground movement, if any.

The post rupture site reconnaissance identified a number of terrain features consistent with shallow ground movement mechanisms. The presence of hummocky terrain could be the result of ground movement or an artifact of the use of the slope as cattle pasture.

Five slope inclinometers were installed to assess the slope movements within the project site. Four slope indicators were installed up-slope of the pipeline right-of-way to provide some lateral boundary to the ground movement area. The slope inclinometers showed that in the months following the pipeline rupture the terrain upslope of the pipeline right-of-way was moving at a relative constant rate of about 0.45 mm/day.

As a result of the geotechnical investigations an integrity mitigation plan was developed. This included ongoing slope movement monitoring, regular site reconnaissance and placement of the pipeline above ground on “sleepers” to isolate the pipeline from the underlying creeping slope. To-date, these mitigations have been successful in reducing strain on the pipeline.
Rerouting of a Pipeline due to Landslide Reactivation in an Andean Valley
Authors: Bustinza Juan A. , Rocca Ricardo J. , Zeballos Marcelo E. , Terzariol Roberto E.
Published: January 2014

The bi-national pipeline Loma de la Lata (Argentina)-Talcahuano (Chile) belonging to Gas del Pacifico, crosses the Andes at Latitude 37.1° South (Buta Mallin pass), following the Lileo river valley. In the region, there are large ancient landslides within an area of about 50 km2, which have been attributed to Holocene glaciations and seismic activity. In the winter of 2005, when snow limited the access to the area, it was found a pressure loss, that later was attributed to a landslide in a sector of the south bank of the valley. The adiabatic expansion generated a considerable volume of frozen soil around the pipe. The following summer it was studied the characteristics of the sliding and analyzed different solutions of the affected section. The geotechnical study showed details of the slipped area and its relationships with ancient landslides. It was found by comparative analysis of aerial photographs that an old slide about 1 km3 was not fully reactivated. The general morphology has remained unchanged at least in the last 50 years, when the oldest aerial photography was taken. As additional verification, it was found that a small set of cascading ponds located in the slipped mass, has remained stable at that time, bearing the influence of the great 1960 Mw = 9.6 Valdivia earthquake. It was identified tension cracks delimiting the slipped area that was a modest portion of the historical landslide. Geotechnical parameters were estimated by back analysis of the land involved and it could establish a model for sliding mass process. A general analysis of long-term stability took into account the influence of distant earthquakes such as the subduction zone, which has a recurrence of about 100 years and other local seismic sources. Prior to define the most appropriate solution, a 250 meters long trench was dug preventively releasing the pipeline from the terrain to avoid new deformations. Among the solutions considered were the construction of an absorption system with movement monitoring, or the relocation of the trace on the opposite bank of the river. It was decided to adopt the latter solution due to the difficulty of ensuring the stability of the terrain and the inaccessibility during the winter. It implied an additional river crossing and consequently, the need to monitor the stability of the channel to the river erosion.
Arbuscular mycorrhizal fungi alleviate oxidative stress in pomegranate plants growing under different irrigation conditions
Authors: Bompadre María Josefina , Silvani Vanesa Analía , Bidondo Laura Fernández , Ríos de Molina María Del Carmen , Colombo Roxana Paula , Pardo Alejandro Guillermo , Godeas Alicia Margarita
Published: January 2014

Drought greatly affects the growth and development of plants. This stressful condition can trigger an increase in reactive oxygen species (ROS) production that, in turn, can induce cellular, anatomical, and morphological changes that improve drought tolerance. A strain of arbuscular mycorrhizal fungi (AMF) is considered efficient when it colonizes roots quickly and extensively, absorbs and transfers nutrients to the plant host, promotes soil aggregation, and protects the host against disease. We evaluated the effect of inoculation of two strains of the AMF Rhizophagus intraradices (N.C. Schenck & G.S. Smith) C. Walker & A. Schüßler (GA5 and GC2) on pomegranate plants (Punica granatum L.) under two irrigation conditions. The response to oxidative stress depended on many factors, including the organism tissue and the degree of stress. Our study showed that, in most cases, mycorrhizal plants increased antioxidant defenses, such as the ROS-scavenging enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in shoots under both irrigation levels, whereas the response for roots was ambiguous. AMF inoculation maintained the levels of malondialdehyde (MDA), probably by rapidly increasing antioxidant defenses and preventing lipid damage. We show that early AMF inoculation (particularly with the GC2 strain) in pomegranate propagation protects plants against abiotic stress.