bluuebunny/crossref_metadata_2025 huggingface dataset:
Wellbore Stability Analysis for Trouble Free Drilling
Authors: Haidary S. A. , Shehri H. A. , Abdulraheem A.. , Ahmed M.. , Alqam M. H.
Published: October 2015

This study systematically investigates the mechanical instability of a wellbore as a function of rock mechanical properties and in-situ earth stresses, and validates the predicted failures with post-drilling problematic wells. Results from this study will help to avoid wellbore instability related issues.

Extended Reach Wells (ERD) were drilled in field X through shale formations inter-bedded by unconsolidated sandstone formations and carbonate formations which experienced severe wellbore instabilities.

Rock mechanics lab tests were performed on preserved core samples and all the available well logs were obtained and subsequently analyzed thoroughly to develop the rock mechanics properties profile.

Daily drilling reports were analyzed and this drilling history was used to evaluate the best failure criterion for modeling purposes. Accordingly, Mogi-coulomb was found to be the most appropriate failure criterion that matches the drilling history failures with predicted failures and can be used for more accurate future wellbore problem predictions.

An industrial geomechanical software was used to build a Mechanical Earth Model (MEM). The software output was calibrated and validated with the observed failed wellbore condition in selected drilled wells.

Subsequently, the root causes of different wellbore instability problems were identified. After preliminary validation of the MEM, the safe mud weight window for drilling future wells was predicted with respect to each formation by providing plots for different inclinations and azimuths.

The safe mud weight windows for drilling in any inclination, azimuth and measured depth for Aruma, Rumaila, Ahmadi, Safaniya, Biyadh and Buwaib were found and reported. Furthermore, the safest mud weight window that works for the entire section at any inclination, azimuth and measured depth was discovered and reported for the fisrt time.

Results from this study indicate that the predicted mud weight window profile could be adopted in future drilling operations for safe problem-free drilling in problematic formations.
Horizontal Drilling Challenges in the Thin Oil Sands of the Lower Burgan Formation, Kuwait- A Case Study
Authors: Chowdhuri Sankar , Abbas Nazar , Khan Ali , Sahib Raffi Madar , Gawwad Tarek Abdel , Chellappan Suresh , Omar Mohammad , Saleh Iskandar , Juyal Mukul , Wenang Martine , Osman Salih Noreldin
Published: October 2015

Horizontal drilling technology was used for the first time in the Middle Cretaceous Lower Burgan Layered Sand reservoir of Raudhatain Field, Kuwait for enhancement of oil production. The reservoir has been on production using conventional development techniques for the past 50 years.

The channel sands of the Lower Burgan Layered unit were targeted. These sands are much thinner than the world class Lower Burgan Massive Sand and became an ideal target for development by horizontal drilling. However these layered sands are very prolific and are at irreducible water saturation. These sands were de an ideal target for development by horizontal drilling. However these layered sands are very prolific and are at irreducible water saturation. These sands weic and are at irreducible water saturation. These sands were deposited in a clastic coastal environment. The complex geometry and heterogeneity make these sands a real challenge to place lateral boreholes within the sand.

The challenge of horizontal drilling through thin sand is to expose significantly more reservoir rocks in the wellbore which helps to increase the productivity.

This paper illustrates integration of LWD, geological, geophysical and engineering data for successful placement of the lateral sections within the targeted sands to maximize oil production.

In the 1st phase of horizontal drilling, laterals in 4 wells were placed in the Lower Burgan Layered sands at different locations over the Raudhatain structure. Length of laterals varied from 650–2000ft depending on the spatial distribution and geometry of sand bodies' vis-à-vis oil column. Effective geosteering through 7–12ft thick oil sands in these wells encountered 0.5 – 1.5 Darcy reservoirs. These oil sand layers produced from 850 BOPD to 4500 BOPD on initial production testing.

The success obtained in producing from these sand layers proved to be very effective and greatly enhanced the production from Raudhatain Field, Kuwait.
Use of Mud Gas Chromatograph for Reservoir Quality Prediction While Drilling - A Case Study
Authors: Dashti Jalal , Al-Mulla Khaled , Al-Kandari Eman , Al-Ajmi Bader , Rao Sudhakar , Al-Qattan Faisal , Al-Kandari Abdullah , Al-Bedawi Yousef , Al-Meshilah Thuwaini , Sabri Hamid , Al-Adwani Khalid , Estarabadi Javad , Shoeibi Ahmad , Ferroni Gionata , Janbakhsh Mehrdad
Published: October 2015

While drilling through a reservoir, a lot of valuable information can be obtained from mud logging to support formation evaluation. Field data will help wellsite geologists, petrophysicist and reservoir engineers to predict reservoir quality, fluid contacts and reservoir permeability based on formation gases detected while drilling. This study discusses some examples from exploratory wells that have recently been drilled in Kuwait. Gas readings were recorded while drilling through Cretaceous and deep Jurassic formations to evaluate hydrocarbon content using Advanced Gas Chromatography. The primary components of the system utilized are: a constant volume gas extractor, a gas sample flow control system, and a high resolution chromatographic system. To interpret the findings Gas readings are monitored by a complex system which provides real-time continuous measurements of the concentration of formation gases from very light components such as methane, to heavy components such as C6, C7 and C8 hydrocarbon species, comprising n-hexane, n-heptane, n-octane, benzene and toluene. Formation gas is considered as the first indication of a reservoir's fluid characterization and reflects the extent of the productivity of the well. Geochemical ratios and equations can enhance the interpretation of field data and give the first indication of zones of interest that need further evaluation.

The integration of the gas data along with the drilling parameters (ROP, ΔFlow) can be of valuable inputs to quantify the Rock properties such as porosity and permeability, this new approach can extend the utilization of gas data not only for formation evaluation and fluid characterization but also for formation petro-physical structure.

To take advantage of the field data, the gas readings are plotted on a depth log, which can be easily integrated with other data. Geochemical equations are plotted against depth and lithology to determine fluid type, contacts and evolution.
Understanding Shale-Fluid Interactions Using Molecular Modeling Techniques for Drilling Applications: A Literature Review
Authors: Al-Arfaj Mohammed , Sultan Abdullah , Abdulraheem Abdulazeez
Published: October 2015

The use of water-based drilling fluids to drill shale formations can cause wellbore stability problems as a result of the reaction of water with clay minerals. Examples of wellbore stability problems include shale disintegration, swelling and sloughing. Different types of clays give different types of problems. For example, when it is exposed to water, a shale sample with a high percentage of smectite tends to swell while another shale sample with a high percentage of kaolinite tends to disintegrate and disperse. Consequently, there will be higher solids loading in the wellbore. Hence, the chance to get the pipe stuck increases and the hole cleaning efficiency of drilling fluid decreases significantly.

To combat the abovementioned challenges and study the shale rock to be drilled, a series of tests should be conducted. The selection of the testing procedures and fluids to test shale samples with has been selected mainly on empirical basis involving trial and error. Molecular modeling technique can be utilized before taking the shale samples to the laboratory to provide theoretical background on the rock-fluid interactions at molecular scale. One advantage of this approach is to gain better understanding of the rock-fluid interactions from theoretical point-of-view in order to explain why one shale inhibitor works and provides adequate inhibition for one shale sample but does not work properly for another sample. The second advantage is that having insights into the potential rock-fluid interactions can guide the research to include or exclude certain types of shale inhibitors and to shorten the trial and error procedure. These advantages provide a basis upon which future drilling fluids planning can be optimized to mitigate wellbore stability issues.
Unlocking Additional Reserves Using Horizontal Wells with Multi Stage Fractures in the Western Desert of Egypt
Authors: AbdElNasser M. G. , Al-Maraghi A.M.. M. , Abady S. M.
Published: October 2015

This paper presents a case study for drilling a horizontal well with multi stage transverse fractures in the NEAMA field in Karma concession in the western desert of Egypt. The well production results are expected to lead the Western Desert operators to change the development strategy for several western desert fields to unlock the unrecovered reserves in the upper Baharia tight formation.

NEAMA field has total of 9 wells: 5 wells on production with total production around 500 BOPD, and 4 shut-in wells due to low productivity. The field STOIIP is around 15 MMSTB. With the historical low initial production rates, it was decided to develop the stranded reserves by drilling a horizontal well to replace three vertical wells and test the feasibility of applying horizontal wells with multi-stage fracturing in such tight reservoir.

A horizontal well with 7 fracturing stages was completed at the down-dip part of the field, LWD (Logging While Drilling) measurements were used to control well's direction and predict rock lithology. The LWD helped to control the well trajectory between the upper and lower boundaries of the reservoir's zone of interest. The well was completed with permanent downhole pressure gauge and ESP system in the vertical hole.

The well was put on production with initial rate of 400 BOPD with 20% water cut which was four times the total field production. The well production was maintained at low water cut until water production increased significantly. Integrated analysis of all collected data revealed that water channeling behind casing was responsible for the excessive water production. It was planned to work over the well to restore its oil production.

The paper discusses the integrated data analysis techniques that led to the choice of completion option of horizontal well with transverse fractures for new wells in NEAMA field. The results and additional analyses of both pressure and production data are expected to help other Western Desert operators to develop significant reserves of tight UBAH reservoir.
Field Development and Well Planning in Tight Carbonate Reservoir Using Fracture Characterization and In-Situ Stress Mapping From Core Reorientation Studies: Kuwait Case Study
Authors: Pattnaik Chinmaya , Rao Narhari Srinivasa , Al-Ashwak Samar , Al-Ajmi Neema Hussain , Kidambi Vijaya Kumar , Al Anzi Abdullah Motar , Dashti Qasem , Staffelbach C.. , Barbé Jean-françois
Published: October 2015

Fracture characterization is vital for efficient field development of naturally fractured Carbonate reservoirs. Successful development of fracture reservoir in the study area was possible due to early recognition of fracture play right from the exploration phase and through careful execution of relevant data acquisition campaign in the initial stages of field development. Comprehensive and integrated studies have been carried out over the past few years to arrive at an understanding of the conceptual model in deciphering structural evolution of North Kuwait Jurassic.

Extensive core and image log data was acquired in the initial stages of field appraisal, which helped in comprehensive forward planning in design of deviated and horizontal wells. The data analysis steps included accurate and reliable reorientation of the cores. These data were calibrated with the image logs, along with available seismic attributes, which resulted in better understanding of structural evolution and sweet spotting of horizontal wells. This reorientation of the core data also helped in establishing a number of quantitative fractures attributes such as frequency, spacing, dip-azimuth and aperture along with mapping of in-situ stress directions. The detailed integration of these data also helped in accurately mapping the local and regional present day stress and its variations spatially across the fields. Stress direction across the field was helpful for deciding the azimuth of wells during well planning along with selection of completion strategy for current set of horizontal drilling Campaign.

Drilling and testing results have been encouraging through enhanced reservoir performance in these tight carbonate reservoirs, based on these integrated studies.
Simultaneous Sorption and Mechanical Entrapment During Polymer Flow Through Porous Media
Authors: Farajzadeh R.. , Lotfollahi M.. , Bedrikovetsky P..
Published: October 2015

Physical adsorption and mechanical entrapment are two major causes of polymer retention in porous media. Physical adsorption is believed to be an equilibrium process and is often modelled by assuming a Langmuir isotherm. The outcome is steady-state pressure response because the permeability reduction is also accounted for by adsorption. However, some experimental data show gradual increase of pressure with time implying that polymer retention is a kinetically-controlled process.

In this paper, we discuss simultaneous effect of sorption and mechanical retention on the polymer retention in porous media. An exact solution for 1-D flow problem for the case of constant filtration coefficient and Langmuir sorption isotherm, including explicit formulae for breakthrough concentration and pressure drop across the core is derived. The general model with varying filtration coefficient was successfully matched with coreflood data confirming the occurrence of simultaneous sorption with deep bed filtration.

In the absence of mechanical entrapment, the physical adsorption causes delay in the polymer front and does not affect the polymer concentration behind the front. Addition of mechanical entrapment results in very slow recovery of the injected concentration at the outlet (for varying filtration coefficient) or reaching to a steady-state concentration, which is only a fraction of the injected concentration (for a constant filtration coefficient). The results indicate that the accurate assessment of polymer retention requires both pressure and effluent concentration data at the outlet of the porous medium. In many cases, the kinetics involved in the mechanical entrapment could be very slow. In such cases, the experiments with few pore-volumes of injected polymer can be misleading and should not be directly used for field simulations.
Foam Stabilized by Fly-Ash Nanoparticles for Enhancing Oil Recovery
Authors: Eftekhari Ali Akbar , Krastev Rumen , Farajzadeh Rouhi
Published: October 2015

Foam has been employed as an Improved/Enhanced oil recovery (IOR/EOR) method to overcome gravity override and the channeling and fingering of the injected gas, which arises due to the low density and viscosity of the injected fluid combined with the rock heterogeneity. A major challenge; however, is the stability of the generated foam when it contacts the oil. Foam boosters, which are generally costly surfactants, have been co-injected together with the main foaming surfactant to create stable foams in the presence oil. Similar to surfactants, particles can also accumulate at the gas-liquid and liquid-liquid interfaces. The difference is that the energy of adsorption and desorption of particles to the interface is so large that their adsorption is considered irreversible. Nanoparticles are orders of magnitude smaller than pore throats and therefore can easily flow through porous media.

In this study we investigate the possibility of replacing the expensive foam boosters with inexpensive nanoparticles made of coal fly-ash, which is abundantly available as a by-product of coal power plants. We investigate the viability of reducing the size of fly-ash particles using high frequency ultrasonic grinding. We also study the foaminess (foamability) and stability of the foams made with minor concentrations of fly-ash nanoparticles and surfactant both in bulk and porous media. The effect of monovalent and divalent ion concentration on the foaminess of the nano-ash suspension combined with very low concentrations of a commercial alpha olefin sulfonate (AOS) surfactant, in presence and absence of oil, is studied.

We observe that bulk foam that contains very small amounts of nano-ash particles shows a higher stability in presence of model oils. Furthermore, experiments in porous media exhibit remarkably stronger foam with mixtures of nano-ash and surfactant, such that the amount of produced liquids from the cores significantly increases. In presence of oil, the nano-ash-AOS foam shows a higher stability, although crude oil tends to form stable emulsions in water in presence of nano-ash.
Visualization of Oil Mobilization in ASP Core Floods Using X-ray CT Imaging
Authors: van Batenburg D. W. , Berg S.. , Oedai S.. , Elewaut K..
Published: October 2015

This paper describes a series of experiments that used X-ray computer tomography (CT) to visualize the mobilization of remaining oil by Alkaline Surfactant (AS) and Alkaline Surfactant Polymer (ASP) flooding after conventional waterflooding. The experiments were conducted in cores drilled from Gildehauser and Bentheimer sandstone outcrop material with diameters of approximately 7.55 cm and lengths of approximately 27 cm and one meter. Crude oil with in-situ viscosities of 1.3, 2.3 and 100 cP was used in the experiments. The changes in the fluid saturation distributions with time obtained with X-ray computer tomography are subsequently used to improve the conceptual understanding of the ASP process.

In addition to pressure and effluent data collected during conventional core flood experiments, phase and saturation distributions in space and time are needed to more completely interpret the results of core floods. This additional information reveals underlying mechanisms, and assists the development of models that capture the physics of ASP that can ultimately be used to provide field scale predictions for ASP performance.

One important observation from the experiments is that there exist a consistent fingering pattern in the zone upstream of the oil bank. Although fingering is often considered a bad sign for a displacement process the experiments also demonstrate that the fingering zone is contained in the area upstream of the oil bank and that the velocity of the front of the oil bank is significantly greater than that of the fingering zone. The production following the clean oil bank (tail) observed in many ASP core floods is a consequence of the formation of this fingering zone.

Effluent analyses conducted on the produced fluids from the long core experiments showed a sharp, rapid build up in polymer viscosity that coincides with the beginning of the tail production while the surfactant concentration only gradually increases to its injection value during the tail production.

Another important observation is that a characteristic self-similar cross-sectional averaged oil saturation profile develops during ASP injection after water flood in cores containing reactive crude oil with 100 cP viscosity and in non reactive light crude oil.

The implications of the self-similarity of the saturation profiles in combination with the observation that the surfactant propagation is retarded with respect to the polymer propagation results in a polymer flood ahead of the ASP-slug and a corresponding characteristic oil production profile. The characteristics of this process can be captured with an extended fractional flow approach that utilizes three fractional flow curves: one for the ASP-slug, one for polymer, and the original fractional flow curve for oil-water.
Biomass Production and Carbon/Nitrogen Ratio Influence Ecosystem Services from Cover Crop Mixtures
Authors: Finney Denise M. , White Charles M. , Kaye Jason P.
Published: October 2015

Increasing plant diversity in agroecosystems with cover crops has been a successful strategy to augment ecosystem services from agriculture, and increasing diversity of cover crops may provide even greater benefits. Productivity and ecosystem services from multi‐species cover crop mixtures were measured in a 2‐yr field study of 18 cover crop treatments preceding conventionally tilled corn in central Pennsylvania. Increasing the number of species in a stand increased cover crop biomass (R2 = 0.15). However, mixing cover crop species that were complementary in phenology or N acquisition strategy did not result in mixtures that produced more biomass than high yielding monocultures. Increasing cover crop biomass was positively correlated with several ecosystem services, namely weed suppression, prevention of nitrate leaching, and aboveground biomass N, but negatively impacted inorganic N availability and corn yield in the subsequent cropping season. The cover crop C/N ratio was another determinant of ecosystem services positively related to nitrate leaching prevention, but negatively related to inorganic N availability and corn yield. This study supports the long‐held assumption that increasing biomass can enhance certain ecosystem services from cover crops; however, because the mixtures tested did not produce more biomass than high yielding monocultures, opportunities to increase biomass‐driven services with mixtures may be limited. The correlation between biomass C/N ratio and ecosystem services in this study also indicates that functional traits, as opposed to biomass alone, will be important for predicting ecosystem services from cover crop mixtures.
Modifying Winter Wheat Sowing Date as an Adaptation to Climate Change on the Loess Plateau
Authors: Ding D. Y. , Feng H. , Zhao Y. , He J. Q. , Zou Y. F. , Jin J. M.
Published: October 2015

Adopting convenient strategies to cope with climate change is necessary for farmers. In this study, we modified winter wheat (Triticum aestivumL.) sowing date employing the root zone water quality model (RZWQM2) on the semiarid Loess Plateau of China, and mainly aimed to (i) investigate how the adapted sowing date affects winter wheat production and water use efficiency (WUE) under global warming and (ii) explore the optimal sowing date under different precipitation patterns (i.e., wet, medium, and dry years). Results showed that the RZWQM2 model could efficiently simulate crop development, water movement, and final crop yields on the Loess Plateau. The properly delayed sowing date efficiently maintained wheat yield, reduced evapotranspiration, increased WUE, and minimized the decreasing rate of wheat yield and WUE under global warming from the 1950s. To maintain a high level of yield under global warming, the wheat sowing date could be delayed by 10 to 20 d in the wet and medium years, and by 20 to 25 d in the dry year compared with the current sowing date. Therefore, a delayed sowing date could be used on the Loess Plateau and even similar semiarid environments in the world to cope with climate change for farmers.
Effects of Immediate Dentin Sealing and Pulpal Pressure on Resin Cement Bond Strength and Nanoleakage
Authors: Santana VB , de Alexandre RS , Rodrigues JA , Ely C , Reis AF
Published: October 2015

Objective: The object of this study was to evaluate the simulated pulpal pressure (SPP) and immediate dentin sealing technique (IDS) effects on the microtensile bond strength (μTBS) and nanoleakage of interfaces produced by different luting agents.

Methods and Materials: Two self-adhesive luting agents (RelyX Unicem [UC] and Clearfil SA Luting [SA]) and two conventional luting agents (Rely X ARC [RX] and Panavia F [PF]) were evaluated. Eighty human molars were divided in four groups according to luting agents. Each group was subdivided according to SPP (with or without) and dentin sealing (immediate or delayed) using Clearfil SE Bond (n=5). After IDS was performed, specimens were stored in water for seven days before luting procedures. Composite blocks were luted according to the manufacturers' instructions. One half of the specimens were subjected to 15 cm H2O of hydrostatic pressure for 24 hours before cementation procedures and continued for 24 hours afterward. Then, restored teeth were sectioned into beams and tested in tension. Two additional teeth per group were prepared for nanoleakage evaluation with scanning electron microscopy. Bond strength data were statistically analyzed by three-way analysis of variance and Tukey test.

Results: μTBS of RX decreased when it was subjected to SPP without IDS. However, in the same conditions, μTBS of UC increased. The IDS prevented negative influence of SPP on μTBS of RX and PF; however, a decrease in μTBS of SA and UC was observed. Except for RX, IDS increased μTBS for all resin cements.

Conclusion: Independent of SPP, the IDS technique obtained higher μTBS for PF, SA, and UC and did not influence RX μTBS.
Predictors of Outcome in Neonates with Respiratory Distress
Authors: John BM , Venkateshwar V , Dagar V
Published: October 2015

Introduction: Many of the parameters utilised in scoring systems used to predict disease severity in respiratory distress in neonates are not readily available in the primary care facility of developing countries. This study was carried out to assess the utility of birth weight, gestational age, APGAR score at 5 min, baseline oxygen saturation and Downe’s score in prediction of requirement of respiratory support and mortality in neonates with respiratory distress.Material and Methods: A prospective study was carried out in the neonatal intensive care unit of a tertiary teaching hospital. 165 consecutively admitted neonates presenting with respiratory symptoms were included in the study. The relevant parameters and investigations were documented in a structured performa. The neonates were followed up for outcomes which included requirement of respiratory support and mortality.Results: A higher mortality was associated with birth weight of < 1620 grams, gestational age of < 31 weeks, APGAR score of < 6, Downe’s score of > 3 and baseline oxygen saturation of < 86 % (p values < 0.001). The requirement of mechanical ventilation was more with birth weight of < 2000 grams, gestational age of < 32 weeks, APGAR score of < 7, Downe’s score of > 4 and baseline oxygen saturation of < 87 % (p value < 0.001). The requirement of any respiratory support at 72 hours was associated with birth weight of < 1894 grams, gestational age of < 37 weeks, APGAR score of < 7, Downe’s score of > 3 and baseline oxygen saturation of < 89 % ( p-value <0.001).Conclusions: Readily available parameters like birth weight, gestational age, APGAR score, oxygen saturation and Downe’s score could together be used to predict mortality and requirement of respiratory support in the resource limited setting. J Nepal Paediatr Soc 2015;35(1):31-37
Barriers to Implementation of Climate Adaptation Frameworks by State Departments of Transportation
Authors: Dowds Jonathan , Aultman-Hall Lisa
Published: October 2015

Disruptive events caused by weather extremes are imposing significant and rising costs on transportation agencies. In response, federal and state transportation agencies and other organizations are exploring adaptation measures to reduce the adverse consequences of these events. Several existing adaptation frameworks are synthesized here into a simplified, core adaptation framework, and the study seeks to delineate the current barriers to the widespread implementation of adaptation programs by state departments of transportation in the United States. From interviews with transportation practitioners and a review of the results from FHWA pilot projects, it is found that uncertainty about future climate conditions, the need for additional vulnerability-modeling tools, conceptual uncertainty about evaluating asset criticality, and limited funding all inhibit implementation of adaptation measures.
Integrating Stochastic Failure of Road Network and Road Recovery Strategy into Planning of Goods Distribution after a Large-Scale Earthquake
Authors: Wisetjindawat Wisinee , Ito Hideyuki , Fujita Motohiro
Published: October 2015

Disaster relief operations are complex and can benefit greatly from a high level of preparedness. One of the main sources of complexity in disaster operations is uncertainty. An analysis of a disaster relief operation in Aichi Prefecture, Japan, preparing for the periodic Tokai–Tonankai earthquake is presented. In this study, the possible degradation of the road network is considered by including a stochastic element to represent the possibility of link failure dependent on earthquake intensity in each subregion. Also, a strategy to fix the roads is integrated into the analysis to evaluate its impact on the disaster logistics operations. The analysis is performed with the current road network of Aichi Prefecture. The results suggest the best preparation of resources and identify vulnerable destinations that are most likely to be cut off by the disaster. Also analyzed is a relocation of hubs that can reduce the total response time and take into account the possibility that some links will be destroyed. This analysis is important to help planners to evaluate their strategies, to identify vulnerable locations, and to be able to prepare in advance the best methods to deal with the uncertainty of road failure.
Multimodal Evacuation Simulation and Scenario Analysis in Dense Urban Area
Authors: Yuan Fang , Puchalsky Christopher M.
Published: October 2015

Simulation is an effective tool for estimating evacuation times, identifying system bottlenecks, and evaluating traffic management strategies under a variety of operational and behavioral assumptions. The development of a multimodal simulation model for modeling evacuation activities in Center City, Philadelphia, Pennsylvania, is presented. The model applied a dynamic sequential assignment method to simulate the movement and interactions of pedestrians, private vehicles, and buses while considering the variation of evacuation demand and network conditions during evacuation operations. The model was used to perform scenario analysis and provide inputs to update current evacuation plans. This study shares the experience and findings from the Philadelphia study in modeling multimodal evacuations in dense urban areas.
Spatiotemporal Population Distribution Method for Emergency Evacuation
Authors: Bian Ruijie , Wilmot Chester G.
Published: October 2015

Knowing where people are is important in emergency management. This study presents a spatiotemporal method to estimate population distribution by time of day, day of the week, and season of the year. Population is broken into six groups: residents, workers, students, stay-at-homes, shoppers, and tourists. The last two groups have usually been neglected in studies. However, these groups can be significant portions of the population in certain environments and display unique variations. In this study, population is distributed by using dasymetric mapping; the distribution of the population is based on land use. However, two modifications are made. First, preprocessing of coarse land use categories with residential density and employee data allows the distinction between resident, worker, shopper, and tourist in the distribution process. Second, the relationship between population and land use is based on regression of existing data instead of on subjective judgment or sampling as in current dasymetric methods. The method is demonstrated in an application to downtown New Orleans, Louisiana, to evaluate the population affected by a hypothetical chemical spill. In one case, the spill is assumed to occur on a weekday afternoon during a local festival. About 83,000 people are estimated to be affected, with most being workers and tourists. In the other case, the same spill is considered to occur over the weekend at night during a period when no festival is in progress. In this case, 39,000 people are estimated to be affected, most of them residents and tourists spread throughout the area within the plume.
Joint Evacuation and Emergency Traffic Management Model with Consideration of Emergency Response Needs
Authors: Konstantinidou Maria A. , Kepaptsoglou Konstantinos L. , Karlaftis Matthew G. , Stathopoulos Antony
Published: October 2015

During and after a disaster, transportation network management is a complex task. In a state of limited serviceability and functionality, surviving transportation infrastructure is expected to act as a vital lifeline and to support different types of operations. This study investigates the joint planning of evacuation operations and emergency traffic management while accounting for emergency response needs. Extended wildfires across a highway network are the assumed disaster setting. Population evacuation takes place by using part of the network, whereas emergency traffic management strategies are applied outside the evacuation zone. Network performance enhancement is pursued through the implementation of lane reversal. The problem is formulated as a two-stage optimization model; minimization of total evacuation time (TET) and minimization of total network travel time (TNTT) are the upper-level objectives for the evacuation area and the rest of the network, respectively. The lower level corresponds to a traffic assignment model on the basis of user equilibrium. Demonstration of the model on a real-world network proves the computational efficiency of the algorithm. The model systematically produces robust results in terms of TET-TNTT minimization and thus addresses the operational needs arising and enhances overall transportation network performance.
Selecting Four-Leg Intersections for Crossing Elimination in Evacuations
Authors: El-Metwally Maha , Murray-Tuite Pamela
Published: October 2015

This study investigates the implementation of crossing elimination con-figurations at intersections, by neighborhood characteristics; a “neighborhood” is defined by its surrounding intersections and by supply and demand situations to identify evacuation travel time impacts and situations and crossing elimination configurations that should be considered and further investigated for implementation in practice or should be avoided in practice. A hypothetical network of 41 signalized intersections modeled in microscopic simulation software was used to test 104 scenarios. On the basis of the analyses, crossing elimination should be considered and should be further investigated for evacuations with high demand and when the evacuation flow is asymmetric but oriented with the major roads. Crossing elimination should generally be avoided or carefully implemented when the evacuation flow is asymmetric but oriented with the minor roads and when destinations aligned with major roads (rather than minor ones) are unreachable (in at least one of the two directions). This latter situation is the one exception to the high demand recommendation. Pairing of intersection location and crossing elimination configuration is more complicated in terms of the effects on total travel times across scenarios.
Using Dynamic Flashing Yellow for Traffic Signal Control under Emergency Evacuation
Authors: Asamoah Charles A. , He Qing
Published: October 2015

Effective signal timing plans for emergency evacuation are crucial for public safety. Two conflicting objectives of emergency evacuation in a corridor are to increase throughput on the main street (evacuation route) and to decrease delay on the side streets. Previous studies have proved the effectiveness of using the static flashing yellow signal timing plan in evacuating a high number of vehicles. However, the static flashing yellow plan also yields extremely high delay on side streets. This study investigates a variant of the static flashing yellow plan called the dynamic flashing yellow (DFY) signal timing plan under a few reasonable assumptions. The DFY plan consists of two signal phases. Phase 1 is flashing yellow on the main street and flashing red on the side street, whereas Phase 2 is a red signal on the main street and a green signal on the side street. Three types of DFY plans are proposed, including fixed DFY, actuated DFY, and actuated and coordinated DFY. This study demonstrates that the DFY provides a high volume of evacuated vehicles with relatively lower delay to the side street traffic. Moreover, the DFY is adjustable to favor different weights between network throughput and average delay. To compare the DFY with the static flashing yellow and other plans, VISSIM is implemented to model a 4.1-mi corridor in Buffalo, New York. The DFY plan is further analyzed by method and cycle length. According to the Pareto frontier, the actuated and coordinated DFY with cycle lengths of 60 s and 120 s produces more desirable results (Pareto nondominated solutions) than other plans.
Face, content, and construct validity of human placenta as a haptic training tool in neurointerventional surgery
Authors: Ribeiro de Oliveira Marcelo Magaldi , Nicolato Arthur , Santos Marcilea , Godinho Joao Victor , Brito Rafael , Alvarenga Alexandre , Martins Ana Luiza Valle , Prosdocimi André , Trivelato Felipe Padovani , Sabbagh Abdulrahman J. , Reis Augusto Barbosa , Maestro Rolando Del
Published: October 2015

OBJECT

The development of neurointerventional treatments of central nervous system disorders has resulted in the need for adequate training environments for novice interventionalists. Virtual simulators offer anatomical definition but lack adequate tactile feedback. Animal models, which provide more lifelike training, require an appropriate infrastructure base. The authors describe a training model for neurointerventional procedures using the human placenta (HP), which affords haptic training with significantly fewer resource requirements, and discuss its validation.

METHODS

Twelve HPs were prepared for simulated endovascular procedures. Training exercises performed by interventional neuroradiologists and novice fellows were placental angiography, stent placement, aneurysm coiling, and intravascular liquid embolic agent injection.

RESULTS

The endovascular training exercises proposed can be easily reproduced in the HP. Face, content, and construct validity were assessed by 6 neurointerventional radiologists and 6 novice fellows in interventional radiology.

CONCLUSIONS

The use of HP provides an inexpensive training model for the training of neurointerventionalists. Preliminary validation results show that this simulation model has face and content validity and has demonstrated construct validity for the interventions assessed in this study.
Evaluation and management of fibrofatty tumors of the extremities: case report
Authors: Wilson Thomas J. , Joseph Jacob R. , Dillman Jonathan R. , Heider Amer , Yang Lynda J. S.
Published: October 2015

Patients presenting with enlarging fibrofatty masses in the extremities pose an interesting dilemma to clinicians, as the differential diagnosis in such cases ranges from benign to malignant, and from lesions optimally managed operatively to those managed nonoperatively. The differential diagnosis includes benign lipoma, liposarcoma, lipoblastoma, and fibrolipomatous hamartoma (lipomatosis) of the nerves. The authors present the case of a 14-year-old girl with an enlarging fibrofatty mass of the forearm, initially thought, based on diagnostic imaging, to be a fibrolipomatous hamartoma of the median nerve, but found to be a lipoblastoma without direct nerve involvement based on histopathological examination of the operative specimen. This case serves to illustrate the diagnostic predicament that can exist with such masses. The authors advocate the need to establish a tissue diagnosis while having a contingency plan for each of the diagnostic possibilities because the management of each lesion is markedly different. In this report, the authors consider the differential diagnosis of fibrofatty masses of the extremities that the peripheral nerve surgeon may encounter, and they highlight the significant differences in management strategies for each possible diagnosis.
Microsurgical anatomy of safe entry zones to the brainstem
Authors: Cavalcanti Daniel D. , Preul Mark C. , Kalani M. Yashar S. , Spetzler Robert F.
Published: October 2015

OBJECT

The aim of this study was to enhance the planning and use of microsurgical resection techniques for intrinsic brainstem lesions by better defining anatomical safe entry zones.

METHODS

Five cadaveric heads were dissected using 10 surgical approaches per head. Stepwise dissections focused on the actual areas of brainstem surface that were exposed through each approach and an analysis of the structures found, as well as which safe entry zones were accessible via each of the 10 surgical windows.

RESULTS

Thirteen safe entry zones have been reported and validated for approaching lesions in the brainstem, including the anterior mesencephalic zone, lateral mesencephalic sulcus, intercollicular region, peritrigeminal zone, supratrigeminal zone, lateral pontine zone, supracollicularzone, infracollicularzone, median sulcus of the fourth ventricle, anterolateral and posterior median sulci of the medulla, olivary zone, and lateral medullary zone. A discussion of the approaches, anatomy, and limitations of these entry zones is included.

CONCLUSIONS

A detailed understanding of the anatomy, area of exposure, and safe entry zones for each major approach allows for improved surgical planning and dissemination of the techniques required to successfully resect intrinsic brainstem lesions.
The nondecussating pathway of the dentatorubrothalamic tract in humans: human connectome-based tractographic study and microdissection validation
Authors: Meola Antonio , Comert Ayhan , Yeh Fang-Cheng , Sivakanthan Sananthan , Fernandez-Miranda Juan C.
Published: October 2015

OBJECT

The dentatorubrothalamic tract (DRTT) is the major efferent cerebellar pathway arising from the dentate nucleus (DN) and decussating to the contralateral red nucleus (RN) and thalamus. Surprisingly, hemispheric cerebellar output influences bilateral limb movements. In animals, uncrossed projections from the DN to the ipsilateral RN and thalamus may explain this phenomenon. The aim of this study was to clarify the anatomy of the dentatorubrothalamic connections in humans.

METHODS

The authors applied advanced deterministic fiber tractography to a template of 488 subjects from the Human Connectome Project (Q1–Q3 release, WU-Minn HCP consortium) and validated the results with microsurgical dissection of cadaveric brains prepared according to Klingler’s method.

RESULTS

The authors identified the “classic” decussating DRTT and a corresponding nondecussating path (the nondecussating DRTT, nd-DRTT). Within each of these 2 tracts some fibers stop at the level of the RN, forming the dentatorubro tract and the nondecussating dentatorubro tract. The left nd-DRTT encompasses 21.7% of the tracts and 24.9% of the volume of the left superior cerebellar peduncle, and the right nd-DRTT encompasses 20.2% of the tracts and 28.4% of the volume of the right superior cerebellar peduncle.

CONCLUSIONS

The connections of the DN with the RN and thalamus are bilateral, not ipsilateral only. This affords a potential anatomical substrate for bilateral limb motor effects originating in a single cerebellar hemisphere under physiological conditions, and for bilateral limb motor impairment in hemispheric cerebellar lesions such as ischemic stroke and hemorrhage, and after resection of hemispheric tumors and arteriovenous malformations. Furthermore, when a lesion is located on the course of the dentatorubrothalamic system, a careful preoperative tractographic analysis of the relationship of the DRTT, nd-DRTT, and the lesion should be performed in order to tailor the surgical approach properly and spare all bundles.
Combined posterior hemiosteotomies and stabilization with lateral thoracotomy for en bloc resection of thoracic paraspinal primary bone tumors: technical note
Authors: Avila Mauricio J. , Skoch Jesse , Fennell Vernard S. , Palejwala Sheri K. , Walter Christina M. , Kim Samuel , Baaj Ali A.
Published: October 2015

Primary bone tumors of the spine are rare entities with a poor prognosis if left untreated. En bloc excision is the preferred surgical approach to minimize the rate of recurrence. Paraspinal primary bone tumors are even less common. In this technical note the authors present an approach to the en bloc resection of primary bone tumors of the paraspinal thoracic region with posterior vertebral body hemiosteotomies and lateral thoracotomy. They also describe 2 illustrative cases.
Ugwuele-Uturu: A Lithic Exploitation Site in South-East Nigeria
Authors: Allsworth-Jones Philip
Published: October 2015

The site of Ugwuele-Uturu was discovered in 1977 and excavated on two occasions between then and 1981. A number of general accounts were produced by the excavators, but to a large extent the site remains unpublished. No detailed account of the excavations or of the excavated material is widely available. In the meantime, controversy as to what the site represents continues, in the light of F.N. Anozie’s claim that it is Acheulean. This paper provides a record of the author’s visits to the site in 1978 and 1981, when he was a staff member of the University of Ibadan, and also presents some results from his study of the artefacts kept at the Department of Archaeology at the University of Nigeria Nsukka in 1980. In his view, on the basis of the available evidence, the site represents an axe factory of likely Holocene date. It is hoped that this record, apart from its historical documentary value, will stimulate new work on the site and the material from it, so that its nature can be established beyond doubt.
Shikonin Inhibits the Migration and Invasion of Human Glioblastoma Cells by Targeting Phosphorylated β-Catenin and Phosphorylated PI3K/Akt: A Potential Mechanism for the Anti-Glioma Efficacy of a Traditional Chinese Herbal Medicine
Authors: Zhang Feng-Ying , Hu Yi , Que Zhong-You , Wang Ping , Liu Yun-Hui , Wang Zhen-Hua , Xue Yi-Xue
Published: October 2015

Shikonin is an anthraquinone derivative extracted from the root of lithospermum. Shikonin is traditionally used in the treatment of inflammatory and infectious diseases such as hepatitis. Shikonin also inhibits proliferation and induces apoptosis in various tumors. However, the effect of shikonin on gliomas has not been fully elucidated. In the present study, we aimed to investigate the effects of shikonin on the migration and invasion of human glioblastoma cells as well as the underlying mechanisms. U87 and U251 human glioblastoma cells were treated with shikonin at 2.5, 5, and 7.5 μmol/L and cell viability, migration and invasiveness were assessed with CCK8, scratch wound healing, in vitro Transwell migration, and invasion assays. The expression and activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) and the expression of phosphorylated β-catenin (p-β-catenin) and phosphorylated PI3K/Akt were also checked. Results showed that shikonin significantly inhibited the cell proliferation, migration, invasion, and expression of MMP-2 and MMP-9 in U87 and U251 cells. The expression of p-β-catenin showed contrary trends in two cell lines. It was significantly inhibited in U87 cells and promoted in U251 cells. Results in this work indicated that shikonin displayed an inhibitory effect on the migration and invasion of glioma cells by inhibiting the expression and activity of MMP-2 and -9. In addition, shikonin also inhibited the expression of p-PI3K and p-Akt to attenuate cell migration and invasion and MMP-2 and MMP-9 expression in both cell lines, which could be reversed by the PI3K/Akt pathway agonist, insulin-like growth factor-1 (IGF-1).