Lateral Section Research Articles

Extent of cervical lymph node dissection: Recommendations from the Francophone Association for Endocrine Surgery, the French Society of Endocrinology and the French Society of Nuclear Medicine

When metastatic ipsilateral central lymph nodes from thyroid cancer are identified pre- or intraoperatively (cN1a), ipsilateral central lymph node dissection should be performed concomitantly with thyroidectomy. When the patient is N1a on one side, contralateral prophylactic central lymph node dissection can also be considered. Prophylactic ipsilateral lymph dissection is not recommended. Ipsilateral compartment lymph node dissection is recommended in the corresponding sector for treatment of thyroid cancer with lymph node involvement (cN1b). Lymph node dissection can be limited to sectors III and IV when one of these sectors (or both) is involved and ultrasound does not demonstrate involvement of the other lateral sectors. Associated prophylactic lymph node dissection of sectors IIA and IIB is not recommended, while lymph node dissection of sector V (and exceptionally sector I) is indicated only when metastatic lymph nodes are proven. Prophylactic lymph node dissection of sector VB can be considered when positive lymph nodes are identified in sectors II, III and IV. When isolated metastatic lateral lymph nodes are identified (cN1b), prophylactic central (sector VI) lymph node dissection is recommended on the same side as the lateral compartment in addition to ipsilateral lateral lymph node compartment dissection. The level of evidence is insufficient to recommend prophylactic lateral lymph node dissection on the contralateral side for unilateral cN1b tumors. This type of lymph node dissection can be discussed for tumors that are at high risk of recurrence, bilateral tumors, in case of ipsilateral lateral lymph nodes > 3cm or in presence of > 4 metastatic lymph nodes in the central compartment.

Advanced Diagnostics Aid Understanding at Hydraulic Fracturing Test Site 2

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTeC 2021-5514, “Overview of Hydraulic Fracturing Test Site 2 in the Permian Delaware Basin (HFTS-2),” by Jordan Ciezobka, SPE, GTI. The paper has not been peer reviewed. _ The Hydraulic Fracturing Test Site 2 (HFTS-2) is a large collaborative field-based research and development program in the Permian Delaware Basin funded by the US Department of Energy through the National Energy Technology Laboratory and the exploration and production industry with support from academia. The project’s main objective is to improve the understanding of the hydraulic fracturing process through use of advanced diagnostics and collection of through-fracture cores to provide undisputable evidence and attributes of created fractures. Project Background The HFTS-2 project provides the opportunity to address the optimal development of a stacked pay resource that requires simultaneous drilling and completion of tens of thousands of wells across multiple geologic horizons, also known as cube development. The project consists of a series of coupled analytic and field experiments in which research-quality data are acquired in dedicated research wells through full instrumentation at, and in proximity to, hydraulically fractured wells. Furthermore, the unique site design provides an opportunity to understand the effect of reservoir depletion because many child-well stages overlap parent-well areas. The extensive data set acquired was integrated and used to calibrate subsurface models and characterize fracture geometry and proppant distribution. Diagnostics and modeling efforts enabled comprehensive calculations of hydraulic fracturing’s vertical and lateral extent and production-depletion profiles and quantification of fracture growth bias for child-well stages that overlapped parent wells. Results from the project culminated in the development of a series of optimization procedures for increased drilling and completion efficiency, reducing environmental footprint by producing the reservoir from fewer well pads and fracturing stages. Test Site The research well package consists of eight new producing wells, two existing parent wells, and two new dedicated science and observation wells drilled for this project. The new producing wells are landed in various Wolfcamp horizons and have lateral lengths of approximately 7,500 ft. The lateral sections of the wells are spaced approximately 660 ft apart. The two existing parent wells also are in the Wolfcamp formation and have lateral lengths of approximately 5,000 ft. The two new science wells were drilled from the same pad, positioned between laterals B3H and B4H. One science well is a vertical pilot hole used to characterize the reservoir through the collection of mud and drill-cutting samples, electric logs, and whole and sidewall cores. The well also was used to house diagnostic instrumentation. The second science well is a slant well drilled after all wells were stimulated and was used to collect whole cores through the created fractures. The slant core well was instrumented with pressure and temperature gauges to monitor reservoir depletion during production.

Topographic features of the bone tissue quality of the frontal sinus walls in adults

Relevance of the research. A necessary condition for adequate diagnosis of changes occurring in bone tissue under the influence of various factors is deep and perfect knowledge of its quality indicators in healthy individuals, with mandatory consideration of age and gender characteristics. Therefore, the purpose of our study was to determine the regularities of the ratio of bone tissue density indicators of the frontal sinuses walls of different people sexes of mature age and to study the peculiarities of their age dynamics.Material and methods. The study was conducted by processing 40 series of archive anonymized computer tomography of 20 men and 20 women of mature age. The material for the study was obtained in the MC "Lithotripsy Center" (Lviv) on a Siemens SOMATOM GO.UP 32 (64) device (Germany). Bone density was determined on the inner and outer walls of the frontal sinus at the level of the brow ridges medially, laterally, and in the intermediate/middle area in Hounsfield units (HU). All statistical calculations were performed using BioStat LE 7.6.5 and IBM SPSS Statistics 21 software.Research results. The analysis of the density of bone tissue in different areas of the frontal sinuses’ walls of men and women of mature age proved that in all the examined sites, the studied indicator is higher in women than in men. Mostly, the outer wall of the frontal sinus has a greater density than the inner one (the exception is the medial section of the left frontal sinus). The density of the medial sections is higher than the lateral and intermediate sections (exceptions are the outer wall of the left frontal sinus of men after 35 years old and the outer wall of the right and left sinuses of women under the age 35).Conclusions. The density of bone tissue of the inner and outer walls of the frontal sinuses in the medial, intermediate, and lateral areas in women is higher than in men. In all the studied areas, the bone density indicators are asymmetric.

Retinoic acid signaling pathway perturbation impacts mesodermal-tissue development in the zebrafish embryo: Biomarker candidate identification using transcriptomics.

The zebrafish embryo (ZE) model provides a developmental model well conserved throughout vertebrate embryogenesis, with relevance for early human embryo development. It was employed to search for gene expression biomarkers of compound-induced disruption of mesodermal development. We were particularly interested in the expression of genes related to the retinoic acid signaling pathway (RA-SP), as a major morphogenetic regulating mechanism. We exposed ZE to teratogenic concentrations of valproic acid (VPA) and all-trans retinoic acid (ATRA), using folic acid (FA) as a non-teratogenic control compound shortly after fertilization for 4 h, and performed gene expression analysis by RNA sequencing. We identified 248 genes specifically regulated by both teratogens but not by FA. Further analysis of this gene set revealed 54 GO-terms related to the development of mesodermal tissues, distributed along the paraxial, intermediate, and lateral plate sections of the mesoderm. Gene expression regulation was specific to tissues and was observed for somites, striated muscle, bone, kidney, circulatory system, and blood. Stitch analysis revealed 47 regulated genes related to the RA-SP, which were differentially expressed in the various mesodermal tissues. These genes provide potential molecular biomarkers of mesodermal tissue and organ (mal)formation in the early vertebrate embryo.

Technology review of the Northern Bowen and Galilee basins

This paper reviews and summarises the work that has been conducted and the technology used in exploring and developing the Northern Bowen and Galilee basins in Queensland. It examines the methods operators have used in drilling, completing and testing wells through the varying stages of exploration, appraisal and development in the different parts of the basins. It examines all the work conducted in the Betts Creek Beds and Aramac Coal Measures throughout the Galilee Basin; the Moranbah Coal Measures, Rangal Coal Measures and Fort Cooper Coal Measures in the Moranbah area of the Bowen Basin; the Rangal Coal Measures, Burngrove Formation and Fairhill Formation in the Blackwater area; the conventional and coal seam gas developments in the Rolleston area, including the Bandanna Formation plays near Injune; and the Baralaba Coal Measures in the Moura area. Wells have been completed both open and cased hole with techniques including vertical wells, both with and without hydraulic fracturing and cavitation, as well as a variety of horizontal well designs including surface to inseam wells with vertical intercept wells and multiple lateral sections, chevron wells and both heel and toe intercepts. Operators have also implemented multiple wells on one pad. Throughout the Northern Bowen Basin, horizontal well drilling has been a key technology in commercial development. Generally, activities within the Galilee Basin have not progressed as far as the Bowen Basin, but nevertheless, horizontal wells are also emerging as a key technology.

ASSESSMENT OF TORSION RESISTANCE OF GLIDE PATH ROTARY INSTRUMENTS

NiTi endodontic instruments for glide path are the most susceptible to fractures inside the root canal, mainly as a result of high torsional stress. Objective: The present study investigated the resistance to torsion and angular deflection of instruments destined for the glide path: ProGlider #16.02; T-File #17.02 and the MK Life #16.02. Materials and methods: Thirty rotating NiTi glide path instruments (n=10) with 25mm lengths were selected. The torsion test was performed based on ISO 3630-01 (1992). Three millimeters from the tip of the instruments, it was attached to a small load cell by a lever arm connected to the torsion shaft. Torsional strength and angular deflection were evaluated. Fracture surfaces were examined by scanning electron microscopy with magnifications of 1000x and 5000x in the cross section, and 50x in the lateral section. Statistical analysis was performed using the Kruskal-Wallis H test, followed by the Down's post hoc test. Results: The ProGlider instrument showed greater torsional strength (p<0.05) compared to the T-File (p<0.05) and MK Life (p<0.05), respectively. However, the T-File showed greater angular deflection (p<0.05) than the other groups tested. Conclusion: It can be concluded that the ProGlider instrument presented greater torque for the fracture, while the T-File instrument presented greater angular deflection.
 

Mandibular Crowding: Diagnosis and Management-A Scoping Review.

Crowding is the most frequent malocclusion in orthodontics, with a strong hereditary tendency. It already occurs in pediatric age and is mainly hereditary. It is a sign of a lack of space in the arches, and is not self-correcting, but can worsen over time. The main cause of the worsening of this malocclusion is a progressive and physiological decrease in the arch perimeter. To identify relevant studies investigating the most common possible treatments for mandibular dental crowding, a comprehensive search of PubMed, Scopus and Web of Science was conducted encompassing the last 5 years (2018-2023) using the following MeSH: "mandibular crowding AND treatment" and "mandibular crowding AND therapy ". A total of 12 studies were finally included. An orthodontic treatment cannot ignore the concept of "guide arch", which concerns the lower arch, because of the objective difficulty in increasing its perimeter; the bone structure of the lower jaw is more compact than that of the upper one. Its expansion, in fact, is limited to a slight vestibularization of the incisors and lateral sectors that may be associated with a limited distalization of the molars. There are various therapeutic solutions available to the orthodontist, and a correct diagnosis through clinical examination, radiographs and model analysis are essential. The decision of how to deal with crowding cannot be separated from an overall assessment of the malocclusion to be treated.

Functional Segregation of the Human Cerebellum in Social Cognitive Tasks Revealed by TMS.

The role of the posterior cerebellum in social cognition is well established; however, it is still unclear whether different cerebellar subregions contribute to different social cognitive processes by exerting specific functions. Here, we employed transcranial magnetic stimulation (TMS) in male and female healthy humans to test the hypothesis of the existence of a medial-to-lateral gradient in the functional organization of the posterior cerebellum, according to which the phylogenetically newer cerebellar hemispheres are involved in tasks requiring higher-level social inferences whereas vermal/medial sectors are involved in basic perceptual emotional mechanisms. We found that interfering via TMS with activity of the medial cerebellum significantly impaired basic emotional recognition/discrimination. In turn, only TMS over the lateral cerebellum affected a task requiring recognizing an emotion considering the social context in which it was experienced. Overall, our data support the existence of a medial-to-lateral gradient in the posterior cerebellum, with medial sectors supporting basic emotion recognition and lateral sectors being recruited when the task taps on higher inferential processing/mentalizing. Interestingly, the contribution of the cerebellum in these different processes seems to be restricted to negative emotional stimuli.SIGNIFICANCE STATEMENT The cerebellum has been recently recognized as a critical component of the social brain, however, the functional topography of this structure in relation to social and emotional processes is still debated. By adopting a causative approach through the use of transcranial magnetic stimulation (TMS), the present study critically insights into the functional organization of the posterior cerebellum by testing the hypothesis of a medial-to-lateral gradient that reflects increasing complexity of social cognitive processes. Our findings demonstrate that lateral and medial cerebellar regions exert partially distinguishable functions in the social cognitive domain, with the medial cerebellum that mainly mediates basic perceptual emotional mechanisms while the lateral cerebellum, although supporting more basic functions, further subserves higher-level social operations.

Different Development Scenarios to Increase the Production Rates for Fauqi Oil Field Southeastern Iraq

The Fauqi field is located about 50Km North-East Amara town in Missan providence in Iraq. Fauqi field has 1,640 MMbbl STOIIP, which lies partly in Iran. Oil is produced from both Mishrif and Asmari zones. Geologically, the Fauqi anticline straddles the Iraqi/Iranian border and is most probably segmented by several faults. There are several reasons leading to drilling horizontal wells rather than vertical wells. The most important parameter is increasing oil recovery, particularly from thin or tight reservoir permeability. The Fauqi oil field is regarded as a giant field with approximately more than 1 billion barrels of proven reserves, but it has recently experienced low production rate problems in many of its existing wells. This study will concentrate on analyzing the Asmari reservoir as the main production reservoir in this field for an oil gravity of 18 API. While, well (FQ-8) has been selected as a pilot well to verify different development scenarios that could be taken to increase the reservoir production rate. The results show that both drilling lateral sections and performing the stimulation process in some reservoir intervals yield positive results to increase good productivity with different percentages. The lateral sections occasionally gave higher productivity than the stimulation process by (2-3) times.

Enabling High Precision Gradient Index Control in Subsurface Multiphoton Lithography.

Multiphoton lithography inside a mesoporous host can create optical components with continuously tunable refractive indices in three-dimensional (3D) space. However, the process is very sensitive at exposure doses near the photoresist threshold, leading previous work to reliably achieve only a fraction of the available refractive index range for a given material system. Here, we present a method for greatly enhancing the uniformity of the subsurface micro-optics, increasing the reliable index range from 0.12 (in prior work) to 0.37 and decreasing the standard deviation (SD) at threshold from 0.13 to 0.0021. Three modifications to the previous method enable higher uniformity in all three spatial dimensions: (1) calibrating the planar write field of mirror galvanometers using a spatially varying optical transmission function which corrects for large-scale optical aberrations; (2) periodically relocating the piezoelectrically driven stage, termed piezo-galvo dithering, to reduce small-scale errors in writing; and (3) enforcing a constant time between each lateral cross section to reduce variation across all writing depths. With this new method, accurate fabrication of optics of any index between n = 1.20 and 1.57 (SD < 0.012 across the full range) was achieved inside a volume of porous silica. We demonstrate the importance of this increased accuracy and precision by fabricating and characterizing calibrated two-dimensional (2D) line gratings and flat gradient index lenses with significantly better performance than the corresponding control devices. As a visual representation, the University of Illinois logo made with 2D line gratings shows significant improvement in its color uniformity across its width.

Development of the morphodynamics on Little Ice Age lateral moraines in 10 glacier forefields of the Eastern Alps since the 1950s

Abstract. Since the end of the Little Ice Age (LIA) in the middle of the 19th century, Alpine glaciers have been subject to severe recession that is enhanced by the recent global warming. The melting glaciers expose large areas with loose sediments in the form of lateral moraines, amongst other forms. Due to their instability and high slope angle, the lateral moraines are reworked by geomorphological processes such as debris flows, slides, or fluvial erosion. In this study, the development of the morphodynamics and changes in geomorphological processes on lateral moraines were observed over decades, based on a selection of 10 glacier forefields in the Eastern Alps. To identify geomorphological changes over time, several datasets of archival aerial images reaching back to the 1950s were utilized in order to generate digital elevation models (DEMs) and DEMs of difference. The aerial images were complemented by recent drone images for selected moraine sections, enabling a high-resolution analysis of the processes currently occurring. The results concerning the development of morphodynamics on lateral moraine sections are diverse: some slopes display a stagnation of the erosion rates, whereas the rates of one section increase significantly; however, the majority of the slopes show a decline in morphodynamics over decades but stay on a high level in many cases. In particular, moraine sections with high morphodynamics at the beginning of the observation period mostly show high erosion rates up until present-day measurements, with values up to 11 cm yr−1. These moraine sections also feature heavy gullying on their upper slopes. A correlation between the development of morphodynamics and the time since deglaciation could scarcely be established. In fact, the results instead indicate that characteristics of the lateral moraines such as the initial slope angle at the time of deglaciation have a significant influence on the later morphodynamics. These observations raise concerns as to whether the until now often conducted analyses based on the comparison of lateral moraine sections with different distances to the glacier terminus, assumed to represent varying time spans since deglaciation, can provide sound evidence concerning the process of stabilization.

Quantitative Long-Term Monitoring (1890–2020) of Morphodynamic and Land-Cover Changes of a LIA Lateral Moraine Section

Aerial photographs of the European Alps usually only reach back to the middle of the 20th century, which limits the time span of corresponding studies that quantitatively analyse long-term surface changes of proglacial areas using georeferenced orthophotos. To the end of the Little Ice Age, this leads to a gap of about 100 years. Using digital monoplotting and several historical terrestrial photographs, we show the quantification of surface changes of a Little Ice Age lateral moraine section until the late second half of the 19th century, reaching a total study period of 130 years (1890–2020). The (initial) gully system expands (almost) continuously over the entire study period from 1890 to 2020. Until 1953, the vegetation-covered areas also expanded (mainly scree communities, alpine grasslands and dwarf shrub communities), before decreasing again, especially between 1990 and 2003, due to large-scale erosion within the gully system. Furthermore, our results show that the land-cover development was impacted by temperature and precipitation changes. With the 130-year study period, we contribute to a substantial improvement in the understanding of the processes in the proglacial by analysing the early phase and thus the immediate response of the lateral moraine to the ice exposure.

Evaluations of Polyacrylamide Water-Based Drilling Fluids for Horizontal Drilling in the Shaly Wolfcamp Formation

Summary The Permian Basin, located in southeastern New Mexico and west Texas, is treated as the largest province of oil and gas production in the United States (US). The majority of hydrocarbon production from the Permian Basin is from the Wolfcamp shaly formation. Drilling horizontal and extended reached wells is continuously increasing day after day in the Permian Basin. Oil-based mud (OBM) is used to drill these horizontal wells for enhancing shale inhibition, reducing torque and drag, and supporting thermal stability of mud rheology. Due to environmental regulation for limiting use of OBM, the petroleum industry has tried to develop water-based fluid (WBF) that approaches the performance advantages of OBM. The main objective of this research is to formulate and develop WBF by using polyacrylamide anionic friction reducer (AFR) for drilling the lateral sections of horizontal wells in the shaly Wolfcamp formation. Shale inhibition, barite sagging, lubricity, and thermal stability of the formulated WBF with AFR will be studied to evaluate the developed WBF. Laboratory experiments were conducted to develop and evaluate the performance of the formulated WBF with AFR. The shale inhibition capabilities of the developed WBF with AFR were evaluated by using zeta potential, shale dispersion test, and immersion test. The results prove the capability of the formulated WBF with AFR to prevent both shale swelling and shale dispersion. AFR limits water penetrations to shale through encapsulation. The mixing procedures of AFR with WBF affect both the thermal stability of mud rheology and shale inhibition. Adding AFR to WBF helps to suspend weighting materials and mitigate barite sag. Besides, AFR decreases torque and drag by decreasing the coefficient of friction (COF). Furthermore, AFR supports enhanced stability of mud rheology with time up to 14 days at temperatures up to 180°F. The formulated WBF with AFR can be used for enhancing shale inhibition, supporting thermal and time stability of fluid rheology, improving lubricity, and minimizing barite sagging for drilling shaly Wolfcamp formations. This study presents a promising WBF to replace OBM to drill lateral sections in the Permian Basin.

Evaluation of Parent Well Depletion Effects on Fracture Geometry Based on Low-Frequency Distributed Acoustic Sensing in Hydraulic Fracture Test Site-2

Summary Low-frequency distributed acoustic sensing (LF-DAS) has recently received much attention for its ability to monitor fracture propagation at offset wells. Hydraulic Fracture Test Site-2 (HFTS-2), a Department of Energy–sponsored field-based research experiment, has acquired LF-DAS data sets during the stimulation of many horizontal wells in the Wolfcamp Formation of the Permian Basin. Over 100 stimulated stages with different completion designs in four horizontal wells were monitored by two horizontal offset wells and one vertical pilot hole with permanent fibers. The parent well depletion affected all four horizontal wells in almost half of their lateral section. Several studies have been performed on the acquired comprehensive data set. In this study, we apply our novel Green’s function-based inversion algorithm to calculate the fracture width of each stage and investigate the impact of parent well depletion on fracture geometry. The Green’s function-based inversion algorithm has been successfully applied to a few stages of field case studies. The Green’s function matrix was built based on linear elasticity theory (3D displacement discontinuity method) to relate the fracture openings with strain responses measured along the length of the fiber. This novel algorithm only relies on measured strain to solve fracture geometry at the monitoring well. Therefore, it is independent of the physics of the fracture propagation process and can be used to validate hydraulic fracture modeling results. Using our inversion algorithm, we can efficiently and quantitatively interpret LF-DAS data to provide information on fracture geometry and completion efficiency. We analyze more than 100 stages of the LF-DAS measurements obtained at the fiber wells B3H and B4H during B1H, B2H, and B4H stimulations. We apply our inversion algorithm for four data sets covering the stimulation of the abovementioned three wells. The fracture growth at stages in the parent well’s depleted zone is biased more toward upper formation and in the easterly direction. The fracture width at the stages in the parent well’s depletion zone is reduced compared to fracture widths at stages in the nondepleted zone irrespective of the monitoring well location relative to the treatment wells. This difference in fracture widths will affect the proppant distribution to a great extent, thereby affecting the effectiveness of the stimulation. We also illustrate the application of the inversion algorithm for stages that have both conventional fracture hits with “heart-shaped” signals as well as fracture reopening signals. Our inversion algorithm gives a reasonable estimate of the fracture width that aligns with the qualitative analysis of microseismic data sets and statistic summary of fracture hit numbers of HFTS-2. We believe that this quantitative study provides us with insights into the fracture geometry due to parent well depletion effects.

Three-Dimensional Analysis of the Thermal Behavior of Alumina-Water Nanofluid Inside Hexagonal and Octagonal Enclosed Domain

The current work focused on the study of the laminar and steady free convection of Aluminum Oxide / Water nanofluid inside cavities. Two different cavities have the same volume but different overall surface area and count of walls are studied. These cavities are heated differentially on the vertical square side walls which of identical area and dimensions for both cavities. The other vertical walls of these cavities have hexagonal and octagonal shapes. The first cavity has eight walls while the second has ten walls. The study accomplished for solid particles volume fraction and Rayleigh number ranges of (φ = 0.01, 0.03, 0.05) and (103 ≤ Ra ≤ 106). The study interested highly by the effect of the cavity geometry parameters including the lateral cross section, the height, the number of walls on the flow and heat transfer. Other flow parameters are recognized on the fluid flow and heat transfer fields like the nanoparticles volume fraction and the Rayleigh number. The results indicated that the surface area increase by means the additional walls has an observed effect on guiding the results. Where the octagonal cavity has better enhancement in heat transfer especially at (Ra=104 and 105). The percent increase in Nu over the hexagonal cavity is (0.6, 0.8, 0.7, 0.3) for the specified Ra range.

Ensemble learning application in multiplexed optical fibser sensor system for liquid level assessment

This paper presents the development and analysis of a sensor system based on multiplexed intensity variation sensors using a polymer optical fiber (POF). The sensor is based on a multiplexing technique from side-coupling of light emitting diodes (LEDs) with the sequential activation of the light sources. In this case, 20 sensors are developed from the side-coupling between the lateral section of the POF and each LED. The sensor system is embedded in a polydimethylsiloxane (PDMS) resin for encapsulation, chemical and mechanical protection of the sensors. The sensors sensitivities as a function of the refractive index and pressure are experimentally obtained. Then, the sensors are positioned inside an acrylic tank for the liquid level measurement and the water and oil identification. The tests using water and oil mixtures in the tank are performed to evaluate the possibility of measuring water and oil levels. To that extent, an ensemble learning algorithm using random forest (RF) is applied on the responses of the 20 sensors to obtain the level of each fluid. In addition, the algorithm's parameters of the RF approach are optimized using the minimization of root mean squared error (RMSE) as the objective. The dataset are divided into train and test samples with an additional dataset used as validation of the proposed RF-based regression model. Results show the feasibility of the proposed sensor system, where the mean errors for water and total levels are 0.14 cm and 0.08 cm, respectively. In the validation tests, a determination coefficient (R2) of 0.99 is obtained and a RMSE of 3.51 cm and 2.69 cm for water and total levels, respectively.

Fault Identification for the Purposes of Evaluating the Risk of Induced Seismicity: A Novel Application of the Flowback DFIT

Summary The existence of faults, pre-existing hydraulic fractures, and depleted areas can negatively impact the development of unconventional reservoirs using multifractured horizontal wells (MFHWs). For example, the triggering of fault slippage through hydraulic fracturing can create the environmental hazard known as induced seismicity (earthquakes caused by hydraulic fracturing). A premium has therefore been placed on the development of technologies that can be used to identify the locations of fault systems (particularly if they are subseismic) as well as pre-existing hydraulic fractures and depleted areas. The objective of this study is to develop a diagnostic tool to identify these conditions using DFIT-FBA, a modified diagnostic fracture injection test (DFIT) with flowback analysis (FBA). The time and cost efficiencies of the DFIT-FBA method in reservoir characterization provides an opportunity to conduct multiple field tests at a single point or along the lateral section of a horizontal well. An analytical model that considers critical processes and mechanisms occurring during DFIT-FBA was first developed herein. The results of analytical modeling demonstrate that reservoir heterogeneities (i.e., faults) can be identified either by implementing multiple cycles of the DFIT-FBA method at a single point or by applying multiple DFIT-FBAs at different points along the lateral section of a horizontal well or at different wells. The analytical model is then verified using a fully coupled hydraulic fracture, reservoir, and wellbore simulator, and flowing pressure responses in the presence of a fault are illustrated. The practical application of the proposed method is demonstrated using DFIT-FBA field examples performed in a tight reservoir. Analysis of the field examples leads to the conclusion that a fault likely occurs near the toe of the horizontal lateral. This finding was confirmed by other field information and provides the opportunity to modify the main-stage hydraulic fracturing design to avoid induced seismicity events.

Machine learning improves the accuracy of graft weight prediction in living donor liver transplantation.

Precise graft weight (GW) estimation is essential for planning living donor liver transplantation to select grafts of adequate size for the recipient. This study aimed to investigate whether a machine-learning model can improve the accuracy of GW estimation. Data from 872 consecutive living donors of a left lateral sector, left lobe, or right lobe to adults or children for living-related liver transplantation were collected from January 2011 to December 2019. Supervised machine-learning models were trained (80% of observations) to predict GW using the following information: donor's age, sex, height, weight, and body mass index; graft type (left, right, or left lateral lobe); computed tomography estimated graft volume and total liver volume. Model performance was measured in a random independent set (20% of observations) and in an external validation cohort using the mean absolute error (MAE) and the mean absolute percentage error and compared with methods currently available for GW estimation. The best-performing machine-learning model showed an MAE value of 50 ± 62 g in predicting GW, with a mean error of 10.3%. These errors were significantly lower than those observed with alternative methods. In addition, 62% of predictions had errors <10%, whereas errors >15% were observed in only 18.4% of the cases compared with the 34.6% of the predictions obtained with the best alternative method ( p < 0.001). The machine-learning model is made available as a web application ( http://graftweight.shinyapps.io/prediction ). Machine learning can improve the precision of GW estimation compared with currently available methods by reducing the frequency of significant errors. The coupling of anthropometric variables to the preoperatively estimated graft volume seems necessary to improve the accuracy of GW estimation.

Elastomer-Embedded Multiplexed Optical Fiber Sensor System for Multiplane Shape Reconstruction

This paper presents the development and application of a multiplexed intensity variation-based sensor system for multiplane shape reconstruction. The sensor is based on a polymer optical fiber (POF) with sequential lateral sections coupled with a flexible light-emitting diode (LED) belt. The optical source modulation enables the development of 30 independent sensors using one photodetector, where the sensor system is embedded in polydimethylsiloxane (PDMS) resin in two configurations. Configuration 1 is a continuous PDMS layer applied in the interface between the flexible LED belt and the POF, whereas Configuration 2 comprises a 20 mm length PDMS layer only on each lateral section and LED region. The finite element method (FEM) is employed for the strain distribution evaluation in different conditions, including the strain distribution on the sensor system subjected to momentums in roll, pitch and yaw conditions. The experimental results of pressure application at 30 regions for each configuration indicated a higher sensitivity of Configuration 1 (83.58 a.u./kPa) when compared with Configuration 2 (40.06 a.u./kPa). However, Configuration 2 presented the smallest cross-sensitivity between sequential sensors (0.94 a.u./kPa against 45.5 a.u./kPa of Configuration 1). Then, the possibility of real-time loading condition monitoring and shape reconstruction is evaluated using Configuration 1 subjected to momentums in roll, pitch and yaw, as well as mechanical waves applied on the sensor structure. The strain distribution on the sensor presented the same pattern as the one obtained in the simulations, and the real-time response of each sensor was obtained for each case. In addition, the possibility of real-time loading condition estimation is analyzed using the k-means algorithm (an unsupervised machine learning approach) for the clusterization of data regarding the loading condition. The comparison between the predicted results and the real ones shows a 90.55% success rate. Thus, the proposed sensor device is a feasible alternative for integrated sensing in movement analysis, structural health monitoring submitted to dynamic loading and robotics for the assessment of the robot structure.

The magnitude of stress concentration of I-beam with web opening because of lateral-torsional buckling effects

PurposeIt is generally known that the perforated section such as the castellated section is good to sustain distributed loads but inadequate to sustain highly concentrated loads. Therefore, it is possible to design the opening in a different arrangement of web opening to achieve section efficiency, thus improving the strength and torsional behaviour of the section with web opening. This study aims to focus on the finite element analysis of I-beam with and without openings in steel section dominated to lateral-torsional buckling behaviour.Design/methodology/approachIn this work, the analysis of different sizes, shapes and arrangements of web opening is performed by using LUSAS application to conduct numerical analysis on lateral-torsional buckling behaviour. This involves three diameter sizes of web opening, five types of opening shapes and two criteria of the model.FindingsThe section with c-hexagon web opening was placed about 200-mm centre to centre and 100-mm edge distance, contribute to 7.26% increase of buckling capacity. For the section with 150-mm centre to centre and 50-mm edge distance, the occurrence of local buckling contributes to decrease of lateral buckling section capacity to 19.943 kNm, where pure lateral-torsional buckling mostly occurred because of prevented section. Besides that, the web opening diameter was also analysed. The web crippling was observed because of the increase of opening diameter from 0.67 to 0.80 D.Originality/valueThis contributes to a decrease in buckling capacity as figured in the contour of the deformed shape. For Model 1, an increase of buckling capacity (31.46%) is observed when the opening diameter are changed from 0.67 to 0.80 D.