bluuebunny/crossref_metadata_2025 huggingface dataset:
Instantaneous Reaction and Vibration Suppression Using Two-Degree-of-Freedom Admittance Control with H∞ Feedback Controller in Surgical Training Simulator with Chiseling Operation
Authors: Masuyama Kentaro , Noda Yoshiyuki , Ito Yasumi , Kagiyama Yoshiyuki , Ueki Koichiro ,   Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan,   Faculty of Engineering, University of Yamanashi  4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan,   Faculty of Medicine, University of Yamanashi  1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
Published: August 2022

Surgical training simulators with virtual reality have been developed to enable surgeons to efficiently acquire and improve their surgical skills. In hard tissue surgery, the surgeon uses a chisel and mallet to cut a bone or tooth with large and instantaneous forces. In the previous study by present authors, to represent the force sensation of the cutting operation in the virtual training simulator, we constructed the force display device using the ball-screw mechanism to obtain high stiffness and display the large force. Additionally, we applied the two-degrees-of-freedom (2DOF) admittance control to react instantaneously to the impact force by pounding with the mallet. The feedback controller of the 2DOF admittance control is required to increase the high-frequency gain for improving the responsiveness of the force display device. However, the vibrational mode of the force display device can be excited by increasing the controller gain. Therefore, this study develops the design approach of the feedback controller using the H∞ control in the 2DOF admittance control system, which can be systematically constructed to reduce the vibrational mode and react instantaneously in the force display device. The efficacy of the proposed force display control system is verified through the virtual experience of the free movement and the hard contact operations.
Osseointegration and Remodeling of Mineralized Bone Graft Are Negatively Impacted by Prior Treatment with Bisphosphonates
Authors: Cohen D. Joshua , Lohmann Christoph H. , Scott Kayla M. , Olson Lucas C. , Boyan Barbara D. , Schwartz Zvi
Published: August 2022

Background:

Bisphosphonates limit resorption by inhibiting osteoclast formation and activation. They are removed during preparation of demineralized bone matrix (DBM) particles, but it is not known if osteogenesis and incorporation of mineralized bone allografts from patients treated with oral bisphosphonates are affected in vivo.

Methods:

Human block allografts from 3 bisphosphonate-treated donors and 3 age and sex-matched control donors who had not received bisphosphonates were obtained (Musculoskeletal Transplant Foundation); one-half from each donor was demineralized. In the first study, 3 × 2-mm mineralized and demineralized cylindrical grafts were implanted bilaterally in the femoral metaphysis of 56 rats. In the second study, samples from each group were pooled, prepared as particles, and implanted bilaterally in the femoral marrow canal of 24 rats. Osseointegration, defined as native bone in contact with allograft, was assessed at 10 weeks by micro-computed tomography (CT) and histomorphometry.

Results:

Micro-CT showed greater bone volume in sites treated with demineralized samples compared with the control mineralized and bisphosphonate-exposed mineralized samples. More new bone was generated along the cortical-endosteal interface compared with mineralized samples. Histology showed significantly less new bone in contact with the mineralized bisphosphonate-exposed allograft (10.4%) compared with mineralized samples that did not receive bisphosphonates (22.8%) and demineralized samples (31.7% and 42.8%). A gap was observed between native bone and allograft in the bisphosphonate-exposed mineralized samples (0.50 mm2). The gap area was significantly greater compared with mineralized samples that did not receive bisphosphonates (0.16 mm2) and demineralized samples (0.10 and 0.03 mm2).

Conclusions:

Mineralized allografts were osseointegrated, but not remodeled or replaced by living bone, preventing full regeneration of the bone defect. Prior treatment of the donor with bisphosphonates affected osteogenesis, preventing osteointegration and remodeling of the allograft into the regenerating bone.

Clinical Relevance:

Clinical use of mineralized allografts from patients who had received bisphosphonate therapy needs to be evaluated; in this animal model, such grafts were not integrated into the host bone or remodeled, and full regeneration of the bone defects was prevented.
Pain Catastrophizing Influences Preoperative and Postoperative Patient-Reported Outcomes in Adolescent Idiopathic Scoliosis
Authors: Ramo Brandon A. , Collins-Jones Teresa L. , Thornberg David , Klinkerman Lydia , Rathjen Karl , Jo Chan-Hee
Published: August 2022

Background:

Patients with adolescent idiopathic scoliosis (AIS) often report chronic back pain; however, there is inadequate research on psychological factors associated with pain in this patient population. Pain catastrophizing, a psychological factor that describes a pattern of negative thoughts and feelings about pain, has been associated with poorer responses to medical treatment for pain. The purpose of this study was to report the prevalence of pain catastrophizing in the AIS population and assess its relationship with preoperative and postoperative self-reported outcomes.

Methods:

In this prospective cohort study of consecutive patients undergoing posterior spinal fusion (PSF) for AIS, patients experiencing clinically relevant pain catastrophizing, defined as a Pain Catastrophizing Scale for Children (PCS) score in the 75th percentile or higher, were compared with patients with normal PCS scores. Preoperative and 2-year postoperative Scoliosis Research Society Society Questionnaire-30 (SRS-30) scores were correlated with the preoperative PCS score.

Results:

One hundred and eighty-nine patients underwent PSF for AIS, and 20 (10.6%) were considered to be experiencing pain catastrophizing. Despite comparable demographic and radiographic variables, pain catastrophizing was associated with significantly lower preoperative scores than were found in the normal-PCS group in all SRS-30 domains, including pain (2.98 versus 3.95; p < 0.001), appearance (2.98 versus 3.48; p < 0.001), activity (3.51 versus 4.06; p < 0.001), mental health (3.12 versus 4.01; p < 0.001), and total score (3.18 versus 3.84; p < 0.001), except satisfaction (3.72 versus 3.69; p > 0.999). At 2 years, the pain catastrophizing group experienced significant improvement from their preoperative scores in most SRS-30 domains, including a large clinically relevant improvement in pain (from 2.98 preoperatively to 3.84 postoperatively; p < 0.001) and the total score (from 3.18 to 3.85; p < 0.001), but continued to have lower scores than the normal-PCS group for pain (3.84 versus 4.22; p = 0.028) and the total score (3.85 versus 4.15; p = 0.038). Receiver operating characteristic (ROC) curve analysis indicated that an SRS-30 pain score of <3.5 has good sensitivity for predicting pain catastrophizing (PCS ≥75th percentile).

Conclusions:

In this cohort, patients with AIS who exhibited pain catastrophizing experienced significant improvement in self-reported health 2 years after PSF. However, they did not have the same levels of self-reported health as the normal-PCS group. Pain catastrophizing may be identifiable by lower preoperative SRS-30 pain scores.

Level of Evidence:

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
Çalışanların Sergilediği Yeşil (Çevreci) Davranışlara Yönelik Nitel Bir Araştırma
Authors: TARTAN SELCUK Evrim , KERSE Gökhan
Published: August 2022

Çevresel sorunların her geçen gün artması bugünü olduğu kadar geleceği de tehdit etmekte, bu nedenle de çözüm sürecinde toplumun her kesimine görev düşmektedir. İşletmeler bu sorunların çözümü için aktif rol oynayan ve görevler üstlenen taraflardan birisidir. İşletmeler çevresel sorunların çözümü için tüm süreçlerini sürdürülebilirlik bakış açısıyla ele almalı ve çalışanlarının işyerinde çevreci davranışlar sergilemesini teşvik etmelidir. Bu nedenle çalışanların çevreye ve çevresel sorunlara yönelik algılarının anlaşılmasına, çalışanların sosyal hayatlarında ve işyerlerinde hangi davranışları çevresel duyarlılıkla sergilediğinin belirlenmesine ve örgütlerin çalışanlarını çevreci davranışlara yöneltmek için neler yaptığının anlaşılmasına ihtiyaç duyulmaktadır. Bu çalışmanın temel amacı çalışanların işyerlerinde sergiledikleri çevreci davranışların neler olduğunun açığa çıkarılması, bu davranışların sektörel farklılıklar gösterip göstermediğinin, sosyal hayatta sergilenen davranışlar ile iş hayatında sergilenenler arasında tutarlılık olup olmadığının, işletmelerin kurumsal politikalar ile bu davranışları teşvik edip etmediğinin açığa çıkarılmasıdır Araştırmada nitel yöntem tercih edilmiş, olgubilim deseninde gerçekleştirilerek Karaman ilinde farklı sektörlerde çalışan bireyler ile yüz yüze görüşmeler yapılmıştır. Çalışma sonucunda çalışanların sergiledikleri yeşil davranışlar belirlenerek sektörel farklılıklar ortaya konulmuş, çalışanların yeşil davranışlara ilişkin bilgilerinin sınırlı, işletmelerin uygulamalarının ise yetersiz olduğu sonucuna ulaşılmıştır.
Elektrikli Otomobil Satın Alma İstekliliğini Etkileyen Faktörler: Konya İli Örneği
Authors: USLU Hakan , DEMİREL Onur
Published: August 2022

Avrupa’da doğup dünyaya yayılan otomotiv sektörü, üretime, istihdama ve dış ticarete yaptığı katkıların yanında demir-çelik, cam, elektronik ve yazılım gibi sektörler için de önem arz etmektedir. Bu bağlamda, otomotiv sektörü hem teknolojik gelişmenin katalizörü hem de ekonomiye yaptığı katkılar dolayısıyla lokomotif bir sektör olarak kabul edilmektedir. Buna ek olarak otomobil kullanımı günümüz dünyasında bir ihtiyaç olarak kabul edilmektedir. Çalışmada Konya ili özelinde tüketicilerin elektrikli otomobil kullanımına yönelik tutumları araştırılmıştır. Bu amaçla güdümlü örneklem seçim tekniğinden faydalanılarak 222 online anket gerçekleştirilmiştir. Elde edilen veriler Nlogit 4.0 paket programı kullanılarak Logistik Regresyon (Logit) modeli ile analiz edilmiştir. Çalışma sonucunda gelir, haftalık yapılan km, elektrikli otomobil hakkında bilgi sahipliği, elektrikli otomobillerin prestijli olduğu ve ilk yerli elektrikli otomobil olacak TOGG’ un talebi olumlu etkileyeceği değişkenlerinin istatistiksel olarak anlamlı ve elektrikli otomobil satın alma isteği üzerinde pozitif etkiye sahip olduğu tespit edilmiştir. Bu bağlamda elektrikli otomobil satışlarının artması için; hanehalkı gelirini art(tırıl)ması, elektirikli araç menzilinin arttırılması, elektrikli araçlar hakkında bilgi düzeyinin arttırılması, elektrikli araçların reklamlarına teşvik verilerek prestijinin desteklenmesi aracılığıyla tüketici yöneliminin arttırılması ve TOGG’ un seri üretiminin gerçekleştirilerek halkın ulaşabileceği model ve fiyatların sunulması gerekmektedir. Yine elektrikli araçlar için maddi (vergi teşviki, ücretsiz park vb.) ve maddi-olmayan (özel şeritler vb.) teşvikler uygulanmalıdır.
İşkoliklik ve Bireysel Mutluluk Arasındaki İlişkinin Sağlık Çalışanları Açısından İncelenmesi: Bir Kamu Araştırma ve Uygulama Üniversite Hastanesinde Uygulama
Authors: ERKAN Burcu , CEZLAN Esra Çiğdem
Published: August 2022

Son zamanlarda işkoliklik ve iş hayatında mutluluk kavramları üzerinde en çok araştırma yapılan konulardan olmuştur. Bu araştırma; Isparta ilinde faaliyet gösteren bir kamu araştırma ve uygulama hastanesinde çalışan sağlık çalışanlarının, bireysel mutluluk ve işkoliklik ilişkisini incelemek amacıyla yapılmıştır. Araştırma kapsamında çalışmaya katılmayı gönüllü olarak kabul eden 500 sağlık çalışanına anket uygulaması yapılmıştır. Çalışmada veri toplama aracı olarak “Oxford Mutluluk Ölçeği” ve “Duwas İşkoliklik Ölçeği” kullanılmıştır. Yapılan çalışmada sürekli değişkenlerin normallik varsayımları Shapiro Wilk’s testi ve Kolmogorov-Smirnov testi, varyans homojenlikleri Levene’s Testi ile incelenmiştir. Verilerin normal dağılmadığı iki düzeyli karşılaştırmalar için Mann-Whitney U testi ve üç düzeyli kıyaslamalar için Kruskall Wallis testleri kullanılmıştır. İşkoliklik ölçeğinin ortalaması 43,56±9,70, bireysel mutluluk ölçeğinin ortalaması ise 87,07±9,69 olarak bulunmuştur. Bireysel mutluluk ve işkoliklik ölçeği arasındaki korelasyon incelendiğinde, aralarında pozitif zayıf istatistiksel olarak anlamlı bir ilişki olduğu görülmüştür (r=0,323; p<0.001). Buna göre; işkolikliğin alt boyutu olan kompulsif çalışma için çalışma birimi ve cinsiyet değişkenlerinin anlamlı bir farklılık gösterdiği saptanmıştır. Sağlık çalışanlarına bireysel mutluluk açısından bir değerlendirme yapıldığında; cinsiyet değişkeninde anlamlı bir farklılık bulunmuştur.
Technical assessment of the Old, Mississippi, Atchafalaya, and Red (OMAR) Rivers : Red and Atchafalaya Rivers AdH model
Authors: Leech James
Published: August 2022

The Red River, Atchafalaya River, and the Old River Control Complex (ORCC) Outflow Channel Adaptive Hydraulics two-dimensional depth averaged sediment model (AdH-2D-SED) was used to evaluate the short-term and system-wide sedimentation effects of modifying the operation schedule at ORCC. The changes evaluated were increasing and decreasing the percentage of flow that is diverted to the Atchafalaya River from the Mississippi River at the ORCC and modifying the distributions through four ORCC structures. Sedimentation effects for several operation scenarios were compared to a Base condition for each water year that represented the existing operation protocols. Four dredging scenarios were developed and analyzed. Additionally, two structure options were developed and analyzed. The scenario analyses presented in this report are intended to identify large trends and to make gross assessments of the potential impacts of various proposed operational changes to the ORCC.
Thermobaric Conditions for Exhumation of Ti-clinohumite Garnetites of the Kokchetav Subduction-Collision Zone (Northern Kazakhstan)
Authors: Selyatitskii A.Yu. , Reverdatto V.V.
Published: August 2022

—A new variety of Ti-clinohumite garnetites (‘garnet peridotites’) of the diamond-bearing Kumdy Kol terrane in the Kokchetav massif has been studied. An ultrahigh-pressure phase, Ti-chondrodite, orthopyroxene and contrast-zoned garnets of retrograde zoning have been found in these rocks for the first time. Ti-chondrodite and orthopyroxene were not described in these rocks earlier, and garnet composition was supposed to be homogeneous. Based on the character of chemical zoning of garnet and orthopyroxene, the peak and three retrograde parageneses for these minerals have been distinguished. Using the garnet–orthopyroxene geothermobarometry, for the Kumdy Kol terrane, based on the quantitative P–T estimates of Ti-clinohumite garnetites, a detailed retrograde P–T trend has been constructed for the first time; this trend includes the UHP peak stage (55–57 kbar, 1075–1120 °С), and three stages of retrograde metamorphism under UHP (32 kbar, 830 °С), HP (21 kbar, 750 °С), and MP (12 kbar, 740 °С) conditions. For the Kumdy Kol terrane this is the most detailed Р–Т trend indicating subisothermal decompression during crustal rock exhumation from the mantle depths (~170 km) to the lower-crust conditions (~36 km). The above-mentioned mineralogical findings allowed reconstructing all the described metamorphism stages, using the same rock and various generations of the same minerals (garnet and orthopyroxene) formed at different stages of tectono–metamorphic evolution of the Kumdy Kol terrane. Preservation of the relics for mineral zoning of the early metamorphic stages seemed to be due to high uplift velocities resulted in rapid decrease in P–T parameters and short duration of regressive metamorphism. The virtually complete identity of the obtained P–T trend for the Kumdy Kol terrane and the P–T trend for the Barchi terrane supports the idea of the common tectono–metamorphic evolution of the whole western (diamond-bearing) part of the Kokchetav massif.
On the Creation of a Digital Permanently Operating Structural Model for the Sedimentary Cover of the West Siberian Petroleum Province
Authors: Sidorov A.A.
Published: August 2022

The paper presents some results of the development of a digital permanently operating structural and geological model (implemented at the Autonomous Institution of the Khanty-Mansiysk Autonomous District–Yugra V.I. Shpilman Research and Analytical Center for the Rational Use of the Subsoil) for the area of central West Siberia and important aspects that need to be considered in implementation practice. The methodological challenges of the variational-grid mapping method and its application include problems such as finding an optimal computational grid and using heterogeneous input information for mapping key seismic horizons. An effective method is considered for using seismic data with uncorrected misties in geological mapping based on corrections for derivatives of the desired function along the seismic profile direction (i.e., seismic surface shape). Special attention is paid to a priori information when mapping stratigraphic boundaries with poorly correlated seismic sections. The conformal thickness model linking geometry of the mapped surface with the structural framework of the two reference boundaries has been tested on the construction of regional structural and geological models for the Jurassic interval of the cross section of West Siberia. The model modification can also be applied to mapping clinoform formations. Given the scale and nontrivial tasks of regional mapping, the issues related to setting up the computing workflow are considered in detail: algorithmization, programming protocols, and automation. In the light of the accentuated relevance of the development of specialized software, the GST (Geo-Spline Technology) software product is considered, with the digital structural framework of the region implemented therein. This resulted in a permanently operating model, since the hierarchical object-oriented approach implemented in GST ensures a complete protocol that integrates computational procedures and data flows, as well as automation of model recalculation. The structural framework serves as the basis for mapping physical properties and parameters, assessment of the region resource potential, and r study of other aspects. The proposed model being not conclusive, it offers rich opportunities for revision and refinement as to the area size (geological model domain), level of detail, database enlargement, thereby determining the directions of further development of the digital structural framework.
Experimental Comparison of Two Downhole Separators in Boosting Artificial Lift Performance
Authors: Olubode Michael , Osorio Laura , Karami Hamidreza , McCoy Jim , Podio Tony
Published: August 2022

Gas evolution and expansion are natural phenomena in petroleum wells. However, gas is detrimental to pumping artificial-lift (AL) systems, causing incomplete pump fillage and reduced pump efficiency. Pumping AL systems may also be involved in high GLR applications for gas well deliquification. It then becomes essential to separate the gas before the pump's intake in these applications to preserve the life of the pump. Various downhole separators with questionable efficiencies are available today. In this study, an automated experimental separation facility is presented and applied to test the efficiency of two downhole separators. The setup includes a 31-ft horizontal section followed by a 27-ft vertical section that houses the separator. The performance of the separators is evaluated at different air (34 - 215 Mscf/d) and water rates (17 - 867 BPD). The multiphase-flow loop is equipped with pressure transducers and control valves for effective flow control. Data acquisition and process control are performed using LabVIEW™.

A newly designed packer-type centrifugal downhole separator is evaluated over a wide range of flow rates and compared to a basic gravity-type separator without the centrifugal part. The performance and outlet flow stability of the separators are compared. Liquid separation efficiency is a measure of the fraction of the inlet liquid produced at the tubing return line. Output flow stability is measured by looking at the ratio of standard deviation over the average flow rate. Separation efficiency is close to ideal (100%) for liquid rates up to 500 BPD for both separators. The efficiency slightly decreases at higher liquid rates, but stays above 80%. This decline in efficiency is more noticeable for the gravity separator compared to the centrifugal, and it is sharper for higher gas rates (over 300 SCF/STB). The centrifugal separator provides a more stable output flow rate with less fluctuations compared to the gravity type. Various flow patterns in the separator outlet and the casing are visualized and recorded.

With declining rates of production from oil fields and the need to de-liquefy gas wells, efficient artificial lift is necessary. This system provides a unique and novel tool to simulate the dynamics of flow in wellbores and identify the best tools to improve the efficiency.
Impacts of Well Geometry and Gas Lift on Flow Dynamic and Production of Unconventional Horizontal Wells
Authors: Tran Ngoc Lam , Orazov Baurzhan , Karami Hamidreza
Published: August 2022

Horizontal wells have brought significant improvements in production of unconventional reservoirs. However, one of the main debates in completion optimization lies on the effects of horizontal well geometry throughout a well's life. On the other hand, gas lift installations are becoming widespread to leverage the depletion in pressure and flow rate. Transient multiphase simulation allows physics-based modeling of flow performance in horizontal wells without or with gas lift application. The objective of this work is to use these simulations and provide a qualitative analysis of well geometry effects on slugging and production of horizontal wells.

This study uses OLGATM as a transient multiphase simulator to mimic a horizontal well's production over 36-hour time periods. The well produces through a 2-7/8″ ID tubing with MD of 10000 and TVD ranging from 4900 ft to 5100 ft, depending on the lateral geometry. The lateral section has a deviation angle range of 88-92°, with three geometries simulated, including toe-up, toe-down and horizontal. For each geometry, two cases are simulated: one without any undulations and one with random undulations along the lateral section. A realistic decline curve equation is used to estimate the decline in reservoir pressure throughout the well's life and simulate its production for 6 years, including early life with higher rates and late life of the depleted well. Gas lift is also installed late life to analyze its impacts on flow.

The simulation results offer valuable insight into well geometry effects throughout a well's life. At early life, slugging is minimal and production rates are close for all the geometries, with simulations favoring the toe-up well by a small margin. However, the geometry effects increase significantly as the well depletes. Slugging becomes more severe in almost all toe-up and horizontal cases, causing large fluctuations in pressure and reduction in total production. Undulations in toe-up help reduce the slugging severity and slightly improve the production. Gas lift proves to help reduce the back pressure and slugging severity downstream of the valve, and significantly improve production. The study of well geometry and its impacts on production design remains to be limited. Therefore, this study is a unique effort to provide a guideline and optimize well configuration and artificial lift design.
Gas Lift Valve Bellow Protection from High Injection and Dome Pressure
Authors: Salihbegovic Zlatko
Published: August 2022

Bellows are mechanical devices used to compensate linear, thermal, or angular movement/expansion. Said bellows can be manufactured in different shapes, sizes, using different materials. One typical example of bellows application is in pipelines to compensate for thermal expansion between solid points. In oil and gas industry, among other applications, bellows are used in gas lift valves as a slidable seal between Nitrogen charged in valve dome section and injection pressure. Currently, only two nominal bellow sizes are used in gas lift application, one Inch and one and a half Inch. Examples of gas lift valves using one-and three-quarter Inch were manufactured but are not widely used. However, as manufactured bellows having very thin walls are not well suited for pressures higher than 200 PSI, depending on bellow size, shape and material used. To withstand much higher pressures bellows are being crimped, method that compresses bellow to shorter length which increases bellow overall mechanical toughness. In addition, bellows in gas lift valves must be pressure balanced inside and outside as much as possible to withstand high pressure up to 2500 PSI. By design bellows used in typical gas lift valves feature internal seal that is engaged once valve is in fully open position and bellow is expanded trapping "noncompressible" fluid usually silicone oil of different density. Nitrogen in gas lift valve is in direct contact with silicone oil and penetrates/dissolves into oil in form of bubbles. Being so called permanent gas Nitrogen never liquifies and always remain in gaseous state at any pressure no matter how high. This renders so called "noncompressible" fluid compressible and it does not prevent bellow damage when exposed to extremely high injection pressures. This theory used for decades in oil and gas industry is wrong resulting in premature bellow failures. This paper analyses existing gas lift designs and offers solution for problems specified herein.
New Integrated Approach to ESP Management - Successful Strategy to Optimize Well Production and ESP Run Life
Authors: Spagnolo Salvatore , Pignotti Eleonora , Scarso Marco , Cappuccio Pasquale , Pilone Salvatore , Valente Alberto , Gonzalez Zamora Mariangela , Ciavarro Lucio
Published: August 2022

Our analysis identified specific best practices to help Production Engineers improve the performance of the ESP system. We demonstrated how, by closely monitoring the interactions between injected chemicals and pump control parameters, the ESP run life can be increased and total cost of ownership reduced. ESP are used in depleted reservoirs, but failure rate poses economical limitations when rig availability is low and workover costs are high. To minimize the deferred production, we devised a comprehensive strategy for de-risking ESP operations with ad-hoc chemical treatment. Many variables are analyzed in literature to increase ESP run life. However, they are often treated standalone. We evaluated previous studies conducted in this field, both at downhole level and surface production facilities. We focused our quantitative analysis on the interaction between reservoir fluids and ESP system to identify detectable signatures on pump control parameters. We continuously monitored operation of pumps at field level through real time data and identified distinctive anomalies in specific wells. We ran software simulations to evaluate likelihood and type of scale deposition downhole. We selected ad-hoc chemical treatment and accurately measured impact on ESP control parameters. Initially we observed a decrease in delta pressure (pump intake vs. pump discharge) in a well, a trend that was determined by possible pump plugging. The team decided to collect field samples of the produced fluids. A chemical downhole model was calculated through software simulation, then an ad-hoc chemical treatment was selected for the specific application. The team then iterated the solution in the field using additives for: i) inhibiting formation of further deposits; ii) removing existing scale deposits at ESP level. With rigorous evaluation of the new pump conditions through remote live monitoring and continuous adjustment of chemical treatment, the well showed a positive gain of delta pressure indicating the effectiveness of the solution. In the following months, well tests were conducted on site with test separators to collect actual data on the additives used. This allowed the team to fine-tune the long-term treatment program after further reducing the chemical dosage to optimize OPEX. Our study identified specific variables that Production Engineers must analyze when operating ESP in high-risk/high-return projects. Also, we identify a general methodology to promptly intervene in case of erratic pump behavior. The paper describes for the first time what a comprehensive production solution can do in increasing ESP run life while restoring production in complex wells prone to scale deposition. Software analysis and continuous data collection/interpretation from downhole pumps were key aspects to mitigate risk
A Data-Driven Approach to Predict the Critical Gas Flow Rate in Gas Wells
Authors: Rahmati Ehsan , Sim William Michael Nathan , Moffett Ross Edward , Pond Christopher Burke , Hingerl Ferdinand Franziskus
Published: August 2022

Liquid loading is a major factor limiting the production of gas wells. Liquid loading starts when the gas production rate does not provide sufficient transport energy to lift the liquid out of the well. The downhole liquid accumulation imposes an additional hydrostatic backpressure on the formation and decreases the production capacity of the well. This paper presents a data-driven model to predict the minimum gas rate required to lift the liquids out of the well.

A dataset consisting of 394 horizontal plunger-lift gas wells was used to train the data-driven model. A total of 32,292 points of liquid loading onset were found in the dataset and the corresponding gas flow rate was labelled as the target. Principal Component Analysis and Mutual Information Regression were performed to choose twelve most influential features on the critical gas flow rate (target). A model group consisting of three different machine learning algorithms and ten different data preprocessing steps was trained on the dataset. The most accurate model in the group was chosen to be the critical gas flow rate model.

Results showed that the data-driven critical gas flow rate model predicts the critical flow rate with R2 scores of 0.97 and 0.90 for train and test datasets, respectively. Also, the model results were compared to a few well-known empirical correlations in the literature (Turner, Coleman, Belfroid, Wang, Nagoo, and Shekhar equations). Results confirmed that the data-driven model has the highest agreement with the Belfroid model in comparison with the other equations. Next, an unsupervised learning method was used to modify the Belfroid equation. The modified correlation was proposed as a simple engineering tool to calculate the critical flow rate with higher accuracy in comparison with other correlations studied. It was observed that the Belfroid model underestimates the critical flow rate by around 32% and 5.2% for wells with tubing pressures lower than 300 Psig and higher than 300 Psig, respectively.

Most of the current critical flow rate models are based on two theories to explain the onset of liquid loading, droplet reversal and film reversal. Yet, the liquid loading mechanism is unknown due to the complexity of dynamic interactions between the reservoir and wellbore. Besides, most of the current models have their own limiting assumptions. This study provides a model that avoids unlikely theories or unrealistic assumptions and utilizes one of the biggest datasets of wells.
Automated ESP-Lifted Well Startup Using Model Predictive Control: Introduction of the Algorithm and Field Tests Results
Authors: Sadowska Anna , Steenson Leo , Williams Michael , Meredith Andrew , Chong Jonathan , Anderson Jeffery , Kelly Dwayne
Published: August 2022

The start of an electric submersible pump (ESP) is the most dynamic event in the life of the ESP, and one that has been shown to be the main contributor to the premature failure of the ESP; yet it is clearly unavoidable. This article introduces an algorithm comprising of a model-predictive controller and a moving horizon estimator for automating the well startup. Objectives and constraints related to the startup are considered for the whole well system, including the reservoir, the ESP, the tubing etc. A lumped-parameter model is established to model the fluid dynamics in the system.

The estimator recalibrates the model and provides estimates (virtual measurements) in lieu of unavailable physical measurements. The operating sequences for the ESP and choke are then updated step-by-step by the controller, considering the model of the system, the startup objectives and constraints, and the measured feedback information from the wellbore gauges.

The startup algorithm was implemented on a field edge device and deployed to a well in the Permian Basin. The algorithm executed two successful startups. A model recalibration was conducted before the second startup which improved the accuracy of setpoint tracking.
Prediction of Viscosity Correction Factors for ESP in Viscous Applications
Authors: Sheth Ketankumar Kantilal , de Long Robert Charles
Published: August 2022

Electric submersible pumps (ESPs) are currently being tested in the service company's newly built viscous lab testing loop; whereby, the viscous performance of each pump stage type is analyzed at multiple speeds and viscosities.

This viscous lab testing loop is capable of speeds up to 70 Hz, 30,000 B/D of fluid, with a maximum of 500 HP, and can manage fluid viscosities up to 2,500 cP. Four pumps were tested at speeds ranging from 40 to 70 Hz, in 10 Hz intervals, and up to 2,500 cP fluid viscosity. The viscosity correction factors, for each operating speed and viscosity, were developed for each pump stage and compared with the stage-specific speed.

The effects of viscosity and operating speed on flow, head, and horsepower were observed. An increase in viscosity deteriorates pump performance, while an increase in rotational speed reduces the rate of deterioration; therefore, increased operating speeds improve the performance of an ESP pump in viscous applications.

Additionally, diameter and specific speed effects (a "dimensionless[DL1] " number for pump design criteria) on viscosity are being investigated as a design criterion. A correlation is being developed for the effects of the specific speed on the viscosity correction factors. The new correlation will help obtain viscosity correction factors for other pumps with different diameters, operating at different speeds and viscosities, based on the specific speed relationship.

The service company's Research and Development department's viscosity testing program, its results, analysis, and new findings are discussed in this paper.
A Note on Negation of a Probability Distribution
Authors: Kaur Manpreet , SRIVAST AMIT
Published: August 2022

Evaluating the negation of an uncertain event is an open issue. Yager[14] suggested a transformation for evaluating the negation of a probability distribution. He used the idea that any event whose outcome is not certain can be negated by supporting the occurence of other events with no bias or prejudice for any particular outcome. Various authors have tried to generalize the negation transformation proposed by Yager[14] . However we need to focus on developing the basic structure of negation so that the behaviour of the process modelled by negation transformation can be understood in detail. Yager's negation is based on distribution of maximum entropy. If a probability distribution is uncertain(a state other than maximum entropy), the more iterations of negation, the more uncertain this probability event becomes eventually converging to a homogeneous state\textit{ i.e.} maximum entropy. In other words, it is the realization of the process. What is noted that during each negation, Yager's method ensures that the negation is intuitive, the next negation weakens the probability of the event occuring in the previous step. Since negation involves reallocation of probabilities at each step in such a way that the reallocation at each step can be determined from the reallocation at the previous step, therefore it is clear that Yager's negation has various attributes similar to that of a markov chain. In the present work, we have shown that Yager's definition of negation can be modelled as a markov chain which is irreducible, aperiodic with no absorbing states. Two examples has been discussed to strengthen and support the analytical results. Also we have defined an information generating function(IGF) whose derivative evaluated at specific points gives the moments of the self information of negation of a probability distribution. The properties of the generating function along with its relationship with the information generating function proposed by S. Golomb[2] has been explored. A closer look at the properties of IGF confirms the existence of markovian structure of Yager's Negation.Mathematics Subject Classification (2010) 90C70 · 90B06 · 90B50 · 90C05
Deformation mechanism and numerical analysis of seasonal landslide induced by permafrost degradation: a case study, Northeast China
Authors: Shan Wei , Ma Min , Guo Ying
Published: August 2022

There are few types of research on the occurrence mechanism and deformation characteristics of landslides induced by permafrost degradation. With the aggravation of climate warming, landslides are more and more common in permafrost regions. A slow landslide (the K178 + 530 landslide) in the permafrost region of the Xiao Xing'an Mountains in Northeast China was monitored for a long time. The deformation characteristics and occurrence mechanism of the landslide were studied using field investigation, on-site drilling, sensor monitoring, laboratory test, Google satellite image, unmanned aerial vehicle (UAV) photogrammetry, high-density electrical method, and ground-penetrating radar. In addition, a hydro-thermal-mechanical coupling model of frozen soil under saturated conditions was established to simulate the deformation process, pore water pressure change, and effective stress distribution of the slope, and the simulation results were verified according to the monitored data. The results show that the meltwater recharge caused by permafrost degradation reduced the cohesion and internal friction angle of the soil near the trailing edge of the landslide, thus providing dynamic and mechanical conditions for slope deformation. The melting of the continuous segregation ice in the active layer contributed to the formation of a sliding surface and provided deformation conditions for the start of the landslide. The combination of these two factors finally led to the occurrence of the landslide. According to its deformation mechanism, it can be judged that the landslide is a thrust-type landslide. In addition, the melting of ice lenses in the seasonally frozen layer is the main source of soil strength damage, and the landslide sliding rate reached the maximum when the ice lens melted completely. The K178 + 530 landslide is a typical case of landslides caused by permafrost degradation. This study provides a reference for the identification, early warning, and prevention measures of this type of landslide.
Mobility and HIV vulnerabilities among female sex workers in Guinea-Bissau: findings from an integrated bio-behavioral survey
Authors: Gorin Emma May , Lyons Carrie E , Jarrett Brooke A. , Djalo Mamadu Aliu , Barreto Kátia , Drame Fatou Maria , Baral Stefan
Published: August 2022

Background: Mobility is an important risk determinant for HIV given the potential for intermittent access to HIV services. Mobility may be particularly relevant among female sex workers, (FSW) who have been shown to be at high risk for HIV in settings around the world. Data regarding the role mobility plays in exacerbating HIV risks among FSW across Sub-Saharan Africa remains limited, and data on FSW in Guinea-Bissau is sparse.Methods: FSW in four regions of Guinea-Bissau were recruited with a respondent-driven sampling (RDS) method and participated in an integrated bio-behavioral survey. Associations between reported mobility and social and HIV vulnerabilities among FSW in Guinea-Bissau were assessed using multivariable logistic regression models. Results: 34.8% of respondents reported mobility to one location and 15.7% reported mobility to more than one location within the past six months. Statistical analysis demonstrated that mobility to more than one destination was significantly associated with recent sex without a condom with both clients (aOR: 2.57 (95% CI: 1.10, 6.00)) and non-paying partners (aOR: 4.73 (95% CI: 2.24, 10.02)) compared to non-mobility. However, mobility to one or more locations was also associated with higher odds of receiving HIV prevention information (mobility to one location: aOR: 1.63 (95% CI: 1.07, 2.49); mobility to >1 location: aOR: 2.34 (95% CI: 1.28,4.26)) and mobility to more than one location was associated with more engagement with HIV-related organizations (aOR: 2.26 (95% CI: 1.27, 4.04)).Conclusions: These results suggest that while some prevention services including HIV prevention information reach mobile FSW in Guinea-Bissau, HIV prevention needs remain unmet for mobile FSW in Guinea-Bissau.
Meat Quality of Sasso T44 and Koekoek cockerels exposed to temperature variation with supplementary Coriander seed powder
Authors: Gebreyohans Kiros Welay , Amaha Negassi , Demeke Solomon , Dubusho Legesse K. , Girma Mseret
Published: August 2022

This experiment was conducted to evaluate the effects of ambient temperature and coriander seed supplementations on meat quality of Sasso T44 and Koekoek. Both breeds were exposed to two temperatures rooms with a heated room of 32±1.2 0c from 11:00 am to 16:00 pm and the normal room temperature of average maximum and minimum of 23.8±30c and 16.6±1.60c, respectively, with a relative humidity between 34.5 ±4 to 44.8±3%. Both breeds were also further randomly allocated to three levels of 0g/kg, 5g/kg and 10g/kg coriander seed powder supplementations. The experiment was conducted from 10 to 20 weeks of age. There was a slight variation in meat color on lightness (L*; P<0.05) due to temperature at 48 hours after slaughtered. Breast meat from cockerels reared in a heated room became slightly lighter compared to groups reared at normal temperature (unheated room). However, the overall meat color did not categorized under the paled color of meat, rather it can be in the darker than normal category. Moreover, breast meat of Koekoek at 1hour after slaughtered was more yellow (P<0.05) in color and higher chroma values, while at 48 hours, Sasso T44 had redder meat (P<0.05) than Koekoek. In addition the thigh meat of Koekoek had more total ash than Sasso T44 (P<0.05). However, Sasso T44 breast meat had better water holding capacity due to lower in drip loss percentage (P<0.05) than Koekoek. This research indicated that some meat quality variations shown between breeds and due to temperature. However, further insights into other physical meat qualities and sensory evaluations may also reveal to the meat quality of these breeds.
Satellite assessment of eutrophication hot spots and algal blooms in small and medium-sized productive reservoirs in Uruguay's main drinking water basin
Authors: Zabaleta Bernardo Vicente , Aubriot Luis , Olano Hernán , Achkar Marcel
Published: August 2022

Intensive agricultural activities favor eutrophication and harmful phytoplankton blooms due to the high export of nutrients and damming of rivers. Productive watersheds used for water purification can have multiple reservoirs with phytoplankton blooms, which constitutes a high health risk. In general, water quality monitoring does not cover small and medium-sized reservoirs (0.25–100 ha) of productive use due to their large number and location in private properties. In this work, thein-situtrophic state of fourteen reservoirs was simultaneously assessed using Sentinel-2 images in the Santa Lucía River Basin, the main drinking water basin in Uruguay. These reservoirs are hypereutrophic (0.18–5.22 mg total P L-1) with high phytoplankton biomasses (2.8–4439 µg chlorophyll-a L-1), mainly cyanobacteria. Based on data generatedin-situand Sentinel-2 imagery, models were fitted to estimate satellite Chl-a and transparency in all the basin reservoirs (n = 486). The best fits were obtained with the green-to-red band ratio (560 and 665 nm, R2 = 0.84) to estimate chlorophyll-a and reflectance at 833 nm (R2 = 0.73) to determine transparency. The spatial distribution of the trophic state was explored by spatial autocorrelation and hotspot analysis, and the variation in spatial patterns could be determined prior and subsequent to a maximum cyanobacteria value in water treatment plant intakes. Therefore reservoirs with greater potential for phytoplankton biomass export were identified. This work provides the first fitted tool for satellite monitoring of numerous reservoirs, and strengthens the country's ability to respond to harmful phytoplankton blooms in its main drinking water basin.
Geomorphological analysis of landslide and early warning system for landslide risk mitigation in Nepalese mid-hills.
Authors: Thapa Prakash Singh , Adhikari Basanta Raj , Shaw Rajib , Bhattarai Diwakar , Yanai Seiji
Published: August 2022

The Nepalese Himalayas is one of the world’s most active mountain belts, with widespread natural hazards of various types, including landslides, which claim numerous lives and properties in Nepal. Landslides occur due to the combined effects of seismic activity, monsoon rainfall, and improper land-use practices. The prevention and mitigation of landslides are challenging for countries like Nepal, however, low-cost techniques such as bioengineering with low-cost early warning systems have been implemented in recent decades. The Methum landslide near Lalitpur was selected as a case study to investigate the landscape dynamics along with triggering factors, and to evaluate the effectiveness of a landslide early warning system (LEWS). The study assessed aerial photos, satellite images, and precipitation records and conducted multiple field visits to analyze patterns of landslide evolution, landslide risk, and potential triggers. Heavy rainfall, sloped terrace farming, and earthquakes are identified as major landslide triggers. LEWS, installed, measures rainfall, soil moisture, and displacement activity and generates an alarm if any of these parameters exceed the threshold set. This monitoring system is a cost-effective technique and exemplifies the reduction of landslide risk at the community level in the landslide-prone mid-hills of Nepal.
Study on the variation of MeHg content in different types of soils in non-ferrous metallurgical areas
Authors: Li Xinyu , Zheng Dongmei , Wang Yuqi , Xu Xiaoxiao
Published: August 2022

To study the methylation of mercury in soils of various utilization categories in typical non-ferrous metallurgical areas, soils of various utilization categories were selected for the experiment, and the changes of soil mercury, methylmercury, and SRB content were analyzed, whether the changes of SRB and the changes of soil physical and chemical properties affected the formation of methylmercury, and the results showed that: with the incubation time increased, the mercury content showed a decreasing-increasing-reducing trend. Except for the riverbank substrate, the MeHg content of the other five different land-use types exhibited a trend of rising and then falling, and the MeHg content of soils under flooded conditions was higher than that of non-flooded soils. SRB was present in all types of soils and promoted soil Hg methylation in the late incubation period. Among soil physical and chemical properties, pH and soluble sulfide were significantly correlated with MeHg content in some soils, indicating that MeHg formation was related to SRB, pH, and soluble sulfide, which is important for the study of different types of soils in non-ferrous metallurgical areas.