bluuebunny/crossref_metadata_2025 huggingface dataset:
The design of computer controlled ground information transmission down platform in drilling
Authors: Xing Dongqiu , Qi Lihua , Zhao Jing , Wang Yi
Published: March 2020

In order to improve the drilling efficiency and avoid the disadvantages of manual operation, the method of sending the surface intervention instruction with computer instruction is researched. Based on the similarity of liquid flow, a set of hydraulic circulation system is used to simulate the drilling process, selected the key components, designed and built the intelligent drilling system indoor experiment platform; Define different commands with the length of the time and decode them and carried out the sending command experiment. The results show that the platform can successfully send the command to the downhole under the condition of non-stop drilling, which is the attitude intervention, command coding and Weak signal detection in the intelligent drilling system provides a new platform.
Study on optimization of rake head density of suction hopper dredger based on bat algorithm and extreme learning machine
Authors: Hao Guangjie , Yu Menghong , Su Zhen
Published: March 2020

The dredging output of suction dredger mainly comes from the suction density of the rake head. Accurate prediction of suction density is of great significance to improve the dredging output of suction dredger. In order to overcome the shortcomings of low accuracy and poor real-time performance of the current inhalation density prediction methods, a bat algorithm is proposed to optimize the inhalation density prediction method of extreme learning machine. The bat algorithms for optimizing extreme learning machines prediction model is constructed based on the measured construction data of “Xinhaifeng” Yangtze Estuary, and compared with other prediction models. Finally, the bat algorithms for optimizing extreme learning machines model is used to build the output simulator of inhalation density. Compared with the actual construction, the selection of control parameters is analyzed when the output of inhalation density is the best. Experients show that bat algorithms for optimizing extreme learning machines prediction has high accuracy and good stability, and can provide scientific and effective reference for yield prediction and construction guidance.
HOPF bifurcation of the chemostat with delay and simplified holling type-iv response function
Authors: Li Yanqiu
Published: March 2020

In this paper, the author investigates Chemostat with Delay and Simplifified Holling Type-IV Response Function, which more match the actual meaning in the chemostat system. Using bifurcation theory, we discuss the hopf bifurcation stability in detail.
Fuzzy control and simulation of boiler drum water level
Authors: Meng Fansheng , Zhang Xuefei , Zheng Yan , Cheng Xi , Weng Zhi
Published: March 2020

Boiler drum water level control system is hard to develop practical mathematical model and has nonlinear, stable and delay characteristics. The traditional boiler drum water level control often uses three impulse PID control method. The existing problem of ordinary PID control strategy is: once good parameter setting, it is hard to adapt to the change of the operation of the system dynamic greatly. In order to solve the problems of the above, the research object of the subject is a certain 120 t/h boiler steam capacity, the boiler drum water level control system is designed, and the control strategies are studied. In order to obtain better contrast, the ordinary PID controller and Fuzzy controller are designed, and the control strategies of the simulation are analyzed.
Une société (de l’analyse) du risque ?
Authors: Demortain David
Published: March 2020

L’apparition des risques comme expérience collective et problèmes publics dans les sociétés contemporaines est inséparable de l’ambition de calculer et d’analyser ces risques. Ces deux phénomènes contemporains n’ont pourtant que rarement été rapportés l’un à l’autre. L’ouvrage inaugural de Beck sur la société du risque insiste sur la perte de crédibilité et d’autorité de la science dans l’énonciation de ce que seraient les risques, mais n’évoque pas l’émergence, pourtant contemporaine, d’une discipline dite de l’analyse des risques et la formalisation et l’universalisation de ses méthodes de calcul et d’aide à la décision. Allant au-delà de l’incohérence apparente de ces deux images de la société contemporaine − une société du risque et une société de l’analyse des risques –, l’article montre que la capacité à répondre aux controverses typiques de la première est précisément une des caractéristiques des savoirs de gouvernement typiques de la seconde.
Ultrasonography of the Peripheral Nerves of the Forearm, Wrist and Hand: Definition of Landmarks, Anatomical Correlation and Clinical Implications
Authors: Gruber Leonhard , Loizides Alexander , Peer Siegfried , Walchhofer Lisa Maria , Spiss Verena , Brenner Erich , Stahl Kathrin , Gruber Hannes
Published: March 2020

Background Peripheral nerve pathologies of the upper extremity are increasingly assessed by high-resolution ultrasonography (HRUS), yet rapid identification of nerve segments can be difficult due to small nerve diameters and complex regional anatomy. We propose a landmark-based approach to speed up and facilitate evaluation and intervention in this region.

Method Relevant landmarks and section planes for eleven nerve segments of the forearm, wrist and hand were defined by ultrasonography in cadaver arms before cryosection and topographical neurovascular preparation. Information on all nerve segments and a pictorial guide including anatomical cross-sections, topographical preparations and HRUS images are provided. The identification rates of these nerve segments were then assessed in 20 healthy volunteers.

Results and Conclusion Sonographic landmarks and guidelines for the rapid identification and assessment of nerves of the forearm, wrist and hand are presented in pictorial and tabular form, including discussion of normal variants. Utilizing this overview should facilitate training, diagnostic examinations and intervention for nerves of the upper extremity.

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Citation Format
Entwicklung eines Systems zur Risikoanalyse bei der Behandlung mit offenen radioaktiven Stoffen in der Nuklearmedizin
Authors: Kotzerke Jörg , Fetzer Patrick , Grosche-Schlee Sabine , Hanel Andreas , Freudenberg Robert , Brogsitter Claudia
Published: March 2020

Ziel Die neue Strahlenschutz-Gesetzgebung sieht vor, dass eine Risikoanalyse neuer und bestehender Behandlungsverfahren mit offenen Radionukliden hinsichtlich der Patientensicherheit wiederkehrend durchzuführen ist, in welche der Medizinphysik-Experte maßgeblich involviert ist.

Material und Methoden Als Werkzeug für die Durchführung der Risikoanalyse wurde die Fehlermöglichkeits- und Einflussanalyse (FMEA) angewendet, wie vom Bundesamt für Strahlenschutz (BfS) und den Fachgesellschaften empfohlen. Für die Radiojodtherapie, die Radiosynoviorthese, die Peptid-Radiorezeptortherapie und die selektive interne Radiotherapie wurden die Prozesse gegliedert und zunächst individuell durch die verschiedenen am Prozess beteiligten Berufsgruppen und anschließend im Konsens kategorisiert. Für Risikoprioritätszahlen > 125 wurden Gegenmaßnahmen erarbeitet. Die Risikoprioritätszahl (RPZ) ergibt sich als Produkt aus dem Schweregrad, der Auftretenswahrscheinlichkeit und der Entdeckungswahrscheinlichkeit des Fehlers oder der Folgen.

Ergebnisse Neben den diversen Möglichkeiten der Verwechslung von Patienten wurden Unsicherheiten in der Aktivitäts- und Organgrößenbestimmung und eine mangelnde Compliance des Patienten als wesentliche Risiken für eine Unter- oder Übertherapie angesehen. Die ausgeprägte Streuung bei individueller Risikobetrachtung durch einzelne Berufsgruppen konnte unter Anleitung durch einen externen Moderator deutlich reduziert werden. Für die höchsten RPZ wurden Maßnahmen formuliert, deren präventive Wirkung im Verlauf noch zu überprüfen ist.

Schlussfolgerung Die nuklearmedizinische Therapie wurde in der organisatorischen Durchführung als sehr sicher eingeschätzt und es wurden nur geringe Risiken bzgl. der Patientensicherheit identifiziert. Die FMEA-Analyse war ein praktikables Instrument und identifizierte Prozessschritte mit Optimierungspotenzial für die analysierten Therapieformen. Das geschilderte Vorgehen kann in anderen nuklearmedizinischen Einrichtungen adaptiert werden, wobei strukturspezifische Faktoren (technische und personelle Ausstattung, Ablauf von Prozeduren) zu berücksichtigen sind, sodass ggf. weitere Risiken identifiziert und hier aufgeführte Risiken aufgrund anderer Abläufe als abweichend eingeschätzt werden können.
Die Einführung eines permanenten Erhebungssystems zur Messung der Lebensqualität von HNO-Patienten an der Klinik für Strahlentherapie am Universitätsklinikum Freiburg: Implementierungsbericht
Authors: Sprave Tanja , Nicolay Nils Henrik , Grosu Anca-Ligia , Lindenmeier Jörg , Tscheulin Dieter K.
Published: March 2020

Hintergrund Die Anwendung des standardisierten, allgemein anerkannten EQ-5D-5L Erhebungsinstrumentes in der klinischen Routine ermöglicht eine Erfassung der jeweiligen subjektiven Gesundheitszustände und dadurch die Ermittlung von international vergleichbaren Behandlungseffekten. Des Weiteren kann es im Rahmen des internen Qualitätsmanagements zur Überwachung der Leistung des Instituts als Messinstrument eingesetzt werden. Die Implementierung des permanenten Erhebungssystems mittels validierten EQ-5D-5L Fragebogens zur Messung der Lebensqualität von HNO-Patienten wurde dokumentiert.

Methoden Die subjektive Lebensqualität (QOL) von ambulanten und stationären Patienten wird jeweils vor Behandlungsbeginn, zum Abschluss und zu den jeweiligen Nachsorgeterminen durch Fragebögen manuell erfasst. Die Ergebnisse werden digitalisiert und in einer zentralen Datenbank gespeichert. Die Fragebögen werden eingescannt und finden Eingang in die digitalen Patientenakten.

Ergebnisse Die Therapieüberwachung von HNO-Krebspatienten zur internen Qualitätssicherung mittels des EQ-5D-5L Fragebogens in Papierform wurde im Juli 2019 im Rahmen eines Pilotprojektes gestartet. Die Projektverantwortlichen wurden benannt und Projektziele definiert. Initial erhielt das Personal allgemeine und individuelle Schulungen sowie regelmäßige Erinnerungen. Die prozedurale Implementierungsphase betrug ca. 10 Wochen. Innerhalb von 3 Monaten wurden ca. 200 Bögen eingeholt. Es zeigte sich eine hohe Patienten-Compliance (98 %).

Schlussfolgerungen Eine permanente Verwendung des EQ-5D-5L Fragebogens bei HNO-Krebspatienten zur Qualitätssicherung ist durchführbar. Die Implementierung in die klinische Versorgungsroutine ist nach der entsprechenden Personalschulung realisierbar.
Contemporary Management of Hepatic Trauma: What IRs Need to Know
Authors: Gilyard Shenise , Shinn Kaitlin , Nezami Nariman , Findeiss Laura K. , Dariushnia Sean , Grant April A. , Hawkins C. Matthew , Peters Gail L. , Majdalany Bill S. , Newsome Janice , Bercu Zachary L. , Kokabi Nima
Published: March 2020

Trauma remains one of the leading causes of death in the United States in patients younger than 45 years. Blunt trauma is most commonly a result of high-speed motor vehicular collisions or high-level fall. The liver and spleen are the most commonly injured organs, with the liver being the most commonly injured organ in adults and the spleen being the most affected in pediatric blunt trauma. Liver injuries incur a high level of morbidity and mortality mostly secondary to hemorrhage. Over the past 20 years, angiographic intervention has become a mainstay of treatment of hepatic trauma. As there is an increasing need for the interventional radiologists to embolize active hemorrhage in the setting of blunt and penetrating hepatic trauma, this article aims to review the current level of evidence and contemporary management of hepatic trauma from the perspective of interventional radiologists. Embolization techniques and associated outcome and complications are also reviewed.
Penetrating Extremity Trauma Endovascular versus Open Repair?
Authors: Kuwahara Jeffery T. , Kord Ali , Ray Charles E.
Published: March 2020

Penetrating extremity trauma (PET) accounts for an estimated 5–15% of trauma with vascular injury and these injuries are accountable for a significant percentage of trauma-related deaths. Historically, vascular injuries were best treated by open repair. While a defined selection criteria and a comprehensive algorithm have not been validated, the advancement of endovascular techniques, embolotherapy, and stent grafting have become viable options for the treatment of penetrating arterial extremity trauma in select patients. Advantages endovascular repair offers include decreasing mortality and morbidity associated with open repair, decreasing blood loss, decreasing iatrogenic injury such as nerve injury, and lower rate of wound infection. Patients stability, type of vascular injury, and lesion location are main factors help deciding between endovascular and open repair. Patient selection between endovascular and open repair should be determined by on a case-by-case situation, individual hospital guidelines, a multidisciplinary approach, and technical expertise.
Emergent Treatment of Acute Cholangitis and Acute Cholecystitis
Authors: Navuluri Rakesh , Hoyer Matthew , Osman Murat , Fergus Jonathan
Published: March 2020

Acute pathology of the biliary tract including cholangitis and cholecystitis can lead to biliary sepsis if early decompression is not performed. This article provides an overview of the presenting signs and symptoms and role of interventional radiology in the management of patients with acute cholangitis or acute cholecystitis. It is especially important to understand the role of IR in the context of other treatment options including medical management, endoscopy, and surgery.
Prognostic Factors and Nomogram Predicting Survival in Diffuse Astrocytoma
Authors: Tunthanathip Thara , Ratanalert Sanguansin , Sae-heng Sakchai , Oearsakul Thakul , Sakaruncchai Ittichai , Kaewborisutsakul Anukoon , Chotsampancharoen Thirachit , Intusoma Utcharee , Kitkhuandee Amnat , Vaniyapong Tanat
Published: March 2020

Background Prognosis of low-grade glioma are currently determined by genetic markers that are limited in some countries. This study aimed to use clinical parameters to develop a nomogram to predict survival of patients with diffuse astrocytoma (DA) which is the most common type of low-grade glioma.

Materials and Methods Retrospective data of adult patients with DA from three university hospitals in Thailand were analyzed. Collected data included clinical characteristics, neuroimaging findings, treatment, and outcomes. Cox’s regression analyses were performed to determine associated factors. Significant associated factors from the Cox regression model were subsequently used to develop a nomogram for survival prediction. Performance of the nomogram was then tested for its accuracy.

Results There were 64 patients with DA with a median age of 39.5 (interquartile range [IQR] = 20.2) years. Mean follow-up time of patients was 42 months (standard deviation [SD] = 34.3). After adjusted for three significant factors associated with survival were age ≥60 years (hazard ratio [HR] = 5.8; 95% confidence interval [CI]: 2.09–15.91), motor response score of Glasgow coma scale < 6 (HR = 75.5; 95% CI: 4.15–1,369.4), and biopsy (HR = 0.45; 95% CI: 0.21–0.92). To predict 1-year mortality, sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the curve our nomogram was 1.0, 0.50, 0.45, 1.0, 0.64, and 0.75, respectively.

Conclusions This study provided a nomogram predicting prognosis of DA. The nomogram showed an acceptable performance for predicting 1-year mortality.
Recommendations of the Colombian Consensus Committee for the Management of Traumatic Brain Injury in Prehospital, Emergency Department, Surgery, and Intensive Care (Beyond One Option for Treatment of Traumatic Brain Injury: A Stratified Protocol [BOOTStraP])
Authors: Rubiano Andres M. , Vera David S. , Montenegro Jorge H. , Carney Nancy , Clavijo Angelica , Carreño Jose N. , Gutierrez Oscar , Mejia Jorge , Ciro Juan D. , Barrios Ninel D. , Soto Alvaro R. , Tejada Paola A. , Zerpa Maria C. , Gomez Alejandro , Navarrete Norberto , Echeverry Oscar , Umaña Mauricio , Restrepo Claudia M. , Castillo Jose L. , Sanabria Oscar A. , Bravo Maria P. , Gomez Claudia M. , Godoy Daniel A. , Orjuela German D. , Arias Augusto A. , Echeverri Raul A. , Paranos Jorge
Published: March 2020

Background Traumatic brain injury (TBI) is a global public health problem. In Colombia, it is estimated that 70% of deaths from violence and 90% of deaths from road traffic accidents are TBI related. In the year 2014, the Ministry of Health of Colombia funded the development of a clinical practice guideline (CPG) for the diagnosis and treatment of adult patients with severe TBI. A critical barrier to the widespread implementation was identified—that is, the lack of a specific protocol that spans various levels of resources and complexity across the four treatment phases. The objective of this article is to present the process and recommendations for the management of patients with TBI in various resource environments, across the treatment phases of prehospital care, emergency department (ED), surgery, and intensive care unit.

Methods Using the Delphi methodology, a consensus of 20 experts in emergency medicine, neurosurgery, prehospital care, and intensive care nationwide developed recommendations based on 13 questions for the management of patients with TBI in Colombia.

Discussion It is estimated that 80% of the global population live in developing economies where access to resources required for optimum treatment is limited. There is limitation for applications of CPGs recommendations in areas where there is low availability or absence of resources for integral care. Development of mixed methods consensus, including evidence review and expertise points of good clinical practices can fill gaps in application of CPGs. BOOTStraP (Beyond One Option for Treatment of Traumatic Brain Injury: A Stratified Protocol) is intended to be a practical handbook for care providers to use to treat TBI patients with whatever resources are available.

Results Stratification of recommendations for interventions according to the availability of the resources on different stages of integral care is a proposed method for filling gaps in actual evidence, to organize a better strategy for interventions in different real-life scenarios. We develop 10 algorithms of management for building TBI protocols based on expert consensus to articulate treatment options in prehospital care, EDs, neurological surgery, and intensive care, independent of the level of availability of resources for care.
A modified measurement method of electrical properties for ZnO microvaristors by direct measurements
Authors: Abe Takuya , Kabir Mahmudul , Sakurada Kouki , Minowa Masahiro
Published: March 2020

Zinc oxide (ZnO) materials are fine ceramics with non-linear electrical properties. Their non-linear electrical properties appear from a double Schottky barrier formed in the grain boundaries (GBs). These microparticles are not easy to measure directly with electrical microprobes due to their small size (i.e., 50–100 µm). We developed a direct measurement process with two Cu cables of small diameter. In this paper, we have developed an amplified method of the previous measurement system, which can measure not only one ZnO microvaristor directly but also a group of microvaristors in a series connection. The I–V characteristics of the microvaristors were measured with the modified method, and we found non-linear properties in each particle while measuring I–V characteristics. Their fine structures were also investigated, and the non-linear I–V characteristics showed a direct relationship with the number of the GBs of the samples. Moreover, varistor voltage was calculated for a single GB for the I–V measurements for ZnO microvaristors connected in a series connection.
Energy-environmental efficiency of clean energy in China: Integrated analysis with regional green growth
Authors: Xu Lei , Miao Shanshan , Deng Yanfei , Mancl Karen
Published: March 2020

Green growth has become an increasingly important paradigm for sustainable economic growth, resource development, and environmental protection. As the main focus in energy led green growth is a move away from fossil energy to clean energy, sustainable green growth resource development needs to measure both energy and environmental efficiencies. As the largest global energy consumer and carbon emitter, China has had to deal with serious energy and environmental issues in recent years, with its regional green growth performances being poorly assessed. Therefore, green growth clean energy-environmental efficiency assessments were examined in this paper, for which an integrated principal component analysis-data envelopment analysis based analysis approach was developed. It was found that while China's green growth has had a significant increasing trend in recent years, overall it was still at a low level, with the imbalances in China's regional economic development being reflected in its green growth. However, the excellent development and utilization of clean energy in most regions have significantly promoted a continuous improvement in China's green growth and the move toward sustainable resource development and utilization is contributing to long-term green growth. Green growth has also placed new demands on sustainable resource development in China. Therefore, underdeveloped regions that have sustainable resource endowments need to develop industrial systems that have clean energy as the main axis, and developed regions need to develop high-end industries that have low energy consumption and encourage mutual support systems between regions to ensure optimal sustainable resource, green growth development patterns.
Dietary supplementation with L-arginine and combinations of different oil sources beneficially regulates body fat deposition, lipogenic gene expression, growth performance and carcass yield in broiler chickens
Authors: Khatun J. , Loh T. C. , Akit H. , Foo H. L. , Mohamad R. , Kareem K. Y.
Published: March 2020

Context Broiler meat with excessive of fat and saturated fatty acids content has serious health implication for consumers. The accumulation of abdominal fats in broiler chickens constitutes a loss of dietary energy and also reduces carcass yield. Oil rich in unsaturated fatty acids and l-arginine are effective for reducing fat deposition and improve meat quality. Aims The aim of this study was to examine the effects of supplementation of l-arginine (l-Arg) with four combinations of palm oil (PO) and sunflower oil (SO) on growth performance, carcass yield, fat deposition, lipogenic gene expression and blood lipid profile in broiler chickens. Methods A total of 180 1-day-old chicks (Cobb 500) were randomly assigned to five dietary treatments as: T1, 6% PO (control); T2, 6% PO + 0.25% l-Arg; T3, 4% PO + 2% SO + 0.25% l-Arg; T4, 2% PO + 4% SO + 0.25% l-Arg; and T5, 6% SO + 0.25% l-Arg. Key results Birds fed l-Arg and combinations of PO and SO had higher weight gain at starter and finisher period compared with the control. The carcass yield increased, and relative abdominal fat reduced in broiler fed with combinations of l-Arg and increased level of SO in the diet. The concentration of oleic, palmitoleic and total monounsaturated fatty acids in liver tissue decreased by addition of l-Arg in broiler diet. The palmitic and total saturated fatty acid decreased, and total unsaturated fatty acid and polyunsaturated fatty acids increased in liver tissue when PO replaced progressively by SO supplemented with l-Arg in the diet. The acetyl-CoA carboxylase , stearoyl-CoA desaturase and fatty acid synthetase gene expression tended to decrease by supplementation of l-Arg with an increased level of SO compared with control. Conclusion Supplementation with l-Arg and combination of PO and SO at the ratio of 4:2 could inhibit lipogenesis and subsequent lower abdominal fat deposition and enhance growth performance and carcass yield in broiler chickens. Implications Ratio of PO and SO, 4:2 with l-Arg supplementation in the dietary of broiler chickens can contribute to a better growth performance, lesser fat deposition and greater carcass yield.
Genetic variation for leaf carbon isotope discrimination and its association with transpiration efficiency in canola (Brassica napus)
Authors: Hossain Shek M. , Masle Josette , Easton Andrew , Hunter Malcolm N. , Godwin Ian D. , Farquhar Graham D. , Lambrides Christopher J.
Published: March 2020

Drought is a major constraint to canola production around the world. There is potential for improving crop performance in dry environments by selecting for transpiration efficiency (TE). In this work we investigated TE by studying its genetic association with carbon isotope discrimination (Δ) and other traits, e.g. specific leaf weight (SLW) and leaf chlorophyll content (SPAD). Among the 106 canola genotypes – including open-pollinated, hybrid, inbred types and cytoplasmic variants – tested in the field and glasshouse there was significant genotypic variation for TE, Δ, plant total dry weight, SLW and SPAD. Strong negative correlations were observed between TE and Δ (–0.52 to –0.76). Negative correlations between Δ and SLW or SPAD (–0.43 to –0.78) and smaller but significant positive correlations between TE and SLW or SPAD (0.23 to 0.30) suggested that photosynthetic capacity was, in part, underpinning the variation in TE. A cytoplasmic contribution to genetic variation in TE or Δ in canola was also observed with Triazine tolerant types having low TE and high Δ. This study showed that Δ has great potential for selecting canola germplasm with improved TE.
Scientific research and languages in Portuguese Higher Education Institutions
Authors: Pinto Susana , Araújo e Sá Maria Helena
Published: March 2020

This paper reports on a study that looked at Portuguese public universities setting out to identify and discuss
institutional stakeholders’ social representations concerning the use of languages in scientific research and the development of
institutional language policies within this area of higher education activity. In order to do so, institutional stakeholders
responsible for research activities at six Portuguese public universities completed a questionnaire and participated in in-depth
interviews. The findings indicate there are common tendencies regarding the identified social representations that point, mainly,
to a tension between, on one hand, the existence of reported practices that centre on “English-mainly” research language policies,
reflecting the current monolingual scenario of global science and, on the other hand, the need for a more plurilingual science and
the privileging of Portuguese as a science language.
Language competition modeling and language policy evaluation
Authors: Templin Torsten
Published: March 2020

In this paper, we present a framework for the analysis of effects of language policies on the competition between
languages. At the core of this framework is a language competition model that takes into account four pivotal factors for the
evolution of the linguistic composition of a society: intergenerational language transmission, formal language education, adult
language learning and migration. In contrast to the majority of models available in the literature, our model operates with
parameters that can be estimated from empirical socio-linguistic data. It allows the reconstruction of past and simulate future
dynamics. Language policies can be modeled as changes in model parameters. Therefore, projections derived from the model can be
utilized to compare the effects of different policy options. We use Basque and Spanish within the Basque Autonomous Community in
Spain to illustrate the application of the model.
Azerbaijan and the Transcaucasian Democratic Federative Republic: historical reality and possibility
Authors: Mamoulia Georges
Published: March 2020

This article examines the origins, negotiations and considerations surrounding the formation and then rapid dissolution of the independent Transcaucasian Democratic Federative Republic (TDFR) in 1918 from the perspective of Azerbaijani statesmen. Left with few alternatives in the rapidly changing geopolitical situation to accomplish their goals and assure their interests – primarily the economic and physical security of the Azerbaijani Muslim population, and also the recovery of Baku from Bolshevik control – other than to seek the backing of Ottoman Turkey, the Azerbaijani faction in the Transcaucasian Seim nevertheless advocated for the principle of federation, stood up against Turkish intentions regarding the status of Batumi, and did not support the incorporation of their country into the Ottoman Empire. In order to properly evaluate the role of the Azerbaijanis in the creation of the ephemeral TDFR, it is essential to examine the fundamentals of the history of Transcaucasia from the Bolshevik October coup in 1917 until the creation of the TDFR on 22 April 1918 and its dissolution into independent states on 26–28 May 1918.
Wind turbine power curve upgrades: methods for the assessment and test cases study
Authors: Castellani Francesco , Astolfi Davide , Terzi Ludovico
Published: March 2020

The research about wind turbine control and blade design optimization has flourished in the latest years and has provided the opportunity of diffusely updating the technology of operating wind turbines. Due to multivariate dependence of wind turbine power on ambient conditions and working parameters, it is complex to estimate the actual impact of power optimization strategies. This problem therefore calls for devoted operation data mining and statistical techniques, which are explored in the present work. In particular, two test cases of multi-MW wind turbines power upgrades are discussed: the former is a combined aerodynamic and control optimization, the latter is the optimization of the yaw control. The assessment of the upgrades impact is performed through the comparison between the post-upgrade measured production and a model estimate of the pre-upgrade production in the same conditions. The wind turbines nearby to the target upgraded ones are employed as references for the operation conditions and their working parameters are employed for a principal component regression of the power of the target wind turbine. The proposed method is general and, for the selected test cases, it arises that the aerodynamic and control optimization improves the Annual Energy Production of the order of the 3%, while the yaw control optimization provides a 1% AEP improvement.
Turbine Wake Deflection Measurement in a Wind Tunnel with a Lidar WindScanner
Authors: Hulsman Paul , Wosnik Martin , Petrović Vlaho , Hölling Michael , Kühn Martin
Published: March 2020

Wind turbines are typically closely spaced in wind farms, and thus operate in the wake of upstream turbines and experience power losses. Currently, one of the techniques to reduce the wake interaction between turbines within a wind farm is to yaw the upstream turbine with regards to the incident wind direction. The objective is to deflect the wake, which can potentially increase the overall power output and the annual energy production of the wind farm. Experimental data can aid the process to thoroughly analyse the wake deflection under different inflow conditions, which is necessary to apply a yaw-based wind farm control model. The aim of the present research is to investigate the possibility and accuracy of the experimental setup to measure the wake characteristics with a high spatial and temporal resolution through the use of a short-range Lidar WindScanner, within the wind tunnel of ForWind-Oldenburg. This technique provides the opportunity to analyse the flow structures at different operational and inflow conditions in a relative fast manner without disturbing the flow. Experiments were conducted using a model wind turbine in a large cross-section wind tunnel. The short-range Lidar WindScanner is used as the primary instrument to map the wind turbine wake at different downstream locations. The flow structures of the wake were measured from 1 D up to 10 D downstream of the turbine rotor. A stable flow within the wind tunnel segment is measured, which is crucial for the analyses of the evolution of the wake. In addition, a high detailed spatial resolution of the wake profile is observed, showing the symmetric and asymmetric behaviour of the wake, for unyawed and yawed conditions, respectively. Furthermore, the calculation of the thrust coefficient from the velocity data show expected behaviour, giving further credibility to the measurement technique.
Wind turbine control: open-source software for control education, standardization and compilation
Authors: Mulders S P , Zaaijer M B , Bos R , van Wingerden J W
Published: March 2020

Standardized, easy to use, and preferably open-source research software is an important aspect in supporting and solidifying the wind turbine community. To this end, three contributions in the form of open-source software projects are presented in this paper. First, a community-driven wind turbine baseline controller, the Delft Research Controller (DRC), is presented. The DRC is applicable to high-fidelity simulation software that uses the DISCON controller interface. The controller distinguishes itself by the variety of available control and estimation implementations, its ease of use, and the universal applicability to wind turbine models. Secondly, in the wake of the DRC, the SimulinkDRC graphical controller design and compilation environment has been developed. Users having access to Simulink can benefit from the convenient way of controller development the tool provides. Finally, the FASTTool has been developed for educational purposes, by focusing on the graphical aspect of wind turbine (controller) design. The tool simplifies interaction with the advanced FAST simulation software, by comprehensive visualizations and analysis tools. This paper demonstrates and describes the functionality of all three software projects.
Optimizing the Use of LIDAR in Wind Farms: Minimizing Life-Cycle Cost Impact of Yaw Error
Authors: Bakhshi Roozbeh , Sandborn Peter
Published: March 2020

Yaw error lowers the efficiency and reliability of wind turbines resulting in higher maintenance costs. LIDAR devices can correct the yaw error; however, they are expensive, which creates a trade-off between their costs and benefits. In this study, a stochastic discrete-event simulation model is developed that models the operation of a wind farm. We optimize the net present value (NPV) changes associated with using LIDAR devices in a wind farm to determine the optimum number of LIDAR devices and their associated turbine stay time as a function of number of turbines in the wind farm for specific turbine sizes.
Aerodynamic performance prediction of SG6043 airfoil for a horizontal-axis small wind turbine
Authors: Shin Pyungho , Kim Keonhoon
Published: March 2020

In order to design a small wind turbine, the performance of SG604x airfoil and previously existing 15 airfoils was reviewed at a Reynolds number of 300,000, which suggests the maximum lift-to-drag ratio of the airfoils, corresponding lift coefficient, and the maximum lift coefficient for both free and fixed transition. The SG6043 airfoil provides enhanced lift-to-drag ratio performance as compared with previously existing airfoils at a Reynolds number of 300,000. Only a SG6043 airfoil for small wind turbine performance prediction is applied along the length of the blades. This is why a blade constructed using airfoils of different performance may not exhibit the expected performance. A code based on BEMT(Blade Element/Momentum Theory) was used for performance predictions of small horizontal axis wind turbine. As important input parameter of BEMT, distributions of chord and twist was derived by the optimization method using genetic algorithm. The power performance prediction of airfoil data of SG6043 using BEMT is presented over a wide range of wind speeds. The results of BEMT using SG6043 show that the rated wind speed can be reduced to 10 m/s for a rotor radius of 7.25m and a rating of 32kW. The reduced rated wind speed would increases the annual capacity factor as compared the existing airfoils.
A graduate level course on economic metrics and innovative finance mechanisms for wind
Authors: Miller L , Carriveau R
Published: March 2020

A graduate level course on economic metrics and innovative finance mechanisms for has been developed. Topics include non-traditional financing structures for project development and the application of economic metrics to investment decision making. The development of this course was motivated by recent surveys and through consultation with wind energy professionals. Recent surveys have indicated that highly qualified persons entering renewable energy fields are lacking knowledge of the technical, economic, and policy-connected aspects of their work. Synthesis of these discussions, which have guided the development of course content, highlighted that an understanding of market policy and project economics would greatly enhance the efficacy of energy technical professionals. The purpose of this course is to develop holistically equipped wind energy professionals who can intelligently engage with business and finance professionals in their field. Both live instruction and online versions of this course intend to provide this knowledge through application-based lectures and case studies to set graduates of this course apart from their peers. Course delivery, topics, learning outcomes, and evaluation methods are provided.
Surface roughness for offshore wind energy
Authors: Golbazi Maryam , Archer Cristina L.
Published: March 2020

The Northeastern coast of the U.S. is expected to increase its offshore wind capacity from 30 MW today to 86 GW by 2050. Measurements of wind speeds are available near sea level, but not at hub height, thus extrapolation is often required using the surface roughness,z0. The focus of this study is to estimate the surface roughness length off the Northeastern coast of the U.S. using field measurements from Nantucket Sound, MA, with three methods: 1) analytical, dependent on friction velocity and atmospheric stability, 2) the Charnock relationship between zo and friction velocity, and 3) a statistical method, based on wind speed observations at three heights. The main results of this paper are: a comparison of the three methods, a comprehensive error analysis of each method, a regionalz0value of 10–3m, and a new mathematical interpretation of surface roughness.
Large eddy simulations of offshore wind turbine wakes for two floating platform types
Authors: Johlas H M , Martínez-Tossas L A , Lackner M A , Schmidt D P , Churchfield M J
Published: March 2020

The growing prospect for large farms of floating offshore wind turbines requires a better understanding of wake effects for floating turbines. In this work, large eddy simulations with an actuator line model are used to study the wake of the NREL 5 MW reference turbine mounted on the OC3-UMaine spar and OC4-DeepCwind semi-submersible platforms. The simulations are carried out in the Simulator fOr Wind Farm Applications (SOWFA) coupled with OpenFAST for the platform and turbine motion. The wake location, deficit, and turbulence levels are compared for the two floating platforms and equivalent fixed-turbine cases. The effects of neutral versus stable atmospheric conditions are also compared. Most notably, floating-turbine wakes are deflected upwards compared to fixed-turbine wakes, because of mean platform pitch. The spar wake deflects upwards more than the semi-submersible, while the stable atmosphere increases this vertical deflection compared to the neutral. The time-varying rotor motions do not significantly affect the mid-to-far wake, though the stable atmosphere shows larger fixed-floating differences in horizontal wake fluctuations.
Comparison of dynamic response and levelized cost of energy on three platform concepts of floating offshore wind turbine systems
Authors: Kikuchi Yuka , Ishihara Takeshi
Published: March 2020

Spar, semisubmersible and barge platforms are modelled based on the full-scale demonstration projects in Japan for a generic 5 MW turbine. Three platforms are evaluated with the structural and stability parameters. The characteristic of floater motions and mooring forces are clarified by performing the dynamic analysis. The dynamic responses are validated with the water tank tests. The levelized cost of energy is assessed by using the engineering cost model.
Influence of the Mass and Line Stiffiness on the Dynamic Line Tension of a Floating Offshore Wind Turbine Stabilized by a Suspended Counterweight
Authors: Ward J C , Goupee A J , Viselli A M , Dagher H J
Published: March 2020

As the offshore wind industry moves towards deeper waters, developers are adapting classical floating platform designs to optimize performance and cost. One such concept is a multi-body system consisting of a counterweight suspended from a buoyant hull using flexible cables. If the suspension lines remain in tension, the system may be assumed to behave as a rigid body. However, if a suspension line loses tension, relative motion between the bodies will occur which may destabilize the system. In this work, the hanging-mass floating offshore wind turbine is idealized as a forced spring pendulum. A parametric study is conducted by varying the line stiffness and counterweight mass to determine their effect on the dynamic line tension and global response of the system.
A computational model of wind turbine blade erosion induced by raindrop impact
Authors: Hu W , Wang X , Chen W , Wang Y , Liu Z , Tan J , Pryor S C , Barthelmie R J
Published: March 2020

This research focuses on developing a computational model for analysing wind turbine blade erosion induced by raindrop impact. A stochastic rain texture model is used to simulated realistic rain events determined by a rain intensity and a rain duration. A new smoothed particle hydrodynamic approach is implemented to study the influence of the raindrop size, impact speed, impact angle, and raindrop shape on the impact stress. In addition, a stress interpolation method is proposed to accurately and efficiently calculate the impact stress under a random rain event. The fatigue damage of the top coating material is evaluated under a rain event based on the rainflow cycle counting method and the Miner’s rule.
Wind Farm Simulation and Layout Optimization in Complex Terrain
Authors: Allen Jeffery , King Ryan , Barter Garrett
Published: March 2020

This work reports on incorporating complex terrain into wind farm simulations for the purpose of layout optimization. Adding complex terrain boundary conditions to NREL’s medium fidelity Reynolds averaged Navier-Stokes flow model, WindSE, produces significant separation, flow curvature, and speedup effects that would otherwise be difficult to capture with lower-fidelity models or a flat-terrain assumption. These flow features, in turn, can significantly impact the optimal turbine array layout. We demonstrate the addition of complex terrain improves agreement with SCADA data by 34.8% in mean average error. Additionally, we discuss modifications to the code that enable gradient-based layout optimization using terrainaware adjoints with arbitrary topography. Through several optimization case studies, we show that the layout optimization process takes advantage of speedup effects on terrain high points, and leverages flow curvature effects that modify wake trajectories. This yields substantial power improvements over gridded layouts, and hints at future research directions in simulation and optimization for wake trajectories in complex terrain.
Investigation of the near-wake behaviour of a utility-scale wind turbine
Authors: Abraham Aliza , Dasari Teja , Hong Jiarong
Published: March 2020

Super-large-scale particle image velocimetry and flow visualization with natural snowfall is used to collect and analyse multiple datasets in the near wake of a 2.5 MW wind turbine. Each dataset captures the full vertical span of the wake from a different perspective. Together, these datasets compose a three-dimensional picture of the near-wake flow, including the effect of the tower and nacelle and the variation of instantaneous wake expansion in response to changes in turbine operation. A region of high-speed flow is observed directly behind the nacelle, and a region of low-speed flow appears behind the tower. Additionally, the nacelle produces a region of enhanced turbulence in its wake while the tower reduces turbulence near the ground as it breaks up turbulent structures in the boundary layer. Analysis of the instantaneous wake behavior reveals variations in wake expansion – and even periods of wake contraction – occurring in response to changes in angle of attack and blade pitch gradient. This behaviour is found to depend on the region of operation of the turbine. These findings can be incorporated into wake models and advanced control algorithms for wind farm optimization and can be used to validate wind turbine wake simulations.
Comparison of Rotor Wake Identification and Characterization Methods for the Analysis of Wake Dynamics and Evolution
Authors: Quon E. W. , Doubrawa P. , Debnath M.
Published: March 2020

Optimal wind power plant design requires understanding of wind turbine wake physics and validation of engineering wake models under wake-controlled operating conditions. In this work, we have developed and investigated several different wake identification and characterization methods for analyzing wake evolution and dynamics. The accuracy and robustness of these methods, based on Gaussian function fitting and adaptive contour identification, have been assessed by application to a large-eddy simulation data set. A new contour-based method based on downstream momentum deficit has been considered. Uncertainties arising from wake-identification errors result in characterizations of the wake expansion, recovery, and meandering motion that differ by 19% of the rotor area, 4% of the freestream, and 15% rotor diameter, respectively.
ExaWind: A multifidelity modeling and simulation environment for wind energy
Authors: Sprague M A , Ananthan S , Vijayakumar G , Robinson M
Published: March 2020

We introduce the open-source ExaWind modeling and simulation environment for wind energy. The primary physics codes of ExaWind are Nalu-Wind and OpenFAST. Nalu-Wind is a wind-focused computational fluid dynamics (CFD) code that is coupled to the whole-turbine simulation code OpenFAST. The ExaWind environment was created under U.S. Department of Energy funding to achieve the highest-fidelity simulations of wind turbines and wind farms to date, with the goal of enabling disruptive changes to turbine and plant design and operation. Innovation will be gleaned through better understanding of the complex flow dynamics in wind farms, including wake evolution and the impact of wakes on downstream turbines and turbulent flow from complex terrain. High-fidelity predictive simulations employ hybrid turbulence models, geometry/boundary-layer-resolving CFD meshes, atmospheric turbulence, nonlinear structural dynamics, and fluid-structure interaction. While there is an emphasis on very high-fidelity simulations (e.g., blade resolved with full fluid-structure coupling), the ExaWind environment supports lower-fidelity modeling capabilities including actuator-line and -disk methods. Important in the development of ExaWind codes is that the codes scale well on today’s largest petascale supercomputers and on the next-generation platforms that will enable exascale computing.