bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of a Passive Flow Control Device in an S-Duct Inlet at High Subsonic Flow
Authors: Rider Courtney , Asghar Asad , Allan William D. E. , Ingram Grant , Stowe Robert , Pimentel Rogerio
Published: September 2021

This paper reports the investigation of a flow control strategy for an S-duct diffusers. The method incorporates stream-wise tubercles, and aims to enhance the performance of S-duct inlets by reducing the size and intensity of separated flow. These devices, bioinspired from humpback whale flippers’ leading edge protuberances, have been shown to be effective in increasing post-stall coefficients of lift of airfoils. In S-duct diffusers, the presence of convex curvature next to the separated region provides an ideal location for the installation of a tubercle-like device. The flow control effectiveness was evaluated by test-rig measurements and computational fluid dynamics (CFD) simulations of the flow in an S-duct at high subsonic flow conditions (Ma = 0.80). The S-ducts were rapid prototyped in plastic using 3D printing. Static surface pressure along the length and total pressure at the exit revealed pressure recovery, total pressure loss, swirl, and the nature of flow distortion at the S-duct exit. CFD simulations used ANSYS FLUENT with a RANS solver closed with the RKE turbulence model. The CFD simulation compared well with the test-rig data and provided useful information on flow mechanism and for understanding flow features. The performance of the baseline and variant with the flow control device was compared and flow control strategy was evaluated.
The Effect of Compressibility Factor on Turbine Performance
Authors: Baumgärtner David , Otter John J. , Wheeler Andrew P. S.
Published: September 2021

The compressibility factor Z is one of the most common properties that describes a fluid diversion from an ideal gas. Still, its effect on turbine performance is not well known. We determine a set of non-dimensional parameters that fix the gas dynamic behaviour, independent of Z, and thus isolate the effect that Z has on turbine performance. The results indicate that, contrary to the common perception, low values of Z and hence a strong diversion from an ideal gas lead to a reduction in loss for supersonic operating conditions, if all other non-dimensionals are accounted for. The aerodynamic mechanisms responsible are due to reductions in shock, boundary layer and trailing edge loss. The results from this paper are relevant for all future turbines operating with non-ideal working fluids.
Research on Fault Diagnosis of Steam Turbine Rotor Unbalance and Parallel Misalignment Based on Numerical Simulation and Convolutional Neural Network
Authors: Wang Chongyu , Zhang Di , Xie Yonghui
Published: September 2021

The steam turbine rotor is still the main power generation equipment. Affected by the impact of new energy on the power grid, the steam turbine needs to participate in peak load regulation, which will make turbine rotor components more prone to failure. The rotor is an important equipment of a steam turbine. Unbalance and misalignment are the normal state of rotor failure. In recent years, more and more attention has been paid to the fault detection method based on deep learning, which takes rotating machinery as the object. However, there is a lack of research on actual steam turbine rotors. In this paper, a method of rotor unbalance and parallel misalignment fault detection based on residual network is proposed, which realizes the end-to-end fault detection of rotor. Meanwhile, the method is evaluated with numerical simulation data, and the multi task detection of rotor unbalance, parallel misalignment, unbalanced parallel misalignment coupling faults (coupling fault called in this paper) is realized. The influence of signal-to-noise ratio and the number of training samples on the detection performance of neural network is discussed. The detection accuracy of unbalanced position is 93.5%, that of parallel misalignment is 99.1%. The detection accuracy for unbalance and parallel misalignment is 89.1% and 99.1%, respectively. The method can realize the direct mapping between the unbalanced, parallel misalignment, coupling fault vibration signals and the fault detection results. The method has the ability to automatically extract fault features. It overcomes the shortcoming of traditional methods that rely on signal processing experience, and has the characteristics of high precision and strong robustness.
Potential of Micro Gas Turbines to Provide Renewable Heat and Power in Off-Grid Applications for Desalination and Industrial Wastewater Treatment
Authors: Montes-Sánchez J. , de Weert B. , Petit B. , García-Rodríguez L. , Sánchez D.
Published: September 2021

The demand for all types of resources (food, freshwater, energy and raw materials) has increased alarmingly due to the continuous techno-economic development of society, bringing about a pressing shortage not only in low-income countries but also in more developed economies. Such is the case for the very wealthy countries in the Gulf Cooperation Council, which are currently struggling with the lack of fresh water supply, or certain countries in Latin America where the contamination of natural water sources poses a major environmental threat. In order to assess this water-energy nexus problem, this paper looks into systems where the production of renewable power is combined with either freshwater production (through desalination) or industrial wastewater treatment for effluent control. Three enabling renewable energy technologies are assessed: solar micro gas turbines, wind turbines and photovoltaic panels. In all cases, off-grid installations are considered.

The paper describes the characteristics of these three systems and provides a comparison of technical specifications, yield and costs. Wind and photovoltaic are the standard approach, as already proven by a number of commercial plants, but solar micro gas turbines exhibit additional flexibility (in particular when hybridisation is considered) and have the differential feature of producing not only electric power but also heat. This enables the combination of different types of water treatment technologies in order to increase water production/recovery which, in turn, reduces the environmental impact of the production process associated (either freshwater or other good or service).
Unlocking the Green Economy for Aeroderivative Gas Turbines
Authors: Corbett Nicholas C. , Houde Michel , Bohan Kathleen , Batt Simon
Published: September 2021

If existing gas turbine engines are to remain as the primary choice source of power for supplying short term peaking power capacity in an emergency, then they will need to be capable of directly using a alternative carbon neutral fuel supply. It is important that the fuel can be stored locally to ensure operation of the gas turbine can be provided without reliance upon supplies through distribution network infrastructure or stored hydrogen. Alternative carbon neutral fuels such as synthetic electro or biomass manufactured from hydrogen with nitrogen or CO2 to produce respectively; nitrofuel (Ammonia) or carbofuel (Methanol). Both fuels are renewable and compatible with existing carbon supply chain infrastructure as they can be similarly transported and stored as liquids with similar properties.

Digital technologies can help accelerate the uptake of carbon neutral solutions by operators by assisting them to make greener choices, from the data and information presented to them, promoting the use of their assets demonstrating their contribution and responsibilities to managing the environment. Whilst progress in adopting digital technology has been slow, it is by linking the investment to decarbonization that could then be considered as a value adder rather than a regulatory requirement.

The paper discusses the program of work to develop a bundle of digital services whilst decarbonizing aeroderivative gas turbine applications.
Condition Monitoring of Wind Turbines Based on the Scattering Transform of Vibration Data
Authors: Qi Junyu , Mauricio Alexandre , Gryllias Konstantinos
Published: September 2021

As a renewable, unlimited and free resource, wind energy has been intensively deployed in the past to generate electricity. However, the maintenance of Wind Turbines (WTs) can be challengeable. On the one hand, most wind farms operate in remote areas and on the other hand, the dimension of WTs’ tip/hub/rotor are usually enormous. In order to prevent abrupt breakdowns of WTs, a number of Condition Monitoring (CM) methods have been proposed. Focusing on bearing diagnostics, Squared Envelope Spectrum is one of the most common techniques. Moreover in order to identify the optimum demodulation frequency band, fast Kurtogram, Infogram and Sparsogram are nowadays popular tools evaluating respectively the Kurtosis, the Negentropy and the Sparsity. The analysis of WTs usually requires high effort due to the complexity of the drivetrain and the varying operating conditions and therefore there is still need for research on effective and reliable CM techniques for WT monitoring. Thus the purpose of this paper is to investigate a blind and effective CM approach based on the Scattering Transform. Through the comparison with state of the art techniques, the proposed methodology is found more powerful to detect a fault on six validated WT datasets.
Experimental Characterization of the Evolution of Global Flow Structure in the Passage of an Axial Compressor
Authors: Saraswat Ayush , Koley Subhra Shankha , Katz Joseph
Published: September 2021

Ongoing experiments conducted in a one-and-half stages axial compressor installed in the JHU refractive index-matched facility investigate the evolution of flow structure across blade rows. After previously focusing only on the rotor tip region, the present stereo-PIV (SPIV) measurements are performed in a series of axial planes covering an entire passage across the machine, including upstream of the IGV, IGV-rotor gap, rotor-stator gap, and downstream of the stator. The measurements are performed at flow rates corresponding to pre-stall condition and best efficiency point (BEP). Data are acquired for various rotor-blade orientations relative to the IGV and stator blades. The results show that at BEP, the wakes of IGV and rotor are much more distinct and the wake signatures of one row persists downstream of the next, e.g., the flow downstream of the stator is strongly affected by the rotor orientation. In contrast, under pre-stall conditions, the rotor orientation has minimal effect on the flow structure downstream of the stator. However, the wakes of the stator blades, where the axial momentum is low, are now wider. For both conditions, the flow downstream of the rotor is characterized by two regions of axial momentum deficit in addition to the rotor wake. A deficit on the pressure side of the rotor wake tip is associated with the tip leakage vortex (TLV) of the previous rotor blade, and is much broader at pre-stall condition. A deficit on the suction side of the rotor wake near the hub appears to be associated with the hub vortex generated by the neighboring blade, and is broader at BEP. At pre-stall, while the axial momentum upstream of the rotor decreases over the entire tip region, it is particularly evident near the rotor blade tip, where the instantaneous axial velocity becomes intermittently negative. Downstream of the rotor, there is a substantial reduction in mean axial momentum in the upper half of the passage, concurrently with an increase in the circumferential velocity. Consequently, the incidence angle upstream of the stator increases in certain regions by up to 30 degrees. These observations suggest that while the onset of the stall originates from the rotor tip flow, one must examine its impact on the flow structure in the stator passage as well.
Aerodynamic Characteristics of a Blended-Wing-Body Aircraft With A Serpentine Inlet Using Flow Control Techniques
Authors: Youn Min-Sik , Kim Youn-Jea
Published: September 2021

Demands of a modern aircraft regarding its aerodynamic performance and high efficiency are ever-growing. An S-shaped inlet, as known as a serpentine duct, plays a significant role in increasing fuel efficiency. Recently, the serpentine duct is commonly employed for military aircraft to block the front of the jet engine from radar. However, delivering a non-uniformly distorted flow to the engine face (aerodynamic interface plane, AIP) though a serpentine duct is inevitable due to the existence of flow separation and swirl flow in the duct. The effect of distortion is to cause the engine compressor to surge; thus, it may impact on the life-cycle of aircraft engine. In this study, aerodynamic characteristics of a serpentine duct mounted on a blended-wing-body (BWB) aircraft was thoroughly investigated to determine where and how the vortex flow was generated. In particular, both passive and active flow control were implemented at a place where the flow separation was occurred to minimize the flow distortion rate in the duct. The passive and active flow control systems were used with vortex generator (VG) vanes and air suctions, respectively. A pair of VG s have been made as a set, and 6 sets of VG in the serpentine duct. For the active flow control, 19 air suctions have been implemented. Both flow control devices have been placed in three different locations. To evaluate the performance of flow control system, it is necessary to quantify the flow uniformity at the AIP. Therefore, coefficient of distortion, DC(60) was used as the quantitative measure of distortion. Also, change in DC(60) value while the BWB aircraft is maneuvering phase was analyzed.
Accelerated Creep Test (ACT) Qualification of Creep-Resistance Using the WCS Constitutive Model and Stepped Isostress Method (SSM)
Authors: Cano Jaime A. , Stewart Calvin M.
Published: September 2021

In this study, a qualification of accelerated creep-resistance of Inconel 718 is assessed using the novel Wilshire-Cano-Stewart (WCS) model and the stepped isostress method (SSM) and predictions are made to conventional creep data. Conventional creep testing (CCT) is a long-term continuous process, in fact, the ASME B&PV III requires that 10,000+ hours of experiments must be conducted to each heat for materials employed in boilers and/or pressure vessel components. This process is costly and not feasible for rapid development of new materials. As an alternative, accelerated creep testing techniques have been developed to reduce the time needed to characterize the creep resistance of materials. Most techniques are based upon the time-temperature-stress superposition principle (TTSSP) that predicts minimum-creep-strain-rate (MCSR) and stress-rupture behaviors but lack the ability to predict creep deformation and consider deformation mechanisms that occur for experiments of longer duration. The stepped isostress method (SSM) has been developed which enables the prediction of creep deformation response as well as reduce the time needed for qualification of materials. The SSM approach has been successful for polymer, polymeric composites, and recently has been introduced for metals. In this study, the WCS constitutive model, calibrated to SSM test data, qualifies the creep resistance of Inconel 718 at 750°C and predictions are compared to CCT data. The WCS model has proven to make long-term predictions for stress-rupture, minimum-creep-strain-rate (MCSR), creep deformation, and damage in metallic materials. The SSM varies stress levels after time interval adding damage to the material, which can be tracked by the WCS model. The SSM data is calibrated into the model and the WCS model generates realistic predictions of stress-rupture, MSCR, damage, and creep deformation. The calibrated material constants are used to generate predictions of stress-rupture and are post-audit validated using the National Institute of Material Science (NIMS) database. Similarly, the MCSR predictions are compared from previous studies. Finally the creep deformation predictions are compared with real data and is determined that the results are well in between the expected boundaries. Material characterization and mechanical properties can be determined at a faster rate and with a more cost-effective method. This is beneficial for multiple applications such as in additive manufacturing, composites, spacecraft, and Industrial Gas Turbines (IGT).
Effects of Eight Methods and Five Steps of Tai Chi Practice on Balance Control Among Older Adults
Authors: Hu Xiu , Lyu Shaojun , Mao Min , Zhang Jianwei , Sun Wei , Zhang Cui , Song Qipeng
Published: September 2021

The team developed the newly compiled eight methods and five steps of Tai Chi (EMFSTC), which includes introductory routines to Tai Chi characterized by simple structures. This study examined the effectiveness of EMFSTC practice on balance control. A total of 31 participants were randomly assigned to EMFSTC (n = 15, age = 66.4 ± 1.7 years, received 16-week EMFSTC practice) or control (n = 16, age = 66.7 ± 1.8 years, received no practice) groups. Significant group by training interactions were observed. After EMFSTC practice, balance control improved, as indicated by decreased root mean square and mean velocity of center of pressure, proprioception threshold during knee extension, and plantar tactile sensitivity threshold at the arch. EMFSCT can be an effective rehabilitation modality to improve balance control among older adults.
“I Don’t Know How You Get Past That”: Racism and Stereotyping in College Football Recruiting Media
Authors: Love Adam , Winemiller Sam , Harrison Guy , Stamm Jason
Published: September 2021

College football programs invest millions of dollars into recruiting top high school prospects. This recruiting process is covered extensively by reporters from sports media outlets. While the players being recruited are predominately Black, the sports media is disproportionately dominated by White men. In this context, the current study reports on data from interviews with 15 participants who work in the college football recruiting media industry. While some participants adopted a color-blind perspective dominated by a belief that racism no longer exists, most reporters expressed an awareness of racial stereotypes in the sports media and felt a need to address racial inequity. Such awareness presents an opportunity for anti-racist training that may help media members avoid racial stereotyping and address racism in the field.
Social evolution in mammals
Authors: Clutton-Brock Tim
Published: September 2021

Mammal societies

Although a few types of structures prevail, social systems among mammals are relatively varied. New techniques, from monitoring to genetics, have allowed for a deeper understanding of this variation, how it is related to the environment, and how it has evolved. Clutton-Brock reviews the forms of and drivers of the different types of breeding systems and how they have been shaped by ecology and history. The author discusses how mammalian social interactions may be affected by human activities that are driving environmental change. —SNV
Three-dimensional capillary ratchet-induced liquid directional steering
Authors: Feng Shile , Zhu Pingan , Zheng Huanxi , Zhan Haiyang , Chen Chen , Li Jiaqian , Wang Liqiu , Yao Xi , Liu Yahua , Wang Zuankai
Published: September 2021

Surfaces directing fluid flows

Although surfaces can be made to attract or repel liquids using coatings, surface textures with specific curvature can also be used to achieve the same effect. However, fluid transport is usually limited by the specific pattern that only drives flow at the surface itself. Feng
et al
. created a dual-reentrant surface that has an asymmetric profile so that fluids spread out at the surface and subsurface layers. Furthermore, these surfaces can be designed so that different liquids will naturally steer in opposing directions simply because of their specific interactions with the surface. —MSL
Innovation, entrepreneurship, promotion, and tenure
Authors: Carter Rich G. , Mundorff Karl , Risien Julie , Bouwma-Gearhart Jana , Bratsch-Prince Dawn , Brown Sandra A. , Campbell Almesha L. , Hartman Joseph C. , Hasemann Charles A. , Hollenbeck Peter J. , Lupiani Blanca , McCarty Owen J. T. , McClure Ian D. , Mealey Katrina , Mimura Carol , Romero Andrea J. , Sztajn Paola , Van Egeren Laurie
Published: September 2021

Academic incentives must reward broader societal impacts
Multiple Copies offlhDCin Paraburkholderia unamae Regulate Flagellar Gene Expression, Motility, and Biofilm Formation
Authors: Thai Shelley N.-M. , Lum Michelle R. , Naegle Jeanine , Onofre Michael , Abdulla Hassan , Garcia Allison , Fiterz Andreh , Arnell Ashley , Lwin Thuthiri T. , Kavanaugh Aaron , Hikmat Zade , Garabedian Nora , Ngo Ryan Toan , Dimaya Brenda , Escamilla Adan , Barseghyan Luiza , Shibatsuji Maria , Soltani Salma , Butcher Luke , Hikmat Firas , Amirian Dro , Bazikyan Artin , Brandt Nathan , Sarkisian Mary , Munoz Xavier , Ovakimyan Andrew , Burnett Emily , Pham Jennifer Ngoc , Shirvanian Ania , Hernandez Roberto , Vardapetyan Maria , Wada Matthew , Ramirez Cuauhtemoc , Zakarian Martin , Billi Fabrizio
Published: September 2021

Motility is important in the colonization of plant roots by beneficial and pathogenic bacteria, with flagella playing essential roles in host cell adhesion, entrance, and biofilm formation. Flagellar biosynthesis is energetically expensive.
Crustal deformation and exhumation within the India-Eurasia oblique convergence zone: New insights from the Ailao Shan-Red River shear zone
Authors: Zhang B. , Chen S.Y. , Wang Y. , Reiners P.W. , Cai F.L. , Speranza F. , Zhang J.J. , Zhong D.L. , Liu K.
Published: September 2021

During the collision of India and Eurasia, regional-scale strike-slip shear zones played a key role in accommodating lateral extrusion of blocks, block rotation, and vertical exhumation of metamorphic rocks as presented by deformation on the Ailao Shan-Red River shear zone (ARSZ) in the Eastern Himalayan Syntaxis region and western Yunnan, China. We report structural, mica Ar/Ar, apatite fission-track (AFT), and apatite (U-Th)/He (AHe) data from the Diancangshan massif in the middle segment of the ARSZ. These structural data reveal that the massif forms a region-scale antiform, bordered by two branches of the ARSZ along its eastern and western margins. Structural evidence for partial melting in the horizontal mylonites in the gneiss core document that the gneiss experienced a horizontal shear deformation in the middle crust. Muscovite Ar/Ar ages of 36–29 Ma from the core represent cooling ages. Muscovite Ar/Ar ages of 25 and 17 Ma from greenschist-facies mylonites along the western and southern shear zones, respectively, are interpreted as recording deformation in the ARSZ. The AFT ages, ranging from 15 to 5 Ma, represent a quiescent gap with a slow cooling/exhumation in the massif. AHe results suggest that a rapid cooling and final exhumation episode of the massif could have started before 3.2 Ma, or likely ca. 5 Ma, and continue to the present. The high-temperature horizontal shearing layers of the core were first formed across the Indochina Block, locally antiformed along the tectonic boundaries, and then cooled through the mica Ar-Ar closure temperature during Eocene or early Oligocene, subsequently reworked and further exhumed by sinistral strike-slip movement along the ARSZ during the early Oligocene (ca. 29 Ma), lasting until ca. 17 Ma, then final exhumation of the massif occurred by dextral normal faulting on the Weixi-Qiaohou and Red River faults along the limbs of the ARSZ since ca. 5 Ma. The formation of the antiform could indicate local crustal thickening in an early transpressional setting corresponding to India-Asia convergence. Large-scale sinistral ductile shear along the ARSZ in the shallow crust accommodated lateral extrusion of the Indochina Block, and further contributed to the vertical exhumation of the metamorphic massif from the late Oligocene to the middle Miocene. Furthermore, the change of kinematic reversal and associated cooling episodes along the ARSZ since the middle Miocene or early Pliocene imply a tectonic transfer from strain localization along the major tectonic boundaries to continuous deformation corresponding to plateau growth and expansion.
Diversification of Archean tonalite-trondhjemite-granodiorite suites in a mushy middle crust
Authors: Kendrick Jillian , Duguet Manuel , Yakymchuk Chris
Published: September 2021

Tonalite-trondhjemite-granodiorite (TTG) suites are the dominant component of Earth's first continents, but their origins are debated. The trace element concentrations of these rocks are conventionally linked to their source depths and inferred geodynamic settings with the implicit assumption that TTG compositions are source-controlled. Alternatively, their variable compositions may be caused by fractional crystallization in TTG plutons after emplacement and less clearly linked to source depth. Most TTGs in Archean mid-crustal exposures are the dominant component of igneous gray gneiss complexes; the processes that influence the evolution of TTG magmas in this setting are poorly understood. We present a petrological–geochemical model that explains the coexistence of TTGs in the middle crust with low-pressure and high-pressure geochemical trends, irrespective of tectonic setting or depth of the TTG source. We propose that mid-crustal TTGs were long-lived crystal mushes with compositions controlled by the separation of early-crystallizing plagioclase and melt. Using phase equilibrium modeling, we demonstrate that a suite of TTGs from the southern Superior Province in Canada represents variably plagioclase-rich and melt-rich fractions from a common parent magma. The behavior of plagioclase may have a strong influence on the geochemical trends of TTGs, including the degree of rare earth element fractionation. Our results suggest that trace element compositions of TTGs may not primarily reflect the depth of the source and cannot be used alone to infer Archean geodynamic settings.
Mantle heating at ca. 2 Ga by continental insulation: Evidence from granites and eclogites
Authors: Tamblyn R. , Hasterok D. , Hand M. , Gard M.
Published: September 2021

Igneous and metamorphic rocks contain the mineralogical and geochemical record of thermally driven processes on Earth. The generally accepted thermal budget of the mantle indicates a steady cooling trend since the Archean. The geological record, however, indicates this simple cooling model may not hold true. Subduction-related eclogites substantially emerge in the rock record from 2.1 Ga to 1.8 Ga, indicating that average mantle thermal conditions cooled below a critical threshold for widespread eclogite preservation. Following this period, eclogite disappeared again until ca. 1.1 Ga. Coincident with the transient emergence of eclogite, global granite chemistry recorded a decrease in Sr and Eu and increases in yttrium and heavy rare earth element (HREE) concentrations. These changes are most simply explained by warming of the thermal regime associated with granite genesis. We suggest that warming was caused by increased continental insulation of the mantle at this time. Ultimately, secular cooling of the mantle overcame insulation, allowing the second emergence and preservation of eclogite from ca. 1.1 Ga until present.
Supplemental Material: Stratigraphy of the Eocene–Oligocene Titus Canyon Formation, Death Valley, California, and Eocene extensional tectonism in the Basin and Range
Authors: Midttun N. , al. et
Published: September 2021

Plate 1. Ten correlated graphical measured sections of the Titus Canyon Formation. Plate should be viewed at 24 inches wide by 36 inches tall. Plate 2. Geologic map of the southern Grapevine Mountains and northern Funeral Mountains, with an emphasis on Cenozoic stratigraphy. Plate is intended to be viewed at 50 inches wide and 40 inches tall.
Transoral robotic resection of a lingual thyroid: a novel treatment for obstructive sleep apnoea
Authors: Curtis Jon , Walford Sophie , Howe David
Published: September 2021

A 34-year-old woman with a history of congenital hypothyroidism and 15 years of obstructive sleep apnoea was admitted with a left submandibular swelling secondary to a dental infection. A CT scan of the neck identified an incidental 27 mm tongue base mass and the absence of any cervical thyroid tissue. This mass was not observable on examination of the oropharynx but was seen on fine nasendoscopy while thyroid function tests showed good thyroid stimulating hormone suppression. Her acute dental infection was treated and, following multidisciplinary team discussion, she was diagnosed with an ectopic lingual thyroid. She was offered different management options including no intervention and radio-iodide treatment but opted for transoral robotic resection. The lesion was resected en bloc with clear margins and histology confirmed lingual thyroid tissue. Since the procedure, she has remained free of sleep apnoea with a significantly improved quality of life.
Neonatal giant dural sinus ectasia: a multimodality imaging approach
Authors: Zuniega Ralph Rommualdo Abareta , Santos Julian Alejandro , Galsim Romelito Jose Galvan , Elevazo Jonathan Saputil
Published: September 2021

Dural venous sinus ectasia is a rare anomaly characterised by the formation of a large vascular lake within the leaves of the dural sinuses, usually associated with thrombosis. These lesions can cause brain compression, cardiac insufficiency and disseminated intravascular coagulation, which may lead to poor prognosis. We present the case of a neonate who presented with an intracranial mass on prenatal ultrasound. Postnatal transcranial ultrasonography, cranial CT and cranial MRI demonstrated a large lesion predominantly occupying the dural sinus confluence, extending into the sagittal sinus, straight sinus and right transverse sinus. The left marginal sinus remains unfused and patent. Concomitant arteriovenous malformations were evident in the median interhemispheric fissure and the left Sylvian fissure. There are several published case reports and case series describing malformations of the dural sinuses in perinatal and neonatal patients in recent years, but this case is unique in that: (1) there is the presence of a vascular malformation concomitant to the dural sinus ectasia and (2) it highlights the importance of imaging in clinching the diagnosis of giant dural venous sinus ectasia, as it is often misdiagnosed as more common conditions such as extra-axial intracranial haemorrhage.
Buschke-Löwenstein tumour: a rare and challenging entity
Authors: Costa Almeida Carlos Eduardo , Azevedo José , Botelho Inês , Vilaça Jaime
Published: September 2021

Buschke-Löwenstein tumour (BLT) is rare and locally aggressive, and malignant transformation is a possibility. Because there is no consensus on the best treatment approach, the authors present a treatment algorithm based on several case reports. A 57-year-old male patient resorted to surgical consultation with a giant perianal cauliflower-like mass. A BLT was diagnosed. Due to the involvement of the anal sphincter, a wide local excision saving the rectum failed. Abdominoperineal resection was performed. Malignant transformation was diagnosed, and adjuvant radiotherapy was delivered. Clinical evolution was uneventful. Aggressive behaviour despite the absence of malignancy is the hallmark of BLT. The common presentation is an anal mass with a cauliflower-like appearance. Anal verrucous carcinoma and squamous cell carcinoma are the major differential diagnoses. BLT treatment is challenging. Surgery is the first-line treatment, raging from wide local excision to abdominoperineal resection. To improve outcomes, chemoradiation can be used in combination with surgery. Long-term follow-up is mandatory.
Atypical presentation of intravascular leiomyomatosis mimicking advanced uterine sarcoma: modified laterally extended endopelvic resection with preservation of pelvic neural structures
Authors: Cowie Philip , Eastwood Ben , Smyth Sarah , Soleymani majd Hooman
Published: September 2021

Intravascular leiomyomatosis is a rare, benign tumour of myometrial smooth muscle. Despite being non-invasive, these tumours can proliferate aggressively within vascular structures including pelvic vessels, the vena cava and the heart. We discuss a 77-year-old woman presenting with a 9 cm uterine mass extending into the right adnexa and ovarian vein. Following hysteroscopic biopsy, palliative radical surgical resection was performed for suspected stage IV leiomyosarcoma. Tumour extension into the pelvic sidewall and obturator fossa indicated a modified laterally extended endopelvic resection combined with skeletonisation and preservation of the pelvic neurovasculature, ultimately providing a curative procedure with minimal functional neurological morbidity. We present this unusual case to assist in the development of a consensus for optimal case management where formal guidelines are not yet available. We summarise current understanding of intravascular leiomyomatosis and highlight the value of advanced surgical techniques using knowledge of complex ontogenetic and pelvic neuroanatomy in its management.
Biomass models for three species with different growth forms and geographic distribution in the Brazilian Atlantic forest
Authors: Uller Heitor Felippe , Oliveira Laio Zimermann , Klitzke Aline Renata , de Freitas Joberto Veloso , Vibrans Alexander Christian
Published: September 2021

Allometric models embedding independent variables such as diameter at breast height (d) and total height (h) are useful tools to predict the biomass of individual trees. Models for tropical forests are often constructed based on datasets composed of species with different morphological features and architectural models. It is reasonable to expect, however, that species-specific models may reduce uncertainties in biomass predictions, especially for palms, tree ferns, and trees with peculiar morphological features, such as stilt roots and hollow trunks. In this sense, three species with wide geographical distribution in the Brazilian Atlantic Forest were sampled, namely Euterpe edulis Mart., Cyathea delgadii Sternb., and Cecropia glaziovii Snethl., with the aim to (i) quantify their aboveground biomass (AGB), (ii) evaluate the AGB distribution in different plant compartments, (iii) fit species-specific models for predicting AGB at the individual level, and (iv) assess the performance of specific and generic models available in the literature to predict the AGB of individuals of these species. The compartment stem represented, on average, ∼74% of the total AGB of E. edulis individuals; in turn, the caudex compartment of C. delgadii represented, on average, ∼87% of the total AGB, while the trunk compartment of C. glaziovii represented, on average, ∼74%. Among the fitted models, the power model [Formula: see text] showed the best performance for E. edulis and C. delgadii. In turn, the asymptotic logistic model [Formula: see text], where dc is the diameter above the upper stilt root, presented the best performance for C. glaziovii. The variable h appeared as the most important predictor of AGB of E. edulis and C. delgadii; in contrast, the stem and caudex mean basic specific gravities were not suitable predictors. The fitted species-specific models outperformed the specific and generic models selected from the literature. They may, therefore, contribute to the reduction of uncertainties in AGB estimates. In addition, the results support evidence that specific models may be necessary for species with different growth forms and (or) peculiar morphological features, especially those with great abundance and wide geographic distribution.
Investigation of phage and molasses interactions for the biocontrol ofE. coliO157:H7
Authors: Evran Sefika , Tayyarcan Emine Kubra , Acar-Soykut Esra , Guven Burcu , Durakli-Velioglu Serap , Boyaci Ismail Hakki
Published: September 2021

Resistance to antibiotics is one of the most critical health problems in the world. Therefore, finding new treatment methods to be used as alternatives to antibiotics has become a priority for researchers. Similar to phages, certain products containing antimicrobial components, such as molasses, are widely used to eliminate resistant bacteria. Molasses has a strong antimicrobial effect on bacterial cells, and this effect is thought to be due to the breakdown of the cytoplasmic cell membrane and cell proteins of the polyphenols in molasses. In the present study, phage–molasses interactions were investigated to examine the effects of concomitant use. It was found that molasses samples increased the size of phage plaques by up to 3-fold, and MIC and 1/2 × MIC concentrations of molasses increased the burst size of phages. Although no synergistic effect was found between the phage and molasses, the antimicrobial activities of the components and the effect of molasses on phage activity were demonstrated.
Probing variation of the fine-structure constant in runaway dilaton models using Strong Gravitational Lensing and Type Ia Supernovae
Authors: Colaço L. R. , Holanda R. F. L. , Silva R.
Published: September 2021

In order to probe a possible time variation of the fine-structure constant ($$\alpha $$
α
), we propose a new method based on Strong Gravitational Lensing and Type Ia Supernovae observations. By considering a class of runaway dilaton models, where $$\frac{\Delta \alpha }{\alpha }= - \gamma \ln {(1+z)}$$

Δ
α

α

=
-
γ
ln

(
1
+
z
)

, we obtain constraints on $$\frac{\Delta \alpha }{\alpha }$$

Δ
α

α

at the level $$\gamma \sim 10^{-2}$$

γ
∼

10

-
2

($$\gamma $$
γ
captures the physical properties of the model). Since the data set covers the redshift range $$0.075 \le z \le 2.2649$$

0.075
≤
z
≤
2.2649

, the constraints derived here provide independent bounds on a possible time variation of $$\alpha $$
α
at low, intermediate and high redshifts.
Parameters optimization based on neural network of practical wavelength division multiplexed decoy-state quantum key distribution
Authors: Li Jia-Hao , Shi Lei , Li Tian-Xiu , Xue Yang , Zhang Zhi-Yun , Tang Jie
Published: September 2021

The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.
ON A CLASS OF FRACTIONAL HARDY-TYPE INEQUALITIES
Authors: WU SHANHE , SAMRAIZ MUHAMMAD , IQBAL SAJID , RAHMAN GAUHAR
Published: September 2021

In this paper, we study a new class of Hardy-type inequalities involving fractional calculus operators. We derive the Hardy-type inequalities for the variant of Riemann–Liouville fractional calculus operators and [Formula: see text]-Hilfer fractional derivative operator. The obtained inequalities involving fractional operators are more general as compared to some existing results in the literature.
Comparison Between A* and RRT Algorithms for 3D UAV Path Planning
Authors: Zammit Christian , van Kampen Erik-Jan
Published: September 2021

This paper aims to present a comparative analysis of the two most utilized graph-based and sampling-based algorithms and their variants, in view of 3D UAV path planning in complex indoor environment. The findings of this analysis outline the usability of the methods and can assist future UAV path planning designers to select the best algorithm with the best parameter configuration in relation to the specific application. An extensive literature review of graph-based and sampling-based methods and their variants is first presented. The most utilized algorithms which are the A* for graph-based methods and Rapidly-Exploring Random Tree (RRT) for the sampling-based methods, are defined. A set of variants is also developed to mitigate with inherent shortcomings in the standard algorithms. All algorithms are then tested in the same scenarios and analyzed using the same performance measures. The A* algorithm generates shorter paths with respect to the RRT algorithm. The A* algorithm only explores volumes required for path generation while the RRT algorithms explore the space evenly. The A* algorithm exhibits an oscillatory behavior at different resolutions for the same scenario that is attenuated with the novel A* ripple reduction algorithm. The Multiple RRT generated longer unsmoothed paths in shorter planning times but required more smoothing over RRT. This work is the first attempt to compare graph-based and sampling-based algorithms in 3D path planning of UAVs. Furthermore, this work addresses shortcomings in both A* and RRT standard algorithms by developing a novel A* ripple reduction algorithm, a novel RRT variant and a specifically designed smoothing algorithm.
Exploring LoRa for Sensing
Authors: Zhang Fusang , Chang Zhaoxin , Xiong Jie , Zhang Daqing
Published: September 2021

Wireless sensing received a great amount of attention in recent years and various wireless technologies have been exploited for sensing, including WiFi [1], RFID [2], ultrasound [3], 60 GHz mmWave [4] and visible light [5]. The key advantage of wireless sensing over traditional sensing is that the target does not need to be equipped with any sensor(s) and the wireless signal itself is being used for sensing. Exciting new applications have been enabled, such as passive localization [6] and contactless human activity sensing [7]. While promising in many aspects, one key limitation of current wireless sensing techniques is the very small sensing range. This is because while both direct path and reflection path signals are used for communication, only the weak target-reflection signals can be used for sensing. Take Wi-Fi as an example: the communication range can reach 20 to 50 meters indoors but its sensing range is merely 4 to 8 meters. This small range further limits the through-wall sensing capability of Wi-Fi. On the other hand, many applications do require long-range and through-wall sensing capability. In a fire rescue scenario, the sensing device cannot be placed close to the building, and the long-range through-wall sensing capabilities are critical for detecting people deep inside the building. Table I summarizes the sensing range of existing wireless technologies. We can see that long-range through-wall sensing is still missing with wireless sensing.
Static Analysis at GitHub
Authors: Clem Timothy , Thomson Patrick
Published: September 2021

The Semantic Code team at GitHub builds and operates a suite of technologies that power symbolic code navigation on github.com. We learned that scale is about adoption, user behavior, incremental improvement, and utility. Static analysis in particular is difficult to scale with respect to human behavior; we often think of complex analysis tools working to find potentially problematic patterns in code and then trying to convince the humans to fix them. Our approach took a different tack: use basic analysis techniques to quickly put information that augments our ability to understand programs in front of everyone reading code on GitHub with zero configuration required and almost immediate availability after code changes.
High-Performance Core-Shell Structured SiOx@Si-Silicide Nanocomposite Anode Material for Lithium-Ion Rechargeable Batteries
Authors: Reddyprakash Maddipatla , Loka Chadrasekhar , Lee Ryun Kyeong , Lee Kee-Sun
Published: September 2021

Si-based materials are the most promising anode candidates for high-performance and safe lithium-ion batteries (LIBs). However, their successful practical utilization is hampered due to the large volume variations during the alloying/dealloying process, structural instability, and poor conductivity. To address these issues, herein, we report a novel double-protection strategy for Si with a mechanically strengthen and conductive FeSi2 phase and SiOx core–shell structure (SiOx@Si-FeSi2 nanocomposite) synthesized via induction melting followed by high-energy mechanical milling and thermal oxidation. A high initial cycle coulombic efficiency (∼79%) and high reversible capacity of ∼843 mAh/g@220th cycle (under 1C-rate = 0.5 A g−1) is achieved for the SiOx@Si-FeSi2 nanocomposite. Moreover, high average coulombic efficiency of ∼99.1% and high reversible capacity retention of ∼80% (at 1C-rate) over 200 cycles; and excellent rate capability is obtained. The outstanding electrochemical performance of the SiOx@Si-FeSi2 nanocomposite is attributed to the synergistic effect of well dispersed active Si in the FeSi2 phase. Additionally, an amorphous SiOx core–shell structure significantly reduces the mechanical stresses/strains experienced by Si during lithiation/delithiation. It also provides a stable solid electrolyte interface and good conductivity. Subsequently, this facile, cost-effective synthetic approach providing excellent electrochemical performance makes the SiOx@Si-FeSi2 nanocomposite a promising anode material for high-performance LIBs.
A processual view on the use of problem-based learning in high school physiology teaching
Authors: de Pinho Luis Antonio , Alves Luiz Anastácio , Comarú Michele Waltz , Luz Maurício Roberto Motta Pinto da , Lopes Renato Matos
Published: September 2021

In problem-based learning (PBL), the steps and processes present in the PBL tutorial cycle are essential for constructive, self-directed, collaborative, and contextual student learning. This article presents a procedural study of a PBL tutorial cycle with high school students new to the method regarding human respiration and circulation physiology. We observed group dynamics and the learning process that occurred throughout the PBL tutorial cycle. The results indicate that conceptual changes were close to the planned learning objectives and that students enjoyed studying applying PBL. Moreover, a positive correlation was observed between group dynamics, self-directed learning and learning outcomes. Our results provide grounds for restructuring the tutorial cycle, especially important for novice PBL students, such as problem reformulation and the development and diversification of applied learning scaffolds. We conclude that the qualitative analysis performed herein can yield a deeper understanding of the PBL tutorial cycle and may be used to foster PBL implementation in institutions with little experience with the method and monitor its outcomes in organizations with mature PBL use.