bluuebunny/crossref_metadata_2025 huggingface dataset:
Refinement of a High Cycle Fatigue Decision-Gate Assessment for Additively Repaired Blades
Authors: Scott-Emuakpor Onome , Runyon Brian , Gillaugh Daniel , Smith Lucas , Johnson Philip
Published: October 2022

A recently developed high cycle fatigue (HCF) Acceptance Criteria demonstrates effectiveness in assessing the viability of two laser directed energy deposition (DED) repair processes on Titanium 6Al-4V (Ti 6Al-4V) fan blades. The assessment of these repairs requires a keen understanding of the average HCF behavior and the associated empirical data distribution. Specifically, detailed observations of the HCF regression behavior, stress amplitude dataset distribution, porosity size and distribution, and crack nucleation and propagation life are necessary. The amalgamation of these observations leads to information that quantifiably compares predicted fatigue life and data reliability of repaired blades to baseline blades within a percentage margin of acceptability. Despite a demonstration of the effectiveness of the HCF Acceptance Criteria, additional factors need to be considered to include available material or component information and nondestructive evaluation (NDE) conditional acceptance. This study explores the rigidity of the HCF Acceptance Criteria by applying it to Laser DED repaired turbine engine fan blades. The results help define a prior rule (entrance statement) that identifies expected results based on manufacturing/microstructure information as well as a second-tier rule incorporating NDE for a more refined HCF Acceptance criteria.
Design and Testing of a 275 Bar 700 Degree Celsius Expander for an Integrally Geared Supercritical CO2 Compander
Authors: Wilkes Jason , Robinson Kyle , Wygant Karl , Pelton Rob , Bygrave Jonathan
Published: October 2022

An integrally-geared (IG) compressor-expander (compander) for use in a nominal 10 MW-scale concentrated solar power (CSP) supercritical carbon dioxide (sCO2) plant application was designed, manufactured, and tested. The integrally-geared compander (IGC) developed for this application comprises multiple pinion shafts interacting through a single bull gear to create a compact package and utilize a low-cost, low-speed driver.

The present work will detail the design of the high-pressure high-temperature expander casing on an integrally geared frame, and illustrate how the project successfully mitigated the risk of fatigue and creep while allowing for rapid thermal transients in the design. Furthermore, test data from the test campaign will be presented supporting the analysis. Test results also show temperature profiles during operation exceeding 720° Celsius.
Printability and Overall Cooling Performance of Additively Manufactured Holes With Inlet and Exit Rounding
Authors: Veley Emma M. , Thole Karen A. , Furgeson Michael T. , Bogard David G.
Published: October 2022

To improve cooling effectiveness of gas turbine hardware, various film cooling hole shapes have previously been researched. Unique design modifications have recently been made possible through the design freedom allotted by additive manufacturing. As one example, creating a rounded inlet for a film-cooling hole can mitigate separation at the inlet. This study explores various geometric features by exploiting the uses of additive manufacturing for shaped film cooling holes at engine scale. Both printability and cooling performance were evaluated.

Resulting from this study, additively manufactured holes with hole inlet and exit rounding were printed with some variations from the design intent. The largest deviations from the design intent occurred from dross roughness features located on the leeward side of the hole inlet. The measured overall effectiveness indicated that an as-built inlet fillet decreased in-hole convection as well as decreased jet mixing compared to the as-built sharp inlet. Including an exit fillet, which prevented an overbuilt diffuser exit, was also found to decrease jet mixing. A particular insight gained from this study is the importance of the convective cooling within the hole to the overall cooling performance. In-hole roughness, which is a result of additive manufacturing, increased convective cooling within the holes but also increased jet mixing as the coolant exited the hole. The increased jet mixing caused low overall effectiveness downstream of injection.
Tip Flow Control in Optimized Large Gas Turbine Compressor Blading
Authors: Hummel Katja , Streit Anton , Peitsch Dieter
Published: October 2022

In transonic axial compressors of gas turbines, casing treatments (CTs) have the capability to improve the stability and delay stall. A full comprehension of the stall mechanism is essential to design a beneficial CT. Tip stall is a prerequisite. Most CT investigations and publications investigate flight propulsion applications. There is a need for detailed investigations in stationary large gas turbines concerning stability optimization. Typically, the tip gaps in the front stages are — relative to the blade span — by one magnitude smaller than for aero engines. This is due to the large absolute dimensions.

The goal of the present study is to increase the operating range towards stall without losing efficiency at design point conditions. Axisymmetric active and passive CT types are investigated.

The model is based on an optimized tip critical rotor design, which matches the boundary conditions of a large gas turbine. Most other investigations from the last decades are conducted for known airfoil shapes that were not automatically optimized for their operating conditions. A tip flow control was developed to improve the stability limits. The numerical investigations are carried out on a single rotor optimization using RANS simulations.

The study investigates in depth the ability of axisymmetric grooves with and without mass injection to postpone stall. It is shown why passive circumferential grooves do not improve the stability for the specific blade geometry. It is essential to quantify the influence of the axisymmetric types of CT onto the rotor tip flow especially for near stall conditions. Of particular interest is how the circumferential grooves perform when used in combination with mass injection. The results show that for this aerodynamically optimized rotor, a mass injection is needed to energize the tip leakage and therefore reduce the blockage. Passive circumferential grooves do not increase the stability. The injection of 1% stall mass flow rises the stall margin by 15% only with little losses.
Shrinkage Prediction Using Machine Learning for Additively Manufactured Ceramic and Metallic Components for Gas Turbine Applications
Authors: Warren Peter , Raju Nandhini , Krsmanovic Milos , Ebrahimi Hossein , Kapat Jayanta , Subramanian Ramesh , Ghosh Ranajay
Published: October 2022

Additive manufacturing of metallic and ceramic components can provide several benefits for gas turbines. This technology can help to decrease time and cost required for prototyping of both operational components and assistive tooling equipment. There are currently many methodologies for metallic and ceramic material printing, and these processes typically involve a sintering phase during the manufacturing procedure. The amount of shrinkage that occurs is dependent upon the sintering oven conditions, the printed material, and the geometry of the printed component. These factors can be broken down into many subfactors leading to an equation that is too complex and with too many variables to be solved in an analytical matter. Additive manufacturing can provide the ability to rapidly manufacture geometrically specific components for turbomachinery operations. To increase the accuracy of the geometric dimensions of the final product, the sintering shrinkage must be accurately predicted. Machine learning can assist by using data-driven approaches to ensure accurate prediction of shrinkage. This ultimately will increase the dimensional accuracy of the printed components. If there is an accurate shrinkage prediction formula that accounts for the material type, sintering oven conditions, and geometric specifications, the components can be scaled up in CAD (computer aided design) software prior to 3D printing and entering the sintering oven. This predictive capability will allow the end user to create dimensionally accurate parts at a rate that has not yet been possible. In this work, a machine learning approach is developed for the prediction of shrinkage during sintering of additive manufactured components. This paper uses a combination of experimental data and artificially generated data to create a framework for implementing linear regression tools to predict sintering trajectories. An accurate knowledge of the sintering trajectory for a given material can allow for more user control over the final properties and geometrical accuracy of a given component.
Wake Structure in Yawed Approaching Flows for an Axial-Flow Wind Turbine
Authors: Ahmadi Mohammad H. B. , Yang Zhiyin
Published: October 2022

Effects of yawed wind turbines on the wake structure are not fully understood. To obtain a better understanding, numerical studies of a small-scale three-bladed horizontal axis wind turbine at TSR = 6.7 with yaw angles of zero, 15°, 30° and 45° have been carried out to investigate the wake characteristics of the turbine in the near- and farwake. A hybrid approach coupling Large Eddy Simulation (LES) with Actuator Line Modelling (ALM) has been employed in the present study. The predicted results confirm the previous finding that the turbine wake is asymmetric under yawed approaching flows and the wake is inclined to the direction where the rotor is yawed. The present work further demonstrates that at high yaw angles the main wake may be divided into two smaller parallel wakes further downstream that are not symmetric suggesting a dependency on the turbine rotation direction. This study quantitatively explains how the non-uniform variations of radial velocity components at the turbine plane caused by the yawed flows result in the wake deflection and intersection of hub and blade tip vortices further downstream which leads to the wake splitting at high yaw angles.
The Influence of Turbulence and Reynolds Number on Endwall Heat Transfer in a Vane Cascade
Authors: Yel Mahi Maliha , Chukwuemeka Emmanuel , Donovan Shaun , Ames Forrest , Kanani Yousef , Acharya Sumanta
Published: October 2022

Endwall heat transfer measurements have been acquired in a vane cascade over a range of turbulence conditions and Reynolds numbers using an array of small commercial infrared (IR) cameras. The linear cascade was tested over five inlet turbulence conditions ranging from low turbulence (0.7%) to high turbulence (17.4%) and three exit chord Reynolds numbers ranging from 500,000 to 2,000,000. The small commercial IR cameras made by Therm-App have a resolution of 384 by 288 pixels and were connected to individual smart phones to record the images. The cascade was modified with small zinc selenide windows to provide IR access for the cameras. The five cameras were calibrated against a constant temperature test plate and the output images were adjusted for the fisheye effect and thermal droop at the edges. The large-scale low-speed cascade, used in the endwall heat transfer study, was configured in a four vane three full passage arrangement. The vane design includes a large leading and aft loading. This same cascade has been used in the acquisition of vane surface heat transfer distributions, vane suction surface heat transfer visualizations, and vane surface film cooling distributions. This paper includes comparisons with two LES calculations, which were conducted prior to the acquisition of the heat transfer data. The influence of the secondary flows on the endwall heat transfer distributions, including the leading edge horseshoe vortex system, is particularly visible at lower turbulence levels and lower Reynolds numbers. However, at higher turbulence levels the influence of secondary flows is less visible but the influence of Reynolds number and turbulence on transition can be discerned.
Leakage and Rotordynamic Performance of a Hole-Pattern Multiphase Pump Seal
Authors: Zhang Min , Childs Dara W.
Published: October 2022

Understanding the leakage and rotordynamic performance of a hole-pattern annular seal is critical to the design of a centrifugal pump regarding vibration characteristics and stability. The growing interest in 2-phase pumping, handling gas components in the oil stream directly, brings more challenges to pump design. This paper studies the leakage and rotordynamic performance of a hole-patten annular seal under bubbly (oil/air) flow conditions. The test seal’s length-to-diameter ratio is 0.75. The rotor surface is smooth, and the seal inner surface is textured (65% of the area is occupied by round holes with a depth of 2.5 mm). The test fluid is comprised of silicone oil and air, and the gas volume fraction GVF at the seal inlet is from zero to 9.3%. Tests also cover two pressure drops (44.8 and 55.1 bars) and three rotor speeds (5, 10, and 15 krpm). Test results showed that adding air to the oil (inlet GVF up to 9.3%) has a small impact on mass flow leakage. Mass flow leakage increases slightly (by ∼4%) as inlet GVF increases from zero to 3.4% and then decreases slightly (by < 5%) as inlet GVF is further increased to 9.3%. As inlet GVF increases, measured values of direct stiffness K, direct damping C, cross-coupled damping c, and direct virtual-mass M decrease. Adding air to the oil (inlet GVF up to 9.3%) shows no obvious impact on measured cross-coupled stiffness k and measured effective damping Ceff. Measurements are also used to examine San Andres’s bulk-flow model (2011, “Rotordynamic Force Coefficients of Bubbly Mixture Annular Pressure Seals,” ASME J. Eng. Gas Turbines Power, 134(2), p. 022503). The model shows limited capability in predicting the performance of the hole-pattern seal under mainly-oil conditions. The discrepancy between the experimental results and theoretical predictions calls for more improvements in the predictive model to handle hole-pattern seals with mainly-oil mixtures.
Reconstructing Turbine Non-Uniform Flow Including Hot Streaks Using Spatially Under-Sampled Measurements
Authors: Zhu Xu , Lou Fangyuan , Zhou Kai , Zheng Xinqian
Published: October 2022

The demand for higher thermal efficiency of gas turbines has been pushing the limit of turbine inlet temperature. Modern high-pressure turbine (HPT) blades are cooled with a combination of film cooling, impingement cooling, and passage cooling. However, for a given material and cooling strategy, the turbine inlet temperatures are limited by the performance penalty caused by the required cooling air typically extracted from the high-pressure compressor. Although it is well recognized that the HPT inflow is highly unsteady and non-uniform, it is still generally the case that turbines are designed for uniform inlet temperature — often the predicted peak gas temperature due to the vacancy of a reliable methodology for estimating the non-uniform temperature field at HPT inlet. This paper introduces a new approach to predicting the turbine inlet temperature, including the magnitude of non-uniformity, based on a few temperature measurements at the HPT exit to shed light on this topic. The technique includes three steps. First, investigate the hot streaks migration across the HPT and establish a projection of hot-streaks-related magnitude from HPT inlet to exit. Second, resolve the hot-streaks-related extent at HPT exit using a multi-wavelet approximation method based on a few discrete measurements. Lastly, estimate the HPT inlet mean temperature and magnitude of hot streaks. The method’s effectiveness is examined using the two-stage high-pressure turbine from Energy Efficiency Engine (E3). An engine representative HPT inlet temperature distribution available in the open literature is applied at the HPT inlet. The true temperature distribution at HPT exit is obtained from full-annulus unsteady simulations. The estimated HPT inlet temperature distribution using the new approach agrees with the true values, with an error of less than 0.3% in the mean temperature and uncertainty on the order of 20% in the magnitude of hot streaks.
Roller Bearing Skidding for Aero-Engine Applications: All-Steel Versus Hybrid Bearings
Authors: Dadouche Azzedine , Kerrouche Rami
Published: October 2022

Roller bearings operating under light loads may suffer from skidding. The latter is more pronounced as the speed increases and may result in extensive wear and reduced service life of the bearing. The main objective of this study is to analyze skidding occurrence in a custom-made all-steel M50 bearing and a hybrid roller bearing subjected to the same operating conditions. The test bearings have a bore diameter of 90 mm, an outer diameter of 125 mm and 26 rollers. The hybrid bearing features silicon nitride (Si3N4) rollers and steel rings (M50 outer ring and M50-NIL inner ring). The bearings feature special channels to allow for under race lubrication of the bearing components in relative motion. A suite of sensors were used and installed to detect skidding and monitor the overall performance of the test bearing such as vibrations and temperature. The effect of the radial applied load, shaft rotational speed and oil flow rate on roller skidding have been investigated and discussed. Slip ratio for each of the bearings under various speed-load combinations was also determined and analyzed. Turbo oil 2380 was used to lubricate the test bearings at a constant temperature of 77°C. Tests were conducted on a high-speed rolling bearing test rig and data was recorded using a 24-bit data acquisition system.
Nonlinear Surrogate Models for Gas Turbine Diagnosis
Authors: Loboda Igor , González Castillo Iván , Yepifanov Sergiy , Zelenskyi Roman
Published: October 2022

In gas turbine diagnostics, a significant contradiction is observed between the variety of methods proposed and a limited number of the algorithms realized in real monitoring systems. One of the explanations is the shortage of simple, but reliable and accurate diagnostic solutions. Many actual solutions are based on a nonlinear thermodynamic model; however, this physics-based model and an iterative procedure to adapt it are complex, critical to computer resources, and does not always converge. On the other hand, the used linear models are simple, but not accurate enough.

The present paper proposes and analyzes two types of nonlinear simplified static data-driven models based on the steady-state data generated by the thermodynamic model. The first type includes direct models that compute monitored variables Y for given operating conditions U and fault parameters δΘ. The second type presents inverse models that estimate parameters δΘ using variables U and Y as inputs. The paper aims to create such models, optimize them, and show that they can be a good surrogate for the original thermodynamic model and its adaption procedure.

Based on the experience of the development of baseline models, we employ polynomials and multilayer perceptron as approximation techniques. Adjustment of the techniques and their comparison allow choosing the best one. To draw solid conclusions on the utility of the proposed models, three different engines are used as test cases. The results of the verification of these models are promising for their use in gas turbine diagnostic and control systems.
A Review of Pressure Gain Combustion Solutions for Aerospace Propulsion
Authors: Purushothaman Sreenath , Renuke Avinash , Sorce Alessandro , Traverso Alberto
Published: October 2022

Recent developments in Pressure Gain Combustion (PGC) technology have demonstrated its ability to achieve higher thermal efficiencies and lower carbon emissions as compared to conventional gas turbine counterpart working in Brayton cycle. Ongoing studies suggest the possibility of implementing PGC in aircraft engines by replacing the high-pressure section (HP compressor, combustion chamber and HP turbine) with a PGC system. This, coupled with research on advanced materials and cooling solutions, offers the potential for higher overall gas turbine efficiency and fuel economy, contributing towards emission reduction of the aviation sector.

This paper aims at a comprehensive review of PGC technology solutions applied in the area of aero propulsion. Reported background covers the historic as well as ongoing research activities at the component level, the cycle level, and the propulsion application of Pulse Detonation Engine (PDE), Rotating Detonation Engine (RDE), Oblique Detonation Wave Engine (ODWE), Free Piston Composite Cycle Engine (FP-CCE), and wave rotor engines. The analytical, numerical, and experimental research work is reviewed, providing also a comparison of PGC engine conceptual designs with existing gas turbine engines used in aerospace propulsion.
Numerical Investigation of Laidback Fan-Shaped Film Cooling Holes With Large Eddy Simulation
Authors: Yang Lianfeng , Satta Francesca , Barsi Dario , Zunino Pietro , Luan Yigang
Published: October 2022

Due to the high demand for the output power and thermal efficiency, the turbine inlet temperature is extremely high which has significantly exceeded the melting point of the blade material. Therefore, the turbine blade cooling system plays a pivotal role in the entire engine. As for the external cooling, film cooling technology has been widely used in the modern advanced design of gas turbines in order to enhance the cooling performance and reducing the cooling air usage. According to the public literature, conventional cylindrical film cooling hole has been studied by many researchers, whereas the laidback fan-shaped film cooling hole, as a cutting-edge technology, is relative novel, advantageous and still under investigation. Thus, large eddy simulation (LES) method was implemented to study the flow field and the thermal performance of shaped film holes at turbulence intensity Tu = 0.5%, density ratio DR = 1.5, blowing ratio M = 0.5–3.0 and momentum flux ratio I = 0.17–6.00. The adiabatic film cooling effectiveness with LES shows a good agreement with the experimental data. A comparison was conducted between the conventional cylindrical film hole and the laidback fan-shaped film hole in the range of M = 0.5–1.5. The results show that shaped film hole obtains better cooling effectiveness with sufficient spread in spanwise direction as the blowing ratio increases, and M = 1.5 can provide a relative better performance for shaped film hole. As for the details of the flow field, the counter-rotating vortex pair (CRVP) and anti-CRVP structures are found in the simulation. Time-averaged Reynolds shear stresses and turbulence viscosity exhibit strong anisotropic properties near the bottom surface. The analyses may help to understand the characteristics of the laidback fan-shaped film cooling and guide the cooling design of the turbine blade.
Predicting Cavitation Erosion on Two-Stage Pumps Using CFD
Authors: Verhulst Tedja , Ng Eddie Yin-Kwee , Chung Yongmann , Judt David , Lawson Craig
Published: October 2022

Cavitation is a common problem that occurs in pumps which reduces its useful life and bring increased operating costs to the user. A study of cavitation erosion on a two-stage centrifugal pump has been carried out using Computational Fluid Dynamics (CFD). Most cavitation studies on pumps have been focused on modelling the severity of cavitation; specifically, on understanding its visual effects and performance penalties. Few works have been carried out to predict the most erosion-sensitive areas inside a pump. The focus of this study is on modelling the permanent damage that would be caused by cavitation and to identify specific areas within the pump which are most susceptible to erosion. The model is first validated against experimental data from another work. Once the simulation has been successfully calibrated, the cavitation simulation is carried out again with the subject pump. Not only does this work extend the findings previous works by predicting cavitation erosion on a two-stage pump, but the pump rotation speed is also varied to observe how the erosion-sensitive areas on the pump changes as a result. A specific focus on the Gray Level Method is carried out to predict the erosion damage on the pump. This technique is chosen as it has been experimentally proven with single-stage radial pumps, using specialized CFD code. It is found that the algorithm used to predict erosion when applied with commercial CFD packages, are useful in distinguishing areas inside the pump which are most vulnerable to erosion damage. The Scherr-Sauer cavitation model coupled with the κ-ω SST turbulence model have been used to run the cavitation simulations.
Experimental Investigation of Heat Transfer in a Rotating Lateral Outflow Trapezoidal Channel With Pin-Fins
Authors: Zhang Xuejiao , Li Haiwang , You Ruquan , Liu Song , Tao Zhi
Published: October 2022

In this study, the heat transfer characteristics in a rotating lateral outflow trapezoidal channel with pin-fins, which is a typical model of the internal cooling passage in a turbine blade, were experimentally investigated under the Reynolds number range of 10,000–80,000, rotating speed range of 0–1000 rpm. The tested Re and Ro ranges are considerably extended from the previous experiences. For the non-rotating condition, the heat transfer characteristics of the leading and trailing sides of the internal channel are relatively uniform due to the different construction. On the inner smooth surface, at Re = 30000 of non-rotating, the leading and trailing averaged Nusselt number of the point near the inlet is about 48% higher than that at the end of the channel, but on the outer pin-fin arrayed surface, the averaged Nusselt number decreases about 20.5%. For the rotating conditions, the heat transfer of inner leading surface significantly reduced due to the rotation-induced Coriolis force and coolant discharged from the channel along the outlets. Interestingly, with Reynolds number increases, the Nusselt number ratios decreases. When the rotating speed is 1000 rpm and the Reynolds number is 10000, 3000, 50000 and 70000, the Nusselt number ratios are 2.11, 1.40, 1.19 and 1.07 respectively. Moreover, the leading side of the inner smooth area exhibit a critical rotation number, in which the rotation weakened the heat transfer before the critical point and promoted heat transfer after the critical point. However, the critical rotation number varied with X/D.
Centrifugal Compressor Retrofit: Geometry Rebuild and 3-D Blade Shape Optimization
Authors: Kienzle Norman , Hoang Duc Huy Marco , Martis Warren John , Moch Markus , Doetsch Christian , di Mare Francesca
Published: October 2022

This article summarizes the development of an aerodynamic retrofit for a centrifugal compressor stage. In the first part, a method to replicate the open design case ‘Radiver’ (RWTH Aachen University), using an in-house tool (NarTIG) is presented. The geometry is then used as a starting point for a 3D aerodynamic full stage blade shape optimization. The results of the optimization are shown in the second part of the paper. The results of the fully 3D-optimized profiles of the impeller blades and diffuser vanes show a significant reduction of spanwise leading edge loading, leading to an increase of 2-percentage points in total-static polytropic efficiency at optimal conditions. An increase of 20-percentage point with respect to high flow conditions is also reached.
A Machine Learning Approach for Stress-Rupture Prediction of High Temperature Austenitic Stainless Steels
Authors: Hossain Md Abir , Mireles Adan J. , Stewart Calvin M.
Published: October 2022

This study outlines a machine learning approach for long-term stress-rupture (SR) prediction of high temperature austenitic stainless steel. Traditional methods of lifetime estimation and alloy design for turbomachinery application rely mostly on repeated testing, prior experience, and trial-and-error approach, which are laborious, time intensive, and costly. Recent advances in machine learning offer an accelerated technique for the development of constitutive creep laws, superior alloy designs, and reliable long-term performance prediction. To that end, a machine learning approach is explored in this study for long-term stress-rupture prediction. The toolbox GPTIPS, a biologically inspired genetic programming (GP) algorithm for building accurate and intrinsically explainable non-linear regression model is employed in this study. In GPTIPS, randomly sampled tree structures, mutate and cross over the best performing trees to create a new sample. The process iterates until the best solution is found based on criteria set by the user. Herein, the stress-rupture data of 18Cr-8Ni (304 SS) stainless steel, divided into 60% training and 40% testing data irrespective of heat grades are feed into GPTIPS. The GPTIPS is iterated based on the number of genes, tournament size, tree depth, and nodes. The generated SR constitutive models are ranked according to goodness-of-fit and model complexity. The best-ranked models are compared with the experimental data and found to be free of inflection points at low-stress. Post audit validation is performed by fitting the model blindly against an extended data base of 18Cr-12Ni-Mo (316 SS) stainless steel. Based on the goodness-of-fit, the best-ranked models are investigated for future application, comprehensive understanding of their limitations, and the resultant capability of effective prediction. In future work, the ability of GPTIPS will be leveraged to develop minimum-creep-strain-rate models, alloy design based on chemical composition, potential sources of uncertainty, and their implications on the outcomes.
New records of mites from some European countries (Trombidiformes: Erythraeidae, Trombidiidae) with new data for some species
Authors: Haitlinger Ryszard
Published: October 2022

Abrolophus wratislaviensis, Charletonia cardinalis and Erythraeus (Zaracarus) budapestensis are recorded for the fisrst time from France, C. postojnensis from continental Italy and Serbia, Balaustium nikae and B. ryszardi from Sicily, B. nikae from Spain and B. murorum from Ukraine. New or corrected metric data for C. cardinalis C. postojnensis, B, murorum, B. nikae and B. ryszardi are provided. A list of Parasitengona mites for France, Serbia, Sicily and Ukraine is given. The relations between species of the genus Abrolophus and the Balaustiinae subfamily with their hosts are discussed.
Iranotrichus crassisetosus gen. nov., sp. nov. (Acari: Oribatida: Zetomotrichidae) from central Iran
Authors: Akrami Mohammad Ali , Coetzee Louise
Published: October 2022

A new genus and species of oribatid mites (Oribatida) of the family Zetomotrichidae are described from soil in the Central Plateau of Iran, Yazd Province. Iranotrichus gen. nov., with type species Iranotrichus crassisetosus sp. nov., differs from all other genera of the family by a combination of the following character states: large body size; denticulate rostrum; dorsosejugal furrow medially interrupted; divided posterior margin of notogaster; prodorsal, notogastral and ventral plates ornamented with fine, fragmented longitudinal striae; large, thick notogastral seta c2; presence of notogastral lyrifissures ia and im, humeral sac and pyriform organ; absence of custodium; barbed epimeral setae, 1a and 1c longer than others, 1a longest; four pairs of genital, two pairs of anal and three pairs of adanal setae; tarsus I with 20 setae; presence of thick setae on genua I and II, tibia II and tarsi II–IV, with seta tc″ on tarsus IV slightly enlarged but not a thick spine; leg IV enlarged, acetabulum not dorsally displaced. Leg IV representing an intermediate stage between the genera with a well-developed jumping leg and those without a jumping leg. In addition, data on geographic distribution and some information about all known genera of Zetomotrichidae are given.
Supra-threshold deficits in normal hearing military recruits exposed to impulse noise
Authors: Pinsonnault-Skvarenina Alexis , Soucy William , Noël Jonathan , Doucet Félicia , Lévesque Élise , Fuente Adrian , Leroux Tony
Published: October 2022

The aim of this study was to determine the effect of impulse noise exposure on various proxy measures of cochlear synaptopathy in young military recruits. A total of 27 military recruits with exposure to firearm and artillery noise and 13 non exposed participants were recruited. All presented with normal hearing thresholds and the presence of distortion product otoacoustic emissions (DPOAEs). The Noise Exposure Structured Interview (NESI) was used to quantify noise exposure. Speech perception in noise (SPiN), equivalent rectangular bandwidth (ERB) of auditory filters, auditory brainstem response wave I amplitude, wave I amplitude growth function, wave I/V amplitude ratio, wave V latency, wave V latency shift with ipsilateral noise, and the summating potential/action potential ratio of the electrocochleography were measured. In military participants, SPiN was worse, ERB at 4 kHz was larger, wave I amplitude at 75 dBnHL was reduced, and wave V latency was delayed. However, no significant correlations were observed between NESI and auditory measures, once multiplicity of tests was controlled for. These results suggest that military recruits may exhibit supra-threshold deficits, despite presenting with normal hearing thresholds and presence of DPOAEs. Future studies should include a measure of auditory filters in their test battery.
Visual attention does not affect the reliability of otoacoustic emission or medial olivocochlear reflex
Authors: Jedrzejczak W. Wiktor , Milner Rafal , Pilka Edyta , Ganc Malgorzata , Skarzynski Henryk
Published: October 2022

This study investigated whether visual attention affects the reliability (i.e., repeatability) of transiently evoked otoacoustic emission (TEOAE) magnitudes or of medial olivocochlear reflex (MOCR) estimates. TEOAEs were measured during three visual attentional conditions: control (subject were seated with eyes closed); passive (subjects looked at a pattern of squares on a computer screen); and active (subjects silently counted an occasionally inverted pattern). To estimate reliability, the whole recording session was repeated the next day. The results showed that visual attention does not significantly affect TEOAE or MOCR magnitudes—or their reliability. It is therefore possible to employ visual stimuli (e.g., watching a silent movie) during TEOAE experiments, a procedure sometimes used during testing to prevent subjects from falling asleep or to keep children still and quiet.
Focal depth localization for highly focused transducers in isotropic materials
Authors: Katch Lauren , Argüelles Andrea P.
Published: October 2022

Focusing equations aim to define the point in a solid at which a transducer beam will reach a minimum cross section. The most commonly used focusing equation relies on a small angle assumption that inherently excludes sharply focused transducers with significant curvature. In this article, a revised focusing equation is proposed for normal and oblique incidence through a fluid-solid interface. The closed-form equation is derived using ray tracing approaches similar to the conventional expression but circumvents the paraxial approximation, extending the applicability to sharply focused probes. Both conventional and modified focusing equations are compared through normal and oblique incidence ray diagrams, and the proximity to the computationally derived geometric focus is explored. The proposed modification to the focusing equation generally results in a closer approximation to the geometric focus, a smaller beam cross section, and a greater time convergence when compared to the conventional focusing equation.
Metabolic synergy in Camelina reproductive tissues for seed development
Authors: Koley Somnath , Chu Kevin L. , Mukherjee Thiya , Morley Stewart A. , Klebanovych Anastasiya , Czymmek Kirk J. , Allen Doug K.
Published: October 2022

Photosynthesis in fruits is well documented, but its contribution to seed development and yield remains largely unquantified. In oilseeds, the pods are green and elevated with direct access to sunlight. With
13
C labeling in planta and through an intact pod labeling system, a unique multi-tissue comprehensive flux model mechanistically described how pods assimilate up to one-half (33 to 45%) of seed carbon by proximal photosynthesis in
Camelina sativa
. By capturing integrated tissue metabolism, the studies reveal the contribution of plant architecture beyond leaves, to enable seed filling and maximize the number of viable seeds. The latent capacity of the pod wall in the absence of leaves contributes approximately 79% of seed biomass, supporting greater seed sink capacity and higher theoretical yields that suggest an opportunity for crop productivity gains.
Inhibition mechanism of NKCC1 involves the carboxyl terminus and long-range conformational coupling
Authors: Moseng Mitchell A. , Su Chih-Chia , Rios Kerri , Cui Meng , Lyu Meinan , Glaza Przemyslaw , Klenotic Philip A. , Delpire Eric , Yu Edward W.
Published: October 2022

The Na-K-2Cl cotransporter-1 (NKCC1) is an electroneutral Na
+
-dependent transporter responsible for simultaneously translocating Na
+
, K
+
, and Cl
−
ions into cells. In human tissue, NKCC1 plays a critical role in regulating cytoplasmic volume, fluid intake, chloride homeostasis, and cell polarity. Here, we report four structures of human NKCC1 (hNKCC1), both in the absence and presence of loop diuretic (bumetanide or furosemide), using single-particle cryo–electron microscopy. These structures allow us to directly observe various novel conformations of the hNKCC1 dimer. They also reveal two drug-binding sites located at the transmembrane and cytosolic carboxyl-terminal domains, respectively. Together, our findings enable us to delineate an inhibition mechanism that involves a coupled movement between the cytosolic and transmembrane domains of hNKCC1.
Peptide-DNA origami as a cryoprotectant for cell preservation
Authors: Lee Chanseok , Lee Yedam , Jung Woo Hyuk , Kim Tae-Yeon , Kim Taehwi , Kim Do-Nyun , Ahn Dong June
Published: October 2022

Cryopreservation of cells is essential for the conservation and cold chain of bioproducts and cell-based medicines. Here, we demonstrate that self-assembled DNA origami nanostructures have a substantial ability to protect cells undergoing freeze-thaw cycles; thereby, they can be used as cryoprotectant agents, because their nanoscale morphology and ice-philicity are tailored. In particular, a single-layered DNA origami nanopatch functionalized with antifreezing threonine peptides enabled the viability of HSC-3 cells to reach 56% after 1 month of cryopreservation, surpassing dimethyl sulfoxide, which produced 38% viability. It also exhibited minimal dependence on the cryopreservation period and freezing conditions. We attribute this outcome to the fact that the peptide-functionalized DNA nanopatches exert multisite actions for the retardation of ice growth in both intra- and extracellular regions and the protection of cell membranes during cryopreservation. This discovery is expected to deepen our fundamental understanding of cell survival under freezing environment and affect current cryopreservation technologies.
Diversity dependence is a ubiquitous phenomenon across Phanerozoic oceans
Authors: Rineau Valentin , Smyčka Jan , Storch David
Published: October 2022

Biodiversity on Earth is shaped by abiotic perturbations and rapid diversifications. At the same time, there are arguments that biodiversity is bounded and regulated via biotic interactions. Evaluating the role and relative strength of diversity regulation is crucial for interpreting the ongoing biodiversity changes. We have analyzed Phanerozoic fossil record using public databases and new approaches for identifying the causal dependence of origination and extinction rates on environmental variables and standing diversity. While the effect of environmental factors on origination and extinction rates is variable and taxon specific, the diversity dependence of the rates is almost universal across the studied taxa. Origination rates are dependent on instantaneous diversity levels, while extinction rates reveal delayed diversity dependence. Although precise mechanisms of diversity dependence may be complex and difficult to recover, global regulation of diversity via negative diversity dependence of lineage diversification seems to be a common feature of the biosphere, with profound consequences for understanding current biodiversity crisis.
Optimization of the parameters impacting the Direct Red 89 degradation with thermally activated persulfate using a full factorial design
Authors: Nadji Nawel , Bouarra Nabil , Nouri Loubna , Djebli Abdelkrim , Boudjemaa Amel , Nouri Nabila , Hemidouche Sabra , Djerad Souad , Bachari Khaldoun
Published: October 2022

A two-level full factorial design with interactions was effectively used to screen for parameters impacting the degradation of Direct Red 89 (DR89) by thermally activated persulfate. Four variables were identified as critical: reaction temperature, persulfate concentration, initial pH of medium, and initial DR89 concentration. The goodness of fit of the reduced model was tested by generating plots of descriptive statistic, residuals versus predicted responses, normal probability versus residuals, and observed versus predicted values, as well as examining the analysis of variance table. The observed and the predicted response values of the reduced model exhibited a good correlation, with R2, [Formula: see text] , Q2, and p of 0.990, 0.983, 0.968, and 0.000, respectively. To determine optimal operating parameters, the desirability function was utilized, and it was determined to be 0.988 with a predicted response of 99.89% for an initial DR89 concentration of 51.96 mg/L, a persulfate concentration of 12 mmol/L, a reaction temperature of 60 °C, and a pH of 3.
Synchronization of cooperative and competitive oscillators in dynamical network
Authors: Ling Xiang , Hua Bo , Jing Xing-Li , Guo Ning , Li Ling-Lin , Zhu Kong-Jin , Chen Jia-Jia
Published: October 2022

Synchronization is a collective behavior that occurs spontaneously, describing the coherence of a collection of dynamic units of a system. The competitive and cooperative behavior of the synchronization process as the simplest synergistic behaviors can promote or inhibit each other, which has been widely investigated for its practical significance in recent years. Here, we report that the synchronization phase transition type can be tuned by adjusting the balance between the two oscillator types and the communication radius of the dynamical network in a population dynamical network with uniformly distributed competitive and cooperative oscillators. Agents of both cooperative and competitive oscillators move and interact only with their neighbors in a system. By numerical simulations, we demonstrate a rich process of synchronous transitions, especially that the transition can be regulated between continuous and explosive by adjusting the balance between the two oscillator types under a specific dynamic network. Moreover, the communication radius of the network and the number of oscillators determine both the density of oscillators in the system, thus changing the connectivity and the synchronization characteristics of the network.
First-principles study of 6-Amino crystal under high pressure
Authors: Zhang Chao , Chen Limin , Luo Jianbing , Liu Chunsheng , Xie Qiyun , Wei Chao , Gong Zhicheng
Published: October 2022

In this paper, density functional theory (DFT) is used to study the structure, electron and absorption properties of 6-Amino crystal in the pressure range of 0–300[Formula: see text]GPa. The variations of the lattice constants, bond lengths and bond angles show that they undergo complex transformations under different pressures. More narrowly, the covalent bonds of the benzene ring and the uracil ring in the planar intramolecular structure are broken, and then the new covalent bonds between the adjacent intermolecular structure are reshaped at about 80, 100 and 160[Formula: see text]GPa. The analysis results of band gap and DOS of 6-Amino indicate that the electronic properties of 6-Amino repeatedly transform from the semiconductor system into the metal phase at 80, 180 and 260[Formula: see text]GPa. The absorption spectra show two important structural changes at 100 and 180[Formula: see text]GPa, and present the high optical activity with the change of pressure.
Gravitational field effects produced by topologically nontrivial rotating space–time under magnetic and quantum flux fields on quantum oscillator
Authors: Ahmed Faizuddin
Published: October 2022

In this paper, we study the gravitational field effects produced by a topologically nontrivial four-dimensional geometry on a relativistic quantum oscillator in the presence of a uniform magnetic field and quantum flux. We introduced the noninertial effects of a rotating frame of reference and solved analytically the generalized KG-oscillator for Coulomb- and Cornell-type potential functions using the Nikiforov–Uvarov method. We discuss the effects of the rotating frame, the nontrivial topology and the external magnetic field on the eigenvalue solutions of the oscillator fields.
Characterization of two-dimensional cellular elastic topological insulators based on regular-hexagon carriers
Authors: He Guangchen , Qin Yao , Wang Qifu , Cai Chengxin
Published: October 2022

An elastic topological insulator with pseudo-spin characteristics is designed based on honeycomb lattice phononic crystals with positive hexagonal carriers, which can realize path defect immunity and backscattering suppression transmission characteristics. By introducing a positive hexagon carrier with a certain size at the narrow diameter junction of the two-dimensional honeycomb structure to achieve symmetry breaking, a four-fold accidental degeneracy point can be obtained by adjusting the cell parameters. The main variable of the primitive cell is the hexagonal carrier side length [Formula: see text]. It is found that the four-fold Dirac point can be opened and a band gap can be formed by contracting the positive hexagonal carrier. Inversion of the energy band occurred in the separated two-fold degenerate state, for which the transformation of mediocre state and nonmediocre state had been realized so that the structure with acoustic pseudo-spin and topological edge state could be obtained. Based on the principle of body-edge state correspondence, the topologically protected edge acoustic transmission is simulated by the construction of the edge states combined with the connection of different structural systems. Further, different elastic phonon crystal structures are constructed, and the characteristics of path defect immunity and back-scattering suppression of elastic wave propagation by topological edge states are verified. The designed elastic topological insulators have great application prospects in the regulation of elastic waves.
Optical absorption of tri-doped (Mo, Y, N)-TiO2 with first-principle calculations
Authors: Khan Hamid , Iqbal Yaseen , Khan Matiullah , Zeng Yi
Published: October 2022

In this theoretical study, a path was adapted to investigate the redshifting of the TiO2 absorption edge by molybdenum (Mo), yttrium (Y) and nitrogen (N) doping. The geometrical model, band gap and photo response were noted in the developed model of anatase TiO2. The tri-doped model showed very small modification in the structure as compared to a reference TiO2 model. The 3d states of Mo mix up with the 3d states of Ti, resulting in the reduction of band gap. The Y 2p states were introduced around the middle of the band gap of Y-doped TiO2. Good reduction was found in the gap of tri-doped TiO2 model and the created states were occupied. The doping of N via oxygen (O) substitution in tri-doped model resulted in the band gap reduction by introducing states in the band gap due to the mixing of N 2p and O 2p states.