Loss Characteristics Research Articles

The Prevalence and Clinical Characteristics of MYO3A-Associated Hearing Loss in 15,684 Hearing Loss Patients

Background/Objectives: MYO3A belongs to the unconventional myosin superfamily, and the myosin IIIa protein localizes on the tip of the stereocilia of vestibular and cochlear hair cells. Deficiencies in MYO3A have been reported to cause the deformation of hair cells into abnormally long stereocilia with an increase in spacing. MYO3A is a rare causative gene of autosomal recessive sensorineural hearing loss (DFNB30), with only 13 cases reported to date. In this study, we aimed to elucidate the phenotypes caused by MYO3A variations. Methods: Massively parallel DNA sequencing was performed on 15,684 Japanese hearing loss patients (mean age 27.5 ± 23.1 years old, 6574 male, 8612 female and 498 patients for whom information was unavailable), identifying nine candidate patients with MYO3A variants. Results: We identified eight causative MYO3A variants by massively parallel DNA sequencing, including six novel variants, and reported nine individuals possessing MYO3A gene variants, which is the largest group of non-related patients yet to be detected. Our findings confirmed that MYO3A variants cause progressive hearing loss, with its onset varying from birth to the second decade, eventually leading to severe-to-profound hearing loss. Conclusions: We clarified that patients with MYO3A gene variants present with late-onset, progressive hearing loss. Our findings have enabled us to predict the outcomes of hearing loss in patients with candidate MYO3A gene variants and to provide intervention in a timely manner.

The role of audiological features and horizontal semicircular canal function at various frequencies in vestibular migraine and Menière’s disease

Background Vestibular migraine (VM) and Menière’s disease (MD) have numerous overlapping symptoms. Distinguishing the two common recurrent vestibulopathies was challenging. Objectives To assess the characteristics of hearing loss and the horizontal semicircular canal function in VM and MD. Materials and methods Various frequency horizontal semicircular canal function tests, including caloric test, video head impulse test (vHIT), and rotatory chair test, as well as multifrequency audiological test with pure-tone average (PTA), were carried out. Results The hearing threshold of all frequencies in VM is lower than that of MD (p < .05). The phase shift at 0.01 Hz, 0.02 Hz, 0.04 Hz, 0.08 Hz and 0.64 Hz was significantly different in VM and MD patients. The gain at 0.01 Hz differed between VM and MD (p < .05); the time constant (RTc) in VM patients was longer than that of MD patients (p < .05). The incidence of caloric test abnormality was 40% in VM patients and 68.3% in MD patients. The abnormal rate of horizontal semicircular canal vHIT was 3.2% in VM and 5.8% in the MD, and the rates of overt/cover saccades were 9.7% and 17.6%, respectively. Conclusions The degree and type of hearing loss were conducive to distinguishing between VM and MD, and the rotatory chair test was a necessary supplement.

Effects of relative phase position of blades on the cascade performance of highly loaded helium compressor

The operational environment of highly loaded helium compressor necessitates characteristics with narrow flow passages and short blade heights. These characteristics result in more prominent blade tip clearance leakage issues and stronger wake effects compared to air compressors. This study aims to clarify the separation flow structure and the spatiotemporal evolution mechanism of the highly loaded helium compressor cascade and to provide technical support for the aerodynamic stability optimization of such compressors. The present study investigated the effect of the relative positions of the upstream blade wake and downstream blade on cascade loss and separation characteristics of the highly loaded helium compressor with numerical and experimental analysis. The results demonstrate that the proportion of secondary flow losses, including tip leakage vortex of the downstream blade, is the lowest when the circumferential distance between the upstream inlet guide vane wake and the downstream rotor leading edge is 0.5 pitch, with an overall loss weight of 10.8% at the outlet section. Moreover, the proportion of secondary flow losses, including tip leakage vortex of the downstream rotor, is the highest when the circumferential distance between the upstream guide vane wake and downstream rotor leading edge (suction surface side) is 0.25 pitch. The overall loss weight at the outlet section for this position is 21.7%, which is twice that when the circumferential distance is 0.5 pitch. In addition, it can be demonstrated that tip leakage vortex plays a dominant role in vortex losses across all relative positions of the blades.

Model test study on the rainfall erosion mechanisms and reclamation potential of open-pit coal mine dump soil improved by fly ash and polyacrylamide

Increasing the soil erosion resistance is one of the core issues in slope erosion control and ecological environmental restoration of open-pit coal mine (OPCM) dumps. In this study, fly ash (FA) and polyacrylamide (PAM) were used to improve the soil quality of an OPCM dump, and an indoor physical model was constructed to investigate the water and soil loss characteristics of the improved soil via simulated rainfall experiments. Scanning electron microscopy and Pore and Crack Analysis System software were employed to systematically investigate the erosion resistance mechanisms of the improved soil qualitatively and quantitatively. Finally, the improved technique for order preference by similarity to an ideal solution (TOPSIS) method was adopted to evaluate the reclamation potential of the improved soil. The results revealed that under the action of PAM (PAM and PAM–FA), the average erosion rate of the slope decreased by more than 90 %. Compared with that in the control group, when FA was applied alone, the slope erosion rate first decreased and then increased with increasing FA content. Upon PAM addition, the erosion pattern changed from the splash erosion stage, cave erosion stage, gully erosion stage, and tensile slip stage to the splash erosion stage and cave erosion stage. However, no obvious change in the runoff pattern. Erosion and runoff patterns are generally affected by the amendment type, addition concentration, porosity, pore shape, pore direction and hydrological environment. The erosion resistance mechanism of the improved soil entailed the formation of more stable soil aggregates via filling, cementation, skeleton support generation, and flocculation of FA and PAM. In addition, the optimal soil improvement was achieved when FA and PAM were added at levels of 16 % and 0.01 %, respectively. The obtained research results could be used for erosion control and ecological environmental protection of coarse-grained soil slopes in mining areas, highways and other fields and could be widely applied.

Interlayer air-hole photonic crystal fiber with flat dispersion and three zero dispersion wavelengths for supercontinuum generation

This paper proposes an Interlayer Air-hole Photonic Crystal Fiber (IA-PCF) consisting of five air-hole layers with a single material, which means compatibility checking between the core and cladding material need not be required. The optical fiber is designed using COMSOL software. Further more, the dispersion, nonlinearity, effective mode area, and confinement loss characteristics of the proposed IA-PCF structure are numerically analyzed using the finite element method (FEM). The results indicate that the proposed IA-PCF has three zero dispersion wavelengths (ZDW) within 800–2400 nm. Through continuous structural optimization, a flat dispersion optimal IA-PCF with a dispersion fluctuation of ± 2.05 (ps/nm·km) in the range of 1509 nm-1955 nm is obtained. The three zero dispersion wavelengths (ZDW) of the optimal IA-PCF are 1061 nm, 1598 nm, and 1904 nm, respectively. Four input 50 fs pulses both in the normal and anomalous dispersion regimes are explored to analyze the spectral evolution process of SC in a 30 cm lenth IA-PCF. The results indicate that the continuous SC exists in the range of 750 nm-2430 nm at the pump wavelength of 1064 nm with power range of −40 dB. While the continuous broadband SC exists in the range of 1235 nm-3470 nm at the pump wavelength of 1550 nm with power range of −43 dB. In addition, a broadband, flat SC spectrum with a power range of −26.8 dB to −18.6 dB is obtained in the wavelength range of 1331 nm-2315 nm at a pump wavelength of 1080 nm. The IA-PCF provides a new structure and approach for generating a broadband, flat and SC spectrum. The supercontinuum belongs to a wide range of applications in optical communication, optical coherence tomography, optical frequency comb etc.

AC Loss Characteristics of High-Temperature Superconducting Tapes under over-Current Conditions

AC Loss Characteristics of High-Temperature Superconducting Tapes under over-Current Conditions

The Spatio‐Temporal Characteristics of Flow Field Inside a Self‐Priming Pump During the Self‐Priming Process

ABSTRACTIn this article, a closed‐loop piping system that includes the self‐priming pump is established and calculated. Two operating processes reflecting real situations are accurately calculated by means of UDF. The vortex identification method, entropy production theory, and energy gradient method are employed to deeply analyze and reveal the energy loss characteristics and flow stability. The results show that in the oscillating exhaust stage, the energy loss is greatest during the oscillating exhaust stage of the self‐priming process. The reflux hole, the tongue, and the outlet section of the volute have larger energy loss. Within the impeller region, the entropy production is mainly concentrated at the impeller inlet and outlet; the entropy production distribution area and value are larger in the clearance of the wear‐ring. In addition, the instability region in the impeller and the left side of the volute is significantly larger than the rest of the locations and increases considerably with the self‐priming process.

Embedded Rough-Neck Helmholtz Resonator Low-Frequency Acoustic Attenuator

In various practical noise control scenarios, such as duct noise mitigation, industrial machinery, architectural acoustics, and underwater applications, it is essential to develop noise absorbers that deliver effective low-frequency attenuation while maintaining compact dimensions. To achieve low-frequency absorption within a limited spatial volume, this study proposes an embedded Helmholtz resonator featuring a roughened neck and establishes a numerical computational model that incorporates thermos viscous effects. A quantitative investigation is conducted on three types of embedded rough-neck geometries (rectangular-grooved, triangular-grooved, and undulated) to elucidate their acoustic performance, with particular attention to differences in acoustic transmission loss and acoustic impedance characteristics. In response to the practical demand for even lower-frequency attenuation, this work further focuses on optimizing the structural parameters of an embedded rectangular-grooved Helmholtz resonator (ERHR). A back-propagation (BP) neural network models and predicts how structural parameters impact the acoustic transmission coefficient, elucidating the effects of geometric variations. Moreover, by coupling the BP network with the Golden Jackal Optimization (GJO) algorithm, a BP-GJO optimization model is developed to refine the structural parameters. The findings reveal that the proposed method significantly improves resonator spatial utilization at a specific noise frequency while preserving acoustic transmission loss performance. This work thereby provides a promising strategy for designing low-frequency, compact Helmholtz resonators suitable for a wide range of noise control applications.

Research on Performance Prediction of Air Quality Assurance Systems for Gas Turbines Based on Novel Test Method

The quality of air intake significantly impacts the overall performance of gas turbines. A new high-precision testing method for the air intake quality assurance system of gas turbines has been proposed, and the influence of typical intake conditions on the system was studied through this testing method. The research results indicate a positive correlation between filtration efficiency and particle size. Atmospheric temperature, particle concentration, filter differential pressure, and atmospheric humidity all affect filtration efficiency, with their influence decreasing in that order. Additionally, this paper presents a performance prediction model based on the LSTM neural network. The calculation results show that the errors of the filter pressure loss and filtration efficiency model test set are both less than 3%, reflecting the characteristics of pressure loss and efficiency well. The research results have significant engineering application value and provide experimental basis for establishing technical standards and high-precision detection systems for air quality assurance in gas turbines.

Comparative analysis of the hemostatic effect of systemic recombinant Factor VIIa and exogenous fibrin monomer in an experimental model of heparinization and posttraumatic blood loss

This article presents the results of a study of the systemic hemostatic action of recombinant Factor VIIa in a rabbit model of heparin-induced coagulopathy and posttraumatic bleeding, compared to the administration of exogenous fibrin monomer. The coagulopathy was induced by a single intravenous injection of unfractionated heparin at a dose of 150 IU/kg 15 minutes before injury. Recombinant Factor VIIa (270 μg/kg) or fibrin monomer (0.25 mg/kg) was used as systemic hemostatic agents. One hour after administrating the agents, a standardized liver injury was inflicted, followed by an assessment of blood loss characteristics. Using rotational thromboelastometry and coagulation tests, animal venous blood was analyzed for coagulation time, alpha angle, clot formation time, maximum clot firmness, clot density at 10 minutes, activated partial thromboplastin time, prothrombin time, thrombin time, and fibrinogen concentration. Pharmacologically induced coagulopathy resulted in shifts to a hypocoagulable profile, associated with severe blood loss (1.9 times, p = 0.028) and high animal mortality (26.1%, p = 0.022) compared to the control group. Preventive administration of fibrin monomer or recombinant Factor VIIa reduced posttraumatic blood loss (by 5.4 times, p 0.001, and by 2.1 times, p = 0.009, respectively), resulting in a decrease in mortality rates. However, the administration of these agents did not correct the hypocoagulable profile as observed in thromboelastometry and coagulation tests. These data demonstrate the hemostatic effect of both agents, with a more pronounced effect after fibrin monomer administration, and suggest potential use of low doses of fibrin monomer in trauma-related hemorrhage. The mechanism of action of fibrin monomer requires further investigation. Therefore, fibrin monomer, a fibrinogen derivative obtained from blood plasma, could be a valuable candidate for managing wound bleeding in addition to recommended systemic hemostatics.

Local Charge Regulation in Selenides via High‐Entropy Engineering to Boost Electromagnetic Wave Absorption

AbstractLocal charge modulation is an effective method to improve the polarization loss and electromagnetic (EM) absorption characteristics. However, the use of conventional means (doping, defects, heterojunction surfaces) remains singular and limited in achieving local charge modulation. Surprisingly, lattice distortions induced by high‐entropy engineering can intrinsically regulate local charge states and improve EM wave absorption performances. Herein, a series of selenides with enhanced configuration entropy are designed and prepared to improve polarization loss capacity. Due to the different radii of the mixed ions and the Jahn‐Teller distortion effect, the local charge of the selenides is effectively modulated by the presence of defects and strong lattice distortions inside the lattice. Uneven distribution of charge at defects and formation of boundaries promotes defect‐induced polarization and interface polarization, respectively. Compared to single NiSe2, high‐entropy (NiFeCuCoMn)Se2 with an entropy value of 1.53R has more severe lattice defects and suitable impedance matching properties, exhibiting good EM absorption properties both in the absorption intensity and respond frequency. Tailoring the local charge density via an entropy strategy paves a new way for the high‐performance EM absorption materials.

Uncovering the Top Nonadvertising Weight Loss Websites on Google: A Data-Mining Approach.

Online weight loss information is commonly sought by internet users, and it may impact their health decisions and behaviors. Previous studies examined a limited number of Google search queries and relied on manual approaches to retrieve online weight loss websites. This study aimed to identify and describe the characteristics of the top weight loss websites on Google. This study gathered 432 Google search queries collected from Google autocomplete suggestions, "People Also Ask" featured questions, and Google Trends data. A data-mining software tool was developed to retrieve the search results automatically, setting English and the United States as the default criteria for language and location, respectively. Domain classification and evaluation technologies were used to categorize the websites according to their content and determine their risk of cyberattack. In addition, the top 5 most frequent websites in nonadvertising (ie, nonsponsored) search results were inspected for quality. The results revealed that the top 5 nonadvertising websites were healthline.com, webmd.com, verywellfit.com, mayoclinic.org, and womenshealthmag.com. All provided accuracy statements and author credentials. The domain categorization taxonomy yielded a total of 101 unique categories. After grouping the websites that appeared less than 5 times, the most frequent categories involved "Health" (104/623, 16.69%), "Personal Pages and Blogs" (91/623, 14.61%), "Nutrition and Diet" (48/623, 7.7%), and "Exercise" (34/623, 5.46%). The risk of being a victim of a cyberattack was low. The findings suggested that while quality information is accessible, users may still encounter less reliable content among various online resources. Therefore, better tools and methods are needed to guide users toward trustworthy weight loss information.

Genetic analysis of children with nonsyndromic sensorineural hearing loss due to novel mutations/deletions of STRC bialleles

Objective: To investigate the clinical and genetic characteristics of nonsyndromic sensorineural hearing loss caused by STRC biallelic variation. Methods: A child with hearing impairment who was diagnosed at Gansu Provincial Maternal and Child Health Hospital on May 2022 and was selected as the research object. Peripheral blood of the child and her parents was collected, genomic DNA was extracted. IDT The xGen Exome Research Panel v2.0 whole exome capture chip was used to capture and sequence. Bioinformatics and clinical information analysis technology were used to analyze genetic data. The suspected pathogenic mutations were verified by quantitative polymerase chain reaction(QPCR)and Sanger sequencing. Results: The child had moderate hearing loss at about 1 year and 10 months, and now she is 3 years and 6 months, the hearing loss has not worsened. Whole exome sequencing(WES) testing revealed that the child carried the STRC gene with a deletion in EXON:1-29 and variants c.4561(exon24) _c.4562(exon24)insC, inherited from the mother and father, respectively. According to the relevant guidelines of the American Society for Medical Genetics and Genomics (ACMG), they were determined to be likely pathogenic variant and pathogenic variant. Conclusion: The discovery of c.4561(exon24) _c.4562(exon24)insC enriched the STRC variation spectrum, and provided a theoretical basis for the diagnosis and genetic counseling to the children.

Investigation of Temperature-Step Aging of Beef Sirloin on Techno-Functional and Microbiological Attributes

In today’s increasingly demanding market, there is a growing need for high-quality beef products that offer exceptional sensory attributes and provide a premium gastronomic experience. The aim of this research was to develop a beef aging technology that is food-safe (validated by microbiological measurement), produces meat with a desirable color and texture as well as techno-functional properties (drip loss, pH), and also minimizes aging time. The experiments included a temperature-stepped, anaerobic process carried out in vacuum packaging. According to the temperature steps, SAMPLE GROUP I remained at 5 °C throughout the four-week aging period. SAMPLE GROUP II transitioned to a 1 °C environment after the first week, while SAMPLE GROUP III moved from a 5 °C to a 1 °C environment after the second week, and SAMPLE GROUP IV moved after the third week. Instrumentally measured parameters, such as the drip loss, pH, color, texture, and microbiological characteristics of the fresh meat, and at each week of aging for each group, were examined and evaluated by ANOVA or MANOVA. The study found that the drip loss decreased during the first week of aging, then increased, with no strong correlation to temperature. The pH increased in the first week, then decreased, which is linked to microbiological processes, though the changes were not statistically significant. Anaerobic microbial counts rose across all groups but remained within safe limits. Texture analysis showed that meat tenderness peaked after the first week due to proteolytic activity, with Fmax showing significant group differences. Using the technology presented in this paper, optimal aging was achieved after one week, but trend-like results suggested further changes and furthering the aging process will develop a harder texture.

Production of Functional White Bread Enriched with Various Dietary Fibers with High Consumer Acceptance.

Fiber-enriched breads are inferior to wheat flour (white) breads in terms of volume, taste, and textural characteristics. The aim of this study was to produce functional dietary fiber (DF)-enriched white bread (WB) with high consumer acceptance. Wheat fiber (WF) was added to wheat flour as an insoluble fiber source (5%); polydextrose and inulin were used as soluble fibers at three different concentrations (2, 4, and 6%) individually or in combination. Their effects on dough rheology (farinograph and extensograph properties) and bread properties (volume, baking loss, moisture, texture, color, sensory, and crumb-grain characteristics) were investigated. The addition of WF, polydextrose and inulin had significant effects on dough rheology and bread properties. Hardness, chewiness, cell density, and DF content of breads were generally increased, whereas volume yield, baking loss, moisture and porosity values decreased with increasing DF concentration. The bread with the highest DF content (PD6IN6) contained 7.1 times more DF than WB. According to the results of sensory analysis, except for the sample with 6% concentration of polydextrose and inulin, all the other breads had very high overall acceptance values. Although the breads produced in the study have a high fiber content, their important quality characteristics (moisture content, volume yield, cell density, color values and sensory properties) are similar to those of WB. As a result, the overall quality characteristics of bread made with different dietary fibers were maintained, and functional WB enriched with DF were produced with high consumer acceptance.

Fe3O4‐doped highly electromagnetically shielded PAN‐PVP composite porous carbon films

AbstractWith the wide application of modern electronic devices, the problem of electromagnetic pollution is becoming more and more serious, and the demand for efficient electromagnetic shielding materials is becoming more and more urgent. To address this problem, we homogeneously mixed polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and triiron tetraoxide (Fe3O4) nanoparticles by solution blending, and prepared composite precursor membranes by taking advantage of the magnetic properties and good electromagnetic loss characteristics of Fe3O4, as well as the high thermal stability and film‐forming properties of PAN and PVP. Subsequently, carbonized PAN‐PVP/ Fe3O4 composite films with different Fe3O4 contents were successfully prepared by carbonization under high temperature inert atmosphere to convert PAN and PVP into carbon materials. It was found that the PAN‐PVP/ Fe3O4 porous carbon film with 3 wt% Fe3O4 addition had a conductivity of 3.99 S·mm−1 at a thickness of 0.42 mm, and an average EMI SET of 78.9 dB, SEA of 64.8 dB, and SSEt of 1838 dB/(cm2·g−1) in the X‐band, which is a typical wave absorbing material and can meet commercial electromagnetic shielding requirements. This work provides new ideas and methods for the research and development of polymer‐based porous carbonized film as electromagnetic shielding materials.Highlights The carbon films with rich porous structure were prepared. Fe3O4 was successfully embedded into the carbon film. Carbon films have an efficient conducting network. Carbon film has excellent electromagnetic shielding performance. The main shielding mode of carbon film is absorption.

Analysis of hydrodynamic and loss characteristics of hydrofoil under the effect of tip clearance

Tip leakage flow widely exists in fluid machinery, which affects the unit's mainstream flow state and induces significant flow loss. This study explores the relationship between vortex motion and hydraulic loss in the fluid field of single hydrofoil and tandem double hydrofoils under the effect of tip clearance. The validation work indicates that the simulation results in this study align with previous experimental findings, verifying the accuracy of the method employed herein. Further analysis reveals that: (1) The existence of clearance can induce a series of vortex structures such as tip leakage vortex(TLV), tip separation vortex(TSV), hairpin vortex(HV), and wingtip vortex(WTV). The length of TLV is greatly affected by increase of clearance width. The TLV and TSV undergo three stages of generation, development, and dissipation during the fluid flows though hydrofoil, greatly affecting flow stability. (2) Vortex motion is accompanied by significant turbulent pulsation, resulting in entropy production and inducing hydraulic loss. The calculation results indicate that approximately 75% of the loss is generated in the zones of midstream and downstream(V2+V3), where the vortex structure is full developed and the vortex motion is violent. Additionally, the loss caused by turbulent dissipation term accounts for 98%, while the loss caused by viscous dissipation accounts less 2%. (3) The loss in single hydrofoil is approximately positively correlated with the clearance width, while it fluctuates with the increase of width in tandem double hydrofoils.

Optimizing irrigation and planting strategies to prevent non-point source pollution in the Hetao Irrigation District using SWAT-MODFLOW-RT3D model

Non-point source (NPS) pollution is a significant issue in the Hetao Irrigation District (HID), affecting local water environment and ecological safety. To explore solutions for managing NPS pollution in the HID, this study establishes the SWAT-MODFLOW-RT3D (SMFR) model based on data from recent years. The results show that the determination coefficient (R2) of monthly drainage simulation for both the calibration and validation periods are >0.6, the Nash-Sutcliffe efficiency (NSE) values are >0.7, and the percent bias (PBIAS) values are <10 %. For pollutant transport simulation (total nitrogen and total phosphorus), the R2 values for both calibration and validation periods exceed 0.6, the NSEs are >0.75, and the PBIAS values are below 20 %. The model demonstrates good performance in simulating hydrology and pollutant transport in the study area, indicating strong applicability. Building on this, the spatial and temporal distribution characteristics of nitrogen and phosphorus losses in the HID were analyzed, and the impacts of different agricultural management practices, such as irrigation and fertilization regimes, drip irrigation under film (DIUF), and crop structure adjustments, on NPS pollution were assessed. Extensive scenario testing indicates that deficit irrigation and DIUF reduce total nitrogen (TN) in agricultural NPS pollution by 7.74 % and 9.34 %, respectively, and total phosphorus (TP) by 35.12 % and 40.99 %, respectively. In contrast, crop structure adjustments have a relatively moderate reduction effect on TN and TP, ranging from 2.66 % to 6.80 %. Additionally, the study examines the NPS pollution control effects of various combined scenarios. Through economic benefit evaluation, it was found that the scenario combining deficit irrigation with crop structure adjustments has a lower cost-effectiveness (CE) ratio and a higher cost-benefit (CB) ratio, making it a more favorable measure for controlling NPS pollution in the HID.

Partial loss and significant depletion of radiation belt electrons during the April 4, 2017, geomagnetic storm

We report a specular loss event of radiation belt electrons induced by a moderate geomagnetic storm on April 4, 2017, by using Van Allen Probe observations. During the initial phase, when the solar wind dynamic pressure (Pdyn) reached 12 nPa, the radiation belt electrons at Ek &amp;gt; ∼200 keV experienced a partial loss, followed by noticeable energy dispersion, which pronouncedly occurred at larger pitch angles on higher L shells. During the main phase, both probes witnessed a significant electron flux depletion at all energies from 54 to 2.6 MeV on the dusk-night side (MLT = magnetic local time around 20). Moreover, the corresponding phase space density (PSD) shows a local dip within L* = 4.44–4.87 (drift shell under adiabatic coordinate), which is not the outermost of L*, lasting for one pass (semi-period) of the spacecraft and quickly disappearing. By comparing the characteristics of electron loss in response to variations of the solar wind and geomagnetic indices, the movement of the estimated magnetopause location and the last closed drift shells, as well as the distribution of the plasma waves, we find that the partial dropout was essentially induced by the magnetopause shadowing effect, while the potential effect of the subsequent local PSD dip cannot be clearly explained by the present theory as far as we know. By showing the specular dropout event in the present work, we underline that the different loss effects should draw special attention from the space physics community.

Influence of side channel inlet angle on energy conversion of a side channel pump

The side channel pump generates several disadvantage vortices due to abrupt structural changes at the junction of the impeller and side channel, leading to unstable flow, which may induce severe vortex cavitation at the inlet section of the side channel, its impact on the pump's unstable flow mechanism and on the energy conversion characteristics has yet to be thoroughly investigated. This paper explores the effect of backflow vortex on pump performance through optimizing side channel inlet angles by combining the Ω criterion, helicity, and entropy production methods. The computational fluid dynamics numerical simulation's accuracy has been experimentally verified. It was found that increasing the side channel inlet angle could improve internal flow, thereby suppressing backflow vortices and promoting dynamic vortices formation in the inlet section. The backflow vortex is the primary source of high localized energy loss in the inlet section, significantly influencing the reduction of flow loss. It also reduces low pressure areas caused by backflow vortices, thus, restricting cavitation origin. In addition, within a certain range, the flat side channel pump enhances its hydraulic performance, exhibiting the best performance at a 60° inlet angle with an efficiency improvement of 4.6% at the Best Efficiency Flow Point (BEP), which has the most effective backflow vortex suppression, and therefore, lowest flow losses. However, the head improvement was negligible. The performance improvement is due to complete energy conversion within the inlet section. This paper offers new insights into the mechanisms underlying internal energy loss and cavitation characteristics in refining side channel pumps.