Transient Losses Research Articles

Estimation of the Risk of Hearing Loss in Neonates with Hyperbilirubinemia in the Mysuru District Using Double Stage Double Screening Method.

The study aimed to assess the risk of hearing loss in full-term neonates with hyperbilirubinemia, examining the relationship between bilirubin levels, onset age of hyperbilirubinemia, and hearing impairment. Additionally, it investigated whether hearing loss was transient or late-onset, using a cost-effective double-screening method. The study included 160 full-term neonates aged 0-1 month. Following completion of phototherapy for hyperbilirubinemia, all infants underwent initial screening with otoacoustic emissions (OAEs) and automated auditory brainstem responses (AABR). A second screening was administered to all infants within one month. Infants referred during the second screening, regardless of their first screening results, underwent diagnostic evaluation. For analysis, the infants were categorised into 4 groups, based on their bilirubin levels and onset of jaundice. After the initial screening, 37% of infants were referred, which decreased to 9% after subsequent screening, suggesting transient hearing loss in 76% of initially referred infants. Permanent hearing impairment was confirmed in 2.5% of infants following diagnostic evaluation, with 3 infants diagnosed with ANSD and 1 infant with sensorineural hearing loss, all from categories characterized by elevated bilirubin levels. The findings indicated that even bilirubin levels as low as 12 to 15 mg/dl could lead to hearing loss, particularly when jaundice onset occurred early. This study highlights the effectiveness of double-screening for identifying transient hearing losses in infants with hyperbilirubinemia, minimizing the need for diagnostic referrals. It underscores the importance of considering both bilirubin levels and onset timing to assess auditory risk fully.

Computerized Axiographic Findings in a Cohort of Migraine Patients: A Cross-Sectional Study.

The objective of this work was to investigate the association between the function of the stomatognathic system and migraine presence through an instrumental functional analysis in a group of diagnosed migraine patients and a control group. This study included 50 individuals in each group. A jaw-tracking analysis was performed using Cadiax 4. Tracings of the following movements were recorded: open/close, protrusion/retrusion, mediotrusion, speech, bruxing, and mastication. The tracings were evaluated for their quantity, quality, transversal characteristics, speed, curvature pattern, and condylar stability. Statistically significant differences between the groups were established for several aspects of the evaluation. Migraineurs presented with (a) higher values of mandibular lateral translation in protrusion/retrusion (p = 0.001), open/close (p = 0.031), and mastication (p = 0.016); (b) transient velocity losses in open/close (p = 0.001) and protrusive movements (p = 0.018); (c) a compromised condylar stability for protrusion/retrusion (p = 0.001) and mediotrusion (p = 0.003); (d) a compromised quality for protrusion/retrusion (p < 0.001) and mediotrusion (p = 0.003); and (e) a more frequent "figure-eight" curvature in open/close (p = 0.012). The importance of the stomatognathic function in migraine pathogenesis and treatment should be considered by using a patient-centered and interdisciplinary approach.

The Bredehoeft problem: Evaluating salvage during groundwater pumping in unconfined aquifers

During groundwater pumping from unconfined aquifers, evapotranspiration can be reduced as the water table drops, a process known as salvage. This phenomenon must be included in water balance assessments for accurate predictions of groundwater withdrawals. Although the salvage phenomenon has been well understood for a long time, i.e., since Theis’ pioneering studies, the models that were later developed by Bredehoeft always relied on numerical techniques to treat the inherent non-linearity, most commonly using MODFLOW. Analytical methods have been previously used with success for practical evaluation of water balance components such as stream depletion rates. This work presents a novel analytical solution of the Bredehoeft problem. It is a breakthrough in analytical evaluation of transient salvage losses induced by groundwater withdrawals due to declines of water table. We evaluate stream depletion and loss of storage in addition to salvage, using the new model. Detailed analysis of the solution using COMSOL software indicates that the linear approximation used in the analytical solution is accurate for most practical cases. Diagrams for drawdown, water balance and evaluation of solution accuracy are presented, considering a broad range of problem parameters. Results can be used for analyses of watershed-scale water balances.

Abstract LB155: Intra-cranial administration of MTL-004, a promising post-resection treatment for glioblastoma

Abstract Objectives Gliomas (GBM), are exceptionally hard to treat, aggressive and genetically heterogeneous tumors. This study reports the control of tumor recurrence and improved survival in male and female rats by combining a single intra-cranial dose of MTL-004 (5-(aziridine-1- yl)-4 hydroxylamino-2-nitrobenzamide), in a bioresorbable paste (a blend of poly DL-lactic acid-co-glycolic acid; (PLGA) and poly ethylene glycol; (PEG)) to surgical resection of primary glioma tumors. Comparison is made with oral temozolomide (TMZ), the current standard of care (SOC), following resection. Experimental procedures On day 0, 2 mm3 tumor fragments were implanted into the brains of healthy female and male Fischer rats. On day 5 rats the growing tumors were removed using microsurgery. Treatments started as follows: •Group 1 (Placebo) received a single intracranial dose of excipient powder in PGLA/PEG paste; •Group 2 (SOC) received 5 daily oral doses of TMZ at 50 mg/kg; •Group 3 (MTL-004) received a single intracranial dose of excipient powder containing 1 mg/kg MTL-004 in PGLA/PEG paste. Results Body Weight Between day 0 and 5, no groups had statistically significant body weight changes. Between days 5 to 9, mean body weight of rats receiving TMZ was significantly reduced. Tumor Volumes Tumor volumes from MRI were evaluated when at least 80% of rats were still alive in each group (day 14 post tumor resection/treatment initiation). Mean tumor volume was significantly higher in the placebo groups compared to MTL-004 and TMZ treatments. Survival Rats were studied for 58-days post tumor resection/treatment. At this time out of twelve rats per group, none or one survived on TMZ, two or no animals were still alive on placebo, and seven or ten rats treated with MTL-004 were still alive (male or female respectively). Post resection median survival time was between 20.5 to 27.5 days for rats treated with oral placebo or TMZ. Rats treated with MTL-004 had a significantly higher survival compared to both placebo and TMZ groups and remained in apparent good health for the 58 days of the study. Conclusions Consistent trends were observed in each group of male and female rats following tumor resection. •PGLA/PEG paste with MTL-004 or without (placebo) or were both well tolerated. •Treatment with MTL-004 in PGLA/PEG paste provided good tumor control, was better tolerated and led to significantly greater survival than oral TMZ or placebo. •Oral TMZ (SOC) provided control of tumor volume but was associated with significant, transient body weight losses and no significant survival gain compared to placebo. Our data highlight significant survival benefits associated with a single intracranial dose of MTL-004 with PLGA/PEG paste post-surgery. In conclusion, surgery followed by MTL-004 in PGLA/PEG paste is a well-tolerated and promising treatment for glioblastoma, suitable for clinical evaluation. Citation Format: Mike Hudson, Sylvie Maubant, Elisabeth Bertrand, Marie Lux, Jordan Longin, Elodie Marie Dit Chatel, Maxime Ramelet, Olivier Duchamp. Intra-cranial administration of MTL-004, a promising post-resection treatment for glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB155.

Research on Transient Electromagnetic Field and Eddy Current Losses Reduction in End of Large-Capacity Synchronous Condenser During UHVDC System Faults

Research on Transient Electromagnetic Field and Eddy Current Losses Reduction in End of Large-Capacity Synchronous Condenser During UHVDC System Faults

A transient heat losses model for two-tank storage systems with molten salts

Concentrating Solar Power (CSP) is a proven and mature technology for energy supply. In recent years, electricity generation based on this technology has increased worldwide, to a large degree due to its high dispatchability when coupled with an energy storage system. Commercially, most plants store the energy in molten salts in a two-tank configuration. This study focuses on this storage configuration and proposes a mathematical model for the thermal losses in these tanks, both at nominal conditions and during transients. With this model at its core, a computational tool for thermal performance analysis in OpenModelica is developed. This dynamic thermal model includes the estimation of local heat loss due to assembly defects, which are heat flows that cannot be determined by theoretical modelling. The development of a semi-empirical correlation for estimating local heat loss is also presented. Simulation results showed that this local heat loss may represent a share about 40% of the total heat loss in a small-scale tank. A comparison of the characteristics of the model proposed in a previous work is also presented to establish the innovation of the model. Two thermal storage systems with different tank designs and sizes were simulated to compare the results using the present model with data available in the literature. Results show good agreement in transient thermal behaviour of heat flows, temperatures, and cooling rates when compared with data from other authors for the same tank.

Ultra-Fast and Accurate MPPT Control Structure for Mobile PV System Under Fast-Changing Atmospheric Conditions

Photovoltaic (PV) system efficiency is highly dependent on atmospheric conditions, which are continuously varying. The presence of an efficient maximum power point tracking (MPPT) method suitable for fast-changing environmental conditions, even under partial shading conditions (PSC) is required to optimize the PV system efficiency. This paper proposes a different MPPT control structure, where the MPPT is nested in the proportional-integral (PI) voltage controller routine. By using the proposed control structure. The Analog-to-Digital Converter (ADC) samples are shared between the MPPT algorithm and PI controller. As a result, extreme dynamic tracking improvements while a cost-effective implementation is ensured. Using the proposed control structure, a high-speed MPPT is achieved, making it suitable for mobile PV systems subjected to fast-changing atmospheric conditions. As the tracking accuracy is high, the P&O subroutine usually used in GMPPT methods to maintain the GMPP is eliminated. Results revealed that with the proposed implementation scheme, the tracking speed and the transient energy losses can be four times better than the traditional scheme.

Performance of Recursive Least Squares Algorithm Configurations for Online Parameter Identification of Induction Machines in an Automotive Environment

The recursive least squares algorithm for online parameter identification of induction machines has a high potential to serve as a basis for an innovative electric vehicle diagnosis concept. Commonly used for control parameter tuning, this approach is established in numerous industrial applications. However, in the automotive environment, special machine designs are used and highly dynamic operation takes place in a wide speed and load range. This results in fast transient parameter behavior, which is challenging in terms of online parameter identification. Therefore, the algorithm performance must be rated in our field of application with suitable dynamic test profiles. In this work, we compare several algorithm extensions to a novel recursive least squares algorithm with multiple variable forgetting factors for induction machines. The algorithms are analyzed regarding their handling of the associated transient parameter behavior. In addition, different identification model structures are considered to deal with the dynamic speed operation and the associated transient iron losses. Special attention is given to the real-time performance of the overall identification algorithms as this is a major requirement for implementation in automotive embedded systems. For validation, both, simulation and experimental results are presented, and associated configuration recommendations are provided.

Evaluation of Frequency Loss Induced Quench Protection Prototype at 77 K Using HTS Coils

A prototype design of the Frequency Loss Induced Quench (FLIQ) protection system for high temperature superconducting magnets was validated on a small Second-Generation High-Temperature Superconducting (2G HTS) coil. Calorimetric measurements, based on liquid nitrogen boil-off rate, were performed to quantify the heat energy introduced by FLIQ system in the coil. The technique was previously used for steady state AC loss measurements and adopted for the transient losses generated in FLIQ operation. A series of tests of the FLIQ system on 2G HTS pancake coils were performed to study the dynamics of the quench and the energies involved in the quenching process. The results suggest the suitability of the FLIQ technique for quench protection of HTS coils. A measurement protocol of extended repetitive high-frequency current pulses established in the study provided a way to estimate the energy deposited by the AC losses generated in the coil by the FLIQ system. The measurement method described is a practical way to validate the design parameters of the FLIQ system and to evaluate the sensitives of the various design parameters of the FLIQ. The paper reports an experimental technique used to study the sensitivities of various FLIQ design parameters by establishing and measuring quasi-equilibrium heat load and boil-off rate as a result of extended repetitive high-frequency current pulses.

Identification of Potential Novel B-Cell Epitopes of Capsid Protein VP2 in Senecavirus A.

Senecavirus A (SVA) is a type of nonenveloped single-stranded, positive-sense RNA virus. The VP2 protein is a structural protein that plays an important role in inducing early and late immune responses of the host. However, its antigenic epitopes have not been fully elucidated. Therefore, defining the B epitopes of the VP2 protein is of great importance to revealing its antigenic characterization. In this study, we analyzed B-cell immunodominant epitopes (IDEs) of the VP2 protein from the SVA strain CH/FJ/2017 using the Pepscan approach and a bioinformatics-based computational prediction method. The following four novel IDEs of VP2 were identified: IDE1, 41TKSDPPSSSTDQPTTT56; IDE2, 145PDGKAKSLQELNEEQW160; IDE3, 161VEMSDDYRTGKNMPF175; and IDE4, 267PYFNGLRNRFTTGT280. Most of the IDEs were highly conserved among the different strains. To our knowledge, the VP2 protein is a major protective antigen of SVA that can induce neutralizing antibodies in animals. Here, we analyzed the immunogenicity and neutralization activity of four IDEs of VP2. Consequently, all four IDEs showed good immunogenicity that could elicit specific antibodies in guinea pigs. A neutralization test in vitro showed that the peptide-specific guinea pig antisera of IDE2 could neutralize SVA strain CH/FJ/2017, and IDE2 was identified as a novel potential neutralizing linear epitope. This is the first time VP2 IDEs have been identified by using the Pepscan method and a bioinformatics-based computational prediction method. These results will help elucidate the antigenic epitopes of VP2 and clarify the basis for immune responses against SVA. IMPORTANCE The clinical symptoms and lesions caused by SVA are indistinguishable from those of other vesicular diseases in pigs. SVA has been associated with recent outbreaks of vesicular disease and epidemic transient neonatal losses in several swine-producing countries. Due to the continuing spread of SVA and the lack of commercial vaccines, the development of improved control strategies is urgently needed. The VP2 protein is a crucial antigen on the capsids of SVA particles. Furthermore, the latest research showed that VP2 could be a promising candidate for the development of novel vaccines and diagnostic tools. Hence, a detailed exploration of epitopes in the VP2 protein is necessary. In this study, four novel B-cell IDEs were identified using two different antisera with two different methods. IDE2 was identified as a new neutralizing linear epitope. Our findings will help in the rational design of epitope vaccines and further understanding of the antigenic structure of VP2.

Protocolo diagnóstico-terapéutico del paciente con pérdida aguda de visión

Recent vision loss is a common complaint, more often unilateral than bilateral. The temporal pattern of onset may be classified into transient, hyperacute, acute, and subacute-chronic losses, and the presence or absence of pain is also a relevant criterion. Among transient losses, amaurosis fugax is worth highlighting because it may herald an established ischemic stroke. Among hyperacute losses, urgent diagnosis of central retinal artery occlusion is imperative, given the possibility of reperfusion treatment with alteplase (off-label) in the first 4.5hours. In acute forms, the presence or absence of papillitis distinguishes between anterior and posterior (or retrobulbar) optic neuropathies, the latter being typical of demyelinating processes. In either transient, hyperacute and acute forms, and especially in the context of pain, identification of an arteritic process is mandatory as it would dictate the urgent initiation of corticosteroid therapy.

Thermodynamic mechanism of high energy performance of air source heat pump with coupled liquid-storage to gas-liquid separator

This study proposed a novel air source heat pump system (NASHPs) with coupled liquid-storage and gas-separator to prevent an air source heat pump (ASHP) from frosting. Compared to the original air source heat pump system (OASHPs), the proposed system delayed frost by 30 min and shortened defrosting time by 72 s in a cycle. To further study the mechanism of NASHPs, coefficient of performance (COP), transient losses (heating loss due to frosting and recovery) and defrosting losses (heating loss due to defrosting) of NASHPs and OASHPs were analysed based on experimental data. Furthermore, the thermodynamic perfectibility was introduced to reflect the degree of deviation of the actual operation performance of NASHPs from the theoretical energy efficiency. The maximum reduction of thermodynamic perfectibility in the actual running condition for NASHPs was observed to be approximately 26.5%, which caused the actual continuous energy efficiency of NASHPs to exhibit a certain gap with the energy efficiency of the ideal cycle. The transient loss of NASHPs indicated that the heat loss in the frosting and recovery stages was mainly due to the irreversible loss of the compressor and condenser. Moreover, the defrosting loss of the NASHPs was mainly due to the longer defrosting time and high temperature difference between the supply and return during defrosting. The energy efficiency in the continuous operation of the NASHPs plays a crucial role in the actual operation, and the defrosting loss significantly impacts the actual energy efficiency of the NASHPs compared to transient loss. We believe the results of this study provide a basis for the design and energy efficiency improvement of ASHP systems.

Impact of intrinsic properties and interface contacts on thermoelectric transient supercooling

The thermoelectric transient supercooling is expected to significantly suppress temperature rise in electronic devices since Peltier cooling has the highest response rate among various refrigeration techniques. Conventional researches assume that the better transient supercooling performance is predicated on zT as high as possible, while the power factor is overlooked. And there is a lack of methods to quantify the interface effect on transient supercooling losses. Here, using a series of numerical simulations and experimental methods, we found that the overall transient benefit only depends on the final zT value of materials, but the higher power factor will lead to a shorter response time and lower overshoot temperature. And thermal contact resistance (TCR) and electrical contact resistance (ECR) negatively impact transient supercooling, but the ECR is worse. Finally, the impact of semiconductors-metal interface resistance on transient supercooling was precisely investigated by in-situ measurement and agreed well with the numerical results. The TCR and ECR interface losses lead to an overall transient benefit reduction of 11% and 43% at two times the optimum current and ten seconds pulse width. The present results have an excellent reference for quantifying the effect of intrinsic properties and interface contacts on transient supercooling.

High-temperature heat recovery from a solar reactor for the thermochemical redox splitting of H2O and CO2

The solar splitting of H2O and CO2 via a thermochemical redox cycle offers a viable pathway for producing sustainable drop-in fuels for the transportation sectors. The key performance metric is its solar-to-fuel energy efficiency, which is strongly dependent on the ability to recover heat during the temperature swing between the reduction and oxidation steps. Here we report on the experimental investigation of a novel heat recovery method based on coupling the solar reactor with two thermocline energy storage units made of a packed-bed of alumina spheres. Using N2 as an inert heat transfer fluid, the heat rejected during cooling from the reduction to the oxidation temperature is stored and, following the oxidation step, delivered back to preheat the solar reactor towards the reduction temperature, thus reducing the required solar input and consequently increasing the efficiency. With a first experimental prototype, a heat extraction effectiveness of up to 70% from a 4 kW solar reactor is obtained with measured N2 outlet temperatures exceeding 1250°C. Energy flow modeling of a 50 kW solar reactor predicts a theoretical upper limit value of the energy efficiency of 42% for perfect heat recovery without transient losses, and 14.7% with such losses included. Several improvements and insights into high-temperature heat recovery are detailed.

Optimal Control of a PHEV Based on Backward-Looking Model Extended with Powertrain Transient Effects

The paper proposes a power flow control strategy for a P2 parallel plug-in hybrid electric vehicle (PHEV) which takes into account torque and power losses related to engine-on and gear shift transients. An extended backward-looking (EXT-BWD) model is proposed to account for the transient losses, while the control strategy combines a rule-based controller with an equivalent consumption minimization strategy. To describe the transient losses, the EXT-BWD model includes additional state variables related to engine on/off flag and gear ratio in the previous time step. To establish a performance benchmark for control strategy verification, a dynamic programming-based control variable optimization framework is established based on the EXT-BWD model. The proposed control strategy is demonstrated to improve the fuel efficiency and drivability compared to the original control strategy while retaining comparable computational efficiency.

Operational stability, low light performance, and long-lived transients in mixed-halide perovskite solar cells with a monolayer-based hole extraction layer

Due to their tunable bandgap and low manufacturing cost, metal halide perovskite solar cells are attractive for ambient/indoor light-harvesting applications. In this work, we evaluate p-i-n perovskite solar cells fabricated with MeO-2PACz, a molecular monolayer hole extraction layer, as potential candidates for ambient light-harvesting applications. Two triple-cation mixed halide lead perovskite absorbers are compared, one with high bromide content (Br/I ratio 1:2, bandgap 1.72 eV, 16.1% power conversion efficiency) and one with low bromide content (Br/I ratio 1:11, bandgap 1.57 eV, 19.1% power conversion efficiency). Both materials demonstrated good stability while operating under simulated sunlight at the maximum power point for 100 h, a cumulative light dose comparable to over two years of ambient use. After 100 h operation, however, the measured device efficiency fell temporarily due to a transient loss of output current before returning to the nominal level after a long recovery period in the dark. These transient losses were more apparent in the wide bandgap device under strong light and were likely caused by light-induced halide segregation. After recovery, both devices retained good performance under a wide range of light intensities. Under a simulated ambient light source (835 lx white LED), the power conversion efficiency of the wide bandgap device reached 30.4%.

Design of a Curved Superconducting Combined Function Bending Magnet Demonstrator for Hadron Therapy

Curved superconducting bending magnets have clear potential for compact hadron therapy gantries and medical synchrotrons. A combined function superconducting bending magnet design based on collared cos-theta coils is proposed for a new compact and cost-effective hadron therapy gantry initiative. This 3 T magnet, based on the technologies extensively developed for the LHC project, includes several gantry-specific features that shall be developed and validated with a demonstrator magnet. The main development areas include fabrication of epoxy-impregnated cos-theta Nb-Ti coils with 2.2 m radius of curvature along with the assembly of the surrounding curved cold mass. This paper presents the magnetic and mechanical design optimization of the proposed demonstrator magnet, the results of the numerical modelling of the transient losses during operation as well as the magnet quench protection analysis.

Modeling and analysis of energy losses under transient conditions in induction motors

&lt;span&gt;The present study is mainly concerned with solving the problems associated with energy losses resulting from starting transient conditions. In the present study, the possibilities of decreasing starting transient condition energy losses are investigated. Additionally, a comparison of the energy losses using different starting methods is also conducted. In this work, a complete description for deriving the equations used to calculate energy losses, mathematical analysis of the energy losses, the models of the different methods in this work were simulated using MATLAB/Simulink; and the results of energy losses and the dynamic characteristics are provided. Simulation results showed that the minimum starting energy losses were accomplished by soft starting method, in which the starting current could be reduced to the minimum value.&lt;/span&gt;

Q-Learning Relay Placement for Alert Message Dissemination in Vehicular Networks

Alert message (AM) dissemination is a fundamental yet challenging issue in vehicular networks, as it relies on wireless transmissions in a highly mobile, potentially dense, and changing environment. Emerging network infrastructure-based vehicular networks are being considered as an alternative to Vehicular Ad-hoc NETworks (VANETs) for alert message dissemination. Indeed, assuming that Vehicle to Infrastructure (V2I) communication links are nominally available, with some transient and time-limited connectivity losses, recent alert message dissemination schemes primarily rely on V2I links to widely broadcast AMs. Vehicle to Vehicle (V2V) rebroadcasts performed by some selected relay vehicles located within pre-computed rebroadcast zones are then used to ensure the full dissemination within an area of interest. This paper focuses on rebroadcast zones placement. It proposes a Q-learning-based method that computes the minimum number and optimal locations of rebroadcast zones. From these computed zones, the combination of V2I broadcasts with V2V rebroadcasts allows the delivery of AMs in a whole area, even in the presence of locations with poor wireless connectivity. The performance results show that high information coverage and low delivery delays are achieved with our proposed Q-learning based placement. Useless duplicate rebroadcasts and collisions are also avoided, saving network resources.

Voltage Track Optimizer Based Maximum Power Point Tracker Under Challenging Partially Shaded Photovoltaic Systems

In this article, a voltage track optimizer based maximum power point tracking controller for photovoltaic systems under challenging partial shading conditions is presented. The proposed method aims to optimize the operating voltage track while searching for the global maximum power peak (GMPP). This is achieved by bounding the search area by dynamic lower and upper voltage limits. In addition, an improved skipping mechanism is integrated to avoid scanning the unnecessary areas that do not contain the GMPP by exploiting the critical observations in the P-V and I-V curves. Furthermore, the initial operating voltage is exploited to accelerate the tracking speed. By doing so, the voltage track length is drastically reduced, which results in reducing the tracking time. The performance of the proposed method is evaluated against two recent GMPPT methods, namely improved team game optimization and modified maximum power trapezium through MATLAB/Simulink environment. Besides, the simulation results are verified experimentally via a buck-boost converter. The obtained results prove the superiority of the proposed algorithm against the compared algorithms in terms of voltage track length, tracking speed, and transient energy losses.