Electric vehicle (EV) systems require a high energy-efficiency traction motor so that the motors for EV traction should achieve high efficiency and power density. Hence, a permanent magnet ...synchronous motor (PMSM) for EV traction using a maximum slot occupation (MSO) coil has been investigated in this study. By applying the MSO coil, high torque density was achieved, but an additional loss, which decreases the efficiency, was incurred through alternating current (AC) resistance. To reduce the AC resistance of the MSO coil, the following process was performed: First, by investigation using the analytical method, pole/slot numbers, current density and number of parallel circuits affecting the frequency, the shape and number of conductors were chosen as important variables. Resistances of the MSO coil with a stator core were analyzed according to the chosen variables above. From the results, MSO coil applied PMSM with proper pole/slot numbers, current density, and parallel circuits was determined to improve the efficiencies at the base and maximum speeds. To accurately estimate the efficiency of the determined model, loss evaluation methods were explained. Subsequently, the determined MSO coil applied model was compared with the conventional model having round wires, and the improvements were verified by load testing.
Summary
Ornithine lipids (OLs) are bacteria‐specific lipids that are found in the outer membrane of Gram (−) bacteria and increase as surrogates of phospholipids under phosphate‐limited environmental ...conditions. We investigated the effects of OL increase in bacterial membranes on pathogen virulence and the host immune response. In Pseudomonas aeruginosa, we increased OL levels in membranes by overexpressing the OL‐synthesizing operon (olsBA). These increases changed the bacterial surface charge and hydrophobicity, which reduced bacterial susceptibility to antibiotics and antimicrobial peptides (AMPs), interfered with the binding of macrophages to bacterial cells and enhanced bacterial biofilm formation. When grown under low phosphate conditions, P. aeruginosa became more persistent in the treatment of antibiotics and AMPs in an olsBA‐dependent manner. While OLs increased persistence, they attenuated P. aeruginosa virulence; in host cells, they reduced the production of inflammatory factors (iNOS, COX‐2, PGE2 and nitric oxide) and increased intracellular Ca2+ release. Exogenously added OL had similar effects on P. aeruginosa and host cells. Our results suggest that bacterial OL plays important roles in bacteria‐host interaction in a way that enhances bacterial persistence and develops chronic adaptation to infection.
In this study, the radial vibration of fractional-slot concentrated winding (FSCW) permanent magnet synchronous motor (PMSM) was analyzed according to pole/slot combination considering phase ...relationship of modulated radial, tangential forces, and moment. First, to calculate the modulated forces and moment according to pole/slot combination, the amplitude and phase of modulated radial, tangential force and moment converted by radial air-gap electromagnetic force density (AEFD) are analytically derived. Since the lever arm effect by tangential force varies according to the tooth length, tangential force was translated on the yoke and an equivalent modulated moment was derived. Subsequently, to analyze the radial vibration caused by modulated forces and moment, the radial displacement response owing to a unit radial AEFD is calculated using 3D structural finite element analysis by applying unit modulated forces and moment. It was found out that the tooth modulation effect hardly varied with pole/slot combination and shape of the PMSM such as tooth length. Rather, it was confirmed that the tooth modulation effect was significantly influenced by the slot opening width. Especially, it was analyzed that the radial vibration of PMSM is not simply reduced by optimizing the slot opening width with reduced modulated radial force, but the amplitude and phase of the modulated tangential force and moment should also be considered. Finally, four prototypes of the PMSM with different slot opening widths of two 12-slot 10-pole and two 12-slot 14-pole are fabricated, and the test and simulation results are compared and verified.
Abstract
While many Ly
α
blobs (LABs) are found in and around several well-known protoclusters at high redshift, how they trace the underlying large-scale structure is still poorly understood. In ...this work, we utilize 5352 Ly
α
emitters (LAEs) and 129 LABs at
z
= 3.1 identified over a ∼9.5 deg
2
area in early data from the ongoing One-hundred-deg
2
DECam Imaging in Narrowbands (ODIN) survey to investigate this question. Using LAEs as tracers of the underlying matter distribution, we identify overdense structures as galaxy groups, protoclusters, and filaments of the cosmic web. We find that LABs preferentially reside in regions of higher-than-average density and are located in closer proximity to overdense structures, which represent the sites of protoclusters and their substructures. Moreover, protoclusters hosting one or more LABs tend to have a higher descendant mass than those which do not. Blobs are also strongly associated with filaments of the cosmic web, with ∼70% of the population being within a projected distance of ∼2.4 pMpc from a filament. We show that the proximity of LABs to protoclusters is naturally explained by their association with filaments as large cosmic structures are where many filaments converge. The contiguous wide-field coverage of the ODIN survey allows us to establish firmly a connection between LABs as a population and filaments of the cosmic web for the first time.
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•A hierarchical OER electrocatalyst with high activity and stability was fabricated.•Hydroxide was formed on the electrode surface synthesized by electrodeposition.•Surface morphology ...and structure relative to plating bath concentration were analyzed.•OER performance was examined with respect to the Ni:Fe ratio of the plating bath.•The optimized electrocatalysts demonstrated high OER performances in alkaline media.
This study fabricated an OER electrocatalyst with a hierarchical structure by electrodepositing Ni-Fe on NiO. The prepared electrocatalyst exhibited high activity and stability. Furthermore, the OER characteristics of the NiFe/NiO electrode were investigated by changing the metal (Ni and Fe) concentration and Ni:Fe ratio in the plating bath. As the plating bath concentration decreased, NiFe-layered double hydroxide was prominently formed due to an increase in local pH. The electrode obtained using a relatively low plating bath concentration of 130 mM demonstrated high activity with an overpotential of 245 mV and Tafel slope of 27.6 mV dec-1 at a current density of 10 mA/cm2. When the Ni:Fe ratio in the plating bath was adjusted, OER activity increased as the Fe content of the electrode increased to approximately 20.9 at.%, and as the Fe content increased beyond that, the activity gradually decreased. Fe inhibits Ni oxidation and acts as an active site owing to Fe3+ substitution in the γ-NiOOH structure, resulting in increased OER activity. However, when the Fe content was > 29 at.%, the inactive phase γ-FeOOH predominantly grew and the OER activity decreased.
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•Causes of Raney Ni-Fe electrode (de)activation in OER environments were examined.•Electrodes were subjected to accelerated deactivation tests under three conditions.•Zn/Fe leaching & ...NiO/Ni-Fe hydroxide formation were identified as influence factors.•Clues for enhancing Raney Ni–based electrode durability & performance were provided.
We investigated the (de)activation of Raney nickel–iron anodes in various oxygen evolution reaction (OER) environments using accelerated deactivation testing (ADT) under the conditions of on/off voltage control (ADT1), constant current density (ADT2), and cyclic voltammetry (ADT3). ADT1 caused activation under OER conditions by promoting the leaching of residual zinc and thus increasing the electrode surface area and oxygen vacancy content, whereas deactivation was observed under the conditions of the hydrogen evolution reaction(H-ADT1). ADT2 decreased the OER activity by promoting NiO formation and iron leaching, while ADT3 slightly increased the OER activity by favoring the incorporation of iron into the nickel lattice and promoting nickel–iron hydroxide formation. Thus, this work facilitates the design of more efficient and durable Raney nickel–based OER anodes by providing insights into their (de)activation mechanisms.
Although cranial autonomic symptoms (CAS) are typical in cluster headache (CH), some individuals with CH show no CAS during their headache attacks. Probable cluster headache (PCH) is a subtype of CH ...that fulfils all but one criterion of CH. This study aimed to investigate the frequency and clinical features of CH and PCH without CAS in comparison to those with CAS. We analysed data from the Korea Cluster Headache Registry, a prospective multicentre registry involving data from 16 hospitals. Of the 216 participants with CH and 26 with PCH, 19 (8.8%) and 7 (26.9%), respectively, did not have CAS. Participants with CH without CAS exhibited less severe anxiety (General Anxiety Disorder-7 score, median interquartile range, 2.0 1.0-6.0 vs 8.0 3.0-12.0, p = 0.001) and depression (Patient Health Questionnaire-9 score, 3.0 1.0-7.0 vs 7.0 3.0-11.0, p = 0.042) than those with CAS. Among participants with PCH, headache intensity was less severe in participants without CAS than in those with CAS (numeric rating scale, 8.0 7.0-8.0 vs 9.5 8.0-10.0, p = 0.015). In conclusion, a significant proportion of participants with CH and PCH did not have CAS. Some clinical features of CH and PCH differed based on the presence of CAS.
As the torque density of traction motors for electric vehicles (EVs) increases, winding technology with a large conductor area, such as hairpin winding, is widely used. However, it has a disadvantage ...of large AC copper loss affected by the skin and proximity effect. Therefore, the AC copper loss should be considered for deriving characteristics of IPMSM. This paper deals with the maximum torque per ampere (MTPA) and flux-weakening control characteristics of the IPMSM considering AC copper loss. As the AC copper loss is caused by armature and field excitation, a separation process of AC copper loss by each cause is proposed. By using the process, the separated AC copper loss can be analyzed according to the current vector and rotational speed. However, it is inefficient to calculate the AC copper loss according to rotational speed using transient analysis. Therefore, a computationally efficient method of calculating AC copper loss based on magneto-static analysis is presented. In addition, advanced d, q -axis equivalent model considering AC copper loss is proposed to analyze MTPA and flux-weakening control characteristics of IPMSM. By using the proposed d, q -axis equivalent model, the IPMSM can be designed considering the AC copper loss efficiently and accurately.
The three-reactor chemical-looping process (TRCL) for the production of hydrogen from natural gas is quite attractive for both CO
2 capture and hydrogen production. The TRCL process consists of a ...fuel reactor, a steam reactor and an air reactor. In the fuel reactor, natural gas is oxidized to CO
2 and H
2O by the lattice oxygen of the oxygen carrier. In the steam reactor, the steam is reduced to hydrogen through oxidation of the reduced oxygen carrier. In the air reactor, the oxygen carrier is fully oxidized by air. In this process, the oxygen carrier is recirculated among the three reactors, which avoids direct contact between fuel, steam and air. In this study, various candidate materials were proposed for the oxygen carrier and support, and a thermal analysis of the process was performed. The oxygen carrier for the process must have the ability to split water into hydrogen in its reduced state, which is a different chemical property from that of the chemical-looping combustion medium. The selection of the oxygen carrier and support require careful consideration of their physical and chemical properties. Fe
2O
3, WO
3 and CeO
2 were selected as oxygen carriers. Thermal analysis indicated an expected hydrogen production of 2.64 mol H
2 per mol CH
4 under thermoneutral process conditions. The results indicated that hydrogen production was affected mainly by the steam-conversion rate. The solid-circulation rate and temperature drop in the fuel reactor were calculated for the selected oxygen carriers with different metal oxide contents and solid-conversion rates.
Giant-cell arteritis (GCA) is the most common type of vasculitis in the elderly and is associated with high risks of visual loss and recurrence. Owing to its rarity in Asian populations, the current ...clinical interventions for these patients are not well known. Here we aimed to characterize the current management status of patients with GCA using Korean multicenter data.
This retrospective study analyzed medical records of patients with GCA at six Korean university hospitals from February 2009 to November 2022. GCA had originally been diagnosed based on the 1990 American College of Rheumatology (ACR) criteria, and cases were selected for inclusion in this study based on the 2022 ACR/European Alliance of Associations for Rheumatology criteria. We evaluated treatments, follow-up periods, and outcomes (relapse, remission, and adverse drug reactions) in patients with GCA with or without arteritic anterior ischemic optic neuropathy (AAION).
This study analyzed 18 patients with a median age of 75.5 years that included 12 females (66.7%). Seven patients (38.8%) had AAION. All patients initially received prednisolone treatment, while four (22.2%) underwent adjuvant treatment with methotrexate and azathioprine during prednisolone tapering. During the median follow-up of 3.5 months (interquartile range: 2.0-23.2 months), 4 patients (22.2%) had prednisolone-related adverse reactions, 2 (11.1%) relapsed, and 13 (72.3%) dropped out. Nine patients (50.0%) experienced remission, with this being sustained in four (36.4%).
This study observed high dropout rates and short follow-ups. Adverse effects of prednisolone were common, and relapses occurred in approximately one-tenth of Korean patients with GCA. Thus, optimizing GCA treatment necessitates regular monitoring and long-term follow-up.
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