Numerical model of journal bearing lubrication considering a bending stiffness effect

An analysis for operating characteristics of journal bearing lubrication system is performed based on the numerical model. Dynamic bearing lubrication characteristics such as oil film pressure and thickness distribution can be analyzed through a numerical model with an integration of elastohydrodynamics and multi-flexible-body dynamics (MFBD). In particular, the oil film thickness variation by elastic deformation is considered in the elastohydrodynamic analysis by applying the bending stiffness effect of journal. And the oil film thickness variation by the bending stiffness effect is applied to the fluid governing equations to calculate the oil film pressure in the elastohydrodynamic lubrication region. A series of process proposed in this study is available for the analysis of realistic elastohydrodynamic lubrication phenomenon. Also, a numerical example for the journal bearing lubrication system is demonstrated and compared with the experimental results. The numerical results considering the bending stiffness effect show a good agreement with the experimental results

FE implementation of HAH model using FDM-based stress update algorithm for springback prediction of AHSS sheets

The homogeneous anisotropic hardening (HAH) model was implemented into a finite element (FE) code in order to predict springback for an advanced high strength steel (AHSS) sheet sample after double-stage U-draw bending. The finite difference method (FDM) was utilized as an alternative way to calculate the derivatives of this advanced distortional plasticity model allowing the update of the equivalent plastic strain and stress tensor at each time step in the user-material subroutines (UMAT and VUMAT). The FDM makes it easier to derive the stress gradient of complex yield surfaces. The proposed FDM-based stress update algorithm was verified by comparing the springback profiles after the single- and double-stage U-draw bending tests for a DP980 sheet sample predicted with analytical and numerical approaches. In addition, the springback measurement parameters and computational efficiencies depending on both approaches were also compared. The results indicate that the computational efficiency and accuracy of the FE simulations with the FDM-based stress update algorithm were similar to those of the analytical method. © 2018 Institute of Physics Publishing. All rights reserved.11Ysciescopu

Zero-frequency Bragg gap by spin-harnessed metamaterial

The Bragg gap that stops wave propagation may not be formed from zero or a very low frequency unless the periodicity of a periodic system is unrealistically large. Accordingly, the Bragg gap has been considered to be inappropriate for low frequency applications despite its broad bandwidth. Here, we report a new mechanism that allows formation of the Bragg gap starting from a nearly zero frequency. The mechanism is based on the finding that if additional spin motion is coupled with the longitudinal motion of a mass of a diatomic mechanical periodic system, the Bragg gap starting from a nearly zero frequency can be formed. The theoretical analysis shows that the effective mass and stiffness at the band gap frequencies are all positive, confirming that the formed stop band is a Bragg gap. The periodic system is realized by a spin-harnessed metamaterial which incorporates unique linkage mechanisms. The numerical and experimental validation confirmed the formation of the low-frequency Bragg gap. The zero-frequency Bragg gap is expected to open a new way to control hard-to-shield low-frequency vibration and noise

A case of Creutzfeldt–Jakob disease in a patient on hemodialysis

abstractWe report an unusual case of probable Creutzfeldt–Jakob disease (CJD) in hemodialysis patient. A woman 59 years of age with a past history of hypertension and end-stage renal disease presented with a stuporous state preceded by rapidly progressive cognitive dysfunction, myoclonus, and akinetic mutism. At first, the cause of the altered mental status was assumed to be uremic or hypertensive encephalopathy combined with fever. Proper managements, however, did not improve the neurologic symptoms. Diffusion-weighted magnetic resonance imaging revealed bilaterally asymmetric high signal intensity in both basal ganglia and cerebral cortices. Electroencephalography showed diffuse generalized theta-to-delta range slow wave and intermittent medium-to-high voltage complexes with a characteristic triphasic pattern on both hemispheres. Cerebrospinal fluid assay for the 14-3-3 protein was positive and diagnostic of CJD

Injection laryngoplasty of human adipose-derived stem cell spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx

As the geriatric population increased, the need of treatment for laryngeal atrophy and dysfunction increased. This study was performed to evaluate the effects of injection of human adipose-derived stem cell (hASC) spheroid-loaded catechol-conjugated hyaluronic acid (HA-CA) hydrogel on therapeutic rejuvenation of the geriatric larynx. Stem cell spheroids with hyaluronic acid-based hydrogel were injected into the laryngeal muscles of 18-month-old Sprague–Dawley rats. The effects of hASC spheroids were examined in the following four groups: SHAM, injected with PBS; GEL, injected with HA-CA hydrogel; MONO, injected with single hASCs in HA-CA hydrogel; and SP, injected with hASCs spheroids in HA-CA hydrogel. The rejuvenation efficacy in geriatric laryngeal muscle tissues at 12 weeks postinjection was evaluated and compared by histology, immunofluorescence staining, and functionality analysis. Total myofiber cross-sectional area and myofiber number/density, evaluated by detection of myosin heavy chain with antibodies against laminin and fast myosin heavy chain, were significantly higher in the SP group than in the other groups. The lamina propria of the larynx was evaluated by alcian blue staining, which showed that the HA was increased significantly in the SP group compared to the other groups. In functional analysis, the glottal gap area was significantly reduced in the SP group compared to the other groups. The phase difference in the vocal fold during vibration was also smaller in the SP group than in the other groups, but the difference did not reach statistical significance. Injection of hASC spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx.This research was supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Korean government (MSIT), Republic of Korea (No. 2019M3A9H1103617 and No. 2020R1A4A4079931), a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (No. HI14C1277) and the Tech-nology Innovation Program (or Industrial Strategic Technology Development Program-Bio-industrial technology development- customized diagnostic treatment products) (No. 20014955, Devel-opment of Intelligent Automation System for mass production of cell therapy products) funded By the Ministry of Trade, Industry & Energy (MOTIE), Republic of Korea

Development of a dual optical fiber probe for the hydrodynamic investigation of a horizontal annular drive gas/liquid ejector

A dual-channel optical fiber probe was developed to quantify the bubble characteristics (void fraction, velocity, and bubble size) in a gas–liquid annular ejector system. Water is pumped upstream of the ejector contraction. Since a low pressure region exists downstream in the ejector diffuser, this permits air to be sucked into the flowing liquid by jet pump action and the inlet air volumetric flow rate is measured by a flow meter. Verification of the void fraction (range 0.15–0.5) measured by the optical fiber probe was then possible and deviations were generally around ± 5%. Also, bubble velocity was measured using the optical probe by cross-correlating signals from the two fibers whose tips are separated by a known distance. Alternatively measuring bubble velocity using a particle image velocimetry method provided validation for the optical fiber probe system where a high speed camera was used to capture instantaneous bubble images at time intervals of 0.125 ms. Excellent agreement between the velocities using both methods is reported. For bubble size measurements, analyzing the temporal signals from a single probe enabled estimation of the size of a bubble. Bubble sizes measured ranged between 1.5 and 6.0 mm and size distributions were constructed for different ejector water volumetric flow rates ranging from 0.0022 to 0.0063 m3/s. LabVIEW provided a convenient platform for coding the algorithms for estimating the void fraction, bubble velocity and bubble size. For further comparison, a CFD study of the ejector system was done, and the vertical radial profiles of the void fraction were compared with those obtained by the optical fiber system and these showed good agreement

Safety and optimal neuroprotection of neu2000 in acute ischemic stroke with reCanalization: study protocol for a randomized, double-blinded, placebo-controlled, phase-II trial

BACKGROUND: The potential of neuroprotective agents should be revisited in the era of endovascular thrombectomy (EVT) for acute large-artery occlusion because their preclinical effects have been optimized for ischemia and reperfusion injury. Neu2000, a derivative of sulfasalazine, is a multi-target neuroprotectant. It selectively blocks N-methyl-D-aspartate receptors and scavenges for free radicals. This trial aimed to determine whether neuroprotectant administration before EVT is safe and leads to a more favorable outcome. METHODS: This trial is a phase-II, multicenter, three-arm, randomized, double-blinded, placebo-controlled, blinded-endpoint drug trial that enrolled participants aged ≥ 19 years undergoing an EVT attempt less than 8 h from symptom onset, with baseline National Institutes of Health Stroke Scale (NIHSS) score ≥ 8, Alberta Stroke Program Early CT score ≥ 6, evidence of large-artery occlusion, and at least moderate collaterals on computed tomography angiography. EVT-attempted patients are randomized into control, low-dose (2.75 g), and high-dose (5.25 g) Neu2000KWL over 5 days. Seventy participants per group are enrolled for 90% power, assuming that the treatment group has a 28.4% higher proportion of participants with functional independence than the placebo group. The primary outcome, based on intention-to-treat criteria is the improvement of modified Rankin Scale (mRS) scores at 3 months using a dichotomized model. Safety outcomes include symptomatic intracranial hemorrhage within 5 days. Secondary outcomes are distributional change of mRS, mean differences in NIHSS score, proportion of NIHSS score 0-2, and Barthel Index > 90 at 1 and 4 weeks, and 3 months. DISCUSSION: The trial results may provide information on new therapeutic options as multi-target neuroprotection might mitigate reperfusion injury in patients with acute ischemic stroke before EVT

Footwear Design Crowdsourcing Platform Model For Strengthening Of the Competitiveness Of The Footwear Industry

The volumes of global footwear production and consumption have been steadily increasing. In particular, the income increases of China and Southeast Asian countries have led to the rapid growth of footwear production and consumption in Asia. However, while advanced countries still include footwear business as one of their growth engines, Korea regard it as stagnant or diminishing. However, beyond the category of simple manufacturing, footwear industry involves the integration of highly functional products, parts manufacturing, and marketing business, and includes expertise in the fields of design, materials, and epidemiology. The strengthening of the shoe industry is an important potential driver of the overall economy. The strengthened competiveness of the footwear industry will play an important role in the overall economic growth. Crowdsourcing is an approach that encourages the participation of specific communities or unspecified masses in a company’s production, service, or problem-solving processes to increase efficiency. To this end, this paper suggests the crowdsourcing platform model built through the integration of footwear design and IT for the ultimate enhancement of the competitiveness of the Korean footwear industry. Following this paper, a study about the practical development, application, and active use of such platform needs to be conducted. One limitation of this study is that the platform is yet to be developed or applied. Future research should focus on developing an actual platform and further studies in its application and vitalization