Design and Control of Multi-Plate MR Clutch Featuring Friction and Magnetic Field Control Modes.

A magnetorheological (MR) multi-plate clutch was proposed with both mechanical friction mode and magnetic field control modes. The magnetic field control mode was based on an MR fluid coupler that changed its viscous properties according to the density of an applied magnetic field. This mode was used in the early stage of clutch operation to reduce the impact of friction between the disc and plate, and eliminate to the extent possible the difference in their relative speeds when contacting each other in later stages. Once the rotational speed difference between the disc and plate was reduced, the clutch was operated in mechanical friction mode by compressing the friction surfaces together. A torque modeling equation was then derived for each mode based on the Bingham model of the MR fluid, and the transmission torque of the proposed multi-plate clutch was derived using these equations as well as magnetic field analysis results obtained using ANSYS Maxwell. A multi-plate MR clutch was then fabricated, and its torque transmission characteristics were evaluated in the magnetic field control and mechanical friction modes. The results confirmed that the model-based torque calculations were consistent with the observed transmission torque. Finally, control algorithms for mechanical friction only and mixed mechanical friction/magnetic field control torque tracking of the proposed MR multi-plate clutch were designed, and their performances were evaluated when applying unit step command, half-sine-wave command, and rotational speed changes. The results indicated that the torque tracking control was performed smoothly, demonstrating the advantages of the proposed clutch.

Design and Analysis of a Hybrid Annular Radial Magnetorheological Damper for Semi-Active In-Wheel Motor Suspension.

In this study, a novel hybrid annular radial magnetorheological damper (HARMRD) is proposed to improve the ride comfort of an electric vehicle (EV) powered by an in-wheel motor (IWM). The model primarily comprises annular-radial ducts in series with permanent magnets. Mathematical models representing the governing motions are formulated, followed by finite element analysis of the HARMRD to investigate the distribution of the magnetic field density and intensity of the magnetorheological (MR) fluid in both the annular and radial ducts. The optimized model generates a damping force of 87.3-445.7 N at the off-state (zero input current) with the excitation velocity ranging between 0 and 0.25 m/s. By contrast, the generated damping force varies from 3386.4 N to 3753.9 N at an input current of 1.5 A with the same velocity range as the off state. The damping forces obtained using the proposed model are 31.4% and 19.2% higher for the off-field and on-field states, respectively, compared with those of the conventional annular radial MR damper. The efficiency of the proposed model is evaluated by adopting two different vehicles: a conventional vehicle powered by an engine and an EV powered by an IWM. The simulation results demonstrate that the proposed HARMRD along with the skyhook controller significantly improves both the ride comfort and road-holding capability for both types of vehicles.

Methodology for Sound Quality Analysis of Motors for Automotive Interior Parts through Subjective Evaluation.

With the development of autonomous vehicles, activities in the indoor spaces of autonomous vehicles are diversifying. Therefore, as the operating range of the interior parts increases, the occupant becomes sensitive to the operating noise of autonomous vehicles. Therefore, to reduce operating noise, it is necessary to analyze the causal relationship between the mechanical/electrical noise characteristics of the motor and sound quality. In this paper, we propose a methodology to analyze the relationship between the noise frequency components and the sound quality of small motors used in automobile interior parts. Two types of motors were selected for this study, and noise measurements and analyses were performed by applying the design proposed in this study. Subjective sound quality evaluations were conducted using the 12 pairs of adjectives extracted from the survey. The results suggest that subjective sound quality evaluation scores should be converted to Z-scores to ensure the reliability of the statistical analysis. In addition, we present a critical sound quality value that can be used as a criterion for determining whether the sound quality is positive (good quality) or negative (bad quality). Sound quality regression models explain the causal relationship between rotational frequency components of the motor and subjective sound quality characteristics. Thus, a method for analyzing the effect of the rotational frequency component of the motor on the sound quality is presented, which suggests that it can be used as basic research data to improve the noise performance of the motor.

A New Fracture Detection Algorithm of Low Amplitude Acoustic Emission Signal Based on Kalman Filter-Ripple Voltage.

In this study, an acoustic emission (AE) sensor was utilized to predict fractures that occur in a product during the sheet metal forming process. An AE activity was analyzed, presuming that AE occurs when plastic deformation and fracturing of metallic materials occur. For the analysis, a threshold voltage is set to distinguish the AE signal from the ripple voltage signal and noise. If the amplitude of the AE signal is small, it is difficult to distinguish the AE signal from the ripple voltage signal and the noise signal. Hence, there is a limitation in predicting fractures using the AE sensor. To overcome this limitation, the Kalman filter was used in this study to remove the ripple voltage signal and noise signal and then analyze the activity. However, it was difficult to filter out the ripple voltage signal using a conventional low-pass filter or Kalman filter because the ripple voltage signal is a high-frequency component governed by the switch-mode of the power supply. Therefore, a Kalman filter that has a low Kalman gain was designed to extract only the ripple voltage signal. Based on the KF-RV algorithm, the measured ripple voltage and noise signal were reduced by 97.3% on average. Subsequently, the AE signal was extracted appropriately using the difference between the measured value and the extracted ripple voltage signal. The activity of the extracted AE signal was analyzed using the ring-down count among various AE parameters to determine if there was a fracture in the test specimen.

Dynamic Analysis of Sphere-Like Iron Particles Based Magnetorheological Damper for Waveform-Generating Test System.

In this study, a new double pulse waveform-generating test system with an integrated magnetorheological (MR) damper is proposed. Since the total shear stress of MR fluid can be varied according to the shape of particles, sphere-like iron particles-based MR fluid is filled into the MR damper. The test system consists of a velocity generator, three masses (impact, test, and dummy), a spring, and an MR damper. To tune the double pulse waveform profile, a damping force model is constructed to determine the fundamental parameters of the simulator. Then, the first and second shock waveform profiles are analyzed to solve the governing equation of motions representing the damping force and velocity. The mathematical model of the MR damper is formulated and applied to a simulator with a graphical user interface programmed using MATLAB. The effectiveness of the proposed simulator-featuring controllable MR damper is demonstrated by comparing the simulation and experimental results.

Hospital Outbreaks of Middle East Respiratory Syndrome, Daejeon, South Korea, 2015.

From May through July 2015, a total of 26 cases of Middle East Respiratory Syndrome were reported from 2 hospitals in Daejeon, South Korea, including 1 index case and 25 new cases. We examined the epidemiologic features of these cases and found an estimated median incubation period of 6.1 days (8.8 days in hospital A and 4.6 days in hospital B). The overall attack rate was 3.7% (4.7% in hospital A and 3.0% in hospital B), and the attack rates among inpatients and caregivers in the same ward were 12.3% and 22.5%, respectively. The overall case-fatality rate was 44.0% (28.6% in hospital A and 63.6% in hospital B). The use of cohort quarantine may have played a role in preventing community spread, but additional transmission occurred among members of the hospital cohort quarantined together. Caregivers may have contributed in part to the transmission.

The increasing incidence of paranasal organizing hematoma: a 20-year experience of 23 cases at a single center.

BACKGROUND AND OBJECTIVES: Sinonasal organized hematoma is a rare, benign disease that can be locally aggressive and may be mistaken for malignancy. Because of its rarity, the clinical characteristics are not well known. The aim of this study is to investigate the distinguishing features of organized hematoma with an emphasis on incidence change. MATERIALS AND METHODS: In this retrospective study, we reviewed the records of 23 patients with organized hematoma confirmed histopathologically among 5,378 patients who underwent endoscopic sinus surgery performed by a single surgeon from January 1995 to December 2014 at a tertiary care center. Clinical symptoms, endoscopic photography, computed tomography, and operative findings were reviewed. We also reviewed the relevant literature. Age, sex, site, origin subsite and histopathology were investigated. A statistical review was performed using R 3.1.2 to examine incidence change. RESULTS: The most common complaint was frequent epistaxis and nasal obstruction (52.1%). Of the 23 patients, eight were women and 15 were men with an age range of 18 to 75 years. (mean 38.9 years). Nine of these hematomas occurred on the right side and 14 on the left side. The predominant occurrence site was the antrum (65%), followed by the septum (17.3%), inferior turbinate (8%), and ethmoid sinus (8%). The incidence steadily increased over 20 years. CONCLUSION: Investigation of the clinical characteristics and incidence change of organized hematoma can provide useful information. Through analysis of the 23 cases in our study, the age distribution was found to be bimodal and the incidence of organizing hematoma was observed to steadily increase. Clinicians should be aware of these characteristics to avoid misdiagnoses of malignant tumors.

Mumps Presenting as a Parotid Abscess.

Parotid abscess is an uncommon condition in infants. It is frequently associated with prematurity, prolonged gavage feeding, and dehydration. Mumps is a viral disease caused by paramyxovirus. It frequently involves the parotid gland and is only rarely found in the pancreas, testis, or brain. The authors describe a rare case of a 10-month-old infant with mumps who developed the classical manifestations of unilateral acute parotitis progressing to formation of a parotid abscess that responded to 2 rounds of surgical drainage and antibiotic therapy.

Evaluation of the Ejection Pressure for Tracking Internal Cracks during Compaction in Bilayer Tablet Formulations Using Experimental and Finite Element Methods.

This study aimed to evaluate the ejection pressure and the correlation of the findings with the occurrence of internal cracks within bilayer tablets (BLTs) consisting of metformin HCl (MF) and evogliptin tartrate (EG). Then, the mechanism of tablet failure was provided by the finite element method (FEM). The ejection pressure and the difference in diameter depending on MAIN-P were evaluated to understand the correlation between ejection pressure and change in the BLT internal structure. The ejection pressure and the difference in diameter increased as the MAIN-P increased, then steeply decreased from 350 MPa to 375 MPa of MAIN-P, despite there being no pattern in compaction breaking force and porosity. The mechanical integrity at the BLT interface was weakened by internal cracks, reducing ejection pressure. The stress distribution analysis during the compression revealed that crack formation caused by entrapped air located at the center of the BLT interface may not propagate due to concentrated stress, which promotes a tight bond at the edge of the BLT. Furthermore, complete delamination can occur in the ejection process due to localized and intensive shear stresses at the BLT interface. These findings indicate that the mechanisms of internal cracking and delamination were successfully confirmed by FEM simulation. Moreover, measuring ejection pressure before BLT manufacturing can prevent invisible tablet cracks without damaging the tablets.

Predictive Performance Neutrophil-to-Lymphocyte Ratio of Acute Tonsillitis with Deep Neck Space Infection in Adult Patients.

The aim of this study was to examine the neutrophil-to-lymphocyte ratio (NLR) in patients diagnosed with a deep neck infection (DNI) to identify helpful indicators for the initial differential diagnosis. This study was conducted as a single-center, retrospective cohort study that utilized data from the electronic medical records of patients who visited the emergency department in a tertiary university hospital between February 2018 and April 2022. The study enrolled patients aged ≥18 years who were diagnosed with tonsillitis with or without DNI during the study period. The NLR of patients without DNI was 6.1 ± 5.03, and the NLR of patients with acute tonsillitis with DNI was 8.0 ± 5.67, showing significant differences. The rate of admission in the general wards (GWs) and ICUs was significantly higher in patients with DNI, and the length of hospital stay was also significantly longer in patients with DNI. Older age, male, lower body temperature, C-reactive protein, and NLR were significant independent risk factors for DNI in patients with tonsillitis. The cutoff value for predicting DNI in patients with body temperature <37.5 was 3.09. The NLR of patients with tonsillitis, especially those with normal body temperature, can be used to predict their prognosis.

Effect of Dietary Supplementation of Fermented Pine Needle Extract on Productive Performance, Egg Quality, and Serum Lipid Parameters in Laying Hens.

This study aimed to investigate the supplemental effects of fermented pine (Pinus densiflora) needle extract (FPNE) in laying hen diets on productive performance, egg quality, and serum lipid metabolites. A total of 108 40-week-old Hy-line brown laying hens were randomly assigned to one of the three dietary treatment groups: (1) basal diet + 0 mL FPNE/kg diet (CON), (2) basal diet + 2.5 mL FPNE/kg diet (T1), or (3) basal diet + 5 mL FPNE/kg diet (T2) for 6 weeks. Each group consisted of four replicates of nine hens each. Feed and water provided ad libitum. Results showed that dietary supplementation of FPNE increased egg production percentage (linear, p < 0.01 and quadratic, p < 0.05), egg mass (linear, p < 0.05), and feed intake (linear, p < 0.05) during the entire experimental period. In addition, dietary inclusion of FPNE significantly increased the eggshell color (linear, p < 0.01), egg yolk color (quadratic, p < 0.01), and eggshell breaking strength (linear, p < 0.05 and quadratic, p < 0.05) while the Haugh unit decreased (quadratic, p < 0.05). However, serum lipid profile did not differ among the dietary treatments (p > 0.05). Notably, antioxidant activity of egg yolk was improved by significantly decreasing the malondialdehyde content in egg yolks after 6 weeks of storage (linear, p < 0.001 and quadratic, p < 0.05). In summary, dietary inclusion of FPNE could improve laying performance and the antioxidant capacity of eggs.

Effect of dietary supplementation of a phytogenic blend containing Schisandra chinensis, Pinus densiflora, and Allium tuberosum on productivity, egg quality, and health parameters in laying hens.

OBJECTIVE: This study was conducted to investigate the supplementary effect of a phytogenic blend (SPA: a mixture containing fermented Schisandra chinensis pomace, fermented Pinus densiflora needle extract, and Allium tuberosum powder in the ratio of 2:2:1) on egg production, egg quality, blood constituents, and visceral organs in laying hens. METHODS: A total of 135 Hy-line brown laying hens (48-wk-old) were randomly allocated to three dietary treatments with 5 replicates of 9 hens. The control group (CON) was fed a basal diet (no exogenous SPA addition) and the experimental groups were fed the basal diet containing SPA at the level of 0.1% and 0.3% for 6 weeks. RESULTS: The feed intake was significantly improved in SPA supplemented groups as compared with the control (p<0.05). However, egg production, daily egg mass, and feed conversion ratio were not different among the dietary treatments (p>0.05). For egg quality traits, only Haugh unit (HU) was significantly improved in SPA (0.3%) (p<0.05) as compared with other groups. However, HU was not affected during 4-wk of storage at 18°C among the dietary treatments (p>0.05). Furthermore, SPA supplementation did not affect the blood biochemical constituents except for the phosphate content, which was significantly higher in SPA groups than the CON group (p<0.05). There were no significant differences in visceral organ characteristics and immune indicators (immunoglobulin A [IgA], IgG, and IgM) in SPA or CON groups. CONCLUSION: This study suggested that the supplementation of SPA may have beneficial effects on feed intake and egg quality in laying hens.

Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis.

Biportal endoscopic spinal surgery (BESS) is a minimally invasive spinal surgery, which is basically similar to microscopic spinal surgery in terms of the use of floating technique and technically similar to conventional percutaneous endoscopic spinal surgery in terms of the use of endoscopic or arthroscopic instruments. Using two independent portals (viewing and working) and maintaining a certain distance from the bony and neural structures allow closer access to the target lesion through a panoramic view by free handling of the scope and instruments rather than through a fixed view by docking into the Kambin's triangle. Minimally invasive surgery allows for reduced dissection and inevitable muscle injury, preserving stability and reducing risks of restabilization. The purpose of fusion surgery is the same as that of the three surgical techniques stated above. Its wider range of view helps to overcome limitations of conventional endoscopic spinal surgery and to supplement the weak points of microscopic spinal surgery, such as limited working space in a tubular retractor and difficulty in accessing the contralateral area. This technique provides an alternative to unilateral or bilateral decompression of lumbar central spinal stenosis, foraminal stenosis, low-grade spondylolisthesis, and adjacent segment degeneration. Early clinical outcomes are promising despite potential for complications, such as dural tearing and postoperative epidural hematoma, similar to other procedures. Merits of BESS include decreased postoperative infection rate due to continuous irrigation throughout the procedure and decreased need for fusion surgery for one- or two-level lumbar stenosis by wide sublaminar and foraminal decompression with minimal sacrifice of stabilizing structures.

Material Characterization of Hardening Soft Sponge Featuring MR Fluid and Application of 6-DOF MR Haptic Master for Robot-Assisted Surgery.

In this work, the material characterization of hardening magneto-rheological (MR) sponge is analyzed and a robot-assisted surgery system integrated with a 6-degrees-of-freedom (DOF) haptic master and slave root is constructed. As a first step, the viscoelastic property of MR sponge is experimentally analyzed. Based on the viscoelastic property and controllability, a MR sponge which can mimic the several reaction force characteristics of human-like organs is devised and manufactured. Secondly, a slave robot corresponding to the degree of the haptic master is manufactured and integrated with the master. In order to manipulate the robot motion by the master, the kinematic analysis of the master and slave robots is performed. Subsequently, a simple robot cutting surgery system which is manipulated by the haptic master and MR sponge is established. It is then demonstrated from this system that using both MR devices can provide more accurate cutting surgery than the case using the haptic master only.

Changes in Oral Vowel Sounds and Hyoid Bone Movement After Thyroidectomy.

OBJECTIVES: Voice and speech alterations after total thyroidectomy may be associated with other extralaryngeal factors, such as neck muscle dysfunction and neck scar contracture. We evaluated the acoustic characteristics of oral vowel sounds and changes in hyoid bone movement before and after thyroidectomy. METHODS: Twenty-nine female patients undergoing total thyroidectomy were included. Fundamental frequencies (Fo), formants and vowel space areas were evaluated before surgery and 7 days and 3 months after surgery to acoustically analyze the oral vowel sounds. Videofluoroscopic images were taken at the same times to evaluate hyoid bone movement. RESULTS: The Fo levels of seven vowels decreased significantly after surgery. The vowel formant changes the F1 of vowel /[e]/ decreased significantly from baseline at 3 months postoperatively, and the F3 of vowel /[i]/ decreased significantly from baseline 7 days postoperatively. The change in the vowel space area was not observed. The Y coordinate of the vowels /[i]/ and /[e]/ decreased significantly from baseline 7 days postoperatively due to changes in hyoid movement. CONCLUSION: The damage to the neck muscles after thyroidectomy changes in Fo, formant and hyoid bone position. These quantitative results could be used as basic data for voice management in patients who undergo thyroidectomy.

Z-lengthening of the Achilles tendon with transverse skin incision.

BACKGROUND: The risk of various complications after Achilles tendon lengthening is mainly related to the length of surgical exposure and the lengthening method. A comprehensive technique to minimize the complications is required. METHODS: The treatment of Achilles tendon tightness in 57 patients (95 ankles) were performed by using a short transverse incision on a skin crease of the heel and by Z-lengthening of the tendon. In the severe cases, two or three transverse incisions were required for greater lengthening of the tendon, and a serial cast or Ilizarov apparatus was applied for the gradual correction. The results of these 95 ankles were compared to those of 18 ankles, which underwent percutaneous sliding lengthening, and to the 19 ankles, which received Z-lengthening with a medial longitudinal incision. RESULTS: The functional and cosmetic satisfaction was achieved among those who underwent the tendon lengthening with the new technique. The mean American Orthopaedic Foot & Ankle Society (AOFAS) score improved from 56.1 to 81.8. The second operations to correct recurrence were performed in the two cerebral palsy patients. CONCLUSIONS: The new technique has a low rate of complications such as scarring, adhesion, total transection, excessive lengthening, and recurrence of shortening. The excellent cosmesis and the short operation time are the additional advantages.

Correlation between endobutton loop length and tunnel widening after hamstring anterior cruciate ligament reconstruction.

BACKGROUND: Previous reports have shown that graft fixation with the Endobutton is associated with tunnel widening because it provides distant fixation rather than aperture fixation. HYPOTHESIS: A longer loop of the Endobutton results in greater tunnel widening than a shorter loop. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 171 consecutive patients underwent hamstring anterior cruciate ligament (ACL) reconstruction fixed with the Endobutton. They were followed for a minimum of 2 years postoperatively. A 15-mm loop was used in 20 patients, a 20-mm loop in 53, a 25-mm loop in 58, and a >30-mm loop in 40. On anterior-posterior (AP) and lateral radiographs, the measured diameters of the femoral tunnel at 2 years after surgery were compared with the diameter of the reamer used at surgery. The measured diameter of the tibial tunnel at 2 years after surgery was compared with measurements taken on the immediate postoperative day. The center of the tibial tunnel and direction of the ACL graft were also measured. Postoperative knee stability was evaluated using the Lachman test, pivot-shift test, and KT-1000 arthrometer. Functional evaluations were performed using the Lysholm score and Tegner activity scale. All measurements were compared among the 4 groups according to the length of the Endobutton loop. RESULTS: The mean ± standard deviation (SD) diameter of the femoral tunnel increased by 50.7% ± 23.3% and 37.0% ± 18.8% on AP and lateral radiographs at 2 years after surgery, respectively. The mean ± SD diameter of the tibial tunnel increased by 40.8% ± 19.3% and 46.4% ± 22.6% on AP and lateral radiographs, respectively. No significant difference in tunnel widening was present according to the length of the Endobutton loop. There were no significant differences in the average center of the tibial tunnel or the average angle of the direction of the ACL graft among the 4 groups. There was no significant difference in Lachman test results, postoperative KT-1000 arthrometer side-to-side differences, Lysholm score, and Tegner activity scale score among the 4 groups. The group with a >30-mm loop showed a significant difference in the pivot-shift test than the other 3 groups (P = .023). CONCLUSION: A longer Endobutton loop did not result in greater tunnel widening than a shorter loop. Long fixation distance may not be associated with tunnel widening after hamstring ACL reconstructions.

All-inside repair for a root tear of the medial meniscus using a suture anchor.

BACKGROUND: There are no published articles reporting clinical outcomes after all-inside meniscal repair using a suture anchor for a medial meniscal root tear. PURPOSE: To evaluate the subjective and objective outcomes after repair of medial meniscal root tears. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Thirteen patients with a root tear of the medial meniscus underwent all-inside repair using a suture anchor. Postoperative evaluation of meniscal status was performed using physical examination criteria, specifically joint line tenderness, McMurray test, and follow-up magnetic resonance imaging (MRI). Functional evaluations were performed using Tegner activity level and Lysholm knee score. Follow-up MRI scans were obtained 6 months postoperatively to evaluate healing of the root tear and measure extrusion of the midbody of the medial meniscus. RESULTS: The average follow-up was 30.8 months (range, 24-40 months). No patients had joint line tenderness or effusion. No patients demonstrated a positive McMurray test result postoperatively. The preoperative mean Tegner activity level was 1.9 (range, 1-6), and the mean Lysholm score was 69.1 (range, 53-91). At last follow-up, the mean Tegner activity level was 3.9 (range, 2-6), and the mean Lysholm score was 90.3 (range, 75-100). Improvements in both the Tegner activity level and Lysholm score were statistically significant (P = .001 and P = .000, respectively). Follow-up MRI was performed in 10 patients. Five (50%) patients showed complete healing; 2 of these 5 patients showed complete healing with isointense signal of a normal meniscus, and 3 showed intermediate signal tissue at the previous tear site without any high signal cleft or ghost sign. Four (40%) patients showed partial healing, and 1 (10%) showed no healing. Mean extrusion of the midbody of the medial meniscus was 3.9 mm (range, 2.2-7.1 mm) preoperatively and 3.5 mm (range, 1.2-6.1 mm) postoperatively. Extrusion was not significantly decreased. CONCLUSION: This study demonstrated symptomatic improvement after meniscal root repair using a suture anchor. However, follow-up MRI scans did not show complete healing of all repaired root tears.