Hybrid power management system using fuel cells and batteries

In the future, hybrid power management systems using fuel cells (FCs) and batteries will be used as the driving power systems of ships. These systems consist of an FC, a converter, an inverter, and a battery. In general, an FC provides steady-state energy; a battery provides the dynamic energy in the start state of a ship for enabling a smooth operation, and provides or absorbs the peak or dynamic power when the load varies and the FC cannot respond immediately. The FC voltage range is very wide and depends on the load; Therefore, the FC cannot directly connect to the inverter. In this paper, we propose a power management strategy and design process involving a unidirectional converter, a bidirectional converter, and an inverter, considering the ship’s operating conditions and the power conditions of the FC and the battery. The presented experimental results were verified through a simulation

Double resonance of Raman transitions in a degenerate Fermi gas

We measure momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of $^{173}$Yb atoms for a wide range of magnetic fields, where the atoms are irradiated by a pair of counterpropagating Raman laser beams as in the conventional spin-orbit coupling scheme. Double resonance of first- and second-order Raman transitions occurs at a certain magnetic field and the spectrum exhibits a doublet splitting for high laser intensities. The measured spectral splitting is quantitatively accounted for by the Autler-Townes effect. We show that our measurement results are consistent with the spinful band structure of a Fermi gas in the spatially oscillating effective magnetic field generated by the Raman laser fields.Comment: 7 pages, 6 figure

Relationship between chronic exposure to ambient air pollution and mental health in Korean adult cancer survivors and the general population

Background Although a significant association between air pollution and mental health has been identified, few studies have addressed this relationship based on cancer diagnosis. This study investigated whether associations between long-term air pollution and mental health conditions differ based on whether the individual has been diagnosed with cancer. Methods Nationally representative data were used and a total of 38,101 adults were included in the analyses. We assessed mental health factors such as perceived stress, depressive symptoms, and suicidal ideation, and analyzed the associations between these factors and individuals’ annual average exposure to air pollutants, including particulate matter with an aerodynamic diameter ≤ 10 μm (PM10), nitrogen dioxide, sulfur dioxide, and carbon monoxide. Results Compared with the general population, PM10 exposure in cancer survivors predicted a higher risk of depressive symptoms (odds ratio [OR] =1.34; 95% confidence interval [CI] = 1.06–1.69) and suicidal ideation (OR = 1.29; 95% CI = 1.01–1.64). Notably, the statistically significant relationship between PM10 exposure and suicidal ideation in cancer survivors disappeared after further adjustment for depressive symptoms (p = 0.3103). This pattern was also observed in the result of propensity score-matched analysis for comparison between cancer survivors and the general population. Conclusions This study provides the first evidence that cancer survivors with depressive symptoms may be more susceptible to suicidal ideation in the context of persistent PM10 exposure.This research was funded by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (grant no. 2018R1D1A1A09083190, 2021R1F1A1060847 and 2019R1A2C1004966). This research was also funded by the Education and Research Encouragement Fund of Seoul National University Hospital. The funding bodies played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript

CHARACTERIZATION OF THERMOMECHANICAL PULP MADE FROM PINE TREES INFECTED WITH NEMATODES

Pine wilt is a lethal disease caused by the nematode Bursaphelenchus xylophilus. It causes tree death by blocking water and nutrient uptake in pine trees. Pine trees infected by these nematodes are used as fertilizer or fuel for thermal power plants, but their utilization is still only about 37%. To increase the utilization of the infected trees, this study investigated whether the shredded wood chips prepared from them could be used as raw materials for manufacturing thermomechanical pulp (TMP) and chemithermomechanical pulp (CTMP). TMP and CTMP prepared from the infected pine chips showed fewer pitch contents and better strength properties than those made from domestic pine. In conclusion, if the nematode-infected pine was used as raw materials for manufacturing TMP and CTMP, it is expected that it would contribute to the diversification of raw materials along with a high-temperature insecticidal effect. Keywords: Pine wilt, nematode disease, thermomechanical pulp, chemithermomechanical pulp, pulp strength, insecticidal effect &nbsp

COMPARISON OF THE EFFECT OF TMP PITCH CONTROL AGENTS WITH DIFFERENT MECHANISMS

The pitch contained in thermomechanical pulp negatively affects paper quality, pulp, and the papermaking process. Serious pitch and stickies problems may occur in paper recycling processes. In this study, the effects of chemicals used to control the pitch in the TMP(Themomechanical Pulp) rocess were compared. The method used to analyze the pitch-control effect was to perform image analysis after using a reagent that selectively stains only the hydrophobic pitch. Three different mechanisms, namely fixation, detackification, and dispersion, were applied to solve the pitch problem from TMP. All the control agents were effective in pitch control, and, in particular, the agents related to fixation and dispersion were found to be more effective in reducing the number and area of tacky particles per unit area in sheets and white water. However, for the detackifiers and the dispersants, but not for the fixatives, it was difficult to clearly distinguish the difference of the pitch control effects according to the change in the amount of these agents through image analysis after staining

Kinematic aspects of trunk motion and gender effect in normal adults

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to analyze kinematic trunk motion data in normal adults and to investigate gender effect.</p> <p>Methods</p> <p>Kinematic trunk motion data were obtained for 20 healthy subjects (11 men and 9 women; age from 21 to 40 years) during walking a 9 m long lane at a self selected speed, namely, motions in the sagittal (tilt), coronal (obliquity), and transverse (rotation) planes, which were all expressed as motions in global (relative to the ground) and those in pelvic reference frame (relative to pelvis), i.e., tilt (G), obliquity (G), rotation (G), tilt (P), obliquity (P), rotation (P).</p> <p>Results</p> <p>Range of tilt (G), obliquity (G) and rotation (G) showed smaller motion than that of tilt (P), obliquity (P) and rotation (P), respectively. When genders were compared, female trunks showed a 5 degree more extended posture during gait than male trunks (p = 0.002), which appeared to be caused by different lumbar lordosis. Ranges of coronal and transverse plane motion appeared to be correlated. In gait cycle, the trunk motion appeared to counterbalance the lower extremity during swing phase in sagittal plane, and to reduce the angular velocity toward the contralateral side immediate before the contralateral heel strike in the coronal plane.</p> <p>Conclusions</p> <p>Men and women showed different lumbar lordosis during normal gait, which might be partly responsible for the different prevalence of lumbar diseases between genders. However, this needs further investigation.</p

Vertical ridge augmentation feasibility using unfixed collagen membranes and particulate bone substitutes: A 1- to 7-year retrospective single-cohort observational study

AIM To determine whether vertical ridge augmentation (VRA) can be obtained through guided bone regeneration (GBR) using exclusively resorbable collagen membranes and particulate bone substitutes without additional stabilization. MATERIALS AND METHODS This study retrospectively examined 22 participants who underwent VRA with staged or simultaneous implant placement. The vertical defects of all participants were filled with particulate bone substitutes and covered with resorbable collagen membranes. The augmented sites were stabilized with unfixed collagen membranes and the flap without any additional fixation. The augmented tissue height was assessed using cone-beam computed tomography at baseline, immediately after surgery, and at annual follow-ups. RESULTS The vertical bone gain of the 22 augmented sites amounted to 6.48 ± 2.19 mm (mean ± SD) immediately after surgery and 5.78 ± 1.72 mm at 1- to 7-year follow-up. Of the 22 augmented sites, 18 exhibited changes of less than 1 mm, while the other 4 showed changes of greater than 1 mm. Histological observation of three representative cases revealed new bone apposition on the remaining material. CONCLUSION The present findings indicate that GBR procedures using exclusively collagen membranes and particulate biomaterials without any additional fixation are feasible options for VRA