• Title/Summary/Keyword: mechanical life

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Study of the Calendar Aging of Lithium-Ion Batteries Using SEI Growth Models (SEI 성장 모델을 이용한 리튬 이온 배터리의 캘린더 노화 연구)

  • Dong Hyup Jeon;Byungman Chae;Sangwoo Lee
    • Applied Chemistry for Engineering
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    • v.35 no.1
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    • pp.48-53
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    • 2024
  • We predicted the calendar aging and long-term lifetime of lithium-ion batteries using an electrochemical-based SEI growth model. Numerical simulation was carried out employing the four different long-term SEI growth models (i.e., solvent diffusion limited model, electron migration limited model, Li-interstitial diffusion limited model, reaction limited model), and we calculated the capacity fade and loss of lithium inventory during calendar aging. The result showed that the electron migration limited model and Li-interstitial diffusion limited model showed lower capacity fade, while the solvent diffusion limited model and reaction limited model reached 80% of capacity fade within 10 years. During calendar aging, the lower storage temperature showed less capacity fade due to the hindrance of SEI growth rate. During cycling, the higher C-rate showed a shorter life cycle; however, the differences were not significant.

Unexpected Restart Failure of Durable Left Ventricular Assist Devices: A Report of Two Cases

  • Hyo Won Seo;Ga Hee Jeong;Sung Min Kim;Minjung Bak;Darae Kim;Jin-Oh Choi;Kiick Sung;Yang Hyun Cho
    • Journal of Chest Surgery
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    • v.57 no.3
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    • pp.315-318
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    • 2024
  • The HeartWare Ventricular Assist Device (HVAD) was widely used for mechanical circulatory support in patients with end-stage heart failure. However, there have been reports of a critical issue with HVAD pumps failing to restart, or experiencing delays in restarting, after being stopped. This case report describes 2 instances of HVAD failure-to-restart during heart transplantation surgery and routine outpatient care. Despite multiple attempts to restart the pump using various controllers and extensions, the HVAD failed to restart, triggering a hazard alarm for pump stoppage. In one case, the patient survived after receiving a heart transplantation, while in the other, the patient died immediately following the controller exchange. These cases highlight the rare but life-threatening complication of HVAD failure-to-restart, underscoring the importance of awareness among clinicians, patients, and caregivers, and adherence to the manufacturer's guidelines and recommendations for HVAD management.

A Study on detection of missing person using DRONE and AI (드론과 인공지능을 활용한 실종자 탐색에 관한 연구)

  • Kyoung-Mok Kim;Ho-beom Jeon;Geon-Seon Lim
    • Journal of the Health Care and Life Science
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    • v.10 no.2
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    • pp.361-367
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    • 2022
  • This study provides several methods to minimize dead zone and to detect missing person using combined DRONE and AI especially called 4 th Industrial Revolution. That is composed of image acquisition for a person who is in needed of support. The procedure is DRONE that is made of image acquisition and transfer system. after that can be shown GPS information. Currently representative AI algorithm is YOLO (You Only Look Once) that can be adopted to find manikin or real image by learning with dataset. The output was reached in reliable and efficient results. As the trends of DRONE is expanded widely that will provide various roll. This paper was composed of three parts. the first is DRONE specification, the second is the definition of AI and procedures, the third is the methods of image acquisition using DRONE, the last is the future of DRONE with AI.

The Effects of Mechanical Horseback-Riding Exercise on Lumbar Flexibility (승마기구 운동이 허리 유연성에 미치는 영향)

  • Si-Kyoung Lee
    • Journal of the Health Care and Life Science
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    • v.11 no.1
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    • pp.149-153
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    • 2023
  • This study conducted an eight-week equestrian exercise for 20 adults aged 20 or older to find out the effect of equestrian exercise on the flexibility of the human body.As a result of the experiment, the range of flexion-tension in the waist joint motion increased from an average of 120.2° to an average of 132.5° before the experiment, and the range of lateral bending increased from an average of 65.8° to an average of 67.3°. In the Sit and reach Test, it increased from 2.94 mm to 4.97 mm before the experiment. It was found that the range of motion of the joint increased during flexion and extension of the waist, and as the range of lateral bending increased, the flexibility of the human body increased. To confirm this, a flexibility test was conducted, and I believe that riding equipment exercise is a physiotherapy intervention that prevents back pain and increases flexibility in the human body, I would like to suggest that it can be used to promote health not only for patients with diseases such as back pain but also for the healthy general public.

Kinetics study of photo-degradation of poly(Vinyl Chloride) films in presence of organotin(IV) complex derivatives

  • Alaa Mohammed;Mohammed Kadhom;Marwa Fadhil;Alhamzah D. Hameed;Ahmed Imad;Ahmed Alamiery;Muna Bufaroosha;Rahimi M. Yusop;Ali Jawad;Emad Yousif
    • Analytical Science and Technology
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    • v.37 no.4
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    • pp.251-260
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    • 2024
  • As polymers became very important in our lives, their negative impact on general health and the environment raised a serious issue. Here, enhancing their life term is presented as a compromise solution between the need and harm. In the study, six PVC films, the plain and five filled with improvers, underwent radiation exposure for 300 hours at room temperature to investigate their photodegradation rates. The modified films were embedded with organotin(IV) complex derivatives (Ph3SnL, Ph2SnL2, Bu3SnL, Bu2SnL2, and Me2SnL2 (where L is levofloxacin)), and their effectiveness was evaluated. The PVC films were compared before and after exposure to various tests including UV-Vis spectroscopy, gel content analysis, theoretical calculations, and EDX microscopy. Findings indicated that the presence of organotin(IV) complex derivatives, particularly Ph3SnL, notably decreased UV light absorbance and the amount of gel content in PVC sheets in comparison to untreated PVC. Furthermore, EDX analysis showed that the PVC-Ph3SnL blend exposed to radiation exhibited the highest chlorine content, reaching 30 %. This blend demonstrated superior efficacy in stabilizing the polymeric materials.

Cultural Memory and Reification of Memory Constructed by <Solaris>(Andrei Tarkovsky, 1972) (안드레이 타르콥스키의 <솔라리스>에 구성된 문화적 기억과 기억의 물화)

  • Kang Seungmook
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.5
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    • pp.71-76
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    • 2024
  • In modern capitalist society, where the influence of electronic and mechanical technology on the human memory construction process is gradually expanding, academic interest in the cultural construction and reification of memory is also spreading. This study attempted to explore the way cultural memory and the reification of memory are constructed and their implications by analyzing Andrei Tarkovsky's <Solaris>, which delved into the way human memory is constructed based on scientific thinking. On 'Solaris', which is both a planet and an ocean, memories were materialized by taxidermy or fossilization of love and even the truth of life and death. This can be said to be the result of director Andrei Tarkovsky's reflection on the fact that human memory can be anchored to something due to a specific event, and that reificated memory is not the actual memory, but remains only as a trace or trace of the memory.

Nursing Students' Ethical Attitudes toward DNR: The Impact of Educational Experience

  • Miok Kim;Hyun-A Nam
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.9
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    • pp.187-196
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    • 2024
  • This study investigated the ethical attitudes towards Do Not Resuscitate (DNR) among nursing college students. Data were collected from September to November 2022, involving 209 students in Jeonbuk Province. Analysis was done using SPSS WIN 25.0 with descriptive statistics and the χ2-test. Students generally agreed with respecting patient wishes, providing accurate information, and adhering to DNR guidelines. They supported treatment upon guardian request and maintaining aseptic principles for DNR patients. They showed neutral attitudes towards discontinuing mechanical ventilation upon family request, using all means to prolong life for patients with no chance of survival, the primary physician's DNR decision, etc. There was often opposition to the decline in medical team interest after DNR declaration. Significant differences based on DNR education experience were found regarding the use of all treatments for terminally ill patients (p=.028) and the need to advise if a co-worker treats a DNR patient without aseptic procedures (p=.014). Education on DNR situations and procedures is essential for accurate knowledge and high ethical competence.

Impacts of Ocean Currents on the South Indian Ocean Extratropical Storm Track through the Relative Wind Effect

  • Hyodae Seo;Hajoon Song;Larry W. O'Neill;Matthew R. Mazloff;Bruce D. Cornuelle
    • Journal of Climate Change Research
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    • v.34 no.22
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    • pp.9093-9113
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    • 2021
  • This study examines the role of the relative wind (RW) effect (wind relative to ocean current) in the regional ocean circulation and extratropical storm track in the south Indian Ocean. Comparison of two high-resolution regional coupled model simulations with and without the RW effect reveals that the most conspicuous ocean circulation response is the significant weakening of the overly energetic anticyclonic standing eddy off Port Elizabeth, South Africa, a biased feature ascribed to upstream retroflection of the Agulhas Current (AC). This opens a pathway through which the AC transports the warm and salty water mass from the subtropics, yielding marked increases in sea surface temperature (SST), upward turbulent heat flux (THF), and meridional SST gradient in the Agulhas retroflection region. These thermodynamic and dynamic changes are accompanied by the robust strengthening of the local low-tropospheric baroclinicity and the baroclinic wave activity in the atmosphere. Examination of the composite life cycle of synoptic-scale storms subjected to the high-THF events indicates a robust strengthening of the extratropical storms far downstream. Energetics calculations for the atmosphere suggest that the baroclinic energy conversion from the basic flow is the chief source of increased eddy available potential energy, which is subsequently converted to eddy kinetic energy, providing for the growth of transient baroclinic waves. Overall, the results suggest that the mechanical and thermal air-sea interactions are inherently and inextricably linked together to substantially influence the extratropical storm tracks in the south Indian Ocean.

Measurement of Porcine Aortic and Pulmonary Valve Geometry and Design for Implantable Tissue Valve (돼지 대동맥, 폐동맥의 근위부 기하학적 구조 측정을 통한 판막 구조 수치의 계량화와 판막 도안에 관한 연구)

  • Park, Sung-Joon;Kim, Yong-Jin;Nam, Jin-Hae;Kim, Soo-Hwan;Lee, Chang-Ha;Lim, Hong-Gook
    • Journal of Chest Surgery
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    • v.43 no.6
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    • pp.602-613
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    • 2010
  • Background: As life expectancy has been increased, the cardiac valve disease has been increased. In past, mechanical valve for valve replacement surgery was used widely, but it has many weaknesses, such as hemorrhage, teratogenic effect caused by warfarin, acute mechanical failure, taking warfarin during life, etc. So, the tissue valve is used widely and researches for durability of tissue valve are in progress. Tissue valves being used are all imported in Korea, and there is a lack of information on its geometry and design. So, we studied the geometry of porcine aortic and pulmonary valve, and tried to suggest theoretical basis for making the aortic and pulmonary valve. Material and Method: We harvested aortic and pulmonary valves of 25 pigs and measured the geometry of valve at fresh and glutaraldehyde (GA) fixed state. In each group, we measured the diameter of the base, diameter of commissure, valve height, commissural height, etc. Also, for making implantable porcine and bovine pericardial valve, we designed the valve stent form, thickness, height, and leaflet size, form, thickness by different size of valve. Result: The aortic and pulmonary valve geometry and ratio were measured in each group. The right coronary cusp of aortic valve and right facing cusp of pulmonary valve was bigger than other cusps and non coronary cusp was smaller than others (RCC: NCC : LCC=1 : 0.88 : 1). Valve height was correlated to the leaflet size. We designed the outer diameter of stented porcine aortic valve from 19 mm to 33 mm and designed stent height and width, using previous measured ratio of each structure, stent thickness, working thickness (for making valve). Also, we designed the size of stent and form for stented bovine pericardial valve, considering diameter of valve, leaflet length, height and leaflet minimum coaptation area. Conclusion: By measuring of 25 pig's aortic and pulmonary valve geometry and ratio, we can make theoretical basis for making implantable stented porcine valve and bovine pericardial valve in various size. After making implantable valve using these data, it is necessary to do in vivo and in vitro researches, furthermore.

Effect of Soluble Chitosan on the Quality of Paeksulgis (백설기의 품질특성에 미치는 수용성 키토산의 영향)

  • 박찬성;정현숙
    • Food Science and Preservation
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    • v.9 no.3
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    • pp.321-326
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    • 2002
  • Paeksulkis(Korean rice cake) containing 0-0.5% chitosan were prepared for test the quality of microbiological, mechanical and sensory characteristics. The pH of Paeksulkis was 5.65 without chitosan and that was about 7.0 with 0.05-0.5% level of chitosan. In Hunter's color values of Paeksulkis of control, the lightness(L) was 84.28, redness(a) was -1.56 and yellowness(b) was 7.68. The lightness(L), redness(a) and yellowness(b) were increased with increasing concentration of chitosan in Paeksulkis. In mechanical characteristics of Paeksulkis, cohesiveness and springiness were the highest in control group while strength, hardness, gumminess and brittlenes were higher in chitosan added group than control group. In sensory evaluation of Pasksulkis, control group obtained the highest score in color, texture, after swallowing and overall quality(p<0.05) but chitosan added group obtained higher scores in moisture than control(p<0.05). Total bacterial counts(TBC) of Paeksulgis immediately before storage were 4.2∼9.2$\times$10$^2$CFU/g and those of control increased for 2 weeks, reached at 7.4$\times$10$\^$5/ CFU/g and then decreased about 1 log cycle for 2 weeks during storage at 5$\^{C}$. TBC of Paeksulgis added 0.3∼0.5% of chitosan were 2 log cycles lower than that of control at the end of storage at 5$\^{C}$. TBC of Pasksulgis control increased to 10$\^$8/ CFU/g during storage at 20$\^{C}$ but that of 0.5% chitosan added group was 1 log cycle lower than control at the end of storage. Shelf-life extension of Paeksulkis by chitosan was more effective during storage at 5$\^{C}$ than at 20$\^{C}$.