• Title/Summary/Keyword: surface state

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Geomorphic-characteristics of debris flow induced by typhoon "RUSA" in 2002 using Shalstab Model and Remote Sensing: case study in Macheon region near Jiri-Mountain (원격탐사와 수치 모형을 이용한 2002년 태풍 "루사"에 의해 발생한 토석류 발생지점특성: 지리산 마천면 지역을 사례로)

  • Kim, Minseok;Kim, Jin Kwan;Cho, Youngchan;Kim, Sukwoo
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.193-202
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    • 2011
  • Kompsat EOC-1 imagery, high resolution air-photo imagery and Shalstab model were used to analyze the geomorphic characteristics of the place of debris flow occurred by typhon "RUSA" in 2002, Macheon-Myen, Gyeongsang prefecture, Republic of Korea. On gully-head over 35 degree of slope angle, almost debris flow started, where slope angle is more than internal friction angle. The result simulated by Shalstab model presented larger vulnerable area to debris flow than the area where debris flow really occurred, this error would be attributed to the assumption for steady-state condition with full saturated surface. To predict the debris flow accurately, further study for rainfall and soil water flow will be needed.

Human Impacts on Urban Landscapes in North American Desert: A Case Study in the Phoenix, Arizona, USA (북아메리카 사막 지형에 미친 인류의 영향: 피닉스, 애리조나 지역을 사례로)

  • Jeong, Ara
    • Journal of The Geomorphological Association of Korea
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    • v.26 no.3
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    • pp.69-85
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    • 2019
  • Humans have been important driver to reconfigure the terrestrial surface of the Earth by altering its morphology and processes. The effect of human activities on the physical landscape, however, shows substantially uneven geographical patterns. Most of anthrogemorphoogical studies regarding human-induced denudation have focused on areas with a long history of human modifications such as humid landscapes, so the hypothesis is naturally a great human impact on landscapes. The effect of human activities on dryland Earth surfaces are far less commonly studied, although erosion is one of major concerns in arid and semi-arid region regarding land and water quality degradation. The urban metropolis of Phoenix, Arizona, USA provides an opportunity to explore the impact of the Anthropocene. The Phoenix metropolitan area rests on classic desert landforms, such as extensive pediments, alluvial fans and sand sheets. Human activities including cattle crazing, wildfire resulting from introduced grass species by human, and recent urbanization processes have impacted these classic desert landforms and altered geomorphic processes. The purpose of this paper, therefore, rests in examining Anthropocene in the geomorphology of the north-central Sonoran Desert. The objectives of this paper are: i) to understand the impact of the Anthropocene on the geomorphological processes and forms through field observations; ii) to quantify the magnitude of human impacts on landscape using a published two-decade long record of erosion dataset and natural background erosion dataset in submitted manuscript at the sprawling edge of the Phoenix metropolitan region; iii) to examine how geomorphic outcome can affect the sustainability of cities through the estimation of sediment yield under the condition of urban sprawl.

Mid- and Low-Latitude Earth Ionospheric Phenomena and Current Status of Research (중·저위도 지구 전리권 현상 및 연구 현황 )

  • Eojin Kim;Ki-nam Kim
    • Journal of Space Technology and Applications
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    • v.3 no.3
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    • pp.239-256
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    • 2023
  • The Earth's ionosphere is an area where part of the upper atmosphere is ionized and exists in a plasma state that affects radio waves. It is a field that has been studied for a long time as it directly affects real life in relation to communications. Depending on the altitude, it is divided into D, E, and F layers depending on the main ions that make up the electron density. The density of the neutral atmosphere is very large compared to the electron density, so it should be described as plasma taking that effect into account. It is an area where influences from outside the ionosphere are directly reflected, starting from the sun and extending to the earth's surface, and is a field that involves complex and diverse areas of research. In this paper, we explain the process by which the Earth's upper atmosphere is ionized to form the ionosphere and introduce the characteristics of the ionosphere at low and mid-latitudes. In addition, we introduce the research that domestic researchers have participated in related to the ionosphere to date and hope that it will be used to promote exchange in the field of ionospheric research in the future.

Testing and evaluation of the corrosion behavior of Aluminum/Alumina bulk composites fabricated via combined stir casting and APB process

  • Abdalkareem Jasim;Ghassan Fadhil Smaisim;Abduladheem Turki Jalil;Surendar Aravindhan;Abdullah Hasan Jabbar;Shaymaa Abed Hussein;Muneam Hussein Ali;Muataz S. Alhassan;Yasser Fakri Mustafa
    • Advances in materials Research
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    • v.12 no.4
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    • pp.263-271
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    • 2023
  • In this study, AA1060/Alumina composites were fabricated by combined stir casting and accumulative press bonding (APB). The APB process was repeated up to six press bonding steps at 300Ċ. As the novelty, potential dynamic polarization in 3.5Wt% NaCl solution was used to study the corrosion properties of these composites. The corrosion behavior of these samples was compared and studied with that of the annealed aluminum alloy 1060 and versus the number of APB steps. So, as a result of enhancing influence on the number of APB process, this experimental investigation showed a significant enhancement in the main electrochemical parameters and the inert character of the Alumina particles. Together with Reducing the active zones of the material surfaces could delay the corrosion process. Also, at higher number of steps, the corrosion resistance of composites improved. The sample produced after six number of steps had a low corrosion density in comparison with high corrosion density of annealed specimens. Also, the scanning electron microscopy (SEM), was used to study the corrosion surface of samples.

Synthesis and Analysis of the Impact of Partial Mercury Replacement with Lead on the Structural and Electrical Properties of the Hg1-xPbxBa2Ca2Cu3O8+δ Superconductor

  • Kareem Ali Jasim;Chaiar Abdeen Zaynel Saleh;Alyaa Hamid Ali Jassim
    • Korean Journal of Materials Research
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    • v.34 no.1
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    • pp.21-26
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    • 2024
  • In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

Thermal imaging and computer vision technologies for the enhancement of pig husbandry: a review

  • Md Nasim Reza;Md Razob Ali;Samsuzzaman;Md Shaha Nur Kabir;Md Rejaul Karim;Shahriar Ahmed;Hyunjin Kyoung;Gookhwan Kim;Sun-Ok Chung
    • Journal of Animal Science and Technology
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    • v.66 no.1
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    • pp.31-56
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    • 2024
  • Pig farming, a vital industry, necessitates proactive measures for early disease detection and crush symptom monitoring to ensure optimum pig health and safety. This review explores advanced thermal sensing technologies and computer vision-based thermal imaging techniques employed for pig disease and piglet crush symptom monitoring on pig farms. Infrared thermography (IRT) is a non-invasive and efficient technology for measuring pig body temperature, providing advantages such as non-destructive, long-distance, and high-sensitivity measurements. Unlike traditional methods, IRT offers a quick and labor-saving approach to acquiring physiological data impacted by environmental temperature, crucial for understanding pig body physiology and metabolism. IRT aids in early disease detection, respiratory health monitoring, and evaluating vaccination effectiveness. Challenges include body surface emissivity variations affecting measurement accuracy. Thermal imaging and deep learning algorithms are used for pig behavior recognition, with the dorsal plane effective for stress detection. Remote health monitoring through thermal imaging, deep learning, and wearable devices facilitates non-invasive assessment of pig health, minimizing medication use. Integration of advanced sensors, thermal imaging, and deep learning shows potential for disease detection and improvement in pig farming, but challenges and ethical considerations must be addressed for successful implementation. This review summarizes the state-of-the-art technologies used in the pig farming industry, including computer vision algorithms such as object detection, image segmentation, and deep learning techniques. It also discusses the benefits and limitations of IRT technology, providing an overview of the current research field. This study provides valuable insights for researchers and farmers regarding IRT application in pig production, highlighting notable approaches and the latest research findings in this field.

The luminescence properties of Eu3+ or Tb 3+ doped Lu2Gd1Ga2Al3O12 phosphors for X-ray imaging

  • M.J. Oh;Sudipta Saha;H.J. Kim
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4642-4646
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    • 2023
  • The Tb3+ or Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor were fabricated by funace at 1500 ℃ for 12 h using a solid state reaction. The XRD (X-ray diffraction_Panalytical X'Pert Pro) and FE-SEM (field emission scanning electron microscope) are measured to confirm the crystalline structure and surface morphology of the phosphor. The Tb3+-doped Lu2Gd1Ga2Al3O12 phosphor emits the lights in 470~650 nm wavelength range due to transitions from 5D4 to 7Fj. Therefore, it shows the green region in the CIE chromaticity diagram under both UV and X-rays excitations. The Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor emits the lights in 550~750 nm wavelength range because of 5Di to 7Fj. The emission is confirmed to be in the red region using the CIE chromaticity diagram. The Tb3+ or Eu3+-doped Lu2Gd1Ga2Al3O12 phosphor shows the characteristic f-f transition with a long decay time, which is about several milliseconds. They have the high efficiency of light emission for X-ray because of their high effective Z number (Zeff = 58.5) and density. Therefore, they are very much promising phosphors for X-ray imaging application in medical fields.

A computer vision-based approach for crack detection in ultra high performance concrete beams

  • Roya Solhmirzaei;Hadi Salehi;Venkatesh Kodur
    • Computers and Concrete
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    • v.33 no.4
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    • pp.341-348
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    • 2024
  • Ultra-high-performance concrete (UHPC) has received remarkable attentions in civil infrastructure due to its unique mechanical characteristics and durability. UHPC gains increasingly dominant in essential structural elements, while its unique properties pose challenges for traditional inspection methods, as damage may not always manifest visibly on the surface. As such, the need for robust inspection techniques for detecting cracks in UHPC members has become imperative as traditional methods often fall short in providing comprehensive and timely evaluations. In the era of artificial intelligence, computer vision has gained considerable interest as a powerful tool to enhance infrastructure condition assessment with image and video data collected from sensors, cameras, and unmanned aerial vehicles. This paper presents a computer vision-based approach employing deep learning to detect cracks in UHPC beams, with the aim of addressing the inherent limitations of traditional inspection methods. This work leverages computer vision to discern intricate patterns and anomalies. Particularly, a convolutional neural network architecture employing transfer learning is adopted to identify the presence of cracks in the beams. The proposed approach is evaluated with image data collected from full-scale experiments conducted on UHPC beams subjected to flexural and shear loadings. The results of this study indicate the applicability of computer vision and deep learning as intelligent methods to detect major and minor cracks and recognize various damage mechanisms in UHPC members with better efficiency compared to conventional monitoring methods. Findings from this work pave the way for the development of autonomous infrastructure health monitoring and condition assessment, ensuring early detection in response to evolving structural challenges. By leveraging computer vision, this paper contributes to usher in a new era of effectiveness in autonomous crack detection, enhancing the resilience and sustainability of UHPC civil infrastructure.

Understanding a Core Pilin of the Type IVa Pili of Acidithiobacillus thiooxidans, PilV

  • Araceli Hernandez-Sanchez;Edgar D. Paez-Perez;Elvia Alfaro-Saldana;Vanesa Olivares-Illana;J. Viridiana Garcia-Meza
    • Journal of Microbiology and Biotechnology
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    • v.34 no.3
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    • pp.525-537
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    • 2024
  • Pilins are protein subunits of pili. The pilins of type IV pili (T4P) in pathogenic bacteria are well characterized, but anything is known about the T4P proteins in acidophilic chemolithoautotrophic microorganisms such as the genus Acidithiobacillus. The interest in T4P of A. thiooxidans is because of their possible role in cell recruitment and bacterial aggregation on the surface of minerals during biooxidation of sulfide minerals. In this study we present a successful ad hoc methodology for the heterologous expression and purification of extracellular proteins such as the minor pilin PilV of the T4P of A. thiooxidans, a pilin exposed to extreme conditions of acidity and high oxidation-reduction potentials, and that interact with metal sulfides in an environment rich in dissolved minerals. Once obtained, the model structure of A. thiooxidans PilV revealed the core basic architecture of T4P pilins. Because of the acidophilic condition, we carried out in silico characterization of the protonation status of acidic and basic residues of PilV in order to calculate the ionization state at specific pH values and evaluated their pH stability. Further biophysical characterization was done using UV-visible and fluorescence spectroscopy and the results showed that PilV remains soluble and stable even after exposure to significant changes of pH. PilV has a unique amino acid composition that exhibits acid stability, with significant biotechnology implications such as biooxidation of sulfide minerals. The biophysics profiles of PilV open new paradigms about resilient proteins and stimulate the study of other pilins from extremophiles.

Performance Evaluation of Structure Strengthening Using Sprayed FRP Technique (분사식 FRP공법을 이용한 구조물 보강 성능평가)

  • Chang, Chun-Ho;Jang, Kwang-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.4 s.56
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    • pp.126-136
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    • 2009
  • The sprayed FRP strengthening technique is combining the Glass fiber and Polyester resin in open air and spraying randomly at concrete's surface with high-speed compressed air. Then it strengthens the structures with a new technique evaluated the structural performance. We applied it to concrete beam and tested for flexural strength, depended on Korea Standard(KS F 2408). Then based on the result of flexural strength, the properties were proposed that applying to structures. Based on the experiment, we have evaluated structural performance by the experiment. 1/5 scale prestressed concrete I-beam were made by Korean Highway's typical drawing in 1993. With these test results, 49.8% increased in flexural strength, improvement of the behavior of serviceability state, and strengthening was surely effective for controlling deflection and crack of structure. Consequently, it can be summarized that Sprayed FRP technique has prospect to improve the performance of structure.