• 제목/요약/키워드: Standard work type

검색결과 286건 처리시간 0.037초

Evaluation of a New Workplace Protection Factor―Measuring Method for Filtering Facepiece Respirator

  • Sun, Chenchen;Thelen, Christoph;Sanz, Iris Sancho;Wittmann, Andreas
    • Safety and Health at Work
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    • 제11권1호
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    • pp.61-70
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    • 2020
  • Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-CompanionTM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-CompanionTM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-CompanionTM) and the data detected by the flame photometer (R2 = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

Development and validation of a non-linear k-ε model for flow over a full-scale building

  • Wright, N.G.;Easom, G.J.;Hoxey, R.J.
    • Wind and Structures
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    • 제4권3호
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    • pp.177-196
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    • 2001
  • At present the most popular turbulence models used for engineering solutions to flow problems are the $k-{\varepsilon}$ and Reynolds stress models. The shortcoming of these models based on the isotropic eddy viscosity concept and Reynolds averaging in flow fields of the type found in the field of Wind Engineering are well documented. In view of these shortcomings this paper presents the implementation of a non-linear model and its evaluation for flow around a building. Tests were undertaken using the classical bluff body shape, a surface mounted cube, with orientations both normal and skewed at $45^{\circ}$ to the incident wind. Full-scale investigations have been undertaken at the Silsoe Research Institute with a 6 m surface mounted cube and a fetch of roughness height equal to 0.01 m. All tests were originally undertaken for a number of turbulence models including the standard, RNG and MMK $k-{\varepsilon}$ models and the differential stress model. The sensitivity of the CFD results to a number of solver parameters was tested. The accuracy of the turbulence model used was deduced by comparison to the full-scale predicted roof and wake recirculation zone lengths. Mean values of the predicted pressure coefficients were used to further validate the turbulence models. Preliminary comparisons have also been made with available published experimental and large eddy simulation data. Initial investigations suggested that a suitable turbulence model should be able to model the anisotropy of turbulent flow such as the Reynolds stress model whilst maintaining the ease of use and computational stability of the two equations models. Therefore development work concentrated on non-linear quadratic and cubic expansions of the Boussinesq eddy viscosity assumption. Comparisons of these with models based on an isotropic assumption are presented along with comparisons with measured data.

전기도금법에 의해 전착된 BixTey 박막의 전기 및 열전 특성 (Thermoelectric/electrical characterization of electrodeposited BixTey thin films)

  • 유인준;이규환;김양도;임재홍
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2012년도 춘계학술발표회 논문집
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    • pp.308-308
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    • 2012
  • Electrodeposition of thermoelectric materials, including binary and ternary compounds, have been attracting attentions, because its many advantages including cost-effectiveness, rapid deposition rate, and ease of control their microstructure and crystallinity by adjusting electrodeposition parameters. In this work, $Bi_xTe_y$ films were potentiostatically electrodeposited using Au/Ni(80/20 nm)/Si substrate as the working electrode in solutions consisting of 10mM $TeO_2$ and 1M $HNO_3$ where $Bi(NO_3)_3$ was varied from 2.5 to 10 mM. Prior to electrodeposition potentiostatically, linear sweep voltammograms (LSV) were acquired with a standard three-electrode cell. The $Bi_xTe_y$ films deposited using the electrolyte containing low Bi ions shows p-type conductivity, which might be attributed by the large incorporation of Te phases. Near stoichiometric $Bi_2Te_3$ thin films were obtained from electrolytes containing 5mM $Bi(NO_3)_3$. This film shows the maximum Seebeck coefficient of $-100.3{\pm}12.7{\mu}V/K$. As the increase of Bi ions in electrolytes decreases the Seebeck coefficient and resistivity. The maximum power factor of $336.2{\mu}W/m{\cdot}K^2$ was obtained from the film deposited using the solution of 7.5mM $Bi(NO_3)_3$.

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저전력 LiDAR 시스템을 위한 Adaptive Convolution Filter에 기반한 3D 공간 구성 (Adaptive Convolution Filter-Based 3D Plane Reconstruction for Low-Power LiDAR Sensor Systems)

  • 정태원;박대진
    • 한국정보통신학회논문지
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    • 제25권10호
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    • pp.1416-1426
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    • 2021
  • Scanning 타입 다채널 LiDAR 센서의 경우 수신되는 신호의 세기의 차이에 의한 walk error라는 거리 오차가 발생할 수 있다. 이러한 오차는 다수의 LiDAR 센서를 기반으로 주변 환경을 스캐닝할 경우 같은 물체에 대해 서로 다른 거리 값을 출력하게 한다. 다수의 LiDAR 센서를 이용하여 전방향 스캐닝할 경우, 센서의 시야각이 겹치는 구간에서 발생하는 walk error를 최소화하기 위해 외부 시스템 상에서 센서의 각 채널에 대한 convolution을 수행하고 오차를 최소화하고자 한다. 약 6×6 m 환경의 중앙에 4개의 LiDAR 센서들을 배치하고 주변 환경을 스캐닝 하였으며, 필터링을 적용한 결과, 거리 오차를 평균 0.5125m에서 0.16m까지 약 68% 개선할 수 있었으며, 표준 편차는 평균 0.0591에서 0.030675까지 약 48% 개선할 수 있었다.

Reconstruction of the Korean Asbestos Job Exposure Matrix

  • Kang, Dongmug;Jung, Saemi;Kim, Yun-Ji;Kim, Juyoung;Choi, Sangjun;Kim, Se Yeong;Kim, Youngki
    • Safety and Health at Work
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    • 제12권1호
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    • pp.74-95
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    • 2021
  • Background: A job-exposure matrix (JEM) is an important surrogate indicator to evaluate past exposure levels. Although a Korean asbestos JEM has been constructed previously, this JEM includes only a few industrial and occupational groups. This study aimed to reconstruct the JEM by integrating the latest organized data to improve its utility. Methods: We used recent Korean standard industry and occupation codes and extracted 36 articles from a systematic literature review to initiate the reconstruction of the previous Korean asbestos JEM. The resulting data consisted of 141 combinations of industrial and occupational groups. Data from the Netherlands's JEM were also reviewed and categorized into 70 industrial and 117 occupational groups by matching with the Korean data. We also utilized Germany's data, which consisted of 10 industrial and 14 occupational groups. Results: The reconstructed Korean asbestos JEM had 141 combinations of industries and occupations. The time periods are from the 1980s to the 2000s in 10-year intervals. Most of the data were distributed between the 1990s and the 2000s. Occupations with high exposure to asbestos included knitting and weaving machine operators, automobile mechanics or assemblers, ship mechanics or assemblers, mineral ore and stone products processing mechanics, and metal casting machine operators or mold makers. Conclusions: The reconstructed Korean asbestos JEM has expanded the type and duration of the occupational groups of the previous JEM and can serve as an important reference tool for evaluating asbestos exposure and designing compensation and prevention policies in Korea.

Calibration of cylindrical NaI(Tl) gamma-ray detector intended for truncated conical radioactive source

  • Badawi, Mohamed S.;Thabet, Abouzeid A.
    • Nuclear Engineering and Technology
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    • 제54권4호
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    • pp.1421-1430
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    • 2022
  • The computation of the solid angle and the detector efficiency is considering to be one of the most important factors during the measuring process for the radioactivity, especially the cylindrical γ-ray NaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health, the gamma-ray radiation detectors grow to be the main essential instruments in radiation protection sector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiency of the γ-ray spectrometry setup is established. The formulas are suitable for any type of source-to-detector shape and can be valuable to determine the full-energy peak and the total efficiencies and P/T ratio of cylindrical γ-ray NaI(Tl) detector setup concerning the truncated conical radioactive source. This methodology is based on estimate the path length of γ-ray radiation inside the detector active medium, inside the source itself, and the self-attenuation correction factors, which typically use to correct the sample attenuation of the original geometry source. The calculations can be completed in general by using extra reasonable and complicate analytical and numerical techniques than the standard models; especially the effective solid angle, and the detector efficiency have to be calculated in case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be used for the straight calculations of the γ-ray detector efficiency after the computation of improvement that need in the case of γ-γ coincidence summing (CS). The (NSM) confirmation of the development created by the efficiency transfer method has been achieved by comparing the results of the measuring truncated conical radioactive source with certified nuclide activities with the γ-ray NaI(Tl) detector, and a good agreement was obtained after corrections of (CS). The methodology can be unlimited to find the theoretical efficiencies and modifications equivalent to any geometry by essential sufficiently the physical selective considered situation.

The Role of Smart Technologies in Training Future Specialists

  • Oksana, Popovych;Rostislav, Motsyk;Iryna, Mozul;Karina, Fedchenko;Andrii, Zhbanchyk;Olena, Terenko;Oleksandr, Kuchai
    • International Journal of Computer Science & Network Security
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    • 제22권12호
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    • pp.153-159
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    • 2022
  • The article discusses the use of smart technologies in the training of future specialists. Today, learning using smart technologies is becoming a new educational standard, where information is presented in a logical sequence, computer training systems have powerful functions for the educational process. The functions of smart technologies are highlighted. It is noted that smart technologies are successfully used in the field of education and professional training. The concept of "smart education" is characterized. Smart education is an educational paradigm that underlies a new type of education system. The implementation of the smart education paradigm is aimed at the process of obtaining competencies and competencies for flexible and adapted interaction with the social, economic and technological environment. Smart education should ensure that the benefits of the global information society can be used to meet educational needs and interests. A special place is occupied by computer-based educational multimedia systems that allow you to deepen your knowledge, reduce the duration of training, and increase the number of students per teacher. The main principles of smart education are highlighted. Improving the efficiency of training in a modern higher education institution is impossible without the introduction of smart technologies in the organization of the educational process.

Fractal dimension analysis as an easy computational approach to improve breast cancer histopathological diagnosis

  • Lucas Glaucio da Silva;Waleska Rayanne Sizinia da Silva Monteiro;Tiago Medeiros de Aguiar Moreira;Maria Aparecida Esteves Rabelo;Emílio Augusto Campos Pereira de Assis;Gustavo Torres de Souza
    • Applied Microscopy
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    • 제51권
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    • pp.6.1-6.9
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    • 2021
  • Histopathology is a well-established standard diagnosis employed for the majority of malignancies, including breast cancer. Nevertheless, despite training and standardization, it is considered operator-dependent and errors are still a concern. Fractal dimension analysis is a computational image processing technique that allows assessing the degree of complexity in patterns. We aimed here at providing a robust and easily attainable method for introducing computer-assisted techniques to histopathology laboratories. Slides from two databases were used: A) Breast Cancer Histopathological; and B) Grand Challenge on Breast Cancer Histology. Set A contained 2480 images from 24 patients with benign alterations, and 5429 images from 58 patients with breast cancer. Set B comprised 100 images of each type: normal tissue, benign alterations, in situ carcinoma, and invasive carcinoma. All images were analyzed with the FracLac algorithm in the ImageJ computational environment to yield the box count fractal dimension (Db) results. Images on set A on 40x magnification were statistically different (p = 0.0003), whereas images on 400x did not present differences in their means. On set B, the mean Db values presented promising statistical differences when comparing. Normal and/or benign images to in situ and/or invasive carcinoma (all p < 0.0001). Interestingly, there was no difference when comparing normal tissue to benign alterations. These data corroborate with previous work in which fractal analysis allowed differentiating malignancies. Computer-aided diagnosis algorithms may beneficiate from using Db data; specific Db cut-off values may yield ~ 99% specificity in diagnosing breast cancer. Furthermore, the fact that it allows assessing tissue complexity, this tool may be used to understand the progression of the histological alterations in cancer.

Assessing Neurobehavioral Alterations Among E-waste Recycling Workers in Hong Kong

  • Gengze Liao;Feng Wang;Shaoyou Lu;Yanny Hoi Kuen Yu;Victoria H. Arrandale;Alan Hoi-shou Chan;Lap Ah Tse
    • Safety and Health at Work
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    • 제15권1호
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    • pp.9-16
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    • 2024
  • Background: E-waste workers in Hong Kong are handling an unprecedented amount of e-waste, which contains various neurotoxic chemicals. However, no study has been conducted to evaluate the neurological health status of e-waste workers in Hong Kong. This study aimed to evaluate the prevalence of neurobehavioral alterations and to identify the vulnerable groups among Hong Kong e-waste workers. Methods: We recruited 109 Hong Kong e-waste workers from June 2021 to September 2022. Participants completed standard questionnaires and wore a GENEActiv accelerometer for seven days. Pittsburgh Sleep Quality Index and Questionnaire 16/18 (Q16/18) were used to assess subjective neurobehavioral alterations. The GENEActiv data generated objective sleep and circadian rhythm variables. Workers were grouped based on job designation and entity type according to the presumed hazardous level. Unconditional logistic regression models measured the associations of occupational characteristics with neurobehavioral alterations after adjusting for confounders. Results: While dismantlers/repairers and the workers in entities not funded by the government were more likely to suffer from neurotoxic symptoms in Q18 (adjusted odds ratio: 3.18 [1.18-9.39] and 2.77 [1.10-7.46], respectively), the workers from self-sustained recycling facilities also have poor performances in circadian rhythm. Results also showed that the dismantlers/repairers working in entities not funded by the government had the highest risk of neurotoxic symptoms compared to the lowest-risk group (i.e., workers in government-funded companies with other job designations). Conclusion: This timely and valuable study emphasizes the importance of improving the working conditions for high-risk e-waste workers, especially the dismantlers or repairers working in facilities not funded by the government.

담수산 새우 Macrobrachium japonicum (De Haan)의 Zoea 유생기에 출현하는 동일영기군 속의 개체변이체에 대한 형태학적 고찰 (MORPHOLOGICAL VIEW ON BIG INDIVIDUALS APPEARED IN THE SAME AGE GROUP OF ZOEA LARVA, MACROBRACHIUM JAPONICUM (DE HAAN))

  • 권진수
    • 한국수산과학회지
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    • 제7권3호
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    • pp.126-144
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    • 1974
  • 1. 사육수조에서 교모 포난시킨 친하로부터 부화된 유생을 순환식 이중수조내에서 수온 $26\pm0.3^{\circ}C$, Chlorioity $6.21-6.45\%$ Cl., pH $8.\~8.1$, 조도 3,000 lux의 조건하에서 Artemia salina nauplius를 먹이로 급여하여 사육했다. 2. 동일영기군에서 출현하는 개체변이체(숙성이)와 표준형개체 사이의 형태적 차이를 비교하여 숙성이의 출현영기와 관련이 있는 제4영기로부터 제9영기의 각 부속지의 발생과정을 관찰한 결과, 본종에 있어서도 개체성장의 변이에 의한 숙성이가 출현하기 쉬운 영기(제5영기와 제7영기)가 존재하며 이 현상이 일어나게 되는 원인은 섭이요인과 관련이 큰 것으로 보인다. 3. 동일영기군의 숙성이를 외형적인 형태학적 면으로 기관의 분화정도로써 표준형의 개체와 비교 조사한 결과 동일영기군에서 출현하는 숙성이의 각 부여기관은 부분적으로는 영기가 발전된 개체의 특징도 구비하지만 또 다른 면으로는 그 영기의 표준형의 특징도 구비하고 있다. 그래서, 각 영기의 특징은 개체의 크기에 관계없이 동일영기의 특징을 부분적으로나마 명확히 보유하고 있었다. 한편 본종에 있어서의 개체변이체는 한 영기를 완전히 비약성약하여 그 다음 영기로 이행하는 것이 아니고 부속기관의 분화속도가 부분적으로 이시성을 나타낼 따름이므로 완전한 skipping 현상은 관찰할 수 없었다. 4. 유생의 부속기의 발생분화는 일과적으로 개체변이가 크지만 환경요인의 변화에 따라 안정성을 가지는 부분과 이와 반대로 변이의 감수성이 큰 두 부분으로 나눌 수 있으며 따라서 한 개체내의 각 부속기의 분화, 발생은 부위에 따라 이시성을 가지고 있는 것 같다. 5. 각 영기의 노정은 종래와 같이 탈피후의 1개체의 전체 부속기의 변화된 정도에 따라 정할 것이아니라 전술한 환경요인의 변동에 대해서 극히 안정성을 띄는 부속기관을 지표로 하여 정하는 것이 타당할 것 같다.

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