Autor: Thakur, A - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Assessment of metal hazard taking hair as an indicator of trace element exposure to workers in occupational environment
Ocena zagrozenia zatruciem metalami na podstawie analizy wlosow jako wskaznika wystawienia robotnikow na dzialanie pierwiastkow sladowych w srodowisku pracy
Autorzy:: Mehra, R
Thakur, A.S.
Powiązania:: https://bibliotekanauki.pl/articles/14765.pdf
Data publikacji:: 2010
Wydawca:: Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Tematy:: metal hazard
hair analysis
hazard indicator
trace element
element exposure
worker
occupational environment
health hazard
lead
calcium
magnesium
chromium
manganese
iron
nickel
copper
zinc
human body
mental stress
Opis:: The use of biological tissues as diagnostic tools of trace element level for recognising the disease status of an exposed human population is an important area of investigation. Quantitative analysis of 10 trace elements viz lead, calcium, magnesium, chromium, manganese, iron, nickel, copper, and zinc in the human body was performed using hair as biopsy material. In the present investigation, workers in a roadways workshop, locomotive workshop and Pb battery units were included as subjects. Head hair samples were collected from the nape region of the skull. Subsequent to sampling of hair, a questionnaire recommended by the World Health Organization was filled in order to obtain details about the subjects regarding occupation, duration of exposure, medical history, etc. Concentration of elements in hair was determined using an atomic absorption spectrophotometer. Workers under mental stress were treated as cases and workers without any symptoms of mental stress were chosen as controls. Significant difference in concentration of lead, calcium, magnesium, manganese, nickel, copper and zinc was found in hair of subjects with mental stress than those of controls. Concentration of chromium and iron was found higher in hair of subjects with mental stress but this difference was not significant with respect to controls.
Ważnym obszarem badań jest wykorzystywanie tkanek biologicznych do określania zawartości pierwiastków śladowych w celu diagnozowania chorób wśród populacji narażonych na skażenie środowiskowe. Analizowano zawartość 10 pierwiastków śladowych, m.in. ołowiu, wapnia, magnezu, chromu, manganu, żelaza, niklu, miedzi oraz cynku, w ciele ludzkim na podstawie włosów pobranych od robotników z warsztatów drogowych, kolejowych oraz mających do czynienia z akumulatorami zawierającymi rtęć. Próbki włosów pobrano z okolicy potylicznej czaszki. Po pobraniu próbek włosów, uczestniczący w badaniu wypełnili ankiety Oświatowej Organizacji Zdrowia, których celem było zebranie szczegółowych danych dotyczących miejsca pracy, czasu trwania ekspozycji na czynniki ryzyka, historii przebytych chorób, itp. Zawartość pierwiastków we włosach określono za pomocą spektrofotometru absorpcji atomowej. Robotnicy doświadczający stresu psychicznego zostali ujęci jako przypadki chorobowe, natomiast nie przejawiający objawów napięcia zostali potraktowani jako przypadki kontrolne. Stwierdzono istotne różnice w zawartości ołowiu, wapnia, magnezu, manganu, niklu, miedzi i cynku we włosach osób z objawami napięcia psychicznego w porównaniu z włosami pobranymi od osób bez takich symptomów. Zawartość chromu i żelaza we włosach osób z objawami stresu była także wyższa, ale różnice nie były istotne w porównaniu z kontrolą.
Źródło:: Journal of Elementology; 2010, 15, 4; 671-678
1644-2296
Pojawia się w:: Journal of Elementology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Text mining approach to analyse the relation between obesity and breast cancer data
Autorzy:: Kumar, A.
Thakur, P.
Gupta, K.
Pal, A.
Powiązania:: https://bibliotekanauki.pl/articles/10908.pdf
Data publikacji:: 2015
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:: Biomedical research needs to leverage and exploit large amount of information reported in scientific publication. Literature data collected from publications has to be managed to extract information, transforms into an understandable structure using text mining approaches. Text mining refers to the process of deriving high-quality information from text by finding relationships between entities which do not show direct associations. Therefore, as an example of this approach, we present the link between two diseases i.e. breast cancer and obesity.Obesity is known to be associated with cancer mortality, but little is known about the link between lifetime changes in BMI of obese person and cancer mortality in both males and females. In this article, literature data for obesity and breast cancer was obtained using PubMed database and then methodologies which employs groups of common genes and keywords with their frequency of occurrence in the data were used, aimed to establish relation between obesity and breast cancer visualized using Pi-charts and bar graphs. From the data analysis, we obtained 1 gene which showed the link between both the diseases and validated using statistical analysis and disease-connect web server. We also proposed 8 common higher frequency keywords which could be used for indexing while searching the literature for obesity and breast cancer in combination.
Źródło:: International Letters of Natural Sciences; 2015, 44
2300-9675
Pojawia się w:: International Letters of Natural Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A study of bearing capacity of skirted octagonal footings resting on different sands
Autorzy:: Thakur, A.
Dutta, R.K.
Powiązania:: https://bibliotekanauki.pl/articles/2175811.pdf
Data publikacji:: 2021
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: bearing capacity
sands
octagonal footing
singly skirted (SS)
doubly skirted (DS)
nośność
piaski
stopa fundamentowa ośmiokątna
Opis:: Purpose: After a thorough study of literature it is concluded that the studies related to unskirted/skirted octagonal footings on sand have not yet been investigated. Thus, this paper presents a numerical analysis to assess the ultimate bearing capacity of the unskirted, unskirted-embedded, singly and doubly skirted octagonal footings resting on different sands (S1, S2, and S3). The length of skirt and depth of the embedded footing were varied from 0.0B to 1.5B. Design/methodology/approach: The numerical square and octagonal footing with singly and doubly skirted footing models were developed using Plaxis 3D software. Findings: The results of the doubly skirted octagonal footings ultimate bearing capacity were marginally higher in comparison to the singly skirted footing at all normalised skirt depths as well as for all sands up to a Ds/B ratio 0.25 beyond which the increase in the ultimate bearing capacity in case of doubly skirted footing was appreciable. Research limitations/implications: The results presented in this paper were based on numerical analysis. However, for the actual footings the soil placement and compaction, details of skirt construction and the stress level will be different from the numerical analysis. Further investigations using full-scale numerical models simulating field size footings were recommended to generalize the results. Originality/value: No such study on singly and doubly skirted octagonal shaped footings were conducted so far. Hence, an attempt was made in this article to predict the bearing capacity of those footings using Plaxis 3D.
Źródło:: Archives of Materials Science and Engineering; 2021, 107, 1; 21--31
1897-2764
Pojawia się w:: Archives of Materials Science and Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Study of bearing capacity of skirted irregular pentagonal footings on different sands
Autorzy:: Thakur, A
Dutta, R. K.
Powiązania:: https://bibliotekanauki.pl/articles/1818797.pdf
Data publikacji:: 2021
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: bearing capacity
sands
friction angle
pentagonal footing
singly skirted
doubly skirted
nośność
piaski
kąt tarcia
Opis:: Purpose: The paper presents an experimental and numerical study to evaluate the bearing capacity of unskirted, singly and doubly skirted irregular pentagonal footings on different sands (S1, S2, S3) at a relative density of 30 %. The skirt depth of the footing was varied from 0.0B to 1.5B (B is the width of the square footing). Design/methodology/approach: The experimental and numerical study of the singly and doubly skirted irregular pentagonal footing resting on sands was modelled in a test tank and Plaxis 3D software respectively. Findings: The results of this study reveal that the bearing capacity was higher for the skirted irregular pentagonal footings on sand S3 followed by sand S2 and S1. The lowest percentage improvement for the singly skirted footing on sand S3 was 18.51% at a Ds/B = 0.25 whereas the highest improvement was 90.81% at a Ds/B = 1.50 for the singly skirted footing on sand S2. The highest percentage improvement for the doubly skirted footing on sand S2 was 95.13% at a Ds/B = 1.5 whereas the lowest improvement was 23.70% at a Ds/B = 0.25 the doubly skirted footing on sand S3. The results further revealed that the numerically obtained bearing capacity was marginally higher in comparison to the one obtained experimentally for the footings on all sands. Further, the experimental results validated the results obtained numerically with an average deviation of 8%. The percentage improvement in the bearing capacity was higher for the irregular pentagonal footing resting on sand S2 in comparison to sand S3 and S1. The settlement response of the irregular pentagonal footings is unchanged by increasing the number of elements beyond 7700. Both the experimental and numerical studies revealed a linear elastic behaviour at Ds = 0.5B, while the experimentally obtained pressure-settlement ratio plot shows a clear failure at Ds= 1B and 1.5B. Research limitations/implications: The results presented in this paper were based on the experimental and numerical study conducted on small scale model footings. However, for the actual footings, further study is recommended using full-scale field size footings to generalize the results. Originality/value: No experimental and numerical studies on singly and doubly skirted irregular pentagonal footings were conducted so far. Hence, an attempt was made in this article to predict the bearing capacity of these footings experimentally and using Plaxis 3D respectively.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2021, 105, 1; 5--17
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Prediction of flexural strength of FRC pavements by soft computing techniques
Autorzy:: Kimteta, A.
Thakur, M.S.
Sihag, P.
Upadhya, A.
Sharma, N.
Powiązania:: https://bibliotekanauki.pl/articles/24200582.pdf
Data publikacji:: 2022
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: flexural strength
fibre reinforced concrete
artificial neural network
random forest
random tree
M5P based model
wytrzymałość na zginanie
beton zbrojony włóknami
sztuczna sieć neuronowa
las losowy
drzewo losowe
model oparty na M5P
Opis:: Purpose: The mechanical characteristics of concrete used in rigid pavements can be improved by using fibre-reinforced concrete. The purpose of the study was to predict the flexural strength of the fibre-reinforced concrete for ten input variables i.e., cement, fine aggregate, coarse aggregate, water, superplasticizer/high range water reducer, glass fibre, polypropylene fibre, steel fibres, length and diameter of fibre and further to perform the sensitivity analysis to determine the most sensitive input variable which affects the flexural strength of the said fibre-reinforced concrete. Design/methodology/approach: The data used in the study was acquired from the published literature to create the soft computing modes. Four soft computing techniques i.e., Artificial neural networks (ANN), Random forests (RF), Random trees RT), and M5P, were applied to predict the flexural strength of fibre-reinforced concrete for rigid pavement using ten significant input variables as stated in the ‘purpose’. The most performing algorithm was determined after evaluating the applied models on the threshold of five statistical indices, i.e., the coefficient of correlation, mean absolute error, root mean square error, relative absolute error, and root relative squared error. The sensitivity analysis for most sensitive input variable was performed with out-performing model, i.e., ANN. Findings: The testing stage findings show that the Artificial neural networks model outperformed other applicable models, having the highest coefficient of correlation (0.9408), the lowest mean absolute error (0.8292), and the lowest root mean squared error (1.1285). Furthermore, the sensitivity analysis was performed using the artificial neural networks model. The results demonstrate that polypropylene fibre-reinforced concrete significantly influences the prediction of the flexural strength of fibre-reinforced concrete. Research limitations/implications: Large datasets may enhance machine learning technique performance. Originality/value: The article's novelty is that the most suitable model amongst the four applied techniques has been identified, which gives far better accuracy in predicting flexural strength.
Źródło:: Archives of Materials Science and Engineering; 2022, 117, 1; 13--24
1897-2764
Pojawia się w:: Archives of Materials Science and Engineering
Dostawca treści:: Biblioteka Nauki

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