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Tytuł:
Evaluation of modified hard fluors for biscuit making
Przydatność zmodyfikowanej mąki pochodzącej z twardej pszenicy do produkcji ciastek
Autorzy:
Damir, A.A.
Salem, A.
Mohamed, M.S.
Powiązania:
https://bibliotekanauki.pl/articles/10314.pdf
Data publikacji:
1976
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Opis:
Przeprowadzono próby modyfikacji mąki pochodzącej z pszenicy twardej w celu uzdatnienia jej jako surowca do produkcji ciastek. W tym celu do mąki mocnej dodawano w różnych stężeniach metadwusiarczyn sodu, siarczyn, skrobię oraz mąkę słabą z mąką słodową. Jako kryterium zmian jakościowych służyły wskaźniki reologiczne ciasta. Potrzebne zmiany jakościowe we właściwościach reologicznych uzyskano przez dodatek 228 mg/kg S₂O₅, 64 mg/kg SO₃, 5% skrobi lub 50% mąki słabej. Mieszanina 20% słodu i 64 mg/kg SO₃ powodowała zmiękczenie ciasta i wzrost jego rozciągliwości, co w efekcie dało najlepszy surowiec do otrzymywania ciastek o wysokiej jakości organoleptycznej. Zmiękczenie ciasta pod wpływem czynników redukujących i słodu powiązane było z ilością wolnych grup SH. Oprócz poprawy jakości uzyskano 27% wzrost objętości ciastek.
Źródło:
Acta Alimentaria Polonica; 1976, 02, 4
0137-1495
Pojawia się w:
Acta Alimentaria Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Back Muscle Activity in an Automobile Seat with a Lumbar Massage System
Autorzy:
Kolich, M.
Taboun, S. M.
Mohamed, A. I.
Powiązania:
https://bibliotekanauki.pl/articles/90384.pdf
Data publikacji:
2000
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
automotive seating
electromyography
low back pain
ból pleców
elektromiografia
masaż
Opis:
This investigation was conducted to determine the effects of a massaging lumbar support system on low back muscle activity. The apparatus included a luxury-level automobile seat, six 10-mm diameter bipolar surface electrodes, an amplifier, an anaiog-to-digital conversion board, data acquisition software, and a personal computer. Six experimental conditions, each involving a variation of massage time, were considered. The dependent variable was the change in the root mean square variation of the EMG signal. One minute of lumbar massage every 5 min was found to have a beneficial effect on low back muscle activity (as compared to no massage). This may prove to be an extremely important result in the quest to combat low back pain attributable to automobile seating.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2000, 6, 1; 113-128
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Factors affected the performance of fire clay refractory bricks
Czynniki wpływające na wytrzymałość cegieł z gliny ogniotrwałej
Autorzy:
Elngar, M. A. G.
Mohamed, F. M.
El-Bohy, S. A. H.
Sharaby, C. M.
Shalabi, M. E. H.
Powiązania:
https://bibliotekanauki.pl/articles/349655.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
wytrzymałość
kruszywo szamotowe
kaolin
szok termiczny
siła kompresji
refractory
grog
thermal shocks
compressive strength
Opis:
In this investigation some factors affected the performance of the fire clay refractory bricks such as size of grog, percentage of water added to the raw material, percentage of grog and temperature of firing were studied. The results showed that if the percentage of grog increased the shrinkage of bricks decreased, as well as density of bricks was increasing the porosity and water absorption also increased. Furthermore, with increasing of the added water to the raw material the porosity of the bricks increased and if water absorption increased, density decreased. The characteristics of raw material by such methods as x-ray and chemical analysis were also examined.
W pracy zbadano niektóre czynniki wpływające na wytrzymałość cegieł z gliny ogniotrwałej, tj. rozmiar kruszywa szamotowego, procent dodanej wody, zawartość procentowa kruszywa szamotowego, czy temperatura wypalania. Wyniki wskazały, że gdy zawartość procentowa kruszywa szamotowego zwiększyła się to kurczliwość cegieł malała. Analogicznie, gdy gęstość cegieł rosła, porowatość i absorpcja wody również rosła. Zwiększając ilość wody dodawanej do surowca, wywoływało się zwiększenie porowatości cegieł, zaś gdy absorpcja wody zwiększała się - gęstość materiału malała. Charakterystyka materiału za pomocą promieni X oraz analizy chemicznej została również przedstawiona.
Źródło:
Górnictwo i Geoinżynieria; 2009, 33, 4; 49-61
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of~Rf Plasma Nitrided Silicon Thin Films at Different Rf Plasma Processing Powers
Autorzy:
Mohamed, S.
Raaif, M.
Abd El-Rahman, A.
Shaaban, E.
Powiązania:
https://bibliotekanauki.pl/articles/1493713.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Dj
61.05.cp
73.61.-r
78.66.-w
Opis:
Nitrided surfaces and composition gradients in thin films exhibit interesting mechanical, electrical and optical properties. Therefore, silicon (Si) thin films were prepared by electron beam evaporation and nitrided by an inductively coupled rf plasma. The effects of successive plasma processing power on structural and optical properties as well as electrical resistivity were examined by different characterization techniques. The Si thin films were transformed gradually into nitrides compound thin films and the amount of nitrogen in the film increased with increasing the rf processing power. The Si nitrided films showed structural, optical and electrical properties that depend on the nitriding power. Increasing the rf plasma processing power caused amorphization, reduced the thickness, increased transmittance, increased resistivity and decreased the reflectance of the Si films. The electrical resistivity increased about eight orders of magnitude when the sample nitrided at 500 W. Different optical band gap were determined indicating the presence of different competing phases in the same film. The decrease in refractive index with plasma treatment power is attributed to the possible change in the bucking density as well as to the increase in the band gap.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 552-557
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic noses for monitoring benzene occupational exposure in biological samples of Egyptian workers
Autorzy:
Mohamed, Ehab I.
Khalil, Gihane I.
Abdel-Mageed, Samir M.
Bayoumi, Amani M.
Ramadan, Heba S.
Kotb, Metwally A.
Powiązania:
https://bibliotekanauki.pl/articles/2179801.pdf
Data publikacji:
2013-03-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
phenol
muconic acid
exhaled air
blood
urine
principal component analysis
Opis:
Objectives: Benzene is commonly emitted in several industries, leading to widespread environmental and occupational exposure hazards. While less toxic solvents have been substituted for benzene, it is still a component of petroleum products and is a trace impurity in industrial products resulting in continued higher occupational exposures in industrial settings in developing countries. Materials and Methods: We investigated the potential use of an electronic nose (e-nose) to monitor the headspace volatiles in biological samples from benzene-exposed Egyptian workers and non-exposed controls. The study population comprised 150 non-smoking male workers exposed to benzene and an equal number of matching non-exposed controls. We determined biomarkers of benzene used to estimate exposure and risk including: benzene in exhaled air and blood; and its urinary metabolites such as phenol and muconic acid using gas chromatography technique and a portable e-nose. Results: The average benzene concentration measured in the ambient air of the workplace of all studied industrial settings in Alexandria, Egypt; was 97.56±88.12 μg/m³ (range: 4.69–260.86 μg/m³). Levels of phenol and muconic acid were signifi cantly (p < 0.001) higher in both blood and urine of benzene-exposed workers as compared to non-exposed controls. Conclusions: The e-nose technology has successfully classifi ed and distinguished benzene-exposed workers from non-exposed controls for all measured samples of blood, urine and the exhaled air with a very high degree of precision. Thus, it will be a very useful tool for the low-cost mass screening and early detection of health hazards associated with the exposure to benzene in the industry.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2013, 26, 1; 165-172
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formulations of Bacillus Spp. and Pseudomonas Fluorescens for Biocontrol of Cantaloupe Root Rot Caused by Fusarium Solani
Autorzy:
Sallam, N.A.
Riad, S.N.
Mohamed, M.S.
El-eslam, A.S.
Powiązania:
https://bibliotekanauki.pl/articles/65978.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The aim of this study was to evaluate the different carrier formulations of antagonistic bacteria on incidence of root rot disease of cantaloupe. Twenty-seven isolates of bacteria isolated from rizosphere cantaloupe plants (collected from different localities of the Assiut Governorate, Egypt) were tested in vitro against the growth of Fusarium solani. The tested isolates exhibited varied percentages of mycelial inhibition of F. solani. The highly antagonistic bacteria isolates were identified as Bacillus subtilis, Bacillus cereus, and Pseudomonas fluorescens. The effect of talc based powder and wood flour as various carrier formulations of antagonistic bacteria were tested on incidence of cantaloupe root rot disease in greenhouse and field experiments. All tested carrier formulations of antagonistic bacteria significantly decreased the disease index percentage (p > 0.05) of root rot disease compared with the control, in greenhouse or in field experiments. Application of the wood flour formulation to the infested soil at the time of planting, gave the lowest disease (21.75%) index percentage compared to an application fifteen days before planting (26.83%). The reverse effect occurred in the case of the talc based powder formulation application. In field experiments, during the two growing seasons of 2009 and 2010, wood flour formulation gave the same effect in the reduction of the disease index when added before planting or at the time of planting to soil infested with the pathogen. However, application of the talc formulation at the time of planting showed the least disease index compared to when it was applied fifteen days before planting. In general, wood flour formulation significantly decreased the disease index when compared with the talc formulation. In all the formulations, a number of viable colonies of bioagents were decreased gradually by prolonging the storage time at 4°C. Storage time was prolonged up to five months. But in the case of B. subtilis on talc and B. cereus on wood flour formulations, storage time needed to be prolonged up to seven months.
Źródło:
Journal of Plant Protection Research; 2013, 53, 3
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition of Brass Corrosion in Acid Medium Using Thiazoles
Autorzy:
Taha, K. K.
Mohamed, M. E.
Khalil, S. A.
Talab, S. A.
Powiązania:
https://bibliotekanauki.pl/articles/411634.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Benzothiazoles
Brass Corrosion Inhibitors
Perchloric Acid
Opis:
Brass as an alloy composed mainly of copper is great industrial uses such as heat exchangers and similar other facility due to its good thermal properties. Due to the presence of the considerable ratio of zinc the alloy suffers from zinc dissolution or dezincification. Dezincification rate increases with the increase in the ratio of zinc in the alloy. In this study benzothiazole (BTH) and its substituent’s 2-methylbenzothiazole (MeBTH), 2-aminobenzothiazole (ABTH), 2-mercaptobenzothiazole (MBTH) and 2-phenylbenzothiazole (PhBTH) have been used as corrosion inhibitors for α-brass in stirred 0.1 M HClO4. The methods of investigation include weight loss, Tafel and linear polarizations and electrochemical impedance spectroscopy. The order of inhibition efficiency (% E) was calculated and the values obtained has indicated the sequence of inhibition efficiency was found to be BTH < MeBTH < ABTH < PhBTH < MBTH. The calculated values of thermodynamic parameters support this order. The inhibitors were found to suppress the corrosion rate by the formation of films which were identified by IR, SEM and EDAX techniques.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 9, 2; 87-102
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minerals content, essential oils composition and physicochemical properties of Citrus jambhiri Lush. (Rough Lemon) from the Sudan
Autorzy:
Mohammed, A. M. H.
Ibrahim, M. A
Omran, A. A.
Mohamed, E. M.
Elsheikh, S. E. M.
Powiązania:
https://bibliotekanauki.pl/articles/412508.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Citrus jambhiri
Rutaceae
atomic absorption spectroscopy (AAS)
Flame Atomic Emission Spectroscopy (FAES)
metal content
essential oils
Opis:
Minerals content of Citrus jambhiri (rough lemon) fruit was qualitatively and quantitatively analyzed using atomic absorption spectroscopy (AAS) and flame atomic emission spectrometry (FAES). The peel, moisture and ash contents of rough lemon were found to be 18.35 %, 23.75 % and 2.04 % respectively. Vitamin C (ascorbic acid) of rough lemon juice was found to be 70.0 mg/100 g. The chemical composition of essential oil of rough lemon peel was determined. The major compound was found to be limonene (84.5 %) followed by sabinene, β-myrcene, α-terpineol, 1,3-tetradecadiene and linalool.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 9, 1; 25-30
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suitability of Centella Asiatica (Pegaga) as a Food Source for Rearing Spodoptera Litura (F.) (Lepidoptera: Noctuidae) under Laboratory Condition
Autorzy:
Javar, S.
Sajap, A.S.
Mohamed, R.
Hong, L.W.
Powiązania:
https://bibliotekanauki.pl/articles/65387.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
When conducting entomological research, it is necessary to have a sufficient quantity of the desired pest. One of the pests commonly used in research is Spodoptera litura. Mass rearing of herbivorous caterpillars like S. litura requires large amounts of a suitable food source. Hence, the use of an easy-to-grow host plant would be most practical and reasonable. Centella asiatica known as ‘pegaga’ grows easily, produces plenty of leaves, and is available throughout the year in Malaysia. The suitability of C. asiatica as a food source for S. litura was evaluated by studying the biology of this pest on excised C. asiatica leaves, under laboratory conditions. S. litura completed its whole life cycle in 29 to 35 days. The mean pupal weight and the average number of eggs laid by a single female were 0.341 g and 1,930 eggs, respectively. Daily monitoring of the larval development stages as well as analysis on the width of head capsules, revealed the existence of six instars during the larval stages of S. litura. The cumulative survival rate for immature developmental stages was 80%, while the stage-specific survivorship was over 90%. This study demonstrated the use of ‘pegaga’ as a suitable new food source for when rearing S. litura larvae in the laboratory.
Źródło:
Journal of Plant Protection Research; 2013, 53, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Perkinsus sp. (Alveolata, Perkinsidae) a Parasite of the Clam Meretrix meretrix (Veneridae) from Arabian Gulf: Ultrastructural Observations of the Trophozoites and the Cellular Response of the Host
Autorzy:
ABDEL-BAKI, Abdel-Azeem S.
AL-QURAISHY, Saleh
Dkhil, Mohamed A.
OLIVEIRA, Elsa
Casal, Graça
AZEVEDO, Carlos
Powiązania:
https://bibliotekanauki.pl/articles/763467.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Perkinsus, trophozoite, encapsulation, ultrastructure, clam, Meretrix meretrix, Arabian Gulf
Opis:
Genus Perkinsus Levine, 1978 (Alveolata, Perkinsidae) an intracellular pathogenic parasite is described from the mantle and gill filaments of a commercially important clam, Meretrix meretrix, collected from the Arabian Gulf, Saudi Arabia. This genus contains currently seven named species: P. marinus, P. olseni (P. atlanticus), P. chesapeaki (P. andrewsi), P. mediterraneus, P. honshuensis, P. beihaiensis and P. qugwadi. Meanwhile, some unnamed Perkinsus sp. have been described in wide variety of mollusc species. Ultrastructural features of Perkinsus sp. trophozites and the host reaction are described. The different developmental stages of trophozoites appeared as single or grouped cells surrounded by amorphous material that constituted cysts or nodules randomly distributed throughout the connective tissue of the mantle. The early trophozoites were generally spherical to ellipsoidal with a circular nucleus containing a prominent central nucleolus. The cytoplasm had several small vacuoles which coalesce to form a great vacuole in the later trophozoites and the nucleus becomes eccentric. Some lomosomes were observed between the wall and the plasmalemma of trophozoites. A large number of degraded and pyknotic cell and several cellular structure with lysed aspects were encountered in the surrounding area near the cysts. Ultrastructural data showed that the lysed granular cells and the coalescence of the granules result in the cyst that encapsulates various trophozoites. In the current study, we describe for the first time the presence of Perkinsus sp. as well as the host reaction in clams from the Saudi Arabian coasts.
Źródło:
Acta Protozoologica; 2014, 53, 2
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prevalence of intestinal parasites among the population of the Gaza Strip, Palestine
Autorzy:
Mezeid, N.
Shaldoum, F.
Al-Hindi, A.I
Mohamed, F.S.A.
Darwish, Z.E.A.
Powiązania:
https://bibliotekanauki.pl/articles/5938.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
prevalence
intestinal parasite
parasite
population
health problem
Gaza Strip region
Palestine
Opis:
Intestinal parasitic diseases in Gaza Strip are a significant health problem. The main aim of this study is to determine the prevalence of parasitic infection among patients in the five governorates of the Gaza Strip. A crosssectional parasitological survey was conducted on 600 patients. Stool specimens were examined microscopically for the presence of parasite eggs or larvae/cysts per wet amount by the saline iodine and formol-ether concentration method. Of 600 subjects examined, 245 (40.8%) were infected with one or more intestinal parasites. Entamoeba histolytica/dispar and Giardia lamblia were the most prevalent parasites amongst the population (28.8%), (9.5%). Female patients demonstrated a higher prevalence of intestinal parasitic infections (42.7%) than males (39.0%). However, this difference was not significant (p>0.05). According to occupation, the rate of infection was highest among farmers (56.0%), followed by employers (44.2%) with laborers showing the lowest rate (30.17%). These differences in occupational prevalence were found to be statistically significant (p<0.05). The present study demonstrates that intestinal protozoan infections are still a public health problem in the Gaza strip, with Entamoeba and Giardia infections being most common. Therefore, it is necessary to develop effective prevention and control strategies, including health education and environmental sanitation improvement.
Źródło:
Annals of Parasitology; 2014, 60, 4
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality assessment of the essential oil from Eucalyptus globulus Labill of Blida (Algeria) origin
Autorzy:
Boukhatem, M. N.
Amine, F. M.
Kameli, A.
Saidi, F.
Walid, K.
Mohamed, S. B.
Powiązania:
https://bibliotekanauki.pl/articles/411538.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eucalyptus globulus Labill
Chemical composition
Essential oil
Gas Chromatography
Eucalyptol
Opis:
Despite the reputation earned by aromatic and medicinal plants of Algeria, the chemical constituents of Eucalyptus globulus essential oil (EGEO) of Blida origin has not previously been investigated. Thus, the present study has been conducted for the determination of chemical constituents and different physico-chemical properties of the EGEO. Chemical composition of the EGEO, grown in Algeria, was analysed by Gas Chromatography-Mass Spectrometry. The chemical components were identified on the basis of Retention Time and comparing with mass spectral database of standard compounds. Relative amounts of detected compounds were calculated on the basis of GC peak areas. Fresh leaves of E. globulus on steam distillation yielded 0.96 % (v/w) of essential oil whereas the analysis resulted in the identification of a total of 11 constituents, 1.8 cineole (85.8 %), α-pinene (7.2 %), and β-myrcene (1.5 %) being the main components. Other notable compounds identified in the oil were β-pinene, limonene, α-phellandrene, γ-terpinene, linalool, pinocarveol, terpinen-4-ol, and α-terpineol. The physical properties such as specific gravity, refractive index and optical rotation and the chemical properties such as saponification value, acid number and iodine number of the EGEO were examined. The oil extracted has been analyzed to have 1.4602 - 1.4623 refractive index value, 0.918 - 0.919 specific gravity (sp.gr.), +9 - +10 optical rotation that satisfy the standards stipulated by European Pharmacopeia. All the physical and chemical parameters were in the range indicated by the ISO standards. Our findings will help to access the quality of the Eucalyptus oil which is important in the production of high value essential oils that will help to improve the economic condition of the community as well as the nation.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 17, 3; 303-315
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended finite element numerical analysis of scale effect in notched glass fiber reinforced epoxy composite
Rozszerzona analiza numeryczna metodą elementów skończonych efektu skali w epoksydowym kompozycie z karbem wzmocnionym włóknem szklanym
Autorzy:
Abdellah, M. Y.
Alsoufi, M. S.
Hassan, M. K.
Ghulman, H. A.
Mohamed, A. F.
Powiązania:
https://bibliotekanauki.pl/articles/139922.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
XFEM
extended finite element method
composite laminate
fracture processing zone
crack opening displacement
rozszerzona metoda elementów skończonych
laminat kompozytowy
strefa procesu pęknięcia
przemieszczenie otworu szczeliny
Opis:
Nominal strength reduction in cross ply laminates of [0/90]2s is observed in tensile tests of glass fiber composite laminates having central open hole of diameters varying from 2 to 10 mm. This is well known as the size effect. The extended finite element method (XFEM) is implemented to simulate the fracture process and size effect (scale effect) in the glass fiber reinforced polymer laminates weakened by holes or notches. The analysis shows that XFEM results are in good agreement with the experimental results specifying nominal strength and in good agreement with the analytical results based on the cohesive zone model specifying crack opening displacement and the fracture process zone length.
Zmniejszenie nominalnej wytrzymałości laminatu warstwowego z poprzecznym ułożeniem włókien typu [0/90]2s jest obserwowane dla naprężeń rozciągających w laminatach kompozytowych z włóknem szklanym mających centralny otwór o średnicy od 2 do 10 mm. Jest to dobrze znany efekt rozmiaru (efekt skali). Rozszerzona analiza metodą elementów skończonych (XFEM) została zastosowana w celu symulacji procesu pękania i efektu skali w polimerowych laminatach z włóknem szklanym osłabionych obecnością karbu lub otworu. W pracy wykazano, że wyniki metody XFEM dotyczące wytrzymałości nominalnej są zgodne z danymi eksperymentalnymi, dobrze zgadzają sią z wynikami analitycznymi opartymi na modelu strefy spójnej i pozwalają określić przemieszczenie otworu szczeliny i długość strefy procesu pęknięcia.
Źródło:
Archive of Mechanical Engineering; 2015, LXII, 2; 217-236
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential toxicity assessment of novel selected pesticides against sand termite, Psammotermes hypostoma Desneux workers (Isoptera: Rhinotermitidae) under field conditions in Egypt
Autorzy:
Ahmed, M.A.I.
Eraky, E.-S.A.
Mohamed, M.F.
Soliman, A.-A.S.
Powiązania:
https://bibliotekanauki.pl/articles/66459.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The sand termite, Psammotermes hypostoma Desneux is a major pest in the New Valley Governorate, Egypt. Great efforts have been taken to control the pest. We evaluated the toxicity of four selected neonicotinoids [acetamiprid (20% SP), imidacloprid (20% SL), thiamethoxam (18.6% SC), and thiamethoxam (40% WG)], and one organophosphate pesticide [chlorpyrifos (48% EC)] against P. hypostoma workers. The investigation was done under field conditions, using the palm fronds method. However, the reduction percentages in palm fronds was recorded as the height of the sandy clay formed by termite workers on palm frond surfaces, when the fronds had been treated with a different concentration of each pesticide. The results were recorded after 15, 30, 45, and 60 days. Chlorpyrifos (48% EC) was considered the most potent pesticide among all the pesticides tested, but acetamiprid (20% SP) was considered the most toxic among the neonicotinoid pesticides tested. Moreover, the formulation of thiamethoxam (18.6% SC) was more powerful than thaimethoxam (40% WG). Furthermore, the reduction percentages on palm fronds increased significantly with an increase of the exposure period (from 15 to 60 days), as a result of the surface foraging activity of the sand termite workers. These results are given as unique and encouraging trends in controlling sand termites in Egypt.
Źródło:
Journal of Plant Protection Research; 2015, 55, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability analysis and prediction for time to failure distribution of an automobile crankshaft
Analiza niezawodności i przewidywanie rozkładu czasu do uszkodzenia wału korbowego pojazdu samochodowego
Autorzy:
Singh, S. S. K.
Abdullah, S.
Mohamed, N. A. N.
Powiązania:
https://bibliotekanauki.pl/articles/301436.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability
time to failure
monotonic function
hazard rate
niezawodność
czas do uszkodzenia
funkcja monotoniczna
wskaźnik zagrożenia
Opis:
This paper emphasizes on analysing and predicting the reliability of an automobile crankshaft by analysing the time to failure (TTF) through the parametric distribution function. The TTF was modelled to predict the likelihood of failure for crankshaft during its operational condition over a given time interval through the development of the stochastic algorithm. The developed stochastic algorithm has the capability to measure the parametric distribution function and validate the predict the reliability rate, mean time to failure and hazard rate. T, the algorithm has the capability to statistically validate the algorithm to obtain the optimal parametric model to represent the failure of the component against the actual time to failure data from the local automobile industry. Hence, the validated results showed that the three parameter Weibull distribution provided an accurate and efficient foundation in modelling the reliability rate when compared with the actual sampling data. The suggested parametric distribution function can be used to improve the design and the life cycle due to its capability in accelerating and decelerating the mechanism of failure based on time without adjusting the level of stress. Therefore, an understanding of the parametric distribution posed by the reliability and hazard rate onto the component can be used to improve the design and increase the life cycle based on the dependability of the component over a given period of time. The proposed reliability assessment through the developed stochastic algorithm provides an accurate, efficient, fast and cost effective reliability analysis in contrast to costly and lengthy experimental techniques.
W prezentowanej pracy przedstawiono metodę analizy oraz predykcji niezawodności wału korbowego pojazdu samochodowego opartą na analizie czasu do uszkodzenia (TTF) z wykorzystaniem funkcji rozkładu parametrycznego. W artykule, stworzono model TTF pozwalający na przewidywanie prawdopodobieństwa uszkodzenia wału korbowego w stanie pracy w danym przedziale czasu za pomocą nowo opracowanego algorytmu stochastycznego. Opracowany algorytm stochastyczny umożliwia mierzenie funkcji rozkładu parametrycznego oraz weryfikację przewidywanego współczynnika niezawodności, średniego czasu do uszkodzenia oraz współczynnika zagrożenia. Algorytm daje możliwość statystycznej weryfikacji modelu w odniesieniu do rzeczywistych danych dotyczących czasu do uszkodzenia pochodzących z lokalnego przemysłu samochodowego. Weryfikacja taka pozwala na otrzymanie optymalnego modelu parametrycznego reprezentującego uszkodzenie części składowej. Zweryfikowane wyniki wykazały, że trójparametrowy rozkład Weibulla stanowi dokładne i wydajne narzędzie do modelowania współczynnika niezawodności w zestawieniu z rzeczywistymi danymi z próby. Proponowaną dystrybuantę parametryczną można wykorzystywać do doskonalenia konstrukcji oraz cyklu życia wału korbowego ponieważ daje ona możliwość przyspieszania i zwalniania mechanizmu uszkodzenia, na podstawie czasu, bez potrzeby regulacji poziomu naprężenia. Zatem, znajomość rozkładu parametrycznego oraz obliczonych na jego podstawie współczynników niezawodności i zagrożenia omawianego elementu mechanizmu korbowego, pozwala na doskonalenie konstrukcji oraz wydłużenie cyklu życia wału korbowego w oparciu o dane dotyczące jego niezawodności w danym okresie czasu. Proponowana metoda oceny niezawodności z wykorzystaniem opracowanego w artykule algorytmu stochastycznego umożliwia dokładną, wydajną, szybką i tanią analizę niezawodności w odróżnieniu od kosztownych i czasochłonnych technik eksperymentalnych.
Źródło:
Eksploatacja i Niezawodność; 2015, 17, 3; 408-415
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 29

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