Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Boron, A." wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 90
Tytuł:
The Effect of Heavy Metals on the Growth of Waterborne Escherichia coli of Municipal Landfill Origin
Wpływ metali ciężkich na wzrost Escherichia coli izolowanych z wód pochodzących ze składowiska odpadów komunalnych
Autorzy:
Frączek, K.
Ropek, D.
Lenart-Boroń, A.
Powiązania:
https://bibliotekanauki.pl/articles/388581.pdf
Data publikacji:
2016
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
municipal waste landfill
Escherichia coli
heavy metals
municipal waste
składowisko odpadów komunalnych
metale ciężkie
odpady komunalne
Opis:
The aim of this study was to assess the sensitivity of Escherichia coli isolates originating from a municipal waste landfill to the selected heavy metals. The analyses were conducted using environmental strains, isolated from surface water – a stream flowing along the landfill and from leachate and the observations were compared to the reaction of a reference strain EC ATCC 25922. The growth rate of bacterial cultures was evaluated in the liquid medium supplemented with 0.02; 0.1 and 0.5 mg dm–3 of heavy metal salts: chromium, zinc, cadmium, copper, lead and mercury. The bacterial growth was examined turbidimetrically every 24 hours for 5 days. The performed study showed differences between the examined isolates in their response to the addition of the heavy metals in the liquid medium. Additionally, varied intensity of the heavy metals’ effect on bacterial growth was observed, with the weakest growth inhibition being recorded in the case of lead, while chromium and mercury causing the greatest growth inhibition of bacterial strains.
Celem pracy była ocena wrażliwości izolatów Escherichia coli, pochodzących ze składowiska odpadów komunalnych na działanie wybranych metali ciężkich. Badaniu poddano izolaty środowiskowe, pochodzące z wody powierzchniowej – strumienia płynącego wzdłuż składowiska oraz z odcieków, a także szczep wzorcowy EC ATCC 25922. Ocenie poddano tempo wzrostu kultur bakteryjnych w podłożu płynnym z dodatkiem 0,02; 0,1 oraz 0,5 mg dm–3 soli metali ciężkich: chromu, cynku, kadmu, miedzi, ołowiu i rtęci. The Effect of Heavy Metals on the Growth of Waterborne Escherichia coli... 183 Wzrost bakterii badano turbidymetrycznie w odstępach 24-godzinnych przez okres 5 dni. Na podstawie przeprowadzonych badań stwierdzono różnice pomiędzy badanymi izolatami w ich reakcji na obecność badanych metali ciężkich w podłożu. Zaobserwowano także różną intensywność działania metali, przy czym najsłabsze zahamowanie wzrostu bakterii stwierdzono w przypadku ołowiu, natomiast najsilniejszy efekt hamujący miały chrom i rtęć.
Źródło:
Ecological Chemistry and Engineering. A; 2016, 23, 2; 173-184
1898-6188
2084-4530
Pojawia się w:
Ecological Chemistry and Engineering. A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intraspecific molecular variation of Allium ursinum (Amaryllidaceae) across the border of two subspecies distribution ranges
Autorzy:
Rola, K.
Lenart-Boron, A.
Boron, P.
Osyczka, P.
Powiązania:
https://bibliotekanauki.pl/articles/19331.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The study investigates the genetic differentiation among two subspecies of Allium ursinum L., namely A. ursinum subsp. ursinum and subsp. ucrainicum as well as their putative hybrid that is represented by individuals with intermediate morphology. Inter-Simple Sequence Repeats (ISSR) were applied to determine the status of intermediate morphotypes in terms of their genetic pattern and to assess the level of genetic variability within and between various populations of A. ursinum. The study comprises 144 specimens from nine populations along the east-west transect in Poland, which includes localities of both subspecies and their putative hybrid. Among the examined populations, 48 bands were amplified, of which 45 were found to be polymorphic. The principal coordinate analysis (PCoA), the neighbour-net analysis and Mantel test showed a strong correlation between genetic variability and geographic distance. Analysis of molecular variance (AMOVA) revealed that a greater proportion of total genetic variation resided within populations rather than among them. The Structure Bayesian clustering analysis revealed the presence of three distinct genetic groups within studied populations, where 'eastern' genotypes correspond to A. ursinum subsp. ucrainicum, and 'western' to subsp. ursinum; whereas the third genetic group has the largest share in the individuals occurring at the border of the distribution ranges of both subspecies. The emergence of the third genetic group is probably an effect of hybridization events occurring within the secondary contact zone. Typical morphologically intermediate populations occur only in a relatively narrow geographical zone, but the hybrid zone revealed by molecular markers is actually much wider than it is suggested by the morphological pattern of individuals. The current distribution pattern of both subspecies of A. ursinum and their hybrid zone is related to the two main directions of postglacial migration of Fagus sylvatica to the area of Poland. The hybrid zone arose as an effect of the secondary contact of two divergent lineages of A. ursinum.
Źródło:
Acta Biologica Cracoviensia. Series Botanica; 2015, 57, 1
0001-5296
Pojawia się w:
Acta Biologica Cracoviensia. Series Botanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microbiological and physicochemical quality of leachate and water in the vicinity of a municipal landfill
Jakość mikrobiologiczna i fizykochemiczna odcieków i wód w rejonie składowiska odpadów komunalnych
Autorzy:
Frączek, K.
Ropek, D.
Lenart-Boroń, A.
Strojny, J.
Powiązania:
https://bibliotekanauki.pl/articles/388879.pdf
Data publikacji:
2017
Wydawca:
Towarzystwo Chemii i Inżynierii Ekologicznej
Tematy:
municipal landfill
groundwater
leachate
surface water
składowisko odpadów komunalnych
wody podziemne
odcieki
wody powierzchniowe
Opis:
This study aimed to assess microbiological and physicochemical quality of landfill leachate and water in the landfill’s vicinity. Nine samples consisting of groundwater, surface water and leachate were collected within and in the vicinity of a municipal landfill site in Tarnow. Physicochemical analyses of groundwater and leachate included: determination of pH, electric conductivity, heavy metal concentration (Pb, Cd, Cu, Zn, Cr VI and Hg) and sum of policyclic aromatic hydrocarbons. Surface water analyzes were complemented with the determination of Ni, As, Ag, V, volatile phenols concentration, content of total nitrogen and phosphorus, as well as CODCr and BOD5 Microbiological analyzes consisted of determination of total mesophilic and psychrophilic bacteria, Staphylococcus spp., Salmonella spp., the number of coliforms and fecal coliforms, Enterococcus faecalis, Clostridium perfringens, yeast and mold fungi. No threshold values concerning the examined chemical contaminants were exceeded in any of the water or leachate samples. However, the landfill vicinity resulted in severe microbiological contamination of surface and groundwater, which contained high concentrations of not only mesophilic bacteria but also fecal and pathogenic microorganisms. The results of this study revealed that waste and leachates are a major source of microbial emissions. Therefore, there is a need to conduct both physico-chemical and microbiological analyzes of the landfill-surrounding environment and this necessity should be legally enforced.
Celem badań była ocena mikrobiologicznej i fizykochemicznej jakości odcieków oraz wód w rejonie składowiska odpadów komunalnych. Przebadano 9 próbek wód podziemnych, wód powierzchniowych i odcieków zebranych na terenie oraz w rejonie składowiska odpadów komunalnych w Tarnowie. Analizy fizykochemiczne wód podziemnych i odcieków obejmowały: oznaczenie pH, przewodności elektrolitycznej, stężenia metali ciężkich (Pb, Cd, Cu, Zn, Cr VI i Hg) oraz sumy wielopierścieniowych węglowodorów aromatycznych. Analizy wód powierzchniowych uzupełniono o oznaczenie stężeń Ni, As, Ag, V, lotnych fenoli, całkowitego azotu i fosforu, a także ChZTr i BZT5 Wykonano również analizy mikrobiologiczne: oznaczenie ogólnej liczby bakterii mezofilnych i psychrofilnych, Staphylococcus spp., Salmonella spp., bakterii grupy coli, bakterii grupy coli typu kałowego, Enterococcus faecalis, Clostridium perfringens, drożdży i pleśni. Za równo w próbkach wód, jak i odcieków nie stwierdzono przekroczenia wartości granicznych dla żadnych z oznaczanych składników chemicznych. Zauważono jednak, że bliskie sąsiedztwo składowiska przyczynia się do znacznego skażenia mikrobiologicznego wód powierzchniowych i podziemnych, w których stwierdzono duże ilości nie tylko bakterii mezofilnych, lecz również wskaźników zanieczyszczenia kałowego, a także bakterii chorobotwórczych. Wyniki niniejszych badań wykazały, że odpady i odcieki ze składowisk są istotnym źródłem emisji drobnoustrojów do środowiska. W związku z tym ważne jest, aby na terenie i w bliskim sąsiedztwie składowisk prowadzone były nie tylko analizy fizykochemiczne, lecz również oznaczenia mikrobiologiczne, a także aby wprowadzić odpowiednie przepisy, regulujące konieczność i częstotliwość wykonywania wymienionych badań.
Źródło:
Ecological Chemistry and Engineering. A; 2017, 24, 2; 237-253
1898-6188
2084-4530
Pojawia się w:
Ecological Chemistry and Engineering. A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of IR thermography for testing operation parameters of plate steel and accumulative wood stoves
Autorzy:
Żołądek, M.
Sornek, K.
Boroń, A.
Nabożna, S.
Filipowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/114600.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
IR thermography
plate steel wood stoves
accumulative wood stoves
energy efficiency
Opis:
This paper shows the possibility of the use of IR thermography for testing the operational parameters of wood stoves. The study showed differences in the operation parameters of the plate steel wood stove, plate steel wood stove with accumulation and accumulative wood stove. There were compared temperature distribution on the external surfaces of tested units and the amount of energy transferred to heated rooms. Moreover, there were also tested two types of units dedicated to heat recovery from flue gas: flue gas to air steel heat exchanger and accumulative ceramic heat exchanger. The use of IR thermography allowed to simplify measurements and gave approximate results in comparison to more detailed tests.
Źródło:
Measurement Automation Monitoring; 2017, 63, 4; 162-165
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conservation of Primula farinosa in Poland with respect to the genetic structure of populations
Autorzy:
Gajewski, Z.
Boron, P.
Lenart-Boron, A.
Nowak, B.
Sitek, E.
Mitka, J.
Powiązania:
https://bibliotekanauki.pl/articles/58418.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
The bird’s-eye primrose (Primula farinosa L.) is an endangered species in Poland. The sole remaining, and critically endangered, population of approximately 300 flowering plants is located in the Beskid Sądecki Mountains (Jaworki, Poland). The genetic investigation was performed using highly variable microsatellite markers on a total of four populations: the Polish population and its three nearest known Slovak counterparts. We hypothesize that the Polish population is a relic of the previously much wider Central European mountain/lowland range and is thus genetically distinct from the rest of the Slovak stock. Clarification of this issue is needed before active protection interventions such as artificial supplementation can be carried out. Our results, particularly those from STRUCTURE Bayesian clustering, showed clear population structure within the dataset: all three Slovak populations were dominated by one genetic group, while the Polish population comprised mostly individuals dominated by the second genetic group. Only limited gene flow was observed between the Polish and Slovak populations. This demonstrates the distinct genetic makeup of the Jaworki population, which is probably the result of prolonged isolation from the rest of the P. farinosa range and admixture of genes from various lineages. Their origin could be determined by including plant material from the rest of the P. farinosa range, i.e., Scandinavian, Baltic, and Alpine/Carpathian locations, in a future study. The immediate practical application of our results is the recommendation that all supplementation interventions to the Jaworki population must be limited to plants produced from locally collected seeds.
Źródło:
Acta Societatis Botanicorum Poloniae; 2018, 87, 2
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using of boron waste as a shielding material on landmine detection with NBS imaging technique
Autorzy:
Baysoy, D.
Powiązania:
https://bibliotekanauki.pl/articles/1061969.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
28.20.Cz
28.20.Gd
28.20.Pr
Opis:
Boron wastes are produced as a result of production route of boron products and these wastes still contain a small amount of boron. In order to understand the possible use of boron waste in non-metallic landmine detection as a shielding, Monte Carlo simulations were applied by neutron backscattering imaging technique using two different neutron sources of ²⁵²Cf and deuterium-deuterium (D-D) reaction. NBS imaging detector system consists of a group of thermal neutron ³He detectors. To investigate the performance of the landmine detection system, a suitable shield around the neutron source was designed and this system was tested for localisation of buried landmine.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 569-571
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Vegetable Oils for the Friction Pair Modificated With a Boron
Zastosowanie olejów roślinnych w modyfikowanych borem węzłach ślizgowych
Autorzy:
Szczypiński-Sala, W.
Lubas, J.
Powiązania:
https://bibliotekanauki.pl/articles/189852.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
vegetable oils
friction
boron surface layer
oleje roślinne
tarcie
modyfikacja borem
Opis:
In the article, the results of the conducted research were discussed, and the aim was the evaluation of the characteristics of the operation of sliding pairs when vegetable oils are used for lubrication. Particularly, friction pairs with hard layers containing boron were taken into account. For comparison, two of the most common vegetable oils were used during the tests. Rapeseed oil was chosen, since it is most frequently applied in Europe, soybean oil was chosen due to its occurrence in North American areas. The oils are also applied in industry for commercial aims as oil bases for lubricants. The products based on vegetable oils can constitute an alternative for those of mineral origin. However, vegetable oils are characterized by different properties than mineral oils. The most essential issue is the fact that biolubricants are free of sulphurcontaining compounds that can have an unfavourable influence on the health of human beings. The wear measurements were conducted on a block-on-ing test stand T-05. In the sliding pair lubricated with vegetable oils, steel specimen interacted with a counterpart made of bearing alloy. In the second variant of a friction pair, a steel ring specimen with a boronized surface layer was used. The changes of the surface roughness of the specimen and counterpart during operation were evaluated. In the comparative evaluation, the best results were obtained choosing the sample with the hard layer lubricated with soybean oil. In this case, the observed wear of the surface of sliding pairs was the lowest. The lowest friction force and the lowest temperature of the elements of the friction pair also corresponded to this. The application of the TiB2 layer allows reducing the wear of both the sample with the layer and the counterpart with the bearing alloy layer.
W artykule omówiono wyniki przeprowadzonych badań, których celem była ocena charakterystyki pracy węzłów ślizgowych, do których smarowania zastosowano oleje roślinne. Podczas testów w celu porównania wykorzystano dwa najbardziej rozpowszechnione oleje roślinne. Wybrano jako najczęściej znajdujący zastosowanie na terenach europejskich olej rzepakowy oraz wykorzystywany w warunkach amerykańskich olej sojowy. Oleje te znajdują zastosowanie również w przemyśle do celów komercyjnych jako bazy olejów smarowych. Produkty oparte na olejach roślinnych stanowić mogą alternatywę dla tych pochodzenia mineralnego. Oleje roślinne charakteryzują się jednak odmiennymi właściwościami niż oleje mineralne. Najbardziej istotną kwestią jest to, iż nie zawierają one składników mogących niekorzystnie oddziaływać na zdrowie istot żywych. Pomiary sił tarcia i zużycia węzła smarowanego tymi olejami wykonano na testerze typu klocek--rolka T-05. W smarowanym olejami roślinnymi węźle współpracowała pierścieniowa próbka stalowa z przeciwpróbką pokrytą stopem łożyskowym. W drugim wariancie pary ciernej zastosowano pierścieniową próbkę stalową, na której zastosowano borowanie w postaci warstwy TiB2. Ocenie poddano zużycie współpracujących elementów oraz zmiany chropowatości ich powierzchni w trakcie pracy. W badaniach porównawczych najlepsze rezultaty uzyskano dla próbek z naniesioną powłoką TiB2 smarowanych olejem sojowym. W tym przypadku zużycie elementów pary ciernej było najmniejsze. Odpowiadały temu również najmniejsze wartości siły tarcia i temperatury podczas pracy.
Źródło:
Tribologia; 2018, 279, 3; 139-146
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cutting Mechanics when Turning Powder Metallurgy Produced Nickel-Cobalt Base Alloy with a Cubic Boron Nitride Insert
Autorzy:
Daź, Waldemar
Habrat, Witold
Tymczyszyn, Jarosław
Krupa, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2201808.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
tool wear
cutting forces
surface roughness
nickel-cobalt alloys
residual stress
cubic Boron Nitride
cubic Boron Nitride tool
Opis:
For the critical aero-engine parts it’s important to understand influence of cutting tools, cutting parameters, tool ware etc. on near surface condition which highly affect fatigue strength and at the same part life-time. New material implemented for the latest designs of aero-engines parts generate challenges for machining processes to fulfil strict requirements of aviation standards. Finish machining is the most important stage of process influencing fatigue strength. cBN tool are often used for final stage of machining. The objective of this study was analysis of cutting mechanics during finish turning of modern nickel-cobalt based alloy with cBN insert. Observations of cutting tool wear and cutting parameters influence on the components of cutting force, surface roughness and residual stress are presented in this paper.
Źródło:
Advances in Science and Technology. Research Journal; 2022, 16, 4; 163--175
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Occupational Exposure to Human Immunodeficiency Virus (HIV) - How Can We Reduce the Risk?
Autorzy:
Leszczyszyn-Pynka, M.
Kłys-Rachwalska, M.
Sacharczuk, B.
Boroń-Kaczmarska, A.
Powiązania:
https://bibliotekanauki.pl/articles/91111.pdf
Data publikacji:
2004
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
occupational exposure
HIV
health care workers
służba zdrowia
ekspozycja
higiena pracy
zagrożenia zdrowia
wypadki śmiertelne
profilaktyka medyczna
Opis:
We analyzed occupational exposure to potentially infectious body fluids among health care workers (HCWs). Nurses were the most common exposed category of HCWs. In 73.6% cases needle sticks had been the reason of exposure. Recapping a needle was the cause of exposure in 6.9% accidents. Among 189 registered HCWs, 66 (34.9%) performed invasive procedures without any personal protective equipment. Prophylaxis with antiretroviral drugs was necessary in 43 (22.8%) cases. As many as 60.3% of exposure incidents to potentially infectious material result from non-compliance with the relevant recommendations. Continuous education and training is critically needed to prevent occupational exposure to blood-borne infections among health care workers.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2004, 10, 4; 425-429
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the Effects of Boron Carbide Particle Size on Radiation Shielding Properties of Boron Carbide-Titanium Diboride Composites
Autorzy:
Buyuk, B.
Tugrul, A.
Aktop, S.
Addemir, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399664.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
25.20.Dc
Opis:
Boron carbide is a material which has wide application areas in industry including nuclear technology. Titanium diboride-boron carbide composites which were produced from different boron carbide particle sizes were studied for searching of the behaviour against the gamma ray. Micron size and submicron size boron carbide were used to produce composite materials. The volume of boron carbide and titanium diboride in the composites are 85% and 15%, respectively. For the investigation of the gamma radiation behaviour of these materials, Cs-137 radioisotope was used as gamma source in the experiments which has a single gamma-peak at 0.662 MeV. Gamma transmission technique was used for the measurements. The effects of boron carbide particle size on radiation attenuation of titanium diboride-boron carbide composites were evaluated in relation with gamma transmission and the results of the experiments were interpreted and compared with each other. It could be understood that decrease of particle size of boron carbide in boron carbide-titanium diboride composites causes higher linear and mass attenuation coefficient values. So, submicron size boron carbide used composite materials are more convenient than micron size boron carbide used composite materials as radiation shielding materials for nuclear applications.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 177-179
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Behaviour of Titanium Diboride Reinforced Boron Carbide-Silicon Carbide Composites against Cs-137 Gamma Radioisotope Source by Using Gamma Transmission Technique
Autorzy:
Buyuk, B.
Tugrul, A.
Akarsu, A.
Addemir, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490933.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
25.20.Dc
Opis:
Boron carbide is a material which has wide application areas in industry including nuclear technology. Titanium diboride reinforced boron carbide-silicon carbide composites were studied for searching of the behaviour against the gamma ray. It has been adopted that depending on their properties such improved materials can be used in nuclear technology. For the investigation of the gamma radiation behaviour of these materials, Cs-137 radioisotope was used as gamma source in the experiments which have a single gamma-peak at 0.662 MeV. Gamma transmission technique was used for the measurements. Different reinforcing ratios, titanium diboride reinforced boron carbide-silicon carbide composites were evaluated in relation to gamma transmission and the results of the experiments were interpreted and compared with each other. It could be understood that the increasing ratio of titanium diboride in boron carbide-silicon carbide composites causes higher hardness, strength and linear attenuation coefficient values but decrease the mass attenuation coefficient.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 135-137
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of boron dilution phenomenon in the core and fuel assemblies of Bushehr VVER-1000 reactor in normal operating conditions
Autorzy:
Rahmani, Y.
Zarifi, E.
Pazirandeh, A.
Powiązania:
https://bibliotekanauki.pl/articles/148568.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
VVER-1000
boron dilution
WIMS D5
CITATION
COBRA-EN
core and sub-channel analysis
Opis:
The spatial temperature distributions in fuel and coolant, results in appearing local changes in those elements densities in the reactor core, and also due to the complete solubility of boric acid in the coolant, there will be a direct correlation between the changes in the boron concentration and the coolant density. Because of the gradual reduction of boron concentration, first a local positive reactivity will be inserted into the core which will cause slight thermo-neutronic fluctuations in the reactor core. Of course, the trend of this process in the case of excessive reduction of the density of the coolant and evaporation of water (accident scenarios) will be reversed and subsequently the negative reactivity will be given to the system. With regard to the importance of this phenomenon, the spatial changes of boron concentration in the core and fuel assemblies of Bushehr VVER-1000 reactor have been examined. In line with this, by designing a complete thermo-neutronic cycle and by using CITATION, WIMS D-5 and COBRAN-EN codes, coolant temperature distribution and boron concentration will be calculated through this procedure, which first by using the output results of WIMS and CITATION codes, the thermal power of each fuel assembly will be calculated and finally, by linking these data to COBRA-EN code and using core and sub-channel analysis methods, the three-dimensional (3D) calculations of boron dilution will be obtained in the core as well as the fuel assemblies of the reactor.
Źródło:
Nukleonika; 2010, 55, 3; 323-330
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Density of States in Thin Boron-Doped Microcrystalline Silicon Films Estimated from the Thermally Stimulated Conductivity Method
Autorzy:
Dussan, A.
Schmidt, J.
Koropecki, R.
Powiązania:
https://bibliotekanauki.pl/articles/1207505.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Ln
73.61.Ga
61.72.uf
Opis:
In this work, a series of boron-doped microcrystalline silicon samples [μc-Si:H(B)] were deposited by plasma-enhanced chemical vapor deposition, using silane $(SiH_4)$ diluted in hydrogen, and diborane $(B_2H_6)$ as a dopant gas. The concentration of $B_2H_6$ in $SiH_4$ was varied in the range of 0-100 ppm. The density of states was obtained from the thermally stimulated conductivity technique and compared with results obtained by the modulated photoconductivity methods. To explain the poor agreement between the density of states obtained from the thermally stimulated conductivity and the other methods, it is shown by means of numerical simulations that the density of states is very sensitive to experimental errors introduced in the calculation of the $μ_{n}τ_{n}$ product (mobility of electron × lifetime of the electron). The thermally stimulated conductivity method is applied here for the first time to calculate the density of defect states in the forbidden band of μc-Si:H samples.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 174-176
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Boron on Crystallization and Microstructure of Ductile Cast Iron
Autorzy:
Dojka, R.
Studnicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/379815.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solidification process
metallography
ductile cast iron
boron
TDA
proces krzepnięcia
metalografia
żeliwo sferoidalne
bor
Opis:
The objective of the research was to determine the influence of boron on the crystallization process and microstructure of ductile cast iron. In the case of ductile cast iron it is a vital issue because even as little as trace presence of boron changes the properties of ductile cast iron in a significant way. With the use of a new ATD-4 (TDA) tester and CRYSTALDIGRPAH converter it was possible to measure the crystallization process parameters of the same alloy with four different contents of boron in one mould. Four samples with different boron contents were extracted, their microhardness was measured and quantitative analysis of microstructure was conducted. Obtained results allowed to state that with increasing content of boron the amount of graphite precipitates decreases, the amount of pearlite precipitates increases, the shape of graphite precipitates deteriorates and hardness increases. It is also planned to perform additional testings with boron contents between previously tested values.
Źródło:
Archives of Foundry Engineering; 2017, 17, 2; 15-20
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of boron on ZSM-5 catalyst for methanol to propylene conversion
Autorzy:
Xu, A.
Ma, H.
Zhang, H.
Ying, W.
Fang, D.
Powiązania:
https://bibliotekanauki.pl/articles/777971.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
methanol to propylene
ZSM-5
boron modifi cation
propylene
Opis:
B-ZSM-5 catalysts were prepared by various modification methods with boric acid, including ion-exchange, impregnation and direct synthesis. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), NH3-Temperature Programmed Desorption (NH3-TPD), N2 adsorption-desorption, Fourier Transform Infrared spectrometry (FT-IR), 27Al and 11B MAS NMR spectra. The results revealed that the weak acidity of catalysts was significantly increased by modification. The catalytic activity was measured in a fixed bed at 460°C for methanol to propylene (MTP) reaction. The results of MTP reaction showed a great increment of the propylene selectivity for the boron modified samples, especially for the directly synthesized B-ZSM-5 which also displayed high activity and selectivity towards C2 =-C4 = olefins. It was found that the remarkable selectivity strongly depended on the intensity of weak acidity.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 4; 95-101
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 90

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies