Wyniki wyszukiwania - Biblioteka Nauki

1

GaAs absorber grown at low temperature used in passively Q-switched diode pumped solid state laser

100%

Wang Y. , Ma X. , Wang C. L. , Lin T. , Zhen K. , Wang J. , Zhong L. , Jia Y. , Wei Z. Y.

Optica Applicata

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2006

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tom Vol. 36, nr 1

23-28

EN

We report, for the first time to the best of our knowledge, on a passively Q-switched Nd:YVO4 laser with a GaAs absorber grown at low temperature (LT) by metal organic vapor phase expitaxy. Using the LT GaAs absorber as well as an output coupler, a passively Q-switched laser whose pulse duration is as short as 90 ns was obtained.

2

Krioterapia - zastosowanie skrajnie niskich temperatur do celów leczniczych. Przegląd urządzeń do krioterapii miejscowej oraz ogólnoustrojowej

100%

Raczkowski J. , Daniszewska B.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2007

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tom Vol. 13, nr 1

58-60

PL

Zimno kriogeniczne we współczesnej medycynie ma szerokie zastosowanie. Najczęściej w fizjoterapii jako działanie bodźcowe i w kriochirurgii przy wymrażaniu tkanek patologicznych. W pracy przedstawiono zastosowanie niskich temperatur w fizjoterapii oraz współczesne aparaty i urządzenia do krioterapii.

3

Oddziaływanie niskich temperatur na organizm ludzki, czyli o zaletach krioterapii

100%

Giemza C. , Matczak-Giemza M.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2007

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tom Vol. 13, nr 1

65-65

PL

Krioterapia ogólnoustrojowa wykorzystuje fizjologiczne reakcje ustroju ludzkiego na krańcowo niskie temperatury. Do najważniejszych efektów należy zaliczyć działanie przeciwbólowe, przeciwobrzękowe, obniżające wzmożone napięcie mięśni szkieletowych. Jest metodą stosowaną w medycynie, sporcie i odnowie biologicznej. Dzięki swojemu dobroczynnemu działaniu oraz wysokiej skuteczności zyskuje coraz większą popularność w Polsce, a także w innych krajach.

EN

Systemie cryotherapy is based on physiological reaction of human organism on extremely low temperatures. The main therapeutic results include analgesic and anti-inflammatory effects and reduction of skeletal muscle tension. This method is important in rehabilitation process, sport medicine and may be valuable contribution to general fitness.

4

Electro-deposition parameters of boron carbonitride (bcn) from borax pentahydrate (NA2B4O7•5H2O)

100%

Tufan B. , Batar T.

Physicochemical Problems of Mineral Processing

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2016

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tom Vol. 52, iss. 1

136--146

EN

The primary objective of this research is the fabrication of boron end products from boron derivatives by electro-deposition as powder or coating. The production of boron carbonitride is achieved by electro-deposition at low temperatures without carbon dioxide emission, regardless of sintering and thermal treatment. The extensive usage of boron is aimed and should be accomplished by application of electro-deposition method for boron carbonitride fabrication.

5

Wpływ składu chemicznego na udarność staliwa typu Cr-Mo-V-Cu-Ni w ujemnej temperaturze

100%

Mikulska A.

Logistyka

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2010

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tom nr 6

PL

W artykule przedstawiono wyniki badań udarności w temperaturze -40 ?C staliw typu Cr-Mo-V-Cu-Ni. Badania oparte były o statystyczne metody planowania doświadczeń. Uzyskane wyniki poddane zostały analizie statystycznej, która posłużyła do określenia równań funkcji obiektu badań, jej zależności od zmiennych niezależnych i do wyznaczenia zakresu zmienności składu chemicznego staliwa o największej udarności w ujemnej temperaturze.

EN

This paper presents the results of impact toughness at -40 ?C type cast steel Cr-Mo-V-Cu-Ni. Tests were based on statistical methods for planning experiments. The results obtained were subjected to statistical analysis, which was used to determine the equations of the functions of research object, its dependence on the independent variables and to determine the range of variation of chemical composition of cast steel with the largest impact at low temperature.

6

Low temperature broad band dielectric spectroscopy of multiferroic Bi6Fe2Ti3O18 ceramics

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Lisińska-Czekaj A. , Rerak M. , Czekaj D. , Lubina M. , Garbarz-Glos B. , Bąk W.

Archives of Metallurgy and Materials

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2016

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tom Vol. 61, iss. 3

1447--1452

EN

In the present research the tool of broadband dielectric spectroscopy was utilized to characterize dielectric behavior of Bi6Fe2Ti3O18is (BFTO) Aurivillius-type multiferroic ceramics. Dielectric response of BFTO ceramics was studied in the frequency domain (Δν=0.1Hz - 10MHz) within the temperature range ΔΤ=-100°C - 200°C. The Kramers-Kronig data validation test was employed to validate the impedance data measurements and it was found that the measured impedance data exhibited good quality justifying further analysis. The residuals were found to be less than 1%, whereas the "chi-square" parameter was within the range χ2~-10-7 -10-5. Experimental data were analyzed using the circle fit of simple impedance arc plotted in the complex Z”-Z` plane (Nyquist plot). The total ac conductivity of the grain boundaries was thus revealed and the activation energy of ac conductivity for the grain boundaries was calculated. It was found that activation energy of ac conductivity of grain boundaries changes from ΕA=0.20eV to ΕA=0.55eV while temperature rises from Τ=-100°C up to Τ=200°C. On the base of maxima of the impedance semicircles (ωmτm=l) the relaxation phenomena were characterized in terms of the temperature dependence of relaxation times and relevant activation energy was calculated (ΕA=0.55eV).

7

The method for reliability estimation of the machine elements under low temperature conditions

100%

Vasilyev A. , Bakhracheva J.

Journal of KONES

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2009

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tom Vol. 16, No. 1

513-517

EN

The subject considered are the theoretical dependences between parameters in a small scale yielding zone length, and a plastic zone at cave-in spherical indentor. The loadings of a spherical (D=5 mm) indenter in the range from 147 to 11875 N within absolute temperature range 77-293 K were applied. According to this model, fracture conditions occur when the stress sigma z in the centre of ball impression exceeds critical stress of brittle fracture of. Then the indentation energy, corresponding to condition HM =sigma f, where HM and sigma f are the Meyer 's hardness and the material 's critical cleavage fracture stress, was calculated. The comparison of fracture toughness K Ic, and specific energy of plastic deformation on depth of a plastic zone at introduction spherical indentor up values reveals linear relation-ships KIc(up) for all steels in all the investigated temperature range. For the purposes of non-destructive Sk estimation, the relation-ship between S k and misses stress sigma i, in the centre of impression at the temperature 77 K was established. At last fracture toughness values can be calculated from the single unified equation for all investigated steels. The model proposed can be used for predicting the cracking resistance of the machine elements in a low temperature range.

8

Studies on the adaptation of influenza virus replicated at low temperature. III. Biochemical studies

100%

Brydak L.

Acta Microbiologica Polonica

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1990

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tom 39

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nr 1-2

9

Measurements of the dependence of wood’spermeability to air on the temperature of the pyrolysis

100%

Ronewicz K. , Heda Ł. , Kardaś D.

Transactions of the Institute of Fluid-Flow Machinery

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2015

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tom nr 128

131--138

EN

The paper deals with the wood’s (in this case pine) longitudinal permeability to air and its possible dependence on the temperature of the pyrolysis. The measurement of permeability was indirect and conducted on the original stand constructed solely for this purpose. Before every measurement a special sample preparation procedure was conducted for each sample group. Every group of samples was preheated up to the temperature previously set in the oxygen-less environment. After that, samples were cooled down to the room temperature. The following parameters were measured directly: sample length and diameter, pressure difference, and time. After numerous measurements of the mentioned values, the permeability of wood to air was calculated using the Darcy’s law for a given pyrolysis temperature. The results show a distinct dependence between the wood’s permeability to air and the pyrolysis temperature. The minimum value of the permeability is on the level of 0.56 D for temperature of 50 ◦C and is growing up to the value of 5.8 D (over ten times of the initial value) for the temperature of 350 ◦C.

10

The effect of low temperatures on the development of eggs of Ascaris suum Goeze, 1782

100%

Dziekonska-Rynko J. , Jablonowski Z.

Wiadomości Parazytologiczne

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2004

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tom 50

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nr 3

11

The influence of low temperatures on the change of basic mechanical properties of chosen polyurethane elastomers used in agricultural machines

100%

Stezala S.

Annual Review of Agricultural Engineering

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2006

|

tom 05

12

Role of epigenetic mechanisms in plant response to low temperature

88%

Achrem M. , Skuza A. , Kalinka A. , Szucko I. , Filip E. , Slominska-Walkowiak R. , Rogalska S. M.

Acta Biologica Cracoviensia. Series Botanica

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2012

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tom 54

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nr 1

EN

Plants are continuously exposed to various environmental stresses and they respond to them in different ways. Ambient temperature is among the most important environmental cues that directly influence plant growth and yield. Research in recent years has revealed that epigenetic mechanisms play a key role in plants' response to temperature stress. Changes in gene expression evoked by stress signals follow post-translational histone modifications, DNA methylation, histone variant incorporation, and the action of chromatin remodeling factors and Polycomb group proteins. The majority of epigenetic modifications induced by temperature stress are reversible in nature; thus, chromatin returns to its previous state after the stress has passed. Some modifications seem stable, however, due presumably to so-called stress memory. Epigenetic modifications can be inherited through mitosis and meiosis. By dint of epigenetic memory, plants can more efficiently respond to future stressful conditions, thereby increasing their potential for environmental adaptation. Recognition of the epigenetic mechanisms that take part in plants' response to changes of ambient temperature will increase our understanding of adaptations to stress conditions.

13

What do plants do in winter?

88%

Wojtyla Ł. , Adamiec M. , Sobieszczuk-Nowicka E.

Edukacja Biologiczna i Środowiskowa

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2014

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nr 1

3-11

EN

Plants can be divided according to susceptibility to cold or frost resistance owing to their tolerance. In the temperate climate, most plants are tolerant of low temperatures and have evolved mechanisms which enable them to survive the winter and limit the negative effects. Gradual temperature drops and the gradual shortening of days in the autumn are extremely important in preparing the plant for the winter. Reduction of cell membrane fluidity and a decrease in efficiency of photosynthesis are the main mechanisms for plant perception of weather conditions. This perception stimulates the induction of processes to acquire tolerance to unfavourable conditions by modulating gene expression, the accumulation of specific proteins with cryo-protective properties and the synthesis of osmotically active and antioxidant compounds. Some species overwinter as dormant, whereas others called evergreens, maintain metabolic activity adjusted to the winter conditions.

14

Analiza pracy ciepłowni geotermalnej wykorzystującej niskotemperaturowe źródło ciepła

88%

Nitkiewicz A. , Sekret R.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2009

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tom z. 26

265-273

PL

W artykule przedstawiono koncepcję ciepłowni geotermalnej wykorzystującej wody niskotemperaturowe zaopatrującej w ciepło pobliskie budynki użyteczności publicznej. Do celów analizy wybrany został otwór badawczy w gminie Poczesna (woj. śląskie) o samoczynnym wypływie 24 m3/h i średniej temperaturze wody równej 19,5 °C. Dla istniejącego otworu zaproponowano dwa układy ciepłowni z pompą grzejną: monowalnentny biwalentny. Analiza kosztów eksploatacyjnych wykazała, że proponowana ciepłownia geotermalna może stanowić alternatywę dla konwencjonalnych ciepłowni w przypadku gdy system ciepłowniczy zostanie skojarzony z systemem wodociągowym.

EN

In this paper the concept of low temperature goethermal heat-generating plant and its utilization for heating buildings was presented. For the analytical purposes the authors have chosen existing drilled well located in Poczesna community with average geothermal water temperature at 19,5 °C and 24 m3/h spontaneous outflow volume flux. For existing well the monovalent and the bivalent low temperature geothermal heating system with heat pump was taken into consideration. The operating cost analysis has shown that proposed geothermal heating plant could be an alternative for fossil fuel fired heating plant only in a case of combining heating system with water supply.

15

Low temperature synthesis and thermodynamic stability of fluorpyromorphite Pb5(PO4)3F at 5-65°C

88%

Dziura A. , Kwaśniak-Kominek M. , Manecki M. , Bajda T.

Geology, Geophysics and Environment

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2012

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tom Vol. 38, no. 4

465

EN

Fluorpyromorphite Pb5(PO4)3F belongs to the pyromorphite group of minerals which are isostructural with apatites. Their structure allows for variety of substitutions in both cationic and anionie positions. The purpose of this study is low temperature synthesis, mineralogical and thermodynamic characterization of fluorpyromorphite (FPY) and determination of its solubility product based on the results obtained from the dissolution experiment. FPY was synthesized by dropwise mixing of solutions containing Pb(NO3)2, K2HPO4 and NaF at 25°C. The only product of synthesis is FPY within the detection limits of X-ray diffraction. Calculated unit cell parameters are a = 9.1 ATI A, c = 7.3216 A. Homogeneous character of the precipitate was confirmed further with the use of scanning electron microscopy. Dissolution experiments were conducted in triplicates, open to the air, at 5, 25, 45°C and 65-C and at pH = 2.0. An aliquot of about 250 mg of FPY was placed in 250 mL of 0.05 M KNO3 with the pH adjusted using 0.1 M HNO3. Periodically taken samples were analyzed for [Pb] using atomic absorption spectrometry AAS as well as for [PO4] and [F] using colorimetry. Calculations of solubility products were performed with the aid of computer program PHREEQC with modified MINTEQ thermodynamic database. The activities of ionic species were calculated from measured concentrations of elements (assuming stoichiometric dissolution) with application of extended Debye-Huckel equation.

16

Effect of the Austempering Process on the Microstructure and Mechanical Properties of 27MnCrB5-2 Steel

88%

Morri A. , Ceshini L. , Pellizzari M. , Menapace C. , Vettore F. , Veneri E.

Archives of Metallurgy and Materials

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2017

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tom Vol. 62, iss. 2A

643--651

EN

The effect of austempering parameters on the microstructure and mechanical properties of 27MnCrB5-2 steel has been investigated by means of: dilatometric, microstructural and fractographic analyses; tensile and Charpy V-notch (CVN) impact tests at room temperature and a low temperature. Microstructural analyses showed that upper bainite developed at a higher austempering temperature, while a mixed bainiticmartensitic microstructure formed at lower temperatures, with a different amount of bainite and martensite and a different size of bainite sheaf depending on the temperature. Tensile tests highlighted superior yield and tensile strengths (≈30%) for the mixed microstructure, with respect to both fully bainitic and Q&T microstructures, with only a low reduction in elongation to failure (≈10%). Impact tests confirmed that mixed microstructures have higher impact properties, at both room temperature and a low temperature.

17

Reverse flotation of iron ore using amphoteric surfactant: 2-((2(decyloxy)ethyl)amino)lauric acid

88%

Luo B. , Zhu Y. , Sun C. , Li Y. , Han Y.

Physicochemical Problems of Mineral Processing

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2021

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tom Vol. 57, iss. 3

73--83

EN

2-((2-(decyloxy)ethyl)amino)lauric acid (C10H21CH(NH(CH2)3OC10H21)COOH, (LDEA), a novel amphoteric surfactant, has been first utilized as the collector for on-site the reverse flotation of Anqian mixed magnetic concentrates. The separation performances were investigated systematically by flotation conditioning tests, open-circuit flowsheet experiment, and locked cycle flowsheet test. The flotation condition test's results showed that the optimal roughing conditions were pulp pH of 10, starch dosage 1000 g/Mg, and LDEA dosage of 500 g/Mg at 25 °C. Under the optimized flotation conditions, through one roughing - three scavengings locked cycle flowsheet, the iron concentrate with a total iron grade of 68.08% and recovery of 88.20% was obtained. In contrast, the iron grade of the tailings was only 12.32%. Compared with the flotation results of anionic commercial surfactant RA-715 used as the collector, the LDEA has a better separation performance. The iron grade and recovery increased by 0.07% and 0.86% in the iron concentrate, and the grade of the tailings decreased 3.72%, respectively. Besides, the LDEA possesses more advantages, such as a simple flotation process, no activator (CaO) addition, lower collector consumption, and lower pulp temperature. The study revealed that the novel amphoteric surfactant LDEA was an effective flotation collector with good collecting and separation ability on natural iron ores at a comparatively lower temperature.

18

The mechanical properties at room and low temperature of P110 steel characterised by means of small punch test

88%

Romelczyk-Baishya B. , Lumelskyj D. , Stępniewska M. , Giżyński M. , Pakieła Z.

Archives of Metallurgy and Materials

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2019

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tom Vol. 64, iss. 1

159--165

EN

In this paper small punch test (SPT) which is one of miniaturized samples technique, was employed to characterize the mechanical properties of carbon steel P110. The tests were carried out in the range of -175°C to RT. Results obtained for SPT were compared to those calculated for tensile and Charpy impact test. Based on tensile and SPT parameters numerical model was prepared. 8 mm in diameter and 0.8 mm in height (t) discs with and without notch were employed in this research. The specimens had different depth notch (a) in the range of 0.1 to 0.4 mm. It was estimated that α factor for comparison of Tsp and DBTT for carbon steel P110 is 0.55 and the linear relation is DBTT = 0.55TSPT. The numerical model fit with force – deflection curve of SPT. If the factor of notch depth and samples thickness is higher than 0.3 the fracture mode is transformed from ductile to brittle at -150°C.

19

Chilling-sensitivity of maize. In search of new directions

88%

Sowinski P. , Rudzinska-Langwald A.

Polish Journal of Natural Sciences. Supplement

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2003

|

tom 01

20

Ciecze jonowe stosowane do sieciowania elastomerów w obniżonych temperaturach

75%

Pingot M. , Zaborski M.

Przemysł Chemiczny

|

2013

|

tom T. 92, nr 9

1657-1659

PL

Wykazano, że systemy zbudowane z wodoronadtlenku kumenu oraz amoniowych cieczy jonowych są skutecznymi układami sieciującymi elastomer butadienowo-styrenowy. Dokonano charakterystyki układów sieciujących za pomocą badań chemiluminescencji oraz wyznaczono energię aktywacji reakcji sieciowania. Zbadano kinetykę sieciowania mieszanek elastomerowych, a następnie gęstość usieciowania i właściwości mechaniczne wulkanizatów. Oceniono wpływ soli amoniowych na procesy starzenia wulkanizatów. Ponadto stwierdzono, że ciecze jonowe są związkami wielofunkcyjnymi odgrywającymi rolę koagentów sieciowania, jak również substancji dyspergujących.

EN

Five ionic liqus. (NH4+ salts) and (PhCMe2O)2 were used for curing butadiene-styrene rubber at 90°C. The process was followed by chemiluminescence. Use of the ionic liqs. resulted in decreasing the activation energy of cross-linking. Activity of the curing agent was detd. Addn. of SiO2 filler resulted in an increase in the tensile strength ageing resistance of vulcanizates. The ionic liqs. were found good co-agents and dispersing agents in rubber curring.