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Tytuł:
Relationship Between Chinese Speech Intelligibility of Elderly and Speech Transmission Index
Autorzy:
Peng, Jianxin
Zeng, Jiazhong
Zhao, Yuezhe
Powiązania:
https://bibliotekanauki.pl/articles/1953494.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
speech intelligibility
speech transmission index
signal-to-noise ratio
background noise level
speech sound pressure level
reverberation time
Opis:
In this paper, the relationship between Chinese speech intelligibility (CSI) scores of the elderly aged 60-69 and over 70 years old, and speech transmission index (STI) were investigated through the auralization method under different reverberation time and background noise levels (BNL, 40 dBA and 55 dBA). The results show that the CSI scores of the elderly are significantly worse than those of young adults. For the elderly over 70, the CSI scores become much lower than those of young adults. To be able to achieve the same CSI, the elderly, especially those over 70, need much higher STI and greater SNR than the young. The elderly aged 60-69 and over 70 need to improve their STI by 0.419 and 0.058 respectively under BNL 40 dBA, as well as 0.282 and 0.072 respectively under BNL 55 dBA, so as to obtain the same CSI scores as the young adults.
Źródło:
Archives of Acoustics; 2021, 46, 2; 229-235
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution of Aluminium Melt Quality of A356 After Several Recycling
Autorzy:
Gursoy, O.
Erzi, E.
Tur, K.
Dispinar, D.
Powiązania:
https://bibliotekanauki.pl/articles/1840918.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
A356
recycling
melt quality
reduce pressure test
bifilm index
recykling
topnienie
próba ciśnieniowa
Opis:
Recyclability is one of the great features of aluminium and its alloys. However, it has been typically considered that the secondary aluminium quality is low and bad. This is only because aluminium is so sensitive to turbulence. Uncontrolled transfer and handling of the liquid aluminium results in formation of double oxide defects known as bifilms. Bifilms are detrimental defects. They form porosity and deteriorate the properties. The detection and quantification of bifilms in liquid aluminium can be carried out by bifilm index measured in millimetres as an indication of melt cleanliness using Reduced Pressure Test (RPT). In this work, recycling efficiency and quality change of A356 alloy with various Ti additions have been investigated. The charge was recycled three times and change in bifilm index and bifilm number was evaluated. It was found that when high amount of Ti grain refiner was added, the melt quality was increased due to sedimentation of bifilms with Ti. When low amount of Ti is added, the melt quality was degraded.
Źródło:
Archives of Foundry Engineering; 2020, 20, 4; 61-66
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the Ballistic Parameters of a Deterred Triple Base Propellant Used in Large Caliber Ammunition
Autorzy:
Dahiwale, Sunil M.
Bhongale, Chetan J.
Roy, Shubhankar
Navle, Pradeep B.
Asthana, Shrinandan N.
Powiązania:
https://bibliotekanauki.pl/articles/357930.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
progressive burning
deterred propellant
BuNENA
pressure index
force constant
burning rate
chamber pressure
Opis:
In this work, the energetic plasticizer N-n-butyl-N-(2-nitroxyethyl)nitramine (Bu-NENA) was used as a deterrent coating for a triple base propellant (TBP) that finds application in large caliber guns. Closed vessel (CV) evaluation was performed to study the ballistic performance of the deterred propellant. A TBP containing nitrocellulose (NC), nitroglycerine (NG) and nitroguanidine (NQ) was coated with an energetic plasticizer using a solution of Bu-NENA. The Bu-NENA coated propellant exhibited inhibition to burning resulting in a reduction in the values of the ballistic parameters viz. (dP/dt)max, burning rate coefficient (β) and relative vivacity (RV), while the pressure index (α) and rise time were increased. The trends obtained during this work display the potential of Bu-NENA as deterrent.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 3; 449-467
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of methods of improving energy efficiency of pumping stations power units of water supply systems
Autorzy:
Nikolenko, I.
Shvagirev, P.
Powiązania:
https://bibliotekanauki.pl/articles/410678.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
energy efficiency
pumping unit
pressure
flow
regulation
working field
target value
index of efficiency
Opis:
The article shows the importance of the problem of improving efficiency of energy use in technical and technological systems. One of the ways of improving energy efficiency of water supply systems is the use of new energy-efficient technologies and pumping equipment, the use of modern management systems. Modern trends in the evaluation of energy consumption for operation of pumping equipment of water supply systems were analyzed. New methods of improving energy efficiency of pumping units in water supply system, taking into account the real operating conditions, were presented.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2018, 7, 1; 67-77
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of swell pressure in Neogene clays from Warsaw, based on the swell index
Autorzy:
Gawriuczenkow, I.
Wójcik, E.
Powiązania:
https://bibliotekanauki.pl/articles/184701.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
neogene clays
expansiveness
swell pressure
swell index
Opis:
The paper presents the results of swell measurements of Neogene clays (Posnanian clay) from the Mazovia region with different grain size distribution and mineral composition. The study was conducted with model soil with initial moisture contents of 15%, 20%, 25% and 30%. The basic physical properties of clays, their mineral composition and swelling parameters such as free swelling index and swelling pressure were determined. Free swell index was correlated to liquid limit, plasticity index, clay content and water content. A very high fit was found for a proposed relationship between the free swell index and swell pressure which offers an inexpensive method of predicting swell pressure in the preliminary stages of site investigation.
Źródło:
Geology, Geophysics and Environment; 2018, 44, 2; 219-229
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of aging and gender on plantar pressure distribution during the gait in elderly
Autorzy:
Gimunova, M.
Zvonař, M.
Mikeska, O.
Powiązania:
https://bibliotekanauki.pl/articles/307400.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
osoba starsza
chód
rozkład ciśnienia
stopa
elderly
gait
arch index
pressure distribution
foot progression angle
hallux angle
Opis:
The effect of age on structural foot characteristics as well as on the plantar pressure distribution has been shown previously. However, the number of studies focused also on gender gait differences of elderly is lacking. The purpose of this study was to compare dynamic gait characteristic in younger and older elderly and to investigate the gender differences as the life-long load and footwear choice differ in males and females. Methods: 61 healthy elderly participants were divided by age and gender into four groups: males 60–69, males 70–79, females 60–69 and females 70–79 years old. Plantar pressures were recorded during barefoot walking at naturally chosen speed using Emed-at (Novel GmbH, Germany). Three steps of the left foot of each participant were used for further analysis, furthermore, hallux angle, foot progression angle, and arch index were calculated by the Emed software from obtained footprints. To compare the differences between the analyzed groups, effect size obtained by Cohen’s d was used. Results: Comparing the two age male groups, higher mean pressure was found in the 70–79 age group in region MH4, MH5 and mid-foot, suggesting a greater lateral load and decreased longitudinal arch of the foot. Comparing female groups, the higher mean pressure was found in the older age group in region MH1. In all other regions, the mean pressures were reduced in the older groups. Conclusions: The results suggest that the effect of aging on plantar pressure distribution during the gait is affected by gender and should be considered when evaluating the gait of elderly.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 3; 139-144
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of swell index and swelling pressure from suction tests : a case study of Neogene clays from Warsaw (Poland)
Autorzy:
Wójcik, E.
Gawriuczenkow, I.
Powiązania:
https://bibliotekanauki.pl/articles/2060572.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
expansive soils
swell index
swelling pressure
soil suction
neogene clays
Opis:
The paper presents the results of swell index, swelling pressure and soil suction tests carried out on Neogene clays from Warsaw, depending on the water content, clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite. These clays are considered expansive soils in Poland, as they are vulnerable to water content variations in the active zone, which result in their volume change and, in consequence, cause damage of foundations and other construction elements. A number of physical, chemical and mineral properties were determined for these clays. The swelling tests were carried out on samples precompacted in Proctor apparatus, at various initial values of water content. The analyses have shown exponential relation of swell index, swelling pressure and suction versus water content. In addition, the investigated relationship between the suction and swell characteristics of tested clays shows good correlation as a power function between these parameters. In addition, validity of correlations between fitting parameters of obtained relationships and soil index properties, such as clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite, have been demonstrated. The empirical relations are characterized by high values of the correlation coefficient. A very high fit has also been found for a proposed relationship between the swell index and swelling pressure for tested clays.
Źródło:
Geological Quarterly; 2017, 61, 4; 738--750
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pyłowe atmosfery wybuchowe : parametry charakteryzujące wybuchowość pyłów
Explosive dust atmospheres : parameters characterizing explosive dust
Autorzy:
Domański, W
Powiązania:
https://bibliotekanauki.pl/articles/179234.pdf
Data publikacji:
2016
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
atmosfera wybuchowa
pyły
maksymalne ciśnienie wybuchu
maksymalna szybkość narastania ciśnienia wybuchu
współczynnik wybuchowości pyłu
dolna granica wybuchowości
minimalna energia zapłonu
explosive atmosphere
dusts
maximum explosion pressure
maximum rate pressure rise
deflagration index
lower explosive limit
minimum ignition energy
Opis:
Wyeliminowanie lub ograniczenie zagrożenia wynikającego z występowania w miejscach pracy pyłowych atmosfer wybuchowych wymaga poznania własności palnych i wybuchowych pyłów materiałów palnych. W artykule przedstawiono i scharakteryzowano parametry charakteryzujące właściwości wybuchowe pyłów palnych materiałów. Parametry charakteryzujące wybuchowość pyłów są zdefiniowane, a metody ich badań oraz zasady budowy i wymagania techniczne dla aparatów do badań są znormalizowane. W CIOP-PIB opracowano metody badań maksymalnego ciśnienia wybuchu, maksymalnej szybkości narastania ciśnienia wybuchu, współczynnika wybuchowości pyłu, dolnej granicy wybuchowości oraz minimalnej energii zapłonu. Opracowane metody spełniają wymagania techniczne i metodyczne nakreślone w normach PN-EN14034 i PN-EN 13821.
Eliminating or reducing risk arising from the presence of dust explosive atmospheres al the workplace requires knowing the flammable and explosive properties of dusts of combustible materials. This paper presents and characterizes parameters of the explosive properties of dusts of combustible materials. Parameters characterizing explosive dusts are defined, and methods of testing them and the principles of construction and technical requirements for testing apparatus are standardized CIOP-PIB developed test methods for maximum explosion pressure, the maximum rate of pressure rise, the deflagration index, the lower explosive limit and the minimum ignition energy. The developed methods meet the technical requirements and the methodology specified in standards PN-EN14034 and PN-EN13821.
Źródło:
Bezpieczeństwo Pracy : nauka i praktyka; 2016, 7; 14-17
0137-7043
Pojawia się w:
Bezpieczeństwo Pracy : nauka i praktyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of arch type and Body Mass Index on plantar pressure distribution during stance phase of gait
Autorzy:
Obrien, D. L.
Tyndyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/307001.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
body mass index
foot arch type
gait
plantar pressure distribution
indeks masy ciała
stopa
rozkład ciśnienia podeszwowego
Opis:
Several factors have been associated with the presence of abnormally high plantar foot pressure including: (i) increased body weight, (ii) foot structure and (iii) walking strategy. It is predicted that the biomechanics of the foot is influenced by the structure of the foot, primarily the Medial Longitudinal Arch. The objective of this study was to examine if Body Mass Index and the foot arch have a direct effect on dynamic peak plantar pressure for healthy subjects. Following a clinical lower limb examination, the Tekscan HR mat was utilised for this study, plantar pressure was profiled at specific events during stance phase of gait including heel strike, midstance and toe off. Results indicated to the preferable normal arch as this produced a low plantar pressure distribution in all cases. The 2nd and 3rd metatarsal head region recorded the highest pressure for all arch types during dynamic analysis. The lowest pressure for the normal and overweight BMI was at toe-off. While the obese BMI group showed highest pressure during toe-off. The obese BMI flat arch subcategory indicated to functional ambulation differences. Future work involves comparing this healthy database to a demographically matched diabetic group.
Źródło:
Acta of Bioengineering and Biomechanics; 2014, 16, 2; 131-135
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Negative Pressure and Cleaning Condition Effects on Gathering for Ramie Compact Spinning with a Suction Groove
Badanie podciśnienia i warunków czyszczenia na skupienie włókien ramii przy przędzeniu kompaktowym z rowkiem zasysającym
Autorzy:
Ma, H C
Cheng, L. D.
Yan, G X
Xu, S P
Powiązania:
https://bibliotekanauki.pl/articles/232971.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
suction groove
compact spinning
ramie
negative pressure
hairiness index
przędzenie kompaktowe
ramia
redukcja włochatości tkanin
Opis:
The application of the compact spinning technique with a suction groove could reduce the spinning triangle to a minimum and dramatically decrease the hairiness of ramie yarn. The change range of negative pressure was discussed when the hairiness index was reduced to a minimum for the best gathering effect. The relationship between the doffing time and hairiness index of compact yarn was studied. When the suction groove was not cleaned, the spinning times influenced the fibre number accumulated inside the suction groove. The cleaning suction groove made airflow run smoothly, and the gathering effect of fibres was basically unchanged; thus the hairiness index of yarn rarely fluctuated. For compact yarn compared with 100% 27.8 tex traditional ring-spun yarn, the 4 mm hairiness index and above decreases by more than 79.72%. The result shows that ramie compact spinning with a suction groove could gather edge fibres effectively and reduce harmful hairiness markedly.
Zastosowanie przędzenia kompaktowego z rowkiem zasysającym pomogło zredukować trójkąt przędący i w ten sposób intensywnie zmniejszyć włochatość otrzymywanych przędz. Ustalono zakres stosowania podciśnienia dla uzyskania najlepszego efektu. Kiedy rowek zasysający nie był czyszczony, czas przędzenia wpływał na ilość włókien akumulowanych wewnątrz tego rowka. Czyszczenie rowka zasysającego powoduje, że powietrze przepływa równomiernie i efekt skupienia włókien pozostawał niezmieniony dzięki czemu indeks włochatości przędzy zmieniał się w małym stopniu. Wyniki pokazały, że kompaktowe przędzenie ramii z zastosowaniem rowka zasysającego pozwala skutecznie gromadzić skrajne włókna i redukować włochatość.
Źródło:
Fibres & Textiles in Eastern Europe; 2014, 3 (105); 54-57
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ regularnej aktywności fizycznej na skład ciała i ciśnienie tętnicze dzieci ze szkoły sportowej
The influence of regular physical activity on blood pressure and body composition in children attending sports school
Autorzy:
Stańczyk, Małgorzata
Krenc, Zbigniew
Tkaczyk, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/1032997.pdf
Data publikacji:
2013
Wydawca:
Medical Communications
Tematy:
blood pressure
body composition
body mass index
children
physical activity
wysiłek fizyczny
ciśnienie tętnicze
wskaźnik masy ciała
skład ciała
dzieci
Opis:
Physical activity is considered to have influence on anthropometry and blood pressure. It is supposed that regular physical activity leads to better body composition and lowers blood pressure. The aim of the study: Evaluation of influence of regular physical activity offered by sports school on body composition and blood pressure in 14-year-old children. Material and methods: Twenty-five children from sports school participated in the study. Children were examined twice – interval was 12 months. Changes of anthropometric values, body composition and blood pressure values were analysed. Results: In whole group increase of systolic blood pressure was observed (p < 0.05), mainly in boys. Diastolic blood pressure didn’t change. Body composition changed negatively in whole group: fat mass increased (13% vs. 20%, p < 0.05), gain of fat mass was higher in girls (6% vs. 3%, p < 0.05). There was significant increase of BMI percentile in girls (37 vs. 49, p < 0.05), in boys this parameter didn’t change. Conclusion: Increased physical activity offered by sports school doesn’t improve nutritional status of 13–14-year-old girls and boys, whose body fat massincrease. School sport activity doesn’t reduce blood pressure in 13–14-year-old children, according to age standards. Centile values of boys systolic blood pressure were even higher.
Trening fizyczny uważany jest za czynnik wpływający na parametry antropometryczne i ciśnienie tętnicze. Twierdzi się, że osoby regularnie ćwiczące mają lepsze wskaźniki składu ciała oraz niższe wartości ciśnienia tętniczego krwi w porównaniu z osobami nieuprawiającymi sportu. Cel: Ocena wpływu regularnej rocznej aktywności fizycznej prowadzonej w szkole sportowej na skład ciała oraz wartości ciśnienia tętniczego u dzieci 14-letnich (II klasa gimnazjum). Materiał i metodyka: W badaniu wzięło udział 25 dzieci z gimnazjum sportowego. Dzieci badano dwukrotnie w odstępie 12 miesięcy. Analizie poddano zmianę parametrów antropometrycznych, składu ciała metodą impedancji bioelektrycznej oraz wartości ciśnienia krwi. Wyniki: W całej grupie zaobserwowano wzrost wartości centylowych ciśnienia skurczowego krwi (p < 0,05), przede wszystkim u chłopców. W zakresie ciśnienia rozkurczowego nie zanotowano istotnych różnic. Skład ciała zmienił się niekorzystnie u wszystkich badanych – wzrósł udział tłuszczu (13% vs 20%, p < 0,05), a przyrost masy tłuszczowej był wyższy u dziewczynek (6% vs 3%, p < 0,05). Centyl BMI istotnie statystycznie wzrósł w grupie dziewczynek (37 vs 49, p < 0,05), u chłopców nie uległ zmianie. Wnioski: Aktywność fizyczna proponowana przez szkołę sportową nie poprawia stanu odżywienia 13–14-letnich dziewcząt i chłopców, u których obserwuje się istotne zwiększenie w organizmie zawartości tkanki tłuszczowej. Szkolna aktywność fizyczna nie powoduje obniżenia ciśnienia tętniczego wśród młodzieży w wieku 13–14 lat w odniesieniu do norm wiekowych. W zakresie ciśnienia skurczowego w grupie chłopców zaobserwowano nawet wyższe wartości centylowe.
Źródło:
Pediatria i Medycyna Rodzinna; 2013, 9, 2; 165-172
1734-1531
2451-0742
Pojawia się w:
Pediatria i Medycyna Rodzinna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a Composite Propellant Formulation with a High Performance Index Using a Pressure Casting Technique
Autorzy:
Ramesh, K.
Jawalkar, S. N.
Sachdeva, S.
Bhattacharya, B.
Powiązania:
https://bibliotekanauki.pl/articles/358322.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
composite propellant
high density
high performance index
pressure casting
solid loading
Opis:
There is a continuous demand for high performance composite propellant formulations to meet future requirements. The performance of composite propellant formulations can be enhanced by the addition of energetic oxidizers, like ADN/HNF as well as an energetic binder & a plasticizer. However, on incorporation of energetic ingredients, the composition becomes sensitive, and thus processing, handling and transportation pose a greater threat. Therefore, a moderately high burn rate composition having a burn rate ~ 13-14 mmźs -1 at 7000 kPa was tailored by increasing the solid loading of the propellant from 85.15% to 87.27% with the help of ammonium perchlorate and process aids without affecting the burn rate and mechanical properties. The tailored composition was studied for different properties such as end of mix viscosity, density, mechanical & ballistic properties. The evaluated data reveal that the end of mix viscosity of the tailored composition is higher than the base composition, i.e., 672 Paźs and 2340 Paźs at the same temperature; however, this viscosity was castable using a pressure casting technique. The properties of the cured propellant reveal that there is an enhancement of density from 1.74 gźcm -3 to 1.79 gźcm -3 with no other changes in mechanical properties. The performance index of the tailored composition has been increased from 416 to 437, well supported by results of ballistic evaluation motors of 2 kg.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 1; 49-58
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Formulation and Validation of Muraours Linear Burning Rate Law for Solid Rocket Propellants
Autorzy:
Shekhar, H.
Powiązania:
https://bibliotekanauki.pl/articles/358152.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
rocket propellants
burning rate
pressure index
ballistics prediction
Muraour's
Opis:
Linear variation of burning rate with pressure (burning rate, r = H + Sp), referred in the literature as Muraour's law, is adopted as the burning rate law for solid rocket propellants. The two constants 'H' and 'S' are the vacuum burning rate and the slope of burning rate variation, respectively. The conventional power law of the burning rate, r = apn, is also analyzed and its practical, anomalous behaviour such as zero burning rate at zero pressure, the reduction in pressure sensitivity of the burning rate at higher pressures, the lower burning rate for the high pressure index in typical situations etc, are explained with illustrations. Like the conventional power law of burning rate, the linear burning rate law considered here is also empirical but mathematically simpler than the power law. Using burning rate and pressure data from various literature sources similar regression coefficients are observed for the conventional power law as well as for the alternative linear burning rate law. The mathematical concept for the evolution of the pressure time profile with the considered linear burning rate law is developed and validated practically with the actual firing of rocket propellants as uninhibited, tubular configurations in a ballistic evaluation motor (BEM). Close matching of the firing curve, predicted by the conventional power law and by the proposed linear burning rate law validates the mathematical formulation. The considered linear burning rate law is simple, easy to apply and gives a better representation of the burning rate behaviour of solid rocket propellants.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 4; 353-364
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on High Burning Rate Composite Propellant Formulations using TATB as Pressure Index Suppressant
Autorzy:
Mehilal, -
Jawalkar, S.
Kurva, R.
Sundaramoorthy, N.
Dombe, G.
Singh, P. P.
Bhattacharya, B.
Powiązania:
https://bibliotekanauki.pl/articles/951502.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
composite propellant
ammonium perchlorate
TATB
pressure index suppressant
Opis:
High burning rate propellant compositions are generally used in gas generators to eject missile from canister. Because of high burning rate, pressure index of the composition increases during burning. To reduce the pressure index, a high burning rate composite propellant formulations (~20 mm/s) based on AP/HTPB/Al have been prepared by incorporating TATB and studied in detail for viscosity build-up, thermal and mechanical properties, sensitivity as well as burning rate and pressure index (n). The data indicate that there is a decrease in end of mix viscosity on increasing the percentage of TATB. The same trend was also observed with mechanical properties while significant improvement in overall thermal stability was clearly observed. The sensitivity data indicate that impact and friction values show decreasing trend infer better safe to handle. The burn rate data reveal that on addition of TATB from 0.5 to 2% decrease in burning rate was not observed while on addition of further TATB up to 5% and beyond this significant decrease in burning rate was observed. The data on pressure index (n) also reveal that TATB is very effective in reducing the 'n' value up to 2% and beyond this 'n' value increases close to standard composition. The data on 'n' value reveal that it reduces from 0.47 to that of standard composition to 0.36 for the compositions containing TATB up to 2.0% in the pressure range of 60-90 kg/cm2.
Źródło:
Central European Journal of Energetic Materials; 2012, 9, 3; 237-249
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ wybranego wskaźnika jakości sterowania na parametry doju w aparatach udojowych w dojarce rurociągowej
Influence of selected control quality index on milking parameters in milking units in a milk piepeline
Autorzy:
Skalska, D.
Powiązania:
https://bibliotekanauki.pl/articles/289124.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
aparat udojowy
wskaźnik jakości sterowania
średnie podciśnienie ssania
milking unit
control quality index
average negative pressure of suction
Opis:
Analizowano wpływ wybranego wskaźnika jakości sterowania (pola powierzchni pod krzywą zmian podciśnienia w czasie trwania zakłócenia - S1) na zmiany średniego podciśnienia ssania - pss, średniego podciśnienia masażu - pms, amplitudy podciśnienia ssania - aps wahania podciśnienia w cyklu - dp po wprowadzeniu zakłócenia do rurociągu mlecznego przy pracy sześciu aparatów udojowych (o zadanych strumieniach wypływu cieczy z aparatów Qm = 2, 4, 6, 8 [l*min-1]) dla trzech cykli względem pulsacji ("1 po", "2-4 po" i "ustal"). Wykazano, że ww. parametry ciśnieniowe w aparatach udojowych zależą liniowo od zmian pola powierzchni S1 w pierwszym cyklu pulsacji (dla fazy "1 po") i w następnych trzech cyklach (dla fazy "2-4 po") dla zadanych Qm.
Influence of the selected control quality index (surface areas beneath the curve of the negative pressure fluctuations during interference S1) on fluctuations of average sucking negative pressure pss, average negative pressure of massage pms, amplitude of the sucking negative pressureaps negative pressure variations in the cycle - dp after application of interference to a milk pipeline with the work of six milking untis (of pre-set stream of liquid flow from units Qm = 2, 4, 6, 8 [l*min-1]) for three cycles in regard to pulsation ("1 po", "2 - 4 po" i "ustal"). It was specified that the abovementioned pressure parameters in milking units depend linearly on the surface area changes S1 in the first cycle of pulsation (for phase"1 po") and in the subsequent three cycles (for phase "2 - 4 po") Qm.
Źródło:
Inżynieria Rolnicza; 2011, R. 15, nr 8, 8; 237-244
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 16

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