scholarly journals Simulation of a Breathing Apparatus on Chemically Bound Oxygen with a Circular Pendulum Circuit of the Air Duct Part

2021 ◽  
pp. 46-52
Author(s):  
S.G. Ekhilevskiy ◽  
◽  
O.V. Golubeva ◽  
E.P. Potapenko ◽  
◽  
...  
Keyword(s):  
Maximum Permissible Concentration ◽  
Protective Action ◽  
Dead Layer ◽  
Respiratory Protection ◽  
Sorbent Layer ◽  
Breathing Resistance ◽  
Breathing Apparatus ◽  
Short Period ◽  
The Dead ◽  
Made In

At present, the main prospects for improving the insulating means of respiratory protection are associated with the chemical method of oxygen reservation. The arguments in favor of this choice are the high packing density of oxygen and its self-regulating supply, depending on the physical activity of a person. The main schemes of the air duct part of breathing apparatus on chemically bound oxygen are circular and pendulum. The attempt is made in the article to combine the advantages of the circular (small harmful space) and pendulum (small volume of the dead layer) schemes of breathing apparatus on chemically bound oxygen. For these purposes, the formalism method was developed, which allows mathematically and with the help of a computer to simulate the dynamic sorption activity of the regenerative cartridge of a breathing apparatus with a hybrid (circular-pendulum) scheme of the air duct part. The increase in the protective action of the apparatus is determined due to the use of the resource of the dead sorbent layer in the result of the air flow reverse in the pendulum part of the regenerative cartridge. Feasibility of using a hybrid scheme in the self-rescuers with a short period of protective action is shown. The optimal length of the pendulum part is determined, at which the breathing resistance decreases, and the harmful space occupied by the air returning for inhalation without contact with the unreacted layers of the oxygen-containing product is not increased. Its weak dependence on the total length of the regenerative cartridge and the maximum permissible concentration of carbon dioxide in the air returning to inhalation is shown, which makes the circular pendulum scheme realizable in practice.

scholarly journals Optimization of the thermal regime of the insulating breathing apparatus on chemically bound oxygen

2021 ◽  
Vol 66 (1) ◽  
pp. 101-109
Author(s):  
S. G. Ekhilevskiy ◽  
E. P. Potapenko
Keyword(s):  
Numerical Experiments ◽  
Dead Layer ◽  
Technical Solution ◽  
Respiratory Protection ◽  
Heat Sources ◽  
Breathing Apparatus ◽  
Air Stream ◽  
Exhaled Air ◽  
Flow Filtration ◽  
Slow Filtration

It is proved that the main prospects for improving the insulating means of respiratory protection are related to the chemical method of oxygen reservation. To increase the efficiency of its use, it is necessary to use the resource of the dead layer of the chemosorbent and prevent the sintering of the granules of the oxygen-containing product under the action of exothermic heat. This is achieved by faster pulsed passage of exhaled air through the frontal layers of the chemosorbent and its slow filtration through the rest of the regenerative cartridge. To evaluate the effectiveness of such a technical solution, a mathematical model of air regeneration in an insulating breathing apparatus with an uneven rate of exhalation filtration through a regenerative cartridge is constructed. The dependencies on the time and coordinate of the concentration of CO2 molecules in the air stream and the share of the use of the protective resource of the regenerative cartridge are obtained. Using numerical experiments, the optimal coordinate of the air flow filtration rate jump was determined to prevent sintering of the granules. Depending on the amount of pressure damping on exhalation and inspiration for the RHS respirator, an increase in the protective effect of the device was determined and a decrease in the power of exothermic heat sources in the frontal layers of the oxygen-containing product was calculated. The results obtained confirm the effectiveness of the considered improvements of the design, which make it possible to increase the reliability of insulating breathing apparatus on chemically bound oxygen and to increase the efficiency of using their protective resource.

Investigation of Dead Layer Thickness in SrRuO3/Ba0.5Sr0.5TiO3/Au Thin Film Capacitors

2000 ◽  
Vol 655 ◽  
Author(s):  
L. J. Sinnamon ◽  
R. M. Bowman ◽  
J. M. Gregg
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Layer Thickness ◽  
Perovskite Phase ◽  
Frequency Dispersion ◽  
Dead Layer ◽  
Parameter Ratio ◽  
Thin Film Capacitors ◽  
Dead Layer Thickness ◽  
The Dead

AbstractThin film capacitors with barium strontium titanate (BST) dielectric layers of 7.5 to 950 nm were fabricated by Pulsed Laser Deposition. XRD and EDX analyses confirmed a strongly oriented BST cubic perovskite phase with the desired cation stoichiometry. Room temperature frequency dispersion (ε100 kHz / ε100 Hz) for all capacitors was greater than 0.75. Absolute values for the dielectric constant were slightly lower than expected. This was attributed to the use of Au top electrodes since the same sample showed up to a threefold increase in dielectric constant when Pt was used in place of Au. Dielectric constant as a function of thicknesses greater than 70 nm, was fitted using the series capacitor model. The large interfacial parameter ratio di / εi of 0.40 ± 0.05 nm implied a significant dead-layer component within the capacitor structure. Modelled consideration of the dielectric behaviour for BST films, whose total thickness was below that of the dead layer, predicted anomalies in the plots of d/ ε against d at the dead layer thickness. For the SRO/BST/Au system studied, no anomaly was observed. Therefore, either (i) 7.5 nm is an upper limit for the total dead layer thickness in this system, or (ii) dielectric collapse is not associated with a distinct interfacial dead layer, and is instead due to a through-film effect.

Measurements of the dead layer in superfluid4He films on H3 and C60

1994 ◽  
Vol 194-196 ◽  
pp. 619-620
Author(s):  
P.W. Adams ◽  
V. Pant ◽  
A.F. Hebard
Keyword(s):  
Dead Layer ◽  
The Dead

INFANT FEEDING PRACTICES IN ISRAEL

PEDIATRICS ◽  
1960 ◽  
Vol 26 (2) ◽  
pp. 321-330
Author(s):  
Jenny Thaustein ◽  
Haim Shalom Halevi ◽  
George Mundel
Keyword(s):  
Breast Feeding ◽  
Complementary Feeding ◽  
Complementary Food ◽  
Healthy Development ◽  
Quantitative Measurements ◽  
Short Period ◽  
Second Year ◽  
Breast Fed ◽  
Made In ◽  
The Way

Almost 100% of mothers in Israel, irrespective of their cultural background, start breast feeding their infants. This is in accordance with the accepted policy of the medical and nursing professions in Israel. Complete breast feeding is continued only for a relatively short period. At the end of the second month of life, half the infants already receive complementary food, and only 5% are exclusively breast-fed during their fifth month. Partial breast feeding is continued in 50% of the infants until the ninth month, and for a small fraction of the sample (mainly Sepharadim and Arabs) this continues until the middle of the second year of life. The complementary food contains all the essential nutrients for the healthy development of infants, although no quantitative measurements were made in this study. The intakes of protein supplement and vitamins A and D lag behind the recommended schedules, especially among the groups of oriental origin. There are no striking differences in the pattern of feeding and weaning in the various groups. Apparently the different patterns of feeding "imported" by immigrants from the various countries rapidly become integrated in Israel; there is an impression that a national pattern is evolving. The guidance given by the preventive services for mothers is particularly instrumental in this direction. This guidance is especially evident in the way complementary feeding is introduced and in the way the decision on weaning is made.

THE PEDIATRICIAN AND THE PUBLIC

PEDIATRICS ◽  
1955 ◽  
Vol 15 (4) ◽  
pp. 479-487
Author(s):  
John A. Askin ◽  
Kurt Glaser
Keyword(s):  
World War Ii ◽  
World War I ◽  
Old Testament ◽  
Jewish People ◽  
Jewish State ◽  
World War ◽  
The Public ◽  
Short Period ◽  
State Of Israel ◽  
Made In

IN SPITE of a short period of sovereignty— less than 7 years—the State of Israel is playing an important role in matters pertaining not only to the Middle East but, in some respects, in matters of importance to the whole world. In medicine the advances in Israel have been no less striking than the progress made in other fields. It is felt that the pediatricians of our country might be interested to learn about Israel's medical status, particularly pertaining to pediatrics. Palestine, of which the present Israel is a part, was in Old Testament times known as Canaan or Philistia because of the tribes which lived there. Palestine was the home of the Jewish people from the time Joshua conquered the land, about 1400 B.C., until the Romans destroyed the Jewish State in the year 70 A.D. Around 630 A.D. the country came under Moslem power. From 1516 to the end of World War I Palestine was a part of the Turkish Empire. In 1917, the British Government issued the famous Balfour Declaration which promised the Jews of the world that they could build a national homeland in Palestine. The League of Nations made the land a British mandate in 1920. From then until World War II Palestine was at several occasions plunged into violent civil war between the Jews and the Arabs. After World War II in 1947 Great Britain announced a decision to give up the Mandate.

scholarly journals Mortars with CDW Recycled Aggregates Submitted to High Levels of CO2

2021 ◽  
Vol 6 (11) ◽  
pp. 159
Author(s):  
Ricardo Infante Gomes ◽  
David Bastos ◽  
Catarina Brazão Farinha ◽  
Cinthia Maia Pederneiras ◽  
Rosário Veiga ◽  
...  
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Construction Materials ◽  
Environmental Benefits ◽  
Recycled Aggregates ◽  
Construction And Demolition Wastes ◽  
Short Period ◽  
Natural Aggregates ◽  
Cement Factories ◽  
Made In

Construction and demolition wastes (CDW) are generated at a large scale and have a diversified potential in the construction sector. The replacement of natural aggregates (NA) with CDW recycled aggregates (RA) in construction materials, such as mortars, has several environmental benefits, such as the reduction in the natural resources used in these products and simultaneous prevention of waste landfill. Complementarily, CDW have the potential to capture CO2 since some of their components may carbonate, which also contributes to a decrease in global warming potential. The main objective of this research is to evaluate the influence of the exposure of CDW RA to CO2 produced in cement factories and its effect on mortars. Several mortars were developed with a volumetric ratio of 1:4 (cement: aggregate), with NA (reference mortar), CDW RA and CDW RA exposed to high levels of CO2 (CRA). The two types of waste aggregate were incorporated, replacing NA at 50% and 100% (in volume). The mortars with NA and non-carbonated RA and CRA from CDW were analysed, accounting for their performance in the fresh and hardened states in terms of workability, mechanical behaviour and water absorption by capillarity. It was concluded that mortars with CDW (both CRA and non-carbonated RA) generally present a good performance for non-structural purposes, although they suffer a moderate decrease in mechanical performance when NA is replaced with RA. Additionally, small improvements were found in the performance of the aggregates and mortars with CRA subjected to a CO2 curing for a short period (5 h), while a long carbonation period (5 d) led to a decrease in performance, contrary to the results obtained in the literature that indicate a significant increase in such characteristics. This difference could be because the literature focused on made-in-laboratory CDW aggregates, while, in this research, the wastes came from real demolition activities, and were thus older and more heterogeneous.

scholarly journals Resurrected from the dead: Full characterization of an old HPGe detector using γ-ray and CT tomographies coupled to standard calibration techniques and simulations

2019 ◽  
Vol 24 ◽  
pp. 174
Author(s):  
V. Angelopoulou ◽  
E. Kouvaris ◽  
V. Lagaki ◽  
T. J. Mertzimekis ◽  
P. Papagiannis
Keyword(s):  
Hpge Detector ◽  
Bulk Sample ◽  
Dead Layer ◽  
Operational Mode ◽  
Ct Scanner ◽  
Environmental Radiation ◽  
Full Characterization ◽  
Technical Specifications ◽  
Γ Ray ◽  
The Dead

A decommissioned co-axial HPGe detector has been recently acquired and returned to operational mode in an effort to build an environmental radiation spectrometer at the University of Athens. The new counting station, GEROS (Germanium for Environmental RadiOactivity Studies), was fully characterized prior to operation to obtain detailed information on its linear response, efficiency and energy resolution. In addition to using point-like calibration sources (60Co,137Cs,152Eu and 226Ra), several bulk sample geometries were calibrated by means of an IAEA standard, focusing on soils, sediments and solid materials. In lieu of deteailed technical specifications, the crystal integrity, especially in regards to the dead layer known to build up over the years was studied by means of γ-ray tomography. The 3D geometry of the crystal was fully reconstructed considering the absorption coefficients, and the dead layer thickness was estimated. The overall crystal alignment inside the case was also checked. The results were verified by placing GEROS inside a medical CT scanner and irradiating it to obtain detailed longitudinal and transverse sections. The results were combined to provide input data for subsequent MCNP5 simulations. Good overall agreement between simulations and measurements was achieved. Despite some expected loss of resolution, the detector was found to perform substantially well.

scholarly journals Extent of Adoption of Recommended Poultry Farming Practices by the Farmers

2021 ◽  
Vol 10 (9) ◽  
pp. 38-53
Author(s):  
Hanuman Sahay Bunkar G. S. Bangarwa
Keyword(s):  
National Income ◽  
Poultry Production ◽  
Farming Practices ◽  
Poultry Industry ◽  
Self Employment ◽  
Short Period ◽  
Production Programme ◽  
The Government ◽  
Made In ◽  
Poultry Farming

The poultry production in our country has made a significant progress over the years due to research and development thrust of the government and organized private sector. Poultry farming is considered as an important tool for self-employment as it offers vast scope for generating income in socially and economically backward areas. No other livestock production programme in our country has made as much progress in a short period as the poultry sector has made. The revolutionary changes made in poultry industry in the last four decades is a matter of great pride. The poultry sector provides livelihood to nearly one lakh farmers and contributes to a great extent to the national income. In Rajasthan, poultry industry is a live segment and source of revenue to the government. In the last five decades, Jaipur region has made manifold progress in the development of the poultry sector. Jaipur district is one such districts which has made a great headway in the promotion of poultry sector. With more than 14889 organized poultry farms, it has engaged more than 45000 people directly or indirectly.

Sign in / Sign up

Export Citation Format

Share Document