scholarly journals Analysis of pressure difference changes in respirator filters while dusting

2018 ◽  
Vol 60 ◽  
pp. 00012 ◽  
Author(s):  
Serhii Cheberiachko ◽  
Olena Yavorska ◽  
Yurii Cheberiachko ◽  
Andrii Yavorskyi
Keyword(s):  
Pressure Difference ◽  
System Analysis ◽  
Aerosol Particles ◽  
Protective Efficiency ◽  
Final Time ◽  
Protection Level ◽  
Filter Model ◽  
Working Zone ◽  
Nonstationary Filtration ◽  
Protection Period

Objective is to determine the relation between pressure difference of a filter and parameters of a filtering layer to lengthen the protection period. The study involved elements of system analysis and mathematical modeling. Basic statements of the theory of nonstationary filtration and aerohydrodynamics were applied to develop a dust-loaded filter model. Dependence of pressure difference in a filter upon certain changes in packaging density of dust-loaded fibers has been determined; the dependence makes it possible to define minimum fiber packaging density to provide maximum dust capacity. To provide maximum dust capacity and high protective efficiency, the number of filtering layers in multilayered filters depends upon dust concentration within the air of the working zone, specified protection level of a respirator, air loss, and maximum dust volume which may be accumulated in the finishing filtering layer in terms of fiber packaging density being determined according to the minimum pressure difference in a filter at final time of respirator operation. A model of changes in pressure difference in filtering respirators in the process of aerosol particles depositing on filters has been improved; contrary to other available models, that one takes into consideration changes in fiber packaging density while dusting, filtration coefficient, and the amount of aerosol particles.

scholarly journals Development of a standardized method for the evaluation of the microbial protective efficiency of cosmetic packaging

2020 ◽  
Author(s):  
Chloe Catovic ◽  
Sylvia Martin ◽  
Sephane Desaint ◽  
Christine Borges ◽  
Helene Lesouhaitier ◽  
...  
Keyword(s):  
Adverse Effects ◽  
Microbial Contamination ◽  
Protective Efficiency ◽  
Protection Level ◽  
Low Level ◽  
Cosmetic Product ◽  
The Right ◽  
Different Origins ◽  
Preservative Free

Abstract The doubt regarding adverse effects of antimicrobial preservative, has modified the demand by the consumers which impose more and more the production of low-level and even preservative free cosmetics. In these products, protection against microbial contamination is therefore devoted to the packaging. This have prompted the emergence of a great diversity of so called “protective”, “overprotective” and “barrier” packaging, but this designation is not normalized and the choice of the right packaging adapted to each cosmetic product remains essentially empirical, hazardous and time consuming. The cluster Cosmetic Valleys decided to launch a commission aimed at defining a complete and experimentally validated method allowing to classify the microbiological protection level of cosmetic packaging. As reported herein, this was requiring the development a specific bacteriostatic medium usable over 7 days and an in vitro procedure reproducing in-use contamination and consumer gesture. On the basis of tests realized over 800 packs of different origins and performances, a classification in six grades was proposed in order to distinguish the protective efficiency of cosmetic packaging. This work can be considered is a first step towards a regulatory text.

Work system analysis of home nursing care and implications for medication errors

2005 ◽  
Author(s):  
K. L. Calvin ◽  
Gail R. Casper ◽  
Ben-Tzion Karsh ◽  
Patricia F. Brennan ◽  
Laura J. Burke ◽  
...  
Keyword(s):  
Medication Errors ◽  
Nursing Care ◽  
System Analysis ◽  
Home Nursing ◽  
Work System ◽  
Home Nursing Care

Dependence of Blood Clot Lysis on the Mode of Transport of Urokinase into the Clot - A Magnetic Resonance Imaging Study in Vitro

1991 ◽  
Vol 65 (05) ◽  
pp. 549-552 ◽  
Author(s):  
A Blinc ◽  
G Planinšič ◽  
D Keber ◽  
O Jarh ◽  
G Lahajnar ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pressure Difference ◽  
Volume Flow Rate ◽  
Blood Clot ◽  
Linear Regression Analysis ◽  
Imaging Study ◽  
Clot Lysis ◽  
Resonance Imaging

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.

An experience of elaboration and implementation of systems of slag-forming mixtures mechanized feeding into CCM moulds

2020 ◽  
Vol 76 (10) ◽  
pp. 994-1003
Author(s):  
S. P. Eron’ko ◽  
M. Yu. Tkachev ◽  
E. V. Oshovskaya ◽  
B. I. Starodubtsev ◽  
S. V. Mechik
Keyword(s):  
Economic Effect ◽  
Three Dimensional ◽  
Movable Part ◽  
High Quality ◽  
Working Zone ◽  
Fine Material ◽  
Mixing Chamber ◽  
Field Samples ◽  
Technical Solutions ◽  
Feeding Systems

Effective application of slag-forming mixtures (SFM), being fed into continuous castingg machine (CCM) moulds, depends on their even distribution on the melt surface. Manual feeding of the SFM which is widely usedd does not provide this condition, resulting in the necessity to actualize the work to elaborate systems of SFM mechanized feedingg into moulds of various types CCM. A concept of the designing of a system of SFM feeding into CCM moulds presented with the ratte strictly correspondent to the casting speed and providing formation of an even layer of fine material of given thickness on the whoole surface of liquid steel. The proposed methods of designing of the SFM mechanized feeding systems based on three-dimensional computer simulation with the subsequent verification of the correctness of the adopted technical solutions on field samples. Informattion is presented on the design features of the adjusted facilities intended for continuous supply of finely granulated and powder mixtuures on metal mirror in moulds at the production of high-quality billets, blooms and slabs. Variants of mechanical and pneumo-mechaanical SFM supply elaborated. At the mechanical supply the fine material from the feeding hopper is moved at a adjusted distance bby a rigid horizontally located screw. At the pneumo-mechanical supply the metered doze of the granular mixture is delivered by a sshort vertical screw, the lower part of which is located in the mixing chamber attached from below to the hopper and equipped with ann ejector serving for pneumatic supply of the SFM in a stream of transporting gas. It was proposed to use flexible spiral screws in the ffuture facilities of mechanical SFM feeding. It will enable to eliminate the restrictions stipulated by the lack of free surface for locatiion of the facility in the working zone of the tundish, as well as to decrease significantly the mass of its movable part and to decreaase the necessary power of the carriage moving mechanism driver. The novelty of the proposed technical solutions is protected by thhree patents. The reduction of 10–15% in the consumption of slag-forming mixtures during the transition from manual to mechanizeed feeding confirmed. The resulting economic effect from the implementation of technical development enables to recoup the costs inncurred within 8–10 months.

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