Atomization of Liquids by Means of a Rotating Cup

1950 ◽  
Vol 17 (2) ◽  
pp. 145-153 ◽  
Author(s):  
J. O. Hinze ◽  
H. Milborn

Abstract Liquid, supplied through a stationary tube to the inner part of a rotating cup widening toward a brim, flows viscously in a thin layer toward this brim and is then flung off, all by centrifugal action. The flow within this layer and the disintegration phenomena occurring beyond the brim have been studied, experimentally as well as theoretically. A formula has been derived for the thickness and for the radial velocity of the liquid layer within the cup, which proved to agree reasonably well with experimental results. Three essentially different types of disintegration may take place around and beyond the edge of the cup designated, respectively, by: (a) the state of direct drop formation; (b) the state of ligament formation; and (c) the state of film formation. Which one of these is realized depends upon working conditions. Transition from state (a) into (b), or of state (b) into state (c) is promoted by an increased quantity of supply, an increased angular speed, a decreased diameter of the cup, an increased density, an increased viscosity, and a decreased surface tension of the liquid. The experimental results have been expressed in relationships between relevant dimensionless groups. For the state of ligament formation a semiempirical relationship has been derived between the number of ligaments and dimensionless groups determining the working conditions of the cup. Results of drop-size measurements made for the state of ligament formation as well as for the state of film formation show that atomization by mere rotation of the cup is much more uniform than commonly achieved with pressure atomizers.

Author(s):  
K Olejarczyk ◽  
M Wikło ◽  
K Kołodziejczyk

A comparative study of a cycloidal gearbox working with a different kind of bearings is presented in the article. Two kinds of the bearings used in the cycloidal gearbox are taken into consideration: sleeves and needle bearings. The theoretical efficiency calculation for both types of the bearing was compared with experimental results. The experiment was performed on a one-stage cycloidal gearbox designed, calculated, and manufactured during the research. The test was made under different working conditions, input speeds, and the braking torques. The results show an increase in the efficiency for the needle bearings compared to sleeves. The value of the efficiency is strictly connected with the braking torque of the gearbox as well as with the velocity. The article shows a very good correlation between calculated efficiency and the efficiency determined during the tests.


Author(s):  
M. A. Fesenko ◽  
E. V. Zueva ◽  
E. V. Fedorova

The possibility of using the survey as an intermediate stage of assessing the state of working conditions and health of workers. It is concluded that this method is not applicable as an independent device but can be used with other methods of medical research.


2015 ◽  
Vol 66 (1) ◽  
pp. 43-52
Author(s):  
Katalin Nagyváradi ◽  
Zsuzsa Mátrai

AbstractSeveral research works in the related international literature on sociology and health sciences deal with the state of health in one selected population. In these studies, the chosen sample is often connected with special jobs, especially with healthcare professionals and their working conditions. These studies predominantly examine the self-rated subjective health status using questionnaires. There are others that assess the state of health based not only on self-rated subjective indicators, but also using objective data gained by measuring. Considering the international experiences, we chose a special population in our research – healthcare professionals working in an institute for chronically ill psychiatric patients. Our choice was influenced by the fact that we wanted to include their unique working conditions when exploring and assessing their health status. Moreover, our approach was to assess the objective state of health alongside the subjective factors, as our hypothesis was that the majority of the indicators presumably coincided. The data were collected with the help of three questionnaires and some indicators of the objective health statuses were measured. The findings were processed using the SPSS 17.0 mathematical-statistical software package. Following the descriptive statistics, we applied hierarchic cluster-analysis based on results of the WHOQOLD-BREF26 life-quality questionnaire, the WHO WBI-5 Well Being Index, and on the body composition analysis. The results show the objective and subjective health status of population and the factors that influenced it; the working conditions and the interpersonal contacts in the workplace. The conclusion was that in the examined population the subjective and objective health status doesn’t coincide.


1977 ◽  
Vol 79 (1) ◽  
pp. 133-140 ◽  
Author(s):  
H. M. Meddick

SUMMARYThe ability of six different types of contamination control mats currently in use at the entrances to theatre suites and other clean areas to remove bacteria-carrying particles from theatre trolley wheels was compared. Marked differences in the effectiveness of this property were obtained; and all mats showed some disadvantages. Modification of one of the mats has resulted in improved efficiency under working conditions.


Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 741
Author(s):  
Yuseok Ban ◽  
Kyungjae Lee

Many researchers have suggested improving the retention of a user in the digital platform using a recommender system. Recent studies show that there are many potential ways to assist users to find interesting items, other than high-precision rating predictions. In this paper, we study how the diverse types of information suggested to a user can influence their behavior. The types have been divided into visual information, evaluative information, categorial information, and narrational information. Based on our experimental results, we analyze how different types of supplementary information affect the performance of a recommender in terms of encouraging users to click more items or spend more time in the digital platform.


2021 ◽  
pp. 146394912110101
Author(s):  
Geraldine Mooney Simmie ◽  
Dawn Murphy

The last decade has revealed a global (re)configuring of the relationships between the state, society and educational settings in the direction of systems of performance management. In this article, the authors conduct a critical feminist inquiry into this changing relationship in relation to the professionalisation of early childhood education and care practitioners in Ireland, with a focus on dilemmatic contradictions between the policy reform ensemble and practitioners’ reported working conditions in a doctoral study. The critique draws from the politics of power and education, and gendered and classed subjectivities, and allows the authors to theorise early childhood education and care professionalisation in alternative emancipatory ways for democratic pedagogy rather than a limited performativity. The findings reveal the state (re)configured as a central command centre with an over-reliance on surveillance, alongside deficits of responsibility for public interest values in relation to the working conditions of early childhood education and care workers, who are mostly part-time ‘pink-collar’ women workers in precarious roles. The study has implications that go beyond Ireland for the professionalisation of early childhood education and care workers and meeting the early developmental needs of young children.


2011 ◽  
Vol 11 (02) ◽  
pp. 215-236 ◽  
Author(s):  
MATTEO BROGGI ◽  
ADRIANO CALVI ◽  
GERHART I. SCHUËLLER

Cylindrical shells under axial compression are susceptible to buckling and hence require the development of enhanced underlying mathematical models in order to accurately predict the buckling load. Imperfections of the geometry of the cylinders may cause a drastic decrease of the buckling load and give rise to the need of advanced techniques in order to consider these imperfections in a buckling analysis. A deterministic buckling analysis is based on the use of the so-called knockdown factors, which specifies the reduction of the buckling load of the perfect shell in order to account for the inherent uncertainties in the geometry. In this paper, it is shown that these knockdown factors are overly conservative and that the fields of probability and statistics provide a mathematical vehicle for realistically modeling the imperfections. Furthermore, the influence of different types of imperfection on the buckling load are examined and validated with experimental results.


1979 ◽  
Vol 57 (4) ◽  
pp. 400-403 ◽  
Author(s):  
Anne Le Narvor ◽  
Pierre Saumagne

The ir spectra of mixtures of methyl propionate/water and methyl propionate/Ba2+ in dimethylsulfoxide and in acetonitrile have been recorded in the region of the νCO mode of the ester. Evidence is presented to indicate the presence of different types of complexes; their concentration was determined as a function of the composition of the medium. The spectroscopic results are compared to those from the kinetics of the alkaline hydrolysis in the same conditions. It is demonstrated that the orbital control explains the experimental results better than does the charge density on the carbon of the carbonyl group. [Journal translation]


Author(s):  
A.Yu. Svetlakova ◽  
◽  
T.T. Kaverzneva ◽  

Often, the employers allocate funds for occupational safety on the residual principle without considering the real needs in creating safe working conditions for the employees. This is especially topical for the small and medium-sized enterprises, whose budget, as a rule, does not allow to allocate sufficient funds for occupational safety. The substantiation is given concerning the need to improve modern systems for assessing the state of working conditions by integrating the missing elements, which are part of similar systems, selected during the analysis of domestic and foreign studies. In the critical review of foreign publications in the field of assessing the state of working conditions, the tools developed over the past 15 years are considered. The lines of business are selected related to the improvement of system for assessing the state of working conditions at the small and medium-sized Russian enterprises. To determine the most optimal methods, an algorithm is proposed for selecting the tools to assess the state of working conditions based on determining the efficiency parameter corresponding to each tool. Modern Russian methods are assessed in a similar way. As a result of the study, two tools for assessing the state of working conditions that are most optimal for small and medium-sized enterprises are selected. The analysis showed that the first selected method allows to assess the state of the personnel working conditions, i.e., gives a subjective assessment. The second method serves for an objective study of the estimated parameters, as well as for assessing the level of occupational hazard. Combined use of both tools can become the basis for the formation of a methodology for a comprehensive assessment of the state of working conditions at the small and medium-sized enterprises.


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