scholarly journals Mathematical Modelling of the Entrainment Ratio of High Performance Supersonic Industrial Ejectors

Processes ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 88
Author(s):  
Dario Friso

For many years now, manufacturers have been producing supersonic ejectors with a high entrainment ratio for the chemical, oil, and food industries. In the present work, mathematical modelling of the entrainment ratio of such industrial ejectors is carried out, in which a variation of the diffuser efficiency is also assumed to be a function of the Mach number of the motive gas. To determine this unknown relationship, the mathematical modelling was overturned by inserting the entrainment ratios of ten different high-performance industrial ejectors, as identified through an experimental investigation. The mathematical modelling, completed through the use of the relationship between the diffuser efficiency and the Mach number of the motive gas, was applied to sixty-eight ejectors, built and tested experimentally over the last twenty years as part of research aimed at the development of thermal ejector refrigeration systems (ERSs), to obtain the entrainment ratios proposed by the manufacturers (industrial entrainment ratios). A comparison of the experimental entrainment ratios with respect to the industrial ones demonstrated that the former were always lower, ranging from a minimum of −17% to a maximum of −82%. These results indicate that the lab-built ejectors for ERS prototypes can be improved. Therefore, in the future, researchers should apply numerical analysis iteratively, starting from a given geometry of the ejector, and modifying it until the numerical analysis provides the industrial value of the entrainment ratio.

2013 ◽  
Vol 12 (4) ◽  
pp. 157-169 ◽  
Author(s):  
Philip L. Roth ◽  
Allen I. Huffcutt

The topic of what interviews measure has received a great deal of attention over the years. One line of research has investigated the relationship between interviews and the construct of cognitive ability. A previous meta-analysis reported an overall corrected correlation of .40 ( Huffcutt, Roth, & McDaniel, 1996 ). A more recent meta-analysis reported a noticeably lower corrected correlation of .27 ( Berry, Sackett, & Landers, 2007 ). After reviewing both meta-analyses, it appears that the two studies posed different research questions. Further, there were a number of coding judgments in Berry et al. that merit review, and there was no moderator analysis for educational versus employment interviews. As a result, we reanalyzed the work by Berry et al. and found a corrected correlation of .42 for employment interviews (.15 higher than Berry et al., a 56% increase). Further, educational interviews were associated with a corrected correlation of .21, supporting their influence as a moderator. We suggest a better estimate of the correlation between employment interviews and cognitive ability is .42, and this takes us “back to the future” in that the better overall estimate of the employment interviews – cognitive ability relationship is roughly .40. This difference has implications for what is being measured by interviews and their incremental validity.


2020 ◽  
Vol 29 (12) ◽  
pp. 52-58
Author(s):  
E.P. Meleshkina ◽  
◽  
S.N. Kolomiets ◽  
A.S. Cheskidova ◽  
◽  
...  

Objectively and reliably determined indicators of rheological properties of the dough were identified using the alveograph device to create a system of classifications of wheat and flour from it for the intended purpose in the future. The analysis of the relationship of standardized quality indicators, as well as newly developed indicators for identifying them, differentiating the quality of wheat flour for the intended purpose, i.e. for finished products. To do this, we use mathematical statistics methods.


EMJ Radiology ◽  
2020 ◽  
Author(s):  
Filippo Pesapane

Radiomics is a science that investigates a large number of features from medical images using data-characterisation algorithms, with the aim to analyse disease characteristics that are indistinguishable to the naked eye. Radiogenomics attempts to establish and examine the relationship between tumour genomic characteristics and their radiologic appearance. Although there is certainly a lot to learn from these relationships, one could ask the question: what is the practical significance of radiogenomic discoveries? This increasing interest in such applications inevitably raises numerous legal and ethical questions. In an environment such as the technology field, which changes quickly and unpredictably, regulations need to be timely in order to be relevant.  In this paper, issues that must be solved to make the future applications of this innovative technology safe and useful are analysed.


2015 ◽  
Vol 10 (2) ◽  
pp. 103-113
Author(s):  
Ewa Hajduk-Kasprowicz ◽  
Lech Nieżurawski

The paper discusses the problems of fading and ending of business relationships in the sphere of professional services i.e. the phase of a relationship dissolution resulting from a client's or a firm's decision to end it. This phase includes, among others, determining the causes of the relationship dissolution and drawing conclusions for the future in order to prevent losing the most lucrative clients. Both in theory and in practice, relationship ending is perceived as something stretched in time i.e. consisting of numerous stages and influenced by numerous factors and events.The aim of the present paper is an analysis of the modern literature on the causes and mechanisms of business relationships termination in the sphere of professional services as well as indicating some possibilities of a more effective and efficient management of these relations. 


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