scholarly journals Thermodynamic efficiency evaluation of a low pressure turbo expander cryogenic cycle based on exergy analysis

2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 2097-2106
Author(s):  
Chowdhury Roy ◽  
Nathuram Chakraborty ◽  
Swapan Sarkar

Thermodynamic analysis, using the exergy or entropy methods, is usually carried out for better insight into the physical meaning of the losses encountered in a cryogenic plant. From the results of such analysis, it is possible to evaluate the individual efficiencies of the various processes and to identify those calling for an improvement. It is also possible to determine thermodynamic efficiency of the cycle as a whole. The technique involves determination of entropy changes or exergetic losses in each of the processes making up the cycle. Based on the exergy analysis, it has been possible to evaluate specific work requirement, overall thermodynamic efficiency, Specific cooling capacity, work requirement per kg of liquid nitrogen product and coefficient of performance of the turbo expander cryogenic cycle using hydrogen and helium as the refrigerant.

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Hüseyin Kaya ◽  
Fahrettin Günver ◽  
Onuralp Uluer ◽  
Volkan Kırmacı

An experimental analysis for parallel connected two identical counter flow Ranque–Hilsch vortex tubes (RHVT) with different nozzle materials and numbers was conducted by using compressed air as a working fluid in this paper. Heating and cooling performance of vortex tube system (circuit) and the results of exergy analysis are researched comprehensively according to different inlet pressure, nozzle numbers, and materials. Nozzles made of polyamide plastic, aluminum, and brass were mounted into the vortex tubes individually for each case of experimental investigation with the numbers of nozzles 2, 3, 4, 5, and 6. The range of operated inlet pressure 150–550 kPa with 50 kPa variation. The ratio of length–diameter (L/D) of each vortex tube in the circuit is 14 and the cold mass fraction is 0.36. Coefficient of performance (COP) values, heating, and cooling capacity of the parallel connected RHVT system were evaluated. Further, an exergy analysis was carried out to evaluate the energy losses and second law efficiency of the vortex tube circuit. The greatest thermal performance was obtained with aluminum-six-nozzle when taking into account all parameters such as temperature difference, COP values, heating and cooling capacity, and exergy analysis.


1987 ◽  
Vol 81 (3) ◽  
pp. 118-119
Author(s):  
B. Wouters

Patients who are visually impaired because of brain damage often show a visuospatial syndrome characterized by disturbances of spatial orientation and determined behavior. The lesion may be located in the frontal cortex or in the right parietal cortex of the brain; recent research shows that the determination of spatial behavior is impaired. Emphasis in the rehabilitation of these patients should be shifted from perceptual to performance orientation. It is essential for the individual to gain insight into his or her specific impairment and for the professional to work cooperatively using the patient's own strategies.


1970 ◽  
Vol 6 (1) ◽  
pp. 184-193
Author(s):  
Ольга Віговська

У статті теоретично обґрунтовано феномен конструктивного самозбереження особистості як ознаки самоактуалізації, розкриття власного потенціалу і побудови перспективи розвитку особистості та емпірично виявлено ознаки психологічної детермінації домінуючого інстинкту у конструктивній самореалізації жінок з різним соціальним статусом. Зазначено, що проблема самозбереження асоціюється з особливостями прояву інстинкту самозбереження людини, але потреби вищого порядку зумовлюють соціальну природу її поведінки, яка локалізована у найвищій точці самореалізації. Теоретично обгрунтовано, що самореалізація визначає тенденцію раціональної організації життя людини та проявляється у її почутті задоволеністю життям. З’ясовано, що психологічну основу конструктивного самозбереження становлять індивідуально-типологічні характеристики людини, які відображають психофізіологічні та психосоціальні резерви самореалізації особистості. Розроблена програма емпіричного дослідження, а також комплекс використаних методів математичної обробки результатів дослідження дає змогу конкретизувати психологічний зміст детермінації домінуючого інстинкту у конструктивній самореалізації жінок вікового діапазону 35-45 років та з різним соціальним статусом. У жінок, які виховують проблемну (хвору) дитину, домінує інстинкт "егофільного типу", що виражається у їх надмірному егоцентризмі і супроводжується низькими показниками самоактуалізації, на відміну від досліджуваних жінок, які виховують здорових дітей і у яких на фоні вираженої тенденції до самоактуалізації домінує базовий інстинкт "дослідницького типу" та "лібертофільного типу". This article theoretically proves constructive phenomenon of self identity as signs of self-disclosure own potential and prospects of development of individual construction. In addition, it empirically showes signs of psychological determination of the dominant instinct in a constructive self-determination of women with different social statuses. It was noted that the issue of self-preservation is associated with the peculiarities of manifestation of self-preservation instinct of man, but it needs higher-order cause social nature of the behavior that is localized at the highest point of self-realization. It theorized that self-realization determines the trend of rational organization of human life and manifests itself in its sense of life satisfaction. It was found that the psychological basis of constructive self-preservation of the individual make individually-typological characteristics of a person that reflect physiological and psychosocial reserves of self-realization. The developed program of empirical research, as well as the methods used complex mathematical processing of results of research allows to specify the content of the psychological determination of the dominant instinct of constructive self-realization а women age range of 35-45 years and with different social status. Women who bring up the problem child dominates the instinct of self-preservation, which is reflected in their excessive self-centeredness, and is accompanied by low levels of self-actualization, as opposed to the study of women who are raising healthy children and that against the backdrop of a pronounced tendency to self-actualization, dominated by basic instinct "research type" and "independent type."


Author(s):  
O. Yu. Atkov ◽  
S. G. Gorokhova

The individual dynamics of the allostatic load index was revealed mainly due to changes in the glucose level, body mass index, which makes it applicable for assessing the short-term adaptation to the stay in the conditions of shift work


Author(s):  
Irina Mordous

The development of modern civilization attests to its decisive role in the progressive development of institutions. They identified the difference between Western civilization and the rest of the world. Confirmation of the institutional advantages of the West was its early industrialization. The genesis and formation of institutionalism in its ideological and conceptualmethodological orientation occurs as a process alternative to neoclassic in the context of world heterodoxia, which quickly spread in social science. Highlighting institutional education as a separate area of sociocultural activity is determined by the factor of differentiation of institutional theory as a whole. A feature of institutional education is its orientation toward the individual and his/her transformation into a personality. The content of institutional education is revealed through the analysis of the institution, which includes a set of established customs, traditions, ways of thinking, behavioral stereotypes of individuals and social groups. The dynamics of socio-political, economic transformations in Ukraine requires a review of the foundations of national education and determination of the prospects for its development in the 21st century in the context of institutionalism.


Author(s):  
Andrew M. Yuengert

Although most economists are skeptical of or puzzled by the Catholic concept of the common good, a rejection of the economic approach as inimical to the common good would be hasty and counterproductive. Economic analysis can enrich the common good tradition in four ways. First, economics embodies a deep respect for economic agency and for the effects of policy and institutions on individual agents. Second, economics offers a rich literature on the nature of unplanned order and how it might be shaped by policy. Third, economics offers insight into the public and private provision of various kinds of goods (private, public, common pool resources). Fourth, recent work on the development and logic of institutions and norms emphasizes sustainability rooted in the good of the individual.


Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4842
Author(s):  
Waldemar Kamiński

Nowadays, hydrostatic levelling is a widely used method for the vertical displacements’ determinations of objects such as bridges, viaducts, wharfs, tunnels, high buildings, historical buildings, special engineering objects (e.g., synchrotron), sports and entertainment halls. The measurements’ sensors implemented in the hydrostatic levelling systems (HLSs) consist of the reference sensor (RS) and sensors located on the controlled points (CPs). The reference sensor is the one that is placed at the point that (in theoretical assumptions) is not a subject to vertical displacements and the displacements of controlled points are determined according to its height. The hydrostatic levelling rule comes from the Bernoulli’s law. While using the Bernoulli’s principle in hydrostatic levelling, the following components have to be taken into account: atmospheric pressure, force of gravity, density of liquid used in sensors places at CPs. The parameters mentioned above are determined with some mean errors that influence on the accuracy assessment of vertical displacements. In the subject’s literature, there are some works describing the individual accuracy analyses of the components mentioned above. In this paper, the author proposes the concept of comprehensive determination of mean error of vertical displacement (of each CPs), calculated from the mean errors’ values of components dedicated for specific HLS. The formulas of covariances’ matrix were derived and they enable to make the accuracy assessment of the calculations’ results. The author also presented the subject of modelling of vertical displacements’ gained values. The dependences, enabling to conduct the statistic tests of received model’s parameters, were implemented. The conducted tests make it possible to verify the correctness of used theoretical models of the examined object treated as the rigid body. The practical analyses were conducted for two simulated variants of sensors’ connections in HLS. Variant no. I is the sensors’ serial connection. Variant no. II relies on the connection of each CPs with the reference sensor. The calculations’ results show that more detailed value estimations of the vertical displacements can be obtained using variant no. II.


Author(s):  
CP Jawahar

This paper presents the energy analysis of a triple effect absorption compression (hybrid) cycle employing ammonia water as working fluid. The performance parameters such as cooling capacity and coefficient of performance of the hybrid cycle is analyzed by varying the temperature of evaporator from −10 °C to 10 °C, absorber and condenser temperatures in first stage from 25 °C to 45 °C, degassing width in both the stages from 0.02 to 0.12 and is compared with the conventional triple effect absorption cycle. The results of the analysis show that the maximum cooling capacity attained in the hybrid cycle is 472.3 kW, at 10 °C evaporator temperature and first stage degassing width of 0.12. The coefficient of performance of the hybrid cycle is about 30 to 65% more than the coefficient of performance of conventional triple effect cycle.


2021 ◽  
Vol 9 (5) ◽  
pp. 1087
Author(s):  
Loreley Castelli ◽  
María Laura Genchi García ◽  
Anne Dalmon ◽  
Daniela Arredondo ◽  
Karina Antúnez ◽  
...  

RNA viruses play a significant role in the current high losses of pollinators. Although many studies have focused on the epidemiology of western honey bee (Apis mellifera) viruses at the colony level, the dynamics of virus infection within colonies remains poorly explored. In this study, the two main variants of the ubiquitous honey bee virus DWV as well as three major honey bee viruses (SBV, ABPV and BQCV) were analyzed from Varroa-destructor-parasitized pupae. More precisely, RT-qPCR was used to quantify and compare virus genome copies across honey bee pupae at the individual and subfamily levels (i.e., patrilines, sharing the same mother queen but with different drones as fathers). Additionally, virus genome copies were compared in cells parasitized by reproducing and non-reproducing mite foundresses to assess the role of this vector. Only DWV was detected in the samples, and the two variants of this virus significantly differed when comparing the sampling period, colonies and patrilines. Moreover, DWV-A and DWV-B exhibited different infection patterns, reflecting contrasting dynamics. Altogether, these results provide new insight into honey bee diseases and stress the need for more studies about the mechanisms of intra-colonial disease variation in social insects.


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