scholarly journals Investigation of the Impact Factors on the Optimal Intermediate Temperature in a Dual Transcritical CO2 System with a Dedicated Transcritical CO2 Subcooler

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 309 ◽  
Author(s):  
Yulong Song ◽  
Haidan Wang ◽  
Feng Cao

As a natural fluid with superior environment advantages, CO2 is used to constitute a dual transcritical system to reduce performance deterioration under high gas-cooler outlet temperature. Aiming at the system configuration, improvement potential, and optimization, the proposed system is deeply analyzed, and corresponding coupling models are presented in detail. First, the veracity of simulation models is completely verified by comparing with previous measurements. Then, the existence of the optimal intermediate temperature is validated, while the optimal values are found to increase with the augmentation in ambient and water-feed temperatures. Moreover, the negative effects of the pinch point on the heat transfer inside the gas cooler could be greatly reduced by using the dual gas cooler. Finally, a predictive correlation for optimal intermediate temperature determination with ambient and water-feed temperature as independent variables is proposed, which provides a theoretical basis for the proposed system to realize efficient control in the industrialization process.

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 770
Author(s):  
Cong Wang ◽  
Barbara Amon ◽  
Karsten Schulz ◽  
Bano Mehdi

Nitrous oxide (N2O) is a long-lived greenhouse gas that contributes to global warming. Emissions of N2O mainly stem from agricultural soils. This review highlights the principal factors from peer-reviewed literature affecting N2O emissions from agricultural soils, by grouping the factors into three categories: environmental, management and measurement. Within these categories, each impact factor is explained in detail and its influence on N2O emissions from the soil is summarized. It is also shown how each impact factor influences other impact factors. Process-based simulation models used for estimating N2O emissions are reviewed regarding their ability to consider the impact factors in simulating N2O. The model strengths and weaknesses in simulating N2O emissions from managed soils are summarized. Finally, three selected process-based simulation models (Daily Century (DAYCENT), DeNitrification-DeComposition (DNDC), and Soil and Water Assessment Tool (SWAT)) are discussed that are widely used to simulate N2O emissions from cropping systems. Their ability to simulate N2O emissions is evaluated by describing the model components that are relevant to N2O processes and their representation in the model.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Nurettin Çetinkaya ◽  
Farhana Umer

The effects of the wind/PV grid-connected system (GCS) can be categorized as technical, environmental, and economic impacts. It has a vital impact for improving the voltage in the power systems; however, it has some negative effects such as interfacing and fault clearing. This paper discusses different grounding methods for fault protection of High-voltage (HV) power systems. Influences of these grounding methods for various fault characteristics on wind/PV GCSs are discussed. Simulation models are implemented in the Alternative Transient Program (ATP) version of the Electromagnetic Transient Program (EMTP). The models allow for different fault factors and grounding methods. Results are obtained to evaluate the impact of each grounding method on the 3-phase short-circuit fault (SCF), double-line-to-ground (DLG) fault, and single-line-to-ground (SLG) fault features. Solid, resistance, and Petersen coil grounding are compared for different faults on wind/PV GCSs. Transient overcurrent and overvoltage waveforms are used to describe the fault case. This paper is intended as a guide to engineers in selecting adequate grounding and ground fault protection schemes for HV, for evaluating existing wind/PV GCSs to minimize the damage of the system components from faults. This research presents the contribution of wind/PV generators and their comparison with the conventional system alone.


Author(s):  
Настя П. Савчук

The article seeks to provide a rationale for using a benchmarking toolkit to enhance the small and medium business efficiency along with exploring the primary types and the content of benchmarking. To assess the possibility of applying benchmarking instruments as to the enterprise business processes, the study offers a framework of indicators to manage the performance efficiency of small and medium-sized enterprises. A comparative assessment of the competitiveness of consumer goods manufacturing sectoral structure patterns in Turkey, China and the EU has been carried out. The following criteria to compare the alternatives were selected out of the most significant factors affecting business competitiveness in the given industry: 1) price of finished goods; 2) product quality; 3) payment convenience; 4) meeting customer demands; 5) brand awareness; 6) customer loyalty to a manufacturer. Ranking the factors hindering sustainable development of small and medium businesses allowed to identify the most significant ones, such as: competition resulted from shadow economy, low investment activity, barriers to finished goods sales, acute shortage of qualified personnel, insufficient focus to innovation, lack of effective marketing, lack of domestic equipment and raw materials. To eliminate the negative effects of the impact factors, a hierarchical model of coherent development strategies at different levels (national, regional and the enterprise level) has been suggested through the identification by means of benchmarking the reference samples (standards) for individual components of a consumer goods industry development plan or a set of individual projects. The implementation of this approach contributes to enhancing the investment process, boosting innovation and increasing the efficiency of resources utilization by small and medium businesses.


2012 ◽  
Vol 17 (3) ◽  
pp. 190-198 ◽  
Author(s):  
Günter Krampen ◽  
Thomas Huckert ◽  
Gabriel Schui

Exemplary for other than English-language psychology journals, the impact of recent Anglicization of five former German-language psychology journals on (1) authorship (nationality, i.e., native language, and number of authors, i.e., single or multiple authorships), (2) formal characteristics of the journal (number of articles per volume and length of articles), and (3) number of citations of the articles in other journal articles, the language of the citing publications, and the impact factors (IF) is analyzed. Scientometric data on these variables are gathered for all articles published in the four years before anglicizing and in the four years after anglicizing the same journal. Results reveal rather quick changes: Citations per year since original articles’ publication increase significantly, and the IF of the journals go up markedly. Frequencies of citing in German-language journals decrease, citing in English-language journals increase significantly after the Anglicization of former German-language psychology journals, and there is a general trend of increasing citations in other languages as well. Side effects of anglicizing former German-language psychology journals include the publication of shorter papers, their availability to a more international authorship, and a slight, but significant increase in multiple authorships.


Author(s):  
Jeeyun Oh ◽  
Mun-Young Chung ◽  
Sangyong Han

Despite of the popularity of interactive movie trailers, rigorous research on one of the most apparent features of these interfaces – the level of user control – has been scarce. This study explored the effects of user control on users’ immersion and enjoyment of the movie trailers, moderated by the content type. We conducted a 2 (high user control versus low user control) × 2 (drama film trailer versus documentary film trailer) mixed-design factorial experiment. The results showed that the level of user control over movie trailer interfaces decreased users’ immersion when the trailer had an element of traditional story structure, such as a drama film trailer. Participants in the high user control condition answered that they were less fascinated with, absorbed in, focused on, mentally involved with, and emotionally affected by the movie trailer than participants in the low user control condition only with the drama movie trailer. The negative effects of user control on the level of immersion for the drama trailer translated into users’ enjoyment. The impact of user control over interfaces on immersion and enjoyment varies depending on the nature of the media content, which suggests a possible trade-off between the level of user control and entertainment outcomes.


2020 ◽  
pp. 41-50
Author(s):  
Ph. S. Kartaev ◽  
I. D. Medvedev

The paper examines the impact of oil price shocks on inflation, as well as the impact of the choice of the monetary policy regime on the strength of this influence. We used dynamic models on panel data for the countries of the world for the period from 2000 to 2017. It is shown that mainly the impact of changes in oil prices on inflation is carried out through the channel of exchange rate. The paper demonstrates the influence of the transition to inflation targeting on the nature of the relationship between oil price shocks and inflation. This effect is asymmetrical: during periods of rising oil prices, inflation targeting reduces the effect of the transfer of oil prices, limiting negative effects of shock. During periods of decline in oil prices, this monetary policy regime, in contrast, contributes to a stronger transfer, helping to reduce inflation.


2019 ◽  
pp. 46-64 ◽  
Author(s):  
Vladimir V. Klimanov ◽  
Sofiya М. Kazakova ◽  
Anna A. Mikhaylova

The article examines the impact of various socio-economic and financial indicators on the resilience of Russian regions. For each region, the integral index of resilience is calculated, and its correlation dependence with the selected indicators is revealed. The study confirms the relationship between fiscal resilience and socio-economic resilience of the regions. The analysis of panel data for 75 regions from 2007 to 2016 shows that there are significant differences in the dynamics of indicators in different periods. In particular, the degree of exposure to the negative effects of the crises of 2008—2009 and 2014—2015 in non-resilient regions is higher than in resilient ones.


Author(s):  
Nham Phong Tuan ◽  
Nguyen Ngoc Quy ◽  
Nguyen Thi Thanh Huyen ◽  
Hong Tra My ◽  
Tran Nhu Phu

The objective of this study is to investigate the impact of seven factors causing academic stress on students of University of Economics and Business - Vietnam National University: Lack of leisure time, Academic performance, Fear of failure, Academic overload, Finances, Competition between students, Relationships with university faculty. Based on the results of a practical survey of 185 students who are attending any courses at the University of Economics and Business - Vietnam National University, the study assesses the impact of stress factors on students. The thesis focuses on clarifying the concept of "stress" and the stress level of students, while pointing out its negative effects on students. This study includes two cross-sectional questionnaire surveys. The first survey uses a set of 16 questions to assess students’ perceptions and attitudes based on an instrument to measure academic stress - Educational Stress Scale for Adolescents (ESSA). The second survey aims to test internal consistency, the robustness of the previously established 7-factor structure. Henceforth, the model was brought back and used qualitatively, combined with Cronbach’s Alpha measurement test and EFA discovery factor analysis. This study was conducted from October 2019 to December 2019. From these practical analyzes, several proposals were made for the society, the school and the students themselves.


2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Turkan Ahmet

The past few decades of ongoing war in Iraq has had a dramatic impact on the health of Iraq’s population. Wars are known to have negative effects on the social and physical environments of individuals, as well as limit their access to the available health care services. This paper explores the personal experiences of my family members, who were exposed to war, as well as includes information that has been reviewed form many academic sources. The data aided in providing recommendations and developing strategies, on both local and international levels, to improve the health status of the populations exposed to war.


2020 ◽  
Vol 10 (5) ◽  
pp. 578-586
Author(s):  
Areeg M. Abdelrazek ◽  
Shimaa A. Haredy

Background: Busulfan (Bu) is an anticancer drug with a variety of adverse effects for cancer patients. Oxidative stress has been considered as a common pathological mechanism and it has a key role in the initiation and progression of liver injury by Bu. Aim: The study aimed to evaluate the antioxidant impact of L-Carnitine and Coenzyme Q10 and their protective role against oxidative stress damage in liver tissues. Methods and Material: Thirty-six albino rats were divided equally into six groups. G1 (con), received I.P. injection of DMSO plus 1 ml of distilled water daily by oral gavages; G2 (Bu), received I.P. injection of Bu plus 1 ml of the distilled water daily; G3 (L-Car), received 1 ml of L-Car orally; G4 (Bu + L-Car) received I.P. injection of Bu plus 1 ml of L-Car, G5 (CoQ10) 1 ml of CoQ10 daily; and G6 (Bu + CoQ10) received I.P. injection of Bu plus 1 ml of CoQ10 daily. Results: The recent data showed that Bu induced significant (P<0.05) elevation in serum ALT, AST, liver GSSG, NO, MDA and 8-OHDG, while showing significant (P<0.05) decrease in liver GSH and ATP. On the other hand, L-Carnitine and Coenzyme Q10 ameliorated the negative effects prompted by Bu. Immunohistochemical expression of caspase-3 in liver tissues reported pathological alterations in Bu group while also showed significant recovery in L-Car more than CoQ10. Conclusion: L-Car, as well as CoQ10, can enhance the hepatotoxic effects of Bu by promoting energy production in oxidative phosphorylation process and by scavenging the free radicals.


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