Energy breakeven in thermonuclear fusion. An advanced concept for efficient energy input with positive implications for energy saving and the geoscience of climate change

2021 ◽  
Vol 34 (4) ◽  
pp. 596-604
Author(s):  
Michel de Peretti ◽  
Arne P. Olson ◽  
Emilio Panarella
Keyword(s):  
Energy Input ◽  
Fusion Energy ◽  
Thermodynamic Cycle ◽  
Economic Benefits ◽  
Thermonuclear Fusion ◽  
Thermodynamic Efficiency ◽  
The Novel ◽  
Heat Engines ◽  
Wide Scale ◽  
Opposite View

The motivation of the present study is energy generation with thermonuclear fusion. Specifically, it is the attainment of breakeven conditions with a fusionable plasma whereby the output fusion energy is at least equal to the energy expended in creating the plasma and bringing it to fusionable conditions. This objective has eluded the physics community for the past seven decades. It is here suggested that perhaps the reason is that ever-bigger fusion machines are built, which unfortunately have brought results not in line with the expectations, in terms of desired fusion output. The opposite view is taken here, where attention is paid to the energy input, with the objective of minimizing the energy losses. One of the most important losses is a consequence of the limited thermodynamic efficiency of conventional engines that convert heat to work, thus generating the electricity involved in the energy input. This preliminary study shows that the efficiency can be improved if a novel thermodynamic cycle is used with heat recovery and recirculation. No attention is paid in the present study to the applicability of the novel cycle to a working engine but only to its feasibility. After the delineation of the concept, we use a simulation program to confirm that such approach is promising, and the objective of improving the thermodynamic efficiency of conventional heat-engines by at least 10% is realistic. Finally, the economic benefits are quantified of such substantial efficiency improvement on a world-wide scale. Mitigation of the damage to our environment due to the reduced heat rejection is also quantified.

scholarly journals Learning the best nanoscale heat engines through evolving network topology

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuto Ashida ◽  
Takahiro Sagawa
Keyword(s):  
Network Topology ◽  
Heat Engine ◽  
Search Space ◽  
Single Electron ◽  
Thermodynamic Efficiency ◽  
Full Potential ◽  
Thermal Systems ◽  
Nanoscale Systems ◽  
Heat Engines ◽  
Many Body Interactions

AbstractThe quest to identify the best heat engine has been at the center of science and technology. Considerable studies have so far revealed the potentials of nanoscale thermal machines to yield an enhanced thermodynamic efficiency in noninteracting regimes. However, the full benefit of many-body interactions is yet to be investigated; identifying the optimal interaction is a hard problem due to combinatorial explosion of the search space, which makes brute-force searches infeasible. We tackle this problem with developing a framework for reinforcement learning of network topology in interacting thermal systems. We find that the maximum possible values of the figure of merit and the power factor can be significantly enhanced by electron-electron interactions under nondegenerate single-electron levels with which, in the absence of interactions, the thermoelectric performance is quite low in general. This allows for an alternative strategy to design the best heat engines by optimizing interactions instead of single-electron levels. The versatility of the developed framework allows one to identify full potential of a broad range of nanoscale systems in terms of multiple objectives.

Jane Austen’s Questioning of Gender and Genres

2019 ◽  
Author(s):  
Marie-Laure MASSEI-CHAMAYOU
Keyword(s):  
Eighteenth Century ◽  
Social Order ◽  
Power Relations ◽  
Jane Austen ◽  
The Political ◽  
The Novel ◽  
Conduct Books ◽  
Northanger Abbey ◽  
Gothic Novels ◽  
Opposite View

If Jane Austen admits in her correspondence that she was eventually pleased with Thomas Gisborne’s Enquiry into the Duties of the Female Sex (1797), the Anglican theologian nonetheless endorsed the prejudices shared by most eighteenth-century moralists towards novels. Now, in Northanger Abbey, a novel filled with literary allusions, Jane Austen’s narrator bravely takes the opposite view by launching into a bold defence of the genre. Besides resorting to a biting irony to scrutinize her society’s axioms, rules and power relations, her novels notably question Manichean representations of masculine and feminine roles. Jane Austen’s choice to distance herself from the strictly gendered models inherited from conduct books, sentimental, or gothic novels, further combines with her questioning of generic conventions. This article thus aims at exploring how Jane Austen engaged with these representations while articulating her subtle didacticism. Her aim was not merely to raise the respectability of the novel genre, but also to provide a possible answer to the crisis of values that was threatening the very foundations of the political and social order.

2025 Nuclear Code: The Vision for the Future of ASME Nuclear Codes and Standards

2018 ◽  
Author(s):  
Dale E. Matthews ◽  
Ralph S. Hill ◽  
Charles W. Bruny
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
New Technologies ◽  
Fusion Energy ◽  
Life Cycle Management ◽  
Economic Benefits ◽  
Plant Design ◽  
Element Analysis ◽  
Energy Devices ◽  
The Future

ASME Nuclear Codes and Standards are used worldwide in the construction, inspection, and repair of commercial nuclear power plants. As the industry looks to the future of nuclear power and some of the new plant designs under development, there will be some significant departures from the current light water reactor (LWR) technology. Some examples are gas-cooled and liquid metal-cooled high temperature reactors (HTRs), small modular reactors (SMRs), and fusion energy devices that are currently under development. Many of these designs will have different safety challenges from the current LWR fleet. Variations of the current LWR technology are also expected to remain in use for the foreseeable future. Worldwide, many LWRs are planned or are already under construction. However, technology for construction of these plants has advanced considerably since most of the current construction codes were written. As a result, many modern design and fabrication methods available today, which provide both safety and economic benefits, cannot be fully utilized since they are not addressed by Code rules. For ASME Nuclear Codes and Standards to maintain and enhance their position as the worldwide leader in the nuclear power industry, they will need to be modernized to address these items. Accordingly, the ASME Nuclear Codes and Standards organizations have initiated the “2025 Nuclear Code” initiative. The purpose of this initiative is to modernize all aspects of ASME’s Nuclear Codes and Standards to adopt new technologies in plant design, construction, and life cycle management. Examples include modernized finite element analysis and fatigue rules, and incorporation of probabilistic and risk-informed methodology. This paper will present the vision for the 2025 ASME Nuclear Codes and Standards and will discuss some of the key elements that are being considered.

Thermo-Mechanical Modeling of a Shape Memory Alloy Heat Engine

2011 ◽  
Author(s):  
Christopher B. Churchill ◽  
John Shaw
Keyword(s):  
Heat Transfer ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Heat Engine ◽  
The United States ◽  
Thermodynamic Efficiency ◽  
Low Grade ◽  
Heat Engines ◽  
Deformation Mechanics ◽  
Sma Spring

Two thirds of the energy generated in the United States is currently lost as waste heat, representing a potentially vast source of green energy. Low Carnot efficiency is an inherent limitation of extracting energy from low-grade thermal sources (temperature gradients near or below 100C), and SMA heat engines could be useful for those applications where low weight and packaging are overriding considerations. Although many shape memory alloy (SMA) heat engines have been proposed to harvest this energy, and a few have been built and demonstrated in past decades, they have not been commercially successful. Some of the barriers to commercialization include their perceived low thermodynamic efficiency, high material cost, low material durability, complexities when using fluid baths, and the lack of robust constitutive models and design tools. Recent advances, however, in SMA longevity, reductions in materials costs (as production volumes have increased), and a better understanding of SMA behavior have stimulated new research on SMA heat engines. The Lightweight Thermal Energy Recovery System (LighTERS) is an ongoing ARPA-E funded collaboration between General Motors, HRL Laboratories, Dynalloy, Inc., and the University of Michigan. In the LighTERS engine (a refinement of the Dr. Johnson engine), a closed loop SMA spring element generates mechanical power by pulling itself between alternating hot and cold air regions. The first known thermo-mechanical model for this type of heat engine was developed in three stages. First, the constitutive and heat transfer relationships of an SMA spring form were characterized experimentally. Second, those relationships were used as inputs in a steady-state model of the heat engine, including both convective heat transfer and large-deformation mechanics. Finally, the model was validated successfully against measurements of a experimental heat engine built at HRL Labs.

Fundamental Differences Between Conventional and Geared Turbofans

2009 ◽  
Author(s):  
Joachim Kurzke
Keyword(s):  
Fuel Consumption ◽  
Real Option ◽  
Pressure Ratio ◽  
Thermodynamic Cycle ◽  
Specific Fuel Consumption ◽  
Thermodynamic Efficiency ◽  
Aircraft Engines ◽  
Direct Drive ◽  
Significant Difference ◽  
Bypass Ratio

The potential for improving the thermodynamic efficiency of aircraft engines is limited because the aerodynamic quality of the turbomachines has already achieved a very high level. While in the past increasing burner exit temperature did contribute to better cycle efficiency, this is no longer the case with today’s temperatures in the range of 1900...2000K. Increasing the cycle pressure ratio above 40 will yield only a small fuel consumption benefit. Therefore the only way to improve the fuel efficiency of aircraft engines significantly is to increase bypass ratio — which yields higher propulsive efficiency. A purely thermodynamic cycle study shows that specific fuel consumption decreases continuously with increasing bypass ratio. However, thermodynamics alone is a too simplistic view of the problem. A conventional direct drive turbofan of bypass ratio 6 looks very different to an engine with bypass ratio 10. Increasing bypass ratio above 10 makes it attractive to design an engine with a gearbox to separate the fan speed from the other low pressure components. Different rules apply for optimizing turbofans of conventional designs and those with a gearbox. This paper describes various criteria to be considered for optimizing the respective engines and their components. For illustrating the main differences between conventional and geared turbofans it is assumed that an existing core of medium pressure ratio with a two stage high pressure turbine is to be used. The design of the engines is done for takeoff rating because this is the mechanically most challenging condition. For each engine the flow annulus is examined and stress calculations for the disks are performed. The result of the integrated aero-thermodynamic and mechanical study allows a comparison of the fundamental differences between conventional and geared turbofans. At the same bypass ratio there will be no significant difference in specific fuel consumption between the alternative designs. The main difference is in the parts count which is much lower for the geared turbofan than for the conventional engine. However, these parts will be mechanically much more challenging than those of a conventional turbofan. If the bypass ratio is increased significantly above 10, then the geared turbofan becomes more and more attractive and the conventional turbofan design is no longer a real option. The maximum practical bypass ratio for ducted fans depends on the nacelle drag and how the installation problems can be solved.

scholarly journals A. F. Pisemsky and Joint-Stock Companies in the Middle of 19th Century: Economic Processes and Literary Commentary (On the Basis of the Novel The Turbulent Sea)

2021 ◽  
Vol 20 (2) ◽  
pp. 110-119
Author(s):  
Anastasia A. Ponomareva
Keyword(s):  
Detailed Analysis ◽  
19Th Century ◽  
Coal Mine ◽  
Practical Knowledge ◽  
Russian Society ◽  
The Novel ◽  
Saint Petersburg ◽  
Economic Process ◽  
Wide Scale ◽  
Post War

In the following article, we analyze the trends in literary depiction of an important economic process in the post-war times (late 1850s), namely joint-stock companies, in A. F. Pisemsky’s novel The Turbulent Sea (1863). We detect and offer commentary on the parallels between descriptions of the ‘joint-stock fever’ depicted in the novel, and the materials on private enterpreneurship published in late 1850s. We offer a detailed analysis on the references to polemics between members of the Russian Society of Steamship Companies and Trade, one of the most influential joint-stock companies of the time, and N. P. Perosio, a journalist and economist, as well as the creator of The Reading Library and The Saint-Petersburg Bulletin. Our research is based on N. P. Perosio’s works, namely Notes on the Report by the Russian Society of Steamship Companies and Trade, The Protest, as well as Tondi’s The Reply to Sir Perosio’s Notes on the Report by the Russian Society of Steamship Companies and Trade, and V. Shultz’s A Dispute Between Sirs Perosio and Smirnov, The Response of Administrator Director of the Russian Society of Steamship Companies and Trade N. A. Novoselsky to Articles Criticizing Company Management, Notes and Projects of Establishment of a Coal Mine on Don, etc. We conclude that the analysis of strategies of depiction of economic processes in the novel offers a clearer understanding of A. F. Pisemsky’s perception of the ‘era of great reforms’. The novel shows that the idea expressed by the new government (development of private enterpreneurship) resulted in the emergence of unskilled enactors: the joint-stock companies were joined by people who lacked practical knowledge and did not wish to learn it, which, in its turn, resulted in wide-scale frauds performed by directors.

scholarly journals The Effectiveness of cloud-based telepathology system in China：Large-Sample Observational Study (Preprint)

2020 ◽  
Author(s):  
Xianying He ◽  
Linlin Wang ◽  
Li Wang ◽  
Jinghong Gao ◽  
Fangfang Cui ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Final Diagnosis ◽  
Turnaround Time ◽  
Economic Benefits ◽  
The Novel ◽  
Benign Lesions ◽  
Glass Slides ◽  
System P ◽  
Malignant Lesions ◽  
Telepathology System

BACKGROUND Telepathology is a potent strategy to overcome the shortage of senior pathologists, whole slid imaging (WSI) is the most advanced means and has been widely used in telepathology owning to its complete scanning of glass slides, but WSI occupies large storage space and computing resource, and the WSI retrieval is time-consuming. To compensate for these shortcomings of WSI, we have established a cloud-based telepathology system and conducted detailed evaluation of its implementation effects. OBJECTIVE The cloud-based telepathology system in China has been running for more than four years, and a large number of cases were submitted. The main purpose of this study is to evaluate the operation effect of this system based on a large sample, including the overview of the submitted cases, timeliness of telepathology reports, diagnostic accuracy, and economic benefits. METHODS A total of 23,167 cases submitted to the cloud-based telepathology system of the National Telemedicine Center of China from January 2016 to December 2019 were collected as subjects. The variation tendency of the report-timeliness from the system were analyzed for years. 564 patients who also directly visited the First Affiliated Hospital of Zhengzhou University and obtained final diagnoses were followed up to analyze the diagnostic accuracy of the system. RESULTS The amounts of participated hospitals and submitted cases rose year by year. Most samples were captured from uterus, gastrointestinal tract, bone or soft tissue, breast, and esophagus. 17,495 cases were confirmed, including 12,088 benign lesions, 5217 malignant lesions, and 190 borderline lesions, the proportion of malignant lesions in esophagus, lung/mediastinum, urinary and thoracic cavity/pleura was higher than that in benign lesions, which was different from other 22 anatomic sites. The median turnaround time was 16.93 hours and shortened yearly (between 2018 and 2019 adjusted P= .012, other groups adjusted P＜ .001), 82.88% cases were diagnosed in 48 hours. The telepathological diagnosis of 11 cases were discrepant with the final diagnosis, and the diagnostic accuracy of the system was 98.05%, with no statistical difference from the final diagnosis in hospital(P= .549). 300,000 dollars were saved for patients every year with this system. CONCLUSIONS The novel cloud-based telepathology system has the potential to relieve the shortage of pathologists in primary hospitals and simultaneously reduced the high medical costs for patients in China. It should be therefore promoted further to enhance the efficiency, quantity and quality of telepathological diagnoses.

A Thermo-Mechanical Model for SMA-Based Crank Heat Engines

2013 ◽  
Author(s):  
Franco Furgiuele ◽  
Carmine Maletta ◽  
Fabrizio Niccoli ◽  
Emanuele Sgambitterra
Keyword(s):  
Mechanical Model ◽  
Mechanical Response ◽  
Mechanical Energy ◽  
Heat Engine ◽  
Specific Power ◽  
Thermodynamic Efficiency ◽  
Physical Parameters ◽  
Low Grade ◽  
Heat Engines ◽  
Functional Features

Shape memory alloys (SMA) provide unique functional features and several SMA-based heat engines have been proposed in recent years, exploiting the thermally induced recovery capabilities of such class of materials. These engines represent simple and environmentally-friendly solutions to obtain mechanical energy from low-grade energy sources, such as warm wastewater, geothermal and solar sources. However, despite the scientific interest in last years, no commercial devices have been developed. One of the reasons of these unsuccessful commercial development is the lack of robust design tools. In the proposed work a thermo-mechanical model has been developed, which describes the mechanical response of a SMA-based crank heat engine, as a function of several geometrical configurations, such as the dimension and total number of cranks, as well as for different thermo-physical properties of the heating and cooling thermal sources. In particular, the engine is made of two parallel crankshafts and uses nickel-titanium helical springs operating between warm water and cold air. The model has been developed within the MatLab® Simulink software platform, and several simulations have been carried out to analyze the mechanical response of the engine, in terms of output characteristics (torque, specific power, thermodynamic efficiency) as a function of the aforementioned geometrical and physical parameters.

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