Megajoules Of Energy Research Articles

Energy in 2023

The new year 2023 arrives with promising developments in fusion research. In December, scientists at the US National Ignition Facility (NIF) focused 2.05 megajoules of laser light onto a capsule of fusion fuel and produced 3.15 megajoules of energy. This was the first laser-driven fusion demonstration in which the reaction produced more energy than the laser light used to start it-a goal set for NIF at its founding. Massachusetts Institute of Technology physicist Anne White, who was not involved in the work, described it to Science as "a major breakthrough." After a year of ups and downs in science policy and research, this was the kind of exciting event needed to propel scientists into the promises of 2023.

Burning plasma achieved in inertial fusion

Obtaining a burning plasma is a critical step towards self-sustaining fusion energy1. A burning plasma is one in which the fusion reactions themselves are the primary source of heating in the plasma, which is necessary to sustain and propagate the burn, enabling high energy gain. After decades of fusion research, here we achieve a burning-plasma state in the laboratory. These experiments were conducted at the US National Ignition Facility, a laser facility delivering up to 1.9 megajoules of energy in pulses with peak powers up to 500 terawatts. We use the lasers to generate X-rays in a radiation cavity to indirectly drive a fuel-containing capsule via the X-ray ablation pressure, which results in the implosion process compressing and heating the fuel via mechanical work. The burning-plasma state was created using a strategy to increase the spatial scale of the capsule2,3 through two different implosion concepts4–7. These experiments show fusion self-heating in excess of the mechanical work injected into the implosions, satisfying several burning-plasma metrics3,8. Additionally, we describe a subset of experiments that appear to have crossed the static self-heating boundary, where fusion heating surpasses the energy losses from radiation and conduction. These results provide an opportunity to study α-particle-dominated plasmas and burning-plasma physics in the laboratory.

How Profitable and Energy-Efficient Is Nepal’s Crop Production? A Case Study of Spring Rice Production in Jhapa District

We investigated the energy usage, economics, and global warming potential (GWP) of spring rice production via farm sizes in Nepal. Seventy farmers were selected via purposive sampling methods, and data were collected by interviewing the farmers on site. It was found that 22,987 mega joules of energy per hectare (MJ/ha) was invested in order to yield 77,355 MJ/ha worth of outputs (5262 kg/ha). The analysis shows that the highest share of energy input was contributed by machinery (33.50%) and least by chemicals (0.96%). It was further found that spring rice farming in Nepal is less energy productive (0.23 kg/MJ) and less energy efficient (3.37) than that of neighboring countries—such as India, China, and Pakistan. The total GWP is estimated about 720.56 kg CO2eq/ha. The average cost of production was found to equate to USD810.24/ha (or USD0.154/kg of production), and that profit only reached USD73.93/ha. This study found that energy use, cost of production, and yield per ha all generally decrease as the size of the landholding increases, whereas energy use efficiency and profits increase to an optimum level of land size and inputs. Low profits could be the result of the small size of landholdings and low levels of mechanization. This can be improved by increasing energy inputs and practicing community-farming.

Mitigation of GHG Emission by Replacing Diesel Buses with Electric Buses in Kathmandu Valley “A Case Study of Sajha Yatayat”

The net benefit of replacing diesel bus by electric bus in Kathmandu Valley is found positive. The net benefits of replacing diesel bus by electric bus is found to be NRs 8,31,776.So, per bus per year in the context of Sajha yatayat, the government should encourage the introduction of electric bus inside Kathmandu Valley. The four types of scenarios including one Business as usual scenario and other three different replacement scenarios, namely, ESB25, ESB50 and ESB100 for the period 2019-2035 are analyzed in this study. The 15.5, 31.2 and 62.4 Million Mega joule of energy can be saved in ESB25, ESB50 and ESB100 scenarios respectively in comparison to BAU scenario. The cumulative cost saved from avoided energy is 0.12, 0.25 and 0.5 million US dollars at constant price of 2019 under ESB25, ESB50 and ESB100 scenarios respectively in comparison to BAU scenario. The total GHG emissions avoided is 15.6, 31.2 and 62.41 thousand tons under ESB25, ESB50 and ESB100 scenarios respectively in comparison to BAU scenario. The cumulative revenue generated is 0.15, 0.31 and 0.62 million US dollars at constant price of 2019 under ESB25, ESB50 and ESB100 scenarios respectively in comparison to BAU scenario. Since net benefit of replacing both old and new diesel bus is positive, ESB100 scenario is the best option to replace diesel buses by electric uses.

The outsized trophic footprint of marine urbanization

Artificial structures are proliferating along coastlines worldwide, creating new habitat for heterotrophic filter feeders. The energy demand of this heterotrophic biomass is likely to be substantial, but is largely unquantified. Combining in situ surveys, laboratory assays, and information obtained from geographic information systems, we estimated the energy demands of sessile invertebrates found on marine artificial structures worldwide. At least 950,000 metric tons of heterotrophic biomass are associated with commercial ports around the world, emitting over 600 metric tons of carbon dioxide into the atmosphere and consuming 5 million megajoules of energy per day. We propose the concept of a trophic “footprint” of marine urbanization, in which every square meter of artificial structure can negate the primary production of up to 130 square meters of surrounding coastal waters; collectively, these structures not only act as energy sinks and carbon sources, but also potentially reduce the productivity of coastal food webs.

Harvesting Energy Wasted from Footsteps Using Piezoelectric Technology to Utilize in Low-Power Applications: A Conceptual Approach and Design

The Earth, as proved by extensive scientific research, is at a critical juncture. With our rising Carbon Footprint and depletion of resources, the long-term future of the planet is in danger of an energy crisis and massive environmental changes. One of the primary culprits for this predicament is the burning of non- renewable sources of energy, which are drying up and results in massive carbon emissions. As a result, the world has been turning to renewable sources for a solution. Some of the most popular solutions are hydro, solar and wind power. The need for humankind to step up in order to prevent the damage to and save the environment is becoming more prominent, every second, because, it is the only solution available. Every day, billions of people place billions of footprints everywhere in the world, at their homes, transportation hubs, shopping malls: the list goes on. One of the facts that has been neglected is that these footsteps are a waste of potentially billions of mega joules of energy. This paper will describe a conceptual approach and a design on how to convert this wasted kinetic energy into electrical energy, providing a source of inexpensive electricity that can be utilized in low-power applications in our daily lives, as a solution to the rising carbon footprint of the Earth.

Influence of Moisture Content, Particle Size, and Binder Ratio on Quality and Economics of Rice Straw Briquettes

Rice straw as solid residues are biomass residue materials that are not optimally used by farmers in Punjab and potentially become environmental pollutant. A large amount of rice straw (17 million tons) is generated and left as much in combine harvested rice fields in Punjab, India. It is very difficult to manage such huge amount of rice straw thus, farmers resort to burning it which leads to greenhouse gas emissions like CO2 due to open field burning and loss of rich organic matter present in the soil. Further due to imposition of restrictions by the state government, the practice of burning rice straw has now become an offense. So farmers are looking for alternatives which are economically viable. Rice straw can be effectively used as bio energy as it has about the same heating value (15 kJ kg−1) as that of wood, half that of good quality coal and one third of oil. The operational conditions required to produce high-quality chopped rice straw briquettes have not been determined and this study determined the optimal moisture content, particle size, and binder ratio required to produce rice straw briquettes. The optimized conditions resulted in formation of high-density (1030.38–1159.22 kg m−3) briquettes with durability ranging from 71.9 to 92.3% with minimum power requirement for briquetting (36.60 kW), maximum calorific value of 15.61 MJ kg−1, and minimum ash content (16.34%).Total cost of making chopped rice straw briquettes was 0.041 USD per kg and 0.00281 USD per mega joule of energy. Cost of briquetting from chopped rice straw with 10 and 20% cotton stalks was 0.050 and 0.051 USD per kg, respectively, and 0.0033 USD per mega joule of energy. Also, the briquettes prepared from chopped rice straw with and without cotton stalk as a binder were economically viable.

Tick front-of-pack label has a positive nutritional impact on foods sold in New Zealand.

Nutritional impact of the Tick front-of-pack labelling programme was evaluated by investigating nutrient changes to the purchased food supply and the nutritional quality of Tick v. non-Tick products. Factors influencing manufacturers' decisions to develop and license Tick products were also explored. Observational, cross-sectional and change over time data. New Zealand food supply, 2011-2013. Forty-five newly licensed Tick products from five food categories were analysed: Edible Oil Spreads, Yoghurt & Dairy Desserts, Frozen Desserts, Ready Meals and Processed Poultry. Four manufacturers of these products were interviewed. Eligible products (31 % of all Tick products in these categories) removed 4·1 million megajoules of energy, 156·0 tonnes of saturated fat, 15·4 tonnes of trans-fat and 4·0 tonnes of sodium from food products sold in New Zealand over three years. In each food category, these Tick products were, on average, 14-76 % lower in energy, saturated fat, trans-fat and sodium than non-Tick products, indicating healthier options. Participating manufacturers reported that international market trends and consumer demand for tasty, healthy foods primarily influenced Tick product development and sales. Tick was used as part of their marketing strategy as it was perceived as a credible, well-recognised logo for New Zealand consumers. Tick was cited as the primary initiative encouraging saturated fat reduction. The Tick Programme is continuing to encourage manufacturers to make meaningful improvements to the nutritional quality of the New Zealand food supply. Over time, these changes are likely to influence population nutrient intakes and reduce CVD risk factors.

Braking performance and influence of microstructure of advanced cast irons for heavy goods vehicle brake discs

It is well known that truck brakes dissipate several megajoules of energy every few seconds, which leads to high thermal stresses in the rubbing parts. Therefore, premature failure by cracking of truck brake discs is a matter of major concern. Improving the design and material of brake discs may enhance braking performance. This study focuses on the latter aspect and was carried out with the aim of developing new material solutions for increasing disc lifespan. To do so, braking experiments were conducted on a specially designed braking tribometer. The brake pads that were used were made from a commercial brake lining material. Two advanced cast irons with different graphite morphology were studied in comparison with the lamellar grey cast iron commonly used for brake disc. To verify the friction and thermal behaviour of the two cast irons, braking tests were carried out as a series of stop-brakings with increasing dissipated power and energy and as a series of slowdowns to achieve heat accumulation effects. Thermal phenomena were studied through bulk temperature measurements and infrared monitoring of the disc surface. Friction behaviour, braking performance and variations in thermal loading were analysed in relation to the level of energy dissipation. The two advanced cast irons and lamellar cast iron had equivalent braking performance and stored similar amounts of heat, according to their thermophysical properties. Observations of the rubbing surfaces indicated damage mechanisms affected by the graphite morphology. Less plastic deformation on the surface was observed with an interdendritic graphite.

Thermocracks®, a Specific Testing Machine for Evaluation of the Thermal Fatigue Resistance of Materials

Cracking by thermal fatigue is one of the major problems encountered during the operation of numerous parts such as exhaust manifolds or brake discs. One way to improve their lifespan is to develop new materials solutions. Estimating thermo-mechanical fatigue resistance of new materials can be performed with a specific test machine developed by CTIF, associating a multi-position wheel, an induction heating and a cooling by air blowing. Test consists in measuring the number of thermal cycles corresponding to the first crack appearance and to the complete failure of a specific versatile sample.Two examples of studies performed with this machine are shown hereafter.First tests were performed to compare the thermo-mechanical fatigue resistance of different grades of ferritic spheroidal graphite cast iron. These materials are an interesting alternative to alloyed steels or nickel-alloyed cast irons, for the constitution of exhaust manifolds and turbine housings working in the upper-middle temperatures (up to 950°C). The compared materials are SG irons alloyed with silicon (with or without molybdenum), and aluminium.Truck brakes dissipate several megajoules of energy every few seconds, which leads to high thermal stresses in the rubbing discs. Therefore, truck brake discs are mainly damaged by thermal fatigue cracking. One improvement way is to evolve disc material with the aim of increasing their thermal fatigue resistance while keeping the braking performance. For the thermal fatigue tests being as close as possible to real brake conditions, a specific geometry of sample and inductor was developed, to reproduce the thermal gradients observed during tests on real brake discs. The test parameters were then chosen after a coupled numerical-experimental study on full-scale braking. Behaviour of different materials under cycling loading (microstructural changes and cracking) is compared with regard to the results obtained during braking tests.

Computation of inductances for pulsed power generators using a semianalytic method

Pulsed power generators being developed for applications in electromagnetic launch operate at high speeds and are intended to deliver megajoules of energy within a few milliseconds. The self-inductances of the rotor and the stator, L/sub r/, L/sub s/, and the mutual inductance, M(/spl theta/), are required to model the performance of these machines. In general, three-dimensional (3-D) field computations are required for the calculation of inductances, and the integration of the stored energy has to be carried out over an infinite domain. The domain of integration could be reduced to just the volumes of current-carrying conductors, using equivalent expressions for the total energy involving the dot product of the current density and the magnetic vector potential. A semianalytic code, Faraday, has been developed using this method for the computation of L/sub r/, L/sub s/, and M(/spl theta/). The 3-D topology of conductors with rectangular cross sections in the rotor and the stator is described by a set of discrete rectangular segments (parallelepipeds) with specified current directions. The segments are continuous along the axis. Analytic integral expressions for the total energy of differential current-carrying segments are used to calculate the total energies and inductances. The inductances L/sub r/, L/sub s/, and M(/spl theta/) for a model pulsed disk alternator were computed using Faraday. The results compare favorably with experimental data.

Light-ion beams for inertial confinement fusion

Inertial confinement fusion requires the generation and focusing of several megajoules of energy at > 100 TW power and > 100 TW·cm−2 power density onto a target for approximately 10 ns. Lasers and particle beam drivers have been developed for this purpose. Lightion beams offer the potential for a cost-effective, efficient and versatile driver with excellent energy deposition and no significant preheat. The research and development to date has emphasized technology development of the driver. Advances in pulsed power technology, magnetically insulated power flow, intense ion beam generation, focusing and transport, and ion beam deposition have led to the Particle Beam Fusion Accelerator II at Sandia National Laboratories which will begin operation in January 1986. This accelerator has the potential for achieving ignition of thermonuclear fuel in the laboratory.

Repetitive Pulse Accelerator Technology for Light Ion Inertial Confinement Fusion

Successful ignition of an inertial confinement fusion (ICF) pellet is calculated to require that several megajoules of energy be deposited in the pellet's centimeter-sized shell within 10 ns. This implies a driver power of several hundreds of terawatts and power density around 100 TW/cm2 . The Sandia ICF approach is to deposit the energy with beams of 30 MV lithium ions. The first accelerator capable of producing these beams (PBFA II, 100 TW) will be used to study beam formation and target physics on a single pulse basis. To utilize this technology for power production, repetitive pulsing at rates that may be as high as 10 Hz will be required. This paper will overview the technologies being studied for a repetitively pulsed ICF accelerator. As presently conceived, power is supplied by rotating machinery providing 16 MJ in 1 ms. The generator output is transformed to 3 MV, then switched into a pulse compression system using laser triggered spark gaps. These must be synchronized to about 1 ns. Pulse compression is performed with saturable inductor switches, the output being 40 ns, 1.5 MV pulses. These are transformed to 30 MV in a self-magnetically insulated cavity adder structure. Space charge limited ion beams are drawn from anode plasmas with electron counter streaming being magnetically inhibited. The ions are ballistically focused into the entrances of guiding discharge channels for transport to the pellet. The status of component development from the prime power to the ion source will be reviewed.

Pulsed Power Generators

Pulsed power generators are capable of delivering as much as megajoules of energy in pulses of 100 nsec or less. A brief review of the technological approach to this problem is presented as well as the description of three different devices: Gamble II, AURORA, and a small laboratory device designed at NRL.

Rectifier Type Flux Pump

In this paper a detailed description is given of an integrated system of a Rectifier Type Flux Pump.Solving a most significant problem occured during a current exchange from one cryotron to the other, a maximum current of about 1, 300Amp is obtaind and produced a field strength of about 30kG in a small superconducting coil of L=1.7mH.Current charge, discharge and persistent mode operation is very easily performed by changing a phase shift of the control unit.There considered to be no basic problems in the small magnet systems with Flux Pump. But in applying Flux Pumps to magnet systems storing many megajoules of energy, several problems had to be solved which were not directly related to the Flux Pump itself. One and essencial of these is “Reliability” of the Systems.