Neutral Energy Research Articles

Efficient black liquor conversion to power and H2 by adopting negative emission technology

Abstract Currently, some projects are underway to achieve high efficient conversion and reduce costs associated with H2 production. Biomass gasification is considered as a mature technology involving heat, steam, and oxygen to convert biomass to syngas including H2. Since biomass is treated as carbon neutral energy source, it can significantly reduce environmental impact. By integrating biomass conversion technology and carbon removal from environment, negative carbon emission can also be realized. In this study, co-production of H2 and power from black liquor (BL) is proposed based on enhanced process integration consisting of process integration and exergy recovery. The proposed system mainly consists of BL evaporation, gasification, syngas chemical looping (SCL), and power generation. The evaporation process employs exergy recovery using steam tube rotary evaporator. The effect of target moisture content on the evaporator performance is evaluated. Furthermore, the thermodynamics analysis of gasification is performed in circulating fluidized bed reactor based on Gibbs energy minimization. The SCL process comprises reducer, oxidizer and combustor and integrates with power generation. In addition, the concentrated CO2 can be generated during the SCL process, avoiding additional cost for separation.

Tensiomyography detects early hallmarks of bed-rest-induced atrophy before changes in muscle architecture.

In young and older people, skeletal muscle mass is reduced after as little as 7 days of disuse. The declines in muscle mass after such short periods are of high clinical relevance, particularly in older people who show a higher atrophy rate and a slower or even a complete lack of muscle mass recovery after disuse. Ten men (24.3 yr; SD 2.6) underwent 35 days of 6° head-down tilt bed rest, followed by 30 days of recovery. During bed rest, a neutral energy balance was maintained, with three weekly passive physiotherapy sessions to minimize muscle soreness and joint stiffness. All measurements were performed in a hospital at days 1-10, 16, 28, and 35 of bed rest (BR1-BR10, BR16, BR28, and BR35, respectively) and days 1, 3, and 30 after reambulation (R + 1, R + 3, and R + 30, respectively). Vastus medialis obliquus (VMO), vastus medialis longus (VML), and biceps femoris (BF) thickness (d) and pennation angle (Θ) were assessed by ultrasonography, whereas twitch muscle belly displacement (Dm) and contraction time (Tc) were assessed with tensiomyography (TMG). After bed rest, d and Θ decreased by 13-17% in all muscles ( P < 0.001) and had recovered at R + 30. Dm was increased by 42.3-84.4% ( P < 0.001) at BR35 and preceded the decrease in d by 7, 5, and 3 days in VMO, VML, and BF, respectively. Tc increased only in BF (32.1%; P < 0.001) and was not recovered at R + 30. TMG can detect early bed-rest-induced changes in muscle with higher sensitivity before overt architectural changes, and atrophy can be detected. NEW & NOTEWORTHY Detection of early atrophic processes and irreversible adaptation to disuse are of high clinical relevance. With the use of tensiomyography (TMG), we detected early atrophic processes before overt architectural changes, and atrophy can be detected using imaging technique. Furthermore, TMG detected irreversible changes of biceps femoris contraction time.

Discrete Alfv&eacute;n eigenmodes in HL-2A tokamak

Basing on HL-2A tokamak, applying a magnetohydrodynamic (MHD) simulate codes, we study the characteristics of discrete Alfven eigenmodes ( α TAEs, α is a measure of plasma pressure gradient) in the power deposition region of lower hybrid wave auxiliary heating scheme. We explore the distribution of α TAE upon varied different plasma profiles. Employing gyrokinetic-MHD hybrid simulate codes, we investigate α TAE kinetically excited by energetic particles produced by neutral beam injection. Furthermore, we study physical characteristics of α TAE destabilized by energy particles in the lower hybrid wave power deposition region. In addition, we find that there exist α TAEs in HL-2A tokamak with relatively small α values. Besides, the α TAEs are mainly distributed in the reversal magnetic shear region. There are the abundant α TAEs in the lower hybrid wave power deposition region, where the amount of lower hybrid wave power deposition is greater. Moreover, with different plasma profiles, abundant α TAEs are found in the different region in the directions of the small radius of the HL-2A tokamak. With the increase of the neutral beam injection energy, the multiple branches of α TAEs are developed kinetically into unstable modes, which may potentially affect the plasma confinement of tokamak.

Effects of a low-carbohydrate diet on performance and body composition in trained cyclists.

Previous evidence suggests that low-carbohydrate diets may improve body composition and performance relative to body weight in endurance athletes. This has been the first study that has attempted to evaluate the utility of low-carbohydrate diets in a sample of eleven trained and experienced road cyclists who consumed 10% of their caloric intake in the form of carbohydrates during four weeks while maintaining a neutral energy balance (50 kcal/kg/day). Body composition was evaluated through an electrical impedance assessment before and after the intervention while maximal power output (5 and 20 min) was measured on a bike trainer by following a standardized protocol and in the same room conditions for all the participants. The study was performed during the preseason, when the subjects could abstain from performing high-intensity workouts. The participants, eleven men aged 31 ± 5 years, performed four weekly 150 min training sessions at submaximal intensities and received nutritional support from a certified sport nutritionist. The intervention resulted in reduced total weight (-2.51 kg) and body fat percentage (2.42%), and improved relative power (+0.2 w/kg for 20 min and +0.25 w/kg for 5 min) values while absolute power remained unchanged. The results suggest that low-carbohydrate diets could be used in order to induce changes in body composition and improve relative power during the preseason. However, future research with larger sample sizes and a control group is needed in order to validate the results.

Production and Evaluation of Biogas from Mixed Fruits and Vegetable Wastes Collected from Arba Minch Market

The world is in need of a green, efficient, carbon- neutral energy source to replace fossil fuels. The search for energy alternatives involving locally available and renewable resource is one of the main concerns of governments, scientists, and business people worldwide. Biogas, formed by anaerobic digestion of organic materials makes sustainable, reliable and renewable energy possible. This study involves the construction of a lab scale biogas production plant digester. The production of biogas was carried out by employing the mixed substrates of 13 different fruit and vegetable wastes collected from Arbaminch vegetable market. The materials used as feed were Apple, Mango, Cabbage, Avocado, onion, potato, Tomato, Banana, Lemon, Orange, Carrot, Papaya and cow manure. The total solid, volatile solids, moisture content and ash content of the wastes were examined. The anaerobic digestion of fruit and vegetable wastes mixed with different waste took 35-40 days to produce biogas (for complete digestion). Anaerobic digestion is very sensitive to change in pH and it is important to maintain pH of 6.7-7.4 for healthy system. The process resulted in the production of nutrient rich slurry high C/N ratio. The presented data on the moisture content, total solid, volatile solid and ash content of the wastes shows that tomato had maximum moisture content of 95.02% and lemon had the least with a moisture content of 73.4%. The maximum TS were recorded in Avocado (24.47%). The VS in all wastes used for the study varied from 20% (carrot) to 46.5% (Mango) wastes. The characteristics of these wastes were found to be: TS 14.13% of wet weight, VS 26.71%, TS/VS initial 0.461 and TS/VS final 0.394 which lead to TS/VS lost 0.394. The carbon and nitrogen composition of these mixed wastes was 53.85% and 2.205% respectively. The cumulative biogas production was 105.5 mL/1000g of food waste. This was the most effective as it showed maximum percentage removal of organic matter due to efficient working of the digester. Therefore, the application of biogas technology has economic, environmental, health and social benefits. It ultimately contributes towards sustainable development.

Hydrogen Exhaling Metal-H &lt;sub&gt;2&lt;/sub&gt;O Battery

Sustainable production and utilization of hydrogen or “hydrogen economy” offers a carbon neutral energy pathway for stabilizing global mean temperatures. However, molecular hydrogen production by state-of-the-art steam reforming is prohibitively expensive, often requiring high temperatures ≥ 200 degree celsius and high pressures ≥ 25 bar, eventually mitigating its environmental advantages. This steam reforming pathway is well-known to carbonize the hydrogen fuel stream beyond the tolerance levels to be directly utilized in a fuel cell, consequently; energy intensive purification modules are often inevitable. Here we show an unusual battery chemistry which can exhale pure molecular hydrogen during electricity generation with the net cell reaction being the oxidation of the metal anode and the reduction of H2O to H2 fuel at the electrocatalytic cathode. It comprises a non-noble metal anode, an aqueous electrolyte and a cathode that is active towards electrocatalytic H2 evolution. During the discharge, the fuel exhaling battery delivered a power density of ~75 mW/cm2 while evolving ~3730 μmoles/hour of H2 fuel. Coupling of battery and water electrolyzer in a single device offers an unprecedented pathway for realizing “hydrogen economy” as electric power is harnessed during hydrogen fuel generation as well as its utilization.

Долгоживущие центры фотокатализа, создаваемые в ZnO резонансным возбуждением экситона

Along with TiO_2, ZnO is the main photocatalyst for a wide class of redox reactions used to convert light energy into chemical and for environmental cleanup. It has been shown that the creation in ZnO of surface intrinsic defects in ZnO i.e. vacancies in the anionic and cationic sublattices (F-type and V-type centers) - makes it possible to create long-lived (up to 10^3 s) photocatalysis centers and thus fundamentally (tens of times) to increase the quantum yield of reactions. Slow surface states — photocatalysis centers — are created by the diffusion of electrons and holes generated during interband transitions in the volume of the photoactivated sample. However, the transfer efficiency is sharply reduced due to carrier recombination and losses when overcoming the Schottky surface barrier. In this work, In order to reduce these losses during energy transfer to the surface, we used in this work neutral energy carriers — excitons. The high (60 meV) exciton binding energy in ZnO allows it to move at room temperature without decay. The radiation loss of the exciton energy in our experiments is effectively reduced by the formation of a surface 2D structure. The results obtained confirm the high efficiency of the exciton channel for the formation of surface long-lived F and V centers of photocatalysis in the processes of oxygen photoadsorption and photodesorption, imitating the full cycle of the redox photocatalytic reaction.

Effect of the cascade neutralization energy on the surface modification by the impact of slow highly charged ions

We consider the neutralization dynamics of slow highly charged ions in the interaction with a metal surface covered with a thin dielectric film from the standpoint of the surface modification. The quasi-resonant two-state vector model and the micro staircase model are used for the calculation of cascade neutralization energy for the ArZ+, KrZ+ and XeZ+ ions. The population of several ionic Rydberg states at each step of the neutralization cascade is demonstrated. The correlation between the neutralization and the potential energy is presented for moderate and very low ionic velocities and the relevance of this relation for the surface nanostructure formation is briefly discussed for a different angle of incidence and different dielectric materials.

Discursive practices around the body of the female athlete: An analysis of sport psychology interactions in elite sport

ObjectiveTo examine the discursive practices surrounding athletes’ bodies with a particular focus on a) how food, the body and agency around eating and exercising practices are constructed, as well as b) how dominant discourses and narratives are deployed. MethodA case study design was used, examining interactions from three female athletes with a sport psychologist regarding their body composition. The psychology sessions took place within an elite sport setting. Recordings from three initial psychology sessions were recorded. Analysis drew on a synthesis of discursive psychology and conversation analysis. ResultsCompeting depictions of food and the body were drawn on by the athletes and the psychologist in order to either reproduce or resist taken for granted notions about a need to reduce body composition to improve performance. Discursive tensions were evident in talk around female athletes’ bodies, with a performance narrative functioning to regulate athletes’ bodies, at the same time that athletes oriented to a dominant notion of the thin female body. Food was also variously constructed in moral terms and as a neutral energy source. Throughout the sessions, individual agency for the body and for resolving the ‘problem’ of body composition was reproduced, with broader discursive and institutional practices overlooked. ConclusionThis study provides an in insight into how talk around the body and eating practices takes place within one institutional context occurring within an elite sport setting. In particular, this study highlights how potentially problematic discourses and practices are privileged and reproduced or resisted. Shifting the focus to technique rather than body modification and nutrition may be beneficial for athletes’ wellbeing. Further implications for practice are discussed.

Determination of Chemical, Nutritional and Fermentation Properties of Citrus Pulp Silages

This study was carried out to investigate the possibilities of making silage from fruit juice industry waste.For this purpose, orange, lemon and tangerine pulp silage quality have been determined by comparing silage with maize and beet pulp silage.Treatment groups; 1) orange, 2) tangerine, 3) lemon, 4) maize and 5) sugar beet pulp. The silages were evaluated after 2 months from ensiling in the following areas: subjective evaluation, pH, dry matter, organic matter, crude protein, acid detergent fiber, neutral detergent fiber, ether extract and energy values (metabolizable energy) and net energy for lactation were calculated. As a result, it was determined that fruit juice industry residues were lower in terms of dry matter, but they contained higher energy due to their high organic matter content, digestibility and low cellulose content. In addition, it was determined that citrus pulp was evaluated as silage without any contribution.

Impact of CO2 prices on the design of a highly decarbonised coupled electricity and heating system in Europe

Ambitious targets for renewable energy and CO2 taxation both represent political instruments for decarbonisation of the energy system. We model a high number of coupled electricity and heating systems, where the primary sources of CO2 neutral energy are from variable renewable energy sources (VRES), i.e., wind and solar generators. The model includes hourly dispatch of all technologies for a full year for every country in Europe. In each model run, the amount of renewable energy and the level of CO2 tax are fixed exogenously, while the cost-optimal composition of energy generation, conversion, transmission and storage technologies and the corresponding CO2 emissions are calculated. We show that even for high penetrations of VRES, a significant CO2 tax of more than 100 €/tCO2 is required to limit the combined CO2 emissions from the sectors to less than 5% of 1990 levels, because curtailment of VRES, combustion of fossil fuels and inefficient conversion technologies are economically favoured despite the presence of abundant VRES. A sufficiently high CO2 tax results in the more efficient use of VRES by means of heat pumps and hot water storage, in particular. We conclude that a renewable energy target on its own is not sufficient; in addition, a CO2 tax is required to decarbonise the electricity and heating sectors and incentivise the least cost combination of flexible and efficient energy conversion and storage.

Neutral atoms and ion energies, accurate ionization potential, and electron affinities by polynomial generator coordinate Hartree–Fock method

We have developed accurate Gaussian basis functions obtained with the polynomial generator coordinate Hartree-Fock (p-GCHF) method for H, Zn, and Ga-Kr atoms. These basis sets have been applied in the calculation of nonrelativistic energies for neutral atoms, monovalent cations, monovalent anions, ionization potential (IP), and electron affinity (EA), with the objective of proving the quality of the basis set generated by the p-GCHF method. The total energies calculated for neutral atoms and monovalent cations and respective IP were minimally affected by the addition of polarization functions and their precision was comparable to the values reported in the literature. The relative errors were lower than 6.0 \texttimes\ 10$^{-5}$% and 7.0 \texttimes\ 10$^{-5}$% for neutral atoms and monovalent cations, respectively. The IP results were strictly equal to numerical Hartree-Fock (NHF) calculations and comparable to some experimental values. For monovalent anions, the nonrelativistic total energies were better than the Slater-type functions results and the relative errors were lower than 0.05% when compared to NHF. The EA results were the same as those obtained with NHF calculations reported in the literature for heavier elements. For IP and EA, our results followed the same periodic tendency when compared with experimental data.

The effect of alkali metal chlorides and temperature on acid-hydrolysis residual pyrolysis products

Acid-hydrolysis residual (AHR) offers significant potential for harvesting chemical energy with simultaneous reduction of environmental pollution, providing carbon neutral (or even carbon negative) sustained energy production, energy security and alleviating social concerns associated with the wastes. In this study, the different effects of intrinsic and extrinsic K and Na were compared firstly. In addition, the effect of different content of alkali metal chlorides doped into AHR and temperature on pyrolysis products were investigated, especially for the phenolic products in bio-oil, along with the grey relational analysis. The results showed that KCl and NaCl promoted the generation of char and gas at the expense of the bio-oil yield. While, addition of KCl and NaCl could increase the yields of total phenolic species. Specifically, the yields of phenols and hydroxy phenols increased, while the guaiacols and syringols content decreased. The effect of KCl on the distribution of pyrolysis products and phenolic species was somewhat greater than NaCl, especially for bio-oil yield. The increasing of pyrolysis temperature would increase gas yield and reduce the char yield. While the bio-oil yield was peaked at 650 ℃. Besides, higher temperature restrained the generation of syringols and promoted the generation of phenols and hydroxy phenols. The grey relational analysis of KCl and temperature showed that KCl content was the major factor in the generation of bio-oil in pyrolysis process, while temperature played more notable role on the yields of total phenolic species, phenols, hydroxy phenols, guaiacols and syringols. The addition of alkali metal chlorides could promote the pyrolysis process and enhance the maximum lower heating value (LHV) of pyrolysis gas, especially the addition of NaCl. The optimal value of addition amount of KCl and NaCl was found to be 2 wt.% and 0.5 wt.%, respectively. Besides, the addition of KCl and NaCl could improve pore quality and activation of AHR pyrolysis char. Based on the pyrolysis products from cellulose, it can be proposed that cellulose has two main pathway depending on the alkali metal chlorides content.

Effect of Thickness Ratio in Piezoelectric/Elastic Cantilever Structure on the Piezoelectric Energy Harvesting Performance

The energy harvesting by utilizing the piezoelectric effect for the conversion of oscillatory mechanical energy to useful electrical energy has been promising for self-powered devices. The output power can be controlled by designing the size and shape of the constituents of the harvester. This study demonstrates the effect of Ti plate (elastic layer) thickness on the resonant frequency, neutral axis position, vibration amplitude and energy harvesting performance of the cantilever structured piezoelectric energy harvester (PEH). Here, the each harvester had the same dimensions of piezoelectric layer and the same proof mass position at the end of the cantilever while it had the different elastic layer thicknesses (70–300 μm). The analysis revealed that the output power showed the opposite trend in vibration amplitude with varying the elastic layer thickness. Among all of the PEHs, the configuration with the largest elastic layer thickness (300 μm) exhibited a maximum output power of 48 μW at 76 Hz under 0.2 g acceleration, despite of the smallest vibration amplitude and the highest resonant frequency. The outcomes suggest that the thickness ratio of the piezoelectric and elastic layers should be optimized to realize the best harvesting performance.

Optimal Hydropower Maintenance Scheduling in Liberalized Markets

Maintenance scheduling is an important and complex task in hydropower systems. In a liberalized market, the generation company will schedule maintenance periods to maximize the expected profit. This paper describes a method for hydropower maintenance scheduling suitable for a profit maximizing, price-taking, and risk neutral hydropower producer selling energy and reserve capacity to separate markets. The method uses the Benders decomposition principle to coordinate the timing of the power plant maintenance with the medium-term scheduling of the hydropower system, treating inflow to reservoirs and prices for energy and reserve capacity as stochastic variables. The proposed method is applied in a case study for a Norwegian watercourse, and results, in terms of maintenance schedules and computational performance, are presented and discussed.

First experimental measurements of a new fast ion driven micro-burst instability in a field-reversed configuration plasma

In modern field-reversed configuration (FRC) experiments (Binderbauer et al 2015 Phys. Plasmas 22 056110) at TAE Technologies, classical FRC instabilities are suppressed by advanced neutral beam injection and edge biasing methods, leading to high plasma confinement and fast ion pressure built-up which is comparable to the bulk plasma pressure. In some of these high performance FRC plasmas, a new macroscopically non-destructive fast ion driven micro-burst instability is observed as periodic small amplitude bursts with frequency down chirping in the diamagnetic drift frequency range, repeating about every 0.1 to 0.5 ms. The occurrence of these micro-bursts and burst-free operation can be controlled by changing the injected neutral beam energy. Major observed characteristics of this new instability are presented. Possible explanation of the phenomenon is suggested.

A rotary and reciprocating scintillator based fast-ion loss detector for the MAST-U tokamak.

The design and unique feature of the first fast-ion loss detector (FILD) for the Mega Amp Spherical Tokamak - Upgrade (MAST-U) is presented here. The MAST-U FILD head is mounted on an axially and angularly actuated mechanism that makes it possible to independently adapt the orientation [0°, 90°] and radial position [1.40 m, 1.60 m] of the FILD head, i.e., its collimator, thus maximizing the detector velocity-space coverage in a broad range of plasma scenarios with different q95. The 3D geometry of the detector has been optimized to detect fast-ion losses from the neutral beam injectors. Orbit simulations are used to calculate the strike map and predict the expected signals. The results show a velocity-space range of [4 cm, 13 cm] in gyroradius and [30°, 85°] in pitch angle, covering the entire neutral beam ion energy range. The optical system will provide direct sight of the scintillator and simultaneous detection with two cameras, giving high spatial and temporal resolution. The MAST-U FILD will shed light on the dominant fast-ion transport mechanisms in one of the world's two largest spherical tokamaks through absolute measurements of fast-ion losses.

Design and simulation of NBI heating system using high dense helicon plasma source for Damavand Tokamak

A neutral beam injection system by using standard COMSOL software is designed and simulated for plasma heating of small size Damavand tokamak. In context of theoretical model, the needed heat power for plasma heating of this tokamak to the specified temperature is estimated. The number of particles per second, power and energy of the neutral beam which is needed to reach the intended heat power are calculated. Based on these parameters, all sections of the neutral beam injection system such as the plasma source, the extractor, the accelerator, the neutralizer and the charge particles deflector system, are designed and simulated. A dense helicon plasma source, with nonuniform magnetic field configuration, is employed as a plasma source of the device. This helicon plasma source is designed and simulated according to the estimated parameters. Considering the beam optics and space-charge effects, an ion extractor system is simulated and designed for this device. This extractor system can extract an ion beam with current about 7.5 A. The simulation results show that a neutral beam with energy 4.45 KeV and particle current about 6.6 particle per second can be obtained from our designed NBI system. This neutral beam can heat the electrons of plasma to temperature 300 eV and ions to 150 eV. On the other hand, the results of the simulation indicate that our designed neutralizer system could neutralize about 90.58 percent of the initial input ions. In this context, the proper parameters (the neutral beam energy and power) of the NBI systems are calculated for heating of the electrons and ions of the plasma to temperature 1000 eV and 500 eV, respectively.

Urban Energy Systems and the Transition to Zero Carbon – Research and Case Studies from the USA and Europe

Local community interests in achieving carbon neutral energy supplies continues to rise whether these are cities, counties, universities, aggregated communities, or businesses themselves. Continued growth in this interest will be necessary to meet global carbon reduction targets. This paper considers some of the drivers and challenges faced by different communities in the USA and Europe, using the authors’ experience of different projects and initiatives to illustrate the points. The challenges identified include technical aspects of integrating existing systems with new renewable energy generation; short term financial pressures surpassing longer term environmental considerations; the inability to compare health, wellbeing and other social indicators with financial and environmental aspects; the difficulty in balancing the need for a viable business case with the needs of multiple stakeholders; and the need for transformational digital systems to become part of smart energy systems. An in-depth case study is provided for the University of California, Irvine campus which aims to reach carbon neutrality by 2025. The case study demonstrates the technical challenges of combining existing combined heat and power (CHP) systems with heating and cooling networks with local renewables. The results reveal that existing and new CHP and community thermal and power networks systems will need to operate in a much more dynamic fashion, which has implications on economics (reduced capacity factor, higher operating and maintenance costs) as well as on emission rates. This represents a challenge but innovative strategies are emerging to manage these dynamics including the use of thermal energy storage, experimental utility tariffs, improved part load operation of CHP systems, and the emergence of carbon capture techniques utilizing molten carbonate fuel cells.

Hydrogen battery using neutralization energy

Low-cost, non-toxic and environment-friendly electrochemistry is highly needed for clean energy storage technologies. Here we propose a most simple rechargeable pH differential hydrogen battery using neutralization energy as an efficient energy storage system to utilize renewable energy and waste acid/base. The overall battery reaction can be simplified as follow: 2 H+ + 2OH-←charge→discharge 2H2O. This proposed hydrogen battery can deliver a theoretical specific energy of up to 250 Wh kg−1 and a maximum energy density of up to 355 Wh L−1, very high values among aqueous battery systems. We show adding excessive amount of NaClO4 can lead to effective pH maintenance, higher coulombic efficiency, higher power and more stable cyclic performance at 9 mA cm−2. This work offers new opportunities to develop clean and high-energy battery technologies.