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An analysis of the peculiarities of the German Uranium Project (1939–1945) reveals that it was, in many ways, different from what one would expect. There was no work at all on a possible bomb, nor on plutonium. The reactor experiments were limited to subcritical systems and did not attempt to achieve the proclaimed goal of a self-sustaining chain reaction. The so-far identified deficits (lack of interest in Nazi circles, mismanagement, scientific mistakes, and deteriorating work conditions during the war) are relevant but not sufficient for explaining the peculiarities. We deduce that the scientists involved, and even the Heereswaffenamt (army ordnance), shied away from making progress, not only towards a bomb but even towards a reactor. They did not fail; they rather renounced a possible success in order not to provoke political interest in the development of a bomb. [ABSTRACT FROM AUTHOR]

In recent time, magnetically controlled shunt reactors are widely used in solving power quality problems. These reactors are designed to reduce system reactive power, control high super/special high voltage grid voltage, suppress power frequency, regulate overvoltage, eliminate generator excitation, dynamically compensate transmission line power charge, suppress secondary arc current, suppress system resonance. By using suitably designed silica plate core reactors at the input of the frequency converters in the electrical distribution system, the level of harmonic currents drawn from the electrical power distribution system can be reduced to certain rates. The core material, the air-gapped nature of the reactor core, and the sizing of the reactor have a great influence on the harmonic level of the current and its ability to reduce losses in the reactor. In this study, three reactors with different core materials and different air gap gaps are designed for a certain voltage value. Parametric analysis of the reactors designed to see the changes in inductance values depending on the load level has been made both theoretically and experimentally and using the Finite Element Method. As a result of the analysis, the inductance stability, losses and compliance of the reactors with the standards are presented. The reactor's magnetic circuit is modeled with ANSYS@Maxwell, realizing a solution based on this method. The magnetic circuit is simulated to see the behavior of the reactor. In addition, real-time verification of the designed alternating current reactor has been made. Optimum design was obtained by using different core materials and different core air-gaped tested experimentally. The effect of the air gap distance in the core on the magnetic field and inductance value was also obtained. [ABSTRACT FROM AUTHOR]

Chemoenzymatic epoxidation of olefin mediated by lipase is a green and environmentally friendly alternative process. However, the mass transfer barrier and lipase deactivation caused by the traditional organic–water biphasic reaction system have always been the focus of researchers' attention. To overcome these issues, we investigated the effects of reaction temperature and two important substrates (H2O2 and acyl donor) on the epoxidation reaction and interfacial mass transfer. As a result, we determined the optimal reaction conditions: a temperature of 30 °C, 30 wt-% H2O2 as the oxygen source, and 1 M lauric acid as the oxygen carrier. Additionally, by simulating the conditions of shaking flask reactions, we designed a batch reactor and added a metal mesh to effectively block the direct contact between high-concentration hydrogen peroxide and the enzyme. Under these optimal conditions, the epoxidation reaction was carried out for 5 h, and the product yield reached a maximum of 93.2%. Furthermore, after seven repetitive experiments, the lipase still maintained a relative activity of 51.2%. [ABSTRACT FROM AUTHOR]

A novel solid-state neutron and gamma radiation monitor-dosimeter based on biopolymer polylactic acid (PLA) is presented. The resulting detector (PLAD) technology takes advantage of property changes of the renewable PLA resin when subject to ionizing nuclear radiation. A simple yet rapid and accurate (±10%) low-cost (<$0.01/detector) mass loss upon dissolution (MLD) technique was successfully developed; MLD is based on a simple mass balance for discerning neutron and/or gamma doses using small (40 mg, ~4 mm diameter) ultra-low-cost (<$0.01) resin beads via dissolution in acetone. The GammaCellTM Co-60 irradiator, and the PUR-1 12 kW fission nuclear research reactor were utilized, respectively. Irradiation absorbed doses ranged from 1 to 100 kGy. Acetone bath temperature was varied from ~40 °C to ~54 °C. Results revealed a strong dependence of MLD on acetone bath temperature between neutron and gamma photon dose components; this allowed for the unique ability of PLAD to potentially perform as both a neutron-cum-gamma or as a gamma or neutron radiation dosimeter and intensity level detector. A linear trend is found for combined neutron and gamma radiation doses from 0 to 40 kGy when dissolution is conducted above 50 °C. The important potential ability to distinguish neutron from gamma radiation fields was scoped and found to be feasible by determining MLD at 45 °C. The potential was studied for simultaneous use as an in-core neutron and gamma monitor of an operating 3 GWt light-water reactor (LWR). Scoping tests were conducted with the pre-irradiated (@ 20 °C) PLAD resin beads followed by heating to in-core LWR coolant (300 °C) conditions for ~30 s corresponding to the time to reach ~40 kGy total doses in a typical 3 GWt LWR. MLD results were unaffected, indicating the exciting and unique potential for in situ (low-cost, accurate and rapid) simultaneous mapping of neutron and gamma radiation fluxes, related dosimetry, and fission power level monitoring. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen (H2) production is significant to overcome challenges like fossil fuel depletion and carbon dioxide emission, but its efficiency is still far below that which is needed for commercialization. Herein, we achieve long‐term stable H2 bubbling production from water (H2O) and lactic acid via visible‐light‐driven photocatalysis in a porous microreactor (PP12); the catalytic system benefits from photocatalyst dispersion, charge separation, mass transfer, and dissociation of O−H bonds associated with H2O. With the widely used platinum/cadmium‐sulfide (Pt/CdS) photocatalyst, PP12 leads to a H2 bubbling production rate of 602.5 mmol h−1 m−2, which is 1000 times higher than that in a traditional reactor. Even when amplifying PP12 into a flat‐plate reactor with an area as large as 1 m2 and extending the reaction time to 100 h, the H2 bubbling production rate still remains at around 600.0 mmol h−1 m−2, offering great potential for commercialization. [ABSTRACT FROM AUTHOR]

The U.S. Department of Energy (DOE) Nuclear Energy Advanced Modeling and Simulation (NEAMS) program has developed numerous physics solvers utilizing the open-source Multiphysics Object-Oriented Simulation Environment (MOOSE) framework for multiphysics reactor analysis. These solvers require input finite element meshes representing the discretized spatial domain. Typically, reactor analysts turn to licensed tools for the creation of reactor geometry meshes. Recently, open-source functionality has been added to the MOOSE framework to mesh common reactor geometries and improve MOOSE-based nuclear reactor application user workflows. The new functionality is primarily contained in the new Reactor module of MOOSE and includes support for hexagonal pins, assemblies, and cores, extended Cartesian geometry support, options for modeling static and rotating control drums within a hexagonal assembly, core periphery triangulation, and automatic tagging of pin, assembly, plane, and depletion regions for easier post processing of physics results. A set of reactor geometry mesh builder objects further streamlines the construction of hexagonal and Cartesian cores and allows mapping of materials to regions during mesh generation. The meshes produced with the MOOSE Reactor module may be used directly within MOOSE-based applications or exported as Exodus II files for use in other finite element solvers. The tools have been demonstrated and verified using a variety of NEAMS physics solvers on a range of reactor applications, including a sodium-cooled fast reactor core analysis using Griffin, a fast reactor assembly thermal deformation analysis using MOOSE Tensor Mechanics, and a heat pipe–cooled microreactor coupled analysis using Griffin, Bison, and Sockeye. MOOSE's Reactor module provides significant advantages compared to the use of external meshing tools when analyzing Cartesian and hexagonal reactor lattices using MOOSE-based applications: immediate accessibility (open-source) to the end user, low barrier to entry for new users, speed of mesh generation, volume preservation of meshed fuel pins, and simplification of analysis workflow when used in conjunction with MOOSE-based applications. [ABSTRACT FROM AUTHOR]

Through the current research status of plasma degradation pollutants at home and abroad, taking the generation of plasma to how to play a role as the main line, this paper explores the generation process and influencing factors of plasma, summarizes the common plasma generation devices, discusses and compares the degradation efficiency of organic, inorganic and solid pollutants, and the degradation principle and mechanism of different types of pollutants. It also discusses the current problems of plasma, and the future development direction of plasma degradation is prospected. [ABSTRACT FROM AUTHOR]

In some reactors, ammonia and its radiolytic product (H2) are used to scavenge the oxidizing species (H2O2, O2, and •OH). A reducing chemical environment is thus created and the pH of the coolant is regulated simultaneously. In the present study, the radiolytic behaviors of deoxygenated ammonia solution were studied in the γ-ray field. The impacts of N2 pressure, gas-liquid volume ratio, and temperature on deoxygenated ammonia solution radiolysis were investigated. The pH and the concentrations of residual ammonia, H2, and nitrogen oxides (NO2- and NO3-) were analyzed. The results revealed that the variation of N2 pressure (0.5~5.0 MPa) and gas-liquid volume ratio had no influence on the concentrations of residual ammonia and nitrogen oxides. NO2- and NO3- concentrations were approximately 1 mg/L at room temperature when the absorbed dose was 28.8 kGy. However, the apparent concentration of H2 significantly decreased with the N2 pressure and gas-liquid volume ratio. The loss fraction of ammonia considerably declined from 26.5% to 8.4% when the temperature increased from 25 to 200 ℃, demonstrating that the radiolysis of ammonia was suppressed at the elevated temperature. However, the concentrations of NO2- and NO3- increased to 34 and 3 times, respectively, at 200 ℃ compared to those at 25 ℃. In addition, a radiolysis model of ammonia-containing coolant was established in the present study. The maximum relative error between experimental data and calculation results at any temperature was 4.1%. The model was thereafter used to calculate residual ammonia concentration with the absorbed dose under different initial ammonia concentrations. The results revealed that it was necessary to replenish ammonia regularly when using it alone to inhibit oxidizing species.

The purpose of this work is to present a convenient design approach for metal hydride reactors that meet the specific requirements for hydrogen storage. Three methods from the literature, the time scale, the acceptable envelope, and the reaction front, are used to estimate the maximum thickness of the bed allowing for sufficient heat transfer. Further heat transfer calculations are performed within the framework of standardized heat exchanger via the homemade design software, to generate the complete geometry and dimensions of the reactor. LaNi5 material packed in tubular units based on conventional shell-and-tube heat exchanger is selected for analysis for an expected charging time of 500 s, 1000 s, and 1500 s. Apparently, the smaller the expected charging time, the smaller the bed thickness and hence the diameter of the tubular units. After comparison, the method of reaction front was adopted to output standard tube diameters and calculate the weight of the reactor. Significant weight differences were found to result from the varying wall thickness and number of tubes. In general, the shorter the expected charging time, the more tubular units with a small diameter will be built and the heavier the reactor. Fluent 2022 R2 was used to solve the reactor model with a tube diameter of 50 mm supposed to fulfill a charging time of 1500 s. The simulation results revealed that the reaction fraction reaches its maximum and the hydrogen storage process is completed at 500 s. However, because the calculation is conducted on meeting the heat exchange requirements, the average temperature of the bed layer is close to the initial temperature of 290 K and stops changing at 1500 s. The applicability of the method to the design of metal hydride reactors is thus confirmed by the temperature and reaction fraction judgment criteria.

This work describes the design, construction, and evaluation of a sequential discontinuous reactor with recirculation and aeration through a Herschel-type Venturi tube made of high-density polyethylene, coupled to a centrifugal pump. Four laboratory-scale prototypes were built, each with a volume of 8 L and a characteristic distance for venturi discharge. During the evaluation, temperature, pH, and dissolved oxygen were monitored. Also, the chemical oxygen demand (COD), the biological oxygen demand (BOD5), and the total suspended solids (TSS) in the clarified discharge liquid were determined. The BOD5 reduction efficiency registered values higher than 80%, while the COD reduction efficiency was around 60%. Thus, the action of microorganisms reduced the biodegradability factor, the BOD5, and contributed to the DQO through soluble microbial products. Besides, the increase of solids retention time (SRT) evidenced the increase in biomass settleability, which positively contributed to SBR operation. The results obtained support the implementation of the sequential batch reactor with mixing and aeration by recirculation through a Venturi as a technology for wastewater treatment. [ABSTRACT FROM AUTHOR]

Traditional industrial nitrogen fixation (NF) process uses the Haber-Bosch process which requires high temperature and high pressure, causing high energy consumption and serious pollution. Gliding arc plasma (GAP) combines the advantages of thermal plasma and cold plasma, which can efficiently produce active species and improve energy efficiency obviously. It has great application potential in the field of NF, and has received extensive attention in recent years. However, the research on NF via GAP is relatively fragmented at present. It is necessary to summarize the specific content. The research progress of NF via GAP at home and abroad in past 10 years is reviewed in this paper, mainly including GAP discharge mechanism, reactor design, process parameters and NF reaction mechanism. GAP discharge has B-G mode with breakdown following gliding discharge and A-G mode with continuous steady discharge. A-G mode discharge helps to improve nitrogen fixation efficiency. With the continuous development of GAP discharge technology, the electrode structure in GAP reactor has evolved from the traditional 2D blade structure to a variety of 3D cylindrical structures. Based on process optimization, GAP facilitates the vibrational excitation of N2 molecules, thereby promoting the splitting and transformation of N2 molecules. In the last, the research on NF through GAP is prospected. [ABSTRACT FROM AUTHOR]

Sulfuric acid, nitric acid, phosphoric acid and perchloric acid are usually used as catalysts for the preparation of organic peroxides. Due to the corrosion of strong acid to the equipment, the catalyst can not be reused, the amount of waste water after treatment is large, and the post-treatment cost is very high. The preparation of organic peroxides with heterogeneous catalysts has been paid more and more attention. Heterogeneous catalysts have the advantages of high activity, good stability and reusability, simple posttreatment, less equipment corrosion, and less environmental pollution. In this paper, on the basis of a brief introduction of the homogeneous preparation process of organic peroxides, the heterogeneous catalysts for the preparation of organic peroxides, including ion exchange resins, molecular sieves, phase transfer catalysts, metal oxides, polymer carrier catalysts and carbon-based support catalysts are summarized. The reactors and preparation processes are discussed, and the development direction of heterogeneous catalytic synthesis of organic peroxides is described. The study has strong reference value and guiding significance for understanding the progress in the preparation of organic compounds by heterogeneous catalysis, developing heterogeneous catalysts with excellent performance, and optimizing the production process of organic peroxides. [ABSTRACT FROM AUTHOR]

The latest technologies used in the production and processing of biodiesel were reviewed in order to improve the yield and quality of biodieseL Biodiesel has become a potential substitute for petrochemical diesel due to its good renewability and sustainability ・ The production and processing technology of biodiesel has a crucial impact on 让s output. By consulting relevant literature, the latest progress of biodiesel production and processing technology is comprehensively summarized, including raw materials, extraction, production methods, influencing factors, reactors and new processing technologies・ These studies show that the yield and quality of biodiesel can be guaranteed through the selection of raw materials and efficient production methods, providing a practical method for solving energy problems. [ABSTRACT FROM AUTHOR]

In order to explore the effect of temperature on the cracking reaction system of 1, 1, 2-trichloro-ethane, the thermodynamic simulation calculation of the system was carried out. The reactor module RG・ ibbs in Aspen Plus VI1 was adopted and combined with the sensitivity model analysis tool to calculate the equilibrium yield of each product at 150 ~300 °C under three conditions of single component, no polymerization reaction and polymerization reaction. The thermodynamic simulation results show that under standard cond让ions, the main reaction of dehydrochlorination of 1, 1, 2・trichloroethane to produce vinylidene chloride and the side reaction of producing cis-1, 2-dichloroethylene and trans-1, 2-dichloroethylene cannot be spontaneous・ The main and side reactions are endothermic reactions・ When the temperature is 150 °C, the equilibrium conversion of the side reactions to produce trans-1, 2-dichloroethylene and cis-1, 2-dichloroethylene is the lowest and the highest, respectively・ The equilibrium conversion of 1, 1, 2-trichlo-roethane cracking reaction is directly proportional to the temperature・ When the temperature reaches 300 °C, the equilibrium conversion is close to 100%. The thermodynamic properties of related substances were verified by the DMol-3 module of Materials Stu dio. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An iridium-192 miniature sealed source was produced by irradiation of 12 metal disks of natural iridium (470.5 mg) under a thermal neutron flux of 9.4 × 1013 n cm−2 s−1 during 200 h in Es Salam research reactor (Algeria). The preliminary activity was measured after 10 days decay time by a CAPINTEC type CRC-712 M dose calibrator, the given activity was 1.9 × 1011 Bq (5.2 Ci). To estimate source activity, a modeling of reactor core and irradiation container with the targets was made by MCNP5 code with and without iridium targets to evaluate the effect of the disturbance and reaction; the calculated activity using disturbed flux was comparable with that measured. A non-destructive test using 192Ir sealed sources with GammaMat TSI type B(U) projectors was carried out to evaluate the integrity of the weld joint at the bend of a carbon steel pipe. The weld quality of two plates; carbon steel and stainless steel was also evaluated. In terms of sensitivity, the resulting gamma images matched well and reported a real finding on the state of tested samples. [ABSTRACT FROM AUTHOR]

Heat management during the absorption/desorption process is a key aspect in improving the performance of large-scale hydrogen storage systems. In this article, the absorption and desorption performance of a multi-tubular hydride reactor is numerically investigated and optimized for 60 kg mass of LaNi 5 alloy. The 90% absorption with 7, 14, and 19 tubes is achieved in 985, 404, and 317 s with an overall reactor weight of 78.46, 88, and 88.2 kg, respectively. The 14-tube reactor performance is investigated by introducing the longitudinal fins inside the tubes. The reactor performance is enhanced by allocating fins into different pairs of half and full fins constrained by overall fin volume. A thermal resistance network model is presented to investigate the effect of fin distribution and coolant velocity on equivalent resistance of the metal hydride reactor. Storage performance obtained from numerical model validates the thermal resistance analysis from heat transfer viewpoint. With six full fins, 90% hydrogen absorption is achieved in 76 s. However, tubes with 6, 8, and 12 pairs of half and full fins require 74, 58, and 54 s, respectively. The 14-tube reactor with 8 pairs of half and full fins is used for quantifying the augmentation in the absorption performance in response to operating conditions (supply pressure and heat transfer fluid temperature). A design methodology is outlined for the development of a large-scale multi-tubular hydride reactor based on a heat transfer optimization strategy. • An optimum design methodology is provided for a multi-tubular hydride finned reactor. • A thermal resistance network model is presented to optimize the fin layout inside metal hydride tubes. • Twenty-five percent improvement in storage performance is observed with optimized longitudinal fins arrangement. • Reactor performance is evaluated in response to operating parameters. [ABSTRACT FROM AUTHOR]

Enhancement of sulfuric acid alkylation process efficiency in oil refineries by introducing a newly designed jet reactor into the process is proposed. The process efficiency increase has been proved by numerical modeling based on the obtained hydrodynamic flow rate distribution patterns in the apparatus. [ABSTRACT FROM AUTHOR]

A Smith-Dynamic Matrix Control(DMC)-PID(SDP)control method based on disturbance observer is devised for the temperature regulation of a reactor with high lag and nonlinear features. This results in poor system stability and low control precision. In the first place, because the reactor is prone to receiving external disturbances generated by external changes, which ultimately leads to a significant impact on the temperature inside the kettle, introducing the PID,DMC-PID control algorithm and Smith predictor combined with the compensation of large temperature hysteresis, the model structure of series control system, and the design of SDP series control to reduce the adjustment time and overshoot of the system. In addition, a disturbance observer that considers pure hysteresis linkages has been constructed for the reactor system that is impacted by uncertainty. In conclusion, the findings of the experiments indicate that the suggested control technique possesses strong stability and anti-disturbance performance.

Gamma spectrometry of the KAMINI reactor coolant lines at the selected spots/locations was carried out during 20kWt power and shutdown using portable spectrometers such as RIIDEye-X, RayMon (Cadmium Zinc Telluride), and hyper pure germanium.133Xe (81 keV),85m Kr (150 keV), and 135Xe (250 keV) isotopes could be identified. The spectra results did not indicate the presence of internal contamination due to any corrosion activation products such as 56Mn, 59Fe, 60Co, and fission products. The gamma radiation level observed during reactor power on the selected locations is only due to the fission product noble gases (FPNGs) and their short-lived radionuclides 88Rb and 138Cs generated and not any pipeline internal contamination.137Cs and trace quantities of 60Co were identified in the mixed bed regenerated liquid. The presence of 137Cs could be attributed due to the tramp fuel fissions.

Biological reactors are employed in industrial applications to break down organic waste. Here we consider the stability of an open loop CSTR, with a general growth rate function, having both a bacterial and substrate feed and a death rate. Reactors with a bacterial feed are important as every reactor after the first in a cascade will have both bacterial and substrate feeds. We show that stability of a critical point is related to the sign of the slope of the growth rate function, when no bacterial feed is present, and to the sign of the slope of a function, being the product of the growth rate function and a function involving the substrate and bacterial feed concentrations, when a bacterial feed is present.,,,,,,,,,,,,

The paper is devoted to the analytical inspection and parameterization of the dynamics of the world’s nuclear energy complex from the first selfsustaining chain reaction to the present day. The rapid development of nuclear power in the 1970s and 1980s slowed down significantly at the beginning of the third millennium. The dynamics of increasing operational capacities is a linear unfolding of the completed turn of the spiral of development. Almost 90 % of electricity in the nuclear power industry in 1970–2021 was generated by PWR and BWR light water reactors. It is expected that their technological resources will be exhausted by 99 % by 2077. If the current pace of development is maintained, the share of electricity generated by NPPs in the world by that time will decrease to 1,5 %. Nuclear power capacities in Europe and America are declining, while is developing in Asia, particularly in China, where almost 70 % of the nuclear power plants under construction are located. The rate of decline in uranium production indicates to by 2040 no more than half of the world’s nuclear fuel demand will be met. Safety and security of the nuclear energy complex are considerably decreasing with the growth of reactor capacity, and the discrepancy between the calculated and observed probabilities of a severe radiation accident reaches two orders of magnitude. As a result of current manifestation of great-power nuclear terrorism, the global nuclear safety and security system needs to be overhauled. Further development of the nuclear energy requires a “technological leap”. At present, there is no technology available for widespread implementation that could increase nuclear reactor capacity by an order of magnitude without compromising nuclear safety, especially considering that fusion reactor technology is unlikely to be widely implemented in the next few decades. A technological bridge between existing and future developments could serve small modular reactors which in the short term could mitigate the energy supply shortage.

There are a large number of local structural discontinuous zones in the form of cracklike defects in the reactor structure, due to the existence of the stress concentration at weld toes, the fatigue performance of the structure will be remarkably reduced. Therefore, the fatigue damage assessment in the cracklike discontinuous zone becomes an important issue in the nuclear reactor structure analysis. In this paper, based on the cracklike discontinuous zone caused by the welds between the closure head on the reactor pressure vessel and a penetrated pipe, two types of fatigue assessment methods were studied which are the general fatigue assessment methods considering the correction coefficient for welds and the fatigue reduction factor, and the fatigue assessment methods for the cracklike discontinuous zone in RCCMRx rules and RCCM rules. In RCCM rules, there are two approaches involved: the dedicated fatigue curve algorithm and the cyclic stress strain curve algorithm. For the cracklike fatigue assessment methods, singular elements were first used to calculate the stresses in the cracklike discontinuous zone, then the fatigue damage factors were calculated with the considerations of both the main cycles and subcycles of stresses, and the conservatism of the methods involved was compared. The results show that, compared with the general fatigue assessment methods, the stress concentration of the cracklike discontinuous zone can be better simulated by the cracklike fatigue assessment methods, and it is found that the stress level in the characteristic distance range is too high, and the stress curve is flat outside the characteristic distance, so the problem that the fatigue damage factors cannot be calculated caused by the stress singularity in the cracklike region tip, is effectively avoided. Compared with RCCM rules, the fatigue damage factors calculated by the RCCMRx method are higher due to the more conservative plastic correction. When the methods based on the RCCM rules were used, the fatigue damage factors calculated by the cyclic stress strain curve algorithm are slightly higher than that of the dedicated fatigue curve algorithm, indicating that the results are more conservative. Compared with the fatigue damage factors calculated by the cracklike assessment methods, the fatigue damage factors calculated by the correction coefficient for welds are lower. When the fatigue reduction factor gradually increases, the fatigue damage factors change from being less conservative to much more conservative. Therefore, when the fatigue reduction factor and the correction coefficient for welds cannot be accurately determined, there appear certain limitations of the engineering fatigue damage assessment methods based on the means of correction coefficients, and the cracklike fatigue assessment methods are more suitable for fatigue damage assessment in the cracklike discontinuous zone.

A novel reactor configuration combining two beds, a central fluidized bed and an annular mobile bed, was designed for the production of hydrogen and carbon nanofilaments via dry reforming of gases produced from the pyrolysis of plastic waste. This combination allows for easy recovery of these nanomaterials and, since the mixture of catalyst and carbon formed is continuously fluidized, it also prevents blockage. Understanding the hydrodynamics is crucial for choosing the optimal operating conditions. Thus, a cold mock-up unit of the same size has been built and used. Since the gases produced by plastic pyrolysis are mainly composed of unsaturated hydrocarbons, the prototype reactor setup has been operated using ethylene as a surrogate molecule. The preliminary experimental results of the reactor operation with ethylene obtained so far are very promising and confirm the operability of the process. Next step is to operate continuously for longer time and reach a production of 1kg/h of carbon nanofilaments.

The article presents the main provisions of the concept of the design of the SVBR-100 civilian reactor that meets the requirements for Generation IV nuclear technologies, which is being developed on the basis of a critically analyzed experience in developing and operating lead-bismuth-cooled reactor plants. The authors describe the current status of the project and the prospects for the use of such reactor plants in the nuclear power industry after demonstrating their reliability and safety in the operating conditions of a pilot commercial power plant.

Prompt capture gammas are an important part of the fission reactor gamma field. Because some of the structural materials after neutron capture can emit photons with high energies forming the dominant component of the gamma spectrum in the high energy region, the following study of the high energy capture gamma was carried out. High energy gamma radiation may play a major role in areas of the radiation sciences as reactor dosimetry. The HPGe measurements and calculations of the high-energy aluminum capture gamma were performed at two moderator levels in the VR-1 pool-type reactor. The result comparison for nominal levels was within two sigma uncertainties for the major 7.724 MeV peak. A larger discrepancy of 60% was found for the 7.693 MeV peak. The spectra were also measured using a stilbene detector, and a good agreement between HPGe and stilbene was observed. This confirms the validity of stilbene measurements of gamma flux. Additionally, agreement of the wide peak measurement in 7–9.2 MeV by stilbene detector shows the possibility of using the organic scintillators as an independent power monitor. This fact is valid in these reactor types because power is proportional to the thermal neutron flux, which is also proportional to the production of capture gammas forming the wide peak.

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thermochemical heat storage is a key technology to solve the mismatch between supply and demand of renewable energy and realize long-term energy storage. This work is concerned about a shell-and-tube thermochemical energy storage reactor and its aim is to address a challenge associated the low reaction rate from the tube centre of the reactor due to low thermal conductivity of the storage material. We proposed the integration of porous copper thermal bridges into the reactor and examined the performance enhancement with a validated mathematical model. By optimizing the structural parameters (numbers, thickness, and porosity) of the thermal bridge, the discharging rate and water temperature of the reactor can be maximized while the fan's electricity consumption is reduced. The results show that, with the addition of the thermal bridges with optimal structural parameters, the total heat release and water peak temperature lift can be increased by 11.33% and 39.75%, respectively, with the peak outlet water temperature reaching 59.02 °C. Reducing air velocity from 0.428 m/s to 0.107 m/s, the fan's electricity consumption can be reduced by 85.07% and 91.72% in the charging and discharging processes, which can be reduced by another 62.34% and 16.55%, respectively, after adding the thermal bridge. • Porous thermal bridges integrated into a shell-and-tube thermochemical reactor (TCR). • Optimal numbers, thickness and porosity of thermal bridges were obtained. • Fan's electricity consumption (FEC) proposed as TCR performance evaluating indicator. • Improvement of TCR reaction rate and reduction of FEC achieved simultaneously. [ABSTRACT FROM AUTHOR]

In this paper, a new method for measuring the neutron flux using proportional counters SNM-18 filled with 3Ne is studied. When developing equipment for automated measurement of the neutron flux of the research reactor VVR-K, the determining optimization criteria are power consumption, weight and dimensions. For this purpose, devices were used for automated measurement of the equivalent of soil moisture and the equivalent of snow water by the neutron component of cosmic rays. A number of experimental studies have been carried out to determine the optimal levels of supply voltages, the design of the device for operation at the VVR-K reactor has been changed. The main elements of the neutron detector design are a block of a hydrogen-containing moderator; a tube of a proportional thermal neutron counter; an amplifier and a microcontroller for analyzing the signal from the detector; a high-voltage power supply and a transmitter. Special software has also been developed for simultaneous control of detectors. Test measurements of the neutron flux were performed at the research reactor plant VVR-K INP using a Pu-Be neutron source, with an intensity of 1.8 *106 n/s. To reduce the neutron intensity for the safety of personnel and to reduce the load on the detector, the neutron source was placed inside a boron polyethylene collimator. [ABSTRACT FROM AUTHOR]

The review contains a comparative analysis of studies on the production of hydrogen and syngas based on the processes of partial oxidation of natural gas and other types of gas feedstock. The results presented in the literature show the high potential of non-catalytic autothermal processes of partial oxidation of hydrocarbons for the development of gas chemistry and energetics. The partial oxidation of hydrocarbons makes it possible to overcome such serious shortcomings of traditional syngas production technologies as technological complexity and high energy and capital intensity. The features of non-catalytic partial oxidation of hydrocarbon gases, the obtained experimental results and the results of kinetic modeling of various options for the implementation of the process, which confirm the adequacy of the kinetic mechanisms used for the analysis, are considered in detail. Examples of industrial implementation of processes based on partial oxidation and proposed alternative options for its organization are considered. Designs of reactors used to ensure stable conversion of rich mixtures of hydrocarbons with an oxidizer are presented. The possibility of obtaining other chemical products by partial oxidation of hydrocarbons is discussed. [ABSTRACT FROM AUTHOR]

Currently, biofuels represent a solution for the European Union in the transportation sector in order to reduce the greenhouse gas (GHG) emissions and the dependency of fossil fuels. Biodiesel from vegetable oils is a solution for countries with low GDP per capita to strengthen the internal agriculture, provide jobs, and reduce the use of fossil fuels. In this study, we model and simulate a temperature regulator designed for the biodiesel transesterification process in a discontinuous batch reactor, using methanol and a homogenous basic catalyst. The simulation was based on the kinetical model of the transesterification reaction and the mathematical model of the reactor. We considered molar ratios of alcohol/oil of 6:1 and 9:1, respectively, to shift the reaction equilibrium towards the production of fatty acid methyl esters. In the design of the simulation, the methanol boiling point was considered a restriction, therefore, temperatures below 65 °C were imposed. The results demonstrate that the increase in temperature results in a decrease in the reaction time and a higher yield, especially for the 6:1 molar ratio reaction, and that the optimum temperature for the batch reactor is of 60 °C. Automatic control improves the performance and costs of production. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels has led to a search for new methods of fuel and chemical production from biomass. One of the methods of converting biomass into valuable products is the process of pyrolysis. This process has been extensively researched in recent years due to the rising prices of energy and chemicals. This work contains basic information on the pyrolysis process concerning the individual components present in the biomass and the types of biomass used in the pyrolysis process. Particular attention was paid to sewage sludge, the management of which is a big challenge. The influence of the most important process parameters (temperature, heating rate, residence time of the solid and vapor, reaction atmosphere) on the pyrolysis products (char, oil, and gas) was presented. The paper presents an overview of the reactors used in the pyrolysis process, from slow to fast pyrolysis, together with their efficiency, advantages, and disadvantages. The analysis of the application of other thermochemical processes for producing the energy used in the process of pyrolysis and in the drying of the biomass was carried out. Two industrial-scale installations for the pyrolysis of sewage sludge were presented. [ABSTRACT FROM AUTHOR]

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Aerobic composting has been one of the fastest ways to fertilize soil products via organic decomposition under an oxygen-rich environment. Among them, the aerobic composting reactor can be one of the most important facilities during aerobic composting in recent years. However, some challenges are still remained in the aerobic composting reactor, including the long duration, low maturity homogenization, and utilization efficiency. In this study, an optimal vertical reactor of aerobic composting was designed with three independent layers using E-Discrete Element Method (EDEM) and Fluent simulation. An effective volume of 120 L was also obtained in the developed reactor. A series of simulations and experiments was implemented to verify the structural parameters. Each stage was also controlled to shorten the duration of the composting process in this reactor. The continuous process of feeding in and out of feedstocks was established, according to the actual requirement of the reactor during aerobic composting. ANSYS platform was finally used to verify the mixing system of the reactor. The results showed the maximum stress and deformation of the reactor were 75.288 MPa and 3.6804 mm during aerobic composting, respectively, fully meeting the high requirements of standard design. At the same time, the EDEM and Fluent simulation were then used to analyze the movement of materials during aeration and discharging. The results showed that the discharge rate of the reactor was 98.14% at the string speed of 20 r/min, and the gas volume fraction was above 90% during aeration. Better performance of the reactor was achieved in the discharge and aeration system during this time. A series of experiments was carried out on aerobic composting, particularly with the chicken manure and corn straw that were mixed at a ratio of 1:4 (dry weight basis). It was found that there was no significant difference in the temperature of the same layer during composting of the three batches (P>0.05). Specifically, the duration of the high-temperature period (higher than 50 °C) was maintained 9, 7 and 5 days, respectively, for the three raw materials. It infers that the composting fully met the ecological demand of harmless in this case. More importantly, the pH values were between 8.0 and 9.0, whereas, the electrical conductivity (EC) values were between 2.0 and 3.0 mS/cm during composting of three batches. There was a significant difference in the pH and EC values of each layer (P<0.05). However, there was no significance (P>0.05) at the same layer during the three batches. Moreover, the seed germination rates were also all above 100%. In addition, the degradation rates of volatile solid (VS) were 14.99%, 16.03%, and 13.24%, respectively, in the three batches. Hence, the stable properties of composting were achieved in the excellent performance of the developed reactor. Therefore, the improved composting reactor can be expected to serve as the aerobic composting reactor in the utilization of agricultural wastes. [ABSTRACT FROM AUTHOR]

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Food waste, which is the second largest component in landfills, generates excessive amounts of leachate and greenhouse gas. As a result, it has recently become a severe concern, mostly in the developing countries for its adverse impact on the environment. The addition of nutrients to organic waste limits the accumulation of volatile fatty acid (VFA) and accelerates the production of energy from food waste. The objective of the current study is to find out the effects of sludge addition on the decomposition and gas generation of separate components of food waste. This study was conducted for four combinations of reactors: two pairs containing meat and grain with the addition of a sludge content of 20% and 30%, respectively, as inoculum; another two pairs of reactors containing fruits and vegetables with a sludge content of 20% and 30%, respectively. Over the operation period, pH, volume, COD, and VFA tests were conducted for leachate while composition and volume measurements were done for the generated gas. Based on the results, it is observed that addition of sludge accelerated the decomposition of fruit and vegetable waste due to limited VFA accumulation compared to meat and grain. The maximum methane production was found in fruits and vegetable reactors at a rate of 6.7 L of methane per pound of food waste. For fruit and vegetable reactors, the CH4:CO2 ratio increased to as high as 8.5. On the other hand, for the meat and grain reactors, the increase in CH4:CO2 ratio was insignificant as they were in the lag phase. [ABSTRACT FROM AUTHOR]

The Argonauta research reactor at the Institute of Nuclear Engineering - IEN operates, under normal conditions, at powers ranging from 1.7 to 340 W, developing activities of a scientific-technological nature in the areas of neutron radiography, radionuclide production and conduction from experimental practices to graduate courses at CNEN research institutions and other Brazilian institutes of science and technology. During some security operations, the presence of investigators, students and/or operators inside and around the main hall of the Argonauta is required. Therefore, it is important to assess normal occupational exposure conditions when the reactor is in critical condition. This makes it possible to verify in greater detail the equivalent doses of ambient gamma radiation contained by the combustion of the fuel element inside the reactor room and in the surrounding areas, according to the Radiation Protection Plan (RPP) of this installation. In this work, a didactic activity was carried out to familiarize the students of the first period of the Master's Course in Nuclear Engineering, at the Military Institute of Engineering, with the procedures involved in the radiometric survey of the free, controlled and subsequent locations of this nuclear installation. This practice aims to identify the doses to which Occupationally Exposed Workers (OEW) and the general public are admitted, verifying compliance with regulatory requirements regarding the monitoring of environmental and local activities, as well as a comparison between the radiation monitors used.

Anhydrous ammonia (NH3) is a promising carbon-free fuel for internal combustion engines (ICEs) that can be generated from renewable energy sources and stored at high energy density. Ammonia is typically mixed with a small fraction of hydrogen (H2), which serves as combustion promoter to achieve stable combustion over a large range of engine operation. To overcome the difficulties of storing hydrogen, ammonia can be converted to hydrogen onboard by means of a catalytic reactor fed by waste thermal energy from the engine exhaust or by partial oxidation. This work explores an alternative method of producing hydrogen by partial oxidation of fuel-rich ammonia–air mixtures to hydrogen in an engine cylinder while generating useful work. Such an approach eliminates the need for costly catalyst materials and poses the possibility of a dedicated reforming cylinder to provide hydrogen for other cylinders in a multi-cylinder engine. Experiments were conducted in a single-cylinder spark-ignition (SI) engine with parametric sweeps of intake temperature, intake pressure, equivalence ratio, and spark timing. Experimental results show that 6% exhaust gas hydrogen concentration is attainable and 40% of the unburned fuel energy can take the form of hydrogen. Rich equivalence ratios produced higher concentrations of hydrogen and elevated intake temperatures extended the rich stable-operation limit of the engine. Low order chemical modeling yields insights into hydrogen production throughout the engine cycle, revealing that initial consumption of ammonia is advanced of hydrogen production and that competing elementary reactions for the formation and destruction of hydrogen drive its net quantity in the exhaust.