Upgrading Process Research Articles

Beam control system and output fine-tuning for safe and precise delivery of FLASH radiotherapy at a clinical linear accelerator.

We have previously adapted a clinical linear accelerator (Elekta Precise, Elekta AB) for ultra-high dose rate (UHDR) electron delivery. To enhance reliability in future clinical FLASH radiotherapy trials, the aim of this study was to introduce and evaluate an upgraded beam control system and beam tuning process for safe and precise UHDR delivery. The beam control system is designed to interrupt the beam based on 1) a preset number of monitor units (MUs) measured by a monitor detector, 2) a preset number of pulses measured by a pulse-counting diode, or 3) a preset delivery time. For UHDR delivery, an optocoupler facilitates external control of the accelerator's thyratron trigger pulses. A beam tuning process was established to maximize the output. We assessed the stability of the delivery, and the independent interruption capabilities of the three systems (monitor detector, pulse counter, and timer). Additionally, we explored a novel approach to enhance dosimetric precision in the delivery by synchronizing the trigger pulse with the charging cycle of the pulse forming network (PFN). Improved beam tuning of gun current and magnetron frequency resulted in average dose rates at the dose maximum at isocenter distance of >160 Gy/s or >200 Gy/s, with or without an external monitor chamber in the beam path, respectively. The delivery showed a good repeatability (standard deviation (SD) in total film dose of 2.2%) and reproducibility (SD in film dose of 2.6%). The estimated variation in DPP resulted in an SD of 1.7%. The output in the initial pulse depended on the PFN delay time. Over the course of 50 measurements employing PFN synchronization, the absolute percentage error between the delivered number of MUs calculated by the monitor detector and the preset MUs was 0.8 ± 0.6% (mean ± SD). We present an upgraded beam control system and beam tuning process for safe and stable UHDR electron delivery of hundreds of Gy/s at isocenter distance at a clinical linac. The system can interrupt the beam based on monitor units and utilize PFN synchronization for improved dosimetric precision in the dose delivery, representing an important advancement toward reliable clinical FLASH trials.

A novel process based on powder carriers demonstrates robustness in nitrogen and phosphorus removal from real municipal wastewater

The development of efficient and low-consumption wastewater upgrading process is currently at the forefront of the wastewater treatment field. In this study, a novel wastewater treatment process based on powder carriers was proposed. Three systems, namely the activated sludge (AS) system, powder carrier (PC) system, and moving bed biofilm reactor (MBBR) system, were established and operated for over 140 days to treat real municipal wastewater. The characteristics and differences between the three systems were comprehensively investigated. The results suggested that the PC system exhibited notable advantages in nitrogen and phosphorus removal, especially under high influent load and low aeration conditions. The PC system, characterized by a higher nitrification rate compared to the MBBR system and a higher denitrification rate compared to the AS system, contributed to the stable nitrogen removal performance. The particle size of the zoogloea increased under the linkage of the powder carriers, and the mean size of micro-granules reached 170.88 μm. Large number of hydrophobic functional groups on sludge surface, coupled with increased protein content in EPS, further promoted sludge aggregation. Micro-granules formation improved settling performance and enhanced the abundance and activity of functional microbes. A significant enrichment in denitrifying bacteria and denitrifying phosphorus accumulating bacteria was observed in PC system. Up-regulation of the napA, narG, and nosZ genes was responsible for efficient nitrogen removal of the PC system. Moreover, a higher abundance in polyphosphate phosphotransferase (2.11 %) was found in PC system compared with AS and MBBR systems. The increase in the enzymes associated with poly-β-hydroxybutyrate (PHB) synthesis metabolism in PC system provided the energy for denitrification and phosphorus removal processes.

Catalytic Upgrading of Rice Straw Bio-Oil via Esterification in Supercritical Ethanol over Bimetallic Catalyst Supported on Rice Straw Biochar

This research explores the enhancement of bio-oil quality through upgrading with the magnetic bimetallic oxide (CuO-Fe3O4) catalysts supported on activated rice straw biochar (AcB). These catalysts were employed in a supercritical ethanol-based upgrading process. Various characterization techniques, including elemental analysis, Fourier transform infrared (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), were utilized to characterize the prepared catalysts. This study revealed significant improvements in the physical characteristics and chemical composition of the bio-oil, with an increase in the heating value (HHV) from 21.3 to 32.1 MJ/kg. Esterification and transesterification were identified as key reactions contributing to this improvement. Notably, the pH of bio-oil increased from 4.3 (raw bio-oil) to 5.63 (after upgrading), signifying reduced acidity. The analysis of the bio-oil’s chemical composition highlighted a decrease in oxygen content and an increase in carbon and hydrogen content. At the optimum conditions, the application of supercritical ethanol proved to be an efficient method for enhancing the bio-oil’s properties. A crucial transformation occurred during the upgrading process and more than 90% of carboxylic acids were converted into esters, primarily ethyl acetate at the optimal conditions. This study has demonstrated the effective enhancement of raw bio-oil from rice straw through the utilization of carbon-based bimetallic oxide catalysts in a supercritical upgrading procedure.

An OTA Upgrade Differential Compression Algorithm Based on Suffix Array Induced Sorting and BsDiff Methods

As the scale and complexity of software for industrial equipment increases, the risk of defects being introduced into the software also increases. Over-the-air (OTA) technology eliminates software defects by regularly updating and maintaining the software equipment. However, downloading an upgraded file is time-consuming. The differential compression algorithm can rapidly complete OTA software upgrades. To solve the low-efficiency problem of suffix array sorting in the BsDiff algorithm, a fusion algorithm based on the suffix array induced sorting and BsDiff methods was proposed to reduce the time consumption in the OTA upgrade process. The execution of the difference algorithm in the cloud was simulated using bench experiments. Subsequently, the function and performance of the proposed algorithm were experimentally evaluated. The results showed that the optimized algorithm could save more than 35% of the time compared to the original algorithm, which improved the OTA upgrade efficiency to a certain extent.

Sustainable development and multi-aspect analysis of a novel polygeneration system using biogas upgrading and LNG regasification processes, producing power, heating, fresh water and liquid CO2

Considering biogas upgrading to feed energy systems and its significant impact on the biogas energy density, a novel polygeneration system utilizing biogas from landfill waste is designed, simulated, and studied in this paper. The primary innovation is to design a biogas upgrading technology for a novel multigeneration system using a thermal matching approach. This system is capable of simultaneously generating power, providing heating, producing fresh water, and extracting liquid carbon dioxide in an environmentally sustainable manner, thus resulting in reduced environmental impacts. For this purpose, a cryogenic separation system based on liquefied natural gas cold utilization is employed for biogas upgrading and biomethane separation. The proposed process also consists of a Kalina cycle, an organic Rankine cycle, a multi-effect desalination technology, and a heating provider unit. This system is simulated within the Aspen HYSYS software and is undergone a comprehensive analysis from the viewpoints of energy, exergy, environmental, and economic. The results indicate that the proposed structure achieves energy and exergy efficiencies of 80.91% and 43.76%, respectively. Environmental assessment reveals that the emission intensity is 90.43% lower in polygeneration mode compared to power generation mode, and the system’s net emission is equal to 23,041.51 kg/h. The economic evaluation demonstrates that the total unit cost of products is minimized in polygeneration operation (1.84 $/GJ), while it is highest in power generation condition (7.564 $/GJ). The investigations show that when a system is modified from a single generation to polygeneration, all thermodynamic, economic, and environmental indicators face an improvement.

SGXonerate:Finding (and Partially Fixing) Privacy Flaws in TEE-based Smart Contract Platforms Without Breaking the TEE

TEE-based smart contracts are an emerging blockchain architecture, offering fully programmable privacy with better performance than alternatives like secure multiparty computation. They can also support compatibility with existing smart contract languages, such that existing (plaintext) applications can be readily ported, picking up privacy enhancements automatically. While previous analysis of TEE-based smart contracts have focused on failures of TEE itself, we asked whether other aspects might be understudied. We focused on state consistency, a concern area highlighted by Li et al., as well as new concerns including access pattern leakage and software upgrade mechanisms. We carried out a code review of a cohort of four TEE-based smart contract platforms. These include Secret Network, the first to market with in-use applications, as well as Oasis, Phala, and Obscuro, which have at least released public test networks. The first and most broadly applicable result is that access pattern leakage occurs when handling persistent contract storage. On Secret Network, its fine-grained access pattern is catastrophic for the transaction privacy of SNIP-20 tokens. If ERC-20 tokens were naively ported to Oasis they would be similarly vulnerable; the others in the cohort leak coarse-grained information at approximately the page level (4 kilobytes). Improving and characterizing this will require adopting techniques from ORAMs or encrypted databases. Second, the importance of state consistency has been underappreciated, in part because exploiting such vulnerabilities is thought to be impractical. We show they are fully practical by building a proof-of-concept tool that breaks all advertised privacy properties of SNIP-20 tokens, able to query the balance of individual accounts and the token amount of each transfer. We additionally demonstrate MEV attacks against the Sienna Swap application. As a final consequence of lacking state consistency, the developers have inadvertently introduced a decryption backdoor through their software upgrade process. We have helped the Secret developers mitigate this through a coordinated vulnerability disclosure, after which their state consistency should be roughly on par with the rest.

Marine ecological restoration strategies of coastal nuclear power plants in China

Low-carbon and green development model is the choice for responding to climate change. Under the dilemma between ever-growing energy demand and the associated environmental issues, nuclear power is one of the low-carbon and high-efficient energy options which compared to wind power and solar power. It is the only stable power source that can replace fossil energy on a large scale at present and even in the future. This paper briefly describes the operational risks of coastal nuclear power plants (CNPPs) and the upgrade process of nuclear reactors, systematically analyzes and summarizes the ecological environment problems, risk problems and ecological restoration and protection strategies in the construction and operation of CNPPs, including coastal wetland ecological environment, marine ecological environment, and the risk prevention measures for cooling water source. The results show that ecosystem restoration by human does not make up for the weakening of the ecological carrying capacity and ecosystem away from its baseline, nonetheless, the restoration of important wetland habitats is conducive to the improvement of the functions of key marine ecosystems and the maintenance of marine biodiversity.

Catalytic hydrodeoxygenation of benzoic acid as a bio-oil model compound: Reaction and kinetics using nickel-supported catalysts

The development of technologies for the bio-oil upgrading process is a crucial step towards achieving sustainable energy production. This study investigates the effects of support properties during the hydrodeoxygenation (HDO)...

Research on the impacts of GPF on RDE emission behaviors

In this research, RDE tests were carried out on a pre-China 6 TGDI vehicle in the two cases of installing or not installing GPF to explore the impacts of GPF on RDE emission behaviors. The results indicated that the GPF can effectively filter PN emissions, especially at low speed, high load engine operating conditions, where the PN emissions can be reduced to about 1/200 of the original emissions. For TGDI vehicles, the installation of GPF can reduce the RDE PN emissions by more than 30 times, which indicates that the GPF is the key post-processing device for TGDI vehicles to meet the China 6 regulation. And in the upgrade process of China 5 vehicles to China 6 vehicles, especially for TGDI vehicles, the engine, the post processor and the turbocharger all needs re-calibrating or re-matching to concur a series of problems the back pressure raise caused by the installation of GPF, which may bring deterioration of engine combustion process, decrease of catalyst temperature and similar conditions that will worsen the vehicle emissions.

Risk Minimization in Scale-Up of Biomass and Waste Carbon Upgrading Processes.

Improving the odds and pace of successful biomass and waste carbon utilization technology scale-up is crucial to decarbonizing key industries such as aviation and materials within timelines required to meet global climate goals. In this perspective, we review deficiencies commonly encountered during scale-up to show that many nascent technology developers place too much focus on simply demonstrating that technologies work in progressively larger units ("profit") without expending enough up-front research effort to identify and derisk roadblocks to commercialization (collecting "information") to inform the design of these units. We combine this conclusion with economic and timeline data collected from technology scale-up and piloting operations at the National Renewable Energy Laboratory (NREL) to motivate a more scientific, risk-minimized approach to biomass and waste carbon upgrading scale-up. Our proposed approach emphasizes maximizing information collection in the smallest, most agile, and least expensive experimental setups possible, emulating the mentality embraced by R&D across the petrochemical industry. Key points are supported by examples of successful and unsuccessful scale-up efforts undertaken at NREL and elsewhere. We close by showing that the U.S. national laboratory system is uniquely well equipped to serve as a hub to facilitate effective scale-up of promising biomass and waste carbon upgrading technologies.

Optimization of flotation conditions in the beneficiation of PGMs tailings

For several years, mining waste has shown a negative impact on both the environment and human health. The mining industry remains the backbone of the economic growth. Different technologies have been implemented to beneficiate and recover platinum group metals from tailings. The recycling of tailings has been a point of research interest due to their extensive applications. Flotation has been the primary process of upgrading and recovering PGMs. The focus of this study was to optimize flotation conditions in the beneficiation of PGMs for particular small-scale mine tailings. This was done to obtain the most favourable conditions for the small-scale mine tailings to improve operating conditions of specific particle sizes. PGMs tailings obtained from a small-scale mine were characterized using XRD, XRF, SEM/EDS, and ICP – OES to understand the properties of the tailings prior to mineral processing. Flotation batch tests were conducted. The results showed that the chosen particle size was 75 µm, and the favorable reagent dosages were 150 g/Mg and 100 g/Mg for SIBX (collector) and Starch(depressant), respectively. At favourable conditions, the recovery was 65.75% (Pt = 70.38%, Pd = 59.33%, Ru = 34.56%), and the grade was 31.46 g/Mg (Pt = 21.43 g/Mg, Pd = 9.62 g/Mg, Ru = 0.41 g/Mg). It can be concluded that all the flotation parameters are related; lower particle sizes yield high recoveries and better grades due to the exposure of the particle surface to the reagents responsible for the flotation of the PGMs. It was observed that the high collector dosages produce high recoveries with low grades of PGMs. High depressant dosages produce low recoveries with high grades of PGMs. The relationship between the collector and the depressant is of essential importance in the flotation process.

Polyoxometalate as an Effective Catalyst for Catalytic Lignin into Value‐Added Molecules

AbstractLignin, an inherently heterogeneous arylpropanoid polymer, presents a unique resource for the sustainable manufacture of aromatic chemicals and fuels. Recently, numerous catalytic strategies for lignin valorization have been explored. Polyoxometalates (POMs), with their distinctive structures enabling control of redox processes in lignin conversion, have been of particular interest. However, a comprehensive assessment of this emerging field of study is currently missing. This paper aims to fill this gap with a detailed review of the use of POMs for catalytic lignin conversion into value‐added compounds. This review delves into various catalytic lignin conversion techniques, including thermal catalysis, electrocatalysis, and tandem processes for lignin separation, depolymerization, and upgrading. Moreover, we highlight innovative investigations utilizing polyoxometalate‐ionic liquids (POM‐ILs), POM‐deep eutectic solvents (POM‐DESs), and solidification or immobilization techniques for POMs as lignin valorization catalysts. Lastly, we discuss the future prospects and challenges in the domain of POM catalytic lignin conversion.

Key Criteria Influencing Stakeholders’ Decision-making about PB Continuation: The Case of the Czech Republic

Abstract Participatory budgeting (PB) is a modern trend involving citizens in decisions on distributing public resources. Assuming that the identified drawbacks of PB are described as internal and external factors, simple criteria were developed to predict the fate of PB. These criteria reflect stakeholders’ decisions about PB continuation in the future. Using panel data between 2017-2022 from the Czech Republic, it appears that the selected criteria were evaluated as an upgrading process, signalling the continuation of PB. However, this does not mean abandoning the process in the case of downgrading. The results indicate a certain probability for upgrading PB to continue, while the fate of downgrading PB is indeterminate and could depend on other factors. In the case of new governance after an electoral change, using the criteria could help explain the actual situation regarding the interest of stakeholders in PB.

Experimental data driven thermodynamic modelling and process simulation for biogas upgrading

Data driven thermodynamic models has a great potential to add value to the accuracy of simulation processes. In this study experimental data driven e-NRTL activity coefficient model is used to evaluate the behavior of MEA/AMP and MDEA/AMP aqueous systems for biogas upgrading. The vapor liquid equilibrium (VLE) experimental data is used for regression of the electrolyte pair parameters of e-NRTL activity coefficient model, which were then used to design the process for biogas upgrading by using Aspen Plus in combination with MATLAB. Experiments have been carried out for CO2 solubility as a function of CO2 partial pressure (PCO2) at different amine blending ratios such as 9/21/70, 15/15/70, and 21/9/70 (w/w/w percent) for each MEA/AMP/H2O and MDEA/AMP/H2O systems at a wide temperature range of 323.15–383.15 K. The importance of regressed parameters was confirmed through global sensitivity analysis (GSA) using Monte Carlo simulation. The local sensitivity analysis (LSA) and GSA for biogas upgrading process based on data driven thermodynamic modeling have been carried out in terms of the biomethane purity, reboiler heat duty, and methane slip. Finally, the optimal process parameters were found through multi-objective optimization (MOO) for developed biogas upgrading process.

The swelling induced choline alkali-urea (SICAU) process for sustainable crop straw upgrading

Upgrading lignocellulosic biomass into value-added product forms has been attractive but challenged by its structural recalcitrance and heterogeneity. Prevalent fractionation techniques employ aggressive chemical solvents or catalysts to cleave lignin-carbohydrates bonds with the purpose of dissolution ability enhancement. This work tailored the swelling induced choline alkali-urea (SICAU) process to fractionate rice straw with the powerful choline alkali-urea (ChOH-Ur) deep eutectic solvents (DES) with the preservation of lignin-carbohydrates bonds, thus the super high yield of high-value lignin-carbohydrates complexes (LCCs) was co-produced together with highly hydrolysable cellulose and ethanol-insoluble xylooligosaccharides (XOSs) fractions. Results showed that rather high cellulose recovery (87.3 %-100 %) was obtained with nearly 100 % cellulose to glucose conversion. Optimized LCCs yield of 34.3 % was achieved with 50 % choline alkali-urea concentration and 4 h cooking time, along with the corresponding yield of 10.2 % XOSs during the DES conversion process. The LCCs linkages were 0.06–0.16/100 Ar depending on cooking conditions. The proposed integrated SICAU process realized the complete upgrading of rice straw into three value-added products, which showed a very different working profile with prevalent systems that usually fractionated lignocellulose into cellulose, lignin, and hemicellulose. Therefore, the SICAU process could extract higher value from lignocellulose towards a more sustainable lignocellulose biorefinery.

Context‐based transfer learning for low resource code summarization

AbstractSource code summaries improve the readability and intelligibility of code, help developers understand programs, and improve the efficiency of software maintenance and upgrade processes. Unfortunately, these code comments are often mismatched, missing, or outdated in software projects, resulting in developers needing to infer functionality from source code, affecting the efficiency of software maintenance and evolution. Various methods based on neuronal networks are proposed to solve the problem of synthesis of source code. However, the current work is being carried out on resource‐rich programming languages such as Java and Python, and some low‐resource languages may not perform well. In order to solve the above challenges, we propose a context‐based transfer learning model for low resource code summarization (LRCS), which learns the common information from the language with rich resources, and then transfers it to the target language model for further learning. It consists of two components: the summary generation component is used to learn the syntactic and semantic information of the code, and the learning transfer component is used to improve the generalization ability of the model in the learning process of cross‐language code summarization. Experimental results show that LRCS outperforms baseline methods in code summarization in terms of sentence‐level BLEU, corpus‐level BLEU and METEOR. For example, LRCS improves corpus‐level BLEU scores by 52.90%, 41.10%, and 14.97%, respectively, compared to baseline methods.

Mineralogical Characteristics of Baima Vanadium Titanomagnetite during Magnetic Separation Upgrading

The Baima vanadium titanomagnetite deposit, located in the Panzhihua-Xichang (Panxi) metallogenic belt in China, is one of the super-large deposits in the region. The titanomagnetite upgrading process involves grinding the raw ore followed by magnetic separation. To determine the processing characteristics of the ore and assess the upgrading process, this study employs various methods and techniques, including the X-ray fluorescence spectrometer (XRF), chemical element analysis, the electron probe microanalyzer (EPMA), and the advanced mineral identification and characterization system (AMICS). The results show that the Fe grades in the upgraded raw ore, upgraded concentrate, and upgraded tailings are 55.68%, 57.89%, and 15.62%, respectively. After upgrading, the titanomagnetite content increased from 77.41% to 82.10%, and the Fe distribution in titanomagnetite also increased from 91.05% to 93.14%. In the upgraded raw ore, titanomagnetite particles followed a normal distribution, with 50.44% in the 38–74 μm range. In the upgraded concentrate, titanomagnetite was concentrated in the 19–38 μm range. Based on EPMA data, the theoretical Fe grade in titanomagnetite was calculated to be 65.08%, indicating the potential for further improvement through the upgrading process. This study elucidates the mineralogical characteristics during the vanadium titanomagnetite upgrading, providing a theoretical basis to further enhance the Fe recovery rate.

Catalytic transfer hydrogenation of CO2 to formic acid with glycerol as the hydrogen donor over Ru-REUSY catalysts

In this work, a "hydrogen-free" strategy based on the ruthenium (Ru) modified REUSY molecular sieve catalysts was proposed, which can promote CO2 catalytic transfer hydrogenation using endogenous hydrogen induced by glycerol dehydrogenation. As the active component, Ru can not only act on the dehydrogenation reaction with glycerol, but also promote the hydrogenation reaction of CO2. Comparison experiments confirmed that under conditions of 200 °C, 36 h, and 7.92 g KHCO3, the reaction could obtain the highest yields over 10 wt.% Ru-deAl(5 h)-REUSY. The yields of formic acid and lactic acid were 19.81 % and 6.13 % respectively. In addition, when replacing the carbon source from KHCO3 to CO2 (dry ice), formic acid and lactic acid yields over 10 wt.% Ru-deAl(5 h)-REUSY catalysts were further improved, reaching 64.14 % and 17.13 %, respectively. This work demonstrated the feasibility of the "hydrogen-free" upgrade process realizing the catalytic transfer hydrogenation of CO2 into formic acid with glycerol as hydrogen donor.

Oxidative Depolymerization of Polyphenylene Oxide into Benzoquinone.

Poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is one of the most important engineering plastics commonly utilized in various fields. Herein, chemical recycling of PPO was performed via oxidative depolymerization to form 2,6-diemthyl-p-benzoquionone (26DMBQ) as a sole aromatic product in 66 % yield using nitronium ions (NO2 + ) as a mild oxidant. Mechanistic studies revealed that PPO is oxidized by NO2 + generated from the combination of a silicotungstic acid and nitrate salts, and then subsequently attacked by H2 O to achieve C-O bond cleavage, resulting in the formation of 26DMBQ, which was sublimed at the headspace of the reaction vessel in pure form. 26DMBQ was applied to polymerization with dianilines to form polyimides. Thus, an upgrade recycling process of PPO was demonstrated.

In-situ catalytic upgrading of bio-oils from rapid pyrolysis of torrefied giant miscanthus (Miscanthus x giganteus) over copper‑magnesium bimetal modified HZSM-5

In this study, fast pyrolysis of both raw and torrefied giant miscanthus (GM) is investigated in detail. It is found that the pyrolysis of torrefied GM results in higher distribution of phenols and aliphatic compounds in bio-oil with lower moisture content. To further improve the bio-oil quality, catalytic upgrading process of the bio-oil from the torrefied GM over copper‑magnesium (CuMg) bimetal doped zeolites is also investigated. As a result, a highest yield of aromatic hydrocarbons of 63.1% favoring in higher monoaromatic hydrocarbons such as benzene, toluene and xylene in the upgraded bio-oil is obtained as GM-300 is used as feedstock and HSZ-Cu 2:1 Mg as the catalyst. It is found that CuMg doping can not only enhance catalytic activity of zeolite but also maintain relatively low coke deposition and improve the catalyst reusability. Besides, the spent catalysts are easily regenerated only by a facile calcination way, and the regenerated catalyst shows almost the same activity as the initial one.