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Showing records 318 to 342 of 1817. [First] Page: 1 10 11 12 13 14 15 16 17 18 Last
A Real-Time Resource Dispatch Approach for Edge Computing Devices in Digital Distribution Networks Considering Burst Tasks
Jing Xu, Juan Li, Liang Zhang, Chaoming Huang, Hao Yu, Haoran Ji
August 23, 2024 (v1)
Keywords: burst tasks, digital distribution network, edge computing, real-time processing mechanism, resource rescheduling
Edge computing technology can effectively solve huge challenges posed by the large number of terminal devices accessing and massive data processing in digital distribution networks. Burst tasks, such as faults and data requests from the cloud, can occur at any time for edge computing devices in distribution networks. These tasks are unpredictable and usually hold the highest priority and must be completed as soon as possible. Although resources can be reserved partially at each period in the pre-scheduled operation plan, they may still be insufficient to handle burst tasks adequately. A real-time resource dispatch approach for burst tasks is developed in this study to address the above problems. The concept of flexibility for edge computing devices is presented, determining the real-time dispatch duration. Real-time resource dispatch and task handling processing are analyzed in detail, considered as task real-time dispatch models, computation process real-time dispatch constraints, and... [more]
Development of a CaCO3 Precipitation Method Using a Peptide and Microwaves Generated by a Magnetron
Fumihiro Kayamori, Hiroyuki Togashi, Natsumi Endo, Makoto Ozaki, Kan Hirao, Yonejiro Arimoto, Ryuji Osawa, Takaaki Tsuruoka, Takahito Imai, Kin-ya Tomizaki, Tomohiro Umetani, Nobuhiro Nakanishi, Kenji Usui
August 23, 2024 (v1)
Subject: Biosystems
Keywords: CaCO3 mineralization, irradiation direction, magnetron oscillator, microwave, peptide
Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed to investigate the effects of microwaves on calcium carbonate biomineralization as a model biochemical process. A magnetron oscillator was used to generate 2450 MHz microwaves because magnetrons are relatively inexpensive and widespread. We conducted transmission electron microscopy (TEM), atomic force microscopy (AFM), TEM-electron energy-loss spectroscopy (EELS), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) measurements to analyze the calcium carbonate precipitates. Our findings showed the formation of string-like precipitates of calcium carbonate upon microwave irradiation from one direction, similar to those obtained using a semicondu... [more]
Anaerobic−Aerobic Treatment of Fruit and Vegetable Wastes and Municipal Wastewater
Sergio Esteban Vigueras Carmona, Mariana García Valdés, Maura Selene Meléndez Rico, María Monserrat Montes García
August 23, 2024 (v1)
Keywords: activated sludge, anaerobic digestion, leachates, UASB
Waste management in large urban centers is one of the main challenges for public administration. Two of the most abundant wastes in cities are waste solid and municipal wastewater (MWW). Their management can be optimized if they are treated together. This work analyzed an anaerobic−aerobic system for the treatment of fruit and vegetable wastes (FVWs) and MWW. Firstly, FVWs were collected and characterized; once in the laboratory, they were placed in a tank with the MWW, aiming at transferring to the water those solids with a particle size below 105 µm; then, they were separated by sieving. The mixture of MWW and FVWs with a particle size below 105 µm was fed into an up-flow anaerobic sludge reactor (UASB); in the latter, dissolved and suspended organic matter was transformed into methane and carbon dioxide. The water that left the UASB was sent to be post-treated in an activated sludge reactor (ASR). The chemical oxygen demand (COD) was used as an evaluation parameter of the anaerobic−... [more]
Numerical Simulation and Field Experimental Study of Combustion Characteristics of Hydrogen-Enriched Natural Gas
Chen Sun, Tiantian Wang, Pengtao Wang, Yi Zhang, Chong Cui, Yanghui Lu, Wei Liu, Yangxin Zhang, Yang Zhang
August 23, 2024 (v1)
Keywords: combustion characteristics, field tests, hydrogen-enriched natural gas, numerical simulation
For the safe and efficient utilization of hydrogen-enriched natural gas combustion in industrial gas-fired boilers, the present study adopted a combination of numerical simulation and field tests to investigate its adaptability. Firstly, the combustion characteristics of hydrogen-enriched natural gas with different hydrogen blending ratios and equivalence ratios were evaluated by using the Chemkin Pro platform. Secondly, a field experimental study was carried out based on the WNS2-1.25-Q gas-fired boiler to investigate the boiler’s thermal efficiency, heat loss, and pollutant emissions after hydrogen addition. The results show that at the same equivalence ratio, with the hydrogen blending ratio increasing from 0% to 25%, the laminar flame propagation speed of the fuel increases, the extinction strain rate rises, and the combustion limit expands. The laminar flame propagation speed of premixed methane/air gas reaches the maximum value when the equivalence ratio is 1.0, and the combustio... [more]
Analysis of Carbon Emission Reduction with Using Low-Carbon Demand Response: Case Study of North China Power Grid
Haoran Feng, Jie Ji, Chen Yang, Fuqiang Li, Yaowang Li, Lanchun Lyu
August 23, 2024 (v1)
Keywords: carbon emission factor, empirical analysis, low-carbon demand response, low-carbon optimization, the simulation of power system operation
The power sector is the single industry with the largest carbon emission in China, the carbon emission of which accounts for more than 40% of China’s total carbon emissions. In relevant research on the simulation of power system operation, current studies focus more on energy conservation and economical operation, while few consider the low-carbon optimization of the power system from the perspective of carbon emissions. In addition, in relevant research on carbon reduction in the power system, current studies focus more on controlling the direct carbon emission of the source side and less on the indirect carbon emissions of the load side, which focus on the reverse effect of a user’s electricity consumption behavior on the carbon reduction goals of the power system. This article delved into a deterministic simulation model of power system operation based on time series load curves and proposed a carbon reduction mechanism called the low-carbon demand response mechanism, which guides u... [more]
Study on the Conveying Characteristics of a Hanged Harvester Vibrating Screen for Ligusticum Chuanxiong
Jiarui Wang, Min Liao, Hailong Xia, Rui Chen, Junju Li, Yajun Yang
August 23, 2024 (v1)
Keywords: Chuanxiong harvester, conveying characteristics, kinematic analysis, vibrating screen
The problem of soil and Chuanxiong tuber congestion on vibrating screens usually exists during the Chuanxiong mechanized harvesting process. To address this problem, the conveyance performance of a crankshaft rocker vibrating screen was studied. By establishing and solving the dynamics and kinematics equations for the crankshaft rocker vibrating mechanism and Chuanxiong soil residue, the acceleration of the vibrating screen and Chuanxiong-soil residue was studied. The sliding speed, motion process, and conveying distance of the Chuanxiong soil residue were also analyzed. The theoretical analysis results indicated that the acceleration of the vibrating screen depends on the rod lengths of the vibrating mechanism and the crank rotational speed and position. The displacement of the Chuanxiong-soil residue along the positive sliding direction in a cycle was more significant than that of the negative sliding direction. The appropriate advancement speed of the harvester was also obtained. Th... [more]
Anti-Ice PMMA Surface Design and Processing
Yanming Chen, Aixin Feng
August 23, 2024 (v1)
Subject: Materials
Keywords: anti-ice, femtosecond laser, microstructure, PMMA, superhydrophobic
At low temperatures, PMMA surfaces are prone to ice and frost formation, which presents a significant challenge for PMMA’s efficient application in cold environments due to the difficulty in physically removing the accumulated ice. Superhydrophobic surfaces exhibit promising potential in passive anti-icing strategies. To exploit this advantage, we employed femtosecond laser technology to create six distinct microstructured PMMA surfaces, followed by surface modification using 1H,1H,2H,2H-perfluorodecyltriethoxysilane, resulting in enhanced hydrophobic and anti-icing properties. Among the tested structures, a secondary circular dot pattern achieved a remarkable contact angle of 153.7°, prolonging the freezing duration by approximately 40% at −10 °C, and reducing frost accumulation by over 50%. The ice adhesion strength was significantly reduced to 34 kPa. These findings contribute to broadening the applicability of PMMA and advancing the use of superhydrophobic surfaces in anti-icing ap... [more]
Improved Dujiangyan Irrigation System Optimization (IDISO): A Novel Metaheuristic Algorithm for Hydrochar Characteristics
Jingyuan Shi, Dapeng Zhang, Zifeng Sui, Jie Wu, Zifeng Zhang, Wenjie Hu, Zhanpeng Huo, Yongfu Wu
August 23, 2024 (v1)
Subject: Optimization
Keywords: hydrothermal carbonization, improved Dujiangyan irrigation system optimization (IDISO), meta-heuristic, single-task prediction, XGBoost
Hyperparameter tuning is crucial in the development of machine learning models. This study introduces the nonlinear shrinking factor and the Cauchy mutation mechanism to improve the Dujiangyan Irrigation System Optimization (DISO), proposing the improved Dujiangyan Irrigation System Optimization algorithm (IDISO) for hyperparameter tuning in machine learning. The optimization capabilities and convergence performance of IDISO were validated on 87 CEC2017 benchmark functions of varying dimensions and nine real-world engineering problems, demonstrating that it significantly outperforms DISO in terms of convergence speed and accuracy, and ranks first in overall performance among the seventeen advanced metaheuristic algorithms being compared. To construct a robust and generalizable prediction model for hydrochar element characteristics, this study utilized IDISO and DISO algorithms to fine-tune the parameters of the XGBoost model. The experimental results show that the IDISO-XGBoost model a... [more]
In Situ Combustion Characteristics of Heavy Oil in the Liaohe Oilfield at Different Temperatures
Yuning Gong, Yang Song, Tian Feng, Yong Guo, Xusheng Wang
August 23, 2024 (v1)
Keywords: combustion characteristics, fire-flooding, FT-ICR MS, GC–MS, in situ combustion
This study conducted in situ combustion oxidation experiments on crude oil from Block D within the Liaohe Oilfield, utilizing a kettle furnace low-pressure oxidation reaction method at various temperatures. The molecular composition of oxidation products was analyzed using gas chromatography−mass spectrometry (GC−MS) and high-resolution mass spectrometry. The results reveal that the molecular composition of the products remains relatively stable up to 300 °C, exhibiting a slight increase in C13-C30 alkanes. The ratio of the peak area for C21 to bisnorhopane is 0.082. From 300 °C to 450 °C, compounds with long alkyl chains gradually undergo thermal cracking, resulting in a significant increase in the production of alkanes within the C10−C30 range. The concentration of saturated hydrocarbons produced through thermal cracking reaches its maximum at a temperature of 400 °C. The most abundant peak of n-alkane is observed at C21, with a quantified ratio of peak area for C21 to bisnorhopane a... [more]
·OH Scavenger Optimized Grounding Electrode Atomization Corona Discharge Technology for Treatment of Coal Mine Acidic Wastewater
Chaofen Yang, Xiaofeng Ma, Lunqiu Zhang, Guang Lu, Dantong Geng, Yifan Zhang, Xiaolong You, Huan Liu, Yueyao Tian
August 23, 2024 (v1)
Subject: Environment
Keywords: ·OH scavenger, coal mine acid wastewater, COD value, grounding electrode atomization corona discharge
Coal mine acid drainage is a type of industrial wastewater generated in the process of coal production and utilization that has a low pH and contains a small amount of organic matter and SO42−, which is harmful to the environment. The ·OH scavenger was used to optimize the grounded electrode atomized corona discharge (GEACD) technology for the treatment of coal mine acidic wastewater. The effects of various factors on the discharge effect were investigated, and the optimal operating scheme for the subsequent test was determined as 35 mm distance between barrel electrodes, 0.6 mm diameter of wire electrodes, and a flow rate of 45 mL/min. The effects of discharge voltage, discharge time, and ·OH scavenger on COD removal rate and pH in coal mine acid drainage were also investigated. The results showed that at the optimum discharge voltage of 12 kV, discharge time of 66 min, and SO42− to ethanol concentration ratio of 1, the COD value decreased from 152.84 mg/L to 43.27 mg/L, and the pH va... [more]
Optimization Design of Deep-Coalbed Methane Deliquification in the Linxing Block, China
Bing Zhang, Wenbo Jiang, Haifeng Zhang, Yongsheng An
August 23, 2024 (v1)
Subject: Optimization
Keywords: deep-coalbed methane, deliquification, Linxing block, sucker rod pumping
The production of deep-coalbed methane (CBM) wells undergoes four stages sequentially: drainage depressurization, unstable gas production, stable gas production, and gas production decline. Upon entering the stable production stage, the recovery rate of deep CBM wells is constrained by bottom hole flowing pressure (BHFP). Reducing BHFP can further optimize CBM productivity, significantly increasing the production and recovery rate of CBM wells. This paper optimizes the deliquification process for deep CBM in the Linxing Block. By analyzing the production of deep CBM wells, an improved sucker rod pump deliquification process is proposed, and a method considering the flow in the tubing, annulus, and reservoir is established. Using the production data of Well GK-25D in the Linxing CBM field as an example, an optimized design of the improved rod pump deliquification process was undertaken, with design parameters including the depth of the sucker rod pump, the stroke length, and stroke rate... [more]
A Study on the Promoting Role of Renewable Hydrogen in the Transformation of Petroleum Refining Pathways
Xiaofei Shi, Gang Wang, Xiaolin Wang, Bo Chen
August 23, 2024 (v1)
Subject: Optimization
Keywords: carbon footprint, heavy fraction hydrogenation, linear programming, low-carbon oil refining, renewable hydrogen
The refining industry is shifting from decarbonization to hydrogenation for processing heavy fractions to reduce pollution and improve efficiency. However, the carbon footprint of hydrogen production presents significant environmental challenges. This study couples refinery linear programming models with life cycle assessment to evaluate, from a long-term perspective, the role of low-carbon hydrogen in promoting sustainable and profitable hydrogenation refining practices. Eight hydrogen-production pathways were examined, including those based on fossil fuels and renewable energy, providing hydrogen for three representative refineries adopting hydrogenation, decarbonization, and co-processing routes. Learning curves were used to predict future hydrogen cost trends. Currently, hydrogenation refineries using fossil fuels benefit from significant cost advantages in hydrogen production, demonstrating optimal economic performance. However, in the long term, with increasing carbon taxes, hydr... [more]
Study on Multi-Scale Cloud Growth Characteristics of Frustoconical Dispersal Devices
Weizhi Zhou, Qiang Li, Chunlan Jiang, Ye Du
August 23, 2024 (v1)
Keywords: cloud morphology control, frustum of cone, fuel dispersal, multi-scale coupling
This study aims to understand cloud growth behavior and enhance cloud safety and reliability by investigating the design of cloud dispersal devices. Based on the experimental results and simulation results, this study analyzes the dispersion characteristics of cloud materials within a frustoconical device with a semi-cone angle ranging from 0° to 10° across multiple scales. The collision aggregation model for cloud particles and the multi-scale coupling mechanism for cloud growth are established. The research shows that the semi-cone angle of the device extends the effective cloud growth duration and enlarges the cloud macroscopic size. At the mesoscopic scale, vortex phenomena are observed, causing particles to converge within the cloud, resulting in collisions and aggregation. The vortices enhance the continuity of the cloud concentration. The magnitude of these vortices demonstrates a positive correlation with the magnitude of the semi-cone angle of the dispersal device. For a macro... [more]
Scheduling of Automated Wet-Etch Stations with One Robot in Semiconductor Manufacturing via Constraint Answer Set Programming
Carmen L. García-Mata, Larysa Burtseva, Frank Werner
August 23, 2024 (v1)
Keywords: constraint answer set programming, knowledge representation and reasoning, Optimization, Scheduling, semiconductor manufacturing systems
Scheduling and optimization have a central place in the research area of computing because it is increasingly important to achieve fully automated production processes to adjust manufacturing systems to the requirements of Industry 4.0. In this paper, we demonstrate how an automated wet-etch scheduling problem for the semiconductor industry can be solved by constraint answer set programming (CASP) and its solver called clingcon. A successful solution to this problem is achieved, and we found that for all tested problems, CASP is faster and obtains smaller makespan values for seven of the eight problems tested than the solutions based on mixed integer linear programming and constraint paradigms. The considered scheduling problem includes a robot for lot transfers between baths. CASP is a hybrid approach in automated reasoning that combines different research areas such as answer set programming, constraint processing, and Satisfiability Modulo Theories. For a long time, exact methods su... [more]
Production of High-Power Nitrogen Sputtering Plasma for TiN Film Preparation
Taishin Sato, Sawato Igarashi, Katsuyuki Takahashi, Seiji Mukaigawa, Koichi Takaki
August 23, 2024 (v1)
Subject: Materials
Keywords: high-power pulsed plasma, HiPIMS, hollow-cathode, magnetic confinement, nitrogen, Penning discharge, sputtering, titanium target
High-density nitrogen plasma was produced using a high-power pulsed power modulator to sputter titanium targets for the preparation of titanium nitride film. The high-power pulsed sputtering discharge unit consisted of two targets facing each other with the same electrical potential. The titanium target plates were used as target materials with dimensions of 60 mm length, 20 mm height, and 5 mm thickness. The gap length was set to be 10 mm. The magnetic field was created with a permanent magnet array behind the targets. The magnetic field strength at the gap between the target plates was 70 mT. The electrons were trapped by the magnetic and electric fields to enhance the ionization in the gap. The nitrogen and argon gases were injected into the chamber with 4 Pa gas pressure. The applied voltage to the target plates had an amplitude from −600 V to −1000 V with 600 μs in pulse width. The target current was approximately 10 A with the consumed power of 13 kW. The discharge sustaining vol... [more]
Preparation of Bioaerogel from Iron-Rich Microalgae for the Removal of Water Pollutants
Xinqi Niu, Junhui Si, Binyi Chen, Qianting Wang, Sen Zeng, Zhixiang Cui
August 23, 2024 (v1)
Subject: Environment
Keywords: Adsorption, aerogel, microalgae, photo-Fenton, wastewater treatment
Microalgae-based materials have gained significant attention considering their rich resources, cost-effectiveness, and environmental friendliness. Herein, iron-rich microalgae (Chlorella pyrenoidosa, CP) were treated by hydrothermal reaction under alkaline conditions to remove the protoplast and obtain a hollow shell with an FexOy core inside. Then, the iron-rich microalgae-based aerogel (Fe-CP aerogel) was fabricated through a freeze-drying process. The as-prepared Fe-CP aerogel exhibited superior adsorption performance, and the maximum adsorption quantity for Cu2+ could reach 208.3 mg/g due to the synergistic adsorption of the hollow shell of CP cells and FexOy core. The Fe-CP aerogel also possessed super-hydrophilicity and displayed high separation efficiency (over 99%) when used for separating different oil/water emulsions. Moreover, the existence of FexOy endowed the Fe-CP aerogel with photo-Fenton activity, thus exhibiting excellent antifouling performance. The prepared Fe-CP aer... [more]
Oscillation Times in Water Hammer Signatures: New Insights for the Evaluation of Diversion Effectiveness in Field Cases
Bingxiao Liu, Wenhan Yue, Yajing Wang, Zhibin Gu, Ran Wen, Yang Qiu, Pukang Yi, Xiaodong Hu
August 23, 2024 (v1)
Keywords: diversion effectiveness, hydraulic fracturing, oscillation times, quefrency analysis, treating pressure analysis, water hammer diagnosis
Diversion is a crucial technique for effectively improving shale reservoir production by creating more complex fracture networks. Evaluating diversion effectiveness is necessary to optimize the parameters in hydraulic fracturing. Water hammer diagnostics, an emerging fracturing diagnosis technique, evaluate diversion effectiveness by analyzing water hammer signals. The water hammer attenuation, as indicated by the oscillation time, correlates with the complexity of fracture networks. However, it remains unclear whether the oscillation time is associated with diversion effectiveness. This paper elucidates the relationship between the water hammer oscillation time and diversion effectiveness by taking the probability of diversion and the treating pressure response as the evaluation criteria. Initially, a high-frequency pressure sensor was installed at the wellhead to sample the water hammer signals. Next, the oscillation times were determined using the feature extraction method. Simultan... [more]
Zero-Net Liquid Flow Simulation Experiment and Flow Law in Casing Annulus Gas-Venting Wells
Jifei Yu, Xiaoyou Du, Yanfeng Cao, Weitao Zhu, Guoqing Han, Qingxia Wu, Dingding Yang
August 23, 2024 (v1)
Keywords: annular experiments, holdup, pressure drop model, zero-net liquid flow
Under casing annulus gas venting, the annulus of the well is in a special state of zero-net liquid flow (ZNLF), leading to gas production without liquid at the wellhead, resulting in significant holdup issues. Therefore, conventional two-phase flow models cannot be used for calculation. To study the flow characteristics of ZNLF in the annulus of the well, this study established a visual experimental device with a total height of 5.4 m, an outer pipe inner diameter of 140 mm, and an inner pipe outer diameter of 72 mm. The flow characteristics of ZNLF were studied by controlling the casing pressure, initial liquid level, and bottom gas injection rate. The experimental results showed that the flow patterns of ZNLF are mainly bubbly flow and churn flow. Bubbly flow occurred at lower gas rates, while churn flow occurred at higher gas rates. In addition, the experiment found that when the gas injection rate and initial liquid column height were controlled to be the same, the liquid holdup de... [more]
Bioactive Compounds, Antioxidant Activity, and Antiproliferative Potential on Glioblastoma Cells of Selected Stone Fruit Juices
Drazen Raucher, Mandy Rowsey, James Hinson, Ina Ćorković, Mary Ann Lila, Josip Šimunović, Mirela Kopjar
August 23, 2024 (v1)
Keywords: anthocyanins, antiproliferative potential, blackthorn juice, cornelian cherry juice, iridoids, tart cherry juice
Glioblastoma presents one of the most formidable challenges in cancer treatment, remaining persistently incurable. There is a pressing need to explore less toxic alternatives, particularly natural remedies that could be applied in glioblastoma therapy. The aim of this research is to investigate the antiproliferative potential of selected stone fruit juices—tart cherry (Prunus cerasus), cornelian cherry (Cornus mas), and blackthorn (Prunus spinosa)—on U87-MG and GBM43 glioblastoma cells. Their effects were compared with temozolomide (TMZ), the current standard treatment. Additionally, the juices were assessed for their bioactive compounds and antioxidant potential. Unlike the other two juices, blackthorn juice did not exhibit an antiproliferative effect on U87-MG cells. However, all three juices, including blackthorn, demonstrated antiproliferative potential against TMZ-resistant GBM43 cells. Cornelian cherry exhibited an even stronger inhibitory effect than TMZ. This observation correl... [more]
Nuclear Magnetic Resonance Logging-Based Permeability Classification Modeling for Tight Sandstone Reservoirs
Zhongkui Liang, Xueying Li, Aiyan Sun, Fang Hou, Zhiwei Zhai, Qiang Sui
August 23, 2024 (v1)
Keywords: FZI, nuclear magnetic resonance, permeability, T2 geometric mean, tight sandstone reservoirs
The Upper Paleozoic tight sandstone reservoirs on the eastern margin of the Ordos Basin exhibit strong heterogeneity and complex pore structures, leading to poor correlation between porosity and permeability and insufficient accuracy in permeability calculations to meet the requirements of reservoir fine evaluation. Therefore, a new method for high-precision permeability calculation based on flow zone index (FZI) reservoir classification is proposed. This method determines the number of reservoir classifications based on the characteristics of the FZI normal probability distribution plot and establishes FZI division criteria for reservoir types. Classified reservoirs exhibit similar flow characteristics, significantly improving the correlation between permeability and porosity. Based on nuclear magnetic resonance (NMR) combined with mercury injection capillary pressure (MICP) experiments, a modeling method for calculating the flow zone index based on the geometric mean of NMR T2 is pro... [more]
Numerical Analyses of Perforation and Formation Damage of Sandstone Gas Reservoirs
Hao Liang, Zhihong Zhao, Haozeng Jin
August 23, 2024 (v1)
Keywords: formation damage, low permeability, perforation, sandstone gas reservoirs, shaped charge perforation
Shaped charge perforation is an important technology for sandstone gas reservoirs. In the process of shaped charge perforating, the initial permeability and porosity of the formation are greatly reduced, directly affecting oil and gas production. This paper uses smooth particle hydrodynamics (SPH) and finite element methods (FEMs) to study the formation damage caused by the shaped charge perforation. In this perforation simulation, the impact characteristics of the metal jet formed by the liner are coupled with the damage characteristics of the sandstone. A new mathematical model is proposed to describe the damage of permeability and porosity based on the Morris and Xue models. The simulated results show that a large-scale abdominal section appears at the perforation site, and the axis of the hole tilts with the increase in the perforation depth. The porosity damage at the perforation site is the greatest, up to 60%, while the permeability recovers to 90% of its initial state after pre... [more]
Full-Scale Demonstration of Nitrogen Removal from Mature Landfill Leachate Using a Two-Stage Partial Nitritation and Anammox Process
Rui Du, Dandan Lu, Zhiqiang Zuo, Renfu Zhang, Xi Lu, Chunshen Zhu, Zhetai Hu
August 23, 2024 (v1)
Subject: Optimization
Keywords: full-scale demonstration, mature landfill leachate, partial nitritation and anammox, seasonal temperature varying
The excessive discharge of nitrogen leads to water eutrophication. The partial nitritation and anammox (PN/A) process is a promising technology for biological nitrogen removal in wastewater treatment. However, applying it to mature landfill leachate (MLL) faces challenges, as the toxic substances (e.g., heavy metal) within MLL inhibit the activity of anammox bacteria. Therefore, most previous studies focused on diluted, pretreated, or chemically adjusted MLL. This study demonstrated at full scale that the two-stage PN/A process can treat raw MLL. Initially, the operational issue of sludge floatation resulted in rapid biomass loss with overflow discharging, which selectively suppresses nitrite-oxidizing bacteria (NOB), promoting the achievement of nitrite accumulation. After that, the NOB suppression was self-sustained by the high in situ free ammonia concentration, i.e., 26.2 ± 15.9 mg N/L. In the subsequent anammox tank, nitrogen removal primarily occurred via the anammox process, com... [more]
Microfluidic Insights into the Effects of Reservoir and Operational Parameters on Foamy Oil Flow Dynamics during Cyclic Solvent Injection: Reservoir-on-the-Chip Aided Experimental and Numerical Studies
Ali Cheperli, Farshid Torabi, Morteza Sabeti
August 23, 2024 (v1)
Keywords: cyclic solvent injection, foamy oil flow, microfluidic systems, solvent-based EOR
This study examines the microfluidic characterization of foamy oil flow dynamics in heterogeneous porous media. A total of 12 microfluidic CSI experiments were conducted using reservoir-on-the-chip platforms. In addition, detailed PVT analysis was performed to characterise the heavy oil/solvent systems. Moreover, a numerical model constructed with CMG software package (2021.10) has been validated against the experimental findings in this study. A clear-cut visualization study provided by microfluidic systems revealed that factors including solvent type, pressure depletion rate, and reservoir parameters have a significant impact on foamy oil flow extension. It was found that a solvent containing a higher CO2 content demonstrated more effective performance compared with other solvent compositions, owing to its capability to reduce viscosity, enhance swelling, and offer more gas molecules due to its superior solubility. Additionally, a high pressure-depletion rate amplifies the driving fo... [more]
Energy-Efficient Production of Microchloropsis salina Biomass with High CO2 Fixation Yield in Open Thin-Layer Cascade Photobioreactors
Ayşe Koruyucu, Torben Schädler, Amelie Gniffke, Konrad Mundt, Susann Krippendorf, Peter Urban, Karlis Blums, Billy Halim, Thomas Brück, Dirk Weuster-Botz
August 23, 2024 (v1)
Keywords: CO2 fixation, continuous production, dewatering, microalgae, open photobioreactor
Lipid production using microalgae is challenging for producing low-value-added products. Harnessing microalgae for their fast and efficient CO2 fixation capabilities may be more reasonable since algal biomass can be utilized as a precursor for various products in a biorefinery approach. This study aimed to optimize the productivity and efficiency of Microchloropsis salina biomass production in open thin-layer cascade (TLC) photobioreactors under physical simulation of suitable outdoor climate conditions, using an artificial seawater medium. Continuous operation proved to be the most suitable operating mode, allowing an average daily areal productivity of up to 27 g m−2 d−1 and CO2 fixation efficiency of up to 100%. Process transfer from 8 m2 to 50 m2 TLC photobioreactors was demonstrated, but with reduced daily areal productivity of 21 g m−2 d−1 and a reduced CO2 fixation efficiency, most probably due to increased temperatures at midday above 35 °C. An automated overnight switch-off of... [more]
Efficient Use of Secondary Raw Material from the Production of Polyamide Construction Products
Tomasz Olszewski, Danuta Matykiewicz, Mateusz Barczewski, Jacek Andrzejewski
August 23, 2024 (v1)
Subject: Materials
Keywords: mechanical properties, polyamide, post-production waste, recycling
This study aimed to assess the possibility of using post-production waste and the impact of the conditioning method on the mechanical and thermomechanical properties of polyamide injection molded parts. Samples containing 5, 10, and 15 wt.% of ground post-production waste were produced using injection molding technology. The rheological properties by oscillatory rheometry, the melt mass flow rate (MFR), and the thermal stability by thermogravimetric analysis (TGA) of polymer mixtures containing recycled fraction were determined. The samples were conditioned under the following conditions: 24 h and 14 days in distilled water, in a climatic chamber, and aged in a xenon-light-accelerated aging chamber. Then, the impact and static tensile strength and heat deflection temperature (HDT) were assessed. The results show that the addition of post-production waste in the form of grinding does not significantly affect the mechanical and thermomechanical properties of the finished products. This r... [more]
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