Separate Operations Research Articles

Study on the Process of Soil Clod Removal and Potato Damage in the Front Harvesting Device of Potato Combine Harvester

To improve soil clod removal and reduce potato damage in potato combine harvesters, this study investigates the processes involved in soil clod removal and potato collisions within the bar-lift chain separation device of the harvester. It outlines the structure and working principles of the machine, theoretically analyzes the key dimensions of the digging device and potato–soil separation components, and derives specific structural parameters. A dynamic mathematical model of the bar-lift chain is established, from which the dynamic equations are formulated. The analysis identifies factors that influence the dynamic characteristics of the bar-lift chain. This study examines the working principles and separation performance of the potato–soil separation device, with a focus on the collision characteristics between potatoes and both the screen surface and the bars. Key factors such as the separation screen’s line speed, the harvester’s forward speed, and the tilt angle of the separation screen are considered. Simulations are performed using a coupling method based on the Discrete Element Method (DEM) and Multi-Body Dynamics (MBD). Through simulation experiments, the optimal parameter combinations for the potato–soil separation device are determined. The optimal working parameters are identified as a separation screen line speed of 1.25 m/s, a forward speed of 0.83 m/s, and a tilt angle of 25°. Field harvesting experiments indicate a potato loss rate of 1.8%, a damage rate of 1.2%, an impurity rate of 1.9%, a skin breakage rate of 2.1%, and a yield of 0.15–0.21 ha/h. All results meet national and industry standards. The findings of this research provide valuable theoretical references for simulating potato–soil separation in combine harvesters and optimizing the parameters of these devices. Future potential research will consider the automatic regulation of the excavation volume of the potato–soil mixture, aiming to achieve intelligent control of the potato–soil separation operation.

Comparative efficacy of unilateral biportal endoscopic and full-endoscopic posterior cervical foraminotomy in the treatment of cervical spondylotic radiculopathy: a retrospective analysis.

The aim of this study was to compare the clinical efficacy of the full-endoscopic posterior cervical foraminotomy (FE-PCF) and the unilateral biportal endoscopic posterior cervical foraminotomy (UBE-PCF) in the treatment of cervical spondylotic radiculopathy (CSR). Patients who underwent posterior cervical spine surgery in our hospital from January 2020 to December 2022 were retrospectively analyzed. According to the surgical method, the patients were divided into two groups: FE-PCF group and UBE-PCF group. Perioperative data included operation time, Intraoperative blood loss and postoperative hospital stay were collected. The Visual Analog Scale (VAS)-arm, VAS-neck, and Neck Diability Index (NDI) was used to evaluate the clinical outcomes at preoperative, postoperative 1 week and Last follow-up. Serum creatine phosphokinase (CPK) and C-reactive protein (CRP) levels were recorded to evaluate surgical invasiveness. A total of 160 patients were included, including 89 cases of FE-PCF and 71 cases of UBE-PCF. The demographic and preoperative data showed no significant differences between the two groups (P > 0.05). The mean operating time was significantly shorter in the UBE-PCF group compared to FE-PCF group (P < 0.05). Serum CRP and CPK levels of the two groups both exhibited a pattern of rising and then falling, peaking one day following surgery and decreasing to near normal values three days after the operation. Compared with preoperative, both groups showed significant improvement in postoperative VAS and NDI scores, with a statistically significant difference (P < 0.05). However, the differences in results between the groups were not significant. Both UBE-PCF and FE-PCF are secure and efficient methods for treating CSR by continuous visualization. UBE-PCF offers predictable and adequate decompression within a reduced surgical duration, facilitated by its separate observation and operation channels.

DLCH-YOLO: An Object Detection Algorithm for Monitoring the Operation Status of Circuit Breakers in Power Scenarios

In the scenario of power system monitoring, detecting the operating status of circuit breakers is often inaccurate due to variable object scales and background interference. This paper introduces DLCH-YOLO, an object detection algorithm aimed at identifying the operating status of circuit breakers. Firstly, we propose a novel C2f_DLKA module based on Deformable Large Kernel Attention. This module adapts to objects of varying scales within a large receptive field, thereby more effectively extracting multi-scale features. Secondly, we propose a Semantic Screening Feature Pyramid Network designed to fuse multi-scale features. By filtering low-level semantic information, it effectively suppresses background interference to enhance localization accuracy. Finally, the feature extraction network incorporates Generalized-Sparse Convolution, which combines depth-wise separable convolution and channel mixing operations, reducing computational load. The DLCH-YOLO algorithm achieved a 91.8% mAP on our self-built power equipment dataset, representing a 4.7% improvement over the baseline network Yolov8. With its superior detection accuracy and real-time performance, DLCH-YOLO outperforms mainstream detection algorithms. This algorithm provides an efficient and viable solution for circuit breaker status detection.

Automated Optimization of a Multistep, Multiphase Continuous Flow Process for Pharmaceutical Synthesis.

Flow synthesis is becoming increasingly relevant as a sustainable and safe alternative to traditional batch processes, as reaction conditions that are not usually achievable in batch chemistry can be exploited (for example, higher temperatures and pressures). Telescoped continuous reactions have the potential to reduce waste by decreasing the number of separate unit operations (e.g., crystallization, filtration, washing, and drying), increase safety due to limiting operator interaction with potentially harmful materials that can be reacted in subsequent steps, minimize supply chain disruption, and reduce the need to store large inventories of intermediates as they can be synthesized on demand. Optimization of these flow processes leads to further efficiency when exploring new reactions, as with a higher yield comes higher purity, reduced waste, and a greener synthesis. This project explored a two-step process consisting of a three-phase heterogeneously catalyzed hydrogenation followed by a homogeneous amidation reaction. The steps were optimized individually and as a multistep telescoped process for yield using remote automated control via a Bayesian optimization algorithm and HPLC analysis to assess the performance of a reaction for a given set of experimental conditions. 2-MeTHF was selected as a green solvent throughout the process, and the heterogeneous step provided good atom economy due to the use of pure hydrogen gas as a reagent. This research highlights the benefits of using multistage automated optimization in the development of pharmaceutical syntheses. The combination of telescoping and optimization with automation allows for swift investigation of synthetic processes in a minimum number of experiments, leading to a reduction in the number of experiments performed and a large reduction in process mass intensity values.

A-021 Evaluation of a Novel N Terminal Pro B Type Natriuretic Peptide Assay as an aid in the Diagnosis of Acute Heart Failure in the Emergency Department

Abstract Background The signs and symptoms of acute heart failure (AHF) may overlap with other conditions and lead to diagnostic difficulty in the undifferentiated patient with dyspnea. The particularly high negative predictive value (NPV) of natriuretic peptides (NPs) in excluding AHF have rendered these assays especially useful in evaluating dyspnea in acute care setting. This study was conducted to assess the diagnostic performance of a novel N-terminal pro-B type natriuretic peptide (NT-proBNP) assay in the intended use patient population in the emergency department (ED). Methods A multicenter study was conducted in the U.S. on individuals presenting to the ED with dyspnea and a suspicion of AHF. Blood specimens were collected and tested using the Beckman Coulter Access NT-proBNP assay on the DxI 9000 Immunoassay Analyzer. Test results were compared to an adjudicated diagnosis clinical endpoint performed by an independent Clinical Events Committee blinded to the Access NT-proBNP result. Performance included NPV and sensitivity of an age-independent cut point of &amp;lt;300 ng/L to exclude AHF, and the positive predictive value (PPV) of the age-dependent cut points of &amp;gt;450, &amp;gt;900, and &amp;gt;1800 ng/L for ages &amp;lt;50 years, 50-75 years, and &amp;gt;75 years, respectively, for the diagnosis of AHF. The sample size required to achieve a 95% two tailed confidence interval (CI) was 150 subjects per age group to provide clinical performance at 90% (±10%) sensitivity. Sample size was based upon CLSI EP24-A2, Assessment of the Diagnostic Accuracy of Laboratory Tests Using Receiver Operating Characteristic Curves. Sensitivity and specificity were calculated at a series of cutoff points and plotted in separate receiver operation curves (ROC) for an overall age-independent rule-out analysis and for individual age-dependent groups separately. Area under the receiver operator characteristic curve (AUROC) was reported with 95% 2-sided CI. NPV and PPV with respective 95% 2-sided score CI was computed for the overall age-independent cut point and for each age group cohort. Results Of 490 enrolled patients, 41% were adjudicated with AHF with a median (Q1, Q3) age of 60 (47-76) years, and distributions of 46.1% female, 60.8% White and 38.2% Black. The assay had an AUROC for AHF of 0.88 (P&amp;lt;0.001), comparable to other commercially available NT-proBNP assays. The rule-out cut point of &amp;lt;300 ng/L had 96% sensitivity and NPV of 95%. Age-dependent cut points had sensitivity of 84%, 90%, and 87%, specificity of 81%, 70% and 61%, and PPV of 72%, 62%, and 74%, respectively. Conclusions The Access NT-proBNP assay demonstrated high clinical performance in the diagnosis and exclusion of acute HF in the undifferentiated dyspneic patient population and performed similarly well to validated assays used in current clinical practice. Given the continued increase in importance and reach of natriuretic peptide testing, these results are useful to extend availability of this assay to a larger audience.

Monitoring a batch crystallization process by acoustic emission

Crystallization is regarded as an important unit operation for separation and purification, as well as the production of solid particles with specified end-use properties. However, it is still difficult to control or to optimize the crystallization process due to the complexity of the coupled phenomena taking place simultaneously in the liquid and solid phases. In order to overcome such drawback, different analytical technologies have been implemented in the literature for monitoring (in situ, at best) the key crystallization parameters, e.g. solute concentration and crystal size distribution, which in turn enhances the comprehension about this operation. In our work, a multi-probe monitoring system composed of acoustic emission, ATR-FTIR and imaging probes was applied to the crystallization of a model system (an aqueous solution of adipic acid) in a semi-batch crystallizer. The crystallization was carried out under two different feed rates and under vacuum or atmospheric pressure. The goal was to demonstrate the usefulness of the multi-probe system for monitoring the crystallization process and to study the influence of the process (stirring rotation speed, cooling speed, etc.) on the acoustic emission. As a matter of fact, the multi-probe system tracked information about the dissolved adipic acid in the liquid phase with the ATR-FTIR spectrometry, while the crystal size, shape and number were monitored with the help of the imaging probe (with image treatment methods). The acoustic emission probes were used to detect the beginning of crystallization and the phenomena of crystal growth and agglomeration

Growth of broken crystals tracked in 4D using X-ray computed tomography and its influence on impurity incorporation

Crystallization is a commonly used unit operation for separation and purification. During processing, crystals may break due to mechanical stress, e.g., intentionally by milling or unintentionally through collision with stirrers. This study investigates the growth of broken crystals in three dimensions using X-ray micro-computed tomography. The results show that damaged regions of crystals grow faster than faceted regions, and crystals become faceted through growth. Initially, this happens on a microscale, producing faceted but concave regions on the crystal surface. Eventually, crystals become convex. Shape-healing through growth incorporates inclusions in the crystals. These findings have important implications for designing and optimizing crystallization processes in the pharmaceutical, food, and chemical industries, as purity is often a critical quality criterion adversely affected by inclusions. In addition, the kinetics in crystallization processes are likely to be strongly affected by the growth of non-faceted and concave crystals.

Signal Separation Operator Based on Wavelet Transform for Non-Stationary Signal Decomposition.

This paper develops a new frame for non-stationary signal separation, which is a combination of wavelet transform, clustering strategy and local maximum approximation. We provide a rigorous mathematical theoretical analysis and prove that the proposed algorithm can estimate instantaneous frequencies and sub-signal modes from a blind source signal. The error bounds for instantaneous frequency estimation and sub-signal recovery are provided. Numerical experiments on synthetic and real data demonstrate the effectiveness and efficiency of the proposed algorithm. Our method based on wavelet transform can be extended to other time-frequency transforms, which provides a new perspective of time-frequency analysis tools in solving the non-stationary signal separation problem.

Automated robotic systems in surgical practice

The use of robotic systems has long gone beyond experimental medicine. More than 200 thousand operations per year are carried out with the use of just the most popular robotic complex Da Vinci. Further development of robotics will contribute to improvement of quality and accuracy of surgical interventions. Even now, it enables reduction of postoperative complications to almost zero. This review presents the analysis of the results of introducing robots into surgery. An overview of the data presented in PubMed, Cochrane Library, Science Direct and eLIBRARY was performed.

SEARCH FOR METHODS TO INCREASE THE SEDIMENTATION RATE OF THE UPPER FLOATING LAYER OF OIL SLUDGE PITS

Traditionally, oil sludge with a liquid-viscous consistency is separated into petroleum product, water and solid mechanical impurities. A large number of technological devices, including separators, centrifuges, hydrocyclones of various designs, have been developed to carry out the operation of interfacial separation of liquid-viscous oil sludge.On the territory of every oil refinery that has been in operation for decades, there are oil sludge ponds — natural settling ponds in which large quantities of oil waste accumulate.The problem of processing barn oil sludge in the oil production and refining industry has not yet been completely solved. This is due to the high stability of barn emulsions, the peculiarities of their composition and properties, which are constantly changing under the influence of temperature and various processes occurring in them.The article presents the results of research aimed at identifying the possibility of destruction of a persistent oil-water emulsion taken from the upper floating layer of an oil sludge pit and its preparation without changing the technological scheme and technological parameters.The results of laboratory studies on the destruction of oily liquid during static sedimentation are considered. Simulation of the oily liquid preparation process was carried out in compliance with the temperature and time conditions of operation, with the use of demulsifiers, by analogy with the process of oily liquid preparation, as at the unit. The results of the simulation showed that at the dosage of the demulsifiers used at the unit, even with an increase in the dosage and an increase in the settling time to 5 days, the oil-water emulsion did not collapse at 60 0C. Further studies were carried out by testing eight brands of demulsifiers at different dosages and elevated temperatures. Based on the results of the research and the conclusions made, a scheme for the preparation of oil-containing liquid at static sludge with the existing set of equipment at the unit is proposed.Further studies were carried out to increase the depth and sedimentation rate of the persistent oil-water emulsion.

The qP- and qSV-wave separation in 2D vertically transversely isotropic media and their applications in elastic reverse time migration

Compressional and shear wave separation is an important step in anisotropic elastic reverse time migration (ERTM). With separated wavefields, we can generate images between different wave types and reveal more subsurface physical properties, as well as remove unwanted crosstalk and improve image quality. Traditional Helmholtz decomposition based on divergence and curl operations for isotropic media cannot be directly extended to vertically transversely isotropic (VTI) media. Wave-mode separation methods, similar to the nonstationary spatial filter and Poynting vector, cannot preserve the phase and amplitude information of the original coupled wavefield, thus limiting their application in ERTM. Currently, the anisotropic wavefield decomposition methods include the wavenumber-domain approach, the low-rank approximation, and other separation approaches based on different approximations, e.g., weak or elliptical anisotropy. These methods are either computationally intensive or involve large separation errors, especially in models with strong heterogeneities and anisotropy. The VTI wavefield separation operator is essentially defined in a mixed space-wavenumber domain. We introduce scalar operators to transfer operations from this mixed space-wavenumber domain to the space domain. The local wave propagation direction in the scalar operators is estimated using the Poynting vector, which is highly computationally efficient in the space domain. When we apply the wave separation method to ERTM, we not only obtain the vectorized qP and qSV waves but also retrieve the scalar qP wavefield. The scalar and vector wavefields preserve the amplitude and phase information in the original coupled wavefield. For anisotropic ERTM, we suggest using the scalar imaging condition to generate the PP image and the magnitude- and sign-based vector imaging condition to produce the PS image, both having higher image accuracy than the dot-product imaging condition. Numerical examples are used to validate our anisotropic wavefield separation method and the related ERTM workflow.

Enumeration and Representation Theory of Spin Space Groups

Fundamental physical properties, such as phase transitions, electronic structures, and spin excitations, in all magnetic ordered materials, were ultimately believed to rely on the symmetry theory of magnetic space groups. Recently, it has come to light that a more comprehensive group, known as the spin space group (SSG), which combines separate spin and spatial operations, is necessary to fully characterize the geometry and underlying properties of magnetic ordered materials. However, the basic theory of SSG has seldom been developed. In this work, we present a systematic study of the enumeration and the representation theory of the SSG. Starting from the 230 crystallographic space groups and finite translation groups with a maximum order of eight, we establish an extensive collection of over 100 000 SSGs under a four-index nomenclature as well as international notation. We then identify inequivalent SSGs specifically applicable to collinear, coplanar, and noncoplanar magnetic configurations. To facilitate the identification of the SSG, we develop an online program that can determine the SSG symmetries of any magnetic ordered crystal. Moreover, we derive the irreducible corepresentations of the little group in momentum space within the SSG framework. Finally, we illustrate the SSG symmetries and physical effects beyond the framework of magnetic space groups through several representative material examples, including a candidate altermagnet RuO2, spiral spin polarization in the coplanar antiferromagnet CeAuAl3, and geometric Hall effect in the noncoplanar antiferromagnet CoNb3S6. Our work advances the field of group theory in describing magnetic ordered materials, opening up avenues for deeper comprehension and further exploration of emergent phenomena in magnetic materials. Published by the American Physical Society 2024

Modelling long-term operational dynamics of grid-connected hydro- photovoltaic hybrid systems

The development of variable renewable energy sources (VRESs), such as wind and solar photovoltaic (PV), has become a strategic choice for ensuring the security of electricity supplies and the decarbonization of power systems. The hybridization of hydropower with VRESs is an important measure for guaranteeing the smooth and cost-effective integration of VRESs into the power system. However, the highly variable weather- and climate-driven spatial and temporal fluctuations in VRES performance have significant potential to affect the optimal trajectory of hydropower operations. Therefore, it is essential to understand how hydropower responds to VRESs over long-term horizons, thereby allowing informed operation decisions to be made for hybrid generation systems (HGSs). In this study, a long- and short-term nested operation model is developed for hydropower operations considering PV integration. Specifically, the long-term model determines the day-by-day hydropower production over many years, and the short-term model simulates the day-ahead generation scheduling and real-time operation processes of the HGS. Performance metrics are established for evaluating the complementary operation in comparison with separate operation of hydropower and PV plants. China's two representative hydro-PV HGSs (Zhongyu and Longyangxia) are selected as case studies. The results indicate that the hybrid generation of hydropower and PV could, on average, increase total electricity generation by 11.33 %, reduce the load loss rate by 9.31 %, and decrease the PV curtailment rate by 36.60 %. However, hydro-PV hybridization may lead to an increase of 9.22 % in the water spillage rate and a decrease of 0.094 kWh/m3 in the water–electricity conversion coefficient. Therefore, hybrid generation of hydropower and PV could further enhance energy yield and supply reliability. Also, the importance of improving hydropower flexibility is highlighted.

Fabricating Polymeric Micelles with Enrichment and Cavity Effect for In Situ Enzyme Imobilization from Natural Biosystems.

Metal-organic frameworks and hydrogen-organic frameworks (MOFs and HOFs) are attractive hosts for enzyme immobilization, but they are limited to immobilizing the purified enzymes, making industrial upscaling unattractive. Herein, aptamer-modified dual thermoresponsive polymeric micelles with switchable self-assembly and core-shell structure are constructed, which enable selective immobilization of trypsin directly from complex biological systems through a cascade operation of separation and immobilization. Their steric self-assembly provides a large amount of adsorption sites on the soluble micellar shell, resulting in high adsorption capacity and excellent selectivity. Meanwhile, their aptamer affinity ligand and cavity maintain the native conformations of trypsin and offer protective effects even in harsh conditions. The maximum adsorption capacity of the polymeric micelles for trypsin was determined to be 197 mg/g at 60 min, superior to those of MOFs and HOFs. 67.2 and 86.6% of its original activity was retained for trypsin immobilized in the cavity under strong alkaline and acidic conditions, respectively.

Anti-dissolving cellulose-based separator for dendrite-free rechargeable aluminum batteries

Rechargeable aluminum batteries (RABs) are noteworthy due to their environmental sustainability and cost-effectiveness. However, its practical applications suffer from wilder growth of anode dendrites and greater physicochemical instability of separator triggered by corrosive ionic liquid electrolytes (ILs). This work produces a core-shell structured CCP@TiO2 separator by introducing TiO2 nanolayer onto commercial cellulose paper (CCP) to improve its stability by tackling the challenge of cellulose dissolution in ILs. By combining experimental and simulation studies, CCP@TiO2 separator exhibits excellent anti-dissolving property and interfacial polarization effect, not only provides the stable anion flux and high anion transfer number of 0.29, but also facilitates the uniform distribution of the ions and electric charges at the separator/electrolyte/anode interface, thereby promoting dendrite-free Al deposition. Thus, the assembled graphite//Al battery maintains a higher discharge capacity of 90.3 mAh g−1 after 1000 cycles at 0.2 A g−1, compared to the 82.4 mAh g−1 residual of that with glass fiber (GF) separator. Furthermore, the battery with secondary use CCP@TiO2 separator still maintains 98 % capacity retention. Such separator engineering of insolubility of cellulose in ILs and inhibition of dendrite growth, provides an unparalleled pathway for promising alternative to GF separator and stable operation, sustainable development of RABs.

Synthesis of Chromone‐3‐phosphonates via Arbuzov‐Type C−P Cross Coupling from o‐Hydroxyphenyl Enaminones and Phosphites

AbstractWith an in situ C−H iodination tactic, a method for the synthesis of chromone‐3‐phosphonates was developed with trialkyl/triaryl phosphites as the reaction partners of o‐hydroxyphenyl enaminones by palladium catalysis. The product formation consists of cascade C−H iodination, chromone annulation, and Arbuzov‐type C−P cross coupling as major transformations. In addition to providing an enaminone‐based synthetic method to chromone‐3‐phosphonates, the work shows the advantage of step economy by skipping the separate operation for preparing the iodo‐functionalized chromone intermediate.

تقييم إمكانية االعتماد على نظام السالمة اآللي و صمامات اآلمان لخزانات فصل الزيت الخام في حقل نفط

A crude oil separator is a pressure vessel used to separate oil and gas in an oil well stream. The separators are provided with a Basic Process Control System (BPCS) and a protection system which consists of a Safety Instrumented System (SIS) and a Pressure Relief System (PRS). Failure of the crude oil separator might result in fire, explosion, and toxic dispersions. The world has witnessed several fire and explosion incidents due to the operation of crude oil separators. Reliability of the control and protective systems of crude oil separators is very important to verify their abilities to perform their functions. This technical article presents an overview of the layers of protection of crude oil separator and the reliability of protective systems. The article also presents an evaluation of the reliability of SIS and safety valves of crude oil separators in an oil field. The crude oil separators are arranged in the form of three parallel trains of separators each train divided into three stages. The first stage consists of two separators and each stage of the second and third stages consists of one separator. The reliability of the different configurations of the SIS and safety valves of a train of production separators has been estimated and found to be acceptable.

Dampak Pemeliharaan Serta Pengoperasian Oily Water Separator Dalam Upaya Mencegah Pencemaran Laut Oleh Minyak Dari Kapal

Impact of Maintenance and Operation of Oily Water Separators in Efforts to Prevent Marine Pollution by Oil from Ships. Environmental cleanliness is curr­­­ently being given special attention by both developed and developing countries, and therefore has resulted in many regulations to maintain the balance of the ecosystem of life in this world. This imbalance can cause damage to the ecosystem due to pollution, one of which occurs in the ocean. This pollution is caused, among other things, by oil spills, toxic liquids, dangerous substances carried by sea in the form of packaging, rubbish from ships and air pollution. The aim of this research is to find out the pressure or procedures for operating the Oily Water Separator (OWS) aircraft correctly and according to procedures, as well as to find out how to maintain and repair the Oily Water Separator (OWS) aircraft, and why oily water planned operations may not occur. Separator (OWS). The method used in research is descriptive method. The data in this research were obtained from observations on the ship, documents obtained when conducting research on the ship, and from interviews. From the results of this research, data was obtained that against the background of the impact of maintenance and operation of the Oily Water Separator (OWS) in an effort to prevent marine pollution by oil from ships, it was stated that problems were discovered when carrying out research on the Oil Water Separator itself. The lack of air pressure would disrupt its operation. a three-way valve, as a whole, will disrupt the working system of the Oily Water Separator (OWS) water and oil separator. If the Oil Level Sensor which detects oil is found to be not working properly, it must be replaced with spare parts available on the ship. Apart from that, there is no regular operation of the Oil Water Separator, because problems arise on an aircraft because the operator does not carry out standard operating procedures. . To support work programs that comply with regulations, in this case it is necessary to standardize fundamentally and thoroughly regarding the implementation of standard operating procedures and be guided by the company's manual instruction book or PMS.

Film investigation of swirl-vane separator based on Euler grid approximation and coupled film method of Eulerian wall film and volume of fraction method

The movement of multiple liquid droplets within steam flow constitutes a commonplace and noteworthy phenomenon across a spectrum of disciplines, including environmental science, chemical engineering, and energy studies. To simulate the dynamic behavior of these droplets, the methodology of Euler grid approximation, along with the Eulerian wall film (EWF) coupled with the volume-of-fluid (VOF) method, was successfully employed to simulate the steam-liquid separation and liquid film processes within the swirl-vane separator. The trajectory of droplets within the gas phase field was constructed using the Euler grid approximation methodology, while the flow of liquid film formed by droplet–wall collision was modeled based on the coupled EWF and VOF liquid film model. The investigation of two-phase flow and liquid film flow within the swirl-vane separator under high temperature and pressure conditions was conducted utilizing the proposed model, with subsequent analysis of the pertinent characteristics of droplets and liquid film. Specifically, the thickness and velocity of the liquid film significantly increased with the increase in droplet mass flow rate, with larger droplets more prone to concentrate and form stable flow of thick liquid film. The study results may hold significant implications for the design, operation, and optimization of separators.

Development of water vapor recovery membrane for efficient recycling system

Abstract In wastewater treatment at semiconductor plants separation operations are currently conducted mainly by distillation. Membrane distillation using ceramic surface-treated membranes is expected to provide more efficient separation. In this study, we investigated the improvement of acid resistance of surface-treated ceramic membranes by using four silicon alkoxides, Hexamethyldisiloxane(HMDS), Dimethyldimethoxysilane(DMDMOS), 3,3,3-Trifluoropropyltrimethoxysilane (TFPrTMOS), Tetramethoxysilane(TMOS) were used as surface treatment and it was performed in the gas phase. The water vapor permeance of the TFPrTMOS surface treated membrane was 2.35✕10−6 [mol m−2 s−1 Pa−1], and it maintained its functionality after immersion in a 10 wt% sulfuric acid solution under 60°C for 170 h. The membrane with multiple surface treatments with TFPrTMOS showed an increase in acid resistance to 491h, indicating that unreacted alkoxide affected the degradation. The water vapor permeance of the TFPrTMOS-DMDMOS treated membrane combined silicon alkoxides was 2.85✕10−6[mol m−2 s−1 Pa−1] and the acid resistance was 687 h. It is possible that DMDMOS acted as a cross-linker in modifying the unreacted alkoxide portion of the membrane, leading to improved resistance.