Process Flow Research Articles

Beyond diagnosis: using a futurist approach to improve access to radiation oncology services in South Africa

Aim Radiation oncology is an integral aspect of comprehensive cancer treatment, with approximately 50% of patients requiring curative or palliative radiotherapy intervention. In the South African public sector, radiation oncology services are constrained by various factors including service coverage, equipment and staff shortages, causing consequent delays in access to care. The National Cancer Strategic Framework for South Africa (NCSF) (2017-2022) offers strategic direction for cancer services in the country. Methods Futurist causal layered analysis (CLA) provides a comprehensive approach to exploring the multifaceted factors that influence access to radiation oncology services. Using the established layers of CLA, namely, the litany, systemic, worldview and mythical layers, the NCSF, relevant literature, and expert perspectives, were used to explore the multiple levels of influence related to radiation oncology services in South Africa. Findings Considering litany, review of process flows and radiation oncology care models could offer strategic pathways for reducing waiting times and improving access to care. From the systemic layer analysis, health system strengthening should include improving clinical governance and access to available services within both the public and private sectors. This could simultaneously address the worldview of an unconstitutional lack of access to radiation oncology care within the public health sector. The final level considered myths related to radiation oncology in South Africa, including its perceived efficacy only in advanced cancer stages, and highlighted the importance of a business case for radiation oncology services to support enhanced planning and outcomes. Conclusions CLA methodology offers new insights into the challenges and opportunities facing radiation oncology services in South Africa. By comprehensively addressing the complex causal layers impacting radiation oncology services, policymakers and stakeholders can make more informed decisions to improve access to radiation oncology care in the country. The study recommends that the entire cascade of cancer care, including treatment pathways and multi-stakeholder perspectives, should be reviewed. Internal and external factors that delay the initiation of radiotherapy should be mapped and mitigated.

Investigating stingray skin as a novel material for high-performance textile items

ish skin leather is a sustainable alternative to traditional leather production. The goal of this study is to create a recipe for turning raw stingray leather into protective gloves for hands. The process flow of Stingray Leather Processing and optimization of each single step has been done. The technique is based on tanning agents, formulating new processing methods, conducting an extensive market analysis, and examining the environmental impact. The processed stingray leather was evaluated for resistance to abrasion, cur, and puncture resistance, and it was found that the stingray skin gloves showed better cut and abrasion resistance than the conventional gloves available in the market.

Improving influenza vaccination assessment and uptake, one step at a time in a cancer center.

280 Background: Influenza immunization has shown to decrease morbidity and mortality of influenza infections. From September to December 2022, at the infectious diseases (ID) clinic at our institution, 73% of the patients did not undergo influenza immunization assessment during their clinical encounters and only 3% of the patients had the influenza vaccine administered. Furthermore, documentation of vaccine discussion was done in 73% of cases. Our aim was to improve vaccination assessment from 73% noncompliant to 50%. Methods: A multidisciplinary team of nurses, nurse leaders, pharmacists, and quality specialists was assembled to analyze baseline data on influenza vaccination assessment, administration, and documentation at the ID clinic from Sept to Dec 2022 using The Model for Improvement. Quality tools were utilized including Cause and Effect Diagram, Current State Process Flow Chart and Prioritization Matrix, to identify and prioritize opportunities for improvement creating a worklist for improvement focus. Vaccine assessment measured via EPIC immunization tab marked as reviewed, discrete areas to document vaccination and their administration were not a part of nursing or provider’s workflow. Using the Plan, Do, Study, Act (PDSA) method, the following changes were tested: PDSA Cycle 1; A green sticker highlighted those patients needing vaccine assessment. PDSA Cycle 2; A smart phrase was created for documentation in nurses’ notes and PDSA Cycle 3; provider’s notes regarding vaccine recommendations. Results: Interventions were associated with an improvement of influenza assessment via the immunization tab marked as reviewed in the ID outpatient clinic from 73% noncompliance to 3% noncompliance from September 2023 to March 2024. Concurrent with improvement of our assessment process, our on-site vaccination rate increased from 97% error to 89% error (Table) and there was 50% improvement in provider’s documentation. Conclusions: The formation of a multidisciplinary working group and implementation of quality tools interventions resulted in timely significant improvement in vaccination assessment, documentation, and administration. Subsequently, we were granted institutional approval to add an EPIC clinical decision support tool to standardize influenza vaccination documentation. Future strategies include implementation and evaluation of the utilization of Health Maintenance tool in the ID clinic before expansion to other clinics in our institution. Influenza vaccine administration vs outpatient visits in the ID clinic. Month/Year # Outpatient visits # Vaccines administered in clinic % of vaccines administered Influenza Sep-Dec 2022 1827* 54 2.95% Influenza Sept 2023-March 2024 2682 251 9.36% *Includes video and telephone visits.

Determination of ecological flow based on probability distributions of annual and monthly flows

ABSTRACT Developing scientifically sound ecological flow is crucial for protecting river ecosystems. However, most of the existing hydrological methods for determining ecological flow make it difficult to consider both inter-annual and intra-annual changes in runoff. To compensate for this shortcoming, this paper proposes an innovative ecological flow determination method based on the probability distributions of annual and monthly flows. Marginal distributions of annual and monthly flows are first fitted, and the Copula function is used to create joint probability distributions of annual and monthly flows. Conditional probabilities for different monthly flow sizes under different annual flow conditions are then calculated based on Bayesian inference. The conditional probabilities are combined with the flow–duration curve-–based method to finalize the ecological flow process considering both intra- and inter-annual runoff changes. A case study was conducted in Jinsha River, China. The results show that the total annual ecological water demand of the Jinsha River is 1.50, 1.25, and 1.04 × 1011 m3 under annual flow scenarios of high, medium, and low flows, respectively, which provide a red line for the development of water resources and hydro-energy resources of the Jinsha River, as well as for the better protection of the natural plant and animal species.

The mechanism of proppant transport dynamic propagation in rough fracture for supercritical CO2 fracturing

Supercritical CO2 fracturing technology has shown great potential for enhancing production in unconventional reservoirs. It is essential to clarify the transport mechanism of proppant under the dynamic propagation conditions within rough fractures. A realistic rough fracture model is reconstructed, and Computational Fluid Dynamics simulations are conducted to track proppant movement during fracture propagation. The typical transport characteristics of proppant within rough fractures are revealed, and the effects of fracture propagation rate, proppant density, mass flow rate, particle size, sand ratio, and temperature on the support effect are discussed. The results show that the flow channels formed by sand carrying fluid in rough fractures are complex, with fracture propagation changing some flow channels. The proppant forms an irregular sand bed interspersed with unfilled areas, and complex flow characteristics are generated. The increase in fractal dimension increases the resistance in the fluid flow process and affects the movement of the proppant, which tends to create unfilled areas. Low density and size of proppant can improve the proppant placement length. In a certain temperature range, high temperature injection of sand carrying fluid can improve the proppant placement effect. In addition, the low sand ratio and high mass flow rate pumping can be used to form the dominant channel, followed by pumping with a high sand ratio and low mass flow rate for effective support.

Investigation into the Energy Loss Mechanism of Pump Turbine During the Runaway Process Based on Entropy Production Theory

Abstract The power-trip of the pump under certain conditions leads to the runaway of the unit, causing dangerous transitional process in pumped storage power stations. This process is characterized by transient hydraulic features like flow separation and vortex structures, which increase hydraulic losses significantly and severely impact unit efficiency and stability. This paper aims to elucidate the mechanism of energy loss due to unstable flow during pump turbine runaway. It focuses on a high-head model pump turbine, examining the transient flow process from pump conditions to runaway conditions. It conducts quantitative analysis of energy loss using entropy production theory, besides, further clarifies the location and causes of hydraulic losses by integrating with internal flow analysis. The results show that a significant high-entropy production zone is captured in the pump braking condition, indicating extremely chaotic internal flow in this area during the runaway transition process. Additionally, throughout the transition process, turbulent entropy production initially increases, then decreases. Turbulent entropy production accounts for more than 80% of total entropy production, indicating that turbulent entropy production dominates throughout the entire transition process. The energy of the water is primarily dissipated within the runner during the runaway process. The maximum proportion is 87%, which is in the pump braking condition. Correlation analysis between flow and hydraulic losses reveals that vortex structure induced by flow separation under off-design conditions is the primary contributor to increased hydraulic losses.

A Continuous Flow Process for the Defluorosilylation of HFC-23 and HFO-1234yf.

A continuous flow process has been developed for the defluorosilylation of trifluoromethane (HFC-23) and 2,3,3,3-tetrafluoropropene (HFO-1234yf) through reaction with lithium silanide reagents under inert conditions. Design of experiment optimization improved process conditions, including productivity, yields, reduction of solvent use, and gas destruction. The small chain fluorinated organosilane products R3SiCF2H and R3SiCH2C(F)═CF2 were competent nucleophiles in the fluoride-catalyzed difluoromethylation of aldehydes, and trifluoroallylation of aldehydes, ketones, and imines.

Image‐based quality control of fresh concrete based on semantic segmentation algorithms

AbstractIn practice, various empirical methods such as the flow table test or the slump test are in use worldwide for assessing the workability of fresh concrete on the construction site. The majority of these tests has in common, that fresh concrete is subjected to some kind of defined flow process on a standardized table‐like platform and that the geometrical properties of the material after the flow has ceased is determined by simple means such as measuring the flow cake diameter or its sag. The paper at hand proposes a novel image‐based approach for an automatic derivation of concrete properties as part of the flow table test. The image‐based method enables a digital evaluation of concrete properties. By combining digital image analysis and deep learning methods, not only the consistency but also an abundance of additional concrete properties can be derived from image data. In this way, the quality control of the fresh concrete can be expanded to include a large number of additional parameters, currently not available to the producer nor to the construction site. This data can be integrated into a digital control loop, with which communication between the concrete producer and the construction site can be automated using highly precise real‐time data.

Enhanced denitrification by sunlight–hematite: A neglected nitrogen flow pattern in red soil

Mineral-microbe interactions in the Earth's Critical Zone significantly influence elemental biogeochemical cycling and energy flow processes. This study addresses the key scientific question of how semiconducting minerals drive microbial nitrogen cycling. In the red soil environment, the presence of semiconducting minerals enhances the denitrification process mediated by facultative microorganisms (Pseudomonas aeruginosa PAO1) with denitrifying activity. Compared to darkness, light significantly enhanced the synergistic denitrification kinetic process of red soil and Pseudomonas aeruginosa PAO1 (1.87 times). Cyclic voltammetry shows that the P. aeruginosa PAO1-red soil synergistic system exhibits distinct redox peaks under light. The constant potential current curve and electrochemical impedance spectroscopy measurements reveal a high photocurrent density (1.0 μA/cm2) and minimal polarization resistance (102 Ω) under this condition. These findings confirm that the sunlight-red soil-P. aeruginosa PAO1 synergistic process has excellent electron generation and migration capacity, active redox reactions, and good electron compatibility. Additionally, the photoelectrons of semiconductive minerals in red soil profoundly impact the metabolic processes of microbial denitrification functional genes. Using real-time polymerase chain reaction (qPCR) gene array technology, the abundance of nitrogen metabolism functional genes in P. aeruginosa PAO1 increased by 200 % during the light-red soil synergistic process. Notably, denitrification-related genes (ureC, nirS1, gdhA, and nosZ2) were significantly upregulated. This study confirms that semiconducting minerals are involved in the nitrogen cycle pathway of microbial denitrification and supplements the theory of mineral-microbial synergistic element biogeochemical cycling in the natural environment.

Low-voltage operatable top-gated organic transistors based on the solution-processed binary polymers dielectric for simplifying the manufacturing flow of arrayed AMOLED

The complex process flow is an important factor that hinders the development of active-matrix organic light-emitting diode (AMOLED) displays. Organic thin-film transistors (OTFTs) are one of the promising candidates as the pixel circuits for AMOLEDs. Both the architecture and the fabrication of OTFTs are crucial elements to determine the process flow and cost of the AMOLEDs. In this Letter, we develop a strategy to significantly simplify the process flow and reduce the cost of AMOLEDs by constructing top-gated OTFTs with a solution-processed vertically phase separated binary polymer dielectric as the pixel circuits. The design on the OTFTs considers both the process flow and the device performance in terms of mobility and operating voltages. The mechanism to improve device performances is discussed. Finally, a 3 × 4 arrayed AMOLED is demonstrated, in which a high mobility over 0.3 cm2/Vs is obtained on the switching and driving OTFTs, and luminance over 300 cd/m2 is achieved on the OLEDs at the supplied low operating voltages of 10 V. This strategy provides a competitive technological route for the manufacturing of AMOLEDs.

Geometrical characterization of fracture systems using point clouds and SELF-Software: example of the Añisclo anticline carbonate platform, Central Pyrenees

Natural fracture systems contribute significantly to rock mass anisotropies. Characterizing these systems is essential for understanding processes of fluid flow, energy exploration and storage, slope stability or tectonic processes that can affect the permeability or compaction of the material, as well as reflect its temporal evolution. This work presents a set of automatic and supervised algorithms integrated into the open-access software solution SEFL, designed to characterize fracture systems using remote sensing data sets. The software implements various strategies to quantify geometrical parameters with deterministic or stochastic descriptions, facilitating a detailed characterization of the fracture system for numerical simulations. Geological outcrops provide direct access to the rock masses and discontinuities, offering analogies with materials that are otherwise inaccessible for its direct study. The digital acquisition of the terrain using high-resolution techniques, such as Terrestrial Laser Scanner (TLS) or photogrammetry to obtain point clouds, enabled post-field studies, particularly for fracture systems that are complex, inaccessible, or large in scale. Additionally, SEFL offers a tool based on the concept of fracture stratigraphy to identify mechanical units, which are essential frameworks for measuring and calculating fracture properties. This new methodology has been applied to study the fractured Eocene limestone outcrop at the hinge of the Añisclo anticline (South-Central Pyrenees, NE Iberia) which has been digitally acquired and characterized. SEFL output data interpretations revealed an outcrop characterized by over two thousand modelled fractures, five fracture sets, fourteen fracture stratigraphic units, and 1-2 fractures/m.

Information enhanced slow feature analysis integrated with prior fault data for sensitive monitoring of chemical processes

As an effective feature extraction method, slow feature analysis (SFA) has been successfully applied in the domain of chemical process monitoring. However, as an unsupervised method, the basic SFA ignores the key information carried by prior fault data so that many complicated faults cannot be sensitively detected. To address this issue, an enhanced SFA method, termed Information Enhanced SFA (IE-SFA), is proposed by integrating available fault discriminant information to achieve more sensitive detection of complicated chemical process faults. The proposed method builds a primary-auxiliary SFA modeling framework. On the one hand, the normal training data are analyzed to establish the primary SFA model. On the other, prior fault data are integrated to develop an auxiliary monitoring model for providing extra fault-sensitive information. In the auxiliary model, a sample-variable weighted Fisher discriminant analysis method is performed on normal data, fault data, and their respective slow feature components, thereby extracting fault-sensitive features for enhancing the fault detection capability. For full-view fault monitoring, the Bayesian fusion strategy is used to fuse the outcomes from both primary and auxiliary models. The applications on a benchmark Tennessee Eastman chemical process and a three-phase flow process demonstrate that the proposed IE-SFA method provides superior fault detection performance compared to the basic SFA method.

Modeling of long-term radiological and toxicological impacts of the uranium mill tailings on groundwater and surface water

Modeling predictions are presented of radionuclide transport processes in the zone of influence of the Zahidne uranium mill tailings situated at the Prydniprovsky Chemical Plant (PChP), Kamianske. The groundwater transport model was developed using the NORMALYSA software. Refined estimates of parameters of water exchange in the zone of uranium mill tailing (obtained from field studies and modeling of groundwater flow processes) were used to parameterize the model for radionuclide transport in groundwater. Calibration of the radionuclide transport model using monitoring data on radioactive contamination of groundwater in 2005 - 2021 allowed to estimate the sorption distribution coefficient (Kd) for the most hazardous contaminants 238,234U isotopes (Kd = 8 ± 2 l/kg) and estimate the rate of uranium migration in groundwater. According to modeling, during the next 800 to 1100 years, uranium concentration in wells in the zone of influence of uranium mill tailing (at 500 - 800 m distance) will be determined mainly by the contamination of the alluvial aquifer, which was formed during the operation period of the uranium mill tailing. According to modeling predictions, usage of groundwater (partial drinking water consumption, irrigation) outside the PChP site downstream of the uranium mill tailing will result in doses exceeding the relevant reference level (annual effective dose > 1 mSv/year) in 380 - 440 years, while the toxicological impact will result in the exceeding of the acceptable hazard index for uranium (HI > 1) in 200 - 260 years. Modeling results indicate the importance of restricting the use of groundwater downstream of the uranium mill tailing within the PChP industrial site and, in the longer term, beyond its boundary. At the same time, contamination of the Konoplyanka River due to the migration of radionuclides from the uranium mill tailing does not pose unacceptable radiological and toxicological risks for the considered scenario (irrigation, fish consumption) due to the dilution of contaminants in surface waters.

Magnetohydrodynamic Analysis and Fast Calculation for Fractional Maxwell Fluid with Adjusted Dynamic Viscosity

From the perspective of magnetohydrodynamics (MHD), the heat transfer properties of Maxwell fluids under MHD conditions with modified dynamic viscosity present complex challenges in numerical simulations. In this paper, we develop a time-fractional coupled model to characterize the heat transfer and MHD flow of Maxwell fluid with consideration of the Hall effect and Joule heating effect and incorporating a modified dynamic viscosity. The fractional coupled model is numerically solved based on the L1-algorithm and the spectral collocation method. We introduce a novel approach that integrates advanced algorithms with a fully discrete scheme, focusing particularly on the computational cost. Leveraging this approach, we aim to significantly enhance computational efficiency while ensuring accurate representation of the underlying physics. Through comprehensive numerical experiments, we explain the thermodynamic behavior in the MHD flow process and extensively examine the impact of various critical parameters on both MHD flow and heat transfer. We establish an analytical framework for the MHD flow and heat transfer processes, further investigate the influence of magnetic fields on heat transfer processes, and elucidate the mechanical behavior of fractional Maxwell fluids.

A finite volume–based thermo-fluid-mechanical model of the LPBF process

The multi-physics coupling feature of the laser powder bed fusion (LPBF) process poses great challenges to numerical models regarding computational fidelity and efficiency. This paper proposed a finite volume–based model for predicting integrated thermo-fluid-mechanical behaviors of the LPBF process. The model directly unifies the heat transfer, fluid flow and solid mechanics simulations within a predefined mesh, enabling simultaneous solutions for the fluid domain under Eulerian description and the solid domain under Lagrangian description. Three benchmark tests accounting for individual problems were conducted to validate the model's accuracy and effectiveness. Track-scale LPBF simulations were performed to unravel the intricate interplay between thermal, fluid and mechanical behaviors. The numerical predictions of surface morphologies, molten pool dynamics and melt track dimensions aligned well with the experimental observations. The spatiotemporal evolution of transient thermal stress was accurately captured and the predicted residual stress field showed consistency with nanoindentation measurements. The proposed model was found robust in simultaneously predicting the temperature distribution, melt flow and residual stress evolutions of the LPBF process, and showed strong potential for addressing other similar multi-physics coupling problems.

Numerical modeling of the impact of a large scale waterfall on a solid plate

Recent hydroelectric power plant safety developments have necessitated detailed studies on dam spillway operations, especially during emergency water discharge scenarios such as overtopping. This paper presents a numerical investigation of a 10-meter high waterfall impinging on a solid plate using two-phase flow models. Our approach integrates a coupled Eulerian–Lagrangian Spray Atomization (ELSA) model with an Interface Capturing Method (ICM) to simulate the complex multiphase flow and atomization processes. Our model proficiently mapped the velocity and turbulence within the pre-impact region. To refine the accuracy of the impact pressures, we isolated this zone and implemented the Injection–Reinjection strategy, a novel numerical procedure for this type of configuration. The study reveals significant insights into the dynamic interactions of water packets with the dam structure, highlighting critical impact pressures that can influence dam stability and integrity. Our results, compared against experimental data, demonstrate the effectiveness of the modeling strategies in predicting the fluid behaviors and the subsequent pressures exerted on structural components.

Research on the evolution mechanism of surface morphology and solidification crystallization simulation of molten pool in electron beam polishing

Clarifying the flow and solidification process rules of a molten pool in scanning electron beam polishing remains challenging. This paper establishes a geometric model that closely resembles the original milling morphology, investigates the morphology evolution process, the flow law of the molten pool, and the change in driving force under the action of the electron beam, and solves the solidification and crystallization parameters of the solid-liquid interface. Results demonstrate that thermocapillary force is the dominant driving factor for horizontal motion inside the molten pool, which immediately leads to the emergence of velocity conversion sites on the surface of the molten pool, thus effecting surface fluctuation variations. Combined with polishing inspection, the average surface roughness error is controlled within ±7 %. Solid-liquid interface deflection significantly affects grain growth, and solidification and crystallization parameters follow similar patterns at different workpiece speeds. The grain structure of the melt zone can be predicted with the crystallization parameters at various depths of the melt layer.

Progress of joint process research on purification of high purity quartz sand

High-purity quartz sand is an important raw material for semiconductors, photovoltaics, aerospace and other cutting-edge fields, high-quality natural crystals can no longer meet the urgent demand for high-purity quartz in the domestic market, and it is imperative to accelerate the realisation of high-quality quartz purification technology from non-quality mineral sources. This paper summarises the joint process flow in the unused scenario, and outlines the main methods for the purification of quartz sand in China at present, including pretreatment, ultrasound-assisted leaching, chlorination roasting, etc., from the point of view of the joint process, and puts forward the problems that exist in these methods, so as to provide certain references for the research on the purification process of high-purity quartz sand in China.

Achieving low-porosity AlSi10Mg cladding layers for the additive repair of aluminum alloy parts by directed energy deposition

Directed Energy Deposition (DED) has broad application prospects for repairing damaged aluminum alloy parts such as piston aero-engine casing. However, due to the low laser absorptivity and the complex thermal cycle process, it is challenging to obtain aluminum alloy cladding layers with high-quality morphology and low-porosity by DED method. In this work, a series of individual stages of DED process are studied during single-tracks overlapping and layers stacking. Correspondingly, the within layer scanning strategy, inter-layer stacking strategy, and process parameters are examined carefully. Using the proposed DED processing flow that combines substrate preheating with intermittent process, the deposited layers without balling and collapse are successfully achieved. Furtherly, the bi-directional scanning strategy for single-tracks overlapping within layer is proposed to compensate the thickness nonuniformity caused by heat accumulation. The inter defects identified as “lack of fusion” and “gas pores” are observed in the cladding layers with uniform surface. By analyzing the pore formation mechanism and considering the energy distribution and re-melting, the multi-layer offset stacking strategy is proposed to inhibit the porosity to 0.25 %. Combined with the optimized process parameters, the porosity is reduced up to 0.09 %, ensuring the density of the DED deposition coating. This work provides new pathway and direct guidance for fabricating high-quality AlSi10Mg cladding layers during the DED repairing of valuable aluminum alloy parts.

A new evaluation method for sand control performance of slotted screen

Evaluation method of slotted screen performance is a critical concern for sand control. Despite its significance, comprehensive investigations into quantitative study of sand retaining during the complex flow process need further in-depth study, particularly in numerical simulation research model of the slotted screen. This paper adopts the two-way coupling calculation method of computational fluid dynamics (CFD) and discrete element method (DEM) for the particle movement and fluid flow at the slotted screen and establishes a numerical model of the sand particle migration process through the slotted screen. The sand particle deposition and plugging dynamics on the surface of the sand retaining medium and the micro sand plugging mechanism and blockage pattern are studied. The fractal dimension of formation sand is introduced to characterize different distribution of formation sand. The effects of fluid viscosity, width of the slotted screen, sand production concentration, fluid velocity and particle size distribution on sand production, sand passing rate and particle size distribution of formation sand passing through the slot and plugging behavior are studied. The sand plugging process of slotted screen can be divided into three stages: the beginning of blockage, the intensification of blockage, and the balance of blockage. Under simulated conditions, the initial sand plugging rate is 87%, and as the blockage intensifies, the sand plugging rate gradually increases to 96.5%. Based on the analysis of numerical simulation results, the index of total seepage resistance damage amplitude and velocity, general sand retention ratio and passed-sand size were defined to construct the integrated evaluation method of slotted screen media, which involves the performance of sand retention, anti-plugging and flow ability. A brand new set of ideas on quantifying the integrated evaluation method were introduced to calculate the individual and integrated performance indicators of the slotted screen based on simulated data. The quantitative evaluation of the sand control performance of the slotted screen provides guidance and reference for the parameter design of the slotted screen in the target oil region and the accuracy optimization of the sand control medium.