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Records added in February 2023
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1951. LAPSE:2023.11276
In-Situ Hydrothermal Synthesis of Ag3PO4/g-C3N4 Nanocomposites and Their Photocatalytic Decomposition of Sulfapyridine under Visible Light
February 27, 2023 (v1)
Subject: Materials
Keywords: Ag3PO4, g-C3N4, photocatalysis, sulfapyridine, visible light
Highly efficient visible-light-driven heterogeneous photocatalyst Ag3PO4/g-C3N4 with different weight ratios from Ag3PO4 to g-C3N4 were synthesized by a facile in situ hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR), photoluminescence spectra (PL), UV−vis diffuse reflectance spectra (UV-Vis), and electrochemical impedance spectra (EIS). Under visible light irradiation, Ag3PO4/g-C3N4 showed very excellent photocatalytic activity for sulfapyridine (SP) which is one of the widely used sulfonamide antibiotics. When the ratio from Ag3PO4 to g-C3N4 was 1:2, the degradation rate of SP at 120 min was found to be 94.1%, which was superior to that of pure Ag3PO4 and pure g-C3N4. Based on the experimental results, the possible enhanced photocatalytic mechanism of Ag3PO4/g-C3N4 was proposed.
1952. LAPSE:2023.11275
Influence of Prefermentative Cold Maceration on the Chemical and Sensory Properties of Red Wines Produced in Warm Climates
February 27, 2023 (v1)
Subject: Biosystems
Keywords: bottle aging, prefermentative cold maceration, red wine, warm climate, wine aromatic profile
Red wines produced in warm climates generally possess a lower content of phenolic compounds and color structure than those produced in colder climates, which hinders bottle evolution. To improve these properties, cold maceration could be a useful procedure. To study the effect of this technique, Tempranillo, Merlot and Syrah grape varieties cultivated in the Jerez area (Southwest Spain) were cold macerated at 4 °C for ten days before alcoholic fermentation. Their composition and characteristics compared to the directly fermented control grapes were analyzed for phenolic content, color, volatile compounds, and sensory properties. It has been verified that phenolic content increased by around 10% during the treatment, which was maintained after the alcohol fermentation, along with an increase in color intensity and aromatic profile. This modification on the composition provided better scores for appearance, aroma intensity, and aroma quality in sensory analysis. The evolution of all stud... [more]
1953. LAPSE:2023.11274
Determination of Electrogenic Potential and Removal of Organic Matter from Industrial Coffee Wastewater Using a Native Community in a Non-Conventional Microbial Fuel Cell
February 27, 2023 (v1)
Subject: Biosystems
Keywords: agro-industrial wastewater, coffee waste, electroactive, MFC, microbial fuel cell, native microbial community
Microbial fuel cells (MFCs) are an alternative to conventional wastewater treatments that allow for the removal of organic matter and cogeneration of electrical energy, taking advantage of the oxidation−reduction metabolism of organic compounds conducted by microorganisms. In this study, the electrogenic potential and the capacity for the reduction of the organic matter of native microbial communities in wastewater from the wet processing of coffee were evaluated using open-cathode MFCs. To determine the electrogenic potential, a factorial experimental design was proposed in which the origin of the residual water and the source of the inoculum were evaluated as factors. The MFCs operated for 21 days in both open-circuit and closed-circuit operation modes. Voltage records, current determinations, and chemical oxygen demand (COD) analyses were used to establish the power reached in the electrochemical system and the degree of the decontamination of the wastewater. During the MFC operatio... [more]
1954. LAPSE:2023.11273
Development of Experimental Techniques for the Phase Equilibrium Study in the Pb-Fe-O-S-Si System Involving Gas, Slag, Matte, Lead Metal and Tridymite Phases
February 27, 2023 (v1)
Subject: Environment
Keywords: lead matte, lead metal, lead slag, phase equilibria experiments
Present society challenges, including metal scarcity, recycling, and environmental restrictions, resulted in the increased complexity and variability of metallurgical feed streams. Metallurgical processes involving complex lead and copper-containing slag and matte phases are now commonly used in response. Optimization of existing and development of new metallurgical processes require fundamental information on slag−matte phase equilibrium. Development of the experimental methodology for the characterization of slag−matte phase equilibrium is presented in the paper. Following a detailed analysis of the potential reaction pathways, experimental techniques have been developed that enable accurate measurement of slag−matte phase equilibrium in the Pb-Fe-O-S-Si system. The application of the techniques has been demonstrated for two important sets of conditions: (i) Condensed phase equilibrium for the slag−matte−metal−tridymite subsystem; and (ii) Gas−slag−matte−tridymite equilibrium at fixe... [more]
1955. LAPSE:2023.11272
Robustness Evaluation Process for Scheduling under Uncertainties
February 27, 2023 (v1)
Subject: Planning & Scheduling
Keywords: decision making, discrete event systems, Industry 4.0, production scheduling, robustness evaluation, uncertainties
Scheduling production is an important decision issue in the manufacturing domain. With the advent of the era of Industry 4.0, the basic generation of schedules becomes no longer sufficient to face the new constraints of flexibility and agility that characterize the new architecture of production systems. In this context, schedules must take into account an increasingly disrupted environment while maintaining a good performance level. This paper contributes to the identified field of smart manufacturing scheduling by proposing a complete process for assessing the robustness of schedule solutions: i.e., its ability to resist to uncertainties. This process focuses on helping the decision maker in choosing the best scheduling strategy to be implemented. It aims at considering the impact of uncertainties on the robustness performance of predictive schedules. Moreover, it is assumed that data upcoming from connected workshops are available, such that uncertainties can be identified and model... [more]
1956. LAPSE:2023.11271
Enzymatic Hydrolysis of Complex Carbohydrates and the Mucus in a Mathematical Model of a Gut Reactor
February 27, 2023 (v1)
Subject: Biosystems
Keywords: chemostat model, compartments, dietary fiber, gut model, hydrolysis, mucins
The human gut microbiota rely on complex carbohydrates for energy and growth, particularly dietary fiber and host-produced mucins. These complex carbohydrates must first be hydrolysed by certain microbial groups to enable cross-feeding by the gut microbial community. We consider a mathematical model of the enzymatic hydrolysis of complex carbohydrates into monomers by a microbial species. The resulting monomers are subsequently digested by the microbial species for growth. We first consider the microbial species in a single compartment continuous stirred-tank reactor where dietary fiber is the only available substrate. A two compartment configuration in which a side compartment connected by diffusion is also studied. The side compartment is taken to be the mucus layer of the human colon, providing refuge from washout and an additional source of complex carbohydrate in the form of mucins. The two models are studied using stability analysis, numerical exploration, and sensitivity analysi... [more]
1957. LAPSE:2023.11270
A Review of Real-Time Fault Diagnosis Methods for Industrial Smart Manufacturing
February 27, 2023 (v1)
Subject: Process Monitoring
Keywords: AI, industrial process monitoring, industrial smart manufacturing, machine condition monitoring, RTFD
In the era of Industry 4.0, highly complex production equipment is becoming increasingly integrated and intelligent, posing new challenges for data-driven process monitoring and fault diagnosis. Technologies such as IIoT, CPS, and AI are seeing increasing use in modern industrial smart manufacturing. Cloud computing and big data storage greatly facilitate the processing and management of industrial information flow, which helps the development of real-time fault diagnosis (RTFD) technology. This paper provides a comprehensive review of the latest RTFD technologies in the field of industrial process monitoring and machine condition monitoring. The RTFD process is introduced in detail, starting with the data acquisition process. The current RTFD methods are divided into methods based on independent feature extraction, methods based on “end-to-end” neural networks, and methods based on qualitative knowledge reasoning from a new perspective. In addition, this paper discusses the challenges... [more]
1958. LAPSE:2023.11269
Dataset of 3β-Corner and 3β-Corner-like Structures
February 27, 2023 (v1)
Subject: Biosystems
Keywords: 3β-corner, 3β-corner-like structure, dataset, structural motif of a protein
The study is devoted to the creation of a dataset of protein structural motifs of the 3β-corner type. The relevance and importance of creating a dataset of 3β-corners is determined by the fact that this structure can be an embryo or a ready-made structural block in the process of protein folding, and can also act as an independent object of research in the field of structural biology. The dataset also contains 3β-corner-like structures that are geometrically similar to 3β-corners. The dataset consists of 45,896 structures. For each motif, its characteristics are presented: the name of the protein in which the 3β-corner is recognized, the method and resolution of the protein structure, the coordinates of localization in the protein, the secondary structure of the amino acid sequence, the gyration radius, the solvent-accessible area, and the composition of the elements of the secondary structure. The dataset will allow a comprehensive study of structures on a large scale and advance the... [more]
1959. LAPSE:2023.11268
Study on the Shadow Effect of the Stress Field around a Deep-Hole Hydraulic-Fracturing Top-Cutting Borehole and Process Optimization
February 27, 2023 (v1)
Subject: Energy Systems
Keywords: fluid–solid coupling, fracture mechanics, prescribed hydraulic fracturing, stress shadow effect
The clean utilization and green development of coal resources have become a research focus in recent years. Underground hydraulic fracturing technology in coal mines has been widely used in roof pressure relief, top coal pre-splitting, gas drainage, roadway pressure relief and goaf disaster prevention. Different in situ stress types cause great differences in the stress field around the boreholes, the critical pressure of the fracture initiation, and the direction of the fracture expansion trend; in addition, the stress shadow effect generated by the superposition of stress fields between boreholes relatively close together has a mutual coupling effect on the evolution of the stress field, the development of the plastic zone, and the crack propagation of the rock mass. Therefore, an effective method to solve the problem is to establish a mechanical model of hydraulic fracturing in boreholes for theoretical calculation, determine the influence mechanism of the crack shadow effect, and d... [more]
1960. LAPSE:2023.11267
Optimization of an Indoor DWC Hydroponic Lettuce Production System to Generate a Low N and P Content Wastewater
February 27, 2023 (v1)
Subject: Optimization
Keywords: daily light integral, deep-water culture, Lactuca sativa L., light-use efficiency, N and P removal, water-use efficiency
Hydroponic production raises economic and environmental issues related to the treatment, recovery or disposal of hydroponic wastewater, which can be rich in eutrophication-related nutrients, nitrogen (N) and phosphorus (P). Little focus has been put on the influence of the growth conditions on the N and P content in hydroponic wastewater, which is of uttermost importance when it is intended to reuse the wastewater for irrigation or other purposes with reduced impact on the environment. This study aimed to optimize an indoor non-recirculating deep-water culture (DWC) hydroponic system for lettuce (Lactuca sativa L. var. crispa) production, in terms of daily light integral (DLI) and volume of nutrient solution (NS) per plant, to maximize both the biomass production and the N and P removal, allowing for the wastewater to meet the criteria established for reusing in irrigation and minimizing the eutrophication impacts. A small-scale DWC hydroponic system with a fluorescent light fixture wa... [more]
1961. LAPSE:2023.11266
Reuse of Carbon Fibers and a Mechanically Recycled CFRP as Rod-like Fillers for New Composites: Optimization and Process Development
February 27, 2023 (v1)
Subject: Optimization
Keywords: carbon fiber reinforced polymers, polymer composites, properties optimization, recycling processes
The rising amount of carbon fiber reinforced polymer (CFRP) composite waste requires new processes for reintroducing waste into the production cycle. In the present research, the objective is the design and study of a reuse process for carbon fibers and CFRP by mechanical recycling consisting of length and width reduction, obtaining rods and reintegrating them as fillers into a polymeric matrix. Preliminary studies are carried out with continuous and discontinuous unidirectional fibers of various lengths. The processing conditions are then optimized, including the length of the reinforcement, the need for a plasma surface treatment and/or for resin post-curing. The resin is thermally characterized by differential scanning calorimetry (DSC), while the composites are mechanically characterized by tensile strength tests, completed by a factorial design. In addition, the composites tested are observed by scanning electron microscopy (SEM) to study the fracture mechanics. Optimal processing... [more]
1962. LAPSE:2023.11265
Optimization and Prediction of Stability of Emulsified Liquid Membrane (ELM): Artificial Neural Network
February 27, 2023 (v1)
Subject: Numerical Methods and Statistics
Keywords: artificial neural network, emulsification time, emulsified liquid membrane (ELM), Span 80, stability, stirring speed
In this work, the emulsified liquid membrane (ELM) extraction process was studied as a technique for separating different pollutants from an aqueous solution. The emulsified liquid membrane used consisted of Sorbitan mono-oleate (Span 80) as a surfactant with n-hexane (C6H14) as a diluent; the internal phase used was nitric acid (HNO3). The major constraint in the implementation of the extraction process by an emulsified liquid membrane (ELM) is the stability of the emulsion. However, this study focused first on controlling the stability of the emulsion by optimizing many operational factors, which have a direct impact on the stability of the membrane. Among the important parameters that cause membrane breakage, the surfactant concentration, the emulsification time, and the stirring speed were demonstrated. The optimization results obtained showed that the rupture rate (Tr) decreased until reaching a minimum value of 0.07% at 2% of weight/weight of Span 80 concentration with an emulsif... [more]
1963. LAPSE:2023.11264
Water Cleaning by a Continuous Fixed-Bed Column for Cr(VI) Eco-Adsorption with Green Adsorbent-Based Biomass: An Experimental Modeling Study
February 27, 2023 (v1)
Subject: Modelling and Simulations
Keywords: chromate, eco-adsorption, fixed bed, process modeling, red peanut skin, Wastewater
In this study, chromate adsorption onto red peanut skin (RPS) was investigated in a fixed-bed column; FTIR, PZC, SEM, DLS, and BET were used to evaluate its adsorption properties. The experiments were conducted to determine the effect of physical parameters, including the inlet initial Cr(VI) concentration (100−500 mg L−1), bed height (10−20 cm), and feed flow rate (13.59−23.45 mL min−1). They were carried out to predict breakthrough curves. The adsorption capacity coefficients were determined using the most widely used Bohart−Adams model. It was tested to fit experimental data, for a better understand the dynamic behavior, and for further optimize column performance. It was found that the Cr(VI) uptake decreases when increasing the flow rate and that high chromate concentration and bed height consequently increase the column’s life span. A high column adsorption capacity can be achieved with a higher Cr(VI) concentration due to the higher driving force. The results indicated that the... [more]
1964. LAPSE:2023.11263
Biogas Production from Residues of Industrial Insect Protein Production from Black Soldier Fly Larvae Hermetia illucens (L.): An Evaluation of Different Insect Frass Samples
February 27, 2023 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, black soldier fly, BMP tests, CSTR digestion, Hermetia illucens, insect frass
Insect biomass shows promise as an alternative animal feedstuff with a low climate effect. Industrial insect rearing generates residual materials, such as feed remains and insect excrements, so-called insect frass, which exhibits a high organic content. Commonly, these residues are utilized as soil amendment. Information on the suitability of these residues for biogas production is rather scarce. The energetic utilization of insect frass as feedstock for anaerobic digestion (AD) would allow for the simultaneous residue material reduction and bioenergy production. Additionally, synergies in heat management could arise using the exhaust heat of the biogas plant in the insect farming process. In laboratory-scale anaerobic digestion trials, the specific methane yield (SMY) of six different insect frass samples from black soldier fly (Hermetia) rearing were tested in batch biochemical methane potential (BMP) tests. Further, semi continuous anaerobic digestion trials on a lab scale using con... [more]
1965. LAPSE:2023.11262
Recent Progress of Non-Pt Catalysts for Oxygen Reduction Reaction in Fuel Cells
February 27, 2023 (v1)
Subject: Energy Systems
Keywords: alloy catalysts, high-entropy alloy catalysts, non-metallic catalysts, ORR, single-atom catalysts (SACs)
In recent years, non-Pt-based ORR catalysts have been developing rapidly and have achieved performance comparable to or even surpassing Pt precious metal catalysts in specific reactions, offering new possibilities for Pt-based catalyst replacement and showing great promise for application. This paper reviews the recent research progress of non-Pt-based fuel cell ORR catalysts. The latest research progress of non-Pt-based ORR SACs (including single metal active site ORR SACs, multi-metal active site ORR SACs, and non-Pt-based noble metal catalyst ORR SACs), non-metallic ORR catalysts, alloy-based ORR catalysts, high-entropy alloy ORR catalysts, and other non-Pt-based fuel cell ORR catalysts are presented in detail. This paper discusses in detail the synthesis methods, characterization means, optimization of performance, and application prospects of these non-Pt-based ORR catalysts. In addition, this review details the excellent performance of these catalysts in terms of compositional an... [more]
1966. LAPSE:2023.11261
Optimized Process for Melt Pyrolysis of Methane to Produce Hydrogen and Carbon Black over Ni Foam/NaCl-KCl Catalyst
February 27, 2023 (v1)
Subject: Process Design
Keywords: carbon black, Hydrogen, melt pyrolysis of methane, Ni foam
Methane pyrolysis transforming CH4 into hydrogen without a CO2 byproduct is a potential hydrogen production process under the net-zero emission target. The melt pyrolysis of methane is a technology that could simultaneously obtain hydrogen and carbon products. However, its catalytic activity and stability are still far from satisfactory. In this work, a new strategy for the melt pyrolysis of methane to hydrogen production was proposed using Ni foam and molten NaCl-KCl. The increase in the amount of Ni foam was found to enhance the methane conversion rate from 12.6% to 18%. The process was optimized by the different amounts of catalysts, the height of the Ni foam layer, and the filling method of Ni foam, indicating that the methane conversion rate of the string method could reach 19.2% at 900 °C with the designed aeration device. Furthermore, we observed that the addition of molten salt significantly alleviated the carbon deposition deactivation of the Ni foam and maintained its macrost... [more]
1967. LAPSE:2023.11260
Treatment Wetlands in Mexico for Control of Wastewater Contaminants: A Review of Experiences during the Last Twenty-Two Years
February 27, 2023 (v1)
Subject: Environment
Keywords: constructed wetlands, ornamental plants, phytoremediation, wastewater treatment
Constructed or treatment wetlands (CWs) are a sustainable option to clean wastewater in the face of water pollution problems. Consequently, this study was aimed at reviewing and analyzing the use of CWs in Mexico. This involved types, sizes, and functionality in the removal of pollutants, as well as the main plant species that are used. Furthermore, 67 studies regarding CWs were found, which were classified according to the treatment area as microcosms, mesocosms, pilot scale, and full-scale at 18, 30, 25, and 27%, respectively. The most used types of CWs are those of subsurface flow (87%) versus free-water surface (13%), of which horizontal flow direction (58%) are the most common. Considering Full-Scale CWs, the pollutant removal reported for COD, BOD5, TN, and TP oscillated between 50−90%, 60−90%, 30−90%, and 30−70%, respectively. Among the vegetation that is more used for Mexican CWs, 78 different species were detected; Typha and Cyperus hydrophytes species and ornamental flowering... [more]
1968. LAPSE:2023.11259
New Perspective on Comparative Chemometric and Molecular Modeling of Antifungal Activity and Herbicidal Potential of Alkyl and Cycloalkyl s-Triazine Derivatives
February 27, 2023 (v1)
Subject: Modelling and Simulations
Keywords: Aspergillus flavus, chemometrics, molecular docking, molecular modeling, pesticides, triazines
The contamination of the environment by pesticides is becoming a burning issue in many countries in the World. Development, design, and synthesis of new eco-friendly pesticides and modification of existing ones in order to improve their efficacy with the lowest impact on the environment are two main future possibilities in crop protection and the provision of sufficient food for the growing world population. The present study is focused on the comparative analysis of a series of eight symmetrical triazine derivatives, as potential herbicide candidates with acyclic (alkyl) and cyclic (cycloalkyl) substituents, in terms of their antifungal activity towards Aspergillus flavus as an opportunistic fungal pathogenic microorganism responsible for frequent contaminations of crops with aflatoxin, and in terms of their potential application as herbicides in maize, common wheat, barley, and rice crops. The applied methods include the chemometric pattern recognition method (hierarchical cluster an... [more]
1969. LAPSE:2023.11258
Thermodynamic and Heat Transfer Performance of the Organic Triangle Cycle
February 27, 2023 (v1)
Subject: Energy Systems
Keywords: low-grade energy, organic triangle cycle, thermodynamics analysis
Compared to the organic Rankine cycle (ORC), the organic triangle cycle (TC) is simpler in structure and is not limited by pinch point temperature differences. TC has been studied to some extent by previous researchers, such as the selection of working fluid, application, and the design of the expander. However, system optimization and parameter analysis of TC are still rare. The thermodynamic performance of TC internal circulation and TC heat recovery systems are investigated by theoretical analysis and numerical simulation, respectively. The results indicate that the expander inlet temperature T3 and heater inlet temperature T2 are key elements impacting the thermodynamic performance of the TC internal circulation. For the TC heat recovery system, an optimal value of the average heat-capacity flow rate of working fluid Cwf is discovered to output the maximum net power output Wnet. Moreover, the total heat transfer coefficients for the heater (kA)h and condenser (kA)c are discussed in... [more]
1970. LAPSE:2023.11257
Study on the Hydrodynamic Performance of a Countercurrent Total Spray Tray under Sloshing Conditions
February 27, 2023 (v1)
Subject: Process Operations
Keywords: countercurrent total spray tray, hydrodynamic performance, offshore conditions, pressure drop, sloshing platform
In this paper, a new type of total spray tray (TST) with gas−liquid countercurrent contact is proposed to solve the problem of slight operation flexibility and poor sloshing resistance in towers under offshore conditions. Its hydrodynamic performance indicators, such as pressure drop, weeping, entrainment, and liquid level unevenness, were experimentally studied under rolling motion. A tower with an inner diameter of 400 mm and tray spacing of 350 mm was installed on a sloshing platform to simulate offshore conditions. The experimental results show that the rolling motion affected the hydrodynamic performance of the tray under experimental conditions. When the rolling amplitude did not exceed 4°, the degree of fluctuation of the hydrodynamic performance was small, and the tray could still work stably. With increasing rolling amplitude, the TST wet plate pressure drop, weeping, and liquid level unevenness fluctuations also increased. When the rolling amplitude reached 7°, the maximum fl... [more]
1971. LAPSE:2023.11256
An Effective Methanol-Blocking Cation Exchange Membrane Modified with Graphene Oxide Nanosheet for Direct Methanol Fuel Cells
February 27, 2023 (v1)
Subject: Energy Systems
Keywords: cellulose acetate, direct methanol fuel cell, grafting, graphene oxide, permeability
Herein, graphene oxide nanosheets (GO) were synthesized and employed as an additive at various proportions to fabricate a novel cation exchange membrane based on grafted cellulose acetate with sodium 4-styrenesulfonate (GCA) via a solution casting method for direct methanol fuel cell (DMFC) applications. The structure of composite membranes has been examined using FTIR, TGA, SEM, and DSC. The physicochemical properties of the GCA/GO membranes, such as ion exchange capacity, water uptake, mechanical and chemical stability, methanol permeability, and proton conductivity, were measured. The inclusion of GO significantly improved the ability to block methanol, contributing to the observed effects. Among the several composite membranes developed, GCA/GO (2 wt.%) had the highest selectivity with a water uptake of 45%, proton conductivity of 5.99 × 10−3 S/cm, methanol permeability of 1.12 × 10−7 cm2/s, and electrical selectivity of 26.39 × 103 Ss/cm3. Simultaneously, the composite membranes’... [more]
1972. LAPSE:2023.11255
Single-Step Fabrication of a Dual-Sensitive Chitosan Hydrogel by C-Mannich Reaction: Synthesis, Physicochemical Properties, and Screening of its Cu2+ Uptake
February 27, 2023 (v1)
Subject: Environment
Keywords: chitosan, dual responsive, environmental engineering, heavy metal removal, hydrogel, Mannich reaction, water treatment
Uncovering the value of waste materials is one of the keys to sustainability. In this current work, valorization of chitosan was pursued to fabricate a novel modified chitosan functional hydrogel using a process-efficient protocol. The fabrication proceeds by a one-pot and single-step C-Mannich condensation of chitosan (3% w/v), glutaraldehyde (20 eq.), and 4-hydroxycoumarin (40 eq.) at 22 °C in 3% v/v acetic acid. The Mannich base modified chitosan hydrogel (CS-MB) exhibits a dual-responsive swelling behavior in response to pH and temperature that has not been observed in any other hydrogel systems. Combining the pre-defined optimal swelling pH (pH = 4) and temperature (T = 22 °C), the CS-MB was screened for its Cu2+ adsorption capacity at this condition. The CS-MB achieved an optimal adsorption capacity of 12.0 mg/g with 1.2 g/L adsorbent dosage after 36 h with agitation. The adsorption of Cu2+ on the surface of CS-MB was verified by EDS, and an overview of the adsorption sites was e... [more]
1973. LAPSE:2023.11254
SAPEVO-H² a Multi-Criteria Systematic Based on a Hierarchical Structure: Decision-Making Analysis for Assessing Anti-RPAS Strategies in Sensing Environments
February 27, 2023 (v1)
Subject: Environment
Keywords: anti-RPAS strategies, hierarchical model, multi-criteria, SAPEVO-M method
Regarding high-level and complex decision-making scenarios, the study presents an extensive approach to the Simple Aggregation of Preferences Expressed by Ordinal Vectors-Multi Decision Making method (SAPEVO-M). In this context, the modeling proposal, named SAPEVO-Hybrid and Hierarchical (SAPEVO-H²), the objective of this study, based on the concepts of multi-criteria analysis, provides the evaluation of alternatives under the light of multiple criteria and perceptions, enabling the integration of the objectives of a problem, which are transcribed into attributes and structured in a hierarchical model, analyzing qualitative and quantitative data through ordinal and cardinal entries, respectively. As a case study, a decision analysis concerning the defense strategies against anti-Remotely Piloted Aircraft Systems (RPAS) strategies for the Brazilian Navy is carried out. Using the technique of the causal maps approach based on Strategic Options Development and Analysis (SODA) methodology,... [more]
1974. LAPSE:2023.11253
Chemical Behaviour of Copper in the Application of Unconstrained Cr-Ni-Al-Cu Metal Powders in Submerged Arc Welding: Gas Phase Thermodynamics and 3D Slag SEM Evidence
February 27, 2023 (v1)
Subject: Materials
Keywords: aluminium deoxidiser, chromium, copper, nickel, partial oxygen pressure, powder, pyrometallurgy, welding
Unconstrained metal powders of Cu, Cr, Ni and Al were applied to submerged arc welding (SAW) to clarify the chemical behaviour of copper in this modified SAW process. Aluminium metal is avoided in SAW because it is easily oxidised. Excessive aluminium oxides in the form of slag or inclusions in the weld metal will lead to poor weld metal materials properties. Aluminium is an effective deoxidiser and can be used to prevent Cr and Ni loss to the slag by preventing oxidation of these metals. The results show that carbon steel was alloyed to 5.3% Cr, 5.3% Ni, 3.6% Al and 5.2% Cu at 80% Cr yield, 81% Ni yield, 54% Al yield and 79% Cu yield. BSE (backscattered electron) images of the three-dimensional (3D) post-weld slag sample show 3D structures within the slag dome. The 3D structures contain features of vapour formation and recondensation. In addition, nano-strands appear in the 3D structures and confirm the vaporisation and recondensation of fluorides. The chemical behaviour of copper met... [more]
1975. LAPSE:2023.11252
Case Study on Pre-Splitting Blasting Reasonable Parameters of Goaf-Side Entry Retained by Roof Cutting for Hard Main Roof
February 27, 2023 (v1)
Subject: Process Design
Keywords: fissure rate, goaf-side entry by roof cutting, hard main roof, newly designed strategy, pressure relief pre-splitting blasting technology
The key parameters of pressure relief pre-splitting blasting technology (PRPBT) contribute to the implementation effect of goaf-side entry by roof cutting (GSERC). This study is an attempt to design the key parameters including the roof cutting height, the roof cutting angle, the spacing between blasting boreholes, the charge structure and the sealing length by using theoretical analysis, numerical simulation and field implementation. The basic quality index of the main roof is 666.27, and combined with the peeping observation result, the main roof belongs to the category of a hard main roof. Different from a weakened roof and a compound roof, the unreasonable parameters of the PRPBT for the hard main roof lead to three problems including an insufficient pre-splitting blasting effect, roof suspension in the goaf and serious damage to the rock mass for the roof cutting rib. The PRPBT effect is closely related to key parameters, including the roof cutting parameters and the pre-splitting... [more]
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