Influence Of Different Processing Conditions Research Articles

Continuous glass fiber‐reinforced polycaprolactone composite produced in a conventional fused filament fabrication equipment: Process modeling and parameters adjustment

AbstractPolymer composites with continuous fibers are expected to exhibit good mechanical performance due to orientation and high aspect ratio of fillers. Fused filament fabrication (FFF) provides an affordable method for processing these materials as products with tunable architecture. By incorporating continuous bioactive fibers coated with biodegradable polymer, the degradation rate of printed scaffolds may vary over time. As proof of concept, macroporous composites were 3D printed using continuous glass fiber‐reinforced polycaprolactone filament. Parametrization and challenges associated with printing on non‐dedicated equipment are discussed. A model describing the melt flow was employed to evaluate the velocity and shear rate profiles. Although the maximum velocity is approximately 18 mm s−1 for both neat and reinforced polymer, the obstruction caused by fibers results in higher shear rate, up to 481 s−1, higher pressure gradient, 1.95 MPa mm−1, and higher velocity gradient, conditions that limit print quality. Additionally, it was also possible to determine the shear stress experienced by the fiber bundle, 300 KPa, and the influence of different processing conditions. This investigation advances the development and understanding of manufacturing of continuous fiber‐reinforced polymers via FFF.

The Effect of Hot Forming–Quenching and Heat Treatment Processes on the Mechanical Properties of AA6016 Aluminum Alloy Sheets

This study explored the impact of Hot Forming–Quenching (HFQ) and heat treatment processes on the mechanical properties of AA6016 sheets. The experimental findings demonstrated that at high-temperature pre-straining (HT-PS) of 15%, the strength performance of the AA6016 sheet exhibited enhancement, with a progressive increase in both the heat treatment temperature and duration. Conversely, under HT-PS conditions of 3% and 7%, the heat treatment process exhibited a relatively modest impact on the mechanical properties of the AA6016 sheet. Differential scanning calorimetry (DSC) was employed to understand the influence of different process conditions on the precipitated phases. By comparing the precipitation peaks of the β″ phase at HT-PS of 3% and 15%, it was observed that the precipitation peak of the β″ phase decreased with an increase in HT-PS. This indicated that HT-PS promoted the precipitation of the β″ phase. In order to forecast the mechanical performance of the AA6016 sheets after applying various pre-straining and heat treatment parameters, two models were used: a backpropagation (BP) neural network and a genetic algorithm (GA)-BP neural network. These models were evaluated for their fitting and predictive capabilities. The research findings demonstrated that the GA-BP neural network model exhibited superior fitting and predictive accuracy compared to the BP neural network model.

Analysis of lattice deformation originated from residual stress on performance of aluminum nitride-based bulk acoustic wave resonators

With the development of MEMS technology to the nanometer scale, the influence of different process conditions on the performance of nano-devices can be calculated through the microscopic changes of materials. During the manufacturing process, the large residual stress from the film stack significantly influences the performance of devices, thereby reducing the wafer yield. Herein, we apply density functional theory to MEMS processes to reveal the intrinsic mechanism of how residual stress affects the performance of aluminum nitride-based bulk acoustic wave (BAW) resonators on an 8-inch high-resistance silicon wafer. The variation rule of physical properties of piezoelectric material aluminum nitride with different residual stresses is calculated via first-principles calculations. Through theory formula derivation, the piezoelectric-coupling constant (Kt2) of the bulk acoustic wave resonator is positively correlated with tensile residual stress, and the resonant frequency (fp, fs) is negatively correlated with tensile residual stress. The measurement results show that the average shifts of Keff2 is 0.12 % within −137 MPa and 183 Mpa residual stress, which is an excellent match with the theory prediction.

Thermodynamic modelling of mixtures of water, carbon dioxide and hydrogen at high pressure and temperature for hydrothermal CO2 reduction processes

In the context of the increasing CO2 emissions and the corresponding environmental problems, CO2 utilization processes that transform CO2 into valuable compounds rather than just capturing and storing it can contribute to the transition to a carbon-free economy, giving value to unavoidable CO2 emissions. Among the different technologies studied, hydrothermal conversion stands out by the high yields achieved in comparatively short reaction times and by the possibility to scale-up the process. The hydrothermal conversion uses CO2 dissolved in aqueous solutions as feedstock, in which bicarbonate is the reacting species. Therefore, knowledge of the equilibrium concentrations of dissolved species is of interest for the development of the process. In this work, a thermodynamic model based on the activity coefficient model developed by Pitzer, Sun and Duan model is implemented and solved. The influence of different process conditions: temperature, pressure, composition of the initial solution, on the equilibrium composition of the dissolution is analyzed with the model. Experimental results obtained in hydrothermal reduction experiments are thus interpreted with the aid of the model. It is observed that the process is favored by moderate temperatures (<500 K), high initial concentrations of sodium bicarbonate (up to 2 mol/kg) and moderate initial concentrations of sodium hydroxide (below 1.5 mol/kg).

Optimization of Multiple W1/O/W2 Emulsions Processing for Suitable Stability and Encapsulation Efficiency.

Double emulsions are a type of multiple emulsions, which can be defined as a multicompartmentalized system where the droplets are dispersed into the continuous phase containing other emulsions. Although double food-grade emulsions have been manufactured, there is a lack of scientific background related to the influence of different processing conditions. This work analyses the influence of processing variables in (W1/O/W2) double emulsions: passes through the valve homogenizer, pressure applied, lipophilic emulsifier concentration, the ratio between the continuous phase (W2) and the primary emulsion (W1/O), and the incorporation of xanthan gum (XG) as a stabilizer. The results obtained show that these emulsions can be obtained after selecting suitable processing conditions, making them easily scalable in industrial processes. In terms of droplet size distribution, the input of higher energy to the system (20 MPa) during emulsification processing led to emulsions with smaller droplet sizes (D3,2). However, more monodispersed emulsions were achieved when the lowest pressure (5 MPa) was used. As for the number of passes, the optimal (emulsions more monodispersed and smaller droplet sizes) was found around 2–3 passes, regardless of the valve homogenizer pressure. However, emulsions processed at 20 MPa involved lower encapsulation efficiency (EE) than emulsions processed at 5 MPa (87.3 ± 2.3 vs. 96.1 ± 1.8, respectively). The addition of XG led to more structured emulsions, and consequently, their kinetic stability increased. The results obtained indicated that a correct formulation of these W1/O/W2 double emulsions allowed the optimal encapsulation of both hydrophilic and lipophilic bioactive compounds. Thus, the development of food matrices, in the form of multiple emulsions, would allow the encapsulation of bioactive compounds, which would result in the development of novelty food products.

Improving Layer Adhesion of Co-Extruded Polymer Sheets by Inducing Interfacial Flow Instabilities.

Co-extrusion is commonly used to produce polymer multilayer products with different materials tailoring the property profiles. Adhesion between the individual layers is crucial to the overall performance of the final structure. Layer adhesion is determined by the compatibility of the polymers at the interface and their interaction forces, causing for example the formation of adhesive or chemical bonds or an interdiffusion layer. Additionally, the processing conditions, such as temperature, residence time, cooling rate, and interfacial shear stress, have a major influence on the interactions and hence resulting layer adhesion. Influences of temperature and residence time are already quite well studied, but influence of shear load on the formation of an adhesion layer is less explored and controversially discussed in existing literature. In this work, we investigated the influence of different processing conditions causing various shear loads on layer adhesion for a two-layer co-extruded polymer sheet using a polypropylene and polypropylene talc compound system. Therefore, we varied the flow rates and the flow geometry of the die. Under specific conditions interfacial flow instabilities are triggered that form micro layers in the transition regime between the two layers causing a major increase in layer adhesion. This structure was analyzed using confocal Raman microscopy. Making use of these interfacial flow instabilities in a controlled way enables completely new opportunities and potentials for multi-layer products.

In situ ruminal disappearance of crude protein and phytate from differently processed rapeseed meals in dairy cows.

The influence of different processing conditions of rapeseed meal on ruminal degradation of crude protein and phytate in dairy cows was investigated. Following oil extraction from the rapeseed, five residence times in the desolventizer/toaster were chosen to remove the solvent from the meal. Rapeseed cake and rapeseed meals were incubated in situ in the rumen of three fistulated dairy cows to determine ruminal degradation parameters. With increasing residence time in the desolventizer/toaster the ruminal degradation of crude protein decreased significantly for every treatment step. Ruminal phytate degradation and crude protein degradation were affected almost identically. The processing conditions of rapeseed meal have a major impact on the ruminal degradation of crude protein and phytate, indicating a potential conflict of interest regarding the production process. Large amounts of undegradable rumen protein are often intended for high-yielding dairy cows whereas a high level of ruminal degradation is preferred for phytate to increase absorption of phosphorus in the small intestine. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

On the material removal mechanism in rotary ultrasonic milling of ultralow-density silica aerogel composites

Silica aerogel composite with ultralow density is a kind of highly porous solid with excellent property of thermal conductivity. It is widely used for thermal insulation in aerospace, national defense and military industries. However, silica aerogel composites are difficult to process, due to the poor mechanical properties, low strength and high brittleness. Therefore, it is necessary to investigate the processing characteristics and material removal mechanism of silica aerogel composites. In this article, a cutting model of silica aerogel composites is established firstly and the fracture mechanism of fiber was analyzed. Then the ultrasonic milling and conventional milling experiments were performed respectively to obtain the features of machined surface. Macro morphology and surface roughness of machined surfaces in different process conditions are compared to investigate the influence of different process conditions on the processing quality. Scanning electron microscope (SEM) was used to obtain the micro morphology of processed surfaces. By comparing and analyzing the micro morphology of processed surfaces, the influence of process conditions on removal mechanism was investigated. The theoretical cutting force and experiment cutting force is compared to verify the cutting model. The results show that the burrs and pits decrease with the ultrasonic vibration amplitude, and increase with the tool diameter. Processing quality of up-milling is better than down-milling. It is indicated that shearing and pulling off are the main removal mechanism of silica aerogel composites. When the silica aerogel composites are processed by rotary ultrasonic milling and up milling, the fibers will be mainly removed by shearing mechanism and the proportion of fibers removed by shearing facture mechanism will be improved with the increase of ultrasonic amplitude.

P-061. Successful vaginal delivery in pregnant women with preeclampsia undergoing labor induction with Prostaglandin

Silica aerogel composite with ultralow density is a kind of highly porous solid with excellent property of thermal conductivity. It is widely used for thermal insulation in aerospace, national defense and military industries. However, silica aerogel composites are difficult to process, due to the poor mechanical properties, low strength and high brittleness. Therefore, it is necessary to investigate the processing characteristics and material removal mechanism of silica aerogel composites. In this article, a cutting model of silica aerogel composites is established firstly and the fracture mechanism of fiber was analyzed. Then the ultrasonic milling and conventional milling experiments were performed respectively to obtain the features of machined surface. Macro morphology and surface roughness of machined surfaces in different process conditions are compared to investigate the influence of different process conditions on the processing quality. Scanning electron microscope (SEM) was used to obtain the micro morphology of processed surfaces. By comparing and analyzing the micro morphology of processed surfaces, the influence of process conditions on removal mechanism was investigated. The theoretical cutting force and experiment cutting force is compared to verify the cutting model. The results show that the burrs and pits decrease with the ultrasonic vibration amplitude, and increase with the tool diameter. Processing quality of up-milling is better than down-milling. It is indicated that shearing and pulling off are the main removal mechanism of silica aerogel composites. When the silica aerogel composites are processed by rotary ultrasonic milling and up milling, the fibers will be mainly removed by shearing mechanism and the proportion of fibers removed by shearing facture mechanism will be improved with the increase of ultrasonic amplitude.

SY5-2. Simplified prediction criteria and management of preeclampsia for LMIC

Silica aerogel composite with ultralow density is a kind of highly porous solid with excellent property of thermal conductivity. It is widely used for thermal insulation in aerospace, national defense and military industries. However, silica aerogel composites are difficult to process, due to the poor mechanical properties, low strength and high brittleness. Therefore, it is necessary to investigate the processing characteristics and material removal mechanism of silica aerogel composites. In this article, a cutting model of silica aerogel composites is established firstly and the fracture mechanism of fiber was analyzed. Then the ultrasonic milling and conventional milling experiments were performed respectively to obtain the features of machined surface. Macro morphology and surface roughness of machined surfaces in different process conditions are compared to investigate the influence of different process conditions on the processing quality. Scanning electron microscope (SEM) was used to obtain the micro morphology of processed surfaces. By comparing and analyzing the micro morphology of processed surfaces, the influence of process conditions on removal mechanism was investigated. The theoretical cutting force and experiment cutting force is compared to verify the cutting model. The results show that the burrs and pits decrease with the ultrasonic vibration amplitude, and increase with the tool diameter. Processing quality of up-milling is better than down-milling. It is indicated that shearing and pulling off are the main removal mechanism of silica aerogel composites. When the silica aerogel composites are processed by rotary ultrasonic milling and up milling, the fibers will be mainly removed by shearing mechanism and the proportion of fibers removed by shearing facture mechanism will be improved with the increase of ultrasonic amplitude.

P-057. Preeclampsia prediction based on urine peptidome study

Silica aerogel composite with ultralow density is a kind of highly porous solid with excellent property of thermal conductivity. It is widely used for thermal insulation in aerospace, national defense and military industries. However, silica aerogel composites are difficult to process, due to the poor mechanical properties, low strength and high brittleness. Therefore, it is necessary to investigate the processing characteristics and material removal mechanism of silica aerogel composites. In this article, a cutting model of silica aerogel composites is established firstly and the fracture mechanism of fiber was analyzed. Then the ultrasonic milling and conventional milling experiments were performed respectively to obtain the features of machined surface. Macro morphology and surface roughness of machined surfaces in different process conditions are compared to investigate the influence of different process conditions on the processing quality. Scanning electron microscope (SEM) was used to obtain the micro morphology of processed surfaces. By comparing and analyzing the micro morphology of processed surfaces, the influence of process conditions on removal mechanism was investigated. The theoretical cutting force and experiment cutting force is compared to verify the cutting model. The results show that the burrs and pits decrease with the ultrasonic vibration amplitude, and increase with the tool diameter. Processing quality of up-milling is better than down-milling. It is indicated that shearing and pulling off are the main removal mechanism of silica aerogel composites. When the silica aerogel composites are processed by rotary ultrasonic milling and up milling, the fibers will be mainly removed by shearing mechanism and the proportion of fibers removed by shearing facture mechanism will be improved with the increase of ultrasonic amplitude.

Investigation on the Distribution of Yimin Lignite Pyrolysis Products and the Stability of its Char.

This paper introduces the utilization of lignite in China and abroad and studies the influence of different process conditions on the pyrolysis products of lignite. The effects of pyrolysis temperature, residence time, and heating rate on the yield and stability of pyrolysis products were studied by standard lattice low-temperature distillation of coal. The results showed that the final pyrolysis temperature of lignite increases gradually, which is a key factor affecting the pyrolysis performance of lignite. At the same time, the combustible gas yield and tar yield were also significantly improved. Semichar yield and semichar volatile content showed a downward trend. From the range of pyrolysis products, the heating rate also has an important influence on the pyrolysis performance of lignite. Through the thermal stability test of lignite, it is concluded that the particle size distribution of carbon black products is not significantly different, and most of the coal particles are mainly distributed in the range of more than 6 mm.

Directions of Changes in the Content of Selected Macro- and Micronutrients of Kale, Rutabaga, Green and Purple Cauliflower Due to Hydrothermal Treatment

Little is still known about macro- and micronutrients in processed selected Brassica vegetables such as purple and green cauliflower, rutabaga and kale. This study evaluates the influence of different processing conditions (blanching and boiling) on the stability of selected macro- and micronutrients in the aforementioned vegetables. Results indicated that blanching and boiling affect the mineral content of Brassica vegetables. Of the examined Brassica vegetables, the largest losses were found for potassium and iron (on average by 39.72%).

The preparation and performance of polyaniline coated polyester fabrics

In this experiment, the polyaniline coated fabrics were produced using aniline as the monomer by in-situ polymerization, p-toluenesulfonic acid as the doping agent and ammonium persulfate as the oxidant on the polyester fabric. The influence of different process conditions on the dielectric properties of the polyaniline coated fabric was explored. The fastness to rubbing of the coated fabrics was tested. The results show that the concentration of aniline and the oxidant both influence the dielectric properties of the fabrics. An appropriate aniline concentration is beneficial to increase the output of the polyaniline and reduce sudden and violent polymerization. A suitable oxidant concentration is beneficial to form polyaniline with a complete structure, reducing the occurrence of peroxide. When the aniline concentration was 0.4 mol/L and the oxidant concentration was 0.4 ∼ 0.5 mol/L, the polarizing ability, loss ability and absorbing-attenuation ability of the fabrics to electromagnetic waves are all stronger. The dielectric properties of the obtained polyaniline coated fabrics varied corresponding to different types of dopants and doping levels. Compared to glacial acetic acid, hydrochloric acid and nitric acid, the dielectric properties of the prepared coated fabric were optimal when using p-toluenesulfonic acid as the dopant. When the concentration of the p-toluenesulfonic acid was 0.2 mol/L, the polarizing, loss and absorbing-attenuation abilities of the fabrics to electromagnetic waves are all stronger.

Industrial Strategies to Reduce Acrylamide Formation in Californian-Style Green Ripe Olives.

Acrylamide, a compound identified as a probable carcinogen, is generated during the sterilization phase employed during the processing of Californian-style green ripe olives. It is possible to reduce the content of this toxic compound by applying different strategies during the processing of green ripe olives. The influence of different processing conditions on acrylamide content was studied in three olives varieties (“Manzanilla de Sevilla”, “Hojiblanca”, and “Manzanilla Cacereña”). Olives harvested during the yellow–green stage presented higher acrylamide concentrations than green olives. A significant reduction in acrylamide content was observed when olives were washed with water at 25 °C for 45 min (25% reduction) and for 2 h (45% reduction) prior to lye treatment. Stone olives had 21–26% higher acrylamide levels than pitted olives and 42–50% higher levels than sliced olives in the three studied varieties. When calcium chloride (CaCl2) was added to the brine and brine sodium chloride (NaCl) increased from 2% to 4%, olives presented higher concentrations of this contaminant. The addition of additives did not affect acrylamide levels when olives were canned without brine. Results from this study are very useful for the table olive industry to identify critical points in the production of Californian-style green ripe olives, thus, helping to control acrylamide formation in this foodstuff.

Finite Element Analysis of Extrusion Process for Magnesium Alloy Internal Threads with Electromagnetic Induction-Assisted Heating and Thread Performance Research.

The casting magnesium alloy AZ91D cannot be extruded at room temperature. This paper presents a process for extruding internal threads using AZ91D heated by electromagnetic induction. The feasibility of the process is verified by finite element simulation and experiments. Using DEFORM-3D to simulate the process of extruding a M12 × 1.25 mm threaded hole by electromagnetic induction-assisted heating, the equivalent stress-strain and material flow law in the process of thread deformation was analyzed and verified by experiments. Three parameters—hole diameter, machine speed and heating temperature—were considered to study the influence of different process conditions on the forming torque. The results show that a heating temperature above 523 K can improve the plasticity of AZ91D. The hole diameter has an important influence on the forming torque. The forming process is not suitable for high-speed machining. The surface metal of the thread formed by this process has a strong deformation layer, which can improve the strength and hardness of the thread.

Numerical Simulation of Mixing Characteristics in the Eccentric Rotor Extruder with Different Process Conditions and Structural Parameters

Numerical simulation was performed with the computational fluid dynamics analysis software POLYFLOW to investigate the influence of different process conditions and structural parameters on mixing characteristics of the eccentric rotor extruder. The intensity of shear and elongational flow strengthened when the rotational speed increased, but the time for material to stay in the extruder will be reduced. At the same time, the increase of radius and eccentricity could effectively promote the mixing performance. On the contrary, the mixing capacity reduced with the increase of the pitch. The results can be useful to optimize the structure design and guide production.

Study on biochemical degumming process of mulberry fiber,part 1:single factor analysis

ABSTRACT Mulberry fiber is a new natural fiber. More and more attentions are paid to mulberry because of its good properties. The traditional chemical degumming method is liable to cause environmental pollution. This subject adopts the method of biochemical degumming technology to obtain mulberry fibers with certain spinnable properties. The degumming process of mulberry bark is studied on the basis of knowing the chemical composition and percentage content of the material composition of the raw material of mulberry bark, and the influence of different process conditions and parameters on the degumming effect is analyzed. Through single factor experiment and analysis of results, the optimized process parameters of biochemical combined degumming are as follows: the temperature and concentration of pickling acid pretreatment are 60°C and 2.5 g/L, respectively. The concentration, duration of action, and bath ratio of alkaline pectinase are 47 g/L, 8 h, and 1:20, respectively. The concentration and action time of sodium hydroxide in alkali boiling are: 10 g/L, 3 h. The concentration, duration of action, and bath ratio of xylanase are 10 g/L, 4 h, 1:20, respectively. The optimization process parameters obtained above lay the foundation for further orthogonal experiments to obtain the optimal degumming process.

Germanium and Indium Recovery from Zinc Metallurgy by-Products—Dross Leaching in Sulphuric and Oxalic Acids

Leaching of the dross containing 28.7% Sn, 18.0 Pb, 10.6% Cu, 8.9% Ge, 8.1% Zn, and 2.7% In in sulphuric and oxalic acid solution was investigated. The dross was obtained from thermal oxidation of by-product alloy generated during a New Jersey (NJ) zinc rectification process. The influence of different process conditions (temperature, time, acid concentration, and solid to liquid ratio) on leaching yield of the main components was determined. Additionally, the impact of oxidant (hydrogen peroxide, sodium hypochlorite, manganese (IV) oxide) addition on leachabilities was investigated. Germanium leaching yields exceeding 80% were observed for both sulphuric and oxalic acid solutions. Indium leachability in H2C2O4(aq) was found at the level of 20%, while in H2SO4(aq), it strongly depends on process temperature, and reached 80% at 80 °C.

Phenolics, Tocopherols, and Volatiles Changes During Virgin Pistachio Oil Processing Under Different Technological Conditions

The present work aims to study the influence of different processing conditions, including temperature, roasting, the use of whole nuts, pressure (nozzle size) and speed of the screw‐press extraction process, on the minor components, mainly tocopherols, phenolics, and volatile components, contained in virgin pistachio oils (VPO) and their corresponding partially defatted residual cakes. An important increase in total polar phenolic (TPP) is observed in VPO processed at a temperature above 60 °C (e.g., 16.7–65.3 and 76.4 mg kg−1 at 130 °C and roasting conditions). TPP and the corresponding antioxidant activity also increase when a smaller nozzle diameter (3 mm) is used (16.7–35.4 mg kg−1; DPPH increases 36%), but no differences are observed when changing the screw speed. It is remarkable that the use of the whole pistachio (with its shell) helps to greatly enrich the oil in aromatic volatile compounds by up to 135%, with terpenes being the main family (e.g., 38.6–90.9 mg kg−1). Phenolic compounds and their antioxidant activity are higher in the residual cake when a higher processing temperature is used, for example, from 7260 to 12 250 mg kg−1 (at 40 and 130 °C, respectively). This result indicates their potential use as functional ingredients in food formulations.Practical Applications: The edible oil market is expanding and creating new products, where nut oils are gaining space in the preferences of consumers. In this sense, the study of the effect of different oil extraction conditions on the minor composition may help to produce VPOs with a higher bioactive compound content and/or with desired organoleptic characteristics.Virgin nut oils are minimally processed foods characterized by their typical aroma, taste, and minor bioactive compounds depending on the extraction and processing methods employed. Different technological conditions are studied using a screw‐press expeller to produce added value pistachio virgin oils and their residual cakes.