Pressure Bar Research Articles

Rational Matching of Metal-Organic Frameworks and Polymers in Mixed Matrix Membranes for Efficient Propylene/Propane Separation.

The exploitation of high-performance membranes selective for propylene is important for developing energy-efficient propylene/propane (C3H6/C3H8) separation technologies. Although metal-organic frameworks with a molecular sieving property have been considered promising filler materials in mixed-matrix membranes (MMMs), their use in practical applications has been challenging due to a lack of interface compatibility. Herein, we adopted a surface coordination strategy that involved rationally utilizing carboxyl-functionalized PIM-1 (cPIM) and ZIF-8 to prepare a mixed-matrix membrane for efficient propylene/propane separation. The interfacial coordination between the polymer and the MOF improves their compatibility and eliminates the need for additional modification of the MOF, thereby maximizing the inherent screening performance of the MOF filler. Additionally, the utilization of porous PIM-1 guaranteed the high permeability of the MMMs. The obtained MMMs exhibited excellent separation performance. The 30 wt% ZIF-8/cPIM-1 membrane performed the best, exhibiting a high C3H6 permeability of 1023 Barrer with a moderate C3H6/C3H8 selectivity of 13.97 under 2 bars of pressure. This work presents a method that can feasibly be used for the preparation of defect-free MOF-based MMMs for specific gas separations.

Propylene carbonate synthesis routes using CO2: DFT and thermodynamic analysis

Propylene carbonate (PC) is utilized to improve performance and stability in lithium-ion batteries as an electrolyte component and as a high-performance solvent in paints, varnishes, and adhesives. It is a versatile chemical used in many different industries. It also functions as a plasticizer in polymers and a solvent in pharmaceutical and cosmetic formulations. In the current work, chemical equilibrium analyses of a number of potential processes involved in the synthesis of PC were conducted. To examine the thermodynamic viability of all five approaches, the fluctuation of ΔGmo with temperature for the key processes of PC synthesis was investigated in a specific temperature range of 25 °C-180 °C and at 1 bar and 60 bar pressures. The heat capacity values were estimated using the Rozicka-Domalski method. Benson Group-Increment Theory (BGIT) was used to evaluate the unknown ΔfH for a molecule. By examining the impact of temperature (25 °C-180 °C) and pressure (0–100 bars) on chemical equilibrium constant and equilibrium conversion of reactants, the main reactions of PC synthesis pathways were compared. It was discovered that the one-pot synthesis route and the o-chloropropanol and CO2 approach were superior. The DFT calculations were performed to study the energy changes taking place to convert propylene, glycerol, and propylene glycol (PG) into PC. Both thermodynamic and DFT calculations proved that the PG and urea route is the least favorable for synthesizing PC.

Superhydrophobic microporous membrane based on modified microfibrillated cellulose framework for efficient oil-water separation

The preparation of stable and efficient cellulose-based oil/water separation membranes is of great significance in solving the problem of industrial oily wastewater. Herein, rod-like hydroxyapatite (HAP) modified microfibrillated celluloses (MFCs) are used to form the fibrous framework to produce a microporous PDMS-MFC-HAP membrane. The membrane shows good superhydrophobicity with a water contact angle of 151.6°. It exhibits the oil-water separation performance for various water-in-oil emulsions. The separation flux of the membrane is up to 3665.3 L·m−2·h−1·bar−1 under 0.5 bar pressure with a separation efficiency of over 99.6 %. The PDMS-MFC-HAP membrane could maintain a high separation efficiency of 98.6 % after 20 cycles. This study provides a simple and effective method to fabricate cellulose-based superhydrophobic membranes, which have a greater potential to achieve oil-water separation for oily wastewater treatment with high efficiency.

HYDROGEN GAS RECOVERY THROUGH THE PERMEATION MEMBRANE BASED BIMETALLIC PALLADIUM ALLOY

Generally, the H2 gas produced from the industrial processes is not in a pure state but is mixed with other compounds. For example, the off-gas produced in the oil refinery process still contains CH4, H2, and other gases. Thus, the process of separating as well as recovering the valuable H2 gas from other gas compounds is of essential process. Currently, the H2 separation process is being developed with relatively low costs with good efficiency, namely using the permeation membranes separation process, in which the compounds with high permeability tends to be more easily separated. Here we report the hydrogen recovery process from the mixed H2/N2 off-gas contains 61 % hydrogen and 39% balancing nitrogen, by using the bimetallic Pd-Ag membrane, where the effect of the gas feed pressure (1 and 2 bar) and operating temperature (373.15, 423.15, 473.15, and 523.15, 573.15 K) on the resulting permeate flux is comprehensively studied. We found that the flux and permeability increased with the increase in the gas feed pressure and temperature. Under the same gas temperature of 373.15 K, the permeation flux at the 2 bar gas feed pressure was found to be 2.047 mol.s-1.m-2, which was 166% greater than that of 1 bar pressure, i.e. 1.204 mol.s-1.m-2. Meanwhile, under the same gas feed pressure of 2 bar, the permeation flux at the operating temperature of 573.15 K was found to be 2.103 mol.s-1.m-2, which is 104,9% greater than that of 373.15 K operating temperature, i.e. 2.047 mol.s-1.m-2. These findings suggest the breakthrough advantages of the Pd-Ag alloy membrane for its high hydrogen permeability at low pressure.

Dynamic mechanical properties and uni-axial constitutive model of S30408 stainless steel

This paper investigates its mechanical properties at different strain rates and the uni-axial constitutive model of S30408 (S30408 known as 1.4301 in EN10088:1, 304 in ASTM standard) stainless steel. Firstly, the tensile and compressive mechanical properties of S30408 stainless steel were tested at four strain rates (0.001 s−1, 1000 s−1, 3000 s−1, 5000 s−1) by performing quasi-static tests as well as split Hopkinson tension bar (SHTB) and split Hopkinson pressure bar (SHPB) tests. Based on the tests, the stress-strain curves of S30408 stainless steel under tensile and compressive conditions at different strain rates were obtained. The results show that S30408 stainless steel revealed a significant strain rate strengthening effect, and there were some differences in the mechanical properties of S30408 stainless steel in tension and compression under different strain rates. Then based on these test results, a modified Johnson–Cook model was established under tensile and compression conditions. The accuracy of the proposed modified Johnson-Cook model was verified by the finite element software LS-DYNA. The modified model can provide a reference for the study of mechanical properties and computational simulation of S30408 stainless steel under high strain rate conditions such as impact and blast load.

Evaluation of Freezanz automated misting system against mosquitoes

Automated misting systems are a convenient way for homeowners or small businesses to control adult mosquitoes. One such system was presented to the Anastasia Mosquito Control District (AMCD) for evaluation to control caged Aedes aegypti. The system consisted of 3 spray tanks, 2 pumps, water level sensors, and flow meters, and was controlled through an Android tablet loaded with dedicated control software. The evaluation of the system included calibration tests, droplet characterization, spray dispersion in the open field, and effectiveness testing using bio-assay cages for mortality assessment. For these tests, a loop of 14 nozzles 4 m apart was connected and held at 1 m height utilizing a total of 120 m tube. All nozzles were arranged in a 16 × 12 m rectangle laid in the East-West direction. Water was sprayed for calibration and droplet size measurements at pressures of 13.0, 15.5, and 18 bar; water and 10 % red dye solution for spray dispersion at 18 bar pressure, and 0.17 % solution of equalizer 20–20 was sprayed at 18 bar pressure for mortality tests. All 3 replicated tests were conducted in the morning between 9:00 and 11:30am. During this time, temperature ranged from 21 to 26 °C, relative humidity from 54 to 95%, and wind speed from 0 – 2 km/hr.The combined flow rate from all 14 nozzles was significantly affected by pressure and was in agreement with the machine-calculated flow rate. There was a similar flow rate from all nozzles, indicated by a standard error of 0.82 mL/min. The droplet characteristics represented by DV0.1, DV0.5, and DV0.9 were not affected by nozzles but decreased with an increase in pressure as expected. The percentage of coverage on the cards, an indicator of spray dispersion, ranged from 20 -100%, and it was found to increase in the direction of the wind. Mosquito mortality showed a similar trend of increasing in the wind direction and ranged from 30 to 100 %. There was no effect of the location of cages on mosquito mortality. These results indicate that the effectiveness of this spray depends upon wind direction. The results, however, may be different when there is no wind, which may be the case during the times these applications are made.

Characterization of fatigue behavior of 3D printed pneumatic fluidic elastomer actuators

Soft robots have gained significant interest due to their high flexibility and adaptability to various working conditions. Recent advancements in engineering and innovative materials have enabled the design and production of sophisticated soft robotic systems with enhanced capabilities. This study aims to evaluate the fatigue behavior of bellow-type pneumatic soft actuators fabricated through fused filament fabrication (FFF) using thermoplastic polyurethane (TPU), compared to silicone rubber cast actuators. The actuators were equipped with resistive flex sensors to monitor bending motion, and fatigue tests were performed with cycles of inflation and deflation until failure. Results showed that 3D printed TPU actuators could withstand a significant number of cycles before failure, with an average of 6410 cycles at 3 bar pressure, compared to 3439 cycles at 1 bar pressure for the silicone actuators. The study identified a set of fabrication parameters that positively affect the durability of TPU actuators, providing valuable insights for replicating these results. Additionally, the study established a plausible range of utilization for 3D-printed FFF actuators in terms of the number of cycles they can endure, offering critical data for engineers and designers to make informed decisions about the design and application of these actuators in various practical scenarios. The findings demonstrate the potential of FFF for producing durable, long-lasting pneumatic soft actuators.

Transient analysis of a near-zero energy building with green hydrogen production integrated with energy storage systems

The current study highlights the potential of hybrid renewable energy systems in mitigating CO2 emissions for a near-zero energy building. A Python-based controller is used to manage the state of charge (SoC) of the lithium-ion battery. Two buildings are considered in the study. Once the SoC in the first building reaches 75 %, the system prevents overcharging and redirects the green electricity towards the hybrid system for hydrogen production. To compare the role of a hybrid system in which a fuel cell is used to supply the required energy for electric load and electrolyzer demand, a diesel generator is considered for the same energy demands. The hybrid system achieves a 56.14 % reduction in diesel fuel consumption, leading to an annual decrease of 33.860 tons of CO2 emissions. Economic analysis reveals that while the cost of the diesel mode is calculated to be 96 % higher than the hybrid mode, the CO2 emissions in the hybrid mode will be 56.14 % lower than the full diesel mode. Additionally, the system's total annual hydrogen production is 7582.74 kg, with a maximum production rate of 15.52 m³/hr at 1.3 bar pressure. Despite higher initial costs, hybrid systems effectively address the challenge of CO2 emissions compared to conventional systems. The results underscore the necessity of hybrid systems for achieving significant reductions in fossil fuel consumption, presenting a sustainable solution for future energy needs.

The impact of aging and thickness on flexural strength of various zirconia ceramics

BackgroundEffects of the aging process on the flexural strength of Y-TZP and different Y-PSZ ceramics of different thicknesses were investigated.Methods300 disc-shaped samples (12 mm diameter, 0.8 and 1.5 mm thicknesses) were made from 5 different zirconia materials 3Y-TZP LA, 4Y-PSZ, 5Y-PSZ, 3 + 5Y-PSZ and 4 + 5Y-PSZ. Experimental groups were artificially aged in an autoclave at 134 °C, 2 bar pressure for 1 and 5 h; control groups were not subjected to any treatment. Microstructural analysis was conducted using Scanning Electron Microscopy, and X-Ray Diffraction analysis determined the crystalline phase content. The impact of aging on flexural strength was investigated with the use of the biaxial flexural strength test. Data were analyzed using three-way ANOVA tests with a significance level of p < 0.05, applying Bonferroni correction for multiple comparisons.ResultsStatistically significant differences in flexural strength were observed among the materials and the material thicknesses (p < 0.05), while there were no significant differences among the aging times (p > 0.05). The highest mean flexural strength values were recorded in the case of the 3 Y-TZP-1.5 mm–5 h group (744.1 ± 61.2 MPa), which was attributed to phase-transformation toughening. The lowest values were observed in the case of the 5 Y-PSZ-1.5 mm–5 h (338.3 ± 34.8 MPa) group.ConclusionsBoth material type and thickness significantly affect the flexural strength of zirconia ceramics, whereas aging time does not; thus, material selection and thickness are crucial considerations for clinicians.

CO2 Sorption on Ti-, Zr-, and [Ti,Zr]-Pillared Montmorillonites.

Montmorillonite is a layered clay mineral whose modification by pillaring, i.e., insertion of oxide nanoclusters between the layers, yields porous materials of great potential in sorption and catalysis. In the present study, an unrefined industrial bentonite from Kopernica (Slovakia), containing ca. 70% of montmorillonite, was used for the preparation of Ti-, Zr-, and mixed [Ti,Zr]-pillared clay sorbents. The pillared samples were characterized with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and N2 adsorption at -196 °C and tested for the capacity of CO2 sorption at 0 °C and 1 bar pressure. The experiments revealed that pillared samples sorbed at least four times more CO2 than the parent bentonite. Of the materials tested, the sample pillared with mixed [Ti,Zr] oxide props showed the best performance, which was attributed to its superior microporosity. The results of CO2 adsorption demonstrated that the cost-effective use of crude industrial bentonite as the sorbent precursor is a viable synthesis option. In another experiment, all pillared montmorillonites were subjected to 24 h exposure at room temperature to a flow of dry CO2 and then tested using simultaneous thermal analysis (STA) and the mass spectrometry (MS) analysis of the evolving gases (STA/QMS). It was found that interaction with dry CO2 reduces the amount of bound carbon dioxide and affects the processes of dehydration, dehydroxylation, and the mode of CO2 binding in the pillared structure.

Highly microporous activated carbons synthesized from sacrificial templating of melamine for CH4 and H2 storages and CH4/H2 adsorptive separation

Achieving carbon neutrality necessitates advancements in adsorbent-based gas storage technologies, particularly for maximizing the utilization of natural gas (CH4) and hydrogen (H2) as sustainable energy sources. Activated carbons, characterized by their high surface area, stability, and cost-effectiveness, emerge as promising candidates for CH4 and H2 storage applications. Here, we report highly microporous activated carbons prepared using sacrificial templating of melamine followed by Cs+ ion activation. The resulting activated carbon demonstrates exceptional microporous characteristics, boasting a significantly high micropore surface area (2311 m2/g) and micropore volume (1.070 cm3 g−1). These structural attributes translate into impressive CH4 (11.92 mmol/g at 298 K and 70 bar) and H2 (2.74 mmol/g at 298 K and 70 bar) storage capacities, underscoring its potential as a viable ambient temperature gas storage material. Furthermore, our evaluation extends to the performance of the activated carbon for adsorptive CH4/H2 separation. The activated carbon exhibits a notable CH4 working capacity (3.13 mmol/g at 298 K, 1–10 bar pressure swing) coupled with a moderate Ideal Adsorbed Solution Theory (IAST) selectivity (25). These findings highlight the suitability of the activated carbon for both CH4 and H2 storage applications, as well as the separation of H2 from CH4.

Graphene pillared - Porous graphene framework; structural analysis and gas storage capacities

Porous graphene structures continue to attract attention with their increasingly superior properties. Especially through carbon-based porous structures in a framework form have found applications in various fields such as gas storage. In this study, graphene fragments were utilized as pillars between graphene layers to create a novel framework structure, and geometry optimization was performed under different external pressures. Adsorptions of hydrogen, carbon dioxide, and methane gases, which need to be controlled for combating global warming, were investigated for the optimized structure. It is found that the structure which withstand deformations up to 5 GPa of external pressure could store 2.005 wt % hydrogen hydrogen at room temperature and 100 bar pressure. Moreover, capable to adsorb 6.426 and 8.776 mmol/g carbon dioxide and methane at room temperature and 1 bar pressure, respectively. In conclusion, alongside other potential applications like electrical and energy storage, its usability as a gas adsorbent for combating global warming have a great potential.

Utilizing Supercritical CO2 for Bee Brood Oil Extraction and Analysis of Its Chemical Properties.

To obtain oil from bee brood, which was dried using a tray drying method, this study used the supercritical CO2 extraction method. Extraction occurred at temperatures between 40-60 °C and low pressures of 180-220 bar for 1.5 h, with a high pressure of 600 bar for 1 h. The study investigated both the yield and chemical properties of the extracted bee brood oils. Supercritical CO2 extraction of tray-dried bee brood at 600 bar pressure demonstrated higher oil extraction efficiency compared to lower pressures (180-220 bar). At temperatures of 40-60 °C, total phenolic compounds increased while total flavonoids decreased. The extracted oil exhibited antioxidant activity, primarily due to quercetin. Despite decreased acid, iodine, and saponification values, peroxide value slightly increased but remained below 12 meqO2/kg of oil. The make-up of the fatty acids changed. At 600 bar, palmitic and oleic acids were the most common, while myristic, linoleic, and docosadienoic acids decreased. At 600 bar, eicosadienoic acid was absent. The defatted bee brood retained significant essential and non-essential amino acids, indicating its potential for further development as a protein source.

3D-printed β-TCP/Ti6Al4V composite scaffolds for bone regeneration: Process parameter optimization and evaluation

A β-TCP/Ti6Al4V composite scaffold with interconnected macro porous architecture was fabricated using Direct Ink Writing (DIW). Pluronic F-127 and de-ionized water was used as binder and solvent for ink preparation. The present work was carried out to study the rheological behavior of the composite bioceramic ink and to investigate DIW process parameters such as Ti6Al4V proportion, infill percentage and extrusion pressure. The Box-Behnken response surface methodology, ANOVA, sensitivity, desirability approach are used for the experimental, statistical and numerical optimization of the parameters suitable for DIW. The output responses such as dimensional error of the fabricated scaffold from the original dimensions and compressive strength are considered for multi-objective optimization. The result defined that the optimal values are solid loading 55 %v/v (40 %v/v of β-TCP, 15 %v/v of Ti6Al4V) and 45 %v/v of Pluronic gel, 98 % infill rate and 6.36 bar pressure. The dimensional error and compressive strength of the scaffold printed at the optimized conditions are found as 1.88 % and 19 MPa with macro and micro pores suitable for bone regeneration with satisfactory biocompatibility assed via MTT assay.

Developing Hyperpolarized Butane Gas for Ventilation Lung Imaging.

NMR hyperpolarization dramatically improves the detection sensitivity of magnetic resonance through the increase in nuclear spin polarization. Because of the sensitivity increase by several orders of magnitude, additional applications have been unlocked, including imaging of gases in physiologically relevant conditions. Hyperpolarized 129Xe gas recently received FDA approval as the first inhalable gaseous MRI contrast agent for clinical functional lung imaging of a wide range of pulmonary diseases. However, production and utilization of hyperpolarized 129Xe gas faces a number of translational challenges including the high cost and complexity of contrast agent production and imaging using proton-only (i.e., conventional) clinical MRI scanners, which are typically not suited to scan 129Xe nuclei. As a solution to circumvent the translational challenges of hyperpolarized 129Xe, we have recently demonstrated the feasibility of a simple and cheap process for production of proton-hyperpolarized propane gas contrast agent using ultralow-cost disposable production equipment and demonstrated the feasibility of lung ventilation imaging using hyperpolarized propane gas in excised pig lungs. However, previous pilot studies have concluded that the hyperpolarized state of propane gas decays very fast with an exponential decay T 1 constant of ∼0.8 s at 1 bar (physiologically relevant pressure); moreover, the previously reported production rates were too slow for potential clinical utilization. Here, we investigate the feasibility of high-capacity production of hyperpolarized butane gas via heterogeneous parahydrogen-induced polarization using Rh nanoparticle-based catalyst utilizing butene gas as a precursor for parahydrogen pairwise addition. We demonstrate a remarkable result: the lifetime of the hyperpolarized state can be nearly doubled compared to that of propane (T 1 of ∼1.6 s and long-lived spin-state T S of ∼3.8 s at clinically relevant 1 bar pressure). Moreover, we demonstrate a production speed of up to 0.7 standard liters of hyperpolarized gas per second. These two synergistic developments pave the way to biomedical utilization of proton-hyperpolarized gas media for ventilation imaging. Indeed, here we demonstrate the feasibility of phantom imaging of hyperpolarized butane gas in Tedlar bags and also the feasibility of subsecond 2D ventilation gas imaging in excised rabbit lungs with 1.6 × 1.6 mm2 in-plane resolution using a clinical MRI scanner. The demonstrated results have the potential to revolutionize functional pulmonary imaging with a simple and inexpensive on-demand production of proton-hyperpolarized gas contrast media, followed by visualization on virtually any MRI scanner, including emerging bedside low-field MRI scanner technology.

Energy and exergy analysis of an innovative solar system for hydrothermal carbonization process using photovoltaic solar panels

Using renewable energy is a solution to combat environmental problems; in this context, hydrothermal carbonization is an excellent method for converting biomass into solid fuels. However, this process is energy-intensive. Systems utilizing parabolic trough solar collectors proposed in the literature present some limitations and challenges. Therefore, to overcome this issue, a novel conception combining photovoltaic solar panels and a batch reactor with a heating collar has been proposed. It was experimentally investigated and subjected to energy and exergy analyses. The experimental results showed that subcritical conditions (220 °C temperature and 40 bar pressure) were achieved. The chemical exergy of the biomass increased from 19.89 MJ/kg to 29.2 MJ/kg for the hydrochar. Due to dehydration and decarboxylation, the O/C and H/C atomic ratios decreased over time, and the hydrochar properties approximated lignite. The solar panel system achieved average energy and exergy efficiencies of 14 % and 15 %, respectively, with high thermal exergy destruction of 825.94 kWh under higher wind speeds and cell temperatures, resulting in a total entropy of 1.4 kW/K. The system's Improvement Potential ranged from 15 kW to 23 kW. The results demonstrate the feasibility of this innovative system to achieve the necessary conditions for HTC in an environmentally friendly manner.

Alkaline pretreatment of Durio sp. residual biomass enhances cellulose accessibility for efficient bioethanol production

The reliance on fossil fuels for energy generation has led to significant environmental, social, and economic challenges, necessitating the exploration of sustainable alternatives. Bioethanol, derived from renewable sources such as agricultural waste, presents a promising substitute. This study investigates the potential of durian skin, an abundant agricultural byproduct, as a raw material for bioethanol production. Alkaline pretreatment using NaOH significantly altered the chemical composition and structural properties of durian skin, increasing cellulose content and removing lignin. The cellulose content of the outer durian skin (ODS) and deep durian skin (DDS) increased by 57.53% and 59.28%, respectively, after pretreatment. The X-ray diffraction and Fourier transform infrared spectroscopy of cellulose and lignin provide significant information. Using 30 FPU enzymes to load the substrate results in DDS producing 126 g/L of glucose and 42.8 g/L of ethanol. The optimal conditions are 15% NaOH pretreatment, 150 °C, 4 bars pressure, and 90 min. The study demonstrates the economic viability and environmental benefits of utilising durian skin for bioethanol production, offering insights into sustainable energy sources and waste valorisation. These findings contribute to the global shift towards renewable energy and highlight the importance of pretreatment in enhancing bioethanol production efficiency from agricultural biomass waste.

Modelling of JP-8 distributed combustion using a HyChem mechanism under gas turbine conditions

The critical advantages of liquid fuels in aviation over alternative energy carriers imply their dominance in the upcoming decades. The Mixture Temperature Controlled (MTC) combustion concept allows spatially homogeneous, efficient burning (distributed combustion) with low pollutant emission. MTC combustion of jet fuel JP-8 was investigated in an atmospheric burner, and the measured pollutant concentrations in the flue gas were reproduced using the Hybrid Chemistry (HyChem) approach employing Perfectly Stirred Reactor simulations. Using this robust approach comes with losing spatiotemporal characteristics if the mixture homogeneity assumption is globally valid. The effect of residence time and pressure under typical gas turbine operating conditions was investigated. Stable combustion was present above 3 ms residence time at pressures up the 60 bar, which was the upper limit of the investigated regime, while the lower residence time limit of stable combustion was 0.3 ms. The residence time interval of stable operation could be extended by applying flue gas recirculation. NO emission can be reduced by increasing the operating pressure, while the N2O production is dominant only up to 20 bar and in the 10–100 ms residence time range. CO emission vanishes above 10 ms residence time. Ultra-low emission operation requires >20 bar pressure and 10 ms residence time with distributed combustion, requiring larger combustion chambers for future jet engines.

Enhanced recovery of R-phycoerythrin using recombination cell-assisted pressurized fluid extraction: yield, characterization, and antioxidant evaluation

The recovery of phycobiliproteins, with an emphasis on R-phycoerythrin (R-PE), from Solieria filiformis macroalgae was investigated in the current study. This is accomplished using an environmentally friendly method known as pressurized fluid extraction. Phycobiliprotein production was analyzed over time, considering four different parameters: i) solvents (ultrapure water and phosphate buffer), ii) macroalgae particle sizes, iii) stirring, and iv) pressure of 200 to 800 bar. Notably, the highest R-PE yield reached an impressive 22.53 mg/g dry biomass. The best extraction conditions were identified as a macerated structure, employing a combination of 500 bar pressure and agitation facilitated by a recombination cell. R-phycocyanin (R-PC) was also extracted with a 3.70 mg/g yield. Two distinct extracts, crude and precipitate, underwent comprehensive characterization. Extracted R-PE exhibited an α-helix structure (80.51–90.39 %), suggesting the existence of other proteins in both extracts. Three different subunits, α (15 kDa), β (21 kDa), and γ (29 kDa), were segregated under SDS-PAGE. Moreover, both extracts demonstrated antioxidant capacity, achieving a 99.55 % reduction in 2,2-diphenyl-1-picryl-hydrazil (DPPH) radicals and a 13.94 % chelation of ferrous ions. This study reports the extraction of biomolecules using the recombination cell for the first time in the literature, proving an appealing alternative for non-aggressive extraction with inherent biological activity. These findings underscore the potential applications of these extracted phycobiliproteins in various fields, including biotechnology and health.

An experimental study on filling of gaps and void pockets during vacuum-bag-only consolidation of fiber placed preforms

Gaps and void pockets are inevitably present in tailored thermoplastic composite preforms manufactured via automated fiber placement (AFP). Filling these gaps and voids can be challenging during the consolidation due to the high viscosity of thermoplastic composites, especially in the case of vacuum-bag-only (VBO) consolidation, where the applied pressure is limited. Therefore, the current work investigates whether one bar pressure is sufficient to fill the gaps and voids during VBO consolidation. For this purpose, two experiments are performed. First, a hot plate setup is built and used to capture the real-time gap-filling behavior during the VBO consolidation. Second, VBO consolidation of tailored preforms is performed to study the filling of ply-drop induced void pockets. Here, the tailored preform consists of plies of different orientations dropped at different locations to verify if one bar pressure available during the VBO process is sufficient to fill the void pockets. The results from both experiments answered the main question that one bar pressure is sufficient for filling the gaps and void pockets for the given material systems, and further, it was confirmed that the transverse squeeze flow was dominant in filling gaps. However, in the case of fillings of ply-drop induced void pockets, the orientation of the dropped ply and covering plies majorly dictated the filling behavior.