Separation Process Research Articles

Cationic Imidazolium-Urethane-Based Poly(Ionic Liquids) Membranes for Enhanced CO2/CH4 Separation: Synthesis, Characterization, and Performance Evaluation

The escalating emissions of CO2 into the atmosphere require the urgent development of technologies aimed at mitigating environmental impacts. Among these, aqueous amine solutions and polymeric membranes, such as cellulose acetate and polyimide are commercial technologies requiring improvement or substitution to enhance the economic and energetic efficiency of CO2 separation processes. Ionic liquids and poly(ionic liquids) (PILs) are candidates to replace conventional CO2 separation technologies. PILs are a class of materials capable of combining the favorable gas affinity exhibited by ionic liquids (ILs) with the processability inherent in polymeric materials. In this context, the synthesis of the IL GLYMIM[Cl] was performed, followed by ion exchange processes to achieve GLYMIM variants with diverse counter anions (NTf2−, PF6−, and BF4). Subsequently, PIL membranes were fabricated from these tailored ILs and subjected to characterization, employing techniques such as SEC, FTIR, DSC, TGA, DMA, FEG-SEM, and CO2 sorption analysis using the pressure decay method. Furthermore, permeability and ideal selectivity assessments of CO2/CH4 mixture were performed to derive the diffusion and solubility coefficients for both CO2 and CH4. PIL membranes exhibited adequate thermal and mechanical properties. The PIL-BF4 demonstrated CO2 sorption capacities of 33.5 mg CO2/g at 1 bar and 104.8 mg CO2/g at 10 bar. Furthermore, the PIL-BF4 membrane exhibited permeability and ideal (CO2/CH4) selectivity values of 41 barrer and 44, respectively, surpassing those of a commercial cellulose acetate membrane as reported in the existing literature. This study underscores the potential of PIL-based membranes as promising candidates for enhanced CO2 capture technologies.

Cationic Imidazolium-Urethane-Based Poly(Ionic Liquids) Membranes for Enhanced CO2/CH4 Separation: Synthesis, Characterization, and Performance Evaluation

The escalating emissions of CO2 into the atmosphere require the urgent development of technologies aimed at mitigating environmental impacts. Among these, aqueous amine solutions and polymeric membranes, such as cellulose acetate and polyimide are commercial technologies requiring improvement or substitution to enhance the economic and energetic efficiency of CO2 separation processes. Ionic liquids and poly(ionic liquids) (PILs) are candidates to replace conventional CO2 separation technologies. PILs are a class of materials capable of combining the favorable gas affinity exhibited by ionic liquids (ILs) with the processability inherent in polymeric materials. In this context, the synthesis of the IL GLYMIM[Cl] was performed, followed by ion exchange processes to achieve GLYMIM variants with diverse counter anions (NTf2−, PF6−, and BF4). Subsequently, PIL membranes were fabricated from these tailored ILs and subjected to characterization, employing techniques such as SEC, FTIR, DSC, TGA, DMA, FEG-SEM, and CO2 sorption analysis using the pressure decay method. Furthermore, permeability and ideal selectivity assessments of CO2/CH4 mixture were performed to derive the diffusion and solubility coefficients for both CO2 and CH4. PIL membranes exhibited adequate thermal and mechanical properties. The PIL-BF4 demonstrated CO2 sorption capacities of 33.5 mg CO2/g at 1 bar and 104.8 mg CO2/g at 10 bar. Furthermore, the PIL-BF4 membrane exhibited permeability and ideal (CO2/CH4) selectivity values of 41 barrer and 44, respectively, surpassing those of a commercial cellulose acetate membrane as reported in the existing literature. This study underscores the potential of PIL-based membranes as promising candidates for enhanced CO2 capture technologies.

The Synergetic Reduction of the Condensation Degree of Dissolved Lignin (DL) during the Refining Process of Wheat Straw Biomass Based on the MA/O3 System.

Lignin, a natural pol2ymer with a complex structure that is difficult to separate, is prone to C-C bond condensation during the separation process. To reduce the condensation of lignin, here, a novel method is proposed for separating the components by using a combination of maleic acid (MA)/ozone (O3) to co-treat wheat straw. The removal of lignin, glucan, and xylan was 38.07 ± 0.2%, 31.44 ± 0.1%, and 71.98 ± 0.1%, respectively, under the conditions of ball-milling of wheat straw for 6 h, reaction temperature of 60 °C, and O3 holding time of 9 min. Lignin-rich solutions were collected to extract the dissolved lignin (DL) after washing the treated samples. The DL obtained under MA/O3 conditions had a carboxyl group (-COOH) content of 2.96 mmol/g. The carboxyl group of MA underwent esterification with the hydroxyl group (-OH) at the γ position of lignin and O3 reacted on the positions of the lignin side chain or the phenolic ring, resulting in a break in the side chain and the opening of the phenolic ring to introduce the carboxyl group. The 2D-HSQC-NMR results revealed that the phenolic ring-opening reaction of lignin in the presence of O3 was essentially free of β-β and β-5 condensation bonds.

Exploring the feasibility of Zr-based metal-organic frameworks for the recovery of Sb (V) and Sb (III) from mining waste.

The present study investigates the efficacy of newly developed Zr-based metal-organic frameworks, specifically MIP-206, and its amine-modified counterpart, MIP-206-NH2, for the re-covery of antimony (Sb) from both synthetic and actual mining wastewater. Batch method studies were employed to examine the effect of waste media pH, Sb concentration, process kinetics, and the performance of the regeneration solution. MIP-206-NH2 exhibited impressive separation capabilities, achieving 102.18 mg/g and 63.23 mg/g for Sb (V) and Sb (III), respectively. In contrast, the pristine MIP-206 reached maximum values of 26.26 mg/g for Sb (V) and 16.95 mg/g for Sb (III). The separation process was well-described by the Langmuir equation, and the kinetics followed the pseudo-second-order model. Although the amine modification resulted in a decrease in the surface area of MIP-206 from 1345.21 to 1169.86 m2/g, SEM and XRD analyses confirmed that the structural integrity of MIP-206-NH2 remained unchanged. In terms of reusability, MIP-206-NH2 maintained up to 90% of its separation performance over 9 cycles, while MIP-206 demonstrated effectiveness for 7 cycles. The regeneration solution exhibited a capacity of approximately 0.63 mol/L for Sb (V) and 0.71 mol/L for Sb (III). Furthermore, MIP-206 and MIP-206-NH2 demonstrated successful application in selectively separating Sb from real mining wastewater.

The Synergetic Reduction of the Condensation Degree of Dissolved Lignin (DL) during the Refining Process of Wheat Straw Biomass Based on the MA/O3 System

Lignin, a natural pol2ymer with a complex structure that is difficult to separate, is prone to C-C bond condensation during the separation process. To reduce the condensation of lignin, here, a novel method is proposed for separating the components by using a combination of maleic acid (MA)/ozone (O3) to co-treat wheat straw. The removal of lignin, glucan, and xylan was 38.07 ± 0.2%, 31.44 ± 0.1%, and 71.98 ± 0.1%, respectively, under the conditions of ball-milling of wheat straw for 6 h, reaction temperature of 60 °C, and O3 holding time of 9 min. Lignin-rich solutions were collected to extract the dissolved lignin (DL) after washing the treated samples. The DL obtained under MA/O3 conditions had a carboxyl group (-COOH) content of 2.96 mmol/g. The carboxyl group of MA underwent esterification with the hydroxyl group (-OH) at the γ position of lignin and O3 reacted on the positions of the lignin side chain or the phenolic ring, resulting in a break in the side chain and the opening of the phenolic ring to introduce the carboxyl group. The 2D-HSQC-NMR results revealed that the phenolic ring-opening reaction of lignin in the presence of O3 was essentially free of β-β and β-5 condensation bonds.

Novel Benzothiadiazole-based Donor-Acceptor Systems: Synthesis, Ultrafast Charge Transfer and Separation Dynamics.

Near-infrared (NIR) absorbing electron donor-acceptor (D-A) chromophores have been at the forefront of current energy research owing to their facile charge transfer (CT) characteristics, which are primitive for photovoltaic applications. Herein, we have designed and developed a new set of benzothiadiazole (BTD)-based tetracyanobutadiene (TCBD)/dicyanoquinodimethane (DCNQ)-embedded multimodular D-A systems (BTD1-BTD6) and investigated their inherent photo-electro-chemical responses for the first time having identical and mixed terminal donors of variable donor-ability. Apart from poor luminescence, the appearance of broad low-lying optical transitions extendable even in the NIR region (> 1000 nm), particularly in the presence of the auxiliary acceptors, are indicative of underlying nonradiative excited state processes leading to strong intramolecular CT and subsequent charge separation (CS) processes in these D-A constructs. The spectral and temporal responses of different photoproducts are obtained from transient studies. All the systems are found to be susceptible to ultrafast (~ps) CT and CS before carrier recombination to the ground state, which is, however, significantly facilitated after incorporation of the secondary TCBD/DCNQ acceptors, leading to faster and thus efficient CT processes. These findings are likely to expand the horizons of BTD-based multimodular CT systems to revolutionize the realm of solar energy conversion and associated photonic applications.

Liquid-Liquid Phase Separation Mediated Formation of Chiral 2D Crystalline Nanosheets of a Co-Assembled System.

The role of macromolecule-macromolecule and macromolecule-H2O interactions and the resulting perturbation of the H-bonded network of H2O in the liquid-liquid phase separation (LLPS) process of biopolymers are well-known. However, the potential of the hydrated state of supramolecular structures (non-covalent analogs of macromolecules) of synthetic molecules is not widely recognized for playing a similar role in the LLPS process. Herein, LLPS occurred during the co-assembly of hydrated supramolecular vesicles (bolaamphiphile, BA1) with a net positive charge (zeta potential, ζ = +60 ± 2mV) and a dianionic chiral molecule (disodium l-[+]-tartrate) is reported. As inferred from cryo-transmission electron microscopy (TEM), the LLPS-formed droplets serve as the nucleation precursors, dictating the structure and properties of the co-assembly. The co-assembled structure formed by LLPS effectively integrates the counter anion's asymmetry, resulting in the formation of ultrathin free-standing, chiral 2D crystalline sheets. The significance of the hydrated state of supramolecular structures in influencing LLPS is unraveled through studies extended to a less hydrated supramolecular structure of a comparable system (BA2). The role of LLPS in modulating the hydrophobic interaction in water paves the way for the creation of advanced functional materials in an aqueous environment.

Novel Benzothiadiazole-based Donor-Acceptor Systems: Synthesis, Ultrafast Charge Transfer and Separation Dynamics.

Near-infrared (NIR) absorbing electron donor-acceptor (D-A) chromophores have been at the forefront of current energy research owing to their facile charge transfer (CT) characteristics, which are primitive for photovoltaic applications. Herein, we have designed and developed a new set of benzothiadiazole (BTD)-based tetracyanobutadiene (TCBD)/dicyanoquinodimethane (DCNQ)-embedded multimodular D-A systems (BTD1-BTD6) and investigated their inherent photo-electro-chemical responses for the first time having identical and mixed terminal donors of variable donor-ability. Apart from poor luminescence, the appearance of broad low-lying optical transitions extendable even in the NIR region (> 1000 nm), particularly in the presence of the auxiliary acceptors, are indicative of underlying nonradiative excited state processes leading to strong intramolecular CT and subsequent charge separation (CS) processes in these D-A constructs. The spectral and temporal responses of different photoproducts are obtained from transient studies. All the systems are found to be susceptible to ultrafast (~ps) CT and CS before carrier recombination to the ground state, which is, however, significantly facilitated after incorporation of the secondary TCBD/DCNQ acceptors, leading to faster and thus efficient CT processes. These findings are likely to expand the horizons of BTD-based multimodular CT systems to revolutionize the realm of solar energy conversion and associated photonic applications.

Evaluation of dimethyl carbonate production process from CO2 by rigorous simulation and detailed optimization

AbstractThe CO2‐derived dimethyl carbonate (DMC) synthesis process becomes greatly attentive but suffers high energy consumption in DMC distillation process. In this work, the DMC‐MeOH azeotropes separation process by pressure swing distillation and extractive distillation was compared, and key operating parameters, including the total number of trays and the feeding position of the mixture liquid, were optimized with the minimum total annual cost (TAC) as the objective function. On the basis of this optimization, economic evaluation of different distillation processes was conducted, and it was found that extractive distillation was more economical than pressure swing distillation. The application of the dividing‐wall distillation process upgraded by extractive distillation can significantly reduce the minimum annual total cost by 37.4% and 10.7% compared to the original pressure swing distillation and extractive distillation process, respectively. The optimization of relevant heat exchange network based on pinch technology resulted in energy consumption reduction by 27.2% and 25.9% for its hot and cold utilities, respectively. Carbon life cycle assessment (LCA) on the DMC distillation process revealed over 50% of energy as well as carbon emissions from steam consumption, whose reduction can significantly minimize CO2 emissions, energy consumption, and ultimate cost. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Adsorption and transport of acid dye through polymer inclusion membrane with Aliquat 336 and TBP

Colour is typically the initial pollutant identified in wastewater. Membrane separation represents a novel approach to separation processes, with expectations of supplanting many traditional separation systems. The aim of this study is to investigate polymer inclusion membranes (PIMs) consisting of tri octyl methyl ammonium chloride as the carrier, tributylphosphate as the modifier, poly-vinyl chloride as the base polymer and 2-Nitro phenyl pentyl ether as the plasticizer for removing an acid dye (Red Erionyl A-3G) from aqueous solution. The dye adsorption on the membrane surface and its transition to the stripping phase was achieved by placing the membrane between two glass cells. Changing the stripping solution ensured both adsorption on the membrane surface and the transfer of all the dye to the stripping stage. Using a mixture of 0.8 M salicylic acid and 0.8 M NaOH, along with stirring at 1000 rpm during the stripping phase, extraction efficiency reached 98% in the feed phase and 53% in the stripping phase. When 1 M NaOH solution was employed as the stripping solution, the membrane absorbed all the dye within 10 minutes, but there was no transition to the stripping phase. The membrane has a durability of 2 days.Graphical abstract

Self-Repairing Humidity-Adjustable Anisotropic Adhesion Switch for Smart Manipulation.

Stimuli-responsive surface adhesion regulation is widely used in automated assembly systems, intelligent pick-up and placement systems, and soft crawling robots. However, in the actual separation process, it tends to produce separation residue or excessive adhesion. Therefore, how to regulate surface adhesion on demand is a significant challenge. Herein, inspired by the anisotropic adhesion behavior of butterflies and the controlled adhesion behavior of octopuses, based on molecular conformational rearrangement and anisotropic structures, a humidity-responsive PES-PI/PDMS composite surface is achieved to meet the needs of controllable adhesion orientation and strength, which could be used for an intelligent transfer system (grasping and releasing and anisotropic transporting). Humidity can effectively tune the hydrogen bonding and the interaction between polymers, resulting in excellent self-healing and durability properties of the composite surface. Moreover, humidity could adjust the surface transmittance as well, making it possible to be used in humidity sensing and in a detection and encryption/decryption system to enhance environmental monitoring and information protection capabilities. This work not only establishes a method for the fabrication of innovative "high-flexibility" adhesive materials but also provides approaches for the design and development of intelligent response devices.

Design and control of a novel multi-product extractive dividing wall column process for recycling organics from wastewater

The wastewater from a pharmaceutical plant consists of a tetrahydrofuran/isopropanol/water azeotrope. This investigation utilizes dimethyl sulfoxide as an extractant and employs an extractive dividing wall column to separate the aforementioned azeotrope. The extractive dividing wall columns are constructed with single, double, and triple partition walls, and a multi-objective genetic algorithm is used to optimize the operational parameters of the separation process. Of these columns, the extractive dividing wall columns with triple partition walls show the most favorable economic, environmental, and energy utilization performance, and it has a lower risk of combustion and explosion. Compared to the conventional design, the use of triple-partition extractive dividing wall columns results in a 22.13 % and 10.54 % reduction in total annual cost and CO2 emissions, respectively, and an increase in thermodynamic efficiency of 2.66 %. Studying the dynamic characteristics of this process reveals its excellent dynamic controllability.

Study on particle size and density segregation law in the separating process of poor quality coal with high gangue content under the action of composite force field

ABSTRACT Thin-seam mining frequently captures a significant proportion of gangue and interbedded coal in surface coal mines. Consequently, raw coal has a broad range of particle size distributions and a high percentage of components with intermediate densities, which are complex and challenging to separate. This study aims to determine the method of product division and the segregation law of particle size and density of raw coal during the separation process using a vibration and airflow composite force field. A difference in the particle size segregation of the coal particles was evident. Particle-size segregation primarily occurs in the separation area. Large-particle-size coal has a wide distribution range, spreading over the entire bed and fully utilizing the bed to achieve separation. The material becomes increasingly displaced into the separation area as its particle size decreases, thereby weakening the separation effect. Large coal particles can undergo density segregation in the vertical direction, with low-density material placed in the upper layer. This ensures that low-density material is incorporated into the refined coal product. Regardless of density, the coal tended to tilt more toward the bottom layer as the particle size decreased. This results in a poor density stratification effect with refined coal products mixed with gangue and an increase in the mismatch content. The extent of fine coal discharge was determined to be two-fifths of the entire length of the discharge side. This ensures that the majority of refined coal is recovered and that there is no excessive gangue mixing with the refined coal output. Achieving a 55.54% yield, refined coal lowers its ash content by 16%, increases its calorific value by 1400 kcal/kg, and effectively separates coal with a high gangue concentration.

Sustainable and efficient recovery of lithium from rubidium raffinate via solvent extraction

In recent years, with the increasing prevalence of rechargeable lithium-ion batteries in the burgeoning markets of electric vehicles and portable electronic devices, the consumption of lithium batteries has significantly surged. Hence, the efficient development and utilization of associated lithium resources bear paramount significance. This study aims to recover lithium from rubidium raffinate via solvent extraction. A systematic investigation was conducted to examine the effects of various parameters such as organic phase concentration, contact time, and phase ratio (O/A) during the separation process. The results indicated that the organic phase composed of 0.1 mol/L 4,4,4-Trifluoro-1-phenyl-1,3-butanedione (HBTA) and 0.1 mol/L Trioctylphosphine oxide (TOPO) could efficiently extract lithium from the rubidium raffinate. The optimal conditions were observed at a temperature of 20℃, O/A=1, and a contact time of 5 min. After three-stage countercurrent extraction, a lithium extraction rate of 99.24 % could be achieved, with over 95 % of the sodium easily scrubbed by 0.1 mol/L HCl at an O/A=10. With the use of 3 mol/L HCl, stripping efficiency exceeding 99 % could be attained at an O/A=10, consequently a successful preparation of battery-grade lithium carbonate product was achieved. Regeneration experiments confirmed the organic phase's excellent reproducibility efficiency. Slope analysis and density function theory (DFT) simulations indicated that optimal lithium extraction is achieved when HBTA and TOPO are at equal molar concentrations. The proposed process is expected to provide a green and sustainable route for the recovery of associated lithium resources.

Enhancement of CO2/N2 separation in MMMs by the regulation of nanofiller microenvironment

Mixed-matrix membranes (MMMs) incorporating Metal-Organic Frameworks (MOFs) represent a promising approach for gas separation, which can combine the advantages of selective adsorbents and processable polymers, and display great potential in the gas separation process. However, the further application of MMMs is severely impeded owing to the non-ideal interface between fillers and polymer matrix. In this work, a series of MIL-101(Cr) nanofillers, equipped with different kinds of counter anions were introduced to regulate the chemical microenvironment of the MMMs and improve the interfacial relationship between inorganic filler and polymer. The filler of MIL-101-HNO3 exhibits improved dispersibility in solvents and heightened interface relationship with the polymer matrix (PIM-1) due to its optimal particle size and distinctive exposure of crystallographic planes. Moreover, gas sorption isotherms reveal that the MIL-101-HNO3 MOF show reduced N2 adsorption capacity. Therefore, the MOF filler of MMMs were optimized rationally by microenvironment regulate strategy, leading to the MIL-101-HNO3/PIM-1 MMMs achieve high CO2 permeability and exceptional CO2/N2 ideal selectivity (CO2 = 14879 barrer, CO2/N2 = 24.3), surpassing the latest 2019 upper bound. That makes MIL-101-HNO3/PIM-1 a potential candidate for the selective removal of CO2 from stack gas and provides new insights into the regulation of the MMMs nanofiller microenvironment.

Investigation of cold tube structure on flow characteristics and energy separation in vortex tube based on numerical and thermodynamic analyses

A combined approach of computational fluid dynamics modelling, experimental validation and thermodynamic analysis is used to investigate the effect of cold end tube geometry (namely, straight tube, divergent tube, convergent tube, and convergent-divergent tube) on flow characteristics and energy separation, which to improve the energy efficiency and sustainability of the vortex tube in industrial applications. The analyses indicate that the highest axial velocity (212 m/s) and swirl velocity (193 m/s) at different axial locations in the cold tube are demonstrated in the divergent and convergent-divergent structures, respectively. The divergent tube shows better energy separation at lower cold mass fraction, while the convergent-divergent tube is dominant at higher cold mass fraction. The highest coefficient of performance is found at μc = 0.6, with maximum cooling and heating energy transfer efficiencies of 0.112 and 0.103, respectively. By innovatively incorporating the work-heat transfer theory into structural investigation of cold tubes, it is found that tangential viscous shear effect is the dominant factor in energy separation process. It is noteworthy that the highest net energy transfer of 973 W is achieved by convergent-divergent tube at a cold mass fraction of 0.7.

Synthesis of a novel polymer and design of carboxylate-terminated hyperbranched PEI-incorporated PVDF membranes for efficient oil-in-water emulsion separation

Polyvinylidene fluoride (PVDF) membranes utilizing ultrafiltration (UF) and microfiltration (MF) configurations have widely been used in many separation processes, including oil/water emulsions. Recently, there have been tremendous research interests in designing PVDF membranes on their structural-property relations as well as high separation performances. Herein we report the synthesis of a novel carboxylate-terminated hyperbranched polyethylenimine (CHPEI) using a facile three-step one-pot strategy to enhance the characteristics of PVDF membranes for oil/water emulsion separation. The first step involved the production of one amide and one carboxylate functional group per maleic anhydride molecule on the outer surface of polyethylenimine (PEI). The second step involved producing two additional carboxylate groups via amine-based Michael addition of alkenes using aspartic acid dimethyl ester hydrochloride, followed by basic hydrolysis. CHPEI-n-PVDF membranes having various CHPEI contents are further fabricated by a phase-inversion process, obtaining as free-stable flat-sheet membranes. The synthesized polymer and membranes were thoroughly characterized by FTIR and 1H NMR, SEM, EDX, mapping, AFM, and contact angle analysis. The incorporation of CHPEI into PVDF positively enhanced the hydrophilicity, and the WCA was significantly reduced from 80.6° to 59.5°. The maximum permeation flux was obtained using CHPEI-3-PVDF membranes, which was 200 % more than that obtained using pristine PVDF. The CHPEI-2-PVDF membranes exhibited a rejection performance of >99 % for separating oil-in-water emulsions. The incorporation of CHPEI into PVDF significantly improved the antifouling characteristics of the membranes. After 5 h of operation in separating oil-in-water emulsions, the flux recoveries of CHPEI-2-PVDF and CHPEI-3-PVDF were found to be 92 % and 97 %, respectively. CHPEI has demonstrated a considerable positive influence in improving the PVDF membrane’s performance, making it an excellent candidate for oily wastewater treatment because of its high rejection performance and excellent flux recovery ratio.

Design of dual mode antenna using CMA and broadband dual-polarized antenna for 5G networks

This article proposes a dual mode dual-polarized antenna configuration for IRNSS and fifth generation (5G) applications, operating at a frequency of 3.5 GHz based on characteristic mode analysis (CMA), and aims to provide broadband dual-polarized functionality. The original design of the antenna is a traditional patch antenna, and its dual-polarized features are determined using characteristic mode analysis. The full-wave method is used to stimulate both orthogonal modes using a 50 Ω coaxial input line at 3.5 GHz. In this design, the circular patch has been extended into an elliptical patch through a process of mode separation. The circular patch exhibits resonance at a frequency of 2.5 GHz, whereas the extended elliptical radiator demonstrates two resonance modes at 2.5 GHz and 3.5 GHz. The operational mechanism is elucidated by modal analysis and characteristic angle. This antenna operates on two different frequencies at the 2.5 GHz IRNSS band with horizontal polarization and the 3.5 GHz 5G service with vertical polarization. The maximum gain achieved with these frequency ranges is 5.31 dBi and 4.72 dBi, respectively. A ring resonator is chosen to improve the axial ratio and impedance bandwidth of the suggested prototype. The antenna's ground plane is shaped like a rectangle and features a V-shaped slot in the radiating patch. The antenna's physical footprint is 50 mm × 50 mm × 1.6 mm and an FR4 dielectric substrate serves as its foundation. Through its interaction with a PIN diode, the diode modifies the polarization of the antenna. The antenna functions as a right-handed circular polarization (RHCP), when the diode is operational. The bandwidth from 4.3 to 7.5 GHz is covered. On the other hand, it generates linear polarization (LP) between 4.2 and 5.3 GHz. The experimental antenna is evaluated and examined for its performance characteristics. The simulations are carried out utilizing the CST simulator. A prototype antenna has been manufactured and its performance has been validated against simulated findings.

Factors that Impact the Efficiency of Cream Separator Machine for the Food Industry

This study examines the variables that impact the effectiveness of cream separator machines in the dairy sector, with a specific emphasis on centrifugal force, temperature, and vibration. The process of cream separation, which is crucial in dairy production, has progressed from manual techniques to sophisticated mechanical centrifugal separators. The objective of this study is to optimize the performance of these machines, which is imperative due to the increasing need for low-fat skimmed milk. The study utilizes a disc centrifuge to examine the impact of centrifugal forces. The setup consists of more than 24 discs, which are used to measure the volume of fluid passing through the spaces between the discs and to determine the efficiency of separation. The experiments involved using flow rates of 600 ml/min, 1200 ml/min, and 1800 ml/min to alter the temperature from 7 °C to 15 °C, 25 °C, and 35 °C. The findings indicated that decreased temperatures significantly enhance the efficiency of skimming. The study also examines the impact of machine-induced vibration on the efficiency of separation. The study concludes that excessive vibration negatively impacts productivity, therefore, it is essential to incorporate vibration control into the design of separators. The key findings suggest that optimizing centrifugal force is crucial. Inadequate force leads to incomplete separation of fat, while higher flow rates decrease separation efficiency. Temperature regulation is equally crucial, and reducing temperatures enhances efficiency. Effective vibration control is essential for maintaining optimal separation quality. This study makes a valuable contribution to the advancement of cream separator machines by highlighting the importance of accurate management of centrifugal force, temperature, and vibration. This is crucial for enhancing productivity and meeting the requirements of the market. The findings offer valuable insights for the dairy industry, assisting in the development and functioning of advanced cream separators that provide enhanced performance and economic advantages for producers.

In Situ Transformation of an Amorphous Supramolecular Coating to a Hydrogen-Bonded Organic Framework Membrane to Trigger Selective Gas Permeation.

We introduce a "solution-processing-transformation" strategy, deploying solvent vapor as scaffolds, to fabricate high-quality hydrogen-bonded organic framework (HOF) membranes. This strategy can overcome the mismatch in processing conditions and crystal growth thermodynamics faced during the facile solution processing of the membrane. The procedure includes the vapor-trigged in situ transformation of dense amorphous supramolecules to crystalline HOF-16, with HOF-11 as the transient state. The mechanism involves a vapor-activated dissolution-precipitation equilibrium shifting and hydrogen bonding-guided molecule rearrangement, elucidated through combined experimental and theoretical analysis. Upon removal of the molecular scaffolds, the resulting HOF-16 membranes showcase significant improvement in hydrogen separation performance over their amorphous counterparts and previously reported HOF membranes. The method's broad applicability is evidenced by successfully extending it to other substrates and HOF structures. This study provides a fundamental understanding of guest-induced ordered supramolecular assembly and paves the way for the advanced manufacture of high-performance HOF membranes for gas separation processes.