Modification Techniques Research Articles

Plasma-based base flow modification on swept-wing boundary layers: dependence on flow parameters

This work examines the control of cross-flow instabilities (CFIs) and laminar–turbulent transition on a swept wing, through the plasma-based base flow modification (BFM) technique. The effect of experimentally derived plasma body forces on the steady boundary layer base flow is explored through numerical simulations. Linear stability theory is subsequently used to predict the net BFM effect on CFIs. Based on these preliminary predictions, experiments are conducted in a low-turbulence wind tunnel where a spanwise-invariant plasma actuator is installed near the wing leading edge and operated at constant input voltage and frequency. Various flow parameters governing the plasma-based BFM technique are investigated, namely the Reynolds number, angle of attack and wavelength of excited stationary CFI modes. Stationary and travelling CFIs are quantified by planar particle image velocimetry while the transition topology and location are recorded by infrared thermography. The results confirm the stabilising effect of BFM on the swept-wing boundary layer. However, the plasma-based BFM is found to render the boundary layer more susceptible to travelling CFIs. In the presence of both net BFM effect and intrinsic plasma unsteady perturbations, the plasma-based BFM technique achieves transition delay with specific combinations of Reynolds number, angle of attack and wavelength of excited stationary CFI modes. The present findings provide insights into the fundamental principles of operating plasma actuators within the context of BFM control.

Transforming Petrochemical Processes: Cutting-Edge Advances in Kaolin Catalyst Fabrication

The depletion of conventional light petroleum reserves has intensified the search for alternative sources, notably, low-quality heavy oils and byproducts from heavy crude processing, to meet the global demand for fuels, energy, and petrochemicals. Heavy crude oil (HO) and extra heavy crude oil (EHO) represent nearly 70% of the world’s reserves but require extensive upgrading to satisfy refining and petrochemical specifications. Their high asphaltene content results in elevated viscosity and reduced API gravity, posing significant challenges in extraction, transportation, and refining. Advanced catalytic approaches are crucial for efficient asphaltene removal and the conversion of heavy feedstocks into valuable light fractions. Kaolin, an aluminosilicate mineral, has emerged as a key precursor for zeolite synthesis and a promising catalyst in upgrading processes. This article provides a comprehensive exploration of kaolin’s geological origins, chemical properties, and structural characteristics, as well as the various modification techniques designed to improve its catalytic performance. Special focus is given to its application in the transformation of heavy crudes, particularly in facilitating asphaltene breakdown and enhancing light distillate yields. Finally, future research avenues and potential developments in kaolin-based catalysis are discussed, emphasizing its vital role in addressing the technological challenges linked to the growing reliance on heavier crude resources.

Immunomodulatory Biomaterials: Tailoring Surface Properties to Mitigate Foreign Body Reaction and Enhance Tissue Regeneration.

The immune cells have demonstrated the ability to promote tissue repair by removing debris, breaking down the extracellular matrix, and regulating cytokine secretion profile. If the behavior of immune cells is not well directed, chronic inflammation and foreign body reaction (FBR) will lead to scar formation and loss of biomaterial functionality. The immunologic response toward tissue repair or chronic inflammation after injury and implantation can be modulated by manipulating the surface properties of biomaterials. Tailoring surface properties of biomaterials enables the regulation of immune cell fate such as adhesion, proliferation, recruitment, polarization, and cytokine secretion profile. This review begins with an overview of the role of immune cells in tissue healing and their interactions with biomaterials. It then discusses how the surface properties of biomaterials influence immune cell behavior. The core focus is reviewing surface modification methods to create innovative materials that reduce foreign body reactions and enhance tissue repair and regeneration by modulating immune cell activities. The review concludes with insights into future advancements in surface modification techniques and the associated challenges.

Research on the laser melting coating process of an AlCoCrFeNi high‐entropy alloy

AbstractLaser cladding technology is an advanced surface modification technique that has gained significant attention in various fields due to its energy savings, efficiency, and environmental friendliness. This paper discusses the preparation of AlCoCrFeNi high‐entropy alloy (HEA) coatings on the surface of a 5083 aluminum alloy using laser cladding technology under the Ar gas conditions. An orthogonal test system was used to optimize the laser cladding process parameters. The microstructure, as well as the mechanical, frictional, and electrochemical properties of the HEA coatings, were comparatively analyzed under the two process conditions S4 and S10. The results indicate that, under S10, the HEA coatings exhibit optimal surface quality. The coatings contained a mixture of Face‐centered cubic (FCC) and Body‐centered cubic (BCC) phases. Microscopic examination revealed three distinct areas: dark, gray, and off‐white. The coatings can significantly improve the wear and corrosion resistance of the alloy substrate. For the best results, it is set the laser power to 200 W, the laser scanning distance to .05 mm, and the laser scanning rate to 1250 mm/s. This present study offers a novel technical foundation for the fabrication of HEA coatings.

Emerging ZnO Semiconductors for Photocatalytic CO2 Reduction to Methanol.

Carbon recycling is poised to emerge as a prominent trend for mitigating severe climate change and meeting the rising demand for energy. Converting carbon dioxide (CO2) into green energy and valuable feedstocks through photocatalytic CO2 reduction (PCCR) offers a promising solution to global warming and energy needs. Among all semiconductors, zinc oxide (ZnO) has garnered considerable interest due to its ecofriendly nature, biocompatibility, abundance, exceptional semiconducting and optical properties, cost-effectiveness, easy synthesis, and durability. This review thoroughly discusses recent advances in mechanistic insights, fundamental principles, experimental parameters, and modulation of ZnO catalysts for direct PCCR to C1 products (methanol). Various ZnO modification techniques are explored, including atomic size regulation, synthesis strategies, morphology manipulation, doping with cocatalysts, defect engineering, incorporation of plasmonic metals, and single atom modulation to boost its photocatalytic performance. Additionally, the review highlights the importance of photoreactor design, reactor types, geometries, operating modes, and phases. Future research endeavors should prioritize the development of cost-effective catalyst immobilization methods for solid-liquid separation and catalyst recycling, while emphasizing the use of abundant and non-toxic materials to ensure environmental sustainability and economic viability. Finally, the review outlines key challenges and proposes novel directions for further enhancing ZnO-based photocatalytic CO2 conversion processes.

A Review on Recent Trends in Photo-Drug Efficiency of Advanced Biomaterials in Photodynamic Therapy of Cancer.

Photodynamic Therapy (PDT) has emerged as a highly efficient and non-invasive cancer treatment, which is crucial considering the significant global mortality rates associated with cancer. The effectiveness of PDT primarily relies on the quality of the photosensitizers employed. When exposed to appropriate light irradiation, these photosensitizers absorb energy and transition to an excited state, eventually transferring energy to nearby molecules and generating Reactive Oxygen Species (ROS), including singlet oxygen [1O2]. The ability to absorb light in visible and nearinfrared wavelengths makes porphyrins and derivatives useful photosensitizers for PDT. Chemically, Porphyrins, composed of tetra-pyrrole structures connected by four methylene groups, represent the typical photosensitizers. The limited water solubility and bio-stability of porphyrin photosensitizers and their non-specific tumor-targeting properties hinder PDT effectiveness and clinical applications. Therefore, a wide range of modification and functionalization techniques have been used to maximize PDT efficiency and develop multidimensional porphyrin-based functional materials. Recent progress in porphyrin-based functional materials has been investigated in this review paper, focusing on two main aspects including the development of porphyrinic amphiphiles that improve water solubility and biocompatibility, and the design of porphyrin-based polymers, including block copolymers with covalent bonds and supramolecular polymers with noncovalent bonds, which provide versatile platforms for PDT applications. The development of porphyrin-based functional materials will allow researchers to significantly expand PDT applications for cancer therapy by opening up new opportunities. With these innovations, porphyrins will overcome their limitations and push PDT to the forefront of cancer treatment options.

Comparative evaluation of three different behavior management techniques among children aged 6-12 years in dental practice: A single-center, double-blind, randomized controlled trial.

Dental anxiety is characterized by distress in anticipation of dental visits, which may result in a child's refusal to undergo treatment and, ultimately, lead to parents' reluctance towards dental care. The aim of this study was to evaluate and compare the effectiveness of the tell-show-do technique, modeling technique and yogic relaxation technique in the reduction of dental anxiety among children aged 6-12 years. The study was an interventional, parallel-group, single-center, double-blind, randomized controlled trial conducted on 120 children who required restorative treatment without the use of local anesthesia. The participants were selected based on specific inclusion and exclusion criteria and were randomly divided into 3 groups: group 1 - tell-show-do technique; group 2 - modeling technique; group 3 - yogic relaxation technique. The dental anxiety levels were evaluated 4 times using both physiological (oxygen saturation and pulse rate) and behavioral parameters (facial image scale (FIS) and the Face, Legs, Activity, Cry, and Consolability scale (FLACC)). The data was assessed by 2 blinded and calibrated specialists. Statistically significant differences were observed in all 4 parameters among the 3 groups. During both the intraoperative and postoperative periods, the oxygen saturation levels were significantly higher in the yogic relaxation technique group. Moreover, the yogic relaxation technique group exhibited lower pulse rates, FIS and FLACC scores compared to the tell-show-do and modeling technique groups. The practice of yoga has a positive influence on the general health of the individual. Consequently, it can be considered one of the alternative behavioral modification techniques for the reduction of dental anxiety in children.

Modification approaches of walnut proteins to improve their structural and functional properties: A review

Walnut protein has a high gluten content and compact structure, which limits its water solubility and affects its applications. Therefore, improving the sustainability of walnut proteins is an urgent issue that must be addressed. Physical modification can directly alter the structure of walnut proteins, leading to enhanced functional properties. Chemical modifications typically involve the introduction of exogenous substances that react with walnut proteins to obtain novel products with improved processing attributes. As a highly specific modification technique, biomodification uses enzymes or microorganisms to break down walnut proteins into small peptide molecules or cross-link them to form soluble polymers, thereby enhancing their functional properties and bioactivity. This review presents various methods for modifying walnut proteins and their effects on the structure and functional properties of walnut proteins. The challenges associated with the application and development of these unique technologies are also discussed.

Effects of hydrogen on the fretting wear behavior of laser cladded FeCoCrNiMo0.2 high entropy alloy coating

This study investigates laser-cladded high entropy alloy (HEA) coatings on high-speed train axles to enhance wear resistance under specific fretting conditions. Axles in humid and acidic environments absorb hydrogen, leading to accumulation in grain boundaries, which weakens their structure and causes damage under alternating stress. Despite this, the impact of hydrogen damage on the fretting wear behavior of HEA coatings has not been explored. To address this, we performed fretting wear tests on a laser-cladded FeCoCrNiMo0.2 coating and a GCr15 steel ball friction system, evaluating their performance before and after hydrogen exposure. The results of the study indicate that under a constant load of Fn = 10N and a displacement amplitude of D = 50 μm, the friction coefficient, maximum wear depth, wear volume, and wear rate increased when the system was in the hydrogen charging state compared to the non-hydrogen charging state. Specifically, the friction coefficient increased from 0.60 to 0.93, the maximum wear depth increased from 2.82 μm to 3.63 μm, the wear volume increased from 14.106 × 104μm3 to 22.098 × 104μm3, and the wear rate increased from 28.213 × 10−6 mm/Nm to 36.600 × 10−6 mm/Nm. Under the hydrogen charging state, the friction coefficient, maximum wear depth, wear volume, and wear rate all increased. This is due to hydrogen damage, including the formation of pitting pits and cracks on the surface of the coating, stress concentration, and brittle failure caused by hydrogen infiltration into the material. The presence of hydrogen makes the surface of the coating more prone to detachment, resulting in finer wear debris, deeper grooves, and increased oxidation. These factors accelerate the wear of the coating. This finding will contribute to the development and improvement of advanced surface modification techniques for materials in the hydrogen environment.

Photocatalytic Hydrogen Production Using TiO2‐based Catalysts: A Review

AbstractPhotocatalytic water splitting is an environmentally friendly hydrogen production method that uses abundant renewable resources such as water and sunlight. While Titanium dioxide (TiO2) photocatalyst exhibits excellent properties, its high band gap limits absorption to ultraviolet (UV) irradiation, resulting in low photo conversion efficiency. This review explores various modification techniques aimed at enhancing the efficiency of TiO2 under visible light irradiation. Factors influencing the photocatalytic water splitting reaction, such as catalyst structure, morphology, band gap, sacrificial reagents, light intensity, temperature, and potential of Hydrogen (pH) are examined. This review also summarizes different catalyst synthesis methods, and types of photocatalytic reactors, and provides insights into quantum yield. Finally, the review addresses the challenges and future outlook of photocatalytic water splitting.

Advancements in Rechargeable Zn-Air Batteries with Transition-Metal Dichalcogenides as Bifunctional Electrocatalyst.

This review covers recent progress on transition metal dichalcogenides (TMDs) as bifunctional electrocatalysts for Zinc-air batteries (ZABs), emphasizing their suitable surface area, electrocatalytic active sites, stability in acidic/basic environments, and tunable electronic properties. It discusses strategies like defect engineering, doping, interface, and structural modifications of TMDs nanostructures for enhancing the performances of ZABs. Zinc-air batteries are promising energy storage devices owing to their high energy density, low cost, and environmental friendliness. However, the development of durable and efficient bifunctional electrocatalysts is a major concern for Zn-air batteries. In this review, we summarize the recent progress on transition metal dichalcogenides (TMDs) as bifunctional electrocatalysts for Zn-air batteries. We discuss the advantages of TMDs, such as high activity, good stability, and tunable electronic structure, as well as the challenges, such as low conductivity, poor durability, and limited active sites. We also highlight the strategies for fine-tuning the properties of TMDs, such as defect engineering, doping, hybridization, and structural engineering, to enhance their catalytic performance and stability. We provide a comprehensive and in-depth analysis of the applications of TMDs in Zn-air batteries, demonstrating their potential as low-cost, abundant, and environmentally friendly alternatives to noble metal catalysts. We also suggest future directions like exploring new TMDs materials and compositions, developing novel synthesis and modification techniques, investigating the interfacial interactions and charge transfer processes, and integrating TMDs with other functional materials. This review aims to illuminate the path forward for the development of efficient and durable Zn-air batteries, aligning with the broader objectives of sustainable energy solutions.

Unlocking the potential of titanium and its alloys: A mini-review on innovative surface modification techniques

Titanium and its alloys are widely utilized in various fields, such as biomedical and aerospace, and in other industrial applications. However, its surface modification is essential to further enrich its properties to enhance its effectiveness. Researchers across the globe are continuously working on a variety of surface modification methods to enhance the properties of titanium and its alloys. This paper presents a comprehensive review of surface modification methods utilized for titanium and its alloys. Some of the important modification techniques discussed in this paper includes mechanical, chemical, electrochemical, thermal, and physical surface modification methods. This paper also provides insights into surface modification methods in terms of improving corrosion and wear resistance, biocompatibility, and hardness of titanium and its alloys.

Research progress on blood compatibility of hemoperfusion adsorbent materials.

This comprehensive review examines the latest developments in improving the blood compatibility of hemoperfusion adsorbents. By leveraging advanced coating and modification techniques, including albumin-collodion, cellulose, hydrogel, and heparin coatings, notable enhancements in blood compatibility have been achieved across diverse adsorbent types, such as carbon-based, resin-based, and polysaccharide-based materials. Despite promising laboratory results, the intricate manufacturing processes and elevated costs present significant challenges for broad clinical application. Therefore, future endeavors should focus on cost-benefit analysis, large-scale production strategies, in-depth exploration of blood-material interactions, and innovative technologies to propel the development of safer and more effective blood purification therapies.

Novel Biomaterials Based Strategies for Neurodegeneration: Recent Advancements and Future Prospects.

Neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, pose significant challenges for effective treatment due to the complex nature of the central nervous system and the limited delivery of therapeutic agents to the brain. Biomaterial-based drug delivery systems offer promising strategies to overcome these challenges and improve therapeutic outcomes. These systems utilize various biomaterials, such as nanoparticles, hydrogels, and implants, to deliver drugs, genes, or cells to the affected regions of the brain. They provide advantages such as targeted delivery, controlled release, and protection of therapeutic agents. This review examines the role of biomaterials in drug delivery for neurodegeneration, discussing different biomaterialbased approaches, including surface modification, encapsulation, and functionalization techniques. Furthermore, it explores the challenges, future perspectives, and potential impact of biomaterialbased drug delivery systems in the field of neurodegenerative diseases.

Enhanced electrochemical performance of flexible carbon substrates via carbonized layer of oxidant-induced polydopamine for high-performance supercapacitors

Flexible substrates are essential for advancing energy storage materials in portable and wearable devices. Carbon cloth is a promising option due to its flexibility and lightweight properties, but its high electrical resistance and hydrophobic surface present challenges for solution-based electrolytes. To overcome these issues, a surface modification technique was developed that coats carbon cloth with dopamine and subsequently carbonizes it. This process enhances hydrophilicity while preserving the sp2 carbon structure, significantly improving electrical conductivity. The chemical bath deposition of Ni(OH)2 onto the carbonized polydopamine-coated carbon cloth produced a uniform layer that increased specific capacitance dramatically. At a current density of 1 A/g, the specific capacitance reached 1100F/g, compared to 919F/g for Ni(OH)2 on unmodified carbon cloth. Furthermore, the electrodes maintained high specific capacitance at higher current densities, showcasing superior rate capability. Overall, carbonized polydopamine layers effectively reduce electrical resistivity and hydrophobicity, enhancing the performance of carbon-based materials for energy storage applications.

Bifurcate migration of neutrally buoyant particles in unilateral slippery channel flows

As an important technique for manipulating particles in fluid–solid channel flows, inertial focusing encourages the design of the channel geometry to enhance particle radial aggregation. Traditional methods typically use exquisite sheathes or elbows to create constricted flows, which ultimately increase flow resistance and lower fluid–solid separation efficiency. This paper presents a slippery wall modification technique that, by regulating the channel flows, is expected to induce nontrivial particle lateral migrations. More specifically, interface-resolved simulations are performed using the lattice Boltzmann method. A slip boundary condition is applied to the redesigned hydrophobic bottom wall. It is observed that the typical bifurcate migration, i.e., particles moving divergently toward the upper and lower equilibrium positions around a crucial location (CL), does not occur along the channel centerline. The CL is always below the centerline, and it decreases consistently with an increase in Kn or Re. By increasing Re, particles are prone to approach the channel centerline. With larger Kn, particles in the higher equilibrium position are affected in the same way, but their lower counterparts are drawn to the bottom wall.

Polydopamine-modified 3D flower-like ZnMoO4 integrated MXene-based label-free electrochemical immunosensor for the food-borne pathogen Listeria Monocytogenes detection in milk and seafood

Listeria monocytogenes is a gram-positive bacterium that causes listeriosis in humans. This contaminates the ready-to-eat food products and compromises their safety. Thus, detecting its presence in food samples with high sensitivity and reliability is necessary. Herein, we propose a label-free electrochemical immunosensor based on a mussel-inspired polydopamine-modified zinc molybdate/MXene (PDA@ZnMoO4/MXene) composite for effective and rapid detection of L. monocytogenes in food products. Spectrophotometry approaches were employed to examine the resulting composites. Voltammetry and impedimetry techniques were used to confirm the step-by-step assembly of the immunosensor and its sensitive detection of L. monocytogenes in various food products, such as milk and smoked seafood. The results demonstrated the practicality of the constructed immunosensor, with an appreciable linearity of 10–107 CFU/ ml and a reasonably low detection limit (LOD, 12 CFU/ml). Moreover, the immunosensor exhibited excellent selectivity for microbial cocktails and acceptable repeatability, reproducibility, and storage stability. Thus, we believe that the proposed sensitive, reliable, and label-free immunosensor based on the PDA surface modification technique for detecting L. monocytogenes can be extended to monitor various food-borne pathogens to ensure food safety.

Reversible silicon anodes enabled by fluorinated inorganic-organic hybrid coating

Silicon anodes deliver batteries with energy densities much higher than those based on today’s dominant graphite anodes. However, they commonly exhibit huge volume variations and unfavorable interface stability, causing a gradually diminishing capacity on extended cycling. Most Si-based batteries consisting Si/C composites in industry can only use a very limited amount of Si (<30 % by weight). Exploiting molecular layer deposition (MLD) technique, a fluorine-rich flexible inorganic–organic hybrid alucone (AlFHQ) shell is controllably deposited onto Si electrodes. Employing ex situ XPS and AFM, the AlFHQ film presents reversible electrochemical evolutions in terms of composition and morphology. The interactions the between Li+ and −O−2,3,5,6-fluorobenzene functional groups help to construct a mechanically-chemically robust LiF-rich hybrid solid electrolyte interphase (SEI) on Si anode, delivering enhanced interfacial stability and integrity of electrode. An optimized coating thickness (≈5 nm) for interfacial stabilization and Li+ transport kinetics is demonstrated, namely, Si@AlFHQ-20. The reported fluorine-rich hybrid modification technique endows (a), stable cycling of Si anode (≈3.8 mAh cm−2) with an ultrahigh initial Coulombic efficiency (ICE) of 92.3 %; (b), enhanced rate capability of 1468 mAh/g at 2.0 A g−1 and good cycling performance; and (c), overall cell (Si@AlFHQ-20//LiCoO2@Al2O3) operational stability for more than 100 cycles under stringent cathode conditions (2.68 mAh cm−2, high cutoff voltage at 4.55 V).

LITERATUR STUDI MENGENAI ADSORBEN LIMBAH CANGKANG HEWAN LAUT DALAM BERBAGAI KEILMUAN

The utilization of marine animal waste as a base material for adsorbents has become an increasingly popular research topic across various scientific fields, including chemistry, environmental science, and materials science. Waste from marine animals, such as crab shells, oyster shell, seashell, and shrimp shell, possesses high potential to be processed into adsorbents due to their abundant calcium carbonate, chitosan, and protein content. The use of this waste as adsorbents not only provides a solution to environmental issues related to the accumulation of organic waste but also offers cheaper and eco-friendly alternative for water treatment, air purification, and contaminated soil remediation. Research has shown that marine animal waste-based adsorbents are effective in removing various pollutants, including heavy metals, textile dyes, and hazardous organic compounds. With specific modification techniques, the performance of these adsorbents can be enhanced, making them competitive with commercial adsorbents. Overall, the use of marine animal waste as adsorbents represents an innovative approach that contributes to waste reduction and the enhancement of environmental sustainability.

REVIEW OF LITERATURE ON NANOSCALE TOPOGRAPHIC MODIFICATION, MAGNETIC NANOPARTICLES, AND THEIR ROLES IN OSSEOINTEGRATION AND BONE TISSUE ENGINEERING

Here, we will review together the roles of nanoscale modification of titanium substrates and use of magnetic nanoparticles in osseointegration and bone tissue engineering. The technological advances in nanotechnology that has been achieved create new measures to increase the implants-biological systems for an optimal osseointegration through improving important cell-specific functions. We systematically review nanoscale surface modification techniques of titanium implants, covering their physicochemical properties, influence on cellular behaviors and clinical relevances. The report also lengthy discusses the clinical applicability of magnetic nanoparticles for drug and gene delivery systems, targeted cancer therapy as well bone tissue engineering regulting their intrinsic superparamagnetism properites, biocompatibility with other therapies etc. We present detailed review of these technologies and their potential applications in clinical settings.