Stirring Duration Research Articles

Reclamation of Aged Transformer Oil Employing Combined Adsorbents Techniques Using Response Surface for Transformer Applications

The study lowers the environmental risk by combining biodegradable adsorbents with stronger adsorption. This work uses two distinct kinds of adsorbents, namely Polyaniline (PANI) coated Kappa Cotton (KPC) and activated clay-biopolymer, Bentonite (aB) composite and Chitosan (CTN), to recover the aged transformer oil (aTO). Using the Box-Behnken (BB) design paired response surface method (RSM) approach, an experimental sequence was created to determine the optimal ratio of the adsorbent materials. The aTO was supplemented with the homogenized aB-CTN material (A*) and PANI-coated-KPC (B*) materials. After optimization, it was found that the optimal values for the input variables for the dielectric breakdown voltage and dielectric dissipation factor were A* = 1.76 g, B* = 1.28 g, temperature = 78.9 °C, while stirring duration = 3 h was kept constant. After treatment under ideal conditions, it was found that aTO1 had dielectric characteristics of 46.6 kV and 0.0020 dissipation factor, which are equivalent to those of laboratory studies conducted in triplicate with a 2.5 percent error. They demonstrate that aTO exhibits an outstanding dielectric response when the optimal proportion of the process variables (A* and B*) is used. The removal of impurities from aTO has considerably enhanced its dielectric properties, as seen by the CIE chromaticity coordinates, XRD analysis, UV responses, and FTIR analyses. The material’s ability to sorb dyes, polar impurities, and heavy metal ions is significantly increased by the expanded active sites of A* and B*.

Analysis and Optimization of Machinability of Al<sub>2</sub>O<sub>3</sub> and Fly Ash Reinforced Aluminum Hybrid Composites Using Carbide Inserts

Aluminum matrix hybrid composites reveal excellent mechanical behavior compared to traditional materials for a wide range of conditions and applications. However, the machining of this kind of composite is a challenging job due to its improved mechanical hardness. The problems faced during the cutting of these composites are increased machining forces, poor surface quality, and increased tool wear. Many types of research are still in progress across the world to overcome these issues by using a variety of inserts and processing constraints. So, this paper is mainly focused on the study of the machinability of aluminum hybrid composites. The composites are synthesized by employing stir casting via varying the filler content, stirring duration, and speed. The fabricated composites are machined using coated and uncoated carbide inserts. Machining forces, surface roughness, and insert wear are assessed to learn the machinability of these materials by varying the machining constraints. Taguchi analysis was employed to assess the effect of the constraints on the retorts. Keywords. Aluminum Hybrid Composites, Stir Casting, Machinability, Taguchi Analysis.

Taguchi optimization and modelling of stir casting process parameters on the percentage elongation of aluminium, pumice and carbonated coal composite

Aluminium matrix composites, which are a subclass of metal matrix composites, have characteristics including low density, high stiffness and strength, better wear resistance, controlled thermal expansion, greater fatigue resistance, and improved stability at high temperatures. The scientific and industrial communities are interested in these composites because they may be used to manufacture a broad variety of components for cutting-edge applications. This has study observed how the stirring speed, processing temperature, and stirring duration of the stir casting process affected the percentage elongation of Al-Pumice (PP)-Carbonized Coal Particles (CCP) hybrid composites. It also looked at the optimal weight of these natural ceramic reinforcements using the Taguchi optimization technique. While optimizing the percentage elongation property, the hard compound such as silica, iron oxide, and alumina, were discovered during the characterisation of the reinforcement, showing that PP and CCP can be used as reinforcement in metal matrix composite. The percentage of elongation of the hybrid composite was shown to be most affected by the PP, followed by processing temperature, stirring speed, CCP, and stirring time, using stir casting process parameter optimization. It was observed at 2.5 wt% of pumice particles, 2.5 wt% of carbonated coal particles, 700 °C processing temperature, 200 rpm stirring speed, and 5 min stirring time, the optimum percentage of elongation was discovered to be 5.6%, which is 25.43% lower than the percentage elongation of Al-alloy without reinforcing. The regression study developed a predictive mathematical model for the percentage elongation (PE) as a function of the stir casting process parameters and offered a high degree of prediction, with R-Square, R-Square (adj), and R-Square (pred) values of 91.60%, 87.41%, and 79.32% respectively.

Reproduction of Nanofluid Synthesis, Thermal Properties and Experiments in Engineering: A Research Paradigm Shift

The suspension of different nanoparticles into various conventional thermal fluids to synthesize nanofluids has been proven to possess superior thermal, optical, tribological, and convective properties, and the heat transfer performance over conventional thermal fluids. This task appears trivial but is complicated and significant to nanofluid synthesis and its subsequent utilization in diverse applications. The stability of mono and hybrid nanofluids is significantly related to stirring duration and speed; volume, density, and base fluid type; weight/volume concentration, density, nano-size, and type of mono or hybrid nanoparticles used; type and weight of surfactant used; and sonication time, frequency, mode, and amplitude. The effects of these parameters on stability consequently affect the thermal, optical, tribological, and convective properties, and the heat transfer performance of nanofluids in various applications, leading to divergent, inaccurate, and suspicious results. Disparities in results have inundated the public domain in this regard. Thus, this study utilized published works in the public domain to highlight the trend in mono or hybrid nanofluid formulation presently documented as the norm, with the possibility of changing the status quo. With the huge progress made in this research area in which a large quantum of different nanoparticles, base fluids, and surfactants have been deployed and more are still emerging in the application of these advanced thermal fluids in diverse areas, there is a need for conformity and better accuracy of results. Reproduction of results of stability, thermal, optical, tribological, anti-wear, and fuel properties; photothermal conversion; and supercooling, lubrication, engine, combustion, emission, thermo-hydraulic, and heat transfer performances of formulated mono or hybrid nanofluids are possible through the optimization and detailed documentation of applicable nanofluid preparation parameters (stirring time and speed, sonication duration, amplitude, mode, frequency, and surfactant concentration) employed in formulating mono or hybrid nanofluids. This proposed approach is expected to project a new frontier in nanofluid research and serve as a veritable working guide to the nanofluid research community.

Influence of Preparation Characteristics on Stability, Properties, and Performance of Mono- and Hybrid Nanofluids: Current and Future Perspective

Nanofluids (NFs) synthesized via the suspension of diverse nanoparticles into conventional thermal fluids are known to exhibit better thermal, optical, tribological, and convective properties, photothermal conversion, and heat transfer performance in comparison with traditional thermal fluids. Stability is pivotal to NF preparation, properties, performance, and application. NF preparation is not as easy as it appears, but complex in that obtaining a stable NF comes with the harnessing of different preparation parameters. These parameters include stirring duration and speed, volume, density, base fluid type, weight/volume concentration, density, nano-size, type of mono or hybrid nanoparticles used, type and quantity of surfactant used, and sonication time, temperature, mode, frequency, and amplitude. The effect of these preparation parameters on the stability of mono and hybrid NFs consequently affects the thermal, optical, rheological, and convective properties, and photothermal conversion and heat transfer performances of NFs in various applications. A comprehensive overview of the influence of these preparation characteristics on the thermal, optical, rheological, and properties, photothermal conversion, and heat transfer performance is presented in this paper. This is imperative due to the extensive study on mono and hybrid NFs and their acceptance as advanced thermal fluids along with the critical importance of stability to their properties and performance. The various preparation, characterization, and stability methods deployed in NF studies have been compiled and discussed herein. In addition, the effect of the various preparation characteristics on the properties (thermal, optical, rheological, and convective), photothermal conversion, and heat transfer performances of mono and hybrid NFs have been reviewed. The need to achieve optimum stability of NFs by optimizing the preparation characteristics is observed to be critical to the obtained results for the properties, photothermal conversion, and heat transfer performance studies. As noticed that the preparation characteristics data are not detailed in most of the published works and thus making it mostly impossible to reproduce NF experimental studies, stability, and results; future research is expected to address this gap. In addition, the research community should be concerned about the aging and reusability of NFs (mono and hybrid) in the nearest future.

Multi-Performance Optimization of the Mechanical Characteristics of Basalt Fiber and Silicon Carbide-Filled Aluminum Matrix Composites

In the existing state, aluminum metal matrix composites (AlMMCs) are a category of materials that have successfully fulfilled the majority of demanding requirements in applications where moderate strength, high stiffness, and lightweight are necessary. This paper is focused on processing aluminum hybrid composites by reinforcing the aluminum alloy with a novel combination of fillers: basalt fibers and silicon carbide via stir casting. The main aim is to study the impact of processing conditions on the properties of the developed composite. Nine samples are produced by varying the reinforcement content, stirring rate, and duration based on the L9 Taguchi Array. SEM analysis is utilized to examine the microstructure of the developed composites. The samples were also machined and tested for their mechanical, physical, and wear behavior as per ASTM standards. The maximum density and hardness of 2883.3 kg/m3 and 45.6 HRB, respectively, are observed at higher filler content conditions. In contrast, the minimum specific wear rate, maximum ultimate tensile, and impact strength of 1.86·10–5 mm3/(N·m), 263.5 MPa, and 93 N/mm are observed in higher stirring duration conditions. So, to avoid conflicting combinations of optimal input factors, grey relational analysis (GRA) tied with principle component analysis (PCA) is employed to determine the multi-objective performance parameter and the optimal combination of input factors for better response. Confirmatory tests were also performed to verify and validate the same. ANOVA analysis is also utilized to assess the significance of the process parameters on the responses.

A Promising Ultra-Small Unilamellar Carrier System for Enhanced Skin Delivery of α-Mangostin as an Anti-Age-Spot Serum.

If it can be effectively delivered to its site of action, α-mangostin has potential in development of novel cosmeceuticals due to its melanogenesis-blocking activity. The aim of this study was to develop an ultra-small unilamellar carrier system for α-mangostin and to evaluate its effect as an anti-age-spot serum on humans in vivo. The ultra-small unilamellar carrier bases were optimized using a 25 factorial design, with five factors (virgin coconut oil, soy lecithin, Tween 80, and stirring duration and speed) and two levels (low and high); response of droplet size was analyzed using Design Expert 12®. The anti-spot examination was conducted via capturing digital images of the human skin after topical application of an α-mangostin-loaded ultra-small unilamellar carrier at night for two consecutive weeks. The results thereof were analyzed using Motic Live Imaging 3.0 and a standard red, green, and blue score. The optimized serum formula was confirmed with a composition of 2.3% virgin coconut oil, 1% lecithin, and 28.3% Tween 80 (polysorbate 80) at a stirring speed of 1500 revolutions per minute for 15 min. Incorporation of 3% α-mangostin to the optimized base formula produced an ultra-small unilamellar carrier globule size of 16.5 nm, with zeta potential of −25.8 mV and a polydispersion index of 0.445. Physical characterization of an α-mangostin-loaded ultra-small unilamellar carrier comprised 90.94% transmittance, a pH value of 6.5, a viscosity of 38 cP, specific gravity of 1.042 g/mL and 72.46% entrapment efficiency. A transmission electron microscope confirmed spherical nanosized droplets in the system. Topical application of an α-mangostin-loaded ultra-small unilamellar carrier at night for 2 consecutive weeks demonstrated anti-age-spot activity shown through a significant reduction in intensity and area of spots in human volunteers (p < 0.05).

Influence of alkali metals on water dynamics inside imidazolium-based ionic liquid nano-domains.

The global need to expand the design of energy-storage devices led to the investigation of alkali metal - Ionic Liquid (IL) mixtures as a possible class of electrolytes. In this study, 1D and 2D Nuclear Magnetic Resonance (NMR) and Electrochemical Impedance Spectroscopy (EIS) as well as Molecular Dynamics (MD) simulations were used to study the intermolecular interactions in imidazolium-based IL - water - alkali halide ternary mixtures. The 1H and 23Na 1D and 1H DOSY NMR spectra revealed that the presence of small quantities of NaCl does not influence the aggregation of water molecules in the IL nano-domains. The order of adding ionic compounds to water, as well as the certain water and NaCl molecular ratios, lead to the formation of isolated water clusters. Two ternary solutions representing different orders of compounds mixing (H2O+ IL + NaCl or H2O+ NaCl + IL) showed a strong dependence of the initial solvation shell of Na+ and the self-clustering of water. Furthermore, the behaviour of water was found to be independent from the conditions applied during the solution preparation, such as temperature and/or duration of stirring and aging. These findings could be confirmed by large differences in the amount of ionic species, observed in the ternary solutions and depending on the order of mixing/solute preparation.

In-situ immobilization cobalt-based metal-organic frameworks nanosheets on carbon composites for supercapacitors

The Ni-alanine complex was calcined under a high-temperature nitrogen environment after being synthesized at room temperature. The Ni/C precursors carrying nickel nanoparticles were obtained. A series of composites with different times of stirring (CoMOF@Ni/C) were prepared by in-situ growth of CoMOF on Ni/C precursors. Various electrochemical measurement technologies helps us analyze the potential of CoMOF@Ni/C composites for supercapacitors. Thereinto, CoMOF@Ni/C with a stirring duration of 12 h (denoted as F-12) reached a maximal specific capacitance of 27.73 mAh g−1, and an 84.1 % coulombic efficiency. Meanwhile, the F-12//AC aqueous device was created with a cycling feature that only showed 8 % decay. This method of MOFs in situ immobilization not only prevents the excessive aggregation of Ni nanoparticles in the Ni/C precursor, but also provides more electrolyte contact area. Therefore, mass transfer and electron transfer can be facilitated throughout the electrochemical process. Simultaneously, the stability and conductivity of carbon substrates obtained from the calcination in a nitrogen atmosphere could effectively make up for the shortage of pure MOFs.

Development of Dapagliflozin Solid Lipid Nanoparticles as a Novel Carrier for Oral Delivery: Statistical Design, Optimization, In-Vitro and In-Vivo Characterization, and Evaluation.

Controlling hyperglycemia and avoiding glucose reabsorption are significant goals in type 2 diabetes treatments. Among the numerous modes of medication administration, the oral route is the most common. Introduction: Dapagliflozin is an oral hypoglycemic agent and a powerful, competitive, reversible, highly selective, and orally active human SGLT2 inhibitor. Dapagliflozin-loaded solid lipid nanoparticles (SLNs) are the focus of our present investigation. Controlled-release lipid nanocarriers were formulated by integrating them into lipid nanocarriers. The nanoparticle size and lipid utilized for formulation help to regulate the release of pharmaceuticals over some time. Dapagliflozin-loaded nanoparticles were formulated by hot homogenization followed by ultra-sonication. The morphology and physicochemical properties of dapagliflozin-SLNs have been characterized using various techniques. The optimized dapagliflozin-SLNs have a particle size ranging from 100.13 ± 7.2 to 399.08 ± 2.4 nm with 68.26 ± 0.2 to 94.46 ± 0.7% entrapment efficiency (%EE). Dapagliflozin-SLNs were optimized using a three-factor, three-level Box–Behnken design (BBD). Polymer concentration (X1), surfactant concentration (X2), and stirring duration (X3) were chosen as independent factors, whereas %EE, cumulative drug release (%CDR), and particle size were selected as dependent variables. Interactions between drug substances and polymers were studied using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and atomic force microscopy (AFM) analysis indicated the crystalline change from the drug to the amorphous crystal. Electron microscope studies revealed that the SLNs’ structure is nearly perfectly round. It is evident from the findings that dapagliflozin-SLNs could lower elevated blood glucose levels to normal in STZ-induced diabetic rats, demonstrating a better hypoglycemic impact on type 2 diabetic patients. The in vivo pharmacokinetic parameters of SLNs exhibited a significant rise in Cmax (1258.37 ± 1.21 mcg/mL), AUC (5247.04 mcg/mL), and oral absorption (2-fold) of the drug compared to the marketed formulation in the Sprague Dawley rats.

Influence of mass concentration, cement-to-tailings ratio, and stirring duration on the strength of CPB considering pore characteristics

Influence of mass concentration, cement-to-tailings ratio, and stirring duration on the strength of CPB considering pore characteristics

STABILITAS NANOSTRUCTURED LIPID CARRIER COENZYME Q10 DENGAN VARIASI WAKTU PENGADUKAN

ABSTRACTCoenzyme Q10 (Co-Q10) or Ubiquinone is an antioxidant that is unstable to light and is highly lipophilic causing instability during storage, so a Nanostructured Lipid Carrier (NLC) delivery system is needed that can improve stability. The manufacture of NLC uses the emulsification method by melting two types of lipids, namely solid lipid cetyl palmitate and liquid lipid alpha tocopherol with the help of stirring using a magnetic stirrer. The purpose of this study was to determine the characteristics and stability of NLC Co-Q10 at various stirring times. The results of testing the characteristics NLC Co-Q10, that stirring for 6 and 9 minutes, obtained pH values of 6,64 and 6,62 with particle sizes of 215.03 nm and 188.25 nm, the entrapment efficiency values were 75.57% and 77.96%, respectively. Increasing the speed and duration of stirring in the manufacture of the NLC Co-Q10 system will obtain high trapping efficiency values and be more stable in storage at room temperature for 28 days.Keywords: coenzyme Q10, emulsification, nanostructured lipid carriers, stability.

Preparation of Moisturizing Lotion Containing Silkworm (Bombyx mori L.) Sericin Nanoparticles

Sericin as one of two main proteins in silkworm (Bombyx mori L.) cocoons was found to have the ability to increase skin moisture in cosmetics. The objective of this study was to determine the optimal formula of sericin nanoparticle lotion and the effectiveness of sericin nanoparticle lotion. The formation of sericin nanoparticles was mainly carried out by mixing and stirring mechanism using urea as a crosslinking agent. Temperature and stirring speed were fixed, while stirring duration were varied. Optimal sericin nanoparticles with the average particle size of 701 nm were obtained at 800 rpm stirring for 30 minutes at room temperature. Sericin nanoparticles lotion was then formulated with 5% and 10% sericin nanoparticles. Results showed that lotion containing 5% and 10% sericin nanoparticles significantly increase skin moisture.Keywords: moisturizer, lotion, silkworm, sericin, nanoparticles

Effect of 3-aminopropyltriethoxysilane on the formation of 45S5 bioactive glass microspheres

45S5 bioactive glass microspheres (BGMs) is a material that has been receiving extensive interest in biomedical application as bone tissue restoration, craniofacial surgery, dental implant coating, and drug delivery because of their advantages in pore dimension, encapsulation network, interconnectivity as well as the controllable particle size. The common method to produce BGMS is flame synthesis and sol–gel derivation where the random size or time-consuming have become the significant drawbacks of these methods. Hence in this work, a faster alternative two-step method, melt quenching followed by Pickering emulsion has been adopted. There are two manipulatable variable which is the amount of 3-aminopropyltriethoxysilane (APTES) (3/5/7 wt%) and the stirring duration (1/2/3 h) to determine their effects on particle size of BGMs. The incorporation of APTES as surfactant is to improve the hydrophobicity of the silica particles. The emulsion system is comprised of a water–oil interface with ratio 6:4. The characterizations involved for bioactive glass (BG) and BGMs are X-ray Diffraction (XRD), Fourier Transform Infrared Ray Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and dissolution test. The results showed that the surface modification by APTES is successful, and the BGMs specimen synthesized with 5 wt% APTES and 2 h stirring duration has the smallest particle size (232.031 µm) with almost spherical shape as well as the best dissolution properties.

Fabrication and characterization of magnesium hybrid composites

Lightweight magnesium-based constituents are acquiring an extensive assortment of uses owing to their improved properties and behavior. Hybrid development of these materials can still further advance these characteristics. Rigorous exploration in the arena of cutting-edge lightweight composites is more concentrated nowadays. Accordingly, labors were made to alter the prevailing development trials to advance the competence of the prevailing composites and to analyze the effect of handing out constrictions on the characterization of the composites. So, the main objective of this paper is to focus on the production and characterization of magnesium amalgam composites by filling graphite and silicon carbide in the base metal. The composites were developed by altering the filler content, stirring duration, and speed according to the Taguchi array. Four samples were fabricated accordingly by employing the stir casting technique. The morphology of the dispersions of the developed composites was analyzed using an optical microscope and mechanical and physical behavior like hardness, density, wear, and tensile tests were performed on the developed samples. Taguchi analysis was employed to study and optimize the upshot of the processing constraints on the behavior of the same. The maximum hardness value of 55.4Hv, the density of 1.943 g/cm3, and UTS of 200 N/mm2 are detected at the optimized parametric constraints of the process through S/N plots via Taguchi Analysis.

OPTIMIZATION OF DILTIAZEM HYDROCHLORIDE NANOPARTICLES FORMULA AND ITS RELEASE KINETICS EVALUATION

Objective: The purpose of this study was to determine the optimum formula of diltiazem HCl-loaded chitosan nanoparticles due to variations in the speed and duration of stirring and evaluating the release kinetics in vitro using DDSolver.&#x0D; Methods: The method used to prepare nanoparticles is ionic gelation. The ionic gelation method involves an ionic cross-linking between cations on the backbone of chitosan and anion, such as sodium tripolyphosphate (Na TPP). &#x0D; Results: Stirring speed of 1200 rpm and stirring time of 2 h produce an optimum response. The optimum formula has an entrapment efficiency of 71.10%, a particle size of 110.2 nm, and a polydispersity index of 0.268. The dry powder of diltiazem HCl nanoparticles produced a drug loading of 66.14±1.71% and a yield of 34.07±0.73%. The FT-IR showed ionic interaction (cross-linking) between ammonium ions from chitosan and phosphate ions from Na TPP. Scanning electron microscopy (SEM) analysis showed a particle size of 150 µm, a spherical shape, and rough surface morphology. In vitro release profiles indicated prolonged release, which follows the Korsmeyer Peppas model. &#x0D; Conclusion: It can be concluded that increasing the speed and duration of stirring will improve drug entrapment and reduce the particles size variation. The dry nanoparticles release mechanism is by diffusion and matrix erosion.

Karakteristik Mikroemulsi a-Tokoferol pada Perbandingan Campuran Tiga Surfaktan Nonionik dan Lama Pengadukan

Microemulsions have thermodynamics and stable kinetics as carriers of ?-tocopherol compounds. This study aimed to know the effect of mixtures ratio of three nonionic surfactants and stiring time on the characteristics of ?-tocopherol microemulsion, as well as to obtain the best stiring time and mixture ratio of three nonionic surfactants to produce ?-tocopherol microemulsion. This experiment used a randomized block design with two factors. The first factor is the ratio of a mixture of three nonionic surfactants with Hydrophilic-Lipophilic Balance (HLB) 14.5. The second factor is stirring time. Data were analyzed using analysis of variance and continued with BNJ test. Test the effectiveness index to determine the best treatment. The results showed that the comparison of three surfactant mixtures, stirring duration and interaction between treatments significantly affected the characteristics of ?-tocopherol microemulsion. Comparison of the mixture of three surfactants Tween 80: Span 80: Tween 20 (v / v%) HLB 14.5 consisting of F2 (89,5 : 5,5 : 5) and 4 minutes stirring time is the best treatment for the characteristics of ?-Tocopherol microemulsion. The best treatment has the characteristics of ?-tocopherol microemulsions namely transparent appearance, stable to centrifugation (4500 rpm), pH (4.5; 5.5 and 6.5) and dilution (1: 9, 1:49 and 1:99) with Turbidity index values ??are below 1 percent. Microemulsion turbidity index values ??before and after centrifugation were 0.19 percent and microemulsion turbidity at pH 4.5 and 1: 9 dilution were 0.11 percent.&#x0D; Keywords: microemulsion, stirring time, surfactan non ionic, ?-Tocoferol

Effects of Stirring Duration and Casting Temperature in Ultrasonic Assisted Stir Casting of Al A356 Matrix Composites

In the present study, two main parameters as stirring duration and casting temperature were taken into consideration in order to determine the effect of stirring process on mechanical properties of aluminum matrix composites. AlSi7Mg0.3 aluminum alloy and silicon carbide (SiC) particles were used as matrix and reinforcement materials to produce composite samples. Firstly, stirring processes were applied as the combination of mechanical stirring and ultrasonic vibration for the various time as 3-1, 2-2 and 1-3 minutes, respectively. To determine the effect of stirring process, tensile tests were applied to whole samples and Quality Indexes (QI) were calculated by using the results of tensile tests. According to the values of QI, the produced samples with the combination of 1 minute mechanical stirring and 3 minutes ultrasonic vibration showed the maximum mechanical properties. Afterwards, the determined stirring combination was chosen to specify the appropriate molten metal temperature. Three different casting temperatures were addressed as 700˚C, 720˚C and 740˚C. According to mechanical tests results and calculations of QI and metallographic analysis, the maximum mechanical properties were obtained with aluminum composite reinforced with 1 wt. % SiC at 720˚C molten metal temperature by applying 1 minute mechanical stirring and 3 minutes ultrasonic vibration.

The Utilization of Sugarcane Bagasse to Remove Cr (VI) Heavy Metal Waste with Adsorption

Sugarcane bagasse obtained from sugar factories is the residue that is usually left behind and considereduseless. In fact, sugarcane bagasse can be made nanopore-activated carbon in the form of powder and tablet,which is effective as adsorbent of Cr (VI) in heavy metal waste pollution. The production in this studystarted from drying using sunlight, crushing sugarcane bagasse into powder, carbonizing the powder at 3000C, activating it using HCL5N, sieving with 200 mesh and sonicating in 15 minutes with 40% amplitude.After accomplishing those steps, nanopore powder was obtained and then pressed into a tablet. Absorptioncapacity testing of Cr (VI) heavy metal was performed with an artificial sample using K2Cr2O7 solution.Sugarcane bagasse nanopore powder was tested for its contact time by adding 0.1 gram of nanopore powderinto the sample solution, leaving the sample for a while, and analyzing the sample using spectrophotometry.The results show that the optimum contact time of nanopore powder was six hours to reduce 91.80% of Cr(VI) level and the optimum contact time of the tablet was five hours to remove 56.35% of Cr (VI). Testingon a fixed variable of 105 rpm stirring speed and various contact times produced an optimum result with90 minutes stirring duration and adsorption capacity of 91.80% for removing Cr (VI). Examination onfixed variable of stirring time and independent variable of stirring speed resulted in an optimum adsorptioncapacity of 90.07% in Cr (VI) removal, with 105 rpm stirring speed. This study concludes that powder hada greater adsorption capacity than a tablet, while the tablet was more practical for usage.

Sol-Gel-Derived Bioactive and Antibacterial Multi-Component Thin Films by the Spin-Coating Technique.

Although metallic alloys commonly used as prosthetics are durable and mechanically strong, they are often bioinert and lack antibacterial properties. Implementing a bioactive glass material with antibacterial properties as a coating on a metallic substrate provides mechanical strength and bioactivity, as well as antibacterial properties. Many coating methods have been extensively investigated; however, most of them can be expensive, are difficult to scale up, or do not form thin films, which could prevent their translation to clinical practice. The formation of thin films by spin-coating multi-component solution-gelation (sol-gel)-derived glass with antibacterial and bioactive properties has not been achieved previously. For this study, stainless steel 316L substrates were spin-coated with a sol-gel-derived bioactive and antibacterial glass coating in SiO258.3-P2O57.1-CaO25.6-Al2O55.4-Ag2O2.1-Na2O1.5 wt% system (Ag-BG). A sol-gel processing condition that avoids elemental separation upon spin-coating when sintering happens at below the calcination temperature (500 °C) has been developed. This work demonstrates that silver reduction occurs when the concentrations of other cations such as Ca2+ and Na+ in the solution increase. Increasing the stirring duration time prior to the increase of cations, Ag+ ions are stabilized by aluminum tetrahedra, and their reduction to metallic silver does not occur. This study also shows that large dilution ratios (water:tetraethyl orthosilicate) greater than 25:1, accompanied by long stirring durations, produce morphologically homogeneous coatings. Using this strategy, thin films were formed with antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) biofilm and biological responses that promote eukaryotic cell adhesion and proliferation. In total, the improved synthesis strategy opens new avenues for the development of novel bioactive and antibacterial thin-film coatings, as it reveals the processing characteristics that control the physicochemical and morphological properties of the formed films.