Magnetic Mixer Research Articles

Investigation of the Effect of TiO2 Nanoparticles on Engine Performance and Emission Characteristics in Diesel Engines

This study aimed to examine the changes in performance and emission values in a four-stroke and three-cylinder diesel engine by using pure diesel fuel and fuels created by adding TiO2 nanoparticles. Adding TiO2 nanoparticles to the fuel aimed to improve the combustion characteristics of the diesel engine and reduce the harmful effects of exhaust emissions. Pure diesel and TiO2 nanoparticle added fuel samples in three distinct amounts, 25 ppm, 50 ppm, and 75 ppm, were prepared in magnetic and ultrasonic mixers as D100, D100+25TiO2, D100+50TiO2, and D100+75TiO2. All fuel samples used in the research were tested at a constant speed of 1800 revolutions per minute (rpm) at 25%, 50%, 75%, and 100% full loads. When TiO2-added fuels were compared to pure diesel, there was a 15.12% rise in brake thermal efficiency at %25 load and a 13.36% drop in brake specification fuel consumption at %25 load. EGT values also increased with the increase in load and adding TİO2. The amount of CO2 in exhaust emissions increased by 5% at maximum load in the fuel with the highest TiO2 additive according to neat diesel. There was an average increase of 11.44% in NOX emissions for all loads with TiO2 addition. The results show that the fuel mixture created by adding TiO2 nanoparticles can be used in certain proportions in diesel engines and that the TiO2 addition positively improves the combustion properties, engine performance, and exhaust gas emissions.

A Sustainable Bio-Filler for Epoxy Composites: Use of Pistachio Shell Powder

The use of natural materials has become a crucial concern for humanity due to the limited quantity of petroleum-based products and their harmful impact on nature. The use of natural materials is inevitable for a greener and more sustainable world. Transforming agricultural industrial waste into a high-value product or a source of fuel can significantly benefit our country's economy and environment. Pistachio shell is one of the agro-industrial wastes and is abundant in our country. Our country can benefit economically and environmentally by utilizing and repurposing discarded shells, whether as fuel or as a valuable commodity. In this study, the shells of pistachios grown in Şanlıurfa were crushed in a stone mortar and reduced to certain sizes and turned into powder. Later, this powder was used as a bio-filler material for epoxy resin. Powders were used at 1% and 2% additive ratios and homogeneous mixing was carried out using both magnetic and ultrasonic mixers. The mechanical properties of the obtained biofilled epoxies were investigated and their microstructures were analyzed. Tensile test, bending test and hardness test were performed as mechanical tests and densities were measured. An improvement of 8% and 15% was detected in the maximum tensile and bending strength, respectively. The hardness and density values also increased by 8% and 1.7%, respectively. As a result of the microstructure analysis, no air bubbles were formed in the samples and no agglomeration occurred. Obtained results revealed that pistachio shell grown in Şanlıurfa can be used as bio-filler material.

Green Synthesis of Bioconjugated Magnetic Nanoparticles (MNPs) By Punica granatum And Its Applications As Anti-microbial Agent

Abstract Introduction In recent years, the development of efficient green chemistry methods for synthesizing metal nanoparticles has become a major focus of many researchers. Nanoparticles produced by plants are more stable, and the rate of synthesis is faster than in the case of microorganisms. Methods/Case Report Objectives: Synthesis of (MNPs) by Punica granatum, confirming the formation that it exists, and studying their antibacterial activity effects. Materials and methods By using the Pomegranate plant, drying the plant 200 g (hot oven/sun), grinding the plant (powder form), dissolving in methanol 800 ml, leaving it overnight, filtration with filter paper, then collecting the filtrate, and adding equal volumes of iron solution in a beaker. We observed color change due to nanoparticle formation. By using UV - visible spectroscopy, we proved the presence of nanoparticles manufactured using pomegranate. After that, we studied its antibacterial effect by using several concentrations to determine the least effective (MIC) concentration against the bacteria Staphylococcus aureus on Mueler Hinton agar media. Results (if a Case Study enter NA) The nanoparticles were formed strongly and remarkably, and the color quickly changed to an intense black color, even before using the magnetic mixer. The UV - visible spectroscopy characterizes the synthesized Fe3O4 (MNPs). The peak was at 410 nm, and the black color was developed to indicate the presence of (MNPs). Then we performed antibiotic testing on Staphylococcus aureus by using several concentrations. The nanoparticles were highly effective by using the full concentration and effective by using 1/2, 1/4, 1/8 concentrations. But it was inactive when the concentration was 1/16. Conclusion Nanotechnology is a modern technique to perform an accurate and reliable method for diagnosing and treating many diseases. The magnetic nanoparticles coated with the active ingredients of pomegranate extract facilitate its use the use of them as an antibacterial agent.

An Integrated Microfluidic Biosensing System Based on a Versatile Valve and Recombinase Polymerase Amplification for Rapid and Sensitive Detection of Salmonella typhimurium.

Detecting foodborne pathogens on-site is crucial for ensuring food safety, necessitating the development of rapid, cost-effective, highly sensitive, and portable devices. This paper presents an integrated microfluidic biosensing system designed for the rapid and sensitive detection of Salmonella typhimurium (S. typhimurium). The biosensing system comprises a microfluidic chip with a versatile valve, a recombinase polymerase amplification (RPA) for nucleic acid detection, and a customized real-time fluorescence detection system. The versatile valve combines the functions of an active valve and a magnetic actuation mixer, enabling on-demand mixing and controlling fluid flow. Quantitative fluorescence is processed and detected through a custom-built smartphone application. The proposed integrated microfluidic biosensing system could detect Salmonella at concentrations as low as 1.0 × 102 copies/µL within 30 min, which was consistent with the results obtained from the real-time quantitative polymerase chain reaction (qPCR) tests. With its versatile valve, this integrated microfluidic biosensing system holds significant potential for on-site detection of foodborne pathogens.

Enhancement of Oxide Coatings Quality Formed by Electrolytic Oxidation Methods on Inner Surfaces of Lengthy Products

It is known that the methods of electrolytic oxidation, including traditional anodizing and microarc oxidation, implemented according to classical schemes in electrolytic baths with mechanical, pneumatic, and magnetic mixers, cannot provide high-quality homogeneous oxide coatings on the inner surfaces of products made from valve metal alloys. In this paper, the principal possibility of obtaining high-quality uniform coatings on the extended internal surfaces of products, including the surfaces of deep holes, when an electrolyte solution is passed through them, is revealed. It has been experimentally proved that, based on the proposed approach, it is possible to process products with deep holes, achieving a ratio of both minimum and maximum values of the thickness and the breakdown voltage of coatings on the internal and external surfaces in a range of 0.85–0.93. A possibility of forming coatings exclusively on the internal surfaces of products without changing the state of their external surfaces, moreover, without using expensive electrolytic baths – inside internal cavities of products themselves, is shown. A good correlation between the values of the thickness and of the breakdown voltage of coatings has been established. As a result, a possibility of indirectly determine the coatings thickness based on the results of their breakdown voltage measuring has been substantiated.

Preparation and Evaluation of Capsules containing Standardized Extract of Wild Hawthorn (Crataegus azarolus)

Wild Hawthorn (Crataegus azarolus) is a popular medicinal plant, rich in polyphenols and flavonoids, and has been associated with many beneficial properties including anticancer, cardioprotective, and antidepressant effects. This study aimed to prepare a standardized aqueous-alcoholic extract of the deried ariel parts of C. azarolus using two different extraction methods ((Magnetic mixer (MA), and ultrasonic-assisted extraction (Us)), determine the total phenolic and flavonoid content of the obtained extracts, and compare it with the international product, and prepare capsules containing this extract to investigate the effect of different types and concentrations of disintegrating agents on the release profile of this capsules. The findings showed that the yield obtained by both extraction methods is almost the same (MA: 19.9 %, US: 18.4 %) we obtained the flavonoids of the following components (MA extract: powder of the externally marketed drug: prepared dry drug powder) used at a concentration (10 : 350: 352) mg on (36.95: 4.56: 2.299) as a percentage of flavonoids Four different formulations were filled in the hard gelatin capsules using 120 mg of the prepared extract as an active ingredient. The effect of three types of superdisintigrant (croscarmellose Sodiuom ccNa, Microcrystallin cellouse 101, Sodiuom Strach Glycolate SSG) on the dissolution rate of the active ingredient was then investigated. The study showed that the formulation without superdisintigrant released its content faster than others, but all formulations release their content after 45 min. A comparison dissolution test was performed between the Capsules containing the best formulation and the capsules containing a powder of the local Crataegus plant as well as international marketed capsules containing the powder of the Crataegus plant. The study showed that the capsules filled wih the extract released it’s content better than the other after 45 min.

Influence of the filler distribution on PDMS-graphene based nanocomposites selected properties

Insufficient homogeneity is one of the pressing problems in nanocomposites’ production as it largely impairs the properties of materials with relatively high filler concentration. Within this work, it is demonstrated how selected mixing techniques (magnetic mixer stirring, calendaring and microfluidization) affect filler distribution in poly(dimethylsiloxane)-graphene based nanocomposites and, consequently, their properties. The differences were assessed via imaging and thermal techniques, i.a. Raman spectroscopy, differential scanning calorimetry and thermogravimetry. As microfluidization proved to provide the best homogenization, it was used to prepare nanocomposites of different filler concentration, whose structural and thermal properties were investigated. The results show that the concentration of graphene significantly affects polymer chain mobility, grain sizes, defect density and cross-linking level. Both factors considered in this work considerably influence thermal stability and other features which are crucial for application in electronics, EMI shielding, thermal interface materials etc.

Magnetic field spectrum analyzer using nonlinear magnetoelectric effect in composite ferromagnet - piezoelectric heterostructure

Industrial machines and mechanisms, household appliances, natural sources and biological objects generate weak magnetic fields with amplitudes of ~10 –12 – 10 –4 T in the frequency band of ~1–10 5 Hz. Analysis of the fields’ characteristics allows to get information about internal processes and performance of these sources in a non-contact way, to carry out medical diagnostics. This makes topical the development of low-frequency magnetic field spectrum analyzers. The paper describes a spectrum analyzer of a new type using nonlinear effect of magnetic field mixing in a composite ferromagnet-piezoelectric heterostructure. The main element of the analyzer is a magnetic field mixer which contains a piezoelectric langatate single-crystal sandwiched between two layers of a magnetostrictive amorphous alloy. With simultaneous action of the measured magnetic field and the excitation magnetic field on the structure and fulfillment of the frequency matching conditions, the structure generates a voltage at the electromechanical resonance frequency. Swept-tuned spectrum analysis of the measured field is carried out by tuning the frequency of the excitation field. A prototype of the analyzer is fabricated and characterized. It operates in the frequency band of 0.1–85 kHz, has a frequency resolution of ~40 Hz, a minimum detectable field of 50 nT, and a dynamic range of 35 dB. Possibilities to improve characteristics of magnetic field spectrum analyzers are discussed. • A new swept-tuned spectrum analyzer of magnetic fields is proposed. • The analyzer uses resonant magnetoelectric effect of magnetic field frequency mixing. • A prototype of the spectrum analyzer is fabricated and characterized.

WITHDRAWN: The Influence of tea pigment on the properties of hydroxypropylmethylcellulose for curing artificial tears (AT) of animal eye

This work aims to study the Influences of tea pigment on the properties of Hydroxypropylmethelcellelose HPMC. Two solutions were prepared; one of them involve: dissolved 0.3 of HPMC in 50 ml of double distillation water with constant stirring via a magnetic mixer. The material will clump and then heated to 80° C until it becomes viscous, cooled and leave disparately for 30 min. Different tests were carried out, such as Osmosmality, cured animal, rheology, zeta potential, density, PH and FTIR. Findings demonstrated that the preservative material acts as a cationic surfactant and as a biocide agent and causes Influences, such as decreasing the oscillatory from 287 to 283 Osm/L, from 6.6 to 6.44, increasing the zeta potential from −20 to −31 mV and mobility from −1.8 to −2.1 (m/s)/(V/cm). From the viewpoint of rheology characteristics, benzalkonium chloride addition makes the viscosity–shear rate relation closer to the standard tear behaviour with shear thinning behaviour.

Two Dimensional Mxene (Ti3C2) Decorated By SnO2 Nanocrystals for Enhanced Chemical Gas Sensors at Room Temperature

IntroductionA low-cost chemical sensor for ammonia (NH3) detection is highly demanded nowadays for several important applications. Two-dimensional (2D) nanomaterials such as graphene/reduced graphene oxide (rGO), transitional metal dicharcogenides, black phosphor and transition metal carbonitride (MXene) have found a promising application in the fields of gas sensing electronics at room temperature due to their unique microstructure, electrical properties and excellent gas adsorptions ability. Decoration of the secondary phase such as noble metals and metal oxide nanocrystals to form heterojunctions with two-dimensional materials can effectively improve the inadequacy of two-dimensional materials based gas sensors. It takes advantages of the difference in the Fermi level of each phase to make the electrons transfer from one material to the other and thus enriching the electron concentration on the surface of one material that is dominant in the electrical transport. In this way, more ionized oxygen is chemisorbed, leading to the improvement of the gas sensing properties [1].In this work, 2D MXene heterojunctions incorporated with SnO2 nanoparticles have been synthesized by using hydrothermal method. The as-fabricated MXene/SnO2 heterojunction based chemiresistive-type sensor showed excellent sensitivity to different concentrations of ammonia from 0.5-100 ppm at room temperature. The response has about 20 times higher than those reported in literature to 100 ppm NH3 and an excellent selectivity.Preparation and characterizations The Ti3AlC2 was purchased directly from Beijing Forsman Corp. The concentrated hydrochloric acid (HCl) was diluted to 9 M. 2 g of lithium fluoride (LiF) was added into 20 ml diluted hydrochloric acid and stirred with magnetic mixer. 2 g Ti3AlC2 was slowly and evenly dispersed in the solution over a period of several minutes and subsequently stirred at 35 ℃ for 48 h to obtain the MXene. 70 mg of MXene powder was dispersed in 30 ml of deionized water after grinding and sonicated for 30 min. 73.5 mg of stannic chloride pentahydrate (SnCl4·5H2O) was added into the suspension and stirred with magnetic stirrer at room temperature. The suspension was then loaded in a 50 ml Teflon-lined autoclave. The autoclave was sealed and heated in an KSL-1200X hydrothermal system at 180 ℃ for 12 h to obtain the MXene-SnO2 hybirds. The samples were then characterized by XRD, SEM, XPS, Raman and TEM-ED. The MXene/SnO2 based chemirestive-type sensor was measured by a static volumetric method. The resistance of the sensor is directly measured by a digital multimeter (Agilent 34410A). The responses of the sensors were defined as the relative change in the resistances of the sensors in the air and those in the tested gas. Results and Conclusions Fig.1a shows the XRD of the prepared samples. Appearance and down-shift of the peak at ~10 oC indicates the successful achievements of MXene and thus the MXene-SnO2 composite heterojunctions [2-3].Fig.1 (b-c) show the micrographs of the surface morphology of the MXene and heterojunctions. The etched MXene material has obvious layered structure with sizes ranging from 2 μm to 4 μm. The thickness of MXene is about 75 nm indicating the sample contains about 100 single layers of MXene. The granular SnO2 nanoparticles are intimately attached to the surface of MXene. Fig.2 (b) shows the Raman spectra of MXene and Mxene/SnO2 heterojunction. The appearance of both D-band and G-band in the MXene/SnO2 heterojunction sample indicated that MXene remained well during the hydrothermal reaction. Fig.2(c) shows the Ti core level (2p) spectra of the MXene and MXene/SnO2. Ti - X corresponds to titanium carbide or titanium oxynitride. Fig.2d indicates that the peaks at 530.1 and 532 eV correspond to oxygen vacancies and O=C-OH, respectively, suggesting that these and surface-adsorbed oxygen tend to form more active sites, thereby enhancing sensing capability.The sensors using MXene/SnO2 heterojuction shows excellent response and selectivity to low-level NH3 from 0.5-9 ppm at RT (Fig.3). Since the work function of MXene (3.4 eV) was slightly lower than that of SnO2 (4.7 eV), Schottky-type junctions were formed across MXene/SnO2 interfaces (Fig.4). Electrons would transfer from SnO2 to MXene, and the depletion layer was deepened on the surface of MXene. MXene could then chemically adsorb more oxygen, and the response of the MXene/SnO2 heterojunction was thus significantly enhanced.

Construction and performance evaluation of a CSC-1 type horizontal rotating micro-bomb combustion-solution isoperibol multifunctional calorimeter

In this work, a CSC-1 type horizontal rotating micro-bomb combustion-solution isoperibol multifunctional calorimeter was constructed. There are three main differences between the structure of this calorimeter and the existing calorimeters: (1) two functions, i.e. the measurements of combustion heat and solution heat were integrated together; (2) Dewar bottle was used as a shared calorimetric container for the determination of combustion heat and solution heat; (3) submersible magnetic mixer replaced the traditional mechanical rod mixer. The energy equivalent of combustion system in the calorimeter was calibrated with NIST SRM 39j benzoic acid, giving the result of (1181.94 ± 0.23) J⋅K−1. Furthermore, the standard specific energy of combustion of salicylic acid was measured using the combustion system, and the result showed that the standard specific energy of combustion of salicylic acid was – (21884.9 ± 5.4) J·g−1 at 298.15 K. Then, the standard molar enthalpy of formation of salicylic acid was calculated to be ΔfHmo[C7H6O3(s),298.15K]=-(589.27±2.98)kJ⋅mol−1. In addition, the energy equivalent of solution system in the calorimeter was calibrated with electrical energy, giving the result of (5.28084 ± 0.00261) J·mV−1. And the standard specific enthalpy of solution of KCl was measured by the solution system in water at 298.15 K, the results indicated that the standard specific and molar enthalpy of solution of KCl (1100 H2O, 298.15 K) were (235.33 ± 0.03) J·g−l and (17543.2 ± 8.9) J·mol−l, respectively. All these results demonstrated that the calorimetric systems of combustion and solution in the developed calorimeter are reliable and feasible.

Enhancement the ability to pump crude oil using rubber solutions

In this research, synthetic rubber (polystyrene-butadiene) and natural rubber (polyisoprene) were dissolved in a common solvent (Toluene) to prepare polymeric solutions by using magnetic mixer at temperatures of 35-45°C. It was observed that the degree of solubility for natural rubber was greater than that one for synthetic rubber. There is an increase in the viscosity and torque for both rubbers along with increasing the synthetic and natural rubbers concentration. Laminar behavior is observed for both polymers since Reynolds number is less than 2300. Natural rubber is more suitable to use in pipes with crude oil

Numerical and experimental investigation of high concentration aqueous alumina nanofluids in a two and three channel heat exchanger

Abstract Nanofluids are often able to provide a method to increase the possible heat transfer of a system, with relatively few detrimental factors created by its inclusion. The use of nanofluids and their optimal concentrations has become an area of great interest as of late, with different nanofluid concentrations being key to a systems success or hindrance. The aim of this work is to examine the impact of nanofluid concentration on the possible heat transfer for different heat sink types containing porous media. In this work, both a numerical and experimental investigation into the impact of an aluminum oxide nanofluid on a fluid flow-based system comprised of porous open-cell aluminum foam to examine their impact on the thermal performance of the system was conducted. The porous media implemented in the experimental work was made of a 6061-T6 aluminum with a porosity of 0.91 and a permeability of 2.3869 × 10−7 m2. The experimental work was carried out for a large range of applied heat flux values varying from 3.8328 W cm-2 to 10.3737 W cm−2. The nanofluid examined was also subjected to varying flow rates. The nanofluid concentration was varied from 1% vol and 2% vol Al2O3–water mixture. The nanofluid was suspended in distilled water and mixed using a magnetic mixer. The performance of the work was examined through the Nusselt number to determine the possible thermal enhancement presented by the nanofluid. The use of high concentration (1% vol) nanofluid paired with the use of two different channel designs, both containing porous media resulted in an average thermal enhancement 15% and a maximum enhancement of 24.5% when compared to that of the 2% vol alumina nanofluid.

Використання мікропіни, виготовленої за допомогою магнітного змішувача, в лікуванні ретикулярного варикозу та телеангіектазій

SummaryThe method of choice for the treatment of reticular varicose veins andteleangiectasias (TAE) is microsclerotherapy using finely dispersed foam. To improvethe result of sclerotherapy, a special device (magnetic mixer) was proposed to improvethe quality of the working foam.The aim of this work is to analyze the results of sclerotherapy of reticular veins andTAE using micro-foam obtained by magnetic mixer.Materials and methods. The analysis of the use of microsclerotherapy in the Clinicof vascular surgery of the Main Military Clinical Hospital was carried out. The studyinvolved 100 patients aged 18 to 84 years, who underwent sessions of reticular vein andTAE sclerotherapy. There were 81 women and 18 men. The patients were allocated totwo groups.In group 1 (n = 49), sclerotherapy was carried out using a standard technique.Polidocanol 600 (Sclerovein) was introduced in the form of micro-dispersed foam madeby the Tessari method.In group 2 (n = 51), scleroobliteration was performed using foam made with a«Cimaron» magnetic mixer (produced in Ukraine).Control examinations and evaluation of the results were followed up for 7 days, 1month, and 6 months after the procedure on the basis of a clinical examination.Results and discussion. All patients achieved a positive result in the form ofelimination of reticular veins and TAE, however, at follow-up examination after 7 daysand 1 month, the following complications were observed: subcutaneous hematomas in34 (69.4%) patients of group 1 and in 35 (68, 6%) of patients of the 2nd group, phlebitisof tributaries - in 4 (8.1%) patients of the 1st group and 2 (5.8%) patients of the 2ndgroup. These complications did not require the appointment of additional medications.During the follow-up examination after 1 month, hyperpigmentation was observedin 16 (32.6%) patients of the 1st group and 14 (27.5%) patients of the 2nd group, metingafter 1 month - in 6 (12.2%) patients of the 1st group and 4 (7%) patients of the 2ndgroup.A good (excellent and good) aesthetic result, which completely satisfies patients,was achieved in 79 (79%) cases. In other cases, an improvement in appearance and adecrease in disease symptoms were noted.The cosmetic result after surgery was assessed by patients of the first group asfollows: excellent - 18 (36.7%) patients of the 1st group and 22 (43.1%) patients of the2nd group, good - 19 (38.8%) patients 1 group 2 and 20 (39.2%) patients of group 2,satisfactory - 11 (22.4%) patients of group 1 and 9 (17.6%) patients of group 2, therewere no unsatisfactory results.Conclusions. Sclerotherapy of reticular veins and telangiectasias using foam madeby magnetic mixer and a decrease in the concentration of sclerosant made it possible toachieve a positive result in group 2 (excellent and good results prevailed: 37 (75.5%)patients in group 1 and 42 (86.3 %) of patients of the 2nd group (p <0.05)).

Two Dimensional Mxene (Ti3C2) Decorated By SnO2 Nanocrystals for Enhanced Chemical Gas Sensors at Room Temperature

Introduction A low-cost chemical sensor for ammonia (NH3) detection is highly demanded nowadays for several important applications. Two-dimensional (2D) nanomaterials such as graphene/reduced graphene oxide (rGO), transitional metal dicharcogenides, black phosphor and transition metal carbonitride (MXene) have found a promising application in the fields of gas sensing electronics at room temperature due to their unique microstructure, electrical properties and excellent gas adsorptions ability. Decoration of the secondary phase such as noble metals and metal oxide nanocrystals to form heterojunctions with two-dimensional materials can effectively improve the inadequacy of two-dimensional materials based gas sensors. It takes advantages of the difference in the Fermi level of each phase to make the electrons transfer from one material to the other and thus enriching the electron concentration on the surface of one material that is dominant in the electrical transport. In this way, more ionized oxygen is chemisorbed, leading to the improvement of the gas sensing properties [1].In this work, 2D MXene heterojunctions incorporated with SnO2 nanoparticles have been synthesized by using hydrothermal method. The as-fabricated MXene/SnO2 heterojunction based chemiresistive-type sensor showed excellent sensitivity to different concentrations of ammonia from 0.5-100 ppm at room temperature. The response has about 20 times higher than those reported in literature to 100 ppm NH3 and an excellent selectivity. Preparation and characterizations The Ti3AlC2 was purchased directly from Beijing Forsman Corp. The concentrated hydrochloric acid (HCl) was diluted to 9M. 2g of lithium fluoride (LiF) was added into 20ml diluted hydrochloric acid and stirred with magnetic mixer. 2g Ti3AlC2 was slowly and evenly dispersed in the solution over a period of several minutes and subsequently stirred at 35℃ for 48h to obtain the MXene. 70 mg of MXene powder was dispersed in 30ml of deionized water after grinding and sonicated for 30min. 73.5mg of stannic chloride pentahydrate (SnCl4·5H2O) was added into the suspension and stirred with magnetic stirrer at room temperature. The suspension was then loaded in a 50ml Teflon-lined autoclave. The autoclave was sealed and heated in an KSL-1200X hydrothermal system at 180℃ for 12h to obtain the MXene-SnO2 hybirds. The samples were then characterized by XRD, SEM, XPS, Raman and TEM-ED. The MXene/SnO2 based chemirestive-type sensor was measured by a static volumetric method. The resistance of the sensor is directly measured by a digital multimeter (Agilent 34410A). The responses of the sensors were defined as the relative change in the resistances of the sensors in the air and those in the tested gas. Results and Conclusions Fig.1a shows the XRD of the prepared samples. Appearance and down-shift of the peak at ~10 oC indicates the successful achievements of MXene and thus the MXene-SnO2 composite heterojunctions [2-3].Fig.1 (b-c) show the micrographs of the surface morphology of the MXene and heterojunctions. The etched MXene material has obvious layered structure with sizes ranging from 2 μm to 4 μm. The thickness of MXene is about 75 nm indicating the sample contains about 100 single layers of MXene. The granular SnO2 nanoparticles are intimately attached to the surface of MXene. Fig.2 (b) shows the Raman spectra of MXene and Mxene/SnO2 heterojunction. The appearance of both D-band and G-band in the MXene/SnO2 heterojunction sample indicated that MXene remained well during the hydrothermal reaction. Fig.2(c) shows the Ti core level (2p) spectra of the MXene and MXene/SnO2. Ti - X corresponds to titanium carbide or titanium oxynitride. Fig.2d indicates that the peaks at 530.1 and 532 eV correspond to oxygen vacancies and O=C-OH, respectively, suggesting that these and surface-adsorbed oxygen tend to form more active sites, thereby enhancing sensing capability.The sensors using MXene/SnO2 heterojuction shows excellent response and selectivity to low-level NH3 from 0.5-9 ppm at RT (Fig.3). Since the work function of MXene (4.465 eV) was slightly lower than that of SnO2 (4.7 eV), Schottky-type junctions were formed across MXene/SnO2 interfaces (Fig.4). Electrons would transfer from SnO2 to MXene, and the depletion layer was deepened on the surface of MXene. MXene could then chemically adsorb more oxygen, and the response of the MXene/SnO2 heterojunction was thus significantly enhanced.

Effective Metal Mixing at a Low Melt Level in a Furnace or Mixer

The problem of increasing the efficiency of melt mixing in a furnace bath or mixer at low melt levels using an electromagnetic mixer installed on the furnace or mixer side is considered. It is proposed to use a transverse magnetic flux mixer as an electromagnetic mixer. A comparative analysis of devices with a longitudinal and transverse running magnetic field is performed. To perform the comparative analysis, mathematical modeling is carried out using the ANSYS software. By means of parametric mathematical models of electromagnetic mixers with a longitudinal and transverse magnetic field installed on the mixer side, it is possible to accurately reflect electromagnetic processes and obtain dependences of electromagnetic forces in the melt, to determine the release of thermal power in the melt and inductor, and power consumption and cosφ for different linear current load and different melt levels in the mixer. Based on the results of mathematical modeling, two types of electromagnetic mixers are compared and best practice advices are provided for choosing the mixer type depending on the initial metallurgical process conditions.

Energy efficient electrocoagulation using baffle-plates electrodes for efficient Escherichia coli removal from wastewater

A new electrocoagulation reactor (EC), which utilises the concepts of baffle-plates, has been applied to remove Escherichia coli (E. coli) from wastewater. This new aluminium-based EC reactor utilises perforated baffle-plates electrodes to mix water, which reduces the need for mechanical or magnetic mixers that require extra power to work. This new reactor has been used to treat E. coli containing wastewater samples, considering the effects of different parameters such as treatment time (TT), inter-electrode distance (IED), and current density (CD). A statistical analysis has also been commenced to evaluate the influence of each parameter on the removal of E. coli. Additionally, an economic study has been conducted to assess the operating cost of the new reactor. The outcomes of the experimental work confirmed that the new reactor removes as high as 96 % of the E. coli within 20 min of electrolysis at IED of 0.5 cm, and CD of 1.5 mA/cm2. Additionally, it has been found that the operating cost of the new reactor is 0.11 US $/m3 (for E. coli removal), which is less than operating cost of traditional reactors. Finally, it has been found that the effect of the studied parameters on E. coli removal followed the order: TT>CD>IED.

The application of novel magnetically coupled mixer drives in bioreactors of up to 15 m3

We introduce a novel magnetically coupled mixer drive for biotechnological, pharmaceutical and chemical applications requiring high-grade aseptic conditions. The proposed design enables its application in larger volume bioreactors compared to traditional magnetic drives, due to a possibility of introducing higher power quantities per individual rotor, while ensuring higher mixing intensity.In the following study, we provide information on the design aspects of the novel magnetic drive and demonstrate the principles behind both theoretical and experimental maximal torque and other key working parameter evaluation. Based on the mentioned principles, magnetic mixer drives were developed for laboratory (5 dm3) and pilot-scale (15 m3) bioreactors. The specific power inputs relative to the agitation rates for the mentioned mixers were experimentally determined in water for two impeller types: six-bladed Rushton and three-bladed Pitched-blade turbines. The performance of the novel magnetic drive was evaluated during Kluyveromyces marxianus cultivations utilizing whey (a well known byproduct of the dairy industry) as the main substrate source in the 15 m3 bioreactor.The obtained results show that the novel magnetic drive can be successfully applied in 15 m3 bioreactors, while providing sufficient mixing of the cultivation broth for biomass growth.

Synthesis of pure Zinc Oxid (Semiconductor) and ZnO:Ga Nanostructure for Different Sensing Applications

The research involved the preparation of ZnO and ZnO:Ga by a simple chemical process and inexpensive materials, namly a hydrothermal method by adding 0.05M of zinc nitrate and 0.05M of hexamethylenetetramine (C6H12N4) to the cell manufactured for this purpose. The cell is in a laboratory oven for eight hours at a constant temperature up to 150 oC. For preparing of zinc oxide impregnated with Ga, 4% gallium nitride Ga (NO3)3.xH2O is added to the previous prepared solution under continuous stirring effect using a magnetic mixer. Several effects have been studied in the development of this hydrothermal method, which are precipitated on the zinc oxide layer as a pre-prepared seed layer by fast thermal oxidation of zinc metal 250 nm to achieve optimal conditions leading to the best results for applications. The work also included a study and analysis of the optical and synthetic properties of the prepared zinc oxide nanostructure. These prepared membranes have been used in the best conditions as a multi-application sensors: gas sensors where the ZnO:Ga deposited on the basis of quartz coated with antimony tin oxide as a gas sensor for very dangerous hydrogen gas. The effect of different concentration of gas on resistance of ZnO:Ga over time has been studied. We also studied and manufactured sensors that work as solar cells with high efficiency using Iraqi materials equipped with Al-Mansour State Company and simple conventional devices available in the local market. In this paper, a mechanical sensor is designed to monitor the salt content and improve the water quality. Receptors (where the cell is placed between two ends: the first end represents a piezo segment and the second end represents the ZnO:Ga precipitated on the 134 bases of quartz coated with antimony tin oxide). The range of operating frequencies used in this research ranges from 1500-20000 KHz. Tests in this research included recording the resonant frequency at the first rank of all prepared samples and calculating the damping factor as a function of time.

Metal Oxide (Quantum Dots) for Gas Sensor Application

The research included the preparation of zinc oxide (Quantum Dots) with a diameter of 4.33- 6.37 nm as indicated in the results of transmissionelectron (HRTEM) microscopy at different points of the colloidal (ZnO Q.Ds) produced using Iraqi materials and simple conventional devices available in the local market. . The manufacturing process was carried out by a simple chemical process by adding 0.4 g of crystallized zinc acetate to 100 ml of isopropyl alcohol C3H 9O with constant stirring for a period of 30 minutes under the influence of 70 oC temperature. The effect of adding sodium sulphide (Na2S) has been studied where the weight (0.15 grams) was added to the previous solution prepared within the above paragraph and then added 10 ml of TEA under the effect of constant stirring using a magnetic mixer for five hours . Then a white colloidal ZnO was obtained and separated using a 6000 rpm centrifuge for only one hour. The product was washed with distilled water and methanol and dried in a vacuum oven for 7 hours at a drying temperature of 50 oC. The results of the synthesis properties of zinc oxidized colloidal quantum dots by X-ray diffraction study showed that zinc oxide granules were centered towards (102), (110), (103), (200), (112), (201), (101), (100) and (002). The sensitivity results showed high efficiency of gas sensing under lighting effect.