Search results for: controller synthesis

Authors: Wallia Majeed

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Humidity sensors based on doped ZnO-rGO composites have shown promise due to their sensitivity to humidity changes. Here, it report on the hydrothermal synthesis of ZnO-rGO and doped ZnO-rGO nanocomposites, incorporating cobalt and iron dopants at 2% concentration. X-ray diffraction confirmed successful doping, while scanning electron microscopy revealed the composite's layered structure with embedded ZnO rods. To evaluate their performance, humidity sensors were fabricated by depositing aluminum electrodes on silicon substrates coated with the composites. The Fe-doped ZnO-rGO sensor exhibited rapid response (27 s) and recovery times (24 s) across a wide humidity range (11% to 97% RH), surpassing ZnO-rGO and Co-doped ZnO-rGO variants in sensitivity (2.2k at 100 Hz). These findings highlight Fe-doped ZnO-rGO composites as ideal candidates for humidity sensing applications, offering enhanced performance crucial for environmental monitoring and industrial processes.

Keywords: humidity sensors, nanocomposites, hydrothermal synthesis, sensitivity

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Authors: Ch. Sandeep Kumar Subudhi, S. Sivanandam

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Our system is to monitor the human body temperature, blood pressure (BP), Pulse Rate and ECG and tracking the patient location. In our system the body temperature is detected by using LM35 temperature sensor, blood pressure is detected by the BP sensor, pulse rate is detected by the ear plug pulse sensor and the ECG is detected by the three lead ECG sensor in the working environment of the patient. The sensed information is sent to the PIC16F877 microcontroller through signal conditioning circuit. A desired amount of sensor value is set and if it is exceeded preliminary steps should be taken by indication by buzzer. The sensor information will be transmitted from the patient unit to the main controller unit with the help of Zigbee communication medium which is connected with the microcontrollers in the both units. The main controller unit will send those sensor data as well as the location of that patient by the help of GPS module to the observer/doctor. The observer/doctor can receive the SMS sent by GSM module and further decision can be taken. The message is sent to a cell phone using global system mobile (GSM) Modem. MAX232 acts as a driver between microcontroller and modem.

Keywords: LM35, heart beat sensor, ECG Sensor, BP Sensor, Zigbee module, GSM module, GPS module, PIC16F877A microcontroller

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Authors: Amgad Rezk, Heba Ahmed, Leslie Yeo

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Ultrasound presents a powerful means for material synthesis. In this talk, we showcase a new field demonstrating the possibility for harnessing sound energy sources at considerably higher frequencies (10 MHz to 1 GHz) compared to conventional ultrasound (kHz and up to ~2 MHz) for crystalising and manipulating a variety of nanoscale materials. At these frequencies, cavitation—which underpins most sonochemical processes—is largely absent, suggesting that altogether fundamentally different mechanisms are at dominant. Examples include the crystallization of highly oriented structures, quasi-2D metal-organic frameworks and nanocomposites. These fascinating examples reveal how the highly nonlinear electromechanical coupling associated with high-frequency surface vibration gives rise to molecular ordering and assembly on the nano and microscale.

Keywords: high-frequency acoustics, microfluidics, crystallisation, composite nanomaterials

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Authors: Pesaru Vigneshwar Reddy, Parvathaneni Pavan

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Green organic chemistry which is the latest and one of the most researched topics now-a- days has been in demand since 1990’s. Majority of the research in green organic chemistry chemicals are some of the important starting materials for greater number of major chemical industries. The production of organic chemicals has raw materials (or) reagents for other application is major sector of manufacturing polymers, pharmaceuticals, pesticides, paints, artificial fibers, food additives etc. organic synthesis on a large scale compound to the labratory scale, involves the use of energy, basic chemical ingredients from the petro chemical sectors, catalyst and after the end of the reaction, seperation, purification, storage, packing distribution etc. During these processes there are many problems of health and safety for workers in addition to the environmental problems caused there by use and deposition as waste. Green chemistry with its 12 principles would like to see changes in conventional way that were used for decades to make synthetic organic chemical and the use of less toxic starting materials. Green chemistry would like to increase the efficiency of synthetic methods, to use less toxic solvents, reduce the stage of synthetic routes and minimize waste as far as practically possible. In this way, organic synthesis will be part of the effort for sustainable development Green chemistry is also interested for research and alternatives innovations on many practical aspects of organic synthesis in the university and research labaratory of institutions. By changing the methodologies of organic synthesis, health and safety will be advanced in the small scale laboratory level but also will be extended to the industrial large scale production a process through new techniques. The three key developments in green chemistry include the use of super critical carbondioxide as green solvent, aqueous hydrogen peroxide as an oxidising agent and use of hydrogen in asymmetric synthesis. It also focuses on replacing traditional methods of heating with that of modern methods of heating like microwaves traditions, so that carbon foot print should reduces as far as possible. Another beneficiary of this green chemistry is that it will reduce environmental pollution through the use of less toxic reagents, minimizing of waste and more bio-degradable biproducts. In this present paper some of the basic principles, approaches, and early achievements of green chemistry has a branch of chemistry that studies the laws of passing of chemical reactions is also considered, with the summarization of green chemistry principles. A discussion about E-factor, old and new synthesis of ibuprofen, microwave techniques, and some of the recent advancements also considered.

Keywords: energy, e-factor, carbon foot print, micro-wave, sono-chemistry, advancement

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Authors: Tareg M. Elsunaki, Suleiman A. Arafa, Mohamed A. Abd-Alla

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New interesting thermal stable polyesters containing 1-methyl-4-piperidone moiety in the main chain have been synthesized. These polyesters were synthesized by interfacial polycondensation technique of 3,5-bis(4-hydroxybenzylidene)-1-methyl-4-piperidone (I) and 3,5-bis(4-hydroxy-3-methoxy benzyli-dene)-1-methyl-4-piperidone (II) with terphthaloyl, isophthaloyl, 4,4'-diphenic, adipoyl and sebacoyl dichlorides. The yield and the values of the reduced viscosity of the produced polyesters were found to be affected by the type of an organic phase. In order to characterize these polymers, the necessary model compounds (A), (B) were prepared from (I), (II) respectively and benzoyl chloride. The structure of monomers (I), (II), model compounds and resulting polyesters were confirmed by IR, elemental analysis and 1HNMR spectroscopy. The various characteristic of the resulting polymers including solubility, thermal properties, viscosity and X-ray analysis were also studied.

Keywords: synthesis, characterization, new polyesters, chemistry

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Authors: Jong-Ho Moon, Dong-Ho Lee, Hyunuk Kim, Young Cheol Park, Jong-Seop Lee, Jae-deok Jeon, Hyung-Keun Lee

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A novel membrane reactor process for DMC synthesis from carbon dioxide has been developing in Korea Institute of Energy Research. The scheme of direct synthesis of DMC from CO₂ and Methanol is 'CO₂ + 2MeOH ↔ DMC + H₂O'. Among them, reactants are CO₂ and MeOH, product is DMC, and byproduct is H₂O (water). According to Le Chatelier’s principle, removing byproduct (water) can shift the reaction equilibrium to the right (DMC production). The main purpose of this process is removing water during the reaction. For efficient in situ water removal (dehydration) and DMC separation, zeolite 4A membranes with very small pore diameter and hydrophilicity were introduced. In this study, pervaporation performances of binary and ternary DMC / methanol / water mixtures were evaluated.

Keywords: dimehtyl carbonate, methanol, water, zeolite membrane, pervaporation

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Authors: Hassina Harkat, Samiha Taybe, Salima Loucif, Valérie Beneteau, Patrick Pale

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Indole and its derivatives have attracted great interest because of their importance in the synthetic organic and medicinal chemistry. They are widely used as anti hypertension, anti tubercular, anticancer activity, antiviral, Alzheimer's disease, antioxidant properties, and free radical induced lipid peroxidation. Many drugs and natural products contain indole moiety, such as the vinca alkaloids, fungal metabolites and marine natural products. Generally applicable synthetic methods for indole moiety involve ring closure to form the pyrrole. Indole derivatives can also be accessed by further functionalization of the indole nucleus. Therefore we report a mild and efficient protocol for the synthesis of analogues of indole catalyzed via zeolithe USY doped with CuI under solvent-free conditions.

Keywords: indole, zeolithe, USY-CuI, heterogeneous catalysis

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Authors: Piya Roychoudhury, Ruma Pal

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Cyanobacteria, commonly known as blue green algae were found to be an effective bioreagent for nanoparticle synthesis. Nowadays silver nanoparticles (AgNPs) are very popular due to their antimicrobial and anti-proliferative activity. To exploit these characters in different biotechnological fields, it is very essential to synthesize more stable, non-toxic nano-silver. For this reason silver-gold alloy (Ag-AuNPs) nanoparticles are of great interest as they are more stable, harder and more effective than single metal nanoparticles. In the present communication we described a simple technique for rapid synthesis of biocompatible AgNP and Ag-AuNP employing cyanobacteria, Leptolyngbya and Lyngbya respectively. For synthesis of AgNP the biomass of Leptolyngbya valderiana (200 mg Fresh weight) was exposed to 9 mM AgNO3 solution (pH 4). For synthesis of Ag-AuNP Lyngbya majuscula (200 mg Fresh weight) was exposed to equimolar solution of hydrogen tetra-auro chlorate and silver nitrate (1mM, pH 4). After 72 hrs of exposure thallus of Leptolyngyba turned brown in color and filaments of Lyngbya turned pink in color that indicated synthesis of nanoparticles. The produced particles were extracted from the cyanobacterial biomass using nano-capping agent, sodium citrate. Firstly, extracted brown and pink suspensions were taken for Energy Dispersive X-ray (EDAX) analysis to confirm the presence of silver in brown suspension and presence of both gold and silver in pink suspension. Extracted nanoparticles showed a distinct single plasmon band (AgNP at 411 nm; Ag-Au NP at 481 nm) in Uv-vis spectroscopy. It was revealed from Transmission electron microscopy (TEM) that all the synthesized particles were spherical in nature with a size range of ~2-25 nm. In X-ray powder diffraction (XRD) analysis four intense peaks appeared at 38.2°, 44.5°, 64.8°and 77.8° which confirmed the crystallographic nature of synthesized particles. Presence of different functional groups viz. N-H, C=C, C–O, C=O on the surface of nanoparticles were recorded by Fourier transform infrared spectroscopy (FTIR). Scanning Electron microscopy (SEM) images showed the surface topography of metal treated filaments of cyanobacteria. The stability of the particles was observed by Zeta potential study. Antibiotic property of synthesized particles was tested by Agar well diffusion method against gram negative bacteria Pseudomonas aeruginosa. Overall, this green-technique requires low energy, less manufacturing cost and produces rapidly eco-friendly metal nanoparticles.

Keywords: cyanobacteria, silver nanoparticles, silver-gold alloy nanoparticles, spectroscopy

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Authors: Kouzi Katia

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This paper proposes a Direct Torque Control (DTC) algorithm of dual Stator Induction Motor (DSIM) drive using two approach intelligent techniques: Artificial Neural Network (ANN) approach replaces the switching table selector block of conventional DTC and Mamdani Fuzzy Logic controller (FLC) is used for stator resistance estimation. The fuzzy estimation method is based on an online stator resistance correction through the variations of stator current estimation error and its variation. The fuzzy logic controller gives the future stator resistance increment at the output. The main advantage of suggested algorithm control is to reduce the hardware complexity of conventional selectors, to avoid the drive instability that may occur in certain situation and ensure the tracking of the actual of the stator resistance. The effectiveness of the technique and the improvement of the whole system performance are proved by results.

Keywords: artificial neural network, direct torque control, dual stator induction motor, fuzzy logic estimator, switching table

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Authors: Hamad Almohamadi, Nabeel H. Alharthi, Abdulrahman Aljabri

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In this study, two-dimensional CuFeOx is deposited on nickel foam for the fabrication of electrocatalyst for oxygen evolution reaction (OER). The in-situ hydrothermal synthesis of CuFeOx in presence of aloe vera extract was found to yield unique nano-rose-like morphology which aided to improve the electrochemical surface area of the electrode. The phytochemical assisted synthesis of CuFeOx using 75% aloe vera extract resulted in improved OER electrocatalytic performance by attaining the overpotential of 310 mV for 50 mA cm−2 and 410 mV for 100 mA cm−2. The electrode also sustained robust stability throughout the 50 h of chronopotentiometry studies under alkaline electrolyte conditions, thus proving to be prospective electrode material for efficient OER in electrochemical water splitting.

Keywords: water splitting, phytochemicals, oxygen evaluation reaction, Tafel's slope, stability

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Authors: Wega Trisunaryanti, Hesty Kusumastuti, Iip Izul Falah, Muhammad Fajar Marsuki, Rahmad Nuryanto

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Synthesis of Ni supported on mesopore silica-alumina (MSA) for hydrocracking of pyrolyzed α-cellulose had been carried out. The silica and alumina were extracted from Sidoarjo mud. Gelatin from catfish bone was used as a template for the mesopore design. The MSA was synthesized by using hydrothermal method at 100 °C for 24 h and calcined at 550 °C for 4 h then characterized by using X-Ray Diffraction Spectrometer (XRD) and Nitrogen Gas Sorption Analyzer (GAS). The Ni metal was loaded to the MSA by wet impregnation method. The catalytic activity in the hydrocracking reaction of pyrolyzed α-cellulose was carried out at 450 °C for 2 h. The MSA synthesized in this work is an amorphous material with specific surface area, total pore volume, and average pore diameter of 212.29 m²/g, 1.29 cm³/g, and 20.05 nm, respectively. The Ni/MSA catalyst produced 73.02 wt.% of liquid product in hydrocracking of pyrolyzed α-cellulose.

Keywords: catalyst, gelatin, hydrocracking, mesopore silica-alumina, α-cellulose

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Authors: S. Sonkham, U. Pinsopon, W. Chatlatanagulchai

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This paper presents a method of sliding mode control (SMC) designing and developing for the servo system in a dual-stage actuator (DSA) hard disk drive. Mathematical modelling of hard disk drive actuators is obtained, extracted from measuring frequency response of the voice-coil motor (VCM) and PZT micro-actuator separately. Matlab software tools are used for mathematical model estimation and also for controller design and simulation. A model-reference approach for tracking requirement is selected as a proposed technique. The simulation results show that performance of a model-reference SMC controller design in DSA servo control can be satisfied in the tracking error, as well as keeping the positioning of the head within the boundary of +/-5% of track width under the presence of internal and external disturbance. The overall results of model-reference SMC design in DSA are met per requirement specifications and significant reduction in %off track is found when compared to the single-state actuator (SSA).

Keywords: hard disk drive, dual-stage actuator, track following, hdd servo control, sliding mode control, model-reference, tracking control

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Authors: Yongkui Cui, Fengping Wang, Hailei Zhao, Muhammad Zubair Iqbal, Ziya Wang, Yan Li, Pengpeng LV

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The novel 3D SnO cabbages self-assembled by nanosheets were successfully synthesized via template-free hydrothermal growth method under facile conditions.The XRD results manifest that the as-prepared SnO is tetragonal phase. The TEM and HRTEM results show that the cabbage nanosheets are polycrystalline structure consisted of considerable single-crystalline nanoparticles. Two typical Raman modes A1g=210 and Eg=112 cm-1 of SnO are observed by Raman spectroscopy. Moreover, galvanostatic cycling tests has been performed using the SnO cabbages as anode material of lithium ion battery and the electrochemical results suggest that the synthesized SnO cabbage structures are a promising anode material for lithium ion batteries.

Keywords: electrochemical property, hydrothermal synthesis, lithium ion battery, stannous oxide

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Authors: Ruswanto Ruswanto, Richa Mardianingrum, Tita Nofianti, Nur Rahayuningsih

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Tuberculosis (TB) is a chronic disease as a result of Mycobacterium tuberculosis. It can affect all age groups, and hence, is a global health problem that causes the death of millions of people every year. One of the drugs used in tuberculosis treatment is isonicotinohydrazide. In this study, N'-benzoylisonicotinohydrazide derivative compounds (a-l) were prepared using acylation reactions between isonicotinohydrazide and benzoyl chloride derivatives, through the reflux method. Molecular docking studies suggested that all of the compounds had better interaction with Mycobacterium tuberculosis enoyl-acyl carrier protein reductase (InhA) than isonicotinohydrazide. It can be concluded that N'-benzoylisonicotinohydrazide derivatives (a-l) could be used as anti-tuberculosis candidates. From the docking results revealed that all of the compounds interact well with InhA, with compound g (N'-(3-nitrobenzoyl)isonicotinohydrazide) exhibiting the best interaction.

Keywords: anti-tuberculosis , docking, InhA, N'-benzoylisonicotinohydrazide, synthesis

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Authors: Tzu-Wen Liu, Yi-Feng Lin, Yu-Shao Chen

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CO_2 is believed to be partly responsible for changes to the global climates. Carbon capture and storage (CCS) is one way to reduce carbon dioxide emissions in the past. Recently, how to convert the captured CO_2 into fine chemicals gets lots of attention owing to reducing carbon dioxide emissions and providing greener feedstock for the chemicals industry. A variety of products can be manufactured from carbon dioxide and the most attractive products are cyclic carbonates. Therefore, the kind of catalyst plays an important role in cycloaddition of carbon dioxide to epoxides. Magnesium oxide can be an efficiency heterogeneous catalyst for the cycloaddition of carbon dioxide to epoxides because magnesium oxide has both acid and base active sites and can provide the adsorption of carbon dioxide, promoting ring-opening reaction. Spinning disk reactor (SDR) is one of the device of high-gravity technique and has successfully used for synthesis of nanoparticles by precipitation methods because of the high mass transfer rate. Synthesis of nanoparticles in SDR has advantages of low energy consumption and easy to scale up. The aim of this research is to synthesize magnesium hydroxide nanoparticles in SDR as precursors for magnesium oxide. Experimental results showed that the calcination temperature of magnesium hydroxide to magnesium oxide, and the pressure and temperature of cycloaddition reaction had significantly effect on the conversion and selectivity of the reaction.

Keywords: magnesium oxide, catalyst, cycloaddition, spinning disk reactor, carbon dioxide

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Authors: Claudia Matassa, Matthias Hohne, Dominic Ormerod, Yamini Satyawali

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Chiral amines integrate the backbone of several active pharmaceutical ingredients (APIs) used in modern medicine for the treatment of a vast range of diseases. Despite the demand, their synthesis remains challenging. Besides a range of chemicals and enzymatical methods, chiral amine synthesis using transaminases (EC 2.6.1.W) represents a useful alternative to access this important class of compounds. Even though transaminases exhibit excellent stereo and regioselectivity and the potential for high yield, the reaction suffers from a number of challenges, including the thermodynamic equilibrium, product inhibition, and low substrate solubility. In this work, we demonstrate a membrane assisted strategy for addressing these challenges. It involves the use of high molecular weight (HMW) amine donors for the transaminase-catalyzed synthesis of 4-phenyl-2-butylamine in both aqueous and organic solvent media. In contrast to common amine donors such as alanine or isopropylamine, these large molecules, provided in excess for thermodynamic equilibrium shifting, are easily retained by commercial nanofiltration membranes; thus a selective permeation of the desired smaller product amine is possible. The enzymatic transamination in aqueous media, combined with selective product removal shifted the equilibrium enhancing substrate conversion by an additional 25% compared to the control reaction. Along with very efficient amine product removal, there was undesirable loss of ketone substrate and low product concentration was achieved. The system was therefore further improved by performing the reaction in organic solvent (n-heptane). Coupling the reaction system with membrane-assisted product removal resulted in a highly concentrated and relatively pure ( > 97%) product solution. Moreover, a product yield of 60% was reached, compared to 15% without product removal.

Keywords: amine donor, chiral amines, in situ product removal, transamination

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Authors: Amina Omer, Ikram Elsiddig

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Arctostaphylos uvaursi is a plant of the family Ericaceae, it’s used in skin care products mostly for its depigmenting action, due to the presence of hydroquinones that are well known inhibitors of tyrosinase, an enzyme involved in melanin biosynthesis in humans. The main hydroquinone found within the A. uvaursi is arbutin, which is found with varying percentage within the plant depending on the season, and area from which the plant is harvested. An in vitro experiment has shown that the arbutin found within the bearberry leaf extract inhibited the biosynthesis of melanin in human melanoma cells and in three-dimensional human skin model. Madurella mycetomatis is filamentous fungus that causes the fungal form of mycetoma known as eumycetoma, with existing anti-fungals and surgery, only 35% of people living eumycetoma are treated, M. mycetomatis has been found to shield itself against the antifungal therapy through the production of melanin decreasing the effectiveness of the therapy, therefore there is a need for a new and more effective therapy. The aim of the study was to investigate and compare the effect of arbutin powder and aqueous extract of A. uvaursi containing arbutin on the biosynthesis of melanin by M. mycetomatis. The experiment was carried out by culturing M. mycetomatis on minimal media composed of 2% agar, 15 mM glucose, 10 mM MgSO4, 29.4 mM KH2PO4, 13 mM glycin and 80mg/l gentamicin, the media was supplied with different concentration of arbutin solution (5, 25 50,and 75mg) and aqueous extract of A. uvaursi to contain arbutin with concentrations (5, 25 50,and 75mg), the plates were incubated for two month and the result was observed by the naked eye. The results revealed that the arbutin powder had an inhibitory effect on melanin synthesis by M. mycetomatis that correlated with its established inhibitory effect on melanin synthesis in humans. The inhibitory effect of arbutin on melanin synthesis by M. mycetomatis was found to be dose dependent. A. uvaursi aqueous leaf extract containing arbutin was also found to decrease melanin production by M. mycetomatis, however plates containing high concentrations of aqueous extract couldn’t be assessed for its melanin inhibitory effect due to the high content of carbohydrates in the extract that promoted the growth of fungi Asperigullus niger rendering the plates unsuitable for visual inspection. In conclusion inhibition of melanin synthesis was observed on the arbutin powder as well as the aqueous extract containing arbutin. A. uvaursi is known to exhibit anti-inflammatory activity, which can aid in wound healing that is beneficial in the chronic inflammation caused by M. mycetomatis.

Keywords: arbutin, arctostaphylos, Madurella, melanin

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Authors: Nyiko M. Chauke, James Ramontja, Richard M. Moutloali

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The zeolite ZSM-22 material demonstrated effective hydrophilic character as a nanoadditive filler in the preparation of nanocomposite membranes. In this study, nanorods ZSM-22 zeolite materials were hydrothermally synthesised from a homogenous gel mixture prepared using different silica precursors: colloidal silica, fumed silica, tetraethylorthosilicate (TEOS), and aluminium precursor: aluminium sulphate octadecahydrate (Al₂(SO₄)₃.18H₂O to Si/Al of 60. This was focused on developing a defect-free zeolite framework for effective use in applications such as membrane separation process, adsorption, and catalysis. The obtained ZSM-22 zeolite materials with 60 Si/Al ratio exhibits high crystallinity, hydrophilicity, and needle-like morphologies, suggesting successful synthesis as shown by X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Fourier-Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) physicochemical analysis. It was revealed that the use of different nature of silica precursors significantly influenced the properties of the final product and contributed to the development of defect-free zeolite material. As such, the crystalline nanorods of Theta-1 (TON) ZSM-22 obtained from TEOS silica showed high phase purity, defect-free, and narrow particle size distribution. Morphological analysis exhibited that the use of TEOS as silica precursor was effective than its counterparts and produced high crystalline need-like agglomerated particles.

Keywords: silica precursor, hydrothermal synthesis, zeolite material, ZSM-22

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Authors: Otilia Ruxandra Vasile, Ecaterina Andronescu, Cristina Daniela Ghitulica, Bogdan Stefan Vasile, Roxana Trusca, Eugeniu Vasile, Alina Maria Holban, Carmen Mariana Chifiriuc, Florin Iordache, Horia Maniu

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Engineered powders offer great promise in several applications, but little information is known about cytotoxicity effects. The aim of the current study was the synthesis and cytotoxicity examination of silver powders using pyrosol method at temperatures of 600°C, 650°C and 700°C, respectively sol-gel method and calcinations at 500°C, 600°C, 700°C and 800°C. We have chosen to synthesize and examine silver particles cytotoxicity due to its use in biological applications. The synthesized Ag powders were characterized from the structural, compositional and morphological point of view by using XRD, SEM, and TEM with SAED. In order to determine the influence of the synthesis route on Ag particles cytotoxicity, different sizes of micro and nanosilver synthesized powders were evaluated for their potential toxicity. For the study of their cytotoxicity, cell cycle and apoptosis have been done analysis through flow cytometry on human colon carcinoma cells and mesenchymal stem cells and through the MTT assay, while the viability and the morphological changes of the cells have been evaluated by using cloning studies. The results showed that the synthesized silver nanoparticles have displayed significant cytotoxicity effects on cell cultures. Our synthesized silver powders were found to present toxicity in a synthesis route and time-dependent manners for pyrosol synthesized nanoparticles; whereas a lower cytotoxicity has been measured after cells were treated with silver nanoparticles synthesized through sol-gel method.

Keywords: Ag, cytotoxicity, pyrosol method, sol-gel method

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Authors: Nithin Krisshna Gunasekaran, Prathima Prabhu Tumkur, Nicole Nazario Bayon, Krishnan Prabhakaran, Joseph C. Hall, Govindarajan T. Ramesh

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Cerium oxide and turmeric have antioxidant properties, which have gained interest among researchers to study their applications in the field of biomedicine, such asanti-inflammatory, anticancer, and antimicrobial applications. In this study, the turmeric extract was prepared and mixed with cerium nitrate hexahydrate, stirred continuously to obtain a homogeneous solution and then heated on a hot plate to get the supernatant evaporated, then calcinated at 600°C to obtain the cerium oxide nanoparticles. Characterization of synthesized cerium oxide nanoparticles through Scanning Electron Microscopy determined the particle size to be in the range of 70 nm to 250 nm. Energy Dispersive X-Ray Spectroscopy determined the elemental composition of cerium and oxygen. Individual particles were identified through the characterization of cerium oxide nanoparticles using Field Emission Scanning Electron Microscopy, in which the particles were determined to be spherical and in the size of around 70 nm. The presence of cerium oxide was assured by analyzing the spectrum obtained through the characterization of cerium oxide nanoparticles by Fourier Transform Infrared Spectroscopy. The crystal structure of cerium oxide nanoparticles was determined to be face-centered cubic by analyzing the peaks obtained through theX-Ray Diffraction method. The crystal size of cerium oxide nanoparticles was determined to be around 13 nm by using the Debye Scherer equation. This study confirmed the synthesis of cerium oxide nanoparticles using turmeric extract.

Keywords: antioxidant, characterization, cerium oxide, synthesis, turmeric

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Authors: Maricarmen Herrera, Pierre Chymkowitch, Joe Robertson, Jens Eriksson, Jorrit Enserink

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tRNA genes are transcribed by RNA polymerase III. During recent years, it has become clear that tDNA transcription fluctuates during the cell cycle. However, the mechanism by which the cell cycle controls the amplitude of tDNA transcription remains unknown. We found that the cyclin Clb5 recruits the cyclin dependent kinase Cdk1 to tRNA genes to sharply increase tRNA synthesis during a brief interval in the cell cycle. We show that Cdk1 promotes the interaction of TFIIIB with TFIIIC, that it stimulates the recruitment of TFIIIC to tRNA genes, that it prevents the formation of an overly stable TFIIIB-tDNA complex and that it augments the dynamics of RNA polymerase III. Furthermore, we identify Bdp1 as a novel Cdk1 substrate, and phosphorylation of Bdp1 is required for the cell cycle-dependent increase in tDNA transcription. In addition, we show that phosphorylation of the Cdk1 substrate Nup60 mediates formation of a Nup60-Nup2 complex at tRNA genes, which is also required for cell cycle-dependent tDNA transcription. Together, our findings indicate that Cdk1 activity gates tRNA synthesis by regulating the dynamics of the TFIIIB-TFIIIC-RNAPIII complex, and that it may promote the formation of a nuclear pore microenvironment conducive to efficient tDNA transcription.

Keywords: Cdk1, cell cycle, RNAPIII machinery, tRNA

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Authors: Petri Solanti, Russell Klein

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Many designers are asking for an automated path from an abstract mathematical MATLAB model to a high-quality Register-Transfer Level (RTL) hardware description. Manual transformations of MATLAB or intermediate code are needed, when the design abstraction is changed. Design conversion is problematic as it is multidimensional and it requires many different design steps to translate the mathematical representation of the desired functionality to an efficient hardware description with the same behavior and configurability. Yet, a manual model conversion is not an insurmountable task. Using currently available design tools and an appropriate design methodology, converting a MATLAB model to efficient hardware is a reasonable effort. This paper describes a simple and flexible design methodology that was developed together with several design teams.

Keywords: design methodology, high-level synthesis, MATLAB, verification

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Authors: S. Sharma, U. Batra, S. Kapoor, A. Dua

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In this study, the effects and interactions of reaction time and capping agent assistance during sol-gel synthesis of magnesium substituted hydroxyapatite nanopowder (MgHA) on hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) ratio, Ca/P ratio and mean crystallite size was examined experimentally as well as through statistical analysis. MgHA nanopowders were synthesized by sol-gel technique at room temperature using aqueous solution of calcium nitrate tetrahydrate, magnesium nitrate hexahydrate and potassium dihydrogen phosphate as starting materials. The reaction time for sol-gel synthesis was varied between 15 to 60 minutes. Two process routes were followed with and without addition of triethanolamine (TEA) in the solutions. The elemental compositions of as-synthesized powders were determined using X-ray fluorescence (XRF) spectroscopy. The functional groups present in the as-synthesized MgHA nanopowders were established through Fourier Transform Infrared Spectroscopy (FTIR). The amounts of phases present, Ca/P ratio and mean crystallite sizes of MgHA nanopowders were determined using X-ray diffraction (XRD). The HA content in biphasic mixture of HA and β-TCP and Ca/P ratio in as-synthesized MgHA nanopowders increased effectively with reaction time of sols (p < 0.0001, two way Anova), however, these were independent of TEA addition (p > 0.15, two way Anova). The MgHA nanopowders synthesized with TEA assistance exhibited 14 nm lower crystallite size (p < 0.018, 2 sample t-test) compared to the powder synthesized without TEA assistance.

Keywords: capping agent, hydroxyapatite, regression analysis, sol-gel, 2- sample t-test, two-way analysis of variance (ANOVA)

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Authors: Gabor Varga, Krisztina Karadi, Zoltan Konya, Akos Kukovecz, Pal Sipos, Istvan Palinko

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Nickel can efficiently replace palladium in the Heck, Suzuki and Negishi reactions. This study focuses on the synthesis and catalytic application of Ni(II)-containing layered double hydroxides (LDHs) and layered triple hydroxides (LTHs). Our goals were to incorporate Ni(II) ions among the layers of LDHs or LTHs, or binding it to their surface or building it into their layers in such a way that their catalytic activities are maintained or even increased. The LDHs and LTHs were prepared by the co-precipitation method using ethylene glycol as co-solvent. In several cases, post-synthetic modifications (e.g., thermal treatment) were performed. After optimizing the synthesis conditions, the composites displayed good crystallinity and were free of byproducts. The success of the syntheses and the post-synthetic modifications was confirmed by relevant characterization methods (XRD, SEM, SEM-EDX and combined IR techniques). Catalytic activities of the produced and well-characterized solids were investigated through the Heck reaction. The composites behaved as efficient, recyclable catalysts in the Heck reaction between 4-bromoanisole and styrene. Through varying the reaction parameters, we were able to obtain acceptable conversions under mild conditions. Our study highlights the possibility of the application of Ni(II)-containing composites as efficient catalysts in coupling reactions.

Keywords: layered double hydroxide, layered triple hydroxide, heterogeneous catalysis, heck reaction

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Authors: Getachew Demeissie Ayalew, Yongtao Sun, Yang Yang

Abstract:

The spiral welded pipe manufacturing industry requires strict production standards for automated grinders for welding seams. However, traditional grinding machines in this sector are insufficient due to a lack of quality control protocols and inconsistent performance. This research aims to improve the quality of spiral welded pipes by developing intelligent automated abrasive belt grinding equipment. The system has equipped with six degrees of freedom (6 DOF) KUKA KR360 industrial robots, enabling concurrent grinding operations on both internal and external welds. The grinding robot control system is designed with a PLC, and a human-machine interface (HMI) system is employed for operations. The system includes an electric speed controller, data connection card, DC driver, analog amplifier, and HMI for input data. This control system enables the grinding of spiral welded pipe. It ensures consistent production quality and cost-effectiveness by reducing the product life cycle and minimizing risks in the working environment.

Keywords: Intelligent Systems, Spiral Welded Pipe, Grinding, Industrial Robot, End-Effector, PLC Controller System, 3D Laser Sensor, HMI.

Procedia PDF Downloads 297

Authors: Parisi L., Hamili D., Azlan N.

Abstract:

The aim of this study was to design and simulate a particular type of Asynchronous State Machine (ASM), namely a ‘traffic light controller’ (TLC), operated at a frequency of 0.5 Hz. The design task involved two main stages: firstly, designing a 4-bit binary counter using J-K flip flops as the timing signal and subsequently, attaining the digital logic by deploying ASM design process. The TLC was designed such that it showed a sequence of three different colours, i.e. red, yellow and green, corresponding to set thresholds by deploying the least number of AND, OR and NOT gates possible. The software Multisim was deployed to design such circuit and simulate it for circuit troubleshooting in order for it to display the output sequence of the three different colours on the traffic light in the correct order. A clock signal, an asynchronous 4-bit binary counter that was designed through the use of J-K flip flops along with an ASM were used to complete this sequence, which was programmed to be repeated indefinitely. Eventually, the circuit was debugged and optimized, thus displaying the correct waveforms of the three outputs through the logic analyzer. However, hazards occurred when the frequency was increased to 10 MHz. This was attributed to delays in the feedback being too high.

Keywords: asynchronous state machine, traffic light controller, circuit design, digital electronics

Procedia PDF Downloads 429

Authors: Sarai Guerrero, Lijia Liu

Abstract:

Zinc gallogermanate (ZGGO) is a persistent phosphor that can emit in the near infrared (NIR) range once dopped with Cr³⁺ enabling its use for in-vivo deep-tissue bio-imaging. Such a property also allows for its application in cancer diagnosis and therapy. Given this, work into developing a synthetic procedure that can be done using common laboratory instruments and equipment as well as understanding ZGGO overall, is in demand. However, the ZGGO nanoparticles must have a size compatible for cell intake to occur while still maintaining sufficient photoluminescence. The nanoparticle must also be made biocompatible by functionalizing the surface for hydrophilic solubility and for high particle uniformity in the final product. Additionally, most research is completed on doped ZGGO, leaving a gap in understanding the base form of ZGGO. It also leaves a gap in understanding how doping affects the synthesis of ZGGO. In this work, the first step of optimizing the particle size via the crystalline size of ZGGO was done with undoped ZGGO using the organic acid, oleic acid (OA) for organic ligand-assisted biphasic hydrothermal synthesis. The effects of this synthesis procedure on ZGGO’s crystallinity were evaluated using Powder X-Ray Diffraction (PXRD). OA was selected as the capping ligand as experiments have shown it beneficial in synthesizing sub-10 nm zinc gallate (ZGO) nanoparticles as well as palladium nanocrystals and magnetite (Fe₃O₄) nanoparticles. Later it is possible to substitute OA with a different ligand allowing for hydrophilic solubility. Attenuated Total Reflection Fourier-Transform Infrared (ATR-FTIR) was used to investigate the surface of the nanoparticle to investigate and verify that OA had capped the nanoparticle. PXRD results showed that using this procedure led to improved crystallinity, comparable to the high-purity reagents used on the ZGGO nanoparticles. There was also a change in the crystalline size of the ZGGO nanoparticles. ATR-FTIR showed that once capped ZGGO cannot be annealed as doing so will affect the OA. These results point to this new procedure positively affecting the crystallinity of ZGGO nanoparticles. There are also repeatable implying the procedure is a reliable source of highly crystalline ZGGO nanoparticles. With this completed, the next step will be working on substituting the OA with a hydrophilic ligand. As these ligands effect the solubility of the nanoparticle as well as the pH that the nanoparticles can dissolve in, further research is needed to verify which ligand is best suited for preparing ZGGO for bio-imaging.

Keywords: biphasic hydrothermal synthesis, crystallinity, oleic acid, zinc gallogermanate

Procedia PDF Downloads 133

Authors: Sumara Khursheed, Jitendra Sharma

Abstract:

The present work reports synthesis of nanocomposites (NCs) of phosphor (KCaVO4:Sm3+) embedded poly(methylmethacrylate) (PMMA) using solution casting method and their optical properties measurements for their possible application in making flexible luminescent films. X-ray diffraction analyses were employed to obtain the structural parameters as crystallinity, shape and size of the obtained NCs. The emission and excitation spectra were obtained using Photoluminescence spectroscopy to quantify the spectral properties of these fluorescent polymer/phosphor films. Optical energy gap has been estimated using UV-VIS spectroscopy while differential scanning calorimetry (DSC) was exploited to measure the thermal properties of the NC films in terms of their thermal stability, glass transition temperature and degree of crystallinity etc.

Keywords: nanocomposites, luminescence, XRD, differential scanning calorimetry, PMMA

Procedia PDF Downloads 169

Authors: M. Bahgat, F. M. Awan, H. A. Hanafy, O. N. Alzeghaibi

Abstract:

Strontium hexaferrite (SrFe12O19; Sr-ferrite) is one of the well-known materials for permanent magnets. In this study, M-type strontium ferrite was prepared by following the conventional ceramic method from steelmaking by-product. Initial materials; SrCO3 and by-product, were mixed together in the composition of SrFe12O19 in different Sr/Fe ratios. The mixtures of these raw materials were dry-milled for 6h. The blended powder was pre-sintered (i.e. calcination) at 1000°C for different times periods, then cooled down to room temperature. These pre-sintered samples were re-milled in a dry atmosphere for 1h and then fired at different temperatures in atmospheric conditions, and cooled down to room temperature. The produced magnetic powder has a dense hexagonal grain shape structure. The calculated energy product values for the produced samples ranged from 0.3 to 2.4 MGOe.

Keywords: hard magnetic materials, ceramic route, strontium ferrite, synthesis

Procedia PDF Downloads 324

Authors: Mayuri Gandhi, Nayan Agrawal, Harshita Bhatia

Abstract:

In the present work, cerium fluoride (CeF3) was selected as the host material because of its high density, fast response and high radiation resistance, efficient absorption and energy transfer by host (to activator). For the synthesis of CeF3 nanoparticles doped with Sm3+ ion, co-precipitation route was employed. Thus for optimum results, concentration dependent studies of the fluorescence of Sm3+ was carried out. The photoluminescence gave emissions in both visible as well as the NIR region and therefore it can have its application in solar cells, where it can absorb a large spectrum of energy. CeF3:Sm3+ nanoparticles were carefully incorporated in a suitable polymer matrix in order to demonstrate a variety of applications to improve the performance of the polymer materials and use it to develop high grade optoelectronic devices such as LEDs, security labelling, lasers, displays, biological imaging, etc.

Keywords: bioimaging, cerium fluoride, NIR emission, samarium

Procedia PDF Downloads 418