Search results for: magnetic field generation

Authors: Mark Watson, J.-F. Bousquet, Adam Forget

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A magnetic induction based underwater communication link is evaluated using an analytical model and a custom Finite-Difference Time-Domain (FDTD) simulation tool. The analytical model is based on the Sommerfeld integral, and a full-wave simulation tool evaluates Maxwell’s equations using the FDTD method in cylindrical coordinates. The analytical model and FDTD simulation tool are then compared and used to predict the system performance for various transmitter depths and optimum frequencies of operation. To this end, the system bandwidth, signal to noise ratio, and the magnitude of the induced voltage are used to estimate the expected channel capacity. The models show that in seawater, a relatively low-power and small coils may be capable of obtaining a throughput of 40 to 300 kbps, for the case where a transmitter is at depths of 1 to 3 m and a receiver is at a height of 1 m.

Keywords: magnetic induction, FDTD, underwater communication, Sommerfeld

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Authors: Young-Min Kang

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M-type Sr-hexaferrites (SrFe12O19) is one of the most utilized materials in permanent magnets due to their low price, outstanding chemical stability, and appropriate hard magnetic properties. For a M-type Sr-hexaferrite with a saturation magnetization (MS) of ~74.0 emu/g the practical limits of remanent flux density (Br) and maximum energy product (BH) max are ~4.6 kG and ~5.3 MGOe. Meanwhile, W-type hexaferrite (SrFe18O27) with higher MS ~81emu/g can be a good candidate for the development of enhanced ferrite magnet. However the W-type hexaferrite is stable at the temperature over 1350 ºC in air, and thus it is hard to control grain size and the coercivity. We report here high-MS M-W composite hexaferrites synthesized at 1250 ºC in air by doping Ca, Co, Mn, and Zn into the hexaferrite structures. The hexaferrites samples of stoichiometric SrFe12O19 (SrM) and Ca-Co-Mn-Zn doped hexaferrite (Sr0.7Ca0.3Fen-0.6Co0.2Mn0.2Zn0.2Oa) were prepared by conventional solid state reaction process with varying Fe content (10 ≤ n ≤ 17). Analysis by x-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) were performed for phase identification and microstructural observation respectively. Magnetic hysteresis curves were measured using vibrating sample magnetometer (VSM) at room temperature (300 K). Single M-type phase could be obtained in the non-doped SrM sample after calcinations at the range of 1200 ºC ~ 1300 ºC, showing MS in the range of 72 ~ 72.6 emu/g. The Ca-Co-Mn-Zn doped SrM with Fe content, 10 ≤ n ≤ 13, showed both M and W-phases peaks in the XRD after respective calcinations at 1250 ºC. The sample with n=13 showed the MS of 70.7, 75.3, 78.0 emu/g, respectively, after calcination at 1200, 1250, 1300 ºC. The high MS over that of non-doped SrM (~72 emu/g) is attributed to the volume portion of W-phase. It is also revealed that the high MS W-phase could not formed if only one of the Ca, Co, Zn is missed in the substitution. These elements are critical to form the W-phase at the calcinations temperature of 1250 ºC, which is 100 ºC lower than the calcinations temperature for non-doped Sr-hexaferrites.

Keywords: M-type hexaferrite, W-type hexaferrite, saturation magnetization, low-temperature synthesis

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Authors: Esubalew Yehualaw Melaku

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In this study, two basic geophysical methods are applied for mapping the groundwater aquifer system in the Gode area along the Guder River, northeast of Hosanna town, near the western margin of the Central Main Ethiopian Rift. The main target of the study is to map the potential aquifer zone and investigate the groundwater potential for current and future development of the resource in the Gode area. The geophysical methods employed in this study include, Vertical Electrical Sounding (VES) and magnetic survey techniques. Electrical sounding was used to examine and map the depth to the potential aquifer zone of the groundwater and its distribution over the area. On the other hand, a magnetic survey was used to delineate contact between lithologic units and geological structures. The 2D magnetic modeling and the geoelectric sections are used for the identification of weak zones, which control the groundwater flow and storage system. The geophysical survey comprises of twelve VES readings collected by using a Schlumberger array along six profile lines and more than four hundred (400) magnetic readings at about 10m station intervals along four profiles and 20m along three random profiles. The study result revealed that the potential aquifer in the area is obtained at a depth range from 45m to 92m. This is the response of the highly weathered/ fractured ignimbrite and pumice layer with sandy soil, which is the main water-bearing horizon. Overall, in the neighborhood of four VES points, VES- 2, VES- 3, VES-10, and VES-11, shows good water-bearing zones in the study area.

Keywords: vertical electrical sounding, magnetic survey, aquifer, groundwater potential

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Authors: K. K. Riabchenko, T. V Rybitskaya, A. A. Starostenko

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Sper Charm-Tau Factory is a double ring e+e- collider to be operated in the center-of-mass energy range from 2 to 6 GeV, with a peak luminosity of about 1035 cm-2s-1 (Crab Waist collision) and with longitudinally polarized electrons at the IP (interaction point). One of the important elements of the cτ-factory is the superconducting two-aperture quadrupole of the final focus. It was decided to make a full-scale prototype quadrupole. The main objectives of our study included: 1) 3D modeling of the quadrupole in the Opera program, 2) Optimization of the geometry of the quadrupole lens, 3) Study of the influence of magnetic properties and geometry of a quadrupole on integral harmonics. In addition to this, the ways of producing unwanted harmonics have been studied. In the course of this work, a 3D model of a two-aperture iron superconducting quadrupole lens was created. A three-dimensional simulation of the magnetic field was performed, and the geometrical parameters of the lens were selected. Calculations helped to find sources of possible errors and methods for correcting unwanted harmonics. In addition to this, calculations show that there are no obstacles to the production of a prototype lens.

Keywords: super cτ-factory, final focus, twin aperture quadrupole lens, integral harmonics

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Authors: Louvill M. Ozarraga

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this study was designed to ascertain the concept of the revenue generation system of Bacolod, Lanao del Norte, through the completely enumerated elected officials and permanent employees sample respondents. The pertinent data were obtained through the use of a structured questionnaire and with the help of key informants. The study utilized a cross-sectional survey design to analyze and interpret the data using frequency count, percentage distribution, and weighted mean. For the major findings, the local revenue generation of the Municipality has increased by Php 4,465,394.21, roughly 73.52%, from the years 2018 to 2020. Administrative activities help the Municipality cope with development, namely, the issuance of ordinances, personnel augmentation, and collection strategies. Moreover, respondents were undecided about whether revenue generation contributed to infrastructures and purchases of assets. The majority of the respondents agreed that the municipality’s local revenue generation contributes to the social welfare of its constituents. Also, the respondents disagreed that locally generated revenue augments the 20% development fund. The study revealed that there is a big difference between the 2018 and 2020 Real Property Tax (RPT) collection. No committee was created to monitor and supervise the municipal revenue generation system. The Municipality, through a partnership with TESDA, provides skilled-job opportunity to its constituents and participants

Keywords: Local Revenue Generation: Its Contribution To The Development Of The Municipality Of Bacolod, Lanao Del Sur

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Authors: Krishna Prasad Maity, Narendra Tanty, Ananya Patra, V. Prasad

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Carbon nanotube (CNT) is a well-known material for very good electrical, thermal conductivity and high tensile strength. Because of that, it’s widely used in many fields like nanotechnology, electronics, optics, etc. In last two decades, polyaniline (PANI) with CNT and functionalized CNT (fCNT) have been promising materials in application of gas sensing, electromagnetic shielding, electrode of capacitor etc. So, the study of electrical conductivity of PANI/CNT and PANI/fCNT is important to understand the charge transport and interaction between PANI and CNT in the composite. It is observed that a transition in magnetoresistance (MR) with lowering temperature, increasing magnetic field and decreasing CNT percentage in CNT/PANI composite. Functionalization of CNT prevent the nanotube aggregation, improves interfacial interaction, dispersion and stabilized in polymer matrix. However, it shortens the length, breaks C-C sp² bonds and enhances the disorder creating defects on the side walls. We have studied electrical resistivity and MR in PANI with CNT and fCNT composites for different weight percentages down to the temperature 4.2K and up to magnetic field 5T. Resistivity increases significantly in composite at low temperature due to functionalization of CNT compared to only CNT. Interestingly a transition from negative to positive magnetoresistance has been observed when the filler is changed from pure CNT to functionalized CNT after a certain percentage (10wt%) as the effect of more disorder in fCNT/PANI composite. The transition of MR has been explained on the basis of polaron-bipolaron model. The long-range Coulomb interaction between two polarons screened by disorder in the composite of fCNT/PANI, increases the effective on-site Coulomb repulsion energy to form bipolaron which leads to change the sign of MR from negative to positive.

Keywords: coulomb interaction, magnetoresistance transition, polyaniline composite, polaron-bipolaron

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Authors: J. C. Riaño-Rojas, J. D. Alzate-Cardona, E. Restrepo-Parra

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In this work, a study of generic magnetic nanoparticles varying the metric space is presented. As the metric space is changed, the nanoparticle form and the inner product are also varied, since the energetic scale is not conserved. This study is carried out using Monte Carlo simulations combined with the Wolff embedding and Metropolis algorithms. The Metropolis algorithm is used at high temperature regions to reach the equilibrium quickly. The Wolff embedding algorithm is used at low and critical temperature regions in order to reduce the critical slowing down phenomenon. The ions number is kept constant for the different forms and the critical temperatures using finite size scaling are found. We observed that critical temperatures don't exhibit significant changes when the metric space was varied. Additionally, the effective dimension according the metric space was determined. A study of static behavior for reaching the static critical exponents was developed. The objective of this work is to observe the behavior of the thermodynamic quantities as energy, magnetization, specific heat, susceptibility and Binder's cumulants at the critical region, in order to demonstrate if the magnetic nanoparticles describe their magnetic interactions in the Euclidean space or if there is any correspondence in other metric spaces.

Keywords: nanoparticles, metric, Monte Carlo, critical behaviour

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Authors: H. H. Lee, D. Y. Kim, S. W. Lee, J. H. Kim, J. H. Kim, W. Z. Oh, S. J. Choi

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In recent years, carbon nanotubes (CNTs) have been widely employed as a sorbent for the removal of various metal ions from water due to their unique properties such as large surface area, light mass density, high porous and hollow structure, and strong interaction between the pollutant molecules and CNTs. To apply CNTs to the sorption of Cs+ from aqueous solutions, they must first be functionalized to increase their hydrophilicity and therefore, enhance their applicability to the sorption of polar and relatively low-molecular-weight species. The objective of this study is to investigate the preparation of magnetically separable multi-walled carbon nanotubes (MWCNTs-m) as a sorbents for the removal of Cs+ from aqueous solutions. The MWCNTs-m was prepared using pristine MWCNTs and iron precursor Fe(acac)3. For the selective removal of Cs+ from aqueous solutions, the MWCNTs-m was functionalized with zinc hexacyanoferrate (MWCNTs-m-ZnFC). The physicochemical properties of the synthesized sorbents were characterized with various techniques, including transmission electron microscopy (TEM), specific surface area analysis, Fourier transform-infrared (FT-IR) spectroscopy, and vibrating-sample magnetometer. The MWCNTs-m-ZnFC was found to be easily separated from aqueous solutions by using magnetic field. The MWCNTs-m-ZnFC exhibited a high capacity for sorbing Cs+ from aqueous solutions because of their strong affinity for Cs+ and specific surface area. The sorption ability of the MWCNTs-m-ZnFC for Cs+ was maintained even in the presence of co-existing ions (Na+). Considering these results, the CNT-m-ZnFCs have great potential for use as an effective sorbent for the selective removal of radioactive Cs+ ions from aqueous solutions.

Keywords: multi-walled carbon nanotubes, magnetic materials, cesium, zinc hexacyanoferrate, sorption

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Authors: Hideyuki Onodera, Ryoji Imai, Masahiro Sakai

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Explosions have occurred in incineration plants in conveyors, ash pits, and other locations. The cause of such explosions is thought to be the reaction of metallic aluminum contained in the ash with water used to cool the ash and prevent scattering, resulting in the generation of hydrogen. Given this background, conveyors and other equipment have been damaged by explosions, which has hindered the stable operation of incineration plants. In addition, workers may be injured by equipment explosions, creating an unsafe situation. To remedy these problems, it is necessary to devise a way to prevent hydrogen explosions from occurring. To overcome this problem, we conducted a hydrogen generation reaction experiment using simulated incinerator ash powder containing aluminum, calcium oxide, and water and confirmed that conditions exist to stop the hydrogen generation reaction. The results of this research may contribute to the suppression of hydrogen explosions at incineration plants.

Keywords: waste incinerated ash, aluminum, water, hydrogen, suppression of hydrogen generation, incineration plant

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Authors: Kang-Hyuk Lee, Wei Yan, Sang-Im Yoo

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Recently, Ca₁₋ₓLaₓFe₁₂O₁₉ (Ca-La M-type) hexaferrites have been reported to possess higher crystalline anisotropy compared with SrFe₁₂O₁₉ (Sr M-type) hexaferrite without reducing its saturation magnetization (Ms), resulting in higher coercivity (Hc). While iron deficiency is known to be helpful for the growth and the formation of NiZn spinel ferrites, the effect of iron deficiency in Ca-La M-type hexaferrites has never been reported yet. In this study, therefore, we tried to investigate the effect of iron deficiency on the magnetic properties of Ca₀.₅La₀.₅Fe₁₂₋yO₁₉₋δ hexaferrites prepared by solid state reaction. As-calcined powder was pressed into pellets and sintered at 1275~1325℃ for 4 h in air. Samples were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and scanning electron microscope (SEM). Powder XRD analyses revealed that Ca₀.₅La₀.₅Fe₁₂₋yO₁₉₋δ (0.75 ≦ y ≦ 2.15) ferrites calcined at 1250-1300℃ for 12 h in air were composed of single phase without the second phases. With increasing the iron deficiency, y, the lattice parameters a, c and unite cell volumes were decreased first up to y=10.25 and then increased again. The highest Ms value of 77.5 emu/g was obtainable from the sample of Ca₀.₅La₀.₅Fe₁₂₋yO₁₉₋δ sintered at 1300℃ for 4 h in air. Detailed microstructures and magnetic properties of Ca-La M-type hexagonal ferrites will be presented for a discussion

Keywords: Ca-La M-type hexaferrite, magnetic properties, iron deficiency, hexaferrite

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Authors: Ozge Karayalçin

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This study tries to find out the reasons for the integration problems of third generation Dutch-Turkish youngsters by particularly focusing on the socio-cultural and socio-economic situations of these people in the Netherlands. The results obtained from the field research are summed up under four sections. These four sections are education and language, labour market, cultural factors, religion, and nationality. The underlying reasons of the integration problems are reflected from two different perspectives. The first one is the effects of social and economic enforcements implemented on the Turkish immigrant society. The second one is the traditional Turkish values that are quite different from Dutch values. The problems experienced by third generation Turkish origin Dutch youngsters are not one-sided. To conclude, solution-oriented advisements are asserted.

Keywords: acculturation levels, Dutch-Turkish youngsters, integration, transnational migrants, identity conflicts

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Authors: Lolade Siyonbola

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Nigerians are often celebrated as being the most educated cultural group in America. The cultural values and history that have led to this reality are particular to a generation that came of age post colonialism. Many of these cultural values have been passed down from post-colonial parent to millennial child, but most have not. This study, based on interviews and surveys of Nigerian millennials and their parents in the United States, explores the degree to which identity has been eroded in the millennial generation due to a lack of imparted cultural values and knowledge from the previous generation. Most of the subjects do not speak their native language or identify with their cultural heritage sufficiently to build ties with their native land. Most are experiencing some degree of identity crisis, and therefore limited self-actualization, with little to no support; as there are few successful tools available to this population. If governmental programs to reverse these trends are not implemented within this generation, the implications to the individual, family and home nation (Nigeria), will be felt for generations to come.

Keywords: identity, culture, self-actualization, social identity theory, migration, transnationalism, value systems

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Authors: Lei Lei, Hongbo Zhang, Donald J. Bergstrom, Bing Zhang, K. Y. Song, W. J. Zhang

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This paper presents a model for a modified T-junction device for microspheres generation. The numerical model is developed using a commercial software package: COMSOL Multiphysics. In order to test the accuracy of the numerical model, multiple variables, such as the flow rate of cross-flow, fluid properties, structure, and geometry of the microdevice are applied. The results from the model are compared with the experimental results in the diameter of the microsphere generated. The comparison shows a good agreement. Therefore the model is useful in further optimization of the device and feedback control of microsphere generation if any.

Keywords: CFD modeling, validation, microsphere generation, modified T-junction

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Authors: Binyam Teferi

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In this paper, a theoretical analysis of blood flow in the presence of thermal radiation and chemical reaction under the influence of time dependent magnetic field intensity has been studied. The unsteady non linear partial differential equations of blood flow considers time dependent stretching velocity, the energy equation also accounts time dependent temperature of vessel wall, and concentration equation includes time dependent blood concentration. The governing non linear partial differential equations of motion, energy, and concentration are converted into ordinary differential equations using similarity transformations solved numerically by applying ode45. MATLAB code is used to analyze theoretical facts. The effect of physical parameters viz., permeability parameter, unsteadiness parameter, Prandtl number, Hartmann number, thermal radiation parameter, chemical reaction parameter, and Schmidt number on flow variables viz., velocity of blood flow in the vessel, temperature and concentration of blood has been analyzed and discussed graphically. From the simulation study, the following important results are obtained: velocity of blood flow increases with both increment of permeability and unsteadiness parameter. Temperature of the blood increases in vessel wall as Prandtl number and Hartmann number increases. Concentration of the blood decreases as time dependent chemical reaction parameter and Schmidt number increases.

Keywords: stretching velocity, similarity transformations, time dependent magnetic field intensity, thermal radiation, chemical reaction

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Authors: Mohsen Torabi, Nader Karimi, Kaili Zhang

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This work aims to provide a comprehensive study on the heat transfer and entropy generation rates of a horizontal channel partially filled with a porous medium which experiences internal heat generation or consumption due to exothermic or endothermic chemical reaction. The focus has been given to the local thermal non-equilibrium (LTNE) model. The LTNE approach helps us to deliver more accurate data regarding temperature distribution within the system and accordingly to provide more accurate Nusselt number and entropy generation rates. Darcy-Brinkman model is used for the momentum equations, and constant heat flux is assumed for boundary conditions for both upper and lower surfaces. Analytical solutions have been provided for both velocity and temperature fields. By incorporating the investigated velocity and temperature formulas into the provided fundamental equations for the entropy generation, both local and total entropy generation rates are plotted for a number of cases. Bifurcation phenomena regarding temperature distribution and interface heat flux ratio are observed. It has been found that the exothermicity or endothermicity characteristic of the channel does have a considerable impact on the temperature fields and entropy generation rates.

Keywords: entropy generation, exothermicity or endothermicity, forced convection, local thermal non-equilibrium, analytical modelling

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Authors: Hüseyin Altubaş, Hasret Aktaş, A. Mücahid Zengin

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Children determine the direction of the power of consumption. They affect the decisions of their parents but they also reached to a significant purchasing power themselves. Children, who are turning interactive behavior to normal behavior are becoming the decision makers in a company’s survival. Companies that analyze this effective target audience can communicate successfully with children. Children, who are interactive individuals, are closer to advertising. They are almost talking better with advertising. They are not afraid to express their likings, as well as their dislikes. Children have an interactive lifestyle and they were exposed to the vast changes in technology after year 2000. They do not know a life without internet, they spend mobile life in internet. This Z generation is the new determinants of brands. Z generation finds it appropriate to be brand ambassadors and they completely changed traditional media and traditional consumer behavior. These children live social reality with virtual reality and they feed brands differently. Brands that interact with Z generation are affected by this feeding positively, while brands that keep interaction in traditional levels are affected negatively. In this research we examine the communication, advertising and brand behaviors of Z generation. We especially analyze this generation’s interaction with social media brands and their interactive attitudes.

Keywords: social media, Z generation, children, advertising, brand choice

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Authors: Sebwato Nasurudiin, Akimasa Yoshikawa, Ahmed Elsaid, Ayman Mahrous

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This study examines the correlation between the amplitude of Forbush Decreases (FDs) detected by the Mountain Chacaltaya neutron monitor and the solar wind electric field (E). Forbush Decreases, characterized by sudden drops in cosmic ray intensity, are typically associated with interplanetary coronal mass ejections (ICMEs) and high-speed solar wind streams. The Mountain Chacaltaya neutron monitor, located at a high altitude in Bolivia, offers an optimal setting for observing cosmic ray variations. The solar wind electric field, influenced by the solar wind velocity and interplanetary magnetic field, significantly impacts cosmic ray transport in the heliosphere. By analyzing neutron monitor data alongside solar wind parameters, we found a high correlation between E and FD amplitudes with a correlation factor of nearly 87%. The findings enhance our understanding of space weather processes, cosmic ray modulation, and solar-terrestrial interactions, providing valuable insights for predicting space weather events and mitigating their technological impacts. This study contributes to the broader astrophysics field by offering empirical data on cosmic ray modulation mechanisms.

Keywords: cosmic rays, Forbush decrease, solar wind, neutron monitor

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Authors: Elisha Didam Markus, Thapelo Maqame

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This paper focuses on studying the effects of magnetism on water and their impact to plant growth. Magnetic fields are known to induce higher rate of biochemical reaction and therefore can be used for growth related reactions in plants. For the purpose of this study, two 2 litres bottles were taken, one with two opposite poles magnets (500 mT) one on top and one at the bottom of the bottle. Another bottle was not altered in any way (used as control). Each bottle contained tap water stored up for 24 hours. Plants planted into different pots were watered using water from these bottles. Four pots with soil and manure equally mixed were used and equal volume of radish berry seeds were planted. Two pots were watered with magnetised water and the other two with normal tap water. The developments of plants were monitored in terms of their lengths for a period of 21 days. After 21 days, the lengths of plants watered with magnetised water were found to be 5.6% longer than those watered with tap water.

Keywords: magnetised water, radish berry, growth percentage, magnetic fields

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Authors: Kamal Upadhyay, Zhou Hua, Yu Rui

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This paper aims to improve the streamline linked with the flow field and cavitation on the valve sleeve. We observed that local pressure fluctuation produces a low-pressure zone, central to the formation of vapor volume fraction within the valve chamber led to air-bubbles (or cavities). Thus, it allows simultaneously to a severe negative impact on the inner surface and lifespan of the valve sleeves. Cavitation reduction is a vitally important issue to pressure control valves. The optimization of the flow field is proposed in this paper to reduce the cavitation of valve sleeves. In this method, the inner wall of the valve sleeve is changed from a cylindrical surface to the conical surface, leading to the decline of the fluid flow velocity and the rise of the outlet pressure. Besides, the streamline is distributed inside the sleeve uniformly. Thus, the bubble generation is lessened. The fluid models are built and analysis of flow field distribution, pressure, vapor volume and velocity was carried out using computational fluid dynamics (CFD) and numerical technique. The results indicate that this structure can suppress the cavitation of valve sleeves effectively.

Keywords: streamline, cavitation, optimization, computational fluid dynamics

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Authors: Jae Won Lee, Kyung Hyun Min, Hong Jae Lee, Sang Cheon Lee

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To date, imaging techniques have attracted much attention in medicine because the detection of diseases at an early stage provides greater opportunities for successful treatment. Consequently, over the past few decades, diverse imaging modalities including magnetic resonance (MR), positron emission tomography, computed tomography, and ultrasound (US) have been developed and applied widely in the field of clinical diagnosis. However, each of the above-mentioned imaging modalities possesses unique strengths and intrinsic weaknesses, which limit their abilities to provide accurate information. Therefore, multimodal imaging systems may be a solution that can provide improved diagnostic performance. Among the current medical imaging modalities, US is a widely available real-time imaging modality. It has many advantages including safety, low cost and easy access for patients. However, its low spatial resolution precludes accurate discrimination of diseased region such as cancer sites. In contrast, MR has no tissue-penetrating limit and can provide images possessing exquisite soft tissue contrast and high spatial resolution. However, it cannot offer real-time images and needs a comparatively long imaging time. The characteristics of these imaging modalities may be considered complementary, and the modalities have been frequently combined for the clinical diagnostic process. Biominerals such as calcium carbonate (CaCO3) and calcium phosphate (CaP) exhibit pH-dependent dissolution behavior. They demonstrate pH-controlled drug release due to the dissolution of minerals in acidic pH conditions. In particular, the application of this mineralization technique to a US contrast agent has been reported recently. The CaCO3 mineral reacts with acids and decomposes to generate calcium dioxide (CO2) gas in an acidic environment. These gas-generating mineralized nanoparticles generated CO2 bubbles in the acidic environment of the tumor, thereby allowing for strong echogenic US imaging of tumor tissues. On the basis of this previous work, it was hypothesized that the loading of MR contrast agents into the CaCO3 mineralized nanoparticles may be a novel strategy in designing a contrast agent for dual imaging. Herein, CaCO3 mineralized nanoparticles that were capable of generating CO2 bubbles to trigger the release of entrapped MR contrast agents in response to tumoral acidic pH were developed for the purposes of US and MR dual-modality imaging of tumors. Gd2O3 nanoparticles were selected as an MR contrast agent. A key strategy employed in this study was to prepare Gd2O3 nanoparticle-loaded mineralized nanoparticles (Gd2O3-MNPs) using block copolymer-templated CaCO3 mineralization in the presence of calcium cations (Ca2+), carbonate anions (CO32-) and positively charged Gd2O3 nanoparticles. The CaCO3 core was considered suitable because it may effectively shield Gd2O3 nanoparticles from water molecules in the blood (pH 7.4) before decomposing to generate CO2 gas, triggering the release of Gd2O3 nanoparticles in tumor tissues (pH 6.4~7.4). The kinetics of CaCO3 dissolution and CO2 generation from the Gd2O3-MNPs were examined as a function of pH and pH-dependent in vitro magnetic relaxation; additionally, the echogenic properties were estimated to demonstrate the potential of the particles for the tumor-specific US and MR imaging.

Keywords: calcium carbonate, mineralization, ultrasound imaging, magnetic resonance imaging

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Authors: Tracy B.E. Omorogiuwa

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Understanding the role of social work in improving societal well-being cannot be separated from the place of field education, which is an integral aspect of social work education. Field learning provides students with knowledge and opportunities to experience solving issues in the field and giving them a clue of the practice situation. Despite being a crucial component in social work curriculum, field education occupies a large space in learning outcome, given the issues and challenges pertaining to its purpose and significance in the society. The drive of this paper is to provide insight on the specific ways in which field education has been conceived, realized and valued in the society. Emphasis is on the significance of field instruction; the link with classroom learning; and the structure of field experience in social work education. Given documented analysis and experience, this study intends to contribute to the development of social work curriculum, by analyzing the pattern, issues and challenges fronting the social work field education in the University of Benin, Nigeria.

Keywords: challenges, curriculum, field education, social work education

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Authors: Pyar Singh Jassal, Priti Rani, Rajni Johar

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The adsorption of Pb(II) ions from wastewater using ethylene glycol diglycidyl ether cross-linked magnetic chitosan beads (EGDE-MCB) was carried out by considering a number of parameters. The removal efficiency of the metal ion by magnetic chitosan beads (MCB) and its cross-linked derivatives depended on viz contact time, dose of the adsorbent, pH, temperature, etc. The concentration of Cd( II) at different time intervals was estimated by differential pulse anodic stripping voltammetry (DPSAV) using 797 voltametric analyzer computrace. The adsorption data could be well interpreted by Langmuir and Freundlich adsorption model. The equilibrium parameter, RL values, support that the adsorption (0Keywords: magnetic chitosan beads, ethylene glycol diglycidyl ether, equilibrium parameters, desorption

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Authors: Jayashree Das, V. V. Srinivasu , D. K. Mishra, A. Maity

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Owing to the important potential applications over decades, transition metal (TM: Mn, Fe, Ni, Cu, Cr, V etc.) doped ZnO-based diluted magnetic semiconductors (DMS) always attract research attention for more and newer investigations. One of the interesting aspects of these materials is to study and understand the magnetic property at room temperature properly, which is very crucial to select a material for any related application. In this regard, Electron spin resonance (ESR) study has been proven to be a powerful technique to investigate the spin dynamics of electrons inside the system, which are responsible for the magnetic behaviour of any system. ESR as well as the Raman and Photoluminescence spectroscopy studies are also helpful to study the defects present or created inside the system in the form of oxygen vacancy or cluster instrumental in determining the room temperature ferromagnetic property of transition metal doped ZnO system, which can be controlled through varying dopant concentration, appropriate synthesis technique and sintering of the samples. For our investigation, we synthesised Cu-doped ZnO nanocrystalline samples with composition Zn1-xCux ( 0.005< x < 0.05) by pyrophoric method and sintered at a low temperature of 650 0C. The microwave absorption is studied by the Electron Spin Resonance (ESR) of X-band (9.46 GHz) at room temperature. Systematic analysis of the obtained ESR spectra reveals that all the compositions of Cu-doped ZnO samples exhibit resonance signals of appreciable line widths and g value ~ 2.2, typical characteristic of ferromagnetism in the sample. Raman scattering and the photoluminescence study performed on the samples clearly indicated the presence of pronounced defect related peaks in the respective spectra. Cu doping in ZnO with varying concentration also observed to affect the optical band gap and the respective absorption edges in the UV-Vis spectra. FTIR spectroscopy reveals the Cu doping effect on the stretching bonds of ZnO. To probe into the structural and morphological changes incurred by Cu doping, we have performed XRD, SEM and EDX study, which confirms adequate Cu substitution without any significant impurity phase formation or lattice disorder. With proper explanation, we attempt to correlate the results observed for the structural optical and magnetic behaviour of the Cu-doped ZnO samples. We also claim that our result can be instrumental for appropriate applications of transition metal doped ZnO based DMS in the field of optoelectronics and Spintronics.

Keywords: diluted magnetic semiconductors, electron spin resonance, raman scattering, spintronics.

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Authors: E. S. Kozlyakova, A. A. Eliseev, A. V. Moskin, A. Y. Akhrorov, P. S. Berdonosov, V. A. Dolgikh, K. N. Denisova, P. Lemmens, B. Rahaman, S. Das, T. Saha-Dasgupta, A. N. Vasiliev, O. S. Volkova

Abstract:

Considerable attention has been paid recently to FeTe₂O₅Cl due to reduced dimensionality and frustration in the magnetic subsystem, succession of phase transitions, and multiferroicity. The efforts to grow its selenite sibling resulted in mixed halide compound, Fe(Te₁.₅Se₀.₅)O₅Cl, which was found crystallizing in a new structural type and possessing properties drastically different from those of a parent system. Hereby we report the studies of magnetization M and specific heat Cₚ, combined with Raman spectroscopy and density functional theory calculations in Fe(Te₁.₅Se₀.₅)O₅Cl. Its magnetic subsystem features weakly coupled Fe³⁺ - Fe³⁺ dimers showing the regime of short-range correlations at TM ~ 70 K and long-range order at TN = 22 K. In a magnetically ordered state, sizable spin-orbital interactions lead to a small canting of Fe³⁺ moments. The density functional theory calculations of leading exchange interactions were found in agreement with measurements of thermodynamic properties and Raman spectroscopy. Besides, because of the relatively large magnetic moment of the Fe³⁺ ion, we found that magnetic dipole-dipole interactions contribute significantly to experimentally observed orientation of magnetization easy axis in ac-plane. As a conclusion, we suggest a model of magnetic subsystem in magnetically ordered state of Fe(Te₁.₅Se₀.₅)O₅Cl based on a model of interacting dimers.

Keywords: dipole-dipole interactions, low dimensional magnetism, selenite, spin canting

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Authors: Muhammad Zaman, Guohua Fang, Muhammad Saifullah,

Abstract:

The presented study emphasize at an optimal model to compare past and future optimal hydropower generation. In order to get maximum benefits from the Xin’anjiang hydropower station a model is developed. A Particle Swarm Optimization (PSO) has purposed and past and future water flow is used to get the maximum benefits from future water resources in this study. The results revealed that the future hydropower generation is more than the past generation. This paper gives us idea that what could we get in the past using optimal method of electricity generation and what can we get in the future using this technique.

Keywords: PSO, future water resources, optimization, Xin’anjiang,

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Authors: Sirapat Lookrak, Anol Paisal

Abstract:

Space debris has numerous manifestations, including ferro-metalize and non-ferrous. The electric field will induce negative charges to split from positive charges inside the space debris. In this research, we focus only on conducting materials. The assumption is that the electric charge density of a conducting surface is proportional to the electric field on that surface due to Gauss's Law. We are trying to find the induced charge density from an external electric field perpendicular to a conducting spherical surface. An object is a sphere on which the external electric field is not uniform. The electric field is, therefore, considered locally. The localised spherical surface is a tangent plane, so the Gaussian surface is a very small cylinder, and every point on a spherical surface has its own cylinder. The electric field from a circular electrode has been calculated in near-field and far-field approximation and shown Explanation Touchless maneuvering space debris orbit properties. The electric charge density calculation from a near-field and far-field approximation is done.

Keywords: near-field approximation, far-field approximation, localized Gauss’s law, electric charge density

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Authors: Yi Zhang, Yuan Tian, Jiehua Chen, Sihong Gu

Abstract:

Chip-scale spin-exchange relaxation free (SERF) atomic magnetometer makes use of millimeter-scale vapor cells micro-fabricated by Micro-electromechanical Systems (MEMS) technique and SERF mechanism, resulting in the characteristics of high spatial resolution and high sensitivity. It is useful for biomagnetic imaging including magnetoencephalography and magnetocardiography. In a prevailing scheme, circularly polarized on-resonance laser beam is adapted for both pumping and probing the atomic polarization. And the magnetic-field-sensitive signal is extracted by transmission laser intensity enhancement as a result of atomic polarization increase on zero field level crossing resonance. The scheme is very suitable for integration, however, the laser amplitude modulation (AM) noise and laser frequency modulation to amplitude modulation (FM-AM) noise is superimposed on the photon shot noise reducing the signal to noise ratio (SNR). To suppress AM and FM-AM noise the paper puts forward a novel scheme which adopts circularly polarized on-resonance light pumping and linearly polarized frequency-detuning laser probing. The transmission beam is divided into transmission and reflection beams by a polarization analyzer, the angle between the analyzer's transmission polarization axis and frequency-detuning laser polarization direction is set to 45°. The magnetic-field-sensitive signal is extracted by polarization rotation enhancement of frequency-detuning laser which induces two beams intensity difference increase as the atomic polarization increases. Therefore, AM and FM-AM noise in two beams are common-mode and can be almost entirely canceled by differential detection. We have carried out an experiment to study our scheme. The experiment reveals that the noise in the differential signal is obviously smaller than that in each beam. The scheme is promising to be applied for developing more sensitive chip-scale magnetometer.

Keywords: atomic magnetometer, chip scale, differential detection, spin-exchange relaxation free

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Authors: Louvill Manangan Ozarraga

Abstract:

this study was designed to ascertain the concept of revenue generation system of Bacolod, Lanao del Norte, through the completely enumerated elected officials and permanent employees sample respondents. The pertinent data were obtained through the use of structured questionnaire and with the help of key informants. The study utilized a cross-sectional survey design to analyze and interpret the data using frequency count, percentage distribution, and weighted mean. For the major findings, the local revenue generation of the Municipality has increased by Php 4,465,394.21 roughly 73.52% from years 2018 to 2020. Administrative activities help the Municipality cope up with development namely, issuance of ordinance, personnel augmentation and collection strategies. Moreover, respondents were undecided whether revenue generation contributed to infrastructures and purchases of assets. Majority of the respondents agreed that the municipality’s local revenue generation contributes to the social welfare of its constituents. Also, the respondents disagreed that locally generated revenue augments the 20% development fund. The study revealed that there is a big difference on the 2018 and 2020 Real Property Tax (RPT) collection. No committee was created to monitor and supervise the municipal revenue generation system. The Municipality, through partnership with TESDA, provides skilled-job opportunity to its constituents and participants.

Keywords: contribution, development, Bacolod Lanao del Norte, revenue generation system

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Authors: Taufik Mulyadin

Abstract:

The tuition reform for public colleges that the Indonesian government initiated and has implemented since 2013 resulted in the growing number of college students from low-income families, many of whose parents did not attend college. This study sought to examine the experiences of persistence for Indonesian first-generation college students in public universities utilizing social capital as a framework. It is a qualitative study with a phenomenological approach primarily to capture the essence of how Indonesian first-generation college students interpret, process, and experience their persistence during college years. Fifteen Indonesian young college graduates were involved as well as questionnaire and interview were employed for data collection in this study. It revealed certain themes from the experiences that first-generation college students attributed to their persistence: (a) family encouragement, (b) support from friends, (c) guidance from faculty and staff, (d) fund of knowledge they bring with them, (e) financial aid availability, and (f) self-motivation. By examining first-generation college students’ voices, Indonesian public universities can better support, engage, and retain this group of students who were historically struggled to persist in college and complete their degree.

Keywords: first-generation student, Indonesian higher education, persistence, public universities

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Authors: M. Ibrahim Ali, M. El Dawi, M. A. Mohamed Ali

Abstract:

In this study, the use of magnetic gradient survey, and the geoelectrical ground methods used together to explore archaeological features in Nuri’s pyramids area. Research methods used and the procedures and methodologies have taken full right during the study. The magnetic survey method was used to search for archaeological features using (Geoscan Fluxgate Gradiometer (FM36)). The study area was divided into a number of squares (networks) exactly equal (20 * 20 meters). These squares were collected at the end of the study to give a major network for each region. Networks also divided to take the sample using nets typically equal to (0.25 * 0.50 meter), in order to give a more specific archaeological features with some small bipolar anomalies that caused by buildings built from fired bricks. This definition is important to monitor many of the archaeological features such as rooms and others. This main network gives us an integrated map displayed for easy presentation, and it also allows for all the operations required using (Geoscan Geoplot software). The parallel traverse is the main way to take readings of the magnetic survey, to get out the high-quality data. The study area is very rich in old buildings that vary from small to very large. According to the proportion of the sand dunes and the loose soil, most of these buildings are not visible from the surface. Because of the proportion of the sandy dry soil, there is no connection between the ground surface and the electrodes. We tried to get electrical readings by adding salty water to the soil, but, unfortunately, we failed to confirm the magnetic readings with electrical readings as previously planned.

Keywords: archaeological features, independent grids, magnetic gradient, Nuri pyramid

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