Search results for: signature dependence

Authors: B. A. Behrens, H. J. Maier, A. Neumann, J. Moritz, S. Hübner, T. Gretzki, F. Nürnberger, A. Spiekermeier

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Press-hardened profiles are used e.g. for automotive applications in order to improve light weight construction due to the high reachable strength. The application of interior water-air spray cooling contributes to significantly reducing the cycle time in the production of heat-treated tubes. This paper describes a new manufacturing method for producing press-hardened hollow profiles by means of an additional interior cooling based on a water-air spray. Furthermore, this paper provides the results of thorough investigations on the properties of press-hardened tubes in dependence of varying spray parameters.

Keywords: 22MnB5, press hardening, water-air spray cooling, hollow profiles, tubes

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Authors: Yisau Adelaja Odusote, Olakanmi Felix Akinto

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The associative tendency between like atoms in molten Cd-Ga and Cd-In alloy systems has been studied by using the Quasi-Chemical Approximation Model (QCAM). The concentration dependence of the microscopic functions (the concentration-concentration fluctuations in the long-wavelength limits, Scc(0), the chemical short-range order (CSRO) parameter α1 as well as the chemical diffusion) and the mixing properties as the free energy of mixing, GM, enthalpy of mixing and entropy of mixing of the two molten alloys have been determined. Thermodynamic properties of both systems deviate positively from Raoult's law, while the systems are characterized by positive interaction energy. The role of atomic size ratio on the alloying properties was discussed.

Keywords: homo-pairs, interchange energy, enthalpy, entropy, Cd-Ga, Cd-In

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Authors: Keiji Komatsu, Hayato Maruyama, Ariyuki Kato, Atsushi Nakamura, Shigeo Ohshio, Hiroki Akasaka, Hidetoshi Saitoh

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Violet Sr–Al–O:Eu2+ phosphor particles were synthesized from a metal–ethylenediaminetetraacetic acid (EDTA) solution of Sr, Al, Eu, and particulate alumina via spray drying and sintering in a reducing atmosphere. The crystal structures and emission properties at 85–300 K were investigated. The composition of the violet Sr–Al–O:Eu2+ phosphor particles was determined from various Sr–Al–O:Eu2+ phosphors by their emission properties’ dependence on temperature. The highly crystalline SrAl12O19:Eu2+ emission phases were confirmed by their crystallite sizes and the activation energies for the 4f5d–8S7/2 transition of the Eu2+ ion. These results showed that the material identification for the violet Sr–Al–O:Eu2+ phosphor was accomplished by the low-temperature luminescence measurements.

Keywords: low temperature luminescence spectroscopy, material identification, strontium aluminates phosphor, emission properties

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Authors: Sajjad Yahaghifar

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From the end of the last century, the importance and use of renewable energy sources have gained prominence, due not only by the fossil fuels dependence reduction, but mainly by environmental reasons related to climate change and the effects to the humanity. Consequently, solar energy has been arousing interest in several countries for being a technology considered clean, with reduced environmental impact. The output power of photo voltaic (PV) arrays is always changing with weather conditions,i.e., solar irradiation and atmospheric temperature. Therefore, maximum power point tracking (MPPT) control to extract maximum power from the PV arrays at real time becomes indispensable in PV generation system. This paper Study MPPT and total harmonic distortion (THD) in the city of Tabriz, Iran with the grid-connected PV system as distributed generation.

Keywords: MPPT, THD, grid-connected, PV system

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Authors: M. Yaqub Khan, Usman Shabbir

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History of plasma reveals that continuous struggle of experimentalists and theorists are not fruitful for confinement up to now. It needs a change to bring the research through entropy. Approximately, all the quantities like number density, temperature, electrostatic potential, etc. are connected to entropy. Therefore, it is better to change the way of research. In ion temperature gradient mode with the help of Braginskii model, Boltzmannian electrons, effect of velocity shear is studied inculcating entropy in the magnetoplasma. New dispersion relation is derived for ion temperature gradient mode, and dependence on entropy gradient drift is seen. It is also seen velocity shear enhances the instability but in anomalous transport, its role is not seen significantly but entropy. This work will be helpful to the next step of tokamak and space plasmas.

Keywords: entropy, velocity shear, ion temperature gradient mode, drift

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Authors: Emad A. Jaffar Al-Mulla

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In this study, a biopolymer-based nanocomposite was successfully prepared through melt blending technique. Two biodegradable polymers, polycaprolactone and starch, environmental friendly and obtained from renewable, easily available raw materials, have been chosen. Fatty hydrazide, synthesized from palm oil, has been used as a surfactant to modify montmorillonite (natural clay) for preparation of polycaprolactone/starch nanocomposite. X-ray diffraction and transmission electron microscopy were used to characterize nanocomposite formation. Compatibility of the blend was improved by adding 3% weight modified clay. Higher biodegradability and thermal stability of nanocomopeite were also observed compared to those of the polycaprolactone/starch blend. This product will solve the problem of plastic waste, especially disposable packaging, and reduce the dependence on petroleum-based polymers and surfactants.

Keywords: polycaprolactone, starch, biodegradable, nanocomposite

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Authors: S. K. Appiah, E. N. Aidoo, D. Asamoah Owusu, M. W. Nuonabuor

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Urbanization remains one of the unique predominant factors which is linked to the destruction of urban environment and its associated cases of soil contamination by heavy metals through the natural and anthropogenic activities. These activities are important sources of toxic heavy metals such as arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), and lead (Pb), nickel (Ni) and zinc (Zn). Often, these heavy metals lead to increased levels in some areas due to the impact of atmospheric deposition caused by their proximity to industrial plants or the indiscriminately burning of substances. Information gathered on potentially hazardous levels of these heavy metals in soils leads to establish serious health and urban agriculture implications. However, characterization of spatial variations of soil contamination by heavy metals in Ghana is limited. Kumasi is a Metropolitan city in Ghana, West Africa and is challenged with the recent spate of deteriorating soil quality due to rapid economic development and other human activities such as “Galamsey”, illegal mining operations within the metropolis. The paper seeks to use both univariate and multivariate geostatistical techniques to assess the spatial distribution of heavy metals in soils and the potential risk associated with ingestion of sources of soil contamination in the Metropolis. Geostatistical tools have the ability to detect changes in correlation structure and how a good knowledge of the study area can help to explain the different scales of variation detected. To achieve this task, point referenced data on heavy metals measured from topsoil samples in a previous study, were collected at various locations. Linear models of regionalisation and coregionalisation were fitted to all experimental semivariograms to describe the spatial dependence between the topsoil heavy metals at different spatial scales, which led to ordinary kriging and cokriging at unsampled locations and production of risk maps of soil contamination by these heavy metals. Results obtained from both the univariate and multivariate semivariogram models showed strong spatial dependence with range of autocorrelations ranging from 100 to 300 meters. The risk maps produced show strong spatial heterogeneity for almost all the soil heavy metals with extremely risk of contamination found close to areas with commercial and industrial activities. Hence, ongoing pollution interventions should be geared towards these highly risk areas for efficient management of soil contamination to avert further pollution in the metropolis.

Keywords: coregionalization, heavy metals, multivariate geostatistical analysis, soil contamination, spatial distribution

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Authors: Rose Antony, Vivekanand B. Khanapuri, Karuna Jain

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Online groceries have transformed the way the supply chains are managed. These are facing numerous challenges in terms of product wastages, low margins, long breakeven to achieve and low market penetration to mention a few. The e-grocery chains need to overcome these challenges in order to survive the competition. The purpose of this paper is to carry out a structural analysis of the enablers in e-grocery chains by applying Interpretive Structural Modeling (ISM) and MICMAC analysis in the Indian context. The research design is descriptive-explanatory in nature. The enablers have been identified from the literature and through semi-structured interviews conducted among the managers having relevant experience in e-grocery supply chains. The experts have been contacted through professional/social networks by adopting a purposive snowball sampling technique. The interviews have been transcribed, and manual coding is carried using open and axial coding method. The key enablers are categorized into themes, and the contextual relationship between these and the performance measures is sought from the Industry veterans. Using ISM, the hierarchical model of the enablers is developed and MICMAC analysis identifies the driver and dependence powers. Based on the driver-dependence power the enablers are categorized into four clusters namely independent, autonomous, dependent and linkage. The analysis found that information technology (IT) and manpower training acts as key enablers towards reducing the lead time and enhancing the online service quality. Many of the enablers fall under the linkage cluster viz., frequent software updating, branding, the number of delivery boys, order processing, benchmarking, product freshness and customized applications for different stakeholders, depicting these as critical in online food/grocery supply chains. Considering the perishability nature of the product being handled, the impact of the enablers on the product quality is also identified. Hence, study aids as a tool to identify and prioritize the vital enablers in the e-grocery supply chain. The work is perhaps unique, which identifies the complex relationships among the supply chain enablers in fresh food for e-groceries and linking them to the performance measures. It contributes to the knowledge of supply chain management in general and e-retailing in particular. The approach focus on the fresh food supply chains in the Indian context and hence will be applicable in developing economies context, where supply chains are evolving.

Keywords: interpretive structural modelling (ISM), India, online grocery, retail operations, supply chain management

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Authors: Jesse Silas Mshelia, Michael Mamman Degri, Akeweta Emmanuel Samaila

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This review was conducted in the North-Eastern part of Nigeria where there are a lot of challenges of poverty and low level of productivity of farmlands as a result of dwindling soil fertility and dependence on crops that are not so much adopted to the soil and climatic condition and the prevailing farming systems of the area which is predominantly mixed cropping. The crops that are neglected are well fitted into this system of production and yield better with the low level of input and management and give a higher profit margin. These crops, the farmers have mastered the production techniques, but do not have the scientific knowledge to improve the quality of the seed and the products hence need the intervention of modern technologies to benefit maximally from the full potentials of these crops.

Keywords: farming systems, neglected crops, potentials, underutilised

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Authors: Ossama Al-Maliki

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Europay, MasterCard, and Visa (EMV) is one of the most popular payment protocol in the world. The EMV protocol supports Chip and PIN Transactions, Chip and Signature transactions, and Contactless transactions. This protocol suffers from tens of £ millions of lost per year due to many fraudulent payments. This is due to several reported vulnerable points in the protocols used for such payments that allow skimming, replay, cloning, Mole Point of Sale (POS), relay, and other attacks to be conducted. In this paper, we are focusing on the EMV contactless specification and we have proposed two proposal solutions to the addition of a localization factor to enhance the payment authentication of such transactions designed to prevent relay, cloning, and Mole-POS attacks. Our proposed solution is a back-end localization scheme to help the Issuer-Bank compare the location of the genuine cardholder in relation to the used POS. Our scheme uses 'something you have' which is the Cardholder Smartphone (CSP) to provide the location of the cardholder at the time of the transaction and without impacting the contactless payment time/protocol. The Issuer-bank obtain the CSP Location using tried and tested localization techniques, and independently of the cardholder. Both of our proposal solutions do not require infrastructure changes, and it uses existing EMV/SP protocol messages to communicate our scheme information.

Keywords: NFC, RFID, contactless card, authentication, location, EMV

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Authors: Kiurski S. Jelena, Kecić S. Vesna, Oros B. Ivana, Ranogajec G. Jonjaua

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The paper represents the dependence of ammonia concentration on microclimate parameters and photocopying shop circulation. The concentration of ammonia was determined during 8-hours working time over five days including three sampling points of a photocopying shop in Novi Sad, Serbia. The obtained results pointed out that the room temperature possesses the highest impact on ammonia release. The obtained ammonia concentration was in the range of 1.53 to 0.42ppm and decreased with the temperature decreasing from 24.6 to 20.7 °C. As the detected concentrations were within the permissible levels of The Occupational Safety and Health Administration, The National Institute for Occupational Safety and The Health and Official Gazette of Republic of Serbia, in the range of 35 to 200ppm, there was no danger to the employee’s health in the photocopying shop.

Keywords: ammonia, emission, indoor environment, photocopying procedure

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Authors: R. H. Bari

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The nanostructured thin films of CdSnO3 are sensitive to change in their environment. CdSnO3 is successfully used as gas sensor due to the dependence of the electrical conductivity on the ambient gas composition. Nanostructured CdSnO3 thin films of different substrate temperature (300 0C, 350 0C, 400 0C and 450 0C) were deposited onto heated glass substrate by simple spray pyrolysis (SP) technique. Sensing elements of nanostructured CdSnO3 were annealed at 500 0C for 1 hrs. Characterization includes a different analytical technique such as, X-ray diffractogram (XRD), energy dispersive X-ray analysis (EDAX), and Field emission scanning electron microscope (FE-SEM). The average grain size observed from XRD and FF-SEM was found to be less than 18.36 and 23 nm respectively. The films sprayed at substrate temperature for 400 0C was observed to be most sensitive (S = 530) to SO2 for 500 ppm at 300 0C. The response and recovery time is 4 sec, 8 sec respectively.

Keywords: nanostructured CdSnO3, spray pyrolysis, SO2 gas sensing, quick response

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Authors: S. Abou El-Azm, U. Kruchonak, M. Gostkin, A. Guskov, A. Zhemchugov

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Semiconductor detectors are widely used in nuclear physics and high-energy physics experiments. The application of semiconductor detectors could be limited by their ultimate radiation resistance. The increase of radiation defects concentration leads to significant degradation of the working parameters of semiconductor detectors. The investigation of radiation defects properties in order to enhance the radiation hardness of semiconductor detectors is an important task for the successful implementation of a number of nuclear physics experiments; we presented some information about radiation hardness materials like diamond, sapphire and CdTe. Also, the results of measurements I-V characteristics, charge collection efficiency and its dependence on the bias voltage for different doses of high resistivity (GaAs: Cr) and Si at LINAC-200 accelerator and reactor IBR-2 are presented.

Keywords: semiconductor detectors, radiation hardness, GaAs, Si, CCE, I-V, C-V

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Authors: J. Zach, J. Hroudova, J. Brozovsky

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Thermal insulation materials based on natural fibers represent a very promising area of materials based on natural easy renewable row sources. These materials may be in terms of the properties of most competing synthetic insulations, but show somewhat higher moisture sensitivity and thermal insulation properties are strongly influenced by the density and orientation of fibers. The paper described the problem of hygrothermal behavior of thermal insulation materials based on natural plant and animal fibers. This is especially the dependence of the thermal properties of these materials on the type of fiber, bulk density, temperature, moisture and the fiber orientation.

Keywords: thermal insulating materials, hemp fibers, sheep wool fibers, thermal conductivity, moisture

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Authors: Kwedi L. M. Nsah, Hisao Uchiki

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Quantum computation is a new and exciting field making use of quantum mechanical phenomena. In classical computers, information is represented as bits, with values either 0 or 1, but a quantum computer uses quantum bits in an arbitrary superposition of 0 and 1, enabling it to reach beyond the limits predicted by classical information theory. lanthanide ion quantum computer is an organic crystal, having a lanthanide ion. Europium is a favored lanthanide, since it exhibits nuclear spin coherence times, and Eu(III) is photo-stable and has two stable isotopes. In a europium organic crystal, the key factor is the mutual dipole-dipole interaction between two europium atoms. Crystals of the complex were formed by making a 2 :1 reaction of Eu(fod)3 and bpm. The transparent white crystals formed showed brilliant red luminescence with a 405 nm laser. The photoluminescence spectroscopy was observed both at room and cryogenic temperatures (300-14 K). The luminescence spectrum of [Eu(fod)3(μ-bpm) Eu(fod)3] showed characteristic of Eu(III) emission transitions in the range 570–630 nm, due to the deactivation of 5D0 emissive state to 7Fj. For the application of dinuclear Eu3+ complex to q-bit device, attention was focused on 5D0 -7F0 transition, around 580 nm. The presence of 5D0 -7F0 transition at room temperature revealed that at least one europium symmetry had no inversion center. Since the line was unsplit by the crystal field effect, any multiplicity observed was due to a multiplicity of Eu3+ sites. For q-bit element, more narrow line width of 5D0 → 7F0 PL band in Eu3+ ion was preferable. Cryogenic temperatures (300 K – 14 K) was applicable to reduce inhomogeneous broadening and distinguish between ions. A CCD image sensor was used for low temperature Photoluminescence measurement, and a far better resolved luminescent spectrum was gotten by cooling the complex at 14 K. A red shift by 15 cm-1 in the 5D0 - 7F0 peak position was observed upon cooling, the line shifted towards lower wavenumber. An emission spectrum at the 5D0 - 7F0 transition region was obtained to verify the line width. At this temperature, a peak with magnitude three times that at room temperature was observed. The temperature change of the 5D0 state of Eu(fod)3(μ-bpm)Eu(fod)3 showed a strong dependence in the vicinity of 60 K to 100 K. Thermal quenching was observed at higher temperatures than 100 K, at which point it began to decrease slowly with increasing temperature. The temperature quenching effect of Eu3+ with increase temperature was caused by energy migration. 100 K was the appropriate temperature for the observation of the 5D0 - 7F0 emission peak. Europium dinuclear complex bridged by bpm was successfully prepared and monitored at cryogenic temperatures. At 100 K the Eu3+-dope complex has a good thermal stability and this temperature is appropriate for the observation of the 5D0 - 7F0 emission peak. Sintering the sample above 600o C could also be a method to consider but the Eu3+ ion can be reduced to Eu2+, reasons why cryogenic temperature measurement is preferably over other methods.

Keywords: Eu(fod)₃, europium dinuclear complex, europium ion, quantum bit, quantum computer, 2, 2-bipyrimidine

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Authors: Tomotaka Aoki, Isao Tomita

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We examined the on-off ratio and frequency components of output signals from an electron-interference device made of GaAs/AlₓGa₁₋ₓAs by solving the time-dependent Schrödinger's equation on conducting electrons in the channel waveguide of the device. For electron-wave modulation, a periodic voltage of frequency f was applied to the channel. Furthermore, we examined the voltage-amplitude dependence of the signals in time and frequency domains and found that large applied voltage deformed the output-signal waveform and created additional side modes (frequencies) near the modulation frequency f and that there was a trade-off between on-off ratio and side-mode creation.

Keywords: electrical conduction, electron interference, frequency spectrum, on-off ratio

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Authors: Mehtap Dursun, Zeynep Şener

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Supplier selection is considered as one of the most critical issues encountered by operations and purchasing managers to sharpen the company’s competitive advantage. In this paper, a novel fuzzy multi-criteria group decision making approach integrating quality function deployment (QFD) and decision making trial and evaluation laboratory (DEMATEL) method is proposed for supplier selection. The proposed methodology enables to consider the impacts of inner dependence among supplier assessment criteria. A house of quality (HOQ) which translates purchased product features into supplier assessment criteria is built using the weights obtained by DEMATEL approach to determine the desired levels of supplier assessment criteria. Supplier alternatives are ranked by a distance-based method.

Keywords: DEMATEL, group decision making, QFD, supplier selection

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Authors: Doreen Mekunda

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This paper is built on the premise that the current socio-political crisis in the two restive regions of Cameroon, though enveloped with destructive and devastating trends (effects) on both property and human lives, is not without its strengths and merits. It is incontestable that many cultures, to a greater extent, are going to be destroyed as people forcibly move from war-stricken habitats to non-violent places. Many cultural potentials, traditional shrines, artifacts, art, and crafts, etc., are unknowingly or knowingly disfigured, and many other ugly things will, by the end of the crisis, affect the cultures of these two regions under siege and of the receiving population. A plethora of other problems like the persecution of Internally Displaced Persons (IDPs) for being displaced and blamed for increased crime rates and the existence of cultural and ethnic differences that produce both inter-tribal and interpersonal conflicts and conflicts between communities will abound. However, there is the emergence of rapid literature, and other forms of cultural productions, whether written or oral, is visible, thereby precipitating a rich cultural diversity due to the coming together of a variety of cultures of both the IDPs and the receiving populations, rapid urbanization, improvement of health-related issues, the rebirth of indigenous cultural practices, the development of social and lingua-cultural competences, dependence on alternative religions, faith and spirituality. Even financial and economic dependence, though a burden to others by IDPs, has its own merits as it improves the living standards of the IDPs. To be able to obtain plausible results, cultural materialism, which is a literary theory that hinges on the empirical study of socio-cultural systems within a materialist infrastructure-super-structure framework, is employed together with the postcolonial theory. Postcolonial theory because the study deals with postcolonial experiences/tenets of migration, hybridity, ethnicity, indignity, language, double consciousness, migration, center/margin binaries, and identity, amongst others. The study reveals that the involuntary movement of persons from their habitual homes brings about movement in cultures, thus, the emergence of new cultures. The movement of people who hold fast to their cultural heritage can only influence new forms of literature, the development of new communication competences, the rise of alternative religion, faith and spirituality, the re-emergence of customary and traditional legal systems that might have been abandoned for the new judicial systems, and above all the revitalization of traditional health care systems.

Keywords: alternative religion, emergence, socio-political crisis, spirituality, lingua-cultural competences

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Authors: Aleksandr I. Korobov, Natalia V. Shirgina, Aleksey I. Kokshaiskiy

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The transformation of two types of acoustic waves can occur on a flat interface between two solids at oblique incidence of longitudinal and shear bulk acoustic waves (BAW). This paper presents the results of experimental studies of the properties of reflection and propagation of longitudinal wave and generation of second and third longitudinal and shear harmonics of BAW at oblique incidence of longitudinal BAW on a flat rough boundary between two solids. The experimental sample was a rectangular isosceles pyramid made of D16 aluminum alloy with the plane parallel bases cylinder made of D16 aluminum alloy pressed to the base. The piezoelectric lithium niobate transducer with a resonance frequency of 5 MHz was secured to one face of the pyramid to generate a longitudinal wave. Longitudinal waves emitted by this transducer felt at an angle of 45° to the interface between two solids and reflected at the same angle. On the opposite face of the pyramid, and on the flat side of the cylinder was attached longitudinal transducer with resonance frequency of 10 MHz or the shear transducer with resonance frequency of 15 MHz. These transducers also effectively received signal at a frequency of 5 MHz. In the spectrum of the transmitted and reflected BAW was observed shear and longitudinal waves at a frequency of 5 MHz, as well as longitudinal harmonic at a frequency harmonic of 10 MHz and a shear harmonic at frequency of 15 MHz. The effect of reversing changing of external pressure applied to the rough interface between two solids on the value of the first and higher harmonics of the BAW at oblique incidence on the interface of the longitudinal BAW was experimentally investigated. In the spectrum of the reflected signal from the interface, there was a decrease of amplitudes of the first harmonics of the signal, and non-monotonic dependence of the second and third harmonics of shear wave with an increase of the static pressure applied to the interface. In the spectrum of the transmitted signal growth of the first longitudinal and shear harmonic amplitude and non-monotonic dependence - first increase and then decrease in the amplitude of the second and third longitudinal shear harmonic with increasing external static pressure was observed. These dependencies were hysteresis at reversing changing of external pressure. When pressure applied to the border increased, acoustic contact between the surfaces improves. This increases the energy of the transmitted elastic wave and decreases the energy of the reflected wave. The second longitudinal acoustic harmonics generation was associated with the Hertz nonlinearity on the interface of two pressed rough surfaces, the generation of the third harmonic was caused by shear hysteresis nonlinearity due to dry friction on a rough interface. This study was supported by the Russian Science Foundation (project №14-22-00042).

Keywords: generation of acoustic harmonics, hysteresis nonlinearity, Hertz nonlinearity, transformation of acoustic waves

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Authors: Ghazi Faisal Najmuldeen, Rosli Mohd Yunus, Nurfarahin Bt Harun, Mardhiana Binti Ismail

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The microwave extraction has attracted great interest among the researchers. The main virtue of the microwave technique is cost-effective, time saving and simple handling procedure. Castor beans was chosen because of its high content in fatty acid, especially ricinoleic acid. The purpose of this research is to extract the castor oil by using the microwave assisted extraction (MAE) using ethanol as solvent and to investigate the influence of extraction time on castor oil yield and to characterize the main composition of the produced castor oil by using the GC-MS. It was found that there is a direct dependence between the oil yield and the time of extraction as it increases from 45% to 58% as the time increase from 10 min to 60 min. The major components of castor oil detected by GC-MS were ricinoleic acid, linoleic acid and oleic acid.

Keywords: microwave assisted extraction (MAE), castor oil, ricinoleic acid, linoleic acid

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Authors: Syahidah N. Zulkifli, Herlina A. Rahim, Nurul A. M. Subha

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Sustaining water quality is critical in order to avoid any harmful health consequences for end-user consumers. The detection of microbial impurities at the household level is the foundation of water security. Water quality is now monitored only at water utilities or infrastructure, such as water treatment facilities or reservoirs. This research provides a first-hand scientific understanding of microbial composition presence in Malaysia’s household point-of-use (POUs) water supply influenced by seasonal fluctuations, standstill periods, and flow dynamics by using the NIR-Raman spectroscopic technique. According to the findings, 20% of water samples were contaminated by pathogenic bacteria, which are Legionella and Salmonella cells. A comparison of the spectra reveals significant signature peaks (420 cm⁻¹ to 1800 cm⁻¹), including species-specific bands. This demonstrates the importance of regularly monitoring POUs water quality to provide a safe and clean water supply to homeowners. Conventional Raman spectroscopy, up-to-date, is no longer suited for real-time monitoring. Therefore, this study introduced an alternative micro-spectrometer to give a rapid and sustainable way of monitoring POUs water quality. Assessing microbiological threats in water supply becomes more reliable and efficient by leveraging IoT protocol.

Keywords: microbial contaminants, water quality, water monitoring, Raman spectroscopy

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Authors: Jacob Schwartz, Maxim Durach, Aniruddha Mitra, Abbas Rashidi, Glen Sage, Atin Adhikari

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NIOSH (National Institute for Occupational Safety and Health) approved N95 respirators are commonly used by workers in construction sites where there is a large amount of dust being produced from sawing, grinding, blasting, welding, etc., both electrostatically charged and not. A significant portion of airborne particles in construction sites could be nanoparticles created beside coarse particles. The penetration of the particles through the masks may differ depending on the size and charge of the individual particle. In field experiments relevant to this current study, we found that nanoparticles of medium size ranges are penetrating more frequently than nanoparticles of smaller and larger sizes. For example, penetration percentages of nanoparticles of 11.5 – 27.4 nm into a sealed N95 respirator on a manikin head ranged from 0.59 to 6.59%, whereas nanoparticles of 36.5 – 86.6 nm ranged from 7.34 to 16.04%. The possible causes behind this increased penetration of mid-size nanoparticles through mask filters are not yet explored. The objective of this study is to identify causes behind this unusual behavior of mid-size nanoparticles. We have considered such physical factors as Boltzmann distribution of the particles in thermal equilibrium with the air, kinetic energy of the particles at impact on the mask, Stoke’s drag force, and electrostatic forces in the mask stopping the particles. When the particles collide with the mask, only the particles that have enough kinetic energy to overcome the energy loss due to the electrostatic forces and the Stokes’ drag in the mask can pass through the mask. To understand this process, the following assumptions were made: (1) the effect of Stoke’s drag depends on the particles’ velocity at entry into the mask; (2) the electrostatic force is proportional to the charge on the particles, which in turn is proportional to the surface area of the particles; (3) the general dependence on electrostatic charge and thickness means that for stronger electrostatic resistance in the masks and thicker the masks’ fiber layers the penetration of particles is reduced, which is a sensible conclusion. In sampling situations where one mask was soaked in alcohol eliminating electrostatic interaction the penetration was much larger in the mid-range than the same mask with electrostatic interaction. The smaller nanoparticles showed almost zero penetration most likely because of the small kinetic energy, while the larger sized nanoparticles showed almost negligible penetration most likely due to the interaction of the particle with its own drag force. If there is no electrostatic force the fraction for larger particles grows. But if the electrostatic force is added the fraction for larger particles goes down, so diminished penetration for larger particles should be due to increased electrostatic repulsion, may be due to increased surface area and therefore larger charge on average. We have also explored the effect of ambient temperature on nanoparticle penetrations and determined that the dependence of the penetration of particles on the temperature is weak in the range of temperatures in the measurements 37-42°C, since the factor changes in the range from 3.17 10-3K-1 to 3.22 10-3K-1.

Keywords: respiratory protection, industrial hygiene, aerosol, electrostatic force

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Authors: Tauqir A. Moughal, Fusheng Yu, Abeer Mazher

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Land-cover and land-use change information are important because of their practical uses in various applications, including deforestation, damage assessment, disasters monitoring, urban expansion, planning, and land management. Therefore, developing change detection methods for remote sensing images is an important ongoing research agenda. However, detection of change through optical remote sensing images is not a trivial task due to many factors including the vagueness between the boundaries of changed and unchanged regions and spatial dependence of the pixels to its neighborhood. In this paper, we propose a binary change detection technique for bi-temporal optical remote sensing images. As in most of the optical remote sensing images, the transition between the two clusters (change and no change) is overlapping and the existing methods are incapable of providing the accurate cluster boundaries. In this regard, a methodology has been proposed which uses the fuzzy c-means clustering to tackle the problem of vagueness in the changed and unchanged class by formulating the soft boundaries between them. Furthermore, in order to exploit the neighborhood information of the pixels, the input patterns are generated corresponding to each pixel from bi-temporal images using 3×3, 5×5 and 7×7 window. The between images and within image spatial dependence of the pixels to its neighborhood is quantified by using Pearson product moment correlation and Moran’s I statistics, respectively. The proposed technique consists of two phases. At first, between images and within image spatial correlation is calculated to utilize the information that the pixels at different locations may not be independent. Second, fuzzy c-means technique is used to produce two clusters from input feature by not only taking care of vagueness between the changed and unchanged class but also by exploiting the spatial correlation of the pixels. To show the effectiveness of the proposed technique, experiments are conducted on multispectral and bi-temporal remote sensing images. A subset (2100×1212 pixels) of a pan-sharpened, bi-temporal Landsat 5 thematic mapper optical image of Los Angeles, California, is used in this study which shows a long period of the forest fire continued from July until October 2009. Early forest fire and later forest fire optical remote sensing images were acquired on July 5, 2009 and October 25, 2009, respectively. The proposed technique is used to detect the fire (which causes change on earth’s surface) and compared with the existing K-means clustering technique. Experimental results showed that proposed technique performs better than the already existing technique. The proposed technique can be easily extendable for optical hyperspectral images and is suitable for many practical applications.

Keywords: burned area, change detection, correlation, fuzzy clustering, optical remote sensing

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Authors: Sylwia Wiewiorowska, Zbigniew Muskalski

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The strain intensity and redundant strains, dependent in multistage TRIP wire drawing processes from values used single partial reductions, should influence on the intensity of transformation the retained austenite into martensite and thereby on mechanical properties of drawn wires. The numerical analysis of drawing processes with use of Drawing 2D programme, for steel wires made from TRIP steel with 0,29 % has been shown in the work. The change of strain intensity Ԑc and the values of redundant strain Ԑxy, has been determined for particular draws in dependence of used single partial reductions.

Keywords: steel wire, TRIP steel, drawing processes, fem modelling

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Authors: Bina Kumari, Subir K. Sarkar, Pradipta Bandyopadhyay

Abstract:

The autocorrelation function of the density fluctuation is studied in each of the two phases in a Gibbs Ensemble Monte Carlo (GEMC) simulation of the problem of phase separation for a square well potential with various values of its range. We find that the normalized autocorrelation function is described very well as a linear combination of an exponential function with a time scale τ₂ and a stretched exponential function with a time scale τ₁ and an exponent α. Dependence of (α, τ₁, τ₂) on the parameters of the GEMC algorithm and the range of the square well potential is investigated and interpreted. We also analyse the issue of how to choose the parameters of the GEMC simulation optimally.

Keywords: autocorrelation function, density fluctuation, GEMC, simulation

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Authors: Noureddine Benharkat, Abdelkader Chouaih, Nourdine Boukabcha

Abstract:

A thiourea derivative compound was synthesized and subjected to structural analysis using single-crystal X-ray diffraction (XRD). The crystallographic data unveiled its crystallization in the P21/c space group within the monoclinic system. Examination of the dihedral angles indicated a notable non-planar structure. To support and interpret these resulats, density functional theory (DFT) calculations were conducted utilizing the B3LYP functional along with a 6–311 G (d, p) basis set. Additionally, to assess the contribution of intermolecular interactions, Hirshfeld surface analysis and 2D fingerprint plots were employed. Various types of interactions, whether weak intramolecular or intermolecular, within a molecule can significantly impact its stability. The distinctive signature of non-covalent interactions can be detected solely through electron density analysis. The NCI-RDG analysis was employed to investigate both repulsive and attractive van der Waals interactions while also calculating the energies associated with intermolecular interactions and their characteristics. Additionally, a molecular docking study was studied to explain the structure-activity relationship, revealing that the title compound exhibited an affinity energy of -6.8 kcal/mol when docked with B-DNA (1BNA).

Keywords: computational chemistry, density functional theory, crystallography, molecular docking, molecular structure, powder x-ray diffraction, single crystal x-ray diffraction

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Authors: Y. R. Adullayev, О. О. Karimzada

Abstract:

Analytical expressions for inductances, current, ampere-turns, excitation winding, maximum width, coordinates of the levitation screen (LS) are derived for the calculation of electromagnetic devices based on tracking systems with levitation elements (TS with LS). Taking into account the expression of the complex magnetic resistance of the screen, the dependence of the screen width on the heating temperature of the physical and technical characteristics of the screen material and the relationship of the geometric dimensions of the magnetic circuit is established. Analytic expressions for a number of functional dependencies characterizing complex parameter relationships in explicit form are obtained and analyzed.

Keywords: tracking systems, levitation screens, electromagnetic levitation, excitation windings, magnetic cores, defining converter, receiving converter, electromagnetic force, electrical and magnetic resistance

Procedia PDF Downloads 218

Authors: Gabriel Chenevert, Abhilash Arora, Zeljko Pantic

Abstract:

The major problem underwater acoustic communication faces is the low data rate due to low signal frequency. By contrast, the Wi-Fi communication protocol offers high throughput but limited operating range due to the attenuation effect of the sea and ocean medium. However, short-range near-field underwater wireless power transfer systems offer an environment where Wi-Fi communication can be effectively integrated to collect data and deliver instructions to sensors in underwater sensor networks. In this paper, low-power, low-cost off-the-shelf Wi-Fi modules are explored experimentally for four selected parameters for different distances between units and water salinities. The results reveal a shorter operating range and stronger dependence on water salinity than reported so far for high-end Wi-Fi modules.

Keywords: Wi-Fi, wireless power transfer, underwater communications, ESP

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Authors: Sarah Abdourraziq, R. El Bachtiri

Abstract:

Renewable energies have a major importance of Morocco's new energy strategy. The geographical location of the Kingdom promotes the development of the use of solar energy. The use of this energy reduces the dependence on imports of primary energy, meets the growing demand for water and electricity in remote areas encourages the deployment of a local industry in the renewable energy sector and Minimize carbon emissions. Indeed, given the importance of the radiation intensity received and the duration of the sunshine, the country can cover some of its solar energy needs. The use of solar energy to pump water is one of the most promising application, this technique represents a solution wherever the grid does not exist. In this paper, we will present a presentation of photovoltaic pumping system components, and the important solar pumping projects installed in Morocco to supply water from remote area.

Keywords: PV pumping system, Morocco, PV panel, renewable energy

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Authors: Hajra Hussain

Abstract:

Positive education, the inclusion of social, emotional and intellectual skills across a curriculum, is fundamental to the optimal functioning of young people in any society because it combines the best teaching practices with the principles of positive psychology. While learning institutions foster academic skills, little attention is being paid to the identification and development of character strengths and their integration into teaching. There is an increasing recognition of the important role education plays in equipping today’s youth with 21st century social skills. For youth to succeed in this highly competitive environment, there is a need for positive education that is focused on character strengths such as the growth of social, emotional and intellectual skills that promote the flourishing of well-rounded individuals. Character strength programs and awareness are a necessity if the human capital within a region is to be competitive, productive and happy. The Counselling & Wellbeing Centre at Amity University Dubai has consistently implemented Character Strength awareness workshops and has found that such workshops have increased student life satisfaction due to individual awareness of signature strengths. A positive education/positive psychology framework with its key focus on the development of character strengths can be fundamental to individual's confidence and self-awareness; thus allowing both optimum flourishing and functioning.

Keywords: positive psychology, positive education, strengths, youth, happiness

Procedia PDF Downloads 254