Search results for: standard quantum limit

Authors: Bing–Jing Zhao, Chang-Kui Liu, Hong Wang, Min Hu

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Electron beam rapid manufacturing (EBRM) or Selective laser melting is an additive manufacturing process that uses 3D CAD data as a digital information source and energy in the form of a high-power laser beam or electron beam to create three-dimensional metal parts by fusing fine metallic powders together.Object:The present study was conducted to evaluate the mechanical properties ,the phase transformation,the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM,SLM and forging technique.Method: Ti-6Al-4V alloy standard test pieces were manufactured by EBRM, SLM and forging technique according to AMS4999,GB/T228 and ISO 10993.The mechanical properties were analyzed by universal test machine. The phase transformation was analyzed by X-ray diffraction and scanning electron microscopy. The corrosivity was analyzed by electrochemical method. The biocompatibility was analyzed by co-culturing with mesenchymal stem cell and analyzed by scanning electron microscopy (SEM) and alkaline phosphatase assay (ALP) to evaluate cell adhesion and differentiation, respectively. Results: The mechanical properties, the phase transformation, the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM、SLM were similar to forging and meet the mechanical property requirements of AMS4999 standard. a­phase microstructure for the EBM production contrast to the a’­phase microstructure of the SLM product. Mesenchymal stem cell adhesion and differentiation were well. Conclusion: The property of the Ti-6Al-4V alloy manufactured by EBRM and SLM technique can meet the medical standard from this study. But some further study should be proceeded in order to applying well in clinical practice.

Keywords: 3D printing, Electron Beam Rapid Manufacturing (EBRM), Selective Laser Melting (SLM), Computer Aided Design (CAD)

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Authors: Heerak Banerjee, Sourov Roy

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Supersymmetry, one of the most celebrated fields of study for explaining experimental observations where the standard model (SM) falls short, is reeling from the lack of experimental vindication. At the same time, the idea of additional gauge symmetry, in particular, the gauged Lμ-Lτ symmetric models have also generated significant interest. They have been extensively proposed in order to explain the tantalizing discrepancy in the predicted and measured value of the muon anomalous magnetic moment alongside several other issues plaguing the SM. While very little parameter space within these models remain unconstrained, this work finds that the γ + Missing Energy (ME) signal at the Belle-II detector will be a smoking gun for supersymmetry (SUSY) in the presence of a gauged U(1)Lμ-Lτ symmetry. A remarkable consequence of breaking the enhanced symmetry appearing in the limit of degenerate (s)leptons is the nondecoupling of the radiative contribution of heavy charged sleptons to the γ-Z΄ kinetic mixing. The signal process, e⁺e⁻ →γZ΄→γ+ME, is an outcome of this ubiquitous feature. Taking the severe constraints on gauged Lμ-Lτ models by several low energy observables into account, it is shown that any significant excess in all but the highest photon energy bin would be an undeniable signature of such heavy scalar fields in SUSY coupling to the additional gauge boson Z΄. The number of signal events depends crucially on the logarithm of the ratio of stau to smuon mass in the presence of SUSY. In addition, the number is also inversely proportional to the e⁺e⁻ collision energy, making a low-energy, high-luminosity collider like Belle-II an ideal testing ground for this channel. This process can probe large swathes of the hitherto free slepton mass ratio vs. additional gauge coupling (gₓ) parameter space. More importantly, it can explore the narrow slice of Z΄ mass (MZ΄) vs. gₓ parameter space still allowed in gauged U(1)Lμ-Lτ models for superheavy sparticles. The spectacular finding that the signal significance is independent of individual slepton masses is an exciting prospect indeed. Further, the prospect that signatures of even superheavy SUSY particles that may have escaped detection at the LHC may show up at the Belle-II detector is an invigorating revelation.

Keywords: additional gauge symmetry, electron-positron collider, kinetic mixing, nondecoupling radiative effect, supersymmetry

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Authors: Igor B. Sivaev

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Design of molecular machines is an extraordinary growing and very important area of research that it was recognized by awarding Sauvage, Stoddart and Feringa the Nobel Prize in Chemistry in 2016 'for the design and synthesis of molecular machines'. Based on the type of motion being performed, molecular machines can be divided into two main types: molecular motors and molecular switches. Molecular switches are molecules or supramolecular complexes having bistability, i.e., the ability to exist in two or more stable forms, among which may be reversible transitions under external influence (heating, lighting, changing the medium acidity, the action of chemicals, exposure to magnetic or electric field). Molecular switches are the main structural element of any molecular electronics devices. Therefore, the design and the study of molecules and supramolecular systems capable of performing mechanical movement is an important and urgent problem of modern chemistry. There is growing interest in molecular switches and other devices of molecular electronics based on transition metal complexes; therefore choice of suitable stable organometallic unit is of great importance. An example of such unit is bis(dicarbollide) complexes of transition metals [3,3’-M(1,2-C₂B₉H₁₁)₂]ⁿ⁻. The control on the ligand rotation in such complexes can be reached by introducing substituents which could provide stabilization of certain rotamers due to specific interactions between the ligands, on the one hand, and which can participate as Lewis bases in complex formation with external metals resulting in a change in the rotation angle of the ligands, on the other hand. A series of isomeric methyl sulfide derivatives of cobalt bis(dicarbollide) complexes containing methyl sulfide substituents at boron atoms in different positions of the pentagonal face of the dicarbollide ligands [8,8’-(MeS)₂-3,3’-Co(1,2-C₂B₉H₁₀)₂]⁻, rac-[4,4’-(MeS)₂-3,3’-Co(1,2-C₂B₉H₁₀)₂]⁻ and meso-[4,7’-(MeS)₂-3,3’-Co(1,2-C₂B₉H₁₀)₂]⁻ were synthesized by the reaction of CoCl₂ with the corresponding methyl sulfide carborane derivatives [10-MeS-7,8-C₂B₉H₁₁)₂]⁻ and [10-MeS-7,8-C₂B₉H₁₁)₂]⁻. In the case of asymmetrically substituted cobalt bis(dicarbollide) complexes the corresponding rac- and meso-isomers were successfully separated by column chromatography as the tetrabutylammonium salts. The compounds obtained were studied by the methods of ¹H, ¹³C, and ¹¹B NMR spectroscopy, single crystal X-ray diffraction, cyclic voltammetry, controlled potential coulometry and quantum chemical calculations. It was found that in the solid state, the transoid- and gauche-conformations of the 8,8’- and 4,4’-isomers are stabilized by four intramolecular CH···S(Me)B hydrogen bonds each one (2.683-2.712 Å and 2.709-2.752 Å, respectively), whereas gauche-conformation of the 4,7’-isomer is stabilized by two intramolecular CH···S hydrogen bonds (2.699-2.711 Å). The existence of the intramolecular CH·S(Me)B hydrogen bonding in solutions was supported by the 1H NMR spectroscopy. These data are in a good agreement with results of the quantum chemical calculations. The corresponding iron and nickel complexes were synthesized as well. The reaction of the methyl sulfide derivatives of cobalt bis(dicarbollide) with various labile transition metal complexes results in rupture of intramolecular hydrogen bonds and complexation of the methyl sulfide groups with external metal. This results in stabilization of other rotational conformation of cobalt bis(dicarbollide) and can be used in design of molecular switches. This work was supported by the Russian Science Foundation (16-13-10331).

Keywords: molecular switches, NMR spectroscopy, single crystal X-ray diffraction, transition metal bis(dicarbollide) complexes, quantum chemical calculations

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Authors: Iwona Cieślik, Władysław Migdał, Kinga Topolska, Ewa Cieślik

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The consumption of fish is recommended as a means of preventing serious diseases, especially cardiovascular problems. Fish is known to be a valuable source of protein (rich in essential amino acids), unsaturated fatty acids, fat-soluble vitamins, macro- and microelements. However, it can also contain several contaminants (e.g. pesticides, heavy metals) that may pose considerable risks for humans. Among others, pesticide are of special concern. Their widespread use has resulted in the contamination of environmental compartments, including water. The occurrence of pesticides in the environment is a serious problem, due to their potential toxicity. Therefore, a systematic monitoring is needed. The aim of the study was to determine the organochlorine and organophosphate pesticide residues in fish muscle tissues of the pike (Esox lucius, L.) and the rainbow trout (Oncorhynchus mykkis, Walbaum) by a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, using Gas Chromatography Quadrupole Mass Spectrometry (GC/Q-MS), working in selected-ion monitoring (SIM) mode. The analysis of α-HCH, β-HCH, lindane, diazinon, disulfoton, δ-HCH, methyl parathion, heptachlor, malathion, aldrin, parathion, heptachlor epoxide, γ-chlordane, endosulfan, α-chlordane, o,p'-DDE, dieldrin, endrin, 4,4'-DDD, ethion, endrin aldehyde, endosulfan sulfate, 4,4'-DDT, and metoxychlor was performed in the samples collected in the Carp Valley (Malopolska region, Poland). The age of the pike (n=6) was 3 years and its weight was 2-3 kg, while the age of the rainbow trout (n=6) was 0.5 year and its weight was 0.5-1.0 kg. Detectable pesticide (HCH isomers, endosulfan isomers, DDT and its metabolites as well as metoxychlor) residues were present in fish samples. However, all these compounds were below the limit of quantification (LOQ). The other examined pesticide residues were below the limit of detection (LOD). Therefore, the levels of contamination were - in all cases - below the default Maximum Residue Levels (MRLs), established by Regulation (EC) No 396/2005 of the European Parliament and of the Council. The monitoring of pesticide residues content in fish is required to minimize potential adverse effects on the environment and human exposure to these contaminants.

Keywords: contaminants, fish, pesticides residues, QuEChERS method

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Authors: Z. O. Apotiola, J. F. Fashakin

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A study was conducted to investigate the storage stability of Mr Chef and Annapurna salts. The salts were bought from Mile 12 market in Lagos State and were stored for a period of six months. The stability of the iodine content was then investigated by storing some at ambient temperature (24-30oC) and some at atmospheric temperature (21-35 oC), and from each storage condition, a sample each was taken every month to analyze for the iodine and moisture contents. The result shows that there was a significant difference between Mr Chef and the standard and Annapurna and the standard. The iodine content of Mr Chef stored at ambient and atmospheric temperature decreases progressively from 48.70±0.00-37.00±0.00 and 47.60±0.00-11.60±0.00 respectively. And that of Annapurna at both ambient and atmospheric temperature also decreases progressively from 47.60±0.00-36.60±0.00 and 47.60±0.00-10.60±0.00 respectively. Also, the moisture content of both salts at the zero month to the sixth month both at room temperature and atmospheric temperature increases from 1.11±0.00-1.70±0.00 and 1.11±0.00-2.40±0.00 respectively. The results of the heavy metals shows that only Copper, Zinc and Cobalt were detected at the first and the sixth month in both Mr Chef and Annapurna which ranges from 0.15±0.00-0.38±0.00 and 0.18±0.00 - 3.50±0.00 respectively. Hence, the stability of iodine in salt is influenced by the storage conditions it is subjected to and the length of time it is been stored.

Keywords: salt, iodine, stability, ambient, atmospheric temperature

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Authors: Asifa Fitriani, Galih Prakoso

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This study aims to improve the design layout of a Micro, Small and Medium Enterprises (SMEs) to minimize material handling and redesigning the layout of production facilities based on the safety and health and standards of food production facilities. Problems layout in the one of chip making industry mushrooms in Indonesia is cross movement between work stations, work accidents, and the standard of facilities that do not conform with the standards of the food industry. Improvement layout design using CORELAP and 5S method to give recommendation and implementation of occupational health and safety standards of food production facilities. From the analysis, improved layout using CORELAP provide a smaller displacement distance is 155.84 meters from the initial displacement distance of 335.9 meters, and providing a shorter processing time than the original 112.726 seconds to 102.831 seconds. 5S method also has recommended the completion of occupational health and safety issues as well as the standard means of food production by changing the working environment better.

Keywords: Layout Design, Corelap, 5S

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Authors: Sharmin Sultana, Reinhard Schlickeiser

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A degenerate relativistic quantum plasma (DRQP) system (containing relativistically degenerate electrons, degenerate/non-degenerate light nuclei, and non-degenerate heavy nuclei) is considered to investigate the propagation characteristics of electrostatic solitary waves (in the ionic scale length) theoretically and numerically. The ion-acoustic solitons are found to be associated with the modified ion-acoustic waves (MIAWs) in which inertia (restoring force) is provided by mass density of the light or heavy nuclei (degenerate pressure of the cold electrons). A mechanical-motion analog (Sagdeev-type) pseudo-potential approach is adopted to study the properties of large amplitude solitary waves. The basic properties of the large amplitude MIAWs and their existence domain in terms of soliton speed (Mach number) are examined. On the other hand, a multi-scale perturbation approach, leading to an evolution equation for the envelope dynamics, is adopted to derive the cubic nonlinear Schrödinger equation (NLSE). The criteria for the occurrence of modulational instability (MI) of the MIAWs are analyzed via the nonlinear dispersion relation of the NLSE. The possibility for the formation of highly energetic localized modes (e.g. peregrine solitons, rogue waves, etc.) is predicted in such DRQP medium. Peregrine solitons or rogue waves with amplitudes of several times of the background are observed to form in DRQP. The basic features of these modulated waves (e.g. envelope solitons, peregrine solitons, and rogue waves), which are found to form in DRQP, and their MI criteria (on the basis of different intrinsic plasma parameters), are investigated. It is emphasized that our results should be useful in understanding the propagation characteristics of localized disturbances and the modulation dynamics of envelope solitons, and their instability criteria in astrophysical DRQP system (e.g. white dwarfs, neutron stars, etc., where matters under extreme conditions are assumed to exist) and also in ultra-high density experimental plasmas.

Keywords: degenerate plasma, envelope solitons, modified ion-acoustic waves, modulational instability, rogue waves

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Authors: Yang Jian-Hong, Zhang Ren-Cheng, Huang Li

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Arc fault is one of the main inducements of electric fires. Arc Fault Detection Device (AFDD) can detect arc fault effectively. Arc fault detections and unhooking standards are the keys to AFDD practical application. First, an arc fault continuous production system was developed, which could count the arc half wave number. Then, Combining with the UL1699 standard, ignition probability curve of cotton and unhooking time of various currents intensity were obtained by experiments. The combustion degree of arc fault could be expressed effectively by arc area. Experiments proved that electric fires would be misjudged or missed only using arc half wave number as AFDD unhooking basis. At last, Practical tests were carried out on the self-developed AFDD system. The result showed that actual AFDD unhooking time was the sum of arc half wave cycling number, Arc wave identification time and unhooking mechanical operation time And the first two shared shorter time. Unhooking time standard depended on the shortest mechanical operation time.

Keywords: arc fault detection device, arc area, arc half wave, unhooking time, arc fault

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Authors: Engida Yisma, Berhanu Dessalegn, Ayalew Astatkie, Nebreed Fesseha

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Background: The World Health Organization (WHO) recommends using the partograph to follow labour and delivery, with the objective to improve health care and reduce maternal and foetal morbidity and death. Methods: A retrospective document review was undertaken to assess the completion of the modified WHO partograph during labour in public health institutions of Addis Ababa, Ethiopia. A total of 420 of the modified WHO partographs used to monitor mothers in labour from five public health institutions that provide maternity care were reviewed. A structured checklist was used to gather the required data. The collected data were analyzed using SPSS version 16.0. Frequency distributions, cross-tabulations and a graph were used to describe the results of the study. Results: All facilities were using the modified WHO partograph. The correct completion of the partograph was very low. From 420 partographs reviewed across all the five health facilities, foetal heart rate was recorded into the recommended standard in 129(30.7%) of the partographs, while 138 (32.9%) of cervical dilatation and 87 (20.70%) of uterine contractions were recorded to the recommended standard. The study did not document descent of the presenting part in 353 (84%). Moulding in 364 (86.7%) of the partographs reviewed was not recorded. Documentation of state of the liquor was 113(26.9%), while the maternal blood pressure was recorded to standard only in 78(18.6%) of the partographs reviewed. Conclusions: This study showed a poor completion of the modified WHO partographs during labour in public health institutions of Addis Ababa, Ethiopia. The findings may reflect poor management of labour and indicate the need for pre-service and periodic on-job training of health workers on the proper completion of the partograph. Regular supportive supervision, provision of guidelines and mandatory health facility policy are also needed in support of a collaborative effort to reduce maternal and perinatal deaths.

Keywords: modified WHO partograph, completion, public health institutions, Addis Ababa, Ethiopia

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Authors: Ran Etgar

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The process of rounding off measurements in continuous variables is commonly encountered. Although it usually has minor effects, sometimes it can lead to poor outcomes in statistical process control using X̄ chart. The traditional control limits can cause incorrect conclusions if applied carelessly. This study looks into the limitations of classical control limits, particularly the impact of asymmetry. An approach to determining the distribution function of the measured parameter ȳ is presented, resulting in a more precise method to establish the upper and lower control limits. The proposed method, while slightly more complex than Shewhart's original idea, is still user-friendly and accurate and only requires the use of two straightforward tables.

Keywords: SPC, round-off data, control limit, rounding error

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Authors: Grace O. Akinlade, Danjuma D. Maza, Oluwakemi O. Olawolu, Delight O. Babalola, John A. O. Oyekunle, Joshua O. Ojo

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The Mokuro area of Ile-Ife, South West Nigeria, was well known for gold mining in the past (about twenty years ago). However, the place has since been reclaimed and converted to residential area without any environmental risk assessment of the impact of the mining tailings on the environment. Soil, water, and plant samples were collected from 4 different locations around the mine-turned-residential area. Soil samples were pulverized and sieved into finer particles, while the plant samples were dried and pulverized. All the samples were digested and analyzed for As, Pb, Cd, and Zn using atomic absorption spectroscopy (AAS). From the analysis results, the hazard index (HI) was then calculated for the metals. The soil and plant samples were air dried and pulverized, then weighed, after which the samples were packed into special and properly sealed containers to prevent radon gas leakage. After the sealing, the samples were kept for 28 days to attain secular equilibrium. The concentrations of 40K, 238U, and 232Th in the samples were measured using a cesium iodide (CsI) spectrometer and URSA software. The AAS analysis showed that As, Pb, Cd (Toxic metals), and Zn (essential trace metals) are in concentrations lower than permissible limits in plants and soil samples, while the water samples had concentrations higher than permissible limits. The calculated health indices (HI) show that HI for water is >1 and that of plants and soil is <1. Gamma spectrometry result shows high levels of activity concentrations above the recommended limits for all the soil and plant samples collected from the area. Only the water samples have activity concentrations below the recommended limit. Consequently, the absorbed dose, annual effective dose, and excess lifetime cancer risk are all above the recommended safe limit for all the samples except for water samples. In conclusion, all the samples collected from the area are either contaminated with toxic metals or they pose radiological hazards to the consumers. Further detailed study is therefore recommended in order to be able to advise the residents appropriately.

Keywords: toxic metals, gamma spectrometry, Ile-Ife, radiological hazards, gold mining

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Authors: Katarzyna Baruch, Agata Szelag, Aleksandra Majchrzak, Tadeusz Kamisinski

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Methodology of measurement of sound absorption coefficient in scaled models is based on the ISO 354 standard. The measurement is realised indirectly - the coefficient is calculated from the reverberation time of an empty chamber as well as a chamber with an inserted sample. It is crucial to maintain the atmospheric conditions stable during both measurements. Possible differences may be amended basing on the formulas for atmospheric attenuation coefficient α given in ISO 9613-1. Model studies require scaling particular factors in compliance with specified characteristic numbers. For absorption coefficient measurement, these are for example: frequency range or the value of attenuation coefficient m. Thanks to the possibilities of modern electroacoustic transducers, it is no longer a problem to scale the frequencies which have to be proportionally higher. However, it may be problematic to reduce values of the attenuation coefficient. It is practically obtained by drying the air down to a defined relative humidity. Despite the change of frequency range and relative humidity of the air, ISO 9613-1 standard still allows the calculation of the amendment for little differences of the atmospheric conditions in the chamber during measurements. The paper discusses a number of theoretical analyses and experimental measurements performed in order to obtain consistency between the values of attenuation coefficient calculated from the formulas given in the standard and by measurement. The authors performed measurements of reverberation time in a chamber made in a 1/8 scale in a corresponding frequency range, i.e. 800 Hz - 40 kHz and in different values of the relative air humidity (40% 5%). Based on the measurements, empirical values of attenuation coefficient were calculated and compared with theoretical ones. In general, the values correspond with each other, but for high frequencies and low values of relative air humidity the differences are significant. Those discrepancies may directly influence the values of measured sound absorption coefficient and cause errors. Therefore, the authors made an effort to determine an amendment minimizing described inaccuracy.

Keywords: air absorption correction, attenuation coefficient, dimensional analysis, model study, scaled modelling

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Authors: Jagdish Prasad Sahoo

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The increase in active earth pressure during the event of an earthquake results sliding, overturning and tilting of earth retaining structures. In order to improve upon the stability of structures, the soil mass is often reinforced with various types of reinforcements such as metal strips, geotextiles, and geogrids etc. The stresses generated in the soil mass are transferred to the reinforcements through the interface friction between the earth and the reinforcement, which in turn reduces the lateral earth pressure on the retaining walls. Hence, the evaluation of earth pressure in the presence of seismic forces with an inclusion of reinforcements is important for the design retaining walls in the seismically active zones. In the present analysis, the effect of reinforcing horizontal layers of reinforcements in the form of sheets (Geotextiles and Geogrids) in sand used as backfill, on reducing the active earth pressure due to earthquake body forces has been studied. For carrying out the analysis, pseudo-static approach has been adopted by employing upper bound theorem of limit analysis in combination with finite elements and linear optimization. The computations have been performed with and out reinforcements for different internal friction angle of sand varying from 30 ° to 45 °. The effectiveness of the reinforcement in reducing the active earth pressure on the retaining walls is examined in terms of active earth pressure coefficient for presenting the solutions in a non-dimensional form. The active earth pressure coefficient is expressed as functions of internal friction angle of sand, interface friction angle between sand and reinforcement, soil-wall interface roughness conditions, and coefficient of horizontal seismic acceleration. It has been found that (i) there always exists a certain optimum depth of the reinforcement layers corresponding to which the value of active earth pressure coefficient becomes always the minimum, and (ii) the active earth pressure coefficient decreases significantly with an increase in length of reinforcements only up to a certain length beyond which a further increase in length hardly causes any reduction in the values active earth pressure. The optimum depth of the reinforcement layers and the required length of reinforcements corresponding to the optimum depth of reinforcements have been established. The numerical results developed in this analysis are expected to be useful for purpose of design of retaining walls.

Keywords: active, finite elements, limit analysis, presudo-static, reinforcement

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Authors: Lee Bih Ni, Kiu Su Na

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This paper discusses the Chinese Language Teaching as a Second Language by focusing on Immersion Teaching. Researchers used narrative literature review to describe the current states of both art and science in focused areas of inquiry. Immersion teaching comes with a standard that teachers must reliably meet. Chinese language-immersion instruction consists of language and content lessons, including functional usage of the language, academic language, authentic language, and correct Chinese sociocultural language. Researchers used narrative literature reviews to build a scientific knowledge base. Researchers collected all the important points of discussion, and put them here with reference to the specific field where this paper is originally based on. The findings show that Chinese Language in immersion teaching is not like standard foreign language classroom; immersion setting provides more opportunities to teach students colloquial language than academic. Immersion techniques also introduce a language’s cultural and social contexts in a meaningful and memorable way. It is particularly important that immersion teachers connect classwork with real-life experiences. Immersion also includes more elements of discovery and inquiry based learning than do other kinds of instructional practices. Students are always and consistently interpreted the conclusions and context clues.

Keywords: a second language, Chinese language teaching, immersion teaching, instructional strategies

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Authors: Iván Castelló, Georgiana Stoica, Emilio Palomares, Fernando Bravo

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We present herein two colour encoded silica nanospheres (2nanoSi) for the fluorescence quantitative ratiometric determination of trypsin in humans. The system proved to be a faster (minutes) method, with two times higher sensitivity than the state-of-the-art biomarkers based sensors for cystic fibrosis (CF), allowing the quantification of trypsin concentrations in a wide range (0-350 mg/L). Furthermore, as trypsin is directly related to the development of cystic fibrosis, different human genotypes, i.e. healthy homozygotic (> 80 mg/L), CF homozygotic (< 50 mg/L), and heterozygotic (> 50 mg/L), respectively, can be determined using our 2nanoSi nanospheres.

Keywords: cystic fibrosis, trypsin, quantum dots, biomarker, homozygote, heterozygote

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Authors: Alexandra Sweny

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This paper contends with the intersection between the act of witnessing and the act of reading in order to consider the relevance of literary testimony and fiction as tools for postcolonial readings of history. J. M. Coetzee's Waiting for the Barbarians elucidates what Primo Levi deems the 'paradoxical' task of testimony: that suffering can only be fully narrated by the sufferer themselves, whose voice and narrative capacity is often foreclosed by the very extent of their trauma. By examining the fictional Magistrate's position as both a reader and translator of history, this paper posits Waiting for the Barbarians as an ethical command against the appropriation of trauma.

Keywords: ethical criticism, limit-experience, postcolonialism, psychic trauma in literature, testimony

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Authors: Carlos Alberto Rivera-corredor, Angie Dayana Vargas-Ceballos, Edison Gilpavas, Izabela Dobrosz-Gómez, Miguel Ángel Gómez-García

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Hexavalent chromium, Cr (VI) is present in the effluents from different industries such as electroplating, mining, leather tanning, etc. This compound is of great academic and industrial concern because of its toxic and carcinogenic behavior. Its dumping to both environmental and public health for animals and humans causes serious problems in water sources. The amount of Cr (VI) in industrial wastewaters ranges from 0.5 to 270,000 mgL-1. According to the Colombian standard for water quality (NTC-813-2010), the maximum allowed concentration for the Cr (VI) in drinking water is 0.05 mg L-1. To comply with this limit, it is essential that industries treat their effluent to reduce the Cr (VI) to acceptable levels. Numerous methods have been reported for the treatment removing metal ions from aqueous solutions such as: reduction, ion exchange, electrodialysis, etc. Adsorption has become a promising method for the purification of metal ions in water, since its application corresponds with an economic and efficient technology. The absorbent selection and the kinetic and thermodynamic study of the adsorption conditions are key to the development of a suitable adsorption technology. The Ce0.25Zr0.75O2.nH2O presents higher adsorption capacity between a series of hydrated mixed oxides Ce1-xZrxO2 (x = 0, 0.25, 0.5, 0.75, 1). This work presents the kinetic and thermodynamic study of Cr (VI) adsorption on Ce0.25Zr0.75O2.nH2O. Experiments were performed under the following experimental conditions: initial Cr (VI) concentration = 25, 50 and 100 mgL-1, pH = 2, adsorbent charge = 4 gL-1, stirring time = 60 min, temperature=20, 28 and 40 °C. The Cr (VI) concentration was spectrophotometrically estimated by the method of difenilcarbazide with monitoring the absorbance at 540 nm. The Cr (VI) adsorption over hydrated Ce0.25Zr0.75O2.nH2O models was analyzed using pseudo-first and pseudo-second order kinetics. The Langmuir and Freundlich models were used to model the experimental data. The convergence between the experimental values and those predicted by the model, is expressed as a linear regression correlation coefficient (R2) and was employed as the model selection criterion. The adsorption process followed the pseudo-second order kinetic model and obeyed the Langmuir isotherm model. The thermodynamic parameters were calculated as: ΔH°=9.04 kJmol-1,ΔS°=0.03 kJmol-1 K-1, ΔG°=-0.35 kJmol-1 and indicated the endothermic and spontaneous nature of the adsorption process, governed by physisorption interactions.

Keywords: adsorption, hexavalent chromium, kinetics, thermodynamics

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Authors: Arash Gharibi

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Mankind has always used models to solve problems. Essentially, models are simplified versions of reality, whose need stems from having to deal with complexity; many processes or phenomena are too complex to be described completely. Thus a fundamental model requirement is that it contains the characteristic features that are essential in the context of the problem to be solved or described. Models are used in virtually every scientific domain to deal with various problems. During the recent decades, the number of models has increased exponentially. Publication of models as part of original research has traditionally been in in scientific periodicals, series, monographs, agency reports, national journals and laboratory reports. This makes it difficult for interested groups and communities to stay informed about the state-of-the-art. During the modeling process, many important decisions are made which impact the final form of the model. Without a record of these considerations, the final model remains ill-defined and open to varying interpretations. Unfortunately, the details of these considerations are often lost or in case there is any existing information about a model, it is likely to be written intuitively in different layouts and in different degrees of detail. In order to overcome these issues, different domains have attempted to implement their own approaches to preserve their models’ information in forms of model documentation. The most frequently cited model documentation approaches show that they are domain specific, not to applicable to the existing models and evolutionary flexibility and intrinsic corrections and improvements are not possible with the current approaches. These issues are all because of a lack of unified standards for model documentation. As a way forward, this research will propose a new standard for capturing and managing models’ information in a unified way so that interoperability and reusability of models become possible. This standard will also be evolutionary, meaning members of modeling realm could contribute to its ongoing developments and improvements. In this paper, the current 3 of the most common metamodels are reviewed and according to pros and cons of each, a new metamodel is proposed.

Keywords: metamodel, modeling, interoperability, reuse

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Authors: Charirat Kusonwiriyawong, Supha Photichan, Wannarut Chutibutr

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Soil test kits for rapid analysis of the organic matter, available phosphorus and exchangeable potassium were developed to drive a low-cost field testing kit to farmers. The objective was to provide a decision tool for improving soil fertility. One aspect of soil test kit development was ease of use which is a time requirement for completing organic matter, available phosphorus and exchangeable potassium test in one soil sample. This testing kit required only two extractions and utilized no filtration consuming approximately 15 minutes per sample. Organic matter was principally created by oxidizing carbon KMnO₄ using the standard color chart. In addition, modified single extractant (Mehlich I) was applied to extract available phosphorus and exchangeable potassium. Molybdenum blue method and turbidimetric method using standard color chart were adapted to analyze available phosphorus and exchangeable potassium, respectively. Modified single extractant using in soil test kits were highly significant matching with analytical laboratory results (r=0.959** and 0.945** for available phosphorus and exchangeable potassium, respectively). Linear regressions were statistically calculated between modified single extractant and standard laboratory analysis (y=0.9581x-12.973 for available phosphorus and y=0.5372x+15.283 for exchangeable potassium, respectively). These equations were calibrated to formulate a fertilizer rate recommendation for specific corps. To validate quality, soil test kits were distributed to farmers and extension workers. We found that the accuracy of soil test kits were 71.0%, 63.9% and 65.5% for organic matter, available phosphorus, and exchangeable potassium, respectively. The quantitative survey was also conducted in order to assess their satisfaction with soil test kits. The survey showed that more than 85% of respondents said these testing kits were more convenient, economical and reliable than the other commercial soil test kits. Based upon the finding of this study, soil test kits can be another alternative for providing soil analysis and fertility recommendations when a soil testing laboratory is not available.

Keywords: available phosphorus, exchangeable potassium, modified single extractant, organic matter, soil test kits

Procedia PDF Downloads 142

Authors: Mrinal Kanti Bhowmik, Usha Rani Gogoi Jr., Anjan Kumar Ghosh, Debotosh Bhattacharjee

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In the last few decades, breast thermography has achieved an average sensitivity and specificity of 90% for breast tumor detection. Breast thermography is a non-invasive, cost-effective, painless and radiation-free breast imaging modality which makes a significant contribution to the evaluation and diagnosis of patients, suspected of having breast cancer. An abnormal breast thermogram may indicate significant biological risk for the existence or the development of breast tumors. Breast thermography can detect a breast tumor, when the tumor is in its early stage or when the tumor is in a dense breast. The infrared breast thermography is very sensitive to environmental changes for which acquisition of breast thermography should be performed under strictly controlled conditions by undergoing some standard protocols. Several factors like air, temperature, humidity, etc. are there to be considered for characterizing thermal images as an imperative tool for detecting breast cancer. A detailed study of various breast thermogram acquisition protocols adopted by different researchers in their research work is provided here in this paper. After going through a rigorous study of different breast thermogram acquisition protocols, a new standard breast thermography acquisition setup is proposed here in this paper for proper and accurate capturing of the breast thermograms. The proposed breast thermogram acquisition setup is being built in the Radiology Department, Agartala Government Medical College (AGMC), Govt. of Tripura, Tripura, India. The breast thermograms are captured using FLIR T650sc thermal camera with the thermal sensitivity of 20 mK at 30 degree C. The paper is an attempt to highlight the importance of different critical parameters of breast thermography like different thermography views, patient preparation protocols, acquisition room requirements, acquisition system requirements, etc. This paper makes an important contribution by providing a detailed survey and a new efficient approach on breast thermogram capturing.

Keywords: acquisition protocol, breast cancer, breast thermography, infrared thermography

Procedia PDF Downloads 394

Authors: Pouya Molana, Zeinab Alimohammadi

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Determining wind wave characteristics is essential for implementing projects related to Coastal and Marine engineering such as designing coastal and marine structures, estimating sediment transport rates and coastal erosion rates in order to predict significant wave height (H_s), this study applies the third generation spectral wave model, Mike 21 SW, along with CEM model. For SW model calibration and verification, two data sets of meteorology and wave spectroscopy are used. The model was exposed to time-varying wind power and the results showed that difference ratio mean, standard deviation of difference ratio and correlation coefficient in SW model for H_s parameter are 1.102, 0.279 and 0.983, respectively. Whereas, the difference ratio mean, standard deviation and correlation coefficient in The Choice Experiment Method (CEM) for the same parameter are 0.869, 1.317 and 0.8359, respectively. Comparing these expected results it is revealed that the Choice Experiment Method CEM has more errors in comparison to MIKE 21 SW third generation spectral wave model and higher correlation coefficient does not necessarily mean higher accuracy.

Keywords: MIKE 21 SW, CEM method, significant wave height, difference ratio

Procedia PDF Downloads 395

Authors: Nwanneka Mmonwuba

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Solid waste disposal to the environment was investigated by analyzing the quality characteristics of waste, air quality, and heavy metal concentration in the soil. The characteristics of waste were analyzed by enumerating the number of houses, hostels, hotels, markets, schools, and industries with the type of waste being discharged or deposited into the dump site. The percentage of waste was estimated with organic ranking first for both wet and dry seasons, 54% and 44%, respectively. The ambient air quality was analyzed using the crown gas monitor analyzer. The analysis showed that the mean concentration of NO₂, SO₂, and Co is 0.74, 0.37, and 47.35 ppm for the wet season and 0.47, 0.35, and 37.65 ppm for the dry season, respectively, and do not conform with the USEPA standard. The chemical analysis of the groundwater sample indicates alkalinity ranging from 7.38 to 9.11. the heavy metals concentration in the soil of cadmium, iron, copper, calcium, and potassium with 0.053, 0.722, 0227, 21.3, and 9.019, respectively, obtained from 0.3 m at the subsurface failed to conform to the NRC (2013) standard. Iron consent in the soil can be corrected using ascorbic acid and soda ash. The permanent reduction of effects is to try relocating people who live very close to the dumpsite, or the dumpsite should be sited elsewhere and replaced with a sanitary landfill.

Keywords: solid waste, groundwater, disposal, dumpsite

Procedia PDF Downloads 43

Authors: Abimbola Motunrayo Enitan, Ibironke Titilayo Enitan, John Odiyo

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The study assessed quality of surface water across Ndawuse River Phase 1, District of the Federal Capital Territory (FCT), Abuja, Nigeria based on physico-chemical variables that are linked to agrochemical and eutrophication, as well as heavy metals concentrations. In total, sixteen surface water samples were obtained from five locations along the river. The results were compared with the standard limits set by both World Health Organization and Federal Environmental Protection Agency for drinking water. The results obtained indicated that BOD5, turbidity, 0.014-3.511 mg Fe/L and 0.078-0.14 mg Cr/L were all above the standard limits. The results further showed that the quality of surface water is being significantly affected by human activities around the Ndawuse River which could pose an adverse health risk to several communities that rely on these receiving water bodies primarily as their source of water. Therefore, there is a need for strict enforcement of environmental laws considering the physico-chemical analysis.

Keywords: Abuja, heavy metals, human exposure risk, Ndawuse River, Nigeria, surface water

Procedia PDF Downloads 260

Authors: M. Marchewka

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The article is devoted to the possible optical transitions in double quantum wells system based on HgTe/HgCd(Mn)Te heterostructures. Such structures can find applications as detectors and sources of radiation in the terahertz range. The Double Quantum Wells (DQW) systems consist of two QWs separated by the transparent for electrons barrier. Such systems look promising from the point of view of the additional degrees of freedom. In the case of the topological insulator in about 6.4nm wide HgTe QW or strained 3D HgTe films at the interfaces, the topologically protected surface states appear at the interfaces/surfaces. Electrons in those edge states move along the interfaces/surfaces without backscattering due to time-reversal symmetry. Combination of the topological properties, which was already verified by the experimental way, together with the very well know properties of the DQWs, can be very interesting from the applications point of view, especially in the THz area. It is important that at the present stage, the technology makes it possible to create high-quality structures of this type, and intensive experimental and theoretical studies of their properties are already underway. The idea presented in this paper is based on the eight-band KP model, including the additional terms related to the structural inversion asymmetry, interfaces inversion asymmetry, the influence of the magnetically content, and the uniaxial strain describe the full pictures of the possible real structure. All of this term, together with the external electric field, can be sources of breaking symmetry in investigated materials. Using the 8 band KP model, we investigated the electronic shape structure with and without magnetic field from the application point of view as a THz detector in a small magnetic field (below 2T). We believe that such structures are the way to get the tunable topological insulators and the multilayer topological insulator. Using the one-dimensional electrons at the topologically protected interface states as fast and collision-free signal carriers as charge and signal carriers, the detection of the optical signal should be fast, which is very important in the high-resolution detection of signals in the THz range. The proposed engineering of the investigated structures is now one of the important steps on the way to get the proper structures with predicted properties.

Keywords: topological insulator, THz spectroscopy, KP model, II-VI compounds

Procedia PDF Downloads 115

Authors: Renata Markiewicz-Żukowska, Patryk Nowakowski, Sylwia K. Naliwajko, Jakub M. Bołtryk, Katarzyna Socha, Anna Puścion-Jakubik, Jolanta Soroczyńska, Maria H. Borawska

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Selenium (Se) is an essential element for human health. As an integral part of glutathione peroxidase, it has antioxidant, anti-inflammatory and anticancer activities. Unfortunately, Se dietary intake is often insufficient, especially in regions where the soil is low in Se. Therefore, in search for good sources of Se, the content of this element in food products should be monitored. Food product can be considered as a source of Se when its standard portion covers above 15% of recommended daily allowance. In the case of nuts, 42g is recognized as the standard portion. The aim of this study was to determine the Se content in nuts and to answer the question of whether the studied nuts can be considered as a source of Se in the diet. The material for the study consisted of 10 types of nuts (12 samples of each one): almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, peanuts, pecans, pine nuts, pistachios and walnuts. The nuts were mineralized using microwave technique (Berghof, Germany). The content of Se was determined by atomic absorption spectrometry method with electrothermal atomization in a graphite tube with Zeeman background correction (Hitachi, Japan). The accuracy of the method was verified on certified reference material: Simulated Diet D. The statistical analysis was performed using Statistica v. 13.0 software. Statistical significance was determined at p < 0.05 level. The highest content of Se was found in Brazil nuts (4566.21 ± 3393.9 µg/kg) and the lowest in almonds (36.07 ± 18.8 µg/kg). A standard portion (42g) of almonds, brazil nuts, cashews, hazelnuts, macadamia nuts, peanuts, pecans, pine nuts, pistachios and walnuts covers the recommended daily allowance for Se respectively in: 2, 192, 28, 2, 16, 7, 4, 3, 12, 6%. Brazil nuts, cashews and macadamia nuts can be considered as a good source of Se in diet.

Keywords: atomic absorption spectrometry, diet, nuts, selenium

Procedia PDF Downloads 181

Authors: Olu Ale, Olugbenga Aribisala, Sanmi Awopetu

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Groundwater (Wells) is obtained from several well-defined and different water-bearing geological layers or strata. The physical, chemical and bacteriological quality of the water contributed from each of these water-bearing formations and resultant effects of indiscriminate wastes disposal will be dependent on the dissolution of material within the formation. Therefore, water withdrawn from any ground water source will be a composite of these individual aquifers. The water quality was determined by actual sampling and analysis of the completed wells. This study attempted to examine the physicochemical and bacteriological water quality of twenty five selected wells comprising twenty boreholes (deep wells) and five hand dug wells (shallow wells). The twenty five wells cut across the entire Ado Ekiti Metropolitan area. The water samples collected using standard method was promptly taken to water laboratory at the Federal Polytechnic Ado-Ekiti for analysis, physical, chemical and bacteriological tests were carried out. Quality characteristics tested were found to meet WHO’s standard and generally acceptable, making it potable for drinking in most situations, thus encouraging the use of groundwater. Possible improvement strategies to groundwater exploitation were highlighted while remedies to poor quality water were suggested.

Keywords: bacteriological, physicochemical, quality, wells, Ado Ekiti

Procedia PDF Downloads 363

Authors: Ala Rakhshandeh, Zahra Ashkar, Solmaz Dehghani Dolatabadi, Hossein Bayat

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The present study has been conducted to investigate the role of family emotional climate and emotional expression style in the academic well-being of students with military parents. Children, including 280 female students of Shahriar police officers, were selected by random sampling method, and they have been investigated through Alfred B. Hillburn's family emotional climate questionnaire (1964), King and Ammon's emotional expression questionnaire (1990), and Pitrinen, Sweeney, and Falto's academic well-being questionnaire (2014). The data were analyzed using statistical methods of correlation coefficient and stepwise multiple regression under the SPSS23 program. The results reveal that the variables of family emotional climate and emotional expression can explain 36.4% of the variance in academic well-being. This finding reveals that with an increase of standard deviation on the scores of family emotional climate and emotional expression, 0.513 and 0.155 standard deviations are added to the scores of academic well-being, respectively. The emotional climate of the family has a superior distinctive role in predicting the educational well-being of female students. Thus, the emotional climate of the family and the style of emotional expression play a meaningful role in the academic well-being of students with the military parent.

Keywords: emotional climate, family, emotional expression style, academic well-being

Procedia PDF Downloads 104

Authors: K. Szymkowska, K. Mojsiewicz- Pieńkowska

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Siloxanes are a common ingredients in medicinal products used on the skin, as well as cosmetics. It is widely believed that the silicones are not capable of overcoming the skin barrier. The aim of the study was to verify the possibility of penetration and permeation of linear siloxanes through human skin and determine depth penetration limit of these compounds. Based on the results it was found that human skin is not a barrier for linear siloxanes. PDMS 50 cSt was not identified in the dermis suggests that this molecular size of silicones (3780Da) is safe when it is used in the skin formulations.

Keywords: linear siloxanes, methyl siloxanes, skin penetration, skin permeation

Procedia PDF Downloads 398

Authors: Daniel R. Zeh, Michelle R. Heupel, Mark Hamann, Rhondda Jones, Colin J. Limpus, Helene Marsh

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Marine mammals live in an environment with water temperatures nearly always lower than the mammalian core body temperature of 35 - 38°C. Marine mammals can lose heat at high rates and have evolved a range of adaptations to minimise heat loss. Our project tracked dugongs to examine if there was a discoverable relationship between the animals’ movements and the temperature of their environment that might suggest behavioural thermoregulation. Twenty-nine dugongs were fitted with acoustic and satellite/GPS transmitters in 2012, 2013 and 2014 in Moreton Bay Queensland at the high latitude limit of the species’ winter range in eastern Australia on 30 occasions (one animal was tagged twice). All 22 animals that stayed in the area and had functional transmitters made at least one (and up to 66) return trip(s) to the warmer oceanic waters outside the bay where seagrass is unavailable. Individual dugongs went in and out of the bay in synchrony with the tides and typically spent about 6 hours in the oceanic water. There was a diel pattern in the movements: 85% of outgoing trips occurred between midnight and noon. There were significant individual differences, but the likelihood of a dugong leaving the bay was independent of body length or sex. In Quarter 2 (April – June), the odds of a dugong making a trip increased by about 40% for each 1°C increase in the temperature difference between the bay and the warmer adjacent oceanic waters. In Quarter 3, the odds of making a trip were lower when the outside –inside bay temperature differences were small or negative but increased by a factor of up to 2.12 for each 1°C difference in outside – inside temperatures. In Quarter 4, the odds of making a trip were higher when it was cooler outside the bay and decreased by a factor of nearly 0.5 for each 1°C difference in outside – inside bay temperatures. The activity spaces of the dugongs generally declined as winter progressed suggesting a change in the cost-effectiveness of moving outside the bay. Our analysis suggests that dugongs can thermoregulate their core temperature through the behaviour of moving to water having more favourable temperature.

Keywords: acoustic, behavioral thermoregulation, dugongs, movements, satellite, telemetry, quick fix GPS

Procedia PDF Downloads 170

Authors: Zemirline Adel, Ouali Mohammed, Mahieddine Ali

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The FOSDT (First Order Shear Deformation Theory) is taking into consideration to study the static behavior of a bimorph beam, with a delamination zone between the upper and the lower layer. The effect of limit conditions and lengths of the delamination zone are presented in this paper, with a PVDF piezoelectric material application. A FEM “Finite Element Method” is used to discretize the beam. In the axial displacement, a displacement field appears in the debonded zone with inverse effect between the upper and the lower layer was observed.

Keywords: static, piezoelectricity, beam, delamination

Procedia PDF Downloads 412