Search results for: Initial relative spacing

Authors: Ibrahim Abdel Gadir Malik, Dafalla Siddig Dafalla, Osama Abdelgadir El-Bushra

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Geological and engineering characteristics of intact rock and the discontinuity surfaces was used to describe and classify rock mass into zones based on mechanical and physical properties. Many conditions terms that affect the rock mas; such as Rock strength, Rock Quality Designation (RQD) value, joint spacing, and condition of joint, water condition with block size, joint roughness, separation, joint hardness, friction angle and weathering were used to classify the rock mass into: Good quality (class II) (RMR values range between 75% and 56%), Good to fair quality (class II to III) (RMR values range between 70% and 55%), Fair quality (class III) (RMR values range between 60% and 50%) and Fair to poor quality (Class III to IV) (RMR values, range between (50% and 35%).

Keywords: rock strength, RQD, joints, weathering

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Authors: Ghulam Hasan Abbasi, Moazzam Jamil, M. Anwar-Ul-Haq

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Heavy metals are significant pollutants in environment and their toxicity is a problem for survival of living things while Silicon (Si) is one of the most ubiquitous macroelements, performing an essential function in healing plants in response to environmental stresses. A hydroponic experiment was conducted to investigate the role of exogenous application of silicon under cadmium stress in six different maize hybrids with five treatments comprising of control, 7.5 µM Cd + 5 mM Si, 7.5 µM Cd + 10 mM Si, 15 µM Cd + 5 mM Si and 15 µM Cd + 10 mM Si. Results revealed that treatments of plants with 10mM Si application under both 7.5µM Cd and 15 µM Cd stress resulted in maximum improvement in plant morphological attributes (root and shoot length, root and shoot fresh and dry weight, leaf area and relative water contents) and antioxidant enzymes (POD and CAT) relative to 5 mM Si application in all maize hybrids. Results regarding Cd concentrations showed that Cd was more retained in roots followed by shoots and then leaves and maximum reduction in Cd uptake was observed at 10mM Si application. Maize hybrid 6525 showed maximum growth and least concentration of Cd whereas maize hybrid 1543 showed the minimum growth and maximum Cd concentration among all maize hybrids.

Keywords: antioxidant, cadmium, maize, silicon

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Authors: Atara Shriki, Ilana Lavy

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In a rapidly changing technological society, creativity is considered as an engine of economic and social progress. No doubt the education system has a central role in nurturing all students’ creativity, however, it is normally not encouraged at school. The causes of this reality are related to a variety of circumstances, among them: external pressures to cover the curriculum and succeed in standardized tests that mostly require algorithmic thinking and implementation of rules; teachers’ tendency to teach similarly to the way they themselves were taught as school students; relating creativity to giftedness, and therefore avoid nurturing all students' creativity; lack of adequate learning materials and accessible tools for following and evaluating the development of students’ creativity; and more. Since success in academic studies requires, among other things, creativity, lecturers in higher education institutions should consider appropriate ways to nurture students’ creative thinking and assess its development. Obviously, creativity has a multifaceted nature, numerous definitions, various perspectives for studying its essence (e.g., process, personality, environment, and product), and several approaches aimed at evaluating and assessing creative expressions (e.g., cognitive, social-personal, and psychometric). In this framework, we suggest nurturing students’ creativity through engaging them in problem posing activities that are part of inquiry assignments. In order to assess the development of their creativity, we propose to employ a model that was designed for this purpose, based on the psychometric approach, viewing the posed problems as the “creative product”. The model considers four measurable aspects- fluency, flexibility, originality, and organization, as well as a total score of creativity that reflects the relative weights of each aspect. The scores given to learners are of two types: (1) Total scores- the absolute number of posed problems with respect to each of the four aspects, and a final score of creativity; (2) Relative scores- each absolute number is transformed into a number that relates to the relative infrequency of the posed problems in student’s reference group. Through converting the scores received over time into a graphical display, students can assess their progress both with respect to themselves and relative to their reference group. Course lecturers can get a picture of the strengths and weaknesses of each student as well as the class as a whole, and to track changes that occur over time in response to the learning environment they had generated. Such tracking may assist lecturers in making pedagogical decisions about emphases that should be put on one or more aspects of creativity, and about the students that should be given a special attention. Our experience indicates that schoolteachers and lecturers in higher education institutes find the combination of engaging learners in problem posing along with self-assessment of their progress through utilizing the graphical display of accumulating total and relative scores has the potential to realize most learners’ creative potential.

Keywords: creativity, problem posing, psychometric model, self-assessment

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Authors: Ali Al Moussaoui

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An experiment was designed to assess the performance of 24 Lebanese adults (mean age 29:5 years) in a lexical decision making (LDM) task to find out how the facilitatory effect of phonological priming (PP) affects the speed of visual word recognition in Arabic as lexicality (wordhood) and phonological overlap positions (POP) vary. The experiment falls in line with previous research on phonological priming in the light of the cohort theory and in relation to visual word recognition. The experiment also departs from the research on the Arabic language in which the importance of the consonantal root as a distinct morphological unit is confirmed. Based on previous research, it is hypothesized that (1) PP has a facilitating effect in LDM with words but not with nonwords and (2) final phonological overlap between the prime and the target is more facilitatory than initial overlap. An LDM task was programmed on PsychoPy application. Participants had to decide if a target (e.g., bayn ‘between’) preceded by a prime (e.g., bayt ‘house’) is a word or not. There were 4 conditions: no PP (NP), nonwords priming nonwords (NN), nonwords priming words (NW), and words priming words (WW). The conditions were simultaneously controlled for word length, wordhood, and POP. The interstimulus interval was 700 ms. Within the PP conditions, POP was controlled for in which there were 3 overlap positions between the primes and the targets: initial (e.g., asad ‘lion’ and asaf ‘sorrow’), final (e.g., kattab ‘cause to write’ 2sg-mas and rattab ‘organize’ 2sg-mas), or two-segmented (e.g., namle ‘ant’ and naħle ‘bee’). There were 96 trials, 24 in each condition, using a within-subject design. The results show that concerning (1), the highest average reaction time (RT) is that in NN, followed firstly by NW and finally by WW. There is statistical significance only between the pairs NN-NW and NN-WW. Regarding (2), the shortest RT is that in the two-segmented overlap condition, followed by the final POP in the first place and the initial POP in the last place. The difference between the two-segmented and the initial overlap is significant, while other pairwise comparisons are not. Based on these results, PP emerges as a facilitatory phenomenon that is highly sensitive to lexicality and POP. While PP can have a facilitating effect under lexicality, it shows no facilitation in its absence, which intersects with several previous findings. Participants are found to be more sensitive to the final phonological overlap than the initial overlap, which also coincides with a body of earlier literature. The results contradict the cohort theory’s stress on the onset overlap position and, instead, give more weight to final overlap, and even heavier weight to the two-segmented one. In conclusion, this study confirms the facilitating effect of PP with words but not when stimuli (at least the primes and at most both the primes and targets) are nonwords. It also shows that the two-segmented priming is the most influential in LDM in Arabic.

Keywords: lexicality, phonological overlap positions, phonological priming, visual word recognition

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Authors: Omid Khaiyat, David Hawkes

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Introduction: There remains a lack of information on sophisticated coordination patterns across shoulder girdle muscles. Considering the stability of the shoulder being heavily dependent on coordinated muscle activity during its wide-ranging movements, it is important that key intermuscular relationships are well-defined for a better understanding of underlying pathology. This study investigated shoulder intermuscular coordination during different planes of shoulder elevation. Materials and Methods: EMG was recorded from 14 shoulder muscles in 20 healthy participants during shoulder flexion, scapula plane elevation, abduction, and extension. Cross-correlation by means of Pearson Correlation Coefficient (PCC) was used to examine the coordination between different muscles and muscle groups. Results: Coordination between rotator cuff and deltoid muscle groups was significantly higher (p =0.020-0.035) during the initial (PCC) = 0.79) and final (PCC = 0.74) phases of elevation compared to the mid-range (PCC = 0.34). Furthermore, a high level of coordination (PCC = 0.89) was noted between the deltoid group and the adductor group (latissimus dorsi and teres major) during the initial stage of shoulder elevation. Conclusion: The destabilising force of the deltoid during the initial stage of shoulder elevation is balanced by coordinated activity of rotator cuff, latissimus dorsi, and teres major. This is also the case for the end-range of movement, where increased demand for stability again leads to higher coordination between the deltoid and rotator cuff muscle groups. Appreciation of the sophistication of normal shoulder function evidence-based rehabilitation strategies for conditions such as subacromial impingement syndrome or shoulder instability can be developed.

Keywords: shoulder, coordination, EMG, muscle activity, upper limb

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Authors: Y. Yang, Dian Ming Xing, Qiu Hua Du

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Based on the Motorized Momentum Exchange Tether (MMET), with the principle of momentum exchange, the three dimension flexible dynamics of continuous cislunar payloads transferring system (CCPTS) is built by Lagrange method and its numerical solution is solved by Mathematica software. In the derivation precession of potential energy, this paper uses the Tylor expansion method to simplify the Lagrange equation. Furthermore, the tension coming from the centripetal load is considered in the elastic potential energy. The comparison simulation results between the 3D rigid model and 3D flexible model of CCPTS shows that the tether flexibility has important influence on CCPTS’s orbital parameters (such as radius of CCPTS’s COM and the true anomaly) and the tether’s rotational movement, the relative deviation of radius and the true anomaly between the two dynamic models is about 0.00678% and 0.00259%, the relative deviation of the angle of tether-span and local gravity gradient is about 3.55%. Additionally, the external torque has an apparent influence on the tether’s axial vibration.

Keywords: cislunar transfer, dynamics, momentum exchange, tether

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Authors: Ketevan Janashia, Tamar Tsibadze, Levan Tvildiani, Nikoloz Invia, Elguja Kubaneishvili, Vasili Kukhianidze, George Ramishvili

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This study considers the possible effects of geomagnetic activity (GMA) on humans situated on Earth by performing experiments concerning specific sensitive reactions in humans in both: natural conditions during different GMA and by the simulation of different GMA in the lab. The measurements of autonomic nervous system (ANS) responses to different GMA via measuring the heart rate variability (HRV) indices and stress index (SI) and their comparison with the K-index of GMA have been presented and discussed. The results of experiments indicate an intensification of the sympathetic part of the ANS as a stress reaction of the human organism when it is exposed to high level of GMA as natural as well as in simulated conditions. Aim: We tested the hypothesis whether the GMF when disturbed can have effects on human ANS causing specific sensitive stress-reactions depending on the initial type of ANS. Methods: The study focuses on the effects of different GMA on ANS by comparing of HRV indices and stress index (SI) of n= 78, 18-24 years old healthy male volunteers. Experiments were performed as natural conditions on days of low (K= 1-3) and high (K= 5-7) GMA as well as in the lab by the simulation of different GMA using the device of geomagnetic storm (GMS) compensation and simulation. Results: In comparison with days of low GMA (K=1-3) the initial values of HRV shifted towards the intensification of the sympathetic part (SP) of the ANS during days of GMSs (K=5-7) with statistical significance p-values: HR (heart rate, p= 0.001), SDNN (Standard deviation of all Normal to Normal intervals, p= 0.0001), RMSSD (The square root of the arithmetical mean of the sum of the squares of differences between adjacent NN intervals, p= 0.0001). In comparison with conditions during GMSs compensation mode (K= 0, B= 0-5nT), the ANS balance was observed to shift during exposure to simulated GMSs with intensities in the range of natural GMSs (K= 7, B= 200nT). However, the initial values of the ANS resulted in different dynamics in its variation depending of GMA level. In the case of initial balanced regulation type (HR > 80) significant intensification of SP was observed with p-values: HR (p= 0.0001), SDNN (p= 0.047), RMSSD (p= 0.28), LF/HF (p=0.03), SI (p= 0.02); while in the case of initial parasympathetic regulation type (HR < 80), an insignificant shift to the intensification of the parasympathetic part (PP) was observed. Conclusions: The results indicate an intensification of SP as a stress reaction of the human organism when it is exposed to high level of GMA in both natural and simulated conditions.

Keywords: autonomic nervous system, device of magneto compensation/simulation, geomagnetic storms, heart rate variability

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Authors: Ethan Shafer, Timothy Graziano

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This research seeks to answer whether first-year courses at institutions of higher learning can impact STEM major selection. Unlike many universities, an entry-level technology course (often referred to as CS0) is required for all United States Military Academy (USMA) students–regardless of major–in their first year of attendance. Students at the academy choose their major at the end of their first year of studies. Through student responses to a multi-semester survey, this paper identifies a number of factors that potentially influence STEM major selection. Student demographic data, pre-existing exposure and access to technology, perceptions of STEM subjects, and initial desire for a STEM major are captured before and after taking a CS0 course. An analysis of factors that contribute to student perception of STEM and major selection are presented. This work provides recommendations and suggestions for institutions currently providing or looking to provide CS0-like courses to their students.

Keywords: education, STEM, pedagogy, digital literacy

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Authors: Gyoutae Park, Woosuk Kim, Sangguk Ahn, Seungmo Kim, Minjun Kim, Jinhan Lee, Youngdo Jo, Jongsam Moon, Hiesik Kim

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In this research, we designed a remote system to test parameters of gas detectors such as gas concentration and initial response time. This testing system is available to measure two gas instruments simultaneously. First of all, we assembled an experimental jig with a square structure. Those parts are included with a glass flask, two high-quality cameras, and two Ethernet modems for transmitting data. This remote gas detector testing system extracts numerals from videos with continually various gas concentrations while LCDs show photographs from cameras. Extracted numeral data are received to a laptop computer through Ethernet modem. And then, the numerical data with gas concentrations and the measured initial response speeds are recorded and graphed. Our remote testing system will be diversely applied on gas detector’s test and will be certificated in domestic and international countries.

Keywords: gas leak detector, inspection instrument, extracting numerals, concentration

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Authors: S. Alireza Mirghasemi, Javad Parvizi, Narges R. Gabaran, Shervin Rashidinia, Mahdi M. Bijanabadi, Dariush G. Savadkoohi

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Background: The anterior cruciate ligament is one of the most frequent ligament to be disrupted. Surgical reconstruction of the anterior cruciate ligament is a common practice to treat the disability or chronic instability of the knee. Several factors associated with success or failure of the ACL reconstruction including preoperative laxity of the knee, selection of the graft material, surgical technique, graft tension, and postoperative rehabilitation. We aimed to examine the biomechanical properties of any graft type and initial graft tensioning during ACL reconstruction using 3-dimensional computational finite element simulation. Methods: In this paper, 3-dimensional model of the knee was constructed to investigate the effect of graft tensioning on the knee joint biomechanics. Four different grafts were compared: 1) Bone-patellar tendon-bone graft (BPTB) 2) Hamstring tendon 3) BPTB and a band of gracilis4) Hamstring and a band of gracilis. The initial graft tension was set as “0, 20, 40, or 60N”. The anterior loading was set to 134 N. Findings: The resulting stress pattern and deflection in any of these models were compared to that of the intact knee. The obtained results showed that the combination of a band of gracilis with the former graft (BPTB or Hamstring) increases the structural stiffness of the knee. Conclusion: Required pretension during surgery decreases significantly by adding a band of gracilis to the proper graft.

Keywords: ACL reconstruction, deflection, finite element simulation, stress pattern

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Authors: F. Ainlhout, S. Boutaleb, M. C. Diaz-Barradas, M. Zunzunegui

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Argania spinosa is an endemic tree of the southwest of Morocco, occupying 828,000 Ha, distributed mainly between Mediterranean vegetation and the desert. This tree can grow in extremely arid regions in Morocco, where annual rainfall ranges between 100-300 mm where no other tree species can live. It has been designated as a UNESCO Biosphere reserve since 1998. Argania tree is of great importance in human and animal feeding of rural population as well as for oil production, it is considered as a multi-usage tree. Admine forest located in the suburbs of Agadir city, 5 km inland, was selected to conduct this work. The aim of the study was to investigate the temporal variation in root-zone moisture dynamic in response to variation in climatic conditions and vegetation water uptake, using a geophysical technique called Electrical resistivity imaging (ERI). This technique discriminates resistive woody roots, dry and moisture soil. Time-dependent measurements (from April till July) of resistivity sections were performed along the surface transect (94 m Length) at 2 m fixed electrode spacing. Transect included eight Argan trees. The interactions between the tree and soil moisture were estimated by following the tree water status variations accompanying the soil moisture deficit. For that purpose we measured midday leaf water potential and relative water content during each sampling day, and for the eight trees. The first results showed that ERI can be used to accurately quantify the spatiotemporal distribution of root-zone moisture content and woody root. The section obtained shows three different layers: middle conductive one (moistured); a moderately resistive layer corresponding to relatively dry soil (calcareous formation with intercalation of marly strata) on top, this layer is interspersed by very resistant layer corresponding to woody roots. Below the conductive layer, we find the moderately resistive layer. We note that throughout the experiment, there was a continuous decrease in soil moisture at the different layers. With the ERI, we can clearly estimate the depth of the woody roots, which does not exceed 4 meters. In previous work on the same species, analyzing the δ18O in water of xylem and in the range of possible water sources, we argued that rain is the main water source in winter and spring, but not in summer, trees are not exploiting deep water from the aquifer as the popular assessment, instead of this they are using soil water at few meter depth. The results of the present work confirm the idea that the roots of Argania spinosa are not growing very deep.

Keywords: Argania spinosa, electrical resistivity imaging, root system, soil moisture

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Authors: Hasan Basaran, Emre Unal

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Formation flying of satellites is a mission that involves a relative position keeping of different satellites in the constellation. In this study, different control algorithms are compared with one another in terms of ΔV, velocity increment, and tracking error. Various control methods, covering continuous and impulsive approaches are implemented and tested for satellites flying in low Earth orbit. Feedback linearization, sliding mode control, and model predictive control are designed and compared with an impulsive feedback law, which is based on mean orbital elements. Feedback linearization and sliding mode control approaches have identical mathematical models that include second order Earth oblateness effects. The model predictive control, on the other hand, does not include any perturbations and assumes circular chief orbit. The comparison is done with 4 different initial errors and achieved with velocity increment, root mean square error, maximum steady state error, and settling time. It was observed that impulsive law consumed the least ΔV, while produced the highest maximum error in the steady state. The continuous control laws, however, consumed higher velocity increments and produced lower amounts of tracking errors. Finally, the inversely proportional relationship between tracking error and velocity increment was established.

Keywords: chief-deputy satellites, feedback linearization, follower-leader satellites, formation flight, fuel consumption, model predictive control, rendezvous, sliding mode

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Authors: M. Emami, R. Tarighi, R. Goodarzi

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Maximal radar wave absorbing cannot be achieved by shaping alone. We have to focus on the parameters of absorbing materials such as permittivity, permeability, and thickness so that best absorbing according to our necessity can happen. The real and imaginary parts of the relative complex permittivity (ε_r' and ε_r") and permeability (µ_r' and µ_r") were obtained by simulation. The microwave absorbing property of carbon and Ni(C) is simulated in this study by MATLAB software; the simulation was in the frequency range between 2 to 12 GHz for carbon black (C), and carbon coated nickel (Ni(C)) with different thicknesses. In fact, we draw reflection loss (RL) for C and Ni-C via frequency. We have compared their absorption for 3-mm thickness and predicted for other thicknesses by using of electromagnetic wave transmission theory. The results showed that reflection loss position changes in low frequency with increasing of thickness. We found out that, in all cases, using nanocomposites as absorbance cannot get better results relative to pure nanoparticles. The frequency where absorption is maximum can determine the best choice between nanocomposites and pure nanoparticles. Also, we could find an optimal thickness for long wavelength absorbing in order to utilize them in protecting shields and covering.

Keywords: absorbing, carbon, carbon nickel, frequency, thicknesses

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Authors: R. Abd-Rahman, M. M. Isa, H. H. Goh

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A compound parabolic concentrator (CPC) is a well known non-imaging concentrator that will concentrate the solar radiation onto receiver (PV cell). One of disadvantage of CPC is has tall and narrow height compared to its diameter entry aperture area. Therefore, for economic reason, a truncation had been done by removed from the top of the full height CPC. This is also will lead to the decreases of concentration ratio but it will be negligible. In this paper, the flux distribution of untruncated and truncated 2-D hollow compound parabolic trough concentrator (hCPTC) design is presented. The untruncated design has initial height, H=193.4mm with concentration ratio, C_(2-D)=4. This paper presents the optical simulation of compound parabolic trough concentrator using ray-tracing software TracePro. Results showed that, after the truncation, the height of CPC reduced 45% from initial height with the geometrical concentration ratio only decrease 10%. Thus, the cost of reflector and material dielectric usage can be saved especially at manufacturing site.

Keywords: compound parabolic trough concentrator, optical modelling, ray-tracing analysis, improved performance

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Authors: Samuel Fekadu A., Esayas Alemayehu B., Bultum Oljira D., Seid Tiku D., Dessalegn Dadi D., Bart Van Der Bruggen A.

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The peroxi-photoelectrocoagulation process was evaluated for the removal of chemical oxygen demand (COD) and color from healthcare wastewater. A 2-level full factorial design with center points was created to investigate the effect of the process parameters, i.e., initial COD, H₂O₂, pH, reaction time and current density. Furthermore, the total energy consumption and average current efficiency in the system were evaluated. Predictive models for % COD, % color removal and energy consumption were obtained. The initial COD and pH were found to be the most significant variables in the reduction of COD and color in peroxi-photoelectrocoagulation process. Hydrogen peroxide only has a significant effect on the treated wastewater when combined with other input variables in the process like pH, reaction time and current density. In the peroxi-photoelectrocoagulation process, current density appears not as a single effect but rather as an interaction effect with H₂O₂ in reducing COD and color. Lower energy expenditure was observed at higher initial COD, shorter reaction time and lower current density. The average current efficiency was found as low as 13 % and as high as 777 %. Overall, the study showed that hybrid electrochemical oxidation can be applied effectively and efficiently for the removal of pollutants from healthcare wastewater.

Keywords: electrochemical oxidation, UV, healthcare pollutants removals, factorial design

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Authors: Weixing Tan

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Production of nutraceuticals from microalgae—a virtually untapped natural phyto-based source of which there are 200,000 to 1,000,000 species—offers a sustainable and healthy alternative to conventionally sourced nutraceuticals for the market. Microalgae can be grown organically using only natural sunlight, water and nutrients at an extremely fast rate, e.g. 10-100 times more efficiently than crops or trees. However, the commercial success of microalgae products at scale remains limited largely due to the lack of economically viable technologies. There are two major microalgae production systems or technologies currently available: 1) the open system as represented by open pond technology and 2) the closed system such as photobioreactors (PBR). Each carries its own unique features and challenges. Although an open system requires a lower initial capital investment relative to a PBR, it conveys many unavoidable drawbacks; for example, much lower productivity, difficulty in contamination control/cleaning, inconsistent product quality, inconvenience in automation, restriction in location selection, and unsuitability for cold areas – all directly linked to the system openness and flat underground design. On the other hand, a PBR system has characteristics almost entirely opposite to the open system, such as higher initial capital investment, better productivity, better contamination and environmental control, wider suitability in different climates, ease in automation, higher and consistent product quality, higher energy demand (particularly if using artificial lights), and variable operational expenses if not automated. Although closed systems like PBRs are not highly competitive yet in current nutraceutical supply market, technological advances can be made, in particular for the PBR technology, to narrow the gap significantly. One example is a readily scalable P2P Microalgae PBR Technology at Grande Prairie Regional College, Canada, developed over 11 years considering return on investment (ROI) for key production processes. The P2P PBR system is approaching economic viability at a pre-commercial stage due to five ROI-integrated major components. They include: (1) optimum use of free sunlight through attenuation (patented); (2) simple, economical, and chemical-free harvesting (patent ready to file); (3) optimum pH- and nutrient-balanced culture medium (published), (4) reliable water and nutrient recycling system (trade secret); and (5) low-cost automated system design (trade secret). These innovations have allowed P2P Microalgae Technology to increase daily yield to 106 g/m2/day of Chlorella vulgaris, which contains 50% proteins and 2-3% omega-3. Based on the current market prices and scale-up factors, this P2P PBR system presents as a promising microalgae technology for market competitive nutraceutical supply.

Keywords: microalgae technology, nutraceuticals, open pond, photobioreactor PBR, return on investment ROI, technological advances

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Authors: Omogoriola Hannah Omoloye

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Fish is a key ingredient on the global menu, a vital factor in the global environment and an important basis for livelihood worldwide1. The length – weight relationships (LWRs) is of great importance in fishery assessment2,3. Its importance is pronounced in estimated the average weight at a given length group4 and in assessing the relative well being of a fish population5. Length and weight measurement in conjunction with age data can give information on the stock composition, age at maturity, life span, mortality, growth and production4,5,6,7. In addition, the data on length and weight can also provides important clues to climatic and environmental changes and the change in human consumption practices8,9. However, the size attained by the individual fish may also vary because of variation in food supply, and these in turn may reflect variation in climatic parameters and in the supply of nutrient or in the degree of competition for food. Environment deterioration, for example, may reduce growth rates and will cause a decrease in the average age of the fish. The condition factor and the relative condition factor10 are the quantitative parameters of the well being state of the fish and reflect recent feeding condition of the fish. It is based on the hypothesis that heavier fish of a given length are in better condition11. This factor varies according to influences of physiological factors, fluctuating according to different stages of the development. Condition factor has been used as an index of growth and feeding intensity12. Condition factor decrease with increase in length 12,13 and also influences the reproductive cycle in fish14. The objective here is to determine the length-weight relationships and condition factor for direct use in fishery assessment and for future comparisons between populations of the same species at different locations. To provide quantitative information on the biology of marine fish species trawl from Nigeria coastal water.

Keywords: condition factor, growth pattern, marine fish species, Nigerian Coastal water

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Authors: S. Perera, T. R. Walsh, M. Solvang

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The structure-property relationships of calcium aluminosilicate (CAS) glass surfaces are of scientific and technological interest regarding dissolution phenomena. Molecular dynamics (MD) simulations can provide atomic-scale insights into the structure and properties of the CAS interfaces in vacuo as the first step to conducting computational dissolution studies on CAS surfaces. However, one limitation to date is that although the bulk properties of CAS glasses have been well studied by MD simulation, corresponding efforts on CAS surface properties are relatively few in number (both theoretical and experimental). Here, a systematic computational protocol to create CAS surfaces in vacuo is developed by evaluating the sensitivity of the resultant surface structure with respect to different factors. Factors such as the relative thickness of the surface layer, the relative thickness of the bulk region, the cooling rate, and the annealing schedule (time and temperature) are explored. Structural features such as ring size distribution, defect concentrations (five-coordinated aluminium (AlV), non-bridging oxygen (NBO), and tri-cluster oxygen (TBO)), and linkage distribution are identified as significant features in dissolution studies.

Keywords: MD simulation, CAS glasses, surface structure, structure-property, CAS interface

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Authors: Hao-Yuan Tseng, Chuan-Yang Chang, Ying-Hui Chen, Sheng-Che Chen, Chih-Han Chang

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Orthodontic tooth treatment has demonstrated a high success rate in clinical studies. It has been agreed upon that orthodontic tooth movement is based on the ability of surrounding bone and periodontal ligament (PDL) to react to a mechanical stimulus with remodeling processes. However, the mechanism of the tooth movement is still unclear. Recent studies focus on the simple principle compression-tension theory while rare studies directly measure tooth movement. Therefore, tracking tooth movement information during orthodontic treatment is very important in clinical practice. The aim of this study is to investigate the mechanism responses of the tooth movement during the orthodontic treatments. A stereovision system applied to track the tooth movement of the patient with the stamp brackets. The system was established by two cameras with their relative position calibrate. And the orthodontic force measured by 3D printing model with the six-axis load cell to determine the initial force application. The result shows that the stereovision system accuracy revealed the measurement presents a maximum error less than 2%. For the study on patient tracking, the incisor moved about 0.9 mm during 60 days tracking, and half of movement occurred in the first few hours. After removing the orthodontic force in 100 hours, the distance between before and after position incisor tooth decrease 0.5 mm consisted with the release of the phenomenon. Using the stereovision system can accurately locate the three-dimensional position of the teeth and superposition of 3D coordinate system for all the data to integrate the complex tooth movement.

Keywords: orthodontic treatment, tooth movement, stereovision system, long-term tracking

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Authors: Danika Tynes

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Telehealth is a promising advancement in health care, though there are certain conditions under which telehealth has a greater chance of success. This research sought to further the understanding of what conditions compel the success of telehealth adoption at the systems level applying Diffusion of Innovations (DoI) theory (Rogers, 1962). System-level indicators were selected to represent four components of DoI theory (relative advantage, compatibility, complexity, and observability) and regressed on 5 types of telehealth (teleradiology, teledermatology, telepathology, telepsychology, and remote monitoring) using multiple logistic regression. The analyses supported relative advantage and compatibility as the strongest influencers of telehealth adoption, remote monitoring in particular. These findings help to quantitatively clarify the factors influencing the adoption of innovation and advance the ability to make recommendations on the viability of state telehealth adoption. In addition, results indicate when DoI theory is most applicable to the understanding of telehealth diffusion. Ultimately, this research may contribute to more focused allocation of scarce health care resources through consideration of existing state conditions available foster innovation.

Keywords: adoption, diffusion of innovation theory, remote monitoring, system-level indicators

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Authors: Ruhollah Basatnia, Ali Reza Aghababa, Mehrdad Anbarian, Sara Akbari, Mohammad Khazaee

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Introduction: The investigation of brain activity in sports has become a subject of interest for researchers. Several studies have examined the patterns or differences in brain activity during different sports situations. Previous studies have suggested that the pattern of cortical activity may differ between different football positions, such as goalkeepers and other players. This study aims to investigate the differences in electroencephalographic (EEG) activity between the positions of goalkeeper and forward in professional football players. Methods: Fourteen goalkeepers and twelve forwards, all males between 19-28 years old, participated in the study. EEG activity was recorded while participants were sitting with their eyes closed for 5 minutes. The mean relative power of EEG activity for each frequency band was compared between the two groups using independent samples t-test. Findings: The study found significant differences in the relative power of EEG activity between different frequency bands and electrodes. Notably, significant differences were observed in the mean relative power of EEG activity between the two groups for certain frequency bands and electrodes. These findings suggest that EEG activity can serve as a sensory indicator for cognitive and performance differences between goalkeepers and forwards in football players. Discussion: The results of this study suggest that EEG activity can be used to identify cognitive and performance differences between goalkeepers and forwards in football players. However, further research is needed to establish the relationship between EEG activity and actual performance in the field. Future studies should investigate the potential influence of other factors, such as fatigue and stress, on the EEG activity of football players. Additionally, the use of real-time EEG feedback could be explored as a tool for training and performance optimization in football players. Further research is required to fully understand the potential of EEG activity as a sensory indicator for cognitive and performance differences between football player positions and to explore its potential applications for training and performance optimization in football and other sports.

Keywords: football, brain activity, EEG, goalkeepers, forwards

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Authors: Fatima Zahra Mahjoubi, Abderrahim Khalidi, Mohamed Abdennouri, Omar Cherkaoui, Noureddine Barka

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Industrial effluents are one of the major causes of environmental pollution, especially effluents discharged from various dyestuff manufactures, plastic, and paper making industries. These effluents can give rise to certain hazards and environmental problems for their highly colored suspended organic solid. Dye effluents are not only aesthetic pollutants, but coloration of water by the dyes may affect photochemical activities in aquatic systems by reducing light penetration. It has been also reported that several commonly used dyes are carcinogenic and mutagenic for aquatic organisms. Therefore, removing dyes from effluents is of significant importance. Many adsorbent materials have been prepared in the removal of dyes from wastewater, including anionic clay or layered double hydroxyde. The zinc/aluminium (Zn-AlNO₃), magnesium/aluminium (Mg-AlNO₃) and nickel/aluminium (Ni-AlNO₃) layered double hydroxides (LDHs) were successfully synthesized via coprecipitation method. Samples were characterized by XRD, FTIR, TGA/DTA, TEM and pHPZC analysis. XRD patterns showed a basal spacing increase in the order of Zn-AlNO₃ (8.85Å)> Mg-AlNO₃ (7.95Å)> Ni-AlNO₃ (7.82Å). FTIR spectrum confirmed the presence of nitrate anions in the LDHs interlayer. The TEM images indicated that the Zn-AlNO3 presents circular to shaped particles with an average particle size of approximately 30 to 40 nm. Small plates assigned to sheets with hexagonal form were observed in the case of Mg-AlNO₃. Ni-AlNO₃ display nanostructured sphere in diameter between 5 and 10 nm. The LDHs were used as adsorbents for the removal of methyl orange (MO), as a model dye and for the treatment of an effluent generated by a textile factory. Adsorption experiments for MO were carried out as function of solution pH, contact time and initial dye concentration. Maximum adsorption was occurred at acidic solution pH. Kinetic data were tested using pseudo-first-order and pseudo-second-order kinetic models. The best fit was obtained with the pseudo-second-order kinetic model. Equilibrium data were correlated to Langmuir and Freundlich isotherm models. The best conditions for color and COD removal from textile effluent sample were obtained at lower values of pH. Total color removal was obtained with Mg-AlNO₃ and Ni-AlNO₃ LDHs. Reduction of COD to limits authorized by Moroccan standards was obtained with 0.5g/l LDHs dose.

Keywords: chemical oxygen demand, color removal, layered double hydroxides, textile wastewater treatment

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Authors: Watchareeporn Chaimongkol

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In this paper, we compare the statistical measures accuracy of composite forecasting model to estimate automobile customer demand in Thailand. A modified simple exponential smoothing and autoregressive integrate moving average (ARIMA) forecasting model is built to estimate customer demand of passenger cars, instead of using information of historical sales data. Our model takes into account special characteristic of the Thai automobile market such as sales promotion, advertising and publicity, petrol price, and interest rate for loan. We evaluate our forecasting model by comparing forecasts with actual data using six accuracy measurements, mean absolute percentage error (MAPE), geometric mean absolute error (GMAE), symmetric mean absolute percentage error (sMAPE), mean absolute scaled error (MASE), median relative absolute error (MdRAE), and geometric mean relative absolute error (GMRAE).

Keywords: composite forecasting, simple exponential smoothing model, autoregressive integrate moving average model selection, accuracy measurements

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Authors: Abdessalem Abbassi, Ahlem Dakhlaoui, Lota D. Tamini

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This article analyses management of hydropower dams within two different industrial structures: monopolistic and oligopolistic; when hydroelectricity producers are risk averse and face demand uncertainty. In each type of market structure we determine the water release path in closed-loop equilibrium. We show how a monopoly can manage its hydropower dams by additional pumping or storage depending on the relative abundance of water between different regions to smooth the effect of uncertainty on electricity prices. In the oligopolistic case with symmetric rates of risk aversion, we determine the conditions under which the relative scarcity (abundance) of water in the dam of a hydroelectric operator can favor additional strategic pumping (storage) in its competitor’s dams. When there is asymmetry of the risk aversion coefficient, the firm’s hydroelectricity production increases as its competitor’s risk aversion increases, if and only if the average recharge speed of the competitor’s dam exceeds a certain threshold, which is an increasing function of its average water inflows.

Keywords: asymmetric risk aversion, closed-loop Cournot competition, electricity wholesale market, hydropower dams

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Authors: Hanjong Kim, Changwan Han, Seonghun Park

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Heat exchanger manifolds in aircraft play an important role in evenly distributing the fluid entering through the inlet to the heat transfer unit. In order to achieve this requirement, the manifold should be designed to have a light weight by withstanding high internal pressure. Therefore, this study aims at minimizing the weight of the heat exchanger manifold through topology optimization. For topology optimization, the initial design space was created with the inner surface extracted from the currently used manifold model and with the outer surface having a dimension of 243.42 mm of X 74.09 mm X 65 mm. This design space solid model was transformed into a finite element model with a maximum tetrahedron mesh size of 2 mm using ANSYS Workbench. Then, topology optimization was performed under the boundary conditions of an internal pressure of 5.5 MPa and the fixed support for rectangular inlet boundaries by SIMULIA TOSCA. This topology optimization produced the minimized finial volume of the manifold (i.e., 7.3% of the initial volume) based on the given constraints (i.e., 6% of the initial volume) and the objective function (i.e., maximizing manifold stiffness). Weight of the optimized model was 6.7% lighter than the currently used manifold, but after smoothing the topology optimized model, this difference would be bigger. The current optimized model has uneven thickness and skeleton-shaped outer surface to reduce stress concentration. We are currently simplifying the optimized model shape with spline interpolations by reflecting the design characteristics in thickness and skeletal structures from the optimized model. This simplified model will be validated again by calculating both stress distributions and weight reduction and then the validated model will be manufactured using 3D printing processes.

Keywords: topology optimization, manifold, heat exchanger, 3D printing

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Authors: Nazanin Amanat, Alison Tayler, Steve Whyard

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While chemical insecticides effectively control many insect pests, they also harm many non-target species. Double-stranded RNA (dsRNA) pesticides, in contrast, can be designed to target unique gene sequences and thus act in a species-specific manner. DsRNA insecticides do not, however, work equally well for all insects, and for some species that are considered refractory to dsRNA, a primary factor affecting efficacy is the relative ease by which dsRNA can enter a target cell’s cytoplasm. In this study, we are examining how different structured dsRNAs (linear, hairpin, and paperclip) can enter mosquito and lepidopteran cells, as they represent dsRNA-sensitive and refractory species, respectively. To determine how the dsRNAs enter the cells, we are using chemical inhibitors and RNA interference (RNAi)-mediated knockdown of key proteins associated with different endocytosis processes. Understanding how different dsRNAs enter cells will ultimately help in the design of molecules that overcome refractoriness to RNAi or develop resistance to dsRNA-based insecticides. To date, we have conducted chemical inhibitor experiments on both cell lines and have evidence that linear dsRNAs enter the cells using clathrin-mediated endocytosis, while the paperclip dsRNAs (pcRNAs) can enter both species’ cells in a clathrin-independent manner to induce RNAi. An alternative uptake mechanism for the pcRNAs has been tentatively identified, and the outcomes of our RNAi-mediated knockdown experiments, which should provide corroborative evidence of our initial findings, will be discussed.

Keywords: dsRNA, RNAi, uptake, insecticides, dipteran, lepidopteran

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Authors: Ahmed M. Ashteyat

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Artificial Neural Network (ANN) models have been widely used in material modeling, inter-correlations, as well as behavior and trend predictions when the nonlinear relationship between system parameters cannot be quantified explicitly and mathematically. In this paper, ANN was used to predict the residual modulus of elasticity (RME) of self compacted concrete (SCC) damaged by heat. The ANN model was built, trained, tested and validated using a total of 112 experimental data sets, gathered from available literature. The data used in model development included temperature, relative humidity conditions, mix proportions, filler types, and fiber type. The result of ANN training, testing, and validation indicated that the RME of SCC, exposed to different temperature and relative humidity levels, could be predicted accurately with ANN techniques. The reliability between the predicated outputs and the actual experimental data was 99%. This show that ANN has strong potential as a feasible tool for predicting residual elastic modulus of SCC damaged by heat within the range of input parameter. The ANN model could be used to estimate the RME of SCC, as a rapid inexpensive substitute for the much more complicated and time consuming direct measurement of the RME of SCC.

Keywords: residual modulus of elasticity, artificial neural networks, self compacted-concrete, material modeling

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Authors: Mustafa Jaradat

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Reasonable energy saving for dehumidification is feasible with the use of desiccants. Desiccants are able to lower the humidity content in the air irrespective of the dew point temperature. In this paper, a tube bundle liquid desiccant air conditioner was experimentally designed and evaluated using lithium chloride as a desiccant. Several experiments were conducted to evaluate the influence of the inlet parameters on the dehumidifier performance. The results show a reduction in the relative humidity in the range of 17 to 46%, and the change in the humidity ratio was between 1.5 to 4.7 g/kg, depending on the inlet conditions. A water removal rate in the range between 0.54 and 1.67 kg/h was observed. The effects of air relative humidity and the desiccant flow rate on the dehumidifier’s performance were investigated. It was found that the moisture removal rate remarkably increased with increasing desiccant flow rate and air inlet humidity ratio. The dehumidifier effectiveness increased sharply with increasing desiccant flow rate. Also, it was found that the dehumidifier effectiveness slightly decreased with air humidity ratio.

Keywords: air conditioning, dehumidification, desiccant, lithium chloride, tube bundle

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Authors: Aparna Lal, Ashwin Swaminathan, Teisa Holani

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Background: Clostridium difficile infections (CDIs) have been on the rise globally. In Australia, rates of CDI in all States and Territories have increased significantly since mid-2011. Identifying risk factors for CDI in the community can help inform targeted interventions to reduce infection. Methods: We examine the role of neighbourhood socio-economic status, demography, testing practices and the number of residential aged care facilities on spatial patterns in CDI incidence in the Australian Capital Territory. Data on all tests conducted for CDI were obtained from ACT Pathology by postcode for the period 1st January 2004 through 31 December 2014. Distribution of age groups and the neighbourhood Index of Relative Socio-economic Advantage Disadvantage (IRSAD) were obtained from the Australian Bureau of Statistics 2011 National Census data. A Bayesian spatial conditional autoregressive model was fitted at the postcode level to quantify the relationship between CDI and socio-demographic factors. To identify CDI hotspots, exceedance probabilities were set at a threshold of twice the estimated relative risk. Results: CDI showed a positive spatial association with the number of tests (RR=1.01, 95% CI 1.00, 1.02) and the resident population over 65 years (RR=1.00, 95% CI 1.00, 1.01). The standardized index of relative socio-economic advantage disadvantage (IRSAD) was significantly negatively associated with CDI (RR=0.74, 95% CI 0.56, 0.94). We identified three postcodes with high probability (0.8-1.0) of excess risk. Conclusions: Here, we demonstrate geographic variations in CDI in the ACT with a positive association of CDI with socioeconomic disadvantage and identify areas with a high probability of elevated risk compared with surrounding communities. These findings highlight community-based risk factors for CDI.

Keywords: spatial, socio-demographic, infection, Clostridium difficile

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Authors: I. Mukherjee, J. Ghose, T. Chakraborty, S. Chaudhury, R. Majumder

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India is the second most populated nation in the world. With the Indian population hitting the 1.26 billion mark in the year 2014, there has been an unprecedented rise in power and energy requirements throughout the nation. This mammoth demand for energy, both at the industrial as well as at the domestic household level, as well as the increase in the usage of automobiles has led to a corresponding increase in the total tonnage of fuels being burnt every year. This, in turn, has led to an increase in the concentration of atmospheric pollutants over the years with enhanced particulate concentrations being reported for different parts of the country. Considering the adverseness of the particulates, the paper analyses the role of the particulates on the air quality of four major congested cities of the country namely, Kolkata (22034’ N, 88024’ E), Delhi (28038’N , 77012’ E), Bangalore (12058’ N , 77038’E) and Mumbai (18.9750° N, 72.8258° E) over a period of four years from 2006-2009. The fractional contribution of the finer fractions to the coarser one has been considered in the study in addition to the relative occurrences of the particulate fractions with respect to the other gaseous pollutants such as sulphur dioxide (SO2) and nitrogen oxides (NOX).

Keywords: air quality, particulates, yearly variation, relative occurrence, SO2, NOX

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