Search results for: generalized differential quadrature method

Authors: Alireza Alesaadi

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Reliability analysis is a powerful method for determining the weak points of the electrical networks. In designing of electrical network, it is tried to design the most reliable network with minimal system shutting down, but it is usually associated with increasing the cost. In this paper, using adaptive genetic algorithm, a method was presented that provides the most reliable system with a certain economical cost. Finally, the proposed method is applied to a sample network and results will be analyzed.

Keywords: reliability, adaptive genetic algorithm, electrical network, communication engineering

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Authors: Ming Yi Hsu, Hui Jung Chao

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The anxiety and depression adolescents in Taiwan experience can cause suicide attempts and result in unfortunate deaths. An effective method for relieving anxiety and depression is brisk walking; a moderate and low intensity aerobic exercise, which uses large muscle groups rhythmically. The research purpose was to investigate the effects of a 12-week, school-based, brisk-walking program in decreasing anxiety and depression, and in improving self-concept among high school students living in central Taiwan. A quasi-experiment using the time series design (T1 T2 X T3 T4) was conducted. The Beck Youth Inventories 2 (BYI-II) Chinese version was given four times: the first time T1 was in the 4th week prior to intervention, T2 was in the intervention week, T3 was in the 6th week after the start of the intervention period and T4 was in the 12th week post intervention. The baseline phase of the time series constituted T1 and T2. The intervention phase constituted T2, T3, and T4. The amounts of brisk walking were recorded by self-report The Generalized Estimating Equation (GEE) was used to examine the effects of brisk walking on anxiety, depression, and self-concept. The independent t-test was used to compare mean scores on three dependent variables between brisk walking over and less than 90-minutes per week. Findings revealed that levels of anxiety and self-concept had nonsignificant change during the baseline phase, while the level of depression increased significantly. In contrast, the study demonstrated significant decreases in anxiety and depression as well as increases in positive self-concept (p=.001, p<.001, p=.017) during the intervention phase. Furthermore, a subgroup analysis was completed on participants who demonstrated elevated anxiety (23.4%), and depression (29.7%), and below average self-concept (18.6%) at baseline (T2). The subgroup of anxious, depressed, or low self-concept participants who received the brisk-walking intervention demonstrated significant decreases in anxiety and depression, and significant increases in self-concept scores. Participants who engaged in brisk walking over 90 minutes per week reported decreased mean scores on anxiety (t=-2.395, p=.035) and depression (t=-2.142, p=.036) in contrast with those who engaged in brisk-walking time less than 90 minutes per week. Regarding the effects on participants whose anxiety, scores were within the normal range at baseline, there was demonstrated significant decrease in the level of anxiety when they increased their time on brisk walking before each term examination. Overall, the brisk-walking program was effective and feasible to promote adolescents’ mental health by decreasing anxiety and depression as well as elevating self-concept. It also helped adolescents from anxiety before term examinations.

Keywords: adolescents, anxiety, depression, self-concept

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Authors: Hidouri Sami, Aguili Taoufik

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We consider fast and accurate solutions of scattering problems by large perfectly conducting objects (PEC) formulated by an optimization of the Method of Auxiliary Sources (MAS). We present various techniques used to reduce the total computational cost of the scattering problem. The first technique is based on replacing the object by an array of finite number of small (PEC) object with the same shape. The second solution reduces the problem on considering only the half of the object.These two solutions are compared to results from the reference bibliography.

Keywords: method of auxiliary sources, scattering, large object, RCS, computational resources

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Authors: Tunjo Perič, Marin Fatović

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In this paper a new methodology for vendor selection and supply quotas determination (VSSQD) is proposed. The problem of VSSQD is solved by the model that combines revised weighting method for determining the objective function coefficients, and a multiple objective linear programming (MOLP) method based on the cooperative game theory for VSSQD. The criteria used for VSSQD are: (1) purchase costs and (2) product quality supplied by individual vendors. The proposed methodology is tested on the example of flour purchase for a bakery with two decision makers.

Keywords: cooperative game theory, multiple objective linear programming, revised weighting method, vendor selection

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Authors: Han Run-Sheng, Li Wen-Yao, Wang Feng, Liu Fei, Qiu Wen-Long, Lei Li

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Accurately positioning detection of concealed deposits or ore-bodies is one of the difficult problems in mineral exploration field. Theory calculation and exploration practices for tunnel gravity indicate that 3D high-precision Tunnel Gravity Exploration Method (TGEM) can find concealed high-density three-dimensional ore-bodies in the depth. The ore-finding breakthroughs at the depth of the Zhaotong Maoping carbonate-hosted Zn–Pb–(Ag–Ge) deposit in Northeastern Yunnan have proved that the exploration method in combination with MEAHFZ method is effective to detect concealed high-density ore-bodies. TGEM may overcome anomalous ambiguity of other geophysical methods for 3D positioning of concealed ore-bodies.

Keywords: 3D tunnel gravity exploration method, concealed high-density Ore-bodies, Zn–Pb–(Ag–Ge) deposit, Zaotong mapping, Northeastern Yunnan

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Authors: El Asnaoui Khalid, Chawki Youness, Aksasse Brahim, Ouanan Mohammed

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In these recent decades, the important and fast growth in the development and demand of multimedia products is contributing to an insufficient in the bandwidth of device and network storage memory. Consequently, the theory of data compression becomes more significant for reducing the data redundancy in order to save more transfer and storage of data. In this context, this paper addresses the problem of the lossless and the near-lossless compression of images. This proposed method is based on Block SVD Power Method that overcomes the disadvantages of Matlab's SVD function. The experimental results show that the proposed algorithm has a better compression performance compared with the existing compression algorithms that use the Matlab's SVD function. In addition, the proposed approach is simple and can provide different degrees of error resilience, which gives, in a short execution time, a better image compression.

Keywords: image compression, SVD, block SVD power method, lossless compression, near lossless

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Authors: Olga V. Korotkaya

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This article is devoted to an important problem of calculation of deflected mode of the combustion chamber and the nozzle end of a new liquid-propellant rocket cruise engine. A special attention is given to the methodology of calculation. Three operating modes are considered. The analysis has been conducted in ANSYS software. The methods of conducted research are mathematical modelling, substructure method, cyclic symmetry, and finite element method. The calculation has been carried out to order of S. P. Korolev Rocket and Space Corporation «Energia». The main results are practical. Proposed methodology and created models would be able to use for a wide range of strength problems.

Keywords: combustion chamber, cyclic symmetry, finite element method, liquid-propellant rocket engine, nozzle end, substructure

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Authors: S. R. Dehghani, Y. S. Muzychka, G. F. Naterer

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The ice accretion of salt water on cold substrates creates brine-spongy ice. This type of ice is a mixture of pure ice and liquid brine. A real case of creation of this type of ice is superstructure icing which occurs on marine vessels and offshore structures in cold and harsh conditions. Transient heat transfer through this medium causes phase changes between brine pockets and pure ice. Salt rejection during the process of transient heat conduction increases the salinity of brine pockets to reach a local equilibrium state. In this process the only effect of passing heat through the medium is not changing the sensible heat of the ice and brine pockets; latent heat plays an important role and affects the mechanism of heat transfer. In this study, a new analytical model for evaluating heat transfer through brine-spongy ice is suggested. This model considers heat transfer and partial solidification and melting together. Properties of brine-spongy ice are obtained using properties of liquid brine and pure ice. A numerical solution using Method of Lines discretizes the medium to reach a set of ordinary differential equations. Boundary conditions are chosen using one of the applicable cases of this type of ice; one side is considered as a thermally isolated surface, and the other side is assumed to be suddenly affected by a constant temperature boundary. All cases are evaluated in temperatures between -20 C and the freezing point of brine-spongy ice. Solutions are conducted using different salinities from 5 to 60 ppt. Time steps and space intervals are chosen properly to maintain the most stable and fast solution. Variation of temperature, volume fraction of brine and brine salinity versus time are the most important outputs of this study. Results show that transient heat conduction through brine-spongy ice can create a various range of salinity of brine pockets from the initial salinity to that of 180 ppt. The rate of variation of temperature is found to be slower for high salinity cases. The maximum rate of heat transfer occurs at the start of the simulation. This rate decreases as time passes. Brine pockets are smaller at portions closer to the colder side than that of the warmer side. A the start of the solution, the numerical solution tends to increase instabilities. This is because of sharp variation of temperature at the start of the process. Changing the intervals improves the unstable situation. The analytical model using a numerical scheme is capable of predicting thermal behavior of brine spongy ice. This model and numerical solutions are important for modeling the process of freezing of salt water and ice accretion on cold structures.

Keywords: method of lines, brine-spongy ice, heat conduction, salt water

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Authors: Vinodhini Elangovan, Jen Heng Pek

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Background: An ectopic pregnancy is defined as any pregnancy implanted outside of the endometrial cavity. Cornual pregnancy, a rare variety of ectopic pregnancies, is seen in about 2-4% of ectopic pregnancies. It develops in the interstitial portion of the fallopian tube and invades through the uterine wall. This case describes a third-trimester cornual pregnancy that resulted in a uterine rupture. Case: A 38-year old Chinese lady was brought to the Emergency Department (ED) as a standby case for hypotension. She was 30+6 weeks pregnant (Gravida 3, Parous 1). Her past obstetric history included a live birth delivered via lower segment Caesarean section due to non-reassuring fetal status in 2002 and a miscarriage in 2012. She developed generalized abdominal pain. There was no per vaginal bleeding or leaking liquor. There was also no fever, nausea, vomiting, constipation, diarrhea, or urinary symptoms. On arrival in the ED, she was pale, diaphoretic, and lethargic. She had generalized tenderness with guarding and rebound over her abdomen. Point of care ultrasound was performed and showed a large amount of intra-abdominal free fluid, and the fetal heart rate was 170 beats per minute. The point of care hemoglobin was 7.1 g/dL, and lactate was 6.8 mmol/L. The patient’s blood pressure dropped precipitously to 50/36 mmHg, and her heart rate went up to 141 beats per minute. The clinical impression was profound shock secondary to uterine rupture. Intra-operatively, there was extensive haemoperitoneum, and the fetus was seen in the abdominal cavity. The fetus was delivered immediately and handed to the neonatal team. On exploration of the uterus, the point of rupture was at the left cornual region where the placenta was attached to. Discussion: Cornual pregnancies are difficult to diagnose pre-operatively with low ultrasonographic sensitivity and hence are commonly confused with normal intrauterine pregnancies. They pose a higher risk of rupture and hemorrhage compared to other types of ectopic pregnancies. In very rare circumstances, interstitial pregnancies can result in a viable fetus. Uterine rupture resulting in hemorrhagic shock is a true obstetric emergency that can result in significant morbidity and mortality for the patient and the fetus, and early diagnosis in the emergency department is crucial. The patient in this case presented with known risk factors of multiparity, advanced maternal age, and previous lower segment cesarean section, which increased the suspicion of uterine rupture. Ultrasound assessment may be beneficial to any patient who presents with symptoms and a history of uterine surgery to assess the possibility of uterine dehiscence or rupture. Management of a patient suspected of uterine rupture should be systematic in the emergency department and follow an ABC approach. Conclusion: This case demonstrates the importance for an emergency physician to maintain the suspicion for ectopic pregnancy even at advanced gestational ages. It also highlights how even though all emergency physicians may not be qualified to do a detailed pelvic ultrasound, it is essential for them to be competent with a point of care ultrasound to make a prompt diagnosis of conditions such as uterine rupture.

Keywords: cornual ectopic , ectopic pregnancy, emergency medicine, obstetric emergencies

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Authors: İsmail İnce

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The aim of this study is to determine index and mechanical properties of pyroclastic rock in a practical way by means of electrical resistivity method. For this purpose, electrical resistivity, uniaxial compressive strength, point load strength, P-wave velocity, density and porosity values of 10 different pyroclastic rocks were measured in the laboratory. A simple regression analysis was made among the index-mechanical properties of the samples compatible with electrical resistivity values. A strong exponentially relation was found between index-mechanical properties and electrical resistivity values. The electrical resistivity method can be used to assess the engineering properties of the rock from which it is difficult to obtain regular shaped samples as a non-destructive method.

Keywords: electrical resistivity, index-mechanical properties, pyroclastic rocks, regression analysis

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Authors: Y. H. Wu, Ji-Yuan Lin, Yu-Ming Liou

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This study aims to set up the landslide susceptibility map of County Route 89 at Ren-Ai Township in Nantou County using the Instability Index Method and Logistic regression. Seven susceptibility factors including Slope Angle, Aspect, Elevation, Distance to fold, Distance to River, Distance to Road and Accumulated Rainfall were obtained by GIS based on the Typhoon Toraji landslide area identified by Industrial Technology Research Institute in 2001. To calculate the landslide percentage of each factor and acquire the weight and grade the grid by means of Instability Index Method. In this study, landslide susceptibility can be classified into four grades: high, medium high, medium low and low, in order to determine the advantages and disadvantages of the two models. The precision of this model is verified by classification error matrix and SRC curve. These results suggest that the logistic regression model is a preferred method than instability index in the assessment of landslide susceptibility. It is suitable for the landslide prediction and precaution in this area in the future.

Keywords: instability index method, logistic regression, landslide susceptibility, SRC curve

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Authors: Kelsey Kimball

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Generalized anxiety disorder (GAD) is a common mental health illness affecting approximately 10% of the perinatal population. Research examining cognitive behavioral therapy in this population has only recently become more prevalent though exploring this subject is long overdue. This research examines the impact of cognitive behavioral therapy (CBT) on GAD during the perinatal period. The aim of this project was to identify the most effective way to manage GAD during the perinatal period to provide clinicians with evidence-based methods of caring for this population’s mental health. The research was conducted using several databases to identify ten primary research articles involving anxiety management. A critique and a systematic review of the literature was done. The results of the systematic literature review suggested that CBT had a significant positive impact on perinatal anxiety. Three main themes were derived from the literature: CBT for managing GAD in the general population, CBT for managing GAD in the perinatal population, and CBT’s effect on worry and problematic behaviors in both populations. Nurse practitioners are central in improving access to and treatment of perinatal anxiety disorders.

Keywords: anxiety, cognitive behavioral therapy, nurse practitioner, perinatal

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Authors: Boris Djartov, Sanaz Mostaghim

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This paper presents a number-based dominance method. The main idea is how to fragment the many attributes of the problem into subsets suitable for the well-established concept of Pareto dominance. Although other similar methods can be found in the literature, they focus on comparing the solutions one objective at a time, while the focus of this method is to compare entire subsets of the objective vector. Given the nature of the method, it is computationally costlier than other methods and thus, it is geared more towards selecting an option from a finite set of alternatives, where each solution is defined by multiple objectives. The need for this method was motivated by dynamic alternate airport selection (DAAS). In DAAS, pilots, while en route to their destination, can find themselves in a situation where they need to select a new landing airport. In such a predicament, they need to consider multiple alternatives with many different characteristics, such as wind conditions, available landing distance, the fuel needed to reach it, etc. Hence, this method is primarily aimed at human decision-makers. Many methods within the field of multi-objective and many-objective decision-making rely on the decision maker to initially provide the algorithm with preference points and weight vectors; however, this method aims to omit this very difficult step, especially when the number of objectives is so large. The proposed method will be compared to Favour (1 − k)-Dom and L-dominance (LD) methods. The test will be conducted using well-established test problems from the literature, such as the DTLZ problems. The proposed method is expected to outperform the currently available methods in the literature and hopefully provide future decision-makers and pilots with support when dealing with many-objective optimization problems.

Keywords: multi-objective decision-making, many-objective decision-making, multi-objective optimization, many-objective optimization

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Authors: Wenjiang Deng, Tian Mou, Yudi Pawitan, Trung Nghia Vu

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Estimation of isoform-level gene expression from RNA-seq data depends on simplifying assumptions, such as uniform reads distribution, that are easily violated in real data. Such violations typically lead to biased estimates. Most existing methods provide a bias correction step(s), which is based on biological considerations, such as GC content–and applied in single samples separately. The main problem is that not all biases are known. For example, new technologies such as single-cell RNA-seq (scRNA-seq) may introduce new sources of bias not seen in bulk-cell data. This study introduces a method called XAEM based on a more flexible and robust statistical model. Existing methods are essentially based on a linear model Xβ, where the design matrix X is known and derived based on the simplifying assumptions. In contrast, XAEM considers Xβ as a bilinear model with both X and β unknown. Joint estimation of X and β is made possible by simultaneous analysis of multi-sample RNA-seq data. Compared to existing methods, XAEM automatically performs empirical correction of potentially unknown biases. XAEM implements an alternating expectation-maximization (AEM) algorithm, alternating between estimation of X and β. For speed XAEM utilizes quasi-mapping for read alignment, thus leading to a fast algorithm. Overall XAEM performs favorably compared to other recent advanced methods. For simulated datasets, XAEM obtains higher accuracy for multiple-isoform genes, particularly for paralogs. In a differential-expression analysis of a real scRNA-seq dataset, XAEM achieves substantially greater rediscovery rates in an independent validation set.

Keywords: alternating EM algorithm, bias correction, bilinear model, gene expression, RNA-seq

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Authors: B. Bouadjemi, S. Bentata, T. Lantri, A. Abbad, W. Benstaali, A. Zitouni, S. Cherid

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We investigate the electronic structure, magnetic and optical properties of the orthorhombic NdMnO3 through density-functional-theory (DFT) calculations using both generalized gradient approximation GGA and GGA+U approaches, the exchange and correlation effects are taken into account by an orbital independent modified Becke Johnson (MBJ). The predicted band gaps using the MBJ exchange approximation show a significant improvement over previous theoretical work with the common GGA and GGA+U very closer to the experimental results. Band gap dependent optical parameters like dielectric constant, index of refraction, absorption coefficient, reflectivity and conductivity are calculated and analyzed. We find that when using MBJ we have obtained better results for band gap of NdMnO3 than in the case of GGA and GGA+U. The values of band gap founded in this work by MBJ are in a very good agreement with corresponding experimental values compared to other calculations. This comprehensive theoretical study of the optoelectronic properties predicts that this material can be effectively used in optical devices.

Keywords: DFT, optical properties, absorption coefficient, strong correlation, MBJ, orthorhombic NdMnO3, optoelectronic

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Authors: Ranjith Maniyeri, Ahamed C. Saleel

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Two-dimensional fluid flow over a stationary circular cylinder is one of the bench mark problem in the field of fluid-structure interaction in computational fluid dynamics (CFD). Motivated by this, in the present work, a two-dimensional computational model is developed using an improved version of immersed boundary method which combines the feedback forcing scheme of the virtual boundary method with Peskin’s regularized delta function approach. Lagrangian coordinates are used to represent the cylinder and Eulerian coordinates are used to describe the fluid flow. A two-dimensional Dirac delta function is used to transfer the quantities between the sold to fluid domain. Further, continuity and momentum equations governing the fluid flow are solved using fractional step based finite volume method on a staggered Cartesian grid system. The developed code is validated by comparing the values of drag coefficient obtained for different Reynolds numbers with that of other researcher’s results. Also, through numerical simulations for different Reynolds numbers flow behavior is well captured. The stability analysis of the improved version of immersed boundary method is tested for different values of feedback forcing coefficients.

Keywords: Feedback Forcing Scheme, Finite Volume Method, Immersed Boundary Method, Navier-Stokes Equations

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Authors: Krasimir Ivanov, Elitsa Kolentsova, Nguyen Nguyen, Alexander Peltekov, Violina Angelova

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The nanosized zinc hydroxide nitrate has been recently estimated as perspective foliar fertilizer, which has improved zinc solubility, but low phytotoxicity, in comparison with ZnO and other Zn containing compounds. The main problem is obtaining of stable particles with dimensions less than 100 nm. This work studies the effect of preparation conditions on the chemical compositions and particle size of the zinc hydroxide nitrates, prepared by precipitation. Zn(NO3)2.6H2O and NaOH with concentrations, ranged from 0.2 to 3.2M and the initial OH/Zn ratio from 0.5 to 1.6 were used at temperatures from 20 to 60 °C. All samples were characterized in detail by X-ray diffraction, scanning electron microscopy, differential thermal analysis and ICP. Stability and distribution of the zinc hydroxide nitrate particles were estimated too.

Keywords: zinc hydroxide nitrate, nanoparticles, preparation, foliar fertilizer

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Authors: Jiri F. Urbanek, Jiri Barta, Oldrich Svoboda, Jiri J. Urbanek

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The organizations of European and Czech critical infrastructure have specific position, mission, characteristics and behaviour in European Union and Czech state/ business environments, regarding specific requirements for regional and global security environments. They must respect policy of national security and global rules, requirements and standards in all their inherent and outer processes of supply-customer chains and networks. A controlling is generalized capability to have control over situational policy. This paper aims and purposes are to introduce the controlling as quite new necessary process attribute providing for critical infrastructure is environment the capability and profit to achieve its commitment regarding to the effectiveness of the quality management system in meeting customer/ user requirements and also the continual improvement of critical infrastructure organization’s processes overall performance and efficiency, as well as its societal security via continual planning improvement via DYVELOP modelling.

Keywords: added value, DYVELOP, controlling, environments, process approach

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Authors: Bandana Koirala, Shivalal Sharma

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Introduction: Gingival enlargements are quite common and may be either inflammatory, non-inflammatory or a combination of both. Idiopathic gingival enlargement is a rare condition with a proliferative fibrous lesion of the gingival tissue that causes esthetic and functional problems. It is of undetermined etiology. Case Description: This case report addresses the diagnosis and treatment of a case of idiopathic gingival enlargement in a 9-year-old male patient. The patient presented with a generalized diffuse gingival enlargement involving the entire maxillary and the mandibular arch with extension on occlusal, buccal, lingual, and palatal surfaces with just parts of occlusal surfaces of few upper and lower molars visible resulting in open mouth, difficulty in mastication and speech. Biopsy report confirmed the diagnosis of fibromatosis gingivae. Gingivectomy was carried out in all four quadrants by using external bevel incision. Conclusion: Though total esthetics could not be restored due to unusual bony enlargement, the general appearance improved satisfactorily. Treatment after complete excision however, improved the masticatory competence to a great extent.

Keywords: idiopathic gingival fibromatosis, gingival enlargement, gingivectomy, medical and health sciences

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Authors: Elmahdi Elgharbaoui, Tamou Nasser, Ahmed Essadki

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In the era of sustainable development, photovoltaic (PV) technology has shown significant potential as a renewable energy source. Photovoltaic generators (GPV) have a non-linear current-voltage characteristic, with a maximum power point (MPP) characterized by an optimal voltage, and depends on environmental factors such as temperature and irradiation. To extract each time the maximum power available at the terminals of the GPV and transfer it to the load, an adaptation stage is used, consisting of a boost chopper controlled by a maximum power point tracking technique (MPPT) through a stage of pulse width modulation (PWM). Our choice has focused on three techniques which are: the perturbation and observation method (P&O), the incremental conductance method (InCond) and the last is that of control using the fuzzy logic. The implementation and simulation of the system (photovoltaic generator, chopper boost, PWM and MPPT techniques) are then performed in the Matlab/Simulink environment.

Keywords: photovoltaic generator, technique MPPT, boost chopper, PWM, fuzzy logic, P&O, InCond

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Authors: Emhimed Saffor

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In this paper, the problem of edge detection in digital images is considered. Three methods of edge detection based on mathematical morphology algorithm were applied on two sets (Brain and Chest) CT images. 3x3 filter for first method, 5x5 filter for second method and 7x7 filter for third method under MATLAB programming environment. The results of the above-mentioned methods are subjectively evaluated. The results show these methods are more efficient and satiable for medical images, and they can be used for different other applications.

Keywords: CT images, Matlab, medical images, edge detection

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Authors: Tran Le Luu, Jeyong Yoon

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RuO2-TiO2 electrode now becomes popular in the chlor-alkali industry because of high electrocatalytic and stability with chlorine and oxygen evolutions. Using alternative green method for preparation RuO2-TiO2 electrode is necessary to reduce the cost, time. In addition, it is needed to increase the electrocatalyst performance, stability, and environmental compatibility. In this study, the Ti/RuO2-TiO2 electrodes were synthesized using sol-gel method under microwave irradiation and investigated for the anodic chlorine and oxygen evolutions. This method produced small size and uniform distribution of RuO2-TiO2 nanoparticles with mean diameter of 8-10 nm on the big crack size surface which contributes for the increasing of the outer active surface area. The chlorine, oxygen evolution efficiency and stability comparisons show considerably higher for microwave-assisted coated electrodes than for those obtained by the conventional heating method. The microwave-assisted sol-gel route has been identified as a novel and powerful method for quick synthesis of RuO2–TiO2 electrodes with excellent chlorine and oxygen evolution performances.

Keywords: RuO2, electro-catalyst, sol-gel, microwave, chlorine, oxygen evolution

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Authors: Timothy Whitehill

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This paper presents an innovative chat-based focus group method for collecting qualitative data to construct a cause-and-effect analysis in business research. This method was developed in response to the research and data collection challenges faced by the Covid-19 outbreak in the United Kingdom during 2020-21. This paper discusses the methodological approaches and builds a contemporary argument for its effectiveness in exploring cause-and-effect relationships in the context of focus group research, systems thinking and problem structuring methods. The pilot for this method was conducted between October 2020 and March 2021 and collected more than 7,000 words of chat-based data which was used to construct a consensus drawn cause-and-effect analysis. This method was developed in support of an ongoing Doctorate in Business Administration (DBA) thesis, which is using Design Science Research methodology to operationalize organisational resilience in UK construction sector firms.

Keywords: cause-and-effect analysis, focus group research, problem structuring methods, qualitative research, systems thinking

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Authors: Kaouther Selmi, Alaeddine Sridi, Mohamed Bouallegue, Kais Bouallegue

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Neurons are the fundamental units of the brain and the nervous system. The variable structure model of neurons consists of a system of differential equations with various parameters. By optimizing these parameters, we can create a unique model that describes the dynamic behavior of a single neuron. We introduce a neural network based on neurons with multiple dendrites employing an activation function with a variable structure. In this paper, we present a model for heart behavior. Finally, we showcase our successful simulation of the heart's ECG diagram using our Variable Structure Neuron Model (VSMN). This result could provide valuable insights into cardiology.

Keywords: neural networks, neuron, dendrites, heart behavior, ECG

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Authors: A. de Folly d’Auris, R. Bagatin, P. Filtri

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This paper discusses the importance of having a good initial characterization of soil samples when thermal desorption has to be applied to polluted soils for the removal of contaminants. Particular attention has to be devoted on the desorption kinetics of the samples to identify the gases evolved during the heating, and contaminant degradation pathways. In this study, two samples coming from different points of the same contaminated site were considered. The samples are much different from each other. Moreover, the presence of high initial quantity of heavy hydrocarbons strongly affected the performance of thermal desorption, resulting in formation of dangerous intermediates. Analytical techniques such TGA (Thermogravimetric Analysis), DSC (Differential Scanning Calorimetry) and GC-MS (Gas Chromatography-Mass) provided a good support to give correct indication for field application.

Keywords: desorption kinetics, hydrocarbons, thermal desorption, thermogravimetric measurements

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Authors: Rifqi Alfadhillah Sentosa, Hasbi Fikru Syabi, Stephen

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West Java is a province in Indonesia which has a number of volcanoes. One of those volcanoes is Mt. Ciremai, located administratively at Kuningan and Majalengka District, and is known for its significant geothermal potential in Java Island. This research aims to assume geothermal prospects at Mt. Ciremai using Fault and Fracture Density (FFD) Method, which is correlated to the geochemistry of geothermal manifestations around the mountain. This FFD method is using SRTM data to draw lineaments, which are assumed associated with fractures and faults in the research area. These faults and fractures were assumed as the paths for reservoir fluids to reached surface as geothermal manifestations. The goal of this method is to analyze the density of those lineaments found in the research area. Based on this FFD Method, it is known that area with high density of lineaments located on Mt. Kromong at the northern side of Mt. Ciremai. This prospect area is proven by its higher geothermometer values compared to geothermometer values calculated at the south area of Mt. Ciremai.

Keywords: geothermal prospect, fault and fracture density, Mt. Ciremai, surface manifestation

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Authors: Mikhail Zarechnev, Bora I. Kumova

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A syllogism is a deductive inference scheme used to derive a conclusion from a set of premises. In a categorical syllogisms, there are only two premises and every premise and conclusion is given in form of a quantified relationship between two objects. The different order of objects in premises give classification known as figures. We have shown that the ordered combinations of 3 generalized quantifiers with certain figure provide in total of 108 syllogistic moods which can be considered as different inference rules. The classical syllogistic system allows to model human thought and reasoning with syllogistic structures always attracted the attention of cognitive scientists. Since automated reasoning is considered as part of learning subsystem of AI agents, syllogistic system can be applied for this approach. Another application of syllogistic system is related to inference mechanisms on the Semantic Web applications. In this paper we proposed the mathematical model and algorithm for syllogistic reasoning. Also the model of iterative syllogistic reasoning in case of continuous flows of incoming data based on case–based reasoning and possible applications of proposed system were discussed.

Keywords: categorical syllogism, case-based reasoning, cognitive architecture, inference on the semantic web, syllogistic reasoning

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Authors: Sen-Yung Lee, Li-Kuo Chou, Chao-Kuang Chen

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In this study, the problem of temperature transient response of a spiral fin, with its end insulated, is analyzed with base end subjected to a variation of fluid temperature. The hybrid method of Laplace transforms/Adomian decomposed method-Padé, is applied to the temperature transient response of the fin, the result of the temperature distribution and the heat flux at the base of the spiral fin are obtained, show a good agreement in the physical phenomenon.

Keywords: Laplace transforms, Adomian decomposed method- Padé, transient response, heat transfer

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Authors: A. J. Cobley, L. Krishnan

Abstract:

The demand for multi-functional lightweight materials in sectors such as automotive, aerospace, electronics is growing, and for this reason fibre-reinforced, epoxy polymer composites are being widely utilized. The fibre reinforcing material is mainly responsible for the strength and stiffness of the composites whilst the main role of the epoxy polymer matrix is to enhance the load distribution applied on the fibres as well as to protect the fibres from the effect of harmful environmental conditions. The superior properties of the fibre-reinforced composites are achieved by the best properties of both of the constituents. Although factors such as the chemical nature of the epoxy and how it is cured will have a strong influence on the properties of the epoxy matrix, the method of mixing and degassing of the resin can also have a significant impact. The production of a fibre-reinforced epoxy polymer composite will usually begin with the mixing of the epoxy pre-polymer with a hardener and accelerator. Mechanical methods of mixing are often employed for this stage but such processes naturally introduce air into the mixture, which, if it becomes entrapped, will lead to voids in the subsequent cured polymer. Therefore, degassing is normally utilised after mixing and this is often achieved by placing the epoxy resin mixture in a vacuum chamber. Although this is reasonably effective, it is another process stage and if a method of mixing could be found that, at the same time, degassed the resin mixture this would lead to shorter production times, more effective degassing and less voids in the final polymer. In this study the effect of four different methods for mixing and degassing of the pre-polymer with hardener and accelerator were investigated. The first two methods were manual stirring and magnetic stirring which were both followed by vacuum degassing. The other two techniques were ultrasonic mixing/degassing using a 40 kHz ultrasonic bath and a 20 kHz ultrasonic probe. The cured cast resin samples were examined under scanning electron microscope (SEM), optical microscope, and Image J analysis software to study morphological changes, void content and void distribution. Three point bending test and differential scanning calorimetry (DSC) were also performed to determine the thermal and mechanical properties of the cured resin. It was found that the use of the 20 kHz ultrasonic probe for mixing/degassing gave the lowest percentage voids of all the mixing methods in the study. In addition, the percentage voids found when employing a 40 kHz ultrasonic bath to mix/degas the epoxy polymer mixture was only slightly higher than when magnetic stirrer mixing followed by vacuum degassing was utilized. The effect of ultrasonic mixing/degassing on the thermal and mechanical properties of the cured resin will also be reported. The results suggest that low frequency ultrasound is an effective means of mixing/degassing a pre-polymer mixture and could enable a significant reduction in production times.

Keywords: degassing, low frequency ultrasound, polymer composites, voids

Procedia PDF Downloads 295

Authors: Hassan M. Albishri, Abdullah Almalawi, Deia Abd El-Hady

Abstract:

A simple and ecofriendly cyclodextrine-surfactant modified UHPLC (CDS-UPLC) method for rapid and sensitive simultaneous determination of multi water-soluble vitamins such as ascorbic acid, pyridoxine hydrochloride and thiamine hydrochloride in commercial pharmaceuticals and milk samples have been firstly developed. Several chromatographic effective parameters have been changed in a systematic way. Adequate results have been achieved by a mixture of β-cyclodextrine (β-CD) and cationic surfactant under acidic conditions as an eco-friendly isocratic mobile phase at 0.02 mL/min flow rate. The proposed CDS- UHPLC method has been validated for the quantitative determination of multivitamins within 8 min in food and pharmaceutical samples. The method showed excellent linearity for analytes in a wide range of 10-1000 ng/µL. The repeatability and reproducibility of data were about 2.14 and 4.69 RSD%, respectively. The limits of detection (LODs) of analytes ranged between 0.86 and 5.6 ng/µL with a range of 81.8 -115.8% recoveries in tablets and milk samples. The current first CDS- UHPLC method could have vast applications for the precise analysis of multivitamins in complicated matrices.

Keywords: ecofriendly, cyclodextrine-surfactant, multivitamins, UHPLC

Procedia PDF Downloads 268