Search results for: dominant growth models

Authors: Jubee Varghese, Pouria Hafiz

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Increased use of lightweight concrete in the construction industry is mainly due to its reduction in the weight of the structural elements, which in turn reduces the cost of production, transportation, and the overall project cost. However, the structural application of these lightweight concrete structures is limited due to its reduced density. Hence, further investigations are in progress to study the effect of fiber inclusion in improving the mechanical properties of lightweight concrete. Incorporating structural steel fibers, in general, enhances the performance of concrete and increases its durability by minimizing its potential to cracking and providing crack arresting mechanism. In this research, Geometric and Materially Non-linear Analysis (GMNA) was conducted for Finite Element Modelling using a software known as ABAQUS, to investigate the structural behavior of lightweight concrete with and without the addition of steel fibers and shear reinforcement. 21 finite element models of beams were created to study the effect of steel fibers based on three main parameters; fiber volume fraction (Vf = 0, 0.5 and 0.75%), shear span to depth ratio (a/d of 2, 3 and 4) and ratio of area of shear stirrups to spacing (As/s of 0.7, 1 and 1.6). The models created were validated with the previous experiment conducted by H.K. Kang et al. in 2011. It was seen that the lightweight fiber reinforcement can replace the use of fiber reinforced normal weight concrete as structural elements. The effect of an increase in steel fiber volume fraction is dominant for beams with higher shear span to depth ratio than for lower ratios. The effect of stirrups in the presence of fibers was very negligible; however; it provided extra confinement to the cracks by reducing the crack propagation and extra shear resistance than when compared to beams with no stirrups.

Keywords: ABAQUS, beams, fiber-reinforced concrete, finite element, light weight, shear span-depth ratio, steel fibers, steel-fiber volume fraction

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Authors: Susmita Panda, Arnab Banerjee, Ajinkya Baxy, Bappaditya Manna

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The design of short to medium-span high-speed bridges in critical locations is an essential aspect of vehicle-bridge interaction. Due to dynamic interaction between moving load and bridge, mathematical models or finite element modeling computations become time-consuming. Thus, to reduce the computational effort, a universal approximator using an artificial neural network (ANN) has been used to evaluate the dynamic response of the bridge. The data set generation and training of surrogate models have been conducted over the results obtained from mathematical modeling. Further, the robustness of the surrogate model has been investigated, which showed an error percentage of less than 10% with conventional methods. Additionally, the dependency of the dynamic response of the bridge on various load and bridge parameters has been highlighted through a parametric study.

Keywords: artificial neural network, mode superposition method, moving load analysis, surrogate models

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Authors: Valery Gulyayev, Sergey Glazunov, Elena Andrusenko, Nataliya Shlyun

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Enhancement of technology and techniques for drilling deep directed oil and gas bore-wells are of essential industrial significance because these wells make it possible to increase their productivity and output. Generally, they are used for drilling in hard and shale formations, that is why their drivage processes are followed by the emergency and failure effects. As is corroborated by practice, the principal drilling drawback occurring in drivage of long curvilinear bore-wells is conditioned by the need to obviate essential force hindrances caused by simultaneous action of the gravity, contact and friction forces. Primarily, these forces depend on the type of the technological regime, drill string stiffness, bore-hole tortuosity and its length. They can lead to the Eulerian buckling of the drill string and its sticking. To predict and exclude these states, special mathematic models and methods of computer simulation should play a dominant role. At the same time, one might note that these mechanical phenomena are very complex and only simplified approaches (‘soft string drag and torque models’) are used for their analysis. Taking into consideration that now the cost of directed wells increases essentially with complication of their geometry and enlargement of their lengths, it can be concluded that the price of mistakes of the drill string behavior simulation through the use of simplified approaches can be very high and so the problem of correct software elaboration is very urgent. This paper deals with the problem of simulating the regimes of drilling deep curvilinear bore-wells with prescribed imperfect geometrical trajectories of their axial lines. On the basis of the theory of curvilinear flexible elastic rods, methods of differential geometry, and numerical analysis methods, the 3D ‘stiff-string drag and torque model’ of the drill string bending and the appropriate software are elaborated for the simulation of the tripping in and out regimes and drilling operations. It is shown by the computer calculations that the contact and friction forces can be calculated and regulated, providing predesigned trouble-free modes of operation. The elaborated mathematic models and software can be used for the emergency situations prognostication and their exclusion at the stages of the drilling process design and realization.

Keywords: curvilinear drilling, drill string tripping in and out, contact forces, resistance forces

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Authors: Ana Paula Rosifini Alves Claro, André Luiz Reis Rangel, Nathan Trujillo, Ketul C. Popat

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In the present work, in vitro cytotoxicity was evaluated after nanotubes growth on Ti15Mo alloy surface. TiO2 nanotubes were obtained by anodizing technique at room temperature in an electrolyte with 0.25 %NH4F and glycerol at a constant anodic potential of 20 V for 24 hours. The morphology of nanotubes was observed by field emission scanning electron microscopy (FE-SEM; XL 30 FEG, Philips). Crystal structure was analyzed by wide-angle X-ray diffraction. A cell culture model using human fibroblast-like cells was used to study the effect of TiO2 nanotubes growth on the cytotoxicity of the Ti15Mo alloy for 1, 4 and 7 days culture period. The MTT assay was used to evaluate cell viability and cell adhesion was evaluated by scanning electron microscopy. Results show that Ti15Mo alloy with TiO2 nanotubes on surface is nontoxic and exhibit good interaction with surface.

Keywords: titanium alloys, TiO2 nanotubes, cell growth, Ti-15Mo alloy

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Authors: Peter K. Galenko, Stefanie Koch, Markus Rettenmayr, Robert Wonneberger, Evgeny V. Kharanzhevskiy, Maria Zamoryanskaya, Vladimir Ankudinov

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We analyze the structure of undercooled melts, crystal growth kinetics and amorphous/crystalline microstructure of rapidly solidifying glass-forming Pd-based and CuZr-based alloys. A dendrite growth model is developed using a combination of the kinetic phase-field model and mesoscopic sharp interface model. The model predicts features of crystallization kinetics in alloys from thermodynamically controlled growth (governed by the Gibbs free energy change on solidification) to the kinetically limited regime (governed by atomic attachment-detachment processes at the solid/liquid interface). Comparing critical undercoolings observed in the crystallization kinetics with experimental data on melt viscosity, atomistic simulation's data on liquid microstructure and theoretically predicted dendrite growth velocity allows us to conclude that the dendrite growth kinetics strongly depends on the cluster structure changes of the melt. The obtained data of theoretical and experimental investigations are used for interpretation of microstructure of samples processed in electro-magnetic levitator on board International Space Station in the frame of the project "MULTIPHAS" (European Space Agency and German Aerospace Center, 50WM1941) and "KINETIKA" (ROSKOSMOS).

Keywords: dendrite, kinetics, model, solidification

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Authors: A. S. Salimzhanova, J. C. Sardinas, O. A. Yanovskaya

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The objective of this research work is to discuss the concept of green growth in the Republic of Kazakhstan introduced by its government in the National Sustainable Development Strategy with the objective of transition to a resource-efficient, green economy. We believe that emerging economies like Kazakhstan can pursue a cleaner and more efficient development path by introducing an environmental tax system based on resource consumption rather than only income and labor. The key issues discussed in this article are the eco-efficiency, which refers to closing the gap between economic and ecological efficiencies, and the structural change of the economy toward green growth. We also strongly believe that studying the experience of East Asian countries on green reform including eco-innovation and green solutions in business is essential to the case of Kazakhstan. All of these will raise the status of Kazakhstan to the level of one of the thirty developed countries over the next decades.

Keywords: economic strategy, green growth, green solutions, natural resource management, environmental tax system

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Authors: Sekkal Nawel, Mahammed Nadir

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The proliferation of online activities on Online Social Networks (OSNs) has captured significant user attention. However, this growth has been hindered by the emergence of fraudulent accounts that do not represent real individuals and violate privacy regulations within social network communities. Consequently, it is imperative to identify and remove these profiles to enhance the security of OSN users. In recent years, researchers have turned to machine learning (ML) to develop strategies and methods to tackle this issue. Numerous studies have been conducted in this field to compare various ML-based techniques. However, the existing literature still lacks a comprehensive examination, especially considering different OSN platforms. Additionally, the utilization of bio-inspired algorithms has been largely overlooked. Our study conducts an extensive comparison analysis of various fake profile detection techniques in online social networks. The results of our study indicate that supervised models, along with other machine learning techniques, as well as unsupervised models, are effective for detecting false profiles in social media. To achieve optimal results, we have incorporated six bio-inspired algorithms to enhance the performance of fake profile identification results.

Keywords: machine learning, bio-inspired algorithm, detection, fake profile, system, social network

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Authors: Ugbor Raphael Oluchukwu

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Focusing on liquidity comes more naturally to a Chief Executive Officer than an Accountant who is trained to practice accrual accounting. When business is just commencing, it is essentially run on a cheque book (cash accounting) and for as long as there is cash in the accounts, the business is solvent. When complexity sets in and the business adopts financial accounting, the effect of liquidity and cash management becomes more pronounced. The management of cash no doubts impacts positively on the survival and growth of firms. What is in doubt is the amount of cash to be held by a firm as enough cash to enable the firm stay “afloat”. The focus of this paper is to determine liquidity and cash management in business, the Nigerian case. The specific objectives of the study are to do a theoretical review of the amount of cash to be held by a firm as enough cash to enable it stay afloat and to do a theoretical analysis to show the effect of cash flow on the survival and growth of firms in Nigeria.

Keywords: cash, firm survival, growth, liquidity management

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Authors: Animish Jain

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This study deals with using Multiplicative Weight Update within artificial intelligence and machine learning to create models that can diagnose skin cancer using microscopic images of cancer samples. In this study, the multiplicative weight update method is used to take the predictions of multiple models to try and acquire more accurate results. Logistic Regression, Convolutional Neural Network (CNN), and Support Vector Machine Classifier (SVMC) models are employed within the Multiplicative Weight Update system. These models are trained on pictures of skin cancer from the ISIC-Archive, to look for patterns to label unseen scans as either benign or malignant. These models are utilized in a multiplicative weight update algorithm which takes into account the precision and accuracy of each model through each successive guess to apply weights to their guess. These guesses and weights are then analyzed together to try and obtain the correct predictions. The research hypothesis for this study stated that there would be a significant difference in the accuracy of the three models and the Multiplicative Weight Update system. The SVMC model had an accuracy of 77.88%. The CNN model had an accuracy of 85.30%. The Logistic Regression model had an accuracy of 79.09%. Using Multiplicative Weight Update, the algorithm received an accuracy of 72.27%. The final conclusion that was drawn was that there was a significant difference in the accuracy of the three models and the Multiplicative Weight Update system. The conclusion was made that using a CNN model would be the best option for this problem rather than a Multiplicative Weight Update system. This is due to the possibility that Multiplicative Weight Update is not effective in a binary setting where there are only two possible classifications. In a categorical setting with multiple classes and groupings, a Multiplicative Weight Update system might become more proficient as it takes into account the strengths of multiple different models to classify images into multiple categories rather than only two categories, as shown in this study. This experimentation and computer science project can help to create better algorithms and models for the future of artificial intelligence in the medical imaging field.

Keywords: artificial intelligence, machine learning, multiplicative weight update, skin cancer

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Authors: Sanja O. Podunavac-Kuzmanović, Strahinja Z. Kovačević, Lidija R. Jevrić, Stela Jokić

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The subject of this paper is to correlate antibacterial behavior of benzimidazole derivatives with their molecular characteristics using chemometric QSAR (Quantitative Structure–Activity Relationships) approach. QSAR analysis has been carried out on the inhibitory activity of benzimidazole derivatives against Staphylococcus aureus. The data were processed by linear least squares (LLS) and artificial neural network (ANN) procedures. The LLS mathematical models have been developed as a calibration models for prediction of the inhibitory activity. The quality of the models was validated by leave one out (LOO) technique and by using external data set. High agreement between experimental and predicted inhibitory acivities indicated the good quality of the derived models. These results are part of the CMST COST Action No. CM1306 "Understanding Movement and Mechanism in Molecular Machines".

Keywords: Antibacterial, benzimidazoles, chemometric, QSAR.

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Authors: N. E Okoligwe, Okezie A. Ihugba

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Few scholars disagrees that electricity consumption is an important supporting factor for economy growth. However, the relationship between electricity consumption and economy growth has different manifestation in different countries according to previous studies. This paper examines the causal relationship between electricity consumption and economic growth for Nigeria. In an attempt to do this, the paper tests the validity of the modernization or depending hypothesis by employing various econometric tools such as Augmented Dickey Fuller (ADF) and Johansen Co-integration test, the Error Correction Mechanism (ECM) and Granger Causality test on time series data from 1971-2012. The Granger causality is found not to run from electricity consumption to real GDP and from GDP to electricity consumption during the year of study. The null hypothesis is accepted at the 5 per cent level of significance where the probability value (0.2251 and 0.8251) is greater than five per cent level of significance because both of them are probably determined by some other factors like; increase in urban population, unemployment rate and the number of Nigerians that benefit from the increase in GDP and increase in electricity demand is not determined by the increase in GDP (income) over the period of study because electricity demand has always been greater than consumption. Consequently; the policy makers in Nigeria should place priority in early stages of reconstruction on building capacity additions and infrastructure development of the electric power sector as this would force the sustainable economic growth in Nigeria.

Keywords: economic growth, electricity consumption, error correction mechanism, granger causality test

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Authors: Ourvashi Bissoon

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Sub-Saharan Africa in addition to being resource rich is increasingly being seen as having a huge growth potential and as a result, is increasingly attracting MNEs on its soil. To empirically assess the effectiveness of GDP in tracking sustainable resource use and the role played by MNEs in Sub-Saharan Africa, a panel data analysis has been undertaken for 32 countries over thirty-five years. The time horizon spans the period 1980-2014 to reflect the evolution from before the publication of the pioneering Brundtland report on sustainable development to date. Multinationals’ presence is proxied by the level of FDI stocks. The empirical investigation first focuses on the impact of trade openness and MNE presence on the traditional measure of economic growth namely the GDP growth rate, and then on the genuine savings (GS) rate, a measure of weak sustainability developed by the World Bank, which assumes the substitutability between different forms of capital and finally, the impact on the adjusted Net National Income (aNNI), a measure of green growth which caters for the depletion of natural resources is examined. For countries with significant exhaustible natural resources and important foreign investor presence, the adjusted net national income (aNNI) can be a better indicator of economic performance than GDP growth (World Bank, 2010). The issue of potential endogeneity and reverse causality is also addressed in addition to robustness tests. The findings indicate that FDI and openness contribute significantly and positively to the GDP growth of the countries in the sample; however there is a threshold level of institutional quality below which FDI has a negative impact on growth. When the GDP growth rate is substituted for the GS rate, a natural resource curse becomes evident. The rents being generated from the exploitation of natural resources are not being re-invested into other forms of capital namely human and physical capital. FDI and trade patterns may be setting the economies in the sample on a unsustainable path of resource depletion. The resource curse is confirmed when utilising the aNNI as well, thus implying that GDP growth measure may not be a reliable to capture sustainable development.

Keywords: FDI, sustainable development, genuine savings, sub-Saharan Africa

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Authors: Karina Reiter, Stefan Dullinger, Christoph Plutzar, Dietmar Moser

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Due to population growth and changing patterns of production and consumption, the demand for natural resources and, as a result, the pressure on Earth’s ecosystems are growing. Biodiversity mapping can be a useful tool for assessing species endangerment or detecting hotspots of extinction risks. This paper explores the benefits of using the change in trophic energy flows as a consequence of the human alteration of the biosphere in biodiversity mapping. To this end, multiple linear regression models were developed to explain species richness in areas where there is no human influence (i.e. wilderness) for three taxonomic groups (birds, mammals, amphibians). The models were then applied to predict (I) potential global species richness using potential natural vegetation (NPPpot) and (II) global ‘actual’ species richness after biomass appropriation using NPP remaining in ecosystems after harvest (NPPeco). By calculating the difference between predicted potential and predicted actual species numbers, maps of estimated species richness loss were generated. Results show that biomass appropriation for human use can indeed be linked to biodiversity loss. Areas for which the models predicted high species loss coincide with areas where species endangerment and extinctions are recorded to be particularly high by the International Union for Conservation of Nature and Natural Resources (IUCN). Furthermore, the analysis revealed that while the species distribution maps of the IUCN Red List of Threatened Species used for this research can determine hotspots of biodiversity loss in large parts of the world, the classification system for threatened and extinct species needs to be revised to better reflect local risks of extinction.

Keywords: biodiversity loss, biomass harvest, human appropriation of net primary production, species richness

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Authors: M. Sakthivel, A. Devaki, D. Balasubramanyam, P. Kumarasamy, A. Raja, R. Anilkumar, H. Gopi

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The influence of inbreeding on growth traits in the New Zealand White rabbits maintained at Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India was studied in a closed herd. Data were collected over a period of 15 years (1998 to 2012). The traits studied were body weights at weaning (W42), post-weaning (W70) and marketing (W135) age and growth efficiency traits viz., average daily gain (ADG), relative growth rate (RGR) and Kleiber ratio (KR) estimated on a daily basis at different age intervals (1=42 to 70 days; 2=70 to 135 days and 3=42 to 135 days) from weaning to marketing. The effects of inbreeding along with other non-genetic factors (sex of the kit, season and period of birth of the kit) were analyzed using least-squares method. The inbreeding (F) and equivalent inbreeding (EF) coefficients were taken as fixed classes as well as covariates in separate analyses. When taken as covariate, the effect was analyzed as partial regression of respective growth trait on individual inbreeding coefficient (F or EF). The mean body weights at weaning, post-weaning and marketing were 0.715, 1.276 and 2.187 kg, respectively. The maximum growth efficiency was noticed between weaning and post-weaning. Season and period had highly significant influence on all the growth parameters studied and sex of the kit had significant influence on certain growth efficiency traits only. The average coefficients of inbreeding and equivalent inbreeding in the population were 13.233 and 17.585 percent, respectively. About 11.17 percent of total matings were highly inbred in which full-sib, half-sib and parent-offspring matings were 1.20, 6.30 and 3.67 percent, respectively. The regression of body weight traits on F and EF showed negative effect whereas most of the growth efficiency traits showed positive effects. Significant inbreeding depression was observed in W42 and W70. The depression in W42 was 0.214 kg and 0.139 kg and in W70 was 0.269 kg and 0.172 kg for every one unit increase in F and EF, respectively. Though the trait W135 showed positive value and ADG1 showed depression, the effects of inbreeding and equivalent inbreeding were non-significant in these traits. Higher values of inbreeding depression could be due to more variance of F or EF in the population. The analysis of the effect of level of inbreeding on growth traits revealed that the inbreeding class was significant on W70, ADG2, RGR2 and KR2 while EF classes had significant influence only on ADG2, RGR2 and KR2. Obviously, inbreeding does not have a positive effect, therefore, these results suggest that inbreeding had no effect on these traits.

Keywords: growth parameters, equivalent inbreeding, inbreeding effects, rabbit genetics

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Authors: Ahmed F. Elaksher, Islam Omar

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In this project, we used MOLA-based DEMs to orthorectify HiRISE optical images. The MOLA data was interpolated using the kriging interpolation technique. Corresponding tie points were then digitized from both datasets. These points were employed in co-registering both datasets using GIS analysis tools. Different transformation models, including the affine and projective transformation models, were used with different sets and distributions of tie points. Additionally, we evaluated the use of the MOLA elevations in co-registering the MOLA and HiRISE datasets. The planimetric RMSEs achieved for each model are reported. Results suggested the use of 3D-2D transformation models.

Keywords: photogrammetry, Mars, MOLA, HiRISE

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Authors: Ewa Mojs, Katarzyna Wiechec, Maia Kubiak, Wlodzimierz Samborski

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Interactions between mother’s psychological condition and child’s health status are complex and derive from the nature of the mother-child relationship. The aim of the study was to analyze the issue of anxiety amongst mothers of short children in the aspect of growth hormone therapy. The study was based on a group of 101 mothers of originally short-statured children – 70 with growth hormone deficiency (GHD) treated with recombinant human growth hormone (rhGH) and 31 undergoing the diagnostic process, without any treatment. Collected medical data included child's gender, height and weight, chronological age, bone age delay, and rhGH therapy duration. For all children, the height SDS and BMI SDS were calculated. To evaluate anxiety in mothers, the Spielberger State-Trait Anxiety Inventory (STAI) was used. Obtained results revealed low trait anxiety levels, with no statistically significant differences between the groups. State anxiety levels were average when mothers of all children were analyzed together, but when divided into groups, statistical differences appeared. Mothers of children without diagnosis and treatment had significantly higher levels of state anxiety than mothers of children with GHD receiving appropriate therapy. These results show, that the occurrence of growth failure in children is not related to high maternal trait anxiety, but the lack of diagnosis and lack of appropriate treatment generates higher levels of maternal state anxiety than the process of rh GH therapy in the offspring. Commencement of growth hormone therapy induce a substantial reduction of the state anxiety in mothers, and the duration of treatment causes its further decrease.

Keywords: anxiety, development, growth hormone deficiency, motherhood

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Authors: Legkikh Victoria

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The purpose of keeping bi/multilingualism is usually a way to let the child speak two/three languages at the same level. The main problem which normally appears is a mixed language or a domination of one language. The same level of two or more languages would be ideal but practically not easily reachable. So it was made an experiment with a girl with a natural multilingualism as an attempt to avoid a dominant language in the preschool age. The girl lives in Germany and the main languages for her are Italian, Russian and German but she also hears every day English. ‘One parent – one language’ strategy was used since the beginning so Italian and Russian were spoken to her since her birth, English was spoken between the parents and when she was 1,5 it was added German as a language of a nursery. In order to avoid a dominant language, she was always put in international groups with activity in different languages. Even if it was not possible to avoid an interference of languages in this case we can talk not only about natural multilingualism but also about balanced bilingualism in preschool time. The languages have been developing in parallel with different accents in a different period. Now at the age of 6 we can see natural horizontal multilingualism Russian/Italian/German/English. At the moment, her Russian/Italian bilingualism is balanced. German vocabulary is less but the language is active and English is receptive. We can also see a reciprocal interference of all the three languages (English is receptive so the simple phrases are normally said correctly but they are not enough to judge the level of language interference and it is not noticed any ‘English’ mistakes in other languages). After analysis of the state of every language, we can see as a positive and negative result of the experiment. As a positive result we can see that in the age of 6 the girl does not refuse any language, three languages are active, she differentiate languages and even if she says a word from another language she notifies that it is not a correct word, and the most important are the fact, that she does not have a preferred language. As a prove of the last statement it is to be noticed not only her self-identification as ‘half Russian and half Italian’ but also an answer to the question about her ‘mother tongue’: ‘I do not know, probably, when I have my own children I will speak one day Russian and one day Italian and sometimes German’. As a negative result, we can notice that not only a development of all the three languages are a little bit slower than it is supposed for her age but since she does not have a dominating language she also does not have a ‘perfect’ language and the interference is reciprocal. In any case, the experiment shows that it is possible to keep at least two languages without a preference in a pre-school multilingual space.

Keywords: balanced bilingualism, language interference, natural multilingualism, preschool multilingual education

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Authors: Saad M. Howladar, Mike Dennett

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The effect of salinity (0-200 mMNaCl) on wheat growth (leaf and tiller numbers, and fresh and dry weights) underseed soaking (6 and 24 hs) insalicylic acid (SA) was investigated. The impact of salinity was less pronounced in salt tolerant cultivars (Sakha 93 and S24) than Paragon and S24. Chlorophyll content was increased as a response to salinity stress. It was raised in 100 mMNaCl more than 200 mMNaCl. The same trend was found in 24 hs soaking, except chlorophyll content in Paragon and S24 under 200 mMNaCl was more than 100 mMNaCl. SA application induced a positive effect on growth parameters in some cultivars, particularly Paragon under saline and non-saline condition. Soaking for 6 hs was more effective than 24 hs soaking, especially in Paragon and Sakha 93. SA supply caused a slight effect on chlorophyll content but this was not significant and there was no significant difference between both soaking hs. The effect of SA on growth parameters and chlorophyll content depends on cultivar genotype and SA concentration.

Keywords: salinity, salicylic acid, growth parameters, chlorophyll content, wheat cultivars

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Authors: S. Gordon

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Dual language immersion is growing fast in language teaching today. This study provides an overview and evaluation of the different models of Dual language immersion programs in US K-12 schools. First, the paper provides a brief current literature review on the theory of Dual Language Immersion (DLI) in Second Language Acquisition (SLA) studies. Second, examples of several types of DLI language teaching models in US K-12 public schools are presented (including 50/50 models, 90/10 models, etc.). Third, we focus on the unique example of DLI education in the state of Utah, a successful, growing program in K-12 schools that includes: French, Chinese, Spanish, and Portuguese. The project investigates the theory and practice particularly of the case of public elementary and secondary school children that study half their school day in the L1 and the other half in the chosen L2, from kindergarten (age 5-6) through high school (age 17-18). Finally, the project takes the observations of Utah French DLI elementary through secondary programs as a case study. To conclude, we look at the principal challenges, pedagogical objectives and outcomes, and important implications for other US states and other countries (such as France currently) that are in the process of developing similar language learning programs.

Keywords: dual language immersion, second language acquisition, language teaching, pedagogy, teaching, French

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Authors: Lazhar mouloud, Chemat Zoubida, Ouhoumna Faiza

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The main objective of this study, concerns the modeling of breakthrough curves obtained in the adsorption column of malachite green into alginate-encapsulated aluminium pillared clay in fixed bed according to various operating parameters such as the initial concentration, the feed rate and the height fixed bed, applying mathematical models namely: the model of Bohart and Adams, Wolborska, Bed Depth Service Time, Clark and Yoon-Nelson. These models allow us to express the different parameters controlling the performance of the dynamic adsorption system. The results have shown that all models were found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to the flow rate, the inlet dye concentration and the height of fixed bed.

Keywords: adsorption column, malachite green, pillared clays, alginate, modeling, mathematic models, encapsulation.

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Authors: Mingyue Sheng, Basil Sharp

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Greenhouse gas (GHG) emissions from national transport account for the largest share of emissions from energy use in New Zealand. Whether the environmental Kuznets curve (EKC) relationship exists between environmental degradation indicators from the transport sector and economic growth in New Zealand remains unclear. This paper aims at exploring the causality relationship between CO₂ emissions from the transport sector, fossil fuel consumption, and the Gross Domestic Product (GDP) per capita in New Zealand, using annual data for the period 1977 to 2013. First, conventional unit root tests (Augmented Dickey–Fuller and Phillips–Perron tests), and a unit root test with the breakpoint (Zivot-Andrews test) are employed to examine the stationarity of the variables. Second, the autoregressive distributed lag (ARDL) bounds test for co-integration, followed by Granger causality investigated causality among the variables. Empirical results of the study reveal that, in the short run, there is a unidirectional causality between economic growth and transport CO₂ emissions with direction from economic growth to transport CO₂ emissions, as well as a bidirectional causality from transport CO₂ emissions to road energy consumption.

Keywords: economic growth, transport carbon dioxide emissions, environmental Kuznets curve, causality

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Authors: A. S. V. Carvalho, J. Luis, L. S. O. Pires, J. M. Oliveira

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Additive manufacturing technologies (AM) experienced a remarkable growth in the latest years due to the development and diffusion of a wide range of three-dimensional (3D) printing techniques. Nowadays we can find techniques available for non-industrial users, like fused filament fabrication, but techniques like 3D printing, polyjet, selective laser sintering and stereolithography are mainly spread in the industry. Robocasting (R3D) shows a great potential due to its ability to shape materials with a wide range of viscosity. Industrial porcelain compositions showing different rheological behaviour can be prepared and used as candidate materials to be processed by R3D. The use of this AM technique in industry is very residual. In this work, a specific porcelain composition with suitable rheological properties will be processed by R3D, and a systematic study of the printing parameters tuning will be shown. The porcelain composition was formulated based on an industrial spray dried porcelain powder. The powder particle size and morphology was analysed. The powders were mixed with water and an organic binder on a ball mill at 200 rpm/min for 24 hours. The batch viscosity was adjusted by the addition of an acid solution and mixed again. The paste density, viscosity, zeta potential, particle size distribution and pH were determined. In a R3D system, different speed and pressure settings were studied to access their impact on the fabrication of porcelain models. These models were dried at 80 °C, during 24 hours and sintered in air at 1350 °C for 2 hours. The stability of the models, its walls and surface quality were studied and their physical properties were accessed. The microstructure and layer adhesion were observed by SEM. The studied processing parameters have a high impact on the models quality. Moreover, they have a high impact on the stacking of the filaments. The adequate tuning of the parameters has a huge influence on the final properties of the porcelain models. This work contributes to a better assimilation of AM technologies in ceramic industry. Acknowledgments: The RoboCer3D project – project of additive rapid manufacturing through 3D printing ceramic material (POCI-01-0247-FEDER-003350) financed by Compete 2020, PT 2020, European Regional Development Fund – FEDER through the International and Competitive Operational Program (POCI) under the PT2020 partnership agreement.

Keywords: additive manufacturing, porcelain, robocasting, R3D

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Authors: Zahir Bakiri, Saci Nacefa

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In this paper a comparison in made between two models, with and without dispersion term, and focused on the characterization of the movement of the sludge blanket in the secondary sedimentation tank using the solid flux theory and the velocity settling. This allowed us develop a one-dimensional models, with and without dispersion based on a thorough experimental study carried out in situ and the application of online data which are the mass load flow, transfer concentration, and influent characteristic. On the other hand, in the proposed model, the new settling velocity law (double-exponential function) used is based on the Vesilind function.

Keywords: wastewater, activated sludge, sedimentation, settling velocity, settling models

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Authors: Cleopatra Oluseye Ibukun

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Following the endogenous growth theory, entrepreneurship has been considered pivotal to economic growth and development, particularly in developing countries like Nigeria. Meanwhile, efforts to reduce unemployment has yielded minimal result with over 36% of youth unemployment and a dwindling economic growth despite the country’s natural and human resource endowment. This study, therefore, investigates the effects of entrepreneurship and institutional quality on economic growth and unemployment in Nigeria over the period 1996 to 2018. The data is obtained from the National Bureau of Statistics (NBS), World Bank’s World Development Indicators (WDI), and the World Bank’s World Governance Indicators (WGI). The study period is guided by the availability of data, and the study employs both descriptive and econometric techniques of analysis (specifically, the Auto-regressive Distributed Lag Approach). This approach is preferable given that the variables are stationary at the first difference, while the bounds test suggests the existence of co-integration among the variables. By implication, an increase in entrepreneurship significantly improves economic growth, and it reduces unemployment in both the short-run and the long-run. Besides, institutional quality proxied by the control of corruption, political stability, and government effectiveness significantly mediates the interaction between entrepreneurship and macroeconomic performance. This study concludes that improved institutional quality enhances the effect of entrepreneurship on economic growth and unemployment in Nigeria, and it recommends an improvement in Nigeria’s institutional quality because it can jeopardise or augment the effect of entrepreneurship on macroeconomic performance.

Keywords: entrepreneurship, institutional quality, unemployment, gross domestic product, Nigeria

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Authors: Assaad Ghazouani

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Tunisia is ranked among the countries with low energy diversification, but this configuration makes the country too dependent on fossil fuel exporting countries and therefore extremely sensitive to any oil crises, many measures to diversify electricity production must be taken in making use of other forms of renewable and nuclear energy. One of the solutions required to escape this dependence is the liberalization of the electricity industry which can lead to an improvement of supply, energy diversification, and reducing some of the negative effects of the trade balance. This paper examines the issue of renewable electricity and economic growth in Tunisia consumption. The main objective is to study and analyze the causal link between renewable energy consumption and economic growth in Tunisia over the period 1980-2010. To examine the relationship in the short and in the long terms, we used a multidimensional approach to cointegration based on recent advances in time series econometrics (test Zivot - Andrews, Test of Cointegration Johannsen, Granger causality test, error correction model (ECM)).

Keywords: renewable electricity, economic growth, VECM, cointegration, Tunisia

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Authors: S. O. Okoro

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Some words become the catch phrase of a particular decade. Globalization, Openness, and Privatization are certainly among the most frequently encapsulation of 1990’s; the market is ‘in’, ‘the state is out’. In the 1970’s, there were many political economists who spoke of autarky as one possible response to global economic forces. Be self-contained, go it alone, put up barriers to trans-nationalities, put in place import-substitution industrialization policy and grow domestic industries. In 1990’s, the emasculation of the state is by no means complete, but there is an acceptance that the state’s power is circumscribed by forces beyond its control and potential leverage. Autarky is no longer as a policy option. Nigeria, since its emergence as an independent nation, has evolved two macroeconomic management regimes of the interventionist and market friendly styles. This paper investigates Nigeria’s growth performance over the periods incorporating these two regimes and finds that there is no structural break in Total Factor Productivity, (TFP) growth and besides, the TFP growth over the entire period of study 1970-2012 is very negligible and hence growth can only be achieved by the unsustainable factor accumulation. Another important finding of this work is that the openness-human capital interaction term has a significant impact on the TFP growth, but the sign of the estimated coefficient does not meet it a theoretical expectation. This is because the negative coefficient on the human capital outweighs the positive openness effect. The poor quality of human capital is considered to have given rise to this. Given these results a massive investment in the education sector is required. The investment should be targeted at reforms that go beyond mere structural reforms to a reform agenda that will improve the quality of human capital in Nigeria.

Keywords: globalization, emasculation, openness and privatization, total factor productivity

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Authors: Htet Khaing Lin

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This study explores the relationship between a diverse set of variables, encompassing both environmental and socio-economic factors, and poverty levels in the Philippines for the years 2012, 2015, and 2018. Employing Ordinary Least Squares (OLS), Spatial Lag Models (SLM), and Spatial Error Models (SEM), this study delves into the dynamics of key indicators, including daytime and nighttime land surface temperature, cropland surface, urban land surface, rainfall, population size, normalized difference water, vegetation, and drought indices. The findings reveal consistent patterns and unexpected correlations, highlighting the need for nuanced policies that address the multifaceted challenges arising from the interplay of environmental and socio-economic factors.

Keywords: poverty analysis, OLS, spatial lag models, spatial error models, Philippines, google earth engine, satellite data, environmental dynamics, socio-economic factors

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Authors: Gylych Jelilov

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This paper investigates the effect of foreign debt on economic growth. Example has been chosen from Africa, Nigeria. By conducting cointegration test we have tested for a long-run relationship between. GDP = Real gross domestic product, EXTDEBT = External debt, INT = Interest rate, CAB = Current account balance, and EXCHR = Real exchange rate over the period 1990 to 2012. It was found out by the study that there is a negative but insignificant relationship between external debt and real gross domestic product. While a positive relationship exists between external debt and economic growth. Also, showed a negative and significant relationship between interest rate and real gross domestic product and there was a positive but insignificant relationship between current account balance and real gross domestic product.

Keywords: economic growth, foreign debt, Nigeria, sustainable development, economic stability

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Authors: Himali N. Balasooriya, Kithsiri B. Dassanayake, Saman Seneweera, Said Ajlouni

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Increase in atmospheric CO₂ concentration [CO₂] and ambient temperature associated with changing climatic conditions will have significant impacts on agriculture crop productivity and quality. Independent effects of the above two environmental variables on the growth, yield and quality of strawberry were well documented. Higher temperatures over the optimum range (20-25ºC) lead to crop failures, while elevated [CO₂] stimulated plant growth and yield but compromised the physical quality of fruits. However, there is very limited understanding of the interaction between these variables on the plant growth, yield and quality. Therefore, this study was designed to investigate the interactive effect of high temperature and elevated [CO₂] on growth, yield and quality of strawberries. Strawberry cultivars ‘Albion’ and ‘San Andreas’ were grown under six different combinations of two temperatures (25 and 30ºC) and three [CO₂] (400, 650 and 950 µmol mol^-1) in controlled-environmental growth chambers. Plant growth measurements such as plant height, canopy area, number of flowers, and fruit yield were measured during phonological development. Photosynthesis and transpiration, the ratio of intercellular to atmospheric [CO₂] (Ci/Ca) were measured to estimate the physiological adjustment to climate stress. The impact of temperature and [CO₂] interaction on growth and yield of strawberry was significant (p < 0.05). Across both cultivars, highest fruit yields were observed at 650 µmol mol^-1 [CO₂], which was particularly clear at 25°C. The fruit yield gradually decreased at 30°C under all the treatment combinations. However, photosynthesis rates were highest at 650 µmol mol^-1 [CO₂] but no increment was found at 900 µmol mol^-1 [CO₂]. Interestingly, Ci/Ca ratio increased with increasing atmospheric [CO₂] which was predominant at high temperature. Similarly, fruit yield was substantially reduced at high [CO₂] under high temperature. Our findings suggest that increased Ci/Ca ratio at high temperature is likely reduces the photosynthesis and thus yield response to elevated [CO₂].

Keywords: atmospheric CO₂ concentration, fruit yield, strawberry, temperature

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Authors: M. A. Meslem

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For precise geoid determination, we use a reference field to subtract long and medium wavelength of the gravity field from observations data when we use the remove-compute-restore technique. Therefore, a comparison study between considered models should be made in order to select the optimal reference gravity field to be used. In this context, two recent global geopotential models have been selected to perform this comparison study over Northern Algeria. The Earth Gravitational Model (EGM2008) and the Global Gravity Model (GECO) conceived with a combination of the first model with anomalous potential derived from a GOCE satellite-only global model. Free air gravity anomalies in the area under study have been used to compute residual data using both gravity field models and a Digital Terrain Model (DTM) to subtract the residual terrain effect from the gravity observations. Residual data were used to generate local empirical covariance functions and their fitting to the closed form in order to compare their statistical behaviors according to both cases. Finally, height anomalies were computed from both geopotential models and compared to a set of GPS levelled points on benchmarks using least squares adjustment. The result described in details in this paper regarding these two models has pointed out a slight advantage of GECO global model globally through error degree variances comparison and ground-truth evaluation.

Keywords: quasigeoid, gravity aomalies, covariance, GGM

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