Search results for: agreement parameters

Authors: Péter Sipos, Gerda Diósi, Mariann Móré, Zsófia Szigeti

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Several medical research found that the sodium is one of the main risk factor of high blood pressure and reason for different cardiovascular diseases, while sodium chloride is one of the most ancient food additives. As people consume much more sodium chloride as the recommended value several salt reduction programs started worldwide in the last years. The cereal products are the main source of sodium, and the bakery products are one of the main targets of these programs. In this paper we have evaluated the effects of different concentrations of sodium chloride on the alveo graphical and extensi graphical parameters of rye flours to determine whether it has the same strengthening effect on the dough texture as it was found in the case of wheat flours and these effects were compared to the effects of other salt forms. We found that while the strength of rye flours are similar to the ones of wheat flour, rye flours are much less extensible. The effects of salt concentrations are less significant on the rheological properties of rye flour than on the wheat flour and there is no significant difference between the effects of different salts.

Keywords: alveograph, extensigraph, rye flour, salt

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Authors: Rilwan Kayode Apalowo, Dimitrios Chronopoulos

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An approach for identifying the geometric and material characteristics of layered composite structures through an inverse wave and finite element methodology is proposed. These characteristics are obtained through multi-frequency single shot measurements. However, it is established that the frequency regime of the measurements does not matter, meaning that both ultrasonic and structural dynamics frequency spectra can be employed. Taking advantage of a full FE (finite elements) description of the periodic composite, the scheme is able to account for arbitrarily complex structures. In order to demonstrate the robustness of the presented scheme, it is applied to a sandwich composite panel and results are compared with that of experimental characterization techniques. Excellent agreement is obtained with the experimental measurements.

Keywords: structural identification, non-destructive evaluation, finite elements, wave propagation, layered structures, ultrasound

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Authors: S. Dey, T. Mukhopadhyay, S. Adhikari

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This paper presents an exhaustive comparative investigation on sampling techniques of polynomial regression model based stochastic natural frequency of composite plates. Both individual and combined variations of input parameters are considered to map the computational time and accuracy of each modelling techniques. The finite element formulation of composites is capable to deal with both correlated and uncorrelated random input variables such as fibre parameters and material properties. The results obtained by Polynomial regression (PR) using different sampling techniques are compared. Depending on the suitability of sampling techniques such as 2k Factorial designs, Central composite design, A-Optimal design, I-Optimal, D-Optimal, Taguchi’s orthogonal array design, Box-Behnken design, Latin hypercube sampling, sobol sequence are illustrated. Statistical analysis of the first three natural frequencies is presented to compare the results and its performance.

Keywords: composite plate, natural frequency, polynomial regression model, sampling technique, uncertainty quantification

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Authors: Hadi Farhadian, Homayoon Katibeh

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Groundwater inflow to the tunnels is one of the most important problems in tunneling operation. The objective of this study is the investigation of model dimension effects on tunnel inflow assessment in discontinuous rock masses using numerical modeling. In the numerical simulation, the model dimension has an important role in prediction of water inflow rate. When the model dimension is very small, due to low distance to the tunnel border, the model boundary conditions affect the estimated amount of groundwater flow into the tunnel and results show a very high inflow to tunnel. Hence, in this study, the two-dimensional universal distinct element code (UDEC) used and the impact of different model parameters, such as tunnel radius, joint spacing, horizontal and vertical model domain extent has been evaluated. Results show that the model domain extent is a function of the most significant parameters, which are tunnel radius and joint spacing.

Keywords: water inflow, tunnel, discontinues rock, numerical simulation

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Authors: Maria Santana, Jose Estaire

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Even though recycling strategies are becoming more important in recent years, there is still a huge amount of industrial by-products that are the disposal of at landfills. Due to the size, possible dangerous composition, and heterogeneity, most of the wastes are located at landfills without a basic geotechnical characterization. This lack of information may have an important influence on the correct stability calculations. This paper presents the results of geotechnical characterization of some industrial wastes disposed at one landfill. The shear strength parameters were calculated based on direct shear test results carried out in a large shear box owned by CEDEX, which has a shear plane of 1 x 1 m. These parameters were also compared with the results obtained in a 30 x 30 cm shear box. The paper includes a sensitive analysis of the global safety factor of the landfill's overall stability as a function of shear strength variation. The stability calculations were assessed for various hydrological scenarios to simulate the design and performance of the leachate drainage system. The characterization was completed with leachate tests to study the potential impact on the environment.

Keywords: industrial wastes, landfill, leachate tests, stability

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Authors: Aleksander Veraksa, Alla Tvardovskaya, Margarita Gavrilova, Vera Yakupova, Martin Musálek

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Considering the current agreement on the significance of executive functions, there is growing interest in determining factors that contribute to the development of these skills, especially during the preschool period. Although multiple studies have been focusing on links between physical activity, physical fitness and executive functions, this topic was more investigated in schoolchildren and adults than in preschoolers. The aim of the current study was to identify different levels of physical fitness among pre-schoolers, followed by an analysis of differences in their executive functions. Participants were 261 5-6-years old children. Inhibitory control and working memory were positively linked with physical fitness. Cognitive flexibility was not associated with physical fitness. The research findings are considered from neuropsychological grounds, Jean Piaget's theory of cognitive development, and the cultural-historical approach.

Keywords: cognitive flexibility, inhibitory control, physical activity, physical fitness, working memory.

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Authors: Charaia Vakhtang

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Global oil prices are seeing new bottoms every day. The prices have already collapsed beneath the psychological verge of 30 USD. This tendency would be fully acceptable for the Georgian consumers, but there is one detail: two our neighboring countries (one friendly and one hostile) largely depend on resources of these hydrocarbons. Namely, the ratio of Azerbaijan in Georgia’s total FDI inflows in 2014 marked 20%. The ratio reached 40% in the January to September 2015. Azerbaijan is Georgia’s leading exports market. Namely, in 2014 Georgia’s exports to Azerbaijan constituted 544 million USD, i.e. 19% in Georgia’s total experts. In the January to November period of 2015, the ratio exceeded 11%. Moreover, Azerbaijan is Georgia’s strategic partner country as part of many regional projects that are designated for long-term perspectives. For example, the Baku-Tbilisi-Karsi railroad, the Black Sea terminal, preferential gas tariffs for Georgia and so on. The Russian economic contribution to the Georgian economy is also considerable, despite the losses the Russian hostile policy has inflicted to our country. Namely, Georgian emigrants are mainly employed in the Russian Federation and this category of Georgian citizens transfers considerable funds to Georgia every year. These transfers account for about 1 billion USD and consequently, these funds previously equalized to total FDI inflows. Moreover, despite the difficulties in the Russian market, Russia still remains a leader in terms of money transfers to Georgia. According to the last reports, money transfers from Russia to Georgia slipped by 276 million USD in 2015 compared to 2014 (-39%). At the same time, the total money transfers to Georgia in 2015 marked 1.08 billion USD, down 25% from 1.44 billion USD in 2014. This signifies the contraction in money transfers is by ¾ dependent on the Russian factor (in this case, contraction in oil prices and the Russian Ruble devaluation directly make negative impact on money transfers to Georgia). As to other countries, it is interesting that money transfers have also slipped from Italy (to 109 million USD from 121 million USD). Nevertheless, the country’s ratio in total money transfers to Georgia has increased to 10% from 8%. Money transfers to Georgia have increased by 22% (+18 million USD) from the USA. Money transfers have halved from Greece to 117 million USD from 205 million USD. As to Turkey, money transfers to Georgia from Turkey have increased by 1% to 69 million USD. Moreover, the problems with the national currencies of Russia and Azerbaijan, along with the above-mentioned developments, outline unfavorable perspectives for the Georgian economy. The depreciation of the national currencies of Azerbaijan and Russia is expected to bring unfavorable results for the Georgian economy. Even more so, the statement released by the Russian Finance Ministry on expected default is in direct relation to the welfare of the whole region and these tendencies will make direct and indirect negative impacts on Georgia’s economic indicators. Amid the economic slowdown in Armenia, Turkey and Ukraine, Georgia should try to enhance economic ties with comparatively stronger and flexible economies such as EU and USA. In other case, the Georgian economy will enter serious turbulent zone. We should make maximum benefit from the EU association agreement. It should be noted that the Russian economy slowdown that causes both regretful and happy moods in Georgia, will make negative impact on the Georgian economy. The same forecasts are made in relation to Azerbaijan. However, Georgia has many partner countries. Enhancement and development of the economic relations with these countries may maximally alleviate negative impacts from the declining economies. First of all, the EU association agreement should be mentioned as a main source for Georgia’s economic stabilization. It is the Georgian government‘s responsibility to successfully fulfill the EU association agreement requirements. In any case the imports must be replaced by domestic products and the exports should be stimulated through government support programs. The Authorities should ensure drawing more foreign investments and money resources, accumulating more tourism revenues and reducing external debts, budget expenditures should be balanced and the National Bank should carry out strict monetary policy. Moreover, the Government should develop a long-term state economic policy and carry out this policy at various Ministries. It is also of crucial importance to carry out constitutive policy and promote perspective directions on the domestic level.

Keywords: oil prices, economic growth, foreign direct investments, international trade

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Authors: Daniel O'Shea, Mario M. Attard, David C. Kellermann

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In this paper, we propose a hyperelastic strain energy function that maps isotopic hyperelastic constitutive laws for the use of orthotropic materials without the use of structural tensors or any kind of fiber vector, or the use of standard invariants. In particular, we focus on neo-Hookean class of models and represent them using an invariant-free formulation. To achieve this, we revise the invariant-free formulation of isotropic hyperelasticity. The formulation uses quadruple contractions between fourth-order tensors, rather than scalar products of scalar invariants. We also propose a new decomposition of the orthotropic Hookean stiffness tensor into two fourth-order Lamé tensors that collapse down to the classic Lamé parameters for isotropic continua. The resulting orthotropic hyperelastic model naturally maintains all of the advanced properties of the isotropic counterparts, and similarly collapse back down to their isotropic form by nothing more than equality of parameters in all directions (isotropy). Comparisons are made with large strain experimental results for transversely isotropic rubber type materials under tension.

Keywords: finite strain, hyperelastic, invariants, orthotropic

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Authors: Sabine Ambros, Mine Oezcelik, Evelyn Dachmann, Ulrich Kulozik

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Nutritional quality and taste of dried fruit products is still often unsatisfactory and does not meet anymore the current consumer trends. Dried foams from fruit puree could be an attractive alternative. Due to their open-porous structure, a new sensory perception with a sudden and very intense aroma release could be generated. To make such high quality fruit snacks affordable for the consumer, a gentle but at the same time fast drying process has to be applied. Therefore, microwave-assisted freeze drying of raspberry foams was investigated in this work and compared with the conventional freeze drying technique in terms of nutritional parameters such as antioxidative capacity, anthocyanin content and vitamin C and the physical parameters colour and wettability. The following process settings were applied: 0.01 kPa chamber pressure and a maximum temperature of 30 °C for both freeze and microwave freeze drying. The influence of microwave power levels on the dried foams was investigated between 1 and 5 W/g. Intermediate microwave power settings led to the highest nutritional values, a colour appearance comparable to the undried foam and a proper wettability. A proper process stability could also be guaranteed for these power levels. By the volumetric energy input of the microwaves drying time could be reduced from 24 h in conventional freeze drying to about 6 h. The short drying times further resulted in an equally high maintenance of the above mentioned parameters in both drying techniques. Hence, microwave assisted freeze drying could lead to a process acceleration in comparison to freeze drying and be therefore an interesting alternative drying technique which on industrial scale enables higher efficiency and higher product throughput.

Keywords: foam drying, freeze drying, fruit puree, microwave freeze drying, raspberry

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Authors: S. Y. Lin, C. H. Kuan, C. H. She, W. T. Wang

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In this study, ultrasonic assisted machining (UAM) technique is applied in side-surface milling experiment for glass-ceramic workpiece material. The tungsten carbide cutting-tool with diamond coating is used in conjunction with two kinds of cooling/lubrication mediums such as water-soluble (WS) cutting fluid and minimum quantity lubricant (MQL). Full factorial process parameter combinations on the milling experiments are planned to investigate the effect of process parameters on cutting performance. From the experimental results, it tries to search for the better process parameter combination which the edge-indentation and the surface roughness are acceptable. In the machining experiments, ultrasonic oscillator was used to excite a cutting-tool along the radial direction producing a very small amplitude of vibration frequency of 20KHz to assist the machining process. After processing, toolmaker microscope was used to detect the side-surface morphology, edge-indentation and cutting tool wear under different combination of cutting parameters, and analysis and discussion were also conducted for experimental results. The results show that the main leading parameters to edge-indentation of glass ceramic are cutting depth and feed rate. In order to reduce edge-indentation, it needs to use lower cutting depth and feed rate. Water-soluble cutting fluid provides a better cooling effect in the primary cutting area; it may effectively reduce the edge-indentation and improve the surface morphology of the glass ceramic. The use of ultrasonic assisted technique can effectively enhance the surface finish cleanness and reduce cutting tool wear and edge-indentation.

Keywords: glass-ceramic, ultrasonic assisted machining, cutting performance, edge-indentation

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Authors: Z. Olczykowski

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The paper presents the impact of work on the electric arc furnace. Arc equipment is one of the largest receivers powered by the power system. Electric arc disturbances arising during melting process occurring in these furnaces are the cause of an abrupt change of the passive power of furnaces. Currents drawn by these devices undergo an abrupt change, which in turn cause voltage fluctuations and light flicker. The quantitative evaluation of the voltage fluctuations is now the basic criterion of assessment of an influence of unquiet receiver on the supplying net. The paper presents the method of determination of range of voltage fluctuations and light flicker at parallel operation of arc devices. The results of measurements of voltage fluctuations and light flicker indicators recorded in power supply networks of steelworks were presented, with different number of parallel arc devices. Measurements of energy quality parameters were aimed at verifying the proposed method in practice. It was also analyzed changes in other parameters of electricity: the content of higher harmonics, asymmetry, voltage dips.

Keywords: power quality, arc furnaces, propagation of voltage fluctuations, disturbances

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Authors: Y. T. Tsai, Jin H. Huang

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The sound pressure level (SPL) of the moving-coil loudspeaker (MCL) is often simulated and analyzed using the lumped parameter model. However, the SPL of a MCL cannot be simulated precisely in the high frequency region, because the value of cone effective area is changed due to the geometry variation in different mode shapes, it is also related to affect the acoustic radiation mass and resistance. Herein, the paper presents the inverse method which has a high ability to measure the value of cone effective area in various frequency points, also can estimate the MCL electroacoustic parameters simultaneously. The proposed inverse method comprises the direct problem, adjoint problem, and sensitivity problem in collaboration with nonlinear conjugate gradient method. Estimated values from the inverse method are validated experimentally which compared with the measured SPL curve result. Results presented in this paper not only improve the accuracy of lumped parameter model but also provide the valuable information on loudspeaker cone design.

Keywords: inverse problem, cone effective area, loudspeaker, nonlinear conjugate gradient method

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Authors: Anugrah Tripathi, H. S. Ginwal, Charul Kainthola

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Bamboos are considered as valuable resources which have the potential of meeting current economic, environmental and social needs. Bamboo has played a key role in humankind and its livelihood since ancient time. Distributed in diverse areas across the globe, bamboo makes an important natural resource for hundreds of millions of people across the world. In some of the Asian countries and northeast part of India, bamboo is the basis of life on many horizons. India possesses the largest bamboo-bearing area across the world and a great extent of species richness, but this rich genetic resource and its diversity have dwindled in the natural forest due to forest fire, over exploitation, lack of proper management policies, and gregarious flowering behavior. Bamboos which are well known for their peculiar, extraordinary morphology, show a lot of variation in many scales. Among the various bamboo species, Dendrocalamus strictus is the most abundant bamboo resource in India, which is a deciduous, solid, and densely tufted bamboo. This species can thrive in wide gradients of geographical as well as climatic conditions. Due to this, it exhibits a significant amount of variation among the populations of different origins for numerous morphological features. Morphological parameters are the front-line criteria for the selection and improvement of any forestry species. Study on the diversity among eight important morphological characters of D. strictus was carried out, covering 16 populations from wide geographical locations of India following INBAR standards. Among studied 16 populations, three populations viz. DS06 (Gaya, Bihar), DS15 (Mirzapur, Uttar Pradesh), and DS16 (Bhogpur, Pinjore, Haryana) were found as superior populations with higher mean values for parametric characters (clump height, no. of culms/ clump, circumference of clump, internode diameter and internode length) and with the higher sum of ranks in non-parametric characters (straightness, disease, and pest incidence and branching pattern). All of these parameters showed an ample amount of variations among the studied populations and revealed a significant difference among the populations. Variation in morphological characters is very common in a species having wide distribution and is usually evident at various levels, viz., between and within the populations. They are of paramount importance for growth, biomass, and quick production gains. Present study also gives an idea for the selection of the population on the basis of these morphological parameters. From this study on morphological parameters and their variation, we may find an overview of best-performing populations for growth and biomass accumulation. Some of the studied parameters also provide ideas to standardize mechanisms of selecting and sustainable harvesting of the clumps by applying simpler silvicultural systems so that they can be properly managed in homestead gardens for the community utilization as well as by commercial growers to meet the requirement of industries and other stakeholders.

Keywords: Dendrocalamus strictus, homestead garden, gregarious flowering, stakeholders, INBAR

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Authors: Maria C. Proença, Maria T. Rebelo, Marília Antunes, Maria J. Alves, Hugo Osório, Sofia Cunha, João Casaca

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Using a geographic information system (GIS), the relations between a georeferenced data set of Culex pipiens sl. mosquitoes collected in Portugal mainland during seven years (2006-2012) and meteorological and physiographic parameters such as: air relative humidity, air temperature (minima, maxima and mean daily temperatures), daily total rainfall, altitude, land use/land cover and proximity to water bodies are evaluated. Focus is on the mosquito females; the characterization of its habitat is the key for the planning of chirurgical non-aggressive prophylactic countermeasures to avoid ambient degradation. The GIS allow for the spatial determination of the zones were the mosquito mean captures has been above average; using the meteorological values at these coordinates, the limits of each parameter are identified/computed. The meteorological parameters measured at the net of weather stations all over the country are averaged by month and interpolated to produce raster maps that can be segmented according to the thresholds obtained for each parameter. The intersection of the maps obtained for each month show the evolution of the area favorable to the species through the mosquito season, which is from May to October at these latitudes. In parallel, mean and above average captures were related to the physiographic parameters. Three levels of risk could be identified for each parameter, using above average captures as an index. The results were applied to the suitability meteorological maps of each month. The Culex pipiens critical niche is delimited, reflecting the critical areas and the level of risk for transmission of the pathogens to which they are competent vectors (West Nile virus, iridoviruses, rheoviruses and parvoviruses).

Keywords: Culex pipiens, ecological niche, risk assessment, risk management

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Authors: F. Kantaş, D. Boyacı, C. Dinç

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Exhaust systems plays an important role in thermal heat management. Exhaust manifold picks burned gas from engine and exhaust pipes transmit exhaust gas to muffler, exhaust gas is reacted chemically to avoid noxious gas and sound is reduced in muffler then gas is threw out with tail pipe from muffler. Exhaust gas flows out from tail pipe and this hot gas flows to many parts that available around tail pipe and muffler, like spare tire, transmission, pipes etc. These parts are heated by hot exhaust gas. Also vehicle on ride, external flow effects exhaust gas flow and exhaust gas behavior is changed. It's impossible to understand which parts are heated by hot exhaust gas in tests. To understand this phenomena, exhaust gas flow is solved in CFD also external flow due to vehicle movement must be solved with exhaust gas flow. Because external flow effects exhaust gas flow behavior with many parameters. This paper investigates external flow effects exhaust gas flow behavior and other critical parameters effect exhaust gas flow behavior, like different tail pipe design, exhaust gas mass flow in critic vehicle driving situations.

Keywords: exhaust, gas flow, vehicle, external flow

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Authors: Ajith J. Kings, L. R. Monisha Miriam, R. Edwin Raj, S. Julyes Jaisingh, S. Gavaskar

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Microalgae are a potential bio-source for rejuvenated solutions in various disciplines of science and technology, especially in medicine and energy. Biodiesel is being replaced for conventional fuels in automobile industries with reduced pollution and equivalent performance. Since it is a carbon neutral fuel by recycling CO2 in photosynthesis, global warming potential can be held in control using this fuel source. One of the ways to meet the rising demand of automotive fuel is to adopt with eco-friendly, green alternative fuels called sustainable microalgal biodiesel. In this work, a microalga Chlamydomonas reinhardtii was cultivated and optimized in different media compositions developed from under-utilized waste materials in lab scale. Using the optimized process conditions, they are then mass propagated in out-door ponds, harvested, dried and oils extracted for optimization in ambient conditions. The microalgal oil was subjected to two step esterification processes using acid catalyst to reduce the acid value (0.52 mg kOH/g) in the initial stage, followed by transesterification to maximize the biodiesel yield. The optimized esterification process parameters are methanol/oil ratio 0.32 (v/v), sulphuric acid 10 vol.%, duration 45 min at 65 ºC. In the transesterification process, commercially available alkali catalyst (KOH) is used and optimized to obtain a maximum biodiesel yield of 95.4%. The optimized parameters are methanol/oil ratio 0.33(v/v), alkali catalyst 0.1 wt.%, duration 90 min at 65 ºC 90 with smooth stirring. Response Surface Methodology (RSM) is employed as a tool for optimizing the process parameters. The biodiesel was then characterized with standard procedures and especially by GC-MS to confirm its compatibility for usage in internal combustion engine.

Keywords: microalgae, organic media, optimization, transesterification, characterization

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Authors: Anna Rogozińska-Pawełczyk

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A psychological contract is an agreement between the employer and an employee that covers the parties’ informal and frequently non-verbalized obligations and expectations towards each other. The contract is a cognitive pattern-governing employee’s behaviour in the organization. A gap between employee’s expectations and the organizational reality may lead to difficult-to-solve conflicts or cause the employee to modify their behaviour towards organizational values and goals, if they are willing and ready to verbalize their expectations. The article discusses psychological contracts in the financial institutions in Poland. Its theoretical part outlines the types of psychological contracts in organizations (relational, transactional, and balanced) and shows the process of their verbalization. The purpose of the article is to present how the type of the psychological contract relates to employee’s readiness to verbalize it. The article ends with conclusions arising from the study.

Keywords: customer contact staff in banks, employee expectations, financial institutions, mutual expectations, psychological contract, verbalization of the psychological contract

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Authors: Mumtaz Khan, Adeel Shahid, Waqas Khan

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Heavy metals presence in water streams is a big danger for aquatic life and ultimately effects human health. Removal of copper (Cu) by ispaghula husk, maize fibre, and maize oil cake from synthetic solution in batch conditions was studied. Different experimental parameters such as contact time, initial solution pH, agitation rate, initial Cu concentration, biosorbent concentration, and biosorbent particle size has been studied to quantify the Cu biosorption. The rate of adsorption of metal ions was very fast at the beginning and became slow after reaching the saturation point, followed by a slower active metabolic uptake of metal ions into the cells. Up to a certain point, (pH=4, concentration of Cu = ~ 640 mg/l, agitation rate = ~ 400 rpm, biosorbent concentration = ~ 0.5g, 3g, 3g for ispaghula husk, maize fiber and maize oil cake, respectively) increasing the pH, concentration of Cu, agitation rate, and biosorbent concentration, increased the biosorption rate; however the sorption capacity increased by decreasing the particle size. At optimized experimental parameters, the maximum Cu biosorption by ispaghula husk, maize fibre and maize oil cake were 86.7%, 59.6% and 71.3%, respectively. Moreover, the results of the kinetics studies demonstrated that the biosorption of copper on ispaghula husk, maize fibre, and maize oil cake followed pseudo-second order kinetics. The results of adsorption were fitted to both the Langmuir and Freundlich models. The Langmuir model represented the sorption process better than Freundlich, and R² value ~ 0.978. Optimizations of physical and environmental parameters revealed, ispaghula husk as more potent copper biosorbent than maize fibre, and maize oil cake. The sorbent is cheap and available easily, so this study can be applied to remove Cu impurities on pilot and industrial scale after certain modifications.

Keywords: biosorption, copper, ispaghula husk, maize fibre, maize oil cake, purification

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Authors: M. Zare, S. Biau, M. Corq, Y. Roquelaure

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A wide variety of observational methods have been developed to evaluate the ergonomic workloads in manufacturing. However, the precision and accuracy of these methods remain a subject of debate. The aims of this study were to develop biomechanical methods to evaluate ergonomic workloads and to compare them with observational methods. Two observational methods, i.e. SCANIA Ergonomic Standard (SES) and Rapid Upper Limb Assessment (RULA), were used to assess ergonomic workloads at two simulated workstations. They included four tasks such as tightening & loosening, attachment of tubes and strapping as well as other actions. Sensors were also used to measure biomechanical data (Inclinometers, Accelerometers, and Goniometers). Our findings showed that in assessment of some risk factors both RULA & SES were in agreement with the results of biomechanical methods. However, there was disagreement on neck and wrist postures. In conclusion, the biomechanical approach was more precise than observational methods, but some risk factors evaluated with observational methods were not measurable with the biomechanical techniques developed.

Keywords: ergonomic, observational method, biomechanical methods, workload

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Authors: Masoud Irannezhad, Sirpa Rasmus, Saghar Ahmadian, Deliang Chen, Bjorn Klove

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Variability and changes in thermal conditions play a crucial role in functioning of human society, particularly over cold climate regions like Finland. Accordingly, the frost-free season (FFS) parameters in terms of start (FFSS), end (FFSE) and length (FFSL) have substantial effects not only on natural environment (e.g. flora and fauna), but also on human requirements (e.g. agriculture, forestry and energy generation). Applying the 0°C threshold of minimum temperature (Tmin), the FFS was defined as the period between the last spring frost as FFSS and the first fall frost as FFSE. For this study, gridded (10 x 10 km2) daily minimum temperature datasets throughout Finland during 1961-2011 was used to investigate recent spatio-temporal variations and trends in frost-free season (FFS) parameters and their relationships with the well-known large-scale climate teleconnections (CTs). The FFS in Finland naturally increases from north (~60 days) to south (~190 days), in association with earlier FFSS (~24 April) and later FFSE (~30 October). Statistically significant (p<0.05) trends in FFSL were all positive (increasing) ranged between 0 and 13.5 (days/decade) and mainly observed in the east, upper west, centre and upper north of Finland. Such lengthening trends in FFS were attributable to both earlier FFSS and later FFSE mostly over central and upper northern Finland, while only to later FFSE in eastern and upper western parts. Variations in both FFSL and FFSS were significantly associated with the Polar (POL) pattern over northern Finland, while with the East Atlantic (EA) pattern over eastern and upper western areas. However, the POL and Scandinavia (SCA) patterns were most influential CTs for FFSE variability over northern Finland.

Keywords: climate teleconnections, Finland, frost-free season, trend analysis

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Authors: H. A. Mansour

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The objective of this research work is studying the water use prediction, prediction technology for water use by action agencies, and others involved in conservation, planning, and environmental assessment of the Water Erosion Prediction Project (WEPP) simulation model. Models the important physical, processes governing erosion in Egypt (climate, infiltration, runoff, ET, detachment by raindrops, detachment by flowing water, deposition, etc.). Simulation of the non-uniform slope, soils, cropping/management., and Egyptian databases for climate, soils, and crops. The study included important parameters in Egyptian conditions as follows: Water Balance & Percolation, Soil Component (Tillage impacts), Plant Growth & Residue Decomposition, Overland Flow Hydraulics. It could be concluded that we can adapt the WEPP simulation model to determining the previous important parameters under Egyptian conditions.

Keywords: WEPP, adaptation, soil properties, tillage impacts, water balance, soil percolation

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Authors: Xia Luo, Cheng Zeng

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Under the promotion of the Central Committee of the Communist Party of China and the State Council in 2017, Xiong'an New Area is the third crucial new area in China established after Shenzhen and Shanghai. Its constructions' significance lies in mitigating Beijing's non-capital functions and exploring a new mode of optimizing development in densely populated and economically intensive areas. For this purpose, developing underground logistics can assume the role of goods distribution in the capital, relieve the road transport pressure in Beijing-Tianjin-Hebei Urban Agglomeration, adjust and optimize the urban layout and spatial structure of it. Firstly, the construction planning of Xiong'an New Area and underground logistics development are summarized, especially the development status abroad, the development trend, and bottlenecks of underground logistics in China. This paper explores the technicality, feasibility, and necessity of four modes of transportation. There are pneumatic capsule pipeline (PCP) technology, the CargoCap technology, cable hauled mule, and automatic guided vehicle (AGV). The above technical parameters and characteristics are introduced to relevant experts or scholars. Through establishing an indicator system, carrying out a questionnaire survey with the Delphi method, the final suggestion is obtained: China should develop logistics vehicles similar to CargoCap, adopting rail mode and driverless mode. Based on China's temporal and spatial logistics demand and the geographical pattern of Xiong'an New Area, the construction scale, technical parameters, node location, and other vital parameters of underground logistics are planned. In this way, we hope to speed up the new area's construction and the logistics industry's innovation.

Keywords: the Xiong'an new area, underground logistics, contrastive analysis, CargoCap, logistics planning

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Authors: Jungbin Lim, Bohee Kang, Heelim Lee, Sunjin Kim, GeumHee Choi, Jae-Suk Jung, Suk Ji

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Nonsurgical periodontal therapies have, for several decades, been the basis of periodontal treatment concepts. The aim of this paper is to investigate the effectiveness of non-surgical periodontal therapy according to the severity of periodontitis disease. Methods: Retrospective data of patients who visited Department of periodontics in Ajou University Medical Center from 2016 to 2022 were collected. Among the patients, those who took full mouth examination of clinical parameters and non-surgical periodontal therapy were chosen for this study. Selected patients were divided into initial, moderate, and severe periodontitis based on severity and complexity of management (2018 World Workshop EFP/AAP consensus). Recall visits with clinical periodontal examination were scheduled for 1,2,3 months or 1,3,6 months after the treatment. The results were evaluated by recordings of mean probing pocket depth (mean PD), mean clinical attachment levels (mean CAL), bleeding on probing (BOP%), mean gingival index (mean GI), mean regression, mean sulcus bleeding index (mean SBI), mean plaque scores (mean PI). All statistical analyses were performed with R software, version 4.3.0. A level of significance, P<0.05, was considered to be statistically significant. Results: A total of 92 patients were included in this study. 15 patients were diagnosed as initial periodontitis, 14 moderate periodontitis, and 63 severe periodontitis. The all parameters except for mean recession decreased over time in all groups. The amount of mean PD decreased were the greatest in severe periodontitis group followed by moderate and initial, which was found to be statistically significant. The changes of mean PD were 0.15±0.05 mm, 0.37±0.06 mm, and 1.01±0.07 mm (initial, moderate, and severe, respectively, P<0.001). When comparing before and after treatment, the reductions in BOP(%), mean GI, mean SBI, and mean PI were statistically significant. Conclusion: All patients who received non-surgical periodontal therapy showed periodontal healing in terms of improvements in clinical parameters, and it was greater in the severe group.

Keywords: periodontology, clinical periodontology, oral treatment, comprehensive preventive dentistry, non-surgical periodontal therapy

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Authors: Nurul Na'imy Wan, Mohamad Sazali Said, Jaharah Ab. Ghani, Mohd Asri Selamat

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This paper presents the surface roughness of the Aluminium silicon alloy (AlSi) matrix composite which has been reinforced with aluminium nitride (AlN), with three types of carbide inserts. Experiments were conducted at various cutting speeds, feed rates, and depths of cut, according to the Taguchi method, using a standard orthogonal array L27 (34). The signal-to-noise (S/N) ratio and analysis of variance are applied to study the characteristic performance of machining parameters in measuring the surface roughness during the milling operation. The analysis of results, using the Taguchi method concluded that a combination of low feed rate, medium depth of cut, low cutting speed, and insert TiB2 give a better value of surface roughness. From Taguchi method, it was found that cutting speed of 230m/min, feed rate of 0.4 mm/tooth, depth of cut of 0.5mm and type of insert of TiB2 were the optimal machining parameters that gave the optimal value of surface roughness.

Keywords: AlSi/AlN Metal Matrix Composite (MMC), surface roughness, Taguchi method

Procedia PDF Downloads 453

Authors: Elizabeth Hoyos, Hernán Alvarez, Diana Lopez, Yesid Montoya

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The main goal of this research relates to the modeling of FSW from a different or unusual perspective coming from mechanical engineering, particularly looking for a way to establish process windows by assessing soundness of the joints as a priority and with the added advantage of lower computational time. This paper presents the use of a previously developed model applied to specific aspects of soundness evaluation of AA7075 FSW welds. EMSO software (Environment for Modeling, Simulation, and Optimization) was used for simulation and an adapted CNC machine was used for actual welding. This model based approach showed good agreement with the experimental data, from which it is possible to set a window of operation for commercial aluminum alloy AA7075, all with low computational costs and employing simple quality indicators that can be used by non-specialized users in process modeling.

Keywords: aluminum AA7075, friction stir welding, phenomenological based semiphysical model, processing map

Procedia PDF Downloads 251

Authors: Felipe M. de Freitas, Icaro V. Soares, Lucas L. L. Fortes, Sandro T. M. Gonçalves, Úrsula D. C. Resende

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The SPICE-based simulators are quite robust and widely used for simulation of electronic circuits, their algorithms support linear and non-linear lumped components and they can manipulate an expressive amount of encapsulated elements. Despite the great potential of these simulators based on SPICE in the analysis of quasi-static electromagnetic field interaction, that is, at low frequency, these simulators are limited when applied to microwave hybrid circuits in which there are both lumped and distributed elements. Usually the spatial discretization of the FDTD (Finite-Difference Time-Domain) method is done according to the actual size of the element under analysis. After spatial discretization, the Courant Stability Criterion calculates the maximum temporal discretization accepted for such spatial discretization and for the propagation velocity of the wave. This criterion guarantees the stability conditions for the leapfrogging of the Yee algorithm; however, it is known that for the field update, the stability of the complete FDTD procedure depends on factors other than just the stability of the Yee algorithm, because the FDTD program needs other algorithms in order to be useful in engineering problems. Examples of these algorithms are Absorbent Boundary Conditions (ABCs), excitation sources, subcellular techniques, grouped elements, and non-uniform or non-orthogonal meshes. In this work, the influence of the stability of the FDTD method in the modeling of concentrated elements such as resistive sources, resistors, capacitors, inductors and diode will be evaluated. In this paper is proposed, therefore, the electromagnetic modeling of electronic components in order to create models that satisfy the needs for simulations of circuits in ultra-wide frequencies. The models of the resistive source, the resistor, the capacitor, the inductor, and the diode will be evaluated, among the mathematical models for lumped components in the LE-FDTD method (Lumped-Element Finite-Difference Time-Domain), through the parametric analysis of Yee cells size which discretizes the lumped components. In this way, it is sought to find an ideal cell size so that the analysis in FDTD environment is in greater agreement with the expected circuit behavior, maintaining the stability conditions of this method. Based on the mathematical models and the theoretical basis of the required extensions of the FDTD method, the computational implementation of the models in Matlab® environment is carried out. The boundary condition Mur is used as the absorbing boundary of the FDTD method. The validation of the model is done through the comparison between the obtained results by the FDTD method through the electric field values and the currents in the components, and the analytical results using circuit parameters.

Keywords: hybrid circuits, LE-FDTD, lumped element, parametric analysis

Procedia PDF Downloads 142

Authors: Peter O. Osifo, Hein W. J. P. Neomagus, Hein V. D. Merwe

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Chitosan materials from different sources of raw materials were characterized in order to determine optimal preparation conditions and parameters for membrane production. The membrane parameters such as molecular weight, viscosity, and degree of deacetylation were used to evaluate the membrane performance for zinc ion adsorption. The molecular weight of the chitosan was found to influence the viscosity of the chitosan/acetic acid solution. An increase in molecular weight (60000-400000 kg.kmol-1) of the chitosan resulted in a higher viscosity (0.05-0.65 Pa.s) of the chitosan/acetic acid solution. The effect of the degree of deacetylation on the viscosity is not significant. The effect of the membrane production parameters (chitosan- and acetic acid concentration) on the viscosity is mainly determined by the chitosan concentration. For higher chitosan concentrations, a membrane with a better adsorption capacity was obtained. The membrane adsorption capacity increases from 20-130 mg Zn per gram of wet membrane for an increase in chitosan concentration from 2-7 mass %. Chitosan concentrations below 2 and above 7.5 mass % produced membranes that lack good mechanical properties. The optimum manufacturing conditions including chitosan concentration, acetic acid concentration, sodium hydroxide concentration and crosslinking for chitosan membranes within the workable range were defined by the criteria of adsorption capacity and flux. The adsorption increases (50-120 mg.g-1) as the acetic acid concentration increases (1-7 mass %). The sodium hydroxide concentration seems not to have a large effect on the adsorption characteristics of the membrane however, a maximum was reached at a concentration of 5 mass %. The adsorption capacity per gram of wet membrane strongly increases with the chitosan concentration in the acetic acid solution but remains constant per gram of dry chitosan. The optimum solution for membrane production consists of 7 mass % chitosan and 4 mass % acetic acid in de-ionised water. The sodium hydroxide concentration for phase inversion is at optimum at 5 mass %. The optimum cross-linking time was determined to be 6 hours (Percentage crosslinking of 18%). As the cross-linking time increases the adsorption of the zinc decreases (150-50 mg.g-1) in the time range of 0 to 12 hours. After a crosslinking time of 12 hours, the adsorption capacity remains constant. This trend is comparable to the effect on flux through the membrane. The flux decreases (10-3 L.m-2.hr-1) with an increase in crosslinking time range of 0 to 12 hours and reaches a constant minimum after 12 hours.

Keywords: chitosan, membrane, waste water, heavy metal ions, adsorption

Procedia PDF Downloads 368

Authors: Muna F. Al-Sammaraie

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The aim of this research is to present a multi spectral image enhancement methods used to achieve highly real digital image populates only a small portion of the available range of digital values. Also, a quantitative measure of image enhancement is presented. This measure is related with concepts of the Webers Low of the human visual system. For decades, several image enhancement techniques have been proposed. Although most techniques require profuse amount of advance and critical steps, the result for the perceive image are not as satisfied. This study involves changing the original values so that more of the available range is used; then increases the contrast between features and their backgrounds. It consists of reading the binary image on the basis of pixels taking them byte-wise and displaying it, calculating the statistics of an image, automatically enhancing the color of the image based on statistics calculation using algorithms and working with RGB color bands. Finally, the enhanced image is displayed along with image histogram. A number of experimental results illustrated the performance of these algorithms. Particularly the quantitative measure has helped to select optimal processing parameters: the best parameters and transform.

Keywords: image enhancement, multi-spectral, RGB, histogram

Procedia PDF Downloads 319

Authors: Zoi Konsoula

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Vegetable oils, which are rich in polyunsaturated fatty acids, are susceptible to oxidative deterioration. The lipid oxidation of oils results in the production of rancid odors and unpleasant flavors as well as the reduction of their nutritional quality and safety. Traditionally, synthetic antioxidants are employed for their retardation or prevention of oxidative deterioration of oils. However, these compounds are suspected to pose health hazards. Consequently, recently there has been a growing interest in the use of natural antioxidants of plant origin for improving the oxidative stability of vegetable oils. The genus Salvia (sage) is well known for its antioxidant activity. In the Cypriot flora Salvia fruticosa is the most distributed indigenous Salvia species. In the present study, extracts were prepared from S. fruticosa aerial parts using various solvents and their antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging and Ferric Reducing Antioxidant Power (FRAP) method. Moreover, the antioxidant efficacy of all extracts was assessed using corn oil as the oxidation substrate, which was subjected to accelerated aging (60 °C, 30 days). The progress of lipid oxidation was monitored by the determination of the peroxide, p-aniside, conjugated dienes and trienes value according to the official AOCS methods. Synthetic antioxidants (butylated hydroxytoluene-BHT and butylated hydroxyanisole-BHA) were employed at their legal limit (200 ppm) as reference. Finally, the total phenolic (TPC) and flavonoid content (TFC) of the prepared extracts was measured by the Folin-Ciocalteu and aluminum-flavonoid complex method, respectively. The results of the present study revealed that although all sage extracts prepared from S. fruticosa exhibited antioxidant activity, the highest antioxidant capacity was recorded in the methanolic extract, followed by the non-toxic, food grade ethanol. Furthermore, a positive correlation between the antioxidant potency and the TPC of extracts was observed in all cases. Interestingly, sage extracts prevented lipid oxidation in corn oil at all concentrations tested, however, the magnitude of stabilization was dose dependent. More specifically, results from the different oxidation parameters were in agreement with each other and indicated that the protection offered by the various extracts depended on their TPC. Among the extracts, the methanolic extract was more potent in inhibiting oxidative deterioration. Finally, both methanolic and ethanolic sage extracts at a concentration of 1000 ppm exerted a stabilizing effect comparable to that of the reference synthetic antioxidants. Based on the results of the present study, sage extracts could be used for minimizing or preventing lipid oxidation in oils and, thus, prolonging their shelf-life. In particular, given that the use of dietary alcohol, such as ethanol, is preferable than methanol in food applications, the ethanolic extract prepared from S. fruticosa could be used as an alternative natural antioxidant.

Keywords: antioxidant activity, corn oil, oxidative deterioration, sage

Procedia PDF Downloads 185

Authors: Mehrnaz Alibeikloo, Hajar Share Isfahani, Hadi Khabbaz

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In recent years, by developing cities and increasing population, reconstructing on closed landfill sites in some regions is unavoidable. Long-term settlement is one of the major concerns associated with reconstruction on landfills after closure. The purpose of this research is evaluating the effect of preloading in various patterns of height and time on long-term settlements of closed landfills. In this regard, five scenarios of surcharge from 1 to 3 m high within 3, 4.5 and 6 months of preloading time have been modeled using PLAXIS 2D software. Moreover, the numerical results have been compared to those obtained from analytical methods, and a good agreement has been achieved. The findings indicate that there is a linear relationship between settlement and surcharge height. Although, long-term settlement decreased by applying a longer and higher preloading, the time of preloading was found to be a more effective factor compared to preloading height.

Keywords: preloading, long-term settlement, landfill, PLAXIS 2D

Procedia PDF Downloads 181