Search results for: Small Tanks

Authors: T. Maruyama, T. Saida, S. Naritsuka, S. Iijima

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Single-walled carbon nanotubes (SWCNTs) are generally synthesized by chemical vapor deposition (CVD) using Fe, Co, and Ni as catalysts. However, due to the Ostwald ripening of metal catalysts, the diameter distribution of the grown SWCNTs is considerably wide (>2 nm), which is not suitable for electronics applications. In addition, reduction in the growth temperature is desirable for fabricating SWCNT devices compatible with the LSI process. Herein, we performed SWCNT growth by alcohol catalytic CVD using platinum-group metal catalysts (Pt, Rh, and Pd) because these metals have high melting points, and the reduction in the Ostwald ripening of catalyst particles is expected. Our results revealed that web-like SWCNTs were obtained from Pt and Rh catalysts at growth temperature between 500 °C and 600 °C by optimizing the ethanol pressure. The SWCNT yield from Pd catalysts was considerably low. By decreasing the growth temperature, the diameter and chirality distribution of SWCNTs from Pt and Rh catalysts became small and narrow. In particular, the diameters of most SWCNTs grown using Pt catalysts were below 1 nm and their diameter distribution was considerably narrow. On the contrary, SWCNTs can grow from Rh catalysts even at 300 °C by optimizing the growth condition, which is the lowest temperature recorded for SWCNT growth. Our results demonstrated that platinum-group metals are useful for the growth of small-diameter SWCNTs and facilitate low-temperature growth.

Keywords: Carbon nanotube, chemical vapor deposition, catalyst, Pt, Rh, Pd.

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Authors: Gideon J. Bonthuys, Marco van Dijk, Jay N. Bhagwan

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Small scale hydropower used to play a very important role in the provision of energy to urban and rural areas of South Africa. The national electricity grid, however, expanded and offered cheap, coal generated electricity and a large number of hydropower systems were decommissioned. Unfortunately, large numbers of households and communities will not be connected to the national electricity grid for the foreseeable future due to high cost of transmission and distribution systems to remote communities due to the relatively low electricity demand within rural communities and the allocation of current expenditure on upgrading and constructing of new coal fired power stations. This necessitates the development of feasible alternative power generation technologies. A feasibility and implementation model was developed to assist in designing and financially evaluating small-scale hydropower (SSHP) plants. Several sites were identified using the model. The SSHP plants were designed for the selected sites and the designs for the different selected sites were priced using pricing models (civil, mechanical and electrical aspects). Following feasibility studies done on the designed and priced SSHP plants, a feasibility analysis was done and a design chart developed for future similar potential SSHP plant projects. The methodology followed in conducting the feasibility analysis for other potential sites consisted of developing cost and income/saving formulae, developing net present value (NPV) formulae, Capital Cost Comparison Ratio (CCCR) and levelised cost formulae for SSHP projects for the different types of plant installations. It included setting up a model for the development of a design chart for a SSHP, calculating the NPV, CCCR and levelised cost for the different scenarios within the model by varying different parameters within the developed formulae, setting up the design chart for the different scenarios within the model and analyzing and interpreting results. From the interpretation of the develop design charts for feasible SSHP in can be seen that turbine and distribution line cost are the major influences on the cost and feasibility of SSHP. High head, short transmission line and islanded mini-grid SSHP installations are the most feasible and that the levelised cost of SSHP is high for low power generation sites. The main conclusion from the study is that the levelised cost of SSHP projects indicate that the cost of SSHP for low energy generation is high compared to the levelised cost of grid connected electricity supply; however, the remoteness of SSHP for rural electrification and the cost of infrastructure to connect remote rural communities to the local or national electricity grid provides a low CCCR and renders SSHP for rural electrification feasible on this basis.

Keywords: Feasibility, cost, rural electrification, small-scale hydropower.

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Authors: Amir Sattari

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For newly produced houses and energy renovations, an energy calculation needs to be conducted. This is done to verify whether the energy consumption criteria of the house -to reach the energy targets by 2020 and 2050- are in-line with the norms. The main purpose of this study is to confirm whether easy to use energy calculation software or hand calculations used by small companies or individuals give logical results compared to advanced energy simulation program used by researchers or bigger companies. There are different methods for calculating energy consumption. In this paper, two energy calculation programs are used and the relation of energy consumption with solar radiation is compared. A hand calculation is also done to validate whether the hand calculations are still reasonable. The two computer programs which have been used are TMF Energi (the easy energy calculation variant used by small companies or individuals) and IDA ICE - Indoor Climate and Energy (the advanced energy simulation program used by researchers or larger companies). The calculations are done for a standard house from the Swedish house supplier Fiskarhedenvillan. The method is based on having the same conditions and inputs in the different calculation forms so that the results can be compared and verified. The house has been faced differently to see how the orientation affects energy consumption in different methods. The results for the simulations are close to each other and the hand calculation differs from the computer programs by only 5%. Even if solar factors differ due to the orientation of the house, energy calculation results from different computer programs and even hand calculation methods are in line with each other.

Keywords: Energy calculation, energy consumption, energy simulation, IDA ICE, TMF Energi.

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Authors: Mohanad Alhabo, Li Zhang, Naveed Nawaz

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Small cell deployment in 5G networks is a promising technology to enhance the capacity and coverage. However, unplanned deployment may cause high interference levels and high number of unnecessary handovers, which in turn result in an increase in the signalling overhead. To guarantee service continuity, minimize unnecessary handovers and reduce signalling overhead in heterogeneous networks, it is essential to properly model the handover decision problem. In this paper, we model the handover decision problem using Multiple Attribute Decision Making (MADM) method, specifically Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), and propose a hybrid TOPSIS method to control the handover in heterogeneous network. The proposed method adopts a hybrid weighting policy, which is a combination of entropy and standard deviation. A hybrid weighting control parameter is introduced to balance the impact of the standard deviation and entropy weighting on the network selection process and the overall performance. Our proposed method show better performance, in terms of the number of frequent handovers and the mean user throughput, compared to the existing methods.

Keywords: Handover, HetNets, interference, MADM, small cells, TOPSIS, weight.

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Authors: Haifeng Wang, Haili Zhang

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Most movie recommendation systems have been developed for customers to find items of interest. This work introduces a predictive model usable by small and medium-sized enterprises (SMEs) who are in need of a data-based and analytical approach to stock proper movies for local audiences and retain more customers. We used classification models to extract features from thousands of customers’ demographic, behavioral and social information to predict their movie genre preference. In the implementation, a Gaussian kernel support vector machine (SVM) classification model and a logistic regression model were established to extract features from sample data and their test error-in-sample were compared. Comparison of error-out-sample was also made under different Vapnik–Chervonenkis (VC) dimensions in the machine learning algorithm to find and prevent overfitting. Gaussian kernel SVM prediction model can correctly predict movie genre preferences in 85% of positive cases. The accuracy of the algorithm increased to 93% with a smaller VC dimension and less overfitting. These findings advance our understanding of how to use machine learning approach to predict customers’ preferences with a small data set and design prediction tools for these enterprises.

Keywords: Computational social science, movie preference, machine learning, SVM.

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Authors: M. W. Lau, C. O. Ng

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This is a study on numerical simulation of the convection-diffusion transport of a chemical species in steady flow through a small-diameter tube, which is lined with a very thin layer made up of retentive and absorptive materials. The species may be subject to a first-order kinetic reversible phase exchange with the wall material and irreversible absorption into the tube wall. Owing to the velocity shear across the tube section, the chemical species may spread out axially along the tube at a rate much larger than that given by the molecular diffusion; this process is known as dispersion. While the long-time dispersion behavior, well described by the Taylor model, has been extensively studied in the literature, the early development of the dispersion process is by contrast much less investigated. By early development, that means a span of time, after the release of the chemical into the flow, that is shorter than or comparable to the diffusion time scale across the tube section. To understand the early development of the dispersion, the governing equations along with the reactive boundary conditions are solved numerically using the Flux Corrected Transport Algorithm (FCTA). The computation has enabled us to investigate the combined effects on the early development of the dispersion coefficient due to the reversible and irreversible wall reactions. One of the results is shown that the dispersion coefficient may approach its steady-state limit in a short time under the following conditions: (i) a high value of Damkohler number (say Da ≥ 10); (ii) a small but non-zero value of absorption rate (say Γ* ≤ 0.5).

Keywords: Dispersion coefficient, early development of dispersion, FCTA, wall reactions.

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Authors: Shaila Ahmed, Raghu Prasad Rao Metpally, Sreedhara Sangadala, Boojala Vijay B Reddy

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Bone growth factors, such as Bone Morphogenic Protein-2 (BMP-2) have been approved by the FDA to replace grafting for some surgical interventions, but the high dose requirement limits its use in patients. Noggin, an extracellular protein, blocks the effect of BMP-2 by binding to BMP. Preventing the BMP-2/noggin interaction will help increase the free concentration of BMP-2 and therefore should enhance its efficacy to induce bone formation. The work presented here involves computational design of novel small molecule inhibitory agents of BMP-2/noggin interaction, based on our current understanding of BMP-2, and its known putative ligands (receptors and antagonists). A successful acquisition of such an inhibitory agent of BMP-2/noggin interaction would allow clinicians to reduce the dose required of BMP-2 protein in clinical applications to promote osteogenesis. The available crystal structures of the BMPs, its receptors, and the binding partner noggin were analyzed to identify the critical residues involved in their interaction. In presenting this study, LUDI de novo design method was utilized to perform virtual screening of a large number of compounds from a commercially available library against the binding sites of noggin to identify the lead chemical compounds that could potentially block BMP-noggin interaction with a high specificity.

Keywords: Transforming growth factor-beta, Bone morphogenic proteins, Noggin, LUDI de novo design method, CAP small molecules.

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Authors: Talam K. E, Kainkwa R. M.

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In this study, a field testing has been carried out to assess the power characteristics of some small scale wind turbines fabricated by one native technician from Tanzania. Two Horizontal Axis Wind Turbines (HAWTs), one with five and other with sixteen blades were installed at a height of 2.4m above the ground. The rotation speed of the rotor blade and wind speed approaching the turbines were measured simultaneously. The data obtained were used to determine how the power coefficient varies as a function of tip speed ratio and also the way in which the output power compares with available power in the wind for each turbine. For the sixteen-bladed wind turbine the maximum value of power coefficient of about 0.14 was found to occur at a tip speed ratio of around 0.65 while for the five bladed, these extreme values were respectively attained at approximately 0.2 and 1.7. The five bladed-wind turbine was found to have a higher power efficiency of about 37.5% which is higher compared to the sixteen bladed wind turbine whose corresponding value was 14.37%. This is what would be expected, as the smaller the number of blades of a wind turbine, the higher the electric power efficiency and vice versa. Some of the main reasons for the low efficiency of these machines may be due to the low aerodynamic efficiency of the turbine or low efficiency of the transmission mechanisms such as gearbox and generator which were not examined in this study. It is recommended that some other researches be done to investigate the power efficiency of such machines from different manufacturers in the country. The manufacturers should also be encouraged to use fewer blades in their designs so as to improve the efficiency and at the same time reduce materials used to fabricate the blades. The power efficiency of the electric generators used in the locally fabricated wind turbines should also be examined.

Keywords: Tip speed ratio, Power coefficients and power efficiency.

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Authors: Arkady Bolotin

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Dichotomization of the outcome by a single cut-off point is an important part of various medical studies. Usually the relationship between the resulted dichotomized dependent variable and explanatory variables is analyzed with linear regression, probit regression or logistic regression. However, in many real-life situations, a certain cut-off point dividing the outcome into two groups is unknown and can be specified only approximately, i.e. surrounded by some (small) uncertainty. It means that in order to have any practical meaning the regression model must be robust to this uncertainty. In this paper, we show that neither the beta in the linear regression model, nor its significance level is robust to the small variations in the dichotomization cut-off point. As an alternative robust approach to the problem of uncertain medical categories, we propose to use the linear regression model with the fuzzy membership function as a dependent variable. This fuzzy membership function denotes to what degree the value of the underlying (continuous) outcome falls below or above the dichotomization cut-off point. In the paper, we demonstrate that the linear regression model of the fuzzy dependent variable can be insensitive against the uncertainty in the cut-off point location. In the paper we present the modeling results from the real study of low hemoglobin levels in infants. We systematically test the robustness of the binomial regression model and the linear regression model with the fuzzy dependent variable by changing the boundary for the category Anemia and show that the behavior of the latter model persists over a quite wide interval.

Keywords: Categorization, Uncertain medical categories, Binomial regression model, Fuzzy dependent variable, Robustness.

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Authors: Sahila Chopra, Hemdeep, Arshdeep Kaur, Raj K. Gupta

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In recent times, we noticed an interesting and important role of non-coplanar degree-of-freedom (Φ = 00) in heavy ion reactions. Using the dynamical cluster-decay model (DCM) with Φ degree-of-freedom included, we have studied three compound systems 246Bk∗, 164Yb∗ and 105Ag∗. Here, within the DCM with pocket formula for nuclear proximity potential, we look for the effects of including compact, non-coplanar configurations (Φc = 00) on the non-compound nucleus (nCN) contribution in total fusion cross section σfus. For 246Bk∗, formed in 11B+235U and 14N+232Th reaction channels, the DCM with coplanar nuclei (Φc = 00) shows an nCN contribution for 11B+235U channel, but none for 14N+232Th channel, which on including Φ gives both reaction channels as pure compound nucleus decays. In the case of 164Yb∗, formed in 64Ni+100Mo, the small nCN effects for Φ=00 are reduced to almost zero for Φ = 00. Interestingly, however, 105Ag∗ for Φ = 00 shows a small nCN contribution, which gets strongly enhanced for Φ = 00, such that the characteristic property of PCN presents a change of behaviour, like that of a strongly fissioning superheavy element to a weakly fissioning nucleus; note that 105Ag∗ is a weakly fissioning nucleus and Psurv behaves like one for a weakly fissioning nucleus for both Φ = 00 and Φ = 00. Apparently, Φ is presenting itself like a good degree-of-freedom in the DCM.

Keywords: Dynamical cluster-decay model, fusion cross sections, non-compound nucleus effects, non-coplanarity.

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Authors: Md A. Hossain, Shabab M. Chowdhury, Yamin Rekhu, Khandakar S. Faraz, Monzur Ul Islam

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With the growth of modern civilization and industrialization in worldwide, the demand for energy is increasing day by day. Majority of the world-s energy needs are met through fossil fuels and natural gas. As a result the amount of fossil fuels is on diminishing from year to year. Since the fossil fuel is nonrenewable, so fuel price is gouging as a consequence of spiraling demand and diminishing supply. At present the power generation of our country is mainly depends on imported fossil fuels. To reduce the dependency on imported fuel, the use of renewable sources has become more popular. In Bangladesh coconut is widely growing tree. Especially in the southern part of the country a large area will be found where coconut tree is considered as natural asset. So, our endeavor was to use the coconut oil as a renewable and alternative fuel. This article shows the prospect of coconut oil as a renewable and alternative fuel of diesel fuel. Since diesel engine has a versatile uses including small electricity generation, an experimental set up is then made to study the performance of a small diesel engine using different blends of bio diesel converted from coconut oil. It is found that bio diesel has slightly different properties than diesel. With biodiesel the engine is capable of running without difficulty. Different blends of bio diesel (i.e. B80, B60, and B 50 etc.) have been used to avoid complicated modification of the engine or the fuel supply system. Finally, a comparison of engine performance for different blends of biodiesel has been carried out to determine the optimum blend for different operating conditions.

Keywords: Biodiesel, Bio-fuel, Renewable Energy, Transesterification

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Authors: A. T. Eswara

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This paper analyses the unsteady, two-dimensional stagnation point flow of an incompressible viscous fluid over a flat sheet when the flow is started impulsively from rest and at the same time, the sheet is suddenly stretched in its own plane with a velocity proportional to the distance from the stagnation point. The partial differential equations governing the laminar boundary layer forced convection flow are non-dimensionalised using semi-similar transformations and then solved numerically using an implicit finitedifference scheme known as the Keller-box method. Results pertaining to the flow and heat transfer characteristics are computed for all dimensionless time, uniformly valid in the whole spatial region without any numerical difficulties. Analytical solutions are also obtained for both small and large times, respectively representing the initial unsteady and final steady state flow and heat transfer. Numerical results indicate that the velocity ratio parameter is found to have a significant effect on skin friction and heat transfer rate at the surface. Furthermore, it is exposed that there is a smooth transition from the initial unsteady state flow (small time solution) to the final steady state (large time solution).

Keywords: Forced flow, Keller-box method, Stagnation point, Stretching flat sheet, Unsteady laminar boundary layer, Velocity ratio parameter.

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Authors: Wei Yee Teoh, Chee Wei Tan

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The issue of unintentional islanding in PV grid interconnection still remains as a challenge in grid-connected photovoltaic (PV) systems. This paper discusses the overview of popularly used anti-islanding detection methods, practically applied in PV grid-connected systems. Anti-islanding methods generally can be classified into four major groups, which include passive methods, active methods, hybrid methods and communication base methods. Active methods have been the preferred detection technique over the years due to very small non-detected zone (NDZ) in small scale distribution generation. Passive method is comparatively simpler than active method in terms of circuitry and operations. However, it suffers from large NDZ that significantly reduces its performance. Communication base methods inherit the advantages of active and passive methods with reduced drawbacks. Hybrid method which evolved from the combination of both active and passive methods has been proven to achieve accurate anti-islanding detection by many researchers. For each of the studied anti-islanding methods, the operation analysis is described while the advantages and disadvantages are compared and discussed. It is difficult to pinpoint a generic method for a specific application, because most of the methods discussed are governed by the nature of application and system dependent elements. This study concludes that the setup and operation cost is the vital factor for anti-islanding method selection in order to achieve minimal compromising between cost and system quality.

Keywords: Active method, hybrid method, islanding detection, passive method, photovoltaic (PV), utility method

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Authors: Seshi Reddy Kasu, Florian Misoc

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The use of hydroelectric pump-storage system at large scale, MW-size systems, is already widespread around the world. Designed for large scale applications, pump-storage station can be scaled-down for small, remote residential applications. Given the cost and complexity associated with installing a substation further than 100 miles from the main transmission lines, a remote, independent and self-sufficient system is by far the most feasible solution. This article is aiming at the design of wind and solar power generating system, by means of pumped-storage to replace the wind and /or solar power systems with a battery bank energy storage. Wind and solar pumped-storage power generating system can reduce the cost of power generation system, according to the user's electricity load and resource condition and also can ensure system reliability of power supply. Wind and solar pumped-storage power generation system is well suited for remote residential applications with intermittent wind and/or solar energy. This type of power systems, installed in these locations, could be a very good alternative, with economic benefits and positive social effects. The advantage of pumped storage power system, where wind power regulation is calculated, shows that a significant smoothing of the produced power is obtained, resulting in a power-on-demand system’s capability, concomitant to extra economic benefits.

Keywords: Battery bank, photo-voltaic, pump-storage, wind energy.

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Authors: Disciglio G., Nardella E., Gatta G., Giuliani M.M., Tarantino A.

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The bean (Phaseolus vulgaris L.) is one of the best known of the legumes, and it has a long cultivation tradition in Italy. The territory of “Subappennino Dauno” (southern Italy) is at around 700 m a.s.l. and is predominantly grown with cereals, olive trees and grapevines. Ecotypes of white beans to eat dry (such as cannellini beans) are also grown, which are sought for their palatability, high digestibility, and ease of cooking. However, these are not easy to find on the market due to their low production in relatively small areas and on small family farms that use seeds handed down from generation to generation. The introduction of these ecotypes in plain areas of the Puglia region would provide an opportunity to promote the diffusion of this type of bean. To investigate the adaptability of these ecotypes in plain environments (Cerignola, in southern Italy) a comparative trial was carried out between three ‘Monti Dauni’ ecotypes (E1, E2, E3) that are native to mountain areas and the similar commercial variety, ‘Cannellini’. The data provide useful information about the quantitative and qualitative characteristics of these ecotypes when grown in lowland environments. Ecotype E3 provided the greatest bean production (2.34 t ha-1) compared to ‘Cannellini’ (1.28 t ha-1) and the other ecotypes (0.55 and 0.40 t ha-1, for E1 and E2, respectively), due to its greater plant growth and the larger size of the seed (and thickness, in particular). Finally, ecotype E2 provided the greatest protein content (31.2%), although not significantly different from the commercial cultivar ‘Cannellini’ (32.1%).

Keywords: 'Monti Dauni' bean, ecotypes, adaptability in plain areas, quali-quantitive.

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Authors: W. Wen, G. Jackson, S. Maskill, D. G. McCartney, W. Sun

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CoNiCrAlY alloys have been widely used as bond coats for thermal barrier coating (TBC) systems because of low cost, improved control of composition, and the feasibility to tailor the coatings microstructures. Coatings are in general very thin structures, and therefore it is impossible to characterize the mechanical responses of the materials via conventional mechanical testing methods. Due to this reason, miniature specimen testing methods, such as the small punch test technique, have been developed. This paper presents some of the recent research in evaluating the mechanical properties of the CoNiCrAlY coatings at room and high temperatures, through the use of small punch testing and the developed miniature specimen tensile testing, applicable to a range of temperature, to investigate the elastic-plastic and creep behavior as well as ductile-brittle transition temperature (DBTT) behavior. An inverse procedure was developed to derive the mechanical properties from such tests for the coating materials. A two-layer specimen test method is also described. The key findings include: 1) the temperature-dependent coating properties can be accurately determined by the miniature tensile testing within a wide range of temperature; 2) consistent DBTTs can be identified by both the SPT and miniature tensile tests (~ 650 °C); and 3) the FE SPT modelling has shown good capability of simulating the early local cracking. In general, the temperature-dependent material behaviors of the CoNiCrAlY coating has been effectively characterized using miniature specimen testing and inverse method.

Keywords: CoNiCrAlY coatings, mechanical properties, DBTT, miniature specimen testing.

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Authors: Magdalena Escamilla Quintal, Thelma Cetina Canto, Cecilia Aguilar Ortega

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Due to the importance that people represent for companies, the setting of a clear control of the risks that threaten the health and the material and financial resources of workers is essential. It is irrelevant if the company is a small and medium-sized enterprise (SME) or a large multinational, or if it is in the construction or service sector. The risk prevention importance is related to a constitutional and human right that all people have; working in a risk-free environment to prevent accidents or illnesses that may influence their quality of life and the tranquility of their family. Therefore, the objective of this study was to determine the level of psychosocial risks (physical and emotional) of the employees of an SME. The participants of this study were 186 employees of a productive sector SME; 151 men and 35 women, all with an average age of 31.77 years. Their seniority inside the SME was between one month and 19.91 years. Ninety-six workers were from the production area, 28 from the management area, as well as 25 from the sales area and 40 from the supplies area. Ninety-three workers were found in Uman, 78 in Playa del Carmen, 11 in Cancun and seven in Cd. del Carmen. We found a statistically significant relationship between the burnout variable and the engagement and psychosomatic complaints as well as between the variables of sex, burnout and psychosomatic complaints. We can conclude that, for benefit of the SME, that there are low levels of burnout and psychosomatic complaints, the women experience major levels of burnout and the men show major levels of psychosomatic complaints. The findings, contributions, limitations and future proposals will be analyzed.

Keywords: Psychosocial risks, SME, burnout, engagement, psychosomatic complaints.

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Authors: David Calderón Villegas, Thomas Kalitzky

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Run-of-river (RoR) hydropower projects represent a viable, clean, and cost-effective alternative to dam-based plants and provide decentralized power production. However, RoR schemes’ cost-effectiveness depends on the proper selection of site and design flow, which is a challenging task because it requires multivariate analysis. In this respect, this study presents the development of an investment decision support tool for assessing the optimal size of an RoR scheme considering the technical, environmental, and cost constraints. The net present value (NPV) from a project perspective is used as an objective function for supporting the investment decision. The tool has been tested by applying it to an actual RoR project recently proposed in Colombia. The obtained results show that the optimum point in financial terms does not match the flow that maximizes energy generation from exploiting the river's available flow. For the case study, the flow that maximizes energy corresponds to a value of 5.1 m3/s. In comparison, an amount of 2.1 m3/s maximizes the investors NPV. Finally, a sensitivity analysis is performed to determine the NPV as a function of the debt rate changes and the electricity prices and the CapEx. Even for the worst-case scenario, the optimal size represents a positive business case with an NPV of 2.2 USD million and an internal rate of return (IRR) 1.5 times higher than the discount rate. 

Keywords: small hydropower, renewable energy, RoR schemes, optimal sizing, financial analysis

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Authors: O. Kratochvíl, J. Križan

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The paper deals with the analysis of the dynamic response of footbridges under human - induced dynamic loads. This is a frequently occurring and often dominant load for footbridges as it stems from the very purpose of a footbridge - to convey pedestrian. Due to the emergence of new materials and advanced engineering technology, slender footbridges are increasingly becoming popular to satisfy the modern transportation needs and the aesthetical requirements of the society. These structures however are always lively with low stiffness, low mass, low damping and low natural frequencies. As a consequence, they are prone to vibration induced by human activities and can suffer severe vibration serviceability problems, particularly in the lateral direction. Pedestrian bridges are designed according to first and second limit states, these are the criteria involved in response to static design load. However, it is necessary to assess the dynamic response of bridge design load on pedestrians and assess it impact on the comfort of the user movement. Usually the load is considered a person or a small group which can be assumed in perfect motion synchronization. Already one person or small group can excite significant vibration of the deck. In order to calculate the dynamic response to the movement of people, designer needs available and suitable computational model and criteria. For the calculation program ANSYS based on finite element method was used.

Keywords: Footbridge, dynamic analysis, vibration serviceability of footbridges, lateral vibration, stiffness, dynamic force, walking force, slender suspension footbridges, natural frequencies and vibration modes, rhythm jumping, normal walking.

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Authors: Takeshi Takeda

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An experiment utilizing the ROSA/LSTF (rig of safety assessment/large-scale test facility) simulated a 1.9% vessel upper head small-break loss-of-coolant accident with an accident management (AM) measure under the total failure of high-pressure injection system of emergency core cooling system in a pressurized water reactor. Steam generator (SG) secondary-side depressurization on the AM measure was started by fully opening relief valves in both SGs when the maximum core exit temperature rose to 623 K. A large increase took place in the cladding surface temperature of simulated fuel rods on account of a late and slow response of core exit thermocouples during core boil-off. The author analyzed the LSTF test by reference to the matrix of an integral effect test for the validation of a thermal-hydraulic system code. Problems remained in predicting the primary coolant distribution and the core exit temperature with the RELAP5/MOD3.3 code. The uncertainty analysis results of the RELAP5 code confirmed that the sample size with respect to the order statistics influences the value of peak cladding temperature with a 95% probability at a 95% confidence level, and the Spearman’s rank correlation coefficient.

Keywords: LSTF, LOCA, uncertainty analysis, RELAP5.

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Authors: Ivandic Kreso, Spiranec Miljenko, Kavur Boris, Strelec Stjepan

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This article discusses the possibility of using dilatometer tests (DMT) together with in situ seismic tests (MASW) in order to get the shape of G-g degradation curve in cohesive soils (clay, silty clay, silt, clayey silt and sandy silt). MASW test provides the small soil stiffness (G_o from v_s) at very small strains and DMT provides the stiffness of the soil at ‘work strains’ (M_DMT). At different test locations, dilatometer shear stiffness of the soil has been determined by the theory of elasticity. Dilatometer shear stiffness has been compared with the theoretical G-g degradation curve in order to determine the typical range of shear deformation for different types of cohesive soil. The analysis also includes factors that influence the shape of the degradation curve (G-g) and dilatometer modulus (M_DMT), such as the overconsolidation ratio (OCR), plasticity index (IP) and the vertical effective stress in the soil (s_vo'). Parametric study in this article defines the range of shear strain g_DMT and G_DMT/G_o relation depending on the classification of a cohesive soil (clay, silty clay, clayey silt, silt and sandy silt), function of density (loose, medium dense and dense) and the stiffness of the soil (soft, medium hard and hard). The article illustrates the potential of using MASW and DMT to obtain G-g degradation curve in cohesive soils.

Keywords: Dilatometer testing, MASW testing, shear wave, soil stiffness, stiffness reduction, shear strain.

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Authors: Deokho Kim, Wonwoo Lee, Jaewoong Lee, Teresa Ng, Gun-Ill Lee, Jiwon Jeong

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This paper presents a method for improving object search accuracy using a deep learning model. A major limitation to provide accurate similarity with deep learning is the requirement of huge amount of data for training pairwise similarity scores (metrics), which is impractical to collect. Thus, similarity scores are usually trained with a relatively small dataset, which comes from a different domain, causing limited accuracy on measuring similarity. For this reason, this paper proposes a deep learning model that can be trained with a significantly small amount of data, a clustered data which of each cluster contains a set of visually similar images. In order to measure similarity distance with the proposed method, visual features of two images are extracted from intermediate layers of a convolutional neural network with various pooling methods, and the network is trained with pairwise similarity scores which is defined zero for images in identical cluster. The proposed method outperforms the state-of-the-art object similarity scoring techniques on evaluation for finding exact items. The proposed method achieves 86.5% of accuracy compared to the accuracy of the state-of-the-art technique, which is 59.9%. That is, an exact item can be found among four retrieved images with an accuracy of 86.5%, and the rest can possibly be similar products more than the accuracy. Therefore, the proposed method can greatly reduce the amount of training data with an order of magnitude as well as providing a reliable similarity metric.

Keywords: Visual search, deep learning, convolutional neural network, machine learning.

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Authors: Yehjune Heo

Abstract:

Fingerprint Anti-Spoofing approaches have been actively developed and applied in real-world applications. One of the main problems for Fingerprint Anti-Spoofing is not robust to unseen samples, especially in real-world scenarios. A possible solution will be to generate artificial, but realistic fingerprint samples and use them for training in order to achieve good generalization. This paper contains experimental and comparative results with currently popular GAN based methods and uses realistic synthesis of fingerprints in training in order to increase the performance. Among various GAN models, the most popular StyleGAN is used for the experiments. The CNN models were first trained with the dataset that did not contain generated fake images and the accuracy along with the mean average error rate were recorded. Then, the fake generated images (fake images of live fingerprints and fake images of spoof fingerprints) were each combined with the original images (real images of live fingerprints and real images of spoof fingerprints), and various CNN models were trained. The best performances for each CNN model, trained with the dataset of generated fake images and each time the accuracy and the mean average error rate, were recorded. We observe that current GAN based approaches need significant improvements for the Anti-Spoofing performance, although the overall quality of the synthesized fingerprints seems to be reasonable. We include the analysis of this performance degradation, especially with a small number of samples. In addition, we suggest several approaches towards improved generalization with a small number of samples, by focusing on what GAN based approaches should learn and should not learn.

Keywords: Anti-spoofing, CNN, fingerprint recognition, GAN.

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Authors: A. Asem, N. Rastegar-Pouyani, P. De Los Rios, R. Manaffar, F. Mohebbi

Abstract:

Nowadays, biometrical characterizations of Artemia cysts are used as one of the most important factors in the study of Artemia populations and intraspecific particularity; meanwhile these characters can be used as economical indices. For example, typically high hatching efficiency is possible due to the small diameter of cysts (high number per gram); therefore small diameter of cysts show someway high quality of cysts. This study was performed during a ten year period, including two different ecological conditions: rainy and drought. It is important from two different aspects because it covers alteration of A. urmiana during ten years also its variation in the best and worst environmental situations in which salinity increased from 173.8 ppt in 1994 to 280.8 ppt in 2003/4. In this study the biometrical raw data of Artemia urmiana cysts at seven stations from the Urmia Lake in 1994 and their seven identical locations at 26 studied stations in 2003/4 were reanalyzed again and compared together. Biometrical comparison of untreated and decapsulated cysts in each of the seven similar stations showed a highly significant variation between 1994 and 2003/4. Based on this study, in whole stations the untreated and decapsulated cysts from 1994 were larger than cysts of 2003/4 without any exception. But there was no logical relationship between salinity and chorion thickness in the Urmia Lake. With regard to PCA analyses the stations of two different studied years certainly have been separated with factor 1 from each other. In conclusion, the interaction between genetic and environmental factors can determine and explain variation in the range of cysts diameter in Artemia.

Keywords: Artemia urmiana, Biometry, Cyst, Urmia Lake

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Authors: Saeid Fazli, Hajar Mohammadi D., Payman Moallem

Abstract:

This paper presents a robust method to detect obstacles in stereo images using shadow removal technique and color information. Stereo vision based obstacle detection is an algorithm that aims to detect and compute obstacle depth using stereo matching and disparity map. The proposed advanced method is divided into three phases, the first phase is detecting obstacles and removing shadows, the second one is matching and the last phase is depth computing. We propose a robust method for detecting obstacles in stereo images using a shadow removal technique based on color information in HIS space, at the first phase. In this paper we use Normalized Cross Correlation (NCC) function matching with a 5 × 5 window and prepare an empty matching table τ and start growing disparity components by drawing a seed s from S which is computed using canny edge detector, and adding it to τ. In this way we achieve higher performance than the previous works [2,17]. A fast stereo matching algorithm is proposed that visits only a small fraction of disparity space in order to find a semi-dense disparity map. It works by growing from a small set of correspondence seeds. The obstacle identified in phase one which appears in the disparity map of phase two enters to the third phase of depth computing. Finally, experimental results are presented to show the effectiveness of the proposed method.

Keywords: obstacle detection, stereo vision, shadowremoval, color, stereo matching

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Authors: Shilan Li, Ivan Arokiam, Peter Jarvis, Wendy Garner, Gazelleh Moradi, Stuart Wakefield

Abstract:

Development of a Robust Supply Chain for Dynamic Operating Environment as we move further into the twenty first century, organisations are under increasing pressure to deliver a high product variation at a reasonable cost without compromise in quality. In a number of cases this will take the form of a customised or high variety low volume manufacturing system that requires prudent management of resources, among a number of functions, to achieve competitive advantage. Purchasing and Supply Chain management is one of such function and due to the substantial interaction with external elements needs to be strategically managed. This requires a number of primary and supporting tools that will enable the appropriate decisions to be made rapidly. This capability is especially vital in a dynamic environment as it provides a pivotal role in increasing the profit margin of the product. The management of this function can be challenging by itself and even more for Small and Medium Enterprises (SMEs) due to the limited resources and expertise available at their disposal. This paper discusses the development of tools and concepts towards effectively managing the purchasing and supply chain function. The developed tools and concepts will provide a cost effective way of managing this function within SMEs. The paper further shows the use of these tools within Contechs, a manufacturer of luxury boat interiors, and the associated benefits achieved as a result of this implementation. Finally a generic framework towards use in such environments is presented.

Keywords: Lean, Supply Chain, High variety Low volume, Small and Medium Enterprises.

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Authors: Dionisios Panagiotaras, Elias Stathatos, Dimitrios Papoulis

Abstract:

 Sol-gel method has been used to fabricate nanocomposite films on glass substrates composed halloysite clay mineral and nanocrystalline TiO2. The methodology for the synthesis involves a simple chemistry method utilized nonionic surfactant molecule as pore directing agent along with the acetic acid-based solgel route with the absence of water molecules. The thermal treatment of composite films at 450oC ensures elimination of organic material and lead to the formation of TiO2 nanoparticles onto the surface of the halloysite nanotubes. Microscopy techniques and porosimetry methods used in order to delineate the structural characteristics of the materials. The nanocomposite films produced have no cracks and active anatase crystal phase with small crystallite size were deposited on halloysite nanotubes. The photocatalytic properties for the new materials were examined for the decomposition of the Basic Blue 41 azo dye in solution. These, nanotechnology based composite films show high efficiency for dye’s discoloration in spite of different halloysite quantities and small amount of halloysite/TiO2 catalyst immobilized onto glass substrates. Moreover, we examined the modification of the halloysite/TiO2 films with silver particles in order to improve the photocatalytic properties of the films. Indeed, the presence of silver nanoparticles enhances the discoloration rate of the Basic Blue 41 compared to the efficiencies obtained for unmodified films.

Keywords: Clay mineral, nanotubular Halloysite, Photocatalysis, Titanium Dioxide, Silver modification.

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Authors: Hassan Masoumi, Rashed Alavi

Abstract:

Wheat is one of the strategic crops in Iran, on which the household food basket is highly dependent. Although this crop is cultivated and produced in almost all provinces of the country, its production efficiency is lower than the global and regional averages due to the lack of optimal use of allocated resources. In this research, which was carried out with a documentary and library method, first, the total and partial productivity indices of irrigated wheat production were calculated in large, medium and small exploitation scales in different provinces of the country, and then the provinces were clustered in terms of these indices. The results showed that the total productivity of production factors had a direct correlation with the scale of exploitation, so that with the increase in the size of exploitations, the total productivity index increased. On the scale of small exploitations, North Khorasan, Zanjan, Chaharmahal and Bakhtiari Province, on a medium scale, Chaharmahal and Bakhtiari Province and on the scale of large exploitations, Zanjan, Chaharmahal and Bakhtiari provinces, Kohkiloyeh and Boyer Ahmad and North Khorasan, with better use of production resources compared to other provinces, were placed in the best cluster in terms of total productivity index. The high total productivity index in Zanjan, Chaharmahal and Bakhtiari Province is related to the higher productivity of factors such as mechanization and land in these provinces. Finally, the methods of using these factors in productive provinces, along with technical and specialized regional guidelines, can facilitate the improvement of productivity in less productive provinces.

Keywords: Clustering, Irrigated wheat, Iran, total productivity.

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Authors: E. Al-Essa, R. Bello-Mendoza, D. G. Wareham

Abstract:

Anaerobic batch experiments were conducted to investigate the effect of magnetite-supplementation (7 mM) on methane production from digested sludge undergoing two different microbial growth phases, namely fresh sludge (exponential growth phase) and degassed sludge (endogenous decay phase). Three different particle sizes were assessed: small (50 - 150 nm), medium (168 – 490 nm) and large (800 nm - 4.5 µm) particles. Results show that, in the case of the fresh sludge, magnetite significantly enhanced the methane production rate (up to 32%) and reduced the lag phase (by 15% - 41%) as compared to the control, regardless of the particle size used. However, the cumulative methane produced at the end of the incubation was comparable in all treatment and control bottles. In the case of the degassed sludge, only the medium-sized magnetite particles increased significantly the methane production rate (12% higher) as compared to the control. Small and large particles had little effect on the methane production rate but did result in an extended lag phase which led to significantly lower cumulative methane production at the end of the incubation period. These results suggest that magnetite produces a clear and positive effect on methane production only when an active and balanced microbial community is present in the anaerobic digester. It is concluded that, (i) the effect of magnetite particle size on increasing the methane production rate and reducing lag phase duration is strongly influenced by the initial metabolic state of the microbial consortium, and (ii) the particle size would positively affect the methane production if it is provided within the nanometer size range.

Keywords: Anaerobic digestion, iron oxide (Fe3O4), methanogenesis, nanoparticle.

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Authors: Shima Fasahat

Abstract:

This research is an experimental research which was done about microbial fuel cells in order to study them for electricity generating and wastewater treatment. These days, it is very important to find new, clean and sustainable ways for energy supplying. Because of this reason there are many researchers around the world who are studying about new and sustainable energies. There are different ways to produce these kind of energies like: solar cells, wind turbines, geothermal energy, fuel cells and many other ways. Fuel cells have different types one of these types is microbial fuel cell. In this research, an MFC was built in order to study how it can be used for electricity generating and wastewater treatment. The microbial fuel cell which was used in this research is a reactor that has two tanks with a catalyst solution. The chemical reaction in microbial fuel cells is a redox reaction. The microbial fuel cell in this research is a two chamber MFC. Anode chamber is an anaerobic one (ABR reactor) and the other chamber is a cathode chamber. Anode chamber consists of stabilized sludge which is the source of microorganisms that do redox reaction. The main microorganisms here are: Propionibacterium and Clostridium. The electrodes of anode chamber are graphite pages. Cathode chamber consists of graphite page electrodes and catalysts like: O₂, KMnO₄ and C₆N₆FeK₄. The membrane which separates the chambers is Nafion117. The reason of choosing this membrane is explained in the complete paper. The main goal of this research is to generate electricity and treating wastewater. It was found that when you use electron receptor compounds like: O_2, MnO₄, C₆N₆FeK₄ the velocity of electron receiving speeds up and in a less time more current will be achieved. It was found that the best compounds for this purpose are compounds which have iron in their chemical formula. It is also important to pay attention to the amount of nutrients which enters to bacteria chamber. By adding extra nutrients in some cases the result will be reverse.  By using ABR the amount of chemical oxidation demand reduces per day till it arrives to a stable amount.

Keywords: Anaerobic baffled reactor, bioenergy, electrode, energy efficient, microbial fuel cell, renewable chemicals, sustainable.

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