Browse

You are looking at 1 - 100 of 2,271 items

Abstract:

Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.

Restricted access
Authors: Kristóf Roland Horváth and István Kistelegdi

Abstract:

First Hungarian Active House refurbishment won the Active House Award and the Energy Globe Hungary prize in 2017. This paper provides insight into the renewal design process of the typical home from the 70’s under disadvantageous site conditions. Dynamic thermal simulations helped to gain insight into space organization and building envelope concepts and their effects on comfort and energy performance. The Active House Standard was applied to evaluate the calculation results. The most advantageous concept was selected for final design elaboration and construction. The implemented building proved that in the refurbishment process it is possible to achieve highest level of efficiency in operation energy consumption with positive yearly balance by simultaneously being able to rearrange the complete interior space and as a consequence the building shape and envelope into a competitive design at international level.

Open access

Abstract:

During sketch design stage for the new block of the University of Pécs, Medical School comfort and lighting simulations were applied to quantify optimization strategies. Simulation cases about shading possibilities, façade glazing ratios and internal heat storage masses evaluate the impact of illumination, solar gains, loads and heat transmission on visual and thermal comfort. The goal was to select the most favorable comfort, coupled with maximum reduction of investment costs. Concepts represent 14% (shading), 10% (reduced wall-window ratio), 11% (slabs without suspended ceilings), and 17% (combined wall-window ratio and thermal mass) improvement in thermal comfort performance, and it was proposed for further design.

Open access

Abstract:

The aim of the research is to make a comparison between system integrated measurement technologies in the field of engineering education in order to the students getting more detailed knowledge about the high level problem solving. A comparative case study was conducted with 3 different types of systems, as follows: Beckhoff, National Instruments, and HBM. The criteria of the systems are determined based on experience and the importance level of them was calculated by preference matrix. The ranks of the alternatives are calculated by Kesselring method, which provides the effectiveness value of the systems compared to the benchmark. The result of the paper shows a suitable method for selecting engineering systems.

Open access

Abstract:

In wireless sensors networks, data are sensed and recorded as databases, and then acceded by relational queries. Joins are queries that are largely used. Joins collect data from several nodes’ table. These are operations that typically consume a lot of energy because they generate a large number of messages in the network. Researchers worked to decrease this consumed energy. Many strategies were proposed in this way, but most of them addressed only binary joins. N-way joins received few interests. N-way joins perform join operations between more than two tables. They cause greater energy consumption. Additionally, the number of execution order is very important; it grows exponentially with the number of considered tables.

Restricted access

Abstract

Regional flood frequency analysis is considered to be an important and popular method for estimating different hydrological variables at ungauged sites. The estimation of the index flood is the essential problem when this method is applied. The objective of the study is a comparison of the estimation of the mean annual flood (or index flood) by using two approaches based on the ‘so-called’ index flood method and top-kriging. The concept behind these methods permits estimating the mean annual flood at ungauged locations using information taken from gauged sites located within the same homogeneous pooling groups. The study area comprises 104 gauging stations on the whole territory of Slovakia. The observation period of the annual maximum discharges of the selected stations was from 1961-2010. The identification of the homogeneous pooling group was performed using a non-hierarchical k-means clustering algorithm. The optimal number of clusters is determined by the Silhouette method. As a result, eight homogeneous pooling group clusters were identified. Finally, the results of the estimated mean annual floods using the index flood method and top-kriging were compared with the observed data. Top-kriging provided better results than the classical index flood method for estimating the mean annual flood at ungauged sites.

Restricted access

Abstract:

This paper presents a design procedure of a switched-mode power converter, the well-known synchronous buck converter: the calculating method, and how to choose the parts of the converter are presented in detail, like the inductor, the capacitor and the semiconductors as well as the design of the state feedback. During the design process the efficiency and the high switching frequency are very important: the switching semiconductors are Gallium Nitride based. Then, a linear-quadratic regulator is designed and applied to the particular case of a buck converter.

Open access

Abstract:

Numerous volume rendering techniques are available to display 3D datasets on desktop computers and virtual reality devices. Recently the spreading of mobile and standalone virtual reality headsets has brought the need for volume visualization on these platforms too. However, the volume rendering techniques that show good performance in desktop environment underachieve on these devices, due to the special hardware conditions and visualization requirements. To speed up the volumetric rendering to an accessible level a hybrid technique is introduced, a mix of the ray casting and 3D texture mapping methods. This technique increases 2-4 times the frame rate of displaying volumetric data on mobile and standalone virtual reality headsets as compared to the original methods. The new technique was created primarily to display medical images but it is not limited only to this type of volumetric data.

Open access

Abstract:

A building physics supported development was undertaken for the new block of the University of Pécs, Medical School. During sketch design stage climate, lighting and energy simulations were applied to quantify energy optimization strategies. Simulation cases assess the impact of shading technologies, wall-window ratios and thermal masses on used thermal energy demand. Based on a previous study about visual and comfort performance, goal was to identify the highest energy efficiency rates with maximum investment cost savings. Besides best comfort results, the most optimal development represents 9% saving in used thermal energy, and they were proposed for further design.

Open access

Abstract:

Development of thermal efficiency of the concentrated solar energy especially parabolic trough collector using various nanofluids types has a taken high interest in recent years. In this article enhancement thermal performance inside the heating collecting element of trough collector type LS-2 was simulated and improved using nanofluid consist of Tungsten Oxide WO3 inserting in Syltherm 800. Nanofluid effect was examined by solving the energy balance equation using MATLAB Software to cover wide range concentration volume 1-5% and inlet temperatures ranging from 350-650 K for the turbulent flow. The heat transfer performance and thermal efficiency were improved based on the results, and a notable increase was obtained when volume concentration had been increased compared with base fluid.

Open access
Authors: Shaymaa Alsamia, Mohammed Sh. Mahmood and Ali Akhtarpour

Abstract

The phenomenon of capillary rise happens in soils, and it has a crucial effect on many engineering applications. Many researchers have concluded several experimental equations to estimate this height. This paper presents a comparative and practical study of the three most important equations used in most researches, which are Lane and Washburn, Fetter, and P-K equations. The estimated heights by these three equations were compared with the experimental tests on sand samples taken from Al-Adalah, Al-Furat, and Al-Jameah districts located in Al-Najaf city in the southwest of Iraq. The percentage change for each equation compared with the experimental work. The results illustrated that the Fetter equation is the closest equation to experimental height and gives moderate values, unlike the Lane and Washburn and P-K equations, to save estimation of the pollutants penetration in unsaturated soils.

Restricted access

Abstract:

This paper describes the adaptation of the formex configuration processing to the computer program Grasshopper 3D and focuses on the applied mathematical solutions. Formex algebra is a mathematical system, primarily used for planning structural systems like truss-grid domes and vaults, together with the programming language Formian. The goal of the research is to allow architects to plan truss-grid structures easily with parametric design tools based on the versatile formex algebra mathematical system. To produce regular structures, coordinate system transformations are used. Owing to the abilities of the parametric design software, it is possible to apply further modifications on the structures and gain special forms. The paper covers the basic dome types, and it introduces additional dome-based structures using special coordinate-system solutions based on a spherical coordinate system, vault structures and their modifications based on a cylindrical coordinate system and circular structures and their modifications based on polar coordinates. Moreover two rotational grid tools are introduced, which uses coordinate system transformations on a unique way to create surfaces of revolutions based on the given generating curve and create grid structures on these surfaces. It also describes the solution technique to implement the triangular grid version of every one of these tools based on diamatic domes. The adaptation of formex algebra and the parametric workflow of Grasshopper together give the possibility of quick and easy design and optimization of special truss-grid domes.

Open access
Authors: Dávid Nagy, Tamás Mihálydeák and László Aszalós

Abstract:

Correlation clustering is a widely used technique in data mining. The clusters contain objects, which are typically similar to one another and different from objects from other groups. In the authors previous works the possible usage of correlation in rough set theory were investigated. In rough set theory, two objects are treated as indiscernible if all of their attribute values are the same. A base set contains those objects that are indiscernible from one another. The partition, gained from the correlation clustering, can be understood as the system of base sets, as the clusters contain the typically similar objects (not just to a distinguished member) and it considers the real similarity among the objects. In this work the extension of this study is presented, using the method to approximate graphs representing similarity relations.

Open access
Authors: László Pusztai, Balázs Kocsi, István Budai and Lajos Nagy

Abstract:

A key role of production managers at manufacturing companies is to make economy-based decisions related to production scheduling. If the production is subject to uncertain factors, like human resource or lack of standardization, production planning becomes difficult and calls for advanced models that are tailored to the manufacturing process. This research investigates a real furniture manufacturing system from both managerial and materialflow points of view. Statistical simulation was run on the manufacturing process, where the possible production structures were given. ANOVA analysis was calculated in order to identify those activities that have the most significant influence on the profit.

Open access

Abstract:

This paper deals with the dynamical analysis of a crane model. Truss finite elements are used to discretize the suspending chains with the so called updated Lagrangian description. This nonlinear model is regarded to be the best approximation to which linear models are compared. The inertia and independent degrees of freedom are also taken into consideration by linear models. The goal is to find a linear model, which can be used as an observer in antisway control of a crane.

Open access

Abstract:

Modeling and robotic handling of a plastic box buckle is discussed in this paper. The closing mechanism of the box buckle is simulated to determine the characteristic of the nonlinear load-deflection curve. An intelligent end-effector was designed and manufactured to handle the assembly with a robot. The closing force is measured by a built-in load cell and its values are processed by a micro-controller. The intelligent end-effector can be used in a robotic system, which deals with different snap-fit applications.

Open access

Abstract:

In 2013 Typhoon Haiyan, devastated several portions of the Philippines, which resulted in more than 7,000 deaths and thousands made homeless. The aim of this study is to propose a design of a permanent shelter as a continuation of the I-Siguro Daan Transitional Shelter, which was successfully deployed in 2014 and produce a transitional shelter prototype, for the victims of typhoon Haiyan. In order to develop the methodological design of the Permanent Shelter, the author presented several factors into consideration: the understanding how the rural communities use the present I-Siguro Daan Transitional Shelter; to further develop and improve the interior space of the shelter; to propose a better roof design; and to design a sustainable toilet and kitchen area for the users. Methodologies used in the study were the use of surveys and interactions with the community, which focuses on gaining the understanding how the communities use the present I-Siguro Daan Transitional Shelter. By exploring related case studies and literatures, site surveys and consultations with different groups, the resulting Permanent Shelter will a promising solution for improving the lives of the communities while also providing groundwork for future shelter related studies.

Restricted access

Abstract:

This paper proposes the application of energy efficient, low tech (passive) building design strategies and concepts in an industrial facility case study, in order to create a building with high efficiency and comfort within the boundaries of a tight investment cost. The planning process is supported by dynamic thermal and daylight simulations. Two versions were considered, a conventional industry building and a low tech one with climate zone based space organization. According to the evaluation of thermal and visual comfort as well as energy demand the selected version with the innovative passive concept delivered considerably better performance. According to the constructor’s concept, the reference building had to be placed by minimal adaptation on the new site. After considering and calling this concept into question, a new ‘energy design’ concept was elaborated at the sketch planning level. The new concept was compared with the reference building and a quantified, simulation assisted evaluation was provided about the cases. Since there was an essential improvement in comfort and energy level and, in addition, at architectural standard, the constructor could have been convinced to accept the new concept.

Open access

Abstract:

Day-lighting studies in buildings play a major role in indoor environmental investigation and can be conducted at the early stages of building design. Window position significantly affects day-lighting performance. This paper assessed the impacts of the window position on the visual comfort through two main factors; daylight factor and light uniformity in the hot and dry climate zone. In this study different window positions have been examined to achieve optimal visual comfort, using a dynamic simulation through Vi-suit plugin for Blender 3D software that controls the external application Radiance software. The results revealed that the window position at sill start from 1.4 m of a room characterized by (4.30 m × 3.00 m × 3.00 m) is the best compromising solution that complies with the daylight factor and light uniformity standards in the indoor environment. The findings of this study provide a more detailed and comprehensive analysis of the window design for architects/designers in the early building design stages in the hot and dry climate region.

Open access

Abstract:

Moment resisting frames are considered as an effective seismic force resisting system that is used for steel structures. Some of these structures that were built in high seismic hazard zones were designed according to old strength-based design codes. Currently, these structures do not meet the requirements of the new seismic codes. Therefore, the seismic retrofit of these structures is mandatory and cannot be overlooked. Steel braces and concrete-steel composite elements are common solutions for enhancing the seismic behavior of existing steel frame structures. This paper presents a numerical study that evaluates different possible techniques for the seismic retrofit of existing steel moment-resisting frame structures. The study investigates the performance of three multi-story buildings with different heights that are located in a high seismic hazard zone. Three retrofit techniques were introduced including; 1) X-Steel braces, 2) buckling restrained composite braces, and 3) composite concrete-steel plate shear walls. The seismic performance enhancement of the studied structures was evaluated in terms of the structure’s fundamental period, maximum inter-story drift and maximum base shear-to-weight ratios. Moreover, the cost of retrofitting material was estimated for each technique and they were compared to select the retrofit technique with the least constitutive material cost.

Open access

Abstract:

In this study the detailed One-at-a-Time sensitivity analysis of nonlinear mass spring-damper systems is carried out with numerical simulation. The degree of sensitivity was measured with a sensitivity index and based on its sensitivity Fuzzy-sets were established. The sensitivity of a parameter then can be expressed by the membership to the Fuzzy-sets. In this study the root mean square of acceleration, the maximum amplitude of acceleration and the peak frequency were chosen as output variables to measure sensitivity. With this research it was proven, that the root mean square of acceleration and the peak frequency can be used for sensitivity study of nonlinear vibration systems effectively.

Open access
Authors: Ahmed S. Al-Zuhairi, Alaa H. Altimimy, Ali T. Al-Aqbi and Hazim M. Al-Kargole

Abstract

Growing ramification in WSN contemplations are not restricted to routing, construction of protocols, dynamic of mobile nodes and infrastructure of the network. Although transcended to geometric level demonstrated as computational and dynamical geometries in spite of graph theory. In this paper we present step forward recognition features of a network devoted to solve the problem of reconstructing the disconnected network by connecting any disconnected chains. It considers geometrical properties of random depletion nodes deviated from unit grid. Number of chains and number of nodes in each chain are calculated with the average number of connections to a total nodes and longest chain. Histogram represented number of chains and numbers of nodes for each chain are used to show fragmentation of the network. Algorithm included a method to translate adjacent matrix to chain matrix and vice versa to check the agreement of initial case with the results. The amount of chain deviation and average connections per node for longest connected chain and for the total network are drawn as bar charts and conduct interpretations.

Open access

Abstract

The main cause of train derailment is related to transverse defects that arise in the railhead. These consist typically of opened or internal flaws that develop generally in a plane that is orthogonal to the rail direction. Most of the actual inspection techniques of rails relay on eddy currents, electromagnetic induction, and ultrasounds. Ultrasounds based testing is performed according to the excitation-echo procedure []. It is conducted conventionally by using a contact excitation probe that rolls on the railhead or by a contact-less system using a laser as excitation and air-coupled acoustic sensors for wave reception. The ratio of false predictions either positive or negative is yet too high due to the low accuracy of the actual devices. The inspection rate is also late; new numerical method has been developed in this context: The semi-analytical finite element method SAFE. This method has been applied in the case of anisotropic media [], composite plates [] and media in contact with fluids []. This method has been used successfully for several structures and especially in the case of beams of any cross-section such as rails that are the subject of this work and we were interested in wave propagation in waveguides of any arbitrary cross-section in the case of beams or rails.

Open access
Authors: Izz K. Abboud, Laith A. Kunbar and Abbas S. Hassan

Abstract

Direct sequence spread spectrum (DSSS) communication systems offer huge performance focal points in perspective on their low probability of block, improved performance in multipath fading situations and their capacity to stay away from interference by spreading the signal over a wide bandwidth subsequently conveying the power. For the transmitted sequence to be effectively received and demodulated, the spreading sequence utilized at the receiver ought to be like that utilized in the transmitter. This paper uses MATLAB Simulink to show a technique for synchronizing the code clock at the receiver with the code clock at the transmitter. This fine arrangement procedure is known as code tracking.

Open access

Abstract

Due to the extensive development of high-speed railway lines which are operating at increasing velocities, the dynamic performance of railway bridges has become an important issue of scientific research. The aim of this study is to investigate the possibility of reducing the vertical acceleration and displacement of pre-stressed reinforced concrete bridges beams by using passive nonlinear viscoelastic dampers to retrofit them. The proposed solution is based on connecting the dampers directly to the abutments and the bottom surface of the bridge deck with an eccentricity between the neutral axis of the bridge and the contact point of the viscoelastic dampers. First, the dampers are modeled through the concept of linearized fractional derivatives to obtain energetic equivalent linear viscoelastic dampers. Optimization of the configuration of these dampers was performed then as function of the orientation angle and the eccentricity. Considering two bridges having different length that were studied in the literature with other systems of damping, it was found that the best orientation angle of dampers is close to 60°. It was found also that, in order to satisfy Eurocode 1 requirements, the total equivalent damping coefficient for the actual damping system is less than half of that required for systems using auxiliary beam to fix dampers, which indicates higher efficiency of the proposed solution.

Open access

Cells and building structures. Part I.

Cells – point-like, line-like and surface-like bodies – building structures

Author: Géza Lámer

Abstract

The rooms of each building can be interpreted as three-dimensional cells. Borders (sides, edges) of rooms can be identified as the two-, one-, or zero-dimensional boundary cells of the three dimensional cell. The building structures identified as two-, one-, or zero-dimensional cells can be modeled by distinguished geometrical forms, surface-, line-, and point-like bodies. In accordance with the latter, building materials (finished products) can also be considered as surface-, line-, and point-like bodies.

The aim of the study is to create compliance between the cell elements and the building structures. It will be done at different levels:

  • – interpretation of relationship between building construction and cells,
  • – interpretation of relationship between building construction and selected bodies,
  • – interpretation the loadbearing's structure using cells,
  • – structure of the surface-construction and the cells,
  • – interpretation building types using cells.

In this paper (as part I) the first two items will be studied. The other three cases will be studied in another paper (as part II).

Open access

Abstract

The research team has developed a complex system that is capable to record and analyse various psychophysiological data. This article represents the program created in NI DIAdem which can automatically identify illnesses and generate reports based on the input and saved parameters. The created program can import data from different types of file formats. It is converted and saved in a new standardized format for further processing. It can play-back the processed data synchronized with adjustable speed, and visualize them on customized display areas. It can analyse the data based on the input parameters and the pre-defined mathematical equations. The program displays the input and calculated parameters, the results and the detected illnesses on automatically generated reports.

Open access
Authors: Munaf Fathi Badr, Ekhlas Hameed Karam and Noor Mohammaed Mjeed

Abstract

The objective of this paper is to present a proposed control model for the electromechanical damper mass spring system including the backstepping technique in comparison with the conventional proportional–derivative–integral (PID) controller unit to realize the best performance of the control systems. The suggested approach demanded the construction in laboratory arrangement of damper mass spring system which linked with electrical position sensor, and the theoretical work involved the derivation of the required mathematical equations in order to formulate the simulation models in Matlab software package. The obtained results show that the backstepping control technique provides the better performance associated with stable control system especially with increasing the value of selected mechanical load.

Open access

Abstract

In the recently published researches in the object localization field, 3D object localization takes the largest part of this research due to its importance in our daily life. 3D object localization has many applications such as collision avoidance, robotic guiding and vision and object surfaces topography modeling. This research study represents a novel localization algorithm and system design using a low-resolution 2D ultrasonic sensor array for 3D real-time object localization. A novel localization algorithm is developed and applied to the acquired data using the three sensors having the minimum calculated distances at each acquired sample, the algorithm was tested on objects at different locations in 3D space and validated with acceptable level of precision and accuracy. Polytope Faces Pursuit (PFP) algorithm was used for finding an approximate sparse solution to the object location from the measured three minimum distances. The proposed system successfully localizes the object at different positions with an error average of ±1.4 mm, ±1.8 mm, and ±3.7 mm in x-direction, y-direction, and z-direction, respectively, which are considered as low error rates.

Open access

Industry 4.0 from a few aspects, in particular in respect of the decision making of the management

/Will the new industrial revolution change the traditional management functions?/

Author: László Török

Abstract

The fourth industrial revolution, often identified as the terminology of Industry 4.0, more and more enforces changes and modifications from each participant of the socio-economic ecosystem. These enforced corrections concern the households, the governmental areas in different degrees, but the operation of the company sectors is rearranged most strongly by them. The study analyses this latter structure in the following respect: which are the most important supports of Industry 4.0 and what kind of competency elements are required from the employees and the management? According to the research data to be introduced, the domestic companies lag behind in preparations for the challenges raised by Industry 4.0; the international experiences are more favourable in this field. After—partial—review of the professional literature, the author concludes that the business sphere is in a condition before paradigm shift due to Industry 4.0. As per the analysis of decision-making based on digitalization, the question in the subtitle is answered—Industry 4.0 does not change fundamentally the traditional management functions of the company sector, but the decision-supporting applications based on digitalization must be learnt and applied. That statement seems to be founded that only company management, being able to live with decision making based on digitalization, can win competitive advantage.

Open access

Abstract

Today, the use of proportional-integral-derivative (PID) control units continues in many control applications due to their simple structure. In areas such as pressure, temperature, flow control, PID control element is used and many new methods are applied in adjusting control parameters. In this study, the LTR 701 Controlled Airflow and Temperature Experimental System was used to study the temperature and pressure control at different flow rates in the pipelines. In this control system, temperature was controlled with PID control element, pressure was controlled with PI control element, and reaction of control parameters at different temperatures and pressures were investigated. Also, temperature was controlled as cascade with PI element in elementary controller and P element in secondary controller. The manual adjustment method has been applied to adjust the control parameters. In addition, the experimental system is modelled in MATLAB-SIMULINK. On this model, simulation results showed that it is matching the experimental results.

Open access

Abstract

In this work a multilevel Computational Fluid Dynamics (CFD) analysis has been applied for the design of a Formula race car exhaust muffler with improved characteristics of sound pressure level (SPL) and fluid dynamic response. The approaches developed and applied for the optimization process range from the 1D to fully 3D CFD simulation, exploring hybrid approaches based on the integration of a 1D model with 3D tools. Modern mufflers typically have a complex system of chambers and flow paths. There are a variety of sound damping and absorbing mechanisms working to quiet the sound flowing through a muffler and piping system. Two calculation methods were selected for this study. The muffler has a complex inner structure containing perforated pipe and fiber material. Computer-aided design (CAD) file of the muffler was established for developing Finite Element Analysis (FEA) model in AVL BOOST v2017 and another commercial advanced design software (SolidWorks 2017). FEA model was made to monitor the flow properties, pressure and velocity. After the model was verified, sensitivity studies of design parameters were performed to optimize the SPL of the muffler. The software analysis results are included in the paper. Recommendations are made for obtaining smoother SPL curves for various measurement methods.

Open access

Abstract

In this work, a numerical method is proposed in order to achieve design optimisation of phased array (PA) probes for the special application of defects detection in thin films. This approach relies on an extended Fourier-based model that was adapted to predict the two-dimensional ultrasonic displacement field taking place in a thin plate under individual excitation of PA probe elements which have arbitrary orientation with respect to the examined part surface. Excitation is applied through a fluid couplant and is operated at scheduled delays that are managed to enable emission of constructive pulses. This gives the possibility to steer sound waves towards a direction and to focalize the beam in a selected point. An optimisation algorithm based on the concept of pattern search that does not require evaluation of a gradient was used to find the best match in the multidimensional analysis space of possibilities including the elements orientation angles, the elements lengths, the inter-elements distances and work frequency. Optimisation was performed with the objective to maximize the displacement amplitude at the focal point while minimizing simultaneously the effect of beam side lobes. The results obtained by this approach reveal that focalisation can be achieved with enhanced features in comparison with previous algorithms assuming linear elements that are parallel to the surface of the plate.

Open access
Authors: Norbert Novák, Péter Miklós Kőmíves, Mónika Harangi-Rákos and Károly Pető

Abstract

The role of rural areas partly changed in the last decades. The countryside is still functioning as the main food producer of the world and this role became much more important because of the global population growth and because of the change in dietary habits. But other rural functions appeared just like recreation, health preservation, and on the other hand the different ecological functions' importance increased. The population living in the countryside is continuously decreasing as more and more people try to move into urban areas. One of the main aims of this article is to give a brief literature overview on the services needed in the rural areas in order to stop migration from the countryside to the cities. Based on extensive literature review the article summarizes the changing functions of the countryside and tries to list those developments which are needed to preserve rural population.

Open access

Abstract

In the building mechatronics research centre of University of Debrecen, Faculty of Engineering, a new laboratory has been designed, named “Cyber-physical and intelligent robot systems laboratory”. The possibility to design and test unique and platform-independent systems was among the main goals, hoping that the system itself and its advancements may later be used in manufacturing industries as well.

Fulfilling the needs of “Industry 4.0” is a challenging task, as it requires every single device (e.g. industrial robots) to be connected to the same network, where they may be monitored and controlled. However, there are some factors that limit this, such as the periodical “instability” that some machines have, caused by singularity points.

The following material studies these so-called singularities of a KUKA KR5 industrial welder robot placed in a robot cell, from an engineering viewpoint.

Open access

This study was conducted to assess the effects of 2,4-epibrassionolide (EBR) on mold decay caused by Rhizopus stolonifer and its capability to activate biochemical defense reactions in postharvest peaches. The treatment of EBR at 5 μM possessed the optimum effectiveness on inhibiting the Rhizopus rot in peach fruit among all treatments. The EBR treatment significantly up-regulated the expression levels of a set of defense-related enzymes and PR genes that included PpCHI, PpGns1, PpPAL, PpNPR1, PpPR1 and PpPR4 as well as led to an enhancement for biosynthesis of phenolics and lignins in peaches during the incubation at 20 °C. Interestingly, the EBR-treated peaches exhibited more striking expressions of PR genes and accumulation of antifungal compounds upon inoculation with the pathogen, indicating a priming defense could be activated by EBR. On the other hand, 5 μM EBR exhibited direct toxicity on fungal proliferation of R. stolonifer in vitro. Thus, we concluded that 5 μM EBR inhibited the Rhizopus rot in peach fruit probably by a direct inhibitory effect on pathogen growth and an indirect induction of a priming resistance. These findings provided a potential alternative for control of fungal infection in peaches during the postharvest storage.

Restricted access

Microalgae are promising alternatives to sequestration of carbon and reduction of environmental problems, e.g. the greenhouse effect and industrial water pollution. Depending on the growth conditions, microalgae can differ in their metabolism products, leading them to grow at different rates. Intracellular reactions and nutritional requirements from cell metabolism, as well as biomass composition, may vary in function of the temperature. In this study, the biotechnological potential of three microalgae strains from the species was evaluated in terms of growth, biomass composition, fatty acid profile, and chlorophyll and carotenoids contents. Each of the three species demonstrated different potential depending on their metabolisms: Scenedesmus spinosus presented fastest growth and had the highest protein content (52.99%), Pseudokirchneriella subcapitata presented the highest content of lipid extracted (26.51%), and Scenedesmus acuminatus showed increased production of chlorophyll (5.25 mg l–1) and carotenoid (1.02 mg l–1) pigments.

Restricted access

Consumer concern over artificial food additives has stimulated production of pigments from natural sources. The aim of this study was to examine the effects of process variables on the content of colour compounds (betaxanthin and betacyanin) in beetroot peel juice extracted by conventional method. In this research, the extraction processes were carried out according to the central composite design with different process variables. Quantitative measurements of the basic colour compounds in beetroot extract were performed using spectrophotometer. From our experiment, it was found that the most adequate extraction conditions, which gave the highest yield of colour compounds (952.5 mg l–1 of betaxanthin and 1361 mg l–1 of betacyanin), were extraction time 1 h, operating temperature 20 ºC, and solvent ratio 0.8 w/v. Being a conventional heating method, it is a simple and cost efficient process with relatively high yield.

Open access

Tomatoes (Solanum lycopersicon L.) are one of the most important and most widely consumed vegetables in the world. The fruit contains considerable amount of different phytonutrients such as carotenoids, tocopherols, and vitamin C. In the present work, effects of some abiotic factors on the concentration of phytonutrients were investigated in tomato cultivated in two different types of soil. It was found that the type of soil had slight effect on the most important vital nutrients, while the ecological factors, particularly precipitation and average temperature 3 weeks before harvest, were of significant influence on such nutrients. It was found that low temperature and high precipitation before harvest caused the levels of carotenoids, tocopherol, and vitamin C to significantly increase by 65%, 46%, and 28%, respectively.

Open access

Barberry is a native Iranian plant including species Berberis integerrima and B. vulgaris. Barberry fruit is used for preparing sauces, jellies, carbonated drinks, candies, food colour powders, jams, marmalades, chocolates, juices, and nectars. They are used as a natural food colorant rich in anthocyanins instead of harmful artificial ones. They contain polyphenols and antioxidants that reduce damage from free radicals and prevent chronic diseases and cancers. Barberry fruit extracts were encapsulated in maltodextrin by spray drying and Liposome Entrapment. The sizes of spray dried particles were reported 1–20 μm by SEM. Dimensions of empty and extract loaded liposomes (B. vulgaris and B. integerrima) were 18–28, 37–51, and 51–77 nm, respectively, by FE-SEM. The moist diameter of liposomes measured by dynamic light scattering (DLS) method at day 0 and after 6 months at –18 °C were as follows; empty liposomes: 163.9±2.23 and 378.90±4.98, liposomes loaded with extracts: 135.2±2.04 and 160.90±2.19 (B. vulgaris) and 113.4±1.83 and 144.20±2.01 nm (B. integerrima). Evaluation of thermal-oxidative decomposition from Differential scanning calorimetry (DSC) results at 0–45–90 days showed that the antioxidant activity and the onset temperature of the encapsulated extract was higher than the control. The extracts encapsulated in liposomes, especially B. integerrima extract, had better antioxidant properties.

Restricted access

There is a great demand for developing efficient anthocyanins extraction related to each plant material. Conventional methods have been replaced by novel techniques, but they might remain attractive when combined with the latter. Anthocyanins extraction from fresh and dried red cabbage was investigated by maceration, ultrasonication, and with enzymes. Pre-treatments through drying determined an improved extraction with respect to fresh samples, freeze-drying emerging as the best method. Combined enzyme-assisted extraction with maceration resulted in higher yield by conducting several extractions (1078.8±12.5 mg/100 g DW). The kinetic studies revealed good stability of anthocyanins at 50 °C, while constant degradation at 80 °C. The rate constant k at 80 °C and pH 3.5 was 1.7 10–3 min–1 and the half-life time t 1/2 was 6.7 h. Thermal analysis evidenced heat-induced changes in particular for extracts undergoing pre-heating. These results are valuable for optimal processing conditions of anthocyanins-containing products.

Restricted access

Xylanase plays an important role in the food, feed, and pulp/paper industry. Filamentous fungi have been considered as useful producers of this enzyme from an industrial point of view, due to the fact that they excrete xylanases into the medium. In this study, four fungal species belonging to different genera, i.e. Aspergillus, Cochliobolus, Pyrenophora, and Penicillium were isolated from different sources and compared for their ability to produce xylanase in submerged culture. The fungal species showed enzyme activity as determined by dinitrosalicylic acid (DNS) method. It was found that the two saprophytic Aspergillus strains, i.e A. terreus (Fss 129) and A. niger (SS7) had the highest xylanase activity of 474 and 294 U ml–1 at pH 7 and 8, respectively, in the presence of corn cob hulls after 120 h of incubation. The production of xylanase seemed to be strongly influenced by the interactive effect of initial pH on the fungi. Interestingly, xylanase was better produced by the saprophytic fungi of Aspergillus and Penicillium than by the plant pathogenic ones of Cochliobolus and Pyrenophora. This work provides additional information to support future research on fungi with different lifestyles for food industrial production of xylanase.

Restricted access

Changes of edible oil quality factors and formation of 3-monochloro-1,2-propanediol fatty acid esters (3-MCPD-FE) during deep-fat frying in four different experiments (control, salt, pork chop, and chicken liver) with high oleic sunflower oil were compared in this study. Based on the results of investigated oil quality parameters, which were free fatty acid (FFA), anisidine value (AV), UV extinction at 232 and 268 nm (E232 and E268, respectively), and total polar material (TPM), only a modest deterioration of the frying oil was observed. As we expected, the 3-MCPD-FE content in the control samples did not reach the limit of quantification (0.1 mg kg–1), while the table salt itself caused a slight increase. The results of pork chop and chicken liver experiments were not statistically different from each other, after the third frying circle 0.52 and 0.39 mg kg–1 3-MCPD-FE levels were reached, respectively. Based on these values, the human exposure estimation resulted in a low risk.

Open access

The breadmaking quality of bug-damaged wheat flours with high protease activity (HPAWF) and low protease activity (LPAWF) was attempted to be improved by using sourdough (prepared by L. plantarum (SD1) and L. sanfrancissensis (SD2)) and liquid rye sour (LRS) in this study. The effects of sourdoughs (20 and 40%) and LRS (1 and 2%) on the protease activity of the HPAWF were determined by SDS-PAGE. Protease activity of HPAWF decreased with the addition of 40% SD1, 20% SD2, and both levels of LRS (1 and 2%) compared to a control sample. The HPAWF bread samples produced with LRS (1 and 2%) had higher volume (P<0.05) and bread quality as compared to sourdough applications. LPAWF bread sample was comparable with those of 40% SD2 added sample in terms of volume and hardness (N) values (P>0.05), while SD1 addition caused quality losses. The overall results suggested that addition of 2% LRS had promising results for improving bread quality flours that were damaged by suni-bug at low levels.

Restricted access
Authors: R. Amiri Qandashtant, E. Ataye Salehi, A. Mohamadi Sani, M. Mehraban Sangatash and O. Safari

Probiotic food products are available at the supermarket commercially, but probiotic bakery products are much less in evidence. In the present study, methyl cellulose (2%), whey protein concentrate (2%), corn starch (1%), and soybean oil at 2, 4, and 6% were used for coating layer on the bulked bread surface, and then the quality properties were studied. The results showed that Lactobacillus rhamnosus GG, as probiotic component of the coating, immobilized in corn starch, whey protein, and methyl cellulose films had enhanced viability throughout shelf-life. The probiotics remained viable for 4 days, maintaining high viable cell number levels. Adding soybean oil at 6% concentration enhanced texture, sensory properties, and image index during storage.

Restricted access
Authors: E. Horvath-Szanics, J. Perjéssy, A. Klupács, K. Takács, A. Nagy, E. Koppány-Szabó, F. Hegyi, E. Németh-Szerdahelyi, M.Y. Du, Z.R. Wang, J.Q. Kan and Zs. Zalán

The increasing consumer demand for less processed and more natural food products – while improving those products’ quality, safety, and shelf-life – has raised the necessity of chemical preservative replacement. Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Chitinolytic enzymes are of biotechnological interest, since their substrate, chitin, is a major structural component of the cell wall of fungi, which are the main cause of the spoilage of food and raw plant material. Among the several organisms, many bacteria produce chitinolytic enzymes, however, this behaviour is not general. The chitinase activity of the lactic acid bacteria is scarcely known and studied.

The aim of the present study was to select Lactobacillus strains that have genes encoding chitinase, furthermore, to detect expressed enzymes and to characterise their chitinase activity. Taking into consideration the importance of chitin-bindig proteins (CBPs) in the chitinase activity, CBPs were also examined. Five Lactobacillus strains out of 43 strains from 12 different species were selected by their chitinase coding gene. The presence of the chitinase and chitin-biding protein production were confirmed, however, no chitinolytic activity has been identified.

Open access

Immature rice grain is one of the under-valued by-products of rice milling industry. In this study, it was aimed to investigate the effects of immature rice grain flour (IRGF) substitution to tarhana, which is a traditional cereal-based, fermented food product. IRGF was replaced by refined wheat flour at the levels of 0 (control), 30, 50, 70, and 100%, and the effect of this replacement on the contents of crude fat, ash, protein, dietary fibre, phytic acid, minerals, vitamins B1 and B2, tocopherols, γ-oryzanol contents and sensory properties were investigated. It was shown that stabilised IRGF remarkably improved nutritional properties of the end product without adversely affecting sensory quality up to 50%. In conclusion, it could be suggested that stabilised IRGF has a promising potential for many food applications due to being cheap, accessible, nutritious, and gluten-free.

Open access

Abstract

The sol gel method was used in preparing a series of A site partially substituted La1−xBaxCoO3 (x ≥ 0.1 ≤ 0.4) perovskite catalysts coded LBC1, 2, 3, and 4 and their potential as catalysts for soot oxidation were evaluated. The Brunauer–Emmett–Teller (BET), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES), Thermogravimetric/Differential Thermal Analysis (TGA/DTG), X-ray analysis (XRD) were used in characterizing the prepared perovskite catalyst. The result shows that at (x≥ 0.2 ≤ 0.4), there was an increase in surface area when we compare it with that of x = 0. The increase in surface area helps in increasing the catalytic performance of the catalyst. Also, when evaluating the catalytic performance of the synthesized catalysts, it was observed that doping the perovskite catalysts helped in the general improvement of the catalytic performance for soot oxidation. The best performance in this research study with a T50 of 484 °C was observed at x = 0.2 catalyst (LBC2). This shows that the non-noble perovskite catalysts prepared in this research study has the potential to replace the noble metal based catalysts used presently in the diesel automotive industry.

Open access
Authors: G. Lizia Thankam and Neelakantan Thurvas Renganathan

Abstract

Though being an ancient trend, usage of the homogeneous material cement in the construction industry is steadily getting eradicated with the springing up of supplementary cementing materials (SCM). Metakaolin is an imminent mineral admixture extracted from the mineral ore kaolinite, which enhances the interfacial zone by more efficient packing at the cement paste-aggregate particle interface, thus reducing the bleeding and producing a denser, more homogeneous transition zone microstructure. This paper depicts the various repercussions of the pozzolanic material metakaolin in the fresh and hardened properties of concrete when replaced with cement in finite amount. Also, it states the behavior of high-performance concrete and self-compacting concrete with metakaolin.

Open access

Abstract

The inelastic buckling behaviour of different rectangular thin isotropic plates having a free edge is studied. Various combinations of boundary conditions are subject to in-plane uniaxial compression and each rectangular plate is bounded by an unloaded free edge. The characteristic deflection function of each plate is formulated using a polynomial function in form of Taylor–Maclaurin series. A deformation plasticity approach is adopted and the buckling load equation is modified using a work principle technique. Buckling coefficients of the plates are calculated for various aspect ratios and moduli ratios. Findings obtained from the investigation are found to reasonably agree with data published in the literature.

Open access

Abstract

Industry 4.0 is referred as the fourth industrial revolution that represents the information intensive transformation of industrial automation and manufacturing processes. Cyber-physical systems (CPS) are building blocks in Industry 4.0 and part of the Industry 4.0 vision. This paper presents a cyber-physical platform development and implementation strategy for Industry 4.0 applications. It has been considered a cyber-physical platform model (CPP) built upon hardware reconfigurable technology based on a Field Programmable Gate Array (FPGA) processor framework. The development strategy exploits the full benefits enabled by reconfigurable hardware, such as scalability of complex systems, platform-based design approach, adaptive processing, real-time constrains management, or high performance prototyping capabilities. The implemented experimental setup also combines major advantages of both the hardware and software platform-based design trends in Industry 4.0. In this endeavor, the used software toolkit comprises the entire system complexity as a high performance integration layer. The presented design method and implementation strategy can serve as rough orientation for future CPS research and development activities.

Open access

Abstract

Reliability is one of the most important criteria that characterize last generation digital systems. In a wide range of applications the required reliability level is achieved by using hardware redundant configurations. Perhaps their most common form is the triple modular redundancy (TMR) based on a majority voting structure. Researchers that use this strategy make a major assumption: in fault-free operation mode the outputs of these digital systems match in all. This paper proves that synchronization and matching in all the outputs of such systems is not such a trivial problem. In this endeavor FPGA-based (Field Programmable Gate Arrays) redundant topologies are considered for study and experiments. Upon these structures specially conceived redundant models have been developed and simulated. The results outline that synchronization of complex digital systems is a difficult engineering undertaking and any initial assumption should be managed with the adequate circumspection.

Open access

Abstract

Information management and sharing is an essential ingredient, but a difficult and challenging problem for disaster response management. This paper proposes an ontology as a model to organize and structure information in order to improve the information management and sharing in disaster response management. The ontology was designed and developed based on philosophically grounded foundational ontologies. It was also implemented in ontological languages and demonstrated and evaluated in a case study of the flood evacuation process. This paper also provides a systematic approach to develop a well-founded domain ontology that addresses both static and dynamic aspects of a given domain.

Open access

Abstract

The objective of this work is to investigate the rotary friction welding of AA1100 aluminum alloy with mild steel, and to optimize the welding parameters of these dissimilar materials, such as friction pressure/time, forging pressure/time and rotational speed. The optimization of the welding parameters was deduced by applying Response Surface Methodology (RSM). An empirical relationship was also applied to predict the welding parameters. Tensile test and micro-hardness measurements were used to determine the mechanical properties of the welded joints. Some joints were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) in order to investigate the formation of intermetallic compound (IMC) layer at the weld interface. Experimentally, the tensile strength of the weld increases with increasing the forging pressure/time, while the low level of forging pressure/time allows the formation of an IMC layer which reduces the tensile strength of the weld.

Open access

Abstract

The use of energy in the world today is increasing with increase in population. The cost and availability of energy significantly impacts our quality of life, the health of national economies and the stability of our environment. The rapid depletion of fossil fuel resources on a worldwide basis has necessitated an urgent search for alternative energy sources to cater to the present day demands. In recent years there has been a significant global commitment to develop clean and alternative sources of energy such as solar and wind. Wind energy technology has been the fastest growing energy source because it is fairly distributed around the world and readily available for use. However, more penetration of wind energy into existing power networks has some impacts on the stability of the power system. Therefore, this paper studies and analyzes the stability of a power system with increasing wind penetration. The paper presents some analyses of a power system and the dynamic behavior which identify the issues that limit the large-scale integration of wind generators in a power system.

Open access

Abstract

Frequency Hopping Spread Spectrum (FHSS) communications utilizes a pseudo random code to spread the bandwidth of the data being transmitted over a much wider range than is required by the data. Due to the pseudo random nature of the carriers selected for transmission, the spreading and dispreading process must occur simultaneously to recover the transmitted data signal. This requires the receiver have knowledge about the instant the transmitter began transmitting and the propagation delay between the two. However, in real world systems, this information is unavailable to the receiver. The paper utilizes MATLAB Simulink to demonstrate a method of synchronizing the code clock at the receiver with the code clock at the transmitter. This fine alignment process is known as code tracking.

Open access

Abstract

Natural rubber (NR) vulcanizates were prepared from natural rubber and chitin using a two-roll mill. The chitin was extracted from crab shell waste obtained from a local market in Oron, Akwa Ibom State, Nigeria using the chemical extraction method. The effects of the chitin at different contents (0–40 phr) on the mechanical properties of the NR/Chitin vulcanizates with carbon black as reference filler have been investigated. The tensile strength of the chitin filled natural rubber (NCH), and the carbon black filled natural rubber (NCB) vulcanizates were found to increase with an increase in filler content to reach optimum at 30 phr after which it decreased. The hardness, impact and abrasion resistance properties of the NCH and NCB vulcanizates increased as filler content increases. The tensile strength and abrasion resistance of the vulcanizates containing blends of varying percentages of carbon black to chitin (CBCH) increased as more carbon black (CB) is introduced while the hardness and impact strength increased with increase in chitin content. However, carbon black filled vulcanizates showed better property enhancement than the chitin filler.

Open access

Abstract

The Szentgyörgyi-Horváth-house is one of the major historical buildings of Balatonfüred. The design of the reconstruction was preceded by detailed architectural historical study. The reconstruction of the building was realized by retaining the original structures. For the new function the building was equipped with an air-conditioning engine-room. The air conditioner is a significant source of noise for the apartments facing the courtyard of the building, due to its continuous operation. The acoustic examination of the enclosed yard was calculated with two different approaches. The distance-dependent approximation, which is usual for large halls, was approved. Building construction structures were determined based on the results to meet the acoustic requirements.

Open access