International Journal of Engineering
Year:2017 | Volume:30 | Issue:4 (TRANSACTIONS A: Basics)|Papers Count:20

Chitosan was used for nanoencapsulation of Lactobacillus acidophilus as probiotic bacteria. In vitro experiments were conducted with the objective of investigating the survival of the bacterial cells in gastro-intestinal conditions. The results demonstrated that the size of chitosan nanoparticles noticeably increased by increasing chitosan concentration from 0. 05 to 0. 5 g/mL. Encapsulation of the cells caused a decrease at the leakage of probiotic bacteria when compared to free bacteria. However, the number of probiotic cells reduced from 3. 27 to 3. 23 log CFU/mL in gestural acid condition in contrast to free cells which they approximately dropped from 3. 3 to 3 log CFU/mL after 120 min. Good probiotic viability and stability was also obtained by nanocapsulation of Lactobacillus acidophilus in intestinal juice. At this condition, the initial capsulated cells numbers were 3. 28 log CFU/mL which after placing in biliary salt condition for 120 min, it reached to 3. 23 log CFU/mL. On the other hand, the free bacteria cells reduced from 3. 3 to 2. 97 log CFU/mL in intestinal environment. Overall, nanocapsulation of probiotic bacteria plays a pivotal role in enhancing the viability and survival of them against gastro-intestinal environmental conditions.

A two fluid model (TFM) was used to study gas-solid heat transfer in a riser with different inclination angles. A two dimensional pipe with 5. 8 cm internal diameter and 5 meter length was chosen. Effect of bed angle and solid particles feed rate were studied on the heat transfer behavior of gas and solid particles. Obtained results from simulation are compared with the experimental data in the relevant literature. Heat transfer behavior of phases is different in an inclined pipe in comparison with vertical and horizontal pipes. It is found that higher air-solid Nusselt number, air temperature difference and particle temperature difference take place at the pipe with inclination angle equal to 45 degrees. Loading ratio enhancement increases gas temperature differences. At lower and higher loading ratio, particles temperature differences decreases and increases respectively with loading ratio enhancement.

Today concrete is most generally utilized development material in the world due to its strength and sturdiness properties. To attain good strength, curing of concrete is important so we introduce the concept of self-curing concrete rather than immersion or sprinkle curing to avoid water scarcity. It was observed that water solvent polymers can be utilized as a self-curing agent, i. e. polyethylene glycol (PEG-400). In the present study, to discover the effect of admixture polyethylene glycol (PEG-400) on compression strength, split tensile strength and flexural strength, adding the diverse rate of PEG-400 to the weight of cement from zero to two percentages as the measurement of the curing agent is done. The test results were studied for M30 concrete mix. The optimum percentage of PEG-400 was found to be 1% for compressive and Split Tensile Strength. If the dosage of PEG-400 increases to more than 1%, there is a decline in compressive and split tensile strength. However, the optimum percentage of PEG-400 for flexural strength was found at 0. 5%. If we increase the dosage of PEG-400 more than 0. 5%, there is reduction in strength of flexural strength.

Failure of dams due to overtopping is among the most frequent forms of embankment failures. Owing to massive and wide spread damage to structures and loss of lives associated with a dam failure, the subject has drawn the attention of scientists. The study also becomes essential for damage assessment and for development of early warning system of people downstream of the embankment. The rate of breaching of earthen embankments due to overtopping depends upon the soil and flow characteristics alike. Different input parameters that help in understanding the phenomenon are the temporal variation of initiation of the breach, breach width, breach depth, intensity of discharge and its time-to-peak. Present paper gives the results of laboratory investigation conducted using a wooden fuse plug and five different soils. The hydraulic conditions were kept same for all the experiments. It was observed that cohesiveness and degree of compaction were key factors in the erosion process. While for pure noncohesive soils, surface erosion occurred gradually, but for the cohesive soils, headcut erosion was observed. The behaviour of breach depends upon dimensions of fuse plug, type of fill material, reservoir capacity and inflow. A common equation has been fitted to the series of normalized breach flow hydrographs of different soils. The equation has a coefficient of correlation R2 equal to 0. 8 indicating a good fit. Limited space of storage reservoir on the upstream of the embankment, and width of the flume are the limitations of the study.

Detecting communities plays a vital role in studying group level patterns of a social network and it can be helpful in developing several recommendation systems such as movie recommendation, book recommendation, friend recommendation and so on. Most of the community detection algorithms can detect disjoint communities only, but in the real time scenario, a node can be a member of more than one community at the same time, that leads to overlapping communities. A novel approach is proposed to detect such overlapping communities by extending the definition of newman’ s modularity for overlapping communities. The proposed algorithm is tested on LFR benchmark networks with overlapping communities and on real-world networks. The performance of the algorithm is evaluated using popular metrics such as ONMI, Omega Index, F-score and Overlap modularity and the results are compared with its competent algorithms. It is observed that extended modularity gain can detect highly modular structures in complex networks with overlapping communities.

These days, the most important areas of research in many different applications, with different tools, are focused on how to get awareness. One of the serious applications is the awareness of the behavior and activities of patients. The importance is due to the need of ubiquitous medical care for individuals. That the doctor knows the patient's physical condition, sometimes is very important. Of course, there are other important applications for this information. There are a variety of methods and tools for measurement, gathering, and analysis of the physical behaviors and activities’ information. One of the most successful tools for this aim are ubiquitous intelligent electronic devices, specifically smartphones, and smart watches. There are many sensors in these devices, some of which can be used to understand the activities of daily living. As an output result, these sensors produce many raw data. Thus, it is needed to process these information and recognize the individual behavior of the output of this processing. In this paper, the basic components of the analysis phase for this process have been proposed. Simulations validate the benefits and superiority of this method.

In this paper the method of sensorless startup of direct current brushless motor using third harmonic back Electromotive Force (EMF) and motor startup using microcontroller for pulse width modulation, power switch control and motor output analysis is presented which renders RPM control and high speed achievement for motor. The microcontroller is used for processor and metal-oxide semiconductor field-effect transistor (MOSFETs) are used for power circuit. Besides, the motor does not have any sensors to detect rotor position. Furthermore, the microcontroller modulates pulse width, controls power circuit and analyses motor output. The innovation in this research is that the third harmonic function is used for motor control and is compared with the Back-EMF force to recognize zero crossing. Moreover, N-type MOSFETs are used in power circuit high side and low side which are useful in the current rate of MOSFETs due to their similarities. Also, the IR2101 MOSFET drive is utilized for startup which improves the firing time of MOSFETs. Besides, using tantalum capacitors and putting resistor by the gate route of MOSFETs is efficient. Finally, experimental results are given to verify the validation of the proposed method.

Tracking control of the direct-drive robot manipulators in high-speed is a challenging problem. The Coriolis and centrifugal torques become dominant in the high-speed motion control. The dynamical model of the robotic system including the robot manipulator and actuators is highly nonlinear, heavily coupled, uncertain and computationally extensive in non-companion form. In order to overcome these problems, this paper presents a novel adaptive control for direct-drive robot manipulators driven by Permanent Magnet Synchronous Motors (PMSM) in tracking applications. The novelty of this paper is that the proposed adaptive law is free from manipulator dynamics by using the Voltage Control Strategy (VCS). Additionally, a state space model of the robotic system driven by PMSM is presented. The VCS differs from the commonly used control strategy for robot manipulators the so called torque control strategy. The position control of the PMSM is effectively used for the tracking control of the robot manipulator. This idea takes the control problem from the manipulator control to the motor control resulting in a simple yet efficient control design. Compared with the torque control, the control design is simpler, easier to implement with better tracking performance. The control method is verified by stability analysis. Simulation results show superiority of the proposed control to the torque control applied by field oriented control on the direct-drive robot driven by PMSM.

Due to emergence of serious obstacles to scaling of transistors' dimensions, it has been obviously proved that silicon technology should be replaced by a new one having a high ability to overcome the barriers of scaling to nanometer regime. Among various candidates, carbon nanotube (CNT) field effect transistors are introduced as the most promising devices for substituting the silicon-based technologies. Since the channel of these transistors is made of CNT then its properties, such as chiral vector, have prominent effects on determining the performance of devices. In this paper the CNT diameter impact on tunneling and thermionic emission (TE) currents of a coaxially-gated carbon nanotube field effect transistor (CNTFET) with doped source/drain extensions is investigated. The source/channel/drain of this transistor are a zigzag CNT with (n, 0) chirality. The “ n” value could be in the form of n = 3a + 1 or n = 3a + 2. By increasing the “ a” , the diameter increases while the energy band gap EG of the CNT decreases; as a result by increasing the “ a” value, the on/off current ratio decreases. However, for n = 3a + 2 the EG of a CNT shows a higher value; then at a given “ a” , for n = 3a + 1 the on/off current ratio may decrease due to a lower EG and hence higher tunneling and TE current. Generally, subthreshold swing improves and threshold voltage increases for a lower diameter device; consequently, the leakage current could diminish. ON-state current and output conductance have higher values for a higher diameter. Also, the difference between EG and hence the I-V characteristics of the device with n = 3a +1 and n = 3a + 2 is negligible for a higher diameter value. All the results are justified based on the energy-position resolved electron density and current spectrums on energy band diagram of the device.

In multi-echelon distribution strategy freight is delivered to customers via intermediate depots. Rather than using direct shipments, this strategy is an increasingly popular one in urban logistics. This is primarily to alleviate the environmental (e. g., energy usage and congestion) and social (e. g., trafficrelated air pollution, accidents and noise) consequences of logistics operations. This paper represents a two-echelon capacitated vehicle routing problem (2-ECVRP) in which customers' satisfaction and environmental issues are considered for perishable goods delivery for the first time. The paper proposes a novel bi-objective model that minimizes: 1) total customers waiting time, and 2) total travel cost. A restriction on maximum allowable carbon dioxide (CO2) emissions from transport in each route is considered as environmental issue in the problem. The proposed model is solved by simple additive weighting (SAW) method. Finally, the proposed model is applied to a real world problem in a supermarket chain. The results achieved by GAMS optimization software confirm the validity and high performance of the model in respect to the importance of the each objective function. Furthermore, the sensitivity analysis performed on the model reveals that less restrictive policies on carbon emissions lead to more total emissions but less total travel cost and customers waiting time.

This study seeks to develop a fuzzy expert system to help managers in assessing their effectiveness and position of their business on the manufacturing excellence track. Assessment process is multidimensional in nature and there is a relationship between the different variables of the system. In addition, both quantitative and qualitative variables as well as the uncertainty in the statements of experts must be considered in the evaluation process. Fuzzy DEMATEL technique complies with these requirements by respecting the interrelation between the factors and by converting the qualitative judgments into quantitative values for decision. Due to these features, this technique is used in this study as the best technique for developing the decision tool. Evaluation criteria were identified through a literature review and interviews with experts. Multiple pairwise comparisons were performed to determine the weights of these criteria. Then, these weights were used to build If-Then rules of decision system. This reduced the supernumerary rules of the system, and provided a more real If-Then rule base. The decision support tool, presented in this study, enables decision makers to assess manufacturing excellence from different aspects such as External Excellence (EE), Internal Excellence (IE) and Technological Excellence (TE). The results of the implementation of this fuzzy expert system in Zar-Macaron Company (as a case study) were satisfactory.

Sol-gel technique was used to coat multiwall carbon nanotubes (MWCNTs) with anatase titania to increasing the surface area and improve the photocatalytic activity of TiO2. Room temperature ballistic conduct of MWCNT combined with semiconducting behavior of anatase brought about a photocatalytic improvement of ~37 % with respect to the highest methyl orange decolorization flair. For characterization and photocatalytic efficiency determination, X-ray diffraction (XRD), field emission (FE) scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS) and ultraviolet visible (UV-vis) spectroscopy were rehearsed. Attachment of anatase nanoparticles onto 30 wt % functionalized CNTs resulted in 99. 72% methyl orange decolorization by 160 min irradiation with 8 W ultraviolet lamp. This value was fourfold greater than pure TiO2 nanoparticles and much greater than the values reported in the literature. This improvement was attributed to larger surface area, lower charge recombination and superior crystal structure and stimulated visible-light shifting due to presence of Ti ̶ O ̶ C bond.

This paper is an attempt to synthesize nanostructured tantalum films on medical grade AISI 316L stainless steel (SS) using pulsed DC plasma assisted chemical vapor deposition (PACVD). The impact of duty cycle (17-33%) and total pressure (3-10 torr) were studied using field emission scanning electron microscopy (FESEM), grazing incidence x-ray diffraction (GIXRD), nuclear reaction analysis (NRA), proton induced x-ray emission (PIXE) and Rockwell indentation methods. The optimized deposition conditions for making the best film characteristics in terms of deposition rate, purity and maximum α-phase was recognized. Also, the results showed that using a near stoichiometric TaN interlayer in this technique improves the film adhesion strength and considerably increases Ta film purity. The NRA analysis results indicated that the pulsed DC-PACVD is capable of producing Ta films with negligible amount of residual hydrogen which makes films needless to post bake treatment.

The world is looking towards producing products which consume less power without compromising on quality of life. The increase in use of refrigeration and air conditioning appliances are contributing to global warming. The world wide temperatures are shooting up at an increasing rate. This paper presents a design of roll bond evaporator as the heat exchanger to provide cooling in room air conditioner. Presently all room air conditioners use tube and fin evaporators. This study presents roll bond evaporator as a power saving alternative to tube and fin evaporator. The experimentation has been done and comparative study of roll bond evaporator with that of tube and fin evaporator is presented. It was found out that while the tube and fin evaporator took 30 minutes to get a uniform temperature of 25 º C in the room, the roll bond evaporator took only 25 minutes to get that uniform temperature, thereby saving 5 minutes of running of air conditioner.

The spacecraft simulator robust control through H∞-based linear matrix inequality (LMI) and robust adaptive method is implemented. The spacecraft attitude control subsystem simulator consists of a platform, an air-bearing and a set of four reaction wheels. This set up provides a free real-time three degree of freedom rotation. Spacecraft simulators are applied in upgrading and checking the control algorithms' performance in the real space conditions. The LMI controller is designed, through linearized model. The robust adaptive controller is designed based on nonlinear dynamics in order to overcome a broader range of model uncertainties. The stability of robust adaptive controller is analysed through Lyapunov theorem. Based on these two methods, a series of the laboratory and computer simulation are made. The tests’ results indicate the accuracy and validity of these designed controllers in the experimental tests. It is observed that, these controllers match the computer simulation results. The spacecraft attitude is converged in a limited time. The laboratory test results indicate the controller ability in composed uncertainty conditions (existence of disturbances, uncertainty and sensor noise).

A thermosyphon is an efficient heat transfer device, which transports heat using gravity for the evaporation and condensation of the working fluid. In the present study the Box-Benhnken (BBD) design approach was chosen for the Two-Phase Closed Thermosyphon (TPCT) with CeO2 nanofluid using 0. 1% volume of Nanofluid with surfactant of ethylene glycol. The experiment resulted in identifying the optimised set of parameters for 405SS TPCT, to achieve lower thermal resistance and better heat transfer. This work gains significance in the sense that with the number of experiments, reliable model has been generated validated and further, the process has been optimised with one objective which is thermal resistance. To obtain the optimum condition, the response surface methodology (RSM) through Box – Behnken (BBD) was applied.

One of the most famous methods to predict the stiffness of short fiber composites is micromechanical modeling. In this study, a Representative Volume Element (RVE) of a beech wood flour natural composite has been designed and the orientation averaging approach has been utilized to predict its stiffness tensor. The novelty of this work is in finding the proper fiber orientation distribution function to increase the precision of the stiffness prediction of this kind of natural composites. The predicted results for stiffness with the micromechanical modeling are compared to the experimental test results and FEM results of beech wood flour/polypropylene composite.

The basic aim of present study is to examine the effect of main friction stir welding (FSW) parameters on the quality of AA 6063 plate welds. Welding of AA6063 was carried out by a vertical milling machine, using different tools with a stationary shoulder and during the welding no external heating system was used. Different welding parameters studied were the tool rotational speed which varied from 2700 to 5400 (rpm), the traverse speed of table which varied from 12 to 17 (mm/min), and the tool shoulder diameter ranging from 17 to 22 mm. In the present research three levels, three factorial designs were used for optimization by taguchi approach. The results indicated that tensile strength of welded joint was increasing with rotational speed and decreasing with increasing transverse feed because frictional heat was directly proportional to rotational speed of tool.

This paper proposes a reduct construction method based on discernibility matrix simplification. The method works with genetic algorithm. To identify potential problems and prevent complete failure of bearings, a new method based on rule-based classifier ensemble is presented. Genetic algorithm is used for feature reduction. The generated rules of the reducts are used to build the candidate base classifiers. Then, several base classifiers are selected according to their diversity and the scale of them. Weights of the selected base classifiers are calculated based on a measure of support rate. The classifier ensemble is constructed by the base classifiers. The accuracy reached 98. 44% which is 4. 5% higher than that of the three base classifiers.

Aim of the project is efficiency increase of hard rocks destruction at borehole bottom by developing drilling mud solution and evaluation of its influence on drilling process. The article presents the results of studies directed on studying of drilling mud composition (the choice of reagent concentrations, taking into account the filtration properties, structural and rheological parameters, study of the temperature effect influence on the quality of the solution). Experiments of metallic indenter penetration into the glass sample at various number of strikes in the water and surfactant solutions are presented in the article. Paper also offers investigation devoted to development of clayless mud solution with surfactant addings, which will allow increase of hard rocks destruction efficiency. Results of industrial test trials of developed mud solution are also represented, showing implementation of developed drilling mud composition to increase productivity of drilling operations by maintaining high drilling speed and advance per bit.