International Journal of Engineering
Volume:32 Issue: 5, May 2019

Polychlorinated biphenyls (PCBs) cause many significant ecological problems because of their low degradability, high harmfulness, and solid bioaccumulation.Two bacterial strains were isolated from soil that had been polluted with electrical transformer liquid for more than 40 years. The isolates were distinguished as Lysinibacillus macrolides DSM54Tand Bacillus firmus NBRC15306Tthrough 16S rRNA sequencing analysis.This is the primary report of an agent of the genus Bacillus firmus equipped for the removal of PCBs. The strains could develop broadly on 2-Chlorobiphenyl and 2,4-dichlorobiphenyl. GC/MS analysis of individual congeners revealed up to 80% degradation of the xenobiotics in 96h, attendant with cell proliferation of up to two orders of extent. More extensive investigation of the isolates may be helpful in surveying detoxification forms and in planning bioremediation and bioaugmentation strategies.

This research evaluated the efficiency of combined anaerobic-aerobic processes for the treatment of slaughterhouse wastewater. The anaerobic reactor consists of a 3.95 L Plexiglas column with 60 mm diameter and 140 cm height. The cylindrical particles of polyvinyl chloride with 2 mm diameter and 1250 kg m-3 density packed to 60 cm of column were used as biomass saving material. The designed aerobic reactor also has a Plexiglas column with 10 cm internal diameter, 90 cm height and 60 cm useful height. Anaerobic fluid bed and aerobic mobile bed reactors were exploited for retention times of 18, 24, 32, 40 and 48 h. The efficiency of total suspended solids, biological oxygen demand and chemical oxygen demand removing were evaluated in different stages. Under the applied condition, chemical oxygen demand, biological oxygen demand and suspended solids were removed by 85.94, 92 and 66%, respectively. Maximum methane production of 3765 mL per day was obtained after 31 h at the residence time of 18 h. The anaerobic reactor plays very important role in reduction of the chemical oxygen demand, and the aerobic reactor is necessary to clear the anaerobic treated wastewater and ensure the quality of the final waste.

A special sensitive element based on the novel composite material was created. The sensor has a linear calibration and is resistant to aliphatic hydrocarbons, in particular aviation fuel. A low cost and easy-to-implement method for calibrating the sensor was proposed. Temperature dependence of the oxygen mass transfer coefficient kL was measured for aviation fuel TS-1 (Russian equivalent of Jet A-1) in the temperature range of 10 to 40 °C as a demonstration of the sensor capabilities. The dependence found obeys the Arrhenius equation with the parameters EA = 21.7 ± 1.5 kJ/mol, kL0 = 1080 ± 90 m·h-1. The resistance to mechanical action is one of the important advantages over the sensor made of a sol-gel matrix with a protective coating. Damage to some part of the surface does not change the properties of the entire sensor, since the composite material contains a large number of isolated particles with a dye.

Makassar is one of the metropolitan cities located in Indonesia which recently experiences massive an increased construction because of population growth. Mapping the spatial distribution and development of the built-up region is the best method that can use as an indicator to set the urban planning policy. The purpose of this study is to identify changes in land use and density in Makassar City that occurred in 2013 and 2017 primarily for built areas, including settlements using optical data, especially Landsat data. The data analyzed by using multi-temporal Landsat OLI 8 data taken from 2013 to 2017. Normalized Difference Built-Up Index (NDBI), Urban Index (UI) and Normalized Difference Vegetation Index (NDVI) are the spectral indices produced from Landsat OLI band covering Short Wave Infrared (SWIR) wavelength, visible Red (R) and Near Infrared (NIR) areas that can be revealed by examining changes in land use and area cover. The result shows that both spectral indices namely NDBI and UI indicate an increased built-up area approximately 18 and 6%, respectively over four years. Also, based on NDBI reveals that most an increased built-up area distributes in the north of Makassar (Biringkanaya sub-district), meanwhile UI shows that Biringkanaya and Manggala sub-districts experience an increased built-up area. The development of the city will also never be separated from the history of city growth, current conditions, and the growth of the town to come. The phenomenon of the development of the town will include the development of city elements in detail, aspects of the shape of the town and the development of city regulations.

This paper summarises the impact of major earthquakes, 2010–2011, on Christchurch’s water supply network and what recovery measures have been applied, what worked well, what did not and why. A number of issues related to the open nature of the Christchurch water supply network were identified during earthquakes. It was difficult to manage large water supply pressure zones during the post-earthquake emergency response due to multiple failures of assets. The performance of the post-earthquake, post-rebuild 2017 water supply network was compared with the pre-earthquake water supply network to investigate the success of the post-earthquake rebuild programme. A multi-million dollar repair and rebuild works helped to return the level of service of the network to the pre-earthquake level and the water leakage of the 2017 water supply network was found similar to the pre-earthquake level. Hydraulic model was used for immediate earthquake emergency response, what/if scenarios investigations and earthquake damage assessments. Hydraulic models were built for pre and post-earthquake water network of Christchurch. The performance of pre and post-earthquake hydraulic models were compared and the results are also reported in this paper. Hydraulic modelling was found to be a very powerful tool engineers can use to assess the impact of an earthquake on a water supply network and formulate alternative plans during emergency response.

The desired gap headway of drivers, while close following, represents the main parameter in determining the following distance between vehicles.  This paper uses the raw individual vehicles data taken from loop detectors for millions of vehicles used M25 and M42 in order to estimate the gap headway distributions between successive pairs of vehicles.  The data used in this paper were filtered so as to focus on the cases of close following behavior only and more than quarter million pairs of close following cases is used to presents the results.  Such huge sample size taken from loop detectors will increase the results reliability as previous research used limited sample size. The results presented the cumulative distribution of drivers’ gap headway and suggested that the mean gap headway of drivers is about 1.1 s with standard deviation of 0.42 s.   The lane choice found to be significantly influencing the desired gap headway for speed higher than 70km/h only. The effect of the follower vehicle type of the desired gap headway was also examined and the results suggested that such effect is insignificant.  The findings of this paper are suggested to be used as inputs for traffic micro-simulation models.

In this study, fuzzy logic was implemented to formulate the fuzziness of layer boundaries for a two-layered clay soil. A field of two-layered clay with fuzzy boundaries between layers was generated, and then the bearing capacity of strip footing on this field was calculated by the assumption of plane-strain conditions. The Mohr-Coulomb failure criterion was used and bearing capacity calculations were based on finite difference method. The effect of fuzziness in layer boundaries was investigated for the case of strong-over-weak clay. It is concluded that the analyses by applying fuzzy boundaries yielded more conservative results than classical two-layered bearing capacity calculations when the ratio of thickness of upper layer to the width of footing exceeds 1.  When the ratio of thickness of upper layer to the width of footing is lower than 1, the bearing capacity of footing on two-layered clay is higher by considering fuzzy boundaries.

The major decision in construction process involves the selection of suitable site with best soil conditions, as structure resides in the soil. Most problematic soils like expansive soils hardly proved to be the best engineering subgrade profile for pavement constructions. Thus, this has undeniably led to the soil improvement options accompanying the reduction in resource depletion and solid waste management. Therefore, soil stabilization technique opted in the treatment of expansive soils. In concern of all these facts in this study, an effort was made in investigating the viability of utilizing industrial waste Ground Granulated Blast furnace Slag (GGBS) and agricultural waste Groundnut Shell Ash (GSA) as stabilizing agents. Two soils of different swell characteristics were treated with varying percentages of GGBS (2.5, 5, 7.5, and 10%) and GSA (2, 4, 6, 8, and 10%) at different curing periods of 28 and 60 days. The ascending behaviour of strength was experimentally analyzed by conducting Unconfined Compressive Strength and California Bearing Ratio (CBR) tests. The uptrend in peak stresses coupled with improved CBR value implicated the efficacy of cost-effective waste materials in ascending the strength nature of the soil, thereby amplifying the growth of construction sector. Thus, this study catalyzed in enhancing the bearing strength of clayey soil; in this manner making it well suitable for multitudinous geotechnical applications.

The performances of cementitious materials as well as the efficiency of construction are adversely affected at high temperatures. Previous studies have already demonstrated that ultra-fine (alccofine) material accelerates the hydration of cement particles and subsequently improves the mechanical and durability properties of the concrete at normal temperature. Moreover, at higher temperatures the performance of the concrete with the addition of alccofine is still unknown. This paper presents the effect of analytical properties of concrete with alccofine (25%) as a replacement of cement for various W/B ratios (i.e. 0.38, 0.4 and 0.45). The effect of addition of alccofine dosage on the thermogravimetric analysis was carried out in which not only mass loss and decomposition of hydration products from concrete with respect to temperature was found but also bound water (%) and calcium hydroxide (%) present in the concrete were determined. From X-ray diffraction it was observed that alccofine improved the formation of calcium silicate hydrate and calcium silicate aluminum hydrate in concrete and scanning electron microscope (SEM) analysis showed the formation of ettringite needles and calcium silicate hydrate in voids which made concrete denser. Therefore, it was concluded from this study that alccofine can be used as a viable substitute to cement in normal concrete considering its positive effects on property enhancement and an eco-friendly product.

The increase of shear strength in soil, reinforced with the geogrid (alternate reinforcer), is resulted from an increase of modulus of soil hardness, and also from the tensile strength of reinnforcer. The shear strength of contact surface in soil appears due to both the friction strength against the contact surface, and the passive strength formed in front of the elements of the geogrid system. In the clay reinforced with a geogrid, the resistance of the contact surface is low; therefore, contact surface rupture occurs before the tensile strength reaches the ultimate limit. Also, the geogrid is almost ineffective in limiting particles movement and creating passive resistance in clay, due to a big difference in the sizes of geogrid opening (a perture) comparing to clay grains. In this research, we tried to examine the effect of geotextile layers around the geogrid aimed to improve the soil-geogrid interaction in different drainage conditions by means of triaxle (UU) and (CD) trials on a large scale. Experiments were carried out, based on non-reinforced samples, geogrid-reinforced samples and geocomposite reinforced samples. The results of the experiments showed that the geotextile layers around the geogrid in the clay reinforcements not only effectively improved the interaction of contact surface, where the stresses are concentrated on the geogrid, but enhanced the shear strength parameters, the consolidation and drainage processes, as well. Radiographic results taken from fractal samples indicated that the rupture plate gets a reflection state in the reinforcing elements at the location of geocomposite configurations only, relative to the reinforcing elements. Meanwhile, the geogrid layers did not have any impact on the changes of rupture surface situation.

This paper analyzes an induction motor with high temperature superconducter (HTS) coated slotted solid rotor. By slotting the solid rotor, the electromagnetic torque near synchronous speed will increase but the starting torque will decrease. To improve starting torque, rotor slots are coated with HTS materials. Using HTS material vary the rotor resistance to great extends in starting step and this means the starting torque will be maximized. Also the torque near synchronous speed will be higher than before because of the resistance of the HTS is completely zero in this period. This would help the torque become more than the case without any coating. It is concluded that, HTS coating of slotted solid rotor will increase the starting torque by 42 and 74% than smooth type rotor and slotted one, respectively. For case-study motor, the torque near synchronous speed these improvements were 75% and 33%, respectively. The performance of the proposed motor is simulated using finite element method (FEM).

This study presents a modified transient current limiter (MTCL) for mitigation the inrush current of transformers. The MTCL is based on conventional transient current limiter (TCL), which, its configuration is modified to overcome the TCL drawbacks of operation. The proposed MTCL offers lower power losses and voltage/current THD during normal operation mode. It needs only one limiting reactor instead of two limiting reactors, which results in cost saving. The theoretical analysis of the MTCL for suppressing the inrush current has been presented and the performance was tested by PSCAD/EMTDC simulation anda experimental prototype. Both simulation and experimental results showed that the MTCL is effective for suppressing the transformer inrush current. Also, the capability of the MTCL for suppressing the transformer inrush current was compared with the conventional TCL.

This paper presents a temperature compensation voltage controlled oscillator (VCO) based on Cross-Coupled pair and Colpitts structures which is suitable for military fields. Also, two inductors have been used for increasing the negative conductance. By using this method, start-up condition has been improved. Two varactors and a simple capacitor bank are applied for covering a wide tunning range. The VCO has been designed and simulated in TSMC 0.18 µm CMOS technology.To compensate the frequency drift over a temperature range, MOS varactors are used and biased with a complementary to absolute temperature (CTAT) voltage reference. This CTAT voltage reference has been applied to two varactors and decreased the frequncy drift over temperature range. By using this technique, the proposed VCO can achieve a very stable frequency of 11.5 PPM/°C at 24.35 GHz over a temperature range of -40~120 °C. Simulation results also show the VCO covers the frequency range of 23.75~24.8 GHz. The simulated phase noise of center frequency is -102.6 dBc/Hz at 1 MHz offset frequency. The VCO consumes 10.4 mW DC power under 1.8 V supply voltage. The figure of merit of the VCO is -179.8 after compensating.

This paper introduces a peculiar approach of designing Static Random Access Memory (SRAM) memory cell in Quantum-dot Cellular Automata (QCA) technique. The proposed design consists of one 3-input MG, one 5-input MG in addition to a (2×1) Multiplexer block utilizing the loop-based approach. The simulation results reveals the excellence of the proposed design. The proposed SRAM cell achieves 16% and 15% improvement in terms of total number of Cell counts and Area. Similarly, the proposed design structure realizes the overall power dissipation savings up to 35.3% at maximum energy dissipation of circuit, 38.6% at average energy dissipation of circuit, 36.1% at minimum energy dissipation of circuit, 36.4% at average energy dissipation of circuit and 40.1% at average switching energy dissipation compared to the latest reported designs. The power analysis and structural analysis of the proposed design is compared with its state-of-the-art counterpart designs, using QCAPro and QCADesigner 2.0.3 tools. The proposed QCA based SRAM cell design can be taken as a base design in building an ultra-low power information generating systems like Microprocessors.

In this paper, for the first time, the subject of change point estimation has been utilized in the stationary state of auto regressive moving average (ARMA) (1, 1). In the monitoring phase, in case the features of the question pursue a time series, i.e., ARMA(1,1), on the basis of the maximum likelihood technique, an approach will be developed for the estimation of the stationary state’s change point. To estimate unidentified parameters following the change point, the dynamic linear model’s filtering was utilized on the basis of the singular decomposition of values. The proposed model has wide applications in several fields such as finance, stock exchange marks and rapid production. The results of simulation showed the suggested estimator’s effectiveness. In addition, a real example on stock exchange market is offered to delineate the application.

In this paper, an interval-valued Pythagorean triangular fuzzy number (IVPTFN) as a useful tool to handle decision-making problems with vague quantities is defined. Then, their operational laws are developed. By introducing a novel method of making a decision on the concept of possibility theory, a multi-attribute group decision-making (MAGDM) problem is considered, in which the attribute values are expressed with the IVPTFN and the information on the decision makers’ (DM) weights is completely unknown. Two novel forms of a multi-attributive border approximation area comparison (MABAC) technique are proposed to solve the problem. One of them is applied to compute the weights of the decision makers, and the other is used to rank the preference order of alternatives, that is based on the possibility expected value and standard deviation and has no aggregation of information. Finally, to illustrate the practicality and effectiveness of proposed method in real-world problems, the proposed method is applied in a real case study of an Iranian transport complex to sustainability assessment of its transport projects.

During recent years there has been growing interest in unmanned aerial vehicles (UAVs). Moreover, the necessity to control and navigate these vehicles has attracted much attention from researchers in this field. This is mostly due to the fact that the interactions between turbulent airflows apply complex aerodynamic forces to the system. Since the dynamics of a quadrotor are non-linear and the system is a multivariable one, moreover, it has six degrees of freedom for only four control inputs, then it is an under actuated system. This is why conventional control algorithms employed to track desired trajectories of fully actuated aerial vehicles are no longer applicable for quadrotors. The main step in the manufacturing of a fully autonomous unmanned aerial vehicle is to design a controller which stabilizes the aerial vehicle in the presence of uncertainties and disturbances, then navigate it along a desired trajectory. The aim of this study is to design and implement an intelligent controller for station keeping, attitude control, and path tracking of a quadrotor. For this purpose, an artificial neural network method was employed. The artificial neural network is one of the most powerful and useful tools in the modification of a control system. In this study, the control methods conventionally applied to quadrotors are reviewed at first. Then, in order to analyze the behavior of the system and also to design the controller, the state equations of a quadrotor are discussed. Following that, the design of a recurrent neural network based non-linear PID control algorithm is presented. Finally, the results of the simulation performed are presented, and the performance of the proposed algorithm are investigated. It was shown that by using the proposed algorithm, the quadrotor tracks the desired trajectory, and simultaneously, its attitude is stabilized.

Two stages gas guns are used for various purposes, particularly for mechanical characterization of materials at high rate of deformations. The performance of a two stages gas gun is studied in this work using the theory of the two-stage gas gun proposed by Rajesh, numerical simulation using combined Eulerian/ Lagrangian elements in Autodyna commercial code and experiment using a two stage gas gun developed by the authors of this study. Equations governing the motion of the piston and projectile are solved using Runge-Kutta method. The effects of parameters such as chamber pressure, pump tube pressure and piston mass on the performance of gun are explored. The results of numerical simulation and analytical methods are validated by experiment. Finally, a comparison between the analytical, numerical and experimental results shows that the theory proposed by Rajesh, yields reasonable predictions for the two stage gas gun performance in the first place, and Autodyn software, using combined Eulerian/ Lagrangian elements, gives accurate estimations for gas gun parameters, in the second place. A 3-D working diagram is provided for prediction of projectile velocity for any state of pump and chamber pressures which are the most important variables for a gas gun with a fixed geometry. Two stages gas guns are used for various purposes, particularly for mechanical characterization of materials at high rate of deformations. The performance of a two stages gas gun is studied in this work using the theory of the two-stage gas gun proposed by Rajesh, numerical simulation using combined Eulerian/ Lagrangian elements in Autodyna commercial code and experiment using a two stage gas gun developed by the authors of this study. Equations governing the motion of the piston and projectile are solved using Runge-Kutta method. The effects of parameters such as chamber pressure, pump tube pressure and piston mass on the performance of gun are explored. The results of numerical simulation and analytical methods are validated by experiment. Finally, a comparison between the analytical, numerical and experimental results shows that the theory proposed by Rajesh, yields reasonable predictions for the two stage gas gun performance in the first place, and Autodyn software, using combined Eulerian/ Lagrangian elements, gives accurate estimations for gas gun parameters, in the second place. A 3-D working diagram is provided for prediction of projectile velocity for any state of pump and chamber pressures which are the most important variables for a gas gun with a fixed geometry.

In this paper, the use of gasoline combinations with ethanol and nano oxide particles has been studied in gasoline-based SI EF7 engines. The mixtures are prepared in five emulsions of gasoline with 10% ethanol, gasoline with 10% ethanol and 10ppm nano Mn2O3, gasoline with  10% ethanol and 20ppm nano Mn2O3, gasoline with 10% ethanol and 10ppm nano Co3O4, gasoline with  10% ethanol and 20ppm nano Co3O4. An ultrasonic cleaner device is used to obtain a homogeneous gasoline combination with ethanol and additives of  nano oxides  during the test. To measure the output power of the engine, the Eddy current dynamometer has been coupled to the engine and to determine the emissions, an AVL gas analyzer is used. The results indicate that ethanol addition by 10% lead to 2.6% increase in brake power (BP), but interestingly 10 ppm Mn2O3  nano-additive raise the BP to 14.38% and 20 ppm nano-additive led to 19.56% increase of BP. While the BP with 10ppm and 20ppm nano-additives of  Co3O4 has increased by 7.96% and 11.5%, respectively. With regard to emissions, ethanol presence with nano additives in the blend reduces CO, UHC, and NOx whereas increases CO2. The best blend is gasoline-10% ethanol-20ppm Mn2O3.

This paper investigates the simulation of a hybrid desalination system composed of multi-effect evaporation with thermal vapour compression desalination (METVC) and reverse osmosis (RO) plant. The hybrid desalination system is also integrated with a gas turbine power plant through a heat recovery steam generator (HRSG). First, a comprehensive Thermodynamic model for HRSG, METVC, and RO are developed for predicting thermal behaviour of hybrid desalination system. Depending on the interconnection between input and output streams of METVC and RO, six configurations are proposed, and their results are compared in two different scenarios. In the first scenario, METVC desalination production is fixed at its maximum capacity of 70000 m3/day. The heat potential of power plants is fully extracted at maximum capacity of production of METVC. In the second scenario, METVC desalination production is not fixed. The limitation on the total production of the desalination plant (METVC+RO) is imposed as a constraint to the optimization problem. The results show that, regardless of the scenario under consideration, cconfiguration 1(the outlet water of the cooling system in METVC has been used for the feed water of the RO system) has the minimum energy consumption as well as maximum exergy efficiency.

This paper reviews existing studies and investigates thermal operational regimes of diamond bit during drilling operations. The operating temperature of the diamond core drill is studied under bench condition and an optimal thermal range are presented. Based on this study, it was noted that glazing of diamond tools is observed at temperatures less than 327°C, and normal wear of diamond tools is observed at temperatures within the range of 327- 660°C. Burning-in of diamond cores is accompanied by heating the matrix to temperatures above 800°C.

Filtration of the drilling mud is one of it's most important parameters, especially when drilling-in producing formation. Decrease of filtration characteristics allows reducing both solid and liquid phases's penetration zone into the formation. The study of the effect of the weighting-bridging agent's fractional composition on the filtration rate allows selecting of optimal composition of the solid phase in the the drilling mud. This paper presents studies of the static filtration rate of drilling mud with addition of various weighting-bridging agents. The obtained result indicates that an intensive decrease in the filtration rate is observed at calcium carbonate's introduction into the solution with an average particle size of up to 50 μm. Further studies should be directed to investigate the dynamic filtration rate, the possibility of "mixing" of various fractions in the composition of one solution and the evaluation of their influence on the filtration rate.