Manish Pal

Enhanced Adsorption of Hexavalent Chromium onto Magnetic Calcium Ferrite Nanoparticles: Kinetic, Isotherm, and Neural Network Modeling

Calcium ferrite nanoparticles with super-paramagnetic behavior were synthesized via simple chemical precipitation method for effective removal of hexavalent chromium from aqueous media. The properties of synthesized nanoparticles were studied by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), and vibrating sample magnetometer (VSM) measurements. The ferrite nanoparticles have shown polycrystalline nature and high BET specific surface area (229.83 m2/g) with active functional groups on the surface. The adsorption process follows second-order kinetics with the involvement of intra-particle diffusion and adsorption capacity as much as 124.11 mg/g was determined from the Langmuir isotherm. The thermodynamic analysis revealed that the adsorption process was feasible, spontaneous, and exothermic in nature. A three-layer feed-forward back-propagation artificial neural network (ANN) model was employed to predict the removal (%) of Cr(VI) ions as output. Optimal ANN network (4:8:1) shows the minimum mean squared error (MSE) of 0.00161 and maximum coefficient of determination (R2) of 0.984. The adsorption process is mostly influenced by solution pH and followed by adsorbent dosage, initial Cr(VI) concentration, and contact time as illustrated by sensitivity analysis. With small size and high surface area, biocompatibility, ecofriendly nature, easy magnetic separation, and enhanced adsorption capacity towards Cr(VI), calcium ferrite nanoparticles will find its potential application in wastewater remediation. GRAPHICAL ABSTRACT

Evaluation of speed–flow characteristics on two-lane highways with mixed traffic

AbstractThe HCM (Highway Capacity Manual 2010) classifies two-lane rural highway that passes through developed areas as ‘Class III’ and suggests using Percent Free-Flow Speed (PFFS) as performance measure to define Level Of Service (LOS). Apparently, this performance measure addresses the main limitation associated with using Average Travel Speed (ATS) as a measure of performance. However, larger speed differential under heterogeneous traffic causes error in estimating Free-Flow Speed (FFS) and thus affects PFFS. This implication was examined in the present study using field data collected on a national highway approaching a city. Speed–flow equations were developed and intercept values were compared to the FFS obtained according to HCM guidelines. Comparison confirms a very close agreement between average FFS value and those obtained for different types of vehicle separately except for car. This consequently causes an error in estimating PFFS since the traffic composition consists of significant proporti...

Analysis of slope considering circular rupture surface

Determination of stability under seismic loading condition of soil slope is one of the important findings for geotechnical engineers. Here, in this paper, a homogeneous soil slope considering circular failure surface has been analyzed under the influence of pseudo-dynamic inertia forces and surcharge load by limit equilibrium method. The Fellenius line is used to locate the center of most critical circle and factor of safety has been found through the application of force equilibrium. The effects of variation of parameters such as horizontal and vertical seismic accelerations, soil friction angle and slope angle on factor of safety are presented.

A Cognitive Approach in Selection of Source for Water Treatment Plant based on Climatic Impact

The importance of finished water quality from water treatment plants (WTP) is manifold due to its direct impact on consumer health. It is observed from recent studies that change in climatic pattern can affect the concentration of various water quality parameters (WQP) at source itself and change in source water quality may adversely affect the efficiency of WTP also. In the present study Analytical Hierarchy Process (AHP) is utilized to prioritize WQP based on its vulnerability towards climate change. A feed-forward, fully-connected, three-layer neural network model is developed to compute the Vulnerability Index (VI) with the priority vectors of the WQP as determined by AHP approach. The model is utilized to predict the overall vulnerability of three different surface water sources namely river water, lake water and wetland water. The proposed AHP-Neural network model shows that River water is least affected due to climatic abnormalities with minimum VI value and may be considered as the best source water for WTP among the three considered alternatives. The sensitivity analysis of the new model is also carried out. Hence, this proposed model may become a reliable tool to the water supply engineers in the coming days of climate change.

Preferred time headway of drivers on two-lane highways with heterogeneous traffic

Abstract This paper presents an investigation on the adequacy of one of the major performance indicators for two-lane highways, the percent-time-spent-following (PTSF) under changing driver’s behavior in choosing headways. Field study was conducted on a two-lane highway in India that exhibits heterogeneity in its traffic composition and a wide range of flow levels was covered while collecting data. The appropriate headway distributions were selected based on goodness-of-fit test. Exponential or Erlang distributions exhibit their aptness in describing headways up to a volume to capacity ratio of 0.3 and gamma and exponential distributions were compatible for headway data corresponding to a volume to capacity ratio of 0.4 and above. Around 40% drivers were observed to adopt headways 2 s or less at heavy flow when a car-following situation prevails; these headways are considered unsafe in several instances. Further, speed–headway relationships were established to assess a headway threshold beyond which vehicles could be considered free. Empirical investigation indicates a value of about 6 s under such traffic unlike 3 s as considered in PTSF estimation. Another major implication on PTSF is a few drivers move in a platoon by choice even if they have a gap of more than 6 s and passing opportunities.

Analysis of slope using modified pseudo-dynamic method

Seismic design of slope is an important aspect in earthquake-prone areas to resist devastation due to earthquake load. This study presents the seismic stability analysis of homogeneous soil slope in which modified pseudo-dynamic method adopting limit equilibrium approach has been used. Results are presented in tabular form, which will serve as essential design parameters. Parametric studies show effects of soil properties and seismic forces on safety of slope. In addition, the required reinforcement strength against failure under seismic loading is evaluated and presented in figures that are useful to design reinforced slope.

Seismic stability of slope using modified pseudo-dynamic method

Abstract The paper presents evaluation of factor of safety of slope assuming circular failure surface under seismic loading condition. The centre of most critical circle is located using Fellenius method. Adopting limit equilibrium method, under the influence of weight of potential sliding mass and seismic inertia forces, factor of safety is evaluated applying new pseudo-dynamic method based on visco-elastic behaviour of soil which satisfies zero-stress boundary condition and considers soil amplification inherent to soil properties. Results are presented and compared with available results from literature. Detailed parametric studies are also carried out to observe the variation of safety factor at different soil strength and seismic forces and these can serve as very good criteria for design of slopes.

Development of performance index for evaluation of small scale hydro power plants by neural network and multi criteria decision making

In recent years the small scale hydro-power projects have emerged as a viable and less-expensive alternative to conventional energy sources. The suitability of such projects in a given location must be analyzed based on site-specific factors, and this is often performed with the assistance of MCDM methods, of which, FLDM models are the widely applied. However, both methods have their drawbacks. FLDM is known for its ‘haziness’ when converting its fuzzy rating into a crisp rating, while random selection of weight vector for attributes becomes a major problem and ANN to predict the index through the weight function. If fuzzy logic is used to determine the weight vector to be assigned to the criteria considered for a certain decision-making problem, the output of the result will be more logical and the haziness of the conversion to a crisp rating will not influence the decision. Thus, we investigated a hybrid FLDM method to identify the most suitable location for a small scale hydro-power project. The index ...

Study on Plastic Coated Overburnt Brick Aggregate as an Alternative Material for Bituminous Road Construction

There are different places in India where natural stone aggregates are not available for constructional work. Plastic coated OBBA can solve the problem of shortage of stone aggregate to some extent. The engineers are always encouraged to use locally available materials. The present investigation is carried out to evaluate the plastic coated OBBA as an alternative material for bituminous road construction. Shredded waste plastics are mixed with OBBA in different percentages as 0.38, 0.42, 0.46, 0.50, 0.54, and 0.60 of the weight of brick aggregates. Marshall Method of mix design is carried out to find the optimum bitumen content of such bituminous concrete mix prepared by plastic coated OBBA. Bulk density, Marshall Stability, flow, Marshall Quotient, ITS, TSR, stripping, fatigue life, and deformations have been determined accordingly. Marshall Stability value of 0.54 percent of plastic mix is comparatively higher than the other mixes except 0.60 percent of plastic mix. Test results are within the prescribed limit for 0.54 percent of plastic mix. There is a significant reduction in rutting characteristics of the same plastic mix. The fatigue life of the mix is also significantly higher. Thus plastic coated OBBA is found suitable in construction of bituminous concrete road.

Seismic Stability of Slope Considering Rayleigh Wave

ABSTRACT In the present paper factor of safety of slope under seismic loading condition is evaluated assuming circular failure surface. Using Fellenius method the center of most critical circle is located. Adopting limit equilibrium method, under the influence of weight of potential sliding mass and seismic inertia forces, factor of safety is evaluated considering Rayleigh wave along with primary wave and shear wave. Results are presented and compared with the available results from literature. Detailed parametric studies are also carried out to observe the variation of safety factor at different soil strength and seismic forces.