Effect of plasma treated sol-gel dielectric towards the morphology of pentacene

This paper discusses the effect of forming gas (93%N₂ + 7%H₂) plasma treatment for sol-gel methyl-silsesquioxane (MSQ) as a dielectric film towards the grain morphology of a solution processable pentacene. Atomic force microscopy and X-ray diffractometer results confirm that a brief (10 s) plasma treatment for MSQ increases the grain size of pentacene and encourages its growth in thin-film phase. This paper also demonstrates that the presence of large Si(CH₃)₃ bonds on the MSQ surface are very important to encourage the growth of pentacene’s molecules in thin-film phase. In addition, this paper also suggests that there is no strong relationship between the grain size and ordering of pentacene molecules.     

Sensitivity Analysis of the GIUH based Clark Model for a Catchment

For estimation of runoff response of an ungauged catchment resulting from a rainfall event, geomorphologicalinstantaneous unit hydrograph (GIUH) approach is getting popularbecause of its direct application to an ungauged catchment. Itavoids adoption of tedious methods of regionalization of unithydrograph; wherein, the historical rainfall-runoff data of anumber of gauged catchments are required to be analyzed. In thisstudy, the GIUH derived from geomorphological characteristics ofa catchment has been related to the parameters of Clark IUH modelfor deriving its complete shape. The DSRO hydrographs estimatedby the GIUH based Clark model have been compared with the DSROhydrographs computed by the Clark IUH model option of the HEC-1package and the Nash IUH model by employing some of the commonlyused error functions. Sensitivity analysis of the GIUH basedClark model has been conducted with the objective to identify thegeomorphological and other model parameters which are moresensitive in estimation of peak of unit hydrographs computed bythe GIUH based Clark model. So that these parameters may beevaluated with more precision for accurate estimation of floodhydrographs for the ungauged catchments.     

Integrating Remote Sensing and GIS Techniques with Groundwater Flow Modeling for Assessment of Waterlogged Areas

False Colour Composites (FCC's) of IRS-1A LISS-II sensor pertaining to the dates 9th April 1989 and 7th December 1989 are used to delineate the pre-monsoon and post-monsoon surface waterlogged areas in a region around Habibpur sub-distributary bounded by Vaishali branch canal and Gandak river in North Bihar, India for the year 1989 using visual interpretation technique. Also, digital data of IRS-1C LISS-III sensor pertaining to the dates 7th December 1998 and 6th April 1999 are analyzed in a digital image processing software – ERDAS Imagine 8.3.1, to delineate the pre-monsoon and post-monsoon surface waterlogged areas for the year 1998–1999. Further, for the study area, the waterlogging conditions are delineated for the year 1991–1992 using the groundwater flow modeling software package, MODFLOW. The results obtained using satellite remote sensing data and groundwater flow modeling are integrated in a GIS environment in ERDAS Imagine for assessment of the waterlogging areas.     

Studies on efficiency of guava (Psidium guajava) bark as bioadsorbent for removal of Hg (II) from aqueous solutions

Biosorption of Hg (II) was investigated in this study by using guava bark powder (GBP). In the batch system, effects of various parameters like contact time, initial concentration, pH and temperature were investigated. Removal of Hg (II) was pH dependent and was found maximum at pH 9.0. Based on this study, the thermodynamic parameters like change in standard Gibb's free energy (DeltaG(0)), standard enthalpy (DeltaH(0)) and standard entropy (DeltaS(0)) were evaluated. The rate kinetic study was found to follow second-order. The applicability of Freundlich adsorption isotherm model was tested. The value of regression coefficient was greater than 0.99. This indicated that the isotherm model adequately described the experimental data of the biosorption of Hg (II). Maximum adsorption of 3.364 mgg(-1) was reached at 80 min. The results of the study showed that guava bark powder can be efficiently used as a low-cost alternative for the removal of divalent mercury from aqueous solutions.     

Extraction of road surface from mobile LiDAR data of complex road environment

Three-dimensional (3D) data of roadways are frequently used for extraction of detailed roadway information which is essential for several planning and engineering applications. Recent past has seen rapid growth in utilization of mobile LiDAR system (MLS) to acquire volumetric 3D data of roadway for this purpose. MLS data are capable of capturing highly detailed road information, which is useful for road maintenance and road safety operations. The existing literature shows that road environment complexity, unevenness, and absence of raised curb limit the extraction of road information from MLS data. It must be noted that a large number of roads, especially in developing world, are characterized by these complexities and thus raise the need for a technique which can work in these road environments. Considering the above, this paper proposes a method to extract road information, where road boundary is not geometrically well-defined. The proposed method is constructed using unstructured MLS data as input and does not require any other additional data. The method is divided into three major steps, that is, MLS data structuring and ground filtering, road surface point extraction, and road boundary refinement. The first step filters ground points from input MLS data, while the second step identifies road surface points from among the ground points. The second step is designed using specific characteristics of a road, that is, topology, surface roughness, and variation of point density. Third step refines road boundary. Three test sites, quite complex with heterogeneous characteristics, were used for demonstration of the proposed method. Road surfaces of these three roadways were accurately extracted without being affected by on-road objects and absence of raised curb. Average accuracy measures like completeness, correctness, and quality were found to be 93.8%, 98.3%, and 92.3%, respectively, in three test sites. Further, road boundaries of extracted road surfaces of these three test sites were refined at average completeness, correctness, and quality of 95.6%, 97.9%, and 93.7%, respectively. The proposed method has shown satisfactory performance for complex roadways having road section with and without raised curb, and has potential to be employed for such road environments, which are not uncommon. Proposed method was implemented on GPU-based parallel computing framework, which significantly saved the run time in processing of MLS data of three test sites.     

A two-stage algorithm for ground filtering of airborne laser scanning data

ABSTRACT

A two-stage algorithm is proposed in this article for ground filtering of airborne laser scanning (ALS) data. Input ALS data are initially preprocessed for outliers removal. The first stage removes the non-ground objects from preprocessed ALS data based on the geometrical reasoning, which is applied over piecewise local neighbourhoods around selected points. The second stage retrieved the ground points falsely recognized as non-ground in the first stage using geometrical similarity of ground points in their surroundings. The proposed algorithm was tested and validated comprehensively using complex and heterogeneous landscapes of selected 10 ALS data sets and additional 15 International Society of Photogrammetry and Remote Sensing data samples. The ground points were filtered out in these data sets and data samples at average total error and kappa coefficient of 3.66% and 89.15%, respectively. The proposed algorithm performs satisfactorily in the complex terrain cases such as mixed vegetation and houses on sloping terrain, low vegetation, complex objects, low and small objects, scene border, and discontinuity. The proposed algorithm is straightforward and, consequently, computationally efficient. Thus, it has potential for wider use in industry.     

A septic tank‐UASB combined system for domestic wastewater treatment: a pilot test

A 250 L and a 550 L pilot scale Up‐Flow Anaerobic Sludge Blanket (UASB) reactors having different reactor height were fed septic tank effluents and operated at ambient temperatures of 0°C to 30°C. Both UASB reactors were fed intermittently at least 8 times per Hydraulic Retention Time (HRT) and the performance was monitored at 4d and 1d HRT. The removal efficiencies of Total Suspended Solid (TSS) and Total Chemical Oxygen Demand (COD_t) were about 59–68% and 54–59%, respectively, for both reactors at both HRT. The TSS and CODt removal efficiencies of Septic tank – UASB combined system were above 80% for both HRTs tested. The average biogas yields were almost same at 4d and 1d HRT, representing 31(±3)% of influent CODt. The nitrogen and phosphorous removal efficiency was an average 20–30%. The tested system can become a suitable low cost yet effective option.