Comparative study on simultaneous leaching of nutrients during bioleaching of heavy metals from sewage sludge using indigenous iron and sulphur oxidising microorganisms

Pathak, A.,Singh, P.,Dhama, P.,Dastidar, M.G.,Kim, D.J.,Heyes, G. Maney Publishing 2014 Canadian metallurgical quarterly Vol.53 No.1

The present study investigated the changes in nutrient profile of sewage sludge during bioleaching in a batch mode of operation. The study identified the optimum bioleaching period at which maximum solubilisation of metals is achieved while maintaining the fertilising property of the bioleached sludge. The bioleaching experiments were performed using anaerobically digested sewage sludge by employing indigenous iron and sulphur oxidising microorganisms. The results showed that bioleaching using sulphur oxidising microorganisms is comparatively advantageous due to the higher solubilisation of heavy metals. However, despite its high potential in solubilisation of heavy metals from the sludge, the bioleaching process resulted in the undesirable dissolution/loss of sludge bound nutrients (nitrogen and phosphorus), thus making the sludge less attractive for land application as a fertiliser. After 16 days of bioleaching about 45% of the nitrogen and 34% of the phosphorus were leached from the sludge using indigenous iron oxidising microorganisms, whereas about 78% of the nitrogen and 56% of the phosphorus were leached using indigenous sulphur oxidising microorganisms. The findings indicated that the fertilising property of the sewage sludge can be maintained by conducting the process for a shorter duration of time (up to 10 days). The optimum bioleaching period was 10 days where about 85%Cu, 71%Ni, 91%Zn and 61%Cr were solubilised from the sludge while the loss of nitrogen and phosphorus was only 56 and 51% respectively, by using sulphur oxidising microorganisms. The heavy metals remaining in the bioleached sludge were mostly in the residual fraction ensuring the safe disposal of bioleached sludge for land application as a fertiliser.

Effect of Level of Concentrate Supplement on Blood Biochemical Changes and Testosterone Level in Crossbred (Bos indicusi×Bos taurus) Calves

Santra, A.,Agarwal, N.,Kamra, D.N.,Pathak, N.N. Asian Australasian Association of Animal Productio 1999 Animal Bioscience Vol.12 No.6

A growth study was conducted for 238 days in twenty crossbred cattle calves to observe the effect of dietary concentrate supplement on blood biochemical changes and serum testosterone levels. The calves were divided into four groups (A, B, C and D) of five animals each. Calves of groups A and B were fed 60% and 30% concentrate, respectively, supplying equal amount of protein along with wheat straw. The calves in group C received 30% concentrate in their diet for 1 to 119 days of experiment and 60% concentrate during 120~238 days of experiment and vice versa in group D. Mean DM and TDN intake were significantly higher in group A than group B, C or D, resulted in higher daily growth rate in the former group. Blood glucose level was significantly higher in group A where as blood urea, hemoglobin, total protein, albumin, and globulin levels remained unchanged among the groups. Serum testosterone level increased with the increasing age of the animals but the level remained same in the animals of group A, B, C and D. A 30% concentrate diet does not have any severe adverse effect on the performance of crossbred cattle.

EFFECT OF FUEL CHOICE ON NANOPARTICLE EMISSION FACTORS IN LPG-GASOLINE BI-FUEL VEHICLES

A. MOMENIMOVAHED,J. S. OLFERT,M. D. CHECKEL,S. PATHAK,V. SOOD,L. ROBINDRO,S. K. SINGAL,A. K. JAIN,M. O. GARG 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.1

Nanoparticle and gas-phase emission factors are presented for a liquefied petroleum gas (LPG) passenger vehicle and are compared to gasoline operation. A bi-fuel LPG-gasoline vehicle certified for use on either fuel was used as the test vehicle so that a direct comparison of the emissions could be made based on fuel choice. These values were considered along with previous studies to determine the relative change in particulate emissions due to fuel choice over a wide range of vehicles and operating conditions. The vehicle examined in this study was tested on a chassis dynamometer for both steadystate and transient conditions. Transient test cycles included the US FTP72 driving cycle, Japanese driving cycle and modified Indian driving cycle while steady-state tests were done at vehicle speeds ranging from 10-90 km/hr in various transmission gears. Exhaust particle size distributions were measured in real-time using a differential mobility spectrometer (DMS50), and particle number and particle mass emission factors were calculated. For both fuels, the majority of the particles ranged from 5 to 160 nm in terms of particle diameter, with typically more than 85% of the particles in the nucleation mode (between 5-50 nm). In most cases, the vehicle produced a greater fraction of larger (accumulation mode) particles when fuelled on LPG. Using the data in the literature as well as the data in the current study, gasoline fuel produces 4.6 times more particles in terms of number and 2.1 times more particles in terms of mass.

REAL-TIME DRIVING CYCLE MEASUREMENTS OF ULTRAFINE PARTICLE EMISSIONS FROM TWO WHEELERS AND COMPARISON WITH PASSENGER CARS

A. MOMENIMOVAHED,J. S. OLFERT,M. D. CHECKEL,S. PATHAK,V. SOOD,Y. SINGH,S. K. SINGAL 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.7

Two wheel vehicles (scooters and motorcycles) make up 74% of the vehicle population in India. Anexperimental study has been conducted to assess and compare the particulate emissions from several two wheelers andpassenger car in a typical Indian fleet. The vehicles, including four 4-stroke, two 2-stroke two-wheelers, and one gasoline-LPGbi-fuel passenger cars, were tested on a chassis dynamometer using the Indian Driving Cycle. A differential mobilityspectrometer was employed to measure the particle size distribution in real-time in the range of 5 nm to 560 nm. Particulatesize distributions from the two-wheelers were typically bi-modal. The count median diameter with 4-stroke two wheelers wasobserved in the range of 26 nm to 48 nm. The number and mass emission factors ranged between 9.5 × 1012 km−1 to 1.3 × 1013km−1 and 0.80 mg/km to 40 mg/km; respectively. In the case of 2-stroke two wheelers, it was observed that not only the countmedian diameter is 3 times larger compared to 4-strokes, but also 2-stroke vehicles produce 5 times more particles in term ofnumber and about 60 times more particles in terms of mass. The 2-stroke and 4-stroke two wheelers produced particulateemissions (both in terms of number and mass), which were higher than a gasoline and a LPG passenger vehicle operating onthe same driving cycle.

Effect of condensed tannins from Ficus infectoria and Psidium guajava leaf meal mixture on nutrient metabolism, methane emission and performance of lambs

A.K. Pathak,Narayan Dutta,A.K. Pattanaik,V.B. Chaturvedi,K. Sharma 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.12

Objective: The study examined the effect of condensed tannins (CT) containing Ficus infectoria and Psidium guajava leaf meal mixture (LMM) supplementation on nutrient metabolism, methane emission and performance of lambs. Methods: Twenty four lambs of ~6 months age (average body weight 10.1±0.60 kg) were randomly divided into 4 dietary treatments (CT-0, CT-1, CT-1.5, and CT-2 containing 0, 1.0, 1.5, and 2.0 percent CT through LMM, respectively) consisting of 6 lambs each in a completely randomized design. All the lambs were offered a basal diet of wheat straw ad libitum, oat hay (100 g/d) along with required amount of concentrate mixture to meet their nutrient requirements for a period of 6 months. After 3 months of experimental feeding, a metabolism trial of 6 days duration was conducted on all 24 lambs to determine nutrient digestibility and nitrogen balance. Urinary excretion of purine derivatives and microbial protein synthesis were determined using high performance liquid chromatography. Respiration chamber study was started at the mid of 5th month of experimental feeding trial. Whole energy balance trials were conducted on individual lamb one after the other, in an open circuit respiration calorimeter. Results: Intake of dry matter and organic matter (g/d) was significantly (p<0.05) higher in CT-1.5 than control. Digestibility of various nutrients did not differ irrespective of treatments. Nitrogen retention and microbial nitrogen synthesis (g/d) was significantly (p<0.01) higher in CT-1.5 and CT-2 groups relative to CT-0.Total body weight gain (kg) and average daily gain (g) were significantly (linear, p<0.01) higher in CT-1.5 followed by CT-1 and CT-0, respectively. Feed conversion ratio (FCR) by lambs was significantly (linear, p<0.01) better in CT-1.5 followed by CT-2 and CT-0, respectively. Total wool yield (g; g/d) was linearly (p<0.05) higher for CT-1.5 than CT-0. Methane emission was linearly decreased (p<0.05) in CT groups and reduction was highest (p<0.01) in CT-2 followed by CT-1.5 and CT-1. Methane energy (kcal/d) was linearly decreased (p<0.05) in CT groups. Conclusion: The CT supplementation at 1% to 2% of the diet through Ficus infectoria and Psidium guajava LMM significantly improved nitrogen metabolism, growth performance, wool yield, FCR and reduced methane emission by lambs.

Comparison of Meteorological Drought Indices for Different Climatic Regions of an Indian River Basin

Abhishek A. Pathak,B. M. Dodamani 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

Droughts being a regional phenomenon has a vicious impact on agricultural production as well as on the socioeconomic status of an area. Meteorological drought is not only the result of rainfall deficit but also influenced by temperature in the form of evapotranspiration. There are several indices that could assess meteorological drought. Because of the complex phenomenon underling in the interaction between climatic, hydrological and ecological variables hampers to ascertain the suitability of a drought index to a particular region. The present work aims to compare different meteorological drought indices for a given climatic condition at the regional level. The Standardized Precipitation Index (SPI), Reconnaissance Drought Index (RDI) and Standardized Precipitation Evapotranspiration Index (SPEI) were employed to study the variation of drought characteristics calculated from these indices. The study was implemented in the Ghataprabha river basin, which is one of the potential lands for agriculture in the basin of river Krishna. The study area possesses negative trends in rainfall and significant increasing trends in the temperature when tested with the Mann-Kendell trend test. Several drought events were observed through SPI, RDI, and SPEI over the basin. SPEI identified the highest number of drought events with high duration and severe intensity as compared to SPI and RDI. The alike performance was noticed between RDI and SPI whereas SPEI does not harmonize with them at any timescale of the study period. The study recommends to consider RDI and SPI in the humid (subhumid) region and SPEI at the semiarid (arid) region to assess the impact of drought effectively. The study also suggests to use an appropriate drought index for analysis of drought, which could lead to an adequate preparedness for the future drought hazards.

Maxima in the thermodynamic response and correlation functions of deeply supercooled water

Kim, Kyung Hwan,Spah, Alexander,Pathak, Harshad,Perakis, Fivos,Mariedahl, Daniel,Amann-Winkel, Katrin,Sellberg, Jonas A.,Lee, Jae Hyuk,Kim, Sangsoo,Park, Jaehyun,Nam, Ki Hyun,Katayama, Tetsuo,Nilsson, American Association for the Advancement of Scienc 2017 Science Vol.358 No.6370

<P><B>Pointing to a second critical point</B></P><P>One explanation for the divergence of many of the thermodynamic properties of water is that there is a critical point in deeply supercooled water at some positive pressure. For bulk water samples, these conditions are described as “no man's land,” because ice nucleates before such temperatures can be reached. Kim <I>et al.</I> used femtosecond x-ray laser pulses to probe micrometer-sized water droplets cooled to 227 K (see the Perspective by Gallo and Stanley). The temperature dependence of the isothermal compressibility and correlation length extracted from x-ray scattering functions showed maxima at 229 K for H<SUB>2</SUB>O and 233 K for D<SUB>2</SUB>O, rather than diverging to infinity. These results point to the existence of the Widom line, a locus of maximum correlation lengths emanating from a critical point in the supercooled regime.</P><P><I>Science</I>, this issue p. 1589; see also p. 1543</P><P>Femtosecond x-ray laser pulses were used to probe micrometer-sized water droplets that were cooled down to 227 kelvin in vacuum. Isothermal compressibility and correlation length were extracted from x-ray scattering at the low–momentum transfer region. The temperature dependence of these thermodynamic response and correlation functions shows maxima at 229 kelvin for water and 233 kelvin for heavy water. In addition, we observed that the liquids undergo the fastest growth of tetrahedral structures at similar temperatures. These observations point to the existence of a Widom line, defined as the locus of maximum correlation length emanating from a critical point at positive pressures in the deeply supercooled regime. The difference in the maximum value of the isothermal compressibility between the two isotopes shows the importance of nuclear quantum effects.</P>

Control of compliant legged quadruped robots in the workspace

Gor, M M,Pathak, P M,Samantaray, A K,Yang, J-M,Kwak, S W SAGE Publications 2015 Simulation Vol.91 No.2

<P>Locomotion control of a quadruped robot requires a well-defined gait pattern (i.e., a coordinated actuation of its four legs in some particular fashion with respect to time). It is of practical importance to move the leg tips in a desired trajectory in order to achieve specific objectives such as to avoid obstacles, minimize energy consumption and locomotion time. Along with body displacement, body orientation is an equally important limit parameter during each leg step of the gait pattern. There are several possible gait patterns that maintain stable and aesthetically pleasing locomotion, and most of these are biologically inspired. This article presents quadruped locomotion control in the workspace through a novel control scheme in which the leg forward motion is controlled in the workspace while the body forward motion is controlled by providing the required effort directly to the joint actuators. In this control approach, the leg tip trajectory error drives a proportional-integral controller that is then transformed through the Jacobian to generate the corrective joint torques. For the body forward motion, leg motion is arrested and the joints are provided with opposite motion, which are controlled by a proportional-integral-derivative controller. The proposed method is simple and easy to implement in the workspace. The performance of the proposed control scheme is evaluated through simulations and animations.</P>

Fault accommodation in compliant quadruped robot through a moving appendage mechanism

Gor, M.M.,Pathak, P.M.,Samantaray, A.K.,Yang, J.-M.,Kwak, S.W. Elsevier 2018 Mechanism and machine theory Vol.121 No.-

<P><B>Abstract</B></P> <P>Quadruped robots provide better stability and speed in comparison to other legged robots. However, its joint actuator or sensor failure severely affects locomotion. Strategies for actuator and sensor fault accommodation in a compliant legged quadruped are presented here. A pair of orthogonally mounted moving appendages mechanism is proposed here to accommodate locked joint failure. These appendages as rack mounted inertias perform controlled motion during actuator failure. A strategy for sensor fault accommodation is also presented. A three-dimensional multi-body dynamics model of quadruped robot and its fault accommodation strategies are developed using bond graph modeling approach. The control performance is validated both through simulations and experiments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Locked-joint and sensor faults of a quadruped robot are detected and isolated. </LI> <LI> Fault tolerant operation of a quadruped robot is considered for various missions. </LI> <LI> Actuator faults are accommodated with controlled moving appendages. </LI> <LI> Sensor fusion is used to reconstruct faulty sensor data. </LI> <LI> Online system reconfiguration is validated using simulations and experiments. </LI> </UL> </P>

Nutrient Utilization and Compensatory Growth in Crossbred (Bos indicus×Bos taurus) Calves

Santra, A.,Pathak, N.N. Asian Australasian Association of Animal Productio 1999 Animal Bioscience Vol.12 No.8

A feeding trial was carried out over 238 days to determine the effect of compensatory growth in crossbred calves having 166 kg body weight. Fifteen crossbred calves were divided into two groups of five calves (G1 group) and ten calves (G2 group) as per randomized block design. Growth study was conducted on the feeding of wheat straw based diet containing 60 and 30 percent concentrate supplying equal amount of protein in group G1 and G2 respectively for 119 days (phase - I). At the end of phase-I, calves of G2 group were subdivided in to two groups (G3 and G4). One sub group (G4) received 60% concentrate in their diet (during 120 to 238 days of experiment) while other subgroup G3 received 30% concentrate in their diet (phase-II). The calves of G1 group continued to receive the same diet as during phase-I experiment. Mean DM intake was significantly higher in calves fed high level of concentrate (in G1 and G4 groups), which resulted in significantly higher digestibility of all nutrients except NDF. Nitrogen balance was positive in all the groups and showed significant differences in phase-II (higher nitrogen retention in G4 group than G1 group). ME intake was significantly affected by the level of dietary concentrate, being higher in high concentrate fed group (G1 and G4 than G2 and G3 group). Higher daily body weight gain in the calves of G4 group during phase-II than in G1 and G3 groups was due to compensatory growth on shifting animals from low concentrate to high concentrate based ration. Average daily body weight gain was higher in phase-I than in the phase-II. Protein and energy intake per unit body weight gain were significantly lower in calves fed high concentrate diet.