16,705 research outputs found
Theoretical studies in interstellar cloud chemistry
This final report represents the completion of the three tasks under the purchase order no. SCPDE5620,1,2F. Chemical composition of gravitationally contracting, but otherwise quiescent, interstellar clouds and of interstellar clouds traversed by high velocity shocks, were modeled in a comprehensive manner that represents a significant progress in modeling these objects. The evolutionary chemical modeling, done under this NASA contract, represents a notable advance over the 'classical' fixed condition equilibrium models because the evolutionary models consider not only the chemical processes but also the dynamical processes by which the dark interstellar clouds may have assumed their present state. The shock calculations, being reported here, are important because they extend the limited chemical composition derivable from dynamical calculations for the total density and temperature structures behind the shock front. In order to be tractable, the dynamical calculations must severely simplify the chemistry. The present shock calculations take the shock profiles from the dynamical calculations and derive chemical composition in a comprehensive manner. The results of the present modeling study are still to be analyzed with reference to astronomical observational data and other contemporary model predictions. As far as humanly possible, this analysis will be continued with CRE's (Creative Research Enterprises's) IR&D resources, until a sponsor is found
Biosorption of Hexavalent Chromium Using Bark of Cassia spectabilis
Biosorption is a relatively new process that has proven very promising in the removal of heavy metal contaminants from aqueous solutions. The biosorption of Cr(VI) from aqueous solution using bark of Cassia spectabilis has been investigated in a batch system. The effect of various parameters such as pH, contact time, adsorbent dosage and initial concentration of Cr(VI) on the biosorption process were studied. The maximum removal of Cr(VI) was observed at pH 1.0. The Study indicated that both biosorption and bioreduction were involved in removal of Cr(VI). The sorption equilibrium exhibited a better fit to the Langmuir isotherm than Freundlich isotherm. The maximum biosorption of Cassia spectabilis bark to remove Cr(VI) was 12.865 mg/g. The dimensionless equilibrium parameter, RL, signifies a favorable adsorption of Cr(VI) on the adsorbent and is found to be 0.441 (0 < RL<1). Pseudo first-order and second order kinetic models were used to evaluate the mechanism of adsorption. Kinetic evaluation of the experimental data showed that the biosorption process follows pseudo- second order kinetic model.Keywords: Hexavalent chromium; Biosorption; Cassia spectabilis bark; Adsorption isotherm; Adsorption kineti
Effect of source and methods of zinc application on corn productivity, nitrogen and zinc concentrations and uptake by high quality protein corn (Zea mays)
Results of a field study conducted at the Indian Agricultural Research Institute, New Delhi, India showed that the combined application of soil + foliar (in two sprays at tasseling and initiation of flowering) produced significantly more grain and stover yields than either soil or foliar applications alone. Application of Zn-coated urea was better than soil application of Zn sulphate with regard to grain and stover yields. The combined application also recorded the highest Zn concentration in corn grain as well as in stover, with the treatments falling in the following order: combined ˃ foliar ˃ soil through Zn-coated urea ˃ soil. This is an important finding for the agronomic biofortification of Zn in corn.Keywords: Crude protein; foliar application of zinc, zinc biofortification, zinc-coated urea, zinc sulphat
Implementation of optimal solution for network lifetime and energy consumption metrics using improved energy efficient LEACH protocol in MANET
In current scenarios MANET mainly focus on low power battery operated devices. Moreover in a MANET transmission of large data consumes more energy that affects the performance of network, energy consumption, throughput, end to end delay, and packet overhead. The sum of these parameter metrics measure must be taken into account to increase the life-time and network energy efficiency. The main constraint in WSN is due to the restricted power in a node, which cannot be substituted. The node senses the data and it is moved towards the sink. This action of data movement needs to be efficient and the usage of battery in the sensor node requires to be efficiently employed to improve the network lifetime. The development of the energy efficient algorithms is of primary concern in the research arena of MANET. In any network, most of the routing protocols are focused directly to collect and bifurcate the large data for long distance communication. The prime goal of this research focused to identifies and survey more suitable routing protocol for MANET. That consumed less energy and increase life time of network. In this paper the author made on attempt on improved energy efficient LEACH protocol for MANET to reduce the energy dissipation that to life time of the network during the data transmission between source nodes and destination nodes
Modelling of a Vibro-Impact Self-Propelled Capsule in the Small Intestine
This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.This paper studies the modelling of a vibro-impact self-propelled capsule system in the small intestinal
tract. Our studies focus on understanding the dynamic characteristics of the capsule and its performance
in terms of the average speed and energy efficiency under various system and control parameters, such as
capsule’s radius and length, and the frequency and magnitude of sinusoidal excitation. We find that the
resistance from the small intestine will be larger once capsule’s size or instantaneous velocity increases.
From our extensive numerical calculations, optimum system and control parameters are obtained for
prototype design and fabrication. It is suggested that increasing forcing magnitude or choosing forcing
frequency greater than the natural frequency of its inner mass can benefit the average speed of the
capsule, and the radius of the capsule should be slightly larger than the radius of the small intestine in
order to generate a reasonable resistance for capsule progression. Finally, the locomotion of the capsule
along an inclined intestinal tract is tested, and the best radius and forcing magnitude of the capsule are
also determined.Engineering and Physical Sciences Research Council (EPSRC)National Natural Science Foundation of ChinaInternational S&T Cooperation and Exchanges of Sichuan provinceFundamental Research Funds for the Central Universitie
Analytical Model of Adaptive CSMA-CA MAC for Reliable and Timely Clustered Wireless Multi-Hop Communication
Reliability and delay of a single cluster wireless network is well analysed in the literature. Multi-hop communication over the number of clusters is essential to scale the network. Analytical model for reliability and end-to-end delay optimization for multi-hop clustered network is presented in this paper. Proposed model is a three dimensional markov chain. Three dimensions of markov model are the adaptable mac parameters of CSMA-CA. Model assumes wakeup rates for each cluster. Results show that reliability and delay are significantly improved than previous analytical models proposed. It has been observed that overall reliability of multi-hop link is improved, with reduction in end-to-end delay is reduced even at lower wakeup rates of a cluste
Context aware building energy management system with heterogeneous wireless network architecture
Energy wastage in buildings is to be minimized to reduce the carbon footprint of electricity. Wireless sensor and actor networks (WSAN) have been providing solutions for effective energy management within buildings. In this paper, we present a decisive server based context aware energy management system for smart buildings through Cyber Physical System (CPS) models. A layered architecture for building energy management is proposed to enhance scalability of the system. Heterogeneous wireless network based multiple radio gateway is proposed and implemented to make the system more adaptive to different applications catering to variable data rates. A smart room test bed is deployed in the IIT Hyderabad campus, where the decisive server collects various physical parameters through sensors, and based on the context generates wireless control messages to power electronics based actuators. Integrating context awareness into the system increases the efficiency in terms of energy savings and was observed to be significant, around 30%. The paper also presents a detailed analysis on the turnaround time required to realise the real saving after recovering investments. Applications are developed to integrate smart phones and tabloids providing web enablement to the end user. In this paper, each of the sensors and actuators in the smart room are associated with a state machine, which enables modelling of the system using Hybrid automata for future scope of applications
Modelling of capsule-intestine contact for a self-propelled capsule robot via experimental and numerical investigation
This is the final version. Available on open access from Springer Verlag via the DOI in this recordThis paper studies the modelling of capsuleintestine contact through experimental and numerical investigation for designing a self-propelled capsule
robot moving inside the small intestine for endoscopic
diagnosis. Due to the natural peristalsis of the intestinal
tract, capsule-intestine contact is multimodal causing
intermittent high transit speed for the capsule, which
leads to incomplete visualisation of the intestinal surface. Three typical conditions, partial and full contacts,
between the small intestine and the capsule, are considered in this work. Extensive experimental testing and
finite element analysis are conducted to compare the
contact pressure on the capsule. Our analytical, experimental and numerical results show a good agreement. The investigation using a synthetic small intestine shows that the contact pressure could vary from
0.5 [kPa] to 16 [kPa] according to different contact conditions, i.e. expanding or contracting due to the peristalsis of the small intestine. Therefore, a proper control
method or a robust stabilising mechanism, which can
accommodate such a high pressure difference, will be
crucial for designing the robot.Engineering and Physical Sciences Research Council (EPSRC
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