Shear strength response of reinforced pond ash

Reinforced pond ash is a composite material, which can be used as an alternative construction material in the field of geotechnical engineering. To study the shear strength response of reinforced pond ash, a series of unconsolidated undrained (UU) triaxial test has been conducted on both unreinforced and reinforced pond ash. In the present investigation the effects of confining pressure (σ₃), number of geotextile layers (N), and types of geotextiles on shear strength response of pond ash are studied. The results demonstrate that normal stress at failure (σ_1f) increases with increase in confining pressure. The rate of increase of normal stress at failure (σ_1f) is maximum for three layers of reinforcement, while the corresponding percentage increase in σ_1f is around (103%), when the number of geotextile layers increases from two layers to three layers of reinforcement. With increase in confining pressure the increment in normal stress at failure, Δσ increases and attains a peak value at a certain confining pressure (threshold value) after that Δσ becomes more or less constant. The threshold value of confining pressure depends on N, dry unit weight (γ_d) of pond ash, type of geotextile, and also type of pond ash.     

Constructivist Management of Knowledge,Communication and Enterprise Innovation: Lessons from Indian Experience

Prime movers of enterprise innovation are inside the organisation. The enterprise NIIT, studied in this paper, tells us how elicitation and recognition of knowledge and its contents set an enterprise on the move. Recognised knowledge is actionable. Each act of recognition is an addition to knowledge content, and such additions took place in NIIT through acts of communications and self-searching. These contents form a large collage that cannot be strewn into a single novelistic episode. Perspectives and context, motives and suggestions render to each member of the enterprise different disjoint appearances of knowledge. There are thus many knowledge systems and multiple narrations, each with small episode-like finality. Enterprise innovation is achieved not through any grand episodic integration of all knowledge contents, but by constructively eliciting further new contents of knowledge, and encouraging acts of communications and discourses on this new knowledge. Constructive management of knowledge and communication towards enterprise innovation has thus been defined. Through such constructive management, NIIT enabled itself innovationally and empowered its members in eliciting knowledge and acting communicatively. A critical feature of knowledge work is that it requires multidisciplinary expertise and mutual learning in order to achieve a complex synthesis of highly specialised state-of-the-art technologies and knowledge domains. A convivial work culture and a culture of communicative acts enable sharing of the non-informatised yet recognised contents of knowledge.     

Aesthetics of navigational performance in hypertext

A hypertext learner navigates with a instinctive feeling for a knowledge. The learner does not know her queries, although she has a feeling for them. A learners navigation appears as complete upon the emergence of an aesthetic pleasure, called rasa. The order of arrival or the associational logic and even the temporal order are not relevant to this emergence. The completeness of aesthetics is important. The learner does not look for the intention of the writer, neither does she look for significance. Lexia has a suggestive power and she is suggested in the arrival of aesthetics. Hypertext learning does not depend on communication. The learner in her pleasure transgresses the bounds of space-time to be in communion with several writers/learners. Hypertext learning does not appear to be fundamentally different from the analog learning; however, in performance, as in navigation, the learner assumes a mental state that helps her in her emergence into aesthetic bliss, of an arrival to the completed lexial navigation. This completeness is owing to aesthetics and is not owing to either the semantics or the query-fulfilling qualities.     

Robust control of HIV infection by antiretroviral therapy: a super‐twisting sliding mode control approach

Acquired immune deficiency syndrome is an epidemic infectious disease which is caused by the human immunodeficiency virus (HIV) and that has proliferated across worldwide. It has been a matter of concern for the scientific community to develop an antiretroviral therapy, which will prompt a rapid decline in viral abundance. With this motivation, this study proposes the design of a robust super twisting sliding mode controller based on output information for an uncertain HIV infection model. The control objective is to decrease the concentration of infected CD4+ T cells to a specified level by drug administration using only the output information of the uncertain HIV infection model which is total CD4+ T cell concentration. The robust output‐feedback controller has been developed in combination with a robust exact differentiator, functioning as an observer. The reported analysis demonstrates that the approach proposed here is capable of ensuring robust performance under several operating conditions, measurement and modelling error, parametric uncertainties and external disturbances and the simulation results prove the proficiency of the controller proposed.Inspec keywords: control system synthesis, observers, robust control, drugs, medical control systems, diseases, uncertain systems, variable structure systems, patient treatment, feedback, cellular biophysics, microorganismsOther keywords: robust control, antiretroviral therapy, sliding mode control approach, acquired immune deficiency syndrome, epidemic infectious disease, human immunodeficiency virus, scientific community, robust super, mode controller, output information, uncertain HIV infection model, control objective, infected CD4, total CD4, T cell concentration, robust output‐feedback controller, robust exact differentiator, robust performance     

Mixed valency character of bismuth in ferrite lattices

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

An accurate technique of measurement of a transducer output by using a modified two core saturable reactor

Saturable reactor or transductor used as a magnetic modulator or amplifier for the measurement of the small value DC output signal of a transducer may suffer from error due to the fact that a part of the current drawn from the transducer by the transductor unit is utilized to magnetize the core material. In this paper a modified two core saturable reactor circuit has been proposed to eliminate this error. This unit also minimizes some other errors like common mode error, material error, etc. Theory of operation and design of the circuit has been explained in this paper. The circuit has been tested by using a millivolt input signal as well as a thermocouple to measure temperature. The experimental results are presented in this paper. Linear static characteristic graphs have been observed.     

Modification of an Infrared Spectrophotometer to Study Nerve Excitation

A modification to a Perkin-Elmer model 521 infrared spectrophotometer is described which allows a difference spectrum to be obtained from the same sample of a nerve between resting and excited states. Signal processing using time averaging and digital smoothing are employed to improve the signal-to-noise ratio (S/N).     

Temperature behavior and compensation of light-emitting diode

This letter offers a fresh insight into the behavior of light-emitting diode (LED) over temperature. Theoretically and by measurement, it has been shown that equi-intensity curves in the diodes current-voltage plane are nearly a straight line over a very wide range of temperatures. Based on this property, bias voltage and resistance value of a bias circuit have been realized and practical measurement shows the peak-to-peak light intensity variation decreases from 99 % (in case of fixed current bias) to 6 % over the temperature range of -20 C to +80 C for the LED IN6092. This circuit uses no separate temperature sensor or compensating mechanism, but responds directly to the junction temperature of the diodes. This prevents any error caused by temperature gradient, or by self-heating due to power dissipation in the diode.     

Synthesis,Characterization, and drug release study of acrylamide‐co‐itaconic acid based smart hydrogel

A new kind of pH and temperature responsive poly(acrylamide‐co‐itaconic acid) hydrogel was prepared by free radical polymerization using ammonium persulfate as initiator and different comonomer ratios. The hydrogels were characterized in terms of chemical composition, swelling‐deswelling behavior, morphology, crystallographic behavior, and drug release properties. All the hydrogels showed high swelling ability in aqueous solutions, the maximum being at pH 7. Swelling decreased on either side of pH 7 (i.e., both in acidic and alkaline region) and increased with increase in temperature. The hydrogel with 10 mol% itaconic acid (IA) absorbed maximum water among the copolymer gels. The cellular structures of the hydrogels were clearly revealed by microscopic analysis and SEM pictures. Swelling of the gels in water followed non‐Fickian type of diffusion principle. The hydrogel was proved to be a controlled release vehicle, for example in drug delivery by using its smart properties. The hydrogel with 10 mol% IA also absorbed maximum amount of drug (ascorbic acid) under study. Incorporation of drug in hydrogel matrix was established from XRD peak analysis. POLYM. ENG. SCI., 55:113–122, 2015. © 2014 Society of Plastics Engineers