Sajeev, S Nair; Dr.Krishnamoorthy,A(Cochin University of Science and Technology, September 2, 2011)
[+]
[-]
Abstract:
In this thesis we have developed a few inventory models in which items are served to the customers after a processing time. This leads to a queue of demand even when items are available. In chapter two we have discussed a problem involving search of orbital customers for providing inventory. Retrial of orbital customers was also considered in that chapter; in chapter 5 also we discussed retrial inventory model which is sans orbital search of customers. In the remaining chapters (3, 4 and 6) we did not consider retrial of customers, rather we assumed the waiting room capacity of the system to be arbitrarily large. Though the models in chapters 3 and 4 differ only in that in the former we consider positive lead time for replenishment of inventory and in the latter the same is assumed to be negligible, we arrived at sharper results in chapter 4. In chapter 6 we considered a production inventory model with production time distribution for a single item and that of service time of a customer following
distinct Erlang distributions. We also introduced protection of production and service stages and investigated the optimal values of the number of stages to be protected.
Description:
Department of Mathematics,
Cochin University of Science And Technology.
Remadevi,S; Narayanan Namboodiri,M N(Department of Mathematics,Faculty of Science, 2003)
[+]
[-]
Abstract:
This study is to look the effect of change in the ordering of the Fourier system on Szegö’s classical observations of asymptotic distribution of eigenvalues of finite Toeplitz forms.This is done by checking proofs and Szegö’s properties in the new set up.The Fourier system is unconditional [19], any arbitrary ordering of the Fourier system forms a basis for the Hilbert space L2 [-Π, Π].Here study about the classical Szegö’s theorem.Szegö’s type theorem for operators in L2(R+) and check its validity for certain multiplication operators.Since the trigonometric basis is not available in L2(R+) or in L2(R) .This study discussed about the classes of orderings of Haar System in L2 (R+) and in L2(R) in which Szegö’s Type TheoreT Am is valid for certain multiplication operators.It is divided into two sections. In the first section there is an ordering to Haar system in L2(R+) and prove that with respect to this ordering, Szegö’s Type theorem holds for general class of multiplication operators Tƒ with multiplier ƒ ε L2(R+), subject to some conditions on ƒ.Finally in second section more general classes of ordering of Haar system in L2(R+) and in L2(R) are identified in such a way that for certain classes of multiplication operators the asymptotic distribution of eigenvalues exists.
Veena Gopalan, E; Dr.Anantharaman, M R(Cochin University of Science & Technology, June , 2009)
[+]
[-]
Abstract:
This thesis lays importance in the preparation and characterization of a
few selected representatives of the ferrite family in the nanoregime. The candidates being manganese zinc ferrite and cobalt ferrite prepared by coprecipitation
and sol-gel combustion techniques respectively. The thesis not only
stresses importance on the preparation techniques and optimization of the reaction
conditions, but emphasizes in investigating the various properties namely
structural, magnetic and electrical. Passivated nickel nanocomposites are
synthesized using polystyrene beads and adopting a novel route of ion exchange
reduction. The structural and magnetic properties of these magnetic
nanocomposites are correlated. The magnetocaloric effect (MCE) exhibited by
these materials are also investigated with a view to finding out the potential of
these materials as magnetic refrigerants. Calculations using numerical methods
are employed to evaluate the entropy change on selected samples.
Description:
Department of Physics,
Cochin University of Science & Technology
Hysen, Thomas; Anantharaman, M R(Cochin University of Science and Technology, June , 2013)
[+]
[-]
Abstract:
The development of new materials has been the hall mark of human civilization. The quest for making new devices and new materials has prompted humanity to pursue new methods and techniques that eventually has given birth to modern science and technology. With the advent of nanoscience and nanotechnology, scientists are trying hard to tailor materials by varying their size and shape rather than playing with the composition of the material. This, along with the discovery of new and sophisticated imaging tools, has led to the discovery of several new classes of materials like (3D) Graphite, (2D) graphene, (1D) carbon nanotubes, (0D) fullerenes etc. Magnetic materials are in the forefront of applications and have beencontributing their share to remove obsolescence and bring in new devices based on magnetism and magnetic materials. They find applications in various devices such as electromagnets, read heads, sensors, antennas, lubricants etc. Ferromagnetic as well as ferrimagnetic materials have been in use in the form of various devices. Among the ferromagnetic materials iron, cobalt and nickel occupy an important position while various ferrites finds applications in devices ranging from magnetic cores to sensors.
Description:
Department of Physics, Cochin University of Science and Technology
Abdul Sathar,E I; Muraleedharan Nair,K R(Department of Statistics, Faculty of Science, 2002)
[+]
[-]
Abstract:
The present study focuses attention on defining certain measures of income inequality for the truncated distributions and characterization of probability distributions using the functional form of these measures, extension of some measures of inequality and stability to higher dimensions, characterization of bivariate models using the above concepts and estimation of some measures of inequality using the Bayesian techniques. The thesis defines certain measures of income inequality for the truncated distributions and studies the effect of truncation upon these measures. An important measure used in Reliability theory, to measure the stability of the component is the residual entropy function. This concept can advantageously used as a measure of inequality of truncated distributions. The geometric mean comes up as handy tool in the measurement of income inequality. The geometric vitality function being the geometric mean of the truncated random variable can be advantageously utilized to measure inequality of the truncated distributions. The study includes problem of estimation of the Lorenz curve, Gini-index and variance of logarithms for the Pareto distribution using Bayesian techniques.
George, Joseph; Zakkariya, K A(Cochin University Of Science And Technology, October , 2015)
[+]
[-]
Abstract:
The aim of this study is to investigate the role of operational flexibility for
effective project management in the construction industry.
The specific objectives are to:
a) Identify the determinants of operational flexibility potential
in construction project management
b) Investigate the contribution of each of the determinants to
operational flexibility potential in the construction industry
c) Investigate on the moderating factors of operational
flexibility potential in a construction project environment
d) Investigate whether moderated operational flexibility
potential mediates the path between predictors and effective
construction project management
e) Develop and test a conceptual model of achieving
operational flexibility for effective project management
The purpose of this study is to findout ways to utilize flexibility inorder to manage uncertain project environment and ultimately achieve effective project management. In what configuration these operational flexibility determinants are demanded by construction project environment in order to achieve project success. This research was conducted in three phases, namely: (i) exploratory phase (ii) questionnaire development phase; and (iii) data collection and analysis phase. The study needs firm level analysis and therefore real estate developers who are members of CREDAI, Kerala Chapter were considered. This study provides a framework on the functioning of operational flexibility, offering guidance to researchers and practitioners for discovering means to gain operational flexibility in construction firms. The findings provide an empirical understanding on kinds of resources and capabilities a construction firm must accumulate to respond flexibly to the changing project environment offering practitioners insights into practices that build firms operational flexibility potential. Firms are dealing with complex, continuous changing and uncertain environments due trends of globalization, technical changes and innovations and changes in the customers’ needs and expectations. To cope with the increasingly uncertain and quickly changing environment firms strive for flexibility. To achieve the level of flexibility that adds value to the customers, firms should look to flexibility from a day to day operational perspective. Each dimension of operational flexibility is derived from
competences and capabilities. In this thesis only the influence on customer satisfaction and learning exploitation of flexibility dimensions which directly add value in the customers eyes are studied to answer the followingresearch questions: “What is the impact of operational flexibility on customer satisfaction?.” What are the predictors of operational flexibility in construction industry? .These questions can only be answered after answering the questions like “Why do firms need operational flexibility?” and “how can firms achieve operational flexibility?” in the context of the construction industry. The need for construction firms to be flexible, via the effective utilization of organizational resources and capabilities for improved responsiveness, is important because of the increasing rate of changes in the business environment within which they operate. Achieving operational flexibility is also important because it has a significant correlation with a project effectiveness and hence a firm’s turnover. It is essential for academics and practitioners to recognize that the attainment of operational flexibility involves different types namely: (i) Modification (ii) new product development and (iii) demand management requires different configurations of predictors (i.e., resources, capabilities and strategies). Construction firms should consider these relationships and implement appropriate management practices for developing and configuring the right kind of resources, capabilities and strategies towards achieving different operational flexibility types.
Alex,Mathew; Dr.Madhusoodanan, K N(Cochin University of Science and Technology, June , 2004)
[+]
[-]
Abstract:
The thesis provides an overall review and introduction to amorphous semiconductors, followed by a brief discussion on the important structural models proposed for chalcogenide glasses and their electrical, optional and thermal properties. It also gives a brief description of the Physics of thin films, ion implantation and Photothermal Deflection Spectroscopy. A brief description of the experimental setup of a photothermal deflection spectrometer and the details of the preparation and optical characterization of the thin film samples. It deals with the employment of the subgap optional absorption measurement by PDS to characterize the defects, amorphization and annealing behavior in silicon implanted with B+ ions and the profiles of ion range and vacancy distribution obtained by the TRIM simulation. It reports the results of all absorption measurements by PDS in nitrogen implanted thin film samples of Ge-Se and As-Se systems
Joseph, Lyjo K; Dr. Radhakrishnan, P; Dr.Nampoori,V P N(Cochin University of Science & Technology, November , 2009)
[+]
[-]
Abstract:
Nondestructive photothermal methods as well as optical absorption and fluorescence spectroscopy are utilized to characterise three different materials, both thermally and optically. The possibility of using montmorillonite clay minerals, after textile waste-water treatment, is investigated for further applications. The laser induced luminescence studies and thermal characterisation of certain rare earth titanates prepared by self propagating high temperature synthesis method are also presented. Moreover, effort is made to characterise rare earth doped sol gel silica glasses with the help of these nondestructive techniques.
Description:
International School of Photonics, Cochin University of Science and Technology
Lyjo, Joseph K; Dr. Radhakrishnan, P(Cochin University of Science And Technology, November , 2009)
[+]
[-]
Abstract:
The advent of high optical quality transparent nano—structured glasses, the so-called transparent glass ceramics or vitroceramics disclosed the possibility of producing nano-sized photonic devices based on rare-earth doped up—converters. Transparent glass ceramics have been investigated as hosts for lanthanide ions envisioning the production of materials that are easy to shape and with high performance for photonic applications. Rare earth doped glasses have been extensively studied due to their potential applications in optical devices such as solid state lasers and optical fibers. Various photothermal and optical techniques have been successfully applied for the thermal and optical characterization of these rare earth doped materials. In the present thesis, the effective thermal parameters like thermal diffusivity and thermal effusivity of complex materials for various applications have been investigated using photothermal methods along with their optical characterization utilising the common optical absorption as well as fluorescence spectroscopic techniques. These sensitive optical procedures are also essential for exploiting these materials for further photonic applications.
Description:
School of photonics, Cochin University of Science And Technology
Harilal, S S; Girijavallabhan, C P(Cochin University of Science and Technology, 1997)
[+]
[-]
Abstract:
This thesis is entitled “OPTICAL EMISSION DIAGNOSTICS OF LASER PRODUCED PLASMA FROM GRAPHITE AND YBa2Cu3O7. The work presented in this thesis covers the experimental results on the plasma produced with moderately high power laser with irradiance range in between 10 GW cm 2 to 100 GW cm -2. The characterization of laser produced plasma from solid targets viz. graphite and high temperature superconducting material like YBa2Cu3O7 have been carried out. The fundamental frequency from a Q - switched Nd: YAG laser with 9 ns pulse
duration is used for the present studies. Various optical emission emission diagnostic techniques were employed for the the characterization of the LPP which include emission spectroscopy, time resolved studies, line broadening method etc. In order to understand the physical nature of the LPP like recombination, collisional excitation and the laser interaction with plasma, the time resolved studies offer the most logical approach
Jude Martin, Mendez; Dr.George, K E(Cochin University of Science & Technology, October , 2009)
[+]
[-]
Abstract:
This study was undertaken in order to upgrade blends of HDPE and
PP, two of the most widely used standard plastics so as to widen their
application spectrum. Dicumyl peroxide was used as the modifier for the
upgradation. Optimum concentration of dicumyl peroxide required for
modification was detennined by measurement of mechanical, rheological,
thermal and morphological properties. Selected blends were used to prepare
recyclable composites with nylon clothes by compression moulding. The
composites were characterized by measurement of mechanical and thermal
properties. The composites were recycled and the mechanical propertics of
the recycled material were determined.
Description:
Dept.of Polymer Science and Rubber Technology,
Cochin University of Science and technology